Wyoming Groundwater-Quality Monitoring Network

The Wyoming Groundwater-Quality Monitoring Network is a cooperative program with the Wyoming Department of Environmental Quality, begun in 2009 to establish baseline groundwater conditions in the state. Representatives from the U.S. Geological Survey, Wyoming Department of Environmental Quality, U.S. Environmental Protection Agency, Wyoming Water Development Office, Wyoming Geological Survey, and Wyoming State Engineer’s Office formed a steering committee, which meets periodically to evaluate progress and consider modifications to strengthen program objectives.

Ambient or baseline monitoring is being conducted in “priority” areas where groundwater has been identified as an important source of drinking water to public and private water supplies, is susceptible to contamination, and is overlain by one or multiple land-use activities that could negatively impact groundwater resources.

Groundwater samples were collected from 146 existing shallow (less than or equal to 500 feet deep) wells from November 2009 through September 2012. These randomly selected wells were a mix of domestic, stock, municipal, and monitoring wells. Samples were analyzed for a broad suite of inorganic and organic constituents. Several different laboratories capable of varying reporting levels and using dissimilar data formats performed the analyses.

Values of physical characteristics, major ions, trace elements, nutrients, radionuclides, volatile organic compounds, and coliform bacteria were compared to federal and state regulatory water standards. Major-ion chemistry was characterized for different hydrogeologic units. Stable isotopes of hydrogen and oxygen were compared to the Global Meteoric Water Line and Local Meteoric Water Lines.

Water-quality data are stored in the USGS National Water-Information system data base. Data are publicly available and are used by interested stakeholders to establish baseline groundwater-quality conditions to serve as a reference to which future groundwater-quality data can be compared. Well owners were notified of results exceeding federal or state regulatory water standards.