Apalachicola River Basin
The Apalachicola River flows unimpeded for 106 mi from Jim Woodruff
Lock and Dam to the Gulf of Mexico. The river drains about 2,600 sq mi
and its shallow estuary covers about 208 sq mi. Tidal influences do not
extend beyond 25 mi upstream from the river's mouth. The Apalachicola
River falls 40 ft as it flows through the Gulf Coast Lowlands. The
width of the river ranges from several hundred feet when confined to
its banks to nearly 4-1/2 mi during high flows. The discharge of the
Apalachicola River is 21st in magnitude among the rivers of the
conterminous United States, and is the largest in Florida, accounting
for 35 percent of freshwater flow on the western coast of Florida
(Livingston, 1992). During 1977-92, the discharge of the Apalachicola
River based on mean daily discharge at Sumatra, Fla., was 19,602 cfs.
Mean daily discharge at Sumatra ranged from 5,800 cfs in
1981 to 178,000 cfs in 1990.
Eighty percent of the Apalachicola River flow is contributed by the
Chattahoochee and Flint Rivers, 11 percent from the Chipola River, and
less than 10 percent from ground water and overland flow (Elder and
others, 1988). The Chipola River-Apalachicola River's largest
tributary-drains one-half of the Apalachicola River basin. The Chipola
River is classified as a spring-fed river with baseflow derived
principally from aquifers.
Because of rainfall-distribution patterns, the average annual runoff
from the Chattahoochee River exceeds that of the Flint River. The
Chattahoochee River makes a greater contribution to peak flows in the
Apalachicola River than the Flint River. However, during extreme dry
periods, the greater flow contribution in the Apalachicola River comes
from the Flint River, where baseflow is sustained by ground-water
discharges (Elder and others, 1988).
Leitman and others (1983) studied stage and discharge records from
1929-79 to determine if significant hydrologic changes occurred in
the Apalachicola River as a result of dam-flow regulation. Dams have
had little effect on the magnitude of high flows or seasonal
distribution of discharge over an annual cycle. Dam regulation did
reduce the amount of time that flow was at low extremes. Water stages
in the river within the first 30 mi downstream of Jim Woodruff Lock
and Dam have lowered due to scouring of the river bottom.
Text extracted from Couch and others, 1995
References
ACF NAWQA home page
The URL for this page is http://ga.water.usgs.gov
/nawqa/basin9.html
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Last Modified: Wednesday, 28-Jul-2004 10:01:44 EDT