FREQUENCY ANALYSIS OF ILLINOIS FLOODS USING OBSERVED AND SYNTHETIC STREAMFLOW RECORDS
Equations, applicable statewide, for estimating flood magnitudes having recurrence intervals ranging from 2 to 500 years for unregulated rural streams, with drainage areas ranging from 0.02 to 10,000 square miles (0.05 to 25,900 square kilometers), were derived by multiple regression analyses. A rainfall-runoff model was used in the synthesis of long-term annual peak data for each of 54 small watersheds (drainage areas less than 10.2 sq mi, 26.4 sq km). Synthetic frequency curves generated from five long-term precipitation stations were combined into one synthetic curve and then this synthetic curve was combined with the observed station frequency curve to define the station frequency curve. Synthetic data from the 54 small streams, observed data at 33 small streams, and observed data at 154 large streams were used in the analyses. The most significant independent variables in the regression analysis for estimating flood peaks on Illinois streams were drainage area, slope, rainfall intensity, and an areal factor.
- Prepared in cooperation with Illinois State Div. of Highways, Springfield.
U.S. Geological SurveyF Street Between 18th and 19th Street, NW
Washington, DC 20244
Illinois Department of TransportationDivision of Highways, 2300 South Dirksen Parkway
Springfield, IL USA 62764
- Curtis, G W
- Publication Date: 1977-7
- Pagination: 40 p.
- TRT Terms: Bridges; Design; Drainage; Evaporation; Flood protection; Floods; Flow; Forecasting; Highways; Mathematical models; Rain; Rainfall; Regression analysis; Runoff; Rural areas; Slopes; Stream gages; Streamflow; Streams; Watersheds
- Uncontrolled Terms: Design criteria; Rainfall intensity
- Geographic Terms: Illinois
- Subject Areas: Bridges and other structures; Data and Information Technology; Design; Hydraulics and Hydrology; Railroads;
- Accession Number: 00175897
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: USGS/WRI-77-104 Final Rpt.
- Files: TRIS
- Created Date: Jun 28 1978 12:00AM