Sunken Meadows Salt Marsh Restoration

The Anchor QEA–Princeton Hydro team was selected by Audubon New York (and its partners Save the Sound and New York State Parks) to design the restoration and enhancement of an approximately 400-acre tidal marsh on the north-central coast of Long Island. The marsh has experienced restricted tidal flow since an earthen berm was breached in 2012 during Superstorm Sandy. The restricted tidal flow led to marsh degradation, which converted portions of the former salt marsh to brackish and freshwater marsh. The lack of tidal flushing also enabled invasive Phragmites australis to establish and spread within the marsh system.

Design goals included:

• • Developing viable habitat for the vunerable Saltmarsh Sparrow (Ammodramus caudacutus)
  • Restoring low and high salt marsh habitat
  • Enhancing & providing resilience to existing marsh vegetation
  • Hindering the propagation of invasive species
  • Improving marsh drainage
  • Supporting potential for development of sea-level fen habitat
  • Improving overall coastal resiliency of the site in response to sea level rise

The Anchor QEA–Princeton Hydro team developed 60% Designs, including design drawings, a cost estimate, a long-term management plan, and a QAPP. The project design includes dredging approximately 15,000 cubic yards of material from Sunken Meadow Creek and thin layer placement of dredged material onto adjacent marsh cells to develop low and high marsh footprints; treating approximately 20 acres of Phragmites australis and phased replanting the areas with native species; creating approximately 2,000 linear feet of channels in the marsh and improving approximately 8,500 linear feet of existing channels to enhance drainage and tidal flushing; creating tidal pools and installing anchored rootwads to promote habitat diversity; modifying existing culverts within the primary flow channel through the marsh; and planting within the high and low salt marsh footprints.