Browsing by Author "Stuart-Hill, Sabine Ingrid."

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Applying the social-ecological systems framework to understand impacts of flooding in the Palmiet River catchment.
(2021) Dlamini, Londiwe Zola.; Stuart-Hill, Sabine Ingrid.; Sutherland, Catherine Grace.
Accelerating urbanization in African cities is impacting the ability of urban ecosystem services to provide services to contribute to the wellbeing of people. Additionally, climate change presents increased urban risks such as the increased frequency and intensity of flooding. This thereby threatens human life and built infrastructure; and challenges the resilience of communities already strained by socio-economic challenges. Ecosystem services in urban catchments are poorly understood which further adds to the lack of understanding the value of natural resources in urban catchments and subsequently how to restore and protect vital natural resources in order to ensure ecosystem services delivery. The aim of the study is to understand how impacts of flooding decrease the resilience of the communities in the Palmiet River catchment located in Durban, South Africa, through applying the social-ecological system (SES) framework. The Palmiet River catchment is a dynamic and heavily urbanized catchment in which the Palmiet River extends 26km through its headwaters at an elevation of 510m flowing through the lower informal settlement at 18m elevation. The SES framework is an interdisciplinary approach to understanding biophysical and social aspects in a relational landscape – both of which can no longer be studied in isolation. The methodology of the study uses data collected from public community engagement forums to identifyspecific issues occurring within the catchment and understanding the roles of interested and affected stakeholders. Further, aerial photography images of the Palmiet River catchment from 1981 to 2016 were used to identify the rate of urbanization and terrestrial impacts; this data was additionally supported by drone images. A SES framework was applied for sub-sections of the Palmiet River catchment in order to develop a narrative for the total river catchment to improve understanding of societal actions of urbanization that impact the functionality of the Palmiet River. The findings of the study reflect that: 1) Flood events are occurring more frequently, and more peopleare at risk as the influx of people within the catchment increases and the land use/cover changes. 2) A collaborative social system with a strong governance unit exists within the Palmiet catchment. This has facilitated conversations amongst resources users and actorsin the rehabilitation of the resource system. This could potentially serve as a springboard for identifying viable areas for ecological infrastructure investments. 3) The social system has increased resilience within the catchment – however, this may change as flood events continue to increase in intensity and frequency. 4) The Palmiet River is a dynamic social-ecological system that presents challenges as well as opportunities for sustainable and integrative catchment management. The SES framework provided a tool to evaluate the social and ecological systems through which to assess thecurrent limitations for the Palmiet River to regulate flood events. 5) It was lastly necessary to identify ways in which sustainable urban design systems and ecological infrastructure could be used as a part of catchment management strategies to rehabilitate and enhance ecosystem services. It was concluded that the ecosystem services once offered by the Palmiet River catchment have been compromised byunprecedented rates of urbanisation, particularly impacts of growing informal settlements in the lower parts of the catchment as well as industrial areas in the upper parts of the catchment.
An assessment of the water quality of the Baynespruit River and its linkages to the health of the Sobantu community.
(2016) Govender, Jédine.; Stuart-Hill, Sabine Ingrid.
