The United States Weather Bureau had published Technical Paper No. 40 (TP-40) in 1961 which provides a rainfall atlas for the United States. These rainfall frequencies have been used by engineers throughout the United States including Jefferson Parish, Louisiana. Rainfall from Audubon and the New Orleans International Airport rain gauge stations were used with the Log Pearson Method to provide rainfall frequency for Jefferson Parish, Louisiana. The results from the frequency rainfall that were developed for this research along with the current Jefferson Parish design storm rainfall were applied to a typical urban development to evaluate the extent of flooding.