YOUNTVILLE — The operator of the Clover Flat landfill outside Calistoga faces a 5 p.m. deadline Tuesday to account for the contamination of a Napa River tributary last week – and to take steps to prevent further leaks ahead of a rainstorm expected on Friday.

A Napa County order requires Upper Valley Disposal & Recycling to meet a list of conditions by the close of business Tuesday, in the wake of a release of chemical-laced runoff from the landfill into Dutch Henry Creek. The release led Napa County to issue an advisory on Friday and warn people not to make contact with or use water from the creek, which flows into the Napa River.

Under the order from the county’s Local Enforcement Agency, an enforcement arm of CalRecycle, landfill operators must ensure that all runoff is captured before reaching the creek, map discharges that already have occurred, cover refuse with soil rather than green waste, and present a plan to prevent further runoff from the site, county Planning Director David Morrison told the Upper Valley Waste Management Agency board in a special meeting Monday at Yountville Town Hall.

Morrison called an immediate stoppage of pickup services after the deadline unlikely. “The primary goal is compliance, not closure and not a contingency,” he told the Upper Valley agency board.

Agency directors, who include two Napa County supervisors and council members from Calistoga, St. Helena and Yountville, warned the landfill’s leadership for putting water quality at risk, but also imperiling trash pickup services across the Upvalley by risking a full shutdown of Clover Flat. The facility stopped accepting private drop-offs on Saturday after the county issued its notice, but continues to accept deliveries from local cities.

“This is not something that’s been incurred overnight; this has been going on for a very long time,” Calistoga Mayor Chris Canning told the landfill’s general manager Bryce Howard, referring to a series of incidents that included several fires at the facility in 2018. “There’s not a lot of credibility here now. I don’t have faith that your organization has the ability to correct this problem. This is just one mess after another, and another, and another.”

A county inspection of Clover Flat last week revealed erosion on one of the landfill’s trash-holding cells and a 4-foot gash in its clay lining, as well as completely filled tanks of leached-out liquids and non-functioning sump pumps, according to Morrison. The discoveries led to the county issuing its notice, which he said did not indicate “an immediate or dire public health problem” but was made “out of an abundance of caution.”

Early studies indicate the runoff from landfill to creek topped out at a half-gallon per minute before being diluted by creek water on its path to the Napa River, said Julian Isham, a Concord hydrogeologist working with Upper Valley Disposal.

Howard, the Clover Flat manager, told the Upper Valley agency that repair work over the past week has stopped seepage into Dutch Henry Creek, and that work will continue on improving runoff containment amid forecasts of more rain in the coming days. The National Weather Service forecasts rain in the Napa Valley on Friday, with showers possible in the days before and after.

A package of permanent fixes likely would cost about $1 million and include improvements to storage tanks, pipes, pumps and pond collection, Howard said.

Although the collection ban at Clover Flat affects only private drop-offs, county and city leaders with the Upper Valley agency were concerned enough to question landfill operators about how to handle trash hauling should the facility be barred from accepting municipal waste as well.

Howard said staff has been in talks with the Devlin Road facility south of Napa to accept deliveries in case its own landfill should become unavailable. In that event, Clover Flat could become a transfer station for waste to be trucked farther south, a step that would require waiting on a permit from the Local Enforcement Agency – up to five days to ship up to 15 tons a day or 30 days to ship 100 tons, said civil engineer Evan Edgar of Sacramento.

Upper Valley Disposal would notify its customers by phone of any resulting service changes, according to Howard.

Even if the latest landfill incident is contained without a crisis, Canning, the Calistoga mayor, speculated the extent of the troubles at Clover Flat may require local governments to find a new and better-equipped operator in the long run.

“We may have to look at the possibility that the industry has outgrown this company’s ability to do it,” he said.

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City of Napa/Town of Yountville Reporter

Howard Yune covers the city of Napa and the town of Yountville. He has been a reporter and photographer for the Register since 2011, and previously wrote for the Marysville Appeal-Democrat, Anaheim Bulletin and Coos Bay (Oregon) World.