Vulnerability of shallow ground water and drinking-water wells to nitrate in the United States: Model of predicted nitrate concentration in U.S. ground water used for drinking (simulation depth 50 meters) -- Input data set for drainageditch (gwava-dw_ddit)
This data set represents the area of National Resources
Inventory surface drainage, field ditch conservation practice,
in square kilometers, in the conterminous United States.
		
The data set was used as an input data layer for a national
model to predict nitrate concentration in ground water used for
drinking. …