AVALON – In 2019, the U.S. Army Corps of Engineers announced the formation of the Seven Mile Island Innovation Laboratory (SMIIL), an initiative aimed at improving marsh restoration and resiliency.
One focus of the effort was the beneficial use of dredge materials. Avalon and the Wetlands Institute were early participants in the effort.
Wetlands Institute Executive Director Lenore Tedesco Oct. 13 reported to Avalon Borough Council on SMIIL’s successes and the paradigm shift in the use of dredge materials.
For years, the accepted view of dredge materials was that they were to be removed from the marsh. Trucks lumbered off the island following dredging of the back bay channels and slips.
Finding a location that would accept the spoils of a dredging effort became one of the more difficult and expensive aspects of efforts to clear the waterways.
Tedesco told the council this month that her job was to convince them to keep the dredge materials in the marshes, not truck them out. She spoke of the many alternative placements for dredge materials, as part of creating healthier and more resilient wetlands.
In simple terms, the marshes are drowning. Although the tidal marshes adapt to the ebb and flow of the tides, sea-level rise is extending the frequency and duration of flooding faster than the marshes can adapt. The marshes are losing sediment, becoming casualties of climate change.
Dredge materials should no longer be trucked to containment facilities.
Emerging techniques, like those researched in SMIIL, now call for clean, nontoxic sediment to be kept in the marshes, as part of the marshes’ natural protection against sea-level rise. The trick is to find where the sediment is most needed and relocate appropriate dredge materials to those locations.
Noting that the mean high-water mark for Avalon marshes is 2 feet, Tedesco presented a map showing the locations in Seven Mile Island marshes where the buildup of the marshes was a critical necessity.
Tedesco also spoke of a new “pathway to permitting” for dredging efforts as they incorporate notions of marsh build-up and increased resiliency.
Borough Business Administrator Scott Wahl said the shift to retaining dredge materials in the marshes may help the borough’s effort to obtain a boroughwide dredging permit, allowing the borough to aid in maintaining navigation of the waterways, while also supporting greater resiliency and environmental restoration of the wetlands.
To contact Vince Conti, email vconti@cmcherald.com.
