File:The future water supply of San Francisco; a report to the Honorable the secretary of the interior and the Advisory board of engineers of the United States army (1912) (14586478099).jpg

Identifier: cu31924004975805 (find matches)
Title: The future water supply of San Francisco; a report to the Honorable the secretary of the interior and the Advisory board of engineers of the United States army
Year: 1912 (1910s)
Authors: Spring Valley water company, San Francisco
Subjects: Water-supply
Publisher: (San Francisco, Printed by the Rincon publishing company
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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ream bed, so that verylittle water will escape into Laguna Creek andbe wasted. Exception may be taken to thismethod of conservation because of fear that thegravels may become clogged up with silt, but letit be borne in mind that in the first place thereis not a large amount of silt in these waters,and in the second place, their velocity is abruptlychecked when they enter Arroyo Valle Reser-voir, and they will drop whatever silt they carryinto the bottom of this reservoir, before beingconducted to the gravels. Furthermore, the Arroyo Mocho has beenspreading out over the gravels near Livermorefor untold years, very rarely running throughto the Laguna Creek, and there is no evidenceof a decrease in the absorptive powers of thesegravels by reason of its action. This Is Being Done in San Ber-nardino Valley. This practice of spreading flood waters overgravels has been in progress in San BernardinoValley, in Southern California, for several yearspast. Just below where the flood waters of the
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THE CALAVERAS A GREAT PRODUCER. 31 Santa Ana Kiver debouch from the mountains,they are diverted by means of dam and canalsand spread over the gravels of the stream bed,much in the same way that broad irrigation ispracticed. In this manner great quantities of flood watersare absorbed by the gravels, increasing the under-ground supply from wells for a distance of sixtymiles below. Officers of the various companiesprofiting by this work, state that the increase isvery marked, and that they are repaid a thousandfold for the expense incurred to spread thewaters. It is probable that the velocity with which thewater enters the gravels in this case is about thesame as it will be in the Livermore Valley. Ivisited the site of this work last year while thework of spreading water was under way and sawhow greedily the gravels drank up the water.Even where water is spread in soils it is ab-sorbed with surprising rapidity. In Imperial Valley, while Chief Engineer ofthe California Development Company

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