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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge


Yair Perry

The Value of Blue and Green Infrastructure for the Growing Cities of the Global South

Blue Green Infrastructure (BGI) is at the heart of Water Sensitive Cities (WSC), a new paradigm of urban development for improving the resilience of cities to the stresses of population growth and the consequences of climate change, such as the increasing frequency of droughts and intense rainstorms. BGI promotes the use of nature-based solutions to mitigate flood risks, enhance local ecosystems and improve fresh water sources through limiting runoff and enhancing groundwater infiltration. Previous studies have predominantly focused on BGI adoption in Europe, North America and Australia. This dissertation examines case studies of BGI use in cities of the global south to determine the additional benefits achievable by its installation alongside traditional infrastructure. As the urban growth rate is exceeding planning in many developing countries, marginalized populations are left underserved by basic services such as sanitation and piped water, and they are more vulnerable to natural hazards. Kisumu, the third largest city in Kenya, is used as a case study to show how the findings can be implemented. The city is experiencing floods on a yearly basis while facing a large infrastructure gap constraining the provision of sanitation and water services to almost half of its 500,000 residents living in informal settlements. Using Geographic Information System (GIS) spatial data, the current state, and historical records of flood impact on the city, possible BGI interventions are assessed. The multiple benefits of BGI are shown to be invaluable to the sustainable growth of cities like Kisumu facing ongoing population growth and the uncertainty of climate change.