Pittsburgh Water and Sewer Authority (PWSA) completed an assessment evaluating the benefits of incorporating Green Infrastructure (GI) throughout the city to address regulatory requirements, as well as provide social, economic and environmental benefits. The City-Wide Green First Plan, released in December 2016, will guide where GI will be installed based on the effectiveness of capturing high volumes of stormwater runoff and feasibility of implementation. The findings of this evaluation will be used to reduce Combine Sewer Overflow (CSO) volumes within the PWSA service area. The findings will also guide and inform future capital improvement projects and urban planning decisions throughout the City.
In 2015, PWSA started a Green Infrastructure Grant Program to support GI projects that decrease the amount of CSOs in the city, stimulate economic development, and revitalize neighborhoods. PWSA received 38 applications from property owners and community organizations through its first GI grant program. PWSA and members of its GI Technical Advisory Committee have announced the awardees of the program. For more information visit our website.
In 2014, PWSA converted a highly visible and under-utilized traffic island in front of the water treatment plant in Aspinwall into a rain garden. This installation collects runoff from the surrounding impervious driveway and parking area through both curb cuts and a trench drain. StormWorks designed and provided construction management with in-kind excavation and planting assistance from PWSA staff. This project is a training opportunity for PWSA employees to learn more about green infrastructure and how to properly maintain them. (Photo by Katherine Camp)
The Saw Mill Run Watershed includes 14 Pittsburgh southern hilltop neighborhoods in addition to 11 other municipalities. This watershed experiences extensive flooding and stormwater issues but is not included in ALCOSAN's Phase 1 tunnel expansion plans. Recognizing this as an opportunity, in 2014, PWSA partnered with Economic Development South, a multi-municipal community development corporation active in the same geography, to bring all the Saw Mill Run municipalities together to develop a holistic, cost-effective plan to meet water quality standards. Using the EPA's Integrated Watershed Management Approach, we are analyzing the watershed's pollution sources and will select high impact projects that improve water quality across the watershed instead of focusing narrowly on individual pollutants within each municipal boundary. Get more information on the Saw Mill Run IWM Plan here.
In 2015, PWSA collaborated with Nine Mile Run on the Rosedale Runoff Reduction Project (RRRP) to manage stormwater with a goal of removing 25 million gallons from the combined sewer system. This goal will be achieved in two phases: Phase 1 is a project located at the intersection of Oakwood and Batavia. The design consists of a series of bioretention areas planted with native plants and trees that have additional underground storage to detain peak storm events. A flow-limiting orifice from the under drain of the system connects back into the combined sewer via a catch basin. This orifice will allow detained stormwater to be slowly released back into the combined sewer system after peak storm events, reducing combined sewer overflows. Phase 2 is a project at the Crescent Elementary School where street runoff and overland flow from the school property are redirected into a series of rain gardens with additional underground storage. Construction for these projects were completed summer of 2016, post construction monitoring will be on going to monitor the effectiveness of these projects. (Photo from rosedalerain.com)
In the summer of 2016, PWSA began installation of a GI demonstration project in the Banksville neighborhood of the City of Pittsburgh. This project involves 15 rain garden systems located within the public right-of-way strategically placed throughout the neighborhood. These systems use subsurface stone storage and modular storage systems to maximize the storage capacity of each individual system. This project is intended to minimize historic basement backups experienced during rainfall events and the dispersed locations of the systems create a green network in the neighborhood increasing aesthetics. Approximately 0.79 Million Gallons of water can be captured and removed from the combined sewer system in a year with this system.
In 2016, PWSA began design work on the Melwood Avenue GI Project located in the Polish Hill neighborhood of the City of Pittsburgh. This project involves the construction of bioretention features with underground storage as well as additional permeable paver installations within the public right-of-way. Based on survey work and design calculations, 1.78 acres of impervious surface runoff will be captured and managed through the roadside GI features. These street projects will alleviate 1.02 MG of combined sewer overflows annually, construction will begin in 2017.
In the spring of 2016, PWSA began designing the Hillcrest Project located on a vacant lot in the Garfield neighborhood. The vacant lot is located at a low elevation compared to its surroundings, presenting an opportunity to demonstrate the effectiveness of managing stormwater through the use of green infrastructure.
PWSA is proposing to implement three bioretention areas with underground storage, a walk way through the parcel, and flex pavement. This system will effectively handle runoff from 1.6 acres of impervious surfaces from the surrounding area. This system will be a visible asset to the community with landscaping and a walkway through the parcel while also managing the stormwater. Construction will begin in 2017.
In 2017, PWSA will implement the use of “smart” green technology to monitor Panther Hollow Lake. OptiNimbus is a continuous monitoring and adaptive control service that will help achieve regulatory compliance and ultimately address water quality and CSO impacts in the Panther Hollow Watershed. Recent flow monitoring data shows that the Panther Hollow Lake contributes an estimated 30 MG of wet weather flow per year. OptiNimbus will allow PWSA to interactively monitor and manage the water level in the lake. The system will also give PWSA the ability to lower the water level in the lake prior to anticipated precipitation events, enhancing peak discharge attenuation and reducing downstream CSO and flooding events. Initial estimates show a net reduction of approximately 1.5 MG of wet weather storage may be possible. (Photo by Megan Zeigler)
The Mairdale Avenue Stream Inflow is one of 8 separate locations within the Woods Run (O-27) watershed that routes surface draingage from hillsides and nearby roads into the combined sewer system. Of the 8 Woods Run stream inflow points, PWSA prioritized the Mairdale Avenue inflow location. Direct stream inflow takes up valuable conveyance capacity in the collection system and also uses a portion of the available treatment plant capacity. The stream base and wet weather flow currently discharges into the 48” diameter PWSA combined sewer on Mairdale Avenue. This project will aim to ecologically restore the stream while providing storage to retain and hold water and accumulated sediment during rain events. Get more information on the Woods Run Mairdale Avenue Project here.