Philosophiae Doctor - PhD (Earth Science)

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A comparative analysis of long-term variations of temperature and rainfall in rural and urban areas, and their effects on the estimation of design storms in Kenya
(University of the Western Cape, 2016) Gachahi, Lydiah Wangechi; Mazvimavi, Dominic
My Thesis aimed at expanding the current knowledge on how variations of temperature characteristics including the possible existence of urban heat islands (UHI) over urban areas of Kenya could be influencing rainfall characteristics, and to examine if the stationary extreme value distributionis still suitable for modeling urban storm designs in view of the global climate change. My hypothesis was that the floodingoccurring frequently in major urban areas of Kenya are due to increased rainfall caused by global climate change, and the urban heat island (UHI) effect. To put this perception into perspective, temperature and rainfall characteristics and their inter-relationships, of four of the major urban areas in Kenya namely, Nairobi, Mombasa, Kisumu, and Nakuru, were investigated. I obtained data from meteorological stations in and around each urban area, which had at least thirty (30) years of continuous monthly (or daily) temperatures and rainfall values, from the Kenya Meteorological Department. I checked the datasets for quality and missing values and adjusted where necessary before commencing with analysis. I sourced other supporting global dataset from various websites' data banks.I used various methods of data analysis which included; i) exploratory data analysis techniques such as the continuous wavelet transform (CWT), geographical information system (GIS) maps, and visual time series plots. In particular and unique in my Thesis was the use of the CWT method as a diagnostic tool to examine non-stationaritiesand variability of temperature and rainfall time series.
Acid mine drainage prediction techniques and geochemical modelling: case study on gold tailing dams, West Rand, Witwatersrand basin area, South Africa
(University of the Western Cape, 2021) Wu, Changhong; Khotseng, Lindiwe
Acid Mine Drainage (AMD) is identified as one of the contributors to environmental hazard in the gold mining region of South Africa, as caused by the mining operational activities performed by mining industries in South Africa. This effect motivates the development of AMD prediction techniques application and geochemistry modelling using gold tailing dams located in West Rand area, Witwatersrand Basin as a case study. Control strategies are devised to assess, understand and measure the acidic potential generation of waste materials in ensuring the right method required to analyse risks caused by AMD to environment. The method encompasses mineralogical and geochemical analysis of 93 samples collected, AMD prediction, test modification and geochemical modelling. This method was appropriately applied to understand the basic mechanisms involved in controlling acid generation, assessing prediction procedure and selecting the right prediction tools. Study objectives are attained by performing a series of experimental lab tests on the samples collected from the two major tailing dams (Mogale and Gold One_1 tailings). Results derived from the lab experiments (XRD and SEM-EDS) show presence of mineral phases characterised with the surface feature of samples, and unknown substances of samples were identified. Geochemical characterisation was performed by XRF and ICP-MS to determine the major oxides elements and trace elements, respectively. Leco test generate total sulphur and total carbon. Multistatistical analysis is used to interpret the data derived from geochemical characterisation process to explicate the metal and trace elements distribution and occurrence. Initial samples were screened and categorised based on paste pH and EC using kinetic tests to determine acid-forming and neutralising minerals in samples and static tests to determine acid generation potential in samples. Net Acid Producing (NAPP) was mathematically calculated from Acid Neutralising Capacity (ANC), Maximum Potential Acidity (MPA) and total Sulphur. Results obtained from the Paste pH demonstrate that samples collected from 1 meter downward the holes to 10 meters, with a few meters samples in hole T003 at Gold One_1 are non-acidic while the remaining tailing samples are acidic. ANC/MPA ratio was applied to assess the risk of acid generation from mine waste materials. Graphical illustrations of the Acid Base Account (ABA) are plotted to demonstrate the net acidic generation potential trends of samples, which were classified into non-acid forming, potential acid forming and uncertain categories. Results integration between ANC, Single Addition Net Acid Generation (NAG) test and NAPP were used to classify acid generation potential of the samples. Leachate collected from leaching column test were analysed for pH, EC and chemical element by ICP-MS. The leaching column test used to analyse samples (T004) and (T001) collected from the two major tailings was set up for a 4-month experiment. Study findings present environmental assessment report on the two investigated gold tailing dams in Witwatersrand Basin area. Other findings are improved understanding of the application and limitations of various existing AMD prediction methods for assessment of gold mine waste and conceptual geochemical modelling developed to test appropriate methodology for AMD potential at a given gold mine site.
