Geomembranes with a high rate of UV resistance can be exposed directly to sunlight, others will need to protected from sunlight underneath at least 6 inches of soil. Treated and woven geomembranes, like RPE's, can often handle direct exposure to UV rays. Others, like PVC, will need a soil-cover to protect them from degradation.
In order to properly anchor a geomembrane, the use of an anchor trench or shelf combined with a ballast is the most common solution. The depth of the ballast is determined by the weight of your geomembrane, and the conditions of the water above. Most backyard pond liners can be anchored with a trench only 6 inches deep.
