Kyuosatunuma is a farm drainage that is 2 km long and 130 m wide, located at the border of Chitose City and Naganuma Town, and flows into the Chitosegawa river. The whole area was the vast swampland before, with the name of Osatsunuma. But the drainage works have formed the present appearance. The water is shallow and Zizania latifolis and Trapa japonica are distributed. At the southwest side there is a 30ha grassland, mostly of Phragmites australis and Solidago virgaurea var. asiatica. It is surrounded by Salix (myrtilloides), Sambucus racemosa ssp. and windbreak forests of Betula platyphylla var. japonica and Fraxinus mandshurica. Surrounding farms rotate crops of wheat, beans, sugar beet and other vegetables.