COMMISSION 
AGENDA MEMORANDUM                        Item No.          6g 
ACTION ITEM                            Date of Meeting      August 11, 2020 
DATE:     June 2, 2020 
TO:        Stephen P. Metruck, Executive Director 
FROM:    Elizabeth Leavitt, Senior Director, Environment and Sustainability 
Arlyn Purcell, Director, Aviation Environment and Sustainability 
SUBJECT:  Miller Creek Culvert Replacement, Fish Passage and Stream Restoration  (CIP #
C801156) 
Amount of this request:                 $800,000 
ACTION REQUESTED 
Request Commission authorization for the Executive Director  to execute an Interlocal
Agreement (ILA) with the City of Burien (City) specifying the Port will contribute $800,000
toward the City's project to divert Miller Creek and municipal stormwater from a culvert
underneath a private storage facility, abandon a failing stream culvert under Des Moines
Memorial Boulevard, and construct fish-passable culverts along 450 linear feet of newly
restored stream habitat on Port property. 
This project will redress existing and anticipated future impacts to Port mitigation sites as well
as improve municipal road and stormwater infrastructure.  Construction costs for the project
total $3.5 million.  The City experienced a funding shortfall and requested the Port contribute
$0.8M toward construction. The Port's contribution is a cost-effective investment to protect its
mitigation area from any impacts of future culvert failures. 

EXECUTIVE SUMMARY 
The City plans to divert Miller Creek and municipal stormwater from a culvert underneath a
private  storage  facility,  abandon  a  failing  stream  culvert  under  Des  Moines  Memorial
Boulevard, and construct fish-passable culverts along 450 linear feet of newly restored stream
habitat on Port property. The project will protect existing Port mitigation sites and ensure
continued compliance with authorizing Clean Water Act permits. While the purpose for the
action is to minimize the Port's compliance costs, the projectas a whole will also result in 
significant ecological benefits. 


Template revised January 10, 2019.

COMMISSION AGENDA  Action Item No. 6g                                   Page 2 of 6 
Meeting Date: August 11, 2020 
At the November 19, 2019, public meeting, the Commission adopted Motion 2019-14 directing
staff to negotiate a new ILA to contribute funds to ensure the Project is constructed. The ILA (1)
authorizes the Port's funding contribution, (2) sets out a division of labor for post-construction
tasks, and (3) protects the Port's interests and liability for the proposed project. Under the ILA,
the Port would contribute the amount of $800,000 toward the $3.5M project cost and the City
would carry out the work and coordinate with all necessary stakeholders. 
JUSTIFICATION 
This project will redress existing and anticipated future impacts to Port mitigation sites as well
as improve municipal road and stormwater infrastructure. Construction costs for the project
total $3.5 million. The City experienced a funding shortfall and requested the Port contribute
$0.8M toward construction. The Port's contribution is a cost-effective investment to protect its
mitigation area from any impacts of future culvert failures. 
Immediately upstream of the mitigation site are two culverts: one that drains approximately
1,500 acres of stream and stormwater flow under Des Moines Memorial Boulevard, and
another culvert privately-owned by the Des Moines Way Storage Facility,  which conveys
stormwater flow from the City's culvert plus stormwater from the 3.5 acres of storage facility 
property into Miller Creek within the boundaries of the Port's mitigation site.
The project scope includes replacing the culvert under Des Moines Memorial Boulevard that is
at risk of failure and poses a danger to public safety. The City has proposed to address both
culverts by restoring a natural stream channel ("the Miller Creek Project") for thestream and
stormwater flow through the City's culvert under Des Moines Memorial Boulevard. 
The failing culvert under the privately-owned Des Moines Way Storage Facility discharges
directly into a stream and wetland mitigation site northwest of Sea-Tac International Airport
(Airport) that the Port is required to maintain as a condition of the Airport's Third Runway
permits (Clean Water Action Section 401/404 Permit #1996-04-02325 (Amended-2)).  The
culvert failed in 2017, discharging a large quantity of sediment to the Port mitigation site that
impaired its function. The existing culvert is likely to fail again in the future and risk permit
noncompliance unless a permanent fix is undertaken. The storage facility culvert will remain in
place, but we have confirmed with an engineer that the project will eliminate 97% of the water
currently flowing through the storage facility culvert from the Des Moines Memorial Boulevard
culvert.  This will prevent future failures of the storage facility culvert  and eliminate the
possibility of similar discharges to the Port's mitigation site. 
Contributing the requested funds is the most cost-effective way to ensure the Port's mitigation
sites are protected and address the City's infrastructure needs. 


