Embodiments generally relate to methods and apparatuses for conserving water in a reservoir. In one embodiment, the method comprises deploying onto the top surface of water in a reservoir a floatable device with a wettable lower surface. The device comprises a first element and a second element, the first element providing the device with a high albedo upper surface. In one embodiment the first element comprises a plurality of highly reflective particles and the second element comprises a binder configured to hold the reflective particles together.
