HOW LAND USAGE, POINT SOURCES, POPULATION, AND BIG CITIES AFFECT THE WATER QUALITY OF SMALL AND LARGE WATERSHEDS IN GEORGIA

Weekly water quality monitoring of temperature, pH, DO, turbidity, specific conductivity, nutrients (total phosphorus, ammonia-N, and nitrite-nitrate-N) and fecal coliform bacteria in the Chattahoochee River 56 miles downstream of metro Atlanta in Carroll County was done for extended periods of time from 1999 to 2003. Monitoring included both weekly and 12-hour interval sampling during storm events. These results coupled with analysis of USGS long term monthly monitoring show how metro Atlanta increases nutrient, sediment and fecal coliform bacteria levels in the river. For example, the present nitrite-nitrate-N of 1.5 to 3.0 mg/L in the river at Carroll County is 5 times the values in the river upstream of metro Atlanta. The USGS sample site in Carroll County shows a ten-fold increase in nitrogen concentration has occurred from 1971 to 2003 in the Chattahoochee River. The city of Atlanta is facing costs of $3 billion for upgrades to sewage systems to correct pollution of the Chattahoochee River.

The Chattahoochee River is compared to the Little Tallapoosa River of Carroll County, Georgia. Our monitoring of the Little Tallapoosa River and its tributaries occurred for extended periods of time from 1990 to 2003. Even though several cities (Villa Rica and Carrollton) affect the Little Tallapoosa watershed (urban runoff, discharge of treated sewage, landfill, and spray field application of sewage) and it receives runoff from farmland (cattle pastures and fields fertilized with chicken litter), its water quality is better than the Chattahoochee River. For example, nitrite-nitrate-N for ten sample stations on the Little Tallapoosa River averages from 0.09 to 0.55 mg/L. Analyses of historic USGS data for other rivers with similar relationships with cities is presented for the Coosa River and Rome, Chattahoochee River and Columbus, Flint River and Albany, Ocmulgee River and Macon, and Savannah River and Augusta. Preliminary analysis of historic data indicate that even though population and urban sprawl increase a river’s water quality can be improved by concentrated human efforts such as bans on phosphate in detergents and improvements of sewage treatment methods. Thus, water quality of the Chattahoochee River downstream of Atlanta could improve with the proposed $3 billion upgrade to sewer lines and treatment plants.