Building barrages and dredging the river bed had only a limited effect, and it was almost impossible to improve the river further because of compensation issues, while there were growing calls for fundamental flood control measures, and demand for water was rapidly increasing due to the rapid growth of the population in the Kansai region.
堤防建設や浚渫では限界が出てきており、宅地化の進行でこれ以上の河川改修は補償の観点から難しく、抜本的な治水対策が叫ばれる一方で関西圏地域の人口急増に伴い水需要も引き続き急増していた。