River Ecosystems and Lake Powell

The U.S. Geological Survey Southwest Biological Science Center (SBSC) is uniquely positioned to provide sound information, specialized expertise, and innovative tools to support the management and sustained use of natural resources on public and Tribal lands in the Southwest U.S.

Riparian plant communities, associated with rivers and streams, are ecologically and culturally important areas in the southwestern U.S. Despite covering less than 2% of the land area in the southwest, the resources provided by these communities make them valuable to wildlife, the public, scientists, and resource managers.

A study conducted by the USGS provides new insights into the migration patterns of three native fish species in the Colorado River: humpback chub, flannelmouth sucker, and bluehead sucker. This research highlights the importance of understanding native fish population dynamics within the Colorado River ecosystem in Grand Canyon, AZ.

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...

The Grand Canyon Monitoring and Research Center, a branch of the Southwest Biological Science Center, conducts scientific assessments of the Colorado River in Grand Canyon, focused primarily on Lake Powell and the river ecosystem downstream of Glen Canyon Dam. On this page, we'd like to share related interactive tools and projects by other USGS Centers that cover science across the upper and lower...

In the Upper Colorado River Basin, smallmouth bass ( Micropterus dolomieu) are considered the greatest threat to native fishes and have been linked to declines in federally protected humpback chub ( Gila cypha), including one population that was rapidly extirpated in the past. Long-term management efforts have been underway to remove smallmouth bass from rivers in the Upper Basin, but smallmouth...

Threatened humpback chub are a native fish found only in the Colorado River Basin. Once found in warm-water canyons in the Basin, the largest population now persists in the Colorado River in Grand Canyon National Park, downstream of Glen Canyon Dam and Lake Powell, the reservoir upstream, created by the dam.

The Rio Grande/Rio Bravo (hereafter referred to as the Rio Grande) in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, has substantially narrowed since the early 1900s. This narrowing has been caused by the construction and operation of dams and irrigation diversions in upstream reaches of the Rio Grande in the U.S. and the Rio Conchos in Mexico that has reduced flows without...

River channels and their adjacent floodplains are ever evolving in form and composition in response to changing patterns of streamflow, the quantity and size of supplied sediment, and feedbacks with the riparian and aquatic ecosystems. Changes in channel form affect aquatic and riparian habitats, which are important for plants, animals, and insects. Erosion and deposition of river channels and...

Partners in Science is a collaborative effort between Grand Canyon Monitoring and Research Center, Grand Canyon Youth, and the National Park Service to provide opportunities for youth to engage in scientific field research in Grand Canyon. This partnership connects youth from diverse backgrounds with the Nation’s natural and cultural resources on 2-3 river-based expeditions on the Colorado River...

The Southwest Biological Science Center (SBSC) conducts and provides scientific information as part of our mission and Federal Trust Responsibility to strengthen relationships and build partnerships with sovereign tribal nations. Here, we highlight a few examples of projects with tribal partners.

USGS Southwest Biological Science Center's Grand Canyon Monitoring and Research Center provided scientific expertise to evaluate potential effects of reservoir management on various resources in Lake Powell and Grand Canyon. This information, published in a cooperator report, was requested and used by the Bureau of Reclamation for decision-making on water flows from Glen Canyon Dam.