The Trail Road Waste Disposal site has been operated by the local municipal government since it was first opened in 1980. The refuse disposal footprint covers a total area of approximately 65 hectares and was originally developed in four stages. Stages 1 and 2 are unlined landfill cells, and Stages 3 and 4 are underlain by low-permeability liners and leachate collection systems. The Ministry of the Environment granted and approved vertical expansion of all four stages after the completion of a Class Environmental Assessment (EA). Although Stage 4 was the active landfilling area at the time, it was decided to complete the vertical expansion of Stages 1 and 2 in anticipation of potential future urban growth east of the landfill site. Providing a temporary cap on top of Stages 3 and 4 would significantly reduce leachate generation during the expansion of Stages 1 and 2.
Our firm, in association with Golder Associates, provided design services for the grading, stormwater drainage infrastructure, and the temporary cap itself. The site drainage system was originally sized for a final cap placement over Stages 3 and 4 that would incorporate a vegetated cover. Therefore, the site drainage network needed to be re-sized to accommodate the significant additional storm runoff generated by an exposed, low-permeability interim cap. In addition to preparing design drawings and specifications, we were involved with tendering and awarding the contract for the construction, and overseeing the installation of the exposed interim geomembrane cap system. Construction and installation of the interim cap was completed at a cost of approximately $5M.
The unique challenges of this project were presented by the liner supplier in a technical paper co-authored by our firm at International Geosynthetics Conferences held in Edmonton, Alberta and Salt Lake City, Utah.