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Project updates

  • High Use Engines Construction in progress as of spring 2021.
  • Fish Passage Improvement Alternatives Analysis in progress as of November 2021.
  • Seismic and Structural Alternatives Analysis in progress as of November 2021.
  • P1 Pump is reinstalled and will be operational by spring 2022.

Project overview

The Black River Pump Station is an important structure of the Green River flood control system. The pump station must work reliably to provide flood risk reduction benefits to the highly developed and largely commercial portions of Renton, Kent, and Tukwila. After almost 50 years of continual operation, the pump station requires rehabilitation to meet current standards to ensure safe, reliable, and efficient operations.

Black River Pump Station shown on a map near the Green River with Tukwila to the west and Renton to the east.
View a larger version of the map.

The Natural Resources Conservation Service built the Black River Pump Station in 1970 in partnership with King County, and the facility has operated continuously since 1972. The station protects over 2,800 acres with an estimated 370 structures in Renton, 210 structures in Kent and 60 structures in Tukwila, and an estimated $4.4 billion in assessed value.

The station contains eight flood control pumps. The primary pump (P-1) has a 200-horsepower electric motor that pumps the majority of the flow during the year. The other seven flood control pumps are driven by diesel engines and are important when major flooding occurs. Most of the year the diesel engines and pumps are not in use. The station also includes several support systems; including systems to allow fish to pass both upstream and downstream.

A tan building straddling the river spouts water.
Water is pumped by the Black River Pump Station downstream toward the Green River during high flows.

Project purpose and goals

Improvements to the Black River Pump Station will help to ensure that the station continues to provide flood risk reduction benefits to this economically vibrant area, and fish passage improvements will provide better access to habitat and support long-term recovery goals for salmon and steelhead populations.

The project is based on the three goals of the 2006 King County Flood Hazard Management Plan:

  1. To reduce the risks from flood and channel migration hazards.
  2. To avoid or minimize the environmental impacts of flood hazard management.
  3. To reduce the long-term costs of flood hazard management.
Large, white double-walled fuel tanks on dirt.
View of some of the pumps inside the station.

Capital Project Strategy

To ensure the pump station continues to provide flood risk reduction benefits and operates safely, reliably, and efficiently, a capital project strategy was developed and approved in September 2020. The capital project strategy is based off the technical memo developed in 2019 and guides planning, design, and implementation of improvements. Current capital project strategy work elements include:

  • Replace High-use Engines
  • Seismic & Structural Improvements
  • Fish Passage/Fish Exclusion Improvements
  • Mechanical System Upgrades
  • Replace Control Building
  • Replace Large Pumps
  • Sediment Management

Capital Project Strategy Alternatives and Evaluation Criteria Technical Memorandum, December 2019 (7.83 MB, PDF)

Schedule milestones 

Planning, designing, and implementing upgrades began in 2018 and will occur over seven to 10 years. High level milestones are identified in the table below.

Activity Start date
Seismic and fish passage preliminary analyses  2019
Fish passage improvements: outreach and early actions  Summer 2020
Replace high-use pump engines Spring 2021
 Mechanical system early action repairs Fall 2021
 Replace control building alternatives analysis Planned 2023
 Seismic and structural design Fall 2023
 Replace large pumps alternatives analysis Planned 2024
 Fish passage improvements Planned 2025
 Replace large pumps Planned 2026

Fish passage/fish exclusion improvements

The Black River Pump Station was built and began operation prior to the Endangered Species Act listing of Puget Sound Chinook and steelhead, and concerns have been raised about the station’s impact on fish. Facility improvement efforts offer an opportunity to better the pump station’s fish passage systems. The input of technical stakeholders and tribal representatives regarding fish passage needs at the pump station is essential to the success of improvements. Early engagement started in 2020 with phone calls, briefings, and two remote work sessions. Additional input will be requested as improvement alternatives are developed.

High-use engines

Pump 1 (P1) being removed from the Black River Pump Station.
The middle section of P1 pump column is pictured above being removed for refurbishment.

Construction to replace the high-use engines and overhaul the most frequently used flood pumps began in March 2021. Construction is expected to be completed by December 2022.

The environmental impact comment period for this action was April 3-17, 2020.

Seismic and structural improvements

Geotechnical explorations were completed in summer 2020. Results from the explorations are documented in the Geotechnical exploration Report below. Alternatives Analysis for Seismic and Structural retrofits is in progress. A preferred alternative will be identified in February 2022.

Sediment management

In 2020 and 2021, multiple storm events moved more sediment into the forebay at BRPS, requiring an urgent response to address damage to the fish screens. These sediment loads highlight the need to proactively manage sediment in the forebay and area upstream of the station to maintain effective fish screen operability and flood management responsiveness. As a result, alternatives for better managing sediment have been refined.

Mechanical system upgrades

Initiating early action repairs in 2021.

Replace control building

Initiating Alternatives Analysis in 2023.

Replace large pumps

Initiating Alternatives Analysis in 2024.

Project documents

The following series of technical memos were completed in 2015 and document the condition of the pump station and identify priorities for capital improvements. The capital improvements listed above were first recommended in the memos below.

Sediment removal project

In 2016, sediment that had accumulated and was blocking much of the pump station’s inlet channel and reduced flood storage was removed.

For more information about the Black River Pump Station, please contact Tom Bean, River and Floodplain Management, Department of Natural Resources and Parks.