Small low-head dams can appear harmless and appealing to some thrill-seekers looking to beat the heat while enjoying their summer. But these small dams can become monstrous death traps when the downstream water levels rise.
“Know your river and the location of these low-head or overflow dams,” said BYU professor Rollin Hotchkiss.
Hotchkiss, along with his team of student researchers from the BYU Department of Civil and Environmental Engineering, researched the mechanics of a phenomenon called “submerged hydraulic jump,” which creates a pool of circling water that ensnares the victim.
“Going over a small drop of a few feet at an overflow dam looks to be easy and not even very thrilling,” Hotchkiss said.
He explained that the real hazard can be found in the dangerous counter current that these dams produce.
“It is very visual,” Hotchkiss said. “Thanks to the state-of-the-art research facilities in the Fulton College of Engineering and Technology, we can reproduce and demonstrate quite dramatically at a smaller scale why these countercurrents are so dangerous.”
It is no surprise that the number of deaths caused by low-head dams is steadily increasing. The research group found that since 1950, low-head dams account for at least 450 deaths in the United States. This statistic was gathered as part of the efforts of former BYU graduate students Ed Kern and John Guymon.
Under Hotchkiss’ supervision, the team created the low-head dam database website. The purpose of this website is to keep track of the fatalities caused by low-head dams, as well as raise public awareness.
“The problem is very difficult to solve and presents a real design challenge to address,” Hotchkiss said. “Efforts to publicize this danger, coupled with proper research, can save many lives.”
Hotchkiss hopes that making changes to government regulations and increased awareness could reduce the dangers and help save lives.
“State legislatures should be lobbied to provide funding to counties and cities to determine if there are any dangerous low-head dams in their jurisdictions and remove or alter the dam to reduce the danger,” Hotchkiss said. “Owners of low-head dams should ask themselves whether or not they really need the dam.”
Guymon expressed concern over safety issues present during rescue efforts. “Safety rescue personnel could die while attempting to help the victims, or while recovering the bodies from the non-stop current,” he said. “Unfortunately, the only answer to this problem is to raise awareness and encourage people to avoid getting into these types of situations in the first place.”
Kern feels that awareness and personal responsibility are key to remaining safe on the water.
“Swimmers, rafters and kayakers have a responsibility to familiarize themselves with the consequences of being around these types of structures,” Kern said.
The research team hopes to raise awareness to the public with the information they have at krcproject.groups.et.byu.net.
“People are very grateful to see their work publicized,” Hotchkiss said, “as most messages have been from families who have lost someone close at one of these dams.”