Throughout the state, there are more than 100 active faults that
have produced earthquakes resulting in widespread damage and
deaths. In Southern California alone, since 1933, there have been
23 significant quakes of magnitude 5.9 or greater. The San
Andreas Fault, the major fault line running through California,
is expected to be the source for a major earthquake. It was the
source for the earthquake that leveled San Francisco in 1906.
Water infrastructure is vulnerable to earthquakes:
* In the Sacramento-San Joaquin Delta, man-made levees
dating back to 1850 are identified as at risk when a major
earthquake hits.
* The U.S. Geological Survey (USGS) estimates a magnitude
7.8 temblor on the southern portion of the San Andreas Fault will
cause major damage to infrastructure, including water lines and
dams.
A panel of experts in Southern California also has identified the
following risks as a result of a major earthquake:
* Likely major damage to the main aqueducts bringing water
to Southern California from Northern California and the Colorado
River. Repairs may be hampered due to damaged roads and
large-scale fires.
* In the following days after a major quake, there may be
no water available due to infrastructure breaks and loss of
power. After that, repairs will bring supplies online slowly.
Water districts and agencies have prepared earthquake
preparedness and emergency plans to address the emergency.
Also, groundwater basins will be used as emergency reservoirs to
make up the water shortages when imported supplies are
unavailable.
The “Big One” may be inevitable, but California lawmakers face
a major undertaking in preparing for future earthquakes which
cannot be predicted. In a joint state Senate and Assembly
hearing on preparing for catastrophic earthquakes, in light of
the Turkey and Syria disasters, experts told state leaders that
bigger plans to prepare for a disaster are needed beyond small
programs. … The state must also consider how vulnerable
its massive and complicated water infrastructure is to
earthquakes. Many levee systems are in dire need of upgrades to
survive floods, let alone a major quake. [Evan Reis of the U.S.
Resiliency Council] said the water grid is highly
vulnerable because the pipes that transport water between
regions travel a long distance and often cross fault
lines.
South Coast Water District plans to decrease its reliance on
imported water by creating a local, reliable, drought-proof
supply through the Doheny Ocean Desalination Project. The
project would also provide emergency water should the delivery
of imported water be disrupted by earthquakes or other natural
disasters. … The project has been approved by the
California Coastal Commission and the State Lands Commission.
The desalination plant will use subsurface slant wells to draw
seawater in from beneath the ocean floor and pump it to the
treatment facility, where it will undergo reverse osmosis and
disinfection to produce clean drinking water.
The National Park Service is advancing its plan to remove a
Tennessee Valley dam that has been classified as having a high
risk of failure and threatens public safety at a nearby beach.
The California Coastal Commission voted unanimously Thursday to
endorse the park service’s proposed project, which also
includes restoring acres of wetland habitat that has been
affected by the dam over the decades. … Built in the early
1960s by the former landowner to attract waterfowl for hunting,
the earthen dam was one of the many artificial structures
inherited by the National Park Service after the Golden Gate
National Recreation Area was founded in 1972. The dam and its
holding pond are accessible on the Tennessee Valley Trail and
are about 900 feet from Tennessee Beach.
The mega-quakes in Turkey this week showcase how a magnitude
7.8 quake could trigger a magnitude 7.5 aftershock on a
different fault, with 60 miles of distance between the
epicenters. A similar seismic scenario could occur in
California. … In a U.S. Geological
Survey report published in 2008 detailing a
hypothetical magnitude 7.8 earthquake in Southern California,
scientists said a plausible aftershock scenario included a
magnitude 6.95 quake that would shake Sacramento and Modesto
three days after the mainshock, endangering the stability of
the levees, which are crucial for maintaining flood control and
water movement from the northern Sierra Nevada to cities across
the state.
15-minute DVD that graphically portrays the potential disaster
should a major earthquake hit the Sacramento-San Joaquin Delta.
“Delta Warning” depicts what would happen in the event of an
earthquake registering 6.5 on the Richter scale: 30 levee breaks,
16 flooded islands and a 300 billion gallon intrusion of salt
water from the Bay – the “big gulp” – which would shut down the
State Water Project and Central Valley Project pumping plants.
The 24-page Layperson’s Guide to Flood Management explains the
physical flood control system, including levees; discusses
previous flood events (including the 1997 flooding); explores
issues of floodplain management and development; provides an
overview of flood forecasting; and outlines ongoing flood control
projects.
The 24-page Layperson’s Guide to the Delta explores the competing
uses and demands on California’s Sacramento-San Joaquin Delta.
Included in the guide are sections on the history of the Delta,
its role in the state’s water system, and its many complex issues
with sections on water quality, levees, salinity and agricultural
drainage, fish and wildlife, and water distribution.
This issue of Western Water looks at the BDCP and the
Coalition to Support Delta Projects, issues that are aimed at
improving the health and safety of the Delta while solidifying
California’s long-term water supply reliability.
