438 TiiiRTv-FiR?T Annual Rf.port 



Department of Agricultural Chemistry. Although this arrange- 

 ment was never jnit into effect, due to a change in plans for the 

 reclamation of water-logged areas in the \'alley, the rules were 

 formulated after very careful consideration of the problem from 

 everv known angle and may possibly have some future value. 

 B'or that reason they are given here. 



RULES FOR Till- BLKXUING OF PUMPED WATER WITH CANAL WATKR UNDEi^ 

 THE SALT RIVER VALLEY PROJECT 

 I. The blended water delivered to irrigators may contain not more than 50 

 parts per 100,000 of chloride, estimated as sodium chloride, or not more 

 than 100 parts per 100,000 of total dissolved salts, unless in the opinion 

 of the University of Arizona Department of Agricultural Chemistry an 

 unusually large part of the dissolved salts is temporary liardness or bicar- 

 bonate of lime. 

 II. Black alkaline waters may not be blended m proportions that will give 

 the blended water a permanent black alkali content by the method of 

 analvsis used in the above named department. 

 III. Pumped water that shows by analysis at the time a lower content of 

 chlorides and total dissolved salts than the unblended water of the canal 

 into which it is pumped may be used in any quantity, provided the result- 

 ing water meets the standard of Rule II. 



In formulating these rules the department rejects the erroneous popular 

 opinion that pumped water is inferior to gravity water of similar composition. 

 The limits set are much lower than those accepted by some other competent 

 authorities. Waters containing more than double the amount of chlorides and 

 solids permitted bv the above rules have been used successfully for centuries 

 in other arid countries. The department, however, has kept in mind the possi- 

 bility of future damage to valuable lands rather than the immediate profitable 

 use of waters of doubtful character. The waters permitted by the above rules 

 are of better quality than the usable portion of the natural flow of Salt River 

 before the floodwaters were impounded. The rules also insure water of con- 

 siderably better quality than the flow of the Gila River at Kelvin from 

 September, 1917, to July, 1918, with the exception of a few short periods of 

 flood. This is representative of water that has been used successfully for a 

 very long period at Florence. Black alkaline waters have been excluded on 

 the' ground that the natural flow of Salt River was rarely, if ever, black 

 alkaline and that black alkali, even in otherwise tolerable amounts, has a moi*e 

 or less deleterious physical effect on the soil. 



CHARACTER OF THE GROUNDWATERS IMMEDIATELY 

 EAST OF THE AGUA FRIA RIVER 

 In April the department was asked to report on the qualit}' 

 of the groundwaters available by pumping immediately east of 

 the Agua Fria. Certain portions of the report prepared at the 

 time are of public interest, and conse([uently are made a part of 



this report. 



With continued operation of the Salt River Project, unaccompanied by 

 drainage, the groundwaters in the neighborhood of the Agua Fria and to the 

 eastward have risen till in places they now stand quite near the surface. This 

 lias resulted in rise of alkali, which becomes very strong in some localities and 

 would lead one to suspect strongly alkaline groundwaters. Analyses of water? 

 taken in this district several years ago showed the presence of considerable 

 alkali at that time. There has also existed a large body of rather alkaline water 

 to the cast and northeast of this district extending beneath and lieyond the 

 city of Phoenix. Surface wells along the Salt River Valley Canal in Range 2 



