Midway Creek Project Feasibility Analysis and Conceptual Design
Request for Proposals
Project Manager: Erik Rigaux
erik@midsoundfisheries.org
(240) 425-3837
Date Released: July 1, 2025
Submission Deadline: August 15, 2025 @ 5pm
Project Overview:
Mid Sound Fisheries Enhancement Group (Mid Sound) has secured funding to complete an initial feasibility analysis and conceptual design for removing a derelict 43” corrugated steel culvert on Midway Creek in Kent, Washington. Midway Creek flows into the Green River at river mile 19.5, and the stream below the culvert has been documented to have significant juvenile Chinook usage. The project goal is to remove the abandoned culvert preventing fish passage, and open up access to ~800’ of stream and one of the largest and highest quality floodplain wetlands (~12 acres) in the Lower Green River basin. Removing the culvert would open off-channel rearing and flood refuge habitat for ESA-listed Chinook and other salmonids in a wetland and stream that are protected by Seattle Public Utilities (SPU) ownership. The Midway Creek and wetland complex is a Tier 1 restoration area (Project LG-33 in the WRIA9 Salmon Habitat Plan 2021 Update).
A feasibility study will explore how to remove the culvert while protecting the stream and wetland from contamination from a nearby leachate pond, protecting SPU Solid Waste Infrastructure, maintaining the integrity of the active upstream beaver dam, and navigating the slope/water drop from the culvert. The feasibility will include an historical literature review, site survey, habitat assessment, concept-level geotechnical survey report, hydraulic modeling, and existing conditions report. The project will produce two conceptual design alternatives and preliminary cost estimates. A preferred alternative will be selected and the process documented in a design memo.
Background:
Mid Sound is a non-profit 501(c)(3) organization focused on salmon habitat restoration. Since 1991, we have been working with partners and jurisdictions to plan and construct restoration projects. We are partnering with Seattle Public Utilities, which owns the project site and the nearby landfill facility, on the Midway Creek Project Feasibility Analysis and Conceptual Design Project with an aim toward future restoration of important wetland habitat for Chinook salmon.
The property on which the culvert sits is the 60-acre Midway Landfill site, a former gravel quarry operated by SPU as a municipal solid waste landfill from 1966 to 1983. The landfill accepted demolition materials, wood waste, and industrial wastes. Landfilling activities contaminated groundwater and air with hazardous chemicals. Following cleanup, operation and maintenance activities and monitoring are ongoing. The culvert is outside the area that had been used as a landfill, but is in close proximity to a leachate pond. SPU does not have recent soil or water samples taken from the area immediately surrounding the culvert. This project includes studies to describe existing conditions around the culvert in order to ensure options for culvert removal will keep the creek, valuable fish habitat, and infrastructure protected during and after.
Schedule and Available Information:
| Date | Task |
| July 1, 2025 | Request for Proposals advertised |
| July 1, 2025 – August 8, 2025 | Firms may ask questions in the linked Google Sheets document. They will be answered in the same document in the order they were received. |
| August 6, 2025 @ 1pm – 2:30pm | Q&A Session with Mid Sound |
| August 15, 2025 @ 5pm | Proposals must be submitted by 5pm on August 15, 2025. Proposals submitted after 5pm on August 15, 2025 will not be considered |
| August 18, 2025 – August 22, 2025 | Proposal reviews and interviews |
| August 25, 2025 | Final selection and notification. Contracting begins |
| September 30, 2026 | Contract ends |
- Mid Sound has funding up to $77,000 for consultant fees for the scope of work included in this RFP. Funding was secured through King County’s Cooperative Watershed Management grant funds. While this RFP is for Feasibility Analysis and Conceptual Design, we are working to secure funding through final design. At Mid Sound’s discretion, we may continue to contract with the same firm for future design phases
Scope of Work
Project Goals:
The goals of this project are to: (1) Perform field reconnaissance and collect site data that will inform feasibility analysis for the removal of the culvert and the protection of Midway Creek and the wetland complex from leachate contamination; (2) Develop permitting and cultural resources plans to inform next steps; (3) Develop a project area base map and two conceptual design alternatives; (4) Create preliminary cost estimates for each design alternative; (4) Develop a brief feasibility memo that addresses pros and cons, project challenges, and expected outcomes for each conceptual design alternative; (5) Assist Mid Sound as needed to secure future project funding.
Project Tasks:
- Field Reconnaissance and Data Collection:
- Topographic Survey of leachate pond and culvert
- Historical literature review
- Existing conditions report
- Wetland delineation and flagging in proximity to culvert (area of proposed earthwork)
- Bankfull width estimate
- Other as recommended
- Develop Conceptual Design Plan and Preliminary Cost Estimate:
- This design plan will include two alternatives, and a preferred will be selected.
