Low Head Dam Safety
Be Dam Aware
Low head dams are common on rivers, providing a controlled flow within communities. Found on rivers and streams across the country, these dams are small but powerful reminders of America’s industrial and agricultural roots. Typically less than 15 feet tall, these dams were originally built to serve local needs—providing water for irrigation, powering mills and factories, supporting navigation, or maintaining water supplies. Low head dams were originally constructed to serve practical and economic needs during a time when rivers were critical to local industry and agriculture. Today, many of these dams remain in place, outdated and unneeded, even as the industries they once supported have long since moved on or changed.
While low head dams can still serve useful purposes in some areas, they are public safety hazards that have claimed more than 1,400 lives. Low head dams—sometimes called “drowning machines”—can create dangerous, recirculating currents that trap and kill swimmers, paddlers, and rescuers. In addition to safety risks, they block fish migration, starve downstream ecosystems of critical sediment, and disrupt the natural flow of rivers. Across the country, communities are finding common ground in rethinking the future of these outdated structures, which has led to more and more of these structures being removed each year. As we’ve seen in successful dam removals nationwide, when rivers are restored, everyone benefits—from local economies to ecosystems and from recreational users to future generations.
What is a low head dam?
A low head dam is a human-made structure that spans the full width of a river and is designed to allow water to continuously flow over it. These dams are typically less than 25 feet high and don’t provide flood control.
Are low head dams Dangerous?
Lowhead dams are very dangerous. They should be avoided at all costs by river recreators, no matter what the river level is. Low head dams earned the nickname “drowning machines” because they create a recirculating washing machine-like feature at the base of the dam that does not allow people to swim out of it. These features are called hydraulics and they can trap and kill river users. More than 1,400 people have died at low head dams across the country.
When is Low Head DAm Safety awareness Month?
April is designated as Low Head Dam Public Safety Awareness Month to help educate the public about the risks of low head dams and prevent future fatalities. Be Dam Aware! Know where dams are if you are going out on the river. Always get out of the river and walk around the dam if one is coming up.
Low Head Dam Hydraulics
How to identify a
low head dam
A low head dam is a human-made structure that spans the full width of a river and is designed to allow water to continuously flow over it. These dams are typically less than 25 feet high and don’t provide flood control.
The more you know: The Water Resources Development Act of 2024 established a legal definition in 2024: “the term ‘low-head dam’ means a river-wide artificial barrier that generally spans a stream channel, blocking the waterway and creating a backup of water behind the barrier, with a drop off over the wall of not less than 6 inches and not more than 25 feet.”
Low head dams can look different depending on where they are and how old they are.
Click on the pictures below to take a closer look.
Pro tips: Know before you go!
Is there a low head Dam near me?
Not sure if there is a low head dam on your local river? Check to see! You can find a map of low head dams here.
What do I do if I come across a low head dam?
Portage the dam. Portage means to get out of the water and walk around the dam with your boat or watercraft. Make it a point to get to the riverbank sooner than you think you will need to and wait until you are far away from the dam downstream before getting back in the water.
If I am on the river, how do I know if a low head dam is near me?
As you are going downstream, low head dams can be very difficult to see. Pay attention to warning signs on the river banks and buoys as you are going down the river. Low head dams are dangerous to people both upstream and downstream of the dam, so keep your distance at all times. Even if you are downstream of the dam, the strong current can pull you upstream and into the dangerous water. Unfortunately, due to many factors, there are not always adequate warning signs around a low head dam which is why it is extra important to check a map of your river before embarking!
What should I do if someone is caught in a low head dam?
If you see someone caught in a low head dam, call 911 immediately. DO NOT attempt to enter the water to help, you could also become a victim.
Fast facts about low head dams
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Low Head Dams in the Country
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Low Head Dam Fatalities
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Low Head Dams Removed
Low head dam safety awareness month
April is designated as Low Head Dam Public Safety Awareness Month to help educate the public about the risks of low head dams and prevent future fatalities. It is important to Be Dam Aware! Know where dams are if you are going out on the river. Always get out and go around the dam on your way down the river.
Click on and print this handout to bring to your next river community event to help everyone
Be Dam Aware!
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