Despite the challenges of undertaking a massive project in the desert heat, a 130-year-old canal is now lined with concrete thanks to a project that was completed during an impressively short timeframe.
Close to 29,000 cubic yards of concrete, supplied by CEMEX, was used by Brosamer & Wall Inc. at the San Carlos Irrigation and Drainage District’s $52 million Phase 2 of the Florence Canal Reach 2 Rehabilitation and Lining Project that will be fully delivered next January.
The work is taking place in Arizona’s Pimal County and the once dirt canal is now lined with concrete. Before the concrete could be poured, B&W had to excavate nearly 300,000 cubic yards of earth and rock.
Due to serious seepage losses, canal management authorities initiated the project to improve water management, conserve water, and improve delivery systems.
“These upgrades update the aging structures, improve the hydraulic efficiency of the system, and minimize canal system water losses,” said Shane Lindstrom, SCIDD’s General Manager. “We are also installing five new check structures, 27 turnouts and modern electronic and manual flow measurement systems.”
B&W crews removed some canal structures, such as gates. The work also had crews install embankment, construct reinforced concrete structures, trim the canal and for the lining they had to use fibrous reinforcing, along with placing reinforced concrete pipe and 54 and 78-inch concrete siphon pipe extensions.
Having access to the canal was crucial for the work.
“The San Carlos Irrigation and Drainage District dries it twice a year – in mid-October for six weeks and then returns the water for four weeks, followed by another five dry weeks,” said Russell P. Gonzalez, B&W’s Project Engineer. “We put in long hours during those weeks to ensure everything was done within the timeframe. We used a 3,000 PSI mix for the concrete. With these types of canals, it requires a certain level of air for the mix and a fiber in the substrate of the concrete that one does not normally see in other projects.”
The remaining work includes installing one more structure, electrical, and solar equipment and road crossings.
Less than ideal conditions
Arizona’s hot summers are not conducive for paving, and hot weather concrete placement can make for difficult work.
“It gets up to 110 and 120 F,” said Gonzalez. “In April and May, we began paving around 11 p.m. and finished around 5 or 6 a.m. CEMEX added ice to ensure the mix remained cool and placed sprayers on the drums on the outside to keep it cool.”
Electrical and gas utilities were relocated and soul upgrades were necessary to pour concrete.
“The goal was to stay on schedule for the lining,” said Gonzalez. “We widened it and built up the canal and, where a new alignment was being put in, we constructed new portions.”
The first season ran from August 2020 to January 2021, covering six miles.
“We then started at the beginning due to land acquisitions and utility relocation in the middle portion of the project,” said Gonzalez. “Last August we were working in the middle and by January finished all the paving.”
The concrete lining, four inches thick, cured in three days.
Jensen Precast supplied the precast concrete elements. The elements for the turnout structures could be produced between five and seven days. A 250-ton hydro crane lifted many of he prefabricated pieces.
The 36-inch and 24-inch reinforced concrete pipes for the turnouts were supplied by Forterra. Eight feet in length, they were light enough to be moved about by excavators. As noted, 54-inch and 78-inch reinforced concrete low head pressure pipe were installed.
The canal management authorities diverted water in some locations to give crews access to the site.
“We were, on average, paving nearly 3,000 linear feet a day and around 5,000 linear feet on some days,” said Gonzalez. “The canal’s check structures were constructed prior to or during the paving.”
Hunter Contracting constructed all the cast-in-place structures, using nearly 6,000 linear of concrete.
John Pologar is B&W’s project manager and he is assisted by Paving Superintendent Mike Newman, Pipe Superintendent Jack Beale, and Foremen Kenny Holbrook and Josh Sipes.
“Bob Brosamer, our owner, has been building canals for more than 30 years,” said Gonzalez. “This is Pologar’s eighth canal project and Newman and Beale have decades of experience.”
Other subcontractors included DEG for the concrete structures and Harris for the rebar. Crews also installed 2,000 LF of RCP, and 3,700 LF of PVC pipe.