Aquifer monitoring in the Big Chino Valley, Arizona
For this project gravity stations were collocated with monitoring wells to determine the storage/groundwater-level relation
Monitoring Minute 319 storage change
Gravity surveys were used to map infiltrated water during the Minute 319 “Pulse Flow” on the Colorado River
Mapping the Leupp, Arizona alluvial aquifer
Relative-gravity surveys were carried out to map the extent of the alluvial aquifer beneath the Little Colorado River
Tucson aquifer monitoring
The Southwest Gravity Program operates an A-10 absolute gravimeter, a rugged, field-portable instrument
The Southwest Gravity Program provides high-precision time-lapse gravity (repeat microgravity) data for hydrologic studies in the southwestern US. Recent projects include monitoring recharge underneath ephemeral-stream channels, monitoring aquifer-storage change in unconfined and compressible aquifers, measuring storage change at surface-spreading and injection-well artificial-recharge facilities, and estimating specific yield through the correlation of gravity and water-level change in wells. Projects range in scale from the site-specific (individual recharge basins) to regional (for example, the Tucson, Albuquerque, and Phoenix groundwater basins).
![Image showing map of current and past projects of the USGS Southwest Gravity Program](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/SGP_map.png?itok=I2jD2K_0)
Gravity is affected by mass: the greater an object's mass, the stronger its gravitational pull. By measuring changes in gravity over time, inferences can be made about changes in mass. In hydrology, this can be used to study water in the subsurface. If the amount of groundwater in a particular area increases, through processes such as rainfall infiltration and aquifer recharge, gravity will also increase. Likewise, losses of groundwater storage, such as from pumping, discharge to streams, and evaporation, will cause gravity to decrease.
Data are usually collected in project-specific monitoring networks, using absolute gravity meters and relative gravity meters. Changes in gravity, measured as an acceleration (for example, m/s2), are readily converted to a thickness of free-standing water using the “Bouguer,” or infinite-slab, approximation. Data are published as Sciencebase Data Releases and in an online absolute-gravity database. Data releases are primarily network-adjusted (combined) relative- and absolute-gravity data.
![Diagram showing a cone-shaped region of sensitivity underneath a gravity meter.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/Gravity_sensitivity.png?itok=dqthhuEE)
The Southwest Gravity Program provides GSadjust software, for the network adjustment of relative- and absolute-gravity data. The software is designed to work with Scintrex and Burris relative-gravity data formats (also, free-format csv data can be entered) and Micro-g Lacoste absolute-gravity formats. GSadjust provides various drift correction options for relative-gravity data and can compute gravity change between surveys. GSadjust is optimized for data interaction, allowing the user to quickly see the effect of choices made during data processing (for example, choice of drift-correction method) on the adjusted gravity values. Also, an Excel Spreadsheet is available that calculates drift correction and gravity differences between stations.
Forecasting Total Dissolved Solids Concentrations of Groundwater from the Lower Colorado Water Supply Project
Aquifer-storage monitoring at Tucson Water’s Heritage Project
Aquifer storage-change monitoring in Albuquerque Basin, New Mexico
Aquifer storage-change monitoring in the Big Chino Subbasin, Yavapai County, Arizona
Monitoring aquifer-storage change at Tucson Water's Southeast Houghton Area Recharge Project
North Phoenix aquifer monitoring with repeat microgravity
Aquifer-Storage Change and Land-Surface Elevation Change Monitoring in the Tucson Active Management Area
Monitoring Network of the Groundwater Flow System and Stream-Aquifer Relations in the Mesilla Basin, Doña Ana County, New Mexico and El Paso County, Texas
Southwest Gravity Program Absolute-Gravity Database (updated 2022-07-08)
Repeat microgravity data from Santa Cruz River, Tucson, Arizona, 2019-2022
MODFLOW-NWT groundwater model demonstrating groundwater model calibration with repeat microgravity measurements
Repeat microgravity data from Santa Cruz River, Tucson, Arizona, 2019-2021
Repeat microgravity data from South Houghton Area Recharge Project, Tucson, Arizona, 2020-2022 (ver. 2.0, August 2024)
Repeat microgravity data from the Hualapai Valley, Mohave County, Arizona, 2008-2019
Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2021
Repeat microgravity data from Mesilla Valley, New Mexico, 2016-2018
Repeat microgravity data from Albuquerque and Bernalillo County, New Mexico, 2016-2021 (ver. 3.0, March 2023)
Gravity data from the Truxton area, northwestern Arizona
Repeat microgravity data from the Big Chino Subbasin, 2001-2017, Yavapai County, Arizona
Gravity Change from 2014 to 2015, Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona
