Arizona silver belt., 1905-04-20
Will Impound Water to lrrigate 10000 Acres in Fertile
 Salt River Valley
NATIONAL IRRIGATION TEST
Reservoir to Be 25 Miles Long. To Be Supplemented With Electrical Pumping Scheme to Reclaim 5O,00O Acres Additional
By II. Gilson Gardiner.


 ago the secretary of the interior let the contracts for the largest irrigation reservoir in the world,
 It is to be called the Roosevelt dam. Near it is new town, also called Roosevelt. Both are situated in Ari- Zona, about seventy miles above PhOe. nix, on the Salt triver, near It's junction with ronto creek.
 This dam is the main feature of one of the largest of the government irri- gation projects. | is located in can yon of the Salt river, just below it's junction with the small tributary above named. It will be 270 feet high, 2lO feet long, l65 feet thick at the base, and l6 feet thick on top,
 This dam will create lake 25 miles long and two miles in width-the larg- est artificial reservoir in the world. It will be constructed of broken range cyclOpean rubble' and Portland ce- ment. The stone of which it will be built will be quarried from the walls on each side of the canyon It i'd cen. templated that work on the structure shall be carried on continuously day and night.
 Electricity for night work will be furnished free by the government The waters of Salt river have been har. messed to au electric power plant which develops HOO horse power, by means Of turbine, under head Of 220 feet fall. The power thus dsyel- Oped runs cement mill aud does all the hOisting, drilling, digging, etc, for the construction of the dam.
 The cement mill is located about 1900 feet from the damSte, and has been equipped with all the most mod. ern machinery for making Portland cement Clay is taken from the ground within mile from the mill, and one corner of the mill stands on a bed of limestone, which is one of the princl- pal ingredients. Close at hand are the sand and other materials from which bricks, as well ss cement, may be made. The mill has a capacity of 300 barrels day. It is estimated that POO, 900 berisls of cement will be need. ed to ouilG the dam.
 Another very important adjunct to this big work is wagon road which has been built from Roosevelt tO Mesa Globe is the nearest town, 10 miles distant. Another road, three miles in length, was built, leading to the tim. Der in the Sierra Ancha, where about 100000 feet of lumber have been sawed for use in the work.
 Some idea of the difficulty encouu- tered in the construction of the road | to Mesa may be inferred from the fact | that in some places, where it tray erses the Salt river canyon, it is cut | through solid rock sixty or seventy | feet deep, while Fish Creek hill is | climbed at the base of vertical i cliffs 600 feet high, where rock cuts sixty and seventy feet deep and fills of an equal height were necessary. Some portions of the road cost at the | rate of S25,O a mile. During the | short period while it was under con struction 400, 900 pounds of freight were hauled over it.
 The waters of this Roosevelt dam will be controlled by the largest ny. draulic gates ever built, With their controlling mechanism, they will weigh S00,000 pounds. When the re- ServOir is full they will be capable Of diScharging 10000 cubic feet of water a second. They will regulate the sup ply of water in canals fifty miles away.
 fhe gates are to stand at the head of a 500fOot tunnel which has been driven through the side of the canyon, and through which the waters of the Salt and TontO rivers will be diverted while the dam is being built. It is estimated that the dam will be com pleted in about two years.
 The excess water from the enor. nous reservoir will be sent through pipes into water wheeles or turbines, and the power generated will be taken sixty or seventy miles distant to cen trifugal pumps, by which other water will be raised to higher planes in the Salt river valley. It is estimated that each horse. power developed will irri- gate ten acres, at distance of sixty miles. An area of no less than 50,O)O acres is to be reclaimed by this su D. Sidiary power project.
 The estimated cost of the dam and power plants will be $3,2OO,0OO Up ward of 100000 acres of land in the vicinity of Phoenix will be reclaimed. Most of this land is now in private