Sylix Okanagan Flood and Debris Flow Risk Assessment

In 2018, the Okanagan Nation Alliance (ONA), led the Sylix Okanagan Flood and Debris Flow Risk Assessment after recognizing a lack of a basin-wide approach to flood risk management. In 2017, the Sylix Okanagan territory was impacted by extreme flooding which threatened the community and ecosystem health. The goal of the project was to better understand flood and debris flow risk within the Okanagan- Similkameen basin and, in turn, inform risk mitigation activities. Flood risk is a growing concern across all of British Columbia as a result of heavier precipitation, rising sea levels, and warming temperatures. The impacts to health are wide-ranging, including: stress-related mental health outcomes, food and water insecurity, damage to key infrastructure and barriers to access key services. The project area includes the Okanagan River watershed including kɬúsxňítk (Okanagan Lake) and the nməlqaytkw (Similkameen River tributary) watershed. The region’s climate and landscape is diverse, and ranges from semi-arid grasslands to open pine forests. The region is one of the most biodiverse in Canada, and is a geographic link between more northern and southern ecosystems for many animals. The Syilx people have inhabited the interior plateau since time immemorial, and the project area is located on unceded territory. Today, the project area exceeds 360,000 people who live in six Syilx communities and over 15 primarily non-Syilx communities. As well, the project took an integrated approach to risk management, combining Syilx land-based knowledge on water from Syilx knowledge keepers with western watershed management practices. The project’s objectives were:

  • Better understand flood and debris flows and how they impact the region
  • Apply diverse perspectives in assessing the risk from these natural phenomena.
  • Collaborate with local governments to strengthen and align risk assessment initiatives.


Identifying Actions

In March 2018, the Okanagan Nation Alliance’s (ONA) Chiefs Executive Council (CEC) gave a directive through Tribal Council Resolution 372 for the Natural Resources department to complete a flood risk assessment, floodplain mapping, and an emergency response approach for the Nation. This includes a need to find solutions on how we may collectively better live with t̓ik̓t (flooding) and have a coordinated approach to emergency response. By developing an Okanagan-basin (including the Similkameen watershed) risk assessment, the Nation can be proactive, and make risk-based decisions regarding their territory and communities, and determine what priority measures can be taken, if possible, to improve safety, reduce, or even negate, the effects of flooding events. The actions identified to achieve this objective are: 1) Forming a flood steering committee, with representation from local governments and Syilx Okanagan Nation member communities, 2) Exploring local perspectives on the impacts of flooding through workshops, impact mapping, storytelling, etc., and 3) Scoring risk on a watershed scale through exposure and hazard mapping, hazard modelling, etc. The project was funded by the National Disaster Mitigation Program (NDMP) and completed from September 2018 to December 2019. Compared to typical risk assessments focused on western science methods, the approach for this project needed to evolve to incorporate Syilx Okanagan perspectives throughout the process. Looking toward the inner layer of the risk assessment approach, mapping is critical to the risk assessment process as it provides a mix of qualitative and quantitative information in a spatial context. This project distinguishes impacts as stemming from qualitative information, whereas consequences stem from quantitative information.


This project’s objective is to understand the risk due to t̓ik̓t and debris flows within the Okanagan and Similkameen Basin in order to support flood risk mitigation planning. To achieve the project objectives, activities supporting the risk assessment ranged across the spectrum of qualitative and quantitative to widen the sources of information and interpretation. Some example project activities and their purpose are explained below:

  • Watershed tours (mostly qualitative): Provided participants with an opportunity to experience the land from the perspective of Syilx Elders in specific areas.
  • Impacts mapping (mix of qualitative and quantitative): Enabled participants to share their knowledge and experiences by marking-up maps with flood and debris flow areas.
  • Workshops (mix of qualitative and quantitative): Focused on building relationships among people and organizations in the region while sharing relevant information.
  • Risk matrices (quantitative): Compared the risk from flood and debris flows in the Okanagan and Similkameen watersheds in terms of the magnitude and the consequences of the event.

In 2018-19, the initial phase of a multi-year flooding adaptation initiative was completed. The Federal Government’s National Disaster Mitigation Program (NDMP) was set up to reduce the risks and impacts of flooding on citizens. This program is administered on behalf of the Province by the Disaster Mitigation Branch of Emergency Management BC. Engagement of community leaders was also a key aspect of the project. This involved land-based learning, completing watershed tours with Syilx knowledge Keepers and elders. ONA contracted Ebbwater Consulting with their flood management and engineering experts to carry out the Risk Assessment, with direction from Syilx knowledge keepers. A Risk Assessment is a process to determine the nature and extent of risk, as well what are the potential impacts of future flooding events. This will support the Nation to be proactive in flood planning, guide mitigation solutions and for emergency management.

Outcomes and Monitoring Progress

A range of impacts were explored in the risk assessment, including: risks to the environment, affected people, culture, mortality, economics, and disruption. This was done through combined quantitative and qualitative activities, which produced a comprehensive synthesis of findings and a list of recommendations. The work advanced relationship building and co-learning between Indigenous and non-Indigenous partners in ecosystem-based management. The project participants engaged in a water-based visioning exercise to think about how to address key issues to adapt by becoming more resilient. This created a more holistic and well-rounded understanding of a complex problem. The outcomes of some of the key actions of the project are:

  • Better understand flood and debris flows and how they impact the region. Qualitative and spatially consistent quantitative information sources were used to obtain a rich database of knowledge. Both types of information were mapped.
  • Apply Syilx Okanagan perspectives to assess the risk from these natural phenomena. Throughout the process, discussions were led by Syilx Okanagan Elders. These perspectives were woven with multi- disciplinary western science to establish ecosystem-based guiding principles for adaptation actions.
  • Collaborate with local governments to strengthen and align risk assessment initiatives. By applying a consistent approach across the region, this project’s findings can be used to inform initiatives occurring in more local contexts. One of the project’s findings is that the recurrence of small flood events over time may be a greater risk compared to large flood events depending on how the assets are valued from one community to another.
  • Provide supporting information for future funding and to prioritize adaptation actions. The regulatory context is changing rapidly in BC related to Sendai, UNDRIP, Emergency Program Act, etc. The results from this risk assessment enable the ONA and regional partners to target more detailed information gathering, to align with Provincial and Federal programs, and to prioritize efforts within the Okanagan-Similkameen region.

Next Steps

This risk assessment project is part of a longer-term Syilx Okanagan t̓ik̓t (flood) adaptation initiative. The initiative is driven by Syilx perspectives, which include understanding the lived experience of the Syilx people through colonization. The Syilx Okanagan Nation fully believes that Indigenous knowledge is the way forward for climate change adaptation and complex water and land issues. This starts with treating siwɬkw (water) with honour, respect, and reciprocity to ensure that water is healthy for the tmixw (all living things). For these reasons, Syilx leadership needs to be at the forefront of planning, protection, and operational processes including the next steps of this risk assessment. Long-term actions will require relationships to be strengthened to build trust among people and organizations that have not typically worked together. This requires “breaking down silos” between, and even within, larger organizations in the public and private sectors. The remaining actions have been grouped according to the four priorities as follows: 1) Understanding Disaster Risk, 2) Strengthening Disaster Risk Governance, 3) Investing in Disaster Risk Reduction for Resilience, and 4) Enhancing Preparedness for Response.


Link to Full Case Study

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