Categorical Exclusion Determination
Office of NEPA Policy and Compliance
June 28, 2016
Estimated Read Time min
The U.S. Geological Survey (USGS) needs geologic, stratigraphic, and hydraulic data for the purpose of characterizing groundwater flow and water quality in the eastern Snake River Plain aquifer. Monitoring wells are constructed to obtain the needed data, and the USGS has identified the need for an additional monitoring well. The proposed well is needed to provide coverage for information gaps related to regional geologic stratigraphy and groundwater flow by providing water quality information for the movement of a potential nitrate plume derived from old mercury ponds south of the Central Facilities Area (CFA) and to better track tritium movement from the Idaho Nuclear Technology and Engineering Center (INTEC). Waste Area Group monitoring at CFA has indicated a local groundwater flow path moving to the southeast from CFA, and the proposed new well location would help verify the hydrology of the area. The proposed action would continuously core geotechnical borehole USGS-144 to a depth of about 1,000 ft below land surface.