This simulation estimates long-term sheet and rill erosion on a hillslope using the Revised Universal Soil Loss Equation (RUSLE): A = R × K × LS × C × P. Annual soil loss A, expressed in tonnes per hectare per year, is the product of five empirical factors describing climate, soil, terrain, vegetation and management. The animated cross-section shows topsoil thinning upslope and sediment accumulating near the base over a 200-year run.
The control panel lets you set R (rainfall erosivity), K (soil erodibility), LS (slope-length and steepness), C (cover-management) and P (conservation practice), plus the number of slope cells and a Reset Soil button. Presets switch between bare tilled soil, row crop, pasture and forest. RUSLE underpins real conservation planning, helping farmers and agencies compare practices and keep soil loss within tolerable limits.
What does this simulator actually calculate?
It calculates A, the average annual soil loss in tonnes per hectare per year, using the RUSLE formula A = R x K x LS x C x P. The value updates live as you move the sliders, and the hillslope view illustrates how that loss thins the topsoil layer and deposits sediment near the slope base.
What is the RUSLE equation?
RUSLE, the Revised Universal Soil Loss Equation, multiplies five factors: rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C) and conservation practice (P). Each factor is dimensionless or carries units chosen so their product yields soil loss directly in tonnes per hectare per year.
What do the five sliders control?
R sets the erosive power of rainfall (50 to 1200 MJ.mm/ha/h/yr), K the inherent erodibility of the soil, LS the effect of slope length and gradient, C how much vegetation or residue protects the surface, and P the benefit of practices like contouring or terracing. Lower C and P values mean better protection and less erosion.
R quantifies the combined energy and intensity of rainfall over a year. More intense storms detach and transport more soil, so a higher R directly scales up calculated loss. In this model R ranges from a dry-climate value near 50 up to 1200 for very wet, storm-prone regions.
The cover-management factor C compares erosion under a given crop or vegetation to bare fallow soil. Dense forest or pasture can push C below 0.01, cutting loss by ninety-nine per cent versus bare ground (C near 1.0). Because A is a simple product, C acts as a powerful multiplier, which is why ground cover is the cheapest erosion control.
LS combines slope length and steepness into one term. Longer, steeper slopes give runoff more time and momentum to detach and carry soil, raising LS and therefore A. The slider spans 0.2 for short gentle ground up to 20 for long, steep terrain.
The A = R x K x LS x C x P calculation is the genuine RUSLE empirical model used in real conservation planning, so the headline soil-loss figure is realistic. The animated redistribution of soil across slope cells is a simplified illustration: it applies a stylised upslope-to-base gradient and is not a full process-based hydrological model.
The risk badge categorises the calculated A value: Low below 5, Moderate from 5 to 10, High from 10 to 30, and Severe above 30 tonnes per hectare per year. These thresholds reflect typical soil-loss tolerance levels, beyond which topsoil is lost faster than natural processes can rebuild it.
The visual applies a slope factor that increases from the base to the upslope edge, so upper cells erode faster while the lowest cells receive deposited sediment, shown in blue. This mimics how detached soil moves downhill and settles where the gradient flattens, a pattern seen on real cultivated hillsides.
Agronomists, soil conservation services and land planners use RUSLE to predict erosion under different crops and practices, then choose measures that keep loss within tolerable limits. It informs subsidy and stewardship schemes, contour and terrace design, cover-crop choices and the targeting of buffer strips on vulnerable fields.