This was most likely what is known as a low-head dam or “drowning machine”. They can be anywhere from 6 inches to 20 feet in height. They are designed to create a downward force at the interface of the water and dam, as well as a back flow. This essentially forces debris or a victim down, as they come up, the back flow forces them back towards the dam, where the cycle continues. The main purpose is to force debris such as tree limbs and logs down to the base of the dam where many have large projections to break-up the debris.

Due to numerous deaths of would be rescuers, many new, highly advanced techniques have been developed to allow boat teams to approach without entering the eddy/back flow area of these low-head dams. The techniques are still very risky and require extensive training to develop and maintain proficiency. Pete