California frequently experiences multi-year droughts, a natural aspect of our highly variable climate. However, climate change intensifies both the frequency and severity of these droughts, making them a significant concern. Over the past 15 years, the state has endured 11 droughts, increasing the likelihood of another occurring within the next decade. In response to the growing prevalence of severe droughts, the Department of Water Resources (DWR) is actively working to secure permits for the rapid deployment of the next drought salinity barrier at West False River when the conditions require it.
Ibraheem Alsufi, Project Manager for the West False River Drought Salinity Barrier Project, briefed the Delta Stewardship Council on the project at its March meeting.
Delta flows and the hydraulic barrier
The Delta is a complex network of interconnected waterways. It is influenced by tides, which flow in and out of the Delta twice a day. The combination of reservoir releases and snowmelt, primarily from the Sacramento River, creates a natural hydraulic barrier that prevents saltwater from the San Francisco Bay from intruding into the Delta. This barrier is essential for protecting the Delta’s ecosystem, agriculture, and water supplies for municipal and industrial use.
During wet years, abundant flows keep the Delta’s water fresh, repelling tides and protecting its beneficial uses. However, drought drastically reduces freshwater inflows, weakening the ability to fend off salinity intrusion. When saltwater intrudes into the Delta, it impacts local water users, agriculture, and downstream communities that depend on its water, and conditions cannot improve until high flows flush out the salt.
How the drought barrier improves water quality
The drought salinity barrier is a physical structure constructed at the West False River that prevents saltwater from the ocean from pushing into the Franks Tract and the Central Delta during tidal movements. This helps maintain the Delta’s water quality, ensuring it remains usable for agriculture and municipal water supplies. With the barrier in place, less water must be released from upstream reservoirs to combat salinity during droughts, thus preserving water for future use.
The location of the barrier at West False River is particularly effective because it blocks saltwater from flowing into Franks Tract, pushing it instead into the San Joaquin River and Old River, where the water tends to have lower salinity levels.
This is the same location where previous drought barriers have been placed, which has proven to be highly effective in maintaining water quality and managing salinity during critical drought conditions.
DWR’s proactive strategy
California has experienced 11 droughts within 15 years, and due to California’s cyclical nature of drought, it’s likely that within the next 10 years, drought will return, warranting the need to install the drought barrier in the future.
Previous installations were an emergency response to drought that were authorized by the Governor’s Executive Orders. So, rather than relying on emergency proclamations, DWR is working to acquire all the required permits to install a barrier in the future should there be a need.
The proposal is to construct a temporary rock salinity barrier in the West False River up to two times over 10 years, from 2026-2035. The barrier, an approximately 800-foot-long by approximately 150-foot-wide trapezoid-shaped rock structure set perpendicular to the channel, would only be constructed during dry years.
Construction, anticipated to last a month, would begin no sooner than April 1. It will likely take a month to hydrologically close and finish construction, and the barrier will be removed by November 30 of that year. If drought does persist, DWR would be able to leave the barrier in place the following year.
“It’s really not a project that we like to build, but it is effective when needed,” said Mr. Alsufi. “Just given the cyclical nature of drought in California, and unfortunately, due to climate change, we’re seeing drought return both more frequently and more intensely, and so it’s not necessarily a matter of if the barrier will be needed in the future; it really is a matter of when.”
This project is a potential covered action, and DWR plans to file a certification of consistency with the Delta Plan in April.
What about a permanent solution?
A councilmember asked about the possibility of leaving the barrier in place permanently. “We could, but then it’s a totally different project at that point,” said Jacob McQuirk, principal engineer at DWR. “This is a temporary measure that provides relief during drought conditions. If it were to be permanent, there would be another level of planning that DWR would have to undertake.”
“What we’re looking at now is the drought barrier could be in for less than a year or up to 20 months. … so if one year does it well enough then great, we’ll remove it at the end of that season. If we’re still in the drought and still need that protection, we’ll leave it for the next year and remove it the following fall period.”
Mr. McQuirk said one permanent solution is the Franks Tract Futures Project, which would construct wetlands and habitats that would have about the same benefits as the barrier, but it’s an expensive project that would take many years to design and fund.
