
COMMISSION AGENDA – Action Item No. 8b Page 2 of 6
Meeting Date: February 13, 2018
Template revised September 22, 2016; format updates October 19, 2016.
jurisdiction over the NWSA North Harbor managed properties and Port of Seattle properties
and facilities.
In 2016, the Utility began collecting drainage fees to be used for a comprehensive investigation
and assessment of the stormwater infrastructure, and to pay for system rehabilitation.
Terminal 18 is at the forefront of system rehabilitation due to the system size, importance to
the container shipping network, and the requirement for improved treatment systems for
industrial stormwater, which the tenant is in the process of installing in a number of upland
basins.
There are 13 outfalls located at Terminal 18, installed in the 1960s and 1970s, which are owned
and maintained by the Port. Given the age of the systems, the outfalls have performed well
over the years; however, there are a number of deficiencies that need to be addressed to
protect the Port’s assets and help protect the water quality of Puget Sound.
DETAILS
Most of the 13 outfalls located on the East Waterway of Terminal 18 have non-functioning or
missing tide gate valves, several of the pipes are broken where they pass through the bulkhead,
and other pipes have settled, causing ponding to occur within the pipes. This project will repair
the broken pipes, correct the grade issues, and install new tide gate valves.
Benefits of this project include maintaining the integrity of the environmental controls
established by the Superfund record of decision. Additional benefits include preventing
infiltration of groundwater and flow of tidal waters into the stormwater system, protecting the
water quality of the East Waterway; reducing corrosion within the pipes from corrosive ocean
salt water; reducing maintenance and cleaning within the stormwater pipes; and contributing
to meeting Century Agenda Strategy 4, Objective 13 – Meet or exceed agency requirements for
stormwater.
Close coordination with the tenant is required for the outfall construction activities to address:
1) Tenant terminal operations and variabilities in shipping schedules; 2) Installation of tenant
stormwater treatment system in close proximity to the outfalls; 3) Unknowns associated with
excavating within an EPA Superfund site. To achieve this close coordination, and reduce project
uncertainties in cost and schedule, we recommend using Port crews, and project specific and
small works contracts to execute the work.
Additionally, due to the close proximity of one outfall to the tenant installed treatment system,
the repair of that outfall will be accomplished by the tenant contractor and reimbursed under a
letter of agreement with the tenant.