Geohydrology and simulation of steady-state flow conditions in regional aquifer systems in Cretaceous and older rocks underlying Kansas, Nebraska, and parts of Arkansas, Colorado, Missouri, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming

Abstract

Regional aquifer systems of Cambrian through Lower Cretaceous sedimentary rocks were the focus of an investigation termed the Central Midwest regional aquifer-system analysis. The study area consists of about 370,000 square miles and extends from the foothills of the Rocky Mountains in Colorado to the Mississippi River in eastern Missouri and from South Dakota to the Ouachita, Arbuckle, and Wichita Mountains of Arkansas and Oklahoma. Geologically, the study area lies within the stable interior of the North American continent and is dominated structurally by broad basins and arches. Substantial crustal deformation along the Ouachita, Arbuckle, and Wichita Mountains in the south and the Rocky Mountains in the west was the major factor in defining the southern and western boundaries of the study area.

Simulating the Evolution of Fluid Underpressures in the Great Plains, by Incorporation of Tectonic Uplift and Tilting, with a Groundwater Flow Model

“…The ℎ values for the Mississippian geohydrologic unit range from 10 −4 to 10 −1 m d −1 within the upper part of the distribution shown in Figure 18, as described in Signor et al [16]. After some experimentation, ℎ for the Mississippian geohydrologic unit was set to 5 × 10 −3 m d −1 , which falls within the range cited in Signor et al [16]. Table 5 presents the final values from the model calibration.…”

“…The land surface for the first model, the 27 Ma model shown in Figure 14 Signor et al [16], Midcontinent, 1996 Figure 18: Hydraulic conductivity values used by Signor et al [16]. Permeability values in square feet from four maps by Signor et al [16] for hydrologic units in a study of the Great Plains of the modeled time from 40 Ma). This modeled duration to steady state is bracketed by the analytic solution given in Carslaw and Jaeger ( [17], Eq.…”

“…In considering the selection of permeability values for a regional study of the Great Plains, Signor et al [16] produced a series of maps of ℎ for each of their aquifer systems. Values of ℎ were computed from porosity values obtained from geophysical logs.…”