Together with the Sunpu-jo Castle lord Kazuuji NAKAMURA, who ruled the land across the river, Katsutoyo constructed dikes and changed the flow of the Oi River, which frequently caused floods.
更に洪水の多かった大井川の堤防の建設や流路の変更を川向いを領する駿府城主・中村一氏とともに行っている。