Methodology for Ecologically Based Landscape Planning
Introduction
How does one evaluate landscape for use in an ecologically sound manner. This document, along with others produced in the 1970s, served as foundation for conceiving and implementing concepts and approaches having since emerged under the term, Sustainable Landscape Design.
In 1974, I was assigned, with Dr. Garrison Evans, as planners for Tompkins County, New York to prepare a report titled, Environmental Image. This document was one part of a Comprehensive Plan Study for Tompkins County. Its purpose was to sketch a pattern for the sound utilization of lands for the growing population of the County.
Although much different in scale, evaluating an area as large as Tompkins County, New York was similar to the methods used to understand forces at work in more intimate landscape spaces. As well, although different techniques were used to gather and record information - aerial photography rather than Google Earth, hand-written and drawn notes taken in the field rather than GPS, hand-prepared Press-Type sheets rather than computer-generated shading patterns - the ability to analyze and synthesize information was no less accurate, if not better understood, by relying on the blend of both left and right brain activities.
The New York State Development Plan of 1971 identified the Ithaca Urban Area as a node demonstrating continuing modest growth. Similarly, two years later, the New York State Department of Transportation designated Tompkins County as one of the state's economic growth nodes, instigating the beginning of active regional planning.
The purpose of Environmental Image was to inform citizens and municipal bodies of Tompkins County about the complex natural and human-modified environment in which we live, so that decisions about development in the County, of whatever scale, could properly reflect the opportunities provided and constraints imposed by the physical environment.
The scale of the assessment was the entire County, an area of 490 square miles (314,300 acres). While designed primarily to inform public policy concerning land use at Town or County-wide scale, the method for evaluating the suitability of land based upon ecologically based planning had value for any piece of land, regardless of size.
Environmental Image presented basic information about the environment in terms of its influence on development, and the impact of development on the natural environment. Carrying out future development of the County in an ecologically sound manner was interpreted to mean avoiding the needless disruption of ecosystems, while helping to balance the value of what was being built with the whole cost to society of building it.
Evaluations were oriented toward long-term development concerns. Our ecologically based evaluation of the natural environment helped determine the capacity of the land to accommodate human activities and facilities. A systemic evaluation of the human-modified environment, specifically utility and other public service facilities, determined where urban-density expansion within and around existing settlements was considered best to occur.
An Ecological Basis for Land Use Planning
A fundamental reason for undertaking an ecologically-based approach for land use planning is that it is generally beneficial - to a wide range of people for a long period of time - to direct future development to areas where expected impact on the total ecosystem is both most favourable and least destructive.
Erroneous assumptions of the past - man and nature are adversaries, nature must be subdued, society of man exists apart from society of nature, man must impose order upon nature, so forth - are best cast aside; they are outdated, unscientific, unsupportable, and potentially dangerous. Human-induced activities of past, present, and future are inescapably part of the total ecosystem, often having considerable effects. According to the current state of scientific knowledge, principles of an ecosystem within which any and all human development and activity takes place, are as follows:
1) Everything affects everything else.
2) All living things are parts of systems composed of physical environmental factors.
3) Factors in each system limit growth, reproduction, or activities of some or all species.
4) Each system has a definite capacity to carry the organisms of the system.
5) Materials are reused in these systems.
6) As specialization develops in a system, diversity increases; as diversity increases, stability of the system increases.
7) All surfaces of the earth in varying stages of development tend towards steady- state equilibrium.
From these governing principles it can be inferred that it is not possible for development to take place and have no impact on the environment. A measurable impact always occurs and continues to be felt throughout the ecosystem. As we examine these principles in light of their meaning to human ecology, we find that more often than not, people have rejected these principles as being not applicable to their lives. Overlooking these principles has precipitated ecological crises of varying magnitude.
It is clear that while past development has had negative impacts, it was not an inescapable condition. Knowledge or concern about ecosystems could have made important differences in the quality of the present environment. Reason suggests, then, that the impact of additional development does not necessarily have to be negative.
It is possible for the physical infrastructure required to support existing and expected population to be developed in such a way that the net impact on the ecosystem is neutral or positive. Benefits to human society by developing harmoniously with the ecosystem have the added benefits of a potentially balanced environment in a steady-state equilibrium.
Building with respect for the natural environment suggests that particular areas are better suited for development than others, while many other areas require precautions or techniques at additional expense to avoid environmental damage. Although these personal and social costs to overcome environmental constraints may be prohibitive, and absolute prohibition to development may be justified, such restriction may not be legally or politically supportable.
Of course - the best opportunity to build harmoniously with the natural environment, at much lower personal and social cost than in less suitable area, is afforded in areas considered ecologically suitable; however, it is possible to build destructively even in the most suitable areas.
Conversely, areas where natural characteristics are unfavourable - shallow bedrock, high water table, poor drainage, soils highly subject to frost heaving, severe erosion susceptibility and steep slopes - constitute a mixture of constraints sufficient to classify a site as unsuitable for development. However, it is also possible to build a better quality development in such an area provided sufficient enough resources are both available and used to overcome apparently formidable natural environmental constraints.
Private and Social Cost
While the decision to expend funds to overcome environmental constraints - deciding whether benefits from the development justify the expense - may be a public and/or private decision, questioning the necessity for precautions is a matter of public interest and subject to public scrutiny.
