USGS scientists are using high-resolution handheld and airborne thermal imaging cameras in groundwater/surface-water exchange studies and other investigations where surface temperature contrasts indicate various hydrological processes. These cameras are used to quickly locate and characterize thermal (temperature) anomalies along streams, lakes, wetlands, estuaries, and across the landscape. Variations in temperature can be used to track the heat carried by flowing water, such as groundwater discharge into a stream, pinpointing zones of water exchange and water mixing for further analysis.
Overview
USGS scientists are using thermal infrared cameras to image the surface of water features and adjacent structures (e.g., banks, bars, seeps, etc.) to quickly locate and characterize thermal (temperature) anomalies in real-time at scales ranging from centimeters to kilometers. Thermal infrared cameras capture images of the surface temperature of targets in their field of view. High-resolution thermal imaging cameras are useful for locating focused groundwater discharge to the land surface and surface water. These sensors can be used in support of other studies where water thermal signatures are of interest, such as stream confluence mixing and evaluation of thermal refugia. Among a wide range of hydrologic applications, thermal infrared data can be used to:
- pinpoint locations of groundwater discharge and infer high versus lower discharge rates,
- map river surface thermal profiles,
- assess water mixing zones and discrete cold water aquatic habitats, and
- optimize selection of direct sampling and monitoring locations.
Although thermal imaging for water-resources studies is common using satellite or traditional crewed aircraft, the availability and wider integration of robust, small, high-resolution thermal imaging tools in support of USGS groundwater studies is more recent. Currently USGS hydrologists are deploying thermal infrared cameras locally in multiple ways, including:
- By hand: The small size of handheld cameras makes them convenient and efficient tools for studies in locations ranging from dense urban settings to remote field sites.
- On fixed mounts: Cameras installed at streamgages and bridges enable continuous thermal imaging for real-time monitoring to inform our understanding of changing site conditions at daily to seasonal scales.
- From small drones: Low-altitude thermal infrared data collected by small drones (small unoccupied/uncrewed aircraft systems, or sUAS) enables continuous and repeatable spatial characterization of water-surface temperature at the project scale. Drones can enable data collection at locations that might otherwise be unsafe or difficult to reach and (or) that have strong water-surface thermal infrared reflection.
Additional interdisciplinary applications are being explored by the USGS Water Resources Mission Area and across USGS.


Learn More: Heat as a Tracer of Water Movement and Exchange at the Land Surface
Current USGS use of thermal infrared cameras builds on a long history of USGS research on using water temperature to help understand the movement of and exchange of water at the land surface. Temperature is a fundamental water-quality parameter, impacting chemical reaction, gas solubility, microbial reactivity, and aquatic animal metabolic rates. Water temperature anomalies and contrasts throughout aquatic systems can also be used to trace physical hydrologic processes, such as inflows of groundwater and tributaries. Figures below show how thermal infrared imaging can be used to rapidly identify, visualize, and quantify differences in water temperature that may indicate groundwater discharging to the surface of a streambank and seeping to the adjacent stream channel. To learn more about use of heat as a tracer, refer to "Heat as a tool for studying the movement of ground water near streams" and the research papers linked on the Related Publications tab of this page.
The USGS has trained scientists, provided equipment, and sponsored handheld thermal imaging camera technology demonstration and evaluation projects. A few examples of applications and related research are included below.
Geophysics for USGS Groundwater/Surface Water Exchange Studies
Thermal Imaging Camera Use: Identifying Groundwater Inputs to a Reef in American Samoa
Links below are to some examples of USGS data releases including thermal infrared imaging for groundwater studies.
Thermal infrared images of groundwater discharge zones in the Farmington and Housatonic River watersheds (Connecticut and Massachusetts, 2019)(ver. 3.0, January 2023)
Thermal infrared and photogrammetric data collected by drone for hydrogeologic characterization around two US Geological Survey Next Generation Water Observing Systems stream gage locations near Claryville, NY, USA
Thermal infrared, multispectral, and photogrammetric data collected by drone for hydrogeologic analysis of the East River and Coal Creek beaver-impacted corridors near Crested Butte, Colorado
Thermal infrared and photogrammetric data collected by small unoccupied aircraft system for hydrogeologic analysis of Oh-be-joyful Creek, Gunnison National Forest, Colorado, August 2017
Below are examples of USGS publications using thermal imaging cameras for groundwater studies.
