McCormick Taylor led a complex wetland and stream mitigation plan as a subconsultant during the Final Design and Construction of the SR 322-B06 Potters Mills Gap (PMG) Transportation Project.



The PMG Transportation Project was a priority under the Pennsylvania Act 89 Comprehensive Transportation Funding Plan focused on addressing safety, congestion, and access issues while minimizing impacts to environmental and historic resources. The corridor, located in Centre County Pennsylvania, weaves through the village of Potters Mills, Bald Eagle and Rothrock State Forests, and bisects the Pennsylvania Department of Conservation and Natural Resources’ (DCNR) Penn Nursery. The project area included numerous sensitive environmental resources which included high quality-cold water (HQ-CWF) streams, such as the wild trout Class A Potters Run, and exceptional value wetlands. While the project avoided sensitive features where possible, stream and wetland impacts required compensatory mitigation.

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Pre-construction Fire Pond area
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Post-construction Fire Pond area
pmg 2a pre construction pond
pmg 3a post construction stream with habitat logs
pmg 3b post construction wetland snag habitat


McCormick Taylor, working with the Pennsylvania Department of Transportation (PennDOT) Engineering District 2-0, initiated a stream and wetland mitigation plan during Final Design. One of the locations the plan focused on was the site of the Fire Pond stream and wetland mitigation site.


The site is located on DCNR property at the Mira Lloyd Dock Resource Conservation Center. The pond was approximately 1.5 acres in area by 7 to 8 feet deep and historically served as a water source in the event of a fire at the local Wood Shop. Since the pond was no longer needed for that purpose, the design approach consisted of draining the existing pond, restoring the original stream channel and converting it to a wetland and stream ecosystem.


The project stream is an unnamed tributary to Potter Run. Potter Run is classified as a Class "A" Wild Trout Stream by the PA Fish and Boat Commission, indicating the presence of naturally produced trout that support a rewarding sport fishery. The stream design included riffle habitat structures (with embedded logs), floodplain benches, and minimized rock on the streambanks.


The wetland elevation was set approximately five feet higher than the stream/floodplain to maintain wetlands located along the fringe of the pond footprint. This approach was a requirement from the permitting agencies. In addition to mitigation, this project was important to the resources agencies as it removed a source of elevated water temperature within the Potter Run watershed.


Construction was unique due to the pond setting and the proposed differences in elevation between the stream/floodplain and wetland. This required draining the pond, removing the dam/embankment, multiple pump locations for maintenance of streamflow, removing unconsolidated/mucky sediment from the pond bottom, furnishing and compacting large amounts of fill to construct the proposed grade, frequent testing of material and compaction, and flexibility to work within the project setting.


Construction of the stream and wetland mitigation site was completed between January and March of 2019, and post­construction monitoring was initiated in fall of 2019 and completed Fall 2021.



pmg 1a pre construction pond
Pre-construction Fire Pond
pmg 1b post construction wetland
Post-construction wetland