From Desert to Oasis: Land Use Transformation of Central and Southern California through Water Projects in the last 100 years
March 12, 1999
History
Since
its heyday during the Gold Rush era, the State of California has risen to
become a political and economic powerhouse, both in the nation and
worldwide. Home to nearly 15% of the
nation’s population (Templin, 1998) and boasting two of the largest urban
centers in the continental U.S., California is an economic pillar of the nation
and frontrunner in nearly every field- from the software giants of Silicon
Valley to rich agricultural lands running from
Mt. Shasta in the North to the
Mexico border in the South. In fact,
were California to secede from the Union, it would boast one of the largest
GNP’s in the world.
This was
not always the case. California, home
to some 33 million people and the source of food for millions more, was not
always as fertile and productive as it is today (Templin, 1998). In fact, when the first settlers rode into
the Los Angeles basin they found not a natural oasis but shrubland and
semi-desert, the norm for most of the Southern California. The soils were fertile, but water was
pitifully scarce.
Over the
past hundred and fifty years, California has been transformed into an urban and
agricultural mecca primarily through the use of water control projects centered
around dams and diversion canals, as well as heavy groundwater
withdrawals. The state withdraws 45.9 billion gallons of water per day, the
largest by nearly double of any state (Solley, 1998)
Southern California Urban Areas
California’s
history of water projects has a long and interesting legacy. In the 1860’s, when
San Francisco was a boomtown, the sprawling metropolis we know as Los Angeles
was a dusty little town of about 13,000 people. (Reisner, 1993) The town’s water resources consisted of the
Los Angeles River- actually a seasonal creek- and a number of artesian
wells. These wells began to run dry
within a few years due to overuse. Over
the next few decades there were a few city officials who had grand plans for a
booming metropolis that would someday rival San Francisco. They realized that their town could never
support much of a population with its meager water supply, so they began
looking for nearby water resources that they could somehow divert to the
city. “Nearby” proved to be 250 miles
away, in California’s Owens Valley. (Reisner, 1993)
The
city sent a number of agents to the valley posing as land speculators who
bought up all the land they could along the riparian corridor. Through trickery
and subterfuge, the city of Los Angeles obtained the water rights of the entire
Owen’s Valley in the early 1900’s, and began plans to divert it.
Completed
in 1913, the aqueduct was instrumental in transforming the Los Angeles basin
into the oasis we see today. Yet in
time the city outgrew its new water supply and began to look even further away
for more water.
Built
in 1935 after heavy legislation by the western states and Southern California
in particular, Hoover Dam captures the mighty Colorado River, and partitions
its water to the western states.
Southern California used its entire 4.4 million cubic feet allotment
from the beginning, and immediately began plans for yet more water
projects.
The
California Aqueduct begins at the Oroville Dam in Northern California, joins
the Sacramento River, travels through the Delta, is siphoned through 10,000
horsepower pumps, and pumped uphill- ultimately 3500 feet over the Tehachapi
Mountains before it drops into the L.A. basin.
(Reisner, 1993) This ‘river that
runs backwards’ irrigates a large percentage of the Central Valley’s farmland
on the way south before it hits Los Angeles.
Agriculture
There is
an oft quoted saying that “in the West, water flows uphill towards money” and
California is no exception. California
farming simply would not exist at its present scale if it were not for
multi-million dollar irrigation projects.
Corporate
farming in the state holds considerable muscle within the legislature, and has
historically been instrumental in the passing of water development
projects.
The
trouble with these supply-side solutions is that their very success creates new
problems down the road. The classic
problem with water projects in the state is this: farmers begin to deplete groundwater reserves. They argue that they need more water if they
are going to continue to be world leaders in agriculture. The Federal Government eventually builds a
water project, and tries to pass some cost on to farmers. Farmers complain that they cannot pay that
much for water, so the government subsidizes the water. The water is so cheap that farmers put more
land into production, or grow water intensive crops like alfalfa and cotton.
Even the mindset of those put in
charge of precious water resources is horrifying. As a former head of the Water Conservation Board so eloquently
stated, “…when we use it up, we’ll just have to get more water from somewhere
else.” (Reisner, 1993)
Much of
the state’s economic and agricultural might lay upon shaky foundations,
balanced precariously upon water resources who’s sustainability is
questionable. The majority of the
state’s economy is built upon the manipulation of fragile- and in the case of
groundwater- finite water resources.
The
destruction of freshwater ecosystems, as well as waterfowl and fish migration
habitats- directly through land use change and indirectly through dams and
diversions- is a major problem associated with water projects today. Dams in particular significantly alter
riparian ecosystems and cause serious problems.
Destruction
of estuary ecosystems and surrounding marshland in California have been
staggering. “More than 90 percent of the State’s wetlands have been drained,
mostly for agricultural purposes.”(USGS, 1999) This terraforming has had
significant impacts on the state as a whole.
Besides providing habitat for numerous resident and visiting species,
wetlands provide buffers for large precipitation events and are key to
groundwater recharge.
Both
directly and indirectly, dams interfere with fish species. Besides physically blocking upstream access,
dams alter the sediment load downstream, since all sediment is captured behind
it.
