High-density, mixed-use, complete communities are defined by three key attributes: The first is their density. Although among planners there is no agreed-to definition of what qualifies as high density, the level of density much be that which provides enough dwelling units per hectare to support both a rich mix of retail and commercial at grade, and public transit such as at-grade or underground light rail transit. The second is the mix of uses both horizontally and vertically allowing for residential, commercial, retail, institutional and even some types of industrial uses to be mixed together to provide opportunities for inhabitants to live and work in close proximity. All of these uses are mutually re-enforcing, with high density residential occupancies providing the necessary population support a variety of retail and commercial activities at street level. The third is provision of planning for active transportation including both walking and biking, combined with an effective network of public transit.
High density, mixed-use, complete community planning is an essential ingredient to creating regenerative symbiotic cities. Planning and designing for dense mixed-use urban fabric not only reduces per capita green house gas emissions, but also reduces per capita resource use which in turn reduces the environmental footprint of cities and regional ecosystem degradation caused by low density suburban development.
Indeed, it has been demonstrated by physicist Geoffrey West that as cities grow in size and density their overall per capita metabolic rate (the rate at which a city consumes all resources including energy, water and material resources) decreases exponentially. What does this mean? It means that bigger cities are both more cost effective and greener!
Furthermore, consolidating the urban landscape through high density mixed-use planning is critical to getting people out of their cars and enabling the continued development of active transportation infrastructure and public transit.
Mixed-use densification is best facilitated within a regulatory environment which not only recognizes the tremendous human and environmental costs caused by low-density urban sprawl, but rewards innovative design and efficient use of space and infrastructure.
Planners and urbanists have long argued for the benefits of density, and have clearly demonstrated the health and environmental benefits with hard data. However, many cities continue to under-invest in the necessary infrastructure for density, and have typically failed to develop coherent strategies to finance growth. Density does not always mean towers, and high densities can be achieved with a mix of building typologies at a human scale.
While infill development is increasing the density of many cities, most cities around the world continue to sprawl outwards at low densities. Indeed, changing the current patterns of urban sprawl will be one of the greatest challenges, as well as opportunities of building the Regenerative Symbiotic City.
We must recognize the incredible cultural and economic vibrancy created by dense mixed-use cities, and look for ways to harness this innovative capacity to respond to the challenges of climate change and population growth. Furthermore, enabling public transit and active transportation will be driven by landuse decisions. Effective transit oriented development will be critical to reducing carbon emissions, resource consumption, and the infrastructure required to support electric vehicle use will have to be built into zoning and street planning.
Key Symbiotic City High Density Complete Community Planning Strategies:
- Density high enough to support transit, and transit oriented development.
- Mixed-use zoning with an emphasis on a vibrant, activated streetscape and public realm.
- The incorporation of industrial and manufacturing uses into the urban environment.
- The prioritization of active transportation.
- A built form which is congruent with the local context, both at the neighbourhood and city level.
- Zoning and building codes which allow for greater flexibility and innovation. (For example parking requirements, mix of uses etc.)
Changing the face of urban development patterns will require a new level of community engagement, framed in a real conversation about the necessary changes we will need to make to our urban environment if we are to transform cities into regenerative symbiotic cities. This conversation must recognize both the environmental and human health costs of current low-density development practices and the huge potential benefits associated with the development of high-density, mixed-use, walkable cities. The concept of "market transformation" through incremental change in the regulatory environment could be explored as an option to drive private sector innovation from within the development and construction industry.