Marshall Gannett

My interests center on quantitative characterization and numerical simulation of regional-scale groundwater flow systems, quantification of ground-water and surface-water interactions, and understanding the hydrologic response to climate change and other external stresses


My recent focus has included development of a coupled groundwater and surface-water model for upper Deschutes Basin in central Oregon and on understanding the hydrogeology of groundwater-dependent ecosystems. Previous projects include development of a regional groundwater model and coupled management model for the upper Klamath Basin in Oregon and California, and basin-scale studies of the Willamette Valley in western Oregon.

During my tenure at the USGS I have focused on advancing the quantitative understanding of groundwater systems in the volcanic terrain of the Northwest, focusing on the relation between groundwater flow, the structural and depositional histories of volcanic basins, and the connections to biological and human systems. This work has been done as a series of large-scale investigations of major river basins in Oregon and northern California on which I served as principal investigator and project chief working with groups of scientists and technicians. During these projects staff have applied a broad array of scientific tools including surface and subsurface geologic mapping, surface and borehole geophysics, extensive collection and analysis of geologic and hydrologic data, isotopic analysis, and numerical modeling. This work has added to the understanding of groundwater flow at a wide range of scales in the Cascade Range and adjacent basins and has practical applications in other volcanic regions. The funding model for USGS water science centers is such that my work is largely driven by key science needs of natural resource agencies. I work collaboratively with other USGS researchers and scientists from regulatory and non-governmental agencies to ensure the results of my efforts have both practical and scientific value.