HR: 14:20h
AN: H32D-03    [PDF]
TI: Headwater Stream Temperature Response to Forest Harvesting in Coastal British Columbia, Canada: Influences of Riparian Buffer Width, Channel Morphology and Weather
AU: * Moore, R (
EM: rdmoore@geog.ubc.ca
AF: Department of Geography, The University of British Columbia 1984 West Mall, Vancouver, BC V6T 1Z2 Canada
AU: * Moore, R (
EM: rdmoore@geog.ubc.ca
AF: Department of Forest Resources Management, The University of British Columbia 2424 Main Mall, Vancouver, BC V6T 1Z4 Canada
AU: Gomi, T
EM: gomi@interchange.ubc.ca
AF: Department of Geography, The University of British Columbia 1984 West Mall, Vancouver, BC V6T 1Z2 Canada
AU: Dhakal, A
EM: Dhakal@interchange.ubc.ca
AF: Department of Forest Resources Management, The University of British Columbia 2424 Main Mall, Vancouver, BC V6T 1Z4 Canada
AB: Forest harvesting can influence stream temperature regimes, and the potentially deleterious impacts of higher temperatures on salmonids and other species have generated significant debate. One common approach to protecting streams is to leave a riparian buffer to provide shade. However, little information has been collected on the effectiveness of different buffer widths. We report the results of a 6-year field experiment to evaluate the effects of different riparian buffer widths on stream and riparian ecosystems, including stream temperature response, in headwater streams in coastal British Columbia. The experiment included 13 streams, with at least three being assigned to each of four treatments, including no harvesting (80 yr-old second growth conifer riparian forest), clear-cut harvesting with 10 m and 30 m riparian buffers, and clear-cut harvesting with no buffer. Regression analysis was used to calibrate the pre-harvest data for each treatment stream with one of the control streams, to provide a basis for estimating post-harvest treatment effects. Autoregressive and heteroskedastic errors were included in the regression model, because stream temperature exhibited serial correlation and the error variance increased with stream temperature. Temperature response was substantial in the clearcut treatments with no buffers, with maximum temperatures increasing by up to 8 degrees C. The magnitude of temperature response amongst the no-buffer treatments varied with channel morphology, particularly in relation to bank shading and stream depth. The treatment effect for daily maximum water temperature increased with decreasing flow and increasing maximum air temperature on the current day, and also exhibited significant autocorrelation, indicating that the sequence of daily weather conditions can influence the magnitude of temperature response.
DE: 1719 Hydrology
DE: 1803 Anthropogenic effects
DE: 1871 Surface water quality
DE: 1878 Water/energy interactions
SC: Hydrology [H]
MN: 2003 Fall Meeting