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

COMMISSION AGENDA  Action Item No. 6g                                   Page 3 of 6 
Meeting Date: August 11, 2020 
DETAILS 
Planning, design, and environmental review for the Project were authorized and have been
completed pursuant to existing Port-Burien ILAs related to Northeast Redevelopment Area
(NERA) planning and development. Commission authorized an ILA in 2013, enabling a master
drainage plan and shared use path components, of which are located on Port property inside
the Project footprint.
This project will take place on  city right-of-way and Port property containing mitigation
covenant areas, a common use trail, and vacant land. The property also contains stormwater
infrastructure for the NERA, a 160-acre area jointly planned by the Port and the City for
redevelopment with airport dependent land use. The 2018 ILA approved by the Commission, 
authorized the City to construct the stream restoration to the west of Des Moines Memorial
Boulevard. This ILA is necessary to convey the remaining easements required for construction
on the east of Des Moines Memorial Boulevard. Therefore, the project is construction-ready,
and the City plans to construct the project between July and October 2021. At the
November 19, 2019, public meeting, Commission adopted Motion 2019-14 directing staff to
negotiate a new ILA to contribute funds to ensure the Project is constructed. 
While the purpose for the action is to minimize the Port's compliance costs, the project as a
whole will also result in significant ecological benefits. The project is a key component of the
overall restoration of the Miller Creek watershed and thus includes significant community and
environmental benefits. It removes the largest fish barrier on the creek and links the City's
NERA stream, wetland and riparian restoration projects located directly upstream with the
Port's two miles of stream mitigation, includingin the project area. The Port has already
removed two fish passage barriers (2012) and plans to remove another passage barrier in the
north Runway Safety Area in 2022. WSDOT is also removing a fish barrier downstream of Port
mitigation under Des Moines Memorial Boulevard. These actions provide a comprehensive
approach to watershed management and create a contiguous stream and riparian corridor with
passable road crossings. 
Schedule 
The City plans to complete all construction in spring and summer (approximately April  
October, 2021). 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1  Port repairs the culvert under the storage facility as a stand-alone project. 
Cost Implications: $839,000 construction cost plus legal, planning, permitting, design, and
project management costs. 
Pros: 
(1)   Protects Port mitigation sites from future impacts that could either require the Port to
restore the site and/or trigger an enforcement action by the Army Corps of Engineers. 

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

COMMISSION AGENDA  Action Item No. 6g                                   Page 4 of 6 
Meeting Date: August 11, 2020 
(2)   Maintains  good-faith  standing  with  permitting  agencies,  including  its  ability  to
negotiate favorable terms and conditions for future permits. 
Cons: 
(1)   Estimated  construction  costs  alone  equal  $839,000.  However,  if  the  Port  were
required to repair the failing culvert under the storage facility in the event of another
failure, the need for a new planning, design and permitting process  as well as 
associated negotiations for access would likely result in a higher cost. 
(2)   No party has been willing to claim ownership of the failing culvert under the storage
facility.  Accessing the storage facility property to repair the culvert would require
extensive legal negotiations and impact the private business's operation, which would
also significantly increase costs. 
(3)   The Port has coordinated planning, design, permitting and funding with the City of
Burien. Failing to follow-through when the project is ready for construction does not
demonstrate good faith and partnership with Burien. 
(4)   Does not implement Commission Motion 2019-14 directing staff to negotiate an ILA
with Burien to fund the stream restoration project. 
This is not the recommended alternative. 
Alternative 2  Port does not contribute funding to the Burien project, in which case the City
will  limit  its  project  scope  to  repairing  the  existing  culvert  under  Des  Moines  Memorial
Boulevard. 
Cost  Implications:  Zero  short-term  costs,  but  long-term  costs  would  equal  $839,000
construction cost plus legal, planning, permitting, design, and project management costs 
Pros: 
(1)   Reduces short-term costs to zero. 
Cons: 
(1)   A future release from the failing culvert under the Des Moines Storage Facility into the
Port's mitigation site could put the mitigation site out of compliance with Clean Water
Act permit conditions and prompt an enforcement action by the Corps. Such an action
would require the Port to address impacts from the failing culvert in the same manner
as Alternative 1. In addition to any immediate mitigation measures to address damage
to the wetland from a failure, the regulatory agencies would require the Port to 
undertake a long-term solution which would result in the same project and costs
summarized in Alternative 1. Thus, this alternative will be more expensive than both
Alternative 1 and the Port's proposed $839,000 contribution (Alternative 3, below). 
(2)   The Port has completed negotiations with regulatory agencies administering the
existing mitigation permits as well as the new Clean Water Act permit authorizing the
Project. Failing to follow-through when the project is ready for construction would
reduce the Port's standing with permitting agencies, including potentially its ability to
negotiate favorable terms and conditions for future permits. 

