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Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T03:37:41Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC following the atmospheric river that took place in mid November. November 23, 2021.|360x360px]]During November of 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupted British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives. For an extended period of time, Vancouver was effectively cut off from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, which overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. The many effects of climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, as well as the likelihood of similar events occuring in the future, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has undergone drastic changes to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Before its draining, Sumas Lake saw much natural variability, which was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides <ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor <ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake due to its unpredictable behaviour. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, Sumas Lake was gone; it had been drained <ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. They often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, Sumas Lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, Sumas Lake was historically the center of a dynamic floodplain landscape <ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life <ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring <ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area <ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost <ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada <ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain <ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, causing severe damage to both the environment and infrastructure in surrounding areas, in addition to creating public safety and human health risks.

=== Human Impacts ===

During the floods and resulting landslides, five individuals were confirmed dead and over 3,000 residents were forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed <ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding were not aware that their homes and farms were located on a former lakebed.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (mainly nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Operators remove boulders from the bottom of a cliffside, in response to flooding and mudslides. Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecedented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infrastructure such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks <ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds <ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many waterways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle, losses of homes on farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost during the flooding as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. The repairs required to fix widespread power outages added to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC Transportation Minister, estimated that the government would likely end up spending around $1 billion in highway repairs <ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's federal economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses to respond to BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies coming together to discuss the best strategies to manage the crises and mitigate the flood impacts. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Protected underway to restore river structure in response to flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies, which was titled: "Recovering Together: November 2021 Atmospheric River" <ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long-term risk assessments. In response to these assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife <ref name=":8" />. In addition to these hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability <ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways <ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential for future flooding, unstable banks and navigational challenges <ref name=":8" />. Due to these findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action <ref name=":8" />.

The federal government made an especially significant contribution in supporting recovery through the Disaster Financial Assistance Arrangements (DFAA) program. This program from the Government of Canada contributed over $1 billion to help cover costs caused by the 2021 BC floods, including an additional $556,955,800 in 2023 to continue the ongoing relief efforts <ref name=":9">{{Cite web|last=Canada|first=P.S.|date=2023, February 23|title=Government of Canada provides disaster recovery funding to British Columbia for 2021 flood.|url=https://www.canada.ca/en/public-safety-canada/news/2023/02/government-of-canada-provides-disaster-recovery-funding-to-british-columbia-for-2021-flood.html|url-status=live|access-date=April 10, 2026}}</ref>. The money was not only used to restore public services and infrastructure, but also supported evacuation protocols, individual aid, farmland, and small business owners to mitigate economic and environmental impacts. The Government of Canada stated that they were devoted to Canadian citizens and will do as much as they can to help citizens prepare for and resist any future extreme weather events <ref name=":9" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|400x400px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural runoff, and other sources which can negatively impact surrounding environmental and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, reactivating supply chains <ref name=":3" />.

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing water or separating the water from the land. Despite numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be floodsafe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different measures in place. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to the Mayor of Abbotsford, Henry Braun, the cost of operations to meet the provincial design standards would range from $2.5 billion to $2.8 billion <ref name=":32" />. [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

The largest shift in preventative measures following the floods occurred in 2024 when the province moved from "reactive" emergency response and towards "integrated flood management" <ref name=":10">{{Cite web|date=December 17, 2025|title=Recurring flood risk requires sustained response|url=https://www.ubcm.ca/about-ubcm/latest-news/recurring-flood-risk-requires-sustained-response#:~:text=%E2%80%9CWithin%20the%20first%20six%20months,noticed%20and%20to%20be%20heard.|url-status=live|access-date=12 April 2026|website=UBCM}}</ref>. The introduction of the BC Flood Strategy in May 2024 led to more coordinated and long-term flood risk management, and re-enforces British Columbia's position that significant flood management duties (such as diking authority) should be assigned to local governments <ref name=":10" />. Despite this seemingly large step in the right direction, failure to properly fund the strategy has exposed the gap between intentions and actual action being made to mitigate damage and protect communities from flood events. This failure to fund the new program, along with failure to fund improvements for the dikes and water pumps suggests that the province is not willing to allocate enough funds to this issue, despite the risk it proposes to citizens of British Columbia.

Central to this strategy is a transition toward watershed-based planning, which shifts the primary focus from isolated local infrastructure to the hydrological health of entire river basins <ref name=":11">{{Cite web|last=Ministry of Water|date=March 21, 2024|title=From Flood Risk to Resilience: A B.C. Flood Strategy to 2035|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/integrated-flood-hazard-mgmt/bc_flood_strategy.pdf|url-status=live|access-date=12 April 2026|website=gov.bc}}</ref>. This approach prioritizes "Room for the River" tactics—such as the implementation of setback dikes and the restoration of natural floodplains—to reduce water velocity and peak surge levels before they reach urban centers <ref>{{Cite web|last=City of Merritt Flood Mitigation Department|date=November 18, 2025|title=Dike 129/130 Program: Setback Dikes and River Corridor Management|url=https://flood.merritt.ca/project/dike-129-130/|url-status=live|access-date=12 April 2026|website=Merritt Flood Mitigation}}</ref>. By integrating nature-based solutions like wetland preservation and upper-watershed forest management, the province aims to utilize natural landscapes as biological sponges to mitigate runoff <ref name=":11" />. However, the successful execution of these plans requires unprecedented cross-jurisdictional cooperation between municipalities and First Nations, as well as sustained provincial funding to move beyond theoretical modeling and into physical land-use changes <ref name=":11" />.
==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T03:37:05Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC following the atmospheric river that took place in mid November. November 23, 2021.|360x360px]]During November of 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupted British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives. For an extended period of time, Vancouver was effectively cut off from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, which overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. The many effects of climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, as well as the likelihood of similar events occuring in the future, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has undergone drastic changes to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Before its draining, Sumas Lake saw much natural variability, which was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides <ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor <ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake due to its unpredictable behaviour. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, Sumas Lake was gone; it had been drained <ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. They often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, Sumas Lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, Sumas Lake was historically the center of a dynamic floodplain landscape <ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life <ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring <ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area <ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost <ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada <ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain <ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, causing severe damage to both the environment and infrastructure in surrounding areas, in addition to creating public safety and human health risks.

=== Human Impacts ===

During the floods and resulting landslides, five individuals were confirmed dead and over 3,000 residents were forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed <ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding were not aware that their homes and farms were located on a former lakebed.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (mainly nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Operators remove boulders from the bottom of a cliffside, in response to flooding and mudslides. Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecedented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infrastructure such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks <ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds <ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many waterways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle, losses of homes on farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost during the flooding as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. The repairs required to fix widespread power outages added to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC Transportation Minister, estimated that the government would likely end up spending around $1 billion in highway repairs <ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's federal economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses to respond to BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies coming together to discuss the best strategies to manage the crises and mitigate the flood impacts. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Protected underway to restore river structure in response to flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies, which was titled: "Recovering Together: November 2021 Atmospheric River" <ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long-term risk assessments. In response to these assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife <ref name=":8" />. In addition to these hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability <ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways <ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential for future flooding, unstable banks and navigational challenges <ref name=":8" />. Due to these findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action <ref name=":8" />.

