GCL-4 consists of a layer of bentonite encapsulated between two geotextiles (a nonwoven and a woven polypropylene geotextiles), needle punched together and laminated on one side to a polyethylene membrane for maximum performances under a wide variety of field conditions. This integrated matrix of bentonite and needle punched fibers provides high shear strength and allows the GCL-4 to keep low permeability even in presence of adverse installation conditions. The GCL-4 has high internal shear strength characteristics for steep slope applications.