Glossary
Floating Cover
A physical barrier that floats on a water surface to block sunlight and air contact, reducing evaporation. Types include modular tiles or balls, continuous geomembrane sheets, and suspended or floating-solar systems.
Reported evaporation reductions vary by type and coverage: modular covers are often around 65–80% in field studies (e.g. Mady et al. 2021; Lehmann et al. 2019 wind-tunnel), rising toward 95–98% at near-full continuous coverage. Continuous geomembrane covers can seal 95%+ (Yao 2021; Craig 2005) but involve buoyancy, anchoring, rain-drainage, and gas trade-offs. Manufacturer figures, attributed to AWTT, include up to 95% for Hexprotect® AQUA and up to 98% for Rhombo Hexoshield®.