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Monday, December 20, 2010


Sustainability begins with instinct and grows to awareness of what is at stake. There are many essential elements of survival, but for me it begins with the land. This essay is about forecasting its capacity to provide shelter in order to preserve the remainder to sustain life. Land supports two worlds and is the platform for city planning, urban design and architecture. If I had chosen another profession I might have debated the choice of land as a point of departure but not its relevance.

From my perspective therefore, sustainability begins with the preservation of land in the garden we have been given. Linnaeus began to organize this garden but overlooked a second world. The built environment was a negligible consideration at the time, but has grown into a competing artificial presence that consumes the land of his work. This is a contest we cannot win in a universe that does not compromise. It is why every acre of land is precious; why we must learn to live within limits; and why we must use each acre wisely within our world as we attempt to shelter growing populations without consuming the face of the planet.

            The consumption of land begins with the concept of property. I won’t even attempt to address this issue except to say that it has been the foundation of perpetual conflict, and that our current legal concepts will either appear anachronistic at some future point in time or become extinct. Adaptation is required and conscious adjustment is not inevitable, but I will leave its legal form for others to debate. My objective is to provide the tools needed to evaluate shelter options within sustainable limits defined by the science of others.

After Apollo 11 most will agree that the Earth is a finite resource protected by a thin film of atmosphere at risk; and that it exists within a universe that has become our definition of infinity. (Visual confirmation that the Earth is round and not infinite was a hard won, but foregone conclusion.) Therefore, the development capacity of land to provide shelter for growing populations becomes an issue of survival, since it is also a source of life that can be consumed. In other words, the built environment competes for land with the natural environment and survival hangs in the balance.

            Land is used by four divisions within the built environment. The Shelter Division is served by the Movement, Open Space and Life Support Divisions. The relationship between building mass, pavement and open space within the buildable area of the Shelter Division is called intensity, which can be magnified by the surrounding intensity of its supporting divisions. Shelter intensity is expressed as the gross building area constructed per acre of buildable land available. Shelter capacity is found when gross building area is multiplied by the population anticipated per 1,000 square feet of building area forecast. The activities sheltered by building intensity combine to establish the social and economic characteristics of urban form.

Intensity options can be predicted with Development Capacity Evaluation software (DCE) based on the forecast model chosen and the values entered in its design specification template, and hundreds can be forecast in the time it takes to sketch one. The evaluation of these predictions can help us learn to use each acre wisely, since I've pointed out that economic potential is a function of the social activity within building intensity; but overdevelopment represents a threat to our health, safety and welfare.

There has been no adequate definition of “overdevelopment”, so the debate has wandered in a forest of detail and emotional confrontation that has only led to annexation, sprawl and blight. Debate has been limited by the language available, and DCE has been written to expand this vocabulary with accurate predictions of building capacity options. This may improve our ability to shelter growing populations within sustainable limits.

The average yield from a buildable acre must at least equal a city’s operating, maintenance, improvement and debt service expense per acre to avoid deferred services and deterioration. Acres must also be preserved for agriculture. The land beyond this built environment suffers our presence at its discretion, and the atmosphere protects us all from a universe of forces we cannot begin to comprehend. This is the ultimate definition of “unstable” and we tamper with its balance using the concept of “property” as justification. These forces do not recognize ownership however. They respond to land use and expect us to recognize and respect the gift we have been given by learning to live within limits based on an understanding of intensity and context.

Intensity and context combine to create neighborhoods, districts, cities and regions. When the equations of intensity embedded in DCE software are linked to the mapping power of geographical information systems (GIS), the three-dimensional potential of urban form will emerge as options expressed in a visual and descriptive language. This can lead us toward life within limits that protect the health, safety and welfare of two worlds that now compete for survival in a competition that is no contest.

Intensity options represent context parameters. If we must learn to live within limits, then both intensity parameters and context design are critical to our health, safety and welfare. Within all divisions of the built environment, context is the form, function, appearance and arrangement of building mass, pavement and open space within the intensity parameters established. The most prominent attempts to establish context parameters have been land use and right-of-way regulations, but their lack of ability to forecast intensity and correlate socio- economic benefit has produced a sprawling attempt to return to the farm.

Context is mute testimony to a great number of tactical design decisions made to achieve strategic leadership objectives. Strategy and tactics are lost without a goal, however. In this case, victory will be defined by shelter within symbiotic limits that protect the survival of all life on Earth with dignity. This is a worthy purpose for our continued presence if we can accept our stewardship responsibilities.

Author Note: Portions of this article were excerpted and edited from the second edition of my book, Land Development Calculations, and its attached forecasting software, Development Capacity Evaluation, v2.0 published by The McGraw-Hill Companies, 2010. The book can be found on

The following articles can be read on my blog, Cities and Design, at

1)             "Replacing Density" discusses its leadership weakness and intensity alternative,
2)             "The Limits of Shelter Capacity" provides expanded detail regarding intensity,
3)             “The City is a Farm” discusses the relationship of intensity to economic development,
4)             "The Disorganized Zoning Ordinance" outlines the legislative confusion that impedes leadership progress,
5)             “Examining Architecture” takes a closer look at a piece of the city design puzzle,
6)             “The Variance Trap” illustrates development regulation weakness with a residential forecast model from the Development Capacity Evaluation (DCE) software collection,
7)             “City Design with Space” discusses the overlooked role of project open space with a non-residential forecast model from the DCE collection,
8)             “The Core of Our Built Environment” identifies the nucleus of development capacity
9)             “Ponzi Schemes and Land Use Plans” offers an alternative to annexation and sprawl.
10)         “Where Does Sustainability Begin?” discusses the importance of land in a competition between our natural and built environments.
11)         “Economic Development Is Missing a Strategy” discusses the intelligence and strategic planning required to identify economic development objectives on the road to a sustainable future.

These articles have been deleted from my blog but are available upon request:

1)             The Concept of City Design” includes an overview and suggested research agenda,
2)             “Politics and Planning” is an argument in support of the effort, and
3)             “Context Measurement” outlines a suggested research yardstick.

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