By Lisa McEwen, SJV Water
Though some valley groundwater managers say new state guidelines “move the goal posts” on subsidence, state regulators gave fair warning of what was coming.
At a September workshop Deputy Director of the Department of Water Resources Paul Gosselin told attendees the new guidelines would require hard commitments and detailed action plans to stop the rapid sinking that has damaged canals and sunk such large sections of the San Joaquin Valley, the resulting “bowl” can be seen from space.
“We are going to get everyone in the room to put their cards on the table,” Gosselin promised during the workshop in Delano Sept. 10.
The guidelines, released by the Department of Water Resources in January, outline how agencies should manage aquifers to avoid further subsidence, or land sinking from excessive groundwater pumping.
DWR staffers will begin working with areas on how to implement the guidelines, according to a spokeswoman.
Eroding public trust
The main concern for water managers is a section in the guidelines that deals with the concept of “critical head.”
Critical head, as defined in the guidelines, is the groundwater level that needs to be maintained in fine-grained, or clay, soils to prevent “permanent compaction” of the substrata.
Groundwater agencies must determine what that level needs to be based on soil types and then establish actions to prevent groundwater from dropping below those minimum thresholds.
That could mean further slashing farmers’ pumping allocations.
“That definitely erodes public trust. It’s a potentially heavy lift and feels like moving the goal post,” Stephanie Anagnoson, manager of the Madera County Groundwater Sustainability Agency (GSA), wrote in an email.
Adhering to the critical head guidelines could also be expensive and time consuming.
“In terms of critical head, my understanding is that we would need to do a considerable amount of modeling to see the potential ways that we might need to adjust (groundwater sustainability plans) in Madera, Chowchilla or Delta-Mendota,” Anagnoson wrote. “What is challenging for us is that we may need to amend GSPs based on the modeling, without grant funding, and then ask our growers potentially for additional adjustments to allocations.”
Late in the game
Amer Hussain, who manages four of the five GSAs in the Tulare Lake subbasin, wished the guidelines had been rolled out when the Sustainable Groundwater Management Act (SGMA) was passed in 2014. SGMA requires local agencies to bring aquifers into balance by 2040. Balance includes ceasing negative effects from over pumping, such as subsidence.
“It does feel like the state is moving the goal posts when it comes to subsidence,” Hussain said in a phone interview. “SGMA has been around for 10 years and we are just now getting a subsidence document. We have been pushing the state to get this information out. We would have had the opportunity to collect this data if the state had had more discussions with GSAs and everyone else at the beginning of this process.”
The Tulare Lake subbasin, which covers most of Kings County, and neighboring Tule subbasin, which covers the southern half of Tulare County’s flatlands, are both also facing sanctions under probation.
The Water Resources Control Board placed both on probation in 2024 for lacking groundwater plans that adequately dealt with subsidence, among other things. Probation requires farmers to meter and register wells at $300 each and pay the state $20 per acre foot pumped.
Significant damage
Pumping has been so furious in both regions it has sunk a huge swath of land, known as the “Corcoran bowl,” that can be seen from space and has required a miles-long section of the Friant-Kern Canal to be rebuilt at a cost of hundreds of millions of dollars.
Hussain said managers in Tulare Lake had already been rewriting their groundwater plans to better address subsidence and get out of probation when the new guidelines came out.
He said managers didn’t think the new guidelines applied to the subbasin’s quest to exit probation, but state regulators felt otherwise. Now he’s trying to understand exactly what’s required.
“Is it a complete compliance, or an initial evaluation with a commitment to do more work at a later date?”
But DWR’s Gosselin seems to have already answered that question at the Sept. 10 workshop saying: “The message is we know this is going to be difficult but we are going to expect some pretty good action early on.”
Hussain said he is meeting with state regulators March 9 to get further clarification.
And, like Anagnoson, Hussain is concerned with how farmers will react.
“We are trying to understand how these guidelines might further limit allocations where we have subsidence,” he said. “The frustrations I hear most from growers is ‘What can I do about it? I bought this land, is there anything I can do, or am I going to keep sinking?’ They also want to know why the amount of sinking is different for them than in other (areas).”
Managing subsidence
Other GSA managers are taking the critical head requirements in stride.
In the Tule subbasin, Pixley and Tule River GSA manager Eric Limas said a critical head analysis is already underway.
“We adopted a subsidence management plan in the summer of 2024 before the (guidelines) came out,” Limas wrote in an e-mail.
Along with a critical head analysis, the GSA is gathering data through a mandatory well registry, which launched more than a year ago.
“It is important to have known well locations and construction data to properly analyze subsidence,” he said.
The Greater Kaweah GSA in northern Tulare County, likewise approved a mandatory well registration program in February. The Kaweah subbasin avoided probation, in part, for its management plan allowing for zero subsidence.
“There is no way we can manage subsidence without (well) information,” said Kings County Water District manager Dennis Mills at Greater Kaweah’s January technical advisory committee meeting.
Pleasant Valley subbasin, the latest region to be recommended for probation, is revising its groundwater plan with critical head in mind.
“The water level minimum thresholds are set at the recent historic low. The concept of not allowing water levels to continue to decline beyond where they have already been means we should not get additional active subsidence,” said Anona Dutton, chief executive officer of consulting firm EKI at Pleasant Valley’s February board meeting.
But Hussain thinks the focus on rewriting planning documents is misguided at this stage.
“I think we need to move away from being focused on the planning documents and focus on implementation,” he said. “If we do that, we can slow down and minimize some of the impacts we are seeing.”