As a result, many rivers have incised, undermining bridges and other structures at a cost of $ millions annually. Gravels have been transported downstream, leaving only a coarse lag of cobbles unsuitable for spawning by salmon, contributing to the catastrophic decline in salmon runs in California this century. (Kondolf, 1994)
Dams inhibit fish reproduction in other ways as well:
…spring runoff is held back in giant reservoirs for release later in summer, when shipping, farming, and hydropower production require more water. Salmon fry end up dying in huge numbers for lack of sufficient current to aid their seaward journey. (Postal, 1992)
For all
of their drawbacks, dams benefits do not even last that long. They have
relatively short lifespans- in the range of 50 to 100 years depending on the
sediment load of the river. As the dam silts up, storage capacity is reduced,
and with it the benefits of flood control and electric generation
potential. The Black Butte Reservoir in
California, for instance, had a capacity of 160,000 acre-feet when it was
constructed. Ten years later, that
capacity was reduced to 149,000 acre-feet due to siltation. Similar trends can be seen in every dam ever
built. (Reisner, 1993)
Desert to farmland- and back to desert
Irrigated
water tends to be high in salt content, because it comes from rivers that have
been leaching salts from their drainage basins over thousands of square miles. The problem is compounded by damming rivers,
because enormous evaporation in reservoirs makes the remaining water even more
concentrated in salinity. For example,
water on the Colorado River is continually diverted and returned along its
entire stretch, becoming saltier and saltier as it flows south. In areas of poor drainage, the salt is
deposited in the soil and slowly kills all but the most salt resistant
crops. Thousands of acres in California
have gone out of production due to salinity problems, and up to a million acres
are projected to be severely affected in the future. It is so bad in places that “…you can see the salt on the ground
like a dusting of snow.” (Reisner, 1993)
The Bureau of Reclamation’s
solution to this problem is to build elaborate drainage systems and expensive
desalinization plants. Rather than buy
out irrigated farmland that contributes the majority of the salinity problems
to the Colorado River for millions of dollars, the Federal government has made
plans to build the largest desalinization plant in the world at the U.S.-
Mexican border at the Colorado River, at a projected cost of 1 billion dollars
over the next 50 years. (Reisner, 1993)
Consequences of groundwater withdrawal
Groundwater
subsidence of up to 60 feet has occurred in some areas of the Central Valley,
although lower levels are more common.
One study in the valley found:
…subsidence in this area locally
approaches 30 ft. …The subsidence here started probably in early 1930 and was
caused mostly by an overdraft of the sub-Corcoran aquifer system. (Prokopovich,
p149)
Subsidence results from the compaction of soils due to
unnaturally high levels of groundwater withdrawal. This compaction of the soil decreases soil permeability and
reduces rainwater infill rates, further compounding the problem. Groundwater reserves collect slowly over
thousands to millions of years, yet are being used at rates that will result in
exhausted supplies within the next century.
Even as
far back as the 1950’s, unsustainable groundwater withdrawal was becoming a
major problem.
…in the San Joaquin Valley,
withdrawals of ground water generally equal or exceed the long-term
replenishment… Where withdrawals have exceeded long-term replenishment, the
ground-water levels have declined substantially… (Davis, p33).
Clearly
a balance must be sought between sustainability and economic viability. Even placing environmental considerations
aside for a moment, it makes no economic sense to use a resource faster than it
can be replaced.
Policies which focus on
conservation over more water projects are the most cost-effective solution,
requiring little infrastructure investment compared to further development
projects. New water projects should be centered
around improved water-use efficiency rather that potentially destructive
development projects.
Agriculture
Solution
It is
economically unfeasible to allow marginal lands to continue to be
cultivated. Lands requiring excessive
irrigation, or with high salinity content or drainage problems should be
gradually phased out of production.
Policies should be augmented to
lower government subsidies on water to make corporate farmers pay their fair
share. Under the 1992 Central Valley
Project Improvement Act, farmers are allowed to sell excess water to outside
buyers, in hopes that conservation will be encouraged. However, they are required to buy the water
at unsubsidized rates. The act also reallocates
water back to fish and wildlife areas, one of the first water bills to reallocate
water back to, rather than away from, a natural source. (Gleick, 1999)
Another
possible solution is to grow special crops on lands with high salinity
content. This is currently being done
in Israel, with salt resistant strains of wheat, tomatoes and corn. (Reisner,
1993)
Further
water conservation could be achieved by growing crops in partially treated
wastewater, a method already in practice on a small scale in California and
elsewhere in the world. (Postal, 1992)
Urban
Solutions
Many
utility companies have realized the economic benefits of conservation on their own. A major Southern California water utility
pays its subsidiaries $125 for each 1,000 cubic meters of water they save. So far the program has conserved 541 million
cubic meters, or about enough water to supply nearly 1 million homes
annually. (Postal, 1992)
Many of
these approaches require a complete reworking of the American “more is better”
mentality so pervasive within our society today. The age of uncontrolled growth
and limitless resources is over. We
have now entered into an age where wise, controlled growth is not an option but
a necessity.
A future
of stability can only be achieved by sustainable practices today.
-Davis, G.H., et al: 1964, USGS Water Supply Papers, 1618, p33.
-Gleick, P.: 1999, The World’s Water.
-Kondolf, G.M.: 1994, “Bedload Sediments in California
Rivers: Effects of Dams and Instream Mining on Fish and Bridges”, Geological
Society of America, 6 (26), p24.
-Prokopovich, N.P.: 1989, “Ultimate Subsidence Along Outside Canal in the San Joaquin Valley, California”, Bulletin of the Association of Engineering Geologists, 1 (26), p147-157.
-Reisner, P.: 1993, Cadillac Desert.
-Solley, W.B., Pierce, R.R,
Pearlman, H.A.: 1998, “Estimated Use of
Water in the United States in 1995”, USGS Circular 1200, p71.
-Templin, W.E.: 1998, “California- Continually the Nation’s
Leader in Water Use”, USGS- Water Resources of California.
-USGS: 1999, “California Wetlands- Overview”, USGS Water Supply Paper 2425.