Chris Holmquist-Johnson, PhD, PE
Chris Holmquist-Johnson is a Hydrologist and UAS Pilot with the USGS Fort Collins Science Center’s Ecosystem and Organismal Ecology (EcOE) branch. His research focuses on studying the response of riverine and riparian species and habitats to flow alteration, drought, and dam management in support of conservation and restoration of community structure and function—especially for at-risk species.
Chris' research includes integrated riverine ecosystem studies, aquatic habitat assessment, in-stream flow modeling and decision support system development. In 2010 he obtained his remote pilot certification for Uncrewed Aircraft Systems (UAS) and is involved with numerous UAS operations within DOI and USGS related to terrestrial wildlife, hydrologic mapping, habitat mapping/analysis, river system processes, and emergency response utilizing natural color, multi-spectral, thermal, and LiDAR sensors. His work also includes collaborations with the USGS National Uncrewed Systems Office (NUSO) in supporting the integration of UAS data collection into the scientific, monitoring, and resource management functions of the Department of the Interior (DOI). Strategic implementation of UAS within the USGS focuses on the evaluation and integration of new innovative sensors, development of data standards and processing techniques, recommendations of UAS data acquisition best-practices, and support for the training and proficiency of new and existing UAS operators within USGS.
Professional Experience
2008–present, Hydrologist and UAS Pilot, USGS Fort Collins Science Center, Fort Collins, CO
2004-2008, Hydraulic Engineer, Bureau of Reclamation Erosion and Sedimentation Group, Denver, CO
2003-2004, Hydraulic Engineer, Tetra Tech Inc., Breckenridge, CO
Education and Certifications
Ph.D. in Civil and Environmental Engineering, Colorado State University, 2011
M.S. in Civil and Environmental Engineering, Colorado State University, 2002
B.S. in Civil Engineering, Colorado State University, 1999
Science and Products
Photogrammetric data collected by small unoccupied aircraft system for vegetation analysis at three study reaches along the Verde River, Arizona, December 2017 Photogrammetric data collected by small unoccupied aircraft system for vegetation analysis at three study reaches along the Verde River, Arizona, December 2017
The U.S. Geological Survey collected low-altitude airborne visual imagery via a multirotor, small unoccupied aircraft system (sUAS) along with Real Time Kinematic (RTK) GPS survey data at three study sites (Beasley Flat, Childs, and Sheep Bridge) along the Verde River in Arizona in December 2017. Visual imagery was collected in jpg format and Structure from Motion techniques were applied...
Orthoimagery and elevation data derived from UAS imagery for Palmyra Atoll, USA 2016 (ver. 1.1, November 2020) Orthoimagery and elevation data derived from UAS imagery for Palmyra Atoll, USA 2016 (ver. 1.1, November 2020)
Point clouds, high resolution digital surface models (DSM), and high resolution orthoimagery of Palmyra Atoll, USA, were generated from aerial 3-color and 5-band imagery collected October 2016 using Unoccupied Aerial Systems (UAS, or "drones"). Data were processed in sections corresponsing to flight areas using photogrammetry to generate three-dimensional point clouds (.las) by...
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, 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...
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 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
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...
An integrated Riverine Environmental Flow Decision Support System (REFDSS) to evaluate the ecological effects of alternative flow scenarios on river ecosystems An integrated Riverine Environmental Flow Decision Support System (REFDSS) to evaluate the ecological effects of alternative flow scenarios on river ecosystems
In regulated rivers, managers must evaluate competing flow release scenarios that attempt to balance both human and natural needs. Meeting these natural flow needs is complex due to the myriad of interacting physical and hydrological factors that affect ecosystems. Tools that synthesize the voluminous scientific data and models on these factors will facilitate management of these systems...
Authors
Kelly O. Maloney, Colin B. Talbert, Jeffrey C. Cole, Heather S. Galbraith, Carrie J. Blakeslee, Leanne Hanson, Christopher L. Holmquist-Johnson
Evaluation of the Raven sUAS to detect and monitor greater sage-grouse leks within the Middle Park population Evaluation of the Raven sUAS to detect and monitor greater sage-grouse leks within the Middle Park population
Staff from the U.S. Geological Survey Fort Collins Science Center and the Colorado Parks and Wildlife Hot Sulphur Springs Office began discussions in 2011 for a proof of concept study to test the Raven RQ-11A small Unmanned Aircraft System (Raven sUAS) for its suitability to detect and monitor greater sage-grouse (Centrocercus urophasianus) breeding sites (leks). During April 2013, the...
