The Upper Hassayampa Basin was defined by Anderson, Freethey and Tucci (1992) as a “West Basin”. These basins are generally arid and groundwater inflow and outflow are relatively small with little or no stream baseflow.
Upper Hassayampa Basin
The main aquifer in the Upper Hassayampa Basin is basin-fill deposits found along valleys between the mountains. These deposits consist of gravel, sand, silt and clay. In the mountainous, eastern part of the basin, fractured crystalline and consolidated sedimentary rocks yield small amounts of water to wells. Near Wagoner, stream deposits overlying crystalline rock are up to 135 feet thick. North of the Vulture Mountains, in the southwestern part of the basin, the basin fill varies from a few tens of feet thick to over 1,000 feet thick near the middle of the valley.
Groundwater flow is generally from north to south. Groundwater recharge is estimated at 8,000 AFA and groundwater in storage is estimated to range from 1.0 to 1.1 maf. Water levels in wells measured in 2003-‘04 varied from 20 feet bls near Wickenburg to 817 feet bls near Congress. Water level change data from wells measured in 1990-‘91 and 2003-‘04 show relatively stable groundwater levels (Figures 5.4-6 and 5.4-7). The median well yield in the basin was 125 gpm reported on registration forms for 61 large (>10-inch) diameter wells (Table 5.4-6). Groundwater quality is generally good although drinking water standards for arsenic and other metals have been equaled or exceeded in wells near Wickenburg.
Click to view Table 5.4-6 Groundwater Data in the Upper Hassayampa Basin
Click to view Figure 5.4-6 Upper Hassayampa Basin Groundwater Conditions
Click to view Figure 5.4-7 Upper Hassayampa Basin Hydrographs Showing Depth to Water in Selected Wells