Sam Caldwell joined the U.S. Geological Survey as a Pathways Student in 2018 and was converted to a hydrologist in 2019.
Sam's work is mainly centered on understanding groundwater dynamics in the Virginia Coastal Plain using groundwater level analysis, electromagnetic resistivity techniques, photogrammetry, and various scales and types of other remote sensing data.
Much of Sam's project work focuses on the Virginia Coastal Plain in Virginia Beach and the Eastern shore. He leads a groundwater level and specific conductivity monitoring network in Virginia Beach that includes an electromagnetic induction logging network to monitor for saltwater intrusion, as well as a groundwater quality sampling element. Additionally, he is responsible for an electromagnetic induction logging network on the Eastern Shore of Virginia to monitor for salwater intrusion. He also leads a water quality sampling effort in Suffolk, VA in collaboration with the Hampton Roads Sanitation District's SWIFT project monitoring how treated wastewater injected into the Potomac aqufer is affecting and moving through the nearby groundwater system. He has worked on several remote sensing and photogrammetry projects at a variety of scales with LSPIV, visual light, multispectral, and thermal infrared imagery.
Education and Certifications
B.A. in Geology, Amherst College (2016)
M.S. in Earth Sciences, Syracuse University (2018)
Science and Products
Land Subsidence on the Virginia Coastal Plain
Virginia Eastern Shore Groundwater Resources
Shapefiles of hydrogeologic unit extents and top-surface altitude contours used in the revised hydrogeologic framework for the Virginia Coastal Plain Southwest of the James River
Multispectral and visual photogrammetric data collected via sUAS: Back Bay National Wildlife Refuge, Virginia, July 2018
Revisions to the Virginia Coastal Plain hydrogeologic framework southwest of the James River
Geonarrative: Land Motion and Subsidence on the Virginia Coastal Plain
Along the coast of Virginia, the USGS and our partners are constantly monitoring our land and waters in new and innovative ways. In Virginia, scientists at the Virginia and West Virginia Water Sciences Center are drilling deep into the Earth to assess the impacts of groundwater use. By studying the impacts of groundwater use, scientists can determine associated risks, such as land subsidence.
Science and Products
- Science
Land Subsidence on the Virginia Coastal Plain
Land subsidence is a loss of ground elevation, often experienced as the ground slowly sinking over the course of years. In eastern Virginia, high rates of groundwater use is a major factor in the land subsidence affecting the area. The Virginia-West Virginia Water Science Center, with the help of our partners, has been monitoring land subsidence in the Virginia Coastal Plain since 1979 using a...Virginia Eastern Shore Groundwater Resources
Informed management of groundwater resources for the Eastern Shore of Virginia depends on the availability of detailed and up-to-date scientific information. The USGS and the Virginia Department of Environmental Quality are conducting a long-term cooperative study to enhance the understanding of groundwater resources in the sole-source aquifer system beneath Accomack and Northampton counties... - Data
Shapefiles of hydrogeologic unit extents and top-surface altitude contours used in the revised hydrogeologic framework for the Virginia Coastal Plain Southwest of the James River
A revision to the hydrogeologic framework of the Virginia coastal plain southwest of the James River was developed by USGS during 2019-2021. This revision includes modifications to existing understanding of the groundwater system in Prince George, Surry, Sussex, Isle of Wight, and Southampton counties and the cities of Franklin and Suffolk in southeast Virginia. This USGS data release contains a cMultispectral and visual photogrammetric data collected via sUAS: Back Bay National Wildlife Refuge, Virginia, July 2018
The U.S. Geological Survey collected multispectral and visible light imagery via a quadcopter, small unoccupied aircraft system (sUAS) deployed near Ashville Bridge Creek in Virginia Beach, VA. Approximately 0.25 sq mi surrounding U.S.Fish and Wildlife Service (USFWS) Back Bay National Wildlife Refuge along Ashville Bridge Creek approximately 0.5 mi south of Lotus Garden Park on July 17 and 18, 20 - Publications
Revisions to the Virginia Coastal Plain hydrogeologic framework southwest of the James River
New drilling information reveals that altitudes of some hydrogeologic units of the Virginia Coastal Plain aquifer system differ by as much as 50 feet (ft) from those previously known, namely the Aquia and Potomac aquifers, the Potomac confining zone, and the Nanjemoy-Marlboro and Saint Marys confining units. In addition, the lateral margins of some hydrogeologic units are located as much as severaAuthorsSamuel H. Caldwell, E. Randolph McFarland - Multimedia
- Web Tools
Geonarrative: Land Motion and Subsidence on the Virginia Coastal Plain
Along the coast of Virginia, the USGS and our partners are constantly monitoring our land and waters in new and innovative ways. In Virginia, scientists at the Virginia and West Virginia Water Sciences Center are drilling deep into the Earth to assess the impacts of groundwater use. By studying the impacts of groundwater use, scientists can determine associated risks, such as land subsidence.