Tucson Boulevard Diversion Structure

The El Rio Vista Natural Resource Park in northern Tucson grappled with challenges stemming from an aging Pima County Wastewater sewer structure, leading to sewage odor and corrosion issues. Featuring a 90-degree bend and six connections ranging from 18 to 54 inches, the structure caused excessive turbulence and off-gassing, resulting in unpleasant odors and resident complaints. Years of hydrogen sulfide exposure led to corrosion, compromising concrete and rendering stop gates nonfunctional, necessitating confined space entry into a hazardous gas environment for maintenance. Pima County RWRD, in collaboration with Dibble and Hunter Contracting Co., addressed these issues through the Tucson Diversion Structure project, implementing a corrosion-resistant system with a composite diversion structure, nine polymer manholes, and fiberglass pipes. This initiative ensures ongoing sewer service, diminishes overflow risks, enhances safety, and mitigates odors in midtown Tucson, creating a more efficient gravity system. The comprehensive project also involved a sewer bypass capable of handling 20.25 million gallons of raw sewage daily, along with significant pavement removal and replacement, including a temporary above-ground sewer bypass, excavation, and replacement of the diversion structure and 1,200 linear feet of 54-inch pipe. Additionally, Hunter Contracting Co. replaced 18,000 square feet of roadway and installed concrete bank protection for improved drainage.