April 9, 2021
As warm weather brings opportunities for water recreation such as swimming, fishing, and kayaking in Utah’s rivers, we urge you to be particularly cautious around low-head dams.
A low-head dam is a horizontal structure spanning a river to back up water for irrigation, power, or navigation. Water accelerates over the top of the dam and plunges into the downstream channel, forming a turbulent, recirculating current. Even on small rivers these “submerged hydraulic jumps” or “hydraulic rollers” are deadly to river-goers who unknowingly get trapped in them. Between 2018 and 2020, there were 111 reported deaths in the United States associated with low-head dams.
Most incidents at low-head dams occur with the recreation season from April to September. Accordingly, the American Society of Civil Engineers (ASCE) has designated April as “Low Head Dam Public Safety Awareness Month.” As summer approaches, we urge you to be particularly cautious when recreating on and around rivers.
If you’d like to learn more or help improve safety around low-head dams, consider doing the following:
- View the ASCE website on low-head dams
- Explore an online inventory of low-head dams
- Learn how to identify low-head dams in Google Earth
Photo at top: Andy Waddington / Low head dam at Newby Bridge / CC BY-SA 2.0
Graphic above: Iowa Department of Natural Resources