Determination of Flood Hydrographs for Streams in South Carolina. Volume 1. Simulation of Flood Hydrographs for Rural Watersheds in South Carolina

摘要

A typical (average) flood hydrograph corresponding to a peak discharge of specific recurrence interval can be simulated for ungaged rural basins having drainage areas less than 500 square miles in South Carolina. Three dimensionless hydrographs were developed on the basis of data collected during 188 storm events at 49 stations representing a wide range of drainage area sizes and basin conditions. The design peak discharge and a volume-adjusted average basin lagtime are required to apply the technique. The standard errors of estimate for simulated hydrograph widths at 50 and 75 percent, respectively, of observed stormflow were + or - 14.1 and + or - 18.3 percent for basins in the Blue Ridge physiographic province. Multiple-regression analyses were used to develop equations for estimating average basin lagtime. The hydraulic design of highway drainage structures involves an evaluation of the flood hazard to the highway and of the effect of the proposed structures on the hazard to lives, property, and stream stability.