Abigail Gilson Beth Wilbanks Clay Liners containment geosynthetics education Electrical Leak Location ELL engineering engineering geology EUROENGEO FedIGS GCLs GeoAmericas 2020 geoemembranes geogrids geopipe geosynthetic barriers geosynthetic durability geotechnical engineering IAEG IGS IGS Brasil IGS Brazil IGS Chapter IGS North America IGS-NA International Geosynthetics Society Iran Jie Han Kent von Maubeuge MARV Michael Pluimer PDH Prague reinforcement geosynthetics Richard Thiel rock mechanics TC-B TC-H TC-Hydraulics TC-S TC-Stabilization Technical Committee on Hydraulics Technical Committee on Stabilization Technical Webinar webinar workshop