Which of these operations involves establishing a water source from a hydrant?

Establishing a water source from a hydrant is most accurately described by the reverse lay operation. In this context, the reverse lay refers to a method of laying hose from the discharge of a pumper back to a water source, such as a hydrant, that is located behind the pumper and away from the incident scene. This approach allows for the rapid establishment of a water supply while advancing towards the emergency.

The process starts with setting up the apparatus at the incident scene, then running a section of hose back to the hydrant to connect to the water supply. This technique is efficient, particularly when responding to fires or other emergencies, as it ensures that there is a continuous water source available for firefighting efforts while the crew can quickly advance toward the incident.

In this scenario, the other operations listed do not specifically relate to the process of establishing a water source from a hydrant. Changeover operation typically refers to the transfer of water supply sources, load shedding involves managing water flow to prevent overloading a system, and pump operation pertains to the function and management of the pump itself, rather than the setup of water sourcing from hydrants.