The federal government made an especially significant contribution in supporting recovery through the Disaster Financial Assistance Arrangements (DFAA) program. This program from the Government of Canada contributed over $1 billion to help cover costs caused by the 2021 BC floods, including an additional $556,955,800 in 2023 to continue the ongoing relief efforts <ref name=":9">{{Cite web|last=Canada|first=P.S.|date=2023, February 23|title=Government of Canada provides disaster recovery funding to British Columbia for 2021 flood.|url=https://www.canada.ca/en/public-safety-canada/news/2023/02/government-of-canada-provides-disaster-recovery-funding-to-british-columbia-for-2021-flood.html|url-status=live|access-date=April 10, 2026}}</ref>. The money was not only used to restore public services and infrastructure, but also supported evacuation protocols, individual aid, farmland, and small business owners to mitigate economic and environmental impacts. The Government of Canada stated that they were devoted to Canadian citizens and will do as much as they can to help citizens prepare for and resist any future extreme weather events <ref name=":9" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|410x410px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural runoff, and other sources which can negatively impact surrounding environmental and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, reactivating supply chains <ref name=":3" />.

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing water or separating the water from the land. Despite numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be floodsafe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different measures in place. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to the Mayor of Abbotsford, Henry Braun, the cost of operations to meet the provincial design standards would range from $2.5 billion to $2.8 billion <ref name=":32" />. [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

The largest shift in preventative measures following the floods occurred in 2024 when the province moved from "reactive" emergency response and towards "integrated flood management" <ref name=":10">{{Cite web|date=December 17, 2025|title=Recurring flood risk requires sustained response|url=https://www.ubcm.ca/about-ubcm/latest-news/recurring-flood-risk-requires-sustained-response#:~:text=%E2%80%9CWithin%20the%20first%20six%20months,noticed%20and%20to%20be%20heard.|url-status=live|access-date=12 April 2026|website=UBCM}}</ref>. The introduction of the BC Flood Strategy in May 2024 led to more coordinated and long-term flood risk management, and re-enforces British Columbia's position that significant flood management duties (such as diking authority) should be assigned to local governments <ref name=":10" />. Despite this seemingly large step in the right direction, failure to properly fund the strategy has exposed the gap between intentions and actual action being made to mitigate damage and protect communities from flood events. This failure to fund the new program, along with failure to fund improvements for the dikes and water pumps suggests that the province is not willing to allocate enough funds to this issue, despite the risk it proposes to citizens of British Columbia.

Central to this strategy is a transition toward watershed-based planning, which shifts the primary focus from isolated local infrastructure to the hydrological health of entire river basins <ref name=":11">{{Cite web|last=Ministry of Water|date=March 21, 2024|title=From Flood Risk to Resilience: A B.C. Flood Strategy to 2035|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/integrated-flood-hazard-mgmt/bc_flood_strategy.pdf|url-status=live|access-date=12 April 2026|website=gov.bc}}</ref>. This approach prioritizes "Room for the River" tactics—such as the implementation of setback dikes and the restoration of natural floodplains—to reduce water velocity and peak surge levels before they reach urban centers <ref>{{Cite web|last=City of Merritt Flood Mitigation Department|date=November 18, 2025|title=Dike 129/130 Program: Setback Dikes and River Corridor Management|url=https://flood.merritt.ca/project/dike-129-130/|url-status=live|access-date=12 April 2026|website=Merritt Flood Mitigation}}</ref>. By integrating nature-based solutions like wetland preservation and upper-watershed forest management, the province aims to utilize natural landscapes as biological sponges to mitigate runoff <ref name=":11" />. However, the successful execution of these plans requires unprecedented cross-jurisdictional cooperation between municipalities and First Nations, as well as sustained provincial funding to move beyond theoretical modeling and into physical land-use changes <ref name=":11" />.
==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T03:36:20Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC following the atmospheric river that took place in mid November. November 23, 2021.|360x360px]]During November of 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupted British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives. For an extended period of time, Vancouver was effectively cut off from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, which overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. The many effects of climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, as well as the likelihood of similar events occuring in the future, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has undergone drastic changes to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Before its draining, Sumas Lake saw much natural variability, which was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides <ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor <ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake due to its unpredictable behaviour. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, Sumas Lake was gone; it had been drained <ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. They often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, Sumas Lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, Sumas Lake was historically the center of a dynamic floodplain landscape <ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life <ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring <ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area <ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost <ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada <ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain <ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, causing severe damage to both the environment and infrastructure in surrounding areas, in addition to creating public safety and human health risks.

=== Human Impacts ===

During the floods and resulting landslides, five individuals were confirmed dead and over 3,000 residents were forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed <ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding were not aware that their homes and farms were located on a former lakebed.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (mainly nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Operators remove boulders from the bottom of a cliffside, in response to flooding and mudslides. Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecedented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infrastructure such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks <ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds <ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many waterways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle, losses of homes on farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost during the flooding as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. The repairs required to fix widespread power outages added to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC Transportation Minister, estimated that the government would likely end up spending around $1 billion in highway repairs <ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's federal economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses to respond to BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies coming together to discuss the best strategies to manage the crises and mitigate the flood impacts. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Protected underway to restore river structure in response to flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies, which was titled: "Recovering Together: November 2021 Atmospheric River" <ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long-term risk assessments. In response to these assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife <ref name=":8" />. In addition to these hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability <ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways <ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential for future flooding, unstable banks and navigational challenges <ref name=":8" />. Due to these findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action <ref name=":8" />.

The federal government made an especially significant contribution in supporting recovery through the Disaster Financial Assistance Arrangements (DFAA) program. This program from the Government of Canada contributed over $1 billion to help cover costs caused by the 2021 BC floods, including an additional $556,955,800 in 2023 to continue the ongoing relief efforts <ref name=":9">{{Cite web|last=Canada|first=P.S.|date=2023, February 23|title=Government of Canada provides disaster recovery funding to British Columbia for 2021 flood.|url=https://www.canada.ca/en/public-safety-canada/news/2023/02/government-of-canada-provides-disaster-recovery-funding-to-british-columbia-for-2021-flood.html|url-status=live|access-date=April 10, 2026}}</ref>. The money was not only used to restore public services and infrastructure, but also supported evacuation protocols, individual aid, farmland, and small business owners to mitigate economic and environmental impacts. The Government of Canada stated that they were devoted to Canadian citizens and will do as much as they can to help citizens prepare for and resist any future extreme weather events <ref name=":9" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|420x420px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural runoff, and other sources which can negatively impact surrounding environmental and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, reactivating supply chains <ref name=":3" />.

