8°
8°
Flood Mitigation Strategies
Keremeos is a municipality within the Similkameen Valley and much of the community lies within the floodplain of the Similkameen River. The November 2021 atmospheric river event was the largest flood on record (55-years) and highlighted the fact that peak flows can occur along the Similkameen river at Keremeos outside the typical freshet season.
Recent analysis within the region shows that the likely frequency of flood events is increasing, which includes the Village of Keremeos and surrounding area. When you combine this with Pacific Climate Impacts Consortium (PCIC) data which suggests atmospheric river events are expected to increase into the future, the future impact of these events needs to be better understood throughout the region and for the Village, within the downstream reaches of the Similkameen River at Keremeos.
Keremeos was successful in securing multiple funding streams of the Community Emergency Preparedness Fund (CEPF) Disaster Risk Reduction – Climate Adaptation. This resulted in the following work being completed:
The November 2021 flood event prompted the Village to secure additional CEPF funding to update the Flood Hazard Mapping and Flood Mitigation Plan.
Initial phases of this flood mitigation update project began in March 2023 and involved the preparation of a flood risk assessment and floodplain mapping exercise, which were completed in December, 2023. Building on this work, several flood mitigation strategies have been developed based on the information collected and analyzed thus far.
Flood Mitigation Strategies Open House
As part of this work, an open house was held on June, 2024 to present several flood mitigation strategies to the community to raise awareness of the project and answer questions. More information and resources are included below.
Available Open House Materials
Flood Mitigation Strategies Poster Boards
Flood Mitigation Strategies Presentation
Frequently Asked Questions
Q. Can we dredge the river?
A. Obtaining approval for dredging is a very difficult process due to many competing interests (such as environmental protection of streams). There is also significant maintenance required as debris will begin to fill back into the river due to natural river processes. This is not an effective flood mitigation strategy as the models do not show a significant reduction in flooding.
Q. Can a dam be built upstream?
A. There are people asking whether a flood control dam can be built in the upper watershed. It is very complicated to build a dam, with rigorous approval processes, as we have seen with the approval of Site C dam which took 40 years.
Q. What flood depths would we experience in the Village during a flood event?
A. 1 to 3 meters depending on the location of flooding, location of dikes, and climate change.
Q. Wouldn’t we want to protect Highway 3?
A. Diking along 10th Avenue is currently the best option to protect Highway 3 as a transportation corridor. There are some complications/nuances, but these can be worked through. This is a potential option, but not necessarily the recommended option.
Q. If we dike along Boundary Road, can Highway 3 be raised?
A. The highway falls under the jurisdiction of the Ministry of Transportation and Infrastructure (MoTI) who are looking at this as an option for several highways which are at risk for flooding. They have updated their design criteria and methods, but timelines are unknown as larger transportation corridors are being reviewed first (e.g. Highway 5 and Highway 8 which was severely impacted in 2021).
Q. What is the elevation of 10th Avenue now, and what would be the elevation if it was modified?
A. It varies along its terrain and would follow the grade of the river. We would need to build most of the alignment up by approximately 2.5 meters. It would be a big mound and taller than what it is now.
Q. If the Boundary Road dike was installed, what would happen to the river confluence?
A. The dike would not come in at a 90-degree angle, leaving a small natural wetland feature. This would allow a bit more room for water to stagnate at this confluence.
Q. How would the dike tie into Boundary Road at Highway 3?
A. The road tie ins would get quite long. The proper vertical curves would need to be developed to ensure that a ramp isn’t created. The tie ins and geometry of this would be more complicated than a dike along 10th Avenue.
Q. What is the downside of using the Similkameen rail trail as the site of the dike instead of 10th Avenue?
A. The main reason 10th Avenue was chosen is because it protects more properties. It’s wide enough, is public land, and there is a bit more room with the right-of-way. We will look at those other alignments as we get into the detailed designed process, and the rail trail is also an option.
Q. Can flood gates be installed to reduce flooding?
A. There is an option to create flood gates but in this context they would need to be 100 meters wide to effectively let the water out. We could design a system with flood gates, but it becomes much more expensive.
Q. If we build a setback dike on 10th Avenue (and the orphaned dike remained in place), is there any compensation available for those who would still be flooded?
A. These properties are already at flood risk. You would want to build elements into the house to be more flood resilient and recover from floods faster, such as solid insulation and concrete instead of drywall. These properties would need to plan for flooding as there is not a realistic option to stop this area from flooding.
Q. Are there any interim measures for support of the existing orphaned dike?
A. There is very little that can be done. Orphaned dikes are in a legal limbo, if someone does work to it, you become responsible. There are no funding programs to do upgrades. Orphaned dikes are regulated under the dike maintenance act, so even if one is on your property, you cannot legally touch it (there needs to be a diking authority to do any work on them). The province will not authorize any changes to a dike unless it has a proper long term maintenance plan. However, under extreme situations someone could probably go in to protect the public.
Flood Hub Resource Library
Historical documents pertaining to flooding analysis, mapping and mitigation effecting the Village of Keremeos and Similkameen River have been complied for reference purposes. Click on the links below to access the various reports/studies/map.
Village of Keremeos Similkameen River Flood Mitigation Plan | Ecora (March 2021)
Flood Hazard Mapping for the Similkameen River | Ecora (March 2021)
Flood Risk Assessment of the Similkameen River | Ecora / Dobson Engineering (December 2020)