Geological Survey Water-Supply Paper 1475-J Ground Water in the Wupatki and Sunset Crater National Monuments, Coconino County, Arizona

1. The main aquifer in the Wupatki-Sunset Crater area is the Coconino sandstone, and water can be obtained from this aquifer throughout the area. Ground water is obtained locally from perched water zones in the Moenkopi formation and Quaternary alluvium; perched water may be present locally in the volcanic rocks.

2. The new well at the Wupatki headquarters (drilled in 1958) yielded 50 gpm during a 24-hour test, and other wells penetrating the Coconino sandstone in the area have yields of as much as 15 gpm. South of Flagstaff, beyond the Wupatki-Sunset Crater area, yields from the Coconino sandstone are as high as 450 gpm. The water-bearing characteristics of the Coconino sandstone in the area appear to be similar to those where the formation is more productive. It is possible that larger yields can be obtained from wells penetrating a greater thickness of the saturated aquifer and equipped with larger pumps.

3. The yields of wells tapping the alluvium and of springs issuing from the Moenkopi formation are small.

4. The chemical quality of water from wells is considered poor to satisfactory for domestic use, according to the U.S. Public Health Service standards for drinking water. Fluoride is present in the waters from Wupatki and Heiser Springs in amounts sufficient to make them undesirable as drinking water for children.

5. In the Sunset Crater National Monument area, a test well at site (A-23-8)16dca (pl. 20) would explore the possibilities of both shallow (perched) water below the volcanic rocks and deep ground water supplies from the Coconino sandstone. Such a well possibly would have to be 2,500 feet deep, because the depth to the regional water table may be as much as 2,000 feet. An alternate site for the drilling of a test well is shown at site (A-23-8)33ddd. The depth to the regional water table probably is somewhat less at this location, but there is less chance of obtaining a shallow supply.

6. At Wupatki Ruin, small supplies of perched water from shallow depths may be developed along the base of the escarpment of Woodhouse Mesa between Heiser and Wupatki Springs.

7. In the Citadel Ruin area in the Wupatki National Monument, a well drilled to a depth of about 1,600 feet would be the most likely source of ground water.

8. The possibilities of shallow perched water in the alluvium in the vicinity of Citadel Ruin could be explored by means of test holes drilled in the basin between Citadel Ruin and Arrowhead Sink. The average thickness of the alluvium is about 50 feet and it is not likely to exceed 100 feet.

9. Information needed to properly appraise the ground-water resources of an area can be obtained only when test holes and wells are drilled. This information includes drill cuttings taken at intervals of 10 feet or less; measurements of water levels, especially during periods of no drilling; and samples of water for chemical analysis from each water-bearing zone penetrated.