The past few decades have seen, amongst other topical environmental issues, increased
concerns regarding the imminent threat of global warming and the consequential impacts of
climate change on environmental, social and economic systems. Numerous groundbreaking
studies conducted independently and cooperatively have provided abundant and conclusive
evidence that global climates are changing and that these changes will almost certainly
impact natural and socio-economic systems. Increased global change pressures, which
include, inter alia, climate change, have increased concerns over the supply of adequate
quality freshwater. There is an inadequate body of knowledge pertaining to linking basic
hydrological processes which drive water quality (WQ) variability with projected climate
change. Incorporating such research into policy development and governance with the
intention of developing adaptive WQ management strategies is also overlooked. Thus, the
aim of this study was the assessment of projected climate change impacts on selected WQ
constituents in the context of agricultural non-point source pollution and the development of
the necessary adaptation strategies that can be incorporated into WQ management, policy
development and governance. This assessment was carried out in the form of a case study in
the Mkabela Catchment near Wartburg in KwaZulu-Natal, South Africa. The research
involved applying climate change projections derived from seven downscaled Global
Circulation Models (GCMs) used in the Fourth Intergovernmental Panel on Climate Change
(IPCC) Assessment Report, in the ACRU-NPS water quality model to assess the potential
impacts on selected water quality constituents (viz. sediment, nitrogen and phosphorus).
Results indicated positive correlations between WQ related impacts and contaminant
migration as generated from agricultural fertilizer applications. ACRU-NPS simulations
indicated increases in runoff and associated changes in WQ variable generation and migration
from upstream sources in response to downscaled GCM projections. However, there was
limited agreement found between the simulations derived from the various downscaled GCM
projections in regard to the magnitude and direction (i.e. percent changes between present
and the future) of these changes in WQ variables. The rainfall distribution analyses conducted
on a daily time-step resolution for each selected GCM also showed limited consistency
between the GCM projections regarding rainfall changes between the present and the future.
The implication was that since hydrological and climate change modelling can inform
adaptation under climate change. However, adaptation to climate change in water quality
management and policy development is going to require approaches that fully recognise the
uncertainties presented by climate change and the associated modelling thereof. It was also
considered crucial that equal attention be given to both climate change and natural variability,
in order to ensure that adaptation strategies remain robust and effective under conditions of
climate change and its respective uncertainties. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/9480 |
| Date | January 2013 |
| Creators | Ngcobo, Simphiwe Innocent. |
| Contributors | Jewitt, Graham Paul Wyndham., Stuart-Hill, Sabine I., Lorentz, Simon A., Lumsden, Trevor Graeme. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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