RFI for MDSCO Chelan Wet Weather Storage

Background
King County is issuing a Request for Information (RFI) to gather insights from interested and qualified firms for General Contractor/Construction Manager (GC/CM) Services related to the Chelan Wet Weather Storage Project.

The Wastewater Treatment Division (WTD) of King County, which employs over 800 people, is responsible for planning, designing, building, and operating treatment facilities while enforcing regulations to protect water quality. This RFI aims to inform the County's application to the Capital Projects Advisory Review Board (CPARB) Project Review Committee (PRC) and future solicitation development.

Work Details
The project scope includes:
1. Construction of a 7-million gallon grade combined sewer overflow (CSO) storage tank.
2. A diversion structure.
3. Demolition and replacement of the Chelan regulator station.
4. Installation of approximately 2,600 lineal feet of open-cut and trenchless (micro-tunneling and pipe ramming) influent 60-inch pipe.
5. Submersible drain pumps to discharge wet weather flows from the storage tank to the effluent conveyance system, which will discharge to the West Duwamish Interceptor for treatment at the West Point Treatment Plant.
6. Construction sequencing will utilize a top-down construction method with interior and exterior slurry walls, multiple phases of excavation, dewatering for various excavations, permanent ground anchors, and ground improvements for seismic mitigation.

Period of Performance
Preconstruction services are targeted to start in the 3rd quarter of 2026; construction services are targeted to start in the 3rd quarter of 2029.

Place of Performance
The project will be performed in King County, Washington.

Bidder Requirements
Firms must register in the E-Procurement Supplier Portal to participate in this RFI. Responses are voluntary and will not affect future solicitation eligibility.