Risk Assessment Methodologies of Soil Threats in Europe

The majority (7 out of 11) of the inventoried RAMs for soil erosion uses the USLE or modified forms of
this model (figure 2.2). Three RAMs use factorial approaches in the form of a hierarchical multifactorial
classification (INRA Approach in France, PWER 1 and AWER 2 indicator methods in Poland, and
CORINE). Three RAMs use process-based models (EROSION 3D and SWAT in Poland; ICECREAMS
in Finland, and PESERA).
As a consequence of the prevalent application of the USLE, most RAMs only consider water erosion, and
then limited to sheet and rill erosion. One exception is the RAM of Belgium, which uses separate model
components for channel and tillage erosion in conjunction with the RUSLE. RAMs which use processbased
models also consider channel erosion, deposition, transport of chemicals, effects of snow/ice and
and/or wind erosion.
Only in one RAM (Norway), the erosion model is calibrated. Only two RAMs validate the method used
for erosion risk assessment, by expert judgement in combination with field visits (the INRA Approach-
France) and field measurements at the field and catchment scale (PESERA). This implies that the quality
of the model output used in the majority of RAMs is unknown, nor in terms of soil loss estimates, nor in
terms of erosion risk classes.
2.4 Data interpretation
The responses to the questionnaires and literature (Boardman and Poesen, 2006; OECD, 2008a,b) reveal
that classification systems for soil erosion risk vary widely between European countries. Classifications
may employ ordinal or scalar scales, depending on whether the erosion rate is expressed in qualitative (e.g.
‘low erosion risk’, ‘medium erosion risk’, ‘high erosion risk’, ‘very high erosion risk’, as in the system of
Norway) or quantitative terms (t/ha/y). Of the 18 countries for which risk classification systems were
found, 9 use quantitative classes. Both qualitative and quantitative systems usually have 4 to 6 classes.
The documentation of risk classifications often does not provide descriptions of classes or class limits,
which makes it difficult to interpret (qualitative or quantitative) erosion rates in terms of risk (Box 2.1).
This makes the comparison of risk classification systems between countries difficult.
Figure 2.3 Output variables of risk assessment methods for soil erosion in EU member states.
source: RAMSOIL thematic questionnaires.
1 Potential Water Erosion Risk (Józe Faciuk and Józe Faciuk, 1995)
2 Actual Water Erosion Risk (Józe Faciuk and Józe Faciuk, 1996)
10