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PROJECTS OPERATIONS AND MAINTENANCE By Lori Ozzello O &M cements solution DEFINITELY A CHALLENGE THAT'S WHAT FIELDMAN BRUCE WILD AND SEVERAL OTHER MEMBERS OF THE OPERATIONS AND MAIN- TENANCE CREW HAD TO SAY ABOUT THEIR LATEST PROJECT. ftm THE 380 - FOOT -LONG bifurcation structure replaced an aging, prob- lematic component on the Hansen Supply Canal and Windsor Extension near the Poudre River. It features two grace- ful, arcing curves, two solar - powered drop -leaf Photo by jeDahlstrom gates and a flume section that carries water to the Windsor Extension. It's most unusual feature: a 160 -foot long side - channel spillway, a novel approach to prevent the problems that once plagued its predecessor. Supervisory Water Resource Engineer Dennis Baker spent almost a year designing the structure. One of the largest proj- ects undertaken by O &M in recent years, it involved almost everyone in the 16 -man department. "We had the expertise to do it and the guys looked at this as a challenge," Baker said. The original bifurcation structure included an 18 -foot radial gate that regulated water flow to the river and a 12 -foot radial gate that regulated flow to the extension. The larger gate was automated hydraulically and required no electrical power. Here's the way it worked: When C -BT allottees called for water, the mechanism that activated the 18 -foot gate closed it to create and hold an upstream pool. The pool was required to push water through the smaller gate and into the extension. In the early 1990s, the device became unreliable, causing spills. O &M staffers took the equipment apart, Baker said, cleaned it thoroughly and replaced parts. Still, the mechanism wasn't dependable. Next they tried an electronic controller, which helped a little, but still didn't solve the problem. Baker and then -O &M superintendent Lynn Raveling visited California's Imperial Valley to look for solutions. Operators there used electronic programmable logic controllers. The District bought one and had it installed, but the set -up came with its own drawbacks. For instance, the controller needed a back -up generator. When an electrical storm zapped its protective relays, it failed and water ran over the top of the canal. Back to square one. About two years ago, Baker met at the site with engineer- ing consultants and suggested a side - channel spillway. If the gate malfunctioned, he theorized, water would spill over a weir directly into the river. WATERNEWS APRIL 2005 "We could do it without wash- ing anything out," Baker said. His preliminary calculations indicated a 160 -to- 170 -foot weir would do. Next, he and Roger Sinden, head of the Distribution Systems, started looking for gates. "We wanted gates that were easy to Photo bynoge,s, "den operate and install," Baker said. What they found were Canadian - made, hinged, solar - powered gates. Because of their design, only a 1/2-horsepower motor is necessary to raise and lower the gates. And if power is lost, Baker said, they "go right on operat- ing with a little help" from the sun and a back -up battery. Timed to begin as the water year ended, the O &M crew first had to tear out a 400 -foot long section of the canal and widen access roads. O &M moved equipment into place and began site preparation as October wound down. Construction began in November and stretched through the winter. "The guys hung in there no matter what the weather was," Baker said. The O &M crew worked five 10 -hour days each week, Feb- ruary through March, to complete and test the project before the 2005 water year began April 1. Early in March, the final sections were poured into the forms and the gates bolted into place. The O &M guys talked about how long it would take to clean everything up before the first water would be sent through, what was left to be done, what the hardest part was. "After we poured the first floor piece, Denny (Hodgson, Working Foreman) and I thought, `We've got 29 more of these, plus the walls, "' Baker recalled. "I told Denny not to think about it, that it wouldn't get any harder than that first piece."