Authors
Leanne Hanson, Christopher L. Holmquist-Johnson, Michelle L. Cowardin
User's manual for the upper Delaware River riverine environmental flow decision support system (REFDSS), Version 1.1.2 User's manual for the upper Delaware River riverine environmental flow decision support system (REFDSS), Version 1.1.2
Between 2002 and 2006, the Fort Collins Science Center (FORT) at the U.S. Geological Survey (USGS) conducted field surveys, organized workshops, and performed analysis of habitat for trout and shad in the Upper Delaware River Basin. This work culminated in the development of decision support system software (the Delaware River DSS–DRDSS, Bovee and others, 2007) that works in conjunction...
Authors
Colin Talbert, Kelly O. Maloney, Chris Holmquist-Johnson, Leanne Hanson
Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California
The Klamath River is a major river in northern California and southern Oregon. Iron Gate Dam divides the river into the two subunits where there is a significant change in utilization of the river. Downstream of Iron Gate Dam, the river is very important for the propagation of salmon. To address concerns relating to substrate conditions in the mainstem Klamath River below Iron Gate Dam...
Authors
Cristopher L. Holmquist-Johnson, Robert T. Milhous
Relation between Streamflow of Swiftcurrent Creek, Montana, and the Geometry of Passage for Bull Trout (Salvelinus confluentus) Relation between Streamflow of Swiftcurrent Creek, Montana, and the Geometry of Passage for Bull Trout (Salvelinus confluentus)
Operation of Sherburne Dam in northcentral Montana has typically reduced winter streamflow in Swiftcurrent Creek downstream of the dam and resulted in passage limitations for bull trout (Salvelinus confluentus). We defined an empirical relation between discharge in Swiftcurrent Creek between Sherburne Dam and the downstream confluence with Boulder Creek and fish passage geometry by...
Authors
Gregor T. Auble, Christopher L. Holmquist-Johnson, Jim T. Mogen, Lynn R. Kaeding, Zachary H. Bowen
Qualitative evaluation of rock weir field performance and failure mechanisms Qualitative evaluation of rock weir field performance and failure mechanisms
River spanning loose-rock structures provide sufficient head for irrigation diversion, permit fish passage over barriers, protect banks, stabilize degrading channels, activate side channels, reconnect floodplains, and create in-channel habitat. These structures are called by a variety of names including rock weirs, alphabet (U-, A-, V-, W-) weirs, Jhooks, and rock ramps. These structures...
Authors
David M. Mooney, Christopher L. Holmquist-Johnson, Elaina Holburn
Non-USGS Publications**
Holmquist-Johnson, C., D. Raff, and K. Russell. 2009. Bureau of Reclamation Automated Modified Einstein Procedure (BORAMEP) Program for Computing Total Sediment Discharge. Sedimentation and River Hydraulics Group. Denver, CO: Bureau of Reclamation, U.S. Department of the Interior. 48 p.
Holmquist-Johnson, C.L. and D. Raff. 2006. Bureau of Reclamation Automated Modified Einstein Procedure (BORAMEP) Program for Computing Total Sediment Load. Federal Interagency Sedimentation Conference in Reno, NV., April 2-6, 2006. Federal Interagency Sedimentation Project . p. 8.
Holmquist-Johnson, C. 2004. Sediment Model for the Middle Rio Grande – Phase 1, San Acacia Diversion Dam to Elephant Butte Reservoir. Sedimentation and River Hydraulics Group. Denver, CO: U.S. Department of the Interior, Bureau of Reclamation. 91 p.
Holmquist-Johnson, C.L. 2002. Computational methods for determining effective discharge in the Yazoo River Basin, Mississippi Fort Collins, CO: Colorado State University. 146 p.
