Design of High-Capacity Flood/Stormwater Pump Station Projects: Delivery Methods, Challenges, Solutions, and Lessons Learned

The purpose of this presentation is to provide insight to other engineers for the design of high volume, low head stormwater pumping stations. Two case studies will be discussed that illustrate innovative solutions developed using traditional design-bid-build and alternate design-build methods. Lessons learned will be presented to provide engineers guidance when considering similar projects.

The first case study is the Paddy’s Run Flood Pump Station (FPS) designed by HDR for the Louisville, Kentucky Metropolitan Sewer District using the Progressive Design-Build (PDB) delivery method. Paddy’s Run FPS includes a total of eight (8) vertical mixed flow type pumps with a flow capacity of 1,900 million gallons per day (MGD) and a total of 21,000 rated horsepower. The PDB model was selected to promote innovative design, support Owner and Design-Builder collaboration, and meet strict schedule requirements associated with a Consent Decree program. PDB method provides the Owner the ability to select a pump manufacturer and equipment based on best value, not just the lowest capital cost. The design was exceptionally unique to utilize a opposite/offset layout to minimize impact to the levee system where the pumps/motors are located across from one another within the building structure, and the influent channel/wetwell is centered below the main operating floor between the formed suction pump intakes.

The second case study includes the Able No. 3 Stormwater Pump Station (SPS) designed by HDR for the City of Dallas, Texas that was delivered via traditional design-bid-build method. Able No. 3 SPS, increased the existing pumping capacity nearly fourfold to 1,270 MGD or 1,960 CFS. Able No. 3 SPS is the highest capacity pump station in the United States which utilizes four (4) 4,000-HP concrete volute type pumps and can convey over 1.3 billion gallons per day or fill an Olympic swimming pool in 45 seconds. The pump station provides flood protection for 3 square miles for Downtown Dallas including over $13.7 billion of homes and businesses. Also, the facility serves to lower the flood elevation and opens an additional 128 acres for new development. A few challenges including very poor hydric soils on the construction site and extensive groundwater mitigation and management system to protect its pier foundation will be discussed. Able No. 3 SPS has been operating successfully for about three (3) years as it was commissioned in late 2019.