Who will become the water supply group supervisor during a high-rise fire?

The water supply group supervisor during a high-rise fire is the third arriving engine engineer. This choice is correct because the engine companies are primarily responsible for establishing and maintaining water supply operations during fire incidents, especially in high-rise situations where water supply logistics can become complex.

The engine engineer possesses the skills and knowledge necessary to manage the water supply effectively, including connecting hoses to hydrants, pumping water, and coordinating with other units to ensure adequate supply to the fire scene. In a high-rise scenario, managing water supply is crucial, as the elevation requires additional considerations for pressure and flow.

The roles of the other options do not align as closely with the responsibilities of establishing water supply. Ambulance personnel typically focus on medical emergencies; the second arriving battalion chief usually oversees overall operations and may not be directly involved in logistical aspects like water supply; and while the ladder operator is important, their primary concern is typically related to aerial operations and support rather than managing water supply logistics.