The recent dam collapse in Brazil which left over 300 people dead and around 150 people missing was a catastrophic failure of a local mining company. Now Dam Safety is an important topic. People are asking how being safe around dams. Our nation’s dams provide not only power and drinking water, but also flood control along with many other benefits. But they can also pose a significant threat for those who live downstream should they ever fail.
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Dams in the United States
There are an estimated 84,000 dams in the United States. Now you can understand why dam safety has been a major goal since the U.S. Army Corps of Engineers (USACE) began building them in the 1840s. It is important that you know if you or your property may be affected by the presence of a dam and what measures to take if you are.
Many times, people make the mistake of focusing on larger dams when it comes to safety concerns. Reality though is the most dangerous dams aren’t those massive concrete structures often imagined when picturing a dam. It’s another kind of dam…
Most of the emergency situations are caused by low-head dams, better known as run-of-the-river dams. Low-head dams are characterized by their rather low height as compared to traditional large and deep dams. Low-head dams usually have a drop off between 1 to 15 feet. This allows the water to flow over the dam during a flood.
Dangers of a Low-Head Dam
Did you know when the water flows over the top of the dam, it creates strong, circulating currents below the surface of the water? It’s called a “hydraulic roller”. Often, people and objects such as boats get trapped underwater against the face of the dam.
The main concern here is that the extremely strong currents make it an inescapable trap. The sturdiest lifejacket clad person and even boats cannot escape from the effects.
Don’t Be Fooled
One of the reasons why low-head dams are dangerous is the water around them usually appears to be misleadingly calm and tranquil. Drowning victims often make the mistake of jumping in the water from a boat without knowing the risks. Others are caught unaware of the low-head dams that are difficult to spot from upstream.
It comes as no surprise that many of the victims of drowning around dams happen to first responders and would-be rescuers. They lose their life trying to save another’s by getting caught in this deadly and unseen hydraulic current under the surface of the water.
Sadly, many of the incidents which occur around dams are between the months of April and August. This is when families and friends head to low-head dams to take advantage of the high waters upstream. Others use the rich habitat around dams to fish.
Safety Precautions Around Dams
It is not only important to be aware of the scope of the dangers of low-head dams and dams in general, but also on ways in which you can keep yourself and family members safe to avoid tragedy. Contrary to popular belief, there are many things that can go wrong around a dam. Therefore, it is so important for people to remember to keep their distance both upstream and downstream. If you do have to go out on a waterway then it is important to remember the following:
Get Familiar with the Area of a Dam
Before heading out to the waterway try these two tips to find out the most common hazards on the waterway of a low-head dam:
- Speak with the locals
- Check out maps of the area
Some dams and spillways do not have visible piers or crests above the water level. Upstream boaters have a difficult time identifying the dam. This condition is known as an “infinity pool.”
Infinity Pool Characteristics
This occurs when the edge of the crest blends into the downstream area when viewed from upstream, not making the drop visible until it’s too late. If you are swimming or fishing on the waterway be sure to remain a safe distance away from the structure. If kayaking or canoeing is your thing, then remember to portage around the structure or turn around before you reach the dame to avoid being pulled over by the current.
Pay Attention to the DAM Signs
US Flood Control and FEMA (Federal Emergency Management Agency), have put signs around dam structures for a reason. It is crucial to read and obey all signage that has been placed around the dam. You should also avoid crossing any barriers that have been placed in the area. Oftentimes, dams and spillways are not marked by signage. This is where talking to locals and using maps to learn more about the care can keep you safe from potential dangers.
Wear a Personal Flotation Device
When it comes to dam safety a good dam safety rule of thumb is
Do not get into the water near a dam or anywhere for that matter without a personal floatation device or a lifejacket.
Whether you are boating, fishing or swimming around a waterway, wearing a lifejacket can save your life. Wearing a life jacket can be especially useful if you are caught in a hydraulic roller, where the water churns and aerates. A hydraulic roller creates air bubbles that can decrease the buoyancy of water by a third. In this area, swimmers struggle to stay afloat without a lifejacket.
Also, never moor, tie or anchor a boat below a dam since it won’t take long for the area to get inundated.
Don’t Be a DAM Hero
This is going to be hard to hear for some folks, but if you see someone in trouble, do not jump in the waterway.
Especially if you are a mediocre swimmer.
Dial 911, or use a remote assistive device, such as rope, stick or a throw bag to try and pull them to safety. It’s better to use a remote assistive device than ending up being the second person the rescue team must get out the water.
Dam Safety Ending Note
Dam safety was not recognized until 1889. The incident was the failure of South Fork Dam in Pennsylvania. It took the lives of over 2,200 residents. Always be aware of the many dangers that being or living around dams can lead to. It’s important for you to learn about the risks of dams and the various ways in which you can stay safe when faced with an emergency situation on a waterway.