Those who irrigate their farms are working with a resource that is becoming increasingly scarce and expensive. Water rights are limited, extraction volumes are more strictly regulated, and during dry periods, the reservoir level determines whether crops survive the summer. A significant portion of this water never reaches the fields—it evaporates unused from the open surface.
How much water does an open irrigation basin lose?
Evaporation from an open storage basin depends on four factors: air temperature, solar radiation, humidity, and, most importantly, wind. Crucially, it's not the basin's volume that matters, but its surface area—a shallow, wide basin loses significantly more water than a deep one, even with the same storage capacity. This is precisely why agricultural storage basins are particularly vulnerable: they are usually shallow, exposed to the elements, and therefore unprotected from the wind. To make matters worse, losses are greatest when water is most needed—during hot, dry weeks with high solar radiation. Anyone wishing to quantify their losses can find an initial estimate using Euro-Matic's evaporation calculator based on their own basin's dimensions.
Why evaporation costs twice as much in agriculture
The most obvious loss is the water itself. The second, often overlooked factor is the concentration of what remains. When pure water evaporates, salts, nutrients, and minerals remain in the reservoir and accumulate. If the salinity increases, the water can become unusable for sensitive crops or contribute to soil salinization in the long term. Then there's the energy expenditure: every cubic meter that needs to be pumped back in consumes electricity or diesel fuel. For farms with wells or long-distance pipelines, this adds up significantly over the course of a season. Therefore, reducing evaporation not only saves water but also stabilizes water quality and reduces pumping requirements.
How cover balls stop evaporation
Pool cover spheres are floating hollow plastic spheres that lie freely on the water's surface and automatically collapse into a closed layer. They form a honeycomb-like structure that covers approximately 91 percent of the water's surface. This layer has a dual effect: it shields the water from direct sunlight and interrupts the air exchange above the surface, which drives evaporation. In practice, this can reduce water loss by up to 90 percent. Unlike a rigid tarp, the layer of spheres automatically adjusts to any water level—rising and falling with the water level without any intervention. The shape of the pool is also irrelevant: irregular edges, fixtures, or embankments are simply enclosed.
Less algae, less odor, cleaner filters
Algae growth requires light. Covering the surface deprives it of the basis for photosynthesis, effectively inhibiting algae growth—entirely without chemicals. This offers a tangible operational advantage for irrigation systems: algae are the most common cause of clogged filters and drip lines. Less biomass reduces cleaning intervals and the risk of system failure. At the same time, covering the surface reduces unpleasant odors that arise in nutrient-rich water during warmer months.
A third effect concerns birds: The closed layer of spheres prevents the area from appearing as open water. Waterfowl are not attracted and consequently carry less droppings and germs into the basin—an aspect that is becoming increasingly important for irrigation water used in food crops.
What the coverage means during operation
A common concern is water extraction. This is unfounded: The spheres float freely and do not obstruct pumps or inlets. If the water level drops, the layer follows and reappears on the smaller surface area. If it rises, it redistributes itself. No readjustment is necessary.
In winter, an additional benefit comes into play: the cover lowers the freezing point of the water surface by up to 10 °C. For businesses at high altitudes or in regions with periods of frost, this means that pools and equipment can be used for longer.
Material and lifespan
For continuous outdoor use, the choice of material is crucial. Euro-Matic's Bird Balls™ are made of UV-stabilized HDPE—a plastic that is resistant to prolonged sunlight, temperature fluctuations, and the substances commonly found in irrigation water. Under normal conditions, their lifespan is 25 to 30 years, and Euro-Matic offers a ten-year warranty.
Since this is a one-time investment without moving parts, drive systems, or maintenance technology, the costs are spread over a long period. The economic viability depends primarily on how expensive the water saved is for the respective operation and how high the previous pumping and cleaning costs were.
For which pools is the cover suitable?
| Application | Primary benefit |
|---|---|
| Agricultural storage and irrigation basins | Evaporation protection, algae control |
| rainwater collection basin | Water quality, bird control |
| Manure and nutrient basins | Odor reduction, emission control |
| Fish farming and aquaculture tanks | Temperature stabilization, shading |
| Irrigation ponds in fruit and wine growing | Water availability during dry periods |
Frequently asked questions
Do the spheres affect the water quality?
No. The HDPE used is chemically resistant and does not release any substances into the water. On the contrary, the cover usually improves the water quality because less algae grows and less external contamination occurs.
How many balls are needed?
The quantity is determined by the water surface area, not the volume. Since the spheres self-align, the area in square meters is sufficient for a reliable calculation. Euro-Matic determines the appropriate number of pieces based on your pool dimensions.
Do the balls need to be removed for cleaning?
Not during normal operation. The layer remains permanently on the water. For pool maintenance, the spheres can be pushed together and then reused.
Does this also work in strong winds?
Yes. The spheres lie deep in the water and together form a stable layer. For very large areas, a border is recommended to ensure the covering remains evenly distributed.
The next step
Whether a cover is worthwhile for your operation depends on the surface area of your pool, your water costs, and the existing algae problem. Euro-Matic has been manufacturing cover spheres for decades for applications ranging from agriculture to heavy industry and will calculate the appropriate quantity based on your specific dimensions.
Learn more about irrigation systems in agriculture or request a free consultation.
