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Ayumi of Yokohama water supply (summary)

Final update date March 22, 2019

History of Yokohama Channel

1. Establishment of modern water supply

After the opening of the port, the population of Yokohama, which was a cold village with only 100 units, increased day by day, and the city developed rapidly. At that time, residents dug wells in search of water, but Yokohama was not blessed with high quality water because it reclaimed and expanded the sea, and most well water contained salt and was not suitable for drinking water. For this reason, the governor of Kanagawa Prefecture welcomed British engineer Henry Spencer Palmer as an advisor, and in 1885, built a water source at Mitsui (currently Mitsui, Midori-ku, Sagamihara City) at the junction of the Sagami River and Doshikawa. Started and started supplying water as Japan's first modern water supply in October 1887.
At the start of water supply, there was no law on water supply, and the water supply business was operated by Kanagawa Prefecture. Later, the municipal organization was enacted in April 1889, and Yokohama City was born. In 1890, the first water ordinance was enacted in Japan as a water supply law. Along with this, the water supply business was managed by the municipalities, and was transferred to Yokohama City in April of the same year and started to be operated as a municipal government.

2 The first and second expansions

In 1890, when the water supply business was transferred to Yokohama, the population of Yokohama reached 120,000 (water supply population of 90,000), far exceeding the original plan (water supply population of 70,000), and the population increased. . In order to respond to this, the water intake point was moved to Doshikawa in 1897, and the first expansion work was carried out from 1898 to 1901 to build the Kawai Water Purification Plant. Since then, the population has increased with the expansion of the city area, and the demand for industrial water has rapidly increased in the wake of the Russo-Japanese War. In the second expansion work, the Nishiya Water Purification Plant was completed in 1915. In 1916, we purchased a forest in Doshimura, Yamanashi Prefecture, and started managing and preserving it as a water source forest to maintain the water quality of Doshikawa, a water source.

3 Damage caused by the Great Kanto Earthquake and the Pacific War

After two expansion works, the Yokohama Waterworks responded to the increasing demand for water, but the Great Kanto Earthquake that hit the Kanto region on September 1, 1923 caused a catastrophic impact on the facilities. Received Immediately after the earthquake, we carried out transportation water supply and emergency restoration, and then started reconstruction work and worked on reconstruction after the earthquake. In addition, in order to cope with the increase in water supply due to reconstruction, we have been implementing water-saving measures, such as conducting water leakage surveys and shifting water usage to a full-family measurement system.
In addition, Yokohama City was again severely damaged by the air raid following the Pacific War that began in 1941. At the end of the war, the population served by water dropped from 755,000 to 220,000 before the war, and the number of water supply units dropped from 155,000 to 47,000, causing severe damage to government buildings and water supply facilities.

Responding to the recovery after the 4th war and the increase in water demand during the period of high economic growth

In addition to the population growth associated with the post-war industrial development, the standard of living has improved, such as the rapid spread of washing machines, private baths, and flush toilets, and the demand for water has increased significantly. In order to respond to this, the 5th expansion work (1956 to 1961) to the 8th expansion work (1971 to 1980) was carried out one after another, and the construction of the Tsurugamine water purification plant and the Kojaku water purification plant, and the Nishitani water purification plant Was strengthened. At the same time, new water sources such as the Sagami Dam and Shiroyama Dam were also developed.

5 Full-scale operation of Miyagase Dam

With the eight expansion works and the full-scale operation of the Miyagase Dam in 2001 (2001), water sources and facilities that can provide stable water supply in the future have been established. After the era of “maintenance and management” of facilities and other facilities that were developed during the expansion era, the renewal of aging facilities, earthquake resistance in preparation for large-scale earthquakes, and the optimization of the scale of water supply facilities due to a decrease in water demand are now being carried out. The importance of "renewal and rebuilding" is increasing.
In 2014, the Kawai Water Purification Plant, the oldest in the city, was redeveloped into the largest membrane filtration water purification plant in Japan utilizing natural energy, and the Tsurugamine Water Purification Plant was abolished. Currently, we are rebuilding the Nishitani water purification plant.
The Yokohama Water Supply will continue to maintain and manage facilities such as three water purification plants in the city and approximately 9,200 km of water pipes on a daily basis, and will stably deliver safe and high-quality water to customers 24 hours a day, 365 days a year.

For inquiries about water supply, please contact Water Works Bureau Customer Service Center.

Water Works Bureau Customer Service Center

Telephone: 045-847-6262 Fax: 045-848-4281
※Please be careful not to make a mistake.

Inquiries to this page

Water Works Bureau General Affairs Division, General Affairs Department

Telephone: 045-671-3105

Telephone: 045-671-3105

Fax: 045-212-1155

Email address: [email protected]

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