Semitropic Water Storage District in Kern County approved paying its share of the planning and permitting cost for the delta tunnel this week. The Delta Conveyance Program is part of the State Water Project, which you can learn more about here. The next two years of planning costs $300 million of which Semitropic’s share is $2.3 million. The actual cost to the build the tunnel is currently estimated at over $16 billion. Environmental regulations in the delta have reduced the long-term expected yield of the State Water Project down to 54% of their contracted water. The tunnel would create an intake on the Sacramento River in the northern delta where fish impacts are less, and transport that water underground to the California Aqueduct pumps in the southern delta. Semitropic’s share of the firm yield of the project is relatively low, but by participating in the project, Semitropic gets access to surplus water in wet years. Semitropic has direct access to the California Aqueduct and a lot of groundwater storage capacity, so its hope is that it will be able to get more wet year water if the tunnel solves the fish problem. The commitment the Semitropic board made this week keeps them in the project. The big decision on whether or not to participate in the construction of the tunnel will be made in 2027.
In the Tule Subbasin, Pixley and Lower Tule River Groundwater Sustainability Agencies (GSAs) are working hard to get an exclusion from fees and reporting, which the State Water Board imposed when the Tule Subbasin was placed on probation last September. At that hearing, State Water Board members recognized that these two GSAs had made a lot of progress in addressing their plan deficiencies and indicated that an exclusion was possible. The State Water Board staff has been working closely with these two GSAs and wants to see evidence that the plan improvements they have made are being implemented. To that end, Pixley and Lower Tule have significantly reduced their groundwater pumping allocations and are requiring all agriculture wells to be metered by the end of 2025. The main purpose of metering is to inform the development of a subsidence management plan. Subsidence has emerged as the most serious and difficult problem to solve. It does seem like some targeted stopping of deep groundwater pumping would be a good initial step, but getting the data to identify what wells are causing the most subsidence is the challenge.
The Kaweah Subbasin also has a subsidence problem. They too are working on a subsidence management plan in collaboration with their neighboring subbasins. Kaweah’s probationary hearing was canceled in January, and it is working hard to implement its Groundwater Sustainability Plans (GSPs) and get back to Department of Water Resources (DWR) control.
The enforcement of the State Water Board’s probation on the Tulare Lake Subbasin is still on hold due to a court-issued preliminary injunction. The State Board has filed a number of appeals that are pending. Meanwhile, the Tulare Lake GSAs are making good progress on updating their GSPs, including pumping allocations, with robust stakeholder engagement in the two GSAs that were the most challenged a year ago when the State Board voted to put them in probation.
The Kings Subbasin has an approved plan and continues to make steady progress in achieving groundwater sustainability. It helps when you have access to a mighty river like the Kings.
The Madera Subbasin also has an approved plan. The undistricted part of the subbasin is covered by the Madera County GSA. The plan involves strict groundwater pumping allocations that are reduced every year. The first five years of the ramp down was a reduction of 2% per year. The ramp down rate increases to 6% per year starting at year six. This same approach also applies to the Madera County GSA portion (the undistricted area) of the Chowchilla Subbasin. Managing the reduction in access to groundwater is about to get significantly more painful.
The portion of the Chowchilla Subbasin that is in the Chowchilla Water District is talking about establishing pumping allocations, but because of its access to both Friant water and the Chowchilla River, it has a little more time. The Chowchilla Subbasin is subject to State Water Board jurisdiction. It has updated its GSP, and indications are that great progress has been made in addressing the deficiencies that were identified in its plan.
The Merced Subbasin has an approved SGMA plan. The portion of the Merced Subbasin that is undistricted is also moving ahead with developing a pumping allocation program. There is also robust stakeholder involvement in this GSA. The Merced Subbasin GSPs set minimum thresholds for 2040 that are generally HIGHER than their current water levels. What this means is that over the next 15 years, Merced’s plan is to actually elevate water levels in its subbasin by putting more water in the ground than it takes out. They have a plan and schedule for how they will accomplish this. I saw the numbers that the Merced Subbasin is reporting to DWR for the 2024 water year and so far, they are on track to meet their schedule. Having a good river and a big lake (McClure) helps. But they are rightfully very concerned about a State Water Board imposed regulation that could greatly reduce their access to the Merced River. You can learn more about this here.
The Delta Mendota Subbasin is also under State Water Board jurisdiction. There are over 20 GSAs in this subbasin, but they have pulled together and resubmitted a unified GSP to the State Water Board that they believe addresses all of their deficiencies. They too have access to significant surface water supplies but are beginning the process of developing a groundwater allocation program.
The northern part of the Valley has some groundwater challenges too. But since they have access to much larger amounts of Sierra surface water, they have more options and less pain in complying with the requirements of SGMA.
Geoff Vanden Heuvel
Director of Regulatory and Economic Affairs
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