Template revised April 12, 2018.
COMMISSION
AGENDA MEMORANDUM
Item No.
6c
ACTION ITEM
Date of Meeting
January 22, 2019
DATE: January 14, 2019
TO: Stephen P. Metruck, Executive Director
FROM: Wayne Grotheer, Director, Aviation Project Management Group
SUBJECT: Emergency Backup Water Supply (CIP #C800493)
Amount of this request:
$2,614,000
Total estimated project cost:
$2,739,000
ACTION REQUESTED
Request Commission authorization for the Executive Director to (1) prepare design and
construction bid documents for the Emergency Backup Water Supply project at Seattle-Tacoma
International Airport; (2) advertise and award a major works construction contract; and (3) use
Port of Seattle crews and small works contracts to perform construction work if required. The
amount of this request is $2,614,000. The total estimated project cost is $2,739,000.
EXECUTIVE SUMMARY
This project will develop the Tyee Golf Course well into an emergency backup water supply for
potable use and fire protection utilizing the Port’s existing water distribution system. The Sea-
Tac Airport Water System has no backup water supply as called for by the State Department of
Health (DOH) for potable use and fire protection.
The Seattle-Tacoma International Airport is currently supplied with domestic and fire protection
water by Seattle Public Utilities (SPU) via a single source. The Airport owns and operates a two
million gallon reservoir that can provide water for domestic use for up to three days, but if a
water outage from SPU is extended beyond two to three days, airport operations would be
critically impacted.
The scope of this project will replace the existing well building with a new water treatment
facility at the same location to handle up to 350 gallons per minute of instantaneous water
flow. This facility will utilize the existing wellhead (well and pump), a manganese filtration
system, a chlorination system, a clear well, and a booster pump system. Water produced by the
treatment facility will be transmitted to the existing water distribution system. The addition of
this needed treatment system, not contemplated in the original cost estimate, adds $2,239,000
to the project budget of $500,000 that is included in the 2019-2023 capital budget.
COMMISSION AGENDA – Action Item No. __6c__ Page 2 of 5
Meeting Date: January 22, 2019
Template revised September 22, 2016; format updates October 19, 2016.
JUSTIFICATION
Currently, all of the domestic and fire water needs for Airport are met by purchasing water
from SPU. In the event of disaster, water to the airport could be curtailed or shut off altogether.
The Airport has no backup for potable and fire water other than the supply from SPU. Backup is
available for almost all other utilities. The Airport has a two million gallon reservoir that can
provide domestic water supply for up to three days, but at the risk of using all the water
required for fire reserve. As a vital regional asset in the event of a disaster, it is important that
the Airport has adequate water supply to operate in case of emergency.
Our vulnerability was pointed out by DOH in a June 13, 2013, report. The DOH engineer
recommended that we should "…consider conducting an evaluation of the pros and cons
associated with developing (our) existing well(s) as an emergency supply option in the event of
loss or service from Seattle."
The project would upgrade the existing Tyee Golf Course well and pumping system to add
filtration, chlorination, an emergency generator, a new building, and piping as required to
augment the SeaTac Airport Water System. The facilities would be designed and constructed
primarily for emergency purposes. The necessary change of use water right has been obtained
for this well from the Washington State Department of Ecology. Once the system is installed
and approved by DOH, the well can be tested and activated as an emergency supply within
three days of an outage of the SPU system (about the time at which our reservoir would be
depleted). The amount of water available would be approximately half of the normal usage, but
still enough to supply priority uses and maintain critical operations.
DETAILS
This project will construct a water treatment facility at the existing Tyee Golf Course wellhead.
The existing Tyee Golf Course well building will be demolished. This new facility will provide an
emergency backup water supply for the airport water system and will be treated for
manganese to eliminate potential staining of plumbing fixtures. Treated water will be provided
to the existing Port distribution system via a new water main extension to the existing airport
piping system; filter backwash water will be disposed to the nearby sewer utility.
Scope of Work
The project will include the following work items:
(1) Demolition and removal of existing Well House and associated surface improvements;
(2) Construction of new well house, treatment system and pumping equipment;
(3) Construction of new improvements including sewer discharge, driveway, treatment
pad and instrumentation;
(4) Construction of new water transmission line with connection to existing Port
infrastructure.
