The federal government passed the Endangered Species Act in 1973,
following earlier legislation. The first, the Endangered
Species Preservation Act of 1966, authorized land acquisition to
conserve select species. The Endangered Species Conservation Act
of 1969 then expanded on the 1966 act, and authorized “the
compilation of a list of animals “threatened with worldwide
extinction” and prohibits their importation without a permit.”
Federal reserved rights were created when the United States
reserved land from the public domain for uses such as Indian
reservations, military bases and national parks, forests and
monuments. [See also Pueblo Rights].
Flood forecasting allows flood control managers to predict,
with a high degree of accuracy, when local flooding is
likely to take place.
Forecasts typically use storm runoff data, reservoir levels and
releases to predict the rise in river levels.
In Northern California the National Weather Service, in
cooperation with the state’s California-Nevada River Forecast
Center in Sacramento, forecasts flooding.
When people think of natural
disasters in California, they typically think about earthquakes.
Yet the natural disaster that residents are most likely to face
involves flooding, not fault lines. In fact, all 58 counties in
the state have declared a state of emergency from flooding at
least three times since 1950. And the state’s capital,
Sacramento, is considered one of the nation’s most flood-prone
cities. Floods also affect every Californian because flood
management projects and damages are paid with public funds.
Overview
During heavy rains and atmospheric rivers that barrel through
California, large rivers as well as smaller streams and creeks
can become dangerous. Most of the state is vulnerable to
flooding. Areas adjacent to rivers are prone to flooding as are
lowland coastal regions. Parts of Southern California often
experience flash floods.
The Central Valley, bordered by the Sierra Nevada on the east and
the Coast Range on the west, is similar to a large bowl that
collects most of California’s rainfall. More than 1.3 million
Californians live and work in the floodplains of the Sacramento
and San Joaquin valleys, where flood risks are among the
highest in the nation.
Watch a video of the
Sacramento weir and the Yolo Bypass.
Flooding in California is not caused only by hard rains. In the
Sacramento-San
Joaquin Delta, there are approximately 1,100 miles of levees
protecting 700,000 acres of lowland. In the Suisun Marsh, at the western edge
of the Delta, there are approximately 230 miles of levees
protecting over 50,000 acres of marshland. According to the
California Department of Water Resources, a 6.5-magnitude
earthquake in the western Delta could produce more than 30 levee
breaches on 16 Delta islands, causing about $30 billion in
damages.
The Delta is particularly vulnerable to flooding because of its
aging, insufficient levees. On a sunny day in 2004, a levee
crumbled and sent surging river water into Upper and Lower Jones
Tract west of Stockton, causing $90 million in damages, including
millions of dollars in direct flood-fighting and levee-repair
costs and millions more in losses of crops and property.
Upstream dams have done much to reduce flooding
risks in California, but whether downstream levees can provide
adequate protection in some areas is a big concern. These
concerns deepened in 2005 after the destruction of New Orleans by
Hurricane Katrina brought new attention to levees throughout the
United States, including California.
Situated at the confluence of two major rivers, the city of
Sacramento is considered the second-most flood-prone major city
in the United States after New Orleans. State laws enacted
in 2007 to implement better flood management policies and
practices also required that Central Valley communities ensure
they can safely withstand a 200-year flood by 2025.
In 2018, Sacramento received about $1.8 billion in federal money
to strengthen levees, raise Folsom Dam and widen the Sacramento
Weir, which channels flood waters into the Yolo Bypass.
Challenges
Flood management is inextricably intertwined with politics,
economics and values. Meanwhile, historic floodplains have been
heavily developed for agricultural, commercial and residential
use.
The effects of climate
change further complicate flood risk management in
California. Precipitation and runoff patterns are changing, which
could affect the timing and magnitude of flows. Expected effects
include more precipitation falling as rain rather than snow. An
earlier melt to the winter snowpack is also expected. In
addition, the California Climate Change Center says more coastal
floods are expected due to increasingly severe winter storms,
rising sea levels and high tides. These severe weather events are
expected to cause more frequent and more severe flooding, erosion
and damage to structures along the coast.
California’s flood protection system
is facing unprecedented challenges, including increasing
floodplain development, rising flood peaks, higher costs that
delay fixing problem levee sites,
the need for environmental protection and greater state liability
for levee breaches.
Through the years, California voters have approved water bonds
with flood protection elements, including 2018’s Proposition 68,
which, among other things, included $1.3 billion for flood
protection improvements.
In 2022, the Central Valley Flood Protection Board updated the
2017 Central Valley Flood Protection Plan, setting out a $25-$30
billion blueprint for managing Central Valley flood risk over the
next three decades to better respond to a changing and more
volatile climate. Among the revisions laid out in the update are
plans to strengthen urban levees to protect populated areas and
set back levees in more rural areas to allow flood waters to
spread out, slow down and sink into the ground. The update also
calls for using weather forecasts to more flexibly operate flood
control reservoirs, capturing and storing flood waters in
aquifers and reservoirs, and more multi-benefit flood
improvements that mesh with other statewide water priorities.
Management Issues
As impacts of climate change become more apparent, flood
management is increasingly critical in California, particularly
when heavy winter rains fall. Compounding the issue are
human-made flood hazards such as levee instability and stormwater
runoff. Flood management includes giving constricted rivers more
breathing room by setting back levees, reducing floodplain
development and giving equal weight to environmental and economic
factors in making management decisions.
