Northwest Outfall Siphon Rehabilitation

The Northwest Outfall Siphon Rehabilitation Project in Tucson, Arizona, led by Pima County RWRD, addressed odor and design issues in a 30-inch and 39-inch dual-barrel sewer siphon under the Santa Cruz River. Dibble devised corrosion-resistant structures to smooth flow and prevent corrosive gas release. Hunter Contracting Co. facilitated digital collaboration, surpassing expectations in aligning with the project vision. The scope included a flow management plan with a 270-foot temporary bridge, demolition of Silverbell Siphon structures, installation of new fiberglass-lined precast structures, a 48-inch storm drain, headwall, and access route. Project elements encompassed traffic control, surveying, quality testing, public relations, and carbon fiber wraps. Restoration efforts considered impacts on the Silverbell Golf Course and The Loop bike path, achieving success in odor control while enhancing regional infrastructure resilience and environmental considerations.