1902, to August 1, 1904. With a capacity of 854,800 acre-feet, under the same conditions, it would have been dry from May 1, 1903, to August 1, 1904.

During the succeeding cycle, the effect of the San Pedro would have been nil, owing to the discharge of surplus water over the spillway. The above calculations have been based on the amount of water actually available. Similar calculations, using the amount physically available, show that the only effect of using the water now diverted for irrigation in the Solomonville Valley is to diminish the time the reservoir is empty during the extremely dry cycle. The mass diagram, just referred to, also shows the behavior of the reservoir, including the effect of the San Pedro River, and water now diverted in the Solomonville Valley.

The mass diagram showing the effect of diversions at Solomonville is based on an annual net loss of 58,000 acre-feet. This figure is explained later in Appendix B of this report. This diagram indicates that the 714,450 capacity reservoir with an annual draft of 300,000 acre-feet and with combined flow from Solomonville and the San Pedro would have been empty from March 1, 1904, to August 1, 1904. With a capacity of 854,800 acre-feet it would have contained 2,000 acre-feet on August 1, 1904, when the succeeding flood began. During the balance of the 21-year period the addition of the Solomonville diversion water or the San Pedro would have no appreciable effect, since the run-off without this supply was more than sufficient to meet the demands of the project.

HISTORY OF IRRIGATION ON GILA RIVER.

Irrigation, an essential requirement of agricultural development in the Southwest, has been practiced along the Gila since prehistoric times. Remains of ditches and other unmistakable evidences of irrigation by an ancient race, which apparently reached a higher stage of civilization than the Indians known to the early settlers, are to be found at different places in the valleys of the Gila and its tributaries.

The Pima Indians, who may be descendants of these prehistoric irrigators, were irrigating a large area of land along the Gila when the first exploring Jesuits penetrated this territory during the middle of the sixteenth century.

While the Jesuits and their followers intermittently irrigated a limited area of land along the Santa Cruz, and possibly along the San Pedro (both tributaries of the Gila), yet no important irrigation other than that practiced by the Indians took place until some time after the American military occupation in the middle of the nineteenth century, when protection to the settlers and markets for the crops were afforded.

A small area of land was irrigated at this time, in connection with the overland stage stations. This stage line was established in 1857, and the route, after leaving Tucson, was through the Pima villages on the present Gila River Indian Reservation, cutting across the big bend of the Gila and touching the river again at the present Gila Bend station; thence continuing along the river to its confluence with the Colorado at Yuma. All of the land formerly cultivated in connection with these old stage towns, as well as the other older irri

gated area on the lower Gila, has since been allowed to revert to the desert state.

Subsequent diversion of the waters of the Gila by the whites proceeded in a rather uniform manner up the stream. Irrigation in the Florence district started earlier than in the Solomonville Valley, while the first irrigation in the Duncan Valley took place at a later date than in the other districts lower down on the Gila.

The first irrigation in the Florence district was initiated by, and for the profit of, the early Indian agents of the reservation, just below and contiguous to the Florence district.

The pioneers of the next valley up the river, the Solomonville district, were Mexicans, who ventured into this uncivilized territory in the early seventies. Americans followed, and with the advent of the Mormon colonists a few years later rapid agricultural development took place.

In the Duncan district, as well as along the upper tributaries, the Mexicans made the earliest diversions. Irrigation here, however, had many disadvantages, adverse natural conditions together with remoteness from civilized centers or military protection considerably delaying later diversions of the waters of the Gila for irrigation.

The progress of irrigation along the Gila River since the American occupation has varied in the different districts. Coincident with the development and consequent diversions of the river waters in the valleys on the upper reaches of the stream, the water supply for the irrigated districts lower down soon began to suffer, and in the extreme lower valleys many acres of irrigated land were no longer cultivated. In the middle Gila districts the agricultural development was either stopped entirely or greatly retarded.

The present status of irrigation along the Gila is summarized in the following tabulations.

The areas shown were actually under irrigation by the use of ditches and pumps, taking water direct from the Gila River at the time (1914) of the survey made in connection with this investigation.

