Chris Holmquist-Johnson, Ph.D.
Science and Products
As the need for incorporating biological objectives into water management decisions has grown, so has the need for methods and metrics to incorporate predictions of relevant biological responses into an increasingly complex decision environment that attempts to balance multiple uses.
Small Unmanned Aircraft Systems (sUAS) are an emerging technology which may result in safer and improved methods to conduct wildlife surveys. The objective of this task is to test the capabilities of various cameras and sensors onboard a small Unoccupied (or unmanned) Aircraft System (sUAS) to determine if they are a useful and effective tool to inventory various flora and fauna important to USGS partners and collaborators.
Development of a decision support tool for water and resource management using biotic, abiotic, and hydrological assessments of Topock Marsh, Arizona
Topock Marsh is a large wetland adjacent to the Colorado River and the main feature of Havasu National Wildlife Refuge (Havasu NWR) in southern Arizona. In 2010, the U.S. Fish and Wildlife Service (FWS) and Bureau of Reclamation began a project to improve water management capabilities at Topock Marsh and protect habitats and species. Initial...Holmquist-Johnson, Christopher; Hanson, Leanne; Daniels, Joan; Talbert, Colin; Haegele, Jeanette
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)...Hanson, Leanne; Holmquist-Johnson, Christopher L.; Cowardin, Michelle L.
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...Talbert, Colin; Maloney, Kelly O.; Holmquist-Johnson, Chris; Hanson, Leanne
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...Holmquist-Johnson, Cristopher L.; Milhous, Robert T.
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...Auble, Gregor T.; Holmquist-Johnson, Christopher L.; Mogen, Jim T.; Kaeding, Lynn R.; Bowen, Zachary H.
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...Mooney, David M.; Holmquist-Johnson, Christopher L.; Holburn, Elaina
Rock ramp design guidelines
Rock ramps or roughened channels consist of steep reaches stabilized by large immobile material (riprap). Primary objectives for rock ramps include: Create adequate head for diversionMaintain fish passage during low-flow conditionsMaintain hydraulic conveyance during high-flow conditionsSecondary objectives for rock ramp design include:Emulate...Mooney, David M.; Holmquist-Johnson, Christopher L.; Broderick, Susan
The purpose of the Physical Habitat Simulation System (PHABSIM) is to simulate a relationship between streamflow and physical habitat for various life stages of a species of fish or a recreational activity.