Erosion Risk (RUSLE) Calculator
Estimate average annual soil loss from a slope or rehabilitation area using the Revised Universal Soil Loss Equation, A = R × K × LS × C × P, and read off a qualitative erosion-risk band. A planning tool for mine rehabilitation, tailings caps and disturbed-ground management.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the five RUSLE factors: R (rainfall erosivity), K (soil erodibility), LS (slope length-steepness), C (cover-management, 0–1) and P (support-practice, 0–1).
- Take each factor from local rainfall records, soil surveys, slope data and published regional tables — the result is only as reliable as these inputs.
- Read the annual soil loss A in t/ha/yr and the risk band; leave P blank for 1 (no support practice).
How it works
RUSLE multiplies five factors to give the long-term average sheet-and-rill soil loss: A (t/ha/yr) = R × K × LS × C × P. R measures the erosive power of rainfall, K how readily the soil detaches and washes away, and LS the effect of slope length and steepness (both increase erosion). C is the cover-management factor between 0 and 1 — bare disturbed ground approaches 1, while dense vegetation or mulch drives it far lower. P is the support-practice factor (0–1) for measures such as contour banks; 1 means no practice. The computed A is then classified into bands — very low (<2), low (2–10), moderate (10–20), high (20–50) and severe (>50) t/ha/yr — as a comparative risk guide.
Worked example
Worked example. A rehabilitated batter has R = 3000, K = 0.03, LS = 1.5, C = 0.1 (light cover established) and P = 1. A = 3000 × 0.03 × 1.5 × 0.1 × 1 = 13.5 t/ha/yr, which falls in the moderate band (10–20 t/ha/yr) — cutting the C factor with better cover would move it toward low.
Common mistakes
- Using factor values from another region or a different unit system — R and K in particular are region- and unit-specific and are not interchangeable.
- Setting C to 1 for a surface that actually has partial cover, which overstates loss; C drops sharply as vegetation or mulch establishes.
- Treating the answer as total erosion — RUSLE covers only sheet-and-rill erosion, not gullies, mass movement or single extreme storms.
Frequently asked questions
What does the C factor represent?
The cover-management factor compares soil loss under the actual cover to loss from continuously bare, tilled ground (C = 1). Established grass, mulch or rock armour can reduce C to a few percent, which is why it is often the biggest lever in rehabilitation design.
Are the risk bands standardised?
No single global standard exists; the bands here (very low/low/moderate/high/severe) are a common planning-level classification. Compare against your site's or regulator's tolerable soil-loss threshold rather than the band label alone.
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Tip: Enter any known values to calculate the remaining results.
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