The Etna Green Infrastructure Master Plan Project

This ongoing study was financed by a grant administered by the Pennsylvania Environmental Council (PEC). The objective of the study to assess the feasibility of reducing/eliminating proposed gray infrastructure alternatives by managing the 90% of Typical Year 2003 runoff through the implementation of green solutions within the Borough of Etna, a combined sewer system community. In addition, the project is intended to develop a methodology for communities evaluate and select basin retrofit options using Shaler Township as a case study.

The project uses innovative site screening techniques developed by Landbase Systems to conceptually locate and size green infrastructure (GI), referred to as Best Management Practices (BMPs).  The screening started not with availability of sites but identification and prioritization of high yield inlets via the Etna GIS where GI could be most advantageously sited.

The Etna Borough GIS model was used in tandem with available soils, slope, and other land use/cover data to characterize the individual catchment areas contributing to the Etna combined sewer system. Each of the catchments was associated with a combined sewer overflow.

The calibrated SWMM Etna sewer system model is used to evaluate the impacts of GI BMPs on the volume and rate of flow during the so-called Typical Year 2003. These impacts would be measured as changes in the frequency duration and volume of overflows.  As the SWMM model extends to the ALCOSAN point of connection, it was possible to estimate the impacts on the volume to be conveyed and treated by ALCOSAN after implementation of a program of GI BMPs in the Borough.

The Borough has already began construction on several of the projects identified in the Plan.  This is Phase I of the Green Streetscape Project, completed in August of this year.  This project will remove over 500,000 gallons of stormwater from the combined sewer system.

Green Streetscape Infrastructure Projects

Phase I

Etna Green Streetscape Phase 1:  Phase 1 of the project  is completed and was supported by PADEP Growing Greener and US EPA Section 319 Grants with a match by the Borough of Etna.
  • Acreage Managed: 0.598
  • Impervious Acreage Managed: 0.470
  • GSI Management Strategy: Filter/Infiltrate/Remove
  • Runoff Managed: 0.64 MG/yr (640,000 gal/yr)

Cost: $475,000 including engineering (Actual to date)

The first phase involved reconstruction of the east side of Butler Street between Bridge and Freeport Streets as well as the reconstruction of the north side of Freeport Street between Butler Street and Union Alley. This phase involved th installation of 12 street trees, 2300 cubic feet of underground storage that would promote infiltration, 3900 square feet of pervious pavers, downspout disconnection and restatement to new conveyances and related work. Storm water management is essential to water quality in our streams, creeks and rivers. It can also have a dramatic effect on drinking water quality as it reduces pollutants in ground water. As rain water travels over paved surfaces it picks up grit and debris including salt and other pollutants and deposits them into the combined system or into the ground. Collecting this rain water at is source helps to eliminate this from happening.

The project entailed other improvements and traffic calming/safety features: 562 feet of realigned curbing to create bump-outs, 4776 square feet of new concrete sidewalk, 403 feet of 12” wide  decorative ADA compliant grate and trench, tree grates, four new curb ramps and two new inlets to accommodate parking area drainage.

Phase II

Etna Green Streetscape Phase 2: Construction of Phase 2 (Etna Green Master Plan Phase 1 GSI Site 196) has been completed in 2017.
  • Acreage Managed:  0.65
  • Impervious Acreage Managed: 0.425
  • GSI Management Strategy: Filter/Infiltrate/Remove
  • Runoff Managed: 0.50 MG/yr  (500,000 gal/yr)
This second phase involves reconstruction of the south side of Butler Street between Winschel and Freeport Streets as well as the reconstruction of the south side of Freeport Street between Butler Street and Cherry Alley. This phase includes planting areas with 9 street trees, 2470 cubic feet of underground storage in two locations that infiltrate collected runoff, a reconstructed street section with 1800 square feet of pervious pavers, and a “Rain Park”. It also includes treatment of collected runoff using a proprietary bio-filtration system and a “green” inlet with a stormwater treatment insert.

