Assessing the Impact of Anthropogenically Modified Land Uses on Wetland Health: Case of Witbank Dam Catchment in South Africa

Mpandeli, Sylvester, Liphadzi, Stanley, Mabhaudhi, Chengetanai, Mabhaudhi, Tafadzwanashe and Nhamo, Luxon, (2024). Assessing the Impact of Anthropogenically Modified Land Uses on Wetland Health: Case of Witbank Dam Catchment in South Africa. Water, 16(6), 2287-n/a

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  • Sub-type Journal article
    Author Mpandeli, Sylvester
    Liphadzi, Stanley
    Mabhaudhi, Chengetanai
    Mabhaudhi, Tafadzwanashe
    Nhamo, Luxon
    Title Assessing the Impact of Anthropogenically Modified Land Uses on Wetland Health: Case of Witbank Dam Catchment in South Africa
    Appearing in Water
    Volume 16
    Issue No. 6
    Publication Date 2024-08-13
    Place of Publication Basel, Switzerland
    Publisher MDPI
    Start page 2287
    End page n/a
    Language eng
    Abstract Wetlands are critical ecological infrastructures that improve water quality, serve as habitat for fish and other aquatic life, accumulate floodwaters, and maintain surface water flow during dry periods. However, the health of wetlands has been compromised by anthropogenic activities that affect the constant supply of ecosystem services. This study assessed the impact of anthropogenically modified land use on wetland health in the Witbank Dam Catchment in South Africa, whose land use has been severely modified for agriculture and mining purposes. The study developed a model linking surface runoff generated in the catchment with land use and wetland typology to comprehend diffuse pollution from pollution-source land uses. Runoff data and related wetland spatial information were processed and analysed in a Geographic Information System (GIS) to estimate pollutants (agricultural nutrients and acid mine drainage) from runoff detained and released by wetlands. The analysis facilitated the assessment of the value of wetlands in enhancing water quality, as well as human and environmental health. The runoff volume from pollution-source land uses (urban areas, farmlands, and mining) was used to evaluate annual pollution levels. Wetland types are ranked according to their efficiency levels to filter pollutants. The assumption is that the difference between filtered and unfiltered runoff is the quantity of polluted runoff water discharged into the river system. The analysis has shown that 85% of polluted runoff generated in the catchment ends up in the river system. An important observation is that although wetlands have a substantial ability to absorb excess pollutants, they have finite boundaries. Once they reach their full holding capacity, they can no longer absorb any further pollutants. The excess is discharged into the river system, risking human and environmental health. This explains why the Limpopo River is heavily polluted resulting in the death of fish, crocodiles and other aquatic life.
    Keyword Water quality
    Filtration
    Land use
    Wetland functions
    Nonpoint source pollution
    Copyright Holder author(s)
    Copyright Year 2024
    Copyright type Creative commons
    DOI https://doi.org/10.3390/w16162287
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    Created: Wed, 23 Oct 2024, 05:50:14 JST by Haideh Beigi on behalf of UNU INWEH