TRACKING THE IMPACTS OF A FAILING PASSIVE WETLAND TREATMENT SYSTEM, MORAINE STATE PARK, PENNSYLVANIA

Following extensive underground coal mining during the previous century in western Pennsylvania, many abandoned mine entries were closed and sealed to protect surface waters. Even though these seals were intended to prevent mine water from impacting the surface, many of them failed and countless seeps and leaking entries have damaged streams and lakes throughout the region. In Moraine State Park, Lake Arthur is a man-made lake situated over largely undermined areas, many of which are expected to negatively impact the surface water systems. One location, in the eastern side of the park, had multiple leaking mine seals that were directly entering the lake. This site was remediated in 1996 with a passive wetland treatment system to protect the lake and preserve the quality of the water for the fishing and recreation in the area. After many years of successful buffering of the mine effluent, the treatment system showed signs of failure, with overgrowth of vegetation in the ponds and iron precipitate entering Lake Arthur. Since 2008, students at California University of Pennsylvania have been monitoring various aspects of the treatment system to determine its performance and its prognosis for the future. Measurements have included precipitate thickness, residence time, surface water chemistry, lake sediments, and ground water chemistry. All indications are that the Lake Arthur passive wetland treatment system has failed and is no longer protecting the lake from the abandoned mine drainage. Not only is there direct effluent discharging from the ponds, but flooding of the ponds and leaking through their beds has influenced the soil and ground water around them. There is potential for rejuvenating the pond system through dredging and redevelopment, to reverse the current problems.