HomeMy WebLinkAbout2025-08-25 - Request for Proposals - Nelsen Side Channel Salmon Habitat Project1
CITY OF TUKWILA REQUEST FOR PROPOSALS (RFP) Nelsen Side Channel Salmon Habitat Project Due August 25, 2025, by 5:00 p.m. Pacific Standard Time (PST) The City of Tukwila is soliciting Proposals from qualified consulting firms to provide
multidisciplinary engineering, design, and planning services for Phase I of the Nelsen
Side Channel Salmon Habitat Project (NSCSHP). The Nelsen Side Channel Project will create off-channel habitat for Chinook and other aquatic species and flood risk reduction in the tidally influenced section of the Green River at approximate River Mile 12.5, south of I-405 on the right bank. The project will include levee removal and setback as well as
public open space and river access. The project area is constrained by I-405 and Exit #1 off-ramp to the north and east and commercial development to the south. Please review the full RFP following this notice
Any questions regarding this RFP should be directed to Joshua Hopkins, Surface Water
Project Manager at Joshua.Hopkins@TukwilaWA.gov. Only email inquiries will be
accepted. Interested firms have three options to submit their proposal (e-mail, mail, or
hand-deliver). All formats should be addressed to Joshua Hopkins.
All submission formats should be received no later than 5:00 p.m. PST, August 25
2025. No submittal will be accepted after this date and time. Please reference the RFP
title on all communication.
E-mail: Joshua.Hopkins@TukwilaWA.gov
Mail: City of Tukwila Public Works Department 6300 Southcenter Boulevard, Suite 200 Tukwila, Washington 98188
Hand-deliver: Tukwila City Hall
6200 Southcenter Blvd
Tukwila, WA 98188 Hand-delivery accepted Monday through Thursday from 8:30 a.m. to 4:00 p.m. PST.
The entrance is near the flagpole. There is also a drop box at the entrance doors to City
Hall 24 hours a day, however, it may not be large enough to handle the proposals.
Please plan accordingly to meet the deadline.
Published Seattle Times – August 11, 2025, and August 18, 2025 Published Daily Journal of Commerce – August 11, 2025, and August 18, 2025
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REQUEST FOR PROPOSALS
Nelsen Side Channel Salmon Habitat Project
PROFESSIONAL ENGINEERING AND DESIGN SERVICES
1. Project Background
The Nelsen Side Channel Salmon Habitat Project (NSCSHP) is centered on a remnant, disconnected
section of the Green River south of I-405, at approximate River Mile 12.5 on the right bank, behind the I-
405 Levee #2005000056. Originally conceived as off-channel habitat in the 2005 WRIA 9 Salmon Habitat
Plan, the project has since grown into a strategic, multi-benefit initiative that reflects evolving regional
priorities for habitat restoration, flood risk reduction, and equitable access to open space. It is
supported by an array of policy frameworks and funding sources that reflect both ecological and
community-centered priorities, including:
• The Lower Green River Corridor Flood Hazard Management Plan PEIS
• King County Conservation Futures, King County Parks Open Space - River Corridors, King County
Cooperative Watershed Management, and Washington State Recreation and Conservation
Office Salmon Recovery Funding Board programs
• The City of Tukwila’s Capital Improvement Program and related planning documents
The project aims to provide off-channel rearing and high-flow refuge habitat for juvenile Chinook
salmon and other species, while incorporating flood risk reduction, urban open space, and public river
access.
The City intends to advance this Phase on an accelerated schedule to align with active funding timelines.
While flexibility may be available through coordinated extensions, proposals should reflect a strategy
that prioritizes early deliverables and measurable progress, with emphasis on timely advancement of
foundational documentation and design alternatives by the end of 2025, emphasizing progress to draft
status to demonstrate project momentum.
This RFP is structured to support efficient scoping and contracting. While it provides detail to inform
proposal development and future scope negotiations, the City welcomes consultant input on
sequencing, staffing, and level of effort.
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2. Project Scope of Work
The selected Consultant team will prepare Phase I Basis of Design and Alternatives Analysis. The City
anticipates that the scope will include, but is not limited to, the following task areas:
A. Base Data and Background Review
• Topographic and bathymetric survey, including integration of existing bathymetric data from
prior projects.
• Critical Areas Report in accordance with local and state requirements, including delineation of
wetlands, streams, shoreline jurisdiction, buffers, and priority habitat areas.
• Cultural Resources Technical Memo or Report, based on background research and coordination
with DAHP, tribal representatives, and applicable grant requirements..