An analysis of sustainability of communally-managed rural water supply systems in Zimbabwe
(University of the Western Cape, 2016) Kativhu, Tendai; Mazvimavi, Dominic
Sustainability of rural water supply systems is a major development challenge in most developing countries including Zimbabwe. This thesis aimed to analyse the sustainability of communally managed rural water supply systems in Zimbabwe. Specifically, it determined the factors influencing sustainability of water supply systems; investigated how the implementation of Community Based Management (CBM) is contributing to the sustainability of water supply systems; explored how multiple uses of water influence sustainability of water supply systems under CBM and determined how the principal factors influencing sustainability and the CBM implementation practices, can be incorporated at the different stages of the development of a water supply system. The study was done in Nyanga, Chivi and Gwanda districts. A total of 399 communally- managed water points were studied and 300 households participated in the study. Questionnaires were used to collect data from households and Water Point Committees (WPCs). Data was also collected using Key Informant Interviews (KIIs) with a total of 33 key informants being drawn from the national, district and community levels.
An integrated approach to understanding the geological controls on gas escape and migration pathways in offshore northern Orange Basin, South Africa.
(University of the Western Cape, 2017) Samakinde, Chris Adesola; Van bever Donker, Jan
The use of an integrated approach in science has gained more prominence recently because it is thorough and provides a dynamic perspective from which scientific problems can be investigated and solutions proffered. Here, an integrated approach (Litho and seismic stratigraphy, structural modelling, Seismic attributes analyses and 3D numerical simulation of hydrocarbon generation and migration) were used to investigate geological controls (faults and stratigraphic features) on hydrocarbon migration pathways and suggest prospective areas within the Block 1 of Orange Basin, South Africa.
Applicability of big data analytics to support groundwater management in Southern Africa
(University of the Western Cape, 2022) Gaffoor, Zaheed; Kanyerere, Thokozani
Groundwater is a vital resources for member states in the Southern African Development Community (SADC). However, sustainable managing groundwater resources in SADC is a challenge. Amongst the many issues facing groundwater managers in SADC, limited access to high fidelity data, as well as a poor understanding of the techniques needed to transform the data into information, has hampered the decision making process. Big data relates to large, voluminous and heterogenous datasets which are being generated through numerous activities, such as computer simulations, remote sensing, commercial transactions, internet activity, monitoring networks, IoT sensors, historical documents, social media and many others.
Application of enviromental and hydrochemical analysis to characterize flow dynamics in the Sakumo Wetland, Ghana
(University of the Western Cape, 2018) Laar, Cynthia; Xu, Yongxin
This research focused on understanding the current hydrogeology of the Sakumo wetland by developing a conceptual flow model and simulating the groundwater flow system. The purpose of the model is to assist in understanding the groundwater flow system and quantify the water fluxes contributing to the wetland water storage. The research adapted quantitative, qualitative and mixed analysis to characterize the water flow in the basin. This involved the use of numerical modelling techniques to determine the zones of groundwater discharge to the wetland and zones of wetland water released for groundwater recharge. Field investigation were carried out to estimate the hydraulic parameters and sample rainwater, wetland water and groundwater. The Sakumo wetland aquifer is situated in the quaternary unit consisting of sandy clay and weathered quartzite. The average annual precipitation in the study area from 1970 to 2016 was estimated at 760 mm/yr. Groundwater recharge rate was estimated as 5% of the mean annual rainfall which provided inputs into the numerical groundwater flow model. Evaporation from the wetland and evapotranspiration from the basin estimated using the Hargreaves and Samani method were 1341 mm/a and 546 mm/a, respectively. The hydrogeologic conceptual model was developed from the geology, borehole lithology, groundwater and wetland water levels.
