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Show CONGRESSIONAL RECORD-IIOU8E. 2719 all inflow between the two joints. This loss is partially accounted for by diversions for irrigation at Laguna Dam and other points above. The available records for Little Colorado and Williams Rivers are too short to permit of reliable deductions as to the mean annual flow. The average annual contribution of these streams to the main Colorado has l>een estimated at 200.000 acre-feet for the Little Colorado and 7:"»,000 acre-feet for Williams River. Records have l»een obtained at several points on Gila River for periods of different length. The records for stations at Guthrle, Solomonville, San Carlos, and Kelvin have been assembled in the attached tabulation. Below the junction of the Salt there are records for one year near Sentinel and for three complete years In the vicinity of Dome. Records of several years' duration are available for Salt and Verde Rivers, and for periods of various length for San Francisco River, at Clifton; San Pedro River, near Fairbank; Santa Cruz River, at Tucson; Augua Fria River, near Glendale; and Hassayampa River, nettr Wagoner. Inspection of the longer records for Colorado River at Yuma and those for Salt and Verde Rivers shows that during the past 20 years there were two periods or groups of years of high run-off. The first group contains the years 1903 to 1909, and the second group the years 1915 to 1917. It is evident, therefore, that figures representing average annual run-off at points on streams in Arizona, deduced from a record of only a few years In length, may be subject to considerable error. Question 2. What percentage of the total flow of the Colorado River, originates above Lees Ferry, and how much below that pointt Answer 2. Measurements of the flow of Colorado River at Lees Ferry have l>een made since July, 1921. The total run-off at that station for the water year ending September 30, 1922, was 16,100,000 acre-feet. For the same period the flow at Yuma was 17,600,000 acre-feet, and at Topock, 19,000,000 acre-feet. Therefore, for that year 91.5 per cent of the total flow as measured at Yuma and 84.2 per cent of that measured at Topock came from above Lees Ferry. The mean annual flow at Yuma for the 20-year period 1903-1922 is 17,400,000 acre-feet. Therefore the water year ending September 30, 1922, was 200,000 acre-feet, or a little more than 1 per cent greater than the mean. From the above it appears that between 85 and 90 per cent of the total flow of the Colorado River originates above Lees Ferry. Before the Lees Ferry records were available a study was made for the Colorado River Commission of records col-lei ted at gauging stations above Lees Ferry and the conclusion reached at that time-March, 1922-that about 91 per cent of the run-off at Yuma came from the States of Wyoming, Colorado, and Utah. Question S. What part of the total flow of the Colorado comes from the Gila River? Answer 3. Records showing the flow of Gila River near the mouth are fragmentary. The Reclamation Service, however, has made an estimate of the total flow for the years 1903 to 1920, based on the available records and measurements of the Gila at or near Yuma. These estimates indicate an annual run-off of the Gila during 1903 to 1920 varying from less than 100.000 to' 4^500,000 acre-feet, with a mean of about 1,100,000 acre-feet, which is about 6 per cent of the mean annual flow of the Colorado at Yuma. Question 4. What are the dates of some of the highest floods in the Colorado River at Yuma and the flow in second-feet at the peak? Answer 4.. The maximum daily flow for each year during the period of record is shown on the attached sheets. The maximum recorded flow at Yuma was on January 22. 1916, when the mean flow for the day was 240,000 second-feet. It should be noted that this flood originated primarily from the Oil*, as. during the winter, the main Colorado River is at low stag*' The next highest flood occurred June 8, 1920, when the mean daily flow was 190,000 second-feet. This flood came from that part of' the drainage area above the Gila. In general, winter floods at Yuma come from the Gila and summer floods from the Colorado River above the Gila. Question 5. What are some of the low-water dates of the Colorado River at Yuma and the minimum flow in sm-ond-fcetf Answer 5. The minimum daily flow for each year of record is shown on the attached sheets. The minimum recorded flow at Yuma occurred January 16, 1919, when the mean flow was 1,800 second-feet. Question 6. During what periods has all of the flow of the Colorado been diverted into the Imperial Canal, having the river dry in