• Access Plan and Easement Strategy: Review title reports, ROW information, and existing
easements to develop a coordinated access plan that supports long-term public, maintenance,
and construction access. The plan shall identify access constraints, evaluate new easement
opportunities, and recommend strategies for acquisition or shared-use agreements. It shall
include:
a) Pedestrian access from West Valley Highway using the existing sidewalk between
adjacent hotel properties. Coordinate integration of the NSCSHP entrance with the
pedestrian cul-de-sac at the western terminus of the sidewalk, including potential
enhancements for visibility, signage, and continuity of shared use.
b) Vehicular access through adjoining private property, including: (1) visitor parking near
the proposed site entrance in the vicinity of the existing pedestrian cul-de-sac, and (2)
maintenance vehicle access via the existing narrow opening between trees south of the
cul-de-sac. Assess feasibility of using this location as a service entrance. Consider
shared-use agreements or easement acquisition.
c) Shared-use access along the existing fire/emergency access road located behind
adjoining commercial properties, to support a pedestrian connection between NSCSHP,
the Tukwila Pedestrian Bridge, and the Green River Trail.
• Coordinate easement and access strategy with trail, pedestrian, and site design tasks identified
in Section C.
B. Geotechnical, Hydrology and Hydraulics
• Preliminary Geotechnical Assessment
• Levee setback feasibility assessment and concept design, including evaluation of type, size, and
location to inform early project development and permitting strategy. Consultant shall assess
potential Section 408 applicability based on levee status (#2005000056), recognizing that the
levee is not currently Federally certified. Coordination with USACE may be required depending
on federal interest or authorization history.
• Coordination with WSDOT Local Agency Office and Specialty Groups (Bridge, Hydraulics, etc.) for
expectations related to WSDOT development agreement for hydraulics and geotech related to
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downstream risks to I-405 bridge and walls associated with I-405 and Exit 1 Off-ramp, and
associated stormwater drainage.
• Screening-level flood modeling for the Nelsen drainage basin and Lower Green River, using
existing models and assumptions where feasible, to inform feasibility of levee setback and
habitat alternatives.
• Open channel hydraulic analysis, including screening-level assessment of sediment transport,
scour, erosion, and risks to adjacent infrastructure (e.g., I-405 Bridge), to inform habitat design,
levee setback feasibility, and long-term site stability. Grant agencies have identified sediment
deposition in off-channel habitat as a concern, and analysis should reflect this priority.
• Geomorphic assessment to inform site suitability, fill and grading scenarios, potential flow-
through feasibility, based on sediment dynamics, legacy channel form, and adjacent floodplain
conditions.
C. Habitat and Urban Design tasks are intended to inform the development and evaluation of design
alternatives under the Alternatives Analysis. The Consultant shall assess habitat, public access,
stormwater integration, and spatial design factors, and provide strategies, configurations, and
evaluation criteria to support the layout, comparison, and refinement of those alternatives.
• Prepare a site analysis (plan[s] and narrative) summarizing site constraints, habitat
opportunities, access feasibility, vegetation inventory, adjacent land uses, and floodplain context
and reconnection potential. The analysis shall inform spatial opportunities and limitations
relevant to the development of multiple design alternatives.
• Identify habitat design strategies and spatial configurations to be applied across alternatives,
including channel geometry, native vegetation zones, aquatic habitat structures, and bank
treatments. Coordinate with the geomorphic assessment and access strategy to ensure
feasibility and functional integration. Aquatic temperature management is a grant agency
priority and should be reflected in habitat design strategies.
• Evaluate site access configurations including pedestrian circulation, trail alignment options, and
parking locations. Identify potential public and maintenance access connections to adjacent
properties and roadways. Define circulation strategies that consider user experience, safety,
visibility, maintenance feasibility, and easement constraints. Evaluate potential for incorporating
an the existing fire/emergency access road (located behind adjoining commercial properties) as
a shared-use path connecting to the Tukwila Pedestrian Bridge and Green River Trail.
• Evaluate existing stormwater flows entering the project area from WSDOT right-of-way and
adjacent commercial properties. Identify opportunities and constraints for drainage integration,
water quality treatment, and long-term maintenance considerations within each alternative. The
City will provide available as-built stormwater records to support this task.
• Develop a vegetation strategy addressing habitat function, screening needs, viewshed impacts
(from and to the site), and compatibility with adjacent land uses (e.g., freeway, hotel). Identify
notable, significant, or historically/culturally significant trees or vegetation stands that may
influence layout options, provide ecological or aesthetic value, or warrant preservation within
the design alternatives.
