Porous and permeable strata of the Deep-Basin Brine aquifer underlie bedded evaporites that are being considered as repositories for high-level nuclear waste isolation in the Palo Duro Basin, Texas Panhandle. Formation-water samples collected from four U.S.

Deep brine aquifers of the Palo Duro Basin, Texas Panhandle, ranging in depth from about 1,000 to 3,000 m below land surface, are underpressured compared with the shallow Ogallala aquifer. Two-dimensional simulations of flow in an east-west regional cross-sectional model through the basin permitted us to characterize regional ground-water flow, to investigate causes of underpressuring below the Evaporite aquitard, and to evaluate mechanisms of recharge and discharge to and from the Deep-Basin Brine aquifer.

Sandstone in the Travis Peak (Hosston) Formation has been extensively modified by burial diagenesis. Permeability in much of the formation has been reduced to less than 0.1 md as a result of compaction, extensive precipitation of authigenic minerals, and minor pressure solution. Thin zones of higher porosity and permeability occur mainly near the top of the formation; porosity and permeability decrease with depth below the top.