The Ogouchi Reservoir, serviced by the museum, is one of the largest water supply reservoirs in Japan.
Construction of the Ogouchi Dam was interrupted by World War II, causing the project to span from 1938 to 1957.
The reservoir area covers approximately 4.25 square kilometers.
The facility is operated by the Bureau of Waterworks of the Tokyo Metropolitan Government.
The museum documents the relocation of 945 households required to create the reservoir.
The Okutama Water and Green Museum serves as the primary educational facility regarding the Ogouchi Dam and the Tokyo Metropolitan Government's water supply system. Located directly adjacent to the Ogouchi Dam, the museum focuses on the history of the reservoir’s construction and the preservation of the surrounding forest ecosystem. Exhibits detail the technical engineering required to supply Tokyo with water from the Tama River basin. Visitors can view a 3D model of the dam and surrounding topography to understand the scale of the watershed. The facility acts as an information hub for the Okutama area’s natural heritage and conservation efforts. It provides a historical account of the local villages submerged during the reservoir's creation in the 1950s.
The observation deck overlooking the Ogouchi Dam and the expanse of Lake Okutama.
Combine your visit with a walk along the top of the Ogouchi Dam for panoramic views.
Check the museum's official website for temporary closures due to maintenance or weather before traveling.
Bring walking shoes, as the museum is connected to several scenic hiking trails in the Chichibu-Tama-Kai National Park.
Do not rely on mobile GPS for remote mountain trail conditions; check the museum's information desk for local mountain safety updates.
Closed on Wednesdays. If a public holiday falls on a Wednesday, the facility is closed the following day.
