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Berlin Environmental Atlas

01.12 Soil Functions (Edition 2006)

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01.12.6 Efficacy of Soils for the Fulfillment of the Natural Soil Functions and the Archival Function

Description

Maps 01.12.1 through 01.12.5 provide an evaluation of the efficacy of soils with regard to their individual natural soil functions and their archive function. For the consideration of soil protection aspects in primary land-use planning, it is useful, however, to bring these evaluations together into an overall evaluation. The goal of the present map is therefore to evaluate the efficacy of the soils not only with regard to these individual functions, but also as a whole. Sections which are of great overall significance with regard to their performance and efficacy, and hence, too, for soil protection, are stressed particularly.

Methodology

A general problem for the combination of all five soil functions is the fact that within each of them, the same soil qualities are evaluated differently, and to some extent even oppositely. Thus for example, the habitat function for natural vegetation evaluates damp/wet, near-natural and rare sites as high, i.e. it favors extreme sites, whose yield function for cultivated plants is, by contrast, evaluated as the lowest. Among the sites evaluated as high for the archival function for natural history are very dry dune sites, while in terms of the filtration and buffering function, the regulatory function for the water balance, and the yield function the same sites are classed as very low.

Another problem is that due to the evaluation methodology chosen for the individual functions, sections of very different sizes have been evaluated as medium or high for a particular functions (cf. Figure 1). Thus for example, large parts of the city area were evaluated "high" with regard to their buffering and filtration function, while with regard to the archival function, only very few sections show a high efficiency. The result is that while in principle the five soil functions each carries equal weight in the final evaluation, some soil functions, primarily the buffering and filtration function and the regulatory function for the water balance, affect the final result more strongly than others.

Breakdown of the Berlin area by evaluation for different soil functions (without streets and waters)
Fig. 1: Breakdown of the Berlin area by evaluation for different soil functions (without streets and waters)

Excel
[Statistical base of Figure 2 is also available as Excel-File (MS-Excel is required).]

The three-level evaluations of the individual functions constitute the basis for the final evaluation. An evaluation of low (1), medium (2), or high (3) for each soil function thus exists for each section in the city. As criteria for the combined evaluation, the individual evaluations were added up, and also the number of times that each section was evaluated as high for a soil function was counted.

Several possible methods were tested alternatively for the evaluation of the efficacy of the soils in the fulfillment of the natural soil functions. In the procedure that was ultimately used, both the frequency of the highest evaluation (level 3) and the sum of the evaluations were taken into account for the overall evaluation (cf. Table 1). All soil functions have an equal influence on the overall evaluation; no weighting was carried out.

Tab. 1: Evaluation of efficacy, based on frequency of the highest evaluation level, and the sum of evaluations
Criteria Efficacy of the soils
  Evaluation Designation
Low mean efficacy for the 5 soil functions (sum of individual evaluations < 9,
and no high rating for any function)
1 low
Medium mean efficacy for the 5 soil functions (sum of individual evaluations 9 - 10, or a high rating for only one function)
hohe Leistungsfähigkeit bei nur einer Funktion)
2 medium
Above-average mean efficacy for the 5 soil functions (sum of individual evaluations > 10,
or a high rating for more than one function)
3 high
Tab. 1: Evaluation of efficacy, based on frequency of the highest evaluation level, and the sum of evaluations

This method is designed to reduce the disadvantages and defects of the other possible methods. The dominance of the regulatory function for the water balance and the buffering and filtration function is no longer emphasized so strongly here. Sections which have an evaluation of 3 (high) for only one soil function, but nonetheless have a high combined evaluation, can still attain the highest evaluation level.

Map Description

Sections with high efficacy predominate on the plateaus in the north and south, the Spandau Forest and the Gosen Meadows. On the other hand, heavily populated areas with low rates of near-naturalness show low to medium efficacy. The dominance of the regulatory function for the water balance and for the buffering and filtration function is particularly noticeable on the plateaus.

Sections for the evaluation of the efficacy of the soils for the fulfillment of their natural functions and the archive function, per use class (incl. impervious sections without streets and waters, not all uses, are shown)
Fig. 2: Sections for the evaluation of the efficacy of the soils for the fulfillment of their natural functions and the archive function, per use class (incl. impervious sections without streets and waters, not all uses, are shown)

Excel
[Statistical base of Figure 2 is also available as Excel-File (MS-Excel is required).]

Soils with a special value with regard to efficacy are primarily located in forests, allotment gardens and agricultural areas. But there are also residential areas with an open structure in which it can be assumed that near-natural soils have remained unchanged, and which in some cases show high efficacies (cf. Figure 2). Due to their uses, however, many of these areas are impervious.

Area shares for the evaluation of the efficacy of soils in the fulfillment of their natural soil functions and the archive function, per use class (incl. impervious sections without streets and waters, not all uses, are shown)
Fig. 3: Area shares for the evaluation of the efficacy of soils in the fulfillment of their natural soil functions and the archive function, per use class (incl. impervious sections without streets and waters, not all uses, are shown)

Excel
[Statistical base of Figure 3 is also available as Excel-File (MS-Excel is required).]

In the use categories allotment gardens, meadow/pasture, farmed fields and parks/cemeteries, however, many sections have received high efficacy evaluations, with respect to their total areas (cf. Figure 3).

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