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Estimating flood hydrographs for urban basins in North Carolina

Water-Resources Investigations Report 96-4085

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Abstract

A dimensionless hydrograph for North Carolina was developed from data collected in 29 urban and urbanizing basins in the State. The dimen- sionless hydrograph can be used with an estimate of peak flow and basin lagtime to synthesize a design flood hydrograph for urban basins in North Carolina. Peak flows can be estimated from a number of avail- able techniques; a procedure for estimating basin lagtime from main channel length, stream slope, and percentage of impervious area was developed from data collected at 50 sites and is presented in this report. The North Carolina dimensionless hydrograph provides satis- factory predictions of flood hydrographs in all regions of the State except for basins in or near Asheville where the method overestimated 11 of 12 measured hydrographs. A previously developed dimensionless hydrograph for urban basins in the Piedmont and upper Coastal Plain of South Carolina provides better flood-hydrograph predictions for the Asheville basins and has a standard error of 21 percent as compared to 41 percent for the North Carolina dimensionless hydrograph.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Estimating flood hydrographs for urban basins in North Carolina
Series title:
Water-Resources Investigations Report
Series number:
96-4085
Edition:
-
Year Published:
1996
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Branch of Information Services [distributor],
Description:
iii, 19 p. :ill., maps ;28 cm.