a river in Poland, right-hand tributary of the Oder. Length, 808 km; basin area, 53,700 sq km.
The Warta rises in the Malopolska Upland. It cuts through the Kraków-Częstochowa Upland and, after coming out onto the Wielkopolski Lowland, at first flows north through a narrow valley. At the city of Kolo it turns west, in certain individual sections taking advantage of ancient hollows, created by the flow of glacial waters. The river has a high-water period during spring (March-April), as well as floods during summer and autumn. Ice jams do not occur every year. The average annual discharge of water is 215 eu m per sec. Over a length of 350 km the Warta is regulated by locks. It is navigable up to the city of Poznan, and for smaller boats up to the mouth of its left-hand tributary, the Prosna. Through its navigable tributary, the Noteć, the Warta is linked by means of the Bydgoszcz Canal with the basin of the Vistula River. Located along the Warta are the cities of Częstochowa, Poznan, and Gorzów (Wielkopolski).