(GP/GT) for Additional Water Supply in the Lower Rio Grande

R. H. Wallace of the united states Geological Survey had earlier
noted the extremely low salinity ("fresh") water sands in the deep
Frio and Vicksburg formations in the eastern part of the Rio Grande
Embayment (Wallace, 1974). S. S. Papadopulos of the U.S.G.S.
demonstrated the hypothetical flow from a geopressured reservoir
using the area outlined by the growth faults in Hidalgo County
(Papadopulos, 1974). The Texas Bureau of Economic Geology (Bebout
and others, 1975) has conducted a number of studies, which included
the South Texas area, for the United states Department of Energy.
One of the most extensive studies of the area was conducted by the
Southwest Research Institute for the former United states Energy
Research and Development Administration (Swanson and Others, 1976).
Procedure
Numerous regional studies of the South Texas area have
resulted in the delineation of a number of geothermal-geopressure
"fairways," primarily defined by specific sediment packages, and
bracketed by major growth fault trends (Woodruff and others, 1982).
Three of these fairways occur in Hidalgo county: a western fairway
bounded by the Vicksburg fault trend in eastern starr County and
the McAllen fault, a central fairway outlined by the McAllen and
Donna faults, and an eastern fairway outlined by the Donna fault
and the Weslaco fault.
A preliminary evaluation of the three principal trends led to
the conclusion that only the central and eastern fairways
demonstrated sufficient potential for further investigation.
Although temperatures and pressures in the western fairway are very
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