Template revised January 10, 2019.
COMMISSION
AGENDA MEMORANDUM
Item No. 8c
ACTION ITEM Date of Meeting October 28, 2025
DATE: October 17, 2025
TO: Stephen P. Metruck, Executive Director
FROM: Eileen Francisco, Director Aviation Project Management
Keri Stephens, Director, Aviation Facilities and Capital Programs
SUBJECT: Snow Storage Expansion Phase II Construction Authorization
Amount of this request: $14,403,000
Total estimated project cost:
$24,800,000
ACTION REQUESTED
Request Commission authorization for the Executive Director to advertise and execute a
construction contract for Snow Storage Expansion Phase II (C801171) adjacent to the Industrial
Wastewater System (IWS) Lagoon 3.
The amount of this authorization request is $14,403,000 with the total project value at
$24,800,000.
EXECUTIVE SUMMARY
The Snow Storage Expansion project expands the laydown area available for stockpiling and
managing snow on the airfield during winter storm events to meet the operational and FAA
certification needs. The Lagoon 3 snow storage site, in conjunction with the constructed North
and South snow storage sites, will provide snow storage capacity for a 12” precipitation event on
the airfield ramp. Snowmelt runoff containing aircraft deicers will be routed to the Port’s IWS for
treatment meeting regulatory requirements.
JUSTIFICATION
The Lagoon 3 Snow Storage Site constitutes the final and essential phase of the broader Snow
Storage Expansion Project, which is a key infrastructure initiative aimed at enhancing the
airport’s ability to manage winter weather impacts. This site has been specifically designed to
accommodate the accumulation and controlled handling of snow volumes generated by a 12-
inch precipitation event across the airfield ramp, a critical operational area for aircraft movement
and ground handling activities.
COMMISSION AGENDA – Action Item No. 8c Page 2 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
By providing dedicated snow storage capacity in this location, the project significantly
strengthens the airport’s overall winter operations resilience. It minimizes the risk of weather-
related operational disruptions, particularly those affecting airline schedules and ramp logistics,
and supports continuous airfield availability during major snow events. The infrastructure is
engineered to collect and channel meltwater along with any associated deicing chemicals into
the Port’s IWS, thereby ensuring full compliance with the Port’s National Pollutant Discharge
Elimination Systems (NPDES) permit requirements and advancing the airport’s environmental
stewardship objectives.
The completion of Lagoon 3 not only fulfills regulatory and operational needs but also delivers
measurable benefits in terms of public safety, environmental protection, and service reliability.
Diversity in Contracting
The project staff, in coordination with the Diversity in Contracting Department, have set goals for
this contract. This contract is not federally funded and as such will include a 12% Woman and
Minority Business Enterprise (WMBE) aspirational goal.
DETAILS
This contract will involve limited interface with other projects and airline operations. Continual
coordination, where required, with Airport Operations, Airlines, and related Tenants will ensure
the least possible operational impact during construction.
Scope of Work
This scope of work in Phase II covers the development of the Lagoon 3 Snow Storage Site, which
will supplement the North and South Snow Storage Sites constructed in Phase I.
Site Grading and Laydown Area Expansion:
Earthwork and grading will be performed to create a stable, appropriately sized laydown area
suitable for the stockpiling, handling, and controlled melting of collected snow. The design will
ensure drainage compatibility and structural resilience for continuous snow management
operations.
Meltwater Collection and Conveyance System:
The site will be equipped with infrastructure to collect meltwater and associated deicing
chemicals and direct these flows to the existing Port IWS. This system will be designed to comply
with NPDES permit requirements for water quality and discharge standards.
Access Improvements – Vehicle Service Road, Gate, and Perimeter Fence:
Modifications will be made to the existing vehicle service road at the site entrance to achieve
appropriate roadway geometry and surface grading. The perimeter gate and fencing will be
COMMISSION AGENDA – Action Item No. 8c Page 3 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
widened and upgraded to accommodate large snow handling equipment, ensuring safe and
efficient site access under winter operational conditions.