Procedures for field data collection, processing, quality assurance and quality control, and archiving of relative- and absolute-gravity surveys
Monitoring aquifer-storage change from artificial recharge with repeat microgravity along Santa Cruz River, Tucson, Arizona, 2019–22
Heavy: Software for forward-modeling gravity change from MODFLOW output
Measuring basin-scale aquifer storage change and mapping specific yield in Albuquerque, New Mexico, USA, with repeat microgravity data
Aquifer storage change, 2018–2021, in the Big Chino Subbasin, Yavapai County, Arizona
Determining seasonal recharge, storage changes, and specific yield using repeat microgravity and water-level measurements in the Mesilla Basin alluvial aquifer, New Mexico, 2016–2018
Gravity surveys for estimating possible width of enhanced porosity zones across structures on the Coconino Plateau, Coconino County, north-central Arizona
Improving groundwater model calibration with repeat microgravity measurements
Assessing potential groundwater-level declines from future withdrawals in the Hualapai Valley, northwestern Arizona
Gravity surveys and depth to bedrock in the Truxton basin, northwestern Arizona
Aquifer storage change and storage properties, 2010–2017, in the Big Chino Subbasin, Yavapai County, Arizona
Groundwater-storage change and land-surface elevation change in Tucson Basin and Avra Valley, south-central Arizona--2003-2016
Changes in Earth’s gravity reveal changes in groundwater storage
Changes in Gravity used to Quantify Groundwater-Storage Change in the Tucson AMA
The Tucson Active Management Area (AMA) is a semi-arid region in southern Arizona. Historically, groundwater pumping in the Tucson AMA exceeded recharge for many decades. Gravity-based methods developed by the USGS can be used to directly measure groundwater-storage changes, providing an estimate of total storage change that does not rely on uncertain estimates of inflows and outflows.
Heavy
Gravity Data Spreadsheets
GSadjust: a graphical user interface for processing combined relative- and absolute-gravity surveys
GSadjust is a graphical user interface for processing relative-gravity surveys. It provides an interface for data selection, drift evaluation and correction, network adjustment, for data from modern relative (Scintrex, ZLS) and absolute (Micro-g LaCoste) gravity meters.
The Southwest Gravity Program provides high-precision time-lapse gravity (repeat microgravity) data for hydrologic studies in the southwestern US. Recent projects include monitoring recharge underneath ephemeral-stream channels, monitoring aquifer-storage change in unconfined and compressible aquifers, measuring storage change at surface-spreading and injection-well artificial-recharge facilities, and estimating specific yield through the correlation of gravity and water-level change in wells. Projects range in scale from the site-specific (individual recharge basins) to regional (for example, the Tucson, Albuquerque, and Phoenix groundwater basins).
![Image showing map of current and past projects of the USGS Southwest Gravity Program](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/SGP_map.png?itok=I2jD2K_0)
Gravity is affected by mass: the greater an object's mass, the stronger its gravitational pull. By measuring changes in gravity over time, inferences can be made about changes in mass. In hydrology, this can be used to study water in the subsurface. If the amount of groundwater in a particular area increases, through processes such as rainfall infiltration and aquifer recharge, gravity will also increase. Likewise, losses of groundwater storage, such as from pumping, discharge to streams, and evaporation, will cause gravity to decrease.
Data are usually collected in project-specific monitoring networks, using absolute gravity meters and relative gravity meters. Changes in gravity, measured as an acceleration (for example, m/s2), are readily converted to a thickness of free-standing water using the “Bouguer,” or infinite-slab, approximation. Data are published as Sciencebase Data Releases and in an online absolute-gravity database. Data releases are primarily network-adjusted (combined) relative- and absolute-gravity data.
![Diagram showing a cone-shaped region of sensitivity underneath a gravity meter.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/media/images/Gravity_sensitivity.png?itok=dqthhuEE)
The Southwest Gravity Program provides GSadjust software, for the network adjustment of relative- and absolute-gravity data. The software is designed to work with Scintrex and Burris relative-gravity data formats (also, free-format csv data can be entered) and Micro-g Lacoste absolute-gravity formats. GSadjust provides various drift correction options for relative-gravity data and can compute gravity change between surveys. GSadjust is optimized for data interaction, allowing the user to quickly see the effect of choices made during data processing (for example, choice of drift-correction method) on the adjusted gravity values. Also, an Excel Spreadsheet is available that calculates drift correction and gravity differences between stations.
