Cartridge Method Solves HDD Challenge Across Hunting Bayou (Source: Trenchless Technology)

By Christine Kirby

One of Houston’s major water transmission mains is a 42-inch line that begins at the East Water Purification Plant and continues north and west to provide water to a large distribution area in the northeast part of the City. Spanning nearly eight miles, the pre-stressed concrete cylinder pipe along Federal Rd., IH-10 East Freeway, and Loop 610 was constructed in the late 1960s and early 1970s. This 42-inch main has a history of leakage and needs repairs.

The City of Houston recently detected an active leak on this aging 42-inch line within the project limits. Part of this line, which crosses Hunting Bayou above-grade, had been submerged in recent flooding and needed to be replaced. Two isolation valves on the 42-inch line also needed to be replaced. To perform this repair work, a long-term shutdown was desperately needed.  Shutdown was not a possibility, because isolating the 42-inch would put these eight customers out of service.

Lockwood, Andrews & Newnam, Inc. (LAN), a national planning, engineering and program management firm, has served as the City of Houston’s technical advisor for its Surface Water Transmission Program (SWTP) for more than three decades. The City asked LAN to develop a solution to repair the 42-inch line without disrupting service to the eight customers.

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