Utah exhibits [of the] State of Arizona, complainant, v. State of California, Palo Verde Irrigation District, Imperial Irrigation District, Coachella Valley County Water District, the Metropolitan Water District of Southern California, City of Los Angeles, City of San Diego, and County of San Diego, defendants, United States of America and State of Nevada, interveners, State of New Mexico and State of Utah, parties

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208 IRRIGATION INVESTIGATIONS IN UTAH. Toquerville and the latter 2 miles south of St. George. Southwest of St. George are the Virgin Mountains, 5,000 and 6,000 feet high; west are the Beaverdam Mountains, of about equal elevation. Through the gap between the two ranges, 20 miles southwest of St. George, the Virgin River has cut a canyon which separates this valley and that of the lower river in Arizona and Nevada. Below the canyon the watershed on the south is a continuation of the Virgin Range; on the north the river drains the southern slope of the Mormon Range. Both ranges reach elevations of 9,000 and 10,000 feet. THE AOBICtJLTUBAL SECTIONS OF THE BASIN. The irrigable sections of Virgin River Basin are scattered throughout the length of the river and its tributaries, from an elevation of about 1,300 feet at the mouth of the river to one of 6,750 feet on the headwaters. They are either entirely along the stream bottoms or on the contiguous bench lands. The area already devoted to farms is but a small percentage of that which could be farmed were water available for its irrigation. Varying in elevation and exposure, they furnish a.diversity of seasons and temperature, and consequently permit the growth of a wide range of products, from the apple and the potato in the higher, colder districts, to cotton and sorghum in the lower valleys. In these lower valleys, particularly in southern Nevada, the climate is such that this range of products could in all probability be widened to'include some of the subtropical fruits that thrive in California and southern Arizona. The unwatered irrigable areas are in general of the same character and present the same physical conditions as the watered areas. Of the unwatered areas the bench lands predominate. On the upper reaches of the stream no lands but these remain open, for there the narrow bottoms have been tilled almost since the first settlement in the basin. CLIMATE. The rainfall of the valley of Virgin River ranges from 3 to 4 inches at St. Thomas, Nev., 25 miles above the mouth of the river, to 10 inches or slightlv more, in parts of Washington and Kane counties, Utah. The most complete records available have been kept by the United States Weather Bureau at St. George,.Utah. These records show that for a period of nine years, from 1893 to 1901, the mean annual precipitation was 6.31 inches, and the mean annual temperature 57.6 degrees. The year of greatest rainfall was 1897, when 9.81 inches fell; and of lowest rainfall 1894, when only 3.55 inches fell. During this period the months of least mean precipitation were, in order, June, September, November, and May, and the greatest mean precipitation August, February, January, and March. The lowest monthly mean was 0.1 inch, in June, and the highest, 1.11 inches in August. There has been no year in the nine in which at least one month was not devoid of precipitation. In five months in 1901, four months in 1894, three months in 1898, two month:* in 1S93, 1895, 1897, 1899, and 1901, the total precipitation was not over 0.01 inch; in some of these months there was no precipitation. The greatest fall for one month during the period was 2.98 inches, in July, 1896. The months of lowest mean temperature during these years were, in order, December, January, February, and November,