Use of the National Ground-Water Monitoring Network to Evaluate Selected Transboundary Aquifer Systems

Transboundary aquifer systems, by definition, cross a political boundary. The boundary may be international—but also can be a state or county boundary. Evaluation of aquifer conditions in transboundary aquifers often is time consuming because these data typically are in different data systems. Scientists and engineers must gather the data, assure data quality, and convert the measurements to a common datum prior to analysis. The National Ground-Water Monitoring Network (NGWMN) provides access to data of known quality in a common format, from disparate federal and state data systems transparently

The power of this capability is demonstrated by analyzing water-level data from three transboundary aquifer systems. First, water-level declines in the Lower Tertiary aquifer system (Montana/North Dakota/South Dakota) are presented. There are increasing demands on the aquifer system to support the water use necessary for increased energy production. Second, water-level declines in the Rio Grande aquifer system (New Mexico/Texas) are evaluated. Competing demands among these states and Mexico have resulted in water-level declines and subsequent lawsuits. Analysis of these data illustrates that the NGWMN provides a single, consistent dataset from which to evaluate the status of the nation’s aquifers and shared interstate groundwater resources. Because the NGWNMN and Canada’s Groundwater Information System adhere to international data-exchange standards, these same comparisons can be done across the U.S./Canada border. Analysis of selected transboundary aquifers between the United States and Canada also will be presented.