Ground water level measurements in selected boreholes near the site of the proposed repository

Analysis of twenty years of ground water level monitoring data by the Department of Energy on the boreholes comprising the periodic network near Yucca Mountain indicate that overall, such levels have been remarkably stable. Continuing this program of longterm monitoring, the Harry Reid Center for Environmental Studies at the University of Nevada - Las Vegas (HRC) has acquired quarterly data on water levels from the same network between July 2001 and June 2003. Analysis of selected 2002 quarterly ground water level data collected by the HRC using manual and electronic techniques on boreholes in the volcanic flow system aquifer appears to support this general concept of highly stable ground water levels. Similarly, water levels in the only borehole penetrating the carbonate aquifer also exhibited very small overall variability, as did 3 wells located in shallow alluvium. Under a new, seismically-related monitoring initiative developed by the HRC, water levels electronically measured at very high sampling rates in 2 volcanic flow system wells exhibited small, short-term fluctuations in response to an Alaska M7.9 earthquake that occurred in November 2002, nearly 2340 miles from Yucca Mountain