Shortly after being relocated to other towns in the late 1980s to make way for Japan's largest dam, about 10 aging former residents defiantly returned to the abandoned village of Tokuyama, in western Gifu Prefecture, determined to live there as long as possible. They sheltered in their old homes or makeshift huts; they tended their vegetable fields, peeling the bark from trees to make all-purpose kampo (medicine); and they caught fish with handmade bamboo traps set in a nearby creek.

Photographer Nobuo Onishi visited the group many times over a period of 15 years, and next week his documentary "Mizu ni Natta Mura (A Village That Changed Into Water)" will be screened in cinemas in Tokyo, Gifu and Nagano prefectures — ahead of the multipurpose Tokuyama dam beginning full operations next spring.

Life in Japan has been closely aligned with dams ever since the nation's first — now known as the Sayama-ike reservoir in Osaka — was built in the seventh century. They serve as a life-saving resource for regions whose people perennially suffer from droughts, and are also a powerful buffer against floods in areas with too much rain. After World War II, dams became a symbol of Japan's economic recovery and industrial prowess, providing water and electricity to the regions they served. In recent decades, however, they have come to represent wasteful expenditure on the part of the government, which critics say is incapable of scaling back or nixing outdated projects. The media have also spotlighted the impact on the lives of people forced from their homes.