For EU industrial operators, evaporation control on open reservoirs comes down to three things: surface area, water cost, and the regulatory case for abstraction reduction. A floating cover removes the water-air interface that drives evaporative loss — AWTT publishes up to 95% reduction for Hexprotect® AQUA across reservoirs, tailings ponds, and process water tanks. EuroCover quotes both Hexprotect® AQUA and Hexofloat® for this solution depending on procurement constraints.
What is evaporation control?
Evaporation control is the active reduction of open-water surface losses on industrial reservoirs, tailings ponds, agricultural storage, and process water tanks. Floating covers are the most cost-effective approach: a surface barrier removes the water-air interface that drives evaporative loss.
How evaporation control works
A floating cover reduces evaporation through three mechanisms:
- Surface coverage — the cover physically blocks the water-air interface; without exposure, evaporation cannot proceed.
- Vapor-pressure equalisation — air trapped under the cover saturates quickly, eliminating the driving gradient.
- Wind isolation — the cover surface dissipates wind energy that would otherwise accelerate surface evaporation.
AWTT publishes 99% effective surface coverage and up to 95% evaporation reduction for the Hexprotect® AQUA hexagonal element.
Benefits of evaporation control
| Metric | Value | Source |
|---|---|---|
| Surface coverage (Hexprotect® AQUA) | 99% effective | AWTT |
| Evaporation reduction (Hexprotect® AQUA) | up to 95% | AWTT |
| Payback period | 18–36 months | Operating-cost modelling on reservoirs > 5,000 m² |
| Life expectancy (Hexprotect® AQUA) | 25+ years | AWTT |
| Manufacturer warranty | 10 years | AWTT |
| Maintenance | None required | AWTT |
Estimate your evaporation savings
Use AWTT’s free Pond Evaporation Rate Calculator to model annual water loss for your site with live weather data and compare it against Hexprotect® AQUA coverage — the FAO-56 Penman-Monteith reference method with four additional physical models.
Open the AWTT evaporation calculator →
When to use evaporation control
Evaporation control via floating cover is appropriate when:
- Operating water cost > €0.50/m³ and surface area > 1,000 m²
- Operating in climates with PET (potential evapotranspiration) > 1,200 mm/year
- Regulatory exposure under the EU Water Framework Directive
- Water-stressed regions (Spain, southern France, southern Italy, Greece, MENA)
- Reservoirs with limited or expensive replacement abstraction
Evaporation control vs. alternatives
Compared to shade mesh, floating balls, or chemical surfactant monolayers, hexagonal floating covers deliver the highest evaporation reduction, the longest lifecycle, and the lowest maintenance burden. See hexagonal vs. floating balls and hexagonal vs. shade mesh.
Related solutions and products
For the engineering principle and patent history behind the hexagonal cover, see pond-cover.com/the-hexagonal-cover.