Ōsako Dam

Overview

Ōsako Dam is a concrete arch dam built at Ōsako in Kawakami Village, Yoshino District, Nara Prefecture, at the very uppermost reach of the main stream of the Kino River. Standing 70.5 metres high with a crest length of 222.3 metres, it supplies water for agriculture, provides drinking water and generates electricity. Cradled deep in the Yoshino mountains, its curving arch and the calm surface of the reservoir make for a striking valley landmark.

Highlights

• ●A concrete arch dam 70.5 m high with a 222.3 m crest
• ●A headwaters site at the uppermost reach of the main Kino River
• ●Views over a reservoir holding about 27.75 million cubic metres
• ●The form of a multipurpose dam for farming, water and power

History

Construction of Ōsako Dam began in 1954 and was completed in 1973. Sited at the headwaters of the main Kino (Yoshino) River, it has a catchment area of about 114.8 square kilometres. At full capacity it floods roughly 107 hectares of land and can store about 27.75 million cubic metres of water. As a multipurpose dam serving agriculture, water supply and power, it has long supported the farmland and daily life of the region.

Map

34.2739, 136.0128 · Wikidata

Suggested itinerary

1. 1Drive up the mountain roads of Yoshino's Kawakami Village to Ōsako Dam
2. 2View the arched dam body, over 70 metres tall, up close
3. 3Take in the reservoir and the ridgelines at the Kino River headwaters
4. 4Explore the surrounding Yoshino nature and Kawakami village afterwards

Did you know?

💡 Ōsako Dam is an arch-type concrete dam that transmits water pressure to the valley walls, rather than a gravity dam. It was a large-scale project that took some twenty years from groundbreaking to completion, and it fills three roles at once — agricultural water, water supply and power generation — at the strategic headwaters of the main Kino River.

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