Efficient hydrogeological characterization of remote stream corridors using drones
GW/SW-MST: A groundwater/surface-water method selection tool
Exploring local riverbank sediment controls on the occurrence of preferential groundwater discharge points
An ecohydrological typology for thermal refuges in streams and rivers
Groundwater discharges as a source of phytoestrogens and other agriculturally derived contaminants to streams
Evaluation of stream and wetlands restoration using UAS-based thermal infrared mapping
Return flows from beaver ponds enhance floodplain-to-river metals exchange in alluvial mountain catchments
Efficient hydrogeological characterization of remote stream corridors using drones
Longitudinal thermal heterogeneity in rivers and refugia for coldwater species: Effects of scale and climate change
A comparison of thermal infrared to fiber-optic distributed temperature sensing for evaluation of groundwater discharge to surface water
Understanding water column and streambed thermal refugia for endangered mussels in the Delaware River
Heat as a tool for studying the movement of ground water near streams
Determining temperature and thermal properties for heat-based studies of surface-water ground-water interactions: Appendix A of Heat as a tool for studying the movement of ground water near streams (Cir1260)
Links below include USGS software related to thermal imaging for groundwater studies.
GW/SW-MST: A Groundwater/Surface-Water Method Selection Tool
- Overview
USGS scientists are using high-resolution handheld and airborne thermal imaging cameras in groundwater/surface-water exchange studies and other investigations where surface temperature contrasts indicate various hydrological processes. These cameras are used to quickly locate and characterize thermal (temperature) anomalies along streams, lakes, wetlands, estuaries, and across the landscape. Variations in temperature can be used to track the heat carried by flowing water, such as groundwater discharge into a stream, pinpointing zones of water exchange and water mixing for further analysis.
Overview
Sources/Usage: Public Domain. Visit Media to see details.Thermal infrared camera used to monitor temperature on the surface of the Neversink River at Claryville, New York, USGS streamgage site 01435000. Images from this camera can be viewed and downloaded from the USGS Hydrologic Imagery Visualization and Information System (HIVIS) web site. USGS scientists are using thermal infrared cameras to image the surface of water features and adjacent structures (e.g., banks, bars, seeps, etc.) to quickly locate and characterize thermal (temperature) anomalies in real-time at scales ranging from centimeters to kilometers. Thermal infrared cameras capture images of the surface temperature of targets in their field of view. High-resolution thermal imaging cameras are useful for locating focused groundwater discharge to the land surface and surface water. These sensors can be used in support of other studies where water thermal signatures are of interest, such as stream confluence mixing and evaluation of thermal refugia. Among a wide range of hydrologic applications, thermal infrared data can be used to:
- pinpoint locations of groundwater discharge and infer high versus lower discharge rates,
- map river surface thermal profiles,
- assess water mixing zones and discrete cold water aquatic habitats, and
- optimize selection of direct sampling and monitoring locations.
Although thermal imaging for water-resources studies is common using satellite or traditional crewed aircraft, the availability and wider integration of robust, small, high-resolution thermal imaging tools in support of USGS groundwater studies is more recent. Currently USGS hydrologists are deploying thermal infrared cameras locally in multiple ways, including:
- By hand: The small size of handheld cameras makes them convenient and efficient tools for studies in locations ranging from dense urban settings to remote field sites.
- On fixed mounts: Cameras installed at streamgages and bridges enable continuous thermal imaging for real-time monitoring to inform our understanding of changing site conditions at daily to seasonal scales.
- From small drones: Low-altitude thermal infrared data collected by small drones (small unoccupied/uncrewed aircraft systems, or sUAS) enables continuous and repeatable spatial characterization of water-surface temperature at the project scale. Drones can enable data collection at locations that might otherwise be unsafe or difficult to reach and (or) that have strong water-surface thermal infrared reflection.
Additional interdisciplinary applications are being explored by the USGS Water Resources Mission Area and across USGS.
