The Metabolic City
Metabolic systems have been extensively studied within a biological context throughout history; however, it is only recently that metabolic systems have been researched and related to different fields. The contribution that a metabolic system – as a model – has on urban development is to ensure that the flow of energy is continuous throughout the system, where all the components that make up the system are interdependent on one another. In other words, the backbone of the city heavily relies on allocating the natural resources that will sustain it from the onset. In modern day planning, there is a lack of consciousness in considering the availability of these natural resources and their significance in dictating the urban development and growth. Ancient cities on the other hand do not seem to have the flaws that modern day cities have; these “evolving” cities grew with respect to functionality and the location of resources. Despite the many paradigms that ancient/evolving cities offer, modern day planners seem to overlook these examples. This project aims to design two scenarios of metabolic urban development placed in two regions with different extreme climatic conditions, using planned cities and evolved cities as case studies to help govern the different elements that make up the cities’ fabric. Different tools and methodologies will also be utilized to help achieve two different scenarios that are based on the same metabolic model.
The first leg of the research is to analyze and understand the qualities that differentiate planned cities from evolving ones. To begin with, the planned city heavily relies on predictability. The planners must predict how many people will populate the city, the simultaneous growth of different sub-centers and in what manner the developers will implement the original plans. However, it is merely impossible for anyone to predict the expected population of a city. The city of Brasilia in Brazil was predicted to accommodate 500,000 people, however it eventually grew to 2 million, which pushed the city limits outside the boundaries of the topography it was originally intended for. When creating a planned city, the planner must also control the rate by which the city grows. In the example of Milton Keynes, in the UK, the simple fact that one shopping center grew faster than the rest had a vast negative effect on the city. Retailers that were spread throughout the city could not sustain themselves, and consequently, a monocentric city was shaped. The analyses of several planned cities lead to a straightforward and vital conclusion; there is not any one street network that can be considered uniform and/or global enough to be applied to any site regardless of topography or climate. The modern consensus is that the gridded street network has become the most efficient one; this is completely false. The single advantage of gridded networks is lack of congestion; due to several routes to any destination, congestion is very rarely an issue; the disadvantage of this is that there are many streets that are very rarely used, hence neighborhoods are left ‘forgotten.’ It is within these neighborhoods that crime is at its peak.
Evolved cities on the other hand are much more culturally rich and have a much more functional street network that is topographically based. Nonetheless, it is difficult to come to a conclusion that is completely preferential towards evolved cities, for the simple fact that evolved cities have become so culturally vibrant because of the different cultures that have settled in them. The overlapping of each cultural settlement from cultures that had a unique identity and set of requirements has given evolved cities their identity. Thus, to simulate an evolved city seems unpractical; to try and replicate a system that has evolved through several millennia is impossible. The logical solution seems to be an optimal balance between planned cities and evolved ones, in other words, ‘”planning” an “evolving” city.’
The density of the city is a factor that must not be overlooked. The major advantage of a dense city is its tendency to be highly energy efficient, however therein lies the possibility of becoming too dense and isolating parts of the city. The proposed models follow the principles of polycentricity to ensure that all parts within the city have easy and proximate access to the central hubs, as well as to break down the city into individual self-sustained patches. These patches grow based on the amount of natural resources provided and the desired density ratio; a new patch emerges as the previous one reaches its “equilibrium” state between resources and population. Integration between agriculture, water resources and the infrastructure within the city is the first step towards emulating a metabolic system.