Crowded house
The majority of Europeans live and work in cities. Only a hundred years ago, there were no cities with a population of 5 million inhabitants in the world. In the year 2000 there are 60 such cities worldwide. Half of the world's population live in urbanised areas that cover only 0.7% of the total earth surface. But imagine cities at risk of failure of foundations and ground collapse, at risk of landslides or erosion, or regular inundation, or cities sinking away rapidly! Imagine cities short of drinking water and where plants and trees can't grow because of polluted soils, where children cannot play outside because of high natural radiation levels. Urban areas, due to the population density and to the high concentration of infrastructure are extra vulnerable to geological hazards.
Resource consumers
The cities are also the major consumers of mineral resources. Immense volumes of rock, sand and gravel are transported and consumed here. However, without this migration of materials, the cities simply would stop function. In the cities, consumption of products, pollution and exploitation of subsurface take place in the same areas and hence leave traces, such as urban fills. Also, past consumption and pollution has left a legacy of problems. The life cycle of mineral products raise important environmental issues, which can only be solved if geology is taken into account.
Need for subsurface space
In cities, large efforts are made in land modification. But even in already built-over areas, the development of subsurface space is necessary. How would the main cities cope without Metros, subsurface parking lots or road tunnels? Not to mention tunnels for water distribution and sewage management and cable trenches. Constructing this infrastructure without jeopardizing the surface and environment demands knowledge on geological conditions.
The only way to address and solve many urgent problems of urban development is to have relevant geoscientific information organised in GIS and attributed databases available. Many cities (e.g. Moscow, Helsinki, Warsaw) already have specially prepared sets of geological maps, which are used as part of the basis for urban development decisions. (source: http://www.lestari.ukm.my/urbangeology/)
Metro station in Brussels. Photo: R.Dahl
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