With a population of 39 M people, California is by far the most populous state in the US
with Greater Los Angeles being the second-largest urban region in the country. And the water
needs are high, as California has a strong economy, with a with a Gross State Product
of $3.2 trillion USD in 2019. To better illustrate this ﬁgure, it is worth comparing it to
entire nations. California alone would be the ﬁfth largest economy in the world, just
ahead of India. And the economic activities extend across all sectors. Industry and ﬁnances,
media and ﬁlmstudios, the information industry in Silicon Valley, trade, as well as agriculture,
which withdraws high amounts of water. California is producing the highest yields in the US.
All these factors lead to an enormous demand for water. In total numbers, California is
the largest consumer of water in the United States. In this video, we want to understand
how this supply is maintained and what some future challenges might be.
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First, let's take a look at Californias geography. Note that this is a map with extremely exaggerated
topography. There are several signiﬁcant Mountain Ranges across the state. Northern
California has the Klamath mountains. Along the Paciﬁc Ocean there are the Northern
and Southern Coast Ranges. And to the south we ﬁnd the Transverse Ranges and the Peninsular
Ranges. To the east is Sierra Nevada, the highest mountain range in the state. This
mountainous landscape contrasts with the large ﬂat area that characterises the interior
of the state, the Central Valley. At the same time, there is the Colorado Desert as well
as the driest desert in North America, the Mojave Desert. So geographically, California
is a very diverse state. It is home to both the highest point of the contiguous United
States, Mount Whitney, and the lowest point, Death Valley. And the many mountain ranges
are crucial to the water supply as about 30 percent of California's water comes from Snowpack.
For example, the snowfall in Sierra Nevada supplies large parts of the Central Valley
with water. The Central Valley consists of the Sacramento Valley and the San Joaquin
Valley, named after these two important rivers in the state. With the Sacramento river being
the larger source of fresh water as it receives approximately two thirds of northern California's
precipitation. These rivers eventually join and ﬂow through the Carquinez Strait into
the Bay of San Pablo and San Francisco. The rivers delta is an important source of fresh
water withdrawal in the state. The Central Valley Project uses a series of dams and artiﬁcial
canals to divert both rivers to supply the entire Central Valley. These canals are essentially
artiﬁcial rivers that help distribute the water. This allows better water management,
prevention of ﬂoods and droughts, and renewable power generation. It even enables a more effective
use of land, as dams allow large cities to grow close to river valleys without the risk
of ﬂood during spring. And thanks to the canals that distribute fresh water for agricultural
irrigation in the valley, the dry environment of the San Joaquin Valley, located a little
further south, has been transformed into arable land. But water isn’t just distributed within
the Central Valley. After all, the supply in the Los Angeles Area and San Diego is a
particularly big challenge. And nowadays, it is only possible thanks to enormous efforts.
When it comes to supplying the LA with surface water, 3 projects in particular stand out.
The Los Angeles Aqueduct, consists of two separate canals, that tap water from the Owens
River and its tributaries in the Owens Valley and then transports it to Los Angeles. But
diverting this water caused environmental damage. The Owens Lake was deprived of its
tributaries, which led to the Lake drying up. And at times, increased
withdrawal and additional canals also threatened water levels at Mono Lake, an important spot
for bird migration. Another large source of water is the Colorado River. Water is transported
to cities in Southern California using a series of partly above-ground and partly underground
canals. In certain parts, the water has to be pumped over higher mountain passages using
pumping stations. But the longest such canal project is the California Aqueduct. It transports
water from Clifton Court Forebay, in the San Joaquin River delta, all the way to the southern
part of the state. Along the way, there are considerable differences in altitude and the
water has to be pumped from many places using a lot of energy, especially over the Tehachapi
Mountains that must be crossed on this route. At the Edmonston Pumping Plant, the water
is raised an entire 587 meters or 1926 ft. At other places the water drops abruptly.
Here, hydropower stations are used to recapture as much energy as possible. But it becomes
clear that enormous efforts and costs are necessary to provide for the densely populated
cities in Southern California. So it can be said, water from the Sacramento and San Joaquin
river is essential to the state's water supply. And their potential for providing water across
the state is increased by enormous infrastructure, for example in the Central Valley Project,
for enabling agriculture, or in the California State Water Project, for the drinking water
supply in southern California. Water for this region is taken from the river delta between
the Sacramento River and the San Joaquin, which is also used for the supply in San Francisco
and the Silicon Valley. In total, this river delta supplies around 25 million people, two
thirds of California's population, with drinking water. Of this, 67% is exported for use in
the Central Valley Project and 26% goes to the State Water Project. However it is important
that the withdrawal is strictly monitored. If not enough water ﬂows through the delta
into the bay, salty water from the Paciﬁc Ocean threatens to intrude the delta and reduce
water quality. Even in normal years, the water supply in the state is already strained, and
during droughts the situation gets extremely difﬁcult.. Another important source of water
is groundwater, which usually accounts for about 30 percent of the supply in a normal
year. But in years of intense drought, this percentage can rise to 60 percent or more,
a level of depletion that is not considered sustainable. Due to climate change, more extreme
weather events are to be expected, such as more frequent droughts, as well as extreme
precipitation events, which in turn can lead to ﬂoods. The 2012 to 2016 drought is considered
one of the most extreme ones in California's history and has brought many farms into crisis.
Water supply in modern California is only possible due to enormous efforts and large
achievements. While there have been many successes, these projects also cause damage to complex
ecosystems and habitats. And they create water conﬂicts between communities, as well as
between cities and farmers. In addition, many Native American tribal lands have been ﬂooded
in the past in favour of dam projects. Many measures are being taken, in order to use
the limited amount of precipitation in the state as efﬁciently as possible. This includes
dams, canals and increased usage of seawater desalination on the one hand and measures
to reduce water consumption on the other. Such as water meters in every home, restrictions
on private withdrawal, water recycling, and modern irrigation methods. However, further
improvements in all these areas will be necessary to achieve a sustainable water supply in the state
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