Dust Mitigation and Monitoring Research for Williston Reservoir Beaches in British Columbia, Canada.

Williston Reservoir in northern British Columbia was created when BC Hydro constructed Bennett Dam on the Peace River in 1968 to generate hydroelectric power. Williston Reservoir is the largest body of freshwater in British Columbia with a surface area of 1775 km² and a shoreline of 1770 km.  The First Nation Tsay Keh band was forced to relocate to the north end of the reservoir as a result of the water impoundment.  When reservoir levels are at low pool in the spring, 10,000 ha of beach is exposed.  High winds of  > 20 km/h cause dust storms from exposed beaches that impacts visibility and air quality in Tsay Key village.  With funding and coordination by BC Hydro, we initiated a 3-yr field research project in 2008 to: (i) evaluate the effectiveness of two tillage practices to mitigate dust from beaches, and (ii) conduct regional dust monitoring at seven sites surrounding Williston Reservoir.  The tactic for the tillage is to bring silt-clay soil from the subsurface to the surface to provide durable roughness. The tillage experiment is located on Ominica Beach and covers 75 ha.  Treatments are: (i) tillage with twisted-point chisel with shanks spaced 1 m apart, (ii) tillage with a lister plow with lister blades spaced 1.3 m apart, and (iii) control.  Particulate emissions are measured using an array of Big Spring Number Eight (BSNE) samplers and numerous DustTrak aerosol monitors.  Each of the seven regional monitoring sites has a wide assortment of apparatus to monitor PM_2.5, PM₁₀, and total particulates on a 24 hr basis. An overview of the research project and data from the 2008 dust season will be presented.