Adjustment of Peak Discharge Rates for Urbanization.
HYDROLOGIC ENGINEERING CENTER DAVIS CA
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Various investigators have shown that changes from rural to urban conditions within a watershed, in general, significantly affect flood flows. Recorded annual peak discharge rates or peak discharge rates above a given base for a basin that has been undergoing a change in land-use conditions represent a nonstationary time series. The series must be adjusted to a specific land-use condition typically present conditions prior to performing a statistical frequency analysis. It was the aim of this note to present a procedure utilizing a single event rainfall-runoff model for transforming recorded peak discharges at a gaging station to a consistent set that reflects existing land-use conditions. Methods presented can be used as a guide to determine an existing-condition discharge frequency curve of annual peaks or peak discharge rates above a given base when utilizing a single event rainfall-runoff model. The multiplan-ratio option of HEC-1 permits the user to calculate systematically the hdyrologic response of several storm events for a given set of land-use conditions. The adjustment procedure described is also applicable when predicting runoff for estimated future conditions. Author
- Hydrology, Limnology and Potamology
- Civil Engineering