Water Supply in Southern California

[Apart from the sky(!) - it can rain a lot in the rainy season here, which is why there's tons of concrete in LA for flood control as when it comes, it can come in huge quantities. However, it's nothing like enough to support the huge and still growing population of Southern California]

Everyone who lives here should appreciate just how it is that we are able to live in a desert that is drier than Beirut, yet still maintain green lawns and golfcourses and have enough running water to serve the population of the 2nd largest metropolis in the whole of the US. It took me a couple of years to think about it, then I started reading books about it, and now it's turned into a new interest for me, investigating water projects. The definitive work on water in the Southwest is Cadillac Desert (ISBN: 0140178244) by the late Marc Riesner. It was also made into a PBS series. Southern California owes its tenuous existence to some spectacular feats of engineering, which bring water in from remote sources hundreds of miles away. Before these were constructed, the city of LA was reliant upon the intermittent flows of the Los Angeles river which effectively limited population growth.

There are 3 main water sources coming into the Southern California serving different geographic regions:

Los Angeles Aqueduct - constructed in 1908-1913

Colorado Aqueduct - constructed around 1940

California Aqueduct- constructed in the 1970s


Los Angeles Aqueduct

William Mulholland, an Irishman born in 1855 was the first visionary who could see that if only a reliable source of water could be found, it would put the fledgling city of Los Angeles on the map. He came to the US in 1874 from Ireland, and took a job as ditch-digger with the Los Angeles City Water Company a couple of years later. He rose through the ranks of the Water Company and taught himself engineering by studying books in his spare time. He was a driven man, and rose up the corporate ladder over the next 30 years. By 1904 he had reached a position of considerable influence, and had overseen the rebuilding of the entire water system of the city - the plans of which he kept largely in his head. Despite efforts to make people conserve water, he recognized that the city would soon run out of water at its current growth rate, and would need a supplemental supply. He had heard about a remote valley with a river flowing through it, and considered that this might possibly be suitable as the source he was looking for. This was the Owens River, in the Owens Valley, some 200 miles north of LA, which was fed from snowmelt from the Eastern Sierras. He envisioned diverting this river by means of a 233 mile long aqueduct to bring it to Los Angeles.

Once he had seen the feasibility of the project, in one of the greatest scandals of all time, Mulholland went off with his friend Fred Eaton by horse and cart across the Mojave desert, buying up strips of land, all the while maintaining that their motive would ultimately be of benefit to the prosperity of the poeple in the Valley. They were in fact deceived in two ways. First, they learnt the plan for the aqueduct to divert their valley water to the city of LA which would surely deplete their own irrigation supplies. Second, the water, so they were assured, was originally intended for irrigation purposes in the as-yet-developed San Fernando Valley, just north of Los Angeles. A consortium of powerful industry Barons in Los Angeles, including Harry Chandler, who then ran the LA Times were in on a scheme with Fred Eaton and Mulholland, and they bought up vast tracts of land in the San Fernando Valley, which, without water were pretty cheap. As soon as water was available to this land via the newly-built aqueduct, the land could be sold for many times the price for housing. The money was raised by a bond issue and construction of the "Los Angeles Aqueduct" started in 1908. Most of the books focus on the politics and scandal of the Aqueduct paying little attention to the engineering and the actual process of constructing it, which I find the most interesting. I'd love to get my hands on some drawings for instance, to see some of the obstacles they had to deal with.

Open Aqueduct at Cottonwood The smartest thing about the LA Aqueduct is that it manages to go the whole distance under gravity, and in fact actually generates power at 5 plants along the way. You can see the Aqueduct any time you drive along highway 14 north of Mojave, and along highway 395 - many Southern Californians drive this route up to Mammoth Lakes for skiing, many I'm sure unaware of what they are passing. It diverts the flow of the Owens River just north of Independence. While in the Owens Valley, the aqueduct is mostly a concrete ditch and for much of the length it is set into the foothills of the Eastern Sierra Nevada Mountains, and it's extraordinarily level. In fact it's dropping 18" in a mile at this point - preserving the height for as long as possible.

This ends up in Haiwee Reservoir, which is about 7 miles long, and visible to the east of Highway 395 south of Olancha. As the water leaves Haiwee Reservoir, it generates power at Haiwee Power Plant, then passes in pipes all the way to Fairmont reservoir.


Aqueduct pipe at Jawbone Canyon From time to time it pops out and dives down then up various canyons. The most spectacular of these "syphons" is at Jawbone Canyon, where they had to use extra thick pipe to deal with the extra water pressure at the bottom of the drop. In this picture of Jawbone canyon, the water runs up that hill! I found a place near Red Rock Canyon where there was an air vent, and you could look down and see the water running by.