Flood management is often in conflict with water supply practices
and needs. Flood control managers must keep enough reservoir
storage space available to accept runoff surges and reduce the
risk of floods downstream, while water suppliers hope to keep
enough water in reservoirs to protect against drought. New
strategies, known as Forecast Informed Reservoir Operations
(FIRO), are being implemented that give reservoir operators more
flexibility to determine storage needs based on what the weather
forecast holds instead of sticking with an inflexible guideline.
Additionally, flood control involves many different local, state
and federal agencies [see list at bottom of the page], and their
management philosophies change with the political and economic
times. The state also has many local flood management agencies
responsible for the day-to-day operations and maintenance of
facilities, development and implementation of flood management
and stormwater drainage plans, and coordination with other state
and federal agencies.
Regional Management Efforts
In Sacramento, the Sacramento Flood Control Project consists of a
system of levees, overflow weirs, pumping plants and bypass
channels. In times of high flows, the Sacramento and Yolo
bypasses divert vast amounts of water from the Sacramento River.
The Central Valley has a flood
protection network that includes 23 reservoirs with flood
detention space and more than 1,760 miles of federally designated
levees, overflow weirs and channels. In addition, a series
of dams were built on the western slope of the Sierra Nevada and
Cascade mountain ranges for both flood control and water supply.
These include Shasta Dam on the Sacramento River, Oroville Dam on
the Feather River and Folsom Dam on the American River.
In the more arid Southern California region, flash floods
prompted the formation of the state’s first flood control
district in 1915 in Los Angeles. Today, the Los Angeles County
Department of Public Works, in coordination with the U.S. Army
Corps of Engineers, operates 14 dams, 115 debris basins, 26
groundwater recharge facilities, 524 miles of major channels, 29
pump plants, 77,990 catch basins, and 2,800 miles of tributary
storm drains.
The state also has more than 2,600 miles of levees and sloughs
that fan out from the San Pablo Bay northeast of San Francisco up
to Sacramento and Stockton. Many of the state’s levees are simply
mounds of river mud constructed in the 1800s and not designed to
protect buildings.
Despite progress, flood management still faces significant
obstacles. Many floodplains already are developed, and providing
rivers with more room to roam is controversial, expensive and
difficult. Virtually all of the natural floodplains along the Los
Angeles River are urbanized. Much of the city of Sacramento lies
in the historic floodplain. Other areas throughout the state are
experiencing rapid development.
Key Agencies in Flood Management
The U.S. Army Corps of Engineers (Corps) is
the primary federal flood management agency, developing
guidelines for flood management storage in federally funded
reservoirs and monitoring reservoir operations. The Corps also
constructs flood management projects, operates multiple-purpose
projects, and provides resources, equipment and personnel for
emergency floods.
The Bureau of Reclamation operates several
multipurpose projects throughout the state, including the Central
Valley Project and the Colorado River system.
The National Weather Service
(NWS)issues weather forecasts and flood
warnings. It helps communities establish flood warning systems
and conducts flood hazard analyses and provides other technical
assistance.
The Federal Emergency Management Agency
(FEMA) runs the National Flood
Insurance Program, disaster planning and recovery programs. FEMA
works closely with states and communities and provides financial
and technical assistance, flood hazard maps and data to better
manage floodplains.
The California Department of Water
Resources (DWR) operates the State Water Project,
runs the state-federal Flood Operations Center and assists the
NWS in flood forecasting. It is responsible for the operation and
maintenance of the Sacramento and San Joaquin flood management
projects. DWR funds flood management projects outside the Central
Valley, carries out the state’s floodplain management laws and
coordinates the floodplain management aspects of FEMA in
California.
The Central Valley Flood Protection Board
cooperates with the Corps in the planning, construction,
operation and maintenance of flood management projects in the
Central Valley. Once a project is completed, the board holds the
federal government harmless, accepts legal responsibility for its
maintenance and then turns the maintenance responsibility over to
a local agency or DWR. The board also controls, through a
permitting process, activities and development in
state-designated floodways.
The California Office of Emergency Services
(OES) may allocate funds for investigation, estimates, reports
and repairs regarding disaster recovery financial assistance for
flood management works that do not come under the provisions of
another authority. It runs FEMA’s hazard mitigation program in
California.
With the dual threats of obsolete levees and anticipated rising sea levels,
floodplains—low
areas adjacent to waterways that flood during wet years—are
increasingly at the forefront of many public policy and water
issues in California.
Adding to the challenges, many floodplains have been heavily
developed and are home to major cities such as Sacramento. Large
parts of California’s valleys are historic floodplains as well.
Hydraulic fracturing, commonly known as fracking, injects high
pressure volumes of water, sand and chemicals into existing wells
to unlock natural gas and oil. The technique essentially
fractures the rock to get to the otherwise unreachable deposits.
The United States
Geographical Survey (USGS) defines freshwater as containing
less than 1,000 milligrams per liter dissolved solids. However,
500 milligrams per liter is usually the cutoff for municipal and
commercial use. Most of the Earth’s water is saline, 97.5
percent with only 2.5 percent fresh.
Located just north of Fresno, the
Friant Dam helps deliver water as it runs towards the Merced River, though its
environmental impacts have caused controversy.
A part of the federal Central Valley
Project, the 152-mile Friant-Kern Canal in California’s San Joaquin Valley plays a
critical role in delivering water to 1 million acres of farmland
and 250,000 people from the Fresno area south to Bakersfield.