Short answer: Whether you need evaporation management on your dam depends on your climate, dam size, and how critical that water supply is to your property. In hot, inland Australian regions, a farm dam can lose millions of litres per year to evaporation — making management strategies like covers or floating plants well worth the investment. If your dam is your primary water source during dry periods, the answer is almost certainly yes.
What is the most effective way to reduce evaporation from a farm dam?
From most to least effective: floating impermeable covers (90–95% reduction), floating solar panels (70–80%), shade balls (50–80%), windbreaks (10–30%), deeper dam design (most cost-effective for new construction).
Does water depth affect how much evaporates from a farm dam?
Depth changes the proportion of total storage lost. A 2-metre deep dam loses approximately 60% of its volume to evaporation annually. A 6-metre deep dam with the same surface area loses only 20%. This is why Agriculture Victoria recommends building fewer, deeper dams.