Watson, C.C., D.P. Roseboom, C.L. Holmquist-Johnson, and M.D. Robeson. 2002. Development of design criteria for siting and spacing of grade control structures, Phase I. Preliminary Report. Fort Collins, CO: Engineering Research Center, Colorado State University. 34 p.
Watson, C.C., B.P. Bledsoe, C.L. Holmquist-Johnson, D.M. Mooney, and A.M. Haas. 1999. Demonstration erosion control monitoring sites: 1999 evaluation. Submitted to: Commander, U.S. Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi 39180. Fort Collins, CO: Department of Civil Engineering, Colorado State University. 245 p.
Holmquist-Johnson, C.L., C.I. Thornton, C.C. Watson, and S.R. Abt. 1999. Laboratory Testing of A-Jacks Units for Inland Applications - Hydraulic Property Documentation. Report submitted to Armortec Concrete Erosion Control Systems. Fort Collins, CO: Department of Civil Engineering, Colorado State University. various p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Photogrammetric data collected by small unoccupied aircraft system for vegetation analysis at three study reaches along the Verde River, Arizona, December 2017 Photogrammetric data collected by small unoccupied aircraft system for vegetation analysis at three study reaches along the Verde River, Arizona, December 2017
The U.S. Geological Survey collected low-altitude airborne visual imagery via a multirotor, small unoccupied aircraft system (sUAS) along with Real Time Kinematic (RTK) GPS survey data at three study sites (Beasley Flat, Childs, and Sheep Bridge) along the Verde River in Arizona in December 2017. Visual imagery was collected in jpg format and Structure from Motion techniques were applied...
Orthoimagery and elevation data derived from UAS imagery for Palmyra Atoll, USA 2016 (ver. 1.1, November 2020) Orthoimagery and elevation data derived from UAS imagery for Palmyra Atoll, USA 2016 (ver. 1.1, November 2020)
Point clouds, high resolution digital surface models (DSM), and high resolution orthoimagery of Palmyra Atoll, USA, were generated from aerial 3-color and 5-band imagery collected October 2016 using Unoccupied Aerial Systems (UAS, or "drones"). Data were processed in sections corresponsing to flight areas using photogrammetry to generate three-dimensional point clouds (.las) by...
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, 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...
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 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
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...
An integrated Riverine Environmental Flow Decision Support System (REFDSS) to evaluate the ecological effects of alternative flow scenarios on river ecosystems An integrated Riverine Environmental Flow Decision Support System (REFDSS) to evaluate the ecological effects of alternative flow scenarios on river ecosystems
In regulated rivers, managers must evaluate competing flow release scenarios that attempt to balance both human and natural needs. Meeting these natural flow needs is complex due to the myriad of interacting physical and hydrological factors that affect ecosystems. Tools that synthesize the voluminous scientific data and models on these factors will facilitate management of these systems...
Authors
Kelly O. Maloney, Colin B. Talbert, Jeffrey C. Cole, Heather S. Galbraith, Carrie J. Blakeslee, Leanne Hanson, Christopher L. Holmquist-Johnson
Evaluation of the Raven sUAS to detect and monitor greater sage-grouse leks within the Middle Park population Evaluation of the Raven sUAS to detect and monitor greater sage-grouse leks within the Middle Park population
Staff from the U.S. Geological Survey Fort Collins Science Center and the Colorado Parks and Wildlife Hot Sulphur Springs Office began discussions in 2011 for a proof of concept study to test the Raven RQ-11A small Unmanned Aircraft System (Raven sUAS) for its suitability to detect and monitor greater sage-grouse (Centrocercus urophasianus) breeding sites (leks). During April 2013, the...
Authors
Leanne Hanson, Christopher L. Holmquist-Johnson, Michelle L. Cowardin
User's manual for the upper Delaware River riverine environmental flow decision support system (REFDSS), Version 1.1.2 User's manual for the upper Delaware River riverine environmental flow decision support system (REFDSS), Version 1.1.2
Between 2002 and 2006, the Fort Collins Science Center (FORT) at the U.S. Geological Survey (USGS) conducted field surveys, organized workshops, and performed analysis of habitat for trout and shad in the Upper Delaware River Basin. This work culminated in the development of decision support system software (the Delaware River DSS–DRDSS, Bovee and others, 2007) that works in conjunction...
