a river in Penza Oblast, RSFSR; a left tributary of the Sura River in the Volga River basin. The Uza is 188 km long and drains an area of 5,440 sq km. It rises in Saratov Oblast and flows through the Volga Upland. It is fed mainly by snow. The mean flow rate 38 km from the mouth is 2.1 cu m per sec. The river freezes between late November and December, and the ice breaks up in April. The Uza is used for water supply.