Document Type


Publication Date

January 1970


This study developed a general method for estimating runoff rates and associated confidence limits of a given recurrence interval for ungaged small urban watersheds. The utility of the method developed was demonstrated through its application to a southeast region of Texas. Some 200 historical rainfall-runoff events from 40 watersheds in the Houston, Austin, Dallas, and Fort Worth urban areas were analyzed. Watershed data such as drainage area, percent of urbanized area channel length, average channel slope, land slope, and soil type are documented. Total rainfall amounts, intensities, durations, and mass-time distributions were determined for each storm and used to develop a rainfall generating model. Peak runoff, total runoff volume, and runoff duration were also determined. Statistical analyses were performed to develop regression models to relate peak runoff and total runoff volume with rainfall and watershed characteristics as independent variables. An urban watershed runoff model, abased on the Utah Simulation Model, was used to identify the model parameters for each watershed by reproducing the historical storms. Relationships between model parameters and measured watershed runoff model, peak runoff rates and total runoff volumes for different conditions were generated for chart construction.