Which hydraulic is considered the deadliest for rescuers and victims?

The low head dam is considered the deadliest hydraulic feature for both rescuers and victims due to its design and the nature of its flow dynamics. Low head dams create a situation where water flows over the top and cascades down, creating a strong recirculating current at the base. This current can trap and hold individuals beneath the surface of the water, making it extremely difficult to escape.

Furthermore, the danger is compounded by the common misconception that low head dams are safe or manageable because they're relatively small compared to larger dams. In reality, the force of the water and the drowning potential can be misleading, and the hydraulic effect can easily lead to panic or disorientation in those caught in its grip. This combination of factors contributes to a high risk of fatalities for anyone, including rescuers, who enter the water near a low head dam.

The other hydralics, while dangerous, generally do not present the same level of consistent and persistent hazard as low head dams do, making them comparatively less lethal in situations of rescue.