Maintenance Dredging – Gales Ferry CT

OLYMPUS DIGITAL CAMERAClient: The Dow Chemical Co.
Allyn’s Point Plant
Gales Ferry, CT
Completion Date: 2006
Actual Project Value: $1,500,000

Relevant Project Features:

  • Developed Sediment Sampling Plan
  • Prepared DEP and Corps Permit Applications
  • Prepared Plans and Specifications for  Bidding and Construction
  • Provided Construction-Observation

RT Group, Inc. (RTG) was retained by the Dow Chemical Company, Allyn's Point Plant to prepare Maintenance Dredging Plans and obtain all local, state, and federal permits for dredging about 100,000 cubic yards of accumulated sediment within their Ship Berth and Turning Basin. Maintenance Dredging was required to maintain safe access to the Allyn's Point Plant fixed timber pier located on the Thames River. Safe access is required to allow sea going vessels/barges to continue offloading raw material at the pier.

RTG worked closely with the US Army Corps of Engineers (Corps) to develop the Sediment Sampling Plan and collected the sediment samples in the field.

OLYMPUS DIGITAL CAMERAThis field effort included collecting sixteen (16) vibrocore samples from a work barge and submitting the sediment samples to a laboratory for both chemical and biological testing. The vibrocore samples ranged from about 5 to 12 feet in length and were collected in about 20 to 25 feet of water.

The chemical and biological testing was completed in 2002/2003 and included both 10-day toxicity testing and 28-day bioaccumulation testing.

Following the testing, RTG submitted the Connecticut Department of Environmental Management (DEP) Certificate of Permission (COP) application and the Corps Individual Permit application to complete this project. A summary of the testing results was submitted to the DEP and Corps in advance of submitting the permit applications.

In June 2004, RTG obtained the DEP and Corps permits to complete this project and worked with Allyn's Point Plant personnel to obtain all local approvals. Based on the testing results, dredged material was approved for disposal at the New London Disposal Site within Long Island Sound. In October 2006 the dredging project was completed and about 100,000 cubic yards of material was removed.  RTG provided construction observation during dredging, including staffing the project with Corps Certified On-Board Inspectors.  RTG also performed the Pre-, During-, and Post-Dredge Surveys for the Contractor that completed the project.