SS3.21 Deconstructing Rivers: The Ecological, Geomorphic, and Social Consequences of Dam Removal
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
Kinoshita Atsuhiko, Kyoto University, Kyoto, Japan, attsu@kais.kyoto-u.ac.jp
Mizuyama, T, , Kyoto University, Kyoto, Japan, mizuyama@kais.kyoto-u.ac.jp
Fujita, M, , Kyoto University, Kyoto, Japan, fujita@kais.kyoto-u.ac.jp
Sawada, T, , Kyoto University, Kyoto, Japan, sawad@ya2.so-net.ne.jp
 
AN EVALUATION METHOD OF THE IMPACTS ON FISH OF SEDIMENT FLUSHING FROM A SABO DAM
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The impacts on fish of sediment flushing from a sabo dam are evaluated from points of water quality and habitat. For the former, critical concentrations of dissolved oxygen and SS should be obtained for various physiological conditions. For the latter, the disappearance of habitat due to the sediment deposition and the restoration process should be investigated. The aims of this study are to make these two points clear and to know how to determine the conditions for low impacts on fish. Firstly, we have suggested a new model for evaluating the influence of turbidity. If the SS concentration increases too much, the gills of fish are blocked by sediment and the fish die of anoxia. On the basis of this idea, a method to calculate time variation of the mortality rate under a SS concentration has been presented. Secondly, we have developed a sediment movement model on a step-pool bed form. We have verified the application of these models to the impacts by sediment flushing experiments in a field and found that we can evaluate the impacts by these models.