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

COMMISSION AGENDA  Action Item No. 6g                                   Page 5 of 6 
Meeting Date: August 11, 2020 
(3)   The Port has coordinated planning, design, permitting and funding with the City of
Burien. Failing to follow through when the project is ready for construction does not
demonstrate good faith and partnership with Burien. 
(4)   Does not implement Commission Motion 2019-14 directing staff to negotiate an ILA
with Burien to fund the restoration project. 
This is not the recommended alternative. 
Alternative 3  Contribute funding to the City's project to divert Miller Creek and municipal
stormwater from a culvert underneath a private storage facility, abandon a failing stream
culvert under Des Moines Memorial Boulevard, and construct fish-passable culverts along 450
linear feet of newly restored stream habitat on Port property. The project is a cost-effective
way to protect the Port's mitigation site. 
Cost Implications: $800,000 
Pros: 
(1)   Protects Port mitigation sites from future impacts that could either require the Port to
restore the site and/or trigger an enforcement action by the Army Corps of Engineers. 
(2)   Least expensive option. 
(3)   Realizes cost efficiencies from a single, joint planning and design effort with Burien. 
(4)   Builds on a partnership with the Airport's local government partners. 
(5)   Maintains  good-faith  standing  with  permitting  agencies, potentially improving  its
ability to negotiate favorable terms and conditions for future permits. 
(6)   Implements Commission Motion 2019-14 directing staff to negotiate an ILA with
Burien to fund the restoration project. 
Cons: 
(1)   Use of operating funds that could be applied elsewhere. 
This is the recommended alternative. 
FINANCIAL IMPLICATIONS 
Cost Estimate/Authorization Summary               Capital        Expense           Total 
COST ESTIMATE 
Estimated total project cost                       $3,500,000               $0      $3,500,000 
City of Burien share of costs                       $2,700,000                        $2,700,000 
Port share of costs                                   $800,000               $0        $800,000 
AUTHORIZATION 
Previous authorizations                                   $0               $0               $0 
Current request for authorization                  $800,000               $0        $800,000 
Total authorizations, including this request         $800,000               $0        $800,000 
Remaining amount to be authorized                    $0             $0             $0 

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

COMMISSION AGENDA  Action Item No. 6g                                   Page 6 of 6 
Meeting Date: August 11, 2020 
Annual Budget Status and Source of Funds 
This project, CIP C801156, was not included in the 2020-2024 capital budget and plan of
finance. A budget of $800,000.00 was transferred from the Aeronautical Reserve CIP (C800753)
resulting in zero net change to the Aviation capital budget. The funding source will be the
Airport Development Fund (ADF). 
Financial Analysis and Summary 
Project cost for analysis              $800,000 
Business Unit (BU)                  Airfield Movement Area 
Effect on business performance     NOI after depreciation will increase due to inclusion of
(NOI after depreciation)             capital (and operating) costs in airline rate base. 
IRR/NPV (if relevant)                N/A 
CPE Impact                       Less than $.01 in 2021 
Future Revenues and Expenses (Total cost of ownership) 
The Port will incur costs for performance monitoring inside existing mitigation covenant areas
and routine maintenance over the long-term. 
ATTACHMENTS TO THIS REQUEST 
(1)   Project concept 
(2)   Presentation slides 
(3)   Draft Port-City of Burien Interlocal Agreement 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
November 11, 2019  The Commission passed a Motion to advance Miller Creek Restoration
and Noise Monitor Purchase and Installation 
May 8, 2018  The Commission authorized an Interlocal Agreement ("ILA") between the
Port of Seattle and the City of Burien for the on-going redevelopment of the Northeast
Development Area ("NERA") properties. 






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