During the 1990s, DOE identified more than 5,600 specific sites in the United States with undeveloped hydropower resources totaling about 30,000 MW of electricity-generating potential. These sites are identified in individual state resource assessments.
Another DOE study, published in 2004, estimated that total untapped hydropower potential in the contiguous 48 states is about 160,000 MW. This is a theoretical maximum based on calculating the energy contained in flowing water in streams across the country, and no feasibility assessments have been performed to determine the practicality of capturing this energy. But the study is interesting precisely because it identifies all watercourses with untapped hydropower resources, so it's a good place to start when trying to determine if you have hydropower potential in your area.
The 2004 study (PDF 3.6 MB), covers all hydropower resources, with a focus on low head (less than 30 feet) and low power (less than 1 MW) resources, which make up about 19,000 MW of the total available potential. Microhydro sites, defined as sites with less than 100 kW of hydropower potential, make up about 9,500 MW of these low head and low power resources. Microhydro sites are abundant and exist everywhere in the country except in the plains from North Dakota to the Texas panhandle (see map below). Download Adobe Reader.
For more information about hydropower resources, pursue one of the following links:
State-by-state resource assessments — Detailed hydropower resource assessments for 49 states. No report was generated for Delaware because of scarce hydropower resources in that state.
Tribe-specific maps — Detailed tribal maps based on DOE's April 2004 resource maps.