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Sediment Dynamics in Dryland Rivers - Relations to Climate, Groundwater, and Land Use

In the southwest, as elsewhere, flooding, erosion, and sediment discharge are responsible for loss of life, land, and infrastructure, along with damage to reservoirs and natural habitats. The cutting (erosion) and in-filling (alluviation) of stream channels in the southwest are repeating processes that have occurred many times over the past several thousand years. The causes of the natural cycles of erosion and alluviation are not fully understood, and little is known about the interactions of natural alluvial conditions and human activities. Better understanding of these interactions and of climatic influences on flood frequency can lead communities and land managers to better planning and preparation for the future.

Most of the population in the desert Southwest is located on or adjacent to the floodplains of ephemeral streams or perennially flowing rivers. The behavior of these streams and rivers affects water supply and controls hazards such as flooding, debris flows, and bank erosion, all of which can have significant economic impact on desert Southwestern communities. In most of these investigations, we seek to recognize and understand changes in stream behavior and water table fluctuations related to short-term climate fluctuations and to land-use responses. Some activities address questions about landscape evolution during the Quaternary, such as development of the Grand Canyon, while another focuses on the interactions of stream sediment, groundwater, and dry lake floors that may set up conditions for dust emission.

For more information, select from the following topics:

• Recent flooding and environmental change in Las Vegas Wash
• Southern Colorado Plateau alluvial history, processes, and monitoring
• Rio Puerco Arroyo processes and climate
• Late Pleistocene and Holocene history of the southwestern Colorado Plateau
• Hazards and flood history in the San Miguel River valley, Colorado