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Georgia flood-frequency regions and regional
regression analysis
Region 1 includes all of the Valley and Ridge, Appalachian Plateau, and the Blue Ridge physiographic provinces, and part of the adjacent Piedmont physiographic province. Region 1 also includes the headwaters of the Savannah, Tennessee, Tallapoosa, and Mobile River basins; all of the Etowah River basin; and the Chattahoochee River basin upstream in the vicinity of Franklin, Ga.

Region 2 includes most of the Piedmont Province, part of the Coastal Plain Province (including the upstream portion of the Flint River downstream to near Reynolds, Ga.), and the Ocmulgee River basin upstream from Macon, Ga. Region 2 also includes all of the Broad River basin, the Oconee River basin upstream of Milledgeville, Ga., and the part of the Ogeechee River basin upstream of Shoals, Ga.

Regions 3 and 4 are in the Coastal Plain physiographic province. The northern boundary of Region 3 approximates the fall-line boundary between the Piedmont and Coastal Plain Provinces. Region 3 includes the basins of the Ocmulgee (downstream of Macon), Flint (downstream of Reynolds), Alapaha, Suwanee, Ogeechee (downstream of Shoals), Canoochee, Oconee (downstream of Milledgeville), Altamaha, and Satilla Rivers. Region 4 includes all of the Ocklockonee River basin and most of the Withlacoochee River basin. Flood-magnitude and -frequency relations were not determined for the basins draining the Okefenokee Swamp.

  Maps showing the flood-freqeuncy regions and physiographics provinces of Georgia.

More detailed maps can be found in figures 1-5 in USGS Water-Resources Investigations Report 93-4016.

Region flood-frequency relations for rural streams in Georgia
Flood discharge,Qn,
for n-year
recurrence interval		 Flood-frequency relations for indicated regions in the form Qn = aAb, where A is the drainage area, in square miles, and a and b are as presented below
 Region 1Region 2Region 3Region 4
Q2207A.654182A.62276A.620142A.591
Q5357A.632311A.616133A.620288A.589
Q10482A.619411A.613176A.621410A.591
Q25666A.605552A.610237A.623591A.595
Q50827A.595669A.607287A.625748A.599
Q1001,010A.584794A.605340A.627926A.602
Q2001,220A.575931A.603396A.6291,120A.606
Q5001,530A.5631,130A.601474A.6321,420A.611
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This URL: http://nts4dgaatl.er.usgs.gov:80/floodfrequency/analysisinfo.cfm
Last updated: 11/28/2001 10:12:17 AM

Note: Information and data on this Web site come from "Techniques for Estimating Magnitude and Frequency of Floods in Rural Basins of Georgia," USGS Water-Resources Investigations Report 93-4016, by Stamey, T.C., and Hess, G.W., 1993

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