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing water or separating the water from the land. Despite numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be floodsafe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different measures in place. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to the Mayor of Abbotsford, Henry Braun, the cost of operations to meet the provincial design standards would range from $2.5 billion to $2.8 billion <ref name=":32" />. [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

The largest shift in preventative measures following the floods occurred in 2024 when the province moved from "reactive" emergency response and towards "integrated flood management" <ref name=":10">{{Cite web|date=December 17, 2025|title=Recurring flood risk requires sustained response|url=https://www.ubcm.ca/about-ubcm/latest-news/recurring-flood-risk-requires-sustained-response#:~:text=%E2%80%9CWithin%20the%20first%20six%20months,noticed%20and%20to%20be%20heard.|url-status=live|access-date=12 April 2026|website=UBCM}}</ref>. The introduction of the BC Flood Strategy in May 2024 led to more coordinated and long-term flood risk management, and re-enforces British Columbia's position that significant flood management duties (such as diking authority) should be assigned to local governments <ref name=":10" />. Despite this seemingly large step in the right direction, failure to properly fund the strategy has exposed the gap between intentions and actual action being made to mitigate damage and protect communities from flood events. This failure to fund the new program, along with failure to fund improvements for the dikes and water pumps suggests that the province is not willing to allocate enough funds to this issue, despite the risk it proposes to citizens of British Columbia.

Central to this strategy is a transition toward watershed-based planning, which shifts the primary focus from isolated local infrastructure to the hydrological health of entire river basins <ref name=":11">{{Cite web|last=Ministry of Water|date=March 21, 2024|title=From Flood Risk to Resilience: A B.C. Flood Strategy to 2035|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/integrated-flood-hazard-mgmt/bc_flood_strategy.pdf|url-status=live|access-date=12 April 2026|website=gov.bc}}</ref>. This approach prioritizes "Room for the River" tactics—such as the implementation of setback dikes and the restoration of natural floodplains—to reduce water velocity and peak surge levels before they reach urban centers <ref>{{Cite web|last=City of Merritt Flood Mitigation Department|date=November 18, 2025|title=Dike 129/130 Program: Setback Dikes and River Corridor Management|url=https://flood.merritt.ca/project/dike-129-130/|url-status=live|access-date=12 April 2026|website=Merritt Flood Mitigation}}</ref>. By integrating nature-based solutions like wetland preservation and upper-watershed forest management, the province aims to utilize natural landscapes as biological sponges to mitigate runoff <ref name=":11" />. However, the successful execution of these plans requires unprecedented cross-jurisdictional cooperation between municipalities and First Nations, as well as sustained provincial funding to move beyond theoretical modeling and into physical land-use changes <ref name=":11" />.
==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T03:35:05Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.|360x360px]]During November of 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupted British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives. For an extended period of time, Vancouver was effectively cut off from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, which overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. The many effects of climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, as well as the likelihood of similar events occuring in the future, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has undergone drastic changes to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Before its draining, Sumas Lake saw much natural variability, which was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides <ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor <ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake due to its unpredictable behaviour. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, Sumas Lake was gone; it had been drained <ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. They often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, Sumas Lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, Sumas Lake was historically the center of a dynamic floodplain landscape <ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life <ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring <ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area <ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost <ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada <ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain <ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, causing severe damage to both the environment and infrastructure in surrounding areas, in addition to creating public safety and human health risks.

=== Human Impacts ===

During the floods and resulting landslides, five individuals were confirmed dead and over 3,000 residents were forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed <ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding were not aware that their homes and farms were located on a former lakebed.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (mainly nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Operators remove boulders from the bottom of a cliffside, in response to flooding and mudslides. Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecedented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infrastructure such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks <ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds <ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many waterways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle, losses of homes on farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost during the flooding as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. The repairs required to fix widespread power outages added to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC Transportation Minister, estimated that the government would likely end up spending around $1 billion in highway repairs <ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's federal economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses to respond to BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies coming together to discuss the best strategies to manage the crises and mitigate the flood impacts. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Protected underway to restore river structure in response to flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies, which was titled: "Recovering Together: November 2021 Atmospheric River" <ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long-term risk assessments. In response to these assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife <ref name=":8" />. In addition to these hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability <ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways <ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential for future flooding, unstable banks and navigational challenges <ref name=":8" />. Due to these findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action <ref name=":8" />.

The federal government made an especially significant contribution in supporting recovery through the Disaster Financial Assistance Arrangements (DFAA) program. This program from the Government of Canada contributed over $1 billion to help cover costs caused by the 2021 BC floods, including an additional $556,955,800 in 2023 to continue the ongoing relief efforts <ref name=":9">{{Cite web|last=Canada|first=P.S.|date=2023, February 23|title=Government of Canada provides disaster recovery funding to British Columbia for 2021 flood.|url=https://www.canada.ca/en/public-safety-canada/news/2023/02/government-of-canada-provides-disaster-recovery-funding-to-british-columbia-for-2021-flood.html|url-status=live|access-date=April 10, 2026}}</ref>. The money was not only used to restore public services and infrastructure, but also supported evacuation protocols, individual aid, farmland, and small business owners to mitigate economic and environmental impacts. The Government of Canada stated that they were devoted to Canadian citizens and will do as much as they can to help citizens prepare for and resist any future extreme weather events <ref name=":9" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|420x420px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural runoff, and other sources which can negatively impact surrounding environmental and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, reactivating supply chains <ref name=":3" />.

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing water or separating the water from the land. Despite numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be floodsafe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different measures in place. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to the Mayor of Abbotsford, Henry Braun, the cost of operations to meet the provincial design standards would range from $2.5 billion to $2.8 billion <ref name=":32" />. [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

The largest shift in preventative measures following the floods occurred in 2024 when the province moved from "reactive" emergency response and towards "integrated flood management" <ref name=":10">{{Cite web|date=December 17, 2025|title=Recurring flood risk requires sustained response|url=https://www.ubcm.ca/about-ubcm/latest-news/recurring-flood-risk-requires-sustained-response#:~:text=%E2%80%9CWithin%20the%20first%20six%20months,noticed%20and%20to%20be%20heard.|url-status=live|access-date=12 April 2026|website=UBCM}}</ref>. The introduction of the BC Flood Strategy in May 2024 led to more coordinated and long-term flood risk management, and re-enforces British Columbia's position that significant flood management duties (such as diking authority) should be assigned to local governments <ref name=":10" />. Despite this seemingly large step in the right direction, failure to properly fund the strategy has exposed the gap between intentions and actual action being made to mitigate damage and protect communities from flood events. This failure to fund the new program, along with failure to fund improvements for the dikes and water pumps suggests that the province is not willing to allocate enough funds to this issue, despite the risk it proposes to citizens of British Columbia.