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• Identify vegetation-related safety considerations, such as strike hazards and limited sightlines,
and recommend mitigation strategies consistent with CPTED principles and WSDOT
coordination.
• Identify opportunities for integrating cultural and historical features into alternative designs,
such as interpretive opportunities for the Gilliam Estate / White River Lodge and the historical
Gilliam Creek alignment.
D. Regulatory and Permitting Strategy
• Identify permitting pathway and timeline for the project, including but not limited to Shoreline
Substantial Development Permit, SEPA compliance, Section 408 review (if applicable), Hydraulic
Project Approval (HPA), and Floodplain Development Permit.
• Evaluate stormwater management implications and coordinate with City records, including
drainage easements and historical as-builts.
• Coordinate with WSDOT regarding downstream hydraulic impacts, stormwater discharge from
adjacent right-of-way, and other agency concerns affecting project development.
• Confirm the regulatory status of the I-405 levee (#2005000056), which is not Federally certified.
Assess Section 408 applicability based on federal interest, authorization history, and project
proximity to WSDOT infrastructure.
• Summarize permitting needs, agency coordination, and approval timelines into a table. Integrate
into the project schedule to support efficient phasing.
E. Stakeholder and Community Outreach and Engagement
• Serve as the primary lead for developing and implementing the Outreach and Engagement Plan,
coordinating with the City to ensure stakeholder, public, and interdepartmental input is
incorporated into the design process and reflected in the evaluation of project alternatives.
• Facilitate and document engagement activities, including community meetings, stakeholder
workshops, and interagency coordination. Summarize input received and highlight key
implications for design alternatives.
F. Alternatives Analysis
The Consultant shall prepare a standalone Alternatives Analysis Report that documents and compares a
minimum of three functionally and spatially distinct design alternatives, supported by technical rationale
and conceptual design figures sufficient to inform future refinement and permitting. The report shall
support the City’s decision-making process for future project phases by presenting a clear, side-by-side
comparison of options based on technical feasibility, habitat benefit, flood risk reduction, public access,
cost, and long-term operations considerations. No recommendation of a preferred alternative is
required at this stage.
The report shall include:
• Executive Summary
• Project Introduction and Goals
• Summary of Site Conditions, Constraints, and Green River Context
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• Summary of Stakeholder and Interdepartmental Input that influenced the development of
alternatives
• Design Criteria and Evaluation Framework
• Overview and Description of a minimum of three design alternatives, including:
o Narrative Summary and Rationale for each alternative
o Plan sets, with a minimum of three cross-sections per alternative
o Construction cost estimates (concept-level, recognizing early-stage assumptions)
• Comparative Analysis using both quantitative and qualitative evaluation criteria, including
discussion of:
o Habitat function and ecological benefit
o Flood risk reduction
o Public access and recreational use
o Construction cost
o Life cycle operations and maintenance (O&M) considerations
• Comparative Matrices summarizing relative benefits, risks, trade-offs, and scoring
• Preliminary Construction Schedule for each alternative, reflecting materially different phasing,
permitting, or implementation pathways
The Alternatives Analysis Report may reference technical materials included in the Basis of Design
Report (Section G) but should focus on clearly articulating the comparative performance and feasibility
of each alternative as a standalone decision-support document.
G. Basis of Design (BoD) Report
The Consultant shall prepare a standalone Basis of Design Report (BoD) that synthesizes technical
findings, site investigations, and stakeholder input developed throughout Phase I. The BoD will serve as
a foundation for advancing the project into future design, permitting, and implementation phases. It is
not expected to include a recommendation or refinement of a preferred alternative.
The BoD shall include:
• Executive Summary
• Summary of key findings from technical studies and site investigations
• Design assumptions and criteria applicable across alternatives
• Site access, stormwater, permitting, and constructability considerations
• Summary of stakeholder, community, and interdepartmental input relevant to project feasibility
and design considerations
• Preliminary construction schedule ranges and permitting implications for advancement of any
alternative
The following supporting documents shall be included within the BoD as chapters or appendices, as
appropriate:
• Access Plan and Easement Strategy
• Preliminary Geotechnical Assessment
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• Hydrology and Hydraulic Summary
• Critical Areas Report
• Cultural Resources Technical Memo or Report
• Habitat and Urban Design Strategy
• Permit Pathway Summary
• Community and Stakeholder Engagement Record
• Baseplan (survey, ROW, title)
The BoD should be developed in coordination with the Alternatives Analysis Report (Section F) and may
include references to technical assumptions or findings that informed alternative development and
comparison. The Consultant shall document how input from community outreach and stakeholder
engagement shaped project understanding, feasibility, and design considerations.
