Environmental Management/Underground Test Area,
Nevada National Security Site

Underground testing of nuclear weapons at the Nevada National Security Site (NNSS) has created potential environmental hazards. The U.S. Department of Energy (DOE) National Nuclear Security Administration Nevada Site Office is concerned about these hazards and is committed to comply with existing environmental laws and regulations. In this regard, DOE established and manages the Underground Test Area (UGTA) as part of the Environmental Management (EM) program, which is tasked with performing corrective actions for inactive contaminated sites and facilities in Nevada where nuclear tests and weapons experiments have been conducted. The UGTA goals are to identify risks where radiological contamination may exist in groundwater as a result of underground nuclear tests, predict the movement of potentially contaminated groundwater, and define the contaminant boundaries or extent of migration of the radionuclides released during testing.

The U.S. Geological Survey (USGS) provides hydrologic expertise and technical guidance to DOE in support of the UGTA program, primarily on activities related to the characterization of the groundwater flow system. Principal USGS objectives for this program are to:

• Collect, compile, store, and report hydrologic data used in determining the local and regional hydrogeologic conditions in and around the NNSS.
• Complete, interpret, and analyze aquifer tests to support an increased knowledge of groundwater flow paths and travel times, which help develop accurate predictions of radionuclide transport.
• Estimate groundwater flow areas that can be used as boundaries or limits for flow budgets.
• Update a flow conceptualization to support modeling activities to include detailed water-level maps.
• Update a regional groundwater flow model.
• Support the USGS, NNSS Core Library & Data Center (CLDC), which is a repository for more than two million linear feet of core and cuttings collected mostly from the NNSS.