Launch Slideshow

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Pipeline partnership

Pipeline partnership

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    “Big Stan”—the world's largest vertical drilling machine—drills a 30-foot-diameter shaft 100 feet deep for the 700-foot-long tunnel beneath the Russian River. Photo: CH2M Hill

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    Sensors and isolation valves at the faults will shut down the pipeline if an earthquake of magnitude 5.5 or greater occurs. Photo: CH2M Hill

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    The pipeline heads through a narrow construction corridor along the electrical company's easement, directly up the ridgeline in the environmentally sensitive Audubon Sanctuary while the road lies about a half mile away. Photo: City of Santa Rosa

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    Photo: City of Santa Rosa

    Former Santa Rosa mayor and current city councilwoman Janet Condron officially breaks ground for the pipeline in June 2000.

Handling Opposition

“We built this project through a land of NIMBYs [not in my back yard],” said Doug Smith, CH2M Hill assistant program manager. Although the pipeline passes by 1200 private properties, it only passed through a couple dozen. Still, since every alternative considered met some public opposition, the project required an extensive public relations effort. Mailings to more than 3000 people informed property owners, residents, and affected agencies. Other communication included public meetings, Web sites, and permission-based e-mail broadcasts.

Affected entities and individuals filed 14 lawsuits seeking to halt the project. Santa Rosa's environmental and construction documentation was thorough, however, so it didn't lose any of the cases and no injunctions were issued. The municipality won a number of the cases and settled others. The original plan was to construct the project by awarding three contracts in each year—2000, 2001, and 2002—completing by December 2002. However, litigation and right of way issues reduced the work underway in 2000. In 2001, four contractors were working on the project; in 2002, five. The numerous crews simultaneously working in close proximity created logistics challenges and resulted in some delays, said Carlson.

“We actually lost a year and couldn't finish until 2003. As a result, the final contract for restoration also began a year late,” said Carlson. A restoration expert performed the environmental restoration as a separate contract for all the construction.

Carlson considers the settlement with the Audubon Wildlife Sanctuary one of the positive outcomes. The designers sited the pipeline in the middle of the road, believing this was public right of way. In reality, only the surface was public, and when the Audubon Society purchased the land, it owned the underground rights. Instead of fighting the society, the city asked, “What are your concerns?” and “How can we make this a better sanctuary when we're done?”

The city agreed to share the savings by routing the pipeline through the sanctuary, rather than pursuing an alternative alignment. The Audubon alignment was the environmentally superior route and resulted in a win-win for both parties. But despite continued efforts at coordination, construction through the sanctuary resulted in greater impact than Audubon's sanctuary manager had anticipated and caused more significant delays than the city had expected.

Building to Last

“With the pipeline passing through environmentally sensitive areas, wine country tourist routes, and close to residences, we wanted to minimize dig-ups for future repairs, so one of our mantras was this pipeline needed to last beyond this generation,” said Carlson.

Both the 48-inch pipeline crossing the 30-mile valley and most of the 30-inch diameter pipeline section climbing 10 miles into the mountains are welded steel double-coated with tape and a cement mortar rock shield for durability. Two companies supplied the majority of the pipe: Pasadena, Calif.-based Ameron International Corp. supplied the 48-inch-diameter welded steel pipe from their Stockton, Calif. location, and Portland, Ore.-based Northwest Pipe Co. supplied 30-inch-diameter welded steel pipe from its local offices. To expedite construction, the low-pressure portions of the 30-inch pipe (just before the booster pump stations) are high-density polyethylene. To deal with the local corrosive soils, the pipeline has an active cathodic protection system, the effectiveness of which is continuously monitored. A fiber optic cable for system control runs along the entire alignment.

The pipeline design will also accommodate future technology. The oil and gas industry uses remote sensing vehicles dubbed “smart pigs” to monitor the interior conditions of its pipelines. Although this technology is not yet available for water pipelines or large-diameter pipeline, using large ball valves that open fully instead of standard butterfly valves ensures future access.

Extensive geologic work identified two active faults on the pipeline pathway. Sensors and isolation valves at the faults will shut down the pipeline if an earthquake of magnitude 5.5 or greater occurs. These systems are common in small piping systems carrying chemicals, but not typical for high-pressure water transmission lines, said Gary Nuss, CH2M Hill project manager.

In the mountainous area, the pipeline crosses 700- to 1000-foot-wide slide areas. Here, ball joints will allow the pipeline to expand, contract, and rotate to lessen the risk of rupture when a landslide moves through. Inclinometer sensing equipment monitors soil displacement. Inclinometers placed every 100 feet provide data points at depths from 5 to 100 feet to profile soil movement. This data would allow stresses to be anticipated so the pipeline could be realigned before a rupture, since a rupture would interrupt service, cause significant environmental damage, and jeopardize public safety.