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 3.14-6.  Figure 3.14-6 shows aquifer flow direction and water-level change between 1990-1991 and 2003-2004.  Figure 3.14-7 contains hydrographs for selected wells shown on Figure 3.14-6.  Figure 3.14-8 shows well yields in five yield categories.  A description of aquifer data sources and methods as well as 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 Willcox Basin Hydrology.

Major Aquifers

• Refer to Table 3.14-6 and Figure 3.14-6.
• The major aquifers in the basin are recent stream alluvium from stream and lake-bed deposits and basin fill.
• The Willcox Basin is a “closed basin” with no inter-basin groundwater inflow or outflow.
• Groundwater flow conditions have been altered significantly in several locations due to groundwater pumping as shown by flow directions on Figure 3.14-6.  Historically flows were from the perimeter of the Sulphur Springs Valley toward the Willcox Playa.

Well Yields

• Refer to Table 3.14-6 and Figure 3.14-8.
• As shown on Figure 3.14-8 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 1,007 reported wells, indicates that the median well yield in this basin is 750 gpm.

Natural Recharge

• Refer to Table 3.14-6.

• Natural recharge estimates range from 15,000 acre-feet per year (AFA) to 47,000 AFA.

Water in Storage

• Refer to Table 3.14-6.

• Storage estimates for this basin range from 42 million acre-feet (maf) to 59 maf to a depth of 1,200 feet. 

   

Water Level

• Refer to Figure 3.14-6.  Water levels are shown for wells measured in 2003-2004.
• The Department annually measures 47 index wells in this basin.  Hydrographs for 12 index wells and four other wells are shown in Figure 3.14-7.  Index well hydrographs are: A-E, G-K, M and N.  More recent hydrographs of the index wells may be available through the Department's GWSI webpage.
• The deepest recorded water level in 2003-2004 was 431 feet in the vicinity of Highway 191 near the southern basin boundary and the shallowest recorded water level in 2003-2004 was 36 feet in the vicinity of Willcox. 

Click to view Table 3.14-6 Groundwater Data for the

Willcox Basin

Click to view Figure 3.14-6 Willcox Basin

Groundwater Conditions

Click to view Figure 3.14-7 Willcox Basin Hydrographs

Showing Depth to Water in Selected Wells

Click to view Figure 3.14-8 Willcox Basin Well Yields

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