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United States Department of Agriculture

Agricultural Research Service

Title: Application of the Annagnps Model to the Walnut Creek, Ia Ceap Benchmark Watershed

item Yuan, Yongping - USDA-ARS NTL SEDIMNT. LAB

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 5, 2006
Publication Date: May 5, 2006
Repository URL:
Citation: Dinnes, D.L., Jaynes, D.B., Karlen, D.L., Bingner, R.L., Yuan, Y. 2006. Application of the ANNAGNPS model to the Walnut Creek, IA CEAP benchmark watershed. 2006 USDA-ARS CEAP Watershed Assessment Study Annual Meeting. Available:

Technical Abstract: In 1991 the National Soil Tilth Laboratory (NSTL) began a comprehensive monitoring and environmental assessment research project within the Walnut Creek Watershed in Central Iowa as a part of the Management Systems Evaluation Area (MSEA) program. Since completion of MSEA, the NSTL has continued to monitor water quantity and quality for both tile drainage and streamflow within this row-crop dominated watershed, thus producing a continuous, long-term database. A nitrogen (N) fertilizer best management practice (BMP) was also evaluated from 1997–2000 at the sub-basin scale. This verified that using the late-spring nitrate test (LSNT) could reduce nitrate-N concentration in tile drainage discharge by over 30% compared to conventional N management practices. The Walnut Creek Watershed was subsequently selected as a benchmark research watershed for the Conservation Effects Assessment Project (CEAP) because of the database and known row-crop history. One part of this research plan included validating and verifying the Annualized Agricultural Non-Point Source (AnnAGNPS) pollution model by using the Walnut Creek Watershed databases. This presentation will summarize our experience with the AnnAGNPS model and present preliminary evaluations of the model’s performance within this tile-drained watershed.

Last Modified: 4/22/2015