Methods are provided for estimating flood magnitudes at recurrence intervals of 2, 5, 10, 25, 50, and 100 years, for unregulated rural streams in South Carolina with drainage areas greater than 1.0 square mile. Multiple regression analyses were used to define the relation between flood discharge and basin and climatic variables. The analyses indicated that flood discharge is related to the drainage area and physiographic location of the basin. Accordingly, equations were developed for the Lower Coastal Plain, Inner Coastal Plain, Piedmont, and Blue Ridge provinces. The standard errors of estimate range from 31 to 56 percent. Station data used in the analyses are listed in the report.
Individual relations of flood discharge and frequency to drainage area are given for some of the regulated major streams, including the Pee Dee, Catawba, Wateree, Broad, Saluda, Congaree, Santee, and Savannah Rivers. Storm tide-recurrence interval relations along the South Carolina coast indicate that the 500-year tide height can exceed 19 feet, National Geodetic Vertical Datum of 1929, at some locations.
A compilation of flood records for gaging stations is included as supplemental data.
