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

page 209

AGRICULTURE UNDER IRRIGATION IN BASIN OF VIRGIN RIVER. 209 and of tho highest mean temperature, July, August, June, and September. The lowest monthly mean was 36°, in December, and the highest 81.1-, in July. The lowest recorded temperature for the period was lc, on January 2, 1901, and the highest 115°, on July 29, 1S9S. For the four years 1898 to 1901, 79 per cent of all the days were clear, 12 per cent were parti}* cloudy, 9 per cent were cloudy, and only 9 per cent rainy. From these data it is plain that in the valley of Virgin River the rainfall is light all of the year, but lightest the last of spring and the beginning of summer and in the fall; that the temperature is devoid of low extremes but reaches high extremes in summer; and that most of the days are clear. It is therefore a region well adapted to agriculture by irrigation. VIRGIN RIVEE. Virgin River is a stream of uncertain flow and shifting bed. In winter and early spring it is fed chiefly by the springs at its source, but in summer the principal supply is from the melting snows and heavy rains in the higher watershed. While there is always water in the river in its upper reaches, it is often dry in the lower end. The flow is torrential, the floods following either a heavy downpour of short duration or warm rains on the snow-covered plateaus of the watershed. The heavy downpours occur usually in July and August, and sometimes cause much damage to the farming lands along the river bottoms. Especially during the floods, but also in all but the seasons of venr low water, the river carries in suspension a large percentage of sediment, which not only fills the head gates and ditches along its course, but also makes the impounding of water in the channel of the river impracticable. The river bed is of shifting sand, offering a foundation for none but temporary dams. This sandy bed widens at the lower end of the river to several hundred yards, over which tho river spreads in a thin, sluggish sheet, causing a heavy loss of water through seepage* and evaporation. During the summer the river is not a continuous stream. No water passes from Long Valley, on East Fork, to the stream below, and the bed is dry4n the canyon below St. George. In the lower canyon springs again feed the river, but 40 miles below it once more becomes dr}' in the early summer-by Ma}' 15 in 1902- remaining so, except during a week or ten days after floods, until the cool weather begins in the fall. A number of gaugings of the river were made during the spring and summer of 1902, and a daily record of the depth was kept from March 20 to October 15 at the sulphur springs between La Verkin and Hurricane benches. At that point the river is confined in a rocky channel, but of not entirely even sides. The shifting sand in the bottom prevented using a fixed gauge rod, so that depths were measured daily. The table of daily discharge at this point is given in connection with a discussion of water titles oil pages 231, 232. 18189-No. 124-03-14