Danger: Low-head dam safety on the Sequatchie River
Low-head dams don’t look particularly menacing. Thousands of these low-level structures were built on American rivers and streams in the 1800s and early 1900s to power gristmills and small industries. With a short drop of up to 5 feet, low-head dams can seem like a minor inconvenience-or even a thrill-for paddlers and swimmers. However, the churning waters at the base of these dams present a high level of danger to the unwary.
Since 1960, at least 350 documented fatalities have occurred at low-head dams in the United States, according to Dr. Bruce Tschantz, professor emeritus at the University of Tennessee. Two-thirds of these fatalities occurred in the past 15 years, and most occurred on weekends between April and August.
DANGERS OF LOW-HEAD DAMS
Often referred to as ”drowning machines,” low-head dams produce dangerous recirculating currents, large hydraulic forces, low buoyancy and other hazardous conditions sufficient to trap and drown victims. Upon entering the churning water at the base of the dam, the victim is pounded by a never-ending wave of water that forces them to the bottom. If they can bob up to the surface, the recirculating current carries them back to the dam and the nightmare begins again.
“Most people underestimate and are ignorant of the forces and currents that surround these low-head dams, and they overestimate their abilities to overcome these forces,” said Tschantz, who maintains the website www.SafeDam.com to help inform the public about dam safety and the dangers of low-head dams. “Even Olympic swimmers wouldn’t be able to overcome these forces & currents”
LOW-HEAD DAM NUMBERS UNKNOWN IN THE SOUTHEAST U.S.
There are no reliable inventories of how many exist in the U.S. today, but a study by the Association of State Dam Safety Officials estimates there may be as many as 5,000 low-head dams across the country.
In the Sequatchie Valley, there is a dangerous low-head dam on the Sequatchie River at Ketner’s Mill in the Whitwell and Powells Crossroads area.
In July 2015, three men drowned on the Sequatchie River at Ketner’s Mill. Two brothers were swimming in the river when one was swept over the low-head dam. The other brother and another man jumped into the water to save him, but police said all three drowned. A near-drowning occurred there the day before, as well.
There are also two other small dams on the Sequatchie River in the Pikeville area.
Public safety experts urge all swimmers, anglers, boaters, paddlers and tubers to check river maps and ask locals for locations of dangerous structures before setting out on any unknown waterway. On unknown waters, watch for a smooth horizon line where the stream meets the sky, which can potentially indicate a low-head dam.
Avoid approaching low-head dams and all spillway structures from both upstream and downstream, especially during high-water conditions. To learn more, watch the low-head dam safety video produced by the Illinois Paddling Council and visit www.SafeDam.com.