A Reservoir for the Future

Tucson Water’s 60-million-gallon Clearwell Reservoir is Arizona’s largest potable concrete reservoir and conveys two-thirds of the City’s water supply each day. The HDR team rehabbed the two-cell facility over three years by constructing shear walls, adding carbon fiber wrapping, modifying structural steel to upgrade its seismic performance and installing a new liner and roofing system.  

We used drones to find imperfections and deflection in existing structural steel members, which accelerated shop drawing and procurement processes; allowed the structural team a safe and effective inspection method; and eliminated the need to cut and field-fit steel during installation.  

To minimize environmental effects, the team moved several large Saguaro cacti and constructed a specialized animal fence around the construction site. Located near a luxury resort, the team worked with the community to avoid complaints and concerns, and added amenities for a popular trail as a gesture of goodwill.  

We overcame the project site’s mountainous location, uncertain foundation and Arizona’s blistering temperatures. We overlapped several construction trades at once, using a unique sequencing effort to complete the project within the low system demand months. Conducted like a symphony, careful management and scheduling were orchestrated to keep the project moving forward.  

Completed on time and under budget, the new, water-tight Clearwell Reservoir will provide Tucson with clean drinking water for decades to come.