Drought Triggers Need for Installation of Emergency Salinity
Barrier on Delta Channel
Temporary Barrier Would Deter Saltwater and Protect Delta Water Quality
SACRAMENTO --
Faced with potentially insufficient water supplies to
repel salinity in the Sacramento-San Joaquin Delta, the California Department
of Water Resources (DWR), in consultation with federal and state water and
wildlife agencies, is moving to install an emergency, temporary rock barrier
across a Sacramento-San Joaquin Delta channel.
DWR seeks to
install a single emergency salinity barrier across West False River in May, to
be removed six months later in November. State and federal water and wildlife
officials, working as a Real-Time Drought Operations Management Team, have
determined that the barrier would help deter the tidal push of saltwater from
San Francisco Bay into the central Delta. The barrier would be essentially a
pile of basketball-size rocks across the 750-foot-wide channel that still allows
limited water flow upstream and downstream, depending upon tides. DWR, operator
of the State Water Project, is seeking multiple permits from various agencies
to accelerate installation.
Keeping
saltwater from the central Delta is a priority, as 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 used by people who live
in the Delta; Contra Costa, Alameda, and Santa Clara counties; and the 25
million people who rely on the Delta-based federal and state water projects for
at least some of their 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, Delta pumping by the state and federal water projects is already
negligible. It takes three to five days for fresh water released from Lake
Oroville or Shasta Lake to reach the Delta. An emergency barrier would provide
an additional tool to help limit salinity intrusion prior to arrival of fresh water
from upstream reservoirs.
“We had hoped
not to have to install any temporary emergency barriers in the Delta this year,”
said California Department of Water Resources Director Mark Cowin.
“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.”
The emergency
barrier also would help mitigate a worst-case circumstance this summer in which
upstream reservoirs lack sufficient water to meet the minimum outflow
requirements to limit Delta salinity intrusion.
Emergency
barrier removal would finish no later than November 1 to avoid flood season and
potential harm to migratory fish. Removal is expected to take 45 days to 60
days.
Multiple Permits Needed
For the past
year, DWR has worked closely on the issue of emergency salinity barriers with multiple
agencies, including the U.S. Bureau of Reclamation, operator of the Central
Valley Project. 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 for the past year.
The permit
application process is underway, and DWR hopes to begin installation of the
emergency barrier on May 8.
It would be
erected across West False River about 0.4 miles east of its confluence with the
San Joaquin River, between Jersey and Bradford Islands in Contra Costa County.
The location is about 4.8 miles northeast of Oakley.
Construction,
monitoring, mitigation and removal 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.
The
trapezoid-shaped barrier, about 12 feet wide at the top, 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 (see attached map). The West False River
site raises fewer concerns for threatened and endangered fish than other
potential barrier sites considered by DWR.
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, available at
http://www.water.ca.gov/waterconditions/docs/Emergency_Drought_Barriers_Initial_Study_and_Proposed_
Mitigated_Negative_Declaration.pdf.
At this time,
DWR is not pursuing installation of temporary emergency barriers at Sutter
Slough or Steamboat Slough. 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 suspends some California
Environmental Quality Act requirements for certain drought relief actions,
including installation of emergency drought barriers.
DWR last used
emergency drought barriers to reduce salinity intrusion in 1976-77. 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. Planning
for future emergency drought barriers continued after last year’s decision,
with a focus on West False River, Steamboat Slough, and Sutter Slough. Earlier
this year, based on the input of Delta residents, the Department also
considered the feasibility and effectiveness of barriers on Miner Slough in the
western Delta and on Steamboat Slough downstream of its confluence with Sutter
Slough.
Emergency
drought barriers on Miner Slough and Steamboat Sloughs were eliminated from
consideration because of U.S. Fish and Wildlife Service concerns about
potential effects on threatened Delta smelt.
Current
Drought Emergency The three-year period from 2012 through 2014 was the driest
three-year period on record in California, and 2015 opened with the driest
January in the state’s weather record history. The Sierra Nevada snowpack typically
peaks by April 1; this year, the snowpack was measured at five percent of historic
average, the lowest measurement in recorded history.
Governor Brown
declared a drought State of Emergency on January 17, 2014 and directed state
officials to take all necessary actions to prepare for water shortages. The
State Water Resources Control Board on March 17, 2015 announced new
restrictions on water use, including limiting outdoor watering to two days per
week and prohibiting lawn watering during rainfall and during the next two
days. Earlier this month, the governor directed the State Water Resources
Control Board to implement mandatory water reductions in cities and towns
across California to reduce water usage by 25 percent.
Conservation –
the wise, sparing use of water – remains California’s most reliable drought
management tool. Each individual act of conservation -- such as letting the
lawn go brown or replacing a washer in a faucet to stop a leak – makes a
difference over time.
Visit
SaveOurWater.com to find out how everyone can do their part, and visit
drought.ca.gov to learn more about how California is dealing with the effects
of the drought.
More drought
information is available at DWR’s Drought website:
http://water.water.ca.gov/waterconditions/waterconditions.cfm
Information
about emergency drought barriers is available here:
http://www.water.ca.gov/waterconditions/emergencybarriers.cfm.
.