USING GIS REMOTE SENSING AND WATER QUALITY MODELING TO ESTIMATE ANIMAL WASTE POLLUTION POTENTIAL

Watersheds having a densepopulation of poultry production facilities frequently receive relatively high rates of poultry litter application. This often leads to surface and ground water pollution problems. The Stateof Alabama recently adopted an animal waste disposal regulation that requires farmers to adapt a waste management practice considering rate of application and watershed and land use characteristics. The objective of this study was to develop an animal waste pollution potential index (AWPPI) that can be used by farmers and regulators to rank areas based on susceptibility to nonpoint source (NPS) pollution from land application of poultry litter. This study was conducted in a watershed with an area of 56 mi2. The AWPPI was developed as a function of manure application rate, nutrient availability rate, and delivery ratio. The watershed data required for this method were derived from 7.5 minutes USGS digital elevation models. High resolution infrared aerial photos were used to derive information about number and location of poultry houses in the watershed. Two indices, N-based and P-based AWPPI, were evaluated in this study. No significant difference was found between the two indices. The AWPPI was found to be significantlycorrelated to poultry house density in a watershed and ratio of litter application area to watershed area. This method presents a simple approach to identify areas having higher susceptibility to NPS pollution and where best management practices may need to be implemented to reduce NPS pollution from animal waste application