Marshall Gannett is a Scientist Emeritus at the USGS Oregon Water Science Center.
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.
Science and Products
Filter Total Items: 28
Groundwater, biodiversity, and the role of flow system scale
Groundwater-dependent ecosystems and species (GDEs) are found throughout watersheds at locations of groundwater discharge, yet not all GDEs are the same, nor are the groundwater systems supporting them. Groundwater moves along a variety of flow paths of different lengths and with different contributing areas, ranging from shorter local flow paths with low discharge and large seasonal variability t
Authors
Allison R Aldous, Marshall W. Gannett
Landscape controls on the distribution and ecohydrology of central Oregon springs
Small springs in semiarid landscapes are essential for maintaining aquatic biodiversity and supporting livestock grazing operations. However, little is known about controls on the distribution and physical characteristics of small springs, the aquatic species they support, or their sensitivity to disturbance. We address this information gap in the Crooked River subbasin, a tributary of the Deschut
Authors
Zach Freed, Allison Aldous, Marshall W. Gannett
Simulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon
This report describes a hydrologic model for the upper Deschutes Basin in central Oregon developed using the U.S. Geological Survey (USGS) integrated Groundwater and Surface-Water Flow model (GSFLOW). The upper Deschutes Basin, which drains much of the eastern side of the Cascade Range in Oregon, is underlain by large areas of permeable volcanic rock. That permeability, in combination with the lar
Authors
Marshall W. Gannett, Kenneth E. Lite, John C. Risley, Esther M. Pischel, Jonathan L. La Marche
Geothermal implications of a refined composition-age geologic map for the volcanic terrains of southeast Oregon, northeast California, and southwest Idaho, USA
Sufficient temperatures to generate steam likely exist under most of the dominantly volcanic terrains of southeast Oregon, northeast California, and southeast Idaho, USA, but finding sufficient permeability to allow efficient advective heat exchange is an outstanding challenge. A new thematic interpretation of existing state-level geologic maps provides an updated and refined distribution of the c
Authors
Erick Burns, Marshall W. Gannett, David R. Sherrod, Mackenzie K. Keith, Jennifer A. Curtis, James R. Bartolino, John A. Engott, Benjamin P. Scandella, Michelle A. Stern, Alan L. Flint
Groundwater levels, trends, and relations to pumping in the Bureau of Reclamation Klamath Project, Oregon and California
The use of groundwater to supplement surface-water supplies for the Bureau of Reclamation Klamath Project in the upper Klamath Basin of Oregon and California markedly increased between 2000 and 2014. Pre-2001 groundwater pumping in the area where most of this increase occurred is estimated to have been about 28,600 acre-feet per year. Subsequent supplemental pumping rates have been as high as 128,
Authors
Marshall W. Gannett, Katherine H. Breen
Geologic and geomorphic controls on the occurrence of fens in the Oregon Cascades and implications for vulnerability and conservation
Montane fens are biologically diverse peat-forming wetlands that develop at points of groundwater discharge. To protect these ecosystems, it is critical to understand their locations on the landscape and the hydrogeologic systems that support them. The upper Deschutes Basin has a groundwater flow system that supports baseflow in many rivers, but little is known about the wetland types and groundwa
Authors
A. Aldous, Marshall W. Gannett, Mackenzie K. Keith, James E. O'Connor
Effects of groundwater pumping on agricultural drains in the Tule Lake subbasin, Oregon and California
Since 2001, irrigators in the upper Klamath Basin have increasingly turned to groundwater to compensate for reductions in surface-water allocation caused by shifts from irrigation use to instream flows for Endangered Species Act listed fishes. The largest increase in groundwater pumping has been in and around the Bureau of Reclamation’s Klamath Irrigation Project, which includes the Tule Lake subb
Authors
Esther M. Pischel, Marshall W. Gannett
Evaluation of alternative groundwater-management strategies for the Bureau of Reclamation Klamath Project, Oregon and California
The water resources of the upper Klamath Basin, in southern Oregon and northern California, are managed to achieve various complex and interconnected purposes. Since 2001, irrigators in the Bureau of Reclamation Klamath Irrigation Project (Project) have been required to limit surface-water diversions to protect habitat for endangered freshwater and anadromous fishes. The reductions in irrigation d
