The Arizona sentinel., 1903-03-18
RESOURCES OF THE
 COLORADO RIVER.

DulI0Ulu NO. H, lSSueu Uy GII6
 agricultural department of the
 Territorial University, contains
 some valuable information of the
 Colorado river that is of particu-
 lar interest to the farmers in the
 valleys. The bulletin was com
 piled by Prof, Robert E. Forbes,
 director of the station, and can
 be had by addressing him at
 Tucson. The following briefsyn-
 opsis may be of interest to the
 general public:
 Approximately speaking, the
 Colorado river is 2000 miles long
 and drains an area of about 225, 900 square miles. The upper
 two thirds of this area is high
 plateau furrowed by deep can
 yons and ridged with great forest-covered mountains. The remaining third of the water shed is lower-lying desert couu- try, draining into the Colorado through the Little Colorado, Virgin and Gila rivers.
 Passing occasional floods, the river reaches its minimum flow between September first and March first of each year, at which time the flow is-about 4000 cubic feet per second. In March and April, from the effects of melted snows, the river begins its annual spring rise, and at tains its maximum early in June, at which time the flow may be safely computed at 50,000 cubic feet per second. The normal flow of the river, estimated on fragmentary data and resulting from an average runoff of about one and a quarter inches of ram fall from the watershed, is not far from 15,000,OOO acre feet annually, sufficient to irrigate nearly 100000 acres of agricul- tural land.
 The sediments contained by the Colorado river vary in ac- cordance with the quantity of the flow. During low water in January, February and March the average is 62 parts of sedi- ment to 100000 parts of water. In April the volume of sediment rises to 112 parts and in May and June to 374 parts, decreasing with the lowering waters of July and August to an average of 122 parts. The summer rain storms of September, October and No vember bring the silt to it's max imum of 2,072 parts, after which the quantity sinks to the normal | amount for winter waters, aver aging 151 parts in 100000 during the two months ending January 1 24. 1901.
 The average acre-foot of Colo rado river water for the year of observation (190O) carried 7,29I pounds of silt; at such rate four acre feet of water-about the average required to irrigate an acre of ground for one year, would contain 29,16O pounds of silt, or 67 pounds to the square foot, approximately one tenth of an inch of soil. On the basis of the determinations made in the |; university laboratory it is esti- mated, conservatively, that dur ing the year 1900 the river brought down 61, 100000 pounds of sedimentary material, which, condensed to the form of solid rock, is enough to cover 26. square miles one foot deep; or to make B square miles of dry alluvial soil one feet deep; or to make 164 square miles of recent ly settled, submerged mud one foot deep, reckoning the whole f amount of mud for the year to average 6.2 times the bulk of the solid sediment. With the aid of snch figures it is possible to un- f derstand the agency of this river l in shutting off with it's deposits $ that arm of the ocean which af- forwards became the Salton Ba- sin, and in creating great areas T of fertile delta lands along it's lower courses. f The fertilizing value of these T silts reside chiefly in the nitro gen they contain, although pot r