by Michael F. Peck and Jerry W. Garrett
ABSTRACT
Surface- and ground-water quality data were collected and evaluated from streams and wells in the White Creek and Mossy Creek watersheds in White County, Georgia, during three sampling periods in 1992 and 1993, to identify stream reaches and wells affected by nonpoint-source contaminants. Livestock operations in these watersheds account for approximately 9.8 million tons of manure per year, which is spread over about 5,000 acres of pasture and cropland in the watersheds. White Creek and Mossy Creek are tributaries of the Chattahoochee River which flows into Lake Sidney Lanier. Lake Sidney Lanier and the Chattahoochee River downstream from the lake are the primary sources of drinking water for the Atlanta Metropolitan area and numerous smaller communities downstream of Atlanta.
Water samples were collected from 31 stream sites during baseflow and stormwater-runoff conditions and from 8 shallow wells completed in the regolith and 16 deeper wells completed in the crystalline bedrock. All water samples were analyzed for the nutrients ammonia, nitrite plus nitrate, and orthophosphate. None of the surface-water samples from either sampling period had concentrations of these constituents that exceed the Georgia Department of Natural Resources, Environmental Protection Division (EPD), drinking-water standards. Generally, in both watersheds, the streamwater temperature was cool, specific conductance low, dissolved oxygen was high, and pH was near neutral. Ground-water samples collected from 8 shallow regolith wells and the 16 deep bedrock wells had nutrient concentrations below EPD drinking-water standards, except for two of the deep bedrock wells with nitrite plus nitrate concentrations slightly above the 10 mg/L drinking-water standard of EPD.