Central to this strategy is a transition toward watershed-based planning, which shifts the primary focus from isolated local infrastructure to the hydrological health of entire river basins <ref name=":11">{{Cite web|last=Ministry of Water|date=March 21, 2024|title=From Flood Risk to Resilience: A B.C. Flood Strategy to 2035|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/integrated-flood-hazard-mgmt/bc_flood_strategy.pdf|url-status=live|access-date=12 April 2026|website=gov.bc}}</ref>. This approach prioritizes "Room for the River" tactics—such as the implementation of setback dikes and the restoration of natural floodplains—to reduce water velocity and peak surge levels before they reach urban centers <ref>{{Cite web|last=City of Merritt Flood Mitigation Department|date=November 18, 2025|title=Dike 129/130 Program: Setback Dikes and River Corridor Management|url=https://flood.merritt.ca/project/dike-129-130/|url-status=live|access-date=12 April 2026|website=Merritt Flood Mitigation}}</ref>. By integrating nature-based solutions like wetland preservation and upper-watershed forest management, the province aims to utilize natural landscapes as biological sponges to mitigate runoff <ref name=":11" />. However, the successful execution of these plans requires unprecedented cross-jurisdictional cooperation between municipalities and First Nations, as well as sustained provincial funding to move beyond theoretical modeling and into physical land-use changes <ref name=":11" />.
==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T00:58:19Z

FletcherLucas: /* Future Recommendations and Preventative Measures */

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.|360x360px]]During November of 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Mike Farnworth, Minister of Public Safety and Solicitor General, and Rob Fleming, Minister of Transportation and Infrastructure, meets with community members and First Nations leaders affected by the flooding and mudslides in the Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

The overall impact of the flood debris led to extensive damage to the Nicola Valley area, affecting the livelihoods of many Indigenous communities.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Mike Farnworth, Minister of Public Safety and Solicitor General, and Rob Fleming, Minister of Transportation and Infrastructure, meets with community members and First Nations leaders affected by the flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies titled "Recovering Together: November 2021 Atmospheric River"<ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long term risk assessments. In response to their assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife<ref name=":8" />. In addition to previously stated hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability<ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways<ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential future flooding, unstable banks and navigational challenges<ref name=":8" />. In response to their findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action<ref name=":8" />.

The federal government made an especially significant contribution in supporting recovery through the Disaster Financial Assistance Arrangements (DFAA) program. This program from the Government of Canada contributed over $1 billion to help cover costs caused by the 2021 BC floods, including an additional $556,955,800 in 2023 to continue ongoing relief efforts<ref name=":9">{{Cite web|last=Canada|first=P.S.|date=2023, February 23|title=Government of Canada provides disaster recovery funding to British Columbia for 2021 flood.|url=https://www.canada.ca/en/public-safety-canada/news/2023/02/government-of-canada-provides-disaster-recovery-funding-to-british-columbia-for-2021-flood.html|url-status=live|access-date=April 10, 2026}}</ref>. The money is being used to not only to restore public services and infrastructure but also supports evacuation protocols, individual aid, farmland, and small business owners to mitigate economic and environmental impacts. The Government of Canada has stated that they are devoted to Canadian citizens and will do as much as they can to help citizens prepare and resist any future extreme weather events<ref name=":9" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|420x420px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T00:48:23Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
[[File:51985291800 9139af9576 o.jpg|thumb|Mike Farnworth, Minister of Public Safety and Solicitor General, and Rob Fleming, Minister of Transportation and Infrastructure, meets with community members and First Nations leaders affected by the flooding and mudslides in the Merritt area, March 23, 2022.]]
The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

The overall impact of the flood debris led to extensive damage to the Nicola Valley area, affecting the livelihoods of many Indigenous communities.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Mike Farnworth, Minister of Public Safety and Solicitor General, and Rob Fleming, Minister of Transportation and Infrastructure, meets with community members and First Nations leaders affected by the flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies titled "Recovering Together: November 2021 Atmospheric River"<ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long term risk assessments. In response to their assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife<ref name=":8" />. In addition to previously stated hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability<ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways<ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential future flooding, unstable banks and navigational challenges<ref name=":8" />. In response to their findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action<ref name=":8" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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FletcherLucas: Uploaded a work by Government of British Columbia from Flickr with UploadWizard

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Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

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FletcherLucas: /* Government Response and Recovery Efforts */

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

The overall impact of the flood debris led to extensive damage to the Nicola Valley area, affecting the livelihoods of many Indigenous communities.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.
[[File:51985023279 f2c0451d5b o.jpg|thumb|Mike Farnworth, Minister of Public Safety and Solicitor General, and Rob Fleming, Minister of Transportation and Infrastructure, meets with community members and First Nations leaders affected by the flooding and mudslides in the Merritt area, March 23, 2022.]]
A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies titled "Recovering Together: November 2021 Atmospheric River"<ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long term risk assessments. In response to their assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife<ref name=":8" />. In addition to previously stated hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability<ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways<ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential future flooding, unstable banks and navigational challenges<ref name=":8" />. In response to their findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action<ref name=":8" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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[[Category:Conservation]]

File:51985023279 f2c0451d5b o.jpg

2026-04-13T00:40:16Z

FletcherLucas: Uploaded a work by Government of British Columbia from Flickr with UploadWizard

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T00:29:06Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

The overall impact of the flood debris led to extensive damage to the Nicola Valley area, affecting the livelihoods of many Indigenous communities.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

A project by the government of BC, which was coordinated with Indigenous groups, conservation organizations, and local agencies titled "Recovering Together: November 2021 Atmospheric River"<ref name=":8" />, assessed environmental, public safety and infrastructure, cultural aesthetic and community values along with stability and long term risk assessments. In response to their assessments, debris from hard to reach areas was removed to avoid hazards posed to ecosystems, water quality and wildlife<ref name=":8" />. In addition to previously stated hazards, accessible debris that posed threats to downstream communities and infrastructure was also removed. Along with debris that obstructed water flow, impacted flood control systems and disrupted land stability<ref name=":8" />. After actions were carried out, the province reported that sediment debris in water bodies contributed to significant erosion and shifting slopes along waterways<ref name=":8" />. These findings brought researchers to the conclusion that the material deposits altered the shape and slope of watercourses, in turn creating hazards that increased the risk to public safety. These risks were summarized as potential future flooding, unstable banks and navigational challenges<ref name=":8" />. In response to their findings, 128 sediment sites were assessed, with 17 project locations being approved for emergency response action<ref name=":8" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-13T00:01:24Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

The overall impact of the flood debris led to extensive damage to the Nicola Valley area, affecting the livelihoods of many Indigenous communities.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-12T23:58:19Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. The unprecidented rainfall contributed to the destabilization of slopes, erosion on shorelines, and damage to critical infasturcture such as dikes and highways. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-12T23:54:18Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric river had severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, caused severe damage to both the environment and infastucture in surrounding areas, in addition to public safety and human health risks.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-12T23:50:12Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]From November 13 to 15th 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, the nature and infrastructure in the Southern BC area, as well as citizens of that area.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

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[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-12T23:47:42Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, the nature and infrastructure in the Southern BC area, as well as citizens of that area.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into river streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-12T23:46:56Z

FletcherLucas: Added information

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban development resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, the nature and infrastructure in the Southern BC area, as well as citizens of that area.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.

