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Sustainable Groundwater Management Act implementation in progress

The passage of the Sustainable Groundwater Management Act (SGMA) in 2014 signified a monumental change in the way the State of California governs groundwater pumping. For the first time in history, the state passed a law to assert its power to regulate groundwater extraction. Up until 2014, the state had encouraged regions to establish groundwater extraction plans, either through agreements, or though legal action in the form of adjudications.


But now through SGMA, the state is mandating that every part of the State of California be part of a Groundwater Sustainability Agency (GSA). This requirement was met by 99% of California by the end of 2017. SGMA then requires that groundwater basins subject to critical conditions of overdraft must produce a Groundwater Sustainability Plan (GSP) by January 31, 2020. The law spells out what the plan needs to achieve and gives the local regions the authority to establish and enforce those plans. It also reserves for the state the right to review those plans and reject them if deemed inadequate.


Eleven of the 14 sub-basins in the San Joaquin Valley are considered by the state to be in a critical overdraft condition. GSA’s in these sub-basins are therefore required to produce an acceptable GSP over the next 23 months. There are 99 different GSA’s in these 11 sub-basins. There are dairy farms in many of them.


I decided to start to learn more about how things are progressing by attending the meeting of the San Joaquin Valley - Tule Sub-Basin Technical Advisory Committee this week in Tipton. There are 6 different GSA entities in the Tule Sub-basin and this meeting was made up of representatives of all of them.


They have already hired a hydrogeologist to assist in developing a groundwater model of the subbasin. The construction of this groundwater model has already begun. What a groundwater model does is estimate the groundwater levels in each part of the subbasin. It does this by identifying the various water bearing layers under the ground and estimating the inflow to those layers through percolation, and sub-surface flows and then subtracting pumping from wells and underground outflows to neighboring subbasins. These models involve thousands of calculations and many thousands of individual data points. The software to develop a groundwater model has been around quite a while and having a tool like this is very necessary to coming up with a plan to stop critical overdraft, which is required by SGMA.


At the meeting, the hydrogeologist explained where he was in the process. He has already collected a lot of data but needs more to run the model. Coordination with hydrogeologists working for the Kaweah Sub-basin to the North, the Tulare Lake Sub-basin to the West and the Kern Sub-basin to the South has begun. Water moves between these sub-basins and so a mechanism to determine those boundary flows has to be established. They hope to have some preliminary results from the model over the next few months.


The next item on the meeting agenda was a 1st draft of a formal Coordination Agreement that would be executed between the GSA’s that make up the Tule Sub-basin. There was a robust discussion about this draft. There does seem to be a strong desire to do as much together as possible, but since each of the GSA’s represent different farmers and landowners as well as different communities and towns, and each one is authorized by SGMA to develop their own GSP, there was not a consensus yet on the role the broader group should ultimately play in SGMA compliance.


My take away from the meeting was a real appreciation for the daunting task that SGMA represents to everyone, particularly in the San Joaquin Valley. Each of the 11 critically over drafted sub-basins must do exactly what the Tule Sub-basin is doing, which is hire experts and figure out how much water there is and how to equitably divide it up. There will be enormous amounts of time and money invested in this effort and very difficult decisions about how to comply will be necessary. The modeling work will reveal the extent of the overdraft and provide some guidance on how the big gap between extractions and replenishment can be bridged. But the bottom line is that change is coming and it will affect dairies as well as our farming neighbors. The line that, either you are at the table or you are on the menu is certainly likely to be true in this process as well. So, get informed and involved.




Geoff Vanden Heuvel

Director of Regulatory and Economic Affairs

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The Kern Subbasin GSAs – and there are about 17 of them – have agreed on a common approach to setting minimum thresholds.

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