Cooper, Brian, Northeast Coldwater Habitat Program, Trout Unlimited, 18 East Main Street, #3, Lock Haven, PA 17745, brian.cooper@tu.org; Rummel, Shawn, Northeast Coldwater Habitat Program, Trout Unlimited, 18 East Main Street, #3, Lock Haven, PA 17745, shawn.rummel@tu.org; Lutz, Allison, Northeast Coldwater Habitat Program Trout Unlimited 18 East Main Street, #3 Lock Haven PA 17745, allison.lutz@tu.org; Wolfe, Amy, Northeast Coldwater Habitat Program, Trout Unlimited, 18 East Main Street, #3, Lock Haven, PA 17745, amy.wolfe@tu.org.
Abandoned mine drainage is among the leading sources of stream impairment in Pennsylvania and the top source of impairment in Pennsylvania’s coldwater streams. AMD is created when pyritic rock is exposed to air and water during mining operations, forming sulfuric acid and dissolving naturally occurring metals such as iron, aluminum, and manganese. Trout Unlimited, along with many partners, has been active in AMD remediation in Pennsylvania for over 25 years. Successful treatment of AMD results in significant reductions in acidity, dissolved metals, and sulfate, and the return of healthy biological communities.
Results of multi-year monitoring of the effects of treatment on water quality and biological communities demonstrate positive impacts at multiple scales. At the discharge scale, we see effective elimination of acidity and dissolve metals content. At the stream-reach scale, we have documented water quality improvements that restored naturally reproducing trout populations and benthic macroinvertebrate communities below passive systems constructed and maintained by TU and our partners. At the large watershed scale, the cumulative effect of many AMD treatment systems (most of which are located in first and second order watersheds) led to the dramatic reduction of acidity and metals in the West Branch Susquehanna, along with increased diversity and abundance of fish. At the Chesapeake Bay scale, reductions in acidity and metals may be harder to appreciate due to dilution, but AMD treatment still provides benefit through improved overall water quality and an under-appreciated side benefit: sediment reduction.
Although not accounted for in the Chesapeake Assessment Scenario Tool (CAST), AMD treatment systems remove sediment from the Chesapeake Bay watershed by forcing the precipitation of dissolved metals into solid waste within the treatment system where they can be removed for disposal. These dissolved metals would otherwise precipitate as sediment downstream. Therefore, the observed reduction of metal concentrations in the West Branch Susquehanna has positive implications for the role of AMD treatment systems in achieving sediment reduction goals for the Chesapeake Bay. Further study is needed to quantify the total sediment reduction service being provided by Pennsylvania’s many AMD treatment systems, and AMD treatment warrants greater consideration in efforts to restore the Chesapeake Bay.
