Triangle Park Stormwater Management Techniques

Description

Nutrient and sediment-laden Crum Creek has been listed as an “impaired” body of water under the Clean Water Act. This is due to high impact development and conventional stormwater management methods like drains, sod basins, and concrete swales, which simply convey rapid stormwater runoff directly into creeks and rivers. Prior to the implementation of this project, there was no stormwater management infrastructure in place at Triangle Park, exacerbating the problem of both flooding and pollution. The flat area of the park and its surrounding streets created huge quantities of runoff, which had been known to sweep away mulch from Triangle Park’s playground. There were no stormwater sewers in the vicinity of the park and water flowed straight down the avenue gutters. The park’s closest outlet drain was located 500 ft. from the park on Swathmore Avenue. Conceptual retrofit design recommendations included building a porous asphalt basketball court, an underground infiltration gallery, a rain garden, a vegetated water quality channel, a diversion berm around the playground, and another subsurface infiltration tank under grassy areas.

The stormwater Best Management Practices (BMPs) at Triangle Park that Rutledge Borough implemented or is planning to implement include a Porous Asphalt Basketball Court and Underground Infiltration Facility and a Rain Garden. The underground infiltration facility and porous pavement project has been completed, while Rutledge Borough is planning on installing a rain garden in 2009. These enhancements improve water quality, provide wildlife habitat, beautify the park, and effectively manage runoff from storm events.

Porous Asphalt Basketball Court and Underground Infiltration Facility
To reduce water runoff flowing onto Rutledge Avenue, the on-site basketball court was resurfaced with porous surface material. Underneath the court, an 85’ x 85’ underground infiltration gallery was constructed and filled with stone or pipe to hold stormwater. This system maximizes the park’s small space and does not interfere with present amenities. Overall, the system allows for adequate storage of surface water during peak flow times and recharge of underlying aquifers. For a typical diagram of porous pavement layers by Cahill Associates, Inc. click here.

Rain Garden
A rain garden, or bioretention basin, detains and infiltrates stormwater in order to reduce area flooding and mitigate pollution through bioremediation processes. Original topsoil is redistributed, native plants shrubs and trees are planted, and a maintenance plan prevents the growth of invasive species. The addition of a rain garden at Triangle Park will be beneficial to the ecology of the whole watershed region. The design of the basin will allow for several tiered grades to provide for varied microhabitats for moisture-loving plants.  This rain garden will allow sediment to settle and reduce nutrients like fertilizers and oils’ entry into Crum Creek. For a bioretention diagram by Cahill Associates, Inc., click here.

Location

County: Delaware
Watershed: Darby-Cobbs Creek

Triangle Park is on 2.5 acres between Swarthmore and Rutledge Avenues in suburban Rutledge Borough. The park is located on the more residential side of the Borough.

Partners

Rutledge Borough
Delaware County Planning Department
Delaware County Conservation District
Pennsylvania Environmental Council

Cost

Cost estimates by Borton-Lawson: Impervious surface reduction with subsurface infiltration: approx. $24,000-30,000. Subsurface infiltration facility: approx. $75,850-$95,000. Diversion berm: $9,500-12,000. Vegetated water quality channel: $15,800-19,750.

The concept design recommendations were prepared by Borton-Lawson through funds provided by the Pennsylvania Department of Environmental Protection (PADEP) and the Pennsylvania Environmental Council’s (PEC’s) Stormwater Retrofit Technical Assistance Program, which is funded through a Pennsylvania DEP Coastal Zone Management Program Grant and through the William Penn Foundation.Catania Engineering is hired under contract by the Borough for the final design project.

Contact

Liz Feinberg
Pennsylvania Environmental Council SE Office
123 Chestnut Street, Suite 401
Philadelphia PA 19106
215-592-7020 x113
lfeinberg@pecpa.org

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