Principal districts.

No. 1. Duncan Valley

No. 2. Solomonville-Safford Valley.

No. 3. San Carlos Indian Reservation__

No. 3. Florence-Casa Grande Valley

No. 4. Gila River Indian Reservation_

No. 5. Lower Gila district (west of Pima Indian Reservation)

Winkelman section

Between districts Nos. 1 and 2.

Between districts Nos. 2 and 3.

55, 821. 4
24, 045. 0
335.0
90.0

27.0

3, 621.0

11, 089. 0

94, 693. 4

In addition to the foregoing areas under cultivation at the time of the survey the following acreages are found to have been previously irrigated:

No attempt was made to obtain complete data covering the previously irrigated areas on the lower Gila or on the tributaries.

It should be pointed out that these previously irrigated areas do not necessarily represent areas that have been cultivated contemporaneously with the lands under cultivation at the present time, since in many instances the present cultivated areas were not reclaimed until after the abandonment of the lands now classified as previously cultivated.

In the four principal irrigation districts along the Gila or the districts numbered 1, 2, 3, and 4 in this report there is a white population of 10,670. The total Indian population directly affected by diversions of the Gila River waters on the two reservations included in the above districts, according to the most recent census, is 4,580.

Leaving aside the Indian reservation lands and considering only the four districts mentioned above there are 1,584 different persons or interests who are the present owners of land which is now being irrigated or which has been previously irrigated by ditches diverting water from the Gila River.

In the territory covered by districts Nos. 5 and 6, or the lower Gila, the tributaries, and the extreme upper Gila, it is estimated that 3,000 persons are dependent upon the agricultural industry. The total population along the Gila River and its tributaries, not including the Salt River, supported directly or indirectly by the agricultural industry, amounts to approximately 18,000, or a little more than one-twelfth of the total population of the State of Arizona.

A brief description and history of irrigation in each of the irrigated districts along the Gila and its tributaries follows, the districts being reported upon in the numerical order shown in the table of areas under cultivation at the time of the survey.

IRRIGATION IN DUNCAN VALLEY, DISTRICT NO. 1.

The Duncan district embraces a narrow valley about 30 miles in length, the upper 7 miles of which lies in Grant County, N. Mex., while the remaining portion is in Greenlee County, Ariz., which was created from a part of Graham County in 1911.

The elevation of the river bed at the extreme upper end of the Duncan Valley is 3,800 feet, while at the extreme lower end it is 3,400 feet. The elevation of the Government bench mark at Duncan, near the center of the valley, is 3,643 feet.

The Arizona & New Mexico Railroad from Lordsburg to the mining towns of Clifton and Morenci traverses nearly the entire length of the valley.

Alfalfa, grain, and vegetables constitute the principal crops, and stock raising is also an important industry in this valley. The mountainous territory contiguous to the Duncan Valley has provided a large area of excellent cattle range. This range, which in past years has been overstocked, is still capable of feeding a large number of cattle. Part of the hay raised in the valley is fed to cattle during the winter, while the remaining portion is usually baled, and, like the vegetables and other produce, finds a ready market in the near-by mining towns of Clifton and Morenci.

The total population of the Duncan Valley amounts to 1,400 persons, depending directly or indirectly on the agricultural industry. Of this number 750 reside in the village of Duncan, after which the valley is named and which forms practically the only town in the district.

The farming class of the Duncan Valley consists of Americans and a few Mexicans. Many of the former landowners have sold out and left the country. In 1895 a colony of Mormons settled in the upper part of the valley near what is called Franklin Flat, and to them credit is due for agricultural development in that section.

Most of the farms are situated in the upper portion of the valley, extending from the vicinity of the town of Duncan to the Apache Box Canyon, which terminates the upper end of the valley. In that portion below Duncan the irrigated area is not continuous, and many small areas are irrigated by means of pumps.

