Step-up Conference 'MEGACITIES 2000'
Netherlands Architecture Institute Rotterdam, May 12, 1995

report by René Boomkens

Nowadays, the city no longer plays the role of a positive combination of powers for the development of trade, industry, science, etc. Its role treatens to turn into the opposite. In the end, the decay of our culture will be the result. The members of the IAA don't expect this study to have the same result as CIAM's The Charter of Athens. The problems in the megacities have grown too complicated. The investigations are complex and demand an interdiciplinairy approach. Hoogstad pleads not only for more scientific research but also for a better integration of the different sciences which study the problems of megacities.

According to Dr. S. Piët (Chairman of the day) the aim of this day is to make an inventory of what one knows and experiences from the diversity of input. She pleads for patience, that means for a state of orientation on the basis of intuition, knowledge, interchange of opinion and scientific data and heuristics. The first speaker she introduces is

Professor M. Sanglier (senior researcher Instituts Internationaux de Physique et de Chimie). She lectures on the applications to intra-urban models of integrated nonlinear dynamic approach of socioeconomic complex systems. Sanglier characterizes the methodology of their work as building an integrated framework. The framework consists of pluridisciplinary components, non-linear dynamics, historical dimensions, behavioral aspects, micro - macro levels and spatial or geostrategic dimensions. Their aim is to develop tools for a better understanding of the mechanism which induces the evolution of the complex system and tools for helping and analyzing the decision-making process.

The study of non-equilibrium systems gives a new scientific basis for understanding human systems and the origin of their complexity and subtlety. Social systems are by nature dynamic and irreversible. They are dynamic because the components of the system are perpetually changing in time and irreversible because, when an action has been taken the system will adapt the structure to it, and a return to the previous one, even after reversing the original action, is unlikely and impossible. The self-organizing paradigm allows to integrate the notion of history in the dynamics of complex systems. History must be understood as the mechanism which transforms a single past into possible futures. In the behavioral approach one tries to explicitly consider perceptions, strategies and decisions of the actors and their impact on the dynamics of the system.

After explaining the methodology Sanglier shows applications of the model. She shows different simulations of the evolution of a city resembling Brussels. The first model expresses the changes induced in these densities by the mutual interaction of the actors through their conflicting or complementary criteria. In this model they have considered seven variables consisting of five types of employment and two types of resident. The types of employment are heavy industry, light industry, exporting tertiary, infrequent specialized tertiary and elementary tertiary. The types of population are blue collar and white collar. In the simulated city two transportation networks are created, a road network and a set of four public transport networks, describing the possibilities of travel by train, bus, metro and tram.

Over some 40 or 50 years the urban system will evolve to a complex interlocked structure of mutually dependent concentrations. There are two poles of heavy industry, and a distribution of blue collar residents reflecting this. Light industry, after remaining diffuse for some time, concentrates in one pole in the north-east. Financial and business employment in the city centre, at a certain moment begins to spread through the urban space. Then, it exceeds a threshold at a point adjacent to the centre and grows dramatically there, causing the decentralized locations throughout the city to decrease. The white collar and blue collar residents spread out, many live outside the system, according to the accessibilities of the networks, and a spatial hierarchy of shopping centres appears, serving the suburban population and encouraging further urban sprawl.

The ideas sketched out tell us that the deterministic equations governing the average behaviour of the elements of a complex system are in fact insufficient to determine precisely the state of the system. The intervention of humans can decide, at times and places when it is possible. In other words, choice in planning, policy and interventions really exists. However, it is necessary to know the consequences of a plan, a policy or an intervention, and to know in addition, those of other plans, policies and interventions. There must always be comparisons in as many dimensions as possible. Such comparisons are possible in their approach. Sanglier illustrates different types of urban decisions which can be explored in an evolutionary context of possibly changing spatial organization and travel patterns.

The city that evolves in a second model is totally different from that of the first simulation. Industry is dispersed throughout the urban area and with it the blue collar residents and local industry. White collar residents aggregate along the line of hills which have replaced the canal. The distances travelled to work are not the same as before, nor are the costs of shopping trips or the distribution of retail centres. Furthermore, not only are the spatial distributions of the variables different, the global quantities of industrial and tertiary activity, and of white and blue collar residents are modified also. In fact this is true for all simulations, but in this case it is striking because none of the parameters are different, only the terrain has changed.

