There is a growing need to redevelop existing dams by raising the height to increase their reservoir capacity or by drilling openings in the main body to strengthen their discharge capacity, because this approach is faster, has less impact on the environment, and is more inexpensive than constructing a new dam.

However, dam redevelopment involves surveying, designing, and construction at a dam that is still in operation, and so the work is restricted in various ways not encountered when constructing a new dam. The lower the reservoir water level is during the development work, the easier it is to execute this work, but in many cases, the reservoir water must be set at a high level during execution in order to maintain the dam's water supply capability, making it necessary to construct a large cofferdam.

Also, since flood control must continue as normal, large-scale diversion of flood water is performed during the work period. Thus, efficient construction execution requires complex planning.

The Japan Dam Engineering Center is meeting the rising demand for redevelopment by providing technological assistance and preparing execution plans to ensure the reliability of surveying, design, and execution of redevelopment while attaining simple maintenance and dam safety. The JDEC accumulates redevelopment design and execution technologies while preparing for unprecedented large-scale dam redevelopment by carrying out surveys and research to design new redevelopment-related technologies.