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United States Department of Agriculture

Agricultural Research Service

Research Project: UNDERSTANDING AND PREDICTING THE IMPACT OF AGRICULTURE ON THE ENVIRONMENTAL INTEGRITY OF MANAGED WATERSHEDS Title: Cheney Lake CEAP Project: Validation/Calibration, Nutrients

Authors
item Frees, L. -
item Theurer, F. -
item Bingner, Ronald
item French, L. -

Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: May 20, 2010
Publication Date: June 27, 2010
Citation: Frees, L.D., Theurer, F.D., Bingner, R.L., French, L. 2010. Cheney Lake CEAP Project: Validation/Calibration, Nutrients. In: Proceedings of the 2010 Federal Interagency Sedimentation Conference June 27-July 1, Las Vegas, Nevada. 2010 CDROM.

Interpretive Summary: AnnAGNPS was used to analyze Cheney Lake Watershed, a Special Emphasis Watershed in Kansas, during the Conservation Evaluation Assessment Project (CEAP). Its major finding was the significance of ephemeral gully erosion. In order to ensure confidence in its findings, a sequence of calibration in steps for the water runoff and pollutant loadings was done in a fixed order. This paper describes the calibration stages used to calibrate the nutrients, why certain steps were necessary, the results, and insights as to what led to the results and what can or should be done to improve the results. The first, most likely source of loss of ability to calibrate and validate to measured results, is to make certain that model inputs sufficiently describe the spatial and temporal variables. Second, better and more frequent direct measurements of sediment and nutrients should be made whenever water quality is important, including particle-size measurements. Third, improvement is needed in describing the initialization of background soil organic and inorganic nutrients that better reflect the spatial variability within the watershed. Fourth, a baseflow feature that addresses the percolation into the vadose zone, groundwater movement, and interception of the top of the water table by the channel is needed within models, if a complete analysis of dissolved chemicals is important or when calibrating or validating.

Technical Abstract: The Annualized Agricultural Non-point Pollutant Source (AnnAGNPS) was used to analyze some of the Special Emphasis Watershed during the Conservation Evaluation Assessment Program (CEAP). Its major finding was the significance of ephemeral gully erosion. In order to ensure confidence in its findings, a sequence of calibration in steps for the water runoff and pollutant loadings was done in a fixed order. This paper describes the calibration stages used to calibrate the nutrients, why certain steps were necessary, the results, and insights as to what led to the results and what can or should be done to improve the results.

Last Modified: 10/20/2014
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