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The Black River Pump Station is an integral part of the flood protection system on the lower Green River. It serves as a dam to keep high tides and Green River floods out of Renton and parts of Kent and Tukwila. The pump station lifts all drainage from the 24.8 square mile Springbrook Creek basin into the old Black River channel, which flows into the Duwamish River near Fort Dent Park.

Aerial image of the Black River Pump Station location.

The pump station began operation in 1972 after King County sponsored its design and construction by the Soil Conservation Service.  The station houses eight flood control pumps.  The primary pump (P-1) has a 200 horsepower electric motor that handles all of the flow most of the year.  The other seven flood control pumps are driven by diesel engines that total 7,800 horsepower.  The diesel engines are important during major flood conditions, and one or two often run to pass storm flow, but most of the year they are quiet.

The flood control pumps are accompanied by numerous support systems, including provisions for both upstream and downstream fish passage.  An Alaska Steeppass (Denil) fish ladder allows adult fish to migrate upstream past the station, and an airlift system allows juvenile fish to migrate downstream.  Apart from these mechanical fish passage systems, the pump station is a complete barrier to fish passage. 

The pump station has not had many improvements in its 45 years of service.  Most of the original systems are still in use, while some systems have been improved in response to problems that arose.  All systems have been included in a general condition assessment and capital project planning effort. Based on that work, extensive renovations are planned for all of the mechanical systems in the station.

The design team will first examine the foundation and its ability to resist expected earthquake forces, which are now much better understood than when the station was designed. In addition, the design team will work to bring the fish passage systems in line with modern design standards. Schedule milestones and detailed project planning documents follow below.

Capital improvement schedule milestones

Following are the best available projections of capital project timing. Schedule details may be adjusted as design analyses are completed.

Hire design consultant Nov. 2018
Seismic and fish passage memos Mar. 2019
Select seismic and fish passage alternatives                 Aug. 2019
Replace high-use pump engines Aug. 2020
Replace control building 2022
Support system upgrades 2023
Fish passage improvements 2024
Fish screen extensions 2026
Replace large engines 2028

Condition assessment and capital improvement planning

The following series of technical memos 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.

Background information

Image of water being pumped from the Black River Pump StationWater pumped from the Black River Pump Station


Image of the new double-walled fuel tanks outside the stationNew double-walled fuel tanks outside the station were installed in 2014


 New double-walled fuel tanks for each pump within the Black River Pump StationNew double-walled fuel tanks for each pump within the station were installed in 2014

Sediment removal project

Accumulated sediments had blocked much of the inlet channel to the station.  Sediment removal was completed in 2016.

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