H. Project Management and Optional Future Services
• Develop and maintain a project schedule that aligns with major deliverables, coordination
needs, and City review timelines.
• Participate in regular coordination meetings with the City Project Manager (anticipated bi-
weekly) and prepare summary notes for City review.
• Perform additional project management tasks as mutually agreed upon by the Consultant and
City to support delivery of the defined scope.
• At the City’s discretion, and upon agreement between the City and Consultant, the Consultant
may be contracted under a future phase to advance the project into Phase II preliminary design
based on the outcomes of this Phase I scope.
3. Deliverables
All deliverables shall include Draft 1, Draft 2, and Final versions, unless otherwise noted. The City
anticipates internal and interdepartmental review cycles.
The Consultant shall propose a project schedule and delivery strategy that prioritizes early-phase work
to align with active funding timelines. The City’s near-term priority is to demonstrate tangible progress
toward foundational project documentation and alternatives development by end of December 2025.
To support this objective, consultants are encouraged to:
• Identify tasks that can be compartmentalized and completed early—such as survey and base
mapping, geomorphic assessment, preliminary geotechnical investigation, levee setback
feasibility analysis, Critical Areas Report, and access and easement strategy—and plan for draft
or final delivery by December 2025
• Initiate interrelated or iterative tasks—such as conceptual alternatives design, stakeholder
engagement, and access planning—with clear strategies to demonstrate meaningful progress
through annotated outlines, evaluation frameworks, partial drafts, or other planning artifacts
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• Coordinate the structure and sequencing of deliverables—Basis of Design Report and
Alternatives Analysis—to align with logical workflow, task dependencies, and grant timelines
While the City anticipates that several core work products (e.g., survey, geotechnical assessment, critical
areas report, geomorphic assessment, and easement analysis) may reach completion or Draft 1 status
by the end of December 2025, other components—such as community engagement documentation or
alternatives comparison—may remain in progress. These shall be carried into early 2026 and integrated
into the final Basis of Design Report (Sections A–G) and Alternatives Analysis, or submitted as
standalone documents, as appropriate.
The final project schedule, deliverable format, and content phasing will be confirmed during contract
negotiation and refined throughout the project in coordination with the City.
4. Evaluation Criteria
Proposals will be evaluated and ranked based on the following criteria (in order of importance):
1. Relevant project experience of key personnel
2. Project understanding and approach
3. Ability to manage interdisciplinary projects with stakeholder engagement
4. Demonstrated capacity to stage and deliver early-phase tasks in alignment with the December
2025 milestone outlined in Section 3
5. Team availability and staffing plan
6. Past performance and experience with similar habitat and flood risk projects
7. Experience with permitting pathways, community engagement, and equity integration
5. Proposal Submittal Requirements
• Limit proposals to 20 pages (excluding resumes and appendices)
• Include team composition, role of each member, relevant experience, and 3 references
• Submit 5 hard copies and 1 digital copy (PDF) by 5:00 p.m. PST on August 25, 2025
• Address proposals to:
Josh Hopkins
Surface Water Project Manager
City of Tukwila Public Works
6300 Southcenter Boulevard, Suite 100
Tukwila, WA 98188
Email: Joshua.Hopkins@TukwilaWA.gov
6. Reference Materials
Reference materials are available upon request to support proposal development or consultant
onboarding. Please contact the Project Manager listed in Section 5 to request access.
7. Project Schedule Expectations
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The City anticipates completing consultant selection by September 5, with scope negotiations finalized
by September 12 and Notice to Proceed (NTP) issued by the last week of September. This timeline
reflects the City’s desired schedule to initiate early-phase work in alignment with grant deadlines. If
these milestones shift, the project start may be delayed by a month. Proposals should reflect readiness
to mobilize quickly and adjust as needed to meet near-term deliverable priorities outlined in Section 3.
8. City Coordination Responsibilities
The City will provide:
• Real property Right of Entry
• Liaison support across departments (Parks, Community Development, Public Works)
• Shared coordination responsibilities with WSDOT, King County, Tribes, private property owners,
relevant community partners, and the public, as appropriate.
9. Reservation of Rights and Equity Statement
The City of Tukwila reserves the right to reject any or all proposals and to waive informalities in the
selection process.
The City affirms its commitment to nondiscrimination in accordance with federal, state, and local
regulations and encourages proposals from minority- and women-owned business enterprises (MWBEs).