Approaching four decades of forest watershed research at Upper Penticton Creek,British Columbia: A synthesis |
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| Authors: | Rita D Winkler Diana M Allen Tim R Giles Brian A Heise R Dan Moore Todd E Redding Dave L Spittlehouse Xiaohua Wei |
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| Institution: | 1. Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Kamloops, British Columbia, Canada;2. Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada;3. Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, British Columbia, Canada;4. Department of Geography, University of British Columbia, Vancouver, British Columbia, Canada;5. Department of Geography & Earth and Environmental Science, Okanagan College, Penticton, British Columbia, Canada;6. Ministry of Forests, Lands, Natural Resource Operations and Rural Development, Victoria, British Columbia, Canada;7. Department of Earth, Environmental and Geographic Sciences, University of British Columbia, Kelowna, British Columbia, Canada |
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| Abstract: | Over the past 35 years, the Upper Penticton Creek (UPC) Watershed Experiment has supported forest hydrology research in south-central British Columbia (BC), Canada. This paper provides a synthesis of research results, highlights the challenges facing UPC and identifies new research directions. Clearcutting approximately 50% of two small, snow-dominated (Dfb Koppen classification) watersheds advanced the timing of snowmelt-generated high flows and decreased late-summer low flows, relative to predictions based on pre-treatment regressions. Changes in high flows did not have a significant effect on stream channels due to low stream power, coarse substrate, and limited riparian disturbance. Changes in summer low flows reduced modelled useable fish habitat by 20%–50%. Evaporation averaged 52% of the annual precipitation in the mature forest, was reduced to 30% in a clearcut, and recovered to 40% and 47% in a 10 and 25 year-old stand, respectively. Groundwater recharge to the bedrock was estimated at 19% of annual precipitation, indicating that, even with the large uncertainty associated with this estimate, deep groundwater should not be ignored in the water balance. Suspended sediment, turbidity, and colour increased post-logging; however, chemical surface water quality did not change. Aquatic community structure changed post-logging; and although this affected the processing of organic matter, the effects on habitat quality were considered minimal. The information gained at UPC has supported provincial policies, management guidelines, forest stewardship plans and watershed risk assessments. The undisturbed control watershed, re-growing treatment watersheds and ongoing long-term hydrometric monitoring continue to provide opportunities for future research addressing issues such as the effects of young forests on streamflow and hydrologic recovery, and the influence of climate change on the hydrologic regime. |
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| Keywords: | aquatic ecology forests groundwater hydrologic recovery logging paired watershed experiment snowmelt streamflow |
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