Tama River

Upper reaches of the Tama from the Sakai Bridge in Okutama

The Tama (Japanese多摩川, Tama -gawa, rarely玉川with the same reading) is a river on the main Japanese island of Honshu. It is 138 km long and has a catchment area of 1,240 km ².

Geography

The Tama rises south of the summit of the Kasatori yama (1953 m) in the Okuchichibu Mountains of Yamanashi Prefecture. Until his entry into the Okutama Lake it bears the name Tabagawa.

From the Okutama Lake it flows located in Tokyo first as a mountain river to the east until it turns into the city Ōme to the southeast. He now runs through the southern part of the Kanto plain, making it one of the most densely populated areas in the world. Below the cities Inagi and Fuchū Tama forms the border between the Tokyo prefecture cities Chōfu and Komae, and the districts of Setagaya and Ōta on the left bank and the Kanagawa Prefecture with the city of Kawasaki on the right bank. Here just before the mouth of the river also Rokugō -gawa (六 郷 川) is called.

It ends in the port area of Tokyo and Kawasaki in Tokyo Bay. In the estuary, is the international airport Tokyo -Haneda.

History

Because of its large gradient of Tama is notorious for its high water since time immemorial. Early bridges fell again to the floods.

During the Edo period, the river served as the defensive line of the Bakufu, which is why 1688-1874 is no bridge crossing the River. The Edo period also the development of a widespread canal system on the middle and lower reaches, the agriculture ( rice cultivation ) and the water supply of the city of Edo was started.

The existing for hundreds of years dikes along the lower reaches were systematically developed starting from the mouth since 1918. 1974 flood devastated parts of the city Komae.

Economic, environmental and social

The period beginning in the Meiji era construction boom in Tokyo metropolitan area led to increased mining of gravel for concrete production in the lower reaches of the Tama. Thus, the riverbed was decreased and the river water was unusable due to the intrusion of sea water. The gravel mining in the lower section of the river was therefore banned in 1936.

The increasing urbanization of the river basin led to an increase of water pollution, which reached its peak in the 1980s.

Today we try to bring flood protection and ecology. So all weirs are now equipped in Tama with fish ways, which allowed the return of lost fish species.

Between Hamura and the mouth of the river dikes extend (partly on one side, sometimes on both sides) largely crossing-free cycling routes.

The long-range flood areas between the dikes serve the recreation and some are designed as parks and sports facilities, but there are also large brownfield sites as refuges for rare wildlife and plants. The Tama thus makes an important contribution to ecological networks.

In the course of reporting on the typhoon Fitow Japanese media reported in September 2007 that approximately 700 homeless people living in the floodplain between the levees.