PORT OF SEATTLE 
MEMORANDUM 

COMMISSION AGENDA                   Item No.:          7a 
STAFF BRIEFING 
Date of Meeting:      December 7, 2010 
DATE:      November 30, 2010 
TO:         Tay Yoshitani, Chief Executive Officer 
FROM:     Mike McLaughlin, Director, Cruise and Industrial Properties 
Mark Griffin, Senior Manager, Real Estate Development 
SUBJECT:   King County Proposal for Locating Combined-Sewer Overflow Facility on Port
of Seattle Property 

BRIEFING OUTLINE: 
The Commission will be briefed by Port and King County staff on King County's plan for
controlling combined-sewer overflows, the public process to review potential sites, and their
selection of preferred sites. A representative of the City of Seattle will be available to discuss the
city's interests in the site selection and potential park development. 
BACKGROUND: 
Earlier this year, the King County Wastewater Treatment Division approached the Port of Seattle
with proposals to construct facilities in the vicinity of the port's West Yard at Terminal 91 for
control of combined stormwater and wastewater. 
The county is planning and constructing a series of facilities to control overflows from the older
combined sewer and stormwater systems throughout its system. Throughout the City during
periods of heavy rainfall, stormwater flows can exceed system capacity, leading to spills of
untreated sewage into Puget Sound and other local waters. The county is under a deadline set by
the state Department of Ecology to reduce significantly these combined-sewage overflows
(CSO). 
In the Magnolia basin, sewage overflows occur 19 times a year on average, totaling 31 million
gallons annually. To control overflows in this basin, the county considered a number of sites in
the Magnolia area. Following a public comment process, the county narrowed the list to a citypark
site and two design concepts on port property: 
A 1.8-million-gallon underground tank and an above-ground structure, and piping to
connect to the conveyance system in the West Yard. 
An in-line storage system that would involve a large-diameter underground pipe 
traversing Terminal 91uplands east to west.

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
November 30, 2010 
Page 2 of 3 

Port staff concluded that the underground storage facility warrants further consideration, under
certain circumstances described below. Construction of the large pipe concept across Terminal
91 is not recommended as it would disrupt upland operations and unduly restrict future business
opportunities. 
The county's proposal comes as the port is starting a planning effort to study the long-term
development potential for the Terminal 91 uplands and certain under-utilized property south of
the Magnolia Bridge, including the West Yard. In addition, the port and the City of Seattle's
Department of Parks and Recreation have conducted preliminary discussions in the past about a
land swap of the Port's West Yard and Smith Cove Shoreline Public Access site for the city's
adjacent playfield known as Smith Cove Park.
In the context of the county proposal, the trade offers potential benefits for the port, the city,
county and community. The port would gain property with better access and development
potential. The city would gain a more attractive park site bounded on two sides by water. The
underground storage tank would be suitable for a park site, but would severely limit aboveground
industrial or commercial development.
The port, city and county representatives briefed the Neighbors Advisory Committee on the
proposed CSO facility and land swap on October 20, 2010. At that meeting, the NAC approved
a resolution supporting the tank proposal on the condition the land swap and park development
occurred in the West Yard area. 
The port is engaged in discussions with both the city's Parks and Recreation Department and the
county to determine if a mutually beneficial agreement can be accomplished. On a preliminary
basis, staffs have agreed to examine the potential of locating the tank in the general vicinity of
the West Yard and the city's park property, termed the Lower Basin. The configuration of the
tank and associated equipment, as well as details of the land swap, is still under discussion. 
Staff is currently negotiating a memorandum of agreement (MOA) that describes responsibilities
and deadlines for determining the feasibility of the proposal. The draft agreement calls for a
decision by the three parties on a site for the tank by February 15, 2011, to be followed by
negotiations on design, compensation and mitigation. 
Property transfers and easements for the land swap and tank construction would be subject to
approval by the Port Commission and the Seattle and King County councils. 
NEXT STEPS: 
The county, city and port will negotiate an MOA for approval by the Port Commission and
signature by the Chief Executive Officer and respective officials of King County and the City of
Seattle. The MOA will not commit any port property or action but will describe the process for

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
November 30, 2010 
Page 3 of 3 
reaching a decision among the parties. Staff will return to the Commission in early 2011 for
further updates on the discussions. 
OTHER DOCUMENTS ASSOCIATED WITH THIS BRIEFING: 
Site photo 
King County PowerPoint presentation