The author performed a preliminary analysis of a circulation apparatus that reduces evaporation and enhances water quality of surface water reservoirs. Water waves within a reservoir will provide the renewable energy for natural circulation of water from the epilimnion to the hypolimnion through a circulation apparatus. The warm surface water in the epilimnion will be collected and conveyed through a concentric tube to lower water temperatures in the hypolimnion by the wave energy. As a result, the surface water temperature of a reservoir will be reduced by allowing warmer water at the surface to be conveyed to the colder water temperatures. In addition, the warm water and cold water will be mixed together allowing the overall water temperature in a reservoir to potentially equalize. The hydraulic circulation will ultimately lower the surface water temperature of a reservoir, reduce evaporation, and enhance water quality by partial for full destratification of a reservoir. There is a significant reduction in firm yields of major reservoirs due to evaporation losses and potentially by water losses due to climate change. The circulation apparatus will provide an alternative for effective management of reservoir storage capacity to meet future water demands and hydrologic conditions. Includes 7 references, figures.