Delta salinity barrier to stay in 2022

Press file photo

The California’s Department of Water Resources has announced it will keep in place the West False River salinity barrier until November of next year.

In response to continuing drought conditions, California’s Department of Water Resources (DWR) announced that it will keep the West False River salinity barrier in place until November 2022.

Construction of the rock barrier was completed in June, and the emergency permit issued by the State Water Resources Control Board (SWRCB) originally required its removal by Nov. 30, 2021.

“Once the Delta gets salty, it renders it not useful for all beneficial uses,” said Jacob McQuirk, operations and maintenance manager for DWR. “That’s interior agriculture. That’s folks like the Contra Costa Water District that rely on it to fill Los Vaqueros. Everybody that relies on that fresh Delta water will have to wait for a real winter precipitation event to clear it out. That becomes the issue. Once you lose it, the only way to get it back is Mother Nature divvying up some precipitation. We can’t make it any better, mind you. We can only protect what we’ve got.”

“DWR is scheduled to complete removal of the barrier by November 30, 2021,” McQuirk wrote in a letter dated Sept. 24 addressed to the U.S. Army Corps of Engineers. “However, based on current drought conditions, it is imperative that the barrier remain in place to protect water quality. The requested delay to complete removal of the barrier by November 30, 2022 is necessary to provide continued protection of the beneficial uses of water in the Central and South Delta during the ongoing, severe drought.”

The barrier is located 0.4 mile east of the confluence of the San Joaquin and West False rivers between Jersey and Bradford islands. It has a trapezoidal shape and is 800 feet long with a 200-foot-wide base. The top of the barrier is 12 feet wide. Boat traffic is completely blocked by the barrier in its present design.

An SWRCB report completed in response to DWR’s emergency request to install the barrier earlier this year stated, “During drought conditions, the release of water stored in upstream reservoirs may be insufficient to repel salinity moving upstream from San Francisco Bay. According to DWR’s analyses, without the protection of the drought salinity barrier, saltwater intrusions could render Delta water unusable for agricultural needs, reduce habitat value for aquatic species and affect roughly 25 million Californians who rely on the export of this water for personal use. Installation of the temporary rock barrier at West False River would limit salinity intrusion into the Central and South Delta and would potentially conserve water for a variety of uses system wide.”

McQuirk said that since its installation the barrier has been functioning well as a mechanism to keep saltwater from intruding into the Delta’s interior – a job that is usually accomplished by the release of fresh water stored in upstream reservoirs like Lake Oroville. But critically low water levels in those reservoirs means less water is available for release. Without efforts to block the intrusion of saltwater, it would make its way into the South Delta by way of the Old River and eventually reach the State Water Project pumps near Tracy.

“In order for the conveyance system to work, it requires the release of fresh water,” McQuirk said. “You’ve got to keep the interior Delta fresh. If you don’t, you cannot use it as a conveyance facility.”

In addition to the U.S. Army Corps of Engineers, DWR has submitted its revised plan to the California Department of Fish and Wildlife and the SWRCB.

There currently are no efforts underway to remove the barrier. In early January, DWR plans to open a 400-foot-wide and 12-foot-deep notch in the barrier that will allow some boat traffic and fish to cross the obstruction. If drought conditions continue into 2022, the notch will once again be filled in April.

“Some people have asked if leaving this barrier in place will create some sort of flood risk,” McQuirk said. “The answer really is ‘no.’ This is a tidal channel. The reason that the water level goes up and down is the tide.”

Reviewing data from the West False River tidal gauge from 2017, a wet year, DWR determined that even large amounts of precipitation had minimal effects on tidal heights.

However, there have been issues associated with the barrier. Several of those problems are related to increased current velocities, particularly those flowing south out of Fishermans Cut. Fishermans Cut runs straight along a north-south line that separates Bradford Island and Webb Tract. David Gloski, a Bethel Island resident and engineer, noted that the increased current speed required the state to employ a more powerful ferry to serve both Bradford Island and Webb Tract when a similar barrier was constructed in 2015 in response to the drought.

The increased current is also impacting Little Franks Tract, a 330-acre sunken island north of Bethel Island. It’s managed by the California Department of Parks and Recreation as part of the Franks Tract State Recreation Area.

“The water comes flying down Fishermans Cut and impinges on the (Little Franks Tract) levees,” Gloski said. “It started a little opening in 2015, and it’s opened up even more now. State Parks doesn’t care if the levees go away. Even though (the levees) define their park and Franks Tract Futures project needs the levees, they seem to not care, although I’m trying to get them to care. So when the water comes flying through (Fishermans Cut) it’s trying to get south and flow into our sloughs here.”

As the current crosses the shallow water of Little Franks Tract, it picks up sediment that is subsequently deposited along the north shore of Bethel Island in Piper Slough.

“When this opens up, it picks up all the silt and starts pouring it in here,” Gloski said. “There are some people here that can’t even put their hydrolifts down because we’re filing in with silt. All of the soil from Little Franks Tract is coming into our slough down here.”

Recognizing that DWR will soon be moving tons of rock when the notch is opened in the barrier, Gloski has suggested that the material be used to stabilize the levees in Little Franks Tract, an idea that DWR is considering. However, the effort will require coordination with multiple agencies and the application for necessary permits.

“DWR can’t just go dropping rocks wherever it wants willy-nilly,” Gloski said.

When DWR requested emergency approval to install the barrier earlier this year, the agency was criticized by some for not having a fully vetted plan in place to respond to drought conditions, which are common in the state. Michael Brodsky, attorney for the Discovery Bay-based Save the California Delta Association, was one of those critics.

“It’s really not an emergency in the sense that nobody’s surprised that there’s another dry year, and that this has to be done,” Brodsky said in June. “They should really have a long-term plan and do an environmental impact report and look at some alternatives so it’s a fully informed decision. Why is this coming as a surprise? Why can’t (DWR) plan this as a long-term project?”

DWR is now engaged in an effort that will, if approved, allow the agency to install a rock barrier in West False River for up to two years, twice more in the next 10 years. Unlike the emergency approvals previously used by DWR, permits for these actions will require a California Environmental Quality Act (CEQA) study and allow for a period of public review and comment. A CEQA document is expected to be ready for review and comment in the spring.