Remote image UrlSources/Usage: Public Domain. Visit Media to see details.Most recent thermal infrared image from camera installed to monitor temperature on the surface of the Neversink River at Claryville, New York. Images from this camera can be viewed and downloaded from the USGS Hydrologic Imagery Visualization and Information System (HIVIS) web site. Sources/Usage: Public Domain. Visit Media to see details.a) A thermal infrared orthomoasic image generated from drone-based data collected over a wetland in the Farmington River headwaters, Connecticut. The data indicate multi-scale preferential groundwater discharge processes. b) A drone-based thermal infrared orthomosaic image from a section of mainstem Farmington River that captured a midstream stormwater discharge and groundwater-rich tributary inflow. In both orthomosaics, reds and yellows are used to indicate relatively warmer surfaces, while blues and greens indicate relatively cooler surfaces. (The orthomosaics were made by combining many individual georeferenced thermal infrared images into a map with a uniform scale.) Source: Briggs and others, 2022. Learn More: Heat as a Tracer of Water Movement and Exchange at the Land Surface
Current USGS use of thermal infrared cameras builds on a long history of USGS research on using water temperature to help understand the movement of and exchange of water at the land surface. Temperature is a fundamental water-quality parameter, impacting chemical reaction, gas solubility, microbial reactivity, and aquatic animal metabolic rates. Water temperature anomalies and contrasts throughout aquatic systems can also be used to trace physical hydrologic processes, such as inflows of groundwater and tributaries. Figures below show how thermal infrared imaging can be used to rapidly identify, visualize, and quantify differences in water temperature that may indicate groundwater discharging to the surface of a streambank and seeping to the adjacent stream channel. To learn more about use of heat as a tracer, refer to "Heat as a tool for studying the movement of ground water near streams" and the research papers linked on the Related Publications tab of this page.
Thermal image displayed as an inset of the true-color photograph taken in the field. Thermal image indicates water temperature, where warmer temperatures are represented as red and cooler temperatures as blue. The image presents an area where cooler groundwater (blue) may be discharging along a warm stream bank in mid-summer. The photo spans an distance about 3 meters across. The temperature scale is in degrees Celsius. (Credit: USGS/Martin Briggs.) Thermal image indicates water temperature, where warmer temperatures are represented as red and cooler temperatures as blue. The image presents an area where warmer groundwater (red) may be discharging into a cooler (blue) stream in late fall at Tidmarsh Farms, Massachusetts. The image spans an distance about 6 meters across. Temperature is in degrees Celsius. (Credit: USGS/Martin Briggs.) - Science
The USGS has trained scientists, provided equipment, and sponsored handheld thermal imaging camera technology demonstration and evaluation projects. A few examples of applications and related research are included below.
Geophysics for USGS Groundwater/Surface Water Exchange Studies
Locating and quantifying exchanges of groundwater and surface water, along with characterizing geologic structure, is essential to water-resource managers and hydrologists for the development of effective water-resource policy, protection, and management. The USGS conducts applied research to evaluate the use of new or emerging hydrogeophysical tools and methods to improve our understanding of...Thermal Imaging Camera Use: Identifying Groundwater Inputs to a Reef in American Samoa
USGS scientists used a thermal camera in American Samoa to understand the effect of land-based contaminants on an adjacent coral reef lagoon ecosystem. The infrared (IR) camera was used to capture thermal images of the lagoon to look for temperature differences to understand the distribution of freshwater entering the lagoon and the circulation of the lagoon water at various tidal levels. - Data
Links below are to some examples of USGS data releases including thermal infrared imaging for groundwater studies.
Thermal infrared images of groundwater discharge zones in the Farmington and Housatonic River watersheds (Connecticut and Massachusetts, 2019)(ver. 3.0, January 2023)
Locations of focused (or ‘preferential’) groundwater discharge to surface water are often hydrologically and ecologically important, yet our ability to predict the spatial distribution and water quality of preferential riverbank discharges is limited at the scale of river networks. To advance the understanding of the physical controls on riverbank groundwater discharge processes, discharge zones cThermal infrared and photogrammetric data collected by drone for hydrogeologic characterization around two US Geological Survey Next Generation Water Observing Systems stream gage locations near Claryville, NY, USA
The U.S. Geological Survey (USGS) collected low-altitude (typically 200-350 ft above land surface) airborne thermal infrared, and visual imagery data via a multirotor, small unoccupied aircraft system (UAS or 'drone') deployed along the river corridor encompassing two U.S. Geological Survey Next Generation Water Observing Systems (NGWOS) stream gage locations near Claryville, NY, USA. One site isThermal infrared, multispectral, and photogrammetric data collected by drone for hydrogeologic analysis of the East River and Coal Creek beaver-impacted corridors near Crested Butte, Colorado
The U.S. Geological Survey collected low-altitude (typically 200-350 ft als) airborne thermal infrared, multispectral, and visual imagery data via a multirotor, small unoccupied aircraft system deployed along beaver-impacted sections of the East River and Coal Creek stream corridors, near the town of Crested Butte, CO. Visual imagery was collected in jpg format, and the images were compiled automaThermal infrared and photogrammetric data collected by small unoccupied aircraft system for hydrogeologic analysis of Oh-be-joyful Creek, Gunnison National Forest, Colorado, August 2017
The U.S. Geological Survey collected low-altitude airborne thermal infrared data and visual imagery via a multirotor, small unoccupied aircraft system deployed from the northern bank of Oh-be-joyful Creek and adjacent to the Peeler fault, approximately 6 kilometers northwest of the town of Crested Butte, in Gunnison National Forest, Colorado, on August 17, 2017. Thermal infrared still images were - Publications
Below are examples of USGS publications using thermal imaging cameras for groundwater studies.
