A geomembrane is a very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid (or gas) migration in a human-made project, structure, or system. Geomembranes are made from relatively thin continuous polymeric sheets, but they can also be made from the impregnation of geotextiles with asphalt, elastomer, or polymer sprays, or as multilayered bitumen geocomposites. Common uses include liners for waste containment (such as landfill liners), mining, and water containment applications. They are crucial in environmental applications to prevent contamination between the groundwater and the contained material.