• The 2022 Durban floods were the most cat

    From ScienceDaily@1:317/3 to All on Tue Apr 11 22:30:22 2023
    The 2022 Durban floods were the most catastrophic yet recorded in KwaZulu-Natal

    Date:
    April 11, 2023
    Source:
    University of the Witwatersrand
    Summary:
    Research shows flooding events in the province have doubled in
    the last century.


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    FULL STORY ==========================================================================
    The disastrous flood that hit Durban in April 2022 was the most
    catastrophic natural disaster yet recorded in KwaZulu-Natal (KZN) in
    collective terms of lives lost, homes and infrastructure damaged or
    destroyed and economic impact.


    ==========================================================================
    This is according to a new study by researchers from the University of
    the Witwatersrand in Johannesburg, South Africa, and the University of Brighton, UK, published in the South African Geographical Journal.

    Professor Stefan Grab from Wits University and his colleague, Professor
    David Nash 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 onwards. They define 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 study, which reconstructed the history of floods in KZN since the
    1840s, confirmed a widely-held -- yet anecdotal view -- that the April
    2022 floods were likely the most catastrophic natural disaster yet
    recorded in KZN and that flooding events have doubled over the last
    century or more.

    "Right after the floods, many commentators like the media, some scientists
    and others were quick to report that the floods were the most severe
    ever recorded.

    Our aim was to place the floods into perspective and see if this and
    other statements related to the disaster were factually correct by
    building a historic geographic account of past floods and associated
    extreme rainfall events for the province of KZN and particularly the
    greater Durban region," says Grab, lead author of the study.

    The scientists found that while the floods were indeed the most
    catastrophic in terms of lives lost, infrastructure damaged, and
    economical loss, the flood was not actually the biggest in terms of
    the area affected, homes destroyed, or the amount of rainfall that fell collectively over a few days.

    "When you look at a natural disaster you need to look at it in
    context. Whether the April 2022 floods were the 'worst in living memory'
    is debatable, as a flooding event in September 1987 affected a larger geographic area of KZN and destroyed more homes than the 2022 event,"
    says Grab. Similarly, a catastrophic flooding event in Durban, 1856 --
    also in April -- produced a greater quantity of rainfall over a three-day period than last year's floods.

    In April 2022, the KZN coastal zone, including the greater Durban area
    and South Coast, received more than 300mm of rain in 24 hours. This led
    to calamitous flooding, with 459 people losing their lives and 88 people
    still missing by the end of May 2022. Over 4000 homes were destroyed,
    40,000 people left homeless, and 45,000 people were temporarily left unemployed. The cost of infrastructure and business losses amounted to
    an estimated US$2 billion.

    In April 1856, 303mm of rain fell in Durban over 24 hours, and a record of 691mm over a three-day period from April 14 to 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, cutting off all communication with other parts of the country. The floods extended inland to Howick and the Umgeni bridge was
    swept away. Over a 16km stretch of beach between the mouths of the Umgeni
    and Umhlanga rivers, 200 drowned oxen were deposited.

    "It is difficult to compare the two floods in terms of which was the most severe. We must recognize that back in 1856 Durban was only a town with a
    much smaller population and economic infrastructure to that of today, and
    thus the percentage of individuals impacted or percentage economic loss
    may well have been greater back in 1856. In addition, coping mechanisms
    and 'outside' support would have been far more restricted during the
    19th century," says Grab.

    It is highly likely that recent anthropogenically-induced global
    climate warming has contributed to trends of increased flooding as we
    have demonstrated here, and this trend is likely to continue so in the foreseeable future.

    However, it is also important to recognize that catastrophic climate
    events such as severe floods are not temporally restricted to a 'warmer
    world' as the 1856 floods happened during a much colder climatic period.

    "With regards flood disasters -- history is repeating itself. We need to prepare for bigger rainfall events in our cities, and that doesn't just
    apply to Durban, it applies to all South African cities and towns. We
    must get our infrastructure, especially drainage systems, in order. It
    is urgent that we better prepare ourselves for the heavy rainfall and
    flood events that are guaranteed to come in times ahead," says Grab.

    The research was funded by The Leverhulme Trust with further support
    from the University of the Witwatersrand.

    * RELATED_TOPICS
    o Earth_&_Climate
    # Floods # Natural_Disasters # Global_Warming #
    Environmental_Issues # Geography # Weather # Water #
    Environmental_Policy
    * RELATED_TERMS
    o Mid-Atlantic_United_States_flood_of_2006 o
    Timeline_of_environmental_events o Gulf_of_Mexico o Levee
    o Coastal_management o Instrumental_temperature_record o
    Meteorology o Temperature_record

    ========================================================================== Story Source: Materials provided by University_of_the_Witwatersrand. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. S.W. Grab, David J. Nash. A new flood chronology for KwaZulu-Natal
    (1836-
    2022): the April 2022 Durban floods in historical
    context. South African Geographical Journal, 2023; 1 DOI:
    10.1080/03736245.2023.2193758 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2023/04/230411105909.htm

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