Outline and present of Matsukawa Dam redevelopment project

Abstract

Matsukawa Dam is a multipurpose dam located in the Matsukawa River, in Iida City, southern part of Nagano Prefecture. It is constructed and managed by Nagano Prefecture. It has implemented flood control in several times since completion of 1975. The upstream of the Matsukawa Dam has been devastated by the Typhoon No.10 in September 1988 and etc. Because of this, there is a large amount of sediment exceeding the planned sediment volume at present. In the Matsukawa Dam, it is necessary to perform preliminary drawdown before flood control. Due to an issue of flood control function, Nagano Prefecture has been working on dam redevelopment projects to restore and improve the flood control function. The contents of this project are to introduce countermeasures to prevent reservoir sedimentation by construction of the sediment bypass facility and to solve complex operation rule with preliminary draw down, and to improve the flood control function by increasing storage volume through sediment excavation. At present, the sediment bypass facility has been completed and its test operation has been started from September 2016. In this paper, we will report the outline and current situation of Matsukawa Dam redevelopment project.