A.D. Marble developed preliminary design and final construction plans and specifications for two reaches of stream restoration as mitigation for impacts related to the total reconstruction of the Pennsylvania Turnpike between the Harrisburg West Interchange and the Susquehanna River Bridge in York County, Pennsylvania. The goals for the compensatory mitigation plan were to restore and enhance a tributary to the Yellow Breeches Creek impacted by historic straightening and livestock grazing, and increase water quality within the watershed. The ecological objectives associated with these goals are provided below:

• Restore and enhance approximately 2,815 linear feet of streambank stabilization and natural stream restoration.
• Improve the water quality of the stream by restricting livestock access, reducing direct runoff from pasture to Yellow Breeches Creek, and reducing sediment input from eroding streambanks.
• Improve riparian cover and function by creating a conservation easement, restoring 50-foot riparian buffers along the streambanks.
• Improve floodplain connectivity of vegetated stream corridor by creating floodplain benches.

A.D. Marble also provided construction consultation and oversight on the project.

A.D. Marble was awarded an American Council of Engineering Companies Diamond Award for Engineering Excellence in 2019 for the design of the wetland and stream mitigation site.