Four Mile Run Green Stormwater Infrastructure Project

Four Mile Run encompasses Schenley Park and several Pittsburgh neighborhoods including Greenfield, Hazelwood, Oakland, and Squirrel Hill. Nearly a century ago, the natural stream in this area was diverted underground through pipes that are now part of the combined sewer system. This system sends sewer and stormwater directly to the river during CSO events. 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 naturalized 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.

Additionally, Pittsburgh Water and Sewer Authority 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 the Junction Hollow Trail in Schenley Park. For this project, Sci-Tek provided the follow services:

Flow Monitoring

• Provided flow and rainfall monitoring coordination and management including manhole inspections and site evaluations, detailed GIS mapping, and flow meter installation, maintenance, and calibration activities.
• Prepared the Sewer Flow and Rainfall Monitoring Report to summarize the flow and rainfall monitoring activities. The basis of this report is a sixth-month monitoring program using seventeen flow meters and ten rain gauges within the M-29 Sewershed.

Site Explorations

• Provided geotechnical services for stream restoration and tunnel alignment alternatives that will connect the restored Four Mile Run to the Monongahela River. This includes drilling test borings and installing groundwater monitoring wells and supporting the Basis of Design Report with geotechnical and geological information.

Permitting

• Prepared Erosion & Sedimentation Control Plans for the modification of the embankment dam and stormwater conveyance channel from Panther Hollow Lake to the Monongahela River.