Forecasting Total Dissolved Solids Concentrations of Groundwater from the Lower Colorado Water Supply Project
Aquifer-storage monitoring at Tucson Water’s Heritage Project
Aquifer storage-change monitoring in Albuquerque Basin, New Mexico
Aquifer storage-change monitoring in the Big Chino Subbasin, Yavapai County, Arizona
Monitoring aquifer-storage change at Tucson Water's Southeast Houghton Area Recharge Project
North Phoenix aquifer monitoring with repeat microgravity
Aquifer-Storage Change and Land-Surface Elevation Change Monitoring in the Tucson Active Management Area
Monitoring Network of the Groundwater Flow System and Stream-Aquifer Relations in the Mesilla Basin, Doña Ana County, New Mexico and El Paso County, Texas
Southwest Gravity Program Absolute-Gravity Database (updated 2022-07-08)
Repeat microgravity data from Santa Cruz River, Tucson, Arizona, 2019-2022
MODFLOW-NWT groundwater model demonstrating groundwater model calibration with repeat microgravity measurements
Repeat microgravity data from Santa Cruz River, Tucson, Arizona, 2019-2021
Repeat microgravity data from South Houghton Area Recharge Project, Tucson, Arizona, 2020-2022 (ver. 2.0, August 2024)
Repeat microgravity data from the Hualapai Valley, Mohave County, Arizona, 2008-2019
Repeat microgravity data from Tucson Basin and Avra Valley, Arizona, 2021
Repeat microgravity data from Mesilla Valley, New Mexico, 2016-2018
Repeat microgravity data from Albuquerque and Bernalillo County, New Mexico, 2016-2021 (ver. 3.0, March 2023)
Gravity data from the Truxton area, northwestern Arizona
Repeat microgravity data from the Big Chino Subbasin, 2001-2017, Yavapai County, Arizona
Gravity Change from 2014 to 2015, Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona
Procedures for field data collection, processing, quality assurance and quality control, and archiving of relative- and absolute-gravity surveys
Monitoring aquifer-storage change from artificial recharge with repeat microgravity along Santa Cruz River, Tucson, Arizona, 2019–22
Heavy: Software for forward-modeling gravity change from MODFLOW output
Measuring basin-scale aquifer storage change and mapping specific yield in Albuquerque, New Mexico, USA, with repeat microgravity data
Aquifer storage change, 2018–2021, in the Big Chino Subbasin, Yavapai County, Arizona
Determining seasonal recharge, storage changes, and specific yield using repeat microgravity and water-level measurements in the Mesilla Basin alluvial aquifer, New Mexico, 2016–2018
Gravity surveys for estimating possible width of enhanced porosity zones across structures on the Coconino Plateau, Coconino County, north-central Arizona
Improving groundwater model calibration with repeat microgravity measurements
Assessing potential groundwater-level declines from future withdrawals in the Hualapai Valley, northwestern Arizona
Gravity surveys and depth to bedrock in the Truxton basin, northwestern Arizona
Aquifer storage change and storage properties, 2010–2017, in the Big Chino Subbasin, Yavapai County, Arizona
Groundwater-storage change and land-surface elevation change in Tucson Basin and Avra Valley, south-central Arizona--2003-2016
Changes in Earth’s gravity reveal changes in groundwater storage
Changes in Gravity used to Quantify Groundwater-Storage Change in the Tucson AMA
The Tucson Active Management Area (AMA) is a semi-arid region in southern Arizona. Historically, groundwater pumping in the Tucson AMA exceeded recharge for many decades. Gravity-based methods developed by the USGS can be used to directly measure groundwater-storage changes, providing an estimate of total storage change that does not rely on uncertain estimates of inflows and outflows.
Heavy
Gravity Data Spreadsheets
GSadjust: a graphical user interface for processing combined relative- and absolute-gravity surveys
GSadjust is a graphical user interface for processing relative-gravity surveys. It provides an interface for data selection, drift evaluation and correction, network adjustment, for data from modern relative (Scintrex, ZLS) and absolute (Micro-g LaCoste) gravity meters.