Water Resources Research Act Program

Details for Project ID 2009AK75B

The diminishing role of glacier runoff into Eklutna Lake; potential impacts of hydropower and water supply for the Municipality of Anchorage

Institute: Alaska
Year Established: 2009 Start Date: 2009-03-01 End Date: 2010-02-28
Total Federal Funds: $19,514 Total Non-Federal Funds: $41,066

Principal Investigators: Michael Loso

Abstract: Anchorage, the largest city in Alaska, is critically dependent upon the waters of Eklutna Lake for both drinking water (~80% of the city’s supply) and hydropower generation (10-15% of the city’s supply). Eklutna Lake is glacier-fed, and existing work by APU faculty and students demonstrates that the Eklutna Glacier has retreated dramatically over the last 50 years, losing approximately 1.5 km3 of ice. Impacts of this ongoing glacier retreat include the short-term provision of additional meltwater to the Eklutna Lake, but over the longer term will likely include a reduced contribution of meltwater during the mid-summer when Municipal demand for water and power peaks. Additional glacier-mediated changes to the temperature and sediment load of the lake’s inlet stream appear to have already altered the density-driven stratification of the lake with implications for water treatment and reservoir volume. Here, I propose an expansion of existing research on the Eklutna Glacier and Eklutna River to assess the impacts of ongoing climatic changes on the glacier runoff contribution to Eklutna Lake. The existing research is a long-term, student-led glacier mass balance monitoring program initiated two years ago by Alaska Pacific University. The new work proposed here will be led by two new graduate students. One, focused on the glacier, will expand the mass balance and velocity measurement program to assess the nature and magnitude of the glacier’s response to expected climatic changes. The second student, focused on hydrology, will collect a time-series of water and sediment discharge on the glacier-fed West Fork Eklutna River and a comparable time-series from the predominantly non-glacial East Fork to predict the hydrological response to shrinkage of the Eklutna Glacier. Support is requested primarily for graduate student salary and logistical expenses and for acquisition of an additional stream monitoring station to augment the existing West Fork station; mentoring will be provided by research collaborators from Alaska Pacific University, US Geological Survey, the College of Charleston, the Anchorage Water and Wastewater Utility, and Municipal Light and Power.