Systematic Pollutegraph Simulation for Real Scale River Basin

This study describes the model for predicting the run-off load of pollutants through rivers into eutrophic lakes and inner sea areas. The model is composed of three stages: discharged load prediction; flow-rate prediction; and run-off load prediction. The discharged load in the river basin is estimated by using a pollutant loading factor method. The flow-rate which is necessary for the formula to predict the run-off load, was obtained by a tank model method. The run-off load prediction process consists of two stages: flow-out stage and flow-down stage. The flow-out stage represents the process in which the discharged load, including that from non-point source, flows out through gutters or small streams into the main river. The flow-down stage represents the process in which the flow-out load flows down through the main river to an observing station. There have been many studies dealing with water quality and load of pollutants in rivers. However, only a few of these studies have analyzed the relationship of human activities in the river basins quantitatively. Using this model, a computer program for pollutegraph simulation was constructed and applied to the river Ibo in Hyougo prefecture, JAPAN. The results obtained showed in accordance with the data obtained from field investigation.