The percentage of a water body's surface area physically covered by a floating cover. The dominant driver of evaporation and algae suppression effectiveness.
The coverage ratio is the percentage of a water body’s surface area physically covered by a floating cover at full deployment. It is the dominant driver of evaporation and algae suppression effectiveness: AWTT publishes 99% effective surface coverage for the Hexprotect® AQUA hexagonal element, spherical (armor ball) covers achieve ~70–80%, and continuous geomembranes achieve ~100%. Coverage ratio scales approximately linearly with evaporation reduction in field conditions.
The 99% effective coverage figure is published by AWTT for the patented self-ballasting hexagonal element geometry — see the manufacturer reference or /heritage for the engineering provenance.