Utilities · Application

Reservoir covers

Reservoir evaporative loss is equivalent to 20% of the global annual consumption of water.

On the water

Floating WaterPearls mats form a complete evaporation cover over the reservoir.

Up to 77–98% less open-water basin evaporation

77–98%

Evaporation reduced

50 yr

Lifespan

20%

Of global water use lost to evaporation

Field documentation

Measured in the field: 91% lost, 2% retained.

A side-by-side pan-evaporation trial near Johannesburg, South Africa (28 Nov – 23 Dec 2015 · 25 days · one 8 mm rain event). An uncovered control pan lost 91% of its water to evaporation; a pan under four layers of WaterPearls lost just 2%.

91%

Evaporated from the uncovered control pan

Evaporated under 4 layers of WaterPearls

~98%

Evaporation suppressed at 55 mm bead depth

Cumulative-evaporation and suppression-vs-bead-depth measurements, RHST field trial, Johannesburg S.A., 2015. Suppression scales with layer depth — from ~40% at 14 mm to ~98% at 55 mm.

How it works

A complete floating cover.

Mesh mats

Thousands of WaterPearls are inserted in 45 cm × 100 cm mesh mats, in options of 2 to 4 layers.

Installed on the reservoir

WaterPearls mats are installed on the reservoir, forming a complete cover.

Repel water

Just like a lotus leaf, the WaterPearls repel water.

Performance

Stop the loss at the surface.

Reduce water evaporation by 77% to 98% depending on the number of layers of WaterPearls in the mats
Prevent algae formation
Help limit bromate formation by reducing light and algae growth
Insulates the water body
White-coloured to raise surface albedo and reflect incoming solar radiation

Cumulative daily evaporation: the uncovered control pan loses ~13 cm of water over 25 days while pans under WaterPearls layers stay near flat — Cumulative evaporation — control vs. WaterPearls layers

Evaporation suppression rising from ~40% at 14 mm bead depth to ~98% at 55 mm — Suppression vs. bead-layer depth

How it compares

Built to outlast the alternatives.

Most evaporation covers trade one problem for another — short life, chemical residue, or limited coverage. WaterPearls are engineered to avoid all three.

Shade balls

Plastic, and a 10-year replacement cycle.

HDPE spheres carry a high production water footprint and are typically replaced about every decade. WaterPearls last up to 50 years with a far lower production footprint.

Chemical films

Slow evaporation by roughly a third — for days.

Mono-layer surfactant films are wind-sensitive and degrade within days, needing constant re-dosing. A WaterPearls cover stays in place and is permeable to rain and air.

Biological covers

Modest savings, real water-quality risk.

Floating plants cut evaporation only modestly and can deplete oxygen in the water. WaterPearls suppress 77–98% of evaporation while limiting algae and bromate formation.

Benefits

Engineered to float and last.

50 years lifespan
Mats are permeable to water — rain flows through
Mats are permeable to air — avoid oxygen depletion in reservoir
Floats and stays in place in the reservoir
Non porous to prevent absorption of water in the WaterPearls and harbouring of bacteria
Very low production water footprint in comparison with shade balls