Flow of water and sediments through Southwestern riparian systems

Abstract

The paper describes streamflow, sediment movement and vegetation interactions within riparian systems of the southwestern United States. Riparian systems are found in a wide range of vegetation types, ranging from lower elevation desert environments to high elevation conifer forests. The climatic, vegetative and hydrologic processes operating in the southwestern environments provide a unique setting for discussing riparian ecosystem interactions with both water and sediment. Most streamflow at lower elevations is intermittent, and riparian vegetation frequently occupies channels that are dry at least part of the year. As a result, water table fluctuations in relation to streamflow and their subsequent effects on the establishment and maintenance of healthy riparian vegetation are key processes. At higher elevations, streamflow from snowmelt and rainfall is sufficient to sustain perennial streamflow and thereby provides a more consistent source of water for riparian vegetation. At all elevations, precipitation fluctuates widely, with many high-intensity, localized, convection storms occurring during the summer. As a result of this highly variable precipitation-runoff regime, erosion in the southwestern United States is an unsteady or discontinuous process that transports sediment from source areas through a channel system with Intermittent periods of storage. This episodic transport process is characteristic of drylands in the southwestern United States where big storms are the prime movers of sediment. Intermittent streamflow coupled with the discontinuous storage and subsequent movement of sediment through channel systems in response to fire and other disturbances is extremely complex, and can be difficult to interpret when assessing responses of southwestern riparian systems to management.

Parent Publication

• Desired future conditions for Southwestern riparian ecosystems: Bringing interests and concerns together

Citation

DeBano, Leonard F.; Ffolliott, Peter F.; Brooks, Kenneth N. 1996. Flow of water and sediments through Southwestern riparian systems. In: Shaw, Douglas W.; Finch, Deborah M., tech coords. Desired future conditions for Southwestern riparian ecosystems: Bringing interests and concerns together. 1995 Sept. 18-22, 1995; Albuquerque, NM. General Technical Report RM-GTR-272. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. p. 128-134.