Thursday, January 27, 2011

HIDDEN IMPLICATIONS of DESIGN DECISIONS

PLEASE NOTE THAT MY PRIMARY SITE IS NOW LOCATED AT “THE BUILT DOMAIN.NET”. A link is provided in the upper right hand corner of the screen.


            At the present time, many design standards for the built environment serve a specific purpose, remain uncoordinated and have hidden implications. For instance, zoning setback standards have little in common with the separation requirements in a building code, and both are unrelated to the impervious cover percentages used to design storm sewer capacity, but the impervious cover percentage is a controlling factor that affects the other two.

I doubt that many cities have a map that includes the impervious cover percentage used to design each segment of their storm sewer system. This, however, is a critical piece of planning information that is rarely recorded; and when it is, the data rarely leaves the engineering division. Part of this may be due to the history of storm sewer evolution and our reluctance to examine technical engineering detail.

In the beginning, public health was concerned with the construction of sanitary sewers. Storm water was an environmental issue and sanitation was the first priority. Storm water could not be ignored as urban areas grew, however, since increased housing density produced increased runoff; and water is a force that demands respect. The problem was that an ideal sanitary sewer system is a closed system, but a storm sewer system must be open to receive runoff. Budgets are always an issue and compromise produced a combined sewer that was an open system. The result produced street and basement flooding with sanitary effluent when storm runoff exceeded pipe capacity. This was inevitable because storm water cannot be accurately predicted, and increased pipe sizes increase construction cost. The conflict was addressed by separating the systems at great expense, but combined sewers remain in many older cities and storm water capacity can still be exceeded.

Combined sewers are now unacceptable, but storm water remains unpredictable. Municipal budgets have increased to accommodate separate sewer systems, but budgets have unwittingly limited the size of storm sewer pipes. (Sanitary sewers require smaller pipe sizes and the capacity required is easier to predict.) We are now recognizing that storm water is an environmental problem that also constitutes a public health issue; and that expanding populations require additional shelter that increases runoff. In other words, storm water is not clean water discharging into our natural water supply. It needs sanitary treatment that represents another unanticipated public expense and the demand is increasing.  

            Behind all this detail is a critical engineering design decision. There are a number of factors that lead to the definition of a storm sewer system, but the amount of impervious cover anticipated should stand out to city planners and political decision-makers. For instance, an engineering consultant may use 30% impervious cover and a 100 year storm as sewer design criteria; but if this knowledge is unrecorded or limited to the engineering division there is a coordination problem. The 30% standard may be adopted to hold down pipe size and construction cost, but the decision means that everyone served by the line should pave and build on no more that 30% of his or her property. In other words, 70% open space is required. If the 30% allocation is exceeded by one property owner, the average allocation is reduced for all others who share the system, if its capacity is to be protected. This rarely happens for a number of reasons, including requests to vary from zoning regulations that are uncoordinated with the open space decision.

            I think it’s safe to say that zoning setback lines and building code separation requirements are not coordinated with the impervious cover limits adopted by storm sewer design engineers. In fact, these decisions are rarely recorded on storm system maps that have evolved over time. This means that building plan review and variance application requests can be unwittingly permitted to exceed storm sewer design capacity. Flooding is an inevitable long-term outcome if coordination is ignored, and we are slowly recognizing that this is a public health problem as well as an environmental threat that grows with the population served.

            Wherever storm sewers exist an open space decision has been made. This may not be apparent, but sewer capacity based on a 30% impervious cover assumption means that 70% open space is required. Many, if not most, of these decisions have been lost in time however, and can only be recaptured by reverse engineering the design. This places every system with an unknown open space value at risk of overdevelopment. In other words, wherever a storm sewer system is added or extended, an open space decision is made that directly affects the development capacity of the land involved, but many will never be aware of the limitation and continue to believe that there is an inalienable right to fully develop the property.

I should note that a 30% impervious cover limit can be a residential subdivision feature that may be inadequate to serve future requests for expansion when the total lot area is too small. When this is the case, the threat of overdevelopment increases as variance requests appear and the limit is unknown. The answer is to be aware of the relationships that require coordination and be prepared to explain their implications; since a tight budget means smaller infrastructure and limited building development capacity. These are leadership decisions that a city must live with for a very long time. They restrict its economic development potential and are a recipe for sprawl that has even greater consequences.

            The extension of sewers does not control growth. It encourages sprawl because the potential yield per acre is unknown, and can be an asset or liability to a city’s future economic health. It represents new money but can become a very old burden under these circumstances. This is not economic development. It is economic roulette with little concept of the odds involved. The only apparent solution is to plan with a grasp of land development capacity, a concept of the potential yield per acre from various land use activities, and projections of current and future government expense per acre. The result will be a plan in three dimensions, called urban form, which is capable of producing the yield needed to support a community’s average expense per acre over an extended period of time. Only then can cities extend sewers with the capacity and vision needed to live well within environmental limits imposed by a power we cannot challenge.

            The capacity of a storm sewer therefore is a function of the planning design decisions adopted. The rest is technical calculation, contract document preparation, bidding and construction execution. The difference between leadership and management in this sequence should be apparent, but leadership has been confused because essential goals, strategy and supporting intelligence have been missing. (I’ve previously mentioned that in my opinion the goal is to learn to live within limits and strategy must be based on an understanding of the physical, social and economic implications of land development capacity.) At the present time our efforts have produced a cancer of sprawl. This has happened in the name of freedom because the continent and planet appeared infinite, but a new level of awareness has arrived. The unlimited consumption of land in the name of freedom is not democracy. It is a threat to the people and the planet. The solution is to think in the three dimensions of urban form, with the intelligence needed to forecast and evaluate its physical, social and economic implications. Only this will produce the credibility and vision needed to lead private development toward the public goal of a sustainable future, and engineering systems to support this effort.

