Problems caused by underdimensioned support systems (transportation, water, power, telecommunications, etc.) in urban areas in developing countries are outlined. Qualitative arguments in favor of the use of the subsurface to relieve the congestion are discussed from social,- environmental, economic and technical viewpoints. Efforts to improve the support systems will, however, not suffice to improve conditions unless land use is controlled. The subsurface should be seen as a valuable resource to be considered in the coordinated, comprehensive planning of land uses and support systems.
The urban population of the world is increasing. Even if projections of the total population of the world today are somewhat lower than they were a few years ago, unanimous projections still indicate a rapidly increasing urban population. The most spectacular increase is projected for the urban population in developing countries, where doubling of the urban population is expected over the next two decades. This will create problems, the solving of which will constitute an enormous task. In developing countries today there are many problems in most urban areas which adversely affect the quality of life. Unless substantial changes in the development process occur, the quality of life in the growing urban areas of the developing world can be expected to deteriorate further. Experience from earlier attempts at ameliorating the conditions is not encouraging. Despite political declarations, professional expertise and not insubstantial resources, the situation in general is not improving. It is against this background that a discussion on the use of the subsurface in urban areas in developing countries should be seen. Incremental measures do not seem to result in the required reasonably rapid improvement of the conditions. In general, it can be stated that the use of the subsurface has not been explicitly considered as a possible resource in the planning for and changes in urban areas. This paper concerns the viability of the use of the subsurface in urban areas in developing countries seen from technical, social and economic viewpoints. The subject has not been studied comprehensively and in the absence of empirical data the discussion must be restricted to qualitative aspects and general observations that may be more or less applicable to different urban areas. It may also be added that these observations are put forward from a planner's point of view.
In order to discuss the viability of subsurface use, let us first look at the characteristics of urban areas in developing countries. These characteristics are very generalized and, accordingly, more or less typical of a given urban area. Historically, many of the larger urban areas, or at least their central parts, were given their basic structure of streets and buildings during the colonial period, even if older patterns may have been incorporated and modifications may have been made later. The densities of these urban areas were fairly low until a few decades ago when the more rapid population increase began to be felt. The technical infrastructure (water supply, sewerage, power, telecommuncations, etc.), to the extent that it was at all available, was often installed at the beginning of this century.