FLUSING FLOW FOR IMPROVING HABITAT CONDIDONS OF STREAM BIOTA

Abstract

Biodiversity of streams is maintained by seasonal fluctuation of discharge and/or flow events. In regulated streams such as reaches below dams, however, flow events are controlled and discharge is not varied seasonally. The lower discharge and less flow events make degradation of the biodiversity of the stream. Ministry of Land, Infrastructure and transport, Japan, and electric power companies have examined suitable discharge to improve biodiversity of below the dam. We studied the most suitable size, season and frequency for the events on reaches below Taishakugawa Dam as a model case. We decide the event pattern in consideration of proportion of hydrograph, duration of rising and recession phases.