Application of geochemical characterization, multivariate statistics and geological modelling in assessment and prediction studies on selected coal and gold mine waste in South Africa
(University of the Western Cape, 2023) Abegunde, Oluseyi Blessed; Opuwari, Mimonitu
Over the years, South Africa has generated vast amounts of coal fly ash and gold slime tailings, constituting over 70% of the country's waste materials. These byproducts contain elevated levels of trace metals, posing a potential threat to the environment upon release. Addressing this issue requires a comparative study of the environmental impact of coal fly ash and selected mine tailings on water resources and land pollution. This research aims to investigate and compare leachability, metal release, oxidation effects, and environmental pollution between coal fly ash and gold tailings. By contrasting these aspects, the study seeks to enhance understanding of the potential risks associated with these materials, aiding informed decision-making for their management and regulation. Additionally, the research explores the correlation between gold tailings' acid potential generation and coal fly ash's alkaline potential generation in terms of leachability, metal release, oxidation effects, and environmental pollution. The research employed comprehensive laboratory experiments and analytical investigations, including leaching tests under simulated weathering conditions. A total of 51 gold tailings samples and 66 coal fly ash samples were analysed through SEM and XRD for mineralogical insights and ICP-MS and XRF for geochemical analyses. Statistical analysis revealed the significant roles of pH, Fe ions, Ca2+, and Mg2+ in metal extraction from both materials. Notably, the study identified key factors contributing to the environmental impact of coal fly ash and gold tailings. SEM imagery highlighted heterogeneous characteristics in gold tailings, while factor analysis indicated the potential release of ferrous ionic species, contributing to acidity. Trace elements like Ni, Zn, Pb, and Cu were predominantly associated with Fe/Mn oxides during leaching experiments, facilitating their mobilization with acid-generating ions.
Assessing land use-land cover changes and their effects on the hydrological responses within the Nyangores River Catchment, Kenya
(University of Western Cape, 2021) Ndungo, Margaret Njoki; Mazvimavi, Dominic
This thesis aimed at contributing knowledge on how the widespread changes in land use/cover resulting from increasing human population and their associated activities, are influencing hydrological responses in a sub-humid catchment. The study therefore hypothesised that reduced forest cover over time in favour of agricultural activities is altering hydrological processes of the catchment which is affecting the flow characteristics in a sub-humid catchment. The sub-humid catchment selected to investigate these issues is the Nyangores River Catchment in Kenya.
Assessment of groundwater management for domestic use from IWRM perspective in upper Limphasa river catchment, Malawi
(University of the Western Cape, 2012) Kanyerere, T.; Xu, Yongxin; Saka, John
The research problem for this study is the limited and unsuccessful implementation of the IWRM concept. This thesis has argued that comprehensive assessment of physical and socioeconomic conditions is essential to provide explanation on factors that limit the successful execution of the IWRM approach. It has further argued that the local IWRM works as proxy for full and successful implementation of the IWRM approach.To contextualise this thesis, the prevailing physical and socioeconomic factors in Malawi in relation to current management and usage of water resources were explained.With 1,321m3 per capita per year against index thresholds of 1,700-1,000m3 per capita per year, this study showed that Malawi is a physically water stressed country but not physically water scarce country although economically it is a water scarce country. This novelty is against some literature that present Malawi as a water abundant country.Again, this study showed that executing a full and successful IWRM in Malawi remains a challenge because of the prevailing socioeconomic situation in terms of water policies,water laws, institutions and management instruments. These aspects have not been reformed and harmonised to facilitate a successful operation of the IWRM approach.The main water-related problem in Malawi is the mismanagement of the available water resources. This is largely due to the lack of implementing management approaches which can generate systematic data for practical assessment of water resources to guide the coordinated procedure among water stakeholders working in catchments. This lack of implementing a coordinated management approach commonly known as integrated water resources management (IWRM) can be attributed to various reasons that includei) lack of comprehensive assessment of factors that can explain lack of successful IWRM implementation at catchment level and ii) lack of methods to demonstrate data generation and analysis on quantity, quality and governance of water that show practical operation of IWRM at community level using groundwater as a showcase among others.This study revealed that introducing local IWRM requires a prior knowledge