Water Flows Uphill in Colorado: Rehabilitation of 54-inch Irrigation Siphon

摘要

This project consisted of a 54-inch steel siphon pipe which is used to convey Colorado River water for the Orchard Mesa Irrigation District near Palisade, CO. Prior to any repair, this section of pipe was leaking like a sieve and the delaminating liner was impeding the flow through the siphon. Due to the steep slopes and limited staging at each access point around the siphon, trenchless technology was the best and most economical repair solution.The repair started by removing two partially delaminated coatings and sandblasting to a near white metal finish. The 0.25-inch thick steel pipe was severely corroded, and the repaired stretch of pipe had numerous leaks that were sealed with a combination of urethane injection, hydrophilic grout, and welded steel patches. Once all existing coatings were removed and leaks were sealed a single layer of Glass Fiber Reinforced Polymer (GFRP) was installed to further seal the leaks and act as a dielectric barrier for areas in which Carbon Fiber Reinforced Polymer (CFRP) was to be installed. Within the 315-foot total repair region, 156-feet of pipe had been damaged by the impact of a landslide, inducing a slight ovality within the pipe. The damaged area was strengthened by installing a single layer of CFRP which provided the equivalent capacity of 3/16-inch Grade 36 steel.The winter weather provided for a challenging project, but two weeks after this project was complete, the siphon was back in service delivering water to numerous orchards in the surrounding area.