Abstract
It is an important subject to evaluate adequately the storm runoff loading for the preservation of water quality environment in the stagnant water bodies. In this study, we analyzed the effects on the estimation of storm runoff loading using hourly observed data (rainfall, river flow and water quality) at two head works located in the middle of the Yahagi River basin, and applied simple regression models to estimate loading. Firstly, we observed closely relationships among rainfall, river flow, water quality concentration and loading. Secondly, by evaluating the difference between estimated and observed loading rate during the rainy period, we proposed conditions for upgrading the accuracy of loading estimation. Thirdly, we analyzed factors that affect storm runoff loading from the hydrologic aspects, and found relationships between the cumulative loading residual and the factors such as antecedent dry weather period. Finally, some conditions on the estimation for storm runoff loading are summarized which include the improvement in the application of the regression models to estimate loading.
