The Kern Fan Groundwater Storage Project aims to create a regional water bank in the Kern Fan area, capable of recharging and storing up to 100,000 acre-feet of unallocated Article 21 water from the State Water Project. Operated by Irvine Ranch Water District (IRWD) and Rosedale-Rio Bravo Water Storage District (Rosedale), the project prioritizes water storage during wet years.
Proposition 1 of 2014 dedicated $2.7 billion for investments in water storage projects, which the California Water Commission administers through the Water Storage Investment Program (WSIP). The Kern Fan Project is one of the five remaining projects that must complete the remaining requirements to receive their funding award. Those requirements include final permits, environmental documents, contracts for the administration of public benefits, and commitments for the remaining project costs.
At the July meeting of the California Water Commission, Fiona Nye, Project Manager and Director of Water Resources for Irvine Ranch Water District; and Dan Bartel, General Manager with the Groundwater Banking Joint Powers Authority, the project proponent for the Kern Fan Groundwater Storage Project, updated the Commission on their progress toward completing the Water Storage Investment Program requirements.
PROJECT PROPONENTS
Rosedale Rio Bravo, established in 1959, is an independent special district in Kern County focused on groundwater recharge to address overdraft conditions. It manages over 470,000 acre-feet of stored water through a conjunctive use program.
Irvine Ranch Water District (IRWD) serves 20% of Orange County with potable and recycled water, as well as handling wastewater and urban runoff treatment. In 2007, IRWD launched a water banking program in Kern County, partnering with Rosedale to manage projects and enhance water supply reliability.
Building on this successful collaboration, IRWD and Rosedale created the Groundwater Banking JPA to develop the Kern Fan Groundwater Storage Project.
THE KERN FAN GROUNDWATER STORAGE PROJECT
The Kern Fan Groundwater Storage Project is a groundwater banking project that will store 100,000 acre-feet of groundwater storage in the Kern Fan area. It is designed to capture surplus water, such as Article 21 water, during exceptionally wet years, store it, and make it available for use during dry periods.
Article 21 water is excess supply provided to State Water Project contractors during wet years when project facilities lack storage capacity. The project’s operations are coordinated through the Kern County Water Agency, a State Water Project contractor, with Rosedale as a member agency, and the Dudley Ridge Water Storage District in Kings County, where IRWD owns property and has access to State Water Project supplies.
To support the project, a conveyance system will be built to transfer up to 450 cubic feet per second of water from the California Aqueduct to the recharge basins. The project includes the construction of 1,300 acres of new recharge basins, capable of recharging approximately 100,000 acre-feet of water annually. Additionally, up to 12 recovery wells will be installed to extract stored water when needed.
The map shows the location of the project. Existing infrastructure allows the project to bring in federal and state supplies via the Cross Valley Canal. The pink area is the Rosedale service area. The blue shaded areas are existing banking projects that IRWD and Rosedale already operate. The green and red areas represent the facilities under construction, with some already complete. Conveyance from the California Aqueduct is needed to get the water to the new facilities.
PUBLIC BENEFITS
The Kern Fan Groundwater Storage Project is one of three Water Storage Investment Program initiatives designed to support pulse flow benefits for the Feather River below Oroville Dam. The project commits to providing 18,000 acre-feet per pulse flow, totaling 125,000 acre-feet over 50 years.
Pulse flows are facilitated through a collaborative exchange process with State Water Project (SWP) contractors and groundwater banks. When the Department of Fish and Wildlife requests a pulse flow, SWP contractors receive their water allocation from groundwater banks instead of Lake Oroville. This allows water to be released from Lake Oroville into the Feather River, delivering ecological benefits such as improved water quality and enhanced salmon migration. These controlled reservoir releases mimic natural flow patterns, creating healthier habitats and migratory pathways for native fish species. (For more on how the pulse flow projects work, click here.)
“Based on updated modeling using Cal Sim 3, we estimate that over the life of the project, we’ll be able to make about 140,000 acre feet of water available for pulse flows to benefit those species,” said Ms. Nye. “When we recharge water, it’s on the surface for a while until it percolates, so we also provide the benefit of creating these incidental wetlands every time we recharge. Our project is located in a very critical place on the Pacific Flyway, and so these incidental wetlands create habitat for waterfowl, shorebirds, and raptors. So that is a significant local ecosystem benefit that we’re also able to provide.”
