PORT OF SEATTLE 
MEMORANDUM 
COMMISSION AGENDA              Item No.      5c 
ACTION ITEM             Date of Meeting    July 9, 2013 

DATE:    July 1, 2013 
TO:      Tay Yoshitani, Chief Executive Officer 
FROM:   Darlene Robertson, Director, Harbor Services, Real Estate Division 
Tracy McKendry, Senior Manager, Recreational Boating Facilities 
Mark Longridge, Capital Project Manager, Capital Development Division 
SUBJECT:  Shilshole Bay Marina Central Seawall Replacement (CIP #C800088) 
Amount of This Request:         $202,000   Source of Funds:         Tax Levy 
Est. Total Project Cost:           $901,000 
Est. State and Local Taxes:         $56,000   Est. Jobs Created:         N/A 
ACTION REQUESTED 
Request Commission authorization for the Chief Executive Officer to complete design for the
rehabilitation of 100' of the Shilshole Bay Marina Central Seawall for an amount not to exceed
$202,000. The total project cost is approximately $901,000. 
SYNOPSIS 
Shilshole Bay Marina (SBM) was built in the late 1950's with the first dock opening in 1960. In
2012, SBM celebrated its 50th anniversary. It is the premier marina in the Pacific Northwest and
the Seattle area providing more than 1,400 moorage slips, approximately 80% of which are 
utilized by sailboats (current occupancy is approximately 98%). The moorage provided is
primarily for long-term recreational moorage with an additional 8,000 guest moorage visitors to
the marina annually. The facility is used not only by recreational vessel owners, both pleasure
and commercial but by commercial fishing and Tribal vessel owners, along with the maritime
businesses that support them. Size of vessels range from small kayaks to mega-yachts.
Shilshole has the largest live-aboard community in the State of Washington. The marina is an
important job and revenue generator in Puget Sound's recreational boating sector (additional
information is provided below).
The central section of the seawall, approximately 100', at Shilshole Bay Marina is nearing the
end of its serviceable life. This 100-foot section of the current seawall was built in 1962 as part
of the original marina construction. See attached photos of the seawall. This is a needed 
infrastructure improvement and there are no incremental revenues associated with this
renewal/replacement project. The project was included in the 2013 Real Estate capital budget
and Plan of Finance. 

Template revised May 30, 2013.

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 1, 2013 
Page 2 of 4 
BACKGROUND 
This section of the seawall was originally under the central pier of the marina, which has since
been removed as part of the redevelopment/replacement of the original docks which was
completed in 2008. It is currently the only section of the seawall composed of timber piers and
lagging (other sections of the seawall are concrete). The existing lagging is showing signs of
distress and needs to be replaced or supplemented. This section of the seawall supports the
northern end of the central plaza and garden area of the marina which is the primary access for
both the fuel float and guest moorage slips of the central docks and is highly utilized by our
tenants, the public and other visitors to the marina. Not replacing this section of the seawall
could lead to localized failures of this retaining structure and significant slope instability. 
The preferred alternative is to replace the existing timber lagging boards with concrete or
composite boards and place steel collars over the existing piles to hold these new lagging boards
in place. A discussion of the alternatives follows. 
Shilshole Bay Marina is the largest marina in Seattle and plays an important role by supplying a
large amount of recreational moorage to the Puget Sound region, by the economic impacts it
generates and by its annual positive cash flow to the Port (Income from Operations) of over
$5,600,000. From the Port of Seattle's 2009 Economic Impact Study (conducted by Martin
Associates), the Port's recreational boating marinas generated almost 400 jobs (direct, indirect &
induced), almost $8 million in local purchases, $14 million in business revenues and over
$2million in state and local taxes, the majority of which is from Shilshole Bay Marina. 
Recreational boaters spend money in various maritime service sectors such as navigational
equipment, sails & sail making, engine services, marine repair, fuel, marine clothing, and many
more. The recreational boating industry in the State of Washington is an approximately $4
billion industry which created 1,923 jobs and generated $31 million in state and local taxes
(taken from the NW Marine Trade Association Economic Impact Study of Recreational Boating
by Herbert Research dated April 2011). 
The overall value of Shilshole Bay Marina is estimated at $62 million.
PROJECT DETAILS 
Project Objectives 
Replace failing or weakened sections of the existing timber seawall. 
Extend the useable life of the central seawall for 30 to 50 years to better match the
redevelopment of the harbor/docks. 
Minimize disruption to the marina customers and available moorage during and after
construction. 
Scope of Work 
This project would complete the design and permitting to rebuild the remaining timber step wall
section (about 100 feet) of the Shilshole Bay Marina central seawall. The current preliminary

