PG&E Helicopters in Pipe Segments of South Yuba Pipe for Repairs; Spaulding 2 Repairs

By Paul Moreno

Pipe segments for the South Yuba Pipe were placed by a heavy-lift helicopter last week as PG&E works to replace a 240-foot section of pipe taken out by a winter rockslide in Nevada County. Now that the pipe is set, crews will spend the next few weeks welding and installing collars to ready the pipe for water.

(See a video of a helicopter delivering a pipeline segment.)

A Type 1 heavy-lift helicopter capable of lifting over 17,000 pounds had been reserved for PG&E in mid-July but was diverted to support critical firefighting needs as a result of the increased national fire activity. Fortunately, PG&E was able to reserve another Type 1 helicopter for early August.

The South Yuba Pipe is one of two ways PG&E conveys water from Lake Spaulding to the Nevada Irrigation District's South Yuba Canal. The other is from a diversion on the Drum Canal to the South Yuba Canal. About 60 cubic feet per second (cfs) of water has been flowing into the South Yuba Canal from a diversion on the Drum Canal since PG&E repaired the Spaulding 1 Powerhouse in July.

PG&E anticipates the South Yuba Pipe will be repaired in mid-September. In the meantime, water agencies continue to request customers and community conserve water during the ongoing repairs.

During start-up testing operations of PG&E's Spaulding 2 powerhouse, the generator sustained mechanical damage that will require additional repairs extending the return to service date beyond the return to service of the South Yuba Pipe. PG&E is in the process of developing a repair plan and schedule and will continue to coordinate with NID & PCWA.

Fortunately, repairs to the Spaulding 1 powerhouse's first of two water discharge liner in July means that a total of about 450 cfs of water is flowing in the Drum Canal. A portion of these flows, approximately 60 CFS, have been diverted into the South Yuba Canal below the pipe repair supplying NID's Scotts Flat Reservoir. Once the Spaulding 2 powerhouse is back in service, flows as much as 100 cfs or more could go into the South Yuba Canal restoring then full operational flow. The additional water into the South Yuba Pipe will allow all flows from Spaulding 1 powerhouse to remain in the Drum Canal.

PG&E has communicated the initial event at Spaulding 2 and finding with PCWA and NID and is coordinating the repair plans and schedules to minimize the impacts to water deliveries.

PG&E is working with water agencies to develop a schedule to repair the second water discharge liner at Spaulding 1 powerhouse as it will require an outage on Spaulding 1 powerhouse and limit outflow from Lake Spaulding. When complete, as much as 750 cfs will be able to move through the powerhouse.

The Spaulding 2 powerhouse empties into the South Yuba Pipe, which connects to NID's South Yuba Canal and flows to NID's Scotts Flat Reservoir. The Spaulding 1 powerhouse empties into the Drum Canal, which feeds into NID's Rollins Reservoir. PCWA also draws water from Rollins Reservoir.

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