Mexico below the intake? Answer 6. The Reclamation Service has obtained the following Information from the Imperial irrigation district: " In 1915, from September 20 to September 27. and again on October 2 and 3, all the water of the Colorado River was diverted into the Imperial Valley canal system, in spite of which an actual shortage, though not severe nor disastrous, existed there part of that time. In 1919 there was another shortage, the entire flow of the river during the period September 2 to September 14 being diverted Into the canal system. " During this period the mean flow was 3,325 second-feet, the usual diversion at this time of year being 5,000 second-feet Under date of October 31, 1022, a report In this office shows that the entire flow of the river had again been diverted, the river having been dry below the heading since October 2 and the mean flow for the period October 2-31 was reported at 3,800 second-feet. " This is the third time, so far as known, that the entire low-water flow of the river has been actually diverted into the valley, but at least one other year of record, 1902, had a minimum and mean flow for the month of September so low that the entire flow would not have satisfied the demands of the lands now under irrigation in Imperial Valley." Question 7. What are the dates of some of the highest floods of the Gila River at Yuma and the flow in second-feet at the peakf Answer 7. The Reclamation Service has recorded the following floods on Gila River of over 50,000 second-feet: Discharge of Gila at mouth. Date. Second-feet. February, 1891----------......_____________________________105,000 Mnrcb, 1905----"2I11"IZ1"1IZ11I2Z1IIZ~"2 21 95*000 November 1905_________________________ ^ " 95 000 Feb. 8. 191K___.......................I 80 000 Jan. 22. 1916-.................II____ZZZZZZZZZZZ 200 000 Jan. 31, 1916______________________________ _ 141,000 Not. HO, 1919................_.......... "Till------- 72 600 Feb. 25. 1920-___________.........____IIIIIIIIIIIIII 95.000 Question 8. During what part of the year it there usually no water flowing from the Gila into the Colorado River? Answer 8. The Reclamation Service has recorded the Gila as having been dry at Its mouth during entire months, as follows: Yean. May---------...................................____________ 8 June____________.___________________.....__.___„____ _ IS July---------......-------------....................----------------- 11 August------------------------------------------------------------------------ 6 September____________.________________»______________.- 8 October___________________________________________„____ 9 November_______-_________.________...___________„_______ 8 December_______________________________„___________________ 8 Question 9. Have both the Gila and Colorado Rivers been in high flood at the same time? Answer 9. The records show no periods when both the Colorado and Gila Rivers were In high flood at the same time. During three Gila floods there were considerable flows in the Colorado above the Gila, as follows: Date. March 20.1005... January 22,1910 April 20, 1917.... Yuma Peak. 111,000 VO, 000 70,000 Colorado. 16,000 40,000 30,000 Oil*. 96,000 300,000 40,003 Question 10. When has the Colorado River broken into Imperial Valley, and when were these breaks in the levees closed? Answer 10. The Colorado has " broken into the Imperial Valley " from August, 1905, to November 4, 1906, and again from December 7,1906, to February 10,1907. (These dates have been obtained from papers by C. B. Grunsky, entitled "The lower Colorado River and the Salton Basin," published in Transactions of the American Society of Civil Engineers, *vpl. 59, pp. 1-50, and by H. T. Cory, entitled " Irrigation and-river control in the Colorado River delta," published in Transactions of the American Society of Civil Engineers, vol. 76, pp. 1204-4571.) Question. 11. How many acre-feet of water were poured into the Salton Sink by each of these floods? Answer 11. There is no exact record of the total flow of water to the Salton Sea during these breaks, but it is approximately the same as the total flow at Yuma for the same periods. The recorded run-off at Yuma during the first period was about 22,000,000 acre-feet and during the second period about 2,500,000 acre-feet. Question 12. How many acre-feet of silt are deposited in the Colorado River delta each year? Answer 12. The All-American Canal Board, in rejK>rt published in 1920 (pp. 24-26), estimates the average quantity of silt carried in suspension annually at Yuma at 90.000 acre-feet 11ml the bexl load at 12,000 acre-feet, making a total load of silt of 102,000 acre-feet. |