Spokane St. Pump Station Improvements 

The station was constructed in 1928 to pump potable water from Seattle reservoirs to storage facilities throughout West Seattle. 

The scope of the improvement project includes the replacement of the existing above grade potable water pump station structure with a new structure and expanded footprint to include architectural, structural, mechanical, HVAC, plumbing, electrical, and instrumentation, controls, and security work. 

We designed the electrical power, lighting, and control system for the station which required a complete 4160V electrical system replacement and extensive building remodeling. As part of the electrical and control systems preliminary design task, our engineers performed a life-cycle cost analysis to compare alternatives to the existing method for flow control. The current system relies on throttling valves to limit the discharge pressure from the two 400 hp fixed-speed pumps. We evaluated both variable frequency drives and a method that relies on a magnetic clutch between the fixed-speed motor and pump to vary the pump speed.