Major aquifers, well yields, estimated natural recharge, estimated water in storage, number of index wells and date of last water-level sweep are shown in Table 3.10-6.  Figure 3.10-6 shows aquifer flow direction and water-level change between 1990-1991 and 2003-2004.  Figure 3.10-7 contains hydrographs for selected wells shown on Figure 3.10-6.  Figure 3.10-9 shows well yields in five yield categories.  Descriptions of aquifer and well data sources and methods, including water-level changes and well yields, are found in Volume 1, Appendix A.  For more information on groundwater in the basin see Safford Basin Hydrology.

Major Aquifers

• Refer to Table 3.10-6 and Figure 3.10-7.

• The basin is composed of three sub-basins.

• The southernmost sub-basin, the San Simon Valley sub-basin, consists of recent stream alluvium and contains artesian conditions in the lower aquifer. 

• The middle sub-basin, the Gila Valley sub-basin, contains older and younger basin fill.  The principal aquifer is the younger basin fill.

• The northern sub-basin, the San Carlos Valley sub-basin, consists of younger stream alluvium and basin fill. The principal water-bearing unit is the younger stream alluvium.

• Flow direction is generally from south to north, however, the flow is from north to south in the vicinity of San Carlos.  Flow directions have been altered due to pumping south of Interstate 10.

Well Yields

• Refer to Table 3.10-6 and Figure 3.10-9.

• As shown on Figure 3.10-9, well yields in this basin range from less than 100 gpm to more than 2,000 gpm.

• One source of well yield information, based on 1,494 reported wells, indicates that the median well yield in this basin is 600 gpm.

Natural Recharge

• Refer to Table 3.10-6.
• The only estimate for natural recharge in this basin is 105,000 acre-feet per year (AFA).

Water in Storage

• Refer to Table 3.10-6.

• Storage estimates for this basin range from more than 27 million acre-feet (maf) to 69 maf to a depth of 1,200 feet. 

Water Level

• Refer to Figure 3.10-7.  Water levels are shown for wells measured in 2003-2004.
• The Department annually measures 50 index wells in this basin.  Hydrographs for thirteen wells are shown in Figure 3.10-8.  More recent hydrographs of the index wells may be available through the Department's GWSI webpage.
• Water levels are as deep as 517 feet in the vicinity of Interstate 10 and as shallow as 21 feet in the Safford, Pima and Thatcher area.

Click to view Table 3.10-6 Groundwater Data for the Safford Basin

Click to view Figure 3.10-7 Safford Basin

Groundwater Conditions

Click to view Figure 3.10-8 Safford Basin

Hydrographs Showing Depth to Water in

Selected Wells

Click to view Figure 3.10-9 Safford Basin

Well Yields

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