An acre-foot is a common way in the U.S. to measure water volume
and use. It is the amount of water it takes to cover an acre of
land one foot deep. An acre is about the size of a football
field.
An acre-foot of water equals 325,851 gallons, and historically
that was enough to serve the needs of two families for a
year in California.
As the single largest water-consuming industry, agriculture has
become a focal point for efforts to promote water conservation.
In turn, discussions about agricultural water use often become
polarized.
With this in mind, the drive for water use
efficiency has become institutionalized in agriculture
through numerous federal, state and local programs.
California’s rich agricultural productivity comes with a price.
The dry climate that provides the almost year-round growing
season also can require heavily irrigated soils. But such
irrigation can degrade the local water quality.
Two of the state’s most productive farming areas in particular,
the west side of the San
Joaquin Valley and parts of the Imperial Valley in Southern
California, have poorly drained and naturally saline soils.
Few regions are as important to California water as the Sacramento-San Joaquin
Delta, where the Sacramento and San Joaquin rivers converge
to discharge into San Francisco Bay.
Agriculture drainage issues date back to the earliest farming. In
ancient times, farmers let fields stay fallow hoping rain would
flush out salt.
Today, salt and other contaminants continue to cause agricultural
drainage problems, particularly in California. Whether a field is
adequately drained, or saturated with water, the water still has
to be removed.
The disposal of this often-contaminated water continues to be a
challenge in California, with the environmental effects of
selenium and other drainage-related elements changing the course
of drainage planning.
Algal blooms are sudden overgrowths
of algae. Their occurrence is increasing in California’s
rivers, creeks and lakes and along the coast, threatening the
lives of people, pets and fisheries.
Only a few types of algae can produce poisons, but even nontoxic
blooms hurt the environment and local economies. When masses
of algae die, the decaying can deplete oxygen in the water to the
point of causing devastating fish kills.
As one of the most productive agricultural regions in the world,
the Imperial Valley
receives its water from the Colorado River via the
All-American Canal. Rainfall is scarce in the desert region at
less than three inches per year and groundwater is of little
value.
Alluvium generally refers to the clay, silt, sand and gravel that
are deposited by a stream, creek or other water body.
Alluvium is found around deltas and rivers, frequently
making soils very fertile. Alternatively, “colluvium” refers to
the accumulation at the base of hills, brought there from runoff
(as opposed to a water body). The Oxnard Plain in Ventura
County is a visible alluvial plain, where floodplains have
drifted over time due to gradual deposits of alluvium, a feature
also present in Red Rock Canyon State Park in Kern County.
The American River originates high
in the Sierra Nevada just west of Lake Tahoe, in the Tahoe and
Eldorado national forests.
The birthplace of the California Gold Rush, the river today is a
prime recreational destination and a major water supply source
for the federal Central Valley Project.
Anadromous fish are freshwater fish
that migrate to sea and then return to spawn in fresh water.
In California, anadromous fish include coho salmon, chinook
salmon and steelhead. Those inhabiting rivers across the Central
Valley have experienced significant declines from historical
populations. This is due to drought, habitat destruction, water
diversions, migratory obstacles such as dams, unfavorable ocean
conditions, pollution and introduced predator species.
Applied water refers to water delivered by an application to a
user, either indoors or outdoors. Applied water use typically
occurs in an agricultural or urban setting.
In agriculture, applied water is typically supplied through
irrigation, which uses such devices as pipes and sprinklers.
There are also different types of systems including gravity flow
and pressurized systems.
With soil absorbing applied water and being porous (some water
can move down below a plant’s root zone), it is necessary to
apply more water than a crop might need.
California law allows rivers, streams, lakes and other surface
water to be diverted at one point and appropriated (used)
beneficially at a separate point.
This “appropriative right” contrasts with a “riparian right,” which is based
on ownership of property adjacent to surface water.
The legal term “area-of-origin” dates back to 1931 in California.
At that time, concerns over water transfers prompted enactment of
four “area-of-origin” statutes. With water transfers from
Yosemite’s Hetch Hetchy Valley to supply water for San Francisco
and from Owens Valley to Los Angeles fresh in mind, the statutes
were intended to protect local areas against export of water.
In particular, counties in Northern California had concerns about
the state tapping their water to develop California’s supply.
ARkStorm stands for an atmospheric
river (“AR”) that carries precipitation levels expected to occur
once every 1,000 years (“k”). The concept was presented in a 2011
report by the U.S. Geological Survey (USGS) intended to elevate
the visibility of the very real threats to human life, property
and ecosystems posed by extreme storms on the West Coast.
Both the drought and high nitrate levels in shallow groundwater have necessitated deeper
drilling of new wells in the San Joaquin Valley, only to expose
water with heightened
arsenic levels. Arsenic usually exists in water as arsenate
or arsenite, the latter of which is more frequent in deep lake
sediments or groundwater with little oxygen and is both
more harmful and difficult to remove.
Atmospheric rivers are relatively
narrow bands of moisture that ferry precipitation across the
Pacific Ocean to the West Coast and are key to California’s
water
supply.
Auburn Dam, also known as the Auburn-Folsom South Unit, is an
unfinished federal Central Valley Project facility on the north
fork of the American River above Folsom Dam.
Work on the dam was halted in 1977 following a magnitude 5.7
earthquake in 1975 near Oroville Dam, some 50 miles away, raising
questions about the Auburn Dam’s safety. The dam remains unbuilt.
Jean Auer (1937-2005) was the first woman to serve on the
California State Water Resources Control Board and a pioneer for
women aspiring to be leaders in the water world.
She is described as a “woman of great spirit who made large
contributions to improve the waters of California.” She was
appointed as the State Water Board’s public member by
then-Governor Ronald Reagan and served from 1972-1977 during a
time period that included the passage of the federal Clean Water
Act. She became part of the growing movement for water quality
regulations to stop water pollution.
