Statistical models of nitrate occurrence in the glacial aquifer system of the northern United States, developed by the U.S. Geological Survey, use observed relations between nitrate concentrations and sets of explanatory variables?representing well-con
Walter, Donald A. dawalter@usgs.gov,Starn, J. Jeffrey. The use of process models to inform and improve statistical models of nitrate occurrence, Great Miami River Basin, southwestern Ohio. 2013-01-01.