Riverview Park Mairdale Avenue Stream Inflow Project

Riverview Park Mairdale Avenue Green Infrastructure Project

Riverview Park, located in Pittsburgh's northern neighborhoods, provides a serene respite within an urban environment. It offers 84 acres of open space that residents use for recreation activities throughout the year. However, when it rains there is a significant amount of erosion occurring as stormwater runoff travels through the urban forest and it eventually enters the sewer system. The stormwater and clean stream flow in Riverview Park takes up valuable space within the sewer system, and when it rains it mixes with sewage and makes its way to the outfall at the Ohio River contributing to the health and well-being of this important natural amenity. 

The Mairdale Avenue Green Infratructure Project will improve the park by using a combination of surface and subsurface green stormwater infrastructure to stabilize the stream banks to mitigate erosion, redirect and store the stream flow and capture stormwater runoff. The project will benefit the community and our water and sewer systems by:

  • Reducing the volume of combined sewer overflows during rain events
  • Decreasing instances of surface and basement flooding near the project area
  • Reducing sediment and debris loading and potentially blocking the combined sewer systems 
  • Improving water quality through the reduction of water flowing to the ALCOSAN Treatment Plant
  • Creating public amenities within Riverview Park that the community can enjoy

The Pittsburgh Water and Sewer Authority (PWSA), partner agencies, and Civil and Environmental Consultants (CEC) are developing design alternatives for Riverview Park. Conceptual design alternatives were presented at a community meeting on Thursday, April 5th.  Feedback from the community will be incorporated into the final design, which is expected to be complete in the summer of 2018. It is anticipated that construction will begin in 2019. The Woods Run Mairdale Avenue Green Infrastrucure project is part of PWSA's 2018 Capital Improvement Program. It is a ratepayer funded project and will recieve partial funding from ALCOSAN's Green Revitalization of Our Waterways (GROW) grant program. 

Project Outreach

November 12, 2017 - 1st Community Meeting / Site Walk 

April 5, 2018 - 2nd Community Meeting - Presentation of conceptual design alternatives. A brief summary of the design alternatives can be found hereNotes from the meeting are now available.

June 4, 2018 - 3rd Community Meeting - Presentation of selected design alternatives. Attendees will have an opportunity to comment and provide input for additional changes to the design.

If you would like to be notified regarding the next community meeting, please fill out the interest form linked here!  

Project Partners and Stakeholders 

  • City of Pittsburgh Department of Public Works
  • Allegheny County Sanitary Authority
  • Pittsburgh Parks Conservancy
  • Friends of Riverview Park



Woods Run Watershed Background

The Woods Run O-27 watershed is located in the North Western corner of the City, encompassing part of the City's Brighton Heights, Perry North, Perry South, and Marshall-Shadeland neighborhoods. The 3RWW's 2nd NatureReport notes that the Woods Run Watershed area is 1,280 acres, making it the 14th largest watershed in Allegheny County. The entirety of the watershed is considered a combined sewer system, meaning the stormwater and sewage are mixed in the same sewer system. As part of the PWSA City-Wide Green First Plan, the Woods Run Watershed was identified as one of the City's priority watersheds for the implementation of green infrastructure projects. 

One of the outcomes of the PWSA City-Wide Green First Plan  was the identification of eight stream inflow locations within the Woods Run Watershed. The eight stream inflow locations are a localized source of excess stormwater flows into our combined sewers, which ultimately result in reduced sewer capacity and sewer overflows during rain events. Based on localized opportunities, and its proximity to Riverview Park, PWSA prioritized the Mairdale Avenue stream inflow location as the first major inflow reduction project within the watershed. 



Mairdale Avenue Stream Inflow Location

The Mairdale Avenue stream inflow location is one of eight separate locations that sends surface stormwater and groundwater from adjacent hillsides and nearby impervious surfaces into the combined sewer system. Of the eight Woods Run stream inflow points, PWSA prioritized the Mairdale Avenue inflow location as an implementation project. 

The stream inflow and project location is located in the wooded area near the intersection of Mairdale Avenue and Riverview Drive ( the western entrance of Riverview Park). The stream drainage area consists of a 90-acre sub-watershed within the larger 1280-acre Woods Run Watershed. The stream traverses the sewer system for several miles before it eventually enters and ends up at the Allegheny County Sanitary Authority (ALCOSAN) sewage treatment plant. The stream begins in the woods within Riverview Park where it travels several hundred feet before it eventually makes its way to the intersection of Mairdale Avenue and Riverview Drive. At the intersection, the stream enters a 48-inch culvert where it then enters the combined sewer system that runs beneath the road along Mairdale Avenue. The Mairdale Avenue Project will focus on detaining the flows entering the sewer system, reduce erosion and sedimentation and manage peak flows from large storm events.