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Abstract: Session F  4:30 pm (Back to Session F)
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Stream Restorations for Improved Resilience and TMDLs

Thomas A. Graupensperger
Dewberry
Mechanicsburg, PA 

 This session will present project examples that improved resiliency of vulnerable, extreme event impacted infrastructure by using Natural Stream Channel Design Stabilization and Restoration techniques. Extreme weather events have continued throughout 2018, with record rainfall amounts in many locations throughout Central Pennsylvania and surrounding Mid-Atlantic regions. How can we design for these more numerous and more extreme events in the future, while mitigating increased storm/flood flows, volumes and meet water quality requirements?

We will look at opportunities where gray and green/nature based infrastructure rehabilitation and replacement are paired effectively with stream restoration/stabilization activities for improved resiliency. By effectively integrating resilient gray and green/natural-nature based infrastructure improvements; the creation, restoration, and reconnection of natural resources (floodplains/wetlands/riparian buffers/aquatic habitat) for triple bottom line benefits including TMDL credits and continued opportunities for pollution reduction within the Chesapeake Bay and other watersheds.

We will review Marsh Run Stream Restoration, a direct tributary to the Susquehanna River.

Working with the Defense Logistics Agency (DLA) to develop Access Point Security Upgrades involved stream restoration-floodplain reconnection construction in prior filled floodplains on first and second order stream channels.

Design-Build construction modifications, means, and methods, as well as best practices will be presented. Lessons Learned through post-construction monitoring, inspection and identification of adaptive management measures will be outlined and include:

·       Conflicting green/gray infrastructure improvements/opportunities; specifications and implementation challenges;

·        Design-Build Advantages and Disadvantages;

·       Post construction weed related issues;

·       Nuisance/invasive species, short and long-term control plans and floodplain soils modifications
through floodplain reconnection/wetlands, riparian buffers, and reforestation;

·        Herbivory related issues;

·       Developing storm-flood resiliency while restoring/stabilizing eroded, sediment producing outfall
channels;

·       Water quality improving floodplain wetland development opportunities.

 The presentation will revisit and provide an overview/review of the SR 1003, Bridge Replacement and Embankment Reconstruction, Wallis Run, Tributary to Loyalsock Creek, Lycoming County, PA and outline site hazard mitigation, restoration approaches implemented:

 ·       Extreme event resiliency through redundant measures

·       Flood/Shear Vulnerability Assessment/Analyses

·       Proactive vs Reactive Channel Instability Restoration/Hazard Mitigation

·       Hydrologic Mitigation-(Reduce/Delay/Desynchronize Peak Flows) with Floodplain Reconnection/Wetlands/Forest
Buffer/Reforestation

·       Local & Regional Sediment Management/Transport

·       Habitat restoration and enhancement.