SUITMA 2005 Cairo - German soil evaluation systems and the new TUSEC method for the alpine space
SUITMA 2005 Cairo
| This abstract is about one of the papers of the Methodology and classification theme of the SUITMA 2005 symposium. |
| Susanne David,i | Andreas Lehmann,i |
| Karl Stahr.i |
- i - Institute for soil science and land evaluation, Hohenheim University, Stuttgart, Germany.
Contents
Abstract
Many soil evaluation systems were developed for different purposes in several countries. The new TUSEC-Method, which was developed in the EU INTERREG IIIB project TUSEC-IP[1], focuses on soils in city regions of the alpine space. The results of this new soil evaluation method are passed to urban planners to take this information into account in urban planning processes. Up to now, soil protection plays only a minor role especially within urban areas, and an improvement of this situation is urgently needed, e.g. to minimize health risks for citizens. The TUSEC-Method was developed to become implemented in cities of the entire alpine space and adjacent regions, since the alpine space requires a very gentle spatial development: Steep slopes and fluvial plains with a high risk of becoming flooded are the main geomorphologic units. On the other hand, there is a high development pressure on areas since many cities show increasing numbers of inhabitants due to migration of people quite often. A sustainable urban development is urgently needed. To meet planner’s approaches, two different methods were developed within TUSEC-IP. Both methods use different data sources and algorithms and thus produce results with different reliabilities according to planner’s requirements. A case study of a small village in southwestern Germany shows how soil evaluation results can be considered in the urban planning process.
Introduction
In Germany, the legislation demands an economic use of land and thus soils. This statement is contained in different laws and procedures regulated by law, e.g. the Federal Soil Protection Act and the Environmental Impact Assessment. The latter, for example, aims at describing and evaluating the effects of construction projects on soils. This can be done by soil evaluation, which is based on a description of present soil properties. However, these methods can be used to describe future scenarios concerning future uses of soils, too. Since no single method is recommended by law, many different soil evaluation systems have been developed so far (e.g. HLUG, 2004; Hochfeld, 2004; Außendorf et al. 2003; BVB, 2000). These methods differ with regard to the aims of the soil evaluation, input parameters and the combinations of the latter.
The project TUSEC-IP (Technique of Urban Soil Evaluation in City Regions - Implementation in Planning Procedures) develops a soil evaluation method for urban areas of the alpine space. The evaluation results are implemented into the planning process by partner cities to improve the consideration of soils within this process.
Legal background
The legal framework of soil protection and soil evaluation in Germany is given by the Federal Soil Protection Act, which came into force in March 1998. In paragraph 2 of the framework, it contains a list of functions that soils may fulfill. Natural functions serve as a basis for life and a habitat for people, animals, plants and soil organisms; as part of natural systems, especially by means of its water and nutrient cycles; and as a medium for decomposition, balance and restoration as a result of its filtering, buffering and substance-converting properties, and especially groundwater protection. There are functions that pertain to archiving natural and cultural history. Furthermore, there are functions useful to man and society including serving as a medium that holds deposits of raw materials, settlement and recreation; agricultural and silvicultural use; and land for other economic and public uses, for transport and for supply, provision and disposal. The focus of these functions, however, changes from one interpreter to another.
The project TUSEC-IP
TUSEC-IP is an INTERREG IIIB project funded by the European Union. Ten partners from different countries situated in and around the Alps collaborate together. They aim to develop strategies for a sustainable spatial development of urban areas and to implement them in planning procedures (www.tusec-ip.org). Background of this effort especially on alpine cities is the high pressure on areas and thus soils due to urban sprawl on one hand and limited space due to the geomorphic situations of the alpine space, where mainly steep slopes or floodplains are formed on the other hand. Due to this, a sustainable urban development and thus soil protection still plays only a minor role in the urban planning process.
By providing and testing a soil evaluation method especially for urban areas, TUSEC-IP improves the consideration of soils within the planning process. The evaluation method is developed by scientific institutions according to the requirements of the partner cities and its planners, whereas the planners implement the results (www.tusec-ip.org).
