ABSTRACT: Glacial control of water resource and related environmental responses to climatic warming: empirical analysis using historical streamflow data from northwestern Canada.

CGRG Bibliography of Canadian Geomorphology
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Abstract

We applied nonparametric statistical techniques to historical streamflow datafrom five glacierized and four nonglacierized watersheds in southwest Yukonand northwestern British Columbia,Canada,to determine whether rivers withand without catchment glacial cover respond in significantly different ways to awarming climate.The analysis was posed in terms of contrasts between the two groups with respect to long –term trends in annual time series of total river flow volume. We found that glacier–fed rivers grew larger and nival streams progressively smal ler over the historical record under an obser ved regional warming trend. Although some of these trend effects are subtle,the overal l result was statistically significant at restrictive confidence levels.Combined consideration of hydrological, meteorological and glaciological trends suggests that the streamflow consequences of increasing temperature exceed those from a concurrent rise in precipitation in the study area,causing increases in both glacial melt water production and evapotranspiration;the former appears to have the dominant net hydrologic effect in glacierized catchments,and the latter in glacier–free watersheds.By empirically demonstrating that catchment glacial cover can result in opposite trends in total annual flow volume from river to river within an other wise hydroclimatologically uniform area,the analysis presents strong evidence that climatic warming can materially affect downstream water resources specifically via glaciological pathways, and also implies that regional generalizations of interpreted or projected hydrologic trends may not be tenable in variably–glacierized regions.

Bibliography of Canadian Geomorphology