Humanity has crossed the line from being a rural to urban species since 2007. For the first time in history, more people live in cities and urban areas than in the countryside. Starting in the developed nations, where the urbanisation process has been significantly decelerated in the meantime, urbanisation has especially increased in Asia and South America as well as in Africa to a substantial extent in the second half of the last century. The vast dynamic in these countries is documented by the fact that only three cities with more than four million inhabitants have been in the countries of the developing nations in the 1950s. Nowadays, there are already 28 megacities in these countries. Due to the “functional primacy” megacities do appeal an enormous attractiveness to people and thus mostly become centers of immigration.
Interaction With Water Resources
Processes of urbanisation have a negative influence on the availability and quality of water resources. Especially in developing and emerging countries, the hydrological and hydrogeological setting of each region is deteriorated through the growing urbanization processes. Often the hydrological and hydrogeological basis of an area is strongly affected by processes of urbanisation in these countries. Changes of the structure of urban development going along with the urbanisation will not be without consequences for the environment and water resources (Wehrhahn et al. 2008). Urbanization and the attended changes in the settlement and land use structure, which in these countries often take place under informal conditions, will eventually lead to negative consequences for the environment as well as for the water resources. Consequences for ground water resources are fluctuation of groundwater level and serious pollution of ground water through diverse sources of urban pollutants (Foster et al. 1993; Morris et al. 1994; Vasquez-Sune et al. 2005). Especially in developing and threshold countries, but also in industrialised countries, the so-called urban regeneration of ground water conditioned by canal leakage and/ or missing sanitation systems lead to a strong contamination of ground water (Morris et al. 1994; Lerner & Barrett 1996; Chilton 1999; Putra 2007). Furthermore, urban systems often exhibit a fast feedback between wastewater, surface water and ground water (Azzam et al. 2009). In this context, one of the key tasks of sustainable and long-term land and natural resources management is to optimize water resources utilization referring to the spatial distribution of people and their activities.
In frame of this background the Department of Engineering Geology and Hydrogeology of the RWTH Aachen University analysis in two projects the interaction between high speed urbanisation/mega-urbansation and water resources.
Within the scope of German Research Foundation priority program 1233 “Megacities: Informal dynamics of global change” the Department of Engineering Geology and Hydrogeology of RWTH Aachen University investigates together with other partners on the influences of formal and informal dynamics in megacities by means of the medium water using the example of the south Chinese city Guangzhou with respectively 11 million inhabitants. Within the context of this project a method is being developed and tested that permits complex and highly dynamic urban agglomeration centres as megacities to be foreseeable and controllable. This method is examined by means of flow of material and resources of the reference medium water. The aim is to formulate a conclusion on the quality and quantity of the resource water and by that achieve on one hand the improvement of water supply and express on the other hand a proposal for an effective protection of the resource water in mega-urban centres. Different levels of consideration constitute a high challenge in complex aggregations of mega-urban centres. The examination of the whole area or the mostly large administrative units do not provide a differentiated image, while the complexity on the smallest level – for example single buildings, is not controllable anymore. For the understanding of the system of mega-urban centres it is hence necessary to classify the large agglomeration areas in smaller units. For that reason repetitive micro structures, such as single types of buildings and their contiguous surface broachings, will be merged into groups with respectively uniform and homogenous characteristics.
In India the group studies the interaction of urbanization and water resources. Some methods which are proofed in the China-Project are transferred to the India-Project e.g. land use analyzes by micro scale analyzes, satellite image analyzes etc. In frame of the project the research focus lies in three research areas: Varanasi, Bhubaneswar and Hyderabad, but mainly in the megacity Hyderabad.
Main aspects of this project are:
- Urban development in India
- Change of life styles and the impacts on water resources
- Informal processes/ informality and the impacts to water resources
- Groundwater recharge in urban areas
- Land use and contamination of water resources, especially ground water resources
- Pollution transport modelling
- Vulnerability modelling
Another point of view is the cultural exchange becuase of this the authors posts both research news in the context of interaction of mega-urbanisation and water resources as well as experiences in daily life in India, China and Germany (PhD candidates and master students from India).
Azzam, R., Baier, K., Neukum, C., Post, C. (2009): Sauberes Trinkwasser für die Zukunft – Grundwasserschutz im Spannungsfeld zwischen Global Change und wachsendem Ressourcenbedarf. Umweltforum der RWTH Aachen – Themenheft Wasser, 72-73.
Chilton, J., (1999), (ed): Groundwater in the urban environment, International Contributions to Hydrogeology Vol. 21, 342 p, IAH, A.A. Balkema, Rotterdam
Foster S.S.D., Morris B.L., and Lawrence A.R. (1993), Effects of Urbanization on groundwater recharge, in Wilkinson, W.B., (ed), Groundwater Problems in Urban Areas, Proceeding of Institution of Civil Engineers, June 1993, London, p. 43 – 63.
Lerner, D.N, and Barret, M.H. (1996): Urban Groundwater Issues in The United Kingdom, Hydrogeology Journal, Vol.4, No.1, p. 80 – 89, Springer-Verlag.
Morris B.L., Lawrence A.R., and Stuart M.E. (1994): The Impact of Urbanization on Groundwater Quality (Project Summary Report), Technical Report WC/94/56, British Geological Survey.
Putra D.P.E. (2007): The Impact of Urbanization on Groundwater Quality. A Case Study in Yogyakarta City – Indonesia. Mitteilungen zur Ingenieurgeologie und Hydrogeology, 96, Aachen.
Vazquez-Sune, S., Sanchez-Vila, X., and Carrera, J. (2005): Introductory review of specific factors influencing urban groundwater, an emerging branch of hydrogeology, with reference to Barcelona, Spain, Hydrogeology Journal, Volume 13, p.522 – 533, Springer-Verlag.
Wehrhahn, R., Bercht, A.L., Krause, C.L., Azzam, R., Kluge, C.L., Strohschön, R., Wiethoff, K., Baier, K. (2008): Urban restructuring and social and water-related vulnerability in mega-cities – the example of the urban village of Xincún, Guangzhou (China). Die Erde. Zeitschrift der Gesellschaft für Erdkunde zu Berlin 139 (3) , 227-249 .