Restoration of Sumida River
Postwar Sumida River waterfront was occupied by factories and warehouses, was deteriorated like a ditch, and wasshunned by people. At the same time, industrial and logistical structure changes sap the area’s vitality as a
production base. But increasing interest in environment headed for the semi-ruined city waterfront and a possibilityof its restoration emerged and city-and-river development started, thus attractive urban area was gradually created.
In Asian nations with worsening river environments, Sumida River, improving after experiencing 50-year
deterioration is a leading example in Asia.

Key to Restoration¾¾

Water quality improvement
Waterfront space restoration and waterfront development (river-walk)Overview of the River
Sumida River branches from Ara River at Iwabuchi, Kita Ward. It unites
with many streams such as Shingashi River, Shakujii River, and Kanda
River, and flows in Tokyo Bay. It flows south to north in the sevenwards in lower-level eastern areas in Tokyo (Kita Ward, Adachi Ward,Arakawa Ward, Sumida Ward, Taitou Ward, Chuo Ward, and Koutou
Ward). Its total length is 23.5 km, its width is about 150 m, and the basin
dimension is 690.3 km2 including upstream Shingashi River. The basin
population almost reaches 6.2 million.
Sumida River’s water quality, though quite polluted in the high-growth
period, has substantially improved by the efforts such as water
purification projects for Sumida River restoration (e.g., construction of afiltering plant in Ukima). The variety and the number of fish, water
birds, and water plants have also started to increase.

SumidaRiverProject Efforts for Restoration【Water quality improvement】
During the high-growth period, Sumida River was badly polluted as it gulped all the surrounding smellypollutants. It was deemed “non-inhabitable for natural life” and shunned by the citizens. Stronger plant
wastewater regulations, purification water from Tone River, and sewage system development have greatly
improved the water quality to about 5 mg/liter, the threshold for fish inhabitation. The next step required isimproving dissolved oxygen (DO) amount to a level good for aquatic life reproduction.
【Waterfront space restoration and waterfront development (river-walk)】
Sakura Bridge was built in 1985, and the high water bank was removed for 150 meters of its upstream anddownstream respectively. At the same time, gentle-slope bank of berm, water terrace (waterfront river-walk),and super bank were developed.
Sumida River Terrace, from Tsukudajima to Ryougokubashi upstream, is a straight walking trail which also
reinforces the riverbank. It has plants and ornaments but no obstacles or traffic lights. It is a relaxation place
for the local people, and is a good walking trail for visitors enjoying the view of the bridge.

Today’s view ofSumida River
Sewage system penetration and water quality
Source: Tokyo Construction Bureau (http://www.kensetsu.metro.tokyo.jp/kasen/kasen03.html#top)“River, People, City – City Development and Effective Use of River” Ed.: Foundation for Riverfront Improvement
and Restoration. Publisher: Sankaido.
Koutou Ward (http://www.koutou.net/kouen/sumida.htm)