Vulnerability of shallow ground water and drinking-water wells
to nitrate in the United States: Model of predicted nitrate
concentration in shallow, recently recharged ground water --
Input data set for population density (gwava-s_popd)
This data set represents 1990 block group population density, in
people per square kilometer, in the conterminous United States.
The data set was used as an input data layer for a national
model to predict nitrate concentration in shallow ground water.
Nolan and Hitt (2006) developed two national models to predict …