Authors
Brian J. Wagner, Marshall W. Gannett
Analysis of 1997–2008 groundwater level changes in the upper Deschutes Basin, Central Oregon
Groundwater-level monitoring in the upper Deschutes Basin of central Oregon from 1997 to 2008 shows water-level declines in some places that are larger than might be expected from climate variations alone, raising questions regarding the influence of groundwater pumping, canal lining (which decreases recharge), and other human influences. Between the mid-1990s and mid-2000s, water levels in the ce
Authors
Marshall W. Gannett, Kenneth E. Lite
Spatial variability of the response to climate change in regional groundwater systems -- examples from simulations in the Deschutes Basin, Oregon
We examine the spatial variability of the response of aquifer systems to climate change in and adjacent to the Cascade Range volcanic arc in the Deschutes Basin, Oregon using downscaled global climate model projections to drive surface hydrologic process and groundwater flow models. Projected warming over the 21st century is anticipated to shift the phase of precipitation toward more rain and less
Authors
Michael S. Waibel, Marshall W. Gannett, Heejun Chang, Christina L. Hulbe
Evapotranspiration from marsh and open-water sites at Upper Klamath Lake, Oregon, 2008--2010
Water allocation in the Upper Klamath Basin has become difficult in recent years due to the increase in occurrence of drought coupled with continued high water demand. Upper Klamath Lake is a central component of water distribution, supplying water downstream to the Klamath River, supplying water for irrigation diversions, and providing habitat for various species within the lake and surrounding w
Authors
David I. Stannard, Marshall W. Gannett, Danial J. Polette, Jason M. Cameron, M. Scott Waibel, J. Mark Spears
Spatial patterns of March and September streamflow trends in Pacific Northwest Streams, 1958-2008
Summer streamflow is a vital water resource for municipal and domestic water supplies, irrigation, salmonid habitat, recreation, and water-related ecosystem services in the Pacific Northwest (PNW) in the United States. This study detects significant negative trends in September absolute streamflow in a majority of 68 stream-gauging stations located on unregulated streams in the PNW from 1958 to 20
Authors
Heejun Chang, Il-Won Jung, Madeline Steele, Marshall Gannett
Science and Products
- Publications
Filter Total Items: 28
Groundwater, biodiversity, and the role of flow system scale
Groundwater-dependent ecosystems and species (GDEs) are found throughout watersheds at locations of groundwater discharge, yet not all GDEs are the same, nor are the groundwater systems supporting them. Groundwater moves along a variety of flow paths of different lengths and with different contributing areas, ranging from shorter local flow paths with low discharge and large seasonal variability tAuthorsAllison R Aldous, Marshall W. GannettLandscape controls on the distribution and ecohydrology of central Oregon springs
Small springs in semiarid landscapes are essential for maintaining aquatic biodiversity and supporting livestock grazing operations. However, little is known about controls on the distribution and physical characteristics of small springs, the aquatic species they support, or their sensitivity to disturbance. We address this information gap in the Crooked River subbasin, a tributary of the DeschutAuthorsZach Freed, Allison Aldous, Marshall W. GannettSimulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon
This report describes a hydrologic model for the upper Deschutes Basin in central Oregon developed using the U.S. Geological Survey (USGS) integrated Groundwater and Surface-Water Flow model (GSFLOW). The upper Deschutes Basin, which drains much of the eastern side of the Cascade Range in Oregon, is underlain by large areas of permeable volcanic rock. That permeability, in combination with the larAuthorsMarshall W. Gannett, Kenneth E. Lite, John C. Risley, Esther M. Pischel, Jonathan L. La MarcheGeothermal implications of a refined composition-age geologic map for the volcanic terrains of southeast Oregon, northeast California, and southwest Idaho, USA
Sufficient temperatures to generate steam likely exist under most of the dominantly volcanic terrains of southeast Oregon, northeast California, and southeast Idaho, USA, but finding sufficient permeability to allow efficient advective heat exchange is an outstanding challenge. A new thematic interpretation of existing state-level geologic maps provides an updated and refined distribution of the cAuthorsErick Burns, Marshall W. Gannett, David R. Sherrod, Mackenzie K. Keith, Jennifer A. Curtis, James R. Bartolino, John A. Engott, Benjamin P. Scandella, Michelle A. Stern, Alan L. FlintGroundwater levels, trends, and relations to pumping in the Bureau of Reclamation Klamath Project, Oregon and California
