Four Mile Run encompasses Schenley Park and several Pittsburgh neighborhoods including Greenfield, Hazelwood, Oakland, and Squirrel Hill. These neighborhoods, like many throughout Pittsburgh, experience the impacts of stormwater that has nowhere to go. When it rains hard, as it often does, stormwater overflows into streams and rivers, floods neighborhoods, and causes sewage to overflow into streets and basements – all of which create severe threats to public health and safety.
Nearly a century ago, the natural stream in this area was diverted underground through pipes that are now part of our combined sewer system. This system sends sewer and stormwater directly to the river. Over time, much of the land within Four Mile Run was paved over. While these were standard practices of the time, they are no longer acceptable and contribute to the recent problems of flooding and sewer overflows throughout Pittsburgh. The Four Mile Run stormwater improvement project will capture and route the flow of stormwater through a new surface channel that will generally follow the path of the historic streams that formed Four Mile Run from Panther Hollow Lake to the Monongahela River. Panther Hollow Lake will be allowed to discharge to the Monongahela River instead of the combined sewer.
Redirecting the flow of water through a naturalized surface channel will help to prevent combined sewer overflows and reduce the intensity of flooding that occurs throughout Four Mile Run. Additionally, PWSA is evaluating the construction of wetlands and other natural stormwater treatment systems along with improvements to Panther Hollow Lake. These improvements will help to control sediment, provide habitat for wildlife, and filter pollutants from the stormwater before it enters the river.
This project provides opportunities to construct additional nature-based stormwater solutions that will improve water quality by reducing the amount of stormwater entering the combined sewer system. It also includes the restoration of recreation uses at Panther Hollow Lake and improvements to Junction Hollow Trail in Schenley Park.