Major aquifers, well yields, estimated water in storage, number of index wells and date of last water-level sweep are shown in Table 7.3-5.  Figure 7.3-5 shows aquifer flow direction and water-level change between 1990-1991 and 2003-2004.  Figure 7.3-6 contains hydrographs for selected wells shown on Figure 7.3-5.  Figure 7.3-7 shows well yields in six 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. 

Major Aquifers

• Refer to Table 7.3-5 and Figure 7.3-5.
• The major aquifer in this basin is basin fill.
• Flow direction is from the basin edges to a cone of depression in the central portion of the basin. 
• As shown on Figure 7.3-5, the water level in the area of the cone of depression has risen by at least one foot and as much as 30 + feet between 1990-1991 and 2003-2004 due to use of Central Arizona Project (CAP) water in place of groundwater and CAP recharge at the Vidler Water Recharge Facility west of Centennial.

Well Yields

• Refer to Table 7.3-5 and Figure 7.3-7
• As shown on Figure 7.3-7, well yields are generally between 1,000 gallons per minute (gpm) to greater than 2,000 gpm. 
• One source of well yield information, based on 157 reported wells, indicates that the median well yield is 1,620 gpm.

Natural Recharge

• Refer to Table 7.3-5
• Natural recharge estimates range from less than 1,000 acre-feet per year (AFA) to less than 1,200 AFA.
• The largest source of natural recharge is runoff infiltration through the Centennial Wash alluvium (ADWR 1994b).

Water in Storage

• Refer to Table 7.3-5
• Storage estimates for this basin range from 13 million acre-feet (maf) to 27 maf to a depth of 1,200 feet. 

Water Level

• Refer to Figure 7.3-5. Water levels are shown for wells measured in 2003-2004.
• The Department annually measures 34 index wells in this basin.  Hydrographs for 11 index wells are shown on Figure 7.3-6. 
• The deepest water level shown on the map is 561 feet in the southwestern portion of the basin and the shallowest is 25 feet in T1N R8W.

Table 7.3-5 Groundwater Data for the Harquahala Basin

Figure 7.3-5 Harquahala Basin Groundwater Conditions

Figure 7.3-6 Harquahala Basin Hydrographs Showing Depth to Water in Selected Wells

Figure 7.3-7 Harquahala Basin Well Yields

Arizona Water Atlas Home

Lower Colorado River Planning Area Home

References and Supplemental Reading for the Harquahala Basin