HR: 1340h
AN: H13B-1336    [Abstracts]
TI: Regional Stream Temperature Response to a Severe Drought in Relation to Catchment Characteristics
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: Stahl, K
EM: kstahl@geog.ubc.ca
AF: Department of Geography, The University of British Columbia, 1984 West Mall, Vancouver, BC V6T 1Z2 Canada
AB: Stream temperatures generally reach their summer maxima during extended periods of hot, dry weather in association with low streamflow. However, glacier runoff tends to increase under these conditions and is hypothesized to be an effective regulator of summer stream temperature. This study draws upon synoptic surveys of continuous stream temperature records in tributaries of two mountainous drainages in British Columbia, Canada, during a severe drought period in summer 2004. Regression tree modelling revealed that the maximum weekly average temperature (MWAT) for the 2004 summer was, on average, approximately 4 deg C lower for streams draining catchments with more than 5% glacier cover, supporting the hypothesis that glaciers act as thermal regulators. For the catchments with low or no glacier cover, the model included splits based on estimated bankfull width and percentage lake cover, both of which had positive influences on MWAT. The inclusion of bankfull width is consistent with the decrease in shading by riparian forest with increasing stream width. The inclusion of lake cover could reflect the direct effects of lakes in generating high outlet stream temperatures due to summer stratification, but could also be a surrogate for other aspects of catchment morphology that influence stream warming.
DE: 1871 Surface water quality
DE: 1878 Water/energy interactions (0495)
SC: Hydrology [H]
MN: Fall Meeting 2005