Efficient hydrogeological characterization of remote stream corridors using drones
This project demonstrates the successful use of small unoccupied aircraft system (sUASs) for hydrogeological characterization of a remote stream reach in a rugged mountain terrain. Thermal infrared, visual imagery, and derived digital surface models are used to inform conceptual models of groundwater/surface‐water exchange and efficiently geolocate zones of preferential groundwater discharge thatAuthorsMartin A. Briggs, Cian B. Dawson, Christopher Holmquist-Johnson, Kenneth H. Williams, John W. LaneGW/SW-MST: A groundwater/surface-water method selection tool
Groundwater/surface-water (GW/SW) exchange and hyporheic processes are topics receiving increasing attention from the hydrologic community. Hydraulic, chemical, temperature, geophysical, and remote sensing methods are used to achieve various goals (e.g., inference of GW/SW exchange, mapping of bed materials, etc.), but the application of these methods is constrained by site conditions such as wateAuthorsSteven Hammett, Frederick Day-Lewis, Brett Russell Trottier, Paul M. Barlow, Martin A. Briggs, Geoffrey N. Delin, Judson Harvey, Carole D. Johnson, John W. Lane, D. O. Rosenberry, Dale D. WerkemaExploring local riverbank sediment controls on the occurrence of preferential groundwater discharge points
Groundwater discharge to rivers takes many forms, including preferential groundwater discharge points (PDPs) along riverbanks that are exposed at low flows, with multi-scale impacts on aquatic habitat and water quality. The physical controls on the spatial distribution of PDPs along riverbanks are not well-defined, rendering their prediction and representation in models challenging. To investigateAuthorsMartin A. Briggs, Kaetlyn Jackson, F. Liu, Eric Moore, Alaina Bisson, A. M. HeltonAn ecohydrological typology for thermal refuges in streams and rivers
Thermal refuges are thermally distinct riverscape features used by aquatic organisms during unfavorable thermal events, facilitating resilience in marginal environments. However, the thermal refuge concept is nebulous, and the often interchangeable use of the term ‘thermal refugia’ creates additional ambiguity. We argue that lexical differences resulting from divergent scholarly trainings hinder hAuthorsC. Sullivan, J. Vokoun, A. M. Helton, Martin A. Briggs, B. KurylykGroundwater discharges as a source of phytoestrogens and other agriculturally derived contaminants to streams
Groundwater discharge zones in streams are important habitats for aquatic organisms. The use of discharge zones for thermal refuge and spawning by fish and other biota renders them susceptible to potential focused discharge of groundwater contamination. Currently, there is a paucity of information about discharge zones as a potential exposure pathway of chemicals to stream ecosystems. Using thermaAuthorsTyler J. Thompson, Martin A. Briggs, Patrick J. Phillips, Vicki S. Blazer, Kelly Smalling, Dana W. Kolpin, Tyler WagnerEvaluation of stream and wetlands restoration using UAS-based thermal infrared mapping
Large-scale wetland restoration often focuses on repairing the hydrologic connections degraded by anthropogenic modifications. Of these hydrologic connections, groundwater discharge is an important target, as these surface water ecosystem control points are important to thermal stability, among other ecosystem services. However, evaluating the effectiveness of the restoration activities on establiAuthorsMark Harvey, Danielle Hare, Alex Hackman, Glorianna Davenport, Adam Haynes, Ashley Helton, John W. Lane, Martin BriggsReturn flows from beaver ponds enhance floodplain-to-river metals exchange in alluvial mountain catchments
River to floodplain hydrologic connectivity is strongly enhanced by beaver- (Castor canadensis) engineered channel water diversions. The hydroecological impacts are wide ranging and generally positive, however, the hydrogeochemical characteristics of beaver-induced flowpaths have not been thoroughly examined. Using a suite of complementary ground- and drone-based heat tracing and remote sensing meAuthorsMartin Briggs, Cheng-Hui Wang, Frederick Day-Lewis, Kenneth H. Williams, Wenming Dong, John LaneEfficient hydrogeological characterization of remote stream corridors using drones
