South Atlantic Water Science Center - Georgia
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The Apalachicola-Chattahoochee-Flint (ACF) River National Water Quality Assessment (NAWQA) Program study
Basin Description: Chattahoochee Basin Surface-Water Hydrology
The Chattahoochee River-whose name is derived from Creek Indian words meaning painted rock-drains an area of 8,770 sq mi and is the most heavily used water resource in Georgia. The Chattahoochee River arises as a cold-water mountain stream in the Blue Ridge Province at altitudes above 3,000 ft and flows 430 mi to its confluence with the Flint River. The discharge of the Chattahoochee River based on median daily flows near Columbia, Ala., during water years 1977-92 was 8,250 cubic feet per second (cfs). Median daily discharge ranged from a low of 498 cfs in 1989 to a high of 191,000 cfs in 1990.
Thirteen of 16 dams on mainstem locations in the ACF River basin are on the Chattahoochee River. Dam construction in the basin began in the early 1800's on the Chattahoochee River above the Fall Line at Columbus, Ga., to take advantage of natural gradients for power production. Annual flow has not been appreciably altered by the system of dams, although storage is used to augment flows during periods of low flow; and daily fluctuations below some reservoirs can be dramatic. Pronounced decreases in the frequency of high and low flows have occurred since the start of operation of Buford Dam that forms Lake Sidney Lanier. Lake Sidney Lanier, West Point Lake, and Lake Walter F. George provide most water storage available to regulate flows in the basin. Lake Sidney Lanier alone provides 65 percent of conservation storage, although it drains only 5 percent of the ACF River basin. In addition, West Point Lake and Lake Walter F. George provide 18 and 14 percent, respectively, of the basin's conservation storage (Leitman and others, 1991).
Over most of its length, the flow of the Chattahoochee River is controlled by hydroelectric plants releasing water for production of hydropower. These hydroelectric plants use hydropeaking operations to augment power supply during peak periods of electric demand. At Cornelia, Ga., the Chattahoochee River is free flowing; however, throughout the remainder of its length, the river's hydrograph shows the influence of hydropeaking operation. Hydropeaking operations can result in daily stage fluctuations of 4 ft or more.
In contrast to the mainstem Chattahoochee River, many tributaries remain free flowing. Flows of tributaries in forested basins are represented by Snake Creek that drains 35.5 sq mi above streamflow-gaging station 02337500. Flows typical of urban basins are represented by Peachtree Creek. Above streamflow-gaging station 02336300, Peachtree Creek drains a 86.8 sq mi urban basin in Metropolitan Atlanta. Similar to most Piedmont streams, both streams have higher sustained flows during winter months, and show responses to storm events throughout the year. However, sharper peaks in the hydrograph of Peachtree Creek reflect the greater influence of impervious land cover in this urban basin.
Text extracted from Couch and others 1995.