Water Turbidity Risk from ORV Traffic in Okanagan Watersheds

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University of British Columbia

Project Description:

The proposed project is part of a larger initiative to understand and mitigate the risk to water quality in source water streams due to multi-use activities that take place on Crown lands. Included in this activity mix are: (1) forestry operations and road maintenance; (2) cattle grazing; and (3) recreational use by humans (e.g., camping, fishing, hiking). Although a great deal is known about deleterious impacts due to the first two categories of activity, accompanied by a range of recommended best management practices (BMPs) that have been implemented by the respective industries, there remains great uncertainty with regard to the human recreational impact as well as the cumulative effects. The proposed project will examine one component of this complex process—the effect that Off-Road Vehicle (ORV) traffic may be having on suspending streambed sediments (measured as increased turbidity levels) in streams as a consequence of instream crossings.

The project will provide useful information on the following aspects of the management challenge: (1) estimates of the intensity of ORV traffic in two sub-watersheds in the Okanagan region; (2) the frequency and timing of stream crossing by ORVs and other motorized vehicles at several heavily utilized trails; (3) measurements of suspended sediment concentrations in turbidity plumes that arise because of ORV crossings; (4) estimates of plume dispersion and downstream travel times, to points where the turbidity levels fall below the Canadian Drinking Water Guidelines; and (5) an assessment of the relative risk to drinking wate quality with regard to sediment turbidity.

The specific sub-watersheds to be monitored will depend on a range of logistical considerations such as ease of access, intensity of use, and representativeness, but initial discussions with staff at FLNRO and RDNO indicate a preference for either Duteau or King Edward in the RDNO area with a likely continuation of monitoring in Postill in the RDCO area. Further discussions and field reconnaissance will be undertaken in the early spring when better access to potential sites is available.

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