Report of the Special Committe of the United States Senate on the Irrigation and Reclamation of Arid lands

              STATEMENT OF W.A. GLASSFORD, SECOND LIEUTENANT,SIGNAL OFFICER, SIGNAL CORPS, U.S. ARMY, OF PRESCOTT.Rain fall in Arizona, and it's effect on irrigation and water storage, with description of some favorable points for storage reservoirs.General features of Arizona.-No portion of the Union probably presents such favorable conditions for the artificial catchment of water for agricultural and other purposes as does Arizona. In its great area, nearly double that of the six New England states, are presented physical features peculiarly adapted to the construction and maintenance of an immense system of irrigation based on the storage of water by artificial reservoirs, and the supply of which it will be the endeavor of the writer to show is abundantly provided for by rain-fall.Were it possible to obtain a birds-eye view of the Territory, the observer would see spread out before him an area equaling Italy in size, consisting of a series of mountainous plateaus, ranging in height from 7,000 feet in the northern part of the Territory, to a few hundred feet in the southwestern portion. Of these plateaus those of the north will be found interspersed with the mountain chains and deep cañons. In some places volcanic cones rise over 5,000 feet above the plateaus, while cañon gorges are cut deep below. To these characteristics the plateaus of the southwestern portion of Arizona present strong contrasts, consisting as they so of level valleys, mesa or table lands, gradually sloping off towards the Gulf of California. Some of these are basins of what have been, at comparatively recent periods, immense inland seas. In places the loss of altitude is so rapid that immense cañons have been cut by erosion through the mountain chains and plateaus, and immense basins have been formed along the water-sheds of all the permanent streams. These cañons and basins are of great depth and area, and present unrivaled facilities for the construction of a system of artificial reservoirs similar to that established by the British Government in India, where the Himalayas present much the same characteristic features. The streams, which in the north flow through cañons whose precipitous sides tower thousands, of feet above the surface of the water, as they reach the southern mesas roll sluggishly along, with barely sufficient fall to prevent their sinking in the sand.It is in the valleys along the latter portions of the rivers of Arizona that are to be found rich alluvial lands unequaled in fertility and productiveness.The areas of these land in Arizona are variously estimated from 6,000,000 to 10,000,000 acres, or an area surpassing all of Massachusetts, Connecticut, and Rhode Island, or Belgium, and nearly equaling Switzerland. The vastness of these areas can scarcely be realized from the mere mention of the figures, but their extent can be appreciated when it is remembered that the entire area of such land susceptible of reclamation of the Rhone in southern France is less that 400,000 acres; Spain does not equal this, while the famous Deltaic provinces of lower Egypt possess but about three times this area, and India, the oldest settled of all lands, has but about five times as much as France under cultivation through irrigation. Irrigation and water storage in Arizona.-The almost level and uniform surface of these lands in Arizona makes this reclamation by diversion of water upon them easy when the water is obtainable, Many streams are now used for irrigation by diverting the water canals. The lands thus reclaimed are close along the banks of streams, where the diversion is accomplished by gravity. So profile and various are the productions of the land already reclaimed that canals and ditches have increased so as to go far to exhaust the available permanent flowing streams. This is especially observed when the stage of supplying streams is at the minimum, occurring during years of scanty rain-fall.The utilization of water for arable land has forced in some places an approach to the exhaustion of the water supply that can be depended upon during years of extreme drought, at least gone far to alarm the rights held by prior appropriators. Above the existing canals is more land, and in some localities vast quantities, that only want the water brought upon it. This conducting of water to higher levels involves in most cases the necessity of either very long canals, because taken from a point higher up the stream, or storage dams by which a higher level for the exercise of gravity is obtained without increasing the length of canal. We thus see that an increase of the amount of water by storage projects in favored by two considerations: First, tow widen the area of land possible to be reclaimed; and, second, to secure sufficient water during seasons of drought. Such storage being necessary to the general welfare, the question of the practicability of impounding water naturally arises.The solution of this question is found primarily in an accurate determination of the depth of the annual rain-fall, with both the maximum and the minimum that may be expected in the district under consideration; also any peculiarities of its distribution.