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 1, 2013 
Page 3 of 4 
design calls for the removal of the existing lagging and exposing of the existing timber piles,
needed repair and wrapping of the piles and placement of steel collars over the piling. Concrete
or composite lagging would then be placed between the piles to complete the installation. The
optimal means and methods to construct this work will be assessed during the design phase. 
Schedule 
The estimated schedule for completing this work is: 
Design:          July 2013 - Sep 2013 
Permitting:        July 2013 - Oct 2013 
Construction:      Dec 2013 - Feb 2014 
Closeout:         Feb 2014 - May 2014 
FINANCIAL IMPLICATIONS 
Budget/Authorization Summary         Capital      Expense     Total Project 
Original Budget                             0          $0          $0 
Previous Authorizations                   $50,000          $0      $50,000 
Current request for authorization              $152,000          $0      $152,000 
Total Authorizations, including this request      $202,000          $0      $202,000 
Remaining budget to be authorized           $699,000          $0     $699,000 
Total Estimated Project Cost               $901,000          $0     $901,000 
Project Cost Breakdown              This Request        Total Project 
Construction                                     $0          $590,000 
Construction Management                      $18,000          $71,000 
Design                                    $95,000           $95,000 
Project Management                          $71,000          $71,000 
Permitting                                   $18,000           $18,000 
State & Local Taxes (estimated)                        $0           $56,000 
Total                                       $202,000           $901,000 
Budget Status and Source of Funds 
This project was included in the 2013 Real Estate capital budget and related Plan of Finance
under CIP #C800088 SBM Central Seawall Replacement in the amount of $915,000. The source
of funds will be the tax levy. 
Financial Analysis and Summary 
CIP Category             Renewal/Enhancement 
Project Type              Renewal & Replacement

COMMISSION AGENDA 
Tay Yoshitani, Chief Executive Officer 
July 1, 2013 
Page 4 of 4 
Risk adjusted discount rate     NA 
Key risk factors             Condition of current structure may be worse than
preliminary investigation indicated requiring additional
work and higher cost. 
Project cost for analysis        $901,000 
Business Unit (BU)          Harbor Services Group  Shilshole Bay Marina 
Effect on business performance  Annual Depreciation of $30,000.
There are no incremental revenues associated with this
project as it is renewal of needed infrastructure. 
IRR/NPV             The NPV is the present value of the project cost. 
STRATEGIES AND OBJECTIVES 
This project provides for the continuation of a functioning facility to Port tenants in support of
business plan strategies and objectives that call for maintaining real estate assets, not deferring 
maintenance, and meeting our customers' expectations. These strategies help to bolster the
Port's Century Agenda strategy to advance the region as a leading tourism destination and
business gateway.
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1)  Replace the existing stepped timber seawall with a steel sheet pile wall. While
this option provides a long life, it is considerably more expensive and would present significant
access issues for placement of the pile under cantilevered sections of the pier and tying into each
end of the existing seawall. This is not the recommended alternative. 
Alternative 2)  Encase the existing seawall under a layer of riprap and gravel. While this
alternative provides a long life at lower cost, the current slope of the seawall would not allow for
this installation at an acceptable slope without impacting the existing floats. The required slopes
for this alternative would make the floats ground at extreme low tides without modification of
the existing float layout. This is not the recommended alternative.
Alternative 3)  Rebuild the existing seawall using long-life materials. This option offers a
balance of cost effectiveness and long life, along with easy site accessibility. It allows the wall
to maintain its existing geometry while strengthening it and extending its life.
This is the recommended alternative. 
ATTACHMENTS TO THIS REQUEST 
Existing condition and aerial view site photographs. 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
None.