Floating Covers
Industrial modular cover systems for ponds, reservoirs, tanks, and lagoons.
Stop evaporation, eliminate algae, contain odors, and add thermal insulation — without draining the basin or pouring concrete. AWTT manufactures the only floating cover range to win a U.S. Department of Energy Sustainability Award.
What Is a Floating Cover?
A floating cover is an engineered surface barrier that rests on the liquid surface of an open pond, reservoir, tank, or lagoon. Modern industrial floating covers are modular — composed of interlocking HDPE elements (spheres, hexagonal tiles, or hybrid panels) that can be deployed by hand without civil work, structural modifications, or pond drainage.
Floating covers solve four operating problems that open liquid storage cannot avoid: evaporative loss, algae and cyanobacteria growth, odor and VOC emissions, and (for heated processes) thermal energy waste. They also deter birds and wildlife — a critical safety concern at airport stormwater retention and a contamination concern at potable reservoirs.
Unlike solid geomembrane covers, modular floating covers preserve the ability to lift sections for inspection, sampling, or partial drainage. They also accommodate basin shape changes (filling, drawdown) without buckling or tearing. For most industrial sites, modular is the correct choice; solid geomembrane is reserved for permanent installations where access is never required.
The Three Floating Cover Families
AWTT manufactures across all three modular floating cover families. Each is engineered for different priorities — coverage, wind resistance, insulation, or buoyancy.
Ball Covers
Armor Ball® · Armor Ball® AQUA
Hollow HDPE spheres giving ~91% surface coverage. The lowest cost per square foot of any floating cover family. Best for low-wind sites where evaporation reduction is the priority and partial coverage is acceptable.
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Hexagonal Tile Covers
Hexprotect® SLIM · AQUA · MAX R
Interlocking hex tiles achieving 99% surface coverage. Available in wind-resistant (130+ MPH) and insulated (R-17+) variants. The best all-around choice for drinking water reservoirs, biogas digesters, and high-spec industrial ponds.
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Hybrid Rhombo Panels
Rhombo Hexoshield® 66 · 189
Heavy-duty modular panels with the highest buoyancy in the industry — 25 to 50 lb/ft². 2017 U.S. DOE Sustainability Award winner. Engineered for the most demanding containment environments, with structural capacity for equipment access and accumulated solids.
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What Floating Covers Deliver
Six capabilities every AWTT floating cover delivers, regardless of family.
Up to 98% Evaporation Reduction
A 99% surface coverage stops bulk evaporative loss. For a 5-acre reservoir in arid climates, that translates to 20-50 million gallons retained per year.
Algae & Cyanobacteria Suppression
Blocking sunlight at the surface eliminates photosynthesis — algae blooms and harmful cyanobacteria collapse within weeks. Chemical treatment costs typically drop 70-90%.
Odor & VOC Containment
Sealed surface coverage traps H₂S, ammonia, and other emissions at the liquid surface. Critical for wastewater lagoons, biogas digesters, and industrial process water near populated areas.
Bird & Wildlife Deterrence
Eliminates open-water landing surface — preventing bird strikes near airport stormwater and contamination at potable reservoirs.
Thermal Insulation (R-17+)
Insulated variants like Hexprotect® MAX R deliver R-17+ on biogas digesters, cutting heating costs up to 85% and stabilizing methane production through cold months.
Extreme Temperature Performance
UV-stabilized HDPE rated from –70°F to +150°F. Proven across Alaskan municipal reservoirs and Texas oilfield evaporation ponds without seasonal failure.
The Full AWTT Floating Cover Range
Seven engineered systems. Use the product selector to match the right one to your site, or compare the headline specs below.
Armor Ball®
Hollow HDPE spheres giving 91% surface coverage at the lowest cost per square foot. Best for low-wind sites where ultimate evaporation reduction is the priority.
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Wind-Resistant BallArmor Ball® AQUA
Water-ballasted Armor Ball variant rated to 75 MPH wind — same 91% coverage with active wind resistance via internal water ballast.
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Most Affordable 99%Hexprotect® SLIM
Lightweight interlocking hexagonal tiles delivering 99% surface coverage at the most affordable price point. Best for tanks and sheltered ponds.
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Best All-AroundHexprotect® AQUA
The flagship 99%-coverage hexagonal cover — 130+ MPH wind resistance, NSF/ANSI potable water compliance, deployed across drinking reservoirs, industrial process water, and stormwater retention.
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R-17+ InsulatedHexprotect® MAX R
R-17+ insulated hexagonal cover with closed-cell polyurethane foam core. Reduces biogas digester and heated-lagoon operating costs up to 85%.
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DOE Award WinnerRhombo Hexoshield® 66
2017 U.S. Department of Energy Sustainability Award winner. 25 lb/ft² buoyancy, R-4 insulation, 130 MPH wind resistance. Saved 55 million gallons/year at the Savannah River Site.
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Max BuoyancyRhombo Hexoshield® 189
The highest-buoyancy floating cover in the AWTT range — 50 lb/ft² engineered for the most demanding containment applications. R-8 insulation, structural capacity for equipment access and snow loads.
