New research suggests flooding events in KwaZulu-Natal have doubled over the last century or more
A disastrous flood hit Durban, South Africa in 2022. A new study has confirmed it was the most catastrophic natural disaster yet recorded in KwaZulu-Natal (KZN) in terms of lives lost, homes and infrastructure damaged or destroyed and economic impact.
The research was conducted by the University of the Witwatersrand in Johannesburg, South Africa and the University of Brighton, the United Kingdom and published in the South African Geographical Journal April 11, 2023.
Parts of KZN coastal zone, including the greater Durban area and South Coast, received more than 300 millimetres of rain in 24 hours from the slow-moving storm Issa on April 11-12, 2022.
Flooding and landslides claimed the lives of 459 people. More than 4,000 homes were destroyed and over 40,000 people became homeless. Infrastructure and business losses went up to an estimated $2 billion.
The floods brought the provincial economic hub of Durban to a near standstill, causing more damage than what the city and provincial authorities had the capacity and resources to deal with. President Cyril Ramaphosa declared a national state of disaster due to the severity of the situation.
National and international media reports called the heavy rain and flooding and mass movement events as “smashing weather records”. However, no systematic and up-to-date flood record exists for KZN to allow the April 2022 floods to be viewed within their full historical context.
The study presented a historical geographic account of flooding in the province, focusing on the greater Durban region.
The researchers constructed a geographical history of flooding disasters in KZN by sifting through thousands of archived articles held in old newspapers, colonial and government records, early missionary records, and meteorological records, which became available from the 1850s.
The researchers defined extreme flooding events, where major rivers were overflowing their banks, together with one or more significant consequences, such as the loss of human life, livestock, agricultural fields and crops and infrastructure such as buildings, roads and bridges.
The first documented significant flood event to affect Durban was in April 1848, when the Ungeni river overflowed its banks.
Three days of heavy continuous rains over the Durban-Pietermaritzburg region in March 1849 resulted in loss of human life, rivers flooding roads and damage to infrastructure.
In this study, the researchers documented 53 significant flood events from 1850-1899 and a total of 210 significant flood events over KZN from 1900–2022.
A catastrophic flooding event in Durban, 1856, also in April — produced a greater quantity of rainfall over a three-day period.
In April 1856 303 mm of rain fell in Durban over 24 hours and a record of 691 mm over three days from April 14 to April 16. During these historic floods, an unknown number of people drowned, the entire central area of Durban was flooded, bridges were destroyed and roads were closed for several days.
Durban was only a town with a much smaller population and economic infrastructure back then. Thus, the percentage of individuals impacted or economic loss may have been greater in 1856.
The study confirmed that the April 2022 floods were likely the most catastrophic natural disaster yet recorded in KZN in collective terms of lives lost and overall economic impact.
Stefan Grab, the lead author of the study, said:
“Within the limits of our data, we suggest that the frequency of flooding has likely doubled in the city over the last century. Meteorologically, the 2022 event also stands out as having recorded the highest-ever 24 hour rainfall amount. However, some aspects of reporting require more critical thought and careful wording.”
Concerns have been expressed that the absence of effective adaptation and mitigation responses will likely escalate the levels of damage associated with floods and related hazards in South Africa.
Construction and maintenance of drainage systems that can cope with large volumes of water and enhanced geotechnical stabilisation of slopes are thus essential adaptation measures, said the study.
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