Perimeter Intrusion Detection System (PIDS) Modifications:
Existing PIDS infrastructure located near the modified gate area will be adjusted to maintain the
integrity of the airport’s perimeter security system. All adjustments will be coordinated to ensure
no disruption to current security monitoring capabilities.
Site Lighting Installation:
New lighting fixtures will be installed at strategic locations to support safe nighttime and low-
visibility snow management activities. The lighting design will comply with airport standards
minimizing glare and light spill.
Schedule
Activity
Commission construction authorization 2025 Quarter 4
Construction start 2026 Quarter 2
In-use date 2026 Quarter 4
Cost Breakdown This Request
Total Project
Design $0
$2,500,000
Construction $14,403,000
$22,300,000
Total $14,403,000
$24,800,000
ALTERNATIVES AND IMPLICATIONS CONSIDERED
As part of the planning and environmental review process for the Snow Storage Expansion
Project, the Port conducted a comprehensive alternatives analysis to evaluate a range of viable
options for managing snow accumulation on the airfield during major winter storm events. This
evaluation considered technical feasibility, regulatory compliance, operational efficiency,
environmental impacts, and life-cycle costs.
Alternative 1 – Status Quo
Status quo was considered as a baseline scenario. While this alternative would avoid capital
expenditures and reduce infrastructure near sensitive wetland buffer areas, it presents
COMMISSION AGENDA – Action Item No. 8c Page 4 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
significant risks, including potential violations of the Port’s NPDES permit during heavy snow
events if sufficient designated storage areas are not available.
Cost Implications: $0
Pros:
(1) The avoidance of capital expenditures, resulting in immediate cost savings for the Port.
(2) By not constructing new infrastructure, this option minimizes disturbance to areas
adjacent to existing wetlands and reduces potential impacts to sensitive wetland buffer
zones.
Cons:
(1) Potential NPDES permit violation if snow is stored outside of a snow storage site during
heavy snow. NPDES violations could result in immediate fines, costly remediation
mandates, long-term operational burden, and strategic risks to capital programs and
grant funding.
This is not the recommended alternative.
Alternative 2 – Snow Melters with Snow Storage Pad
This alternative involves a capital investment of approximately $26,261,000 for the procurement
and installation of snow melting equipment and associated infrastructure, along with ongoing
operating expenses, including fuel, maintenance, staffing, and transportation logistics. While the
initial capital outlay may appear comparable to the snow storage site alternative, the recurring
operational costs over the system’s life cycle contribute to a higher total cost of ownership.
Cost Implications: Capital cost of 26,261,000 & annual expense cost
Pros:
(1) Avoidance of full infrastructure build-out if snow events are infrequent: One potential
benefit of deploying snow melters is that the equipment could remain idle in years with
lower-than-average snowfall, thereby delaying or avoiding some operational expenses.
In such years, the overall expenditure could be lower than for a dedicated snow storage
facility that requires ongoing maintenance regardless of snowfall volume.
(2) Operational flexibility and potential rapid snow removal: Snow melters provide a
mechanical means of quickly reducing snow volumes without requiring extensive land
area for storage. In certain scenarios, this method may expedite snow disposal
compared to traditional haul-and-dump operations, particularly when space is
constrained.
COMMISSION AGENDA – Action Item No. 8c Page 5 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
Cons:
(1) High fuel consumption and long-term operational burden: Snow melters require
significant fuel inputs to operate, particularly under heavy load conditions. This leads to
substantial greenhouse gas emissions, increased dependency on fuel supply chains, and
elevated operating costs. Infrequent use can further degrade equipment life
expectancy, resulting in more frequent replacement cycles and higher long-term capital
reinvestment needs.
(2) Infrastructure and site constraints limit feasibility: Port lacks the necessary ramp-side
infrastructure and spatial layout to support the effective use of snow melters on or near
the airfield. There is insufficient room for the staging, maneuvering, and operation of
these units in high-traffic aircraft movement areas. Consequently, snow would still need
to be trucked—sometimes long distances—off the ramp to a melting location such as
Lagoon 3, thereby negating much of the time and labor savings typically associated with
this equipment. This added complexity undermines operational efficiency and adds
further logistical burden.