The project will also provide water for emergency response in the event of an extended drought or Delta levee failure. It is estimated that 72,000 acre-feet could be available over the lifetime of the project for that purpose.
PROJECT DEVELOPMENT
In the first year, twelve detailed technical memos were developed to outline the project design. These memos have significantly streamlined the design process, providing consultants with a clear foundation to work from.
The JPA board was willing to invest in building some recharge facilities ahead of the conveyance system’s completion. Once the conveyance is operational, they plan to acquire additional property and construct the remaining facilities.
Over the past two years, two recharge projects spanning 350 acres have been completed. These efforts included the construction of six miles of levees and the placement of 200,000 cubic yards of compacted earth, laying the groundwork for the project’s future expansion.
“They are really small dams,” said Dan Bartel. “We don’t just take dirt with tractors and push up piles. These are engineered, geo tech designed levees because our neighbors are farmers, homes, railroads, highways – you name it. We’re not in an isolated geographical area. We are in the community. So these are highly engineered facilities.”
Control structures are built using a prefabricated design and assembled by a local contractor. The components are fabricated off-site in the contractor’s yard, delivered in three sections, and assembled on-site in the field.
Mr. Bartel noted the project is already accruing benefits. “In 2023, we did a pilot project. Water was available. Following the governor’s directive, we created pilot ponds on approximately 150 acres. We had wetlands in 2023, and we have already recharged about 8000 acre-feet under the project. The long-term benefits of what we’ve completed are about 52,000 acre feet. So we’re not only already constructing; we’re already operating.”
Construction of four recovery wells began in July 2025, with 1.7 miles of pipeline already completed. Additional project elements are currently in the design phase and are expected to be opened for bidding later this year.
In collaboration with the contractor for the conveyance system, two alternatives have been identified along the same route. One option is a fully independent system separate from the Cross Valley Canal, while the other proposes a joint-use facility that integrates with and enhances the Cross Valley Canal, maximizing efficiency and shared resources.
For the California Aqueduct turnout, the necessary approvals have been secured to begin designing modifications to the existing turnout from the Cross Valley Canal. These alterations significantly reduce costs by utilizing the existing turnout, which has sufficient capacity. However, conveyance limitations will be addressed by constructing dual side-by-side canals to fully leverage the turnout’s capacity.
“It’s just a matter of working through the process with the Cross Valley Canal participants and the Kern County Water Agency,” said Mr. Bartel. “There’s a lot of mutual benefits,” said Mr. Bartel. “There are hydraulic issues in different parts of the Cross Valley Canal that we’ve been trying to solve, and we could make those solutions when we expand the capacity. We can do it all at the same time and not have dual projects. So, there would be benefits, not only to the GBJPA in terms of capacity, but also to the other participants in Kern, in working on hydraulic restrictions in its existing facility. So we think it’s a win-win.”
PERMITTING AND SCHEDULE
A major decision looms by the end of the year: whether to proceed with a separate facility or a joint facility for the Aqueduct turnout. Choosing the separate facility will require securing a turnout agreement with DWR, whereas improving the existing turnout will not.
Some supplemental CEQA work remains, though the pulse flow EIR is complete and will be certified once all agreements are finalized, anticipated by spring 2027. Permitting and easements are also expected to wrap up by late 2027 or early 2028.
To access WSIP funding, Public Benefit Agreements must be established. While initial discussions with DWR and CDFW have taken place, finalizing the turnout configuration is necessary to advance these agreements, with conversations now resuming. Additionally, several other operating agreements will be required.
The project aims to secure its final funding award by spring 2028. Phase 1 construction is expected to be completed and operational by mid-2027, with the entire project online by the end of 2029.
PROJECT COSTS
Since the 2015 WSIP program application, project costs have risen significantly from $206.7 million to $301.1 million. Current capital costs are estimated at $224 million, with the total project cost—including interest, operations and maintenance, and replacement—projected to reach $301 million over its lifespan.
The project has already secured $8.5 million in federal grant funding and is actively pursuing additional federal funding opportunities. Ms. Nye noted that they plan to approach the Commission in the fall to request early funding, a step previously delayed to ensure the project could deliver the promised Delta benefits.
“Our MCED conditional award was $89.1 million, and our benefits back then were about 145 million,” said Ms. Nye. “We’ve confirmed that there is no decline in benefits. We’re hopeful that our MCED might be reviewed. As you start looking at how you may use the Los Vaqueros funding, more adjustments would be helpful, because, like all projects, we’re seeing increased costs from the time of application.”
