Author(s): Yoshiyuki Kuraku; Tetsuya Sumi; Yoshitaka Takei
Linked Author(s): Tetsuya Sumi
Keywords: Reservoir; Irrigation network; Redevelopment
Abstract: ‘Sayama-ike’ is the oldest reservoir in Japan which has been providing irrigation network to the Osaka plain from the early 7th century. This reservoir greets the 1400th anniversary in 2016. Up to the present, this reservoir’s dike has been reinforced and heightened repeatedly to increase reservoir capacity depending on the request of irrigation area expansion. There are many reservoirs at downstream area where developing irrigation network. The Sayama-ike plays an important role that is mainly storing and suppling irrigation water to these reservoirs. This network has the unique distribution system from the Sayama-ike as the first stage reservoir to the second and the third ones which is considered to have been already formed in the late 12th century. In the course of the16th to the 17th century, irrigation area of the Sayama-ike became largest amounted to approximately 4,000hectares. Although the number of reservoirs at the downstream area is not clear, the main reservoir counts more than 130 in the early 20th century even though the irrigation area was decreased. In recent years, Sayama-ike has been largely redeveloped to the multi-purpose one by adding a flood control function and changing its name to‘‘the Sayama-ike Dam’’after completion in 2002. This paper shows these history and current challenges for sustainable management.