Methods are presented for estimating the peak dis- charges of rural, unregulated streams in Virginia. A Pearson Type III distribution was fitted to the logarithms of annual peak-discharge records from 363 stream-gaging stations in Virginia to estimate the peak discharge at these stations for recurrence intervals of 2 to 500 years. Peak-discharge characteristics for 284 stations were regressed on potential explanatory variables, including drainage area, main channel length, main channel slope, mean basin elevation, percentage of forest cover, mean annual precipitation, and maximum rainfall intensity, by using generalized least-squares multiple-regression analysis. Stations were grouped into eight peak-discharge regions based on the five physiographic provinces in the State, and equations are presented for each region. Alternative equations using drainage area only are presented for each region. Alternative equations using drainage area only are presented for each region. Methods and sample computations are provided to estimate peak discharges for recurrence intervals of 2 to 500 years at gaged and ungaged sites in Virginia, and to adjust the regression estimates for sites where nearby gaged-site data are available.
Additional publication details
USGS Numbered Series
Methods for estimating the magnitude and frequency of peak discharges of rural, unregulated streams in Virginia
Water-Resources Investigations Report
U.S. Geological Survey ;
U.S.G.S. Earth Science Information Center, Open-File Reports Section [distributor],