Abstract
This chapter applies a design-based approach to integrate the innovative greenery measures in a high-density unplanned area of Imbaba to mitigate the urban heat island (UHI) effect and provide high quality open spaces by creating a chain of cooling public spaces called “Takeeba.” The literature review was applied to propagate the formulation of the research problems and identify the boundaries of knowledge. Land surface temperature (LST), the normalized difference vegetation index (NDVI), and the normalized difference built-up index (NDBI) were mapped using remote sensing to identify the hotspots and the existence of greenery and vacant lands for intervention. Prioritizing the hotspots shows vacant land and parking lots are the hottest spots due to direct exposure to solar radiation and heavily compacted areas in the centre of Imbaba. To tackle UHI in the whole Greater Cairo, the replicability of the idea was considered in a follow-up project.
TopIntroduction
Rapid urban growth increases concern for the future of cities and the health of inhabitants. It causes the natural environment to be replaced with built-up areas to accommodate overpopulation, quick construction without considering the local climatic conditions, the expansion of city size, high traffic congestion, production of anthropogenic heat, and many others emerged urban microclimate change called urban heat island (UHI). This phenomenon occurs, in fact, by absorbing solar radiation through urban surfaces and storing it during the day; and re-emitting it to the environment at night-time. This creates higher temperature differences between urban and rural areas and leads to several negative impacts on various aspects of life, including increased morbidity and mortality risks, low air quality, and reduction of natural resources. However, health risks are more severe than the other potential threats.
Therefore, the paper focuses on integrating greenery into a compact, unplanned area in Greater Cairo called Imbaba by designing a chain of cooling public spaces in different scales to provide urban thermal comfort for the inhabitants, especially who are more vulnerable to climate change and have less access to essential services and infrastructure as well as to increase their health condition, last but not least, to boost rehabilitation along the Nile and re-establish high quality urban life. It has been proven that greenery is able to decrease the health effects of the UHI by removing pollutants from the air (Solecki et al., 2005) and blocking solar radiation by providing shadow.
Through a mapping exercise of one of the most vulnerable typologies of Greater Cairo, the paper identifies possible assets and challenges in terms of available land/surfaces, water/reused wastewater, and the acceptability of interventions. Then, it suggests a matrix of possible innovative greenery interventions responsive to these different urban structure typologies.
The preliminary analysis done by mapping LST, NDVI and NDBI ascertain that the extent and severity of UHI depend on the sorts of land uses located in the city. Prioritizing the hotspots (high surface temperature) shows that vacant lands and parking lots are the hottest and greeneries are the most incredible spots. It is undeniable that greenery plays a crucial role in regulating surface temperatures. The heavily compact built-up areas are the second hotspots due to the lack of vegetation and using low albedo materials.
The paper proposes designing several interconnected cooling public spaces called “Takeeba” for the identified hottest spots in Imbaba, starting from a vacant land along the Nile, followed by further interventions into the target area and extended into alternative vacant lands near Imbaba park.
The overall goal of the paper is a collaborative contribution to Greater Cairo towards becoming a sustainable city as defined in the New Urban Agenda (NUA) and the United Nations Sustainable Development Goals (SDG) – especially concerning three goals:
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SDG 3: ‘good health and well-being.’
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SDG 11: ‘sustainable cities and communities
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SDG 13: ‘climate action.’
To achieve the goal, the paper addresses the UHI phenomenon to adapt to urban climate change, reduce carbon emission, increase thermal comfort and health of inhabitants, and re-establishing high-quality urban life.
Key Terms in this Chapter
Greenery Measure: A measure that integrates greenery into an urban area to interrupt microclimate changes in the urban canyon, decrease the anthropogenic heat and the energy consumption in the surrounding buildings as well as increase evapotranspiration and contribute to creating lower temperature spaces.
Cooling Public Space: A public space that provides breathing points for an urban area as well as thermal comfort for citizens.
Urban Acupuncture: An architectural design practice of urban regeneration with the goal of having a transformative and revitalizing impact on that area and its surroundings.
Urban Heat Island: An urban area that absorbs and retains significant solar radiation than rural areas.
Unplanned Area: An area where either houses have been constructed on land that the occupants have no legal claim to or occupy illegally, or own the land but have no permit to build. The area is determined according to the strategic urban plan for each settlement according to the Egyptian Unified Building Law.
Urban Health: The well-being and health of people who live in the cities.
Takeeba: A wooden light structure covered with plants to provide shade and breeze for cooling down and relaxing in hot days of summer.