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Show PART II PRESENT STATUS OF IRRIGATION Methods used in collecting and reporting data differ among the many canal and reservoir companies. Because the available information lacks consis- tency and is relatively incompatible, a regional analysis of diversion records is not considered practical. The most consistent data on irrigation diversions are those of the Census of Irrigation. The Census of Irrigation is conducted by the Bu- reau of the Census decennially and was last taken in 1959• Census data regarding irrigation operations were obtained from irrigation organiza- tions and with few exceptions included only organizations which sup- plied water to two or more farms. Table 5 gives Census of Irrigation data for surface water conveyed by irrigation organizations to farm irri- gation water users in the Upper Colorado Region. Information as to the substantial quantities of water diverted by individuals is not available. Since the total amount of water diverted for irrigation is unknown, the Census data are only an indication of the relative amounts of water di- verted by irrigation organizations within the subregion and States. Table 5 - Amounts of surface water conveyed by irrigation organizations to farm irrigation water users, 1959-i' _______________________(Unit--1,000 acre-feet)______________________ Hydrologic Ari- New Subregions_____zona Colorado Mexico_____Utah Wyoming_____Total Green River 270.5 739.1 I18.1 1,^27.7 Upper Main Stem 1,8^2.9 25.3 1,868.2 San Juan- Colorado (D)______3 W.I______135 .fi 55*9 ________535.^ Total (D) 2,^57*5 135 A 820-3 *H8.1 3,831.3 l7 Source:U.S. Census of Agriculture, 1959> Vol. Ill, Irrigation of Agricultural Lands, State Tables 1. (includes only that water con- veyed to two or more farm irrigation water users.) (D) Data not available. Ground water accounts for about 1 percent of the supply for irri- gation in the Region, derived from pumped or flowing wells, and directly from springs. The estimated average acre-feet of withdrawal and consump- tive use of ground water used on irrigated lands during the period 1961 to 1965 are shown in Table 6. Further details regarding ground water are found in Part V of Appendix V, Water Resources. Reservoir storage is essential for effective water control as the streamflow varies both on a seasonal and year-to-year basis. Peak flows occur during the spring and early summer months as a result of melting snow. 23 |
