Impact of Hurricane Irene on Pivers Island Shorelines Carolyn Currin, NOAA NOS Objective: Provide data on resiliency of ‘living shorelines’ to storm impacts

Installed 6 horizon makers at each PI site, at lower, middle and upper edge Read SETS at PIW (Sill) and PIN (NAT) post –storm Examined hardened structures for evidence of erosion PIE marsh-oyster restoration PIW marsh-sill

NOAA NWLON station Wind speed (mph)

Sediment deposition layer (mm) ElevationPlotPIEPIWPIN Lower NA Mid High Sediment accretion in Pivers Island Marshes Hurricane Irene resulted in net sediment deposition to PI sites

Erosion behind west-facing bulkhead (consistent with R. Gittman assessment of stabilization structures in Bogue Sound) Erosion of bank behind riprap Minimal erosion of unvegetated sediment bank Intact upland border adjacent to marsh

20 yr old Oyster reef – marsh project ‘Dredge Island’ October 2011 post-Irene Conclusion: Marsh – oyster reefs provide an effective shoreline stabilization alternative Additional data on Hurricane Irene impacts to estuarine shorelines South shore of Dredge Island restoration site Dredge Island wave exposure setting Salt marsh Carteret Co. marsh width vs. wave energy

Two other assessments : J. Fear NERRS: marsh sill projects -little damage, wrack deposition -ome adjacent erosion of shoreline R. Gittman UNC: bulkheads, sills, marshes in Bogue & APES -bulkhead erosion more prevalent than marsh erosion

Sill structures showed no damage with marsh intact Some accumulation and sediment trapping by larger structures. Design matters. Bulkheads and upland revetments showed some damage and scour – often overtopped. Slope is important. Unvegetated sediment banks eroded Intact marsh-upland boundaries showed no upland erosion or marsh loss. Oyster reef-marsh shorelines showed no erosion. We documented net sediment gain in Pivers Island shoreline marshes. Summary of observations on Irene impact on shoreline stabilization projects Pivers Island transplanted marsh Oyster cultch addition DMF