Geosynthetics APRIL/MAY 2023 Volume 41 Number 2 16 ON THE COVER An aerial view of a geomembrane being pulled across the water surface on the right side of the highway. Features 16 Motorway underpass using geomembranes as a groundwater barrier By Dick van Regteren 22 Contamination from a leaking geomembrane-A necessary and imminent evil? By John Tippett, PE, and Michael Goard, P.Eng. 28 Geosynthetic clay liners: An effective and efficient solution By Michael Kozak, J.D. 28 22 GeosyntheticsMagazine.com 3