Lake Okutama
Lake Okutama
Coordinates	35°47′N 139°02′E / 35.783°N 139.033°E / 35.783; 139.033
Lake type	reservoir
Primary inflows	Tama River, Kosuge River
Primary outflows	Tama River
Basin countries	Japan
Surface area	4.25 km2 (1.64 sq mi)
Max. depth	142 m (466 ft)
Surface elevation	526.5 m (1,727 ft)

Lake Okutama (奥多摩湖, Okutama-ko) 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.^[1]

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