Tokuyama Dam in Ibikawa, Gifu Prefecture, provides the nation's biggest water reservoir. Beginning full operation May 5, it is a typical example of wasteful public works. This multipurpose dam for water utilization, flood control and power generation was first proposed in 1957. To build it, all the Tokuyama village residents — about 1,500 — were forced to move. But the benefits are unlikely to justify the project. If anything, the project shows that the central and local governments should be flexible enough to change course by listening to local opinions.

The water volume of the reservoir is about twice that of Lake Hamana in western Shizuoka Prefecture. But demand for water has leveled off since the 1973 oil crisis. The dam supplies 6.6 tons of water per second, much smaller than the originally planned 15 tons. So far, the only plan to use the water is Nagoya city's plan to use 0.7 tons of water per second from fiscal 2015. The output of a hydraulic power plant whose construction starts in fiscal 2009 was cut from the original 400,000 kW to about 150,000 kW.

The dam's construction cost swelled to about ¥335 billion. Of that, the Gifu, Aichi and Mie prefectural governments and the Nagoya city government will shoulder about ¥120 billion. The failure to sell much of the reservoir's water is increasing the financial burden. Meanwhile, many former Tokuyama village residents have suffered because the land on which their new homes were built has subsided.