Lake Country has taken a close look at the impact the White Rock Lake wildfire had on water quality in Okanagan Lake

Wildfire and water quality

Lake Country officials have been keeping a close eye on water-quality risks in the wake of the 2021 White Rock Lake fire at the north end of Okanagan Lake.

In 2022, the District of Lake Country used a $30,000 grant from Okanagan Basin Water Board (OBWB) to study the impact of the 2021 White Rock Lake wildfire on source waters, in partnership with Larratt Aquatic Consultants.

“The upper watershed is one of the main sources of drinking water in the Okanagan. These upland waters also flow into valley-bottom lakes,” said Carolina Restrepo-Tamayo, OBWB Office and Grants Manager. “Polluting of these water sources has become a growing concern. Wildfires and extreme rains contribute to the problem, but so can backcountry activity, including recreation, mining, forestry, ranching and illegal dumping. Over time, a lot of the natural systems that would have historically cleaned and filtered water have been damaged, impacting water quality for people, but also fish and the larger ecosystem.”

The creeks originating in the affected watersheds will discharge nutrients, carbon and sediment that may have an immediate effect on water intakes in the north end of Okanagan Lake and a more gradual impact on the rest of the lake.

The study involves monitoring the water-quality impacts on the nutrient levels of the north part of Okanagan Lake through sampling. The study’s results will quantify water quality effects from the fire in a wildfire threat assessment report, enabling the formation of future actions.

“The 2021 White Rock Lake wildfire required the district to prioritize understanding the impacts the fire may have on the lake, surrounding communities, and our drinking water source. Lake Country citizens are very concerned about the quality of water for drinking and swimming. The wildfire burned over 85,000 hectares, including a large portion of the watershed for the north end of Okanagan Lake,” said Lake Country Mayor Blair Ireland. “The aim of this report is to determine how the effects of the wildfire, such as more severe freshet, runoff, erosion and sediment entering the lake will affect our source water quality.”

The report will be shared with other water suppliers at the north end of the lake including the Regional District of Central Okanagan, Regional District of North Okanagan and Okanagan Indian Band to encourage collaborative approaches to water management.

In addition to the report, a source protection plan was created, which serves as an update from the District of Lake Country Source Assessment of Okanagan Lake Intake published in 2010. This update re-evaluated hazards and vulnerabilities with the potential to affect the safety and sustainability of the district’s water supply, and recommends risk management actions to address them.

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