Arizona Agricultural Experiment Station 439 



East and the eastern part of Range 1 East show high percentage of dissolved 

 >alts and chlorides, averaging higher than we would recommend for irrigatmg 

 purposes, as irrigation is usually practiced in tliis country, but nevertheless usable 

 i.n well-drained lands if sufficient water were available for occasional leachings. 

 Certain wells in this area, notably those in Section 12, Range 1 East, Township 1 

 North, are so saltv that they should be excluded from the project if it becomes 

 necess'arv to drawany water from this area. It is possible, however, that deeper 

 wells may vield better water than the shallow surface wells, as may be indicated 

 by the project well in Section 12, Range 2 East, Township 1 North, which, 

 while not of verv good quality, is much better than the shallow wells to the 

 west. In all probability, the quality of the water pumped in this area will 

 vary greatly from time to time as various alkaline pockets are drained, some- 

 times showing improvement, at others becoming worse. 



The waters west of the Agua Fria, beneath Range 2 North, Township 1 

 West, arc excellent in character almost without exception, so far as can be 

 judged by the analyses available. They are purer than tiic waters impounded 

 in Roosevelt Lake.' These waters probably are the groundwaters of the Agua 

 Fria River itself. To the north of the proposed project in Range 1 East, and 

 Townships 3 and 4 North, arc found some of the best irrigating waters of the 

 State; in fact the waters of this area arc ideal. They, too, arc probably the 

 tiroundwaters of the Agua Fria. A sample of the open flow of the river m 

 Section 27, Range 2 North, Township 1 West, shows practically the =- i • 

 composition as the groundwaters to the west. The water coming to the surface 

 in the slough, and suspected to be seepage from the area to the east, is identical 

 in character with the open flow of tiic river. The groundwater of the Agua 

 Fria shows its influence on the waters to some distance east of the river. The 

 zone of blending between the groundwaters of the Phoenix area and those ot 

 the Agua Fria appears to be in this region. The rise of the groundwater in the 

 Phoenix area has probably forced this zone westward and at the same time 

 brought the purer Agua Fria waters closer to the surface. As would be ex- 

 pected, the two types of groundwater drive wedges into one another so that a 

 serrated or ragged contact results. These wedges may be expected to shift 

 considerablv as will also the zone of blending, but the groundwaters of_ the 

 Agua Fria will proba1)lv always modify in large degree the average composition 

 of the waters of the western sections of Township 2 North, Range 1 East, in 

 which it is proposed to install the major part of the pumps of the project. It 

 is possible, also, that the shallow wells between the Salt River Project wells 

 and the river mav represent a thin, overlying sheet of the more alkaline water 

 to the eastward rather than a wedge of this water forced into tlie Agua Fria 

 underflow. In that case, deeper wells in Sections 6. 8. 17. and 19 will probably be 

 of qualitv equal to the project wells in Sections 9. 17. and 20. In general, it must 

 he noted that water developed in the northern half of the proposed project is 

 of better quality than that developed in tlie southern half. The water taken from 

 the canal in Section 1. Range 2 Nortli, Township 1 West, resembles the water 

 at Granite Reef rather than that at Joint Head. It may have come from the 

 north through some of the cross-cut canals, or be due to recent floodwaters at 

 Joint Head. 



The influence of other developments in the Valley on the probable future 

 composition of the available water should also be considered. The lowering of 

 the water table in the Phoenix District is imperative and will gradually be 

 accomplislied by suitable means. This will check the westward movement of 

 the saltv uroundwater of that area and promote the eastward movement of the 

 Agua Fria groundwater. While the lift will be increased by such drainage, 

 ♦he qualitv of waters developed under the western half of Range 1 East, Town- 

 ship 2 North, will be improved. Heavy pumping in the Litchton area will 

 lower the Agua Fria groundwater and tend to shift the zone of blending 

 westward, thus neutralizing to some degree the benefits of drainage in _ the 

 Phoenix area. If. however, the Agua Fria groundwater beneath Township 2 

 North. Raiicc 1 East, originates from the flow of the river, this effect will be 

 felt less strongly. Periods of flood in the Agua Fria will force the zone of 

 blending eastward while long periods of drouth will probably be marked by 

 the westward movement of the alkaline waters of the Phoenix area. 



