Abstract

Concentrated animal feeding operations (CAFOs) contain large quantities of dairy cows and therefore have the potential to contribute significant amounts of harmful waste products to the environment. Although previous studies have used geospatial tools to assess potential contaminant runoff, the results from these studies are dependent on the unique geographical characteristics of specific regions. This study incorporated geographical characteristics unique to California to: 1) characterize the distribution of dairy CAFOs in California; and 2) determine and compare the potential for dairy CAFOs in high vs. low runoff potential regions in subject counties to contaminate surface water. The CAFOs were grouped by their location in either high or low runoff potential regions characterized by Curve Number (CN) grids. The potential for the CAFOs in either group to contaminate surface water was determined by calculating the proportion of CAFOs with runoff that intersected with surface water. Among the CAFOs in high runoff potential regions, 180 out of 193 facilities had the potential to contaminate surface water. This proportion was found to be significantly different from the proportion of CAFOs in low runoff potential regions (p=0.023), indicating validity of the CN grids used to approximate runoff potential.

Key words: Concentrated animal feeding operation (CAFO), dairy, water pollution, geographic information system (GIS), curve number (CN) grids