[caption id="attachment_92842" align="aligncenter" width="500"] Growers in the groundwater-poor Coombsville appellation of Napa Valley can benefit from a recycled-water pipeline project set to start pumping next year. (credit: Coombsville Vintners & Growers)[/caption]
NAPA -- Construction on a long-anticipated five-mile pipeline designed to pump high-quality recycled irrigation water to the Milliken-Sarco-Tulocay, or MST, area east of Napa is scheduled to begin in the coming weeks.
The Napa Sanitation District Board awarded the $7.6 million pipeline construction contract to Sanco Pipelines of Campbell and a $2.4 million contract to build a booster pump station to GSE Construction of Livermore.
When completed in 2015, the pipeline is expected to initially deliver up to 700 acre-feet, or 228 million gallons, of recycled water during high-demand summer months. But the pipeline will be large enough to carry up to 2,000 acre-feet, or 651 million gallons, as more recycled water becomes available from the district and more property owners sign up to use recycled water on landscaping, vineyards and other uses, according to the county of Napa.
Half the recycled water set to flow initially has been subscribed to by water customers along the route, according to the district. A target market for the water are vineyards in the MST area. One acre-foot of water can irrigate about three acres of vineyards a year.
Construction will primarily be in roadways outside Napa.
"This is great news for the MST area," said Keith Caldwell, Napa County Supervisor for the District 5, which includes that area. "The groundwater aquifer there is overdrafted by about 2,000 acre-feet per year, and the day this project is put into service, it will be able to deliver enough water to offset up to 35 percent of that overdraft. That percentage will only grow as more people opt in to use the water."
The district is working with the county on building the pipeline and expanding use of recycled water, according to Jill Techel, Napa mayor and chairwoman of the district board.
"Especially in this time of drought, it is important to recover and reuse the valuable water resources we have available to us," Ms. Techel said. "This is a great example of what can be accomplished with residents and local governments working together to solve a common problem."
The new section of pipeline for recycled water will run from the northwest corner of Skyline Park on Imola Avenue to the end of Third Avenue, at its intersection with Hagen Road and adjacent to Napa Valley Country Club, one of the pipeline's primary customers.
A booster pump station will be built on Napa State Hospital grounds, allowing water pressure to remain high enough to reach higher-elevation locations toward the end of the pipeline.
Federal grants and a low-interest -- 1 percent -- State Revolving Fund loan of $10 million from the San Francisco Bay Regional Water Quality Control Board are projected to pay the total cost, estimated to be $13.3 million.
Project staff have applied for additional state grants earmarked for drought relief. The water board loan will be repaid over 20 years by the users of the recycled water, who will pay a special Community Facilities District tax on their property tax bills.
"Our grant and loan efforts have been greatly helped by our membership in the North Bay Water Reuse Authority," Mr. Caldwell said. "The regional approach to using recycled water gave weight to our applications."