81 Environmental Geoscience (Posters) I

THE PAST, PRESENT, AND FUTURE OF THE CHATTAHOOCHEE RIVER: HISTORICAL TRENDS AND PRESENT WATER QUALITY ANALYSIS AS PREDICTORS OF THE FUTURE

Paper number: 81-12
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

The headwaters of the Chattahoochee River originate in the Blue Ridge Mountains of northwest Georgia at Chattahoochee Gap. This area, upstream of Atlanta, consists of forest and agricultural lands and contains a number of poultry farms. The city of Atlanta withdraws more than 300 million gallons of water a day and discharges more then 200 million gallons of wastewater. In the heavily populated metro area of Atlanta, industrial as well as individual wastes pose water quality hazards. The seventy-mile stretch downstream of Atlanta is among the most polluted stretches of river in the nation. Possible sources of fecal coliform include run-off from pastures (primarily cow manure), septic tanks, and discharge of sewage. Sources of nutrients include sewage, fertilizer, and chicken manure. Construction, deep weathering, agriculture, low bank slopes, and large rainfall events affect the level of total suspended solids. The effects of degradation on the banks of the Chattahoochee River can be observed upstream of Helen, Georgia, near the headwaters. The result is increased erosion which causes the river to become muddy and contributes to more than 200,000 tons of sediment that fill up Lake Lanier, which is directly downstream of Helen.

Our research beginning in 2002 and extending through the summer of 2003 consists of continuous weekly monitoring and 12-hour interval sampling taken after rain events from the Chattahoochee River in the Whitesburg area. Whitesburg is about 50 miles downstream of metro Atlanta. Our water quality studies of the Chattahoochee River include fecal coliform bacteria, nutrients (ammonia-N, nitrite-nitrate-N, and total phosphorus), pH, dissolved oxygen, turbidity, specific conductivity, and total suspended solids. Our current and past research, long-term monitoring from the USGS, history of and predicted population growth, and the development and changes of land usage provide a model for the prediction of the Chattahoochee River water quality parameters in the future. Both total phosphorus and ammonia-N increased from 1970 to 1990, and have declined to today’s relatively low levels. Currently, the median level of nitrite-nitrate nitrogen in the river at Whitesburg is 1.81 mg/L. If past trends continue nitrite-nitrate nitrogen values will rise to 2.3 mg/L by 2010 and 3.1 mg/L by 2025.