|Wilkinson, Stanley - USDA-ARS RETIRED|
Submitted to: Forest Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 17, 1999
Publication Date: N/A
Interpretive Summary: Detailed knowledge of the location of various land uses such as dairy, poultry, and cities can be used to identify creeks, rivers, and lakes that are most likely to be contaminated by pollutants. The Upper Oconee Watershed of Georgia contains agricultural land devoted to poultry, dairy, and beef production. Agriculture is concentrated with poultry located mostly in the north and dairy in the southwest near Lake Oconee. We did this research to relate data representing water quality at selected sites throughout the watershed to the predominant land use in that portion of the watershed. Water quality was lower near the poultry but increased within the watershed prior to reaching the Athens municipal intake. Athens had a large negative impact on water quality. The dairies located west of the lake impacted two relatively minor creeks flowing to the lake but were very visible to homeowners near the lake. We found that tests for two specific bacteria provided better tests for fecal contamination and allowed differentiation between natural areas and areas impacted by grazing animals. Analysis of the Upper Oconee Watershed identified land uses that had negative impacts on water quality and can help prioritize areas for natural resource management.
Technical Abstract: Geospatial data can be used to identify water resources that are least buffered from contamination. The Upper Oconee Watershed of Georgia contains land areas devoted to poultry, dairy, and beef production. The objective of this research was to relate data sets representing surface water quality at selected sites throughout the watershed to the predominant land use in that portion of the watershed. Phosphorus, nitrogen, and fecal coliform bacteria were higher near the poultry production area but were reduced within the watershed prior to reaching the intake for the municipal water supply. Athens had a large negative impact on surface water quality. The residents of Lake Oconee have noted the dairies located west of the lake. The proximity of the dairies to the lake makes losses of phosphorus, nitrogen, and fecal bacteria apparent. To test alternative microbial assays, surface water from a grazed watershed was compared to water from a wooded watershed. Assays for enterococci and E. coli may provide a better test for fecal contamination and allow differentiation between natural areas and areas impacted by grazing animals. Analysis of the Upper Oconee Watershed identified agricultural impacts and areas that should be priorities for natural resource management.