Having flexibility in the size and design of a planned recycled water pipeline in the Coombsville area may cost Napa County an extra $650,000.
On Tuesday, Public Works Director Steve Lederer will ask the Board of Supervisors to approve that amount to cover additional costs for redesigning the 4.5-mile-long pipeline to serve a smaller volume of water, as well for more engineering work to relocate the pipeline’s pump station, which had been set to be built at Skyline Park, according to a staff report.
Lederer is requesting $696,000 total, which would be paid for by Measure A, the half-cent sales tax measure for flood control. The remaining $46,000 is to pay for Napa County’s membership dues in the North Bay Water Reuse Authority, and to cover its share of the cost of extending the pipeline from Napa State Hospital to Skyline Park, according to the report.
Of the $650,000, $260,000 would pay for the additional engineering work on the pump station, while $390,000 would pay to redesign the pipeline to a smaller size.
Both of these costs cover the county on the pipeline’s two most significant variables: where to place the pump station, and how much water — and thus how large a pipeline — it can afford.
In October, the Board of Supervisors voted to move forward with constructing the pipeline, which would run from Skyline Park through the heart of the groundwater-reliant Coombsville area, providing 1,000 to 2,000 acre-feet of recycled water to residents, vineyards and the Napa Valley Country Club from the Napa Sanitation District’s treatment plant.
The pipeline has been designed to the 2,000-acre-foot-size, but as of October the county lacked enough potential customers to afford this $16.3 million option. It does have enough customers to cover the smaller 1,000-acre-foot line, which is estimated to cost $12.3 million.
Potential users will vote in December on forming an assessment district to cover the cost of the project. They would pay over a 20-year period through annual property tax assessments.
There’s also another variable — the county has applied for another $2 million in grants from the U.S. Bureau of Reclamation. Getting that money would defray the total cost, encouraging more customers to sign up to use the pipeline.
The county was planning to build the pump station in Skyline Park after it purchased the park from the state, but negotiations over the purchase have failed due to a disagreement over price.
Thus, the county has to plan to put the pump station on the grounds of Napa State Hospital, or on a piece of private property farther east.
If the assessment is approved next month, construction on the pipeline could begin next spring.