Which technique should be used to manage a spinal injury in water?

Using a backboard to stabilize and retrieve a victim with a suspected spinal injury in the water is the safest and most effective technique. This method minimizes movement of the spine, which is crucial because any unnecessary motion can exacerbate potential injuries. The backboard provides the necessary support to keep the victim in a neutral position, reducing the risk of further harm during the rescue process.

In this situation, it's vital to keep the victim as still as possible to prevent worsened injuries. The other techniques involve actions that could increase the danger for the victim by risking further spinal injury. Encouraging a victim to swim themselves to safety could lead to additional movement and stress on their spine. Assisting them by turning them over poses a serious risk, as it could further aggravate any existing spinal issues. Leaving the victim until help arrives is not a viable option because immediate care and stabilization are necessary to minimize the risk of permanent damage. Thus, the use of a backboard is the preferred method for managing spinal injuries in water scenarios.