Flows through Gated Structures

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In addition to dangerous flows entering conduits, head-gate structures near entrances to locks, spillways and intake structures create hazards as water flows under or through the gate openings. An undercurrent, undertow, or sudden and unexpected release of water can occur when the gates are raised, especially if done under remote or automatic control. This hydraulic hazard is most commonly found at locks, gated spillways, and intake structures. We never fail to underestimate the power and persistence of flowing and standing water.

On June 19 of 2016 at the Melvin Price Lock and Dam in Alton, Illinois, a man was knocked off his jet ski near the upstream face of the dam on the Mississippi River when he hit a floating log. Even though he was wearing a life jacket, the man and his jet ski were subsequently sucked down through the gate opening about 17 feet below the water surface before resurfacing on the opposite side of the dam. He was rescued nearly one half of a mile downstream. Although he was physically exhausted from the ordeal, he was fortunate and suffered only minor injuries as a result of the incident. Many others are not as fortunate. Stay clear of locks and gates on waterways.

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Revision ID: 3517
Revision Date: 09/16/2022