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ARS Home » Pacific West Area » Tucson, Arizona » SWRC » Research » Publications at this Location » Publication #79860

Title: PROCESSES CONTROLLING SEDIMENT YIELD FROM WATERSHEDS AS FUNCTIONS OF SPATIAL SCALE

Author
item Lane, Leonard
item HERNANDEZ, M. - UNIV. OF ARIZ.

Submitted to: Journal of Environmental Modeling and Software
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sediment is a major pollutant, a transporter of pollutants, and sedimentation rates and amounts determine the performance and life of reservoirs, canals, drainage channels, harbors, and other downstream structures and improvements. Estimates of sediment yield are necessary to conduct water resources analyses and modeling, as well as to aid in engineering design. The sediment yield from a watershed is a measure of s erosion, transport, and deposition, and reflects the characteristics of a watershed, its history, development, use, and management. The major factors and processes controlling sediment yield from watersheds are described and discussed at plot, hillsope, subwatershed, and watershed scales. Historical sediment yield data from selected watersheds across a range of scales are u to illustrate variations of sediment yield with watershed scale. Watershed area is shown to be an important predictor variable which usually, but not always, is correlated with sediment yield. A case study is presented to illustrate processes controlling sediment yield. The case study summarizes and interprets simulation model studies using experimental field data from measurements distributed across a range of scales. Information presented h should help guide the conceptual development of sediment yield models and their mathematical formulation. It should also be useful in design and implementation of spatially distributed verification & validation studies.

Technical Abstract: The need for estimates of sediment yield are ubiquitous throughout water resources analyses, modeling, and engineering as sediment is a major pollutant, a transporter of pollutants, and sedimentation rates and amounts determine the performance and life of reservoirs, canals, drainage channels harbors, and other downstream structures and improvements. As a "watershed dwide" measure of soil erosion, transport, and deposition, sediment yield reflects the characteristics of a watershed, its history, development, use, and management. The major factors and processes controlling watershed sedim yield are described and discussed in the context of spatial scale. Historic sediment yield data from selected watersheds across a range of scales are u to illustrate variations of sediment yield with watershed scale. Generalize relationships between sediment yield and drainage area from the USA and Australia are used to show the statistical variations of sediment yield wit twatershed area. Area is shown to be an important predictor variable which usually, but not always, is correlated with sediment yield. A case study is presented to illustrate processes controlling sediment yield and to summari and interpret simulation model studies conducted across a range of scales. Information presented here should help guide the conceptual development of sediment yield models and their mathematical formulation, as well as the design and implementation of spatially distributed validation studies.