BAU386 Symbiotic City

By 2025 Hangzhou is likely to become one of China’s mega-cities with a population of more than 12 million people. The sheer size of the city will stimulate extraordinary economic activity but the available urban planning models seem unable to deliver either highly livable, or environmentally sustainable cities.

A New Model
Symbiotic City is a new planning model which combines nature and the city in a symbiotic relationship of mutual benefit. The model provides a framework for an environmentally sustainable city: minimising energy use and harnessing renewable energy on site; managing and reusing waste on site; producing a portion of the city’s food on site; harvesting, minimising use, and reusing the city’s water on site.

Networked Systems
Symbiotic City is created by laying an urban network over a rural network. The bands that make up the urban networks are never more than 1.6 kilometers wide, while the bands that make up the rural network are never less than 1.6 kilometers wide. This means that even in the centre of the urban band, symbiotic city’s citizens are never more than 800 meters (a ten-minute walk) away from large areas of rural open space offering a diversity of ecological, active, and productive programs. These productive landscapes will contribute to feeding the citizens of symbiotic city and, being close to the population, ensure the CO2 emissions generated by transporting food to the populace are kept to a minimum.

The consequence of the intersection of these continuous networks is that a rhythm of purely urban cells and purely rural cells are interspersed with hybrid cells – cells that are both urban and rural. These hybrid cells can be configured to allow the urban experience to be continuous or the rural experience to be continuous in either direction. These hybrid cells also accommodate a series of eco-corridors that form another network connecting all the purely rural cells. These purely rural cells act as cool sinks within the urban environment, easing the urban island heating effect and cooling the southerly summer winds. They are also a rich source of oxygen located adjacent to the dense urban cells.

Vehicles dominate urban environments because roads are the only continuous systemized surface network in cities. Other systems may at best be tree-like structures, but are only connected to the road network, not directly to each other. Symbiotic city doesn’t privilege the road as the only continuously linked network – the existence of a number of equally important high quality networks ensure the urban environment offers a series of alternative and continuous other ways of experiencing the city. These networks also provide the physical continuity and connection of the various programs of the city’s complex 21st Century economic, social and cultural activity.

Fractal Community Structure
Access to public transport is the basis of the community structure – a 400m radius transport oriented development. At this scale of the city, the community is provided with public transport within a five-minute walk of an urban plaza and public parkland. Each of the transport oriented developments are split into four neighbourhoods (each having a 200m radius) each with their own plaza and parkland. These neighbourhoods are in turn split into four 100m radius mosaics of subculture – smaller scale urban places where the various cultures that exist in the community (the elderly, school children, farmers, youth, etc.) have the opportunity to use the plaza and pocket park regularly. At the larger scale, four of the transport oriented developments combine to become the 1.6 kilometer-wide wide city bands. Again, at this scale, the city is provided with a major urban plaza and parkland. Importantly all these open spaces (both plaza and park) are linked to each other with either the hard or soft networks that run through the city network. They also connect to the rural network.