Michelle Sneed is a hydrologist with the U.S. Geological Survey. She spent 25 years leading land subsidence research in the California Water Science Center and now serves as the Technical Support Coordinator for Groundwater Science in the Office of Quality Assurance.
Michelle received her BS and MS degrees in geology from California State University, Sacramento, where she subsequently taught geology classes for 10 years. While at the California Water Science Center, she published many studies of land subsidence related to fluid-pressure changes in areas throughout California and other areas in the Western U.S., which often had a focus on subsidence impacts to water-conveyance infrastructure. She is a member of the UNESCO Land Subsidence International Initiative, the recognized leader in promoting global land subsidence studies. At the Office of Quality Assurance, she serves as a technical-knowledge and point-of-contact resource to USGS scientists for all aspects of groundwater science. Michelle helps maintain and foster the exceptional quality of data and science for which the USGS is known and respected by helping scientists understand and comply with USGS and DOI policies, processes, and procedures, and by identifying and communicating technical advancements and risks.
Science and Products
Water-Level, Water-Quality and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins
Continuous Global Positioning System (CGPS) Stations
Spirit Leveling
Interferometric Synthetic Aperture Radar (InSAR)
Land Subsidence in the Santa Clara Valley
Subsidence in the Sacramento-San Joaquin Delta
Extensometers and Compaction
Mojave Land-Subsidence Studies
Land Subsidence in the Coachella Valley
Delta-Mendota Canal: Using Groundwater Modeling to Analyze Land Subsidence
Delta-Mendota Canal: Evaluation of Groundwater Conditions and Land Subsidence
Land Subsidence Along the California Aqueduct
MODFLOW 6 model and ensemble used in the simulation of groundwater flow and land-surface subsidence in the northern part of the Gulf Coast aquifer system, 1897-2018
Central Valley Hydrologic Model version 2 (CVHM2): Observation Data (Groundwater Level, Streamflow, Subsidence) from 1916 to 2018 (ver. 2.0, June 2023)
Global Positioning System Survey data for 2015, and Interferometric Synthetic Aperture Radar Data for 1995-2017, Coachella Valley, Riverside County, California
Detection and measurement of land-surface deformation, Pajaro Valley, Santa Cruz and Monterey counties, California, 2015–18
Measuring and interpreting multilayer aquifer-system compactions for a sustainable groundwater-system development
Characterization of groundwater recharge and flow in California's San Joaquin Valley from InSAR-observed surface deformation
Mapping the global threat of land subsidence
Detection and measurement of land subsidence and uplift using Global Positioning System surveys and interferometric synthetic aperture radar, Coachella Valley, California, 2010–17
Mitigating land subsidence in the Coachella Valley, California, USA: An emerging success story
Detection and measurement of land subsidence and uplift using interferometric synthetic aperture radar, San Diego, California, USA, 2016–2018
Evaluation of land subsidence and ground failures at Bicycle Basin, Fort Irwin National Training Center, California, 1992–2017
Land subsidence along the California Aqueduct in west-central San Joaquin Valley, California, 2003–10
Land subsidence
Geohydrology, geochemistry, and numerical simulation of groundwater flow and land subsidence in the Bicycle Basin, Fort Irwin National Training Center, California
Water-resources and land-surface deformation evaluation studies at Fort Irwin National Training Center, Mojave Desert, California
Science and Products
- Science
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Water-Level, Water-Quality and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins
Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273,000 in 1990 (Mojave Water Agency, 2004) to more than 453,000 in...Continuous Global Positioning System (CGPS) Stations
Measurements of elevations, aquifer-system compaction, and water levels are used to improve our understanding of the processes responsible for land-surface elevation changes. Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using continuous GPS (CGPS) measurements and campaign global positioning system (GPS) surveying.Spirit Leveling
Elevation or elevation-change measurements are fundamental to monitoring land subsidence, and have been measured by using interferometric synthetic aperture radar (InSAR), continuous GPS (CGPS) measurements, campaign global positioning system (GPS) surveying, and spirit-leveling surveying. The most precise measurements tend to be made using spirit-leveling surveys and extensometers. Spirit...Interferometric Synthetic Aperture Radar (InSAR)
Interferometric Synthetic Aperture Radar (InSAR) is an effective way to measure changes in land surface altitude. InSAR makes high-density measurements over large areas by using radar signals from Earth-orbiting satellites to measure changes in land-surface altitude at high degrees of measurement resolution and spatial detail (Galloway and others, 2000).Synthetic Aperture Radar (SAR) imagery is...Land Subsidence in the Santa Clara Valley
