Grand Canyon Monitoring and Research Center

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Welcome to the Grand Canyon Monitoring and Research Center

The U.S. Geological Survey's Grand Canyon Monitoring and Research Center (GCMRC) is the science provider for the Glen Canyon Dam Adaptive Management Program. In this role, the research center provides the public and decision makers with relevant scientific information about the status and trends of natural, cultural, and recreational resources found in those portions of Grand Canyon National Park and Glen Canyon National Recreation Area affected by Glen Canyon Dam operations.


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Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon External Window Icon
Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled flo...
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Summary Report of Responses of Key Resources to the 2000 Low Steady Summer Flow Experiment, along the Colorado River Downstream from Glen Canyon Dam, Arizona External Window Icon
In the spring and summer of 2000, a series of steady discharges of water from Glen Canyon Dam on the Colorado River were used to evaluate the effects of aquatic habitat stability and water temperatures on native fish growth and survival, with a special focus on the endangered humpback chub (Gila cyp...
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An experiment to control nonnative fish in the Colorado River, Grand Canyon, Arizona: U.S. Geological Survey Fact Sheet 2011-3093 External Window Icon
The humpback chub (Gila cypha) is an endangered native fish found only in the Colorado River Basin. In Grand Canyon, most humpback chub are found in the Little Colorado River and its confluence with the Colorado River. For decades, however, nonnative rainbow trout (Oncorhynchus mykiss) and brown tro...
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Flow structures and sandbar dynamics in a canyon river during a controlled flood, Colorado River, Arizona External Window Icon
In canyon rivers, debris fan constrictions create rapids and downstream pools characterized by secondary flow structures that are closely linked to channel morphology. In this paper we describe detailed measurements of the three-dimensional flow structure and sandbar dynamics of two pools along the ...
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Mechanics and modeling of flow sediment transport and morphologic change in riverine lateral separation zones, in Hydrology and sedimentation for a changing future External Window Icon
Lateral separation zones or eddies in rivers are critically important features for sediment storage and for a variety of roles they play in riparian and aquatic ecology. As part of a larger effort to predict the morphology of lateral separation zones in the Colorado River in Grand Canyon for a selec...
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Sandbar response in Marble and Grand Canyons, Arizona, following the 2008 high-flow experiment on the Colorado River External Window Icon
A 60-hour release of water at 1,203 cubic meters per second (m3/s) from Glen Canyon Dam in March 2008 provided an opportunity to analyze channel-margin response at discharge levels above the normal, diurnally fluctuating releases for hydropower plant operations. We compare measurements at sandbars a...
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20,000 grain-size observations from the bed of the Colorado River and implications for sediment transport through Grand Canyon, in Hydrology and sedimentation for a changing future; existing and emerging issues  External Window Icon
In the late 1990s, we developed digital imaging hardware and software for in-situ mapping of sand-sized bed sediment of the Colorado River in Grand Canyon. This new technology enables collection and processing of hundreds of grain-size samples in a day. Bed grain size was mapped using this equipment...
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Grain-size evolution in suspended sediment and deposits from the 2004 and 2008 controlled-flood experiments in the Marble and Grand Canyons, Arizona, in Hydrology and sedimentation for a changing future; existing and emerging issues External Window Icon
Since the closure of Glen Canyon Dam in 1963, the hydrology, sediment supply, and distribution and size of modern alluvial deposits in the Colorado River through Grand Canyon have changed substantially (e.g., Howard and Dolan, 1981; Johnson and Carothers, 1987; Webb et al., 1999; Rubin et al., 2002...
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2008 Weather and aeolian sand-transport data from the Colorado River corridor, Grand Canyon, Arizona External Window Icon
Since the closure of Glen Canyon Dam in 1963, the hydrology, sediment supply, and distribution and size of modern alluvial deposits in the Colorado River through Grand Canyon have changed substantially (e.g., Howard and Dolan, 1981; Johnson and Carothers, 1987; Webb et al., 1999; Rubin et al., 2002;...
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2008 high-flow experiment at Glen Canyon Dam—morphologic response of eddy-deposited sandbars and associated aquatic backwater habitats along the Colorado River in Grand Canyon National Park External Window Icon
The March 2008 high-flow experiment (HFE) at Glen Canyon Dam resulted in sandbar deposition and sandbar reshaping such that the area and volume of associated backwater aquatic habitat in Grand Canyon National Park was greater following the HFE. Analysis of backwater habitat area and volume for 116 l...
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Effects of fluctuation flows and a controlled flood on incubation success and early survival rates and growth of age-0 rainbow trout in a large regulated river External Window Icon
Hourly fluctuations in flow from Glen Canyon Dam were increased in an attempt to limit the population of nonnative rainbow trout Oncorhynchus mykiss in the Colorado River, Arizona, due to concerns about negative effects of nonnative trout on endangered native fishes. Controlled floods have also be...
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Kanab Ambersnail habitat mitigation for the 2008 high flow experiment—August 2009 draft cooperator report from Arizona Game and Fish Department External Window Icon
Long-term fish monitoring in the Colorado River below Glen Canyon Dam is an essential component of the Glen Canyon Dam Adaptive Management Program (GCDAMP). The GCDAMP is a federally authorized initiative to ensure that the primary mandate of the Grand Canyon Protection Act of 1992 to protect resour...
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Status and Trends of the Rainbow Trout Population in the Lees Ferry Reach of the Colorado River downstream from Glen Canyon Dam, Arizona, 1991–2009 External Window Icon
The Lees Ferry reach of the Colorado River, a 25-kilometer segment of river located immediately downstream from Glen Canyon Dam, has contained a nonnative rainbow trout (Oncorhynchus mykiss) sport fishery since it was first stocked in 1964. The fishery has evolved over time in response to changes in...
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Abiotic & Biotic Responses of the Colorado River to Controlled Flood Experiments at Glen Canyon Dam, Arizona, USA External Window Icon
Closure of Glen Canyon Dam reduced sand supply to the Colorado River in Grand Canyon National Park by about 94% while its operation has also eroded the park's sandbar habitats. Three controlled floods released from the dam since 1995 suggest that sandbars might be rebuilt and maintained, but only if...
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Three Experimental High-Flow Releases from Glen Canyon am, Arizona—Effects on the Downstream Colorado River Ecosystem External Window Icon
Three high-flow experiments (HFEs) were conducted by the U.S. Department of the Interior at Glen Canyon Dam, Arizona, in March 1996, November 2004, and March 2008. Also known as artificial or controlled floods, these scheduled releases of water above the dam’s powerplant capacity were designed to mi...
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Status and Trends of the Rainbow Trout Population in the Lees Ferry Reach of the Colorado River downstream from Glen Canyon Dam, Arizona, 1991-2009 External Window Icon
The Lees Ferry reach of the Colorado River, a 25-kilometer segment of river located immediately downstream from Glen Canyon Dam, has contained a nonnative rainbow trout (Oncorhynchus mykiss) sport fishery since it was first stocked in 1964. The fishery has evolved over time in response to changes in...
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Trout piscivory on the Colorado River, Grand Canyon: Effects of turbidity, temperature, and fish prey availability External Window Icon
Introductions of nonnative salmonids, such as rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta, have affected native fishes worldwide in unforeseen and undesirable ways. Predation and other interactions with nonnative rainbow trout and brown trout have been hypothesized as contributing...

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Grand Canyon Monitoring & Research Center | 2255 North Gemini Drive Flagstaff, AZ 86001 | Phone: 928.556.7380 Fax: 928.556.7100

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Last Update: November 3, 2011