The U.S. Army Corps of Engineers (USACE) is proud to recognize National Hydropower Day, Aug. 24. For more than 140 years, the USACE Hydropower Program has been providing the nation with ready, reliable, and resilient energy. USACE is the largest owner and operator of hydroelectric power plants in the United States, generating more than 25% of the nation’s hydropower and ranking among the nation’s top 10 power producers overall.