COMMISSION
AGENDA MEMORANDUM

Item No.

ACTION ITEM

Date of Meeting

DATE :

February 4, 2025

TO:

Stephen P. Metruck, Executive Director

FROM:

Keri Stephens, Director, AV Facilities & Capital Programs
Eileen Francisco, Director, Aviation Project Management Group

8h
February 11, 2025

SUBJECT: 1947 Water Main Improvements Project Authorization (CIP #C801224)
Amount of this request:
Total estimated project cost:

$12,200,000
$13,300,000

ACTION REQUESTED
Request Commission authorization for the Executive Director to (1) transfer authorization and
up to $3,200,000 of budget from the C801042 Landside Pavement Program to support
additional pavement rehabilitation, and (2) take all steps necessary to complete the 1947
Water Main Improvements project located at Seattle-Tacoma International Airport (SEA). The
amount requested for authorization is $12,200,000 for a total project authorization of
$13,300,000.
EXECUTIVE SUMMARY
The 1947 Watermain Improvement project's goal is to mitigate the risk of future critical failures
of the existing 1947 water main. The Utility Master Plan (UMP) identified sections that are
deficient or nearing the end of its serviceable lifespan that includes this section of the water
main. The section of the water main has experienced multiple failures requiring emergency
repairs, most recently in January 2021. The project will abandon the existing water main and
replace it with a new water main in a new alignment. Additionally, the project is rehabilitating
the pavement at the south terminal bus stops and S 182nd St entrance/exit roadways, and
completing the structural rehabilitation, primarily the failed expansion joints, of Bridge 2 which
is the exit ramp from Arrivals to the Northern Airport Expressway.
JUSTIFICATION
This project will support the Century Agenda goal to advance this region as a leading tourism
destination and business gateway by meeting the region's air transportation needs through

Template revised January 10, 2019.

COMMISSION AGENDA - Action Item No. 8h
Meeting Date: February 11, 2025

Page 2 of 5

improving vital facilities and infrastructure in a sustainable and cost-effective manner. The
water main and bridge expansion joints have reached the end of their serviceable life and
require replacement or rehabilitation.
Diversity in Contracting
The design of this project will utilize an existing Indefinite Delivery / Indefinite Quantity (IDIQ)
Contract to provide design services. The contract has a 10% over-all Women Minority Owned
Business Enterprise (WMBE) participation goal. As this project has federal funding, the project
team will work with Diversity in Contracting department and the Washington State Department
of Transportation (WSDOT) to establish additional Disadvantaged Business Enterprise (DBE)
goals for the construction contract.
DETAILS
This section of the water main was constructed circa 1947 and provides domestic water to the
Cooling Towers, Main Garage (including the North Toll Plaza), and Sound Transit light rail
station at SEA. This section of water main also provides the required flow for fire suppression
in the Delta and Alaska Airlines aircraft hangars.
The project originally proposed to rehabilitate the existing water main by using a cured-in-place
pipe (CIPP) liner within the host pipe. This approach was thought to be less costly than full
replacement and would significantly extend the useful life of the water main. However, as the
preliminary design effort progressed the costs for CIPP continued to increase and soon were at
the level of full pipe replacement. Costs increased due to 1) the cost of a more specialized pipe
liner due to the high operating pressure, and 2) the number and location of required access pits
and associated traffic control and asbestos abatement. Port staff explored a full pipe
replacement option and determined that this option represented a better overall investment
for the Port.
The project will replace the water main from south of the S 182nd St intersection with
International Blvd along a new alignment ending north of the light rail pedestrian bridge. The
entire length of watermain replaced will be approximately 2,400 linear feet. Additionally,
improvements to Bridge 2 and the terminal South Bus Stops were included since those
improvements are in the same work area.
Scope of Work
The water main rehabilitation scope is changed to conventional pipe replacement instead of
cured-in-place-pipe (CIPP) and additional scope is added to the project:
(1) Conventional Pipe Replacement will provide more reliable water main infrastructure
at a lower cost with more manageable construction impacts than the original scope.
(2) Bridge 2: Rehabilitate two expansion joints on Bridge 2 as well as complete minor
structural and stormwater improvements addressing hazardous failed infrastructure.

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA - Action Item No. 8h
Meeting Date: February 11, 2025
(3)

Page 3 of 5

South Bus Stops: Replace the pavement and curb lines at the terminal south bus stops
including the rental car busing operation, public transit, and airporters. This scope is
identified for a future project but will have reduced construction impacts when
combined with the 1947 Watermain project.

