Arizona republican., 1921-08-12

interest to every business man in the Salt River valley to keep in close touch with it's development and to render any assistance which can possibly be given.
 Farmers of the Salt River valley should be interested in the develop ment of this section, for it is a proved fact that the price of land has always advanced with the devel opmept of new land. Market condi- tions are improved with the volume of products marketed. The deyel- opmept of the Florence Casa Grande valley will add a tremendous amount of ta axable wealth to the state with out in any way adding to its bur dens. There is every reason for helping the people of the San Carlos district to realize theid dreams and their is no reason why we should not help them.
 "The Phoenix chamber of com merce has always been in the front rank of boosters. for the San Carlos dam. A delegation from that body attended the former meetings of the association and will be on hand to- day. The Phoenix chamber of com merce stands squarely behind the San Carlos project. :"
 The called San Carlos project has for its object the impounding of the waters of the Gila river so as to furnish irrigation for the great Flor ence- Casa Grande valley. lying in the south central part of Arizona be- tween Phoenix and Tucson. and con- taining not less than 500.000 acres of extremely fertile 1and.s
 Ideal Site For Dam
 Through the valley flows the Gila river, the waters of which it is pro- posed to store behind the so- called San Carlos dam. This dam is to be constructed in the box canyon of the Gila river about five or six miles be- 1 low San Carlos. Such a dam, built
 according to the best ideas that have l been brought out by consideration oi l the project and it's potentialities, will l impound water sufficient to make a l lake many square miles in area and containing a volume of water suffi- l cient to cover 1885, ,326 acres of land l 12 inches deep.
 This amount of water would be enough to provide irrigation
 throughout the year to more thar l 150,00a acres-acres which now ars | little more than primal desert in tht heart of Pinal county
 I The cost of building the required dam and impounding the quantity l of water outlined in the foregoins | will be approxima tely $S,000,0 900. Int dam, under the plans which have been prepared by those interested 1T I the project. will have life of at 1eas I 225 years. according to the United l States board of army engineers. Thi.
 estimate of the life of the dam 1.
 based on the assumption hat .nothins
 at all will be done in the interval t' T remove the silt deposits, while unde modern methods of keeping the dan
 free of excessive deposits it's life ma.
 be prolonged indefinitely.
 Another factor which must b.
 taken into consideration in examin
 ing the San Carlos dam project i that irrigation experience in the Sal River valley, lying adjacent to tn
 Florence-Casa Grande valley an
 supplied with water from the Roose
 welt dam, has shown that the irriga
 ton of 150,000 acres of land unde the San Carlos project will so rais
 the water level under adjoining land within few years that pumping O these lands, which would not b reached by the waters from the dan will be easily feasible upon an addi
 tional 100000 acres. In other words
 the construction of tte San Carlo , dam will increa SC. in few years. tn , | productive area of central Arizon , by 250.0f0 acres, which is considere a conservative estimate.
 , Statistics Show Value of Dam To come now to consideration C !, the value in dollars and cents of tn
 proposed dam it is only necessary point out the fact that the fertilizin
 value of Gila river silt in solutio 5 enriches the land at an estimate 7 7 rate of s4 S7 an acre each year. F'o ! 150,000 acres this increase comes 2 s717.000 a year-a tidy sum for an portion of the earth's surface.
 That these estimates are not tn E dreams of heated imagination o the vagaries of an excitable hope shown by the fact that a carefu ' checking of the volume of wate ! passing the San Carlos damsite fror October 1, 1914 to October 1. 1917. re
 vealed that more than 100000 acr z feet of water were running ava ' each year. Looking at this run-oi . from the standpoint of conservation = a 220-foot dam at San Carlos wi ~ water all the acreage contained i, the project for a period of neary fou " years if not a drop of water flow i, into the reservoir during that time "a a contingency too remote even fc r serious thought.
 70 With reference to the conditions .r the dam itself in connection with II s construction of such structure 2
 has been proposed, it is pointed ol " that the canyon walls and bed roc " at San Carlos are composed of har r. quartzsite, rock of the finest qua l. ity and of the strength required If support a great masonry dam. TT
 depth from surface to bed rock ;