The effects of urban decisions on the pattern of city expansion (Case study: Bushehr city)
الموضوعات : Journal of Radar and Optical Remote Sensing and GIS
1 - PhD student of geography and urban planning, Islamic Azad University, Yazd, Iran
الکلمات المفتاحية: Urban decisions, horizontal urban development, Bushehr,
ملخص المقالة :
The decentralization of the population from the city centers and the suburbanization of the population, as well as the transfer of the activity centers (following the creation of transportation systems along with the existence of large and cheaper pieces of land around them) from the city centers to the outskirts are ongoing. The aim of the research was to investigate the pattern of growth and expansion of the city in the period 1363-1403. This qualitative study was conducted in Bushehr city and its suburbs. In this context, the change of urban and suburban areas in Bushehr city was studied using remote sensing techniques between 1985 and 2024. For this purpose, TM, 9, LANDSAT8 and TIRS/OLI satellite images (1985-1999) were used. Then, the slope files of urban areas for the years 1403 and 1363 were prepared using a digital tool in the ArcMap environment to be used for urban development comparisons. After determining the limits of urban growth, the type of urban development structure was determined and investigated. Based on the findings of the research, the structure of Bushehr city is multi-core and has 3 main cores: north (primary), west and east to south: 1- The expansion of Bushehr city in the northern part (primary core) is limited in terms of the density of buildings; 2- The greatest expansion has been in the eastern to southern part of the city; 3- The expansion in the western part is due to the morphological limitation of the city due to the sea.
1.Introduction
Urban expansion is one of the most significant spatial manifestations of socio-economic transformation in contemporary cities, particularly in developing and coastal regions. Decisions made by urban planners, policymakers, and governing institutions directly shape the form, direction, and sustainability of city growth. When these decisions are not aligned with environmental capacity, demographic dynamics, and spatial constraints, urban expansion often results in inefficient land use, environmental degradation, and socio-spatial inequality.
Bushehr city, located along the northern coast of the Persian Gulf, represents a unique and complex case of urban development. With a history spanning approximately 5,000 years, Bushehr has served as a strategic political, commercial, and cultural center across multiple historical periods, including the Elamite, Sassanid, and Afsharian eras. The city has historically been a pioneer in modernization processes in Iran, hosting the first stone printing press, electrical industry, ice-making facilities, and telegraph line in the region.
In recent decades, Bushehr has experienced accelerated urban growth driven by economic activities such as fishing, shipbuilding, export trade, and the establishment of critical infrastructure, including a nuclear power plant. While these developments have enhanced the city’s economic importance, they have also intensified pressure on land resources and urban governance systems. The city’s coastal location, combined with military installations, industrial zones, and natural barriers such as the sea and wetlands, has imposed significant constraints on urban expansion patterns.
This study aims to analyze the effects of urban decision-making on the spatial pattern of Bushehr’s expansion over nearly four decades (1985–2024). By employing remote sensing and spatial analysis techniques, the research seeks to identify the dominant structure of urban growth, evaluate the extent and direction of expansion, and assess the implications of horizontal sprawl for environmental sustainability and urban resilience.
- Materials and Methods
2.1 Study Area
Bushehr city is situated in southwestern Iran along the Persian Gulf coast and serves as the administrative center of Bushehr Province. The city’s historical core and surrounding neighborhoods reflect a layered urban morphology shaped by centuries of trade, governance, and cultural exchange. The dominant language spoken by residents is Persian with a Bushehri dialect, and the city has developed a strong maritime identity.
Economically, Bushehr functions as a major port city, with activities centered on fisheries, maritime transport, shipbuilding, energy production, and export-oriented industries. These functions have stimulated population growth and increased demand for housing and infrastructure. However, spatial development has been constrained by fixed physical and political barriers, including the coastline, wetlands, military zones, and the nuclear power facility, creating a highly asymmetric expansion pattern.
