Yucca Mountain Oversight
Walker Lake's future as a viable fishery has been seriously threatened over the last one hundred years or so due to insufficient inflows from the Walker River. From data covering the 1939-1993 period of record, the U.S. Geological Survey (USGS) estimated that an average of 76,000 acre-feet per year flowed into the lake from the Walker River. However, due to the highly variable hydrology of this region, the Walker River has rarely produced "average" inflows to Walker Lake. As an example, during the recent ten-year period of 1987-1996, which encompassed the eight-year drought period of 1987-1996, Walker Lake received inflows from the Walker River in essentially only three years (1987, 1995, and 1996). Nonetheless, under such "average" hydrologic conditions, in addition to Walker River inflows, the USGS estimated that Walker Lake might expect to receive an average of 14,000 acre-feet per year of lake surface precipitation (4.9 inches per year), 11,000 acre-feet per year of local ground water inflows, and 3,000 acre-feet per year of local surface water inflows. More than off-setting these inflows into Walker Lake, however, has been a rate of lake surface evaporation totaling approximately 137,000 acre-feet per year (4.1 feet per year), thereby producing a water budget deficit for Walker Lake of approximately 33,000 acre-feet per year over the 1939-1993 study period. With the exception of the 1997- 98 winter, water flows into Walker Lake have been relatively small.