Worldwide, water quality degradation is rife. Rivers are amongst the most susceptible water bodies to this reality. In South Africa, the use of polluted river water for activities such as crop irrigation, washing clothes and recreation, is a common practice in many rural and urban communities. The Baynespruit River, in the province of KwaZulu-Natal, South Africa, is a typical example as it serves as a vital water source to the Sobantu community. There have been numerous reports of extremely poor water quality in this river and suggestions that this may pose health risks to the community. Thus, the aim of this study was to assess the water quality of the Baynespruit River and its linkages to the health of the Sobantu community. This was achieved through analyses of river water quality, river sediment, soil and crop samples, as well as an investigation of the pathways through which community members are exposed to the polluted river and finally, an analysis of urine from a sample of volunteers who are regularly exposed to the river water. The water quality assessment considered pH, electrical conductivity, As, Cd, Cu, Hg, Pb, Zn and E.coli, while the analysis of river sediment comprised of 23 elements including the aforementioned heavy metals. Using microwave acid digestion (EPA 3052) and Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES), soil and crop samples from farming sites in Sobantu were analysed for Cd, Cr, Cu, Pb and Zn, and compared against the South African Water Quality Guidelines for Crop Irrigation. These results showed that E.coli contamination was high, there were extremely low concentrations of the heavy metals apart from infrequent elevated detections of Cu and Pb, as well as infrequent occurrences of acidic water. While the heavy metal concentrations of surface water were low, the sediment analysis suggested elevated concentrations of As, Cd, Cr, Cu, Ni, Pb, Zn, Fe, Mn and Ag. Analyses of soils and irrigated crops showed concentrations of heavy metals in excess of national and international guidelines, respectively. It is suggested that these soil and crop results indicate historical flooding events, which mobilized heavy metals in the river sediments and transferred them onto the floodplain where the farming sites are located. Furthermore, long-term irrigation with low concentrations of heavy metals may have also resulted in the build-up of these contaminants in the soil and eventually the crops. A workshop was held in the Sobantu community which included a questionnaire and separate open-ended conversations conducted with various community members, in order to determine the exposure pathways to the river and the associated health issues of participants. The questionnaire and open-ended conversations indicated that the most common exposure pathways to the river included using river water for crop irrigation, consuming irrigated crops, washing clothes and children swimming in the river. The questionnaire and open-ended conversations also highlighted many cases of skin rashes, as a result of being in direct contact with river water, with one reported case of diarrhoea. The confirmation of the presence of heavy metals in the Baynespruit River and its surrounding environment gave rise to a urine analysis, which used microwave digestion and ICP-OES to determine whether community members who volunteered for the study incurred heavy metal toxicities. However, the analysis did not show any severe cases of heavy metal toxicities to exposed volunteers and the high levels of Pb noted could not be attributed to exposure to the Baynespruit River and/or its surrounding environments, since similar levels of Pb were found in the control volunteers. It was therefore unclear as to whether the health of the exposed people of Sobantu was compromised by heavy metal toxicities. The persistent mention of skin rashes in the questionnaire and open-ended conversations suggests that water-related health issues in the community require further investigation. It was concluded overall that the water quality of the Baynespruit River is severely degraded however, a clear link between this poor water quality and the perceived health issues in the Sobantu community, could not be established. A key recommendation from this study would be for further investigation, i.e. through a detailed health monitoring programme, confirming the health issues that community members have associated with polluted river water.
Development of techniques for the assessment of climate change impacts on estuaries : a hydrological perspective.
(2012) Davis, Nicholas Savile.; Schulze, Roland Edgar.; Kunz, Richard Peter.; Stuart-Hill, Sabine Ingrid.
Global climate change is a naturally occurring phenomenon, influencing weather and climate patterns. However, the greatest cause for concern at present is the rate at which climate change is currently occurring. Natural shifts in climate take place over a period of many thousands of years, not in a matter of decades, which is what is occurring at present. In South Africa, climate change is projected to have different regional effects, which in turn could impact on the components of the terrestrial hydrological system, such as land use. The alteration of the catchment upstream of the estuaries could affect the quantity and quality of streamflows entering estuaries. This could impact negatively upon estuaries, thereby reducing the considerable biodiversity in estuaries and the ecosystems goods and services provided by estuaries which would reduce the significant revenue provided by these systems. The research undertaken in this project investigates the possible effects of climate change, and changes in upstream land use on freshwater inflows into estuarine ecosystems using a daily hydrological model. Owing to the regionality of climate change in South Africa 10 estuaries in different climatic regions were selected for this investigation. Climate output from five GCMs under the SRES A2 climate scenario for the present (1971 – 1990), intermediate (2046 – 2065) and distant future (2081 – 2100) periods was used as input for the selected climate input. Results of these simulations show that the eastern regions of South Africa may experience considerable increases in the occurrence of high intensity rainfall events into the future. This could influence the abiotic factors of the system which may impact upon the biotic components of estuaries, as these systems are physically controlled. In the western regions the difference of the magnitude of flows between present and projected future is minimal. However, projected increases in temperature could influence evaporation, thereby decreasing future flows into estuaries. This, in some instances, may result in systems turning hyper-saline, which could have far reaching implications, both ecologically and economically. Additionally, an investigation, as to the possible effects of irrigation and climate change combined on flows entering and breaching events of the Klein estuary, was undertaken. Hence, simulations including and excluding irrigation routines have been completed. Results from these simulations illustrate the detrimental effects of irrigation into the future periods, especially during 1 in 10 low flow years, when flows into the Klein estuary cease completely. Breaching event results illustrate that climate change could have a negative impact on this estuarine system as the number of events decreases into distant future period. The addition of agricultural abstractions decreases the number of breaching events markedly. Therefore, the link between the marine and terrestrial hydrological systems is lost which could, if this estuary is isolated from the ocean for an extended period of time, become extremely detrimental to the ecological integrity of the Klein estuary. This highlights the value and vulnerabilities of estuarine ecosystems in South Africa to future climate and upstream land use changes.