Due to the flooding, many were forced to stay home and not travel within the flooded region for extended periods of time. For many days during November of 2021, using smartphone tracking data, it was found that there was virtually no travel between the cities of Hope, Merritt, and Chilliwack (all three are within the Fraser Valley and were affected by the floods)<ref>{{Cite journal|last=Liao|first=Enqi|date=May 24, 2024|title=Travel Behavior during the 2021 British Columbia Floods Using De-identified Network Mobility Data|url=doi.org/10.32866/001c.117422|journal=Resilience Findings}}</ref>. In the following weeks, travel between the cities slowly began to increase, but it took extended time for typical travel between the cities to return.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water from farmland, leading to eutrophication. Eutrophication occurs when nutrient runoff (often from agricultural fertilizers) causes rapid algal growth. When the algae dies, the bacteria that decompose the algae consume dissolved oxygen, creating hypoxic (not enough oxygen) conditions. These hypoxic conditions can suffocate aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.

The flooding not only contributed to land destruction, but had severe impacts on rivers and natural water systems. Extensive human made debris was dispersed across multiple waterway systems. Among the debris, entire homes and buildings were washed into rivers streams, along with vehicles, propane and fuel tanks<ref name=":8">{{Cite web|last=Government of British Columbia|title=Recovering Together: November 2021 Atmospheric River|url=https://storymaps.arcgis.com/stories/ecff219fba9f453bbf0f771918ccdd7b|url-status=live|access-date=12 April, 2026}}</ref>. Additionally, rivers experienced pollution through shipping containers and damaged bridges, further contributing to environmental degradation. The impacts of the debris posed risks to public safety, water quality, and infrastructure. In addition to human made debris, waterways experienced extensive damage through the distribution of natural debris. Rivers were affected by the runoff of logs and fuel left by wildfire, uprooted trees due to erosion, along with the accumulation of rocks and boulders in river beds<ref name=":8" />. With the presence of natural debris, buildups obstructed water flow, compromised the structure of many water ways and increased risk to further damage in the future flooding events.

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

Large impacts of the flooding was also seen on British Columbia's roads. In 2023, the British Columbia Transportation Ministry said that it was expected that the repairs for major damages to BC's highways had grown to approximately $1 billion. At the time, $250 million in repairs had been done on highways one (the Trans-Canada highway), five, and eight. However, more repairs were needed to restore the British Columbia's highways and attempt to make them more resilient to future atmospheric rivers and flooding, which is why Rob Fleming, BC's Transportation Minister, estimated that the government would likely end up spending around $1 billion<ref>{{Cite news|url=https://globalnews.ca/news/9468280/highway-flood-repairs-1billion/|title=B.C. highway flood repair costs expected to balloon to $1 billion|last=Garrett|first=Catherine|date=February 7, 2023|work=Global News|access-date=April 11, 2026}}</ref>.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. the prompted organized activity across many levels of the Canadian government, which includes municipal, provincial, and federal agencies to come together to discuss the best strategies to manage the crises and mitigate the impact. The different levels of the Canadian government came up with many ways to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Floodwaters can carry contaminants from excess sediment, agricultural run off, and many more sources which can negatively impact the the surrounding environment and human health. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future by implementing reinforced structure and better drainage systems. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed necessary in order for the location to be flood safe going forward. Despite having this knowledge for many years, there has been no action to actually improve upon the current status of the different emplacements. Part of the reason that no real progress has been made to upgrade the preventative measures is because according to Henry Braun, the cost of operations to meet the provint [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-11T00:32:14Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contributing factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, and agricultural fields, in an effort to further residential and urban development in the area<ref name=":4" />. The changes in the lake's historical wide array of seasonal depth and the progression of urban developement resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64% of streams being lost<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditional use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, the nature and infastucture in the Southern BC area, as well as citizens of that area.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake. For the ''Semá:th'' People native to that region, the return of the lake was expected<ref name=":4" />.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water, leading to eutrophication. This process depletes dissolved oxygen effectively suffocating fish and other aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This caused Canadian Governments of many levels to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-11T00:22:49Z

FletcherLucas:

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake<ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>.

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large changes in depth and size depending on the season, snowmelt, and even the Pacific tides<ref name=":7">{{Cite journal|last=Murton|first=James|date=January 2008|title=Creating Order: the Liberals, the Landowners, and the Draining of Sumas Lake, British Columbia|url=https://www.proquest.com/docview/216123962/fulltextPDF/D6152C190D6F41EBPQ/1?accountid=14656&sourcetype=Scholarly%20Journals|journal=Environmental History|via=ProQuest}}</ref>.

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing. In 1858, the discovery of gold in the Fraser Valley meant that the Stó:lō were forced into reserves by James Douglas, British Columbia's governor<ref name=":7" />. In the 1970s, there began to be discussion and legislation surrounding diking the Sumas Lake. By 1920, the conversation had shifted towards draining the lake, with hopes of accessing the fertile soil at the bottom of the Sumas Lake and avoiding its unpredictable shifts. By June 26, 1924, the Sumas Lake was gone<ref name=":7" />. Today, the lake remains drained and is mostly covered by agricultural lands.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

In addition to the unprecedented atmospheric river, the Sumas lake was a contibuting factor to the severity of flooding. Between the Sumas Mountain and Vedder Mountain in the Lower Fraser Valley, the Sumas lake was historically the center of a dynamic floodplain landscape<ref name=":4" />. The Indigenous food system in the area was supported by a high amount of animal and plant life<ref name=":4" />. In addition to its biodiversity, the lake could vary from an area of 9,000 acres (3,642 ha) and a depth of 3 meters in the winter, to an area of 26,000 acres (10,522 ha) and depth of 11 meters in the spring<ref name=":4" />. During the past 150 years, the Lower Fraser has seen changes within in its vast network of rivers, creeks, wetlands, and floodplains. These ecosystems have been developed into a series of ditches, canals, dikes, floodgates, agricultural fields, in response to residential and urban development<ref name=":4" />. The changes in the lakes historical wide array of season depth and urban developement resulted in 30% of native vegetation remaining intact and over 85% of floodplain habitat and 64%<ref name=":4" />. In the early 1920's, The Sumas Lake was drained after an act in a Canada-wide process of land dispossession from Indigenous peoples in Canada<ref name=":4" />. The loss of traditonal use and knowledge resulted in mismanagement practices that increased the flood risk in the area. By the mid 1920's, a plan was put in motion to drain the lake in order to further expand agricultural practices in the area. By 1924, the Chilliwack River had been diverted west, draining the lake through the Sumas Drainage Canal and into the Fraser River around the northeastern tip of the Sumas Mountain<ref name=":4" />. Despite the loss of the lake, the low elevation remained, resulting in permanent flood risk for the newly developed agricultural area.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, the nature and infastucture in the Southern BC area, as well as citizens of that area.

