Okirihata Dam Disaster Recovery Construction Site Visit

The Okirihata Dam in Nishihara, Aso, before being damaged by the 2016 Kumamoto Earthquakes, irrigated 71 hectares of rice fields and 108 hectares of farmland in Nishihara and as well as 135 hectares of farmland in Mashiki. Additionally, it sent winter water to the nearby Fukasako Dam, creating the indirect benefit of irrigating 403 hectares of farmland in Kikuyo. However, the dam was severely damaged in the Kumamoto Earthquakes, including to the main dam body. Post-disaster investigations revealed that there were surface earthquake faults running through the dam body and the dam reservoir. As a result, Kumamoto Prefecture set up the Okirihata Dam Reconstruction Office and is working swiftly to repair the dam. Construction of the main embankment began in August 2023, and currently embankment fill work, spillway construction, and other construction work continues aimed at resuming operations in FY2026.