Population growth and economic upswings are the usual drivers of urban sprawl. People moving out of the city center, expanding the suburbs, and driving the need for supporting businesses can have several negative effects on the area, from increased water consumption and changes in air quality to loss of agricultural land and increased traffic and traffic fatalities. In developing countries, uncontrolled growth can be exacerbated, leading to scattered settlements with little to no infrastructure support.
In a study in the Journal of Urban Planning and Development, researcher Ibrahim M. Badwi used Egypt’s greater Cairo region as a case study. Performing a literature review, Badwi identified four variables affecting urban growth: topography, building code and tax issues, vegetation, and population. In Cairo, the author discovered that vacant lots were developed unexpectedly, creating pop-up settlements. Farmers were dividing their land into smaller lots. Both use cases put stress on user services funded by taxes. Using spatiotemporal data, Badwi’s paper, “Integrated Multicriteria Approach for Assessing Land Suitability and Predicting Informal Growth: The Case of the Greater Cairo Region, Egypt,” weighed the various growth factors to develop a historical probability map. Then, the author applied several processes to analyze the neighborhoods around Cairo and identify the most sensitive areas. Not surprisingly, growth along transportation routes and existing development was identified, but so was growth into areas that could threaten food production and security. Learn more about this study and get insight on how to control unplanned urban sprawl at https://doi.org/10.1061/JUPDDM.UPENG-4502. The abstract is below.
Abstract
Prediction and monitoring of urban sprawl is a significant urban issue for planners, decision makers, and local authorities in terms of spatial data, strategies, and prediction models. Egyptian cities have expanded rapidly in the last 40 years. This uncontrolled urban growth requires a review of Egyptian urban policies and regulations. The Greater Cairo Region (GCR) is Egypt’s economic capital and a significant industrial and commercial city. This study uses spatio-temporal data to suggest an approach based on integrating cellular automata (CA) and multicriteria evaluation (MCE) like analytical hierarchy process (AHP) and running it within the geographical information system (GIS) for monitoring, analyzing, and allocating informal growth in the context of unplanned regions like the GCR. At first, the weights of influencing growth factors were determined and calculated using AHP. Next, the probability map was created according to AHP weights. The historical probability map was then generated based on the historical development. Then a standalone CA macro was developed based on AHP weights to calculate the proximity index for existing urban and transportation features using Moore’s extended neighborhood matrix. Finally, the general suitability map was created to identify the most sensitive areas for growth over the next two decades. The prediction process was performed based on the 2012 urban boundary. Then, the prediction accuracy was verified using the Kappa coefficient based on actual urban extents in 2017. The results showed that 676 km2 (35%) of the study area was not sensitive, 386.5 km2 (20%) was slightly sensitive, 522 km2 (27%) was almost sensitive, and 348 km2 (18%) was extremely sensitive to urban sprawl. Finally, we predicted the urban growth for the period from 2022 to 2052 for every 5 years. The outcomes showed a linear scattered sprawl pattern along transportation features and an annular pattern around existing urban spaces. Therefore, fertile farming land and natural resources in the GCR are set to become almost extinct over the next two decades, threatening food production and security. These results indicate the necessity to modify the region’s urban policies to protect the agricultural areas and control the unplanned urban sprawl.
Read more about the suburban Cairo experience, consider how your urban area relates and what may need to happen in the ASCE Library: https://doi.org/10.1061/JUPDDM.UPENG-4502.
