Rainfall erosivity in Slovenia: Sensitivity estimation and trend detection

Area of Science:

• Environmental Science
• Hydrology
• Soil Science

Background:

• Slovenia exhibits significant rainfall erosivity variability, with maximum annual values exceeding 10,000 MJ mm ha⁻¹ h⁻¹ yr⁻¹.
• Understanding rainfall erosivity is crucial for soil erosion management in the region.

Purpose of the Study:

• To analyze trends in rainfall erosivity (R-factor) across Slovenia.
• To assess the impact of calculation parameters on R-factor values.
• To compare local kinetic energy equations with the RUSLE standard.

Main Methods:

• Analysis of five-minute rainfall data from 10 Slovenian stations (over 443 station-years).
• Detection of R-factor trends using monthly, half-year, and annual erosivity values.
• Sensitivity analysis of rainfall threshold parameters and kinetic energy equations.

Main Results:

• Most identified rainfall erosivity trends were statistically insignificant (p > 0.05), though more trends were positive than negative.
• A rainfall threshold parameter (12.7 mm) can account for up to 10% of average annual R-values.
• Local kinetic energy equations yielded ~20% higher annual erosivity than the RUSLE standard.

Conclusions:

• Rainfall erosivity trends in Slovenia are largely insignificant, but variability is high.
• Calculation methodologies, including rainfall thresholds and local energy equations, significantly influence R-factor outcomes.
• Region-specific equations are recommended for accurate rainfall erosivity assessment in Slovenia.