The Hata clan is believed to have improved the Katsura-gawa River around the fifth century, but the river is said to have been flooded repeatedly around the riverside in Nishikyo Ward.
秦氏は5世紀頃に桂川の治水工事を行っていたらしいが、西京区の桂川沿岸では洪水がたびたび起こったという。