03/10/2026
Most Allegheny County residents likely are unaware of a narrow stream with rust-colored water that meanders beneath roadways and private property in Mon Valley communities, including Elizabeth Borough and Forward Township.
Ultimately making its way to the Monongahela River, Fallen Timber Run is one of many polluted streams in the county — accounting for a whopping 67% of streams, 915 miles in total — designated as “impaired.” That percentage is high when compared to the state’s overall 37%, according to a draft water quality report from the state Department of Environmental Protection.
Across centuries, these streams have largely become impaired — meaning their waters don’t meet state standards for drinking, fishing or swimming. The region’s history of mining is a substantial contributor, and improvements to prevent sewage from entering waterways are ongoing, but the process is costly and slow.
“We live in a place with so much history, as one of the main sites of the industrial revolution,” said Heather Manzo, executive director of the Allegheny County Conservation District. “There have been generations of resource extraction in Pennsylvania and Allegheny County, and each causes a different kind of pollution that impacts water quality.”
Read more: https://www.post-gazette.com/life/outdoors/2026/03/08/allegheny-county-streams-impaired/stories/202603040088
