EDITORIAL: Yanba Dam project

Last week, infrastructure minister Sumio Mabuchi said he will never again refer to a policy of canceling construction of the Yanba Dam, promising to examine the project without prejudgment. He made the statement after inspecting the dam's construction site in Gunma Prefecture.

With this declaration, he probably aimed to ensure that the review of the project by his ministry and six prefectures concerned, which started last month, will go smoothly.

He stressed his neutral stance toward the issue, which stands in contrast with the vow of his predecessor, Seiji Maehara, to maintain the policy of scrapping the project while studying it.

Mabuchi took a step in the right direction as minister in charge of assessing the project.

Maehara incurred the wrath of the local communities and prefectures concerned by unilaterally proclaiming the cancellation of the long-running project even though the ruling Democratic Party of Japan's manifesto for last year's general election advocated scrapping it. We think Mabuchi doesn't have to follow Maehara.

The lesson to be learned from the political confusion over the dam since last year is that changing such a mammoth project requires careful effort to build consensus.

Policymakers should not ignore the feelings of local residents who, after half a century of persuasion, consented to the construction of a dam that will submerge their native villages. Serious consideration should also be given to the sentiment in Tokyo and other prefectures that have been footing part of the bill.

That is not to say that the government should simply return to implementing construction according to the plan.

The government must not betray the citizens who voted for a power transfer last year because of the expectation that the DPJ would change the traditional approach to large-scale public works, which has effectively precluded the cancellation of a project once under way.

There is one question that must be answered through the planned review of the project.

The land ministry once estimated that a great, once-in-two-centuries flood that could swell the Tonegawa river would generate rushing flows of water at a rate of up to 22,000 cubic meters per second. But the document containing this estimate is missing.

The maximum volume flow rate in the past 50 years was less than 10,000 cubic meters per second. Some experts have criticized the estimate for being too high. Others say it doesn't reflect the postwar recovery of the ability of mountains to retain water.

Some have posited that the necessity of the dam would remain unchanged even if the maximum volume flow rate were around 15,000 cubic meters per second.

The ministry should make clear the basic assumptions upon which the new estimate is based, no matter what it may be.

Similar controversies have engulfed other dam projects across the nation, including the Asakawa Dam in Nagano Prefecture.

In reviewing the Yanba Dam plan, a fresh debate is necessary on the basic issues.

Basic questions concerning the dam's water utilization benefits also need to be answered clearly. One is whether a new water resource is really necessary when the population is expected to keep shrinking.

The project has already consumed 70 percent of the estimated 460 billion yen ($5.59 billion) construction cost. Isn't there the possibility of the cost growing further? On what basis does the government claim that reinforcing the embankments would be more costly than building the dam?

If it decides to cancel the project, the government needs a solid plan to rebuild the local communities. Will it buy the land as promised, or support reconstruction of the hot-spring resort in the area?

Meanwhile, construction work continues. The huge, 100-meter-high bridge across the dam lake is almost complete.

Mabuchi has pledged to make the final decision by the time the land ministry submits its fiscal 2012 budget request next fall.

It is time for national debate on the broad issue of how limited fiscal resources should be used to preserve the environment and protect the well-being of the people.

--The Asahi Shimbun, Nov. 11