Joel B Sankey, Ph.D.
Joel Sankey is a Research Geologist for the USGS Southwest Biological Science Center (SBSC), and the Grand Canyon Monitoring and Research Center (GCMRC), in Flagstaff, Arizona.
I am also an adjunct professor of the School of Earth and Sustainability (SES) at Northern Arizona University. Previously, I was a Mendenhall Fellow with the USGS Western Geographic Science Center located at the University of Arizona in Tucson. I have a Ph.D. in Engineering and Applied Science from the Geosciences Department at Idaho State University.
Overall, my research focus is on geomorphic and ecosystem processes and function of rivers and upland environments. I characterize and interpret physical and biological land surface change that occurs contemporarily at intra-annual to decadal time scales. I study changes that occur as a function of soil erosion and sediment transport. I also study biophysical processes that change the distribution and composition of vegetation. Many of the land surface changes I study are driven by disturbances caused by people, fires, flooding, and wind. My work is directly relevant to either management actions that are implemented by humans to mitigate these disturbances (e.g., large-scale planting and seeding) or management actions that have either intentionally (e.g., controlled river floods; prescribed fires; removal of invasive vegetation) or unintentionally (e.g., climate change) produced the disturbance and therefore are drivers of change. Increasingly, my work focuses on forecasting how future changes in climate, weather, and hydrology, will affect ecosystems and management outcomes.
Much of my work incorporates remote sensing with digital imagery and topographic data acquired from multispectral and LiDAR sensors on ground-based, airborne (including manned and unmanned aerial vehicles (UAVs)), and satellite platforms. I also use detailed field-investigations for ecological and geomorphic assessment.
At the GCMRC, I lead the remote sensing group. I design our research and monitoring to be responsive to the Glen Canyon Dam Adaptive Management Program (GCDAMP), a Federal Advisory Committee chartered by the US Department of Interior and chaired by the Undersecretary for Water and Science.
Science and Products
Rio Grande 2012 Vegetation and Water Classification Data in the Big Bend Region
Northern Arizona Ponderosa Pine Forest Treatment Terrestrial Lidar Data
Riparian species vegetation classification data for the Colorado River within Grand Canyon derived from 2013 airborne imagery
River Valley Sediment Connectivity Data, Colorado River, Grand Canyon
Sand classifications along the Colorado River in Grand Canyon derived from 2002, 2009, and 2013 high-resolution multispectral airborne imagery
Meteorological Data for Selected Sites along the Colorado River Corridor, Arizona, 2014-2015
Remote sensing derived maps of tamarisk (2009) and beetle impacts (2013) along 412 km of the Colorado River in the Grand Canyon, Arizona
Climate, Wildfire, and Erosion Data, Western US
Water classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013Data
Riparian vegetation classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013Data
Four Band Multispectral High Resolution Image Mosaic of the Colorado River Corridor, Arizona - 2013
Geomorphic Process from Topographic FormData & Models
Can we accurately estimate sediment budgets on Mars?
