Noha E. Abdelwarth*
Assistant Researcher at Agricultural Engineering Research Institute (AEnRI),
Agricultural Research center (ARC), Egypt.
Urban sprawl is considered as a danger that grows to the point of disaster, especially when it comes to unjust encroachment on agricultural lands, which is a crime against peoples and their food security. In recent decades, urban growth has not been adopted with the needs of the population and as a result of this process; many farmland has been used for construction.
It is a great loss that appeared recently with the global Coronavirus (COVID-19) pandemic, the closure of borders and the need for countries to be self-reliant. After studying the role of GIS in monitoring reality during 30 years and predicting the sprawl in the next years, the most important results showed that this technique is an effective tool that must be recommended to be adopted to confront random urban sprawl to stop disasters arising from this event.
Key words: urban sprawl; Geographic information systems; Disaster risk.
Urban sprawl can be considered a silent cancer that grows through the ages and is against the law. The randomness of the continuous construction throughout the ages makes the building lack of safety and construction factors. The slum area lacks of planning to provide with the necessary facilities and urgent relief services in case of danger. Cancerous urban sprawl also leads to a demographic problem that is the focus of other social disasters as a result of poor planning to create a random population society that is lack of all the features of health, morals and education.
Therefore, the necessity now appears in front of governments after the aggravation of the disaster in the impossibility of an ideal re-planning of all cases on the ground which resulted by a long period of randomized urban sprawl. Therefore, it is the important to resorting to geographic information systems (GIS) to play an effective role in trying to stop the cancerous expansion of highly urbanization, taking advantage of the difficulty of spatial control in the distant ends of the Earth.
The 2009 Global Assessment Report on Disaster Risk Reduction (GAR) discusses in detail the process of urban sprawl and increased risk of disasters. (UNFPA, UNISDR 2012) These negative impacts can be summarized as:
1. Flood and flash flood disasters risk: Unplanned urban area is suffered from lack of required infrastructure and services like potable water supply, electricity, gas, drainage systems and many other services. Lake of drainage systems exposes these areas to hazards.
2. Climate change disaster risk: Urbanization resulted in near-surface temperature increases of more than 1ͦK over the urban sites during both winter and summer. (Lamptey, Barron, and Pollard 2005)
3. Pollution disaster risk: urban sprawl has many negative consequences for residents and the environment, such as higher water and air pollution. Environmental degradation in rapidly urbanizing regions has negative impact on human and ecosystem health. (Duh et al. 2008) 4. Loss of farmland that secures food requirements: that loss appeared recently with the global Coronavirus (COVID-19) pandemic, the closure of borders and the need for countries to become self-reliant.
Fig (1): impact of flash flood in unplanned urban area in Egypt at Nov. 2020
The study aims study the role of GIS as a management tool to stop the epicenter of the urban sprawl disaster
1. Detecting the urban sprawl over 30 years.
2. Predicting future urban sprawl.
3. Proposing Policies and method for controlling urban sprawl.
Sherbin district is selected as representative of the Nile delta. The district suffered from unplanned urban sprawl as all Nile delta lands. Sherbin district is located in Dakahlia governorate on the northern of Nile delta, Egypt (31.21° - 31.08° N, 31.26° - 31.40° E). Population is estimated 438,102 (2019) and the area of the district is 1,602,900 ha. Agricultural lands represented most of the area which is estimated 25,913 ha. The district covered a large portion of food production. (Egypt: Administrative Division - City Population n.d.)
Causes of urban sprawl in Sherbin district:
1. Rapid population growth.
2. The absence of a desert expansion land.
3. The low price of agricultural land compared to the urban area.
4. Low income of the population.
5. Smallness of agricultural land ownerships.
6. Lack of planning that does not adequate to realistic requirements.
All the following steps were accomplished using ArcGIS Pro 2.6.
1. The Urban sprawl detection over 30 years:
Detecting land use/cover change (LULC) provides a proper background for environmental, planning, and urban management analysis. However, detecting land use/cover is not easy due to various factors. (Dadras et al. 2014)
To detect land use/cover change (LULC) over 30 years, 20 Landsat 5 and 8 images are collected from 1990 to 2020 for each year. The roads were masked form the images then images were classified using maximum likelihood supervised classification tool to agricultural lands, urban, and water. Then the urban sprawl was estimated.
2. Predicting future urban sprawl:
Future urban sprawl was predicted for year 2030 by the following steps:
8 LULC raster datasets for years 2013 to 2020 that extracted by Landsat 8 imageries were combined together in a multidimensional mosaic dataset. Trend raster dataset is generated for the mosaic dataset by generate trend raster tool. Predicted raster datasets for urban area were created by predict using trend raster tool.
1. The Urban sprawl detection over 30 years
Fig (2) shows the urban area that extracted from Landsat imageries at 1990, 2002 and 2010. The new urban area built up on agriculture lands by 2002 and 2010 were 152 ha and 110 ha respectively.
