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<br /> <br />CHAPTER VI <br /> <br />HYDROLOGY OF THE COLORADO <br />THE INCREDIBLE SHRINKING RIVER <br /> <br />A few weeks after Congress passed the 1928 Act, Congress passed a joint resolution <br />authorizing and directing the Secretary of the Interior to appoint a board of five eminent engineers <br />and geologists to study and report on the proposed Boulder Dam alternatives. 147 <br /> <br />The commission was chaired by Major General William L. Sibert of the U.S. Army <br />Engineers. The Sibert Commission studied the geology, safety, economic and engineering feasibility <br />and hydrology of the proposed sites. In November 1928, the commission issued its report. In addition <br />to recommending the Black Canyon dam site, the report addressed the water supply ofthe Colorado <br />River. <br /> <br />The report was higWy critical of the hydrology and by implication critical of the assumptions <br />made by the negotiators of the 1922 Compact. The commission reported: 148 <br /> <br />"A record of gauge heights for the River at Yuma is continuous from <br />April 1878, but no actual current meter gaugings were made at the <br />station unti11902. In 1902 the Hydrographic Branch of the United <br />States Geological Survey established a gauging station at Yuma <br />which was maintained until the close of 1906, when the station was <br />taken over by the United States Reclamation Service in connection <br />with the operation ofthe Yuma irrigation district. <br /> <br />In 1909 the Yuma gaugings were estimated by an engineer of the <br />United States Geological Survey as probably too large, varying from <br />nothing to 15 percent, and he suggested improved methods, which <br />were, however, not adopted unti11918 and the best modem methods <br />were not installed until January 1926. The opinion was also expressed <br />to the board by officials at Yuma in charge of the gauging work that <br />the measurements made prior to 1926 were too high an estimate." <br /> <br />The report went on to draw the following conclusion: <br /> <br />"One of the most important facts shown by these estimates is the <br />existence of a long dry period in the Colorado River flow prior to <br />1906. This low period is clearly shown by an inspection ofthe Yuma <br />gauge record for that period. Further investigation of this matter has <br />convinced this board that the flows of the Colorado River as <br />determined by the gaugings from 1906 to 1927 are materially higher <br /> <br />14745 Stat. 10 11. (1928). <br /> <br />148House Document 717, 80th Congress, Second Session pages AI97-198. <br /> <br />Page -65- <br />