The Democratic Party of Japan's election manifesto calls for a complete review of large public works projects that fail to respond to the needs of the day, specifically calling for a halt to construction of Kawabe Dam in Kumamoto Prefecture and Yanba Dam in Nagano Prefecture.

A year ago the Kumamoto governor called on the government to cancel the Kawabe project. After the DJP won in the Aug. 30 Lower House election, the land and infrastructure ministry postponed a public tender to select a contractor for Yanba Dam construction, which was scheduled to start in October.

Building a dam in the Tone River system was envisaged after Typhoon Kathleen in September 1947 destroyed river embankments and caused more than 1,000 deaths. The first study for Yanba Dam was carried out in 1952. Completion of construction was originally set for 2000, but has now been moved back to 2015. The total cost has more than doubled from the original estimate to ¥460 billion. Of the more than ¥320 billion already spent, Tokyo and five other prefectures have paid ¥146 billion.

Some local residents whose property would be submerged by the dam reservoir strongly opposed the plan, but conditionally accepted it later. Most people in the area have moved to other places and built new lives. So, local residents and the governors of Tokyo and the five prefectures are now upset by the DPJ's move. One of the roles of the dam is to provide a reservoir for the Tokyo region. But demand for water in the region has dropped. In fact, the government in March lowered regional targets for water supplies from the Tone and Arakawa river systems.

The new DPJ-led administration should disclose all relevant information and carefully listen to the opinions of people concerned before making a decision. If it chooses to scrap the dam, it should present convincing data showing the dam to be unnecessary for flood control and water utilization. A thorough explanation is the party's minimum duty to local residents. It should also seek ways to control floods without relying on dams.