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref>. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />. Farms, homes, businesses, and transportation corridors flooded, causing destruction to livelihoods and infrastructure. Many of those affected by the flooding, were not aware that their homes and farms were located on a former lakebed—Sumas Lake. For the ''Semá:th'' People native to that region, the return of the lake was expected<ref name=":4" />.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water, leading to eutrophication. This process depletes dissolved oxygen effectively suffocating fish and other aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />. In addition to flood damage to farmers, the Insurance Bureau of Canada reported an estimated $9 billion Canadian dollars (CAD) in insured damages, contributing to the further economic impacts <ref>{{Cite web|last=S. Richards-Thomas, J. Déry, E. Stewart, M. Thériault,|first=Tamar, Stephen J. Déry, Ronald, Julie|date=12 June, 2024|title=Climatological context of the mid-November 2021 floods in the province of British Columbia, Canada|url=https://www.sciencedirect.com/science/article/pii/S2212094724000665|url-status=live|access-date=10 April, 2026}}</ref>. Power outages also contributed to further economic damage.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response and Recovery Efforts ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This caused Canadian Governments of many levels to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls to track changes in water composition, ensuring that contamination levels do not further worsen beyond expectations<ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade routes. Repair crews often had to reconstruct entire sections of highways due to erosion while reinforcing them to prevent similar events from happening in the future. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":32">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be "in less-than-fair condition" and that 71% simply wouldn't hold in the event of a flood, rendering them useless <ref name=":32" />.

Along with the dikes, a water pump system upgrade was deemed [[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-09T19:08:39Z

FletcherLucas: /* References */

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction<ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref> ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Sumas prairie has experienced extreme change to appear the way that it does today. Historically, the eastern part of the Sumas Prairie was occupied by Sumas Lake, before its eventual draining for agricultural purposes between 1920 and 1924. Farmers sought the fertile soil at the bottom of the lake. <ref>{{Cite web|date=January 7, 2025|title=Sumas River and Canal|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects/sumas-river-and-canal|url-status=live|website=Government of British Columbia}}</ref>

Historically, Sumas Lake saw much natural variability, which mainly was caused by the Lake's connection to the Fraser River, which is in turn connected to the Pacific Ocean. The water levels of the Fraser River typically rise in the summer due to snowmelt. This unpredictability in the Fraser directly translated to the Sumas Lake, with the water levels of the Lake seeing large

The Stó:lō people are an Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years. They had a deep connection to Sumas Lake, both for cultural purposes and for fishing and agriculture.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, BC's nature, and the citizens of British Columbia

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4" />. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water, leading to eutrophication. This process depletes dissolved oxygen effectively suffocating fish and other aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This caused Canadian Governments of many levels to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade infrastructure. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Future Recommendations and Preventative Measures ==
Following the recovery efforts, several preventative measures were put into the place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":3" />. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be in less than
[[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-04-09T19:02:44Z

FletcherLucas: Added image and description

= Environmental and Social Impacts of the 2021 Flooding Season in Southern BC =
== Introduction<ref name=":4">{{Cite web|last=Finn et al.|date=02 June 2024|title=Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake|url=https://www.frontiersin.org/journals/conservation-science/articles/10.3389/fcosc.2024.1380083/full|url-status=live|access-date=08 March 2026}}</ref> ==
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
== History of the Sumas Prairie and its Colonization ==
The Stó:lō are the Indigenous group that have historically inhabited the Fraser Valley for at least 4,000 years.

==Converging Factors and Causes of Flooding==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, BC's nature, and the citizens of British Columbia

=== Human Impacts ===

During the floods and the resulting landslides, five individuals were confirmed dead, with well over 3,000 residents forced out of their homes and evacuated in the Abbotsford area alone <ref name=":4" />. In the Sumas Prairie, the former Sumas Lake refilled, displacing thousands and destroying homes built on the historic lake bed<ref name=":4" />.

Floodwaters transported significant amounts of debris, sediment, and bacteria. E. coli counts at several locations, such as the Pitt Meadows Shoreline, exceeded Canadian Drinking Water Quality Guidelines (CDWQG) following sanitary sewer overflows <ref name=":5">{{Cite web|last=Minton et al.|date=June 2022|title=Water Quality Assessment of the Fraser River Following
the November 2021 Floods|url=https://www2.gov.bc.ca/assets/gov/environment/air-land-water/water/flood-response-and-the-environment/water-quality/water_quality_assessment_of_fraser_river_2021_floods.pdf|url-status=live|access-date=09 March 2026}}</ref>. Sanitary sewer overflows (SSOs) and the overflow of septic systems led to dangerous spikes in bacteria and other waterborne pathogens which pose risks to human health <ref name=":5" />.
=== Environmental Impacts ===

The floods severely degraded the Lower Fraser Valley's critical habitat, which is essential for Pacific salmon and sturgeon. Rapidly rising waters caused massive sediment movement which buried salmon spawning grounds and destroyed eggs. Scientists note that the full impact on salmon populations may not be known until their 2 to 5 year life cycles are complete in spawning season of 2026 <ref>{{Cite web|last=DFO|date=2022|title=Extreme environmental impacts on Pacific salmon|url=https://www.pac.dfo-mpo.gc.ca/pacific-smon-pacifique/environmental-impacts-environnementaux-eng.html|url-status=live|access-date=09 March 2026}}</ref>.

Excessive nutrients (nitrogen and phosphorus) washed into slow moving bodies of water, leading to eutrophication. This process depletes dissolved oxygen effectively suffocating fish and other aquatic organisms <ref>{{Cite web|last=Ross et al.|date=November 2022|title=A lake re-emerges: Analysis of contaminants in the Semá:th X̱ó:tsa (Sumas Lake) region following the BC floods of 2021|url=https://www.raincoast.org/reports/flood/|url-status=live|access-date=09 March 2026}}</ref>.

