Concrete Expansion: Urban Growth Estimation Through Geo informatics, A Case Study of Karachi

Abstract

Karachi, once the capital of Pakistan and now it is the capital city of Sindh province, stands as the country’s largest city and the 12th most populous city globally. It plays an important role in the country’s economy by contributing 60-70% of its total revenue. However, the city struggles with the challenges of rapid urban sprawl, a preventable trend, particularly in developing countries. The uncontrolled expansion of Karachi’s urban landscape, often referred to as the “concrete jungle” poses significant risks due to inadequate management and a lack of long-term planning. It is a great risk to manage the urbanization of this city of light because of mismanagement and development without long-term planning. The expansion of the urban population has brought several issues such as increased population density, resource deficit, management challenges ecological pressure, etc. The expansion of the city is the uncontrolled spreading of urban growth. Remote sensing and GIS are now being used for change detection and applications. Urban expansion is one of them, which can be analyzed efficiently by using satellite data available online in the form of present as well as historical images in different spatial resolutions. In this study, change detection techniques have been used to assess urban growth through the historical maps with Landsat 7 ETM+ sensor of 2002 and Landsat 8 OLI images of 2022. Utilizing the satellite images, conducted measurements and analysis to assess the urban growth of Karachi. Although the many unstable conditions in this city, its population growth is tremendous i.e. approximately 4% per year. This growth is due to high natural increase as well as substantial migration from other parts of the country. It is measured that the living population in 1998 was 9.34 million and in the census 2017 that population became 15 million, which was far greater than in 1998. Over the past two to two-and-a-half decades, Karachi has expanded at a rate of approximately 15 percent annually, incorporating an additional 2 sq. km/year to accommodate its growing population, resulting in a significantly high population density.