The project was launched by the Economic Stabilization Bureau in 1947 following Typhoon Kathleen in September 1947 (which killed 1547 people).

The need for a dam primarily for flood control was emphasized by Typhoon Ione in September of the following year, which killed an additional 1956 people.

The project was complicated by the extreme acidity of the water (reaching pH of 4.0) due to runoff from the Matsuo mine upstream.

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