Risk Assessment Methodologies of Soil Threats in Europe

9. Conclusions
The soils in Europe are under increasing stress. The release of the European Strategy on Soil
Protection in 2006 has put the protection of this natural resource high on the political agenda of
many countries. However, as soil is an unmoving mass and many processes leading to soil
degradation occur before the degradation becomes visible, the evaluation of soil degradation is
complex. Therefore, many risk assessment methodologies (RAMs) were developed, of which
many are (very) complex in the sense of data requirements, software capacities and expert
interpretation. From the RAMSOIL project the following conclusions were drawn:
1. Many different soil RAMs are used by only a limited number of countries within EU-
27.
2. Most of these RAMs are incomplete, i.e., they quantify process rates or states of the
soil threat under consideration rather than risks, i.e. the probability of occurrence of
unwanted soil degradation. This complicates the evaluation of options for
harmonization of soil RAMs.
3. Many different RAMs have common elements, yet differ in comprehensiveness,
complexity and in spatial and temporal scales.
4. Using different RAMs may have large consequences with regard to affected area,
spatial distribution and patchiness of the threat occurring. A case-study on soil erosion
in Romania showed differences in affected areas up to 30%.
5. There are various interpretations of the term ‘harmonization’ ranging from the strict
definition of making results comparable or compatible to standardizing protocols. The
ambivalent use of the term harmonization in international literature complicates the
assessment of options for harmonization.
6. Harmonization of RAMs, i.e. making results comparable or compatible is complicated
by differences in the notion of the threat, data collection, data processing, data
interpretation and risk perception.
Although, given the common (scientific) grounds of many soil RAMs, our impression is that in
practice harmonization of soil RAMs will be very laborious and most likely in the end will
result in some kind of compromise. To maintain the site specificity and cultural identity of
regionally developed RAMs we suggest two options that may facilitate unequivocal
identification of risk (or priority) areas for soil threats:
1. a two-tier approach where tier 1 is at a relatively low spatial resolution, and tier 2 is a
more detailed assessment.
2. generic harmonization, i.e. combining standardization and harmonization.
Ad. 1. A tiered approach for the identification of risk areas for soil threats was also suggested
by Eckelmann et al. (2006). They suggest to firstly provide broadly defined zones at Tier 1
level, within which specific measures have to be planned at Tier 2 level. Also, the landslides
scientific community already uses a Tiered approach, which paves the way for the other soil
threats to use a comparable approach. However, in the landslide community a slightly different
version of the Tiered approach is followed compared to the suggestion of Eckelmann et al.
(2006). In the landslides scientific community Tier 1 is a generic landslide susceptibility map
using a heuristic weighting-rating model, Tier 2 is a landslide susceptibility map (by types)
using a multivariate statistical model and Tier 3 is a landslide susceptibility/hazard map using a
process-based model. Recently, an overview of soil threats in Europe including maps at
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