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Abstract The Rampart Cave Member of the Muav Limestone is the major aquifer in the western Grand Canyon district based on spring locations in the walls of the Grand Canyon. Permeabilities of the Paleozoic rocks are locally enhanced by faulting. Caves are not associated with springs in the area.
Most of the waters discharging from the carbonate rocks in the district are of the calcium-magnesium-bicarbonate type; total dissolved solids range between 272 and 810 mg/l, temperatures range between 69 and 80 F, and discharges range up to about 7 ft/sec. Minimum recharge rates in the district are on the order of 0.1 in/yr. Total spring and seep discharge in the area is approximately 20 ft/sec.
Prospects for developing large ground water supplies in the district are dim because: (1) the total recharge is small, (2) permeabilities are small, and (3) there are no extensive permeable zones under the plateaus in which large quantities of water are in storage. Selected fault zones that supply water to large springs offer the most promising areas for drilling. The drill sites should be located on the downthrown block along the fault and the hole should penetrate to the bottom of the Rampart Cave Member. Minimum drilling depths along promising faults in the area are 1,900 ft. Prospects for ground water development from the Paleozoic rocks on the Shivwits plateau are virtually non-existent because the rocks in the region appear to be essentially dry, even along permeable fault zones.
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