The rainfall intensity–duration–frequency (IDF) relationship is one of the most widely used and most important hydrologic tools utilized by engineers in water resources engineering field, either in planning, designing and operating water resources, or flood control projects. The IDF curves are commonly used to assess rainfall events, to derive design storms and assist in designing drainage structures, storm sewers, culverts and other hydraulic structures in urban areas. The purpose of this research is to derive rainfall IDF curves of Helen, Georgia. Helen is a city in White County, Georgia, United States. It is a mountain town in northeast Georgia, located along the Chattahoochee River. Gumbel and the Log Pearson Type III distribution frequency analysis techniques will be used to develop the IDF curves from rainfall data of the region. The frequency analysis of available rainfall data and the parameters of the IDF equations and coefficient of correlation will be calculated by statistical methods to attain rainfall intensities for various short durations and return periods. Keyword: IDF, Gumbel, and Log Pearson Type III
