Prison Hill Siphon Cleaning Project

Alvarez & Shaw, Inc. was selected by FEDVET Construction to perform critical cleaning and material-removal work for the Bureau of Reclamation’s Prison Hill Siphon in Yuma, Arizona.

The project involved cleaning the full interior of a 10-foot-diameter siphon pipe extending approximately 3,050 feet. Crews were responsible for removing sediment from the canal lining and hauling away an estimated 1,335 tons of nonhazardous material.

During the cleaning process, the crew encountered a unique equipment challenge. The bottom of the skip loader’s standard bucket was flat, while the interior of the siphon was round. This made it difficult to reach the curved edges and thoroughly remove the accumulated debris.

Rather than allowing the equipment limitation to slow the project down, Alvarez & Shaw owner Chase Alvarez designed and fabricated a custom bucket with a rounded bottom. The new bucket fit directly against the curved interior of the pipe, allowing the crew to scrape the siphon liner more effectively and remove debris that a standard bucket could not reach. This custom solution improved the cleaning process and demonstrated the hands-on problem-solving and field experience Alvarez & Shaw brings to challenging projects.

Communication presented another major challenge. Reliable communication between crews was critical to maintaining safety and coordinating work inside the 3,050-foot underground siphon. However, the underground environment blocked normal cellular signals, making phones and traditional communication methods unreliable.

To solve the problem, a Wi-Fi mesh communication system was created and installed throughout the siphon. Mesh pods were strategically placed along the inside of the pipe and outside the siphon to carry a reliable connection through the underground work area. This gave crews a dependable way to remain connected, coordinate equipment movement, and communicate important safety information while working deep inside the structure.

The project also had an extremely demanding schedule. All onsite cleaning had to be completed within a strict two-week outage of the Main Outlet Drain Exchange (M.O.D.E.) Canal. This required careful planning, reliable equipment, and close coordination among the entire project team to maximize every available workday.

Before cleaning could begin, Alvarez & Shaw provided the labor and equipment necessary to install an earthen plug at the canal inlet, helping ensure that water flow into the siphon was stopped. Material removed from the siphon was then given adequate time to dry before being loaded, transported, and properly disposed of. Disposal tickets, manifests, and waste-diversion documentation were maintained to account for the debris removed from the project.

Because crews were working inside a long, enclosed siphon, confined-space safety was a central part of the operation. Employees received the required training and personal protective equipment, including head, eye, hearing, hand, respiratory, and foot protection. As a federal project, the work also required Davis-Bacon prevailing-wage compliance and weekly certified payroll reporting.

The Prison Hill Siphon project reflects Alvarez & Shaw’s ability to take on demanding civil construction work involving heavy material removal, specialized equipment, confined-space conditions, federal compliance, and strict schedules. More importantly, it demonstrates the ingenuity and determination behind the company. When traditional equipment and communication systems could not meet the project’s needs, Alvarez & Shaw created practical solutions that kept the work moving safely and efficiently.