Southwest Biological Science Center

Grand Canyon Monitoring and Research Center

The US Geological Survey’s Grand Canyon Monitoring and Research Center (GCMRC) measures effects of Glen Canyon Dam operations on the resources along the Colorado River from Glen Canyon Dam, near Page, Arizona to the inflow of Lake Mead.

GCMRC Science Projects

GCMRC Science Projects

GCMRC science efforts focus on the effects of operations from Glen Canyon Dam on the physical, biological and ecological processes and resources of the Colorado River downstream of the dam.

GCMRC Projects

River Ecosystem Science

River Ecosystem Science

The River Ecosystem Science (RES) branch of SBSC performs science monitoring of riparian resources, including biology, ecology and physical processes, for many iconic rivers in the American West and through parnterships on rivers around the world.

As the science provider for the Glen Canyon Dam Adaptive Management Program (GCDAMP), 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.

Background and History

Approximately 15 river miles upstream of the Grand Canyon National Park boundary at Lees Ferry sits Glen Canyon Dam, completed in 1963. The dam provides hydroelectric power for 200 wholesale customers in six Western States, and it is an important component of the Nation’s western electrical grid system, but it has also altered the Colorado River’s flow, temperature, and sediment-carrying capacity. Over time the operation of Glen Canyon Dam has contributed to beach erosion, invasion and expansion of nonnative species, and losses of native fish, as well as other measureable effects.

Public concern about the effects of Glen Canyon Dam operations on the downstream environment in lower Glen Canyon and Grand Canyon National Park prompted passage of the Grand Canyon Protection Act of 1992 which directs the Secretary of the Interior to operate the dam "to protect, mitigate adverse impacts to, and improve values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established..." (Grand Canyon Protection Act of 1992, Bureau of Reclamation).

Following a 1996 Record of Decision on an Environmental Impact Study for Operations of Glen Canyon Dam, the dam has been operated with a modified low fluctuating flow (MLLF) regime.  The Record of Decision also allowed for experimental high flow releases, and other experimental flow regimes, to improve scientific understanding on how to operate the dam to minimize impacts to the environment and hydropower production while improving resource conditions downstream.  

This legislation also required the creation of a long-term monitoring and research program to provide information that could inform management policies and decisions related to dam operations and protection of downstream resources.  As the science provider to the Glen Canyon Dam Adaptive Management Program (GCDAMP), GCMRC designs and implements scientific studies to meet the objectives put forward by stakeholders and managers of the GCDAMP.

GCMRC also develops scientific information on other related factors that affect downstream resources, as well as non-flow measures to mitigate adverse impacts.  The GCMRC focuses its efforts on three primary activities: (1) monitoring status and trends in resource condition, (2) focused research on specific topics of concern to GCDAMP stakeholders and (3) experimentation.  The GCMRC works closely and cooperatively with a wide range of Federal, State, and Tribal resource management agencies; academic institutions; and private consultants.