Geomembranes are used in order to contain liquids and gases, whether to control their flow, transport the substance, or contain it over a long period of time. These liners first grew in availability and popularity in the 80's, where their properties were shown to particularly ideal for controlling leachate within waste management and landfills.
You can use a geomembrane to line your pond, cover your greenhouse, protect a patch of earth, or defend bales of hay from sunlight and moisture.