California says it might raise its alert level for monitoring Napa Valley groundwater to make certain local wells keep supplying water, although what — if anything — this means for the county’s current water policies is unclear.

The state proposes to reclassify the Napa Valley subbasin from “medium” to “high” priority. But since it requires communities in either category to take the same steps to avoid sucking aquifers dry, the proposal may or may not have consequences.

“I think at this point, everything is open to interpretation and requires additional investigation as to what DWR is trying to accomplish,” County Public Works Director Steven Lederer said.

After several years of study, Napa County had concluded that the subbasin is nearly full and is used in a sustainable way, with a few problem locations. Wineries, vineyards and residences in the heart of wine country depend on well water.

The county submitted its studies to the state Department of Water Resources a year-and-a-half ago. It wants to convince the state it is already a good steward of groundwater and doesn’t allow more water be withdrawn than is recharged.

Lederer said county officials are trying to meet with Department of Water Resources officials to learn more about the reprioritization proposal, which was released May 18.

County resident Mike Hackett, co-author of the Measure C watershed initiative on the June 5 ballot, said the county clearly has groundwater problem areas, such as the Petra Drive area east of the city of Napa. He said the state’s proposal could be significant.

“Obviously, I would be the first to admit, it’s a draft at this point,” Hackett said. “We don’t want to go off half-cocked. But I think it’s a big story.”

Resident Gary Margadant has long followed and spoken out on local groundwater issues. He is among those who want the county to go a step further and form a groundwater sustainability agency that could have various community partners.

“That’s going to make it a little more transparent to everyone around here,” he said.

The Department of Water Resources ranks 517 water basins and subbasins statewide as required by the state’s 2014 Sustainable Groundwater Management Act. It is proposing to rerank about 10 percent of basins – some higher, some lower—in an effort to keep wells from running dry, an agency report said.

“This prioritization is critical to this work,” agency Director Karla Nemeth said in a press release. “We must plan ahead so this vital resource is available for California today and in years to come.”

The agency ranks groundwater basins on a scale of zero to 42, looking at such factors as population, population growth, groundwater volume and total percent of water supplied by groundwater. A basin with a score above 21 is considered a “high” priority.

The Department of Water Resources in 2014 gave the Napa Valley subbasin a score of 20.8 for a “medium” priority ranking. The proposed 2018 score is 24 – far lower than the 42 scores among San Joaquin Valley groundwater basins, but still enough to quality as “high” priority.

A look at the data shows the Napa Valley subbasin in 2018 received higher scores from the state for population growth, total wells and impacts such as salt water intrusion. But it is difficult to determine why the scores are higher.

Officials with the Department of Water Resources could not be reached Wednesday to say why the Napa Valley subbasin ranking is proposed to be changed. An agency report listed possible reason for changes in general, such as new data.

One other change could be coming to the Napa County groundwater regime. The state proposes to change the ranking for the Napa-Sonoma Lowlands subbasin from a “very low” ranking to “medium.” That would trigger the need for studies and possibly forming a groundwater sustainability agency for this area.

The Napa-Sonoma Lowlands subbasin includes the rural Carneros region in southern Napa County and extends southward through the Napa-Sonoma marshes to Vallejo in Solano County.

“People down there have always had water problems,” Margadant said. “All you have to do is look at the Carneros Inn down there.”

The Caneros Inn, now called the Carneros Resort & Spa, is supposed to rely on well water, but has trucked water in from the city of Napa to supplement poor groundwater supplies. It is now looking at piping water from the city. The City Council in March voted to support the plan.

Go to https://bit.ly/2x3YRBu to see the state’s groundwater proposals and to make comments. The comment period is through July 18.

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Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He has worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield.