DELEGATION to Okanagan Basin Water Board
Shaun Reimer, Section Head – Public Safety and Protection Ministry of Forests, Lands, Natural Resource Operations, and Rural Development
Considerations for Changes to the Okanagan Lake Regulation System (OLRS)
Dr. Anna Warwick Sears introduced Mr. Reimer and noted that his presentation is the result of a request from Peachland Council to discuss Okanagan Lake management levels.
Mr. Reimer provided some background for how the current regulations were set. He also gave an overview of lake levels since 2017 and the issue of flooding, noting how conditions have been different each year and how the Okanagan is experiencing increased hydrologic variability.
Decisions to release water downstream are proactive since only so much can be released at a time to prevent flooding downstream. At the same time, consideration is given to ensuring enough water to meet agricultural and domestic irrigation needs in summer. Other issues that are considered when releasing water is the impact on kokanee, ensuring eggs are not scoured out of the gravel in spring, and that there is enough water for fry emergence and shore spawning in fall.
Okanagan sockeye are also considered. It has been difficult to manage for this, Mr. Reimer said. It is recognized that the OLRS has to change and hopefully, by working with the OBWB, Okanagan Nation Alliance, local and senior governments and other partners, we can address it, he added.
However, it’s important to understand that any changes could have negative consequences for one of these interests. Other considerations are the impact on the Rocky Mountain Ridged Mussel, and Chinook salmon which are currently under review for possible listing under the Species at Risk Act.
The next step would be to do a gap analysis to determine the information needed to develop new OLRS targets. The original targets were developed as part of a consultative process and this would be required again to change them, Mr. Reimer added.
In response – an update to the OLRS, Mr. Reimer suggested that perhaps a study should be conducted on expanding the channel downstream into the USA. This would have to include land acquisition to address downstream flood concerns, and would allow for a more reactive (rather than proactive) approach. Managing the lake as is done now, responding proactively and releasing water based on what inflow is expected, can cause issues in the case of a multi-year drought. A recent flood management report conducted for the OBWB by Northwest Hydraulic Consultants didn’t speak to the increased risk for drought extremes with climate change.
Asked about the potential to capture and hold water in upland reservoirs, he explained that Okanagan Lake is best for providing a large stable water supply. Dr. Sears added that a preliminary report by the Water Stewardship Council’s Dams and Reservoirs Committee suggests that increasing upland reservoir capacity would not be significant enough to help with flood control of mainstem lakes.
Director Bob Hrasko – Water Supply Association of BC -who chairs the committee- added there are several issues with the idea of using upland reservoirs, including that there is no way to control levels from uphill, they freeze, they are hard to get to in winter to monitor and maintain, they can fill quickly.
When asked, Mr. Reimer responded that more stream and snow monitoring would be useful. Dr. Sears suggested that the OBWB could write a letter to province later in November, after the provincial election, recommending that there be a review of the OLRS.