Abstract
Recently, the reduction of pollutant load from watershed becomes significant issue for the water quality management at a closed water area. Countermeasure for the nonpoint pollution load is urgently needed. In this study, to predict and estimate the amount of pollutant runoff from watershed under the rain condition, a numerical model was developed. The rainfall-runoff relation was calculated by the runoff function method, and the amount of pollutant-runoff was represented as the function of specific discharge. This model was applied to the prediction of the temporal variation of suspended solids (SS) at four rivers which are flowing into Isahaya flood regulation pond, Nagasaki. Computed results of the flood discharge and the runoff load of SS have good agreements with observed results, and the usefulness of this model was shown.
