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Roy, Shilpi; Sowgat, Tanjil; Islam, S. M. Tafsirul; Anjum, Nafisa
2021 Environment and Urbanization Asia
Dhaka’s sprawled area is likely to supersede the total land area of the Dhaka city in the near future. This article combines quantitative and qualitative methods to investigate sustainability concerns that have arisen because of irregular and rapid sprawling in Dhaka. Land cover change detection reveals that since 1991, the city outskirts have seen an addition of 234 square kilometres of built-up area. Spatial metrics show the dynamic process of infill and the fragmented transformation of land covers in Dhaka, which have led to low-density, leapfrog and ribbon sprawling. The city outskirts, especially the economically advantaged regions, have been observing rapid urban densification of neighbourhoods. Field observation and interviews in 19 sprawled areas confirm that the change has been influenced by industrialization, increasing demand for housing, high cost of living in Dhaka city, growing population and lack of development control regulations. The advantage of the sprawling process is that it offers economic opportunities, contributing to poverty reduction and national economic growth. However, the abrupt and sporadic nature of this transformation puts the long term economic and environmental viability of new business activities and habitation into question. Congested housing, poor accessibility, inadequate drainage system and sanitation facilities in sprawled areas have resulted in poor liveability and created social inequality, thus impeding the way for a sustainable urban transformation of peri-urban Dhaka. This article calls for a greater acknowledgement of sustainability concerns in development control regulations and a more inclusive form of governance to deal with existing sustainability challenges for Dhaka city and its rapidly transforming peripheral region.
Daguio, Keith Gerard L.; Rivera, Ryan Randle B.; Reyes, Mario R. Delos; Santiago, Joy T.; Mendoza, Jerico E.
2021 Environment and Urbanization Asia
This article, using a combination of quantitative and qualitative approaches, illustrates that Batangas City for the period 1990–2015 was leaning towards a sprawling development. Areas where considerable sprawling has occurred were further investigated in relation to land value. The study also revealed that there is a moderate positive relationship between sprawl and land values in the city, which meant that land values have increased in areas where considerable sprawling has occurred.
Scheba, Andreas; Turok, Ivan; Visagie, Justin
2021 Environment and Urbanization Asia
Global policies promote urban compaction to achieve sustainable development. This article highlights the limits of analysing densification at the city scale and advocates for a more granular approach. The case study of Cape Town shows how overall consolidation has been mainly driven by poor households crowding into already dense neighbourhoods on the urban periphery. This has aggravated historic segregation and intensified urban management challenges. Meanwhile, formal private sector driven densification strengthens the social and economic vibrancy of affluent neighbourhoods. This article argues that uneven residential patterns reflect deep-seated social inequalities that are amplified through labour and property markets. Satellite data also illustrates how Cape Town’s built-up area has changed between 1998 and 2019. Based on geo-spatial analyses, the article suggests that taking these drivers seriously is crucial to promoting a denser and more equitable urban form. Aligning housing policies with spatial transformation and economic development objectives offer possibilities for change.
Nduwayezu, Gilbert; Manirakiza, Vincent; Mugabe, Leon; Malonza, Josephine Mwongeli
2021 Environment and Urbanization Asia
Kigali is a rapidly growing city, as exemplified by the phenomenal increase of its inhabitants from 358,200 in 1996 to 1,630,657 in 2017. Nevertheless, there is a paucity of detailed analytical information about the processes and factors driving unprecedented urban growth in the period following the genocide perpetrated against the Tutsi (1994) and its impact on the natural environment. This article, therefore, analyses the growth of the city of Kigali with respect to its post-genocide spatial and demographic dimensions. The methodology involves a quantification of urban growth over the period of the last 30 years using remote-sensing imagery coupled with demographic data drawn from different sources. The analysis of land cover trends shows how significant the pressure of urban expansion has been on the natural environment, with a 14 per cent decrease in open land between 1999 and 2018. Spatially, the average annual growth rate was almost 10.24 per cent during the same period. This growth is associated with the building of a large number of institutions, schools and industries. Moreover, the increase in low-income residents led to the construction of bungalows expanding on large suburbs and the development of new sub-centres in the periphery instead of high-rise apartments.
