Southwest Biological Science Center
Glen Canyon Dam Adaptive Management Program (GCDAMP)
The Grand Canyon Monitoring and Research Center (GCMRC) is the science provider for the Glen Canyon Dam Adaptive Management Program (GCDAMP), and its scientists study the effects of Glen Canyon Dam operations on the resources of Grand Canyon. More information about the GCDAMP can be found at the Bureau of Reclamation and the GCDAMP Wiki page. Neither of these sites are US Geological Survey (USGS) websites, so accessing those sites means you will leave the USGS website and will be entering other domains.
Bureau of Reclamation, GCDAMP Page
The Bureau of Reclamation's web page for the Glen Canyon Dam Adaptive Management Program contains a wealth of information on Glen Canyon Dam and the Adaptive Management Program (GCDAMP). This will take you to a site not maintained by the USGS.
BOR GCDAMPGCDAMP Wiki Pages
An unofficial, yet valuable resource for all things related to the adaptive management program, including how the adaptive management process works, recent meetings, and more. This site is not maintained by USGS or any other government entity.
GCDAMP WikiBrowse Glen Canyon Dam Adaptive Management Program (GCDAMP) science related to:
High-Flow Experiments on the Colorado River
Glen Canyon Dam has altered flow and fine sediment (sand, silt, and clay) dynamics of the Colorado River in Grand Canyon. Before the dam, the Colorado River experienced highly variable flows and carried a large amount of sediment through Grand Canyon, which maintained sandbars (highly valued camping areas in Grand Canyon) and provided sand that protected archeological and cultural sites from...
River Sediment Dynamics
Sediment controls the physical habitat of river ecosystems. Changes in the amount and areal distribution of different sediment types cause changes in river-channel form and river habitat. The amount and type of sediment suspended in the water column determines water clarity. Understanding sediment transport and the conditions under which sediment is deposited or eroded from the various...
Population Dynamics of Endangered Humpback Chub in Grand Canyon
Construction of Glen Canyon Dam has led to large changes in environmental conditions of the downriver Colorado River. Whereas the pre-dam Colorado River experienced large seasonal variation in temperature and discharge and was highly turbid, the post-dam Colorado River is far less variable in terms of temperature and discharge and is frequently clear. Many nonnative fish species had already...
Understanding Factors Influencing Rainbow Trout Growth in the Colorado River
Rainbow trout is a desirable sport fish that has been introduced in many locations around the world. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying management options that allow...
SBSC Scientist Directory
Click on "Science" to go to the SBSC scientist directory. When you click on a scientist's name (you may need to scroll down to see all the names), you will be taken to that scientist's professional page and contact information.
Connectivity of Sand Resources Along the Colorado River in Grand Canyon
We study the links among different geomorphic processes that affect river valley landscapes in the Colorado River downstream from Glen Canyon Dam, Arizona. Dam-released flows affect the deposition and retention of sandbars that serve as sources for other sand resources, such as windblown sand dunes, throughout the Colorado River ecosystem. The degree to which the landscapes are differentially...
Effects of Water Clarity on Survival of Endangered Humpback Chub
Introduced rainbow trout and brown trout are considered a threat to the endangered humpback chub in the Colorado River in Grand Canyon. These introduced species eat native fish, but impacts are difficult to assess because predation vulnerability depends on the physical conditions under which predation takes place. We studied how predation vulnerability of juvenile humpback chub changes in...
Riparian Remote Sensing in the Colorado River and Grand Canyon Region
Riparian vegetation has increased dramatically along the Colorado River downstream of Glen Canyon Dam since the closure of the dam in 1963. The spatial patterns and temporal rates of vegetation increase occur due to changes in river hydrology, dam operations, and climate. The increase in vegetation, particularly onto otherwise bare sandbars, has impacted recreational, geomorphological,...
Economics of Outdoor Recreation
Economic research at Grand Canyon Monitoring and Research Center is used to determine economic benefits of outdoor recreation in Glen Canyon National Recreation Area below Glen Canyon Dam and in Grand Canyon National Park, as affected by operation of Glen Canyon Dam. This research identifies recreationists’ preferences for attributes associated with their trips, spending that occurs regionally...
Insect Drift
All aquatic invertebrates drift downstream at some point in their life cycle. Invertebrates may drift to find more preferable habitats, to leave the water during their transition from aquatic larvae to terrestrial adults, or accidentally such as when swept off the river bed by a flood. Regardless, when they enter the drift, invertebrates become particularly susceptible to predation by several...
Grand Canyon Sandbar Monitoring
Since the completion of Glen Canyon Dam in 1963, the amount of sand supplied to Grand Canyon National Park has been reduced by more than 90 percent. The Paria River, a tributary to the Colorado River 15 miles downstream from the dam, is now the single most important supplier of sand to the Colorado River within the Park. This large reduction in sand supply has resulted in substantial decrease...
Adaptive Management
In 1996, the Secretary of the Interior signed a formal decision altering the historical flows from Glen Canyon Dam and establishing the Glen Canyon Dam Adaptive Management Program (GCDAMP). In the context of the management of Glen Canyon Dam, adaptive management was selected to create a process whereby “the effects of dam operations on downstream resources would be assessed and the results of...
Sediment Storage in the Colorado River
The sandbars exposed along the shoreline of the Colorado River represent only a small fraction of the sand deposits in Grand Canyon, most of which are on the bed of the river in eddies and the channel. Current management practice includes efforts to maintain and build sandbars by releasing high flows from Glen Canyon Dam that are timed to coincide with periods of fine-sediment supply from...