In the past, City of Grand Junction planners believed that Grand Junction's water distribution network would expand farther than it has, resulting in several transmission water lines being oversized for present-day water demands. Faced with approximately 4,000 feet of aged 24-inch steel and ductile iron water lines that were prone to failures, the City of Grand Junction's Water Department analyzed the existing flow characteristics and determined that this particular transmission waterline did not have the water demand necessary to support such a large pipe and the water within the pipe was losing the chlorine disinfection residual because it was not being consumed fast enough. The water line needed to be reduced in size based upon the realistic service area demand. Given the option between traditional open trench installation methods and slip-lining the existing pipe alignment, trenchless methods proved to be more cost effective due to several factors that will be detailed in this paper. The City slip-lined a new 18-inch thermoplastic pipe inside the old metallic pipe. The new waterline was successfully installed in three pulls.
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