Experts call them 'drowning machines.' So why are they on the Poudre?
Washington teen's death highlights potential dangers of swimming, tubing over low-head dams.
When Max Lopez hopped on an inner tube and floated down the Poudre River last week, there wasn't anything other than the sound of rushing water to warn him of the potentially deadly structure ahead.
The Washington teen was on the river with his 16-year-old cousin when the two passed over a low-head dam, something many experts refer to as "drowning machines." The violent current knocked Lopez off his tube and forced him under water. Despite rescue efforts, the 18-year-old drowned.
His death marked the first drowning of the year on the Poudre River, but as the weather warms and more people head to the river, some experts warn that more people could be in danger.
In the past 10 years, more than 15 people have drowned on the river from various accidents.
Lopez's death was the first in years involving a low-head dam.
These dams dot rivers across the country, including in Fort Collins, where there is one low-head dam every 1.5 to 2 miles along much of the Poudre.
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In Colorado, there is no agency in charge of overseeing safety at these dams. Instead, the Division of Water Resources has a team charged with overseeing the risks associated with large dams at sites such as Horsetooth Reservoir that could pose a hazard if they failed, Colorado Division of Water Resources Dam Safety Chief Bill McCormick said.
"I think these are some of the most dangerous type of structures we have in the country because most people are unaware of the dangers," said Bruce Tschantz, a Knoxville, Tennessee, water resources engineer who has studied low-head dams extensively. "People tend to overestimate their ability to overcome the current and underestimate the dangers."
In much of the country, low-head dams have been in place for more than 100 years to serve now defunct mills. In Colorado, many of these dams are still active, diverting water into irrigation ditches for agricultural use. While the structures are old, the danger is relatively new.
"The problem of safety around them is more a recent phenomenon as people are using the rivers more," McCormick said.
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The dams slow water upstream and divert it away from the main channel. The water that flows over them creates a rapid on the downriver side that mimics the hydraulics of a washing machine. The water can force victims underwater and spin them around, making it nearly impossible to swim back up to the surface.
"These structures are often very deceiving," said Kenneth Smith, Indiana Department of Natural Resources assistant director. "They may be very safe and (you're) able to play on them one day, and you come back a week later .... and it's gone from a quiet, scenic playful little place to this drowning machine."
Smith has worked to raise awareness about the dangers these dams pose and is a member of the Association of State Dam Safety Officials.
Simple engineering solutions can make low-head dams built today much safer by breaking up the flow of water as it moves over the dam. Solutions could include a set of concrete stairs or large rocks on the downstream side of the structure. In many cases, those solutions could be added to existing dams, but that can be costly, and it can be difficult to track down the owners of these century-old structures.
Poudre Fire Authority has been in discussions about what might be done to make sure people know about the dangers of the dams, including the possibility of installing signs along the river warning people of where they are.
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This effort has been complicated by several factors, including that many sites along the river are privately owned and property owners would need to give their approval before signs are installed.
Smith, who has been pushing similar safety efforts in Indiana, said he thinks the solution could be more complicated than that.
"Just because you put signs up, I'm not sure it's going to change a whole lot," he said. "Just because you put a sign up doesn't mean people will see them. It has to be far enough upstream that people have the ability to get out safety."
He said in Indiana some groups have installed signs ahead of these dams with an illustration of what can happen to swimmers if they pass over them, but he also thinks public education is the most effective way to prevent these deaths, especially with teenagers and people in their early 20s, who are the most common victims of these types of accidents.
He is also working with volunteers who are developing a location-based smartphone app that would track the user's location along the river and warn them when they get too close to a low-head dam.
Although most states have agencies that focus on dam safety, those efforts are largely concentrated around the physical upkeep of these structures and not how to protect people who might be swimming, rafting, kayaking or tubing around them.
"It's never something that's been made a legislative priority, to charge any one agency (with swimmer safety around dams), and it's something that really crosses multiple professions from first responders to engineering firms and anyone with the recreation industry, Smith said."