Its uppermost course is tortuous with a rocky bed and high banks under luxuriant vegetation. After passing through a narrow gorge and tumbling 60-80 ft (18-24 m) in the rapids of Chunchankatte, the river widens to 900-1,200 ft across the Karnataka plateau. There, its flow is interrupted by a number of anicuts or weirs. At the Krishnaraja Sagara, the Cauvery is joined by two tributaries, the Hemavati and Lakshmantirtha, and dammed for irrigation, forming a 12-sq-mi (31-sq-km) reservoir.
In Karnataka, the river bifurcates twice, forming the sacred islands of Srirangapatnam and Sivasamudram, 50 mi apart. Around Sivasamudram are the scenic Sivasamudram Falls, comprising two series of rapids, Bhar Chukki and Gagana Chukki, plunging 320 ft and reaching a width of 1,000 ft in the rainy season. The falls supply hydroelectric power to Mysore, Bangalore, and the Kolar Gold Fields, more than 100 mi away.