Major aquifers, well yields, estimated natural recharge, number of index wells and date of last water-level sweep are shown in Table 8.5-6. Figure 8.5-6 shows aquifer flow direction and water-level change between 1994-1995 and 2004-2005 for the entire Tucson AMA. Figures 8.5-6A-B show depth to water during 2004-2005 and water-level change between 1994-1995 and 2004-2005 for selected wells by sub-basin. Figure 8.5-7 contains hydrographs for selected wells shown on Figures 8.5-6A-B. Figure 8.5-8 shows well yields in five yield categories. Underground Storage Facilities (USF) and Groundwater Savings Facilities (GSF) are shown on Table 8.5-7 with facility name, facility permit number and type, permittee name, permitted acre-feet per year and water source. Locations of USFs and GSFs are shown on Figure 8.5-9. 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.
- Refer to Table 8.5-6 and Figure 8.5-6
- The major aquifers are recent stream alluvium and basin fill including the Fort Lowell Formation and the Tinaja Beds.
- In the Upper Santa Cruz sub-basin groundwater flows from the mountains along the eastern AMA boundary toward the center of the AMA then north-northwest. In the Avra Valley Sub-basin groundwater flows from south to north.
- Refer to Table 8.5-6 and Figure 8.5-8
- As shown on Figure 8.5-8, well yields are generally between 100 and 1,000 gallons per minute (gpm).
- One source of well yield information, based on 1,063 wells, indicates that the median well yield is 520 gpm.
- Refer to Table 8.5-6
- Natural recharge in the Tucson AMA is approximately 60,800 acre-feet per year.
- Principal sources of natural recharge are groundwater inflow from the south, infiltration of runoff into stream channels, and mountain front recharge.
- Refer to Figure 8.5-6A-B. Water levels are shown for wells measured in 2004-2005.
- The Department annually measures 137 index wells in this AMA. Hydrographs for nine of these wells are shown on Figure 8.5-7.
- The deepest water level shown is 633 feet in the vicinity of Three Points in the Avra Valley sub-basin (Figure 8.5-6A), and the shallowest is four feet in the eastern portion of the Upper Santa Cruz sub-basin (Figure 8.5-7B).
- Refer to Table 8.5-7 and Figure 8.5-9.
- There are 10 active USFs and six active GSFs.
- Total permitted storage capacity for USFs is 293,000 acre-feet per year and total permitted storage capacity for GSFs is 82,986.
Table 8.5-6 Groundwater Data for the Tucson AMA
Figure 8.5-6 Tucson AMA Groundwater Conditions
Figure 8.5-6A Avra Valley Sub-basin Groundwater Conditions