Abstract: Session A  10:10 am (BACK)

Post-Storm Infrastructure Improvements and Stream Restoration: Three Case Studies

Thomas A. Graupensperger
Carlisle, PA

Hurricane Sandy, Tropical Storm Lee, and numerous unnamed, isolated, high-intensity, short-duration storm/flood events have resulted in major infrastructure damage in recent years. This session will present case studies for three projects that improve resiliency and sustainability of vulnerable infrastructure by using Natural Stream Channel Design and Restoration techniques.

We will look at opportunities where infrastructure rehabilitation and replacement are paired effectively with stream restoration activities. Such projects include roads; bridges; culverts; sewers; storm sewers/outfalls; other utilities and green infrastructure; park, recreation, and trail facilities; and the creation, restoration, and reconnection of natural resources including floodplains, wetlands and riparian habitat.

Understanding the storm event, failure mechanisms, and associated existing/pre-existing conditions associated prior upstream alterations is critical to determining the appropriate restorative measures that will survive severe weather events. In order to predict and model proposed stream restoration treatments and required scour countermeasures, we need to understand and evaluate a project area’s underlying geology, soils, stream channel morphology, watershed hydrology, and local hydraulic (scour) characteristics.

We will review the following case studies which are located in different physiographic provinces with varying watershed and site-specific hydrogeologic and severe weather event characteristics:

  • SR 2075 Bridge Replacement, Muddy Creek Tributary to the Susquehanna River, York County, PA
    Lower Piedmont, confined valley/deep alluvium, historic alterations constrained by former railroad and roads.
  • Oakwood Beach Flood Attenuation, Mill Run Tributaries to Lower Bay, Staten Island, NY
    Lower Coastal Plain, glacial outwash and coastal sands, stormwater outfalls and sanitary sewer lines.
  • SR 1003, Bridge Replacement and Embankment Reconstruction, Wallis Run, Tributary to Loyalsock Creek, Gamble Township, Lycoming County, PA  Alleghany front, glacial outwash and deposition.

Case studies will identify site constraints, TMDL development opportunities, and restoration approaches and considerations. Construction modifications, means, and methods, as well as best practices will be presented to assist attendees in identifying similar concerns during their projects.