The death of over 670,000 farm animals created a biological hazard through an increase of immediate groundwater contamination and the spread of disease <ref name=":6">{{Cite web|last=Province of British Columbia|date=2024|title=Flood debris management projects|url=https://www2.gov.bc.ca/gov/content/environment/flood-projects|url-status=live|access-date=09 March 2026}}</ref>. Crews eventually removed over 16,000 metric tons of natural and man-made debris (including 98 vehicles and 4 bridges) from provincial waterways to prevent further ecological blockages from occurring as a result of the floods <ref name=":6" />.
=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response ==

The provincial government of British Columbia declared a state of emergency and implemented a variety of disaster responses in the event of BC's 2021 floods. This caused Canadian Governments of many levels to respond with recovery and evacuation plans as well as emergency response units to address damage to infrastructure, the environment, and the evacuation of affected communities . Initiatives from the provincial government focused on post-flood repair and clean up by implementing flood debris management programs to restore and improve waterways <ref name=":6" />.

Water quality assessments were conducted by researchers and the government to evaluate and record potential pollutants in the water within the Fraser River Valley area after the floods. Additionally, the research group wanted to determine if the flood event caused accelerated pollution of contaminants compared to average rainfalls <ref name=":5" />.

Infrastructure of highways and railways where prioritized for repair from flood and landslide damage by the government as they were critical transportation and trade infrastructure. These repairs reconnected the Lower Mainland with the rest of Canada, which reactivated many supply chains<ref name=":3" />.

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Recovery and Long-Term Effects ==

The months following the flood consisted of constant recovery and construction efforts across the Fraser valley. Waterways were restored and assessed for any contaminants lingering the water so they may not affect local ecosystem as well as land and food supplies <ref name=":5" />. While flood debris management was implemented to improve river systems and clean up any damage or wreckage left after the flood <ref name=":6" />.

==Future Recommendations and Preventative Measures==
Following the recovery efforts, several preventative measures were put into the place in order to prevent further flooding across British Columbia's lower mainland - from upstream of Fraser Valley all the way down to the Pacific Ocean <ref name=":3" />. The most widespread measure used across this area is dikes, large engineered barriers intended to prevent flooding by either containing, or separating the water from the land. Despite a numerous dikes being in place, Principle Flood Management Engineer Monica Mannerström noted that a study found 87% of dikes to be in less than
[[File:54989012923 95b4e84af5 o.jpg|thumb|Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 15, 2026. ]]

==References==
Please use the Wikipedia reference style. Provide a citation for every sentence, statement, thought, or bit of data not your own, giving the author, year, AND page.
For dictionary references for English-language terms, I strongly recommend you use the Oxford English Dictionary. You can reference foreign-language sources but please also provide translations into English in the reference list.

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

File:54989012923 95b4e84af5 o.jpg

2026-04-09T18:37:51Z

FletcherLucas: Uploaded a work by Government of British Columbia from Flickr – BC Government Photos https://www.flickr.com/photos/bcgovphotos/54989012923/in/album-72177720304423311 with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Premier David Eby, Minister Kelly Greene, Minister Lana Popham and others visit Abbotsford on December 16, 2025.}}
|date=2025-12-16
|source=Flickr – BC Government Photos
https://www.flickr.com/photos/bcgovphotos/54989012923/in/album-72177720304423311
|author=Government of British Columbia
|permission=
|other versions=
}}

=={{int:license-header}}==
{{cc-by-sa-2.5-ca}}

[[Category:CONS200]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-03-09T04:37:36Z

FletcherLucas: Added image and description

Add your introduction here<ref>Sample Reference</ref>, covering general background information about the topic (e.g. location, duration).

Include the scope/scale of the problem, intensity/frequency/severity of negative impacts, variables influencing those impacts and any other relevant information needed for understanding the issue.

== Introduction ==
In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref name=":3">{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287?utm_source=chatgpt.com|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8?utm_source=chatgpt.com|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]

==Background==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

==Impacts ==
The flooding caused by the 2021 atmospheric rivers has severe impacts throughout British Columbia. These include impacts on British Columbia's major industries such as agriculture and the transportation of goods, BC's nature, and the citizens of British Columbia.

=== Human Impacts ===

=== Environmental Impacts ===

=== Economic Impacts ===

The British Columbia provincial government estimated that BC's farmers lost approximately $285 million in flood-related damages <ref name=":3" />. This estimate took all of BC's various agricultural sectors into account, including how many acres of plants were lost, losses of cattle and homes on dairy farms, and the tens of thousands of hens lost in flooding. It is also key to highlight that the damage goes beyond the crops and cattle lost, as the farmland itself may suffer from long-term damage <ref name=":3" />.

The Trans-Canada highway, which spans from British Columbia to Newfoundland and Labrador, is Canada's main route for transporting goods across the country. The highway suffered immense damage during 2021's floods, interrupting the key transportation route through BC <ref name=":3" />. In addition, the flooding made transporting goods to and from the Port of Vancouver increasingly complicated. The Port of Vancouver is a key Canadian asset for international trade, and its disruption had negative effects on Canada's economy.

== Government Response ==

[[File:Screenshot 2026-03-08 at 9.26.41 PM.png|thumb|340x340px|Minister Kelly Greene and Minister Lana Popham meet with Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre. December 12, 2026. ]]

== Recovery and Long-Term Effects ==

=== Future Risk ===

==Conclusion==
You should conclude your Wiki paper by summarizing the topic, or some aspect of the topic.[[File:Crepuscular Rays in GGP.jpg|thumbnail|right|Images from [https://commons.wikimedia.org/wiki/Main_Page Wikimedia Commons] can be embedded easily.]]
==References==
Please use the Wikipedia reference style. Provide a citation for every sentence, statement, thought, or bit of data not your own, giving the author, year, AND page.
For dictionary references for English-language terms, I strongly recommend you use the Oxford English Dictionary. You can reference foreign-language sources but please also provide translations into English in the reference list.

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

File:Screenshot 2026-03-08 at 9.26.41 PM.png

2026-03-09T04:32:15Z

FletcherLucas: Uploaded a work by The Government of British Columbia (BC GOV photos) from https://www.flickr.com/photos/bcgovphotos/54981004465/in/album-72177720304423311/ with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Minister Kelly Greene and Minister Lana Popham were joined by Abbotsford Mayor Ross Siemens and technical experts to give the latest update on flood response in British Columbia. Following the update, Minister Greene and the Mayor toured areas impacted by the atmospheric river and the emergency operations centre.}}
|date=2025-12-12
|source=https://www.flickr.com/photos/bcgovphotos/54981004465/in/album-72177720304423311/
|author=The Government of British Columbia (BC GOV photos)
|permission=
|other versions=
}}

=={{int:license-header}}==
{{cr-cdn-gov}}

[[Category:UBC]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-03-09T02:30:53Z

FletcherLucas:

Add your introduction here<ref>Sample Reference</ref>, covering general background information about the topic (e.g. location, duration).

Include the scope/scale of the problem, intensity/frequency/severity of negative impacts, variables influencing those impacts and any other relevant information needed for understanding the issue.

