Because 188 households in Hiyoshi-cho were to be submerged through the building of this dam, the residents formed 'Hiyoshi Dam Taisakukyogikai Amawaka Domei' (Amawaka Association, Hiyoshi Dam Opposition Movement) in 1961 when the plan to build 'Miyamura Dam' was announced, and they staged an uncompromising opposition movement against the plan involving people of the whole town for twenty-four years until September 1984 when the compensation negotiations were settled.
このダム建設によって日吉町の188世帯が水没する事になり、「宮村ダム」計画発表の1961年に「日吉ダム対策協議会天若同盟」を住民は結成し、以来1984年（昭和59年）9月に補償交渉が妥結するまでの24年間、町を挙げた強固な反対運動を展開した。