Asahi Dam (Gifu) - Asahi Dam’s Turbid Water Problems

Asahi Dam’s Turbid Water Problems

Issues between the construction and administration of Asahi Dam and the local fishing industry were unavoidable. When construction began, the Mashita River Japan Fisheries Cooperative held fishing rights along part of the Hida River, which was previously known as Mashita River upward from the point (Gero City in Kanayama) where it combines with the Maze River. In 1964, under the River Act, the river was renamed the Hida River in all territories that it flows through, which deprived the Japan Fisheries Cooperative of some of its fishing rights. The cooperative was fiercely opposed to the change. They eventually settled for a combination of 12,880,000 yen and the coverage of fees for the construction of a trout breeding facility.

In July 1965, heavy rainfall caused the Hida River water level to rise, and water discharged from Asahi Dam caused long-term water turbidity along the Hida River, heavily affecting the fishing industry. The construction of Takane Dam #1 at the highest reaches of the Hida River, combined with the presence of Asahi Dam, created major problems for and drew the opposition of the Mashita River Japan Fisheries Cooperative. Demanding a quick fix to the turbidity problem, they took a hardline-stance by withdrawing all support for future hydroelectricity generation projects along the Hida River. Following the Hida River bus accident of 1967 (in which two buses fell into the river, killing 104), the turbidity of the river made search and rescue operations difficult; the Mashita River Japan Fisheries Cooperative pointed to Asahi Dam as one of the causes of the turbidity, raising the issue with mass media and creating more social awareness of it.

Chūbu Electric Power resorted to building a surface water intake facility at Asahi Reservoir. The facility selectively takes in water from the relatively clear water at the upper layer of the reservoir, and by discharging it, lowers the turbidity of the water downstream; such facilities are used at many dam lakes. This response brought the fishing cooperative back to the negotiation tables, but issues of compensation went unresolved, leading the fishing cooperative to first take legal measures to block the production of concrete aggregate used in the construction of the dam, and then declare their intention to use force to block further construction of Takane Dam#1.

In reaction to the fishing cooperative’s declarations, Gifu Prefecture stepped in as mediator between the cooperative and Chubu Electric Power, eventually securing a 4,000,000 yen “Asahi Dam Turbidity Compensation” payment that would be added to the original compensation package paid to the cooperative for the construction of Takane Dam#1, bringing the issue to a close.