Rainfall Erosivity based on High Temporal Resolution Rainfall Gauge Records in Oklahoma

This project aims to generate long-term average monthly rainfall erosivity by aggregating storm-level erosivity estimates over the period 1995–2023 (29 years). Individual storm erosivity was calculated using the rainfall kinetic energy equation (USDA-ARS, 2013), based on high-temporal-resolution (5-minute interval) rainfall data collected from 91 Oklahoma Mesonet sites.

The resulting dataset supports soil loss predictions using the Universal Soil Loss Equation (USLE) model. Given the limited availability of benchmark datasets derived from traditional pluviometers, this rainfall erosivity dataset, based on measurements collected by modern instruments at fixed, fine time intervals, provides a reference for evaluating erosivity estimates derived from coarser precipitation data (≥30-minute resolution).

Additionally, the dataset includes an updated EI distribution, which was originally developed by the USDA (Wischmeier & Smith, 1965) to estimate the seasonal land cover and management factor (C) in the Universal Soil Loss Equation (USLE). In the United States, the EI distribution combined with average annual rainfall erosivity expressed in U.S. customary units is used by owners of small construction projects (less than 5 acres) to determine whether their site qualifies for the Low Erosivity Waiver (LEW) under the National Pollutant Discharge Elimination System (NPDES), as authorized by the EPA’s Clean Water Act.