PORT OF SEATTLE 
MEMORANDUM 
COMMISSION AGENDA    Item No.   5a
Date of Meeting    June 1, 2010
DATE:   May 24, 2010
TO:     Tay Yoshitani, Chief Executive Officer
FROM:   Ralph Graves, Managing Director, Capital Development Division
SUBJECT: Delay Stormwater Retention Pond M Construction, a Portion of the 2010 Airfield
Improvement Projects  Contract 2. CIP # C100172
AMOUNT OF THIS REQUEST: $ 0             SOURCE OF FUNDS: N/A
ACTION REQUESTED:
Request authorization to separate Stormwater Retention Pond M from the other 2010 Airfield
Improvement Projects  Contract 2 (AIP-2) and delay construction until 2011.
SYNOPSIS:
This authorization will allow a one-year delay to the construction of Stormwater Retention Pond
M at Seattle-Tacoma International Airport and provides for a change in the scope of work which
must be approved by the commission in accordance of section 4.2.3.3."ii" of Resolution No.
3605
Pond M, one of the remaining Third Runway Projects, was authorized by Commission on
January 12, 2010, for construction bid advertisement as part of the Airfield Improvement
Project-2 (AIP-2). Unforeseen site conditions, particularly unsuitable foundation soils, were
discovered post authorization by field soil investigations. These conditions necessitate further
design and analysis time to fully evaluate, design, permit, and construct this permanent
stormwater facility. Local agencies have been notified and agree with the delay of Pond M until
2011.
There may be additional costs associated with the delay of this work in the form of contractor
mobilization and additional project/construction management expenses resulting from a second
contract. Port Staff will continue to review options for combining the delayed work with other
work in 2011 to mitigate the potential for additional costs.
No additional project funds are being requested as part of this authorization. The original budget
for AIP-2, per the January 12, 2010, authorization was $6,625,000. The estimated value of work
delayed as part of this request is $3,500,000. Additional costs associated with a second contract
will be covered by previously authorized Third Runway Program contingency. Staff will return
to Commission in late 2010 to provide an update on the delayed work and request authorization
to advertise for construction bids.

COMMISSION AGENDA 
T. Yoshitani, Chief Executive Officer
May 13, 2010
Page 2 of 3

BACKGROUND:
The AIP-2 includes several projects that must be accomplished to fulfill Third Runway Permit
obligations and complete compensatory mitigation associated with the Miller Creek Relocation.
The overall project includes:
The removal of the 160th Street Box Culvert as compensation for the inability of the
Miller Creek Relocation Channel to meet minimum velocity requirements
Placement of additional gravel in the relocation channel to improve stream flow
characteristics and water quality
Installation of pond liners to eliminate vegetation growth inside four Third Runway
permanent stormwater ponds
Construction of a permanent stormwater outfall piping system from Pond D to Miller
Creek
Conversion and modification of Pond M and stormwater vault SDS 6/7 from construction
stormwater facilities to permanent stormwater detention facilities. (Delayed until 2011)
On January 12, 2010, the Port Commission authorized advertisement for construction bids of the
AIP-2. At the time of authorization, the design team was in process of completing the final
design for the project. One of the final design components was a requirement to obtain a
Washington State Department of Ecology Dam Safety Permit for the Pond M facility due to
overall volume of stormwater planned to be detained. A portion of the permit process included a
geotechnical and hydraulic engineering analysis to determine the structural stability of the Pond
M earthen embankment dam. During the course of this analysis and site soil investigations, it
was determined the Pond M site was underlain by loose, organic, and otherwise geotechnically
poor soils. The presence of these types of soils necessitates further design and analysis prior to
construction of the Pond M facility.
Due to the increased design and analysis period required for Pond M, the design team is
recommending delaying the Pond M component of the 2010 project until the 2011 construction
season. The type of work and the proximity to adjacent wetlands, necessitates the construction
be completed in the relatively dry summer season. There is simply not enough time remaining in
the 2010 schedule to complete the design, permitting, and construction within the desired
weather window. The other remaining components of the project, however, would continue on
schedule and be completed in 2010.
Pond M is one of a series of stormwater ponds needed to retrofit the entire Airport to current
standards as required by environmental permits. The ponds were to be constructed and
operational before opening the Third Runway. Staff requested and was granted an extension for
the Pond M construction until the Fall of 2010 due to conflicts between the pond site and the 16L
reconstruction project. The agencies have again been notified that the project will be further

COMMISSION AGENDA 
T. Yoshitani, Chief Executive Officer
May 13, 2010
Page 3 of 3

delayed due to the unforeseen technical difficulties mentioned above. Permittees who willfully
violate project permits are in extreme cases subject to monetary penalty and imprisonment.
However, as noted above, staff is working directly with the Washington State Department of
Ecology's Dam Safety office to finalize the design and are committed to constructing the Pond in
2011.
The original budget for AIP-2, per the January 12, 2010, authorization was $6,625,000. The
estimated value of work delayed as part of this request is $3,500,000.
As required by Resolution No. 3605, section 4.2.3.3(ii), additional Commission authorization is
required if project changes or delays will have material, financial, community or business
impacts. The Pond M construction delay is a material change to this project. Staff will return to
Commission in early 2011 to provide an update on the project and request authorization for
advertisement of construction bids for the Pond M work.
PROJECT SCHEDULE
2010 Airfield Improvement Projects  Contract 2
Start Construction:    July 2010
Project Completion Date: December 2010 
2011 Pond M Project
Complete Design:    4th Quarter 2010
Start Construction:    2nd Quarter 2011
In-use Date:        4th Quarter 2011
Project Completion Date: 4th Quarter 2011 
CONSEQUENCES OF NOT PROCEEDING: 
Port staff has notified environmental permitting agencies that Pond M completion will not occur
this year. Not proceeding with the project in 2011 will place the Port in violation of the
Airport's NPDES permit as well as the 401 Water Quality Certification and 404 Permit for the
Third Runway and other Master Plan Update Improvement Projects.
FINANCIAL IMPLICATIONS: 
The budget to pay for the Pond M construction delay is part of the Third Runway Program
contingency budget previously authorized by the Port Commission. No additional project budget
is being requested as a result of this change.