Images

A borehole extensometer is an instrument that measures vertical land motion caused by changes in aquifer thickness. A borehole is drilled through the entirety of an aquifer system and the steel pipe is anchored at the base to the basement rock.

Borehole Extensometer

Borehole extensometers are highly sensitive instruments which measure aquifer compaction. This infographic explains the various parts of a borehole extensometer, and is modeled after the USGS extensometer at Nansemond, Virginia.

Glacial isostacy is the upward or downward land motion caused by the weight of ice sheets deforming the Earth's crust. The weight of the ice sheet deforms the underlying crust downward and displaces the underlying lithosphere, creating an indentation.

Collecting water quality samples from the New River Gorge in support of USGS-NPS partnership.

Fall 2022 Photo Contest Winner: Matt Kearns, USGS at Work category

Streambank erosion is a common problem in urban watersheds. This heavily eroded streambank is located within the Long Branch watershed in Fairfax County, Virginia. This site is monitored as a part of the Fairfax County Water Resources Monitoring Network.

A floodplain monitoring site along the Long Branch stream. This site is monitored as a part of the Fairfax County Water Resources Monitoring Network.

Streambank erosion is a common problem in urban watersheds. This heavily eroded streambank is located within the Long Branch watershed in Fairfax County, Virginia. This site is monitored as a part of the Fairfax County Water Resources Monitoring Network.

A floodplain monitoring site along the Long Branch stream. In this photo, sediment is being deposited in-channel behind a downed tree.

This site is monitored as a part of the Fairfax County Water Resources Monitoring Network.

Streambank erosion is a common problem in urban watersheds. This heavily eroded streambank is located within the Long Branch watershed in Fairfax County, Virginia. This site is monitored as a part of the Fairfax County Water Resources Monitoring Network.

Water-quality samples collected as part of a sampling campaign across the Potomac River watershed. Water-quality analyses are time-sensitive. At the end of each sampling day, samples are shipped overnight to the respective water-quality labs.

Antietam Creek below Hagerstown, Maryland (U.S. Geological Survey site identifier 01619270).

This map shows the locations of the four existing extensometers (red) in the USGS' Virginia Extensometer Network with the location of a fifth future extensometer (green). The basemap is of the Virginia Coastal Plain and shows the severity of groundwater depletion, with darker blue indicating greater groundwater depletion. 

USGS scientist Doug Moyer capturing an elevated stage (storm-impacted) water quality sample at the South Fork Shenandoah River near Lynnwood, VA.

Data for this monitoring site can be found at USGS Water Data for the Nation.

This animated infographic shows how aquifer compaction can lead to land subsidence. When water is pumped from a confined aquifer faster than it can recharge, the water pressure in the aquifer begins to decrease. As water pressure decreases, both the confining layers and the aquifers themselves can start to compact under the weight of the overlying sediments.

What are PFAS?

The USGS Nansemond pipe extensometer (59D 39) with a total depth of 1,960 feet. Data for this site can be found on USGS Water Data for the Nation.

Hydrologic technician Erik Kaseloo collecting a water quality sample from Indian Run in Fairfax County. Part of the Fairfax County Water Resources Monitoring Network.

Data for this site can be found at USGS Water Data for the Nation.

A USGS scientist measures stream discharge at The Glade, an urban stream in Reston, Virginia.

This photograph shows a high-accuracy geodetic surveying tripod used to measure vertical land motion.

A USGS scientist samples for benthic macroinvertebrates at Snakeden Branch, Reston, VA

USGS scientists conduct benthic macroinvertebrate sampling at The Glade in Reston, Virginia