Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


The DR3M (Distributed Routing Rainfall-Runoff Model) was used to simulate annual flood series for various stages of urban development in the Ward Creek drainage basin above the Government Street bridge in Baton Rouge, Louisiana. Synthesis of flood hydrographs by DR3M illustrates a feasible method for estimating flood characteristics in watersheds for various degrees of existing or projected development. Changes in percent effective impervious area, and overland and drainage channel roughness coefficients were varied for the Ward Creek watershed to simulate various stages of urban development. Presently (1986) Ward Creek has 27 percent effective impervious area. Annual flood series were synthesized for 1, 20, 40, 60, 80, and 99 percent effective impervious area. The Log Pearson Type III distribution was applied to each flood series to provide an estimate of flood magnitude and frequency for each stage of urban development. An increase from 20 to 80 percent effective impervious area resulted in an 164 percent greater 2-year peak discharge and a 48 percent greater 50-year peak discharge. The development of residential, commercial, and industrial areas add large amounts of impervious area to previously undeveloped watersheds. This increases storm runoff and peak flow. Improvement of existing waterways and the addition of gutters, curbs, and storm sewers reduces runoff response time and further increases peak flows. Suggestions for reducing flood hazards due to future development are made.