South Atlantic Water Science Center

Due to a lapse in appropriations, sampling for Bacterialert has been temporarily discontinued. Additionally, USGS will not be able to respond to inquiries until appropriations are enacted. For more information, please see

Chattahoochee River BacteriAlert: Introduction

Map of the study area.

This Web site provides the users of the Chattahoochee River and citizens of Atlanta with current predictions of E. coli bacteria concentrations for sites on the Chattahoochee River. Predicting bacteria concentrations in "real time" requires using other indicators, in this case turbidity, that have a correlation to bacteria. Estimating bacteria concentrations from turbidity is a new and inexact science, and the statistical model that ties the two together is not just a simple straight-line correlation.

Because of historically high levels of indicator bacteria in the Chattahoochee River, the concept of a bacteria alert network was proposed as a means to inform people when bacteria levels in the river exceed U.S. Environmental Protection Agency (USEPA) criteria. Thus, a program of bacteria monitoring called BacteriALERT was initiated on the Chattahoochee River within the Chattahoochee River National Recreation Area (CRNRA, National Park Service) in Fall 2000. The CRNRA contains about three-fourths of all public green space in a 10-county area of Metropolitan Atlanta, Georgia. In 1999, the recreation area attracted about 2.9 million visitors with nearly 30 percent of those participating in water-based recreation. Within the area of the bacteria alert network, drinking water and recreation are the designated uses for the Chattahoochee River.

BacteriALERT is a partnership between Federal, State and local agencies and non-government organizations. This partnership includes the National Park Service, the U.S. Geological Survey, Cobb County Water System and the City of Roswell, along with non-governmental organizations such as the Chattahoochee RiverKeeper and the Chattahoochee Parks Conservancy.

The main objective of this network is to collect and analyze water samples for total coliform and Escherichia coli (E. coli) bacteria. Results are posted on a publicly-accessible web site within 24 hours of data collection. A second objective is the statistical analysis and interpretation of these data under a wide range of seasonal, weather, and river conditions.