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Drought Triggers Need for Emergency Salinity Barrier in Delta

from ACWA
April 17,2014

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For the first time since the drought of 1976-‘77, state officials are moving ahead with plans to build a temporary rock salinity barrier in the Sacramento-San Joaquin Delta to keep saltwater from the San Francisco Bay from moving up into the Delta where it could mix with fresh water and threaten drinking water supplies.
The emergency action, announced today by the California Department of Water Resources, was reached after extensive consultation with officials from federal, state and wildlife agencies. Installation of the barrier – expected in early May across West False River – will require numerous permits from various state and federal agencies. The barrier would be removed six months later in November.
“We had hoped not to have to install any temporary emergency barriers in the Delta this year,” DWR Director Mark Cowin said in a written statement.  “But conditions stayed dry through March and April.  The West False River emergency barrier would provide a buffer that otherwise would have come from reduced Delta pumping. This summer, there is no Delta pumping to reduce.  The barrier would help afford us time to move water from Oroville and Shasta should we need to push back saltwater intruding into the Delta.”
State and federal water and wildlife officials made the decision in conjunction with the Real-Time Drought Operations Management Team.  The barrier is described as “a pile of basketball-size rocks” the would be stacked across the 750-foot-wide channel that would still allow limited water flow upstream and downstream, depending upon tides.
Keeping saltwater from reaching the central Delta is crucial since a large portion of the state’s freshwater supplies travel through this part of the Delta.  The barrier would help prevent saltwater contamination of water supplies.
Typically when saltwater threatens to encroach deeper into the Delta, water project operators try to repel it either by slowing the pumping of water from the Delta or increasing the amount of water flowing into the Delta from upstream reservoirs.
In this fourth year of drought, however, Delta pumping by the state and federal water project operators already is negligible.  It also takes three to five days for fresh water released from Lake Oroville or Shasta Lake to reach the Delta, which could be too lengthy of a time to provide needed relief.  An emergency barrier would provide an additional tool to help limit salinity intrusion prior to arrival of fresh water from upstream reservoirs, DWR officials stated in a press release.
To avoid flood season and potential harm to migratory fish, removal of the emergency barrier would finish no later than Nov. 1. The removal is expected to take 45 to 60 days. Construction, monitoring, mitigation and removal of the rock barrier are estimated to cost roughly $28 million, to be paid for with a mix of funding from Proposition 50, a $3.4 billion water bond approved by voters in November 2002, and general fund dollars.
Multiple Permits Needed
For the past year, DWR has worked closely with multiple agencies on the issue of emergency salinity barriers.  DWR must obtain permits and a Temporary Urgency Change Permit renewal from the State Water Resources Control Board, a permit for levee modification from the U.S. Army Corps of Engineers, and a California Endangered Species Act permit from the California Department of Fish and Wildlife. In addition, DWR must consult with the U.S. Fish and Wildlife Service and National Marine Fisheries Service on protections for Delta smelt, Chinook salmon and other listed species.  All of these agencies have worked cooperatively on the Real-Time Drought Operations Management Team during this last year of drought.
The permit application process is underway, and DWR hopes to begin installation of the emergency barrier on May 8.
The trapezoid-shaped barrier, about 12 feet wide at the top, also will temporarily block boat passage on West False River and be marked by warning signs, lights, and buoys.  Alternative routes between the San Joaquin River and interior Delta, including Bethel Island marinas, are available.  DWR officials said in a press release that the West False River site raises fewer concerns for threatened and endangered fish than other potential barrier sites the department considered.
Earlier Consideration of Emergency Barriers
Last year DWR studied the potential impacts of potential temporary barriers at three locations:  Steamboat Slough, Sutter Slough, and West False River.  The analysis found anticipated impacts could be mitigated to a less-than-significant level.  DWR received and reviewed considerable public comments on the Initial Study and Proposed Mitigated Negative Declaration. They are available here.
Although DWR is seeking permits from various agencies, the April 1 Executive Order by Governor Brown helps expedite installation of the West False River barrier in time to address emergency drought conditions.  The Governor’s Executive Order declared existence of conditions of extreme peril to public safety and directed DWR to implement emergency drought barriers if necessary.
The Executive Order also suspends some California Environmental Quality Act requirements for certain drought relief actions, including installation of emergency drought barriers.
DWR considered the installation of emergency drought barriers in 2014 but determined in late May of last year that they would not be needed, in part because February and March storms improved water supply conditions.
More drought information is available at DWR’s Drought website:
Information about emergency drought barriers is available here.
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