THIN LAYER CAPPING
Thin Layer Cap Pilot Project Construction Completed
The Remediation Trust has finished placing clean sand on intertidal flats near the Orrington Picnic Park for the Thin Layer Cap (TLC) Pilot project, which launched mercury cleanup in Penobscot River Estuary sediment.
Four to six inches of sand were spread on 6 acres of intertidal sediments during the TLC Pilot project work that was completed September 3.
Thanks to everyone who joined us August 26 at the Orrington Picnic Park for the community drop-in. We appreciate you taking time to observe the capping and learn about the TLC Pilot. Your interest and engagement are important to our work.
For the two weeks of capping, the operation was visible from the Orrington Picnic Park during the 2-hour windows before and after high tide--depending on weather, tides, and unexpected conditions.
The pilot goals are to demonstrate that a thin layer cap is stable over time, effectively reduces exposure to mercury in intertidal flat sediments, and creates a clean zone for organisms to thrive in.
Cap performance and ecosystem impacts will be monitored for 3 to 5 years after construction. The results will be used to evaluate the feasibility of court-approved, full-scale capping between Orrington and North Bucksport. See the TLC pilot fact sheet linked here.
STAY INFORMED
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Visit this webpage to keep up-to-date about monitoring of the TLC Pilot work.
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Sign up for our email updates—complete the form in the footer below.
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Call our 24-hour hotline to hear recorded updates: (207) 352-3122
CONTACT
Lauri Gorton, Remediation Trust Program Manager, (414) 732-4514, LG@g-etg.com
Greenfield Penobscot Estuary Remediation Trust LLC—the court-approved Trustee of the Penobscot Estuary Mercury Remediation Trust (Remediation Trust)—is managing the TLC Pilot project and other work related to cleanup of mercury in the river.
ORRINGTON PICNIC PARK
Visit the riverfront Orrington Picnic Park located off State Route 15 (River Road) about a mile south of Center Drive in Orrington to see our kiosk for more capping information.
FACT SHEETS
Thin Layer Cap Pilot Project Construction, August 2026
Thin Layer Cap Pilot Project, updated January 2025
THIN LAYER CAP PILOT PERMITS
Department of the Army Permit issued by the U.S. Army Corps of Engineers (USACE), June 2026
Bathymetric Survey Investigation Report, Orrington Reach Capping Remedy, December 2024
Thin Layer Cap Pilot Project Work Plan, Orrington Reach Capping Remedy, May 2024
River Flow Velocity Monitoring Investigation Report, Orrington Reach Capping Remedy, March 2024
Sediment Pre-Design Investigation Report, Orrington Reach Capping Remedy, March 2024
Sediment Pre-Design Investigation Report, Appendix C (Laboratory Reports), March 2024
Sediment Pre-Design Investigation Work Plan, Orrington Reach Capping Remedy, August 2023
Thin Layer Cap Design Work Plan, Orrington Reach Capping Remedy, July 2023
Coastal Wetland Assessment Plan, Orrington Reach Capping Remedy, July 2023
Bathymetric Survey Work Plan, May 2023
Field Sampling and Analysis Plan, May 2023
Quality Assurance Project Plan, May 2023
Health and Safety Plan, March 2023
River Flow Velocity Monitoring Work Plan, Orrington Reach Capping Remedy, March 2023
PRESENTATION