Isoerodent surfaces of the continental US for conservation planning with the RUSLE2 water erosion model

Authors: MOMM, HENRIQUE - Middle Tennessee State University; Wells, Robert; ELKADIRI, RACHA - Middle Tennessee State University; SEEVER, THOMAS - Middle Tennessee State University; YODER, DANIEL - University Of Tennessee; MCGEHEE, RYAN - Iowa State University; Bingner, Ronald; DARNAULT, CHRISTOPHE - Clemson University

Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2025
Publication Date: 3/6/2025
Citation: Momm, H.G., Wells, R.R., Elkadiri, R., Seever, T., Yoder, D., Mcgehee, R.P., Bingner, R.L., Darnault, C.J. 2025. Isoerodent surfaces of the continental US for conservation planning with the RUSLE2 water erosion model. Science of the Total Environment. 253(108879). https://doi.org/10.1016/j.catena.2025.108879.
DOI: https://doi.org/10.1016/j.catena.2025.108879

Interpretive Summary: Conservation management planning for soil loss requires technology that represents the impact of climate on farm management practices and the implementation of conservation alternatives. Methods are needed to update the average annual rainfall erosivity for the entire continental US for use within the USDA Revised Universal Soil Loss Equation, Version 2 (RUSLE2) to assure consistency in erosion predictions for conservation planning. These methods will replace the laborious process of analyzing and processing data by hand to reproduce a smoothly and spatially varying average annual rainfall erosivity surface throughout the continental US. Initial products were developed based on information obtained from the US National Oceanic and Atmospheric Administration (NOAA) stations. The data was processed following a strict protocol adhering to RUSLE2 science documentation that includes utilizing existing precipitation normals, distance to the US coast, and continental elevation data to replicate the current RUSLE2 climate. The newly generated surfaces were compared to official surfaces and evaluated for smoothness. Results indicate agreement with RUSLE2 surfaces for absolute values but with slightly higher spatial and temporal smoothness. This approach provides the means for capturing long-term climatic variations impacting soil erosion in a consistent way and supports future updates to the RUSLE2 climate database. This also serves as a baseline for future enhancements in characterizing changing climatological drivers impacting soil erosion.

Technical Abstract: Soil erosion computation technology plays an important role in planning to prevent and mitigate soil loss and non-point source pollution from agricultural fields. In the US, the RUSLE2 erosion model is extensively used by conservationists to support efforts for adoption of new farm management practices and implementation of conservation alternatives. Within RUSLE2, the impact of precipitation is described by average annual rainfall erosivity (R) which is represented by a smoothly and spatially varying surface that covers the entire US, assuring consistency in erosion predictions for conservation planning. In the current RUSLE2 erosivity database, these surfaces were developed by a laborious process of analyzing and processing data by hand, so this had not been updated since 2001. In this study, a protocol to generate isoerodent surfaces for the continental US is proposed and evaluated. The methodology describes steps that integrate the official RUSLE2 calculations with proposed new methods. The newly generated surfaces were compared to official surfaces and evaluated for smoothness. Results indicate agreement with RUSLE2 surfaces for absolute values but with slightly higher spatial and temporal smoothness. Further refinements include the inclusion of small events, determination of spatially varying recurrence intervals, and consideration of two-axis trend interpolation enhanced with additional weighting accounting for data gaps, which gives more weight to weather stations that have more complete datasets. The protocol provides the means for capturing long-term climatic variations impacting soil erosion in a consistent way. This protocol supports forthcoming updates to the RUSLE2 climate database and serves as a baseline for future enhancements in the characterization of changing climatological drivers impacting soil erosion.