How Fish Are Making a Comeback in Montour Run
Acid Mine Drainage and Fish Health

With fishing season upon us, here’s what your Conservation District is doing to improve your experience.


The Fish of Montour Run
Montour Run is home to smallmouth bass, sheepshead, carp, and catfish. These fish are a critical part of the watershed’s ecosystem as well as the local economy. Montour Run also intersects with the Ohio River, a popular fishing destination.

Read more about what's next for Montour Run.

Pollution in Milk Run
Milk Run, named for its polluted color, contributed some of the most acid mine drainage (AMD) to the watershed system – eventually flowing into the Ohio River. Through deforestation, AMD, flooding, river bank erosion, sediment buildup and stormwater runoff (especially from commercial and residential development); Montour Run became highly polluted – decreasing the fish population most at the junction where the Ohio River and Montour Run meet.

These types of conditions create hypoxic waters and dead zones where fish cannot survive. This interrupts migration patterns, reproduction and the overall health of the population. All these factors were a recipe for poor fishing in Montour Run.

Read more about acid mine drainage in Montour Run

Acid Mine Drainage Cleanup
The 16-inch clay drain pipe (see diagram below) from an underground coal seam is the largest abandoned acid mine drainage discharge source in the Montour Run watershed. It is formed from the weathering of a mineral called pyrite, or fool’s gold, over time creating sulphuric acid. This lowers the pH in groundwater and dissolves aluminum in the layer of clay that runs underneath the entire system. When this dissolved aluminum mixes with less acidic water from a connecting tributary, it creates the milky color of Milk Run.


The Montour Run Watershed Association and other organizations have been working to improve the water quality for over 20 years. The Milk Run treatment system went online on July 11, 2019, after a year of construction with the help of many community partners, and teams are already documenting fish returning to the stream.


Fish are abundant again in Montour Run, thanks to the Milk Run AMD cleanup.

Happy Fishing, Allegheny County!

After four years of collecting, organizing and analyzing data, ACCD has completed the Montour Run Watershed Assessment and Implementation Plan. This plan outlines data previously collected over the years by a number of watershed stakeholders, pollutants affecting the stream and ways to improve water quality. ACCD and Ethos Collaborative used a combination of field visual assessments and GIS modeling to get a complete look at the watershed.

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