Piping project aids water flow

The city is currently working to improve water flow as part of a water intertie project on Lovall Valley and Thornsberry roads. The Zone 1-2 Water Intertie Project started on Lovall Valley Road near Old Winery Road Monday, Nov. 4, with crews digging trenches.

According to Dan Takasugi, Sonoma’s Department of Public Works director and city engineer, Sonoma’s 2011 Water Master Plan showed certain water service areas had low fire flows – the amount of water needed in case of a fire – and that the East Napa Street and Thornsberry Road water tanks had “insufficient” cycling of water. “This project will remedy those problems,” Takasugi said.

The city requires single-family homes be able to provide 1,500 gallons of water a minute for two hours and all other types of construction be able to provide 2,000 gallons of water a minute for two hours, Takausgi said, noting “the water service area around Lovall Valley Road fell short of the requirement.” By connecting pipelines between Pressure Zone 1, on Lovall Valley Road near Old Winery Road, and Pressure Zone 2, on Thornsberry Road, via water interties, this project will remedy low fire flow.

Sonoma City Council awarded a contract for $424,736 to Healdsburg’s Terracon Pipelines Inc. at its Sept. 16 meeting and gave notice for the contractor to proceed on Oct. 28. The funding for this project, Taksugi said, comes from the City Water Utility Enterprise Fund.

The city will place 8-inch water pipe under the road surface, about 2,000 feet on Lovall Valley Road in Zone 1 and 300 feet on Thornsberry Road in Zone 2, Takasugi said, adding control valves and equipment will be installed to regulate the pressure and flows between the two pressure zones.

“The work includes the installation of new water mains in portions of Lovall Valley Road and Thornsberry Road connecting pressure in Zone 1 and Zone 2 to improve fire flows in portions of Zone 1, and to improve water quality from greater turnover Napa Street and Thornsberry storage tanks,” Takasugi said. The intertie project will not add any new water service connections, according to Takasugi, since the city is still operating under a water connection moratorium.

As outlined in the project plan, crews will saw-cut existing asphalt and demolish existing pavement to excavate trenches and lay new pipes, fitted with new valves to increase flow, Takasugi said. After the pipes have been laid, crews will repave sections of Thornsberry and Lovall Valley roads where trenching has occurred.

Takasugi estimates the project will take three months and expects it to be completed in mid-January 2014. But, he says, the final paving work is dependent on the weather and unfavorable conditions could cause delays. While the project is underway, there will be one-way traffic control with flaggers; so far, Takasugi says delays have only lasted a couple minutes.