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As the demand for water increases across the southwestern United States, the region's utilization of and dependence on water stored in groundwater aquifers has risen in kind. The Coconino Aquifer (C-aquifer) underlies much of the southwestern Colorado Plateau and is a primary source of groundwater in northeastern Arizona. One of the largest commercial users of water from the C-aquifer in Apache County, Arizona, is Springerville Generating Station, a coal-fired power plant owned and operated by Tucson Electric Power. The area surrounding the power plant, located between the cities of Springerville and St. Johns, Arizona (the Springerville-St. Johns area), is geologically complex: it contains the Cedar Mesa anticline, an underlying CO2 reservoir, extensive travertine deposits, and several faults, including the Coyote Wash fault. The Coyote Wash fault and Cedar Mesa anticline play a significant role in the relationships between the St. Johns CO2 gas field, groundwater flow, and the travertine deposits. Yet, the interaction between the structures and the effect they have on groundwater flow is poorly constrained. By mapping the subsurface geology utilizing borehole records and by creating a groundwater model of the area, this study determined that the Cedar Mesa anticline acts as a partial horizontal barrier to groundwater flow, whereas the Coyote Wash fault does not act as such a barrier. Particle tracking for the model indicates that despite the reduced water volume in the aquifer after decades of groundwater extraction, flow still occurs across the hinge of the Cedar Mesa anticline, accelerated by active pumping wells located west of the anticline axis. The model indicates that prior to the activation of the pumping wells, outflow from the C-aquifer would have occurred with greater frequency to Lyman Lake and along the extent of the Little Colorado River located downstream from the lake. The study also identified a zone of high hydraulic conductivity located between the Cedar Mesa anticline and the Coyote Wash fault that continues west of the Coyote Wash fault and may align with the Buttes anticline. This model of groundwater flow conditions improves the understanding of the complex subsurface geology and groundwater flow dynamics in the area.

In the Paria Plateau area of northern Arizona and southern Utah the Chinle formation of Upper Triassic age consists of a thick series of Ienticular sandstone, siltstone, claystone, and limestone. The series thins northwestward from about 900 feet at Lees Ferry, Ariz., to about 800 feet at Paria, Utah. Four members of the Chinle formation are recognized—1) the basal Shinarump member composed of conglomeratic sandstone and subordinate shale, 2) a unit, herein named the Lowery Spring member, composed of sandstone and mudstone, 3) the Petrified Forest member composed of bentonitic siltstone and claystone and thin sandstone, and 4) the Owl Rock member composed of cherty limestone and calcareous siltstone. Only the Petrified Forest member is present at all localities in the Paria Plateau area. The Shinarump member was deposited in topographic low areas on an erosion surface and its distribution is irregular. The Lowery Spring and Owl Rock members grade and pinch-out toward the northwest and are not present at Paria, Utah. The upper contact of the Chinle formation is locally unconformable. The three lowermost members were deposited on a broad, flat plain between the Cordilleran geosyncline and highlands to the southeast. In Owl Rock time the rising Cordilleran geanticline cut off the north-westward drainage of Chinle streams and a depositional basin trending southwest was formed.

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Conclusions drawn from a water resources study of the woody mountain area are: the average coefficients of transmissibility and of storage of the principal aquifer are approximately 30,000 gpd/ft and 0.05 respectively; drawdown in wells is greater than predicted using theoretical calculations due to the turbulent flow near the well bore in the fractured Coconino aquifer; the computed interference between pumped wells in the field ranges from 10.5 ft. To 19.7 ft. Interference would be negligible between wells spaced at distances greater than 6,000 ft. For pumping periods as long as two hundred days; the negative boundary effect of off-set on the oak creek fault may be balanced by the recharge effect of groundwater located in the highly permeable fractured zone adjacent to the fault; and the quantity of recharge water to the well field is greater than withdrawals from the wells.