Hydropower policy in the United States includes all the laws, rules, regulations, programs and agencies that govern the national hydroelectric industry. Federal policy concerning waterpower developed over considerable time before the advent of electricity, and at times, has changed considerably, as water uses, available scientific technologies and considerations developed to the present day; over this period the priority of different, pre-existing and competing uses for water, flowing water and its energy, as well as for the water itself and competing available sources of energy have changed. Increased population and commercial demands spurred this developmental growth and many of the changes since, and these affect the technology's use today.
Federal policies regarding the national water resources, within which hydropower exists, were already well-established long before modern electricity was known to exist; as such, previous uses and decisions, as well as government policies and agencies affected how hydropower was later developed. Chief among federal agencies was the involvement of the United States Army Corps of Engineers (USACE). While federal policy regarding interstate waters dates to the constitutional landmark decision under the Commerce Clause in 1824, its implementation was initially limited to development of navigation and its safety, among other demands for such internal improvements. Shortly thereafter, with the General Survey Act the USACE took the lead. By the 1850s and increasingly later, flood control was added to the demands for improvements, as well as recognizing the need to investigate and better understand the science involved. Much of these early improvements were legislated and authorized by rivers and harbors legislation and conducted by the Corps. With the advent of the progressive era before the turn of the 20th century, new, different and often competing technical demands were being made for water resource improvements, including irrigation in the western states and demand for the recently developed electric power in all states. Conservation and better utilization of natural resources in a historic relationship, first became topics of concern and consideration for policy at this time.
