What Should You Do When Approaching A Low-Head Dam In A Canoe Or Kayak?

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Sam OBrien

What should you do when approaching a low-head dam in a canoe or kayak

That question right there will put the skills and knowledge of even the most experienced canoe or kayak paddlers to the test.

The shortest answer would be: 

Avoid them. 

However, the structures that earned the eerily title of “the killer in our river” aren’t as few and far between as you think. 

There are many dangers a kayaker must be aware of, but this is number one. You must understand the life-threatening risks low-head dams pose – and know what to do when you encounter one. 

Let’s get to it!

What Is A Low-Head Dam?  

Water flowing over a low-head dam

Low-head dams, or run-of-river dams, are a man made structure best described as minimal-profile walls of concrete running across the entire width of the river, from one side to the other. 

What sets them apart from a standard dam is that they’re not raised above the water. Instead, the wall is fully submerged and leveled with the surface of the water – hence the name “low-head.” 

Rather than blocking the entire waterway, low-profile barriers close it partially, raising water levels on one portion of the river. Once the water reaches the wall, it free-flows and drops to the lower level. 

The dams are small but deemed the most dangerous type of barrier for paddlers, nonetheless. 

Drone Footage: Powerful Low Head Dam.

Drowning machines – that’s how the paddling community calls them. 

Cute nickname, huh?

You’re probably wondering: 

But if these things are so dangerous for recreational boaters, why are they still in use?” 

Well, they were never meant to be a life-threatening part of recreational or sporting activities. 

Many of the low-head dams built on the US waterways originated back in the 1800s and early 1900s. Back then, these structures made perfect sense and helped power mills and small industries. 

They outlasted their original purpose a long time ago. Now, the dams regulate the flow rate, along with improve water supplies and help increase water irrigation to near-by farm land.  

You can encounter low-head dams in the United States’ rivers and streams in rural and urban areas. What’s more, there’s no reliable database regarding the total number of low-head dams; all we have are rough estimates, ranging from 3000 to 5000 throughout the US. 

Why Are Low Head Dams Dangerous to Small Boats and Paddle Craft?

Kayaker caught in the boil of a low-head dam

Low head dams are dangerous to small boats and paddle craft for an unfortunate combination of reasons.

Most significantly, these structures create treacherously strong currents that small watercraft can struggle to maneuverer through. Small boats, such as kayaks and canoes, can get caught in the hydraulic “boil” at the base of the dam, making escape extremely difficult.

Tragically, many accidents occur because the dams are impossible to spot beforehand and often left unmarked. Debris accumulation exacerbates the risks. Even rescue and recovery is complex with the powerful reciprocating currents.

Ultimately, the dangers arise from five key factors:

  • They Can Be Impossible To Spot
  • Low-Head Dams Are Often Left Unmarked
  • You’re Fighting Strong Currents
  • There Are All Sorts Of Floating Debris
  • You Can Get Caught In The “Boil”
  • Low-Head Dams Are Hard To Escape & Rescue Is Difficult

They Can Be Impossible To Spot 

Full-sized dams with massive spillway gates look way more intimidating, but you know they’re there

They sit under the surface of the water and are at best difficult to spot. Low-head dams, however, can be nearly invisible, given the right condition. Regardless if you’re in a canoe or kayak, you likely won’t see a low-head dam until you’re already on top of one. 

Canoe seats have a slight advantage, as they provide higher elevation and a better view. Kayakers sit lower on the water, making the situation worse.

So, knowing what should you do when approaching a low-head dam needs to be an instinctive reaction as you may only have seconds to act.

Low-Head Dams Are Often Left Unmarked 

There’s no official inventory of low-head dams across the US, with all but a handful of states failing to keep track: 

A total of 27 states provide rough estimates, and only three – Pennsylvania, Illinois, and Virginia – have statutory authority regarding public safety at low-head dams. 

Identifying Hazards and Improving Public Safety at Low Head Dams - 2013

Most dams are generally unmarked, with no warning signs, as there’s no legal requirement for it. You often won’t find their locations on maps, either. 

You’re Fighting Strong Currents 

Many people underestimate the brutal currents at play around low-head dams or overestimate their physical ability to overcome them. 

The dam’s size isn’t the enemy here, though – the destructive power of the currents is. 

Low Head Dams: Hidden Dangers

The forces, caused by the water flow, can be so powerful that they suck everything – boats, people and other debris – over the dam and into the recirculating current below. There, you encounter high hydraulic forces and low buoyancy.  

A dangerous recipe for disaster, that could prove to be a fatal mistake by anyone who is unlucky enough to be trapped by its pressure. 

There Are All Sorts Of Floating Debris 

Debris often accompanies higher rainfall, with branches and other solid materials floating around in the water. 

So, on top of fighting the actual currents, you have to protect yourself from the debris, which increases your likelihood of getting trapped and can lead to severe injuries. 

You Can Get Caught In The “Boil” 

The “boil” – a strong and recirculating current that forms right below the dam – is the most destructive force you will encounter in a low-head dam. This washing-machine-like turbulence, created as the water flows over the dam’s face, sucks everything and everyone in its path. 

Within the boil you’re pounded by the relentless hydraulic forces that pull you from the surface, drag you underwater and pin you against the dam’s wall, no matter how hard you fight. 

Fatal Currents - Low Head Dam Presentation

Even at low speeds, the force generated by the incoming water can be dangerous. And if you get pulled into the recirculating current below, the situation becomes extremely perilous, as you’re now at the mercy of the hydraulic forces.

