When installing a mineral drainage layer over a geosynthetic seal, a needlepunched
nonwoven geotextile can replace the otherwise necessary sand protective layer atop a geomembrane. In these situations, one should also evaluate whether a filter/separation geotextile would be an optimal solution between the drainage layer and cover soil.
In landfill closure projects, it is increasingly important to utilise steeper slopes to minimize the soildisturbing footprint of the site. The multilayer nature of sealing systems, however, complicates this spacesaving goal. It represents a particular challenge to the shear strength between layers. Here, textured geomembranes provide enhanced frictional characteristics for slope stability. Additionally, geogrids can be used to enable costeffective, safe engineering of steeper slopes.