This project involves installation of five (5) gas monitoring wells at Central Landfill that consist of minimum 8-inch diameter boreholes in native volcanic soil and rock, completed to depths of 25 to 60 feet below existing grade. Each borehole has from one to three monitoring intervals with ¾-inch diameter PVC pipes in sand backfill, separated by bentonite plugs. Each well is completed with a locking cap and traffic bollards.