Publications

The Middle Rio Grande (MRG) is a dynamic and complex fluvial system where flow and sediment transported from the Upper Rio Grande and MRG tributaries influence the form of the river. How sediment is transported through the MRG is an important planning question as it addresses a wide range of concerns including flood control and river rehabilitation, thus continuous sediment measurements...

The archaeological record documenting human history in deserts is commonly concentrated along rivers in terraces or other landforms built by river sediment deposits. Today that record is at risk in many river valleys owing to human resource and infrastructure development activities, including the construction and operation of dams. We assessed the effects of the operations of Glen Canyon...

The Colorado River is often referred to as “the lifeblood of the west.” The basin supplies municipal water to nearly 40 million people and irrigates approximately 22,000 km2 of agricultural lands. Twenty-two major rivers converge with the Colorado after it begins its descent from the Rocky Mountains and winds through the plateaus of Colorado, Utah, and Arizona, onto the deserts of...

Water availability is a result of complex interactions between regional water supply and demand and underlying environmental, institutional, and economic determinants. For this study, water availability is defined as “access to a specific quantity and quality of water at a point in time and space, for a specific use, recognizing the social and economic value of water across uses and...

Colorado Pikeminnow Ptychocheilus lucius, the Colorado River’s top native predatory fish, was historically distributed from the Gulf of California delta to the upper reaches of the Green, Colorado, and San Juan rivers in the Colorado River basin in the Southwestern US. In recent decades Colorado Pikeminnow population abundance has declined, primarily due to predation by warmwater...

Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we synthesize existing estimates of GHG emissions from streams, rivers, lakes and reservoirs, and homogenize them with regard to...

Inland waters are important sources of the greenhouse gasses (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) to the atmosphere. In the framework of the 2nd phase of the REgional Carbon Cycle Assessment and Processes (RECCAP-2) initiative, we review the state of the art in estimating inland water GHG budgets at global scale, which has substantially advanced since the...

The U.S. Geological Survey Community for Data Integration annually supports small projects focusing on data integration for interdisciplinary research, innovative data management, and demonstration of new technologies. This report provides a summary of the 14 projects supported in fiscal year 2019 and outlines their goals, activities, and accomplishments. Proposals in 2019 were...

Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian...

Recent drought has resulted in dramatic lowering of the two largest water-storage reservoirs in the western United States: Lake Powell and Lake Mead. These decreases in reservoir elevations have resulted in the re-emergence of over 100 km of the Colorado and San Juan rivers at the upstream end of Lake Powell and over 80 km of the Colorado River at the upstream end of Lake Mead. Upon...

The Colorado River ecosystem has experienced habitat alterations and non-native species invasions, and as a result, many of its native species have experienced extirpations, abundance declines, and range constrictions. Despite these pitfalls, Humpback Chub, Gila cypha, have persisted and, in the last 10-15 years, expanded their range to become abundant in western Grand Canyon, a river...

Changes in riparian vegetation cover and composition occur in relation to flow regime, geomorphic template, and climate, and can have cascading effects on aquatic and terrestrial ecosystems. Tracking such changes over time is therefore an important part of monitoring the condition and trajectory of riparian ecosystems. Maintaining diverse, self-sustaining riparian vegetation comprised of...