Specific Assessment of Soil Functions
For the solution of these two tasks – a differentiated assessment of soil functions, and implementation of soil-function assessment in the Planning Notes – the following considerations and work steps have been implemented in Map 01.13: First of all, the soil functions (Maps 01.12.1 through 01.12.5) have been weighted differently, in accordance with their significance to the specific conditions in Berlin (in detail in Gerstenberg et al., 2007and 2015):
- Archive soils and soils which offer site potentials for rare and near-natural plant communities are classified as deserving of extraordinary protection, due to their non-restorability.
- Soils which are efficient with respect to the regulation function for the water balance and the buffering and filtration function are deserving of protection generally; the significance rises at these locations still further if these two functions appear together, with a high assessment.
- Soils which show a high yield function for crops exist in agriculturally used sections.
This establishes a prioritization regarding the significance and sensitivity of soil functions.
Moreover, soils with considerable potentials for material contamination (e.g. sewage farms) are removed from the assessment process regarding the regulation, filtration and buffering functions as well as the yield function for crops, since they represent a possible source of burden for the groundwater and the food chain.
For the assessment of soils with regard to their protection-worthiness, five protection categories have been established, graduated from the maximum to the lowest protection status. They imply consequences for requisite action, and recommendations regarding interventions in the soil due to development plans and construction projects.
The protection requirements of soils are classified into the following soil protection categories:
- maximum protection level,
- very high protection level,
- high protection level,
- medium protection level and
- low protection level (soils with no special requirements).
As in the case of all Environmental Atlas maps on the topic Soil, except the Imperviousness map, the information and assessments shown here refer to the pervious portion of the soil. However, since the extent of imperviousness is of great importance, the degree of imperviousness is not shown only in the display of factual data, but also in the coloring of sections by protection category: these are shown in three degrees of intensity, decreasing with the increasing degree of imperviousness.
The imperviousness levels 5 % and 30 % have been chosen here as the boundaries between the three categories of intensity shown by this shading: with imperviousness of 5 % or less, a section can be considered completely pervious, interrupted only by scattered buildings, pathways or the like; this includes forests, fields and pastureland. Allotment gardens, single-family homes, parks and other open areas, which may also have near-natural soils, dominate in the medium-level category with an imperviousness level of more than 5 % up to 30 %. Imperviousness greater than 30 % occurs primarily in residential and commercial sections, and in transportation areas, which for the most part have no natural soil associations at all any more.