2.2 Research Methodology
This research adopts a qualitative–spatial analytical approach to investigate changes in the urban and suburban extent of Bushehr city over the period from 1985 to 2024. Remote sensing techniques were employed to detect, visualize, and interpret land-use changes associated with urban growth.
Satellite imagery from multiple Landsat missions—including TM, Landsat 9, Landsat 8 OLI, and TIRS/OLI—was utilized to ensure long-term temporal consistency. For each selected time period, appropriate band combinations were generated to enhance visual interpretation of built-up areas and urban boundaries. These composites enabled the identification of urban expansion fronts and changes in land cover over time.
Additionally, digital elevation and slope data were processed in the ArcMap environment to analyze the role of topography in shaping urban growth patterns. Slope maps corresponding to the years 1363 and 1402 (Iranian calendar) were prepared to compare spatial suitability for development across different periods. Following the delineation of urban growth boundaries, the structural form of urban expansion was classified and interpreted using established urban growth theories.
- Results and Discussion
3.1 Spatial Pattern of Urban Expansion
The results indicate that Bushehr’s urban expansion has predominantly taken the form of horizontal growth, characterized by outward sprawl rather than vertical densification. This expansion has occurred in multiple distinct cores, reflecting a multi-core urban structure consistent with the Ullman–Harris model of urban development.
The primary expansion core is located in the northern part of the city, which historically served as the main axis of growth. However, despite its central role, this area exhibits limitations in building density, largely due to planning constraints and infrastructural capacity. Secondary expansion cores have emerged in the western, eastern, and southern sectors of the city.
The eastern and southern directions have experienced the most substantial spatial growth, driven by relatively fewer physical constraints and greater availability of developable land. In contrast, expansion in the western sector has been significantly restricted by the presence of the Persian Gulf, resulting in morphological limitations and fragmented development patterns.
Comparative analysis of urban land area between 1985 and 2024 reveals a marked increase in both urban and suburban land coverage. This growth, however, has been largely uncoordinated, reflecting reactive rather than strategic urban decision-making. The spatial dispersion of development has increased infrastructure costs, reduced land-use efficiency, and intensified environmental pressures on sensitive coastal and wetland ecosystems.
- Conclusion
The findings of this study demonstrate that the horizontal expansion of Bushehr city is the outcome of intertwined demographic pressures, economic drivers, geopolitical constraints, and planning decisions. While urban growth has contributed to economic development and regional prominence, the prevailing pattern of low-density horizontal sprawl has generated significant environmental, social, and administrative challenges.
From an environmental perspective, unplanned outward expansion has encroached upon coastal lands, wetlands, and agricultural areas, increasing vulnerability to erosion, flooding, and ecological degradation. Socially, dispersed development has fragmented the urban fabric, weakened social cohesion, and exacerbated inequalities in access to services, infrastructure, and public spaces. Economically, the inefficiencies of horizontal growth have placed considerable strain on municipal resources, increasing the cost of service provision and infrastructure maintenance.
The city’s future development is further constrained by immovable barriers, including military installations, the nuclear power plant, and natural features such as the sea and swampy lands. These limitations underscore the unsustainability of continued reliance on horizontal expansion as the dominant growth strategy.
To address these challenges, a fundamental shift in urban planning policy is required. Emphasis should be placed on compact urban development, revitalization of the urban core, mixed land-use planning, and vertical densification. Integrating environmental sensitivity, spatial justice, and infrastructure efficiency into decision-making processes is essential for enhancing Bushehr’s long-term resilience and livability.
In summary, Bushehr exhibits a multi-core urban structure with three principal expansion zones: a primary northern core and secondary western and eastern–southern cores. The northern core faces density limitations, the eastern and southern areas have absorbed the majority of growth, and western expansion remains constrained by coastal morphology. The experience of Bushehr provides valuable lessons for other coastal and developing cities confronting similar growth pressures. Adopting data-driven, sustainable, and inclusive urban planning strategies can enable cities to balance economic development with environmental protection and social well-being.
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