Author Note: In the preceding example, if 70% open space were required by the storm sewer system in place, the land development capacity of the remaining 30% could be predicted by choosing a forecast model from the Development Capacity Evaluation (DCE) software collection. (In fact, any percentage can be evaluated.) I’ve discussed this potential in previous essays and won’t repeat myself, except to note that the software and textbook are noted in the author profile.


Other Hidden Implications of Design Decisions

For those who have not read, "The Variance Trap", I would like to mention that it explains how overdevelopment is inadvertently encouraged by zoning regulations that are not anchored by an understanding of land development capacity. "City Design with Space" expands on the discussion.

Sunday, January 9, 2011

THE NEXT LEVEL OF AWARENESS

            Richard, you and David are confusing what city planning is attempting to do with its current capability. There is no question that its tactics are inadequate and its strategy is confused. Its two-dimensional goal to separate building hazard and incompatible land use activity is also changing. It is recognizing that cities are three-dimensional artificial environments that are sprawling without restraint across the face of the planet. Satellite photography has made it very apparent that they consume the land of their dominant partner and have not learned to live within limits. As a result, they have not struck a sustainable balance with the natural environment and ecology of the Earth, nor have they resolved their physical, social and economic deficiencies.

            City planning must become city design in order to establish a sustainable relationship between the competing worlds of the natural and built environments. A strategy will be derived from an evaluation of development capacity options and implications, since the goal is to shelter and serve populations within sustainable geographic limits that protect all life on Earth. The tactics of architectural design will produce a response one project at a time, but tactics without a goal and strategy produce random battles across the landscape. The result is many casualties and little progress.

In the end this is about people and the shelter, movement, open space and life support they build; since these divisions of the built environment consume the resources of their natural partner and pollute what remains. Our success in constructing a sustainable presence will be expressed by the nature of this evolving urban form, since it will illustrate our success in learning to live within limits. Architects are among those qualified to consider this question, but they must think outside the box they design while improving its efficiency.

City design will depend on our ability to quickly and accurately forecast development capacity options, since life within limits requires an ability to wisely use every acre we consume to shelter and serve the activities of growing populations. I can think of no greater challenge to the family of man, even though others may be equal. Architects and many other professions must be willing to step into the public arena using a common language of development capacity evaluation -- if they wish to contribute to the strategy required. Independent tactics will not bring us to the next level of awareness -- that a new goal for survival is needed.

I have already exceeded the limits of a brief comment. If you wish to read more, please visit my blog at http://wmhosack.blogspot.com/ where the following articles can be found.

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.

Tuesday, January 4, 2011

STRATEGY IS MISSING FROM ECONOMIC DEVELOPMENT

PLEASE NOTE THAT MY PRIMARY SITE IS NOW LOCATED AT “THE BUILT DOMAIN.NET”. A link is provided in the upper right hand corner of the screen.


            There is a solution to the economic problems of every state and local government, but it requires a new approach to city planning and design that must be built from currently scattered information; and it can take us well beyond the simplistic concept of a balanced annual budget.

Attracting new business to finance past practice is not economic development. It is another Ponzi scheme built on the best of intentions. New revenue is considered a budget solution even though the income per acre may not equal or exceed the jurisdiction’s average annual expense per acre, especially when forecast over time. This lack of planning consideration for the relationships among land development capacity, land use activity and economic yield per acre is the driving force behind the annexation and blight of American cities as they sprawl in a futile search for economic stability.

All residential and commercial land use activities do not produce equal revenue per acre and many do not meet a jurisdiction’s average annual expense per acre. Unfortunately, we do not know the average yield associated with each activity group; and a city’s average expense per acre is simple division but rarely calculated as a planning benchmark for city design and economic development. As a result, economic development is pursued to balance annual budgets without a strategic plan for greater success. This will continue until our plans correlate development capacity options with land use activity and revenue potential.

In military terms, economic development is a tactic employed to achieve an objective. An objective should be part of a strategic plan designed to achieve a greater goal. When the goal is debated and strategy is missing however, tactics support random battles that wander across the landscape. In this case, a strategy to achieve economic stability within physical limits that protect the agriculture, environment and ecology beyond is missing; and it can only be expressed with plans for urban form that adequately shelter activities, improve our quality of life and yield the income needed to meet public expense over time. This expense is a constant source of debate that distracts us from the primary goal. There is a way to address this political problem, but it will remain a subject for another time.

I have tried to focus this message and hope I have made it clear that city and state plans for land use and urban form will directly affect our social and economic welfare. They will also determine the land that will remain to sustain all life on the planet, but the data (intelligence) required to support these plans remains uncollected. In other words, the goal is clear but a strategy has not been filtered from intelligence to lead the power and tactics of economic development toward victory.

The march will begin when we are able to quickly and accurately forecast development capacity options and implications for every acre of land we consume, since a sustainable future will depend on the balance we create between the natural environment of our host and the artificial environment of our presence.

Forecasting is now possible with Development Capacity Evaluation software, but the values entered in its design specification templates produce forecasts with implications that remain to be evaluated. Context evaluation of existing projects with similar values, however, can provide the intelligence required to create economic development strategies with plans and language that can lead us to our goal.


Author Note: Development Capacity Evaluation software is attached to Land Development Calculations, second edition, McGraw-Hill, 2010. Chapter 6 expands on the observations above and is entitled, “Land Use Allocation and Economic Stability”. The book can be found on Amazon.com. The first edition was published in 2001 and translated by China in 2007.
 

The following articles can be read on my blog, Cities and Design. The third article is an expansion of the discussion above. The blog can be found at http://wmhosack.blogspot.com/:

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 the 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 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.