Sprinkler Drift & Evaporation & What Never Lands

Wind drift and evaporation loss (WDEL) is the share of sprinkler water that never reaches the soil — fine droplets blow away on the wind or evaporate in mid-air before landing. It is highest in hot, dry, windy weather and from tall risers that throw water high, and it directly lowers how much of your applied water the crop actually receives.

The loss rises with wind speed, air temperature and the height the water is thrown, and falls with humidity. This tool combines those drivers into an estimated loss percentage, then computes the effective depth — the part that lands on the soil — from the depth you applied. It is a planning estimate, not a lab measurement.

Wind shears the spray into fine droplets and carries them off-target, so even a moderate breeze can sharply increase loss and unevenness. Loss climbs steeply above roughly 3–4 m/s, which is why irrigating in calm conditions — early morning or evening — saves the most water.

Higher risers throw water further up and out, giving droplets more time aloft to evaporate and more exposure to wind. Lowering the riser, or using low-pressure or low-angle nozzles, keeps droplets larger and closer to the ground, cutting both drift and evaporation.

The effective depth is the water that actually reaches the soil: applied depth minus the drift and evaporation loss. If you apply 10 mm and lose 18%, only about 8.2 mm reaches the crop. Scheduling on the applied depth without allowing for loss leaves the crop short, so the effective depth is what you should match to the crop need.

Irrigate in calm, cool parts of the day; use larger droplets via lower pressure or appropriate nozzles; lower the riser or use drop tubes; and avoid running in strong wind. Switching to low-energy precision application or drip removes most drift and evaporation loss entirely.

Yes — dry air evaporates droplets far faster than humid air, so the same wind and temperature cause much higher loss on a low-humidity day. Hot, dry, windy afternoons are the worst combination; cool, humid, still mornings are the best for application efficiency.

In calm, humid conditions loss may be only a few percent, but in hot, dry, windy weather with high risers it can exceed 20–30% of the applied water. That is why this loss is a major reason field application efficiency for sprinklers is often quoted around 75%.

It is a sound planning figure based on the main drivers, but real loss also depends on nozzle type, pressure, droplet size and local conditions. Verify with catch cans in the field if you need precise numbers, and adjust your scheduling to match what actually lands.