2021 Environment and Urbanization Asia
Johannesburg and the broader Gauteng City-Region in which it is located are considered to be the economic powerhouse of South Africa. This has led to massive population growth in the region, as well as severe inequality. Given South Africa’s history of racially excluding black South Africans from urban areas, ongoing research in this area has to analyse land cover and define ‘sprawl’ in a context where the technical language has politically loaded overtones. This article tries to understand the scale of informality within a broader examination of urbanization and sprawl. It concludes that in the absence of a formally adopted urban edge and under massive pressure from population growth (natural and via migration), formal dwellings (residential and economic) have grown unchecked, and informality is now growing at high speed and also largely without regulation or control. With no apparent political will to stop urban sprawl, both informal and formal covers are steadily pushing towards provincial borders, while densifying in Johannesburg in particular.
Sun, Xuan; Liu, Yunxia; Sun, Tao; Yu, Sihang; Li, Chenguang; Zhai, Lie
2021 Environment and Urbanization Asia
China has experienced an unprecedented rate of urbanization in recent decades. As a city with strong political and economic influences in the southwest of China, Chongqing is a typical example of rapidurban development in this period of time. To study the land cover changes and urban expansion of Chongqing, Landsat images from 1999 to 2018 were selected, processed, and quantitatively analysed The results showed that the built-up area of the city had increased tremendously during these years, yet vegetation still accounted for the vast majority of the city’s land area. Restricted by the local topography including mountains and hills and infrastructure constructions, the urbanization process that occurred in central Chongqing actually showed a dominant expansion direction, an obvious spatial clustering tendency, and significant spatio-temporal differences among various regions.
Mondal, Biswajit; Sharma, Pragya; Kundu, Debolina; Bansal, Sarita
2021 Environment and Urbanization Asia
doi: 10.1177/09754253211007830
Urbanization is considered as the key driver for land use and land cover (LULC) changes across the globe and Delhi is no exception to this phenomenon. The population of Delhi has almost doubled from 8.4 million in 1991 to 16.3 million in 2011. Correspondingly, the built-up area has also increased from 336.82 to 598.22 km2 during 1999–2018. This urban expansion has led to emergence of serious ecological risk and fragmentation of the landscape. In this context, it is imperative to analyse the level of risks induced by such urban expansion and its underlying associations with other factors. This article quantifies the LULC changes in Delhi during 1999–2018 using Landsat 5 (TM) and Landsat 8 (OLI) data. A spatio-temporal sprawl induced risk assessment index has been developed by combining landscape fragmentation score and land use land cover vulnerability score. The landscape fragmentation score was based on four landscape metrics, whereas the vulnerability score was computed from LULC data. The article also assesses the association between risk areas and economic activities, environmental and infrastructural amenities that are considered key drivers of urban expansion in Delhi. To estimate spatio-temporal variability between risk areas and key drivers, ordinary least square regression and geographical weighted regression (GWR) were used. The GWR results reveal that sprawl-induced ecological risk in Delhi is strongly associated with economic activity, infrastructural accessibility and environmental amenities. This spatial empirical assessment also shows that urban growth incentives or services such as roads, metro rail, schools and hospitals can also create pressure on the landscape if local authorities arbitrarily provide these services across space without considering the associated risks.
Msuya, Ibrahim; Moshi, Irene; Levira, Francis
2021 Environment and Urbanization Asia
Dar es Salaam is one of the most diverse cities in Tanzania in terms of its physical, social, economic, environmental and spatial features. This diversity has contributed to differences in built-up area, population density, as well as the pace of spatial development across different parts of the city. This study aims to examine the relationship between physical built-up area changes in Dar es Salaam, population density change and spatial development using remote sensing images and census data. The study finds that the city population has grown tremendously, with peri-urban wards in particular having experienced positive growth. Dar es Salam’s built-up area change and urban sprawl emerging at the city’s edges distinctly follows the pattern of demographic change. This is accompanied by substantial compact growth in the inner parts of the city. A number of factors such as transport, residential development, migration, high natural growth rates, public policies and land speculation are found to have contributed to these changes. Overall, the study aims to aid planning authorities in effectively responding to the rapid spatial development taking place in the city, for which a holistic approach that combines an understanding of physical and demographic changes is needed. By investigating the changing patterns in land use within this highly urbanizing city, it aims to generate insights into urban development control machineries and identify their underlying dynamics.