About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

GCAGS Transactions


Gulf Coast Association of Geological Societies Transactions
Vol. 44 (1994), Pages 185-192

Use of Aquifer Stratigraphy for Building Numerical Models of Ground-Water Flow: Case Study of the Heterogeneous Gulf Coast Aquifer in Matagorda and Wharton Counties, Texas

Alan R. Dutton


Aquifer stratigraphy, hydrologic properties, and ground-water availability are complexly interrelated in the heterogeneous Gulf Coast aquifer. The aquifer is made up of a basinward-thickening wedge of Pliocene and Pleistocene formations deposited in fluvial meanderbelt, fluvio-deltaic, and wave-dominated delta systems. To evaluate ground-water resources in the aquifer underlying Matagorda and Wharton Counties, Texas, a quasi-three-dimensional numerical model was devised that accounts for aquifer heterogeneity. Transmissivity, storativity, and compaction potential were assigned to model blocks as functions of sand percentage mapped for each aquifer unit. Transmissivity, vertical conductance, river leakage rates, and head-dependent recharge and discharge rates were then adjusted to match simulated and "observed prepumping" hydraulic heads. Storativities were adjusted to match simulated and "historic" hydraulic heads. The model predicts that hydraulic head locally will fall below the tops of confined aquifers and that land-surface subsidence might increase locally to as much as 2.5 ft by 2030. The model also indicates that 12 percent of the historical decrease in stored water is nonrecoverable because of clay-bed compaction.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24