This hydrogeologicmodeling study has been performed aspart of the regional hydrologiccharacterization of the Waste Isolation PilotPiVant(WIPP) sltein southeastern New Mexico.The studyhasproducedan estimation ofthe transmissivity and Darcy-velocity distributions in the CulebraDolomiteMember of the Permian Rustier Formationatthe WIPP site. The results ofthis studyareintendedtosupport SandiaNational Laboratories performance-assessment calculations. The three-dimensional finite-difference codeSWIFT IIwas employedforthe numerical modeling, usinga variable-fluid-density and single-porosity formulation. The spatial scale ofthemodel,21.3km by 30.6km, was chosento allow simulation ofregional-scale pumping tests conductedat t_he H-3 and H-11 hydropadsand theWIPP-13 borehole, which arelocated south,southeast, and northwest, respectively, ofthe centerofthe WIPP site. The modeledareaincludes and extends beyond thecontrolled areadefined by theWIPP-site boundaries.