Overview
- On March 18, the Matsuyama District Court rejected claims by 31 downstream residents who sought about ¥540 million from the national government and two municipalities over flooding tied to emergency dam releases in 2018.
- The ruling found the dams were operated under a 1996 rule set tailored to the Hiji River basin and concluded the deluge was an extraordinarily rare 145–285-year event that did not require deviating from those rules.
- The court said municipal evacuation actions were not “manifestly unreasonable,” while noting room for improvement, including critiques of West Iyo and Ozu cities’ timing and clarity.
- During the West Japan Heavy Rain on July 7, 2018, Kanogawa and Nomura dams began emergency releases around 6:20 a.m.; downstream flooding left 8 people dead and damaged more than 3,000 homes.
- Peak discharge reached roughly 3,700 m³/s at Kanogawa Dam and about 1,800 m³/s at Nomura Dam, levels reported at around six times the then-established large-rain release standard; plaintiffs plan to appeal and related suits continue in other courts, including Okayama.