Scalable, efficient and economically viable solar evaporation ponds are weather dependent, and location may have more to do with the evaporation rate than any other variable. Under the right conditions, with ample sun, wind and temperature, evaporation will occur naturally at a rate that is sustainable and effective. The most common, and perhaps the best, way to increase the efficacy of pond evaporation is actually quite simple and intuitive: Increase the surface area of the pond and make it as shallow as is feasible to contain the largest volume of liquid that is expected to be contained. Sounds elementary, right? The goal is to expose the water surface to the highest amount of solar radiation possible. Location is critical for high evaporation rates, and there is no substitute for consistently hot, dry weather and low annual rainfall. Arid climates that boast strong sun even during fall and winter seasons are ideal.
Today, approved evaporation ponds in most locales also require a pond liner with the proper containment specifications. PE geomembrane liner is preferable to natural clay, lighter and less subject to failure, easier to install and more-cost-effective even for large-scale installations, even when double layers are required. With a 30-plus-year record of use, they have demonstrated their ability to perform admirably. Today, a dark top layer is often specified to help speed the rate of evaporation, and it is most effective because it tends to focus the sun’s rays at lower depths, especially as the water level dissipates. Most of the artificial means that can be employed to boost evaporation are marginal, at best, and some, like artificial wind generators or paddles and deflectors, seem to produce minimal effect.
