Major aquifers, well yields, number of index wells and date of last water-level sweep are shown in Table 6.2-3. Figure 6.2-6 shows water-level change between 1990-1991 and 2003-2004. Figure 6.2-7 contains hydrographs for selected wells shown on Figure 6.2-6. Figure 6.2-8 shows well yield for one well. 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 in the basin include recent stream alluvium, basin-fill and sedimentary rock (Cottonwood Wash and Muddy Creek formations).
Most of the basin geology consists of consolidated crystalline and sedimentary rock.
Data on natural recharge, groundwater in storage and groundwater flow direction is not available for this basin.
- Refer to Figure 6.2-6. Water levels are shown for wells measured in 2003-2004.
- The Department annually measures two index wells in this basin. Hydrographs for these two wells are shown on Figure 6.2-7.
More recent hydrographs of the index wells may be available through the Department's GWSI webpage.
- The water level in one well was at a depth of 21 feet and rose by more than 30 feet between 1990-1991 and 2003-2004. Water level in the other well is at a depth of 508 feet and was generally stable between 1990-1991 and 2003-2004.
Click to view Table 6.2-3 Groundwater Data for the
Grand Wash Basin
Click to view Figure 6.2-6 Grand Wash Basin
Click to view Figure 6.2-7 Grand Wash Basin Hydrographs
Showing Depth to Water in Selected Wells
Click to view Figure 6.2-8 Grand Wash Basin