CHANGES OF SS LOAD IN SIROMARU REGULATING RESERVOIRDAM AND INFLUENCE ON THE BENTHIC ORGANISMS ABOUT TURBIDITY

It is an important subject tomanage sedimentation of dams appropriately so that the continuity of rivers maybe maintained and the influence of the ecosystem on the downstream site may be made to reduce in lateyears. And it is necessary to examine measures of turbid water. In this study, changes of a pollutant load which sediment affects are cleared quantitatively on Siromaru Dam. Relation between turbidity and the diversity of benthic animals are clarified using a stochastic method. The correlating equation of between turbidityand SS was obtained reliably bycalculation of a pollutant load. And an annual discharge-duration curve on the turbidity has been created. A significant relation is accepted, that is between the non-exceeding probability of 355-day turbidity and the Simpson index using stochastic methods of turbidity and benthic animals. This relation is suiting a convex quadratic curve and having the maximum of diversity. Therefore, it became clear that the suitable non-exceeding probability, namely, moderate disturbance frequency exists.