A review of theoretical approaches related to the reuse of urban gray and brown lands and its impact on sustainable urban development

In many cities, abandoned and barren lands are exploited for a new form and function; This form is the answer to one of the important challenges of the land program in cities, which is fueled by the lack of land to develop and meet the new needs of the urban landscape. In such a situation, it is simply not possible to change the function and land use; Therefore, in recent decades, due to land restrictions for the development of cities and also the problems resulting from the uncontrolled and scattered growth of cities, land redevelopment as a proposed approach with an emphasis on internal development seeks to respond to the many problems of contemporary urbanism and urbanization. In the current research, while introducing the types of urban land, the special place of gray land and urban brown land was discussed from the perspective of theoretical approaches and paradigms related to them.
The purpose of this research is to investigate the potential of gray lands in urban areas and to investigate the theoretical approach related to the reuse of brown lands and gray lands. It has also investigated and analyzed its historical course in the form of sustainable urban development. The current research is descriptive-analytical in terms of applied purpose. The method of collecting information was in the form of documents and content analysis.
In the past, due to the ever-increasing expansion of cities, various topics have been stated about how cities develop, each of which has tried to provide the best for the physical development of the city: Abners Howard's Garden, Le Corbusier's shining city, Suryai Mata's linear city, industrial city Tony Garnier and others are among them. Due to the various developments in the field of land use and various views regarding how to use urban land, many theories have been proposed so far; The most important of which are the theory of the social role of land, the theory of the economic role of land, theory of natural role of land, program theory of land, modernism theory, theory of physical role of land, theory of land organization, theory of postmodernism, theory of functionalism, theory of reformism, theory of sustainable development of land use, theory of use Human, the perspective of social welfare and quality of life.
There are different views regarding the position of land in urban development, which considers the theory of access to land necessary for the development of the city and considers expansion as part of the nature of the city. In these theories, it is emphasized that cities always have a threshold in size and growth, which will stop if they reach this stage. On the contrary, some theories prescribe the compact city and consider it as one of the ways that may lead to sustainable urban development. However, there is less theorizing in these theories, which would recommend the development of the old city despite the presence of unused land and proper access to services and facilities in the existing urban contexts. This form of development will be a model of a sick city, which has lost its spatial coherence and has a porous texture and shame on its face.
The former advanced urban areas that with the passage of time and urban changes have the characteristics of abandoned, dilapidated, inactivity, and less activity. which have negative social, cultural, economic, and physical effects on the neighborhood and the city. Some of these lands may be the lands under active buildings in urban areas, which are abandoned and dilapidated in the existing state of cities. In general, before using these lands again, interventions should be made. The issue of gray lands and the reuse of these lands is considered one of the most important issues in achieving a balance between neighborhoods and urban areas. The texture of some cities includes service and commercial lands such as covered warehouses and abandoned office buildings, which in many cases have suffered a decrease in efficiency compared to their surrounding textures. The possibility of updating the texture and spontaneous change has been lost in them. The inefficiency of these uses is evident not only in physical aspects and dimensions but also in all urban areas' social, economic, functional, and identity components. The most important consequence of this is the reduction of viability and resilience of these tissues against environmental bottlenecks and frequent changes in the environment.
As a result, the stability and balance of urban areas will be lost due to the examination of urban services. The results show that currently, urban lands show the previous findings that with the passage of time and urban changes, the treatment has one of the characteristics of being abandoned and dilapidated. , which can have negative social, cultural, economic, and physical effects on the neighborhood and the city; Also, some of these lands may be lands under active construction in urban areas, which are abandoned and dilapidated in the current state of cities due to the stagnation of activities; Therefore, the issue of gray lands and the reuse of these lands is considered as one of the most important issues in achieving a balance between neighborhoods and urban areas and sustainable development. The results showed that considering the problems faced by cities in the 21st century and the issue of lack of land and the pollution of part of the urban lands, the issue of gray lands and the reuse of these lands is one of the most important issues in achieving a balance between localities. Urban areas and sustainable development are considered.