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 3.5-5. Figure 3.5-6 shows aquifer flow direction and water-level change between 1990-1991 and 2003-2004. Figure 3.5-7 contains hydrographs for selected wells shown on Figure 3.5-6.  Figure 3.5-8 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 Douglas Basin Hydrology.

Major Aquifers

• Refer to Table 3.5-5 and Figure 3.5-6.
• The major aquifers in the basin are basin fill and basin fill with interbedded volcanic rock in the Douglas area.
• As seen on Figure 3.5-6, in the vicinity of Elfrida, groundwater flow directions have been altered due to agricultural pumpage.
• Flow direction is generally from north to south and east to west south of Elfrida

Well Yields

• Refer to Table 3.5-5 and Figure 3.5-8.
• As shown on Figure 3.5-8 well yields in this basin range from less than 100 gallons per minute (gpm) to more than 2,000 gpm.
• One source of well yield information, based on 656 reported wells, indicates that the median well yield in this basin is 600 gpm.
• In general, the highest well yields are north of Elfrida and west of Pirtleville.  All well yields in the vicinity of Bisbee are less than 100 gpm.

Natural Recharge

• Refer to Table 3.5-5.
• The principal source of recharge for this basin is mountain-front precipitation.

• Natural recharge estimates range from 15,500 acre-feet per year (AFA) to 22,000 AFA.

Water in Storage

• Refer to Table 3.5-5.
• Storage estimates for this basin range from 26 million acre-feet (maf) to 32 maf to a depth of 1,200 feet. 

Water Level

• Refer to Figure 3.5-6. Water levels are shown for wells measured in 2003-2004.
• The Department annually measures 27 index wells in this basin. Hydrographs for six of these wells are shown in Figure 3.5-7.  More recent hydrographs of the index wells may be available through the Department's GWSI webpage.
• The Department measures water levels four times daily at one automated groundwater monitoring site in the basin. 
• The deepest recorded water level in 2003-2004 is 337 feet north of Elfrida and the shallowest is 65 feet northwest of Pirtleville.