CALCULATION OF FLOOD DISCHARGES AND FLOOD HYDROGRAPHS IN KANSAS

Project developed specific design methodologies for (a) calculation of flood frequency relationships for both rural and urban conditions, and (b) calculation of flood hydrrographs for specified frequencies. The recommended procedures are based on the Frequency Equivalent Non-Linear Hydrograph (FENL-H) method developed at the University of Kansas. FENL-H utilizes a form of the modified rational formula Q = XZA where A = peak discharge in cfs, X = rainfall excess rate in inches/hr, Z is the ratio of peak discharge to the equilibrium discharge, and A is the drainage area in acres. The time of concentration and the time to equilibrium are presumed to be equal. Application of the FENL-H model to 110 Kansas basins for which peak discharge records were available during a common 17 year period clearly shows that the time of concentration decreases as the rate of rainfall excess increases. The data also indicates that the bulk of the unexplained variance in current flood frequency equations in Kansas can be attributed to a very nominal variance in the frequency distributions of the input rainfall. The design procedures presented in the report are believed applicable to watersheds ranging in size from 400 acres to 500 square miles.

• Supplemental Notes:
  • Prepared in cooperation with FHWA.
• Corporate Authors:

  Center for Research, Incorporated

  Kansas University, 2385 Irving Road
  Lawrence, KS  United States  66045
• Authors:
  • Smith, R L
  • Hauser, G E
• Publication Date: 1976-2

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 174 p.

Subject/Index Terms

• TRT Terms: Concentration (Chemistry); Drainage basins; Flood hydrographs; Floods; Mathematical models; Nonlinear equations; Peak discharge; Rainfall; Rational formula (Hydraulics); Rural areas; Urban areas; Watersheds
• Uncontrolled Terms: Concentration; Flood frequency; Models; Rainfall intensity
• Old TRIS Terms: Rational formula
• Subject Areas: Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00135920
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: FHWA-KS-RD-75-1 Final Rpt.
• Contract Numbers: HPR-KSDOT-75-1
• Files: NTIS, TRIS, USDOT
• Created Date: Sep 4 1976 12:00AM