Factors affecting sediment delivery rates in the red hills physiographic area

Twenty-five records of watershed sediment delivery rates and factors affecting sediment-delivery rates are analyzed. Relief and maximum length of watershed expressed as relief-length ratio (R/L) in a simple curvilinear correlation or as individual variables in a multiple curvilinear correlation are found to offer a much closer correlation with sedimentdelivery rates than size of sediment contributing area or several other factors tested. The basic trend of thought in this study is that rates of sediment yield of watersheds are immediately comparable only if their gross erosion rates per unit of area are the same. Otherwise, it is their delivery rates t h a t must be compared, and once causal factors of the sedimentdelivery rate have been evaluated for a soil and climatic region, it is possible to predict sediment yields closely from gross erosion data and the delivery rate characteristics of individual watersheds within that region.