a river in Zhitomir Oblast, Ukrainian SSR, and Gomel’ Oblast, Byelorussian SSR; a right tributary of the Pripiat’ River of the Dnieper River basin. The Ubort’ is 292 km long and drains an area of 5,820 sq km. It flows through Poles’e. The river is fed predominantly by snow. High water occurs from March through May. The mean flow rate 44 km from the mouth is 22.5 cu m per sec. The Ubort’ freezes between November and January and opens up between the second half of February and the first half of April. The river is used for floating timber.