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‘ Human factors ’, not just the climate crisis , aggravated KZN floods - top hydrology researcher
Professor Emeritus of Hydrology at the University of KwaZulu-Natal ’ s Centre for Water Resources Research argues that not just heavy rain and climate change were responsible for the devastation in Durban and other provincial areas .
Tony Carnie
Current Address : Daily Maverick Reprinted from : https :// bit . ly / 3cDgsoL
Given the devastating impact of the “ rainbombs ” that struck Durban and other parts of the KwaZulu-Natal coast in April and May , it ’ s no surprise that several commentators have described the recent floods as the worst in living memory — and also linked them to the global climate crisis .
Yet , contrary to popular perception , detailed historical analysis suggests that the KZN coastline has experienced many similar events over the past 170 years — some of them significantly worse in terms of the volume or intensity of rainfall ( see historical details further below ).
While the jury is still out on the extent to which the April / May 2022 weather events were driven by human-induced climate change , one of South Africa ’ s most senior hydrology researchers suggests that it is equally important to interrogate and address the wide variety of “ human factors ” that aggravated the severity and human death toll of the most recent floods .
Roland Schulze , Professor Emeritus of Hydrology at the University of KwaZulu- Natal ’ s Centre for Water Resources Research , says the rapid and widespread expansion of human settlement and industrial development around Durban has created vast new areas of hard , impervious surfaces which exacerbate the erosive power of floodwaters .
Figure 1 . Cars are seen semi-submerged on the road during severe floods on 10 October 2017 in Durban , South Africa . ( Photo : Gallo Images / The Times / Thuli Dlamini )
Whereas larger areas of grasslands , gardens and undisturbed natural vegetation once helped to absorb or disperse floodwaters , the almost wall-to-wall covering of concrete , brick paving or tarred roads in some parts of the city has promoted faster and more intense water channelling and scouring .
Due to the lack of strict planning controls on where to build or how to build , several informal homes had been built in vulnerable floodplains . In other places , homes were built on steep slopes ( often with unstable soils ) or without adequate foundations .
Schulze also suggests that the proliferation of shallow-rooted alien plants along river courses was a further contributing factor . Quoting research by eThekwini
35 Grassroots Vol 22 No 2 July 2022