This project demonstrates the successful use of small unoccupied aircraft system (sUASs) for hydrogeological characterization of a remote stream reach in a rugged mountain terrain. Thermal infrared, visual imagery, and derived digital surface models are used to inform conceptual models of groundwater/surface‐water exchange and efficiently geolocate zones of preferential groundwater discharge thatAuthorsMartin A. Briggs, Cian B. Dawson, Christopher Holmquist-Johnson, Kenneth H. Williams, John W. LaneLongitudinal thermal heterogeneity in rivers and refugia for coldwater species: Effects of scale and climate change
Climate-change driven increases in water temperature pose challenges for aquatic organisms. Predictions of impacts typically do not account for fine-grained spatiotemporal thermal patterns in rivers. Patches of cooler water could serve as refuges for anadromous species like salmon that migrate during summer. We used high-resolution remotely sensed water temperature data to characterize summer therAuthorsA.H. Fullerton, Christian E. Torgersen, J.J. Lawer, E. A. Steel, J. L. Ebersole, S.Y. LeeA comparison of thermal infrared to fiber-optic distributed temperature sensing for evaluation of groundwater discharge to surface water
Groundwater has a predictable thermal signature that can be used to locate discrete zones of discharge to surface water. As climate warms, surface water with strong groundwater influence will provide habitat stability and refuge for thermally stressed aquatic species, and is therefore critical to locate and protect. Alternatively, these discrete seepage locations may serve as potential point sourcAuthorsDanielle K Hare, Martin A. Briggs, Donald O. Rosenberry, Dave Boutt, John W. LaneUnderstanding water column and streambed thermal refugia for endangered mussels in the Delaware River
Groundwater discharge locations along the upper Delaware River, both discrete bank seeps and diffuse streambed upwelling, may create thermal niche environments that benefit the endangered dwarf wedgemussel (Alasmidonta heterodon). We seek to identify whether discrete or diffuse groundwater inflow is the dominant control on refugia. Numerous springs and seeps were identified at all locations whereAuthorsMartin A. Briggs, Emily B. Voytek, Frederick D. Day-Lewis, Donald O. Rosenberry, John W. LaneHeat as a tool for studying the movement of ground water near streams
Stream temperature has long been recognized as an important water quality parameter. Temperature plays a key role in the health of a stream’s aquatic life, both in the water column and in the benthic habitat of streambed sediments. Many fish are sensitive to temperature. For example, anadromous salmon require specific temperature ranges to successfully develop, migrate, and spawn [see Halupka andDetermining temperature and thermal properties for heat-based studies of surface-water ground-water interactions: Appendix A of Heat as a tool for studying the movement of ground water near streams (Cir1260)
Advances in electronics leading to improved sensor technologies, large-scale circuit integration, and attendant miniaturization have created new opportunities to use heat as a tracer of subsurface flow. Because nature provides abundant thermal forcing at the land surface, heat is particularly useful in studying stream-groundwater interactions. This appendix describes methods for obtaining the therAuthorsDavid A. Stonestrom, Kyle W. Blasch - Software
Links below include USGS software related to thermal imaging for groundwater studies.
GW/SW-MST: A Groundwater/Surface-Water Method Selection Tool
The Groundwater/Surface-Water Method Selection Tool (GW/SW-MST) is a spreadsheet-based tool to help practitioners identify methods for use in groundwater/surface-water (GW/SW) exchange and hyporheic studies. GW/SW exchange and hyporheic processes are topics receiving increasing attention from the hydrologic community. Hydraulic, chemical, temperature, geophysical, and remote sensing methods are u