Usle2D is designed to calculate the LS-factor in the Universal Soil Loss equation from a grid-based Digital elevation model. In a real two-dimensional situation overland flow and the resulting soil loss does not really depend on the distance to the divide or upslope border of the field, but on the area per unit of contour length contributing runoff to that point. The latter may differ considerably from the manually measured slope length, as it is strongly affected by flow convergence and/or divergence. Usle2D overcomes this problem by replacing the slope length by the unit contributing area. Usle2D provides different routing algorithms for calculating the contributing area and various LS-algorithms.

The linkage of Usle2D in a GIS offers several advantages to the one-dimensional and/or manual approach; it may account for the effect of flow convergence on rill development and it has advantages in terms of speed of execution and objectivity. The linking of Usle2D with a GIS facilitates the application of the (R)USLE to complex land units, thereby extending the applicability and flexibility of the (R)USLE in land resources management.

Despite the widespread acceptance of the (R)USLE, it has two important disadvantages: (i) the impossibility to predict where the eroded material will be deposited and (ii) although tillage erosion is shown to be a major soil degradation process, the effect of soil erosion by tillage is not accounted for. An extended version of Usle2D, with a deposition and tillage procedure, called WaTEM (Water and Tillage Erosion Model) was therefore implemented.