HYDROLOGICAL CHANGES IN THE SIERRA NEVADAS DUE TO LOSS IN GLACIERIZED AREA

Globally, glaciers are retreating as climate warms. Locally, the loss of glaciers may affect basin hydrology, which in turn affects municipal water supplies. We hypothesize that as glaciers shrink their catchments will have both higher and earlier peak discharges similar to differences, found in glacierized and non-glacierized catchments. However, the magnitude of these hydrological changes is unknown. This study is being done to show the change in glacier area and the hydrological affects over the past four decades in the Owens River catchment, eastern Sierra Nevadas, California. The Owens River catchment is important because the runoff from this catchment is captured and distributed to Los Angeles through the Los Angeles Aquaduct. In order to determine the change in glacierized area within the Owens River catchment, we first use recent aerial imagery in GIS (Geographical Information Systems) to inventory the extent of present ice. Current glacier extent can then be compared to an inventory of glaciers derived from aerial imagery in 1972 by the USGS. The differences between the two inventories of glaciers can quantify the change in glacierized area in the Owens River catchment. Once the change in glacier area is determined we examine its affect on the hydrology by comparing USGS discharge data from the period of the first glacier inventory to discharge data from our recent glacier inventory.