Exploring the implementation of Integrated Water Resources Management (IWRM) and Adaptive Management (AM) at a local scale: a case study of the uMngeni Catchment, KwaZulu-Natal.
(2020) Awuah, Akosua Kyerewaa.; Trotter, Dayle Carey.; Stuart-Hill, Sabine Ingrid.
Integrated Water Resources Management (IWRM) and Adaptive Management (AM) are internationally recognised approaches to water resource management. IWRM promotes the application of principles such as integration, participation, inclusion, equity, accountability and efficiency which guide the water sector thus creating an enabling environment for practitioners and decision-makers to be more integrated. AM complements IWRM by embracing uncertainty in water resource management attributed to climate change effects and ineffective governance regimes. AM promotes the institutionalisation of social learning within organisations operating in the water sector by incorporating experimental management practices to inform decision-making. The uMngeni catchment in the province of KwaZulu- Natal, South Africa, faces numerous challenges that threaten the availability and quality of water resources. The aim of the study is to assess the institutional aspects that may or may not facilitate the implementation of IWRM and AM and to provide recommendations for effective management. Therefore, a case study approach was utilised to gain an understanding of the implementation of IWRM and AM at the local scale. There were twenty-one semi-structured interviews which were conducted in the Msunduzi Municipality and eThekwini Metropolitan Municipality. A range of environmental, development and water service governance tools were analysed. Through the collected data, several key findings emerge. Firstly, it is evident that the delay in the establishment of an operational Catchment Management Agency (CMA) and the absence of Water User Associations (WUAs) is hindering the implementation of IWRM and AM. Despite the lack of an authoritative body (CMA) and bridging agents as represented by WUAs, role-players in the catchment are actively attempting to improve integration among water users and to address this void. Secondly, the protection and conservation of water resources is governed by the National Water Resources Strategy (NWRS) at a national level and the draft proto-Catchment Management Strategy (CMS) at a regional level. Even with these tools, participants from non-governmental organisations stated that water resources have been managed (regional and national level) for water service provision rather than resource protection. In addition, the overlap and misunderstanding of catchment management roles and responsibilities between municipal departments and private landowners is negatively affecting the degree of integration as well as learning occurring in the catchment. Lastly, most of the participants’ acknowledged the importance of participation and integration, but also indicated that the application of the concept of IWRM is not ideal at the local level particularly in a developing country. Many participants do not understand AM. The limited practice of social learning in the catchment can be attributed to key strategies i.e., CMS not being official, and information sources (e.g., river health reports) not being updated. There is a recommendation to include previously excluded groups into water resources management through the application of the Corporate Social Responsibility (CSR) model. The model will assist in relationship building and fostering partnerships to improve catchment management and to create a culture of accountability and stress the urgency of this for water resource management.
Integrative policy instruments for implementing the National Water Act : a case study of the Mgeni Catchment.
(2013) Vilakazi, Ntombifuthi Pretty.; Stuart-Hill, Sabine Ingrid.
