GCL
Geosynthetic Clay Liner A geosynthetic clay liner (GCL) is a woven fabric-like material, primarily used for the lining of landfills. It is a kind of geomembrane and geosynthetic, which incorporates a bentonite or other clay, which has a very low hydraulic conductivity. The resulting lower permeability slows the rate of seepage out of the landfill.