Refining Rainfall Erosivity Estimation: Methodological improvements towards more accurate soil erosion assessments

Rainfall erosivity is a fundamental parameter in estimating soil erosion as it quantifies the potential of raindrops to detach soil particles and make them available for subsequent transport by surface runoff. Erosivity depends mainly on the intensity, duration, and energy of precipitation events, which directly affect the impact of raindrops on the soil surfaces and runoff. The most common methods for identifying erosive events emphasize short-duration, high-intensity rainfall events, while introducing critical thresholds for characterizing erosive events, such as the 30-minute maximum rainfall intensity (I30) and storm separation criteria (see e.g. Wischmeier and Smith, 1978, Foster et al., 1981 and Renard et al., 1997).Nevertheless, both historical and recently proposed frameworks occasionally consolidate rainfall events that should be disaggregated according to the established six-hour dry period threshold, leading to overestimation of rainfall event durations and erosivity factors. The present study aims at refining the identification and analysis of erosive rainfall events, a key component of soil erosion prediction, by introducing an alternative approach that strictly adheres to the original criteria introduced by Wischmeier and Smith (1978) and Renard et al. (1997), ensuring precise segmentation of rainfall events when rainfall accumulation is below the 1.27 mm threshold over a six-hour period.The proposed method classifies rainfall events as erosive when total rainfall exceeds 12.7 mm or meets intensity thresholds of 6.4 mm in 15 minutes or 12.7 mm in 30 minutes. Comparative analysis with existing approaches demonstrates improved alignment with fundamental criteria while addressing modern computational challenges, contributing to the advancement of soil erosion prediction by bridging historical methodologies with contemporary analytical precision.ReferencesWischmeier, W.H., Smith, D. D. (1978) Predicting rainfall erosion losses: A guide to conservation planning. Agric. Handb. 537. US Gov. Print. Office, Washington, DC.Foster, G.R., McCool, D.K., Renard, K.G., Moldenhauer, W.C. (1981) Conversion of the universal soil loss equation to SI metric units. J. Soil Water Conserv. 36, 355–359.Renard, K., Foster, G., Weesies, G., McCool, D. and Yoder, D. (1997) Predicting Soil Erosion by Water: A Guide to Conservation Planning with the Revised Universal Soil Loss Equation (RUSLE). US Department of Agriculture, Agriculture Handbook No.703USDA, USDA, Washington DC.