EVALUATION METHOD OF DREDGE EFFICIENCY IN FISH NESTS USING HYDRODYNAMIC AND MORPHODYNAMIC MODEL

Abstract

 Maintenance of eco-friendly physical structures according to the situation after their construction is indispensable in order for the structures to continue to exert the biological conservation function intended at the time of design. In this study, "mud removal" that dredges excessive sediment in fish nests in an agricultural drainage canal was focused, and a method for evaluating dredge efficiency was presented. The two-dimensional hydrodynamic and morphodynamic model was applied to an actual agricultural drainage canal section with fish nests and a fish pool, and the sedimentation tendency in the target section was reproduced. Comparing the reduction rates of dredge effect by assuming multiple patterns of mud removal in specific fish nests on the left bank leads to evaluating the sustainability of the dredge effect associated with the amount of dredged soil. This method could provide useful information for adaptive management of fish nests, such as selection of mud removal area where the dredge effect is likely to be sustained and determination of the amount of dredged soil.