Mabel Davis Park Groundwater Investigation
Pollutant transport from municipal solid waste landfills is most often caused by water movement through waste to natural groundwater and is measured directly in landfill leachate collection systems and downgradient wells, seeps, and springs. These data indicate the source of groundwater and may dictate alternate management for pollutant attenuation. Following remediation, the Mabel Davis landfill was monitored through comparison of leachate volume, rainfall, and well water levels. In addition, water chemistry analyses were conducted including isotopic ratios related to source waters. Data collected from these investigations indicates the St. Elmo Terrace Deposit is the source of natural groundwater on the site. It also appears that this natural shallow groundwater is the source for Mabel Davis seep and the observed fluctuation in leachate volume. As a result, leachate volumes will continue to fluctuate with seasonal rainfall amount with large amount of leachate being generated during wet periods and low leachate amounts during drought conditions. Solid Waste Services may want to consider alternatives for management of remediated landfill cover to redirect infiltrating rainfall and ultimately reduce production of leachate to within design parameters.