Summary: About 10 percent of all electricity produced in the United States is generated by federal and nonfederal hydroelectric power (hydropower) projects. Almost half of the electricity generated by hydropower is produced by federally owned and operated projects, which include dams, reservoirs, stream diversion structures, powerhouses containing turbines driven by falling water, and transmission lines. The Federal Power Act authorizes the Federal Energy Regulatory Commission (FERC) to issue licenses to construct and operate nonfederally owned hydropower projects, including those on federal lands. In this report, GAO assesses one issue--the status of efforts to recover the costs incurred by federal agencies to administer the hydropower program. In essence, for fiscal years 1995 through 1998, federal agencies reported a total of about $32 million in hydropower program-related administrative costs. However, on the basis of its review, GAO estimated that for the 4 fiscal years, about $12 million in federal costs to administer the hydropower program either were not reported or might not be recovered because of appeals by licensees.