California received some discomforting news last week, when the U.S. Drought Monitor classified 58 percent of the state — including Napa County — as being in exceptional drought. That officially rendering this three-year-long abnormally dry period as the most severe drought ever recorded in the state.

It’s also led to swift calls to action from lawmakers in California and in Napa County, and shifted attention to an issue with direct effects to rural homeowners and the Napa Valley’s vintners and grape growers — groundwater pumping.

At the state level, Gov. Jerry Brown’s declaration of an emergency due to the drought in January has led lawmakers in Sacramento to create a series of guidelines that, while not yet adopted, would lead to mandatory measurement and reporting of data from every water well, possible restrictions on use, and potentially enforcement through fines or legal action, according to a Napa County staff report.

The areas experiencing the worst overdraft such as San Luis Obispo County and other parts of the San Joaquin Valley would be classified as high-priority areas and would face these steps first. Napa County’s situation isn’t as dire — it’s a medium-priority area, according to the state — and county officials are calling for a phased roll out of the program, if it’s instituted.

The county has already put in place several of the aspects of the program that the state would implement, and the Napa County Board of Supervisors voted last month to voice its preference that the highest-priority areas submit to the state program first, followed by medium- to low-priority areas if local management plans don’t suffice in protecting groundwater.

But the county would have to draft a management plan for the state program, focusing on gauging use and availability of the water supplies, enforcement of laws governing groundwater usage, and potential rationing in deficient areas.

Some of this is already occurring through a voluntary well-monitoring program, as well as rationing of the amount of groundwater usage that’s allowed for vineyard and winery projects in the Napa Valley hillsides and the groundwater-deficient basin that drains Milliken, Sarco and Tulocay creeks east of the city of Napa.

Groundwater allowances for wineries and vineyards depend on where in Napa County the project is located. On the floor of the Napa Valley, that means the project is allotted one acre-foot of water — 326,000 gallons — for every acre of land.

In hillside areas such as Mount Veeder or Howell Mountain, it’s a half acre-foot for every acre; in the MST basin it’s .3 acre-feet. That’s been the standard threshold, called a water availability analysis, since 1991.

But the county Public Works Department is examining changing the analysis this summer and potentially adding a requirement that the developers conduct more extensive testing of the available groundwater in the hillsides, and determining the impact on a neighboring property’s well.

The principal architect of the water availability analysis, a retired engineer for the county named Myke Praul, defended the system he set up in the early 1990s, and said its simplicity and efficiency have served the county well over the years.

But proponents of changing the analysis, including the conservation group Mount Veeder Stewardship Council, have loudly criticized its effectiveness to the Napa County Board of Supervisors and the county Planning Commission in recent months. The rules of thumb it relies on in the hillsides can lead county planners to approve groundwater usage for projects on assumed conditions that don’t actually exist, they say.

Praul said in an interview last month that the push for additional testing would lead to a situation similar to what existed before the analysis was adopted in 1991. Many developers had to retain hydro-geologists in the process of obtaining use permits, whose expert testimony saying the project had sufficient water would be rebutted by hydro-geologists hired by opponents, who would say the opposite.

Commissioners would look to staff engineers to decide which side was right, which they weren’t qualified to do, Praul said.

“Hydro-geology is a really complex science,” Praul said. “The whole purpose (of the analysis) was to scratch a line in the sand, to establish a threshold.”

Praul’s system assumed a basic rule of thumb about rainfall and its ability to seep into an aquifer — one third would runoff into a stream, creek or river, one third would evaporate, and the final third would help refill groundwater supplies.

If the Napa Valley received 36 inches of rain in a year, Praul estimated that a foot of that would seep into the groundwater basin, which led to his one acre-foot standard on the valley floor, he said.

When developers exceed that or can’t meet other requirements, a subsequent test is needed to determine the amount of water that can be pumped in a 24-hour period. That’s only a snapshot of the well’s reliability and the storage it taps into, but gives an idea of groundwater supply’s health.

The county may expand this second test for the hillside areas, looking at how a well would be used, its planned construction, the hydro-geologic conditions in the area, and if pumping would impact nearby wells, provided the planned well was within 500 feet of a neighbor’s.

Some proponents of changing the analysis also favor adding new tests that would determine if groundwater pumping affects nearby streams or creeks, and how that relationship works.

Praul said it’s essential the county maintain a fairness factor that allocates water equally, but also wants to see the simplicity of his system preserved. The additional tests add time and costs to the use permitting process, which can rack up a hefty bill if the delays mean a winery developer has to keep doing custom crush for another season.

“You’re going to make it so complicated,” Praul said. “The costs are going to be higher. People tend to lose the simplicity of common sense.”

A third element of the analysis requires developers to create plans mitigate their impacts on groundwater supplies if they exceed the threshold, which can mean decreasing the size of the proposed winery, or going through an environmental impact report process, Praul said.

That plan then allows the county to monitor water usage, ensure other steps in the plan are being followed, and enforce it if they’re not.

“Data has to be collected and it has to be assessed on a regular basis,” Praul said. “If it includes more data, how have they managed the data in the last 23 years? If you’re going to add steps that are going to add more data, how is that going to be managed? We will revert to what was going to happen before. It’s not fun. It’s not a fun situation.”

But critics of the water availability analysis say enforcement of the water usage approvals is lax, a situation worsened by the analysis’ assumptions and equitable allotments. Harris Nussbaum, a Mount Veeder resident and member of the Stewardship Council, said he advocates the county do more.

“The facts are never checked,” Nussbaum said. “Whether they’re going to have the water is never checked. Why somebody would have to haul in a massive amount of water is never checked. The real issue has to do with what is the truth? What is the impact?”

Nussbaum said the analysis’ assumptions are flawed, and there isn’t a half acre-foot of water under every acre of land in hillside areas like Mount Veeder and along Dry Creek.

“We know from research and data and experience that what they’re saying is not true,” Nussbaum said. “They only studied the wells that people agreed to have studied. It wasn’t mandatory, it was elected. They will wake up to the fact that they really need to do something.”

Praul countered that the drought has made groundwater usage an easy target, but cautioned against making sweeping changes to a system he said has worked well. He said officials may be better served by telling winery and vineyard developers that they could jeopardize their use permit if they violate their water usage approvals.

Beyond that, policy makers have to ask — and answer— basic questions about how much development they want to see, including what kind and at what pace, and whether to suspend permitting while those queries are answered.

“There are some really simple answers out there and it doesn’t involve more regulation,” Praul said. “Do we have water for all this? If an applicant can show that, let them do it. Make them simpler, not more difficult. You don’t need more monitoring wells.”

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