There is growing interest in studying the impact of alternative agricultural management practices on runoff and soil loss under future climate change scenarios. In order to address this interest, it is important to demonstrate that runoff and soil loss can be accurately simulated under existing climates based on comparisons between modeled and experimental results. This study calibrates and validates the Water Erosion Prediction Project (WEPP) model to quantify the accuracy of predicting growing season runoff and soil erosion in agricultural hillslopes based on comparisons with experimental data from five Minnesota hydrologic unit code 12 watersheds. In order to accurately predict runoff and soil erosion in each watershed, the baseline effective hydraulic conductivity (Kbe), interrill and rill erodibility (EIR and ER), and monthly precipitation standard deviations (Pstdev) were calibrated in WEPP using observed runoff and total suspended solids data from five Minnesota Discovery Farms field sites. Before calibration, Nash–Sutcliffe model efficiency (NSE) and percent bias (PBIAS) values for predicted versus measured monthly average total runoff (Ravg-T), runoff ratios (RRT), and total soil loss were generally not in acceptable ranges. After calibration, the NSE values showed very good fits between measured and predicted monthly Ravg-T (0.64–0.98), RRT (0.66–0.93), and soil loss (0.58–0.80). PBIAS values were also within acceptable ranges for Ravg-T and RRT (±25%) and soil loss (±55%), except for RRT at site BE1. NSE and PBIAS values during validation were within acceptable ranges, except for RRT at site BE1. These findings suggest that the WEPP hillslopes calibrated in this study are sufficiently robust to accurately predict monthly runoff and soil erosion in Minnesota agricultural fields during the growing season.
|Original language||English (US)|
|Journal||Journal of the American Water Resources Association|
|State||Accepted/In press - 2023|
Bibliographical noteFunding Information:
This work was funded by the MN Clean Water Land and Legacy Act for the MN Board of Water and Soil Resources SWIFT #176095 project entitled: Operationalization of Residue, Cover Crop and Daily Erosion Project (DEP) and Wind Erosion Prediction System (WEPS) Estimates for Minnesota Agricultural Counties and DEP in Forested Regions.
© 2023 The Authors. Journal of the American Water Resources Association published by Wiley Periodicals LLC on behalf of American Water Resources Association.
- agricultural runoff
- growing season
- model accuracy
- soil loss