The Agi River connects with the Kiso River just below Ōi Dam, running through a basin with a fairly large 2,000 mm of annual rainfall, and has long been used by Gifu Prefecture's Tōnō region (which includes the cities of Ena, Gifu, Ena and Nakutsugawa) for tap water and industrial-use water.

Attempts to meet water demand for Aichi Prefecture came up short, with the Makio Dam on the Ōtaki River alone proving insufficient.

Water was also in short supply in Gifu Prefecture's Tōnō region, centering on Tajimi City, sometimes escalating to drought.

With this, the construction of the multi-purpose Agigawa Dam continued, with the goal of leveraging both flood prevention and better water usage.

The dam is located near the main part of Ena City, and residents also opposed it on grounds that it would've disrupted the area's excellent transportation; negotiations stalled.

On the right bank of the dam there is a small museum, restaurant, park, and other facilities, providing a recreational spot for the people of Ena.