The Itō-Ōkawa River is a primary source of drinking water for the city of Itō, on the eastern coast of the Izu Peninsula.

From the 1960s, the area around Itō began to develop as a bedroom community for Atami, as well as a popular vacation destination due to its beaches, hot spring resorts and ease of access to Tokyo.

Due to the geography of the site, a rock-fill dam design with a central spillway and a height of 63 meters was selected.

However, due to difficulties arising from transporting the necessary stones from distant locations, work was not completed until 1989.

The reservoir impounded was named Lake Matsukawa (松川湖, Matsukawa-ko) in 1987, and is a popular recreational area for sports fishermen and bird-watching.