Low-head dams may seem harmless due to their small size, but they pose a significant and often deadly risk. Dubbed as “drowning machines” by the American Society of Civil Engineers (ASCE), these structures have been responsible for hundreds of fatalities over the years. At first, they may not seem threatening from the surface. But believe it or not, they are one of the most dangerous water hazards in the country.
What Exactly Are Low-Head Dams?
Low-head dams are structures built across rivers and streams to control water flow. They allow water to flow continuously over their top. The result is a deceptively calm surface. They maintain beautifully smooth water surfaces that seem quite safe.
These low-head dams were originally designed to power mills or manage water levels for irrigation. Today, many remain in use, even though they no longer serve their original purpose. With over 13,000 low-head dams across the U.S., these structures are often very difficult to even see, let alone escape.
Why Low-Head Dams Are So Dangerous
Unfortunately, they have a dark side effect that have been well-documented over the years. Below the surface of the water lies a serious drowning danger. When water flows over the dam, it creates a circular, churning current. In turn, this pulls anything caught in its clutches back towards the dam. This “hydraulic” loop is extremely difficult to escape.
In many ways, this acts like a human-made rip current. Even experienced swimmers and rescue personnel often struggle to break free from the intense pressure. Once a victim is caught in the current, there is a serious risk of deadly drowning. The force of the water repeatedly pulls the person under the waves, preventing them from resurfacing. Even worse, the aerated water reduces buoyancy, making it nearly impossible to stay afloat.
One of the most tragic aspects of low-head dams is that they are difficult to see and often appear harmless. This leaves many unsuspecting swimmers and boaters at their mercy. The dangerous combination of invisibility and lethal power has led to their before-mentioned nickname: “drowning machines.”
No Warning Signs
Despite the danger, low-head dams often go unnoticed and unregulated. Many states do not even track the location of these dams. This can be seen on many official water safety maps, where they are frequently not listed. Even fewer states have laws that require owners to install proper signage or safety measures.
In fact, many of these dams are privately owned or considered “orphaned,” meaning their ownership is unclear. Obviously, not knowing who to hold responsible greatly complicates any efforts to improve safety. According to a task force led by Brigham Young University, more than 1,000 deaths have occurred at low-head dams since tracking began. However, due to a lack of official oversight, the real number could be much higher.
Each year, an estimated 50 people die due to low-head dams. Many of the victims are would-be rescuers attempting to save others from drowning in the hydraulic current.
Staying Safe Around Low-Head Dams
The best way to stay safe around low-head dams is to avoid them entirely. Of course, as we’ve seen, this is easier said than done. Boaters, swimmers, and paddlers should research the rivers and waterways they plan to visit. Always be aware of any potential hazards. Signs and maps can provide warnings, but if there are none, it’s critical to remain as alert as possible.
For those who find themselves approaching a low-head dam, turning back is always the safest option. Rescuing someone trapped in a dam’s current is extremely dangerous. Trained rescue teams equipped with specialized gear are much better suited for these situations. In case of trouble, call for help immediately. If none can arrive, do not approach the dam! Instead, practice the principle of “reach or throw, don’t go!”
In addition to personal safety, increasing public awareness about low-head dams can help prevent future tragedies. By understanding the dangers and advocating for better oversight, communities can push for safer waterways. Hopefully, these efforts will help to reduce the number of deaths caused by these surprisingly hidden hazards.
