In landfills HDPE geomembranes (thickness higher or equal 2.0 mm) are used nearly exclusively. In groundwater protection, mainly 1.0 mm thick HDPE geomembranes are used. In tunneling applications, mostly geomembranes with a signal layer are installed. Steeper slopes can be accommodated by installing a geomembrane with structured surfaces. Needle-punched geosynthetic clay liners with mechanically bonded nonwovens (300 g/m2
) as cover and carrier geotextiles are especially suitable for steeper slopes because they normally achieve higher interface friction angles than other geotextiles.