Portland Harbor Dredge & Cad cell project
Scientists, environmentalists, businesses, lobstermen, government agencies and other stakeholders have been working together to find an environmentally and financially responsible solution to the dredging dilemma
Highlights of their work include:
Normandeau Associates analyzes dredge placement options for Portland Harbor.
TIGER grant application lays out the waterfront revitalization strategy for Portland Harbor.
In a collaborative effort to advance the pier dredging initiative, the cities of Portland and South Portland form a Non-Federal Dredge (NFD) work group to assess and recommend options for the placement of contaminated sediments.
The NFD work group recommends that the city issue a Request for Proposal (RFP) for the design and permitting of a Confined Aquatic Disposal (CAD) Cell in Portland Harbor. The recommendation for CAD cell arose because The United States Army Corps of Engineers (USACE) and U.S. Environmental Protection Agency (EPA) will not allow contaminated sediements to be placed at sea. Based on past testing, most of the sediments involved in this project will not likely meet these qualifications.
View Location Sub-group Notes
The Portland Harbor Commission applies for a $350,000 federal Brownfields grant, which would provide the funding necessary for the testing and permitting phase for the dredging project.
The State of Maine Department of Transportation allocates $250,000 to the City of Portland to fund the design and permitting of a CAD cell in Portland Harbor.
The Harbor Commission is awarded the federal Brownfields grant and hires Campbell Environmental Group to complete design and permitting for the dredging of the Portland and South Portland wharves.
The City of Portland issues a Request for Proposal (RFP) for the design and permitting of a CAD cell in Portland Harbor.
Stantec is awarded the CAD cell project contract.
A CAD cell work group composed of approximately 30 Portland Harbor stakeholders is formed to review the site recommendations made by the Non-Federal Dredge work group and provide additional insight regarding possible locations.
CAD Work Group Website
Stantec creates revised scoring matrix based on new site analysis, selects Site C for further testing.
View Site Map and Scoring Matrix
The project team completed a bathymetric survey of Portland Harbor to aid in determining dredge need and associated dredge volumes.
The project team completed a sub-bottom profile survey of proposed CAD Site C to determine depth to bedrock. Based on survey results, Site C has sufficient depth to bedrock for a CAD cell.
Stantec completed a geotechnical boring at the proposed CAD Site C to determine depth to bedrock and sediment characteristics. The geotechnical boring determined depth to bedrock was over 70 feet below the mud line and the bulk of the sediments consist of marine clay. These results indicate that this site is suitable for construction of a CAD cell.
The project team completed initial outreach to waterfront, pier and marina owners to get feedback on dredge need. Based on this feedback and results from the bathymetric survey, dredge footprints and volumes are being calculated.
The project team initiated consultation with MEDEP and USACE on a sediment sampling program for both the dredge areas and CAD cell. Sampling is projected to occur this fall.
Working with the Lobster Fishing Community
The lobster fishing community was engaged early in the Non-Federal Dredge process. Project proponents discussed the potential for a CAD cell at several “Lobster Zone Council Meetings” run by the State of Maine Department of Marine Resources. This early involvement and buy in from the lobster fishing community was important for two reasons.
Firstly, many of the piers degraded by sedimentation are critical to the lobstering economy for berthing, bait, gear storage and support industries.
Secondly, if done poorly, dredging has the potential to impact the fishery and lobster gear.
The project team continues to work with the lobster fishing community to minimize impacts and find the proper CAD cell site so that the dredging of piers and a CAD cell in Portland Harbor benefits the lobster industry and the families that it supports.