LIDAR and drone surveys show rapid dune loss at Plum Island; consultant urges monthly monitoring and proactive sand placements

Tom Hughes presented combined Army Corps photogrammetry, recent drone surveys and local ground surveys comparing fall 2025, early 2026 and post‑storm conditions at Plum Island and Reservation Terrace. Cross‑section analysis showed substantial loss of dune height and beach volume in key sections — in one cross section Hughes estimated a single storm removed on the order of thousands of cubic yards in the nearshore/bulk of the project area.

Hughes said the pattern is strongly influenced by the local jetty, which alters sand transport and creates focused scour along the north‑end configuration. He urged monthly LIDAR flights, additional bathymetry and consideration of temporary mechanical sand placement in targeted areas to create a critical mass of sand before potential structural measures (e.g., a weir) are installed. "If we don't act, the crest drops and then you'll have overwash that can cut through and start to flood the low‑lying areas behind the barrier," Hughes said.

Commissioners discussed funding and coordination options. Hughes said he has private philanthropic support to start data collection and will seek partnerships with the city and regional agencies; he recommended confirming ground control points and sharing high‑quality LIDAR and bathymetric data with the Army Corps to help verify modeling. The commission asked staff to prioritize mapping and follow up on opportunities to coordinate funding or data sharing with regional partners.