Water Resources Research Act Program

Principal Investigators: Adam Clark

Abstract: Glacier National Park contains one of the largest concentrations of glaciers left in the Rocky Mountains of the United States (Key et al, 2002). Mountain glaciers have shown to be significant regulators of summertime stream flows because they continue to supply cold water after the winter snowpack has completely melted (Moore et al, 2009). In Glacier Park, and much of the American West the summer months are typically hot and dry. Glaciers can moderate the impacts of prolonged summer droughts due to the fact that glacier-fed streams are not relying on summer precipitation to maintain a certain discharge (Meier and Tangborn, 1961). The glaciers in Glacier National Park have been receding over the past 100 years (Johnson, 1980 and Carrara and McGimsey, 1981) and one model forecasts a total melt-out of all the Park's glaciers by 2030 (Hall and Fagre, 2003). The resultant decrease in cold water input from glacier runoff poses threats to the aquatic and riparian ecosystems that evolved in these glacier fed watersheds (Moore et al). In addition to the ecological effects, the loss of glacier meltwater discharge has implications for agricultural use and for agencies such as the Bonneville Power Administration (BPA). This federal agency, administers 31 federal hydroelectric projects in the Columbia River watershed. One of these includes Hungry Horse Dam, which is located 10-12 miles west of Glacier Park. Only two glaciers, Sperry and Grinnell, have been measured quantitatively for ablation (Johnson, 1980 and Reardon, 2008). A zero order estimate using an average melt rate obtained from Sperry Glacier and applying it to all the glaciers in Glacier Park reveals an annual, 100-day ablation season discharge of 9.5-7.5 m per second, or 330-270 ft per second. However, this back of the envelope calculation is not reliable because it is based entirely on a data set from only one glacier (Reardon, 2008). Recent research examining glacier mass changes in the North Cascade Mountains of Washington State indicate that a single representative glacier is difficult to choose without investigating others in the same geographic region (Fountain et al, 2009). No studies exist that examine the melt rate variability between glaciers in Glacier National Park. I propose one is needed in order to accurately quantify the total glacier meltwater discharge.