The Anthropogenic Roots of Increased Flooding in Kano, Nigeria

by Dan McCabe

Intelligent planning for urban development requires an understanding of how different development paths can impact sustainability. In order to better understand what aspects of cities impact sustainability, Barau et al. (2015) investigated historical trends in the environmental resilience of Kano, Nigeria. Kano, northern Nigeria’s largest city with a population of over 2 million, has been a commercial center since the 10th century and has experienced extreme morphological changes in the centuries since then. Recently, the city has been subject to an increasing number of catastrophic flooding events that have caused deaths, exacerbated the spread of infectious diseases, and forced the relocation of hundreds of thousands of residents. As the frequency of extreme weather threatens to increase due to global climate change, Kano’s ability to respond to flooding is of great concern. Barau et al. therefore sought to determine how the city’s evolution has made it especially prone to severe floods.

In order to determine the relationship between Kano’s development and environmental problems, the authors examined an assortment of historical images and texts to gain understanding about the city’s structure. Their research was guided by the coupled human and natural systems (CHANS) framework, which is centered on the idea that anthropogenic and environmental variables combine to influence urban sustainability in a nonlinear way. From their analysis of both modern and historical sources, the researchers found that Kano has undergone extremely rapid spatial change between 1826, the date of the earliest informal map of the city available, and the present day. Specifically, natural building and roofing materials (primarily mud and clay) gave way to structures of impervious cement and metal. At the same time, streets came to take over more of the city area and became paved, ponds in the city decreased in number and size, and once-abundant green space was almost entirely eliminated. Overall, it was obvious that there was a drastic decrease in the prevalence of structural and ecological features that previously helped the city tolerate flood conditions. Western colonization originally brought along technology that altered the development of Kano’s highly natural landscape, and eventually the relatively natural state of the city gave way to urban planning and engineering methods that removed most of Kano’s open space and water. This transformation led to decreased rainfall absorption and greater runoff, turning rain events that once were manageable into more severe floods.

In addition to presenting insight into the forces that have caused environmental problems in Kano, the research demonstrates the importance of interdisciplinary approaches to assessing the environmental repercussions of urban development. Land use in cities is driven by policy, technology, history, culture, and more, all of which interact with one another nonlinearly, so it is necessary to holistically assess human impacts on the natural environment. In the Global South in particular, where cities’ ancient structures impact their modern-day layouts, a thorough consideration of what shapes development is crucial. Understanding this relationship will be vital to global sustainability as the populations of cities across the planet continue to grow.

Baron, A.S., Maconachie, R., Ludin, A., Abdulhamid, A. (2015). Urban morphology dynamics and environmental change in Kano, Nigeria. Land Use Policy 42, 307-317.

http://www.sciencedirect.com/science/article/pii/S0264837714001835

 

TAGS: Climate change, natural disasters, flooding, Global South, urban development, Kano, Nigeria, urban planning, Aliyu Salisu Barau, Roy Maconachie, A.N.M Ludin, Adnan Abdulhamid

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