An example of a surface water supply would be:

A reservoir is indeed an example of a surface water supply. Reservoirs are artificial lakes created by damming rivers or streams, designed to store water for various uses such as drinking, irrigation, or recreational activities. They are an integral part of surface water management and play a critical role in maintaining water supply, especially in areas where natural water sources may be insufficient to meet demand.

The importance of identifying reservoirs as surface water supplies lies in their ability to collect and hold large quantities of water directly from surface runoff, contributing to the water cycle and local ecosystems. This distinction is crucial for environmental health professionals as it underlines the various sources of potable water and the management practices necessary to maintain their quality and availability.

Other options listed, such as wells and springs, pertain specifically to groundwater sources rather than surface water supplies. Understanding the difference between surface water and groundwater is essential in effective water resource management and environmental health practices.