This is not the recommended alternative.
Alternative 3 – Lagoon 3 Snow Storage
This alternative represents the currently planned approach and carries a total Capital
Improvement Program (CIP) cost of $23,800,000, which includes design, permitting, construction
of the Lagoon 3 snow storage site, and integration with the previously constructed North and
South sites. While this represents a substantial capital investment, the cost is aligned with the
scale of infrastructure needed to meet regulatory and operational demands for airfield snow
management.
Cost Implications: Total CIP cost of $24,800,000
Pros:
(1) Ensures NPDES regulatory compliance during major snow events: This alternative
provides dedicated infrastructure to collect and manage snow and meltwater in a
controlled environment, ensuring that runoff containing deicing agents and other
pollutants is properly routed to the Port’s IWS. This design is purpose-built to maintain
full compliance with the Port’s NPDES permit, specifically for storm events of up to 12
inches of precipitation—a threshold based on historical snowfall data and operational
modeling.
(2) Improved operational efficiency, reliability, and resilience: Purpose-built snow storage
sites significantly improve airfield snow removal efficiency by offering strategically
located, high-capacity laydown areas that minimize travel distances for snow-hauling
equipment. This reduces turnaround time during active weather events, enhances ramp
safety, and improves airline and ground crew operating conditions. The infrastructure
also supports 24/7 operations with lighting and access improvements, enabling
consistent response during low-visibility or night-time conditions.
COMMISSION AGENDA – Action Item No. 8c Page 6 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
Cons:
(1) Capital costs.
This is the recommended alternative.
FINANCIAL IMPLICATIONS
Cost Estimate
/Authorization Summary Capital
Expense
Total
COST ESTIMATE
Original estimate $17,450,000
50,000
$17,500,000
Previous changes 7,300,000
0
7,300,000
AUTHORIZATION
Previous authorizations $10,347,000
$50,000
$10,397,000
Current request for authorization $14,403,000
0
$14,403,000
Total authorizations, including this request $24,750,000
$50,000
$24,800,000
Remaining amount to be authorized $0
$0
$0
Annual Budget Status and Source of Funds
This project, CIP 801171, was included in the 2025-2029 capital budget and plan of finance with
a budget of $24,750,000. The funding sources include the Airport Development Fund and
revenue bonds. This project received Majority-In-Interest (MII) approval from the airlines on
October 20, 2021.
Financial Analysis and Summary
Project cost for analysis $24,800,000
Business Unit (BU) Airfield Movement Area
Effect on business performance
(NOI after depreciation)
NOI after depreciation will increase due to inclusion of
capital (and operating) costs in airline rate base
IRR/NPV (if relevant) N/A
CPE Impact $0.08 in 2027
Future Revenues and Expenses (Total cost of ownership)
Aviation Maintenance does not anticipate any material increase in operating expenses as a result
of the added pavement surface.
ATTACHMENTS TO THIS REQUEST
(1) Presentation slides
COMMISSION AGENDA – Action Item No. 8c Page 7 of 7
Meeting Date: October 28, 2025
Template revised June 27, 2019 (Diversity in Contracting).
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS
October 25, 2022 – The Commission authorized the Executive Director to advertise a
construction contract, and include a project labor agreement, for Snow Storage Expansion
project Phase 1 at Seattle-Tacoma International Airport (SEA) for a Total Request Amount
of $6,900,000 and a total project authorization of $10,347,000, and the Estimated Overall
Project Cost of $17,500,000.
October 26, 2021 – The commission authorized the Executive Director to design and prepare
construction documents for the Snow Storage Expansion project at Seattle-Tacoma
International Airport (SEA) for a Total Request Amount of $2,500,000 and a Total Project
Authorization of $2,794,000, and the Estimated Overall Project Cost of $17,500,000.
