Use of Geosynthetic Drainage Materials at Landfills in Florida

In the late 1990's, the Florida Department of Environmental Protection became concerned that the increased use of geonets in landfill liner systems was not accompanied by appropriate transmissivity testing of these geonets in the designs. Some design professionals were simply using published data on geonet performance rather than determining what was needed based upon site-specific conditions. In addition, since many of Florida's landfills were expanding vertically and leachate recirculation was becoming more common, innovative designs with geonets were being proposed and the potential for improper use of geonets was increasing. Consequently, in 2001 the Department added a rule requirement that geonets used in landfill liner systems be tested with Method ASTM D4716. The maximum design load case requires a minimum test period of 100 hours. This paper summarizes this rule requirement, the basis for it and the concerns the Department has about improper design using geonets and geocomposites.