A methodology is developed to estimate the parameters of the Nash model (1957) and the converging overland flow model (Singh, 1974) of surface runoff, utilizing physically measurable watershed characteristics. These characteristics are investigated and used to derive equations to estimate the model parameters for small natural agricultural watersheds. Runoff hydrographs are predicted for several rainfall events on several of these watersheds. A comparison of the predictive performance of the two models indicates that both models performed equally well on these watersheds.

Project No. 3109-206