The Freeport Street Rain Park is designed to manage runoff from the sidewalk and roofs along Freeport Street representing a total tributary area of approximately 9300 square feet. Of this total area approximately 7300 square feet is impervious surface. The rain park itself is approximately 1900 square feet in area with perennial plantings.  It uses a high rate proprietary infiltration media to treat and retain entrained solids in collected/conveyed runoff in advance of storage. The facility has 842 cubic feet of subsurface storage and is designed to infiltrate the runoff from a 1.25 inches rainfall event over a 72 hour period. The facility has an overflow pipe that directs excessive RO volume to a nearby catch basin on the corner of Cherry Alley and Freeport Street.

The Love Street Facility is designed to manage runoff from the sidewalk and roofs along Butler Street and Praeger Street conveyed by new piping systems as well as roof runoff from adjacent buildings and other contributing areas tributary to the street such as yards and gravel parking areas. The facility has a total tributary area of approximately 20,900 square feet. The Love Street facility is designed to infiltrate 1629 cubic feet of collected runoff stored in modular storm water storage units (MSSUs) installed under 1800 feet of pervious pavers. In order to install the facility it was necessary to re-route the existing sewer. The facility has an overflow pipe that directs excess RO volume to a new manhole on Praeger Street.

By its nature, the Green Streetscape creates a strong linkage between transportation considerations and the Etna urban context.  The Phase 2 of the project therefore includes other improvements and traffic calming/safety features: 554 feet of realigned curbing to create bump-outs, 6280 square feet of new concrete sidewalk, 660 feet of 12” wide decorative ADA compliant grate and trench, tree grates, six new curb ramps and a new inlet to accommodate parking area drainage.

The project removes runoff from roof, sidewalk and other impervious areas from the combined sewer system and routes it through new conveyances for subsurface storage and infiltration. Based on the completed project, the Phase 2 project will manage runoff from a 0.65 acre area of which 0.425 acres is impervious.  This translates into an estimated average of 0.5 MG of runoff managed annually.

Phase III

  • Acreage Managed: 0.829
  • Impervious Acreage Managed: 0.638
  • GSI Management Strategy: FIRm 
  • Runoff Managed: 1.08 MG/yr (1,081,204 gal/yr)

Cost: $701,100 including engineering

Streetscape Phase III captured contributory drainage areas are approximately 45,643 square feet (1.05 acres). The proposed improvements included the installation of 490 linear feet of 12” decorative trench drain within the exposed aggregate concrete sidewalks which conveys the sidewalk run-off and the roof run-off from some of the buildings along Butler Street and directs the run-off to one of the two proposed underground infiltration tanks located on Walnut Street and High Street. Also, seven tree pits with grates were also installed in series with the trench drains to allow for addition infiltration along the streetscape. In addition, new landscape bump-out areas were created and the existing impervious areas were removed and converted into planted landscaped bump-out areas. Lastly, three catch basins with FABCO water quality filters were installed along the intersections of Walnut Street/Butler Street and High Street/Butler Street that now direct the street run-off to the infiltration tanks and no longer discharge directly into the combined system.

Tank 1 on Walnut Street has the capacity to retain/infiltrate approximately 9,672 gallons. It also has the capacity to capture and manage approximately 293,924 gallons annually (removal from the combined system).

Tank 2 on High Street has the capacity to retain/infiltrate approximately 21,750 gallons. It also has the capacity to capture and manage approximately 787,280 gallons annually (removal from the combined system).

Therefore, both systems have the combined capacity to retain/infiltrate approximately 31,422 gallons and manage approximately 1.08 MG annually (removal from the combined system).

Etna Rain Garden

Rain Garden Design and Management Technical Workshop

The Borough of Etna, through its partnership with the Sustainable Lands Program, and a grant from the League of Women Voters, Water Resource Education Network, hosted a technical workshop for the design and management of a rain garden on September 7, 2013.  As part of that program, an actual hands- on approach was taken for the second half of the workshop and a beautiful, sustainable rain garden was installed at the Clarence Fugh Memorial Park and Swimming Pool Facility on Pine Street.  The Borough provided the monetary match and the site location for the rain garden.  The entire program was videotaped, courtesy of Shaler School District and will be posted on several educational and environmental websites.  Instructors included Sandy Feather, Penn State University Extension, Sara Madden, Stormworks, Barton Kirk, Seeds and Roxanne Swann, Audubon Society of Western Pennsylvania.

