Arizona Agricultural Expkrimkxt Statiox 477 



feet. This appears to be a high duty for the water, but it is made 

 so by including about 3000 acres of lands along the Gila and under 

 the Casa Grande Canal, which receive gravity water also. 



Water level measurements were made on four dates, in March, 

 in May. in August, and in October. In the pumping district near 

 the Tweedy ranch there was a complete recovery from the pre- 

 ceding summer's pumping, and then followed a depression half a 

 foot greater than the previous one. The pumping district has been 

 extended south to the Lloyd Prouty ranch and with it also the 

 area of depression has increased. Along the Gila for two miles 

 back, the groundwater during May reached as high a level as has 

 been yet ol)served and receded in October to the usual minimum-- 

 a fluctuation of about two feet. 



The high price of gas oil (17 and 18 cents per gallon) and the 

 difficulty of getting a good grade,, have resulted in many of tiic 

 semi-diesel and Brons type engines being purchased. These en- 

 gines burn lower grade fuel oils known as 24 plus and 27 plus. 

 The 27 phis is best adapted to the semi-diesel, but even this grade 

 of oil is difficult to obtain. The Brons type engine burns the 24 

 plus oil readily, but no lower grade ought to be used because of 

 the increase of solid matter contained. The greater cost of these 

 engines offsets the lower price of the fuel oil. 



Two plants using compressed air to raise the water have been 

 installed, and unusual claims made for them regarding efficiency. 

 At one of these plants the depth to water is 40 feet and at the other 

 95 feet. The efficiency of this method of lifting water has been 

 shown in the past as being very low. The Department plans to 

 make tests on these plants very soon. 



The total rainfall and run-off have been normal. During the 

 vear 1920, 14,000 acre-feet passed Sasco. Of this flow 370 acre-feet 

 reached the Southern Pacific tracks at Eloy, but none reached the 

 tracks west of this ])oint. At Lirim there was a local run-of¥ of 

 1400 acre-feet. With the exception of the month of .Vugust it is 

 known that there was no run-oft' at iMaricopa. There were two 

 winter floods from the Santa Rosa Wash. 



SAN SIMON VALLEY 

 The Fourth Legislature of the State of Arizona, in Chapter 

 153, Session Laws, 1919, provided for special investigations of 

 water supply and irrigation possibilities in the three great valleys 

 of Cochise County. The largest item of the appropriation was for 

 an experimental artesian well in the San Simon Valley, a smaller 

 item was for a diversion dam in the Sulphur Spring Valley, and 



