The left side of the Oi-gawa (Hozu-gawa) River where Umaji-cho, Chitose-cho, Kawarabayashi-cho and Asahi-cho are located is called Kawa-higashi and is an alluvial fan of the Atago mountain range; the Nanatani-gawa and Mitsumata-gawa Rivers, taking water from the range, are steep and said to have been frequently flooded.
馬路・千歳・河原林・旭の各町がある大堰川（保津川）左岸は総称して川東と呼ばれ、愛宕山系の扇状地であり、同山系を水源とする七谷川や三俣川は高低差が激しく、よく氾濫したという。