Soil evaluation
At present, many soil evaluation methods for different purposes have been developed by different institutions of several countries. In Germany, a widely used soil evaluation method developed in Baden-Württemberg (Germany), is the so called “Heft 31” (Pamphlet 31). It allows the evaluation of agriculturally used soils in southern Germany (Lehle et al., 1995). However, many methods exist by now. E.g. the Bundesverband Boden (BVB) published short descriptions of methods having different data sources (BVB, 2000). The Hessische Landesamt für Umwelt und Geologie (HLUG) summarized methods based on existing evaluation data (HLUG, 2004). Außendorf et al. (2003) enclosed also silvicultural areas.
Since urban soils are exposed to specific and intensive processes like addition or loss of material, loosening or compaction, they demand special consideration. The TUSEC-IP evaluation method takes them into account by the definition of class boundaries for example (Lehmann, et al., 2005).
Within TUSEC-IP, two soil evaluation methods were developed in order to take into account the heterogeneous land information of different cities with different planning areas in different countries. Thus, the so-called A-Level is based on mapped data. Hence, its results are detailed and highly reliable. They can be considered in the legally oblige land use plan having a scale between 1:10.000 and 1:1.000 (Lehmann et al., 2005). Some of the algorithms for the evaluation of soil functions were published in common methods already, but became adapted to fit the conditions of the project (Lehmann et al., 2005). The so-called B-Level runs with available data. Hence it can be used for reconnaissance. Its orientating results are suitable for less detailed scales.
Furthermore, TUSEC-IP provides the evaluation of two soil performances, which are not mentioned by the German law. However they improve conditions for inhabitants of cities or are valuable for planners. One soil performance is the climate regulation, which is caused by evapotranspiration of water contained in soil pores (Lehmann et al., 2005). The evaporation causes a cooling effect. Additionally, an increase of air humidity may occur. Especially the cooling effect improves the urban climate, which is generally characterized by higher temperatures than surrounding areas. This improves conditions for human’s life in cities. Due to lower temperatures in winter, the effect becomes strongly reduced in that season (Lehmann et al., 2005).
The other soil performance is the alternative stormwater management. Cities can use their soils to infiltrate the precipitation to reduce runoff. Hence, urban drainage systems can be dimensioned properly and sealing can be minimized. Furthermore, costs for building drainage systems can be reduced.
Implementation and a case study
Soil protection is possible, if the urban planner has information concerning soils developed in the area and their qualities. High quality soils can be kept free from destructive uses. Land uses causing sealing, compaction or contaminations can be switched to areas with lower soil qualities (Heinze, 2000). Hence, soil evaluation can be used to determine alternative locations for specific land uses as well (Heinze, 2000). By considering soils, urban planners do not meet legal demands only. They may gain other positive aspects for their cities, too. Such options include optimal utilization of unused land, reduced sealing, and reduced costs for development of new areas. As case study, a planning area in southwestern Germany was pedologically mapped. The area belongs to a city having approx. 100,000 inhabitants. The city area increases not only due to suburbanization but also due to migration of people since the city is situated close to Stuttgart and Tübingen, which are big cities having universities and good infrastructural connections.
The pedological mapped area covers an area of approx. 7 ha. It dips southwards. The geological substrate consists of Quaternary weathered loams above lower Jurassic marly sediments. The area is situated in a rural environment and is used for agricultural purposes: arable fields, pastures and meadows with scattered fruit trees. In future, it will be used for housing. The mapped data serve as input parameters for the soil evaluation. Its results were considered in the urban planning process.
For the presented soil function “soil as part of the water cycle”, data were used to derive the saturated water conductivity and the available field capacity for each point. The combination of both values deal as input parameter for the evaluation (Lehmann, et al., 2005). The mapping points show different grayish scales according to their evaluation results. Darker gray scales indicate better qualities; white points show soils with lowest marks. Lined areas visualize areas with results above vs. below average. Obviously, high quality soils occur mostly in the southern part (e.g. points 23 to 27). These soils have a high available field capacity but medium permeability. Hence, they perform a good groundwater recharge and filter process. Soils reaching lower marks often consist of compacted material and thus reach low water conductivity values only. The compaction may be caused by the land use, e.g. the use as paddock.
