ANNUAL WATER BALANCE FOR THREE NESTED WATERSHEDS ON THE NORTH SLOPE OF ALASKA

Abstract

AlaskaOs North Slope is underlain by continuous permafrost with an active layer varying in thickness from 25 cm to greater than 100 cm. We have been collecting snowpack, runoff, precipitation and meteorological data at three nested watersheds: Imnavait Creek Watershed (2.2 km2), Upper Kuparuk Watershed (146 km2), and the entire Kuparuk River Basin (8140 km2). In 1993 we began collecting data for the Upper Kuparuk Watershed. Initially one precipitation gauge was located at this site. In spring 1996 five additional gauges were installed and we found considerable differences in precipitation across the watershed because of topography. We reconstructed the precipitation for 1993-1995 based on trends detected in the 1996-1997 data. From these data, we compare water balances at three different watershed scales between 1993 and 1997. During the ablation period, snowmelt-generated runoff dominates while evapotranspiration dominates during summer months, particularly in the low gradient coastal plain.