The Japan Water Agency's first dam restoration project has begun in earnest at the Sameura Dam (Kochi Prefecture), which boasts the largest water reservoir in Shikoku. A floating temporary dyke is installed on the upstream side of the embankment, and the embankment is dug from the downstream side with a jumbo drill while maintaining water use. Three exhaust pipes will be added to improve flood control functionality. Total project cost is expected to be around 40 billion yen, with a goal of completion in fiscal year 2028
Complete image (from water system press release material)
Since the dam began operating in 1975, there have been four floods that have exceeded the dam's planned maximum flow. In the restoration project, a new flood control capacity of 17 million cubic meters could be secured by transferring the already implemented water use capacity and introducing a preliminary discharge plan after construction. Obayashi Corporation and Sato Kogyo JV will handle the construction of the additional spillway, while Hitachi Zosen and IHI Infrastructure Construction JV will handle the construction of the temporary dike facility upstream, and Toyokuni Kogyo and Sato Iron Works JV will handle the construction of the additional discharge facility.
