Limay River
El Chocón is used to regulate the flow of the Limay River, for irrigation, and for the generation of hydroelectricity. Its power station is the largest hydroelectric power plant in Patagonia, with a capacity of . It was built by the state-owned company Hidronor (Hidroeléctrica Norpatagónica). It started operating in 1973, and achieved full capacity in 1978. In the period 1974–1995 it produced an annual average of . In 1993 it was privatized, with an exploitation concession granted to Hidroeléctrica El Chocón S. A.