How Much Water Is in the Apalachicola, Chattahoochee, and Flint Rivers, and How Much Is Used?

Questions of how much water is in the Apalachicola, Chattahoochee, and Flint (ACF) Rivers and how much is used do not have simple answers. The answers depend on the location in the river basin and on the year and season (as discussed on the first two pages of this fact sheet). Location is important because as one moves from upstream to downstream in a typical river, additions to streamflow from tributaries plus ground water and subtractions of streamflow from consumptive use are cumulative, with increasing total amounts in the downstream direction. Time is important because streamflow and consumptive use can vary by hundreds of percent from year to year and season to season at a given location; consumptive use typically is highest during droughts and summer months when streamflow typically is low.

Consumptive use is defined herein as the difference between the amount of water withdrawn from and the amount returned to a river. These amounts depend on several factors, particularly the type of water use, which varies from region to region (as discussed on the third page). Streamflow during low-flow periods comes primarily from ground water and can be affected by ground-water pumping (as discussed on the last page).

This fact sheet uses detailed consumptive water-use data for 1994-2001 that are not available for most watersheds in Georgia (Fanning, 2003; U.S. Army Corps of Engineers [USACE], 2004; James Hathorn, USACE, written commun., December 2006). The year 2000 is used herein for several examples because of the available consumptive-use data and because this was an extreme drought year. Additional research and information (as discussed on the last page) are needed to support reliable, fact-based water management and planning for the Georgia Comprehensive Statewide Water Management Plan (accessed March 2007 at http://www.gadnr.org/gswp/).