The Nevada Irrigation District is planning an emergency repair project after leaks were detected in a large 90-year-old pipeline that runs through a tunnel beneath the rockfill dam at Bowman Reservoir.
In a Wednesday report to the NID Board of Directors, General Manager Rem Scherzinger said the district is moving forward with plans to reactivate a bypass to supply water while permanent repairs are completed.
“We don’t want to lose our operational window,” Scherzinger said at the meeting.
He said the district anticipates having the bypass in operation prior to this year’s irrigation season, which begins April 15, and when seasonal demand for water begins to rise. He said the permanent fix is expected to be complete this summer.
The fix will entail the replacement of a large segment of the pipe that will need to be sealed, Scherzinger said.
District officials are placing high priority on the repairs because Bowman is at the center of NID’s Upper Division water storage system. Water from several mountain reservoirs runs through Bowman and the Bowman-Spaulding Canal to PG&E’s Lake Spaulding, where it is routed to NID customers in Nevada and Placer counties.
Bowman is located at the 5,600-foot elevation on the western slope of the Sierra. Officials said this year’s light snowpack and early runoff should benefit the district in providing the temporary supply and making the permanent fix.
NID associate engineer Keane Sommers, who is heading the repair effort, said the leak was first detected by NID’s resident laketender at Bowman. Inspections showed cracks in the old riveted 48-inch diameter steel pipe that dates to the dam’s construction in 1925-26. Damage to a butterfly valve was also found.
Sommers said the damage is confined to a 20-foot section of the pipeline just above its outlet. He said a new section of pipe and a new outlet valve house are being planned.
Meanwhile, to keep water flowing, the district plans to spill water over another dam at Bowman, the South Arch Dam, and divert this water into the Bowman-Spaulding Canal.
Sommers said an inlet taken out of service in this area in the 1980s to divert water when the nearby powerhouse was being built, would be uncovered and reactivated for the temporary supply.
District officials have been meeting with a specialty contractor, who will be expected to quickly mobilize and complete the repairs as soon as possible. Approval of an emergency contract is expected soon.
The board also approved about $600,000 in expenditures to paint two water storage tanks.
River City Painting, a company based in Sacramento, won the contract to paint both tanks, one near Osborne Hill in proximity to Grass Valley and the other near Lake Wildwood.
The Lake Wildwood project will cost about $265,000 and protect some exposed steel on the surface of the tank, said Brian Powell, NID maintenance manager.
Money from the Pipeline Replacement Fund will be used to complete the project, Powell said.
The Osborne Hill tank will cost $330,000 to repaint, and the project is necessary to halt significant corrosion to the tank’s integral steel. The bids for the project were put out March 5, and in both instances, the low bid was accepted.
The board further approved the attempt to procure a $870,000 grant to install a boat ramp at the Woodcamp Boat Ramp area of the Jackson Meadows Reservoir.
The grant, if awarded, would be utilized toward the construction of a new boat ramp, a boarding float, a rest room and a parking area, said Peggy Davidson, recreation manager.
The grant is available through the California Department of Boating and Waterways.
“I’ve been there, and that area could really use a boat ramp,” said Jim Bachman, president of the NID board.
All decisions made during the meeting were unanimous.
To contact Staff Writer Matthew Renda, email firstname.lastname@example.org or call 530-477-4239.
Inspections showed cracks in the old riveted 48-inch diameter steel pipe that dates to the (Bowman Reservoir) dam’s construction in 1925-26.