of the evolution and role of the full IWRM concept in the international water policy which aimed at addressing broader developmental objectives. Globally, the current status of the IWRM concept has potential to address such broader developmental objectives, but sustaining IWRM projects where they have been piloted showed slow progress. Basing on the factors that slow such a progress, local IWRM approach has emerged as a proxy to execute the full IWRM as demonstrated in chapter 8 in this thesis. However, the observed lack of sustainable resources to fund continual functioning of local IWRM activities will defeat its potential solution to water management challenges. The main threat for sustainable local IWRM activities is the tendency of national governments to decentralise roles and responsibilities to local governments and communities without the accompanying financial resources to enable the implementation of the local participation, investments and initiatives at local level. If this tendency could be reversed, the contribution by local IWRM towards solving management problems in the water sector will be enormous. Chapter four has provided the general case-study approach used in this study in terms of research design, data collection methods, data analysis methods, ethical consideration and limitation of the current study within the context of water resource management with a focus on groundwater management.Using geologic map, satellite images, photographs and hydrogeologic conceptual model, the following results emerged: 1) that the Upper Limphasa River catchment has fractured rock aquifer with limited permeability and storage capacity; 2) The topographic nature and north-south strikes of the lineaments explained the north-south flow direction of groundwater in the catchment; 3) The drainage system observed in the Kandoli and Kaning’ina Mountains to the east and west of the Upper Limphasa River catchment respectively (Fig. 5.1; Fig.5.2) formed a groundwater recharge boundary; 4)The regional faults in the same mountains (Fig. 5.1; Fig.5.2) formed structural boundar as well as hydrogeologic boundary which controlled flow direction of the groundwater;5) the hydrogeologic conceptual model showed the existence of the forested weathered bedrock in the upland areas of the entire catchment which formed no-flow boundary and groundwater divide thereby controlling the water flow direction downwards (Fig. 5.9);6) The major agricultural commercial activities existed in Lower Limphasa catchment while only subsistence farming existed in Upper Limphasa catchment. This knowledge and visualization from the map (Fig. 5.3) and conceptual model (Fig.5.9) showed interactions between upland and lowland areas and the role of physical factors in controlling groundwater flow direction in the catchment. It also provided the enlightenment on implications of socioeconomic farming activities on water management. These insights enabled this study to recommend the need for expedited implementation of holistic effective management for sustainable water utilization.Using different physical factors, water scarcity indices and methodologies, this study showed that Malawi is a physically water stressed as well as an economic water scarce country. This novelty is against some literature that present Malawi as a water abundant country. Again, despite the high proportion (85%) of Malawians relying on groundwater resource, groundwater availability (storage in km3) is relatively low (269 km3 in Table 6.10) compared to other countries within SADC and Africa. Given the complexity of groundwater abstraction, the available groundwater for use is further reduced for Malawians who depend on such a resource for their domestic and productive livelihoods. Such insights provided the basis for discussing the need for IWRM.Although daily statistics on groundwater demand (i: 21.20 litres; 116.91 litres;80,550.99 litres), use (ii: 16.8 litres; 92.55 litres; 63,766.95 litres) and abstracted but not used (iii: 4.4; 24.36; 16,784.04 litres) were relatively low per person, per household and per sub-catchment respectively, such statistics when calculated on monthly basis (i.Demand: 636 litres; 3,507.30 litres; 2,416,529.70 litres; ii.Use:504 litres; 2,776.5 litres;1, 913, 008.5 litres iii. Abstracted but not used: 132 litres; 730 litres; 503, 521.2); and on yearly basis (i. Demand: 7,632 litres; 42,087.6 litres; 28,998,356.4 litres; ii. Use: 6,048 litres; 33,318 litres; 22, 956, 102 litres; iii: Abstracted but not used: 1,584 litres; 8,769.6 litres; 6,042,254.4 litres) per person, per household and per sub-catchment provided huge amount of groundwater (Table 6.5). Given the limited storage capacity of fractured rock aquifer in the basement complex geology, the monthly and yearly groundwater demand and use on one hand and abstracted but not used on the other was considered enormous. With the population growth rate of 2.8 for Nkhata Bay (NSO, 2009) and the observed desire to intensify productive livelihoods activities coupled with expected negative effects of climate change, the need to implement IWRM approach for such groundwater resource in the study catchment remains imperative and is urgently needed.In addition to identifying and describing factors that explain the limited groundwater availability in the study