The effects of longwall mining on the local ground water regime axe determined through field monitoring and numerical modeling. Field displacement data were obtained from multiple-position borehole extensometers (MPBX's) and survey monuments, combined with hydraulic drawdown and recovery tests completed both pre- and post-mining. Despite the development of significant mining-induced displacements, the resulting effect on long-term water budgets was surprisingly small. Coupled flow-deformation modeling of the site was able to adequately define the post-mining mechanical and hydraulic response, including resulting conductivity magnitudes and water budgets. Rock Mechanics, Daemen & Schultz (eds).