Hydrometeorology of Heavy Rainstorms in Chicago and Northeastern Illinois, Phase I—Historical Studies

This report presents the results of an investigation of the distribution of heavy rainstorms in the Chicago urban area and the surrounding six counties, based on available historical rain data (primarily 1949-1974). The six counties are Cook, Du Page, Kane, Will, Lake, and McHenry. Presented are frequency distributions of point rainfall for rain periods from 5 minutes to 72 hours and recurrence intervals of 6 months to 50 years. Also presented are point-area relationships, frequency distribution of storm centers, diurnal and seasonal distribution of heavy storms, orientation of heavy storms, storm shapes, synoptic weather conditions associated with severe rainstorms, time between heavy rain occurrences, and time distribution characteristics of rainfall during heavy storms. Results are pertinent to design of hydraulic structures such as storm sewers. This historical study is the first phase of a comprehensive hydrometeorological research program for northeastern Illinois that will include, as the next phase, an extensive field measurement project in the area.publishedpeer reviewedOpe