Misplaced Pages

Rivers in Japan are classified according to criteria set by the River Act (河川法, Kasen Hō), which was introduced in 1967. Rivers are classified by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT).

River Act

Pre-1967 river administration

At the beginning of the Meiji era, river construction mainly consisted of low water construction such as securing water for boat transportation and irrigation, but after the middle of the Meiji era, boat transportation declined with the spread of railways, and on the other hand, development of river coasts exacerbated damage from floods. As the number of floods increased, a shift was made to high water construction to prevent flooding by building levees.

The old system was enacted in 1891 following the proclamation of the Meiji Constitution. As Japan's first modern public property management system, a systematic legal system for river management was established. However, due to the background of its enactment, the old River Law had strong overtones of control by state power, and, reflecting the social situation at the time, placed more emphasis on flood control than water utilization.

New River Act

Over the following 70 years, due to post-war social and economic development, the use of river water for hydroelectric power generation and industrial water increased rapidly and because of inconsistencies that had arisen in the system implemented by the old River Act, the new River Act was enacted in 1962, with the following changes:

• All rivers and river systems are classified into four classes
• Entities in charge of rivers are required to formulate a plan for integrated water management
• Establishment of regulations related to water use
• Establishment of regulations to prevent disasters caused by dams

1997 amendment

The River Act was amended in 1997, changing its text to have a greater emphasis on conservation of natural environments, and the consultation and participation of local residents in forming water management plans.

Impact

The 1967 River Act simplified the management of waterways in Japan by merging previously separate systems into one unified water management system. Before this, the river management system in Japan was seen as heavy-handed and overly bureaucratic. Especially post-1997 amendment, there is now greater community involvement when formulating plans regarding rivers and water management.

Class A rivers

Class A river system (一級水系, Ikkyū suikei) is a designation applied to rivers systems deemed to be important to the economy of the nation as a whole, as well as those deemed important to the conservation of nature within Japan. There are currently 109 river systems with this designation. If a river system is designated Class A, all the constituent rivers are also designated as such. Therefore, Class B rivers cannot coexist with Class A rivers in the same river system. This designation is also called First Class.

Class A river (一級河川, Ikkyū kasen) is a designation which applies to important individual rivers. There are 13,994 rivers with this designation.

Generally speaking, areas surrounding Class A rivers will suffer greater damage in the event of a flood.

List of Class A river systems

The number of dams only includes existing and unestablished dams that meet the criteria (15 metres (49 ft) or more in bank height) of the River Law. The management entity is irrelevant. The number in parentheses is the number of dams on the main river, excluding tributaries. The number of dams does not always exceed the number of hydroelectric plants because plants with intake weirs less than 15 metres (49 ft) high are not considered dams. The acronym BOD refers to biochemical oxygen demand.

Note: Okinawa has no Class A rivers.

Hokkaidō Development Bureau

Tōhoku Development Bureau

Kantō Development Bureau

Hokuriku Development Bureau

Chūbu Development Bureau

Kinki Development Bureau

Chūgoku Development Bureau

Shikoku Development Bureau

Kyūshū Development Bureau

Class B rivers

Smaller or less important rivers are designated as Class B river systems (二級水系, Nikyū Suikei). They are nominated and managed by the local governments at the prefecture level, but reported to and concurred with by the central government. There are 7,090 rivers with this designation. Because all of their river systems are designated Class A, there are no Class B rivers in Saitama and Shiga prefectures.

This designation is also called Second Class.

Mutatis mutandis rivers

14,314 rivers in Japan are designated as mutatis mutandis rivers (準用河川, Junyō kasen), meaning that they are not assigned Class A or B designation, and are under the control of the mayor of the encompassing municipality. An example of this is the Kuno River, managed by the mayor of Odawara.

Ordinary rivers

Rivers that are not designated Class A, Class B, or mutatis mutandis, are called ordinary rivers (普通河川, Futsū kasen), and the 1967 River Act does not apply to them. These do not include public sewers or agricultural canals. Management of these rivers is carried out by the local municipality.

