Asian River Restoration Network (ARRN)

The Asian River Restoration Network was established in Nov. 2006 to support the exchange of information relating to environmental restoration of rivers and watersheds. JRRN has a role of ARRN secretariat currently.

Go to ARRN website

Contact us (Secretariat)

Lofty Chuoh Bldg., 7th Flr.

17-24, Shinkawa 1cho-me, Chuo-ku, Tokyo 104-0033, JAPAN

Foundation for Riverfront Improvement and Restoration
Tel: +81-3-6228-3860
Fax: +81-3-3523-0640


< World's WATERFRONT:JAPAN Category: Water quality Restoration >

Restoration of Nishitakase River (Kyoto City, Kyoto)

Nishitakase River running through Kyoto City was opened as a canal for transportation by water. Later, it was used to discharge the water for textile dyeing such as Kyo Yuzen printing and the color of the river water changed daily and the water quality deterioration was serious.
Under the circumstances, the contamination was reduced and ozone treatment facilities were installed in 1997.Since then the color of the river and foam formation have been improved dramatically and the water environment of this river has greatly recovered. In addition, this river was selected as a "Limpid Stream Renaissance II project river" and because efforts were made to create an environment for water amenities and improve the water quality, a river environment suitable for a stroll in Kyoto has been recovered.

Restoration of Naka River and Ayase River (Tokyo)

For Ayase River, which was recorded as the worst river in terms of water quality for 15 consecutive years, a project was conducted to channel the water of Ara River upstream as part of "Limpid Stream Renaissance II" (a water environment improvement emergency action plan). This project won the Japan Society of Civil Engineers' Environmental Award in 2001 as Japan's first project using the tunnel upper part for subways and the lower part for a river water conduit.

Restoration of Furo River (Kawagoe, Sayama, Tokorozawa and Iruma Cities and Mizuho Town, Saitama Prefecture)

Furo River, running through Saitama Prefecture, was once called "Toshitorazu (meaning unaging) River" because the main water source was a spring that dried up in winter and the flowing water did not see the old year out.. However, a large quantity of living drainage was discharged into the river due to the population increase in the basin and the river was named the most contaminated river in Japan and such a disgraceful situation was continued in the past..
Now, the"basin sewage project for Furo River water quality environment conservation measures" are being conducted to recover the water environment by resolving the sewage-treated water into Furo River. Moreover, efforts are being made to conserve and regenerate the water environment through water environment improvement projects such as "Limpid Stream Renaissance 21" and "Limpid Stream Renaissance II".

Restoration of Yanase River (Tokorozawa, Higashimurayama, Kiyose, Niiza and Shiki Cities, Saitama Prefecture)

Concerning Yanase River, a tributary stream of Shingashi River, running through Saitama Prefecture, the water quality was extremely deteriorated in the decade starting in 1975 because of the rapid increase of the population during the high-growth period. However, the water quality has been improved gradually as a result of the construction of a sewage system. In 2006, a river environment improvement project was started based on the “Yanase River basin water circulation master plan”. To solve water problems related to river conservation, water utilization and the water environment, river restoration activities are being conducted under cross-sectional cooperation of not only the river administrator but also the administrative agencies concerned.

Restoration of Komaki River (Sakata City, Yamagata Prefecture)

In Komaki River, the water quality was deteriorated by urbanization and the river was named the "dirtiest river in Yamagata Prefecture" each year from 1996 to 1999. People in this area suffered from the serious deterioration of the water environment.
Under the circumstances, local residents voluntarily established "a group to clean up the Komaki River of Sakata City" and are conducting purification activities earnestly. As an approach to utilize the existing agricultural water and the agricultural facilities to improve the waterfront environment, a project to flow the purified water (ambient water) from Mogami River to Komaki River by changing the place where agricultural water is discharged started in 2007 for the first time in Japan. Thus the water quality has been improved.

Restoration of Ibo River (Tatsuno City and Himeji City, Hyogo Prefecture)

Ibo River in Hyogo Prefecture flowing into Seto Inland Sea had a poor record: it was designated as the 3rd- to 5th-worst river in Japan in terms of water quality because the wastewater was discharged from households and the local industries such as leather product makers.
Under the circumstances, construction of a sewage system was promoted in the Ibo River Basin and the sewage system penetration rate was improved. In addition, the whole quantity of the leather makers' wastewater has been accepted by the water treatment facilities since 1994. As a result, Ibo River made rapid progress in recovery and gained the 2nd-best place in water quality in the Kinki region in the following year. It was also designated as one of the "100 revived waters". Today, the ascent of natural plecoglossus altivelis was observed for the first time in 40 years and the recovery of a clean stream of Ibo River was welcomed by local people. A fishing contest and river-rafting held by a local group is becoming popular year by year and the connection between the local community and the river has been revived.

Restoration of Sana River (Toyokawa City, Hoi County Kozakai Town and Toyohasi City Aichi Prefecture)

Sana River running through the eastern Mikawa area of Aichi Prefecture became so contaminated that the BOD was 60 mg/l, which was measured at the environmental basing point located downstream in 1978. This was because of the urbanization in the peripheral area that occurred during the decade starting in 1965. However, the construction of the sewage system was started in Toyo River Basin including Sana River Basin in 1980 and since then the water quality has been largely improved along with the progress of the sewage system improvement.
Today, children playing with water can be seen and a project to change the dike into a flower corridor is being promoted by community residents. Also, this river has been selected as one of the "100 revived waters", thus it is being changed into a river cherished by the local people.

Restoration of Fushimi and Takahashi River (Kanazawa City, Ishikawa Prefecture)

In Fushimi and Takahashi Rivers running in the southern part of Kanazawa City, a serious problem of water quality deterioration was caused by the rapid urbanization of the surrounding areas. The water quality was such that the BOD exceeded 10 mg/l but it was improved to approximately 3 mg/l by the construction of a sewage system that started in 1976.
Today, the ascent of salmon is seen and the former clear stream has been revived. The "river festival" is held by the local people and the river space has become a place for recreation and relaxation for citizens.
Fushimi and Takahashi Rivers were recognized as rivers in which the water environment was conserved and recovered by the sewage system and designated as one the "100 revived waters."