Connection to the Fairgrounds Wastewater Reclamation Facility to the Conveyance System

Designing a sewer and a water main extension with an automated flushing system instead of a costly lift station and force main.

Pima County desired to bypass an existing wastewater treatment facility (lagoon) and build a connection from the County Fairgrounds Site to their existing sewer system approximately three miles away. Dibble collaborated with the County to evaluate various connection alternatives, which included gravity sewer, force main, and combination systems. Our team worked together to review historical flow-monitoring data, update future flow projections, and provide a cost-effective gravity sewer solution that allows for future growth. The final design also included a diversion structure that provides flexibility in managing system flows. A conceptual study was performed ten years prior and recommended an interim lift station, wastewater storage tank, and force main.

Pima County Fairgrounds Aerial

Details

Client
Pima County

Location
Pima County, AZ

Scope
$6 M


Project Lifecycle

Dibble prepared an alternatives analysis to evaluate other viable options for conveying wastewater to the County’s conveyance system at Rita Road and Interstate-10 (I-10). Per the alternative’s analysis, Dibble recommended the design of a 15-inch gravity sewer and a water main extension with an automated flushing system instead of a costly lift station and force main.

Watermain Extension with Gate Valves

Dibble designed approximately 3 miles of 15-inch gravity sewer to connect the Pima County Fairgrounds to the existing conveyance system. Dibble modeled the system and designed approximately 1,660 feet of 6-inch water main and a flushing station to help the County operate and maintain the new sewer. Dibble led the design and permitting for the project and provided limited construction administration services.