Abstract
Sediment is one of the principal pollutants of surface waters of the United States. Efforts by the USDA to quantify and control sediment erosion have historically focused on fields and upland areas. There is a growing body of evidence in agricultural areas, however, that the locus of sediment erosion has shifted from fields and uplands to channels. This is a critical issue in the Conservation Effects Assessment Project that evaluates the effectiveness of controls on sediment erosion. Rapid geomorphic assessments indicate that channel contributions are significant sources of sediment in the studied watersheds. The relative importance of channel processes are obtained by comparing “reference” yields for the ecoregion with the respective watershed yields. Annual suspended sediment yields for the Conservation Effects Assessment Project watersheds exceed the median value for stable streams by 243% in Iowa, 290% in New York, 630% in Mississippi, and between 2,120% and 7,410% in Oklahoma. Erosion from streambanks is an important process that must be addressed in management strategies aimed at controlling sediment production and delivery.
Footnotes
Andrew Simon is a research geologist at the Watershed Physical Processes Research Unit, National Sedimentation Laboratory, USDA Agricultural Research Service, Oxford, Mississippi. Lauren Klimetz is a research associate in the School of Engineering, University of Mississippi, University, Mississippi.
- © 2008 by the Soil and Water Conservation Society
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.