Lamelas Gracia, María Teresa (2007)
Geo-resources and geo-hazards in the context of a sustainable development in the periphery of urban areas, exemplary of a part of the Ebro Basin in the surroundings of Zaragoza (Spain).
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung

Kurzbeschreibung (Abstract)

Although sustainability is a term frequently used in debates on the future of society and its needs (e.g. Agenda 21), many questions seemed to be open with respect to a sustainable management of the Ebro Basin in the surrounding of Zaragoza. This city of about 700.000 inhabitants is located in the central part of the Ebro Basin. This is a highly dynamic economic axis and densely populated area within the Iberian Peninsula. In this sector, the Tertiary playa-lake deposits of Oligocene to Miocene age are only covered, in some areas, by pediments and terraces of the Ebro River and its tributaries. In the periphery of Zaragoza, the interactions with the geosphere have been largely ignored due to the fast economic and urban development of this city. This resulted among others in the destruction of many infrastructures caused by land subsidence, a loss of valuable agricultural land and valuable natural areas and an increasing aquifer contamination. At present, to ensure that land-use decisions imply a high degree of sustainability, it must be taken care of geo-resources and geo-hazards. Therefore, they were regionalised using Geographical Information Systems. In a first step, all available geoscientific data was collected, analysed and prepared for its introduction into a Geographical Information System in order to be mapped (geology, geomorphology, soils, climate, vegetation, land-use, natural protected areas). Afterwards, geo-hazards (erosion, dolines susceptibility and groundwater vulnerability) and geo-resources (sand and gravel deposits, agricultural capability of soils) were detected, described and modelled with the help of Geographical Information System and 3D techniques. The selection of the land evaluation methodologies for geo-hazards and geo-resources modelling was made considering the availability and quality of information for their development, their suitability to the study area and the final objective of the models. The third step aims to develop a GIS-based risk-assessment and decision methodology for sustainable land and resource use decisions (as the title of the project promoted by the German Research Foundation). Here the maps stored in the GIS were combined with multi-criteria evaluation methodologies in order to develop different land-use suitability maps (sand and gravel extraction sites, irrigated land, industrial and urban use). After assigning priorities to individual land uses in case of competing land use interests, areas that are suitable, minor suitable or unsuitable for a special type of land use can be identified. Special attention within this process was put on the groundwater protection and the dolines susceptibility. Moreover the availability of raw materials as sand and gravel was examined. Here the development of a three-dimensional geological model proved to be especially helpful. The regionalisation of the described geo-potentials, their translation into thematic maps and their prioritising using multi-criteria evaluation methods are thereby an important step to a sustainable development, also in the sense of the Agenda 21.

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