The model has been successfully applied by geographers to French cities, namely: Rouan, Bordeaux, Strassbourg and Nantes. They have reproduced the evolution between 1975 and 1985 of the different types of economic activities and residents for the different cities.

Sanglier concludes with the following remarks.
-In their models of human systems based on the concepts emerging from the study of dissipative structures in physics and chemistry, they adopt a new approach to the question of anticipating the future, and evaluating policies.
-Their model provides a set of dynamic relationships which can be used to explore many possible futures and alternative structures which could evolve as a result of various pertubations and shocks which it may experience.
-Their new view of the importance of stochasticity, uncertainty and adaption in the evolutionary process suggests that in a very broad range of contexts, long time survival may be related to the presence of stochasticity in a system.

Piët finds it fascinating to see how structure emerges if there is input into this self-organizing system and calls it inspiring if one considers the Megacity as a complex and open system.
Audience: You showed examples of organized civilization. Did you try to apply this model to Third World problems?

Sanglier: Yes, a colleague of mine applied this model to Senegal, but it was more an interregion than an urban application. We also applied the model for energy study in Hoofddorp, The Netherlands.
Audience: I assume that you can also apply the model to issues like scarcity of land, water resources etc.?
Sanglier: Yes, the colleague who worked on Senegal has looked at this problem. I did not work on it. For Senegal water resources are very important and in that model he has tried to integrate more ecological and agricultural problems into the urban development.
Ir. S. Buys (Urban Planner RPD / secretary Megacities foudation), the next speaker, states that very often the reaction to rapid urban growth is negative. He gives the example of Djakarta. Greater Djakarta has now 17 million inhabitants and it will develop in the next twenty years into something like thirty million inhabitants and one often gets the reaction: "Oh, how terrible, this kind of urban development". Governments respond like this and also social and religious leaders, planners and donor agencies. Dutch urban planning has always been in favour of decentralized patterns of small and medium-sized towns. The Dutch development cooperation still has a tendency to concentrate on rural development. In developing countries one sees the same negative reaction to urban growth. Governments are reluctant to improve urban conditions: otherwise even more immigrants would be attracted.

However, no government can stop urban migration. To try to do so is harmful to the city and its population. Moreover, the countryside does not offer an alternative. Rural areas offer no other economic basis than agriculture. They lack infrastructure, skilled labour, producer services and access to government agencies. But, agriculture already stands at maximum sustainable productivity. So continued rural population growth can only lead to ecological disaster. A restriction of urban population growth is not a sensible policy. Growth has to be accepted and accomodated as best as possible.

The challenge to governments, planners and donor agencies is to make unlimited urban growth sustainable on the economic, social, administrative and environmental levels. 'Sustainable' in an economic sense means sufficient industrial and services production to purchase food on the national or world market, also a permanent improvement of the educational level and continuous development of urban infrastructure. 'Sustainable' in a social sence means smooth absorption of rural immigrants. Furthermore, a balance is needed between positive and negative consequences of urban freedom and acceptable densities must not be exceeded. 'Sustainable' in an administrative sense means urban autonomy and an open urban government that is democratic and decentralized and also a cooperative balance between public and private sector and a fair government share in increasing land and property value as results from public infrastructure investment. Finally, in the normal environmental sense 'sustainable' means not exceeding carrying capacity as related to natural factors and to available infrastructure and means careful zoning, a clear structure, sufficient open space and a strong identity and also closed systems to process and recycle urban waste.

Megacities 2000 wants to take up the challenge. Much material is already available, but this does not always reach people in the field, nor is there sufficient exchange among people in the field. Megacities 2000 will establish a CODEX with two parts: a 'library' and a 'network'. In the 'library' Megacities 2000 will make selected existing material accessible and will provide relevant new material. On the 'network' Megacities 2000 will stimulate and organize an easy exchange between workers in the field, scientists and consultants.

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