See also

• List of rivers of Japan
• Natural disasters in Japan § Floods

References

1. ^ "River Administration in Japan". Ministry of Land, Infrastructure, Transport and Tourism. Retrieved December 31, 2017.
2. "河川法" [River Law] (in Japanese). Ministry of Land, Infrastructure, Transport and Tourism. Archived from the original on June 23, 2016. Retrieved July 6, 2016.
3. ^ "社会経済の変化を踏まえた今後の河川制度のあり方について". Ministry of Land, Infrastructure, Transport, and Tourism. Retrieved 2024-03-05.
4. ^ Sakamoto, Takaaki; Shinozaki, Yui; Sato, Hirokazu; Shirakawa, Naoki; Kayaba, Yuichi (2018-06-13). "IMPACT ASSESSMENT OF THE 1997 REVISED RIVER LAW ON CITIZEN PARTICIPATION IN THE ENVIRONMENTAL POLICIES OF RIVERS". Advances in River Engineering. 24 – via J-STAGE.
5. ^ "川づくりの来し方・行く末 ─ 河川法制定120周年に寄せて". Journal of Water and Environmental Issues. 2015-10-29. Retrieved 2024-03-05.
6. "河川法第四条第一項の水系を指定する政令" [River Law Clause 4 Paragraph 1: River System Designation Ordinance] (in Japanese). e-Gov.go.jp. Archived from the original on March 5, 2016. Retrieved July 6, 2016.
7. ^ "よくある質問とその回答". Ministry of Land, Infrastructure, Transport, and Tourism. Retrieved 2024-03-05.
8. ^ "小田原市 | 1級河川、2級河川、準用河川、普通河川とは何ですか。". 小田原市 (in Japanese). Retrieved 2024-03-05.
9. "普通河川とは？｜株式Rise". 株式会社Rise (in Japanese). Retrieved 2024-03-05.
10. "普通河川". www.thr.mlit.go.jp. Retrieved 2024-03-05.

v t e River systems and rivers of Japan
Rivers of Hokkaido Sea of Japan Ishikari River Chitose River Toyohira River Makomanai River Anano River Yūbari River Koetoi River Rumoi River Shiribeshi-Toshibetsu River Shiribetsu River Teshio River Zenibako River Sea of Okhotsk Abashiri River Shibetsu River Shokotsu River Tokoro River Yūbetsu River Pacific Ocean Akan River Kushiro River Mitsuishi River Mu River Niikappu River Saru River Shizunai River Tokachi River Rivers of Hokkaido on Commons
Rivers of Honshu Tōhoku region Abukuma River Arakawa River Iwaki River Kitakami River Komagome River Koyoshi River Mabechi River Mogami River Natori River Ōhata River Oirase River Omono River Takase River Yoneshiro River Kantō region Arakawa River Edo River Fuji River Kanda River Kuji River Naka River Sagami River Sumida River Tama River Tone River Tsurumi River Chūbu region Agano River Shinano River Seki River Hime River Kurobe River Jōganji River Jinzū River Shō River Oyabe River Tedori River Kuzuryū River Fuji River Abe River Ōi River Sakawa River Tenryū River Toyo River Yahagi River Shōnai River Kiso Three Rivers Kiso River Nagara River Ibi River Kushida River Miya River Kita River Minami River Kansai region Choshi River Ibo River Kako River Kinokawa River Kumano River Kuzuryu River Maruyama River Muko River Yamato River Yodo River Yasu River Katsura River Kamo River Kizu River Dōton River Yura River Chūgoku region Asahi River Ashida River Gōnokawa River Hino River Hii River Ōta River Oze River Saba River Sendai River Takahashi River Takatsu River Tenjin River Yoshii River
Rivers of Shikoku Aibiki River Shimanto River Shinmachi River Suketō River Tamiya River Sako River Sumiyoshijima River Yoshino River Dōzan River Niyodo River
Rivers of Kyushu Kyushu Arie River Chikugo River Kikuchi River Kuma River Mimi River Ōno River Ōyodo River Yaeyama Islands Kokuba River Nakama River Urauchi River
Rivers of Japan Category Rivers of Japan on Commons

• Environmental law in Japan
• Rivers of Japan