Fig (2): Urban area that built up by 1990, 2002, and 2010
On the other hand, Fig (3) shows that 1045 ha of fertile agricultural lands were lost by urban sprawl during the period of 2010 to 2020. According to Fig (3), it is noticed that the urban sprawl was rapid in period between 2010 and 2020. The urban area increased from 1815.84 ha at 2010 to 2860.56 ha at 2020. Also it is very random and far from the old urban area. Fig (4) illustrates the growing of urban area during 1990 to 2020 which obtained from the LULC. It shows that in 2011 a significant and dramatic increase in urban sprawl occurred, which can be explained as a result of the political situation.
Fig (3): Urban area that built up by 2010, 2013, 2016 and 2020
Fig (4): Urban area during 1990 to 2020
2. Predicting future urban sprawl
Fig (5) illustrates new predicted urban area by 2023. According to the analysis, the new predicted urban area estimated 370 ha. Also, it is noticed that randomization of urban sprawl occupation will be continued in the agricultural lands.
Fig (5): predicted urban area by 2023
3. Policies and method for controlling urban sprawl
The results show that the urban sprawl at the next year will continue to be excessive, rapid and random in agricultural fields. If we deal with the sprawl on agricultural land, then we must stop and sound an alarm to confront the disaster that has been achieved in the simplest description, as the risk doubles in the form of crimes against the food security of peoples. But if we look at the multiplicity of risks due to the unfair and unjust urban sprawl, we have to pay attention to the need for permanent planning, and urban expansion with stability and rapid population growth. (Habibi, S, and Asadi 2011) proposed some policies to control urban sprawl and to decrease its negative effects. There are many policies that each one concentrates on a different aspect of this issue.
• Create urban boundaries: Urban boundaries in edges of cities will control urban sprawl. In this regard, only constructing in inner districts will be allowed and urban size will not be extended. • Participate in providing infrastructure costs: Surveys show that urban sprawl has got costs 20 times more than the normal growth because of needs to news ways, schools, housing and public services. So, increasing resident’s share of costs plays an important role in controlling sprawl.
• Betterment of low-income household’s living conditions: One important part of residents in suburb is people who migrate for improvement of their family life. Paying financial credits, preparation of Affordable housing and regional subsidies are some solutions for improving their living condition.
• Redevelopment of inner-core regions: This action causes an increase in urban land price. Usage of lands and enterprising in industrial abandoned lands, blank commercial plots and metro stations spaces, Rehabilitation of abandoned properties and historic buildings are some examples of this policy.
• Control growth and protection of lands: Open spaces have high value tax determination for changing Land uses causes a decrease in the rate of land changes.
• Urban consolidation: Urban consolidation has been introduced as a solution for more appropriate utilization of lands and infrastructures in the built up area of a city. It pursuits restriction of using urban Lands, reduction of infrastructure costs, and using of more public transportation.
• Support smart growth strategies: Smart growth concentrate on compact development and redevelopment built up area in a city. Creative and efficient management: presenting creative urban policies will cause an appropriate growth. So, planners should be able to determine value and direction of development and its costs.
In this study, Geographic Information Systems (GIS) was used to detect the urban sprawl on agricultural lands, to study whether it could play an effective role in addressing the focus of the disaster represented by the random spread of cancerous urbanization, and its consequences. The observation images over 30 years have shown that the disaster severity curve is reached in creep over lost farmland areas from year to year. 1045 ha of fertile agricultural lands were lost by urban sprawl during the period of 2010 to 2020, and the prediction analysis found that the continuous cancer of urban sprawl will occupy 370 ha by 2023.
The results confirm the urgent need for governments to GIS to develop policies for implementing appropriate solutions to control urban sprawl according to the characteristics of regions and cities. In conclusion, the study ends with a recommendation for further research into all aspects of the disaster arising from the spread of urban sprawl cancer that was not covered by this study, with a focus on adopting geographic information systems technology in this regard.
Dadras, Mohsen et al. 2014. “Land Use / Cover Change Detection and Urban Sprawl Analysis in Bandar Abbas City , Iran.” The Scientific World Journal 2014: 12.
Duh, Jiunn-der, Vivek Shandas, Heejun Chang, and Linda A George. 2008. “Rates of Urbanisation and the Resiliency of Air and Water Quality.” Science of the Total Environment, The 400(1– 3): 238–56. http://dx.doi.org/10.1016/j.scitotenv.2008.05.002.
“Egypt: Administrative Division - City Population.”
https://www.citypopulation.de/en/egypt/admin/ (November 28, 2020).
Habibi, S, and N Asadi. 2011. “Causes, Results and Methods of Controlling Urban Sprawl.” 21: 133–41. http://dx.doi.org/10.1016/j.proeng.2011.11.1996.
Lamptey, B L, E J Barron, and D Pollard. 2005. “Impacts of Agriculture and Urbanization on the Climate of the Northeastern United States.” Global and Planetary Change 49: 203–21.
UNFPA, UNISDR, UN-HABITAT. 2012. LINKAGES BETWEEN POPULATION DYNAMICS , URBANIZATION PROCESSES AND DISASTER RISKS :
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