National Inventory of Dams

"Congress first authorized the U.S. Army Corps of Engineers to inventory dams in the United States with the National Dam Inspection Act (Public Law 92-367) of 1972. The NID was first published in 1975, with a few updates as resources permitted over the next ten years. The Water Resources Development Act of 1986 (P.L. 99-662) authorized the Corps to maintain and periodically publish an updated NID, with re-authorization and a dedicated funding source provided under the Water Resources Development Act of 1996 (P.L. 104-3). The Corps also began close collaboration with the Federal Emergency Management Agency (FEMA) and state regulatory offices to obtain more accurate and complete information. The National Dam Safety and Security Act of 2002 (P.L. 107-310) and the Dam Safety Act of 2006 reauthorized the National Dam Safety Program and included the maintenance and update of the NID by the Corps. Most recently, the NID was reauthorized as part of the Water Resources Reform and Development Act of 2014.

The NID consists of dams meeting at least one of the following criteria;
1) High hazard classification - loss of one human life is likely if the dam fails,
2) Significant hazard classification - possible loss of human life and likely significant property or environmental destruction,
3) Equal or exceed 25 feet in height and exceed 15 acre-feet in storage,
4) Equal or exceed 50 acre-feet storage and exceed 6 feet in height..."

Dams

EPA Releases Reports on Dam Integrity Assessments at 17 Coal Ash Impoundments
"As part of the U.S. Environmental Protection Agency’s ongoing national effort to assess the management of coal combustion residuals, EPA is releasing the final contractor reports assessing the structural integrity of 17 impoundments and similar management units containing coal combustion residuals, commonly referred to as coal ash, at nine facilities. These 17 impoundments have a “high” or “significant” hazard potential rating. A high hazard potential rating is not related to the stability of those impoundments but to the potential for harm should the impoundment fail. A significant hazard potential rating means impoundment failure can cause economic loss, environmental damage, or damage to infrastructure.

The assessments have rated the structural integrity of seven impoundments as “satisfactory,” nine units as “fair,” and one unit as “poor.” None of the units assessed received an “unsatisfactory” rating. According to dam safety experts, only impoundments rated as unsatisfactory pose immediate safety threats.."

HS5.120:D 18/CD
Technical Manual for Dam Owners: Impacts of Plants on Earthern Dams.
U.S. Department of Homeland Security, Federal Emergency Management Agency, September 2005. (CD-Rom)
"The purpose of this Manual is to provide the dam owner, operator, inspector, dam safety regulator, engineer, and consultant with the fundamental understanding and technical knowledge associated with the potential detrimental impacts of tree and woody vegetation growth on the safety of earthen dams. In addition to objectives related to raising the knowledge level of detrimental effects of trees and woody vegetation growth on the safety of earthen dams, the contents will provide the user of this Manual with an understanding of the methods, procedures, and benefits of maintaining a growth of desirable ground covering vegetation on the embankments of earthen dams."