Large storms create challenging hydraulic conditions that must be managed for successful treatment outcomes in CSO facilities. Technology is key to understanding how to best manage and treat these variable wet weather flows. The 160-MGD Saddle Creek CSO High Rate Treatment Basin is a critical component of the City of Omaha’s efforts to treat a minimum of 85% of its wet weather flow in a typical year per the Long Term Control Plan’s requirement. The facility is sized to capture nearly 3.3 MG of CSO and includes grit removal, screening, TRC- and flow-paced disinfection, settling, and dechlorination processes to kill bacteria and remove residuals of the treatment process. Dewatering of this gravity-in/gravity-out facility is accomplished with submersible pumps, and flushing gates are provided to prevent debris accumulation and odor formation between storm events.

Advanced hydraulic modeling—numerical, computational fluid dynamics, and physical modeling of the intake structure and basin layout—was essential to meeting all required treatment needs while streamlining flow through the tank. Sophisticated real-time control technology and instrumentation was employed to maximize flow to the downstream sewer system to prevent unnecessary operation of the tank during smaller storm events while ensuring the downstream interceptor sewer has adequate capacity. Our team used 3D BIM design technology to reduce the potential for conflicts and improve cost estimation.

Awards
ACEC National Grand Award, 2025
ACEC Nebraska Engineering Honor Award, 2025
APWA Nebraska Project of the Year Award (Environmental Over $75M), 2024