catchment, the study developed a methodology for calculating groundwater demand, use and unused at both households and sub-catchment levels.This methodology provided step-by-step procedure for collecting data on groundwater demand and use as a tool that would improve availability of data on groundwater.Implications of such results for IWRM in similar environments were discussed. Despite the time-consuming procedure involved in using the developed methodology, the calculations are simple and interpretation of results is easily understood among various stakeholders. Hence, such an approach is recommended for the IWRM approach which requires stakeholders from various disciplines to interact and collaborate. Nonetheless, this recommends the use of this method as its further refinement is being sought. The analysis on groundwater quality has shown that the dominant water type in the aquifers of Upper Limphasa catchment was Ca-HCO3, suggesting that the study area had shallow, fresh groundwater with recent recharged aquifer. Analyses on physicochemical parameters revealed that none of the sampled boreholes (BHs) and protected shallow dug wells (PSWs) had physical or chemical concentration levels of health concern when such levels were compared with 2008-World Health Organisation(WHO) guidelines and 2005-Malawi Bureau of Standards (MBS). Conversely, although the compliance with 2008-WHO and 2005-MBS of pathogenic bacteria (E.coli) in BHs water was 100% suggesting that water from BHs had low risk and free from bacteriological contamination, water from PSWs showed 0% compliance with 2008-WHO and 2005-MBS values implying high risk to human health. The overall assessment on risk to health classification showed that PSWs were risky sources to supply potable water, hence the need to implement strategies that protect groundwater.On the basis of such findings, the analysis in this study demonstrated the feasibility of using IWRM approach as a platform for implementing environmental and engineering interventions through education programmes to create and raise public awareness on groundwater protection and on the need for collaborative efforts to implement protective measures for their drinking water sources. The use of different analytical methods which were applied to identify the exact sources of the observed contaminants in the PSWs proved futile. Therefore, this study concluded that rolling-out PSWs either as improved or safe sources of drinking water requires further detailed investigations.However, this research recommended using rapid assessment of drinking water-quality (RADWQ) methods for assessing the quality of groundwater sources for drinking. Despite the study area being in the humid climatic region with annual rainfall above 1,000 mm, many of the physical factors were not favourable for availability of more groundwater in the aquifers. Such observation provided compelling evidence in this study to commend the local IWRM as a proxy for the full IWRM implementation for sustainable utilization of such waters. Although institutional arrangements, water laws and water policy were found problematic to facilitate a successful implementation of full IWRM at national level in Malawi, this thesis demonstrated that local institutional arrangements, coordination among institutions, data collection efforts by local community members (active participation), self-regulation among local community committees were favourable conditions for a successful local IWRM in the Upper Limphasa River catchment. This research recommends continuation of such local participation, investment and initiatives as proxy for the full and successful IWRM beyond the study catchment. However, the observed lack of financial resource from central government to facilitates local IWRM activities were seen as counterproductive.In addition, this thesis recommended further studies which should aim at improving some observed negative implications of self-regulations on community members and the limited decentralisation elements from the Department of Water Development.Finally, one of the contributions from this study is the scientific value in using different methods to assess the quality of groundwater as presented in chapter 7. The second value is the demonstration of applying practical techniques to evaluate factors that explain the amount of groundwater storage in the aquifers that can be understood by water scientists, water users, water developers and water managers to implement IWRM collaboratively using groundwater as a showcase. The third contribution is the provision of the procedure to systematically generate data on demand (abstraction) and use of groundwater in unmetered rural areas which has the potential to guide water allocation process in the catchment. Fourthly, the thesis has provided a hydrogeologic conceptual model for the first time for Limphasa River catchment to be used as a visual tool for planning and developing management practices and addressing current water problems.Fifthly, the study has shown how local IWRM works at community level as a proxy for the full implementation of IWRM despite the absence of Catchment Management Agencies. The last contribution is the dissemination of results from this study made through publications and conference presentations as outlined in the appendix.
