Targeting Animal Waste Pollution Potential Using a Geographic Information System

Data on livestock operations were added as a data layer and corresponding attribute table to the Virginia Geographic Information System (VirGIS) for seven counties in Virginia. A simple model calculates an animal waste pollution index (AWPI) which rates each site based on waste load, slope, and distance-to-stream. These factors are considered both for the facility as well as for the potential land application area surrounding the farm site. The geographic information system (GIS) database and model were used to produce maps and corresponding tables of facilities ranked by AWPI. Outputs were used as a screening tool to identify high-risk sites. Model evaluation based on 1253 farm sites in Rockingham County and 311 sites in Augusta County indicate a balance in site versus application area contribution to AWPI. For these two counties, the distribution of AWPI ratings is conducive to effective targeting. No relationship between animal type and AWPI was evident.