Analysis of water-level data in the Yucca Mountain area, Nevada, 1985--95

Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

“…Therefore, the water levels used to construct the potentiometric surface for the site-scale model must, to the extent allowed by data availability, represent conditions consistent with the regional model that used water-level data (altitudes) representing the early 1990s. Water levels in boreholes located at Yucca Mountain generally have not fluctuated by more than one meter during the time period from 1985 until 1995 (Graves et al 1997). Some of the boreholes used in this analysis had no or very few water-level measurements taken during the 1980s and 1990s (Attachment I, Tables 1-2 and 1-4).…”

“…New data that were considered for use in this analysis were evaluated for validity and documented in scientific notebook SN-USGS-SCI-126-V1 (Tucci 2001), and the reasons for considering these new data to be invalid are described as follows. Based on observations of water-level data at Yucca Mountain, water levels generally fluctuate less than 1 m, and more often, less than 0.5 m (Graves et al 1997). Exceptions occur if a nearby well is pumped or if water levels are affected by seismic events.…”

“…Fred Cobb well: Basically similar arguments apply as for the Lewis Earliest Year of Measurementnatest Year of Measurement The earliest and latest year of reported measurement used in the calculation of the mean was determined and recorded. The data tabulated by Graves et al (1997) were not checked for earlier or later measurements. The data reported in Graves et al (1 997) were collected for the water-level monitoring studies being conducted as part of Yucca Mountain site characterization activities and, as such, were collected after 1986 under an approved quality assurance program.…”