The embankment was completed in just 12 days from the start on June 8, which happened to be in the rainy season, and the long-lasting rain swelled the Ashimori-gawa River, developing a lake of 200 ha.
堤防は5月8日(旧暦)の工事着手からわずか12日で完成し、折しも梅雨の時期にあたって降り続いた雨によって足守川が増水して200haもの湖が出現。