Two extensive plumes (combined area > 1000 km2) have been delineated within the Ogallala aquifer in the Southern High Plains, TX, USA. Salinity varies within the plumes spatially and increases with depth; Cl ranges from 50 to >500 mg 1-1. Variable-density flow modeling using SUTRA has identified three broad regions of upward cross-formational flow from the underlying evaporite units. The upward discharge within the modeled plume area is in the range of 10-4-10-5 m3 day-1, and the TDS concentrations are typically >3000 mg 1-1. Regions of increased salinity, identified within the Whitehorse Group (evaporite unit) underlying the Ogallala aquifer, are controlled by the structure and thickness variations relative to the recharge areas. Distinct flow paths, on the order of tens of km to >100 km in length, and varying flow velocities indicate that the salinization of the Ogallala aquifer has been a slow, ongoing process and may represent circulation of waters recharged during Pleistocene or earlier times. On-going pumping has had negligible impact on the salinity distribution in the Ogallala aquifer, although simulations indicate that the velocity distribution in the underlying units may have been affected to depths of 150 m after 30 years of pumping. Because the distribution of saline ground water in this region of the Ogallala aquifer is heterogeneous, careful areal and vertical characterization is warranted prior to any well-field development. (C) 2000 Elsevier Science B.V.
|Number of pages||21|
|Journal||Journal of Hydrology|
|State||Published - Nov 30 2000|
Bibliographical noteFunding Information:
Our research was supported by grants from the Geological Society of America, the American Association of Petroleum Geologists, the Kentucky Water Resources Research Institute, and the University of Kentucky Graduate School. The US Geological Survey and the Panhandle Groundwater Conservation District #3 provided in-kind support. We thank the Canadian River Municipal Water Authority, the City of Amarillo, R.W. Harden and Associates, and Lee Wilson and Associates for sharing data, and Cliff Voss and Terry Lahm for advice on modeling. Alan Dutton, Jeffrey Hanor, Bill Thomas, Steve Workman, and an anonymous reviewer provided thoughtful reviews. We appreciate the cooperation of the Eakin, Dawkins, Campbell, and McCain families for providing access to their windmills.
- Ogallala aquifer
- Southern High Plains
ASJC Scopus subject areas
- Water Science and Technology