Description & Background


Trees along embankment crest create concentrated flow that can cause erosion of grass and soils surrounding them during overtopping of dam. Vegetation at and around dams can impact dam performance and lead to failure.

Regular operation and maintenance as well as thorough and consistent inspection must be practiced throughout the lifetime of a dam.  In addition to maintaining proper function, cost efficiency, and compliance with safety regulations, such habits can lead to the early detection of deficiencies and prevention of failure.  Continuing these management activities is a simple way to extend the useful life of a dam provided a detailed Operations and Maintenance (O&M) Program that includes routine, adequate inspections has been developed and is followed.

An O&M Plan is a unique guidance document developed to ensure that a dam is performing safely and according to its design and purpose.  As the name suggests, this type of program contains details pertaining to two main administrative matters:  operation and maintenance.  The first portion of an O&M Plan consists of a series of procedures that are essential to proper dam operation and often extracted from a Standard Operating Procedures (SOPs) report or a similar type of manual.  This section of an O&M Plan may also contain managerial practices to guarantee and document the completion of the SOPs.

While the first part of an O&M Plan is devoted to dam operations, the second focuses on facility upkeep.  Standard practices for both preventive and extraordinary maintenance should be provided in this section.  Preventative maintenance is performed routinely and includes the servicing of the dam and its appurtenances with the intention of avoiding over-vegetation, animal impacts, equipment deterioration, mechanical malfunction, flooding, or failure.  Extraordinary maintenance is comprised of the repairs required to correct these damages if they do occur.

In addition to consistent and documented operation and maintenance, regular inspection is essential to preserving the proper functionality of a dam.  Formal dam safety inspections and routine assessments should be conducted regularly.  Dam assessments are thorough investigations of a dam by licensed professionals in which design documents are consulted and the current conditions are compared to those considered state-of-the-art.  Inspections are conducted on a more frequent basis by dam operators or maintenance personnel.  These inspections include simple observation of the dam, appurtenances, the reservoir, and surrounding area.

With the implementation of consistent operation, maintenance, and inspection comes a record of baseline conditions at the dam.  As a result, deviation from normalcy becomes apparent. Because signs of potential risk and failure often present themselves prior to a disaster, early detection of such issues through proper O&M and inspection is essential.  Early detection of potential dam incidents provides crucial time for the appropriate response to be executed.  When performed according to O&M documents and immediately following an unusual observation, these two actions can lead to the prevention of dam failure and its consequences.


(1) USBR.  (1990).  Training Aids for Dam Safety:  How to Organize an Operation and Maintenance Program.  Denver:  U.S. Department of Interior, Bureau of Reclamation.






Case Studies

Baldwin Hills Dam (California, 1963)

The Baldwin Hills Reservoir was constructed in 1951 to provide water to the south and southwest portions of the city of Los Angeles, California. Sitting atop one of the tallest hills in the region, the reservoir was confined on three sides by compacted earth dikes...

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Big Bay Lake Dam (Mississippi, 2004)

A number of the site conditions, design and construction details, and the distress indicators that developed between the initial reservoir filling and failure combine to suggest a complex internal erosion...

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Canyon Lake Dam (South Dakota, 1972)

The Friday afternoon of June 9, 1972 was the beginning of a tragedy for Rapid City, South Dakota along the eastern slopes of the Black Hills mountain range. Scattered showers from the previous days had left the ground saturated while a low-level air mass...

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Folsom Dam (California, 1995)

Located approximately 20 miles northeast of Sacramento, California, Folsom Dam was designed and constructed by the U.S. Army Corps of Engineers to generate hydropower along the American River. The 340-foot high concrete gravity Folsom Dam along with two earthen wing dikes...

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Kelly Barnes Dam (Georgia, 1977)

Kelly Barnes Dam was located approximately a half mile upstream (north) of Toccoa Falls Bible College in Stephens County, Georgia. Toccoa Falls, a 186-foot-high waterfall, was located between the dam and the college. The dam site was originally the location...

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Lake Delhi Dam (Iowa, 2010)

Lake Delhi Dam was originally constructed by the Interstate Power Company between 1922 and 1929 for hydroelectric power generation. The dam is located in Iowa approximately 1.4 miles south of Delhi on the Maquoketa River and impounds the nine-mile-long Lake Delhi. Reaching a maximum height...

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Laurel Run Dam (Pennsylvania, 1977)

Constructed between 1915 and 1918, Laurel Run Dam was a rockfill dam erected across Laurel Run near Johnstown, Pennsylvania. It was built to replace a smaller dam in order to provide water for drinking and industrial needs...

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Penn Forest Dam (Pennsylvania, 1994)

Penn Forest Dam was constructed between 1956 and 1958 to be one of the main water supply reservoirs for the city of Bethlehem, Pennsylvania. The dam was originally an earthfill embankment structure, stood 145 feet high, 1,930 feet long, and stored 6.4 billion gallons of water...

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South Fork Dam (Pennsylvania, 1889)

South Fork Dam was an earth- and rock-fill dam located about 8 miles east of Johnstown, PA. Originally constructed in 1852, the dam’s primary purpose was to provide a source of water for a division of the Pennsylvania Canal. The dam was approximately 72 feet high...

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St. Francis Dam (California, 1928)

Located approximately forty miles northwest of Los Angeles, California, St. Francis Dam was a curved concrete gravity dam constructed between 1924 and 1926 in order to provide a storage reservoir for the Los Angeles Aqueduct system...

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Additional Case Studies (Not Yet Developed)

  1. Black Creek Site 53 (Mississippi, 1983)
  2. Buffalo Creek Coal Waste Dam (West Virginia, 1972)
  3. Centennial Narrows Dam (Arizona, 1997)
  4. Ka Loko Dam (Hawaii, 2006)
  5. Lake Needwood Dam (Maryland, 2006)
  6. Lawn Lake Dam (Colorado, 1982)

Best Practices

The National Dam Safety Program: Model State Dam Safety Program

Author: Federal Emergency Management Agency
Date Published: 2007

Technical Manual for Dam Owners: Impacts of Animals on Earthen Dams

Author: Federal Emergency Management Agency
Date Published: 2005

Technical Manual for Dam Owners: Impacts of Plants on Earthen Dams

Author: Federal Emergency Management Agency
Date Published: 2005

Training Aids for Dam Safety: Inspection of Embankment Dams

Author: Interagency Committee on Dam Safety

Training Aids for Dam Safety: Dam Safety Awareness

Author: Interagency Committee on Dam Safety

Evaluation and Monitoring of Seepage and Internal Erosion

Author: Interagency Committee on Dam Safety
Date Published: 2015

Other Resources

Structural Condition Assessment of Dam Facilities with Non-Destructive Evaluation

Author: L. Olson

Webinar published by Association of State Dam Safety Officials

Maintenance and Operation of Dams to Prevent Failure

Author: P. Rizzo & J. Blair

Technical Paper published by Association of State Dam Safety Officials

Introduction to Inspecting Dams for Owners and Operators

Author: P. Schweiger

Webinar published by Association of State Dam Safety Officials

Developing Operation and Maintenance Manuals for Dams

Author: S. Jamieson

Webinar published by Association of State Dam Safety Officials

Recommended Guidelines for Safety Inspection of Dams, ER 1110-2-106

Author: U.S. Army Corps of Engineers

Engineering Report for USACE

Pocket Safety Guide for Dams and Impoundments

Author: U.S. Department of Agriculture

Instructional guide