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.

Respecting the environment

To lessen the environmental footprint, the pipeline design eliminated external reservoirs or tanks at the three pump stations. A 1 million gallon underground reservoir used to dampen surge pressures and enhance control flows lies beneath the Bear Canyon pump station. To keep noise whisper soft, the design replaced traditional air conditioner cooling for the five 1000-hp pump motors at each station with water cooling, accomplished with the recycled water. The pump stations also blend into their surroundings, with the station in the Audubon Wildlife Sanctuary set into a hillside and covered with a sod roof.

The design sequenced construction to avoid impacts on raptors and rare nesting birds and adjusted alignment to avoid rare plant colonies. The contractor installed pipeline at night on 2 miles of the mountainous Pine Flat Road to maintain residential access. Also during the two-year construction, the contractor issued radios to all travelers and maintained a communications system to avoid head-on collisions on the narrow winding road. Pine Flat residents gained fire protection when the contractor located fire hydrants, coordinating with the local fire district as part of the building permit process, in this remote area. This new water supply helped in extinguishing the “Geysers Fire” that burned 12,000 acres during Labor Day weekend 2004.

Heavy construction presented challenges in the heart of wine country. Bike races, triathlons, year-round tourist traffic, and seasonal harvest traffic challenged the schedule. Delays to grape trucks were limited to five minutes, and pilot cars led traffic through construction zones in tight corridors.

Throughout the project, the contractor maintained dust control to protect crops. In the mountainous area, the contractor monitored the air during excavation to verify dust control measures protected workers from naturally occurring asbestos. Also, the contractor carefully returned excavated serpentine rock containing asbestos, chromium, nickel, and lead to original locations to avoid shipping hazardous waste.

Crossing the Russian River twice without environmental impacts required microtunneling. On the south crossing, “Big Stan,” the world's largest vertical boring machine, drilled 30-foot-diameter shafts up to 100 feet deep on either side of the river. From this depth, a boring machine dug a 60-inch-diameter, 700-foot-long tunnel beneath the river. Then crews pushed 48-inch-diameter water pipeline through the casing. This double-pass technique was followed on all 15 underground crossings of creeks, roads, and environmentally sensitive areas.