Based on the soil evaluation results, the southern part of the planning area will be used as park or open space. This means on one hand, that no uses which include sealing/ compacting the surface and thus, reducing water infiltration will be established there. During construction works, neither material nor machines should be heavily deposited. A special protection by fencing during construction works may also be an option.
Conclusions
A soil evaluation method developed to deal with urban and natural soils can improve the sustainable development of cities. If the results of the soil evaluation are available to planners, the consideration of soils in the urban planning process is possibly quite easy. The urban planners are not forced to renounce a future land use. They just get information on positive effects of soils on one hand and on the other hand on the loss of soil functions resulting from a certain change of the soil in a negative way. The case study shows, that all planned land uses could be established on the area and no switching to other areas was necessary. The soils maintain their properties and functions as much as possible.
Acknowledgements
The TUSEC-IP Project has received European Regional Development Funding through the INTERREG IIIB Community Initiative.
References
- Außendorf, M., D. Feldhaus, V. Hennings, U. Müller, H. P Schrey, B. Siemer, Th.Vorderbrügge, and A. Wourtsakis. 2003. Methodenkatalog zur Bewertung natürlicher Bodenfunktionen, der Archivfunktion des Bodens, der Gefahr der Entstehung schädlicher Bodenveränderungen sowie der Nutzungsfunktion „Rohstofflagerstätte“ nach BBodSchG. (Catalogue of methods to evaluate natural soil functions, the archive function of the soil, the danger of bad soil modifications as well as the use-function „raw material deposits“ according to German soil protection Act).- Arbeitshefte Boden 2.
- BVB [Bundesverband Boden]. 2000. Bodenschutz in der Bauleitplanung – vorsorgende Bewertung (Soil protection in urban land use planning).- BVB-Materialien Band 6.
- Heinze, A. 2000. Entwicklung und Erprobung eines Verfahrens zur Bodenbewertung und Überblick zum gegenwärtigen rechtlichen Stellenwert des Bodenschutzes. (Development and test of a soil evaluation method and overview concerning the recent legal significance of soil protection) Dissertation. Technische Universität Cottbus, 305 S.
- HLUG [Hessisches Landesamt für Geologie und Umwelt] & Landesamt für Geologie und Bergbau Rheinland Pfalz (Hrsg.). 2004. Projekt zur bodenfunktionsbezogenen Auswertung von Bodenschätzungsdaten in Hessen und Rheinland-Pfalz – Zwischenbericht 2004. (Project to analyze information of the soil estimation concerning soil functions in Hesse and Rhineland-Palatinate- progress report 2004). (http://www.hlug.de/medien/boden/fisbo/bs/index.html)
- Hochfeld, B. 2004. Bodenfunktionsbewertung.- Entwicklung eines Verfahrens zur planerischen Bewertung von Bodenfunktionen in Hamburg unter besonderer Berücksichtigung eines praxisnahen Vergleichs bestehender Methoden. (Evaluation of soil functions.- Development of a method for evaluation of soil function in Hamburg under special consideration of a practical orientated comparison of existing methods.) Dissertation. Hamburger Bodenkundliche Arbeiten, Band 54.
- Lehle, M., J. Bley, E. Mayer, R Veit-Meya, and W. Vogl. 1995. Bewertung von Böden nach ihrer Leistungsfähigkeit. Leitfaden für Planungen und Gestattungsverfahren. - (Evaluation of soils according to their productivity. Guideline for planning and permission proceedings.) Heft 31: Luft, Boden, Abfall. Umweltministerium Baden-Württemberg.
- Lehmann, A., S. David, and K. Stahr (eds.). 2005. Technique of Natural and Anthropogenic Soil Evaluation. (http://www.uni-hohenheim.de/soil)
