An interesting pair of statistics is that while less than five per cent of the surface of the Earth is developed at an urban density, Canada, with a vast landmass, is a particularly urbanized country, with somewhere around 90 per cent of its population living in cities. It’s pretty clear that there is a lot of space out there. Why, then, is density an issue?
For much of the world, the main urban problem is overcrowding. However, most North American cities, Calgary included, seem to be suffering from the opposite problem — not enough concentration of people to economically provide the required services and amenities, such as schools and LRT, and to produce the vibrancy that most people are attracted to. Calgary’s most current planning documents advocate increasing density, and indeed many urbanists view density as the magic bullet that will cure all our social ills, including sprawl, homogeneity of suburbia, decline in walkability, shortage of good public spaces, and even homelessness. But is it that easy? The concept is often politicized, idealized and also aestheticized, but what exactly is “density?”
Density, as a measure, represents the relationship between a given land area and the number of either people who inhabit that area (persons per acre or hectare, or ppa/pph), or the number of dwelling units in that area (upa/uph). Density is also sometimes expressed as persons per unit (ppu). While planners and urban designers have no influence over persons per unit, units per acre is directly a function of planning and development decisions, and the notions of what is acceptable and desirable density have changed over time along with planning thinking.
In the industrial urban conditions of the late 19th and early 20th centuries, density was rightly perceived as a highly negative quality — the crowded and unhealthy inner-city areas are well documented by everyone from 19th century novelist Charles Dickens to legendary Toronto-based urban critic and author Jane Jacobs. The push in most of the 20th century was to reduce urban density and provide residents with space, clean air and a house of their own. Most city plans, Calgary’s included, specified maximum densities, and one of the predicable results was the spread of low-density (i.e. 6 - 10 units per acre) suburbs filled with single family houses. Most new housing now automatically takes this form, while at the same time, it is now well understood that those low densities make it almost impossible to build a city that provides, economically, the basic essentials of water, sewer, power and public transit. Those low densities are also a major impediment to ensuring that schools, swimming pools, libraries, and stores will be within walking distance of every resident, because all of those services and amenities depend on having enough people within their catchment area. For example, a bookstore generally requires a population of at least 15,000, but that is seven to eight times the population that lives within walking distance of a typical neighbourhood shopping centre.
There is clearly a gap, however higher densities are more difficult for Western culture to wrap the mind around and accept, especially in the wide-open spaces of Alberta. Although all five boroughs of New York can be contained in the land footprint of Calgary, Manhattan densities are shocking to all but a handful of Calgarians. So, typically, the addition of higher-density developments in any established area usually provokes NIMBY (not in my backyard) reactions.
This is a big issue, but the problem is not one of simply discovering the magic density figure, or of trying to change peoples’ perceptions. How can higher densities lead to better intensity and vitality, so that it is clear that having more people in an area will actually improve urban quality? What are some higher density building forms (and not just residential towers) that would be appropriate for the established neighbourhoods of Calgary? What is the block pattern that works best with higher numbers of people? What is the best organization of density? Should it be dispersed, or concentrated along certain thoroughfares? What are the other elements of the urban structure (e.g. trees, sidewalks) that need to be included to produce a high quality environment?
City planning and urban design need to consider the issue of density in the kind of comprehensive way that can address all of those questions and more, as it is unproductive, and also impractical, to just have a yes/no approach to increasing density.
Click here for the full article by Professor Sandalack in the Calgary Herald.