Ephemeral Gully Erosion – A Natural Resource Concern

Authors: BERNARD, JERRY - Natural Resources Conservation Service (NRCS, USDA); Bingner, Ronald - Ron; Dabney, Seth; Langendoen, Eddy; LEMUNYON, JERRY - Natural Resources Conservation Service (NRCS, USDA); MERKEL, WILLIAM - Natural Resources Conservation Service (NRCS, USDA); THEURER, FRED - Natural Resources Conservation Service (NRCS, USDA); Wells, Robert - Rob; WIDMAN, NORM - Natural Resources Conservation Service (NRCS, USDA); Wilson, Glenn

Submitted to: Laboratory Publication
Publication Type: Government Publication
Publication Acceptance Date: 1/22/2010
Publication Date: 2/23/2010
Citation: Bernard, J., Bingner, R.L., Dabney, S.M., Langendoen, E.J., Lemunyon, J., Merkel, W., Theurer, F., Wells, R.R., Widman, N., Wilson, G.V. 2010. Ephemeral Gully Erosion – A Natural Resource Concern. Laboratory Publication. Report No. 69. US Department of Agriculture, Agricultural Research Service, National Sedimentation Laboratory, Oxford, MS.

Interpretive Summary: Ephemeral gullies serve as a major source of sediment and are effective links transferring sediment and associated agrichemicals from upland areas to stream channels. USDA-NRCS has developed support practices for control of sheet and rill erosion that are also applied to treat ephemeral gully erosion, but technology and tools do not exist to account for the benefits and effects of these practices on soil and water quality by treating ephemeral gullies. Practices specifically developed to treat ephemeral gully erosion need further testing, including when used in conjunction with sheet and rill erosion control practices. An assessment of the national scope of ephemeral gully erosion using existing data from NRI, CEAP, PRS, national surveys and watershed studies was performed. As a result of this assessment, recommendations are provided with the intent to minimize any additional work required associated with including ephemeral gullies in conservation planning and reporting and to provide direction for the development of ephemeral gully technology and its inclusion into NRCS tools and models. Resources were identified as necessary to incorporate ephemeral gully erosion prediction and treatment technology into RUSLE2 or WEPP, watershed models, national assessment procedures such as NRI, and CEAP national and watershed assessment studies. At targeted locations, NRCS field office staff will be needed to collaborate with ARS in collecting supplemental ephemeral gully erosion data sets for use in tool development and calibration. Additional funding will be needed to conduct research on selected watersheds for characterizing ephemeral gully erosion sites, and for developing and testing conservation practices specifically designed for ephemeral gully erosion control.

Technical Abstract: Recent studies indicate that ephemeral gully erosion may be a significant form of erosion and source of sediment on cropland in the U.S. (averaging around 40% of the sediment delivered to the edge of the field in some documented studies). USDA-NRCS has developed support practices for sheet and rill erosion that are also applied to treat ephemeral gully erosion, but technology and tools do not exist to account for the benefits and effects of these practices on soil and water quality by treating ephemeral gullies. Practices specifically developed to treat ephemeral gully erosion need further testing, including when used in conjunction with sheet and rill erosion control practices. Subjective observations will continue to be used to satisfy quality criteria in lieu of scientifically defensible, quantitative methods. Non-scientific methods for accounting for and treating ephemeral gully erosion will be used, such as applying a simple multiplier factor to sheet and rill erosion predicted by RUSLE2 or WEPP. An assessment of the national scope of ephemeral gully erosion using existing data from NRI, CEAP, PRS, national surveys and watershed studies was performed. As a result of this assessment, recommendations are provided with the intent to minimize any additional work required associated with including ephemeral gullies in conservation planning and reporting and to provide direction for the development of ephemeral gully technology and its inclusion into NRCS tools and models. Resources are needed to incorporate ephemeral gully erosion prediction and treatment technology into RUSLE2 or WEPP, watershed models, national assessment procedures such as NRI, and CEAP national and watershed assessment studies. At targeted locations, NRCS field office staff will be needed to collaborate with ARS in collecting supplemental ephemeral gully erosion data sets for use in tool development and calibration. Additional funding will be needed to conduct research on selected watersheds for characterizing ephemeral gully erosion sites, and for developing and testing conservation practices specifically designed for ephemeral gully erosion control.