The San Jose Watershed

The watershed’s main river, the San Jose river, flows northwest from Lac La Hache to Williams Lake, in British Columbia’s Central-Cariboo region. The river’s main tributaries include Borland Creek, Jones Creek, and Knife Creek.

Issue at Hand:

Water supply in the San Jose watershed is already heavily allocated. Potential impacts of climate change are locally unknown but are likely to cause an increase in mean annual temperature and change the amount and distribution of precipitation through the year.  The City of Williams Lake has recognized the critical problem that over-allocation of the aquifer will cause over time, and significant conservation efforts are now underway, as are hydrological studies of the aquifer. 

Land managers are seeking insights into the impacts of climate change on the landscapes of the Cariboo Chilcotin, and direction on deployment of limited resources within the watershed. In particular, three interacting phenomena are taking place that may have cumulative impacts on the water supply: First, mountain pine bark beetle has killed a significant component of the trees over fairly large areas in the upper reaches of the San Jose Watershed.  Reduction in interception and transpiration losses, coupled with salvage impacts on water retention and run-off, will have potentially positive impacts on surface run-off and recruitment to ground water. Second, Dry Douglas-fir forests that cover the lower reaches of the watershed have had little disturbance over the past 40 years, and the canopy of those forests is closed, leading to over-dense forests, increased interception of precipitation, and increasing forest health problems.  These influences may cause negative pressure on surface run-off and recruitment to ground water. Third, climate change is expected to impact forest dynamics and water flow.

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