Straddling the border between the village of Kitashiobara and the town of Inawashiro, it serves as a reservoir, supplying drinking water to local residents.

In 1888, Mount Bandai, located to the south, erupted, causing part of the mountainside to cave in due to a phreatic explosion.

[citation needed] The resulting rockslide, which turned into a mudslide, created a natural dam that blocked the flow of the Nagase and Onogawa rivers into the Inner Bandai area, causing it to flood.

To ensure an effective energy supply, an earth dam was built to increase the lake's storage capacity.

When completed, Akimoto Power Plant had a permitted output of 107,500 kW, which was the highest on the Agano River water system at that time.

After the war, Japan Electric Generation and Transmission was designated for breakup under the Economic Decentralization Act.

The hydroelectric plants around Lake Inawashiro were placed under the management of Tokyo Electric Power Company, Inc., where they remain today.

Tokyo Electric Power Company has adjusted the water level of Akimoto Lake in response to requests from Fukushima Prefecture.

Fukushima Prefecture, alarmed by the rapid river overflow, developed new flood prevention plans for the Inner Bandai tri-lake area.

Due to environmental protection concerns related to the nearby Bandai-Asahi National Park, the construction of levees or dikes was not feasible.

The practice of damming natural lakes for flood prevention and water usage is common nationwide.

Following this, the regulation of water levels, which had previously been managed by Tokyo Electric Power Company, was taken over directly by the Inawashiro office of civil engineering in Fukushima Prefecture.