Foreword, Robert J. Creed and Trish St. Clair • Section I.- Geologic Framework • Introduction to the hydrogeology of the eastern Snake River Plain, Roy C. Bartholomay, Linda C. Davis, and Paul Karl Link • Pliocene and Quaternary stratigraphic architecture and drainage systems of the Big Lost Trough, northeastern Snake River Plain, Idaho, Jeffrey K. Geslin, Paul Karl Link, James W. Riesterer, Mel A. Kuntz, and C. Mark Fanning • Paleoenvironments of sedimentary interbeds in the Pliocene and Quaternary Big Lost Trough, eastern Snake River Plain, Idaho, Erick A. Bestland, Paul Karl Link, Marvin A. Lanphere, and Duane E. Champion • Subsurface volcanology at Test Area North and controls on groundwater flow, Dennis J. Geist, Rachel A. Ellisor, Elisa N. Sims, and Scott S. Hughes • Section II.- Sedimentary Systems • Sedimentologic and hydrologic characterization of surficial sedimentary facies in the Big Lost Trough, Idaho National Engineering and Environmental Laboratory, eastern Idaho, Linda E. Mark and Glenn D. Thackray • Late Quaternary highstands in the Mud Lake and Big Lost Trough subbasins of Lake Terreton, Idaho, Gary L. Gianniny, Glenn D. Thackray, Darrell S. Kaufman, Steven L. Forman, Michael J. Sherbondy, and Delda Findeisen • Holocene paleoflood hydrology of the Big Lost River, western Idaho National Engineering and Environmental Laboratory, Idaho, Dean A. Ostenaa, Daniel R.H. O'Connell, Roy A. Walters, and Robert J. Creed • Section III. Volcanic Rift Zones and Basalt Accumulation • Tension cracks, eruptive fissures, dikes, and faults related to late Pleistocene-Holocene basaltic volcanism and implications for the distribution of hydraulic conductivity in the eastern Snake River Plain, Idaho, Mel A. Kuntz, Steven R. Anderson, Duane E. Champion, Marvin A. Lanphere, and Daniel J. Grunwald • Morphology of inflated pahoehoe lavas and spatial architecture of their porous and permeable zones, eastern Snake River Plain, Idaho, John A. Welhan, Chad M. Johannesen, Kelly S. Reeves, Thomas M. Clemo, John A. Glover, and Kenneth W. Bosworth • Geochemical correlations and implications for the magmatic evolution of basalt flow groups at the Idaho National Engineering and Environmental Laboratory, Scott S. Hughes, Michael McCurry, and Dennis J. Geist • Accumulation and subsidence of late Pleistocene basaltic lava flows of the eastern Snake River Plain, Idaho, Duane E. Champion, Marvin A. Lanphere, Steven R. Anderson, and Mel A. Kuntz • Open-system evolution of a single episode of Snake River Plain magmatism, Dennis J. Geist, Elisa N. Sims, Scott S. Hughes, and Michael McCurry • Section IV. Groundwater Studies • Chemical characteristics of thermal water beneath the eastern Snake River Plain, Travis L. McLing, Robert W. Smith, and Thomas M. Johnson • Genesis of alteration of Quaternary basalts within a portion of the eastern Snake River Plain aquifer, Lee H. Morse and Michael McCurry • Stochastic simulation of aquifer heterogeneity in a layered basalt aquifer system, eastern Snake River Plain, Idaho, John A. Welhan, Thomas M. Clemo, and Edith L. G?go • Modeling groundwater flow and contaminant transport in the Snake River Plain aquifer: A stochastic approach, Edith L. G&eaute;go, Gary S. Johnson, Matthew R. Hankin, Allan H. Wylie, and John A. Welhan • Recirculating tracer test in fractured basalt, Robin E. Nimmer, Dale R. Ralston, Allan H. Wylie, and Gary S. Johnson • Section V. Bioremediation Studies • Characterization of microbial isolates from the Idaho National Engineering and Environmental Laboratory Test Area North aquifer: Identifying potential enzymatic pathways for toluene oxidation, Mary E. Watwood, William K. Keener, and William A. Smith • Effect of basalt heterogeneity on intrinsic bioremediation processes in groundwater, Allan H. Wylie, Dale R. Ralston, and Gary S. Johnson • Index • GSA Data Repository Item 2002041: Identification of basalt interflow zones with borehole geophysical and video logs at the Idaho National Engineering and Environmental Laboratory, Idaho: John A. Glover, John A. Welhan, and Linda L. Davis.