SNOWSHED CONTRIBUTIONS TO THE NOOKSACK RIVER WATERSHED, NORTH CASCADES RANGE, WASHINGTON*

Authors


  • *

    Thanks to Donald Friend, Eugene Hoerauf, Paul Starrs and the Geographical Review editorial staff, and three anonymous referees for critically reviewing the manuscript. My research was supported by the Western Washington University Bureau for Faculty Research and the Human Fund. Thanks to Janet Collins, Jon Riedel, Mauri Pelto, my family, and everyone else who helped out on the project.

Abstract

ABSTRACT. Meltwater contributes to watershed hydrology by increasing summer discharge, delaying the peak spring runoff, and decreasing variability in runoff. High-elevation snowshed meltwater, including glacier-derived input, provides an estimated 26.9 percent of summer streamflow (ranging annually from 16 to 40 percent) in the Nooksack River Basin above the town of Deming, Washington, in the North Cascades Range. The Nooksack is a major spawning river for salmon and once was important for commercial, recreational, and tribal fishing, and in the past its flow met the demands of both human and aquatic ecosystems. But the river is already legally overallocated, and demand is rising in response to the rapidly growing human population. Variability in snowshed contributions to the watershed is considerable but has increased from an average of 25.2 percent in the 1940s to an average of 30.8 percent in the 1990s. Overall stream discharge shows no significant increase, suggesting that the glaciers are melting, and/or precipitation levels (or other hydrologic factors) are decreasing at about the same rate. If glaciers continue to recede, they may disappear permanently from the Cascades. If that occurs, their summer contribution to surface-water supplies will cease, and water-management policies will need drastic revision.

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