Response of Fish Habitat Quality to Weir Distribution Change in Mountainous River Based on the Two-Dimensional Habitat Suitability Model

Weirs are often constructed on mountainous rivers because of their low construction costs and ability to provide irrigation facilitate landscaping, yet there is little research how fish habitat quality in responds weir distribution. This study categorized the distribution characteristics weirs typical reaches according sinuosity calculated corresponding suitability index (HSI) weighted usable area (WUA) under various discharge conditions using a coupled MIKE21 model. Then, relationship between habitats different was analyzed. The results show that can affect rivers, but this effect closely related layout mainly key hydraulic factors determine for sinuous vary conditions. found high-sinuosity with high conditions, water depth factor determining habitats, so improve by improving downstream depth. However, other velocity quality, which case cannot even degrade it. Therefore, methods needed enhance quality. reference protection river channels determination suitable locations construction.