Los Angeles Water Supply Siphons Itself Across Mountains
Next to New York’s Catskill water supply comes the new water system now under construction for the city of Los Angeles. Cal., both in respect to magnitude and cost. The country where Los Angeles is located was originally a desert, and to the observer it appears that the sea has recently receded, leaving only a plain of sand. Going into the desert the people began to build and arrived at the point where it was necessary, in order to keep up the progress of the town, to cast about for a water supply to meet its rapid growing needs. It might have been possible for the city to invade neighboring irrigation districts, and, by exercising her right of eminent domain, to take irrigation water for domestic uses, but this would have destroyed fruit farms worth more than $1,000 per acre. The alternative adopted was a remote mountain source. The eastern slope of the Sierra Nevada range, situated in central California, between Owens and Mono lakes, for a distance of 125 miles drains through the Owens valley into Owens lake, which has no outlet ami which covers an area of 100 square miles, from which there is an annual evaporation loss of 7 feet in depth. The northernmost part of this basin adjoins Yosemite National Park. Along the crest there are 40 peaks, having an elevation in excess of 13,000 feet, of which the highest, Mount Whitney, attains 14,500 feet. This is the source of supply selected several years ago by the city of Los Angeles to be tapped by the longest aqueduct in the world. So the city determined to construct an aqueduct over 200 miles long through mountain and desert. The aqueduct consists of a scries of six storage reservoirs and 215 miles of conduit. The largest reservoir site is on the main stream at Long Valley, with an elevation of 7.000 feet, about 50 miles above the point where the aqueduct diverts the river. Here, with a dam 160 feet in height. 340,000-acre feet of water may be impounded, or enough water to cover 310.000 acres 1 foot deep, which is 28,000acre feet less than the capacity of the Ashokan reservoir now being constructed by the city of New York. Fifty miles below Long Valley reservoir site, the main channel, with a capacity of 900 cubic feet per second and a width of 65 feet on the bottom, diverts the river and various tributaries as they are passed, discharging into the Haiwee reservoir 60 miles below the intake. This 90,000 second-foot canal will carry all ordinary summer flood waters caused by the melting of the snow. The Haiwee reservoir, with a capacity of 64,000 acre feet, will regulate these flood waters into a uniform flow of 400 cubic feet per second, of 258 000.000 gallons daily—a truly vast supply. IT is difficult to explain to those inured to eastern humid conditions the obstacles that have to be surmounted in order to conquer a desert sufficiently to build across it a great public work of this nature. The mountain torrents proceeding from the eastern face of the Sierra in Owens Valley have heavy grades and offer unusual opportunity for the development of water power. Preliminary to construction, three water plants were built on these streams, having an electrical output of 3.500 horsepower. The city proceeded with marked diligence and ability to acquire the necessary private lands and water rights. When the public was informed, it endorsed their action by a vote of 9 to 1, and this ratio of public confidence has been sustained through two subseouent campaigns, the people voting first $1,500,000 for the purchase of lands and water rights, then $23,000,000 for hydraulic work and $3,500,000 for waterpower installation.
An idea of the magnitude of this work may be obtained from the illustrations on this page, which this magazine is permitted to use through the courtesy of Collier’s Weekly. Notice riviting of steel plates in foreground. This is without doubt the most remarkable nipe line in existence Tt is 8 000 feet in length, has a diameter from 7 feet 6 inches to 10 feet, and at its lowest point the water pressure is 350 pounds to the square foot. Here the thickness of the shell is 1 1/4 inches. There is a difference of 850 elevation between the inlet and the lowest noint in the siphon. Colliers Weekly in another illustration, shows a 50-mule team hauling a section of the immense siphon into the Jawbone Valley. It is expected that the system will be ready for use by the first of April. The total cost of the project is approximately $30,000,000.