Member Login Menu

Policy Statement 470 - Dam Repair and Rehabilitation


Approved by the Energy, Environment, and Water Policy Committee on February 13, 2017 
Approved by the Public Policy Committee on June 5, 2017 
Adopted by the Board of Direction on July 29, 2017


The American Society of Civil Engineers (ASCE) supports the enactment of federal and state legislation to provide sustainable and dedicated funding sources for repair, rehabilitation, or removal of publicly and privately-owned dams in the United States. ASCE supports full funding for the High Hazard Dam Rehabilitation program created in the Water Infrastructure Improvements for the Nation (WIIN) of 2016.


The average age of the almost 90,580 publicly and privately-owned dams in the National Inventory of Dams is 56 years. Many of these dams were built as low-hazard potential dams protecting undeveloped agricultural land from flooding. With an increasing population and greater development downstream of dams many have been reclassified, the overall number of high-hazard potential dams continues to increase, to more than 15,500 as of 2016. The number of deficient dams is estimated at more than 5,800 which includes more than 2,100 deficient high-hazard potential dams. The Association of State Dam Safety Officials estimates that it will require an investment of more than $21.6 billion to repair these aging, yet critical, high-hazard potential dams.

By 2020 70% of the nation's dams will be more than 50 years old. Fifty years ago, dams were built with the best engineering and construction standards at the time; however, as the scientific and engineering experience has increased, many dams are not able to safely accommodate our current prediction of large floods and earthquakes. Many of these dams were initially constructed using design criteria for low hazard potential dams due to the lack of development downstream of the dam. The U.S. Census Bureau estimates a population increase of 130 million people within the United States by 2050. This population growth will likely move development further into the unpopulated areas downstream of aging dams, increasing the populations at risk and requiring the or reclassifying of many low or significant hazard potential dams as high hazard potential, therefore requiring much higher design standards.


Civil engineers are the principal designers responsible for dam design, repair, modification and modeling the consequences of dam failures. ASCE recognizes the benefits and risks associated with dams. Therefore, ASCE acknowledges the need to provide funds to maintain, repair, rehabilitate, or remove dams in order to continue realizing their benefits and assure public safety.

ASCE Policy Statement 470
First Approved in 1999