The Ou River (simplified Chinese: 瓯江; traditional Chinese: 甌江; pinyin: Ōujiāng; literally: "Bowl River") or Oujiang is the second-largest river in the Zhejiang province of eastern China. The river flows 388 kilometers (241 mi) before finally reaching the city of Wenzhou and emptying into the East China Sea, into which it discharges 20.2 billion cubic meters (710×109 cu ft) of water annually. Shen Jiang (慎江; "Cautious River"), Jiang Yongjia (永嘉江), and Wenjiang (温江; "Warm River") are all former names for this river. Ouju, a form of Chinese opera from the city of Wenzhou, derives its name from the Ou River.