Parks look for ways to alleviate Glen Canyon Dam’s dramatic downstream impacts
Woody plant encroachment of grassland and the reversibility of shrub dominance: Erosion, fire, and feedback processes
Carbon and ecohydrological priorities in managing woody encroachment: UAV perspective 63 years after a control treatment
Integrating airborne and mobile lidar data with UAV photogrammetry for rapid assessment of changing forest snow depth and cover
Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon
Biocrust and the soil surface: Influence of climate, disturbance, and biocrust recovery on soil surface roughness
Planetary defense preparedness: Identifying the potential for post-asteroid impact time delayed and geographically displaced hazards
Asteroid impacts - downwind and downstream effects
Preliminary assessment of carbon and nitrogen sequestration potential of wildfire-derived sediments stored by erosion control structures in forest ecosystems, southwest USA
Monitoring Tamarix changes using WorldView-2 satellite imagery in Grand Canyon National Park, Arizona
Future regulated flows of the Colorado River in Grand Canyon foretell decreased areal extent of sediment and increases in riparian vegetation
Science and Products
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Filter Total Items: 25
Rio Grande 2012 Vegetation and Water Classification Data in the Big Bend Region
These data are spatial polygon data and remote sensing image-based classification maps of surface water and vegetation species for 2012 along the Rio Grande River in Big Bend National Park in Texas. The geographic extent of the classification spans from the end of Mariscal Canyon to 5 km after the end of Boquillas Canyon, totaling approximately 77 Km of the river. The maps are also restricted to aNorthern Arizona Ponderosa Pine Forest Treatment Terrestrial Lidar Data
These are terrestrial laser scanner datasets collected in forested areas west of Flagstaff, Arizona in 2015 and 2016. For each of the two scanners, six treatment areas were scanned, with four of them overlapping one another (Figure 1). These data are composed of individual scans referenced to one another using reflective targets, and geolocated using differentially corrected GPS and RTK locationsRiparian species vegetation classification data for the Colorado River within Grand Canyon derived from 2013 airborne imagery
These data are a species-level classification map of riparian vegetation in the Colorado River riparian corridor in Grand Canyon, Arizona, USA. The classification is derived from 0.2 m pixel resolution multispectral aerial imagery acquired in May 2013. The classification spans the riparian zone of the river corridor between Glen Canyon Dam near Page, Arizona, and Lake Mead at Pearce Ferry, ArizonaRiver Valley Sediment Connectivity Data, Colorado River, Grand Canyon
This workbook contains spatial data on the hydrology, sedimentology, and vegetation extent within the Colorado River corridor from 60 to 78 miles (97 to 125 kilometers) downstream from Glen Canyon Dam, Arizona. In combination with the accompanying MATLAB scripts, these data were used to generate the results within the accompanying manuscript (Kasprak et al., Quantifying and Forecasting Changes inSand classifications along the Colorado River in Grand Canyon derived from 2002, 2009, and 2013 high-resolution multispectral airborne imagery
These data are remote sensing image-based classification maps of unvegetated river-derived sand along the Colorado River. One map is based on imagery acquired in May 2013 and is a classification of sand located above the wetted river channel in the imagery which was acquired at the approximate contemporary low-flow river discharge of 8,000 cubic feet per second (227 cubic meters per second) and exMeteorological Data for Selected Sites along the Colorado River Corridor, Arizona, 2014-2015
This data release presents records collected from six automated weather stations in operation between January 1, 2014 and December 31, 2015 within the Colorado River Corridor of Grand Canyon National Park and Glen Canyon National Recreation Area. Data collection locations, equipment configurations and methods follow those of the original report (OFR 2014-1247). These files are 4-minute interval daRemote sensing derived maps of tamarisk (2009) and beetle impacts (2013) along 412 km of the Colorado River in the Grand Canyon, Arizona
These data were compiled for quantifying the area of tamarisks (Tamarix spp.) in May 2009 and to quantify the area of beetle-impacted tamarisk in May 2013 within the 2009 tamarisk classification from Glen Canyon Dam to Separation Canyon, a total distance of 412 km along the Colorado River using the 2009 and 2013 0.2 m high-resolution airborne imagery datasets. We classified tamarisk presence in 20Climate, Wildfire, and Erosion Data, Western US
