Low Head Dam Safety
A low head dam is a manmade structure spanning a river or stream channel from bank to bank in which water flows over the entire length of the top of the dam. Moderate to high flows over such dams create strong turbulent and recirculating currents at the base that push victims under water, and then pull them back to the face of the dam in a repeating cycle.
These dams typically range from a one to 15-foot drop. Because of their relatively small size and drop, low head dams may not always appear to be dangerous.
The more than 150 low head dams cataloged in Indiana are dangerous for swimming, boating, fishing and other water recreation. When recreating in a natural body of water, be aware of the distance from any low head dams.
Before visiting areas for water recreation, plan to avoid low head dams. The Indiana Department of Natural Resources offers planning resources on canoeing trails throughout Indiana. More information is available at http://www.in.gov/dnr/outdoor/4461.htm
WFYI Indianapolis, has created a documentary on the dangers of low head dams. The documentary was filmed in partnership with IDHS, IDNR, the Indiana Silver Jackets, Indiana University Purdue University Indianapolis, Manchester University and the U.S. Geological Survey, among others.
Watch the documentary online at http://www.wfyi.org/programs/over-under-gone/television/over-under-gone-the-killer-in-our-rivers
Below are two photos of the same low head dam in different conditions. The top photo is when the water level is relatively low. Note how difficult it would be to see the low head dam from upstream. The second photo shows the same dam at a much higher water level. It’s almost impossible to see at any angle. The current in both situations – low water and high water – can be deadly.