Westside High Flow Pump Station and Forcemain Improvements
The WRA Interceptor Phase 27 Project (“Eastside Interceptor”) consists of eight major segments. Segments 1 through 5 encompass a gravity interceptor sewer from Union Park, through the east side of Des Moines to the Wastewater Reclamation Facility (WRF). Segments 6 and 7 encompass a 42-inch diameter pressure force main from the Westside Pumping Station to the gravity sewer at Union Park. Segment 8 involves the construction of a new High Flow Pump Station on the Westside Pumping Station Property. HR Green has provided design and construction phase services for Segments 6, 7 and 8 of the Eastside Interceptor project.
Force main design included nearly 8,500 LF of ductile iron pipe, including a crossing of the Des Moines River. The force main then traverses Birdland Park, and is located adjacent to a US Army Corps of Engineers (USACE) flood protection levee, as well as a historic cemetery.
Segment 8 of the project includes modifications to the existing Westside Pumping Station and Equalization Basin. These modifications will add 35-45 mgd of high flow pumping capacity, increasing total pumping capacity to 80 mgd. The High Flow Pump Station will be retrofitted within the existing equalization basin configuration.
HR Green completed system curve hydraulic calculations for pump selection and transient analysis for the force main. A “dipping tube style” surge tank was located at the High Flow Pump Station as well as strategically located pressure relief devices along the force main to mitigate pressure fluctuations. Force main interconnection provisions were provided, allowing either pump station to utilize either new or old force main. USACE approval was required for the High Flow Pump Station siting and force main designs. HR Green provided construction sequencing and planning allowing construction to align with the large gravity interceptor design that will convey the force main flows to the WRF. (Gravity interceptor work was completed by other consultants.)
HR Green was responsible for civil/structural and M/EP design, as well as permitting for the project. The project is currently in construction with HR Green providing admin services.