To cite this abstract / Pentru a cita rezumatul:
Petrisor AI (1997), Models for Sustainable Development of the Cities [in Romanian], BS Thesis, UNESCO Cousteau Chair of Systems Ecology and Environmental Management, Faculty of Biology, University of Bucharest, Bucharest, Romania, 133 pp.



Alexandru-Ionut Petrisor

Submitted in Partial Fulfillment of the Requirements

for the Degree of Bachelor of Science in the

UNESCO-Cousteau Department of Systems Ecology and Environmental Management

Faculty of Biology

University of Bucharest

July 1997



A correct understanding of the concept of "sustainable development" involves an analysis of the development of the human socioeconomic system in its historical perspective. This process is analog to ecological succession, but, differently, is dictated by economic and social laws. The engine is the exponential dynamic of human population, and, correlated with this, the exponential dynamic of the needs of humans.
In a first step, human populations were integrated in natural communities, and the man felt himself as a part of the environment.
When industrialization started, humanity passed to a new step - the "divorce" between man and nature, ending in the 70's with the energy crisis. Human society realized at this point that uncontrolled development is joined by phenomena as:
* Overexploitation of the resources of the natural capital
* Pollution
* Loss of biodiversity
* Fragmentation of habitats
* Introduction of new species
* Genetic manipulation
* Execution of large constructions on fresh waters (such as dams etc.)
united under the common name of "environmental deterioration".
At this point, an unrealistic solution was proposed: preservation of the natural capital , opposed to the development of the human society. The solution to this apparent conflict was sustainable development, marking a new step, the era of the reconciliation between man and nature.
Theoretically, sustainable development is the development that satisfies the needs of the actual generation without compromising the chances of the future generations to satisfy their needs in the same manner, and in practice it involves the integration of environmental protection regulations in the policies and strategies for development.
The implementation of the sustainable development solution assumes the elaboration of models for sustainable development. This involves a holistic approach to the problems, is based on public participation and includes ecological reconstruction.
The problem of sustainable development represents a real problem, and, at the same time, a priority, proved by the large number of papers on this topic, and the amplitude of workshops, conferences, symposia and other similar meetings on this matter.


The elaboration of models for the sustainable development of cities involves approaching the cities as ecosystems. This approach led to the apparition of a new branch of systemic ecology: the urban ecology .
The essential difference between urban and natural ecosystems is represented by the presence of the human species as a dominant species in the first case; the other differences represent, in fact, consequences of it.
Urban biotope includes stationary and man-generated elements (last being generated throughout human activities). The first category includes geographical, hydrological, geological, and soil-related elements. However, each of them differs through a series of parameters by its homologous in a natural ecosystem, as a consequence of human actions. Man-generated elements are produced as well by the urban structures and by human activities. Urban structures reflect the satisfaction of some human needs, of a biological nature, related to socioeconomic organization and purely economic. Human activities generate different aspects of environmental deterioration, the most well-known one being pollution, manifested at the level of atmosphere, water, and soil.
The organization of urban communities is based on ecological niches, spatial or food-related. Vegetal communities are subject to the modeling action of the man, being found especially as green spaces or urban forests. Animal communities are poorer, being represented especially by eusynantropic species.
From the common features viewpoint, urban ecosystems have a lesser diversity compared with natural ecosystems; functionally, it is concretized in a lesser self-regulatory capacity, a reduced stability and dependence on human actions. Moreover, biological laws act differently in these ecosystems, and socioeconomic laws are predominant.
With respect to the functions of ecosystems, essential differences appear. Urban ecosystems are energetic parasites on natural ecosystems, bio-geo-chemical circuits tend to become linear, and stability decreases. Furthermore, urban ecosystems have new functions, related to their socioeconomic specific.
From a historical perspective, the impact on the environment increased gradually since the very beginning of humanity until nowadays. At the same time, people started thinking over the elaboration of the model for the city of the future. After a series of sectional essays, in the United States of America a holistic model was elaborated to account for the legislative frame, theoretical base of systemic ecology, economic frame, accumulated experience, and participation of the public, specialists, and decisional factors. Meanwhile, this model resolves the problem of energy management, and controls the flux of urban wastes, liquid or solid.
The national legislative, administrative and institutional frames in this field rely on national legislation, built on the universal principles of environmental legislation. It comprises regulations for environmental protection ( Constitution, Law of Environmental Protection ) and for other legislative fields (related to activities inherent to the development of cities: General Regulatory of Urbanism , Law of Urbanism and Urban Planning ). At the international level, the most important documents in this field are the Convention on Biological Diversity , Chart of Torremolinos , and Agenda 21 . The responsibility belongs in our country to the Ministry of Waters, Forests, and Environmental Protection , and to the Ministry of Public Works and Urban Planning , and at the international level to the Organization of the United Nations , through its programs.
A first category comprises models elaborated by urban planners. Historically, there can be distinguished pre-urban and urban models.
The main pre-urban models are:
* Progressive model, focused on the needs of humans
* Cultural model, based on the needs of human communities None of these models offers a satisfactory solution with respect to the impacts on the environment. Urban models are:
* New progressive model, that promotes the functional city
* New cultural model, similar to the previous one
* Naturalist model, corresponding to organic architecture. The naturalist model and, somewhat, the new cultural model decrease substantially the impacts on the environment, even though they are the result of a sectional approach.
* "Technotopia" promotes the model of the technical city, involving a complete elimination of the natural ecosystems;
* "Anthropopolis" accounts mainly for the needs of humans, involving public participation.
All the urban models represent the result of a sectional and anthropocentric approach.
Economic models involve performing an impact study for each proposed model for the development of the city. Problems are related to the identifying all components and assigning a market value to environmental goods and services.
Mathematical models are synthetic models, resulting from a holistic approach; they assume the participation of a team of specialists, and approach mostly the holistic model for the development of cities.



