Fishway Design Methodology Based on New Concept for River Environment

Abstract

Previously, fishways were designed to assist migration of only commercial fish. However, new emerging concept of river environment management requires fishways to provide “biopath” for many species of fish. In this paper, the new methodology for fishway design is discussed. IFIM (instream flow incremental methodology), which was derived for habitat evaluation, is here developed to apply to fishway evaluation. Not only the hydraulic condition of flow in fishway but also the influence of time series of discharge are taken into account to evaluate the fishway design. The procedure of the methodology is explained for an example of fishway of triangular section with large roughness.