Application and verification of several rainfall-runoff models in Hawaii

Abstract

The need for reliable predictive models for water resources decision making provided the impetus to apply several rainfall-runoff models, developed for the continental United States, to an urban watershed in Hawaii. In this study, the Illinois Urban Drainage Area Simulator (ILLUDAS), the Penn State Urban Runoff Model (PSURM), and the Quasi-Linear Spatially Distributed Cell Model (CELMOD) were applied to the St. Louis Heights Watershed. Parameter values were determined for each model on the basis of peak discharge, time to peak and runoff volume accuracy. These characteristics were then used to evaluate the models. Each model performed well in simulating the observed hydrographs, but the ILLUDAS was the most successful in simulating peak discharge. Studies into the relationship between the infiltration response and the Soil Conservation Service soil grouping, and application of Izzard's equation to a wider range of conditions would facilitate the application of these models.