South Africa experienced a paradigm shift with the introduction of the National Water Act in 1998 (NWA). Previously, water resource management was based on a centralized approach. Today, it is framed by the Integrated Water Resources Management approach and rests on the three important principles of equity, sustainability and efficiency. The implementation of these principles is characterized by decentralized decision-making within a framework that brings together all water stakeholders in a new form of communication, particularly those of marginalized groups. However, no matter how clear and ambitious the objectives of the NWA are, the problem of effective implementation remains significant. A mix of centralized and decentralized management instruments, aiming at integrated and adaptive management, has created considerable complexity. This then calls for integrative instruments to allow for greater coordination and enhanced stakeholder participation, in order to produce an integrated management outcome. Although a set of instruments is available under the South African (SA) NWA, these do not seem to be sufficient. Perspectives emerging from a study undertaken in the Mgeni Catchment, using key-informant interviews and household surveys, suggest that this is based on a lack of institutional and management capacity, missing Catchment Management Agencies, limited monitoring and evaluation and lack of integration between the water stakeholders and other sectors that impact on the water resources. Further, it seems that specific elements are creating bottlenecks as well as a loss of responsibility in a decentralized system e.g. the National Water Resource Strategy. This study adopts a social perspective on water resource management and examines the suggestions proposed by water stakeholders in the Mgeni Catchment in relation to major constraints to the implementation process.
Linkages between selected hydrological ecosystem services and land use changes, as indicated by hydrological responses : a case study on the Mpushini/Mkhondeni Catchments, South Africa.
(2014) Schütte, Stefanie.; Schulze, Roland Edgar.; Stuart-Hill, Sabine Ingrid.
Nature provides essential services to humans, including climate regulation, water provisioning and regulation. These so-called ecosystem services have economical, societal and environmental value. This research aims at improving the knowledge on the linkages between selected hydrological ecosystem services and current and proposed land uses within the water-limited Mpushini/Mkhondeni Catchments in South Africa. The research contributes to the recognition of feedback and linkages within the complex ecological-human system, so that informed land use decisions can be made. The research aim is achieved by first reviewing the literature on hydrological ecosystem services, land use in an ecosystem services context and the links between the two. The study area is then sub-delineated into land use determined hydrological response units for baseline natural land cover, as well as for current and proposed land use scenarios. Using an appropriate model, selected hydrological processes are simulated in order to isolate the effects of individual land uses on hydrological responses, both on a local and a more catchment-wide scale. Various land uses were found to affect hydrological responses, such as runoff and its components of stormflows and baseflows, as well as transpiration and sediment yields, differently. These responses were found to be suitable indicators of selected ecosystem services such as water provisioning or flow regulation. Irrigation and high biomass crops, such as sugarcane and wattle plantations were found to reduce downstream water provisioning services. Degraded lands were found to reduce physical water quality through increased sediment yield, to reduce water provisioning during low flow periods, while the degraded lands increased stormflows, thereby reducing regulation of high flows. Urban land uses were found to significantly increase runoff, with increased impervious areas causing a shift from evaporation and transpiration towards runoff. Stormflows increased, with high flow regulation being reduced. Baseflows increased as well, as a result of a spill-over of runoff from impervious to pervious urban areas, which led to increased low flow regulation. In addition, in this study area urban return flows are generated from externally sourced water, further increasing streamflows and especially low flows. While urban areas showed an increase in downstream water quantity provision, the water quality was reduced. The combined effects of the current land use mosaic on the annual streamflows partially cancel each other out, while the proposed urbanisation dominated hydrological responses. Influences of various land uses on hydrological ecosystem services were thereby shown, which contributes to a better understanding of the linkages between the two.
Mainstreaming adaptation to climate change into decision making in the water sector : concepts and case studies from South Africa.
(2015) Stuart-Hill, Sabine Ingrid.; Pahl-Wostl, Claudia.; Schulze, Roland Edgar.
Abstract available in Pdf file.
Projected impacts of climate change on water quality constituents and implications for adaptive management.
(2013) Ngcobo, Simphiwe Innocent.; Jewitt, Graham Paul Wyndham.; Stuart-Hill, Sabine Ingrid.; Lorentz, Simon Antony.; Lumsden, Trevor Graeme.
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.