Authors
Colin Talbert, Kelly O. Maloney, Chris Holmquist-Johnson, Leanne Hanson
Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California
The Klamath River is a major river in northern California and southern Oregon. Iron Gate Dam divides the river into the two subunits where there is a significant change in utilization of the river. Downstream of Iron Gate Dam, the river is very important for the propagation of salmon. To address concerns relating to substrate conditions in the mainstem Klamath River below Iron Gate Dam...
Authors
Cristopher L. Holmquist-Johnson, Robert T. Milhous
Relation between Streamflow of Swiftcurrent Creek, Montana, and the Geometry of Passage for Bull Trout (Salvelinus confluentus) Relation between Streamflow of Swiftcurrent Creek, Montana, and the Geometry of Passage for Bull Trout (Salvelinus confluentus)
Operation of Sherburne Dam in northcentral Montana has typically reduced winter streamflow in Swiftcurrent Creek downstream of the dam and resulted in passage limitations for bull trout (Salvelinus confluentus). We defined an empirical relation between discharge in Swiftcurrent Creek between Sherburne Dam and the downstream confluence with Boulder Creek and fish passage geometry by...
Authors
Gregor T. Auble, Christopher L. Holmquist-Johnson, Jim T. Mogen, Lynn R. Kaeding, Zachary H. Bowen
Qualitative evaluation of rock weir field performance and failure mechanisms Qualitative evaluation of rock weir field performance and failure mechanisms
River spanning loose-rock structures provide sufficient head for irrigation diversion, permit fish passage over barriers, protect banks, stabilize degrading channels, activate side channels, reconnect floodplains, and create in-channel habitat. These structures are called by a variety of names including rock weirs, alphabet (U-, A-, V-, W-) weirs, Jhooks, and rock ramps. These structures...
Authors
David M. Mooney, Christopher L. Holmquist-Johnson, Elaina Holburn
Non-USGS Publications**
Holmquist-Johnson, C., D. Raff, and K. Russell. 2009. Bureau of Reclamation Automated Modified Einstein Procedure (BORAMEP) Program for Computing Total Sediment Discharge. Sedimentation and River Hydraulics Group. Denver, CO: Bureau of Reclamation, U.S. Department of the Interior. 48 p.
Holmquist-Johnson, C.L. and D. Raff. 2006. Bureau of Reclamation Automated Modified Einstein Procedure (BORAMEP) Program for Computing Total Sediment Load. Federal Interagency Sedimentation Conference in Reno, NV., April 2-6, 2006. Federal Interagency Sedimentation Project . p. 8.
Holmquist-Johnson, C. 2004. Sediment Model for the Middle Rio Grande – Phase 1, San Acacia Diversion Dam to Elephant Butte Reservoir. Sedimentation and River Hydraulics Group. Denver, CO: U.S. Department of the Interior, Bureau of Reclamation. 91 p.
Holmquist-Johnson, C.L. 2002. Computational methods for determining effective discharge in the Yazoo River Basin, Mississippi Fort Collins, CO: Colorado State University. 146 p.
Watson, C.C., D.P. Roseboom, C.L. Holmquist-Johnson, and M.D. Robeson. 2002. Development of design criteria for siting and spacing of grade control structures, Phase I. Preliminary Report. Fort Collins, CO: Engineering Research Center, Colorado State University. 34 p.
Watson, C.C., B.P. Bledsoe, C.L. Holmquist-Johnson, D.M. Mooney, and A.M. Haas. 1999. Demonstration erosion control monitoring sites: 1999 evaluation. Submitted to: Commander, U.S. Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, Mississippi 39180. Fort Collins, CO: Department of Civil Engineering, Colorado State University. 245 p.
Holmquist-Johnson, C.L., C.I. Thornton, C.C. Watson, and S.R. Abt. 1999. Laboratory Testing of A-Jacks Units for Inland Applications - Hydraulic Property Documentation. Report submitted to Armortec Concrete Erosion Control Systems. Fort Collins, CO: Department of Civil Engineering, Colorado State University. various p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.