Dec 04, 2018

Suburban Pennsylvania Town Benefits From Green Infrastructure

Green infrastructure provides storm water benefits to Pennsylvania town

As a regulated municipal separate storm sewer system (MS4) in the Chesapeake Bay watershed, the city of Lancaster, Pa., was obligated to meet pollutant reduction requirements. After selecting Shelley Road, a flood-prone street in the city’s southeast annex, the city partnered with RGS Associates to develop a green solution that uses best management practices (BMPs) to meet nutrient reduction goals while contributing to local neighborhood aesthetics.

The final design incorporates micro bio-retention areas, permeable pavers, an underground storage reservoir and a regenerative step pool conveyance system. These improvements provide storm water volume control and water quality improvements, while minimizing erosion to an unnamed Conestoga River tributary.

However, during the conceptual design phase some residents were skeptical that the proposed Shelley Road green infrastructure plan would be effective in a suburban neighborhood. In the initial design stages, residents voiced concerns regarding motorist safety and loss of on-street parking spaces. Implementing green storm water solutions at Shelley Road involved effective collaboration and communication between the city of Lancaster, RGS Associates and the community.

“While our initial collaboration could best be described as ‘intense’ due to some neighborhood skepticism, it quickly became one of good will following educational meetings, one-on-one conversations, and other outreach efforts,” said Len Bradley, associate for RGS Associates; Ruth Hocker, the city’s storm water program manager; and John Hershey, associate for RGS Associates together.

After effective communication and the successful implementation of the design, residents became supportive of the project, which is a point of pride for Hocker who said residents have taken ‘ownership’ of the project despite previous resistance. Following implementation, city staff even received numerous calls from formerly opposed residents complimenting the project.

An additional challenge the team encountered was that the street’s drainage point was more than 6 ft higher than the tributary which it drained into. Combined with high runoff velocities, this led to a highly eroded drainage channel and frequent sedimentation. To address this issue, the design included BMPs to slow and treat the storm water runoff, as well as a regenerative conveyance system that incorporates a series of stepped bio-retention plunge pools and stone riffles that reduces the energy of storm water discharge to a non-erosive condition.

Since completion earlier this year, Shelley Road’s green infrastructure has performed well during two wet seasons and contributes to pollutant reductions. The project serves as an effective model for other older suburban neighborhoods in the region with similar challenges.

Project Year:
Contractor: Rogele Inc.
Designers: RGS Associates Inc.
Solution Providers: Advanced Drainage Systems, Laurel Valley Soils, East Coast Erosion Control, Monarch Precast, Pavedrain, Filtrexx
Owner: City of Lancaster, Pa.
Location: Lancaster, Pa.
Cost: $253,000
Size: 2,052,228 gal per year