Procedure for Developing Design Hyetographs for Small Watersheds

ABSTRACT A study of the time-distribution of 43 years of rainfall records revealed an advanced pattern as the most common at Coshocton, Ohio. Intermediate pattern storms, similar to the SCS design mass curves, were second in number. An equation was derived for estimating number of storms required to develop representative rainfall patterns for which intensities fall within a specified confidence interval. A statistical procedure (the bootstrap method) was followed to develop six rainfall temporal patterns of 50% probability. The procedure could be applied at other locations.