On May 31st, we join together to commemorate National Dam Safety Awareness Day, remembering the lessons learned from past dam failures, pushing for strong dam safety programs, investing in America's critical infrastructure and rededicating ourselves to the effective public-private partnerships that work to keep America's dams safe, operational and resilient.

The issue of dam safety was not widely recognized until 1889 when the failure of South Fork Dam near Johnstown, Pennsylvania claimed more than 2,200 lives. As we observe the 129th anniversary of this tragedy on May 31, we encourage you to know the benefits of dams, your risk, and your role; and, act. Dam safety is a shared responsibility.


Living with Dams

Living with Dams: Know Your Risks, was prepared by ASDSO to help answer questions about dams: what purposes they serve, what risks are associated with dams and where you can get information about how to react if you are affected by one.



A second booklet, Living with Dams: Extreme Rainfall Events, explains the engineering principles involved with predicting extreme rainfall events and how these principles are used to design safe, functional and economical dams. It connects the concepts of rain to floods to dams to failure and the flooding impacts downstream.



Learning About Dams

Water is one of our most precious resources; our lives depend on it. Throughout the history of humankind, people have built dams to maximize use of this vital resource.

There are more than 90,000 dams in the United States and most states are home to hundreds, if not thousands of dams. They are an extremely important part of this nation’s infrastructure—equal in importance to bridges, roads, and airports. They can serve several functions at once, including water supply for domestic, agricultural, industrial, and community use; flood control; recreation; and clean, renewable energy through hydropower.

To learn more about dams, how they work, and how state dam programs are performing overall, visit DamSafety.org/Dams101.


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Buffalo Creek Valley - 1972
Buffalo Creek Valley - 1972
Rapid City - 1972
Rapid City - 1972
Teton - 1976
Teton - 1976
Teton - 1976
Teton - 1976
Laurel Run - 1977
Laurel Run - 1977
Laurel Run - 1977
Laurel Run - 1977
Toccoa Falls - 1977
Toccoa Falls - 1977
Toccoa Falls - 1977
Toccoa Falls - 1977

Knowing Your Risks

Dams are an important part of our water management systems, but when they fail, flooding can be catastrophic and can adversely affect people, their livelihoods, and property. Dam failure floods are almost always more sudden and violent than a normal stream, river or coastal flood. They often produce damage that looks like tornado damage.

The safe operation and proper maintenance of dams is critical to sustaining the benefits while mitigating the risk of a dam failure. As dams age, upgrade and rehabilitation become more vital due to deterioration, changing technical standards and improved techniques; as well as our better understanding of precipitation conditions, increases in downstream populations and changing land use. The average age of our nation’s dams is 56 years old. By 2025, 7 out of 10 dams in the United States will be over 50 years old. Investment is needed to rehabilitate deficient dams, however, many dam owners, especially private dam owners, find it difficult to finance rehabilitation projects.(See the 2016 Cost of Rehabilitation Report)

As of 2016, there are approximately 15,500 dams in the United State that are classified as high-hazard potential, meaning failure of the dam would likely result in loss of life. Another 11,882 dams are labeled as significant-hazard potential, meaning a failure would result in significant economic losses. The number of high-hazard potential and significant-hazard-potential dams is increasing in part due to ‘hazard creep.’ Hazard creep describes the growth of development—buildings, businesses, and people—moving closer to dams that were originally located in agricultural areas. See a video on hazard creep below.

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View all ASDSO YouTube videos


Asking Questions and Taking Action

1. Are there dams near to where you live and work? For state-specific dam safety details, visit the ASDSO state map.

2. Inform your friends and neighbors about the benefits and risks associated with dams.

3. Urge Congress to fund the National Dam Rehabilitation Act.

4. Urge your state to require and exercise Emergency Action Plans, especially for high-hazard potential dams, where loss of life could result should the dam fail.

5. Urge policymakers to enact strong dam safety laws and fully fund state dam safety programs.

6. Urge local zoning restrictions near dams.


Staying Clear of Dams

Each year, dozens of lives are lost at dams on U.S. streams and rivers, many at low-head dams, also known as run-of-river dams or "drowning machines." These structures, generally less than 15 feet high, can create backflow currents and turbulence capable of producing disorientation, hypothermia, exhaustion, and brutal battering. These forces combine to create a practically inescapable circular trap for even the strongest, life jacket-clad swimmer.

Over Under Gone Youtube.png

Video the full version of Over, Under, Gone: The Killer in Our Rivers.


Tips for Low-Head Dam Safety

1. Teach your friends and family about low head dams and other hazards in or near the water.

2. Wear your personal floatation device (PFD).

3. Know the waterway (river or lake).

4. Tell someone where you are going and when you will return.

5. Be aware of changes in water elevation and velocity due to weather events in the past 72+ hours.

6. Stay clear of dams both up and downstream.

7. If someone is in trouble, do NOT enter the water to assist them.  Use a throw bag or other remote assistive device.

More information and resources are available through the ASDSO Public Awareness Page.


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For more information, email Communications Manager Katelyn Riley - kriley@damsafety.org