Estimating nonpoint source pollution loading from animal wastes

Water is valuable because of its many uses. As the quality of water degrades, so does its value and usefulness. For this study, the water quality impacts from livestock wastes and grazing activities are estimated. A hydrologic model. Soil and Water Assessment Tool, is used to estimate the pollution loading from a watershed. The Big Shoal Creek watershed located in Alabama is selected as the study area. The analysis consists of simulating the sediment and nutrient impacts from four pastureland conditions; pastureland only, the application of animal wastes (manure), and grazing activities for 180 days and 365 days. The study clearly demonstrated the large increases in pollution loading due to animal wastes. The addition of grazing activities increased the pollutant loads to over 100% as compared to manure additions only. However, the pollutant loads were significantly reduced during controlled grazing operations (180 days) as compared to unmanaged grazing operations (365 days).