Layer by Layer: Building Resilience with Thin Layer Placement

Layer by Layer: Building Resilience with Thin Layer Placement

How can we restore marshes that are slipping away under the pressure of rising waters, stronger storms, and eroding shorelines? One answer may come layer by layer.

At the Elizabeth River Project’s recent symposium on thin layer placement (TLP), hosted in collaboration with the Chesapeake Bay Foundation, Anchor QEA Principal Engineer Ram Mohan, PhD, PE, F.ASCE, delivered the keynote presentation, “Layer by Layer: The TLP Journey.” At this event, funded through a grant from the National Fish and Wildlife Foundation, more than 60 professionals, practitioners, and regulators gathered at the Brock Environmental Center in Virginia Beach to explore how this proven and promising technique can help coastal wetlands adapt and thrive.

TLP works by applying a thin layer of dredged sediment across degraded marshes, raising their elevation just enough to keep pace with the effects of ocean encroachment. Decades of projects across the United States show that when applied thoughtfully, vegetation rebounds within a season or two, ecosystems regain stability, and communities benefit from stronger natural defenses.

In his presentation, Ram shared lessons learned from case studies nationwide, including the following:

• Balance is key. Just 6 to 12 inches of material can spark recovery, but too much can affect marsh regrowth.
• Nature can do the heavy lifting. Both natural reseeding and targeted planting have proven effective in restoring marsh vegetation.
• Smart design pays off. Setting ecological elevation targets and aligning with natural landscapes lead to healthier marshes, lower costs, and longer-lasting resilience.
• Adapt in real time. Successful projects require flexibility on the ground, from moving pipelines to pausing work with the tides.
• Partnerships are essential. Success depends on collaboration among scientists, regulators, contractors, and communities.

As a coastal state, Virginia is representative of both the opportunities and the challenges of TLP. Stakeholders are hopeful, but uncertainties around permitting, funding, and site ownership can lead to apprehension and slow progress. These are common hurdles whenever new or unfamiliar approaches are introduced. Building a community of practice through shared examples, monitoring, and open dialogue is critical to scaling solutions across regions.

The symposium also featured insights from Erin Reilly of the Chesapeake Bay National Estuarine Research Reserve and Steven Shaw of Sevenson Environmental, highlighting the collective expertise driving innovation in this field. Elizabeth River Project’s Ella DiPetto opened the symposium by underscoring TLP as a vital tool to help coastal communities confront rising water levels, stronger storms, and loss of marshlands.

As Ram stressed, adaptive management will be vital: monitoring, adjusting, transferring best practices to future projects, and even, in rare cases, layering again, if needed. With thoughtful application, thin layer placement offers not only a restoration tool but also a pathway to resilience for coastal marshes and the communities that depend on them.

Get in touch with Anchor QEA’s Ram Mohan to learn more about TLP.