is in Tokyo and Yamanashi Prefectures in Japan. Lying above the Ogōchi Dam, it is also known as the Ogōchi Reservoir. Lake Okutama is an important source of drinking water for Tokyo. Description The lake occupies part of the town of Okutama in Nishitama District, Tokyo and the village of Tabayama in Kitatsuru District, Yamanashi. The Taba (Tama) River feeds Lake Okutama at its western end. From the southwest, the Kosuge River also flows into the lake. The Tama River drains the lake at the eastern end. The surroundings are famous for cherry blossoms in the spring. Ogōchi Dam Dam height: 148 m Dam length: 353 m Greatest depth: 142 m Mean depth: 43.6 m Circumference when full: 45.37 km Altitude of surface when full: 526.5 m Area of surface when full: 4.25 km² Capacity: 185,400,000 m³ Completion: 1957 Displaced: 945 households Died during construction: 87 people Notes External links Tokyo Metropolitan Government Bureau of Waterworks Japan National Tourism Organization Go Tokyo, Official Tokyo Travel Guide Landforms of Tokyo Reservoirs in Japan Western Tokyo Landforms of Yamanashi Prefecture