Michelle Sneed
Biography
Michelle Sneed is a hydrologist with the U.S. Geological Survey and has been with the California Water Science Center since 1994. She received her BS and MS degrees in geology from California State University, Sacramento, where she periodically teaches geology classes. She has published many studies of land subsidence related to fluid-pressure changes in areas throughout California and other areas in the Western U.S. Recent studies in the San Joaquin and Coachella Valleys explore the impact of subsidence on water-conveyance infrastructure. She is a member of the UNESCO Land Subsidence International Initiative, the recognized leader in promoting global land subsidence studies.
Science and Products
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 (...
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.
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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...
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 (...
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...
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.
Mapping 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...
Herrera, Gerardo; Ezquerro, Pablo; Tomás, Roberto; Béjar-Pizarro, Marta; López-Vinielles, Juan; Rossi, Mauro; Mateos, Rosa M.; Carreón-Freyre, Dora; Lambert, John; Teatini, Pietro; Cabral-Cano, Enrique; Erkens, Gilles; Galloway, Devin; Hung, Wei-Chia; Kakar, Najeebullah; Sneed, Michelle; Tosi, Luigi; Wang, Hanmei; Ye, Shujun
Detection 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,...
Sneed, Michelle; Brandt, Justin T. Mitigating 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...
Sneed, Michelle; Brandt, Justin T. Detection 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...
Brandt, Justin T.; Sneed, Michelle; Danskin, Wesley R.
Evaluation 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...
Densmore, Jill; Ellett, Kevin M.; Sneed, Michelle; Brandt, Justin T.; Howle, James F.; Morita, Andrew Y.; Borela, Rodrigo; Bobet, Antonio; Thayer, Drew C.
Land 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...
Sneed, Michelle; Brandt, Justin T.; Solt, Michael Land 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...
Sneed, Michelle
Geohydrology, 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...
Densmore, Jill N.; Woolfenden, Linda R.; Rewis, Diane L.; Martin, Peter M.; Sneed, Michelle; Ellett, Kevin M.; Solt, Michael; Miller, David M. Water-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...
Densmore, Jill; Dishart, Justine E.; Miller, David M.; Buesch, David C.; Ball, Lyndsay B.; Bedrosian, Paul A.; Woolfenden, Linda R.; Cromwell, Geoffrey; Burgess, Matthew K.; Nawikas, Joseph; O'Leary, David; Kjos, Adam; Sneed, Michelle; Brandt, Justin T.
Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California
Cache Creek Settling Basin was constructed in 1937 to trap sediment from Cache Creek before delivery to the Yolo Bypass, a flood conveyance for the Sacramento River system that is tributary to the Sacramento–San Joaquin Delta. Sediment management options being considered by stakeholders in the Cache Creek Settling Basin include sediment excavation...
Arias, Michelle R.; Alpers, Charles N.; Marvin-DiPasquale, Mark C.; Fuller, Christopher C.; Agee, Jennifer L.; Sneed, Michelle; Morita, Andrew Y.; Salas, Antonia
Land subsidence in the southwestern Mojave Desert, California, 1992–2009
Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. Increased demands on water supplies have caused groundwater-level declines of more than 100 feet (ft) in some areas of this desert between the 1950s and the 1990s (Stamos and others,...
Brandt, Justin T.; Sneed, Michelle Time-varying land subsidence detected by radar altimetry: California, Taiwan and north China
Contemporary applications of radar altimetry include sea-level rise, ocean circulation, marine gravity, and ice sheet elevation change. Unlike InSAR and GNSS, which are widely used to map surface deformation, altimetry is neither reliant on highly temporally-correlated ground features nor as limited by the available spatial coverage, and can...
Hwang, Cheinway; Yang, Yuande; Kao, Ricky; Han, Jiancheng; Shum, C.K.; Galloway, Devin L.; Sneed, Michelle; Hung, Wei-Chia; Cheng, Yung-Sheng; Li, Fei
Extensometer Hunters: Searching for Long-Lost Technologies in San Joaquin Valley
San Joaquin Valley: the final frontier. These are the voyages of the U.S. Geological Survey. Its weeklong mission: to explore strange new locations, to seek out abandoned scientific technologies, to boldly go where no scientist has gone before (at least in a few decades).
During Recent Droughts: Central Valley Groundwater Levels Reached Historical Lows and Land Subsidence Intensified
This year, groundwater levels in many wells in California’s Central Valley are at or below historical low levels. In addition, from 2007 through 2015, land subsidence that correlates to areas with large groundwater level declines has strongly increased in two large agricultural areas near the towns of El Nido and Pixley, according to a new article by the U.S. Geological Survey.
Renewed Land Subsidence Poses Risk to Water Infrastructure in California’s San Joaquin Valley
Extensive groundwater pumping from San Joaquin Valley aquifers is increasing the rate of land subsidence, or sinking. This large-scale and rapid subsidence has the potential to cause serious damage to the water delivery infrastructure that brings water from the north of the valley to the south where it helps feed thirsty cropland and cities.