EVALUATION OF THE EFFECTIVENESS OF PASSIVE TREATMENT SYSTEMS FOR ACID MINE DRAINAGE IN THE SLIPPERY ROCK CREEK WATERSHED, WESTERN PENNSYLVANIA

Acid Mine Drainage (AMD) from coal mining has impacted the Slippery Rock Creek Watershed in western Pennsylvania for the past two hundred years. In the late 1990s, a combined group of State agencies, local environmental groups, and universities installed a series of Passive Treatment Systems in the headwaters of Slippery Rock Creek to treat AMD discharges from abandoned coal mines and oil wells. There were multiple goals for these Passive Treatment Systems:

1. Geochemically remove dissolved metals in the AMD.
2. Reduce the acidity and increase the alkalinity of the AMD.
3. Accomplish this within the Passive Treatment Systems before the AMD reaches the receiving stream.

In addition, the system effluent would make the stream more tolerant of untreated AMD discharges that enter it.

Our project's goal was to explore both the overall historical trends and the current state of the water chemistry of the Slippery Rock Creek watershed since the installation of the passive treatment systems. Thirteen sampling points were established in the receiving streams in the late 1990s to monitor the impact of the construction of the Passive Treatment systems. They have been sampled almost thirty times over the past twenty-seven years. We sampled them most recently during the Fall of 2022 and plan to sample them during the spring of 2023. The project will also provide insight into the effectiveness and operational status of the Passive Treatment Systems within the watershed by sampling the sources and outfalls of AMD passive treatment sites. Additionally, the project uses sUAS (small unmanned aerial systems) to detect AMD seeps and complete aerial surveys of Passive Treatment Sites to determine the operational status of the systems.