These data were used to examine how post-fire sedimentation might change in western USA watersheds with future fire from the decade of 2001-10 through 2041-50. The data include previously published projections (Hawbaker and Zhu, 2012a, b) of areas burned by future wildfires for several climate change scenarios and general circulation models (GCMs) that we summarized for 471 watersheds of the westeWater classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013Data
These data area classified maps of water in the Colorado River at a discharge of approximately 227 meters squared/second in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data are derived from interpretation of multispectral high resolution airborne imagery that was acquired in May 2013. The water classification data have the same 0.2-meter ground resolution as the imagery. ThesRiparian vegetation classification of the Colorado River Corridor, Grand Canyon, Arizona, 2013Data
These data are classification maps of total riparian vegetation along the Colorado River in Grand Canyon from Glen Canyon Dam to Pearce Ferry in Arizona. The data are derived from interpretation of multispectral high resolution airborne imagery that was acquired in May 2013. The total vegetation data have the same 0.2-meter ground resolution as the imagery. These data have not undergone a statistiFour Band Multispectral High Resolution Image Mosaic of the Colorado River Corridor, Arizona - 2013
In May 2013, the Grand Canyon Monitoring and Research Center (GCMRC) of the U.S. Geological Surveys (USGS) Southwest Biological Science Center (SBSC) acquired airborne multispectral high resolution data for the Colorado River in Grand Canyon in Arizona, USA. The imagery data consist of four bands (blue, green, red and near infrared) with a ground resolution of 20 centimeters (cm). These data are aGeomorphic Process from Topographic FormData & Models
The repeat topographic datasets used here are digital surface models (DSMs) derived using automated photogrammetry from photographs captured via aerial overflights during May 2002, 2009, and 2013. During overflights, discharge from Glen Canyon dam was held steady at 226 m3/s, and all subsequent analyses presented here apply to stages above this constant low flow discharge. DSMs are unique from tra - Multimedia
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Filter Total Items: 71
Can we accurately estimate sediment budgets on Mars?
Sediment budgets are fundamentally important for planetary science. However, only one primary method, based on remote sensing, is currently available for determining extraterrestrial sediment budgets. For determining sediment budgets on Earth, both in-situ and remote sensing methods are available. Despite the widespread use of the two methods, there has been surprisingly little research on how welAuthorsJoel B. Sankey, Alan Kasprak, Matthew Chojnacki, Timothy N. Titus, Joshua Caster, Geoffrey DeBenedettoParks look for ways to alleviate Glen Canyon Dam’s dramatic downstream impacts
Introduction Regardless of the location, time of day, or season, the grandeur of Grand Canyon National Park and Glen Canyon National Recreation Area inspires awe. Visitors can reflect on the sunlit colors of the towering canyon walls or witness the vibrant, golden display of Fremont cottonwood leaves each fall. For millions of years, the Colorado River has sculpted canyon country; for thousands ofAuthorsLonnie Pilkington, Joel B. Sankey, Dan Boughter, Taryn Preston, Cam C. ProphetWoody plant encroachment of grassland and the reversibility of shrub dominance: Erosion, fire, and feedback processes
Many grass-dominated ecosystems in dryland regions have experienced increasing woody plant density and abundance during the past century. In many cases, this process has led to land degradation and declines in ecosystem functions. An example is the Chihuahuan Desert in the southwestern United States, which experienced different stages of shrub encroachment in the past 150 years. Among a wide varieAuthorsJunran Li, Sujith Ravi, Guan Wang, R. Scott Van Pelt, Thomas E. Gill, Joel B. SankeyCarbon and ecohydrological priorities in managing woody encroachment: UAV perspective 63 years after a control treatment
Woody encroachment, including both woody species expansion and density increase, is a globally observed phenomenon that deteriorates arid and semi-arid rangeland health, biodiversity, and ecosystem services. Mechanical and chemical control treatments are commonly performed to reduce woody cover and restore ecohydrologic function. While the immediate impacts of woody control treatments are well docAuthorsTemuulen T. Sankey, Jackson Leonard, Margaret Moore, Joel B. Sankey, Adam BelmonteIntegrating airborne and mobile lidar data with UAV photogrammetry for rapid assessment of changing forest snow depth and cover