Throughout the late 1800s and into the 1920s when two thirds of the Santa Clara Valley had been irrigated, water flowed freely from wells. Water-level declines of more than 200 ft occurred in the Santa Clara Valley from the early 1900's to the mid 1960's (Fowler, 1981). Land subsidence was first detected in 1933 (Poland and Ireland, 1988). As the decades passed, groundwater levels continued to...Subsidence in the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin Delta is part of the San Francisco Estuary, home to a diverse flora and fauna, including several threatened and endangered species, has a large area of prime farmland, and serves as the hub of California's freshwater-delivery system that moves water from the wet north to the dry southern part of the State.Extensometers and Compaction
Extensometers measure the compaction and expansion of the aquifer system, providing depth-specific data that can help CAWSC scientists better understand the rate, extent, and at what depths in the system subsidence is occurring.Mojave Land-Subsidence Studies
Land subsidence has been ongoing in the dry lake beds throughout the Mojave and Morongo groundwater basins since the 1960s. In a study conducted from 2004 - 2009, continuous GPS stations were added to interferometric synthetic aperture radar (InSAR) methods to measure changes in land surface altitude.Land Subsidence in the Coachella Valley
Groundwater is an important water-supply source in the Coachella Valley. The demand for water has exceeded the deliveries of imported surface water, and groundwater levels have been declining as a result of increased pumping. A network of GPS stations has been set up in the valley to monitor subsidence resulting from declining groundwater levels.Delta-Mendota Canal: Using Groundwater Modeling to Analyze Land Subsidence
A numerical modeling approach was used to quantify groundwater conditions and land subsidence spatially along the Delta-Mendota Canal. In addition, selected management alternatives for controlling land subsidence were evaluated.Delta-Mendota Canal: Evaluation of Groundwater Conditions and Land Subsidence
In areas adjacent to the Delta-Mendota Canal (DMC), extensive groundwater withdrawal from the San Joaquin Valley aquifer system has caused areas of the ground to sink as much as 10 feet, a process known as land subsidence. This could result in serious operational and structural issues for the Delta-Mendota Canal (DMC). In response, the USGS is studying and providing information on groundwater...Land Subsidence Along the California Aqueduct
Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence. More than 80 percent of the identified subsidence in the United States is a consequence of human impact on subsurface water. - Data
MODFLOW 6 model and ensemble used in the simulation of groundwater flow and land-surface subsidence in the northern part of the Gulf Coast aquifer system, 1897-2018
The U.S. Geological Survey (USGS), in cooperation with the Harris-Galveston Subsidence District and Fort Bend Subsidence District, constructed a finite-difference numerical groundwater-flow model of the northern Gulf Coast aquifer region for 1897 through 2018 using MODFLOW 6 with the Newton formulation solver to simulate groundwater flow and land-surface subsidence. Model parameter estimation andCentral Valley Hydrologic Model version 2 (CVHM2): Observation Data (Groundwater Level, Streamflow, Subsidence) from 1916 to 2018 (ver. 2.0, June 2023)
This digital dataset includes three sets of observational data (groundwater level, streamflow, subsidence) used to calibrate the updated Central Valley Hydrologic Model (CVHM2)Global Positioning System Survey data for 2015, and Interferometric Synthetic Aperture Radar Data for 1995-2017, Coachella Valley, Riverside County, California
GPS data collection: GPS measurements were taken at 24 geodetic monuments during September 27-October 2, 2015. The GPS surveys generally followed established guidelines (Zilkoski and others, 1997), except that the data were processed with single-baseline, rather than multi-baseline, software. GPS measurements were recorded at the monuments on at least 2 different days during 1-hour observation per - Multimedia
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Detection and measurement of land-surface deformation, Pajaro Valley, Santa Cruz and Monterey counties, California, 2015–18
Land-surface deformation (subsidence) caused by groundwater withdrawal is identified as an undesirable result in the Pajaro Valley Water Management Agency’s Basin Management Plan and California’s Sustainable Groundwater Management Act. In Pajaro Valley, groundwater provides nearly 90 percent of the total water supply. To aid the development of sustainable groundwater management criteria, the U.S.AuthorsJustin T. Brandt, Marisa M. Earll, Michelle Sneed, Wesley R. HensonMeasuring and interpreting multilayer aquifer-system compactions for a sustainable groundwater-system development
Ever decreasing water resources and climate change have driven the increasing use of groundwater causing land subsidence in many countries. Geodetic sensors such as InSAR, GPS and leveling can detect surface deformation but cannot measure subsurface deformation. A single‐well, single‐depth extensometer can be used to measure subsurface deformation, but it cannot delineate the depths of major compaAuthorsWei-Chia Hung, Cheinway Hwang, Michelle Sneed, Yi-An Chen, Chi-Hua Chu, Shao-Hung LinCharacterization of groundwater recharge and flow in California's San Joaquin Valley from InSAR-observed surface deformation
Surface deformation in California's Central Valley (CV) has long been linked to changes in groundwater storage. Recent advances in remote sensing have enabled the mapping of CV deformation and associated changes in groundwater resources at increasingly higher spatiotemporal resolution. Here, we use interferometric synthetic aperture radar (InSAR) from the Sentinel‐1 missions, augmented by continuoAuthorsW.R. Neely, A.A. Borsa, J.A. Burney, M.C. Levy, F. Silverii, Michelle SneedMapping the global threat of land subsidence
