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<br />o <br />':' ) <br />) <br /> <br /> <br />U\ <br /> <br />W <br /> <br />DEPLETION IN FLOW OF COLORADO RIVER AT <br />LEE FERRY DUE TO MAN'S ACTIVITY IN COLORADO <br />RIVER BASIN IN COLORADO <br /> <br />Fundamental Facts <br />\ <br /> <br />1. MAN CANNOT DESTROY WATER. . He can change its form, its <br />location from one drainage area to another, and its use. but it still <br />exists somewhere. He can turn it into steam and the sun can evapo- <br />rate it but it comes back to earth either as dew, l"ain or snow. <br /> <br />a'. Nature uses water in 1:11e development of all vegetation but requires <br />a relatively small quantity to pr.oduce the actual f1"w.t and fiber that goes <br />into the makeup of whatever sort it is. <br /> <br />3. There i,. a certain amount of water evaporated or transpired by grow- <br />ing vegetation as evidenced by the cool air felt passing to the windward <br />side of an alfalfa field on a hot summer day; but if one walks through that <br />same field early the next morning. one~ lower extremities are drenched <br />with water from the dew condensed on the plants during the night, the <br />amount of which might well exceed the amount transpired from the leaves <br />during the day. <br /> <br />4. The time 'that surface water used in the irrigation of crops is exposed <br />to sun and wind, is d.etermined by method of application. type of soil. ele- <br />vation above sea level, etc. <br /> <br />Take alfalfa for an instance. Probably the maximum number . of a.pplica- <br />tions needed in the Colora.do RiVer basin in Colorado is 5 and the maxi- <br />mum hours applied to each irrigation to any particular area is 6 hours. <br />so that surface water is exposed to the elements a total of 30 hours. but <br />15 of these tiours would be at night when there is no evaporation and a oer- <br />tain part of the 15 hours of daylight would be during the time the alfalfa <br />shades the ground. <br /> <br />Where grain is irrigated by flooding. about three irrigations are needed <br />with about four hours exposure or lZ hours altogether, with 6 hours of <br />this at night and as a rule the 6 hours of daylight would be while the grain <br />shaded the ground. <br /> <br />'C,'" <br /> <br />In furrow irrigation of corn. beans. beets, potatoes and other row'crops. <br />the surface water exposed to the elements in furrows would probably not <br />average more than lZ hours for beans and like crops; ZO hours for beets. <br />pot atoes, etc., with about 1/3 of the time being at night. Also the good <br />farmer will cultivate after every irdgation. until the plants get too large. <br /> <br />-1- <br />