The Effect of End-sill Geometry on Functionality of In-ground Stilling Basin

Abstract

流水型ダム下流に設置される減勢工の設計には，土砂や魚類の安全な通過のための課題が残されており，改善が求められている。本研究では，河川環境に対する適合性を高めるために，ダム直下を潜り跳水式とした新しい減勢工形式について，その考え方と水理設計上の課題について検討を行った。ここでは，減勢工下流に設置されるエンドシル高さと形状に着目して水理実験を行った。その結果，減勢機能を満足しつつ，土砂や魚類の通過機能も満たすことが可能な減勢工形状を結果を得ることができた。

In practice, design of stilling basin downstream of Flood Mitigation Dams (FMDs) is still facing several problems such as blockage of sediment passage and fish migration; and thus, it is necessary to improve its design. In this paper a new concept of stilling basin for FMDs is introduced; called In-ground Stilling Basin (ISB). Present study mainly focuses on experimental investigation on end-sill geometry at the end downstream of ISB. As results, several unique outcomes of experimental investigations have been obtained to improve the performances of FMDs as well as facilitate the fish and sediment passage.