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Where Floating Covers Are Used
AWTT floating covers are deployed across nine industries with distinct operating priorities. Industry pages show the recommended cover for each application along with case-relevant specifications.
Airports
Bird strike elimination, stormwater retention
Biogas Plants
R-17+ insulation, methane retention
Dairies
Lagoon odor & ammonia containment
Frac Ponds
95%+ evaporation reduction, wind resistance
Mining
Heap-leach evaporation, dust suppression
Reservoirs
Drinking water, algae prevention
Wastewater
Odor capture, lagoon coverage
Cement Plants
Process water evaporation control
Chemical Plants
VOC containment, chemical compatibility
How to Specify the Right Floating Cover
Five inputs determine which AWTT cover is the engineering match for a given site:
- 1 Surface area & geometry. Pond shape and acreage drive total module count and edge treatment. AWTT covers fit any geometry without custom fabrication.
- 2 Wind exposure. Sheltered sites can use any cover; exposed sites (mining pits, airport perimeter, open prairie) require wind-resistant variants (Armor Ball® AQUA, Hexprotect® AQUA, Rhombo).
- 3 Thermal requirement. Biogas digesters and heated lagoons need R-17+ insulation (Hexprotect® MAX R). Ambient-temperature ponds do not.
- 4 Load capacity. Sites requiring foot traffic, equipment access, or accumulated solids need high-buoyancy panels (Rhombo Hexoshield® 66 or 189).
- 5 Regulatory context. Potable water reservoirs require NSF/ANSI 61 compliance (Hexprotect® AQUA). Chemical compatibility for solvent/oilfield exposure requires AWTT engineering review.
Why AWTT
2017 U.S. DOE Sustainability Award
The Rhombo Hexoshield® 66 won the U.S. Department of Energy's 2017 Sustainability Award after saving 55 million gallons per year at the Savannah River Site. No other modular floating cover manufacturer has received this recognition.
North American Manufacturing
Every AWTT cover is manufactured from UV-stabilized virgin HDPE in North America. Material is fully traceable, NSF/ANSI 61 certified where applicable, and free of recycled or post-consumer content. Global manufacturing partners support delivery to South America, Europe, Africa, and Asia-Pacific.
10-Year Warranty · 25+ Year Lifespan
All AWTT floating covers carry a 10-year manufacturer warranty against material defects and a documented 25+ year operational lifespan. Some installations have exceeded 30 years of continuous service.
700+ Installations
AWTT covers are in service at airports, military bases, drinking water utilities, oil & gas operators, mining sites, dairy lagoons, and biogas digesters across all 50 U.S. states and 25+ countries.
Floating Cover FAQ
What is a floating cover? +
A floating cover is an engineered surface barrier — typically modular HDPE elements or geomembrane sheet — that rests on the liquid surface of a pond, reservoir, lagoon, or open tank. It reduces evaporation, blocks sunlight (which suppresses algae), traps odors and VOCs, deters birds and wildlife, and can add thermal insulation for heated processes.
What are the main types of floating covers? +
There are three main families of modular floating covers: (1) ball covers — hollow HDPE spheres giving ~91% coverage at the lowest cost; (2) hexagonal tile covers — interlocking hex elements achieving 99% coverage with optional wind resistance and insulation; (3) hybrid/rhombo panels — heavy-duty modular panels with the highest buoyancy (50 lb/ft²) for severe operating environments. Solid geomembrane covers are also available but are not modular and require permanent installation.
How much evaporation does a floating cover prevent? +
Ball covers reduce evaporation by approximately 85-91% depending on layout. Hexagonal modular covers reach 95-98% reduction at 99% surface coverage. Solid geomembrane covers reach 99%+ but lack maintenance access and structural flexibility. For most industrial sites, modular 99%-coverage systems deliver the best payback because they preserve the option to lift sections for inspection, sampling, or partial drainage.
Do floating covers work in high wind? +
Yes — wind-resistant variants are rated from 75 MPH (Armor Ball® AQUA) to 130+ MPH (Hexprotect® AQUA, Rhombo Hexoshield® 66 with water ballast). Wind rating depends on cover geometry, ballast strategy, and perimeter restraint. For airports, mining pits, and open-pit reservoirs in exposed terrain, AWTT recommends Hexprotect® AQUA or Rhombo as the baseline.
How long do floating covers last? +
AWTT modular HDPE floating covers have a 25+ year operational lifespan under typical industrial conditions, backed by a 10-year manufacturer warranty. UV-stabilized HDPE resists chemical attack, freeze/thaw cycling (–70°F to +150°F), and biological fouling. There are AWTT installations exceeding 30 years of continuous service.
Can floating covers be installed without draining the pond? +
Yes. Every AWTT modular floating cover is installed on the existing liquid surface — no drainage, no civil work, no heavy equipment. Modules are launched and interlocked by hand or with a small boat. A typical 2-acre reservoir installs in 3-5 days with a 4-person crew.
Ready to specify a floating cover?
Send your pond dimensions, location, and use case. AWTT engineering returns a sized recommendation, lead time, and quote within 1–2 business days.