The existing project will also deliver a portion of the Landside Pavement Program (C801042)
since the pavement rehabilitation scope includes the S 182nd St entrance and exit roadways
that are located above the water main. This work is supported by a PSRC Pavement
Preservation grant funded by the Federal Highway Administration (FHWA) and administered by
WSDOT.
Schedule
Activity
Construction start
In-use date

2025 Quarter 4
2026 Quarter 4

Cost Breakdown

This Request

Total Project

Design
Construction
Total

$1,200,000
$11,000,000
$12,200,000

$2,300,000
$11,000,000
$13,300,000

ALTERNATIVES AND IMPLICATIONS CONSIDERED
Alternative 1 - Restore the existing water main pipe by CIPP lining only
Cost Implications: $10,200,000
Pros:
(1)

Innovative repair method

Cons:
(1)
(2)
(3)
(4)

Major disruption to operations (lane closures, detours, roadway capacity reduction)
Significant capital investment for shorter service life
Requires more capital investment than initially budgeted
Adjacent deficient infrastructure remains at Bridge 2 and at terminal South Bus Stops.

This is not the recommended alternative.
Alternative 2 - Replace the water main pipe only
Cost Implications: $9,910,000
Pros:
(1)
(2)

Lower capital investment for longer service life
Manageable construction impacts

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA - Action Item No. 8h
Meeting Date: February 11, 2025
Cons:
(1)
(2)
(3)

Page 4 of 5

$120,000 of project costs will need to be expensed due to the project scope change
from CIPP to full replacement
Requires more capital investment than initially budgeted
Adjacent deficient infrastructure remains at Bridge 2 and at terminal South Bus Stops

This is not the recommended alternative.
Alternative 3 - Replace the water main pipe and rehabilitate Bridge 2 and the terminal South
Bus Stops
Cost Implications: $13,300,000
Pros:
(1)
(2)
(3)
Cons:
(1)
(2)

Lower capital investment for longer service life (for water main portion)
Manageable construction impacts
Cost savings and reduced construction impacts from bundling adjacent improvements
for deficient infrastructure at Bridge 2 and at terminal South Bus Stops
$120,000 of project costs will need to be expensed due to the project scope change
from CIPP to full replacement
Requires more capital investment than initially budgeted

This is the recommended alternative.
FINANCIAL IMPLICATIONS
Cost Estimate/Authorization Summary

Capital

Expense

Total

COST ESTIMATE
Original estimate
Previous changes - net
Current change
Revised estimate sub-total
Budget transfer from C801042 (if approved)
Revised estimate Total

$2,263,000
$2,056,000
$8,861,000
$13,180,000
$3,200,000
$16,380,000

$0
$0
$120,000
$120,000
$0
$120,000

$2,263,000
$2,056,000
$8,981,000
$13,300,000
$3,200,000
$16,500,000

AUTHORIZATION
Previous authorizations
Current request for authorization
Revised authorization sub-total
Authorization transfer C801042 (if approved)
Total authorizations, including this request
Remaining amount to be authorized

$1,100,000
$12,080,000
$13,180,000
$3,200,000
$16,380,000
$0

$0
$120,000
$120,000
$0
$120,000
$0

$1,100,000
$12,200,000
$13,300,000
$3,200,000
$16,500,000
$0

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA - Action Item No. 8h
Meeting Date: February 11, 2025

Page 5 of 5

Annual Budget Status and Source of Funds
This project (C801224) was included in the 2025-2029 capital budget and plan of finance with a
budget of $4,319,000. A budget of $8,861,000 was transferred from the Utility Master Plan
Allowance (C801267) resulting in a zero net change to the Aviation capital budget. A budget
transfer up to $3.2M will come from C801042 Landside Pavement Program. The funding
sources will be the Airport Development Fund (ADF) and revenue bonds.
Financial Analysis and Summary
Project cost for analysis
Business Unit (BU)
Effect on business performance
(NOI after depreciation)
IRR/NPV (if relevant)
CPE Impact

$16,500,000
Multiple cost centers with airlines cost recovery at 51%.
NOI after depreciation will increase due to inclusion of
capital (and operating) costs in airline rate base.
N/A
$.03 in 2027

Future Revenues and Expenses (Total cost of ownership)
The operations and maintenance costs are anticipated to be minimal.
ADDITIONAL BACKGROUND
The Utility Master Plan was completed at SEA and included four objectives: 1) investigate,
analyze, assess the existing condition and capacity, 2) analyze future infrastructure needs to
reliably meet demands of the Aviation capital program and proposed Sustainable Airport
Master Plan projects, 3) recommend and prioritize projects for inclusion in the Aviation capital
program, and 4) support SEA's sustainability goals with respect to water, energy, and emissions.
The overall utility infrastructure needs were categorized as either condition/capacity, project
driven, or vision. For the water utility system, that supports domestic water and fire
suppression, four projects were identified for immediate implementation to address condition
or capacity concerns. The 1947 Water Main Improvements project is one of those four
projects.
ATTACHMENT TO THIS REQUEST
(1) Presentation slides
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS
November 12, 2024 - The Commission authorized the Executive Director to take all steps
necessary to complete the Landside Pavement Program project (C801042) for a total
authorization of $9,320,000.
September 13, 2022 - The Commission authorized the Executive Director to complete
design of the 1947 Water Main Improvements project (C801224) for a total
authorization of $1,100,000.

Template revised June 27, 2019 (Diversity in Contracting).