About 40 landscape contractors, landscape architects, students and interested parties attended the one day session held form 9 am to 3 pm in the Municipal Building.  The event organizers included Allegheny County, Allegheny County Conservation District, Audubon Society of Western Pa., the City of Pittsburgh, the Pa. Department of Conservation and Natural Resources, 3 Rivers Wet Weather, the Penn State Center, Nine Mile Run Watershed Association/Stormworks, Penn State Extension,  Seeds and the Borough of Etna.

The agenda included discussion on what a rain garden and bioswale is; how to site these facilities; how to size, design and cost these facilities and the necessary installation methods.  Experts spoke of the appropriate plants for these installations and how to address maintenance of rain gardens.  The afternoon session was an on-site rain garden installation at the Borough’s Swimming Pool Bathhouse.  Two rain gutters were disconnected from the combined sewer system and incorporated into the garden installation.  The rain garden is approximately 180 square feet and is receiving runoff from a roof area of 470 square feet and is designed for a 1 ½ inch rainfall (storm).  Removing storm water from our combined sewer system is something we are dedicated to in our community to help address localized flooding, cut down on sewer overflows to our creeks and rivers and to help reduce the cost of sewage treatment.  While this is one small project, it demonstrates the Borough’s commitment to Stormwater Management within our own community.  If you are interested in addressing stormwater at your own home or business property, contact the Borough Manager at 412-781-0569.  

Below are just some of the pictures of the workshop.  The site is beautiful and functions wonderfully – as was evidenced by the heavy downpours just a few days after installation.  Watch for the video of the entire program which will be posted on this website as well as other websites.The rain garden at the pool is registered on the Rain Garden Alliance website -  www.raingarden.org

The Etna Borough School Street Parking Lot Green Infrastructure Project

 
Completed in July, this project uses new technology, a unique stormwater best management practice (BMP) that consists of a 20-square-foot high-rate biofiltration system that directs the infiltrated water into a 1,060-cubic-foot stormwater management storage unit. The facility receives runoff from over an acre of contributing area and is projected to capture approximately 540,000 gallons of stormwater annually from the borough’s combined sewer system. This project was developed with funding assistance from the Richard King Mellon Foundation through 3 Rivers Wet Weather to show the value of adding green stormwater features as part of the reconstruction of the parking lot at a more affordable cost.


Freeport Street Rain Park

The Freeport Street Rain Park is designed to manage runoff from the sidewalk and roofs along Freeport Street representing a total tributary area of approximately 9300 square feet. Of this total area approximately 7300 square feet is impervious surface. The rain park itself is approximately 1900 square feet in area with perennial plantings. It uses a high rate proprietary infiltration media to treat and retain entrained solids in collected/conveyed runoff in advance of storage. The facility has 842 cubic feet of subsurface storage and is designed to infiltrate the runoff from a 1.25 inches rainfall event over a 72 hour period. The facility has an overflow pipe that directs excessive RO volume to a nearby catch basin on the corner of Cherry Alley and Freeport Street.


ECO Park Rain Garden

For several years, the corner lot at the intersection of Wilson St. and Grant Ave. sat vacant and abandoned. However, when the Borough of Etna came into recent ownership of the property, we teamed up to transform the site into a beautiful, green parklet for all in our community to enjoy. Etna Borough Public Works removed asphalt from the rear of the site and brought in compost to start soil remediation. To aid in storm water management, a 900 square foot rain garden with 250 square foot drainage swale (1/3 of the total site) was installed. We were also able to plant four large trees with the assistance of Tree Pittsburgh and community members. And just before temperatures dropped, volunteers came together to construct a shadow box fence and rain garden barrier to enhance and protect the site. 

437 Butler St., Pittsburgh, PA 15223   I      (412) 781-0569



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