- Plans should include cost estimates for each alternative.
- Feasibility Memo:
- Should include pros and cons of alternatives relative to expected project outcomes.
- Geotechnical and HAZMAT preliminary and quantitative analysis
- Preliminary desktop analysis
- Qualitative slope stability analysis and summary memo
- Field exploration with equipment (borings)
- Lab testing and summary memo
- Cultural Resources and Permitting Support
- Provide Cultural Resources assessment using geotechnical data to the extent possible
- Permit matrix
Other Consultant Responsibilities
- Manage the contract so that all tasks are met and contract terms and conditions are satisfied within the proposed budget and schedule.
- Attend regular check-ins with the Project Team (Mid Sound, SPU, and consultant) to provide updates on project progress and align with project sponsor needs and direction.
- Submit invoices monthly. Invoices shall be itemized by tasks with subtotals. Task hours shall be billed in quarter hour increments and itemized by billing rate. Invoices shall also include a summary and progress report.
Evaluation Criteria
Consultant Qualifications
Mid Sound is seeking a consultant or team of consultants with experience and expertise in site assessment, feasibility analysis, design, and HAZMAT analysis. Required items to be included in the proposal are listed under Format for submissions.
Consultant Selection Process
General Approach:
Mid Sound and Seattle Public Utilities intend to convene a panel for the RFP review process. This panel will be composed of staff from Mid Sound, including Project Manager and Executive Director(s); staff from Seattle Public Utilities; and a representative (or representatives) from WRIA 9. This Panel will select a consultant based on the submitted materials and abilities of the firm/team and key staff. Proposers may be individual firms or teams as appropriate to meet the specific needs of the project. Proposers are solely responsible for all costs incurred in the development and submission of the response statement to this RFP or for any subsequent requirements of the consultant selection or contract negotiation process. All materials submitted in response to this RFP become the property of Mid Sound.
Selection Process:
Step 1
Written proposals will be evaluated and the highest scoring firms invited for an interview.
Step 2
Mid Sound will review and select the top candidates based on a combination of written proposals and interviews and begin negotiations with the selected Respondent. If the selected Respondent and Mid Sound are unable to agree on the final scope and fee for the contract, Mid Sound reserves the right to terminate the negotiations with the selected Respondent and initiate contract negotiations with another Respondent.
Format for submissions:
Limit proposal to no more than 6 pages of text, with consecutively numbered pages, using 11-pt type or larger. The RFP, cover letter, table of contents, and resumes are not included in the 6-page limit. All pages shall be numbered, including resumes and appendices, and listed in a table of contents. Please organize proposals in the following format.
- Cover letter that includes the name, phone number, and email of a main point of contact.
- Table of Contents that includes any appendices.
- Description of technical expertise relevant to the Scope of Work.
- Outline of experience conducting site assessments and designing and implementing similar projects, and success in implementing other tasks outlined in the Scope of Work.
- Approach to meeting the scope of work, including roles and experience of any partners or subconsultants on the proposed team.
- A proposed project budget that includes expense categories and their amounts.
- Description of similar projects performed by the consultant team, including the team’s role and references.
- Resumes and availability of key staff.
Submittal Guidelines
- Please submit your proposal including one (1) signed copy of the entire RFP package.
- One (1) signed copy of any addenda issued.
Email to erik@midsoundfisheries.org by 5pm on August 15, 2025. For questions, please contact Erik Rigaux at (240) 425-3837 or erik@midsoundfisheries.org.
Questions regarding this project should be posted in the linked Google Sheets document to which all firms will have access. Responses to submitted questions will be answered in the order they were received. Mid Sound will also hold a brief project info presentation and Q&A via Zoom on Wednesday, August 6th, 2025 from 1pm to 2:30pm. This meeting will be recorded and made available on our website. To ensure that all firms receive the same information, Mid Sound will not meet one-on-one with firms. Please attend the open session and/or ask questions in the spreadsheet made available for this purpose. The table on page 2 lists the submittal and selection process schedule.
Mid Sound reserves the following rights for acceptance, modification, and/or rejection of submitted proposals:
- Rejection of any and all proposals.
- Rejection of any proposal not in compliance with proposal requirements.
- Providing addenda, amendments, supplementary material, or other modifications to the proposal specifications.
- Cancellation of this Request for Proposals without issuance of another Request for Proposals.
- Issuance of subsequent requests for new proposals.
- Request for submission of further information by proposers in order to complete evaluation.
- Determination to select one or more proposers for attempted negotiation of a final contract.
Figures:
Fig. 1 Midway Creek Vicinity Map.
Fig 2. Midway Creek Map with Points of Interest outlined
Fig 3. Midway Creek Map with labels.
Fig. 4: Culvert, looking from downstream side
Fig 5: Culvert surface/abandoned road bed