If that happens, regardless if you are wearing a life jacket or not, you’ll be in a dangerous situation that could prove fatal – and without assistance from shore, you’re at real peril of drowning.

Low-Head Dams Are Hard To Escape & Rescue Is Difficult 

Even if you find your way to the surface, the continuous water flow and recirculating currents draw you back underwater – and the nightmare starts all over again.

Wearing a PFD is always recommended, but the highly aerated, turbulent waters of a low-head dam generate enough water pressure to render life jackets ineffective. 

The terrifying part is that once you’re in there, you’re on your own. Low-head Dam rescue is near impossible – and many rescue teams end up becoming victims themselves. 

What Are The Warning Signs You Are Approaching a Low-Head Dam?

There’s no one-size-fits-all answer to this question, as the warning signs there may be a low head dam approaching will vary depending on the size and design of the dam.

However, some general warning signs, that there might be an upcoming dam, include;

  • The water is moving much more quickly than usual.
  • The water is unusually turbulent, choppy or muddy.
  • There is debris or foam in the water.
  • There is a sudden change in the sound of the river or stream.
  • The banks around it are severely eroded.
  • You can’t see the bottom of the river or stream.

What Should You Do When Approaching A Low-Head Dam In A Canoe Or Kayak? 

Avoid word written and circled on a dry erase board to illustrate a warning or danger sign of things to prevent as a precaution for safety and security

The best advice I can give you, in relation to approaching a low-head dam, can be summed up in two simple words: 

Avoid them. 

Avoid them at all costs. Avoid them like the plague. Avoid them as if your life depends on it – because it does. 

But due to all the reasons mentioned earlier, that’s often easier said than done. 

DNR: Stay Away From Low-Head Dams At Any Cost

So, what should you do when approaching a low-head dam? Is there anything you can do? 

1. Check Local Waterways & Plan Your Routine 

Man planning his trip using a large scale map

There’s always a possibility of encountering unmarked low-head dams. 

Don’t test your luck, though – doing your research and planning your route is still better than nothing. 

Here’s a list of precautionary measures and tips that can help put together a safe paddling route: 

  • DO take the time to plan your upcoming paddling journey. 
  • DO get familiar with the area and gather information about the waterways.
  • DO check detailed waterway maps and guides, pay special attention to the map’s legend for low-head dams or other danger zones.
  • DO talk with the locals or contact a nearby paddling club. Local paddlers know the river and area better than anyone and may provide vital information. 
  • DO avoid the waterway if it features a low-head dam, and adapt your route accordingly. If that’s not an option, then cross the area on foot. 
  • DO watch out for signs and potential indicators that there are low-head dams ahead. 
  • DON’T rely on the warning signs alone, as they might not be found in every spot along your route. 

2. If You Come Across a Low-head Dam: Always Keep Your Distance 

Water water canoe paddling away from an oncoming low-head dam

If you still come across a low-head dam, despite your research and planning, keep your distance

Pick up on the warning signs sooner rather than later so that you have time to react while the waters are still relatively calm. As long as you maintain a considerable distance from the low-head dam, you should be able to maneuver your way to the nearest bank. 

That’s the safest course of action for any boater.

The closer you get to approaching a low-head dam, the more difficult it becomes to steer your kayak or canoe – until the currents take over completely.

Before its too late, paddle back upstream away from the danger. Don’t attempt going over it under any circumstances and put your efforts toward maintaining substantial distance, instead! 

3. If You Need To Pass: Paddle To The Shore & Walk Your Kayak or Canoe Around The Dam

man carries from the water a grey kayak on his shoulder

But what if you’d like to continue down your route? The only safe way to pass a low-head dam is to portage around the drowning machine, thus avoiding the situation.

Paddle to the nearest shore and walk around the dam until you reach navigable waters again. Be sure to move further down from the dam’s base, though – you might need to carry your kayak up to 100 feet if you want to be extra careful and completely away from he high-risk area . 

As this style of dam creates a perfectly uniformed drop, the “boil” can affect a large area. As a result, the currents that flow downstream can be dangerous even at significant distances from a low-head dam, and you want to avoid it. Only return to the water if you’re confident that the danger has passed.

It’s a massive annoyance – no one wants to haul a kayak or canoe around on foot – but it’s better than the alternative. 

Bonus Tip

If you’re paddling in a group, alert others about the low-head dam ahead and see that everyone returns to shore safely. 


So, to recap, what should you do when approaching a low-head dam

Avoiding them would be ideal – but if you enjoy exploring new rivers and streams, the odds are against you. Encountering one is pretty much inevitable. 

What’s important is that you don’t underestimate its destructive power once you do. 

Low-head dams are at best are difficult to spot, so research and plan your trips and keep an eye out for warning signs. If you come across a low-head dam, remain calm, keep a safe distance and paddle to the riverbank immediately. Portage is the best way to go about it – get out and carry your kayak around the dam. 

No, scratch that. 

It’s the only way to go about it. Never – and I cannot stress this enough – paddle over a low-head dam!

Simple as that! So now you can’t say you don’t know what should you do.

Stay safe – Happy paddling people!

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Sam OBrien

Sam is the founder and editor of WaterSportsWhiz. With over 20 years of experience across various water sports, he provides trusted reviews and expert advice to help others pursue their passion for getting out on the water. When not working, you can find him kayaking, paddle boarding, or planning his next water-based adventure with family and friends.