My research, with Dr. Dutton, investigates hydrogeologic constraints
on the up-dip movement of saline water in the Carrizo-Wilcox aquifer, a major
confined aquifer beneath the Texas coastal plain. The cities of Bryan and
College Station, Texas, are the largest users of groundwater from the aquifer.
The updip, near-surface part of the Carrizo-Wilcox aquifer hosts freshwater in
permeable poorly cemented sandstones. Farther downdip lies saline groundwater
and oil and gas deposits in a geopressured zone.
For this study, I’m developing a vertical cross-sectional flow model of
variable density groundwater. The information used was extracted from a
calibrated, three-dimensional, regional model of groundwater resources
developed by the Texas Water Development Board. SUTRA, a variable-density
groundwater modeling program, is being used to (a) study the evolution of the
concentration profile in the aquifer, assuming displacement of connate seawater
by recharging freshwater, and (b) evaluate the sensitivity of the concentration
profile to formation dip, recharge rate, leakage rate from the geopressured
zone, well-field withdrawal rate, and hydrogeologic properties such as
permeability and dispersivity. The numerical model was built using the Argus
ONE modeling interface.
