What exactly are geomembranes, and why are they useful? Polymeric geosynthetic barriers (colloquially “geomembranes”) are, by definition: factory-assembled structures of low-permeability synthetic materials in the form of a sheet, which acts as a barrier to control or mitigate fluid or gas migration into the environment. They are often used in landfills, ponds, coal refuse containment, and other applications to provide a barrier between the soil and possible contaminants (1, 2). Geomembranes are...