The Watershed » Overview
Nine Mile Run is a small stream that flows through Pittsburgh's East End. If you've ever driven through Wilkinsburg, Edgewood, Swissvale, or the east side of Squirrel Hill, you've driven over it. Of course, you don't need to cross a bridge to drive over Nine Mile Run because it is almost entirely underground.
Currently, Nine Mile Run is unhealthy, typical for an urban stream. This is a result of how little the stream has been valued historically. At the turn of the 20th century streams were often used to transport trash and sewage from homes, and most of Nine Mile Run was piped into underground culverts.
One-third of the stream was left above ground in Frick Park, emerging near Braddock Avenue and flowing 2.2 miles to the Monongahela River. This unique urban asset is located in a 6.5 square mile watershed that includes the boroughs of Edgewood, Swissvale, Wilkinsburg and part of the city of Pittsburgh.
Approximately 27% of the Nine Mile Run Watershed is covered by impermeable surfaces, which allow runoff to flow directly into storm drains instead of being absorbed into the ground. That means that during wet weather, Nine Mile Run is quickly overloaded with water, causing stream bank erosion and degrading habitats.
Non-point source pollution (dirt, litter, road salt, pesticides, oil, etc....) from runoff is ending up in the stream, along with sewage overflow from inadequate storm and sanitary systems. Most of the City of Pittsburgh uses a combined system in which both sewage and stormwater flow through the same pipes, allowing overflow to spill into Nine Mile Run when there is as little as a tenth of an inch of rain.
Wilkinsburg, Edgewood and Swissvale have a two-pipe system called a sanitary sewer system; one pipe to carry sewage and one to carry stormwater. However, many watershed citizens have (often unbeknownst to them) their downspouts connected to the sewer drains instead of the stormwater drains. The smaller sewer pipes cannot handle the extra volume of water and overflow. Many of the sewer pipes are also in disrepair. These old lines are often made of terracotta and there are even some brick manholes that are not watertight. The pipes are also often located in wetlands or near streams (many are right on the banks of Nine Mile Run) which means that sewage gets into into Nine Mile Run. more...
The Nine Mile Run aquatic ecosystem restoration was completed by the Army Corps of Engineers in July 2006. It was the largest urban stream restoration in the United States at the time of its completion. The restoration work included stream channel reconfiguration, wetland reconstruction, native wildlife habitat enhancement, and native tree, shrub, and wildflower plantings. Please click here for a more detailed description, FAQs, and photographic documentation of the restoration work. more...