New study identifies the cost of restoring the Sumas Xhotsa (Lake) as a tool for reconciliation, climate adaptation, and ecosystem restoration

In collaboration with Indigenous leaders, lawyers, and researchers from the Indigenous-led Lower Fraser Fisheries Alliance, the Martin Conservation Decisions Lab at the University of British, and West Coast Environmental Law, Raincoast authored a new study that analyzes Indigenous laws and oral traditions with an assessment of the economic costs of ‘managed retreat’, the purposeful relocation of people and infrastructure out of harm’s way, as an innovative solution to flood risk.

The Sumas Xhotsa was a rich ecosystem and Indigenous food system 

The Sumas Xhotsa (Lake), located in the floodplain of the Fraser River (Stó:lō) and its tributaries, was the epicentre of the Semá:th Nation territory and a broader Indigenous food system that supported Coast Salish communities. The lake was a biodiverse aquatic ecosystem that supported five species of Pacific salmon, two species of sturgeon, medicinal plants, and was a key stopover site for waterfowl and migratory birds on the Pacific flyway. Of the 102 species at risk of extinction in the Lower Fraser watershed (Kehoe et al. 2020), 72 are likely to have inhabited the Sumas Lake region.   

 In 1924, the lake was forcefully drained by the colonial government in an effort to convert this important ecosystem to agricultural land. Now, the Sumas Xhotsa is known as the “Sumas Prairie”, and its lakebed is the location of industrial agriculture for livestock and crops. Very little natural habitat remains for aquatic or terrestrial species where this important ecosystem and Indigenous food system once thrived. 

Atmospheric rivers return the Sumas Xhotsa 

In November 2021, a series of atmospheric rivers converged on the Lower Mainland of BC and northern Washington State, causing rivers to break their restraining dikes and extensive flooding to occur in the Lower Mainland of BC. This flooding saw the return of the Sumas Xhotsa and the evacuation of thousands of people, the loss of livestock and crops, and millions of dollars in damage to homes and infrastructure. 

With climate models predicting increased intensity and severity of precipitation events, the research team saw an opportunity to re-examine the status quo of flood adaptation – that is, to build grey infrastructure higher and to further restrict waterways with each flood event. 

Our peer-reviewed paper offers a missing narrative to the discussion of flood management and climate change adaptation and that is grounded in Indigenous knowledge and ecosystem-based governance. 

We drew upon the legal traditions of the Lower Fraser First Nations to outline the governing principles and responsibilities that have guided Indigenous management of the area since time immemorial. We also conducted a spatial and economic analysis of the costs of rebuilding measures that have been proposed in response to the flooding, and present an alternative solution to flooding by revitalizing the lake via managed retreat. 

Laws of the Xhotsa

We identified how legal processes practiced by Lower Fraser First Nations can inform the current response to climate change-induced disasters, such as the November, 2021 floods. The legal processes shown in the sxwōxwiyám/s ̌xʷə ̌ xʷəyém (‘stories of the distant past’ or ‘tell stories’) illustrate the historic baseline conditions against which cumulative effects are to be assessed, providing a standard for restoring ecosystems today. When these stewardship responsibilities are not followed, resulting in standards not being met, impacts to the land, water, animals, and people are felt across the region. Moving forward will require engaging Indigenous Knowledge in the assessment of cumulative effects to ecological, cultural, and economic well-being of the region in the recovery of such events. 

Costs of recovery options

Building on the Indigenous legal principles, we assessed the cost of reclaiming and revitalizing Sumas Lake through managed retreat utilizing a spatial analysis of the assessed values of the properties currently within the historic lakebed boundary. Our study determined that managed retreat through the acquisition of properties across five regions totalled approximately $956 million. This represents less than half of the most expensive flood recovery options estimated by the City of Abbotsford, which range from $200 million to $2.4 billion in cost, and include infrastructure works such as upgrading the pump system and adding a narrow floodway for excess water. 

Our analysis is not intended to represent a complete account of the cost of reclaiming and revitalizing the lake, such as the incurred costs associated with lost revenue for farmers if their properties were purchased. Instead, we offer an alternative to the status quo by comparing recovery options proposed by local governments with a scenario of managed retreat that would allow Sumas Lake to return. This scenario draws upon Indigenous laws, knowledges, and decision-making, such as understanding the responsibility of Xólhmet te mekw stám ít kwelát/xáʔɬəmət ct mək̓ʷ ʔə kʷə swéʔs (‘we have to take care of everything that belongs to us’). Managed retreat represents an opportunity to further advance community and ecosystem resiliency in the Fraser Valley floodplain, which will be vulnerable to severe flooding under a rapidly changing climate. 

Citation

Finn, R. J., Ned-Kwilosintun, M., Ballantyne, L., Hamilton, I., Kwo, J., Seymour-Hourie, R., Walters, K.E. … & Martin, T. G. (2024). Reclaiming the Xhotsa: climate adaptation and ecosystem restoration via the return of Sumas Lake. Frontiers in Conservation Science, 5, 1380083. https://doi.org/10.3389/fcosc.2024.1380083.

Abstract

Sumas Lake (Xhotsa), located in the Fraser Valley, British Columbia, Canada, was the heart of Semá:th Nation Territory and the epicenter of a complex Indigenous food system. For the Semá:th people, the lake represented life and livelihood. In 1924, the lake was stolen and drained in an instance of land theft that occurred during a nationwide campaign of land dispossession and genocide, decimating an ecology that supported a rich and diverse Indigenous food system and replacing it with a settler food system. A century later, in November 2021 climate change induced flooding caused the lake to return, resulting in the evacuation of thousands of people and causing millions in damages to homes and infrastructure. Since the flood, the response has been a continuation of the status quo to protect settler agricultural lands via increased investment in hard structures that control the flow of water based on assumptions of the predictability of future flow conditions. We offer a missing narrative by bringing together an analysis of Indigenous laws and oral tradition with an assessment of the economic costs of “managed retreat”, defined as the purposeful relocation of people and infrastructure out of harm’s way. We find that the cost of buying out properties in the lakebed and allowing the lake to return is close to half the cost ($1 billion) of maintaining the status quo ($2.4 billion), while facilitating climate adaptation, and restoration of a floodplain ecosystem that supported thriving populations of people, salmon, sturgeon, ducks, and food and medicinal plants– including many species which are now endangered. Returning Sumas Lake by centering ‘Water Back’ as a climate resiliency solution, enacts both food systems and ecological reconciliation, addressing the harms caused by the loss of the lake to the Semá:th People that is still felt to this day. In a time when climate change induced flooding is predicted to increase, this study demonstrates how the inclusion of Indigenous laws and knowledges are critical to the development of solutions toward a more sustainable and just future.

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