This dam had not been for controlling mining pollution, however, after Eiichiro KONDO, a member of the House of Councilors (at that time) enquired at the committee of commerce and industry, it was concluded that 'it is especially important to keep water quality of this dam.'
このダムは鉱毒対策を目的の中に入れていなかったが、参議院議員近藤英一郎（当時）が商工委員会で質問を行った結果、このダムについては「水質保全に特に留意」することとされた経緯がある。