Forest structure and topography can influence the ecohydrologic function and resiliency to drought and changing climate. It is, therefore, important to understand how forest restoration treatments alter snowpack distribution and design the treatments accordingly. We use a combination of aerial lidar, multi-temporal terrestrial mobile lidar, and UAV photogrammetry to estimate rapidly changing snowAuthorsJonathon Donager, Temuulen Sankey, Andrew Sanchez-Meador, Joel B. Sankey, Abraham E. SpringerHydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon
A common impact on riparian ecosystem function following river regulation is the expansion and encroachment of riparian plant species in the active river channels and floodplain, which reduces flow of water and suspended sediment between the river, riparian area, and upland ecosystems. We characterized riparian plant species occurrence and quantified encroachment within the dam-regulated ColoradoAuthorsLaura E. Durning, Joel B. Sankey, Charles Yackulic, Paul Grams, Bradley J. Butterfield, Temuulen T. SankeyBiocrust and the soil surface: Influence of climate, disturbance, and biocrust recovery on soil surface roughness
Biocrust communities promote soil surface roughness, a key functional characteristic for soil ecology. However, the spatial scales at which biocrust communities contribute to surface roughness are not well understood. To refine our understanding of the spatial dynamics between biocrust and soil surface roughness, we used mm-resolution terrestrial LiDAR to measure micro-topographic roughness at sevAuthorsJoshua Caster, Temuulen T. Sankey, Joel B. Sankey, Matthew A. Bowker, Daniel Buscombe, Michael C. Duniway, Nichole Barger, Akasha M. Faist, Taylor JoyalPlanetary defense preparedness: Identifying the potential for post-asteroid impact time delayed and geographically displaced hazards
A considerable amount of effort has been done to quantify impact effects from the impact of an asteroid. The effects usually considered are: blast, overpressure shock, thermal radiation, cratering, seismic shaking, ejecta, and tsunami (e.g. Hills & Goda, 1993; Collins et al., 2005, Rumpf et al., 2017). These first-order effects typically are localized in time and diminish with increased distanceAuthorsTimothy N. Titus, D. G. Robertson, Joel B. SankeyAsteroid impacts - downwind and downstream effects
For this abstract, we have selected an impact location, consistent with the PDC2021 initial scenario [1], in the San Juan Mountains, in southwestern Colorado. This is a low-density population area but is part of the watershed system within the Colorado River basin, a major source for water and power for the southwestern United States. Several large cities and major airports are potentially downwinAuthorsTimothy N. Titus, D. G. Robertson, Joel B. Sankey, Larry G. MastinPreliminary assessment of carbon and nitrogen sequestration potential of wildfire-derived sediments stored by erosion control structures in forest ecosystems, southwest USA
The role of pyrogenic carbon (PyC) in the global carbon cycle is still incompletely characterized. Much work has been done to characterize PyC on landforms and in soils where it originates or in “terminal” reservoirs such as marine sediments. Less is known about intermediate reservoirs such as streams and rivers, and few studies have characterized hillslope and in-stream erosion control structuresAuthorsJames B. Callegary, Laura M. Norman, Christopher J. Eastoe, Joel B. Sankey, Ann YoubergMonitoring Tamarix changes using WorldView-2 satellite imagery in Grand Canyon National Park, Arizona
Remote sensing methods are commonly used to monitor the invasive riparian shrub tamarisk (Tamarix spp.) and its response to the northern tamarisk beetle (D. carinulata), a specialized herbivore introduced as a biocontrol agent to control tamarisk in the Southwest USA in 2001. We use a Spectral Angle Mapper (SAM) supervised classification method with WorldView-2 (2 m spatial resolution) multispectrAuthorsNathaniel D. Bransky, Temuulen T. Sankey, Joel B. Sankey, Matthew D. Johnson, Levi R. JamisonFuture regulated flows of the Colorado River in Grand Canyon foretell decreased areal extent of sediment and increases in riparian vegetation
Sediment transfer, or connectivity, by aeolian processes between channel-proximal and upland deposits in river valleys is important for the maintenance of river corridor biophysical characteristics. In regulated river systems, dams control the magnitude and duration of discharge. Alterations to the flow regime driven by dams that increase the inundation duration of sediment, or which drive the encAuthorsAlan Kasprak, Joel B. Sankey, Bradley J. Butterfield - News