Is there a hydro energy roadmap for the U.S.?
Following a completed resource assessment for 49 states (no report was generated for Delaware because of scarce resources), the DOE has identified 5,677 sites in the U.S. with undeveloped capacity of about 30,000 MW. In comparison, there are about 80,000 MW of hydroelectric generating plants in the United States today. 
The DOE provides the report, in state-specific sections, at their website (http://hydropower.id.doe.gov/resourceassessment/states.shtml).
The site provides a resource assessment by river basin, a listing of all sites, a primary resource assessment PDF report, and a capacity summary for each state, as is depicted in the NY example below:
The following table reflects forecasts for hydropower, per the DOE, EIA "Annual Energy Outlook 2009" report.
Research by Theresa Pipher