Subsidence, the lowering of Earth's land surface, is a potentially destructive hazard that can be caused by a wide range of natural or anthropogenic triggers but mainly results from solid or fluid mobilization underground. Subsidence due to groundwater depletion (1) is a slow and gradual process that develops on large time scales (months to years), producing progressive loss of land elevation (cenAuthorsGerardo Herrera, Pablo Ezquerro, Roberto Tomás, Marta Béjar-Pizarro, Juan López-Vinielles, Mauro Rossi, Rosa M. Mateos, Dora Carreón-Freyre, John Lambert, Pietro Teatini, Enrique Cabral-Cano, Gilles Erkens, Devin Galloway, Wei-Chia Hung, Najeebullah Kakar, Michelle Sneed, Luigi Tosi, Hanmei Wang, Shujun YeDetection and measurement of land subsidence and uplift using Global Positioning System surveys and interferometric synthetic aperture radar, Coachella Valley, California, 2010–17
Groundwater has been a major source of agricultural, recreational, municipal, and domestic supply in the Coachella Valley of California since the early 1920s. Pumping of groundwater resulted in groundwater-level declines as large as 50 feet (ft) or 15 meters (m) by the late 1940s. Because of concerns that the declines could cause land subsidence, the Coachella Valley Water District (CVWD) and theAuthorsMichelle Sneed, Justin T. BrandtMitigating land subsidence in the Coachella Valley, California, USA: An emerging success story
Groundwater has been a major source of agricultural, municipal, and domestic water supply since the early 1920s in the Coachella Valley, California, USA. Land subsidence, resulting from aquifer-system compaction and groundwater-level declines, has been a concern of the Coachella Valley Water District (CVWD) since the mid-1990s. As a result, the CVWD has implemented several projects to address grouAuthorsMichelle Sneed, Justin T. BrandtDetection and measurement of land subsidence and uplift using interferometric synthetic aperture radar, San Diego, California, USA, 2016–2018
Land subsidence associated with groundwater-level declines is stipulated as an “undesirable effect” in California’s Sustainable Groundwater Management Act (SGMA), and has been identified as a potential issue in San Diego, California, USA. The United States Geological Survey (USGS), the Sweetwater Authority, and the City of San Diego, undertook a cooperative study to better understand the hydromechAuthorsJustin T. Brandt, Michelle Sneed, Wesley R. DanskinEvaluation of land subsidence and ground failures at Bicycle Basin, Fort Irwin National Training Center, California, 1992–2017
Groundwater has been pumped in the Bicycle Basin at Fort Irwin National Training Center since the 1960s, and the amount pumped has generally increased since the 1990s. After a large crack (approximately 0.5-kilometer long) formed at the surface of Bicycle Lake playa during 2005–06 in the area used as an aircraft runway, a monitoring study was initiated by the U.S. Geological Survey, in cooperationAuthorsJill N. Densmore, Kevin M. Ellett, Michelle Sneed, Justin T. Brandt, James F. Howle, Andrew Y. Morita, Rodrigo Borela, Antonio Bobet, Drew C. ThayerLand subsidence along the California Aqueduct in west-central San Joaquin Valley, California, 2003–10
Extensive groundwater withdrawal from the unconsolidated deposits in the San Joaquin Valley caused widespread aquifer-system compaction and resultant land subsidence from 1926 to 1970—locally exceeding 8.5 meters. The importation of surface water beginning in the early 1950s through the Delta-Mendota Canal and in the early 1970s through the California Aqueduct resulted in decreased groundwater pumAuthorsMichelle Sneed, Justin T. Brandt, Michael SoltLand subsidence
Land subsidence in the United States is inextricably linked to the development of groundwater—one of the Nation’s most valuable natural resources. More than 80 percent of the identified subsidence in the United States is a consequence of anthropogenic impact on water resources. Three processes account for most of the water-related subsidence—the compaction of aquifer systems, the drainage and subsAuthorsMichelle SneedGeohydrology, geochemistry, and numerical simulation of groundwater flow and land subsidence in the Bicycle Basin, Fort Irwin National Training Center, California
Groundwater pumping from Bicycle Groundwater Basin (referred to as Bicycle Basin) in the Fort Irwin National Training Center, California, began in 1967. From 1967 to December 2010, about 46,000 acre-feet of water had been pumped from the basin and transported to the Irwin Basin. During this time, not only did water levels in the basin decline by as much as 100 feet, the quality of the groundwaterAuthorsJill N. Densmore, Linda R. Woolfenden, Diane L. Rewis, Peter M. Martin, Michelle Sneed, Kevin M. Ellett, Michael Solt, David M. MillerWater-resources and land-surface deformation evaluation studies at Fort Irwin National Training Center, Mojave Desert, California
The U.S. Army Fort Irwin National Training Center (NTC), in the Mojave Desert, obtains all of its potable water supply from three groundwater basins (Irwin, Langford, and Bicycle) within the NTC boundaries (fig. 1; California Department of Water Resources, 2003). Because of increasing water demands at the NTC, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army, completed severalAuthorsJill N. Densmore, Justine E. Dishart, David M. Miller, David C. Buesch, Lyndsay B. Ball, Paul A. Bedrosian, Linda R. Woolfenden, Geoffrey Cromwell, Matthew K. Burgess, Joseph Nawikas, David O'Leary, Adam Kjos, Michelle Sneed, Justin T. Brandt - News