202 IRRIGATION IN THE SOUTHWEST. 



of that iferntory. The valley contains a boundless extent of equally 

 valuable desert land, whose only hope of development lies In the 

 coustruction of reservoirs. The one chiefly relied upon is known as 

 the Tonto Basin, at the junction of Tonto Creek and Salt River, some 

 80 or 90 miles above the city of Phoenix, the capital of Arizona. A 

 dam is here projected which will impound over 1,000,000 acre-feet, or 

 sufficient water to cover one million acres one foot deep. The tribu- 

 tary watershed area is over 5,800 square miles, from 2,500 to 8,000 feet 

 in altitude, affording an annual run-oft sufficient to supply the reser- 

 voir. The dam will be constructed of masonry, and will be 250 feet in 

 height, whose length between the solid sandstone walls of the canyon 

 will be 150 feet at base and 650 feet at top. The dam is estimated to 

 cost $1,500,000, and three years' time will be needed to build it. The 

 work has been undertaken by a corporation styled the Hudson Reser- 

 voir and Canal Company of New York. The enterprise is one of the 

 most extensive and important ever projected in the arid region, and 

 one of the very few which has a prospect of being profitable to the 

 stockholders, by reason of the fact that the water can be immediately 

 sold at wholesale to a population waiting, with canals already built, 

 for its utilization. The canal system of Salt River valley commands 

 a greater area of unimproved desert land than the water of the unres- 

 ervoired stream will serve. 



RESERVOIRS ON THE GILA RIVER. 



The Gila river, above its junction with the Salt, is quite as com- 

 pletely utilized as the latter stream, although the development of irri- 

 gation by canals has taken place upon the upper valleys at a much 

 greater rate than in the main valley of the stream. This has resulted 

 In depriving the lower appropriators of their usual supply in the dryer 

 portions of the year, and caused great loss and privation, particularly 

 among the Pima and Maricopa Indians on the Sacaton reservation. As 

 these peaceful and industrious tribes are the wards of the government, 

 an effort is being made to restore their water supply and furnish 

 their parched fields with the needed element, by impounding the flood 

 waters of the Gila in a mammoth reservoir. To this end the United 

 States Geological Survey has been charged with the task of investi- 

 gating the various available sites to determine where a dam can be 

 most advantageously constructed. Borings have been made at theButtes, 

 some fifteen miles above Florence, at Riverside, fifteen miles higher up 

 and at the western end of the San Carlos reservation, where the Gila 



