Enhanced field-scale characterization for watershed erosion assessments

Authors: MOMM, HENRIQUE - Middle Tennessee State University; Bingner, Ronald - Ron; Wells, Robert - Rob; PORTER, WESLEY - Middle Tennessee State University; Witthaus, Lindsey; DABNEY, SETH - Retired ARS Employee

Submitted to: Journal of Environmental Modeling and Software
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2019
Publication Date: 5/6/2019
Citation: Momm, H.G., Bingner, R.L., Wells, R.R., Porter, W.S., Yasarer, L.M., Dabney, S.M. 2019. Enhanced field-scale characterization for watershed erosion assessments. Journal of Environmental Modeling and Software. 117:134-148. https://doi.org/10.1016/j.envsoft.2019.03.025.
DOI: https://doi.org/10.1016/j.envsoft.2019.03.025

Interpretive Summary: Watershed-scale simulation technology can be used to identify and track sediment loads that originate in fields and are then routed downstream. This technology allows for quantification of the impact of individual and/or integrated management practices throughout the watershed. Watershed simulation technology was used to simulate the erosion from all fields in the watershed with the highest erosive fields identified for further study with advanced field erosion technology. Using an integrated modeling approach, these targeted fields can be analyzed based on multiple management, landscape, and combined management-landscape conditions. The erosion from these targeted field can then be integrated back into the watershed simulations to quantify the overall effect of enhanced field characterization on sediment loads at the field and watershed scales. Methods for identification of critical sediment producing areas using integrated field erosion and watershed sediment transport models can be used to support the development, evaluation and implementation of conservation management plans impacting the entire watershed by action agencies.

Technical Abstract: Watershed-scale simulation technology can be used to track sediment loads that originate in fields and are then routed downstream. This technology allows for quantification of the impact of individual and/or integrated management practices throughout the watershed. An example of this technology is the Annualized Agricultural Non-Point Source watershed pollutant load model (AnnAGNPS). In AnnAGNPS, the watershed is subdivided into basic modeling units (fields) in which all spatially and temporally varying physical parameters are assumed to be homogeneous. This simplification is needed to provide conservation practice assessment at the watershed scale within a reasonable amount of time for data preparation and program execution. Conversely, the Revised Universal Soil Loss Equation, Version 2 (RUSLE2) can estimate sediment yield at the field scale with enhanced capabilities in describing field variations of farming management, topography, and soil properties. In this study, an integrated approach was developed and evaluated involving both models for enhanced characterization of individual fields while accounting for the watershed-wide integrated intra fields effect when routing sediment loads through the watershed. The identification of fields producing high erosion rates within the watershed can be initially performed using AnnAGNPS. Using an integrated modeling approach, these targeted fields can be described through multiple scenarios of RUSLE2 slope profiles and analyzed based on multiple management, landscape, and combined management-landscape conditions. These RUSLE2 scenarios can then be integrated into AnnAGNPS watershed simulations to quantify the overall effect of enhanced field characterization on sediment loads at the field and watershed scales. Methods for identification of critical sediment producing areas using integrated RUSLE2 erosion and AnnAGNPS sediment transport models can be used to support the development and evaluation of conservation management plans impacting the entire watershed.