Irrigation began relatively later in the Duncan Valley than in the other agricultural districts lower down on the Gila. The cultivated areas in this valley comprise a rather narrow strip of land along each bank of the river. This unfavorable_natural condition, together with the hostile activities of the Apache Indians during the early history of this region, no doubt were factors largely responsible for the retardation of its development.

The historical analysis of irrigation in this valley, compiled from the data collected in this investigation, shows that the first irrigation in the Duncan district was on land now being served by the Sunset Canal and was carried on by means of a very small ditch constructed in 1876. The next oldest ditch is the Cosper, Martin & Wilson, and this ditch represents a consolidation of two ditches, the Cosper-Martin and the Wilson, the latter being the much older of the two, having been constructed in 1879. The irrigated area under these two ditches was limited, as it is estimated that in 1880 only 250 acres were being served by these two ditches.

From 1880 to 1890 a number of small canals and a few larger ones were constructed, in addition to the two older ditches, and in the latter year the estimated irrigated area was 1,469 acres. In 1900 the cultivated area had increased to 3,660 acres, and at the time (1914) when surveys were made in this valley in connection with the present investigation, 13 canals and 9 pumping plants served to irrigate 6,268.5 acres. The nine pumping plants, lifting water direct from the Gila River, supply water to irrigate a combined area of 146 acres, which is included in the foregoing area.

Of the present cultivated area 2,037.2 acres are situated within the State of New Mexico, and six of the principal canals of the Duncan Valley have their headings east of the New Mexico line, five of these canals irrigating land in that State.

Besides the 6,268.5 acres of irrigated area in this valley, there was found an additional area of 125.5 acres which gave evidence of having been previously irrigated.

Between Guthrie Canyon, which marks the lower end of the Duncan Valley, and the first diversion made for the Solomonville Valley, there are three small pumping plants irrigating a combined area of about 90 acres, near the mouth of the San Francisco River.

A majority of the ditches in this district are owned by mutual companies or corporations, and the stockholders, as a rule, are the owners of the land under the canal. The few ditches and pumping plants not under corporate ownership are held by individuals or on a partnership basis.

Of the 13 canals serving to irrigate land in the Duncan Valley, 10 have been incorporated, and 167 landowners under the different canals are holders of the outstanding stock. The other 3 canals, together with the 9 pumping plants, are owned by 15 persons, thus making a total of 182 persons directly interested in irrigation in the Duncan Valley. All but two of the above number are landowners under the canals. The water is not made appurtenant to the land, and the owner may use the water called for by his shares of stock as he may see fit. The water right represented by each share of stock, as a rule, is the pro rata of all the water available for distribution.

The Duncan district has been singularly free from litigation over water rights. A suit which promised the settlement of the relative rights to the use of the Gila waters, between the farmers of the Duncan Valley, and those of the Solomonville Valley, was started in 1912. This suit, which was known as the William A. Gillespie, of the Solomonville Valley, v. The Valley Canal Co. et al., of the Duncan Valley, was in the form of an injunction proceeding, and was filed in the superior court of Graham County in the spring of 1912. Answer was made by the attorneys for the defendants, and it appears the case was then allowed to drop, as it has not been called to trial.

With one or two exceptions the lands under the different ditches have been continuously arrigated since their initial irrigation. This irrigation has not been carried on continuously under the same ditch, but a great deal of land, especially the irrigated areas in New Mexico, has been served at various times by a number of small ditches. The ditches now in use, though higher and more permanent, are virtually the same as the canals formerly used, which were located closer to the river. The pumping plants which have been installed recently in this district, serve to irrigate some of the small tracts formerly covered by gravity ditches.

Herewith is given a tabulation summarizing both the results of the survey made in connection with this investigation, and also an historical analysis of the development of irrigation in this district.

The results of the survey have been shown in this tabulation, as well as in the tabulations for the other districts, under three-column headings, as follows: "Pres. cult.," or present cultivation; "P. C." or previous cultivation; and "N. C. (fenced)," or areas that have never been cultivated but which are fenced.

Under "Pres. Cult." are the areas which were found to be under actual cultivation at the time of this survey, in 1914, and which