Ground-water data for 1990--91 and ground-water withdrawals for 1951--91, Nevada Test Site and vicinity, Nye County, Nevada

This report presents selected ground-water data collected from wells and test holes at and in the vicinity of the Nevada Test Site. Depth-to-water measurements were made at 74 sites at and in the vicinity of the Nevada Test Site during water years 1990--91. Measured depths to water ranged from 301 to 2,215 feet below land surface and measured altitudes of the ground-water surface at the Nevada Test Site ranged from 2,091 to 6,083 feet above sea level. Depth-to-water measurements were obtained by a combination of wire-line, electric-tape, iron-horse, and steel-tape methods. Available historic withdrawal and depth-to-water data for ground-water supply wells have been included to show changes through time. Water samples were collected and analyzed for tritium concentrations at 15 sites during water years 1990--91. Tritium concentrations in bailed water samples ranged from below detection limits to 5,550,000 picocuries per liter. Tritium concentrations in samples from three wells exceeded drinking water standards established by the US Environmental Protection Agency. All three wells are separate piezometers contained within a single test hole near an area of extensive underground nuclear testing