The Aqueduct continues past Lancaster in the Antelope Valley to Fairmont Reservoir.This spot is also pretty close to the California Poppy Reserve. From here, it goes via an intake pipe through 10 miles of the Elizabeth Tunnel, into San Francisquito Canyon. I went out to visit Fairmont Reservoir one day, and came to appreciate why it was that the Elizabeth Tunnel was the first part of the aqueduct built: the whole viability of the project depends on that tunnel, since it has to carve through the mountains, even under Elizabeth Lake! It was bored from both ends simultaneously and set records in its day for speed of tunnelling. It then arrives in San Francisquito Canyon, where two of the power plants are located. Outside Power Plant number 1, is a collection of aqueduct memorabilia. See here for pictures of San Francisquito Canyon.

This was also the scene of the San Francisquito Dam disaster in 1928. Recognizing that local storage of water close to the city would be very desirable for dealing with peak demand and to cater for emergencies, Mulholland had constructed a dam in the Canyon for this purpose to create a storage reservoir. Unfortunately the location was wholly unsuitable geologically for a dam and it failed on March 12th 1928, demolishing several villages in its path, killing hundreds of people. The floodwaters eventually reached the ocean at Oxnard some 5 hours later. Mulholland eventually accepted full blame, and his career was over. He died in 1935.

End of the two aqueducts at the Newhall Pass

The end of the aqueduct is a familiar site for commuters heading north on Interstate 5, just before the Newhall Pass. Here you can see the original "cascades" which sometimes has water running down it. This was the original outflow from the aqueduct. Much of the time most of the water flow is in the adjacent pipe, since this way it maintains pressure to generate a small amount of power at the Van Norman plant where the water is treated prior to delivery to customers. On the day I took this picture, the cascades were dry, as construction workers were at work on the channel.

There are a couple of important later additions to the original LA Aqueduct. As early as 1912, even before the LA Aqueduct had even opened, it was planned by Mulholland that the flow from the Owen's River could be supplemented by constructing an additional section of aqueduct further north in the Owens Valley which would tap the streams feeding Mono Lake, some 30 miles north of Mammoth Lakes. Construction of the Mono Craters Tunnel took 6 years, and was completed in 1940. The tunnel dumps water into the head of the Owens River at Long Valley.

In addition, a second aqueduct, simply known as the Second Los Angeles Aqueduct, was completed in 1970 to supplement flows south from Hiawee Reservoir. This is also easy to see, but the route it takes is much less exciting - a function of economics. It essentially runs parallel to the original aqueduct but does not try to do it all by gravity - some pumping is involved. This pipe is gleaming white, whereas the original one is mostly black. This explains the higher cascade and pipe you see at Newhall from I-5.Second LAA at Jawbone


Owens LakeThe water taken from the Owens Valley has had a negative effect on the environment. The natural inflow from the river into the 316 square mile Owens Lake, diverted to the aqueduct, caused the water level to start dropping the same year as diversions begun. On all maps this is indicated as Owen's Lake (dry). The lake has no natural outlet, so the levels of salts such as sulphates, carbonates and chlorides had become concentrated. With evaporation, clouds of these salts over the lakebed in certain weather conditions causes one of the worst pollution problems areas in the whole USA.

The water level at Mono Lake also gradually started to drop after diversions began. This started to expose the famous "tufa towers" which are made of the various salts dissolved in the very saline lake. If you have a copy of the LP of "Wish you were Here" by Pink Floyd, the inner sleeve has a picture of a man diving into Mono Lake. It clearly shows the extraordinary Tufa Towers. Mono Lake is an important staging point for migratory birds. The sinking water level threatened to upset the area's ecosystem. A group of students, led by a gentleman named David Gaines, sought to protect the area. In a landmark trial in the 1980s, it was recognized that the environmental impact was enormous, and the DWP was forced to agree to limit diversions. The lake level has stabilized over the last few years, and I believe is now rising again.

See here for an elevation diagram, which I snapped when the DWP had an exhibit about the aqueduct at the Gene Autry Museum.

Colorado Aqeduct

It's much harder to find good information about the Colorado Aqueduct as the stories are not so sensational. It had been Mulholland's idea that the "next" source of water might be to tap it from the Colorado river. The Metropolitan Water District who owns and operates the Colorado River Aqueduct has a page full of good facts here. The entry point of the system is Lake Havasu in Arizona, which is formed by Parker Dam. From here it gets pumped up over mountains in 5 stages up to a height of 1800ft. The water ends up in Lake Matthews in Riverside County some 242 miles later.

California Aqeduct

Most recently constructed is the California Aqueduct, which not only brings water to Southern California, but an irrigation supply to the Central (San Joaquin) Valley as part of the State Water Project. The aqueduct is approximately 444 miles long taking water from the Feather River north of the Bay Area. Most of the time this is a wide, concrete lined ditch. At the southern end of the Central Valley, the water is pumped over the Tehechapi Mountains by massive pumps that lift it in 4 huge pipes up 1900'. This is the Edmonston Pumping Plant just near Interstate 5, as it climbs the Grapevine.

In the Antelope Valley, the aqueduct is again in a concrete ditch, and can be seen under the 14 freeway to the south of Lancaster. The aqueduct eventually flows into Lake Perris in Riverside County.

Here's a statistic: the State of California consumes more energy pumping water around, than some other states use for their entire energy needs.

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