Item No.: 8j_supp
Date of Meeting: October 14, 2025

East Waterway Cleanup
Design Authorization
October 14, 2025 - Commission Meeting
Presented by:
Brick Spangler - Sr. Env Program Manager
Tim Leonard - Capital Project Manager

Action Requested
Request Commission authorization for the
Executive Director to complete the remedial
design; including the procurement of a
consultant designer and preparation of
construction documents; for the East Waterway
Cleanup project.

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Eastthe
Waterway
Cleanup Location
Save
Date!

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Project Overview
Save the Date!
The East Waterway cleanup project will involve
removal of contaminated sediment, that poses an
unacceptable risk to human health and the
environment, within 121 acres of the East Waterway
Superfund Site. The first step will be the completion of
the Remedial Design required per an Order issued by
the EPA.
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Primary Parties
• Port of Seattle - the lead contracting agency for
the remedial design
• East Waterway Group (EWG): Port of Seattle,
City of Seattle, King County will implement the
cleanup with oversight from EPA and will share
costs
• EPA - regulating agency
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Stakeholders
• Muckleshoot and Suquamish Tribes - usual and accustomed
fishing/harvesting area with treaty rights and is consulted by EPA
• Washington State Department of Natural Resources (DNR) -
manager of state-owned aquatic lands in EW
• Washington State Department of Ecology (Ecology) -
provides input on state cleanup rules and source control
• Local Residents and Community Groups - Duwamish River
Community Coalition (DRCC) and others have expressed interest
in the cleanup process

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Funding
• The total request for this action is in the amount of $0 as
funding for the required remedial design was included in the
previously authorized 2025-2029 Environmental Remediation
Liability (ERL) Program
• Remedial design effort estimated to cost $30 million including
anticipated $15 - 22 million consultant designer procurement
• Total project cost preliminarily estimated to be approximately
$600 million
• Reimbursement by the City and County of 1/3 each
(subject to reallocation) per EWG MOA
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Preliminary Estimated Schedule
Activity

Timing

EPA ASAOC finalization

October 2025

Design (up to 5 years)

2026-2031

Cleanup construction
(7 - 10 years)
Long-term monitoring

2031-2041
2041 onward
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Remedial
Save
the Date!Design Scope (1 of 2)
• Further data gathering and analysis: collect additional data on
contamination and site conditions to refine the scope of cleanup.
• Detailed engineering design: develop comprehensive plans and
specifications for the selected remedial technologies, including
dredging, capping, in-situ treatment, and enhanced natural
recovery, according to the Interim Record of Decision.
• Specification of cleanup areas: delineate precise areas that
require cleanup based on established remedial action levels.

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Remedial
Save
the Date!Design Scope (2 of 2)
• Development of construction plans: create detailed construction
plans, including sequence of operations, equipment requirements,
and schedules, considering factors like in-water work windows to
protect sensitive species like migrating salmon.
• Waste management planning: determine disposal methods for
dredged and treated contaminated materials.
• Long-term monitoring and maintenance plans: establish
protocols for post-remediation monitoring to ensure effectiveness
and long-term protectiveness of the remedy and maintaining
remediation infrastructure.
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Questions?

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