洪水バイパス運用に伴う下流河川環境についての考察

抄録

Recently sediment bypass systems have been planned and constructed as effective countermeasures against sedimentation in reservoirs. And, when a large amount of sediment is discharged to downstream rivers, accompanying environmental impact assessment should be performed properly. In this study, we conduct some practical consequences on basis of observations and analyses in Miwa Dam, where a redevelopment project is just being carried out. We calculated the suspended solids (SS) concentration increases at downstream river points and changes such as continuation time of the peak SS concentration and the high SS concentration during bypass systems working. Next, we examined the practical use time of the bypass system in consideration of the influence on the downstream rivers. We introduced about the monitoring plan such as the water survey and creature investigation, which it is thinking about at present.