The development of Hunedoara County, that includes Petrosani conurbation, is mostly related to the development of mining activities and, during our century, to the development of various industrial sectors. The landscape is predominantly mountainous, and the clime supports western influences. The vegetation follows the levels of the landscape and clime, and the fauna corresponds to different vegetal associations.
The main problems at the county level relate to population increase and its consequences, manifested mainly though the overexploitation of natural resources, and pollution. Environmental protection regulations are sporadic and result from a sectional approach.
Petrosani conurbation appeared as a city in the period of mining industry development. From the biotope and community viewpoint, it lies in the range characteristic to Hunedoara County. A particular aspect is represented by the insufficient reserves of water.
The main problems at the level of Petrosani conurbation are related to the elevated pollution, degradation of lands, supply of water and energy reserves, unwise management of urban and industrial wastes, and economic problems, related to the specific of the area and to the transition period crossed by the Romanian economy in general.


The only model currently elaborated is the urban model proposed by the National Institute for Research and Development for Urbanism and Environmental Planning ( URBANPROIECT ). The model is focused on the satisfaction of human community needs (biological, social, and spiritual needs), and proposes three major strategic objectives:
* 1 . Optimal living condition for everybody - year 2020
* 2 . An ecological city - year 2093
* 3 . A sustainable city - undetermined period.
An economic model does not exist yet, but economic criteria can be presented to constitute the base of a possible model, through the analysis of existent problems and possible solutions. All these problems are related to the increased density of the population in Petrosani area and refer to:
* Waste management
* Water resources supply
* Misuse of lands
* Structure of productive activities and services
* Elevated consumption of energy
* Maintaining the autochthon population
* Increased impact on the environment.
Based on the economic and urban models for the development of Petrosani conurbation, a mathematical model could be elaborated to establish the optimum of a Lagrange function for consumer's utility.


1. In the conditions where the only chance for the survival of human socioeconomic system is the implementation of the sustainable development solution, the elaboration of models for sustainable development represents a real problem and a priority as well.
2 . An analysis of the theoretical base existent in the field reveals the presence of sectional approaches; this is why the only solution is to implement the sustainable development solution.
3 . This approach involves approaching cities as ecological systems and identifying them according to the system model.
4 . A comparison between urban and natural ecosystems evidences the existence of essential structural and functional differences between them, as a result of the presence of the human species as a dominant species in the first case.
5 . The urban, economic, or mathematical models already elaborated, even if they represent the result of a sectional approach, can offer criteria necessary to construct a holistic model for the sustainable development of cities.
6 . An analysis of the case of Petrosani conurbation proves that there are premises in our country to implement the solution of sustainable development in the activities related to the development of cities.
7 . An analysis of the theoretical base, proving the existence of uncertainties and lacks, sustains the necessity to develop the knowledge in the field of sustainable development of cities.