Pennypack Ecological Restoration Trust Stormwater Wetland


The T-VSSI researchers installed a Stormwater Wetland and associated Riparian Buffer along Terwood Run, south of the Inverness Road bridge at the Pennypack Ecological Restoration Trust (PERT). PERT is located within the Pennypack Creek Watershed. The researchers chose the location to install the stormwater wetland at PERT because it is at a topographic low point, receiving stormwater runoff from an area of approximately 10 acres. It lies within the floodplain of Terwood Run and the depth to shallow groundwater was near enough to the surface to support wetland vegetation. Of the 10 acres that lie upgradient from the wetland, about 30% are impervious and the remainder is either forest or mowed grass lawn (about a 50:50 mix of each).

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Video Feature

Executive Summary

During the summer of 2006, the T-VSSI team constructed a Stormwater Wetland at the Pennypack Ecological Restoration Trust (PERT). The wetland is approximately one-half acre in size flanking the western bank of Terwood Run with a storage capacity of 20,000 cubic feet. Designed to capture surface stormwater flows from an upland drainage area of about 10 acres, the wetland will also capture and dampen stormwater flows that overflow Terwood Run’s western bank. Through retention and infiltration, the BMP reduces downstream stormwater volumes, stream bank erosion, and non-point source pollution. The site was planted with native species and wetland vegetation following completion of construction. During the 1-year post-construction monitoring in the Spring 2007 the research team determined that the site needed to be replanted due to plant extinction from deer grazing and extreme weather. The research team will develop a revised planting plan and replant this test site.

Initial Planting Diagram 2006 (pdf)
Replanting Diagram 2007 (coming)
Replanting List 2007 (coming)

Design Goals

  • Capture stormwater related stream bank overflow
  • Retain stormwater
  • Evapotranspirate stormwater
  • Capture sediment
  • Archive wetland structure and function


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