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) (14773232015).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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1898 to 1908and from 1910 to 1912, it was found that therun-off computations made from the Williamsdata were for the most part so unreasonablyhigh as compared with the rainfall that gravedoubt arose as to reliability of the results. Arecomputation of the data was therefore de-cided upon. Williams ComputationsAre Erroneous. It was found in checking the area of the ninecross-sections in the 200-foot course and of thesix sections in the 100-foot course from themaps of these sections made by or under thedirection of Mr. Williams, that the mean areaof the nine and the six sections area, respect-ively, at different gage heights was taken asrepresenting the area of the 200-foot courseand of the 100-foot course for corresponding^age heights. These areas were found to bein error as much as 25%, because in the origi-nal computation of areas for correspondinggage heights (the gage in both cases being atthe upstream section), the areas in each of thenine and the six sections, respectively, of the
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325 y J l^ ;!;■;.■ , ■.: ■ ) .■ . •■,; ;■;, ■:. : . ^.^ / 11 - - ■; D- y^ ^ IK? it?/flai f.9A S6J-rfJi. -re.re «ft.ii ■ .. \ \ x /■ ) / titJZ ^ c ^ yfmaa/-- J7/ 7SO TT Ar.. <,/■- a fif itsML HIHI at su usris~ nt k >k 1^ / y .y Oil <37 5ls ,nSi 61 X y I. • ^ ._,______ - / X i--.i-^-- \ y - - i - • v- — —k^ .^t - /••* , • E^ i-^T ^ ,, , ■ - /; It ^3/ 1 ir! 1 ■ 1 X I 1 ^ 77-f■71^6 ! 1 / 1 ■ r/ii.■jfi ■Sf.-3^-7 i \ ■:-X ~. /. - -\ itr- ^* ■ zr.r ;« 1 /■.■- ..!< TE -BZ4a if ..-■■■ \^-^ ^=: - .-•: )■: ~\ v^-- 1 Ii )xm i-^ -If REPRODUCTION OF THE UPPER POUR CROSS SECTIONAL AREAS USED BY WILLIAMS IN COM-PUTING THE FLOW OP CALAVERAS CREEK OVER THE 200-POOT COURSE. NO ALLOW-ANCE WAS MADE FOR SLOPE IN WATER SURFACE IN THIS 200 FEET. 326 KALEVIM

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