The use of groundwater to supplement surface-water supplies for the Bureau of Reclamation Klamath Project in the upper Klamath Basin of Oregon and California markedly increased between 2000 and 2014. Pre-2001 groundwater pumping in the area where most of this increase occurred is estimated to have been about 28,600 acre-feet per year. Subsequent supplemental pumping rates have been as high as 128,AuthorsMarshall W. Gannett, Katherine H. BreenGeologic and geomorphic controls on the occurrence of fens in the Oregon Cascades and implications for vulnerability and conservation
Montane fens are biologically diverse peat-forming wetlands that develop at points of groundwater discharge. To protect these ecosystems, it is critical to understand their locations on the landscape and the hydrogeologic systems that support them. The upper Deschutes Basin has a groundwater flow system that supports baseflow in many rivers, but little is known about the wetland types and groundwaAuthorsA. Aldous, Marshall W. Gannett, Mackenzie K. Keith, James E. O'ConnorEffects of groundwater pumping on agricultural drains in the Tule Lake subbasin, Oregon and California
Since 2001, irrigators in the upper Klamath Basin have increasingly turned to groundwater to compensate for reductions in surface-water allocation caused by shifts from irrigation use to instream flows for Endangered Species Act listed fishes. The largest increase in groundwater pumping has been in and around the Bureau of Reclamation’s Klamath Irrigation Project, which includes the Tule Lake subbAuthorsEsther M. Pischel, Marshall W. GannettEvaluation of alternative groundwater-management strategies for the Bureau of Reclamation Klamath Project, Oregon and California
The water resources of the upper Klamath Basin, in southern Oregon and northern California, are managed to achieve various complex and interconnected purposes. Since 2001, irrigators in the Bureau of Reclamation Klamath Irrigation Project (Project) have been required to limit surface-water diversions to protect habitat for endangered freshwater and anadromous fishes. The reductions in irrigation dAuthorsBrian J. Wagner, Marshall W. GannettAnalysis of 1997–2008 groundwater level changes in the upper Deschutes Basin, Central Oregon
Groundwater-level monitoring in the upper Deschutes Basin of central Oregon from 1997 to 2008 shows water-level declines in some places that are larger than might be expected from climate variations alone, raising questions regarding the influence of groundwater pumping, canal lining (which decreases recharge), and other human influences. Between the mid-1990s and mid-2000s, water levels in the ceAuthorsMarshall W. Gannett, Kenneth E. LiteSpatial variability of the response to climate change in regional groundwater systems -- examples from simulations in the Deschutes Basin, Oregon
We examine the spatial variability of the response of aquifer systems to climate change in and adjacent to the Cascade Range volcanic arc in the Deschutes Basin, Oregon using downscaled global climate model projections to drive surface hydrologic process and groundwater flow models. Projected warming over the 21st century is anticipated to shift the phase of precipitation toward more rain and lessAuthorsMichael S. Waibel, Marshall W. Gannett, Heejun Chang, Christina L. HulbeEvapotranspiration from marsh and open-water sites at Upper Klamath Lake, Oregon, 2008--2010
Water allocation in the Upper Klamath Basin has become difficult in recent years due to the increase in occurrence of drought coupled with continued high water demand. Upper Klamath Lake is a central component of water distribution, supplying water downstream to the Klamath River, supplying water for irrigation diversions, and providing habitat for various species within the lake and surrounding wAuthorsDavid I. Stannard, Marshall W. Gannett, Danial J. Polette, Jason M. Cameron, M. Scott Waibel, J. Mark SpearsSpatial patterns of March and September streamflow trends in Pacific Northwest Streams, 1958-2008
Summer streamflow is a vital water resource for municipal and domestic water supplies, irrigation, salmonid habitat, recreation, and water-related ecosystem services in the Pacific Northwest (PNW) in the United States. This study detects significant negative trends in September absolute streamflow in a majority of 68 stream-gauging stations located on unregulated streams in the PNW from 1958 to 20AuthorsHeejun Chang, Il-Won Jung, Madeline Steele, Marshall Gannett