<原著論文>

加古川流域での水資源開発に伴う河川の流況と海域へ流入する河川流量の変化

大嶌 巌^*1

^*1水資源を考える会　〒166-0002 東京都杉並区高円寺北1-27-8-301

Influence on the River Flow Regime and the River Flow to the Sea by Development of Water Resources at the Kako River Basin.

Iwao Ohshima^*1

^*1Water resource study group，Kouenji-kita 1-27-8-301, Suginami-ku, Tokyo 166-0002, Japan

Abstract

The Kako River is the longest first class river in Hyogo Prefecture. The Kako River weir started operating in 1989，and the weir and the dams of upper and middle reaches of the weir started operating integrally in 1992. This study tried to quantify the change of river flow regime and the decrease of river flow to the sea by development of water resources at the Kako River basin. The study found the following two results after integrally operating start of the Kako River weir and the dams: 1) the 95-day and 185-day discharge at Kunikane decreased significantly; and 2) the river flow from the Kako River mouth to the sea decreased by 20.5% per year under the mean precipitation. It was thought that it is important to evaluate the influence of the estuary environment by the results of seawater quality and estuary simulation model in future.

Key Words : Development of water resources, Kako river basin, Kako river weir, decrease of river flow

(Received December 23, 2018. Accepted May 6, 2019)