Nagano Gov. Yasuo Tanaka on Tuesday in effect turned his back on Tokyo's traditional dam-centered flood-control policy by annunciating a new environmental policy against dams.

Nagano Gov. Yasuo Tanaka at a news conference at the prefectural building

"From a long-term perspective, Nagano, located in the center of Japan and with numerous headsprings of rivers, should make every effort to avoid the construction of concrete dams," Tanaka said in a prepared declaration. "Dams impose a heavy burden on the environment. From now on, we should build as few new dams as possible."

Tanaka's latest move forms part of a "dam-free Nagano" approach aimed at establishing a flood-control policy without the construction of more dams in the prefecture.

Tanaka has promoted the review of some ongoing dam projects in the prefecture, and His announcement may stir up controversy on the future course of the country's flood-control policy.