**2. The SCALES model**

#### **2.1 Background**

SCALES provides a mapping of soil erosion hazard which offer local land managers spatialized data at regional scale while having high accuracy on the local scale. As a result, hazard assessment is carried out on erosion source areas identified by elementary spatial units such as agricultural parcels.

In many European regions, agricultural land is structured visually and physically by the juxtaposition of these parcels. Each of these units is an erosion system whose activation depends less on near environment than on the distinct features of each parcel. By mapping the hazard at the scale parcel, the aim is to provide land management organizations with data so as to rationalize the Fig.ht against erosion hazard not at catchment area scale, but directly at source area level.

Taking into account anthropic activity in assessing hazard means resorting to the concept of agricultural practices as opposed to that of land cover, unlike all others erosion models at regional scale. The idea here is to re-contextualize hazard by looking at agricultural practices strongly structured along annual cycles (duration and management of intercrop) and multiannual cycles (crop rotation).

Initial, intermediate and final data from the model needs to be implemented as numeric georeferred informations, usable with GIS and presented at different spatial resolutions showing the main agricultural, administrative and hydrological divisions of the area.

Since diagnostic of erosion hazard is based on data susceptible to change on a short or medium time, the model needs to be designed in order to easily generate data and hazard level updates. This perspective will then offer the possibility to develop an exploratory approach aiming to measure the positive or negative effects of a climatic tendency or a planned change in agricultural practices.

The SCALES approach can be reproduced where such agricultural practices as descrubed above occur and where the climate is a mild maritime one. In Europe, the application of the model can be carried out all along the Oceanic façade from the N-W of Spain until the South of England.
