Williams – Concrete Labyrinth Spillway & Weir Box Construction

Williams, AZ – DBA was responsible for the construction of the first labyrinth weir structure in the State of Arizona.  This project included safety modifications to reinforce and raise the existing earthen dam to meet specifications of the Arizona Department of Water Resources, the U.S. Bureau of Reclamation, and the U.S. Army Corps of Engineers.  Modifications included the installation of a toe drain system, weir box, and a sand chimney.

• Major elements included:
• Earthen embankment (8,000 CY)
• Placement of rip-rap (1,000 CY)
• Rock-fill buttress (1,500 CY)
• Washed concrete sand (2,500 CY)
• Installation of a cast-in-place concrete weir box
• In order to meet the required specifications of the Army COE, concrete surface finishes had to be F2 and F3 types and the tolerable allowances were less than 1/4”.

Early in the project, the team discovered abandoned pipe that ran from the reservoir and continued under the dam.  It was eventually decided that it had been a waterline previously installed to service the City of Williams that had never been fully completed.  The project specifications required that the pipe be filled with a “mechanically-foaming concrete” material.  The project was contracted through Rummel Construction as the General Contractor.