Seeking a balance between environmental protection and private and/or public development interests makes it necessary to look at both private and social costs for opportunities lost. It cannot be assumed that the cost for making a choice is borne solely by the individual. Because opportunities lost for choices made are often opportunities lost by society, we can assume nearly all choices involve social as well as private costs; opportunities lost are not one's alone.
It is not simply a matter of the right to use your own property any way you wish, as opposed to the ability of government, through the vehicle of environmental regulations, to tell you what you can or cannot do with private property. Keep in mind that costs of development, in large part, are distributed to neighbours and society as a whole.
Social costs, those borne by society as a whole, include: 1) the cost of construction and maintenance, 2) the cost of impact on local and regional ecosystems, 3) the cost to provide public facilities and services, 4) the cost of transporting persons, goods, and services.
With the concept of social cost in hand, it is possible to evaluate all available environmental characteristics and data, and say with some assurance that development in one particular area is expected to result in greater social cost than development in another area.
Cost is not a short-term matter. An ecologically based approach to landscape analysis and planning is viewed in an extended time frame. Because the ecosystem responds in an evolutionary fashion, impacts on the ecosystem must be viewed in the longest time possible.
This provides a basis for directing development into areas considered to be the most suitable for settlement, providing opportunities for new development and accrued benefits, while minimizing social costs and the negative impacts.
Environmental Factors and Methodology Used in Ecologically Sound Planning
The specific purpose of this project was to define and delineate the most suitable areas in Tompkins County for urban and rural habitation. The process is similar to that used to define and delineate the most suitable areas of a landscape for certain uses. An evaluation of anticipated social costs for developing particular locations is based upon the presence of suitable, moderately suitable or unsuitable conditions.
The environment and the developments planned within have a complex relationship; analysis requires referral to an exhaustive list of environmental factors. They each configure, in dependence upon one another, a variety of meaning and interpretations. Consequently, we developed a systematic analysis with each step fully described, evaluations explained and sources identified. Detailed presentation of this method of analysis would enable anyone finding its results questionable to trace through the entire process and find precisely where they disagreed with interpretations, making personal adjustments accordingly.
The range of environmental factors germane to ecologically sound land use planning continues to expand. The primary references used to compile the list were G. Angus Hills' The Ecological Basis for Land Use Planning and Ian McHarg's Design with Nature.
Because of the dynamic relationship among environmental factors, their mere listing have potential to lead to limited understanding and over-simplification. To make as complete an assessment as possible, while keeping in mind the intricate relationships involved, the list of environmental factors directly influencing social costs of settlement was divided into two main components: natural and human-induced.
The natural component was subdivided into fields of natural studies: geology, physiology, pedology, hydrology, flora and fauna. The human-induced component was subdivided into tangible factors that could directly encourage or limit private settlement.
For each physical and human-induced factor, a map was made describing presence, dimension, and quality or quantity of the factor characteristics. Each map was delineated with press-on acetate sheets cut by hand with variations of shading to show the presence or relative severity of the factor characteristics.
The scale with which we were working: 1 inch= 1 mile, (with Soil Conservation Survey Associations Maps, accurate to 25 acres), governed the both the choice and accuracy of the maps of environmental factors. The result was a comprehensive list of environmental factors to meet requirements and purposes of this study
Once environmental factors were collected, recorded, characterized and mapped, there remained the matter of digesting and utilizing the material in light of the objective: defining the most suitable areas for settlement, and determining the manner in which to define the most suitable areas. This definition again was divided into two components: physical compatibility, showing the ability of lands and waters to support settlement, with accrued social benefits, while imposing relatively fewer social costs; and situation suitability, describing direct and tangible human-induced activities that support settlement with accrued social benefits, while imposing relatively fewer social costs.
Physical Compatibility was defined by:
1) Physical factors widely accepted from an engineering perspective to have direct influence upon the cost of structural and utility systems;
2) Factors requiring particular conservation management practices that influence overall suitability and long-term personal and social cost;
3) Fragile natural resources not necessarily compatible with many forms of settlement;
4) Suitability of the land for agriculture, a prime land use not necessarily compatible with many forms of settlement.
Situation Suitability was defined by:
1) Land uses limiting private settlement, such as viable agricultural land and lands under preemptive activity and control (publicly and university-owned lands).
2) Projects that could encourage private settlement, such as historic and cultural resources, improved-access and travel time, and public utility systems.
Transparent maps of relevant environmental factors were overlaid, one on top of the other, on a backlit table. A visually distinct outline of composite factors geographically summarized the influence of each group of factors. Determining importance or significance of one map or factor relative to another posed difficulty with this methodology, for which we sought assistance from experts in the appropriate field of resource analysis.
The final delineation into three types of areas of the county: areas considered most suitable, areas requiring modification at extensive cost, and areas considered unsuitable because of legal restrictions or prohibitive cost - for rural and urban density - became the result of this ecologically based landscape planning procedure.
Having been involved with these activities in the midst of the first contemporary environmental legislation provided an unprecedented and rich opportunity - to be on the ground floor of what today is referred to as sustainable landscape design.
1:2008