COMMISSION AGENDA – Action Item No. __6c__ Page 3 of 5
Meeting Date: January 22, 2019
Template revised September 22, 2016; format updates October 19, 2016.
Schedule
Activity
Design start
Commission construction authorization
Construction start
In-use date
Cost Breakdown
This Request
Total Project
Design
$736,000
$861,000
Construction
$1,878,000
$1,878,000
Total
$2,614,000
$2,739,000
ALTERNATIVES AND IMPLICATIONS CONSIDERED
Alternative 1 – Do not proceed with the project.
Cost Implications: An estimated $75,000 in costs to date would need to be expensed if this
project is canceled.
Pros:
(1) Does not require capital investment.
(2) Does not involve any shutdown of current facilities.
Cons:
(1) This option will not reduce the risk involved with the lack of a backup water system for
the Airport.
(2) In the event of a regional incident which damages the current water supply infra-
structure provided by Seattle Public Utilities, the Airport would be without water for
an extended period of time, halting airport operations during a time of critical need.
This is not the recommended alternative.
Alternative 2 – Design and construction of a basic water supply system (without water
treatment) consisting of only the well, pump and transmission line.
Cost Implications: $500,000
Pros:
(1) Would provide nominal water backup capacity in the event of a disruption to the
existing SPU water source.
(2) Construction would involve very little disruption to the activity of the existing system.
(3) Very low on-going maintenance cost since no filters to clean or replace, and no
chlorine to keep on-site.
(4) Water Treatment Plant Operator (WTPO) certification not required to operate this
system.
COMMISSION AGENDA – Action Item No. __6c__ Page 4 of 5
Meeting Date: January 22, 2019
Template revised September 22, 2016; format updates October 19, 2016.
Cons:
(1) Upon operation the system would introduce manganese and other potentially harmful
substances into the Airport’s distribution system. Even low-levels of manganese (0.05
mg/L) will lead to staining of the water and those facilities in contact with the water.
This is not the recommended alternative.
Alternative 3 – Design and construction of a new water supply and treatment system consisting
of the well, pump, chlorination tank, manganese filter and transmission line.
Cost Implications: $2,739,000
Pros:
(1) Eliminates the risk involved with a solitary water supply to the airport.
(2) In the event of a regional incident which damages the current water supply
infrastructure provided by SPU, the Airport could continue to operate during a time of
critical need.
(3) Construction would not involve disruption to the existing system.
(4) Would not introduce manganese and other potentially harmful substances into the
Airport’s distribution system.
Cons:
(1) Requires WTPO certification to operate and maintain.
(2) Requires on-site storage of hazardous chemical (sodium hypochlorite which is the
active ingredient in household bleach).
This is the recommended alternative.
FINANCIAL IMPLICATIONS
Cost Estimate/Authorization Summary
Capital
Expense
Total
COST ESTIMATE
Original estimate
$500,000
$0
$500,000
Previous changes – net
0
0
0
Current change
$2,239,000
0
$2,239,000
Revised estimate
$2,739,000
0
$2,739,000
AUTHORIZATION
Previous authorizations
$125,000
0
$125,000
Current request for authorization
$2,614,000
0
$2,614,000
Total authorizations, including this request
$2,739,000
0
$2,739,000
Remaining amount to be authorized
$0
$0
$0
COMMISSION AGENDA – Action Item No. __6c__ Page 5 of 5
Meeting Date: January 22, 2019
Template revised September 22, 2016; format updates October 19, 2016.
Annual Budget Status and Source of Funds
This project (CIP #C800493) was included in the 2019 – 2023 capital budget and plan of finance
as a business plan prospective project with a total budget of $500,000. The budget increase is
due to the need to scope for a water treatment system. The increase of $2,239,000 was
transferred from the Aeronautical Allowance C800753, resulting in no net change to the
Aviation capital budget. The funding source for this project will be the Airport Development
Fund and future revenue bonds.
Financial Analysis and Summary
Project cost for analysis
$2,739,000
Business Unit (BU)
Terminal Building
Effect on business performance
(NOI after depreciation)
NOI after depreciation will increase
IRR/NPV (if relevant)
N/A
CPE Impact
$0.01 in 2022
Future Revenues and Expenses (Total cost of ownership)
This water production system is not expected to significantly increase future maintenance
costs.
ATTACHMENTS TO THIS REQUEST
(1) Presentation slides
(2) June 18, 2013 letter from the DOH
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS
None