On May 18, 2026, San Joaquin County issued a draft environmental impact report (DEIR) to support water right application 29835. The application seeks to divert up to 158,000 acre-feet of water per year from the Mokelumne River. The stated purpose of the project is conjunctive use. Conjunctive use refers to coordinated management of surface water and groundwater in an area.
In the DEIR, San Joaquin County branded the application as the Mokelumne Integrated Conjunctive Use Program (MICUP). The Project as now proposed would be the fifth revision of water right application 29835. The Mokelumne Water and Power Authority, an entity that no longer exists, first filed the application in 1990. The California Sportfishing Protection Alliance (CSPA) protested the application in 1996.
San Joaquin County’s Proposed Project
The Project analyzed in the DEIR would allow up to 110,000 acre-feet per year of direct diversion from the Mokelumne River. It would divert water for groundwater recharge or “in-lieu recharge.” In-lieu recharge in this case means diverting surface water to irrigate crops that would otherwise be irrigated with groundwater.
The Project would also allow diversion of up to 48,000 acre-feet of water per year to storage in East Bay Municipal Water District’s (EBMUD) Pardee Reservoir or Camanche Reservoir. The Project would deliver stored water for recharge or in-lieu recharge, rediverted either from the lower Mokelumne River or from new turnouts along EBMUD’s Mokelumne Pipeline. Here, “rediverted” means water originally diverted at one place and later diverted again at another place.
The season of use for direct diversion would be December 1 through June 30. The season of use for water rediverted from storage would be July 1 through October 31.
CSPA’s Objections to the Project as Proposed
The DEIR analyzes only two alternatives, No Project, and the Proposed Project. The Proposed Project assumes that all unallocated water in the Mokelumne River is available for diversion by the Project, up to the limits in the Application. The Proposed Project defines unallocated water as water that is not:
- Needed for water users with prior water rights
- Instream flow required under EBMUD’s Joint Settlement Agreement (JSA) incorporated into EBMUD’s water right and
- Water EBMUD has committed under the proposed Mokelumne Voluntary Agreement in the Bay-Delta Plan update process.
By far, CSPA’s greatest concern with the Proposed Project is the fact that it considers water to be available as long as it is unallocated for existing users, Joint Settlement Agreement minimum flows, and the Mokelumne Voluntary Agreement.
Some of CSPA’s History with Application 29835
In 2011, CSPA engaged with San Joaquin County Public Works on the water availability analysis for application 29835. CSPA specifically objected to the proposal to consider all unallocated flows above the minimum required flow to be available for appropriation.
From 2013 to 2015, CSPA engaged with the County and others in the MokeWISE stakeholder process for the greater Mokelumne River watershed. See https://www.mokewise.org/ and https://www.mokewise.org/docs/MokeWISE%20Program%20Methodology_20May14.pdf.
Through this process, CSPA sought to evaluate options for alternative flow requirements for application 29835. San Joaquin County did not substantively engage on this issue.
In 2024, CSPA commented orally and submitted written scoping comments on the Notice of Preparation of a DEIR for application 29835. The written scoping comments contained an appendix that CSPA wrote in 2017. The appendix describes a series of conceptual approaches to flow setting for water rights for groundwater recharge. After submitting its 2024 scoping comments, CSPA communicated to the County several recommendations for alternative flow requirements that might apply to application 29835.
CSPA Comments on the DEIR
On May 26, 2026, CSPA presented via Zoom initial comments on the DEIR. The script of those comments is here. The concluding summary of the comments stated:
“The overarching concern here is the effort of this project to allow diversion of all flows in the Mokelumne River that are in excess of the existing minimum requirements. CSPA will not be alone in opposing such an effort. The absence of alternative flow requirements in the DEIR, in my opinion, makes it deficient under CEQA. Equally important, if the County continues an all-or-nothing strategy on bypass flow requirements, it portends a protracted fight at the Water Board.
As we have for 15 years, CSPA stands ready to work with the County to develop bypass flow requirements for this water right application that could work for everybody.”
Next Steps
San Joaquin County will respond to comments and issue a subsequent or final EIR for the MICUP Project, likely later this year. Hopefully, the next EIR will analyze alternative flow requirements for the proposed project.
The State Water Board will issue a notice of the revised application 29835. The Board will accept protests of the revised application. A protest resolution period will offer protestants and the County an opportunity to jointly develop alternative flow requirements. It will also allow the opportunity to resolve additional issues with revised application 29835. If any protests remain unresolved, the Administrative Hearings Office of the Board will conduct an evidentiary hearing on the application.
The Bigger Picture
Interest in new diversions that feature or emphasize groundwater recharge has increased exponentially over the past five years. For previous discussion, see https://calsport.org/groundwater-gold-rush/. The minimum flows proposed in the DEIR for application 29835 are disappointing. But there are some upsides to San Joaquin County’s approach.
First, the County is operating within the water rights system. Second, the County is doing CEQA. These factors are not always a given.
Many diversions to groundwater take place within the context of “temporary” water rights granted by the State Water Board. Some diversions to groundwater are allowed without any water right, provided they are diversions during “floodflows.”
Assembly Bill 2026, currently pending before the state legislature, would broaden the use of both temporary water rights and diversion of floodflows. It would make default flow requirements for temporary water rights in the Sacramento Valley much less restrictive than before. It would greatly expand the definition of “floodflows.” AB 2026 would also eliminate the requirement for environmental analysis under CEQA, both for temporary water rights and for diversion of floodflows.
Setting watershed-specific flow requirements for diversions to groundwater is a better answer. Dealing with applications for diversions to groundwater in the context of actual water rights, and with environmental analysis under CEQA, is basic. Application 29835 at least offers these opportunities.
In a presentation to the State Water Board on January 23, 2025, Dr. Chandra Chilmakuri, Assistant General Manager of the State Water Contractors, presented an analysis that showed that Delta outflow in the months of January-June was greater than or equal to 42,800 cubic feet per second about 36% of the time. It is worth evaluating that threshold as a simple global Delta outflow requirement for groundwater or other high-flow diversions, to overlay onto watershed-specific criteria.
In sum, San Joaquin’s water right application offers opportunities as well as threats. Hopefully, San Joaquin County will see the wisdom of developing a project that is cost-effective with less aspirational diversion requirements.