== Introduction ==
In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref>{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287?utm_source=chatgpt.com|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8?utm_source=chatgpt.com|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]

==Background==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

==Impacts ==
Describe your analysis and evaluation of additional solutions and recommendations from a technical, social, cultural, economic, financial, political and/or legal points of view (not all of these categories will be relevant to all situations);

=== Human Impacts ===

=== Environmental Impacts ===

=== Economic Impacts ===

== Government Response ==

== Recovery and Long-Term Effects ==

=== Future Risk ===

==Conclusion==
You should conclude your Wiki paper by summarizing the topic, or some aspect of the topic.[[File:Crepuscular Rays in GGP.jpg|thumbnail|right|Images from [https://commons.wikimedia.org/wiki/Main_Page Wikimedia Commons] can be embedded easily.]]
==References==
Please use the Wikipedia reference style. Provide a citation for every sentence, statement, thought, or bit of data not your own, giving the author, year, AND page.
For dictionary references for English-language terms, I strongly recommend you use the Oxford English Dictionary. You can reference foreign-language sources but please also provide translations into English in the reference list.

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-03-09T02:30:35Z

FletcherLucas: Background

Add your introduction here<ref>Sample Reference</ref>, covering general background information about the topic (e.g. location, duration).

Include the scope/scale of the problem, intensity/frequency/severity of negative impacts, variables influencing those impacts and any other relevant information needed for understanding the issue.

== Introduction ==
In November 2021, Southwestern BC experienced unprecedented rainfall that caused catastrophic flooding. The flooding caused widespread damage to infrastructure, agriculture, communities and ecosystems. The event resulted in damage to 1,000 farms, 15,000 hectares of land, 2.5 million livestock, and disrupting British Columbia’s road and railway infrastructure <ref>{{Cite web|last=Senate of Canada|date=October, 2022|title=Treading water: The impact of and response to the 2021 British Columbia floods|url=https://sencanada.ca/content/sen/committee/441/AGFO/reports/2022-10-27_B.C.Floods_AltText_e.pdf.|url-status=live|access-date=March 8, 2026}}</ref>. Further impacts such as floods and landslides resulted in the loss of at least five lives, cutting Vancouver off entirely from the rest of Canada by road and rail, making the event the costliest natural disaster in the province's history <ref name=":0">{{Cite web|last=Gillett et al.|date=27 April 2022|title=Human influence on the 2021 British Columbia floods|url=https://www.sciencedirect.com/science/article/pii/S2212094722000287?utm_source=chatgpt.com|url-status=live|archive-date=]|access-date=8 March 2026}}</ref>. The flooding was driven by a powerful atmospheric river that produced two days of intense rainfall, overwhelming regional drainage and flood control systems that were not designed for such extreme precipitation events. The intense rainfall the area experienced overwhelmed regional drainage and flood control systems that were not designed for such extreme precipitation events. Climate change likely increased the intensity and likelihood of the event <ref name=":1">{{Cite web|last=Environment and Climate Change Canada|date=March 2021|title=Human influence on the 2021 British Columbia floods|url=https://osdp-psdo.canada.ca/dp/en/search/metadata/ECCC-CURATED-1-FE331596-5442-4615-B477-2C46F07D12B8?utm_source=chatgpt.com|url-status=live|access-date=8 March 2026}}</ref>, highlighting the need for improved mitigation measures and informing policy changes aimed at reducing future flood risks.
[[File:51704524798 a634de57b5 o.jpg|thumb|Flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.]]

==Background==
Atmospheric rivers are long and narrow filaments of concentrated water vapour, typically found in wetter west coast regions <ref name=":2">{{Cite web|last=Ralph et al.|date=01 April 2018|title=Defining “Atmospheric River”: How the Glossary of Meteorology Helped Resolve a Debate|url=https://journals.ametsoc.org/view/journals/bams/99/4/bams-d-17-0157.1.xml|url-status=live|access-date=8 March 2026}}</ref>. “Atmospheric rivers often produce heavy rainfall when the moist air is forced upward by mountains or other rising air currents. <ref name=":2" />. These conditions contributed to the extreme rainfall and flooding in southern British Columbia in November 2021. Historically, westerly atmospheric river events of this magnitude are approximately one in ten year events in the region's current climate. Human-induced climate change has increased the likelihood of such events by at least 60% <ref name=":0" />, and studies indicate that the probability of extreme streamflow events in October–December has risen by an estimated 120–330% due to human influence <ref name=":1" />.

==Impacts ==
Describe your analysis and evaluation of additional solutions and recommendations from a technical, social, cultural, economic, financial, political and/or legal points of view (not all of these categories will be relevant to all situations);

=== Human Impacts ===

=== Environmental Impacts ===

=== Economic Impacts ===

== Government Response ==

== Recovery and Long-Term Effects ==

=== Future Risk ===

==Conclusion==
You should conclude your Wiki paper by summarizing the topic, or some aspect of the topic.[[File:Crepuscular Rays in GGP.jpg|thumbnail|right|Images from [https://commons.wikimedia.org/wiki/Main_Page Wikimedia Commons] can be embedded easily.]]
==References==
Please use the Wikipedia reference style. Provide a citation for every sentence, statement, thought, or bit of data not your own, giving the author, year, AND page.
For dictionary references for English-language terms, I strongly recommend you use the Oxford English Dictionary. You can reference foreign-language sources but please also provide translations into English in the reference list.

'''Note:''' Before writing your wiki article on the UBC Wiki, it may be helpful to review the tips in [https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles Wikipedia: Writing better articles].<ref>En.wikipedia.org. (2018). Writing better articles. [online] Available at: https://en.wikipedia.org/wiki/Wikipedia:Writing_better_articles [Accessed 18 Jan. 2018].</ref>

<references/>

{{Projectbox CONS200
|names=
|share=no
}}

[[Category:Conservation]]

Course:CONS200/2026WT2/Environmental and social impacts of the 2021 flooding season in southern BC

2026-03-09T00:33:03Z

FletcherLucas: Introduction and Image

File:51704524798 a634de57b5 o.jpg

2026-03-09T00:25:39Z

FletcherLucas: Uploaded a work by Province of British Columbia (BC Gov Photos) from https://www.flickr.com/photos/bcgovphotos/51704524798/in/album-72157717726814421/ with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Lana Popham, Minister of Agriculture, Food and Fisheries, MLAs Ian Paton and Pam Alexis, witness the flood devastation over Abbotsford and Chilliwack BC, November 23, 2021.}}
|date=2021-11-25
|source=https://www.flickr.com/photos/bcgovphotos/51704524798/in/album-72157717726814421/
|author=Province of British Columbia (BC Gov Photos)
|permission=
|other versions=
}}

=={{int:license-header}}==
{{cr-cdn-gov}}

[[Category:UBC]]