Assessment of managed aquifer recharge using GIS based modeling approach in West Coast, South Africa
(University of the Western Cape, 2019) Zhang, Heng; Xu, Yongxin
Due to climate change, rapid urbanization, and population expansion, the water demand and supply is showing increasing fluctuations, especially in the arid or semi-arid regions. One of the most important water resource management strategies to improve water security in these drought-prone areas is managed aquifer recharge (MAR), which is developed to recharge groundwater purposefully and increase its storage to overcome the temporal imbalance between local water demand and availability, thus improving water security of the water supply. Assessment of an MAR project requires the integration of many types of methods, data and information from many disciplines, which makes it a challenge. This thesis addressed a GIS based modeling approach for assessing the implementation of MAR in terms of suitable sites as well as appropriate scheme in drought-prone area. The West Coast of South Africa was studied as a case. Langebaan Road
Assessment of sustainable groundwater utilization with case studies from semi-arid Namibia
(University of the Western Cape, 2016) Sarma, Diganta; Xu, Yongxin
The thesis addresses sustainability of groundwater utilization in arid and semiarid regions of Namibia. Recharge in this hydrogeological setting occurs as discrete events to aquifers that are bounded in extent. Case studies involving fractured hardrock and alluvial aquifers with aquifer-ephemeral river interaction were considered. The nature of recharge to arid region bounded aquifers was explored. In arid region aquifers, roundwater storage is depleted during extended dry periods due to pumping and natural discharge. Steady state conditions are rarely achieved. With lowering of the water table, evapotranspiration is reduced thus decreasing aquifer discharge. However, depletion of ephemeral river flow is the primary source of water to boreholes. Physical constraints such as river bed and aquifer hydraulic properties set a limit to the degree of natural replenishment possible during flow events. An approach to assessing sustainable yield of a fractured rock aquifer associated with ephemeral river flow is discussed using a case study from rural semi-arid Namibia. Limited data required the simulation results to be verified against geological and hydrogeological constraints. The aquifer’s gain in storage is estimated through numerical simulation. It provides a basis for groundwater scheme management that rely on limited data in semi-arid conditions in sub-Saharan Africa. Aspects related to ephemeral river flow and groundwater recharge to strip alluvial aquifers was addressed in the second case study. The processes controlling infiltration, significance of surface water and groundwater losses, and possible artificial recharge options were investigated through numerical simulation. It was concluded that recharge processes in arid alluvial aquifers differ significantly from those in humid systems. Conjunctive use of surface and groundwater resources require artificial augmentation of aquifer recharge due to constrains in natural infiltration rates. The study provides a reference for sustainable management of alluvial aquifer systems in similar regions. It is seen from the study that high rates of groundwater exploitation deplete surface water resources needed downstream while failure to capture surface flow during flood events cause loss of potential recharge. It is concluded that as water demand in Namibia increases, basin wide combined surface water and groundwater resource evaluation and management have become a necessity.
An assessment of the influence of water allocation on sustainable water resources management: A case study of the Nyando river basin, Kenya
(University of the Western Cape, 2018) Sungu, Ronald O.; Mazvimavi, Dominic
Water problems prevalent in the Nyando River Basin are due to an ineffective water allocation system and lack of adequate conditions for implementation of sustainable integrated water resources management (IWRM) strategies. The basin is bedevilled by poor water resources management, inequitable allocation of water among consumers, physical infrastructural deficiencies, inefficient water utilisation, illegal water abstractions, natural resource mismanagement, conflicting and weak institutional roles and lack of stakeholder involvement in water resource management. The results of the study reveal sufficient per capita annual water availability with the potential to realise both Sustainable Development Goals (SDGs) and the Kenyan Vision 2030. However, analyses from flow duration curves (FDCs) and the water evaluation and planning (WEAP) model show that monthly water demands including environmental flow requirements (EFRs) are met only between 43% and 94% of the time. While the Water Act (2002) upholds the principles of IWRM on equitable and sustainable water resources allocation, in practice the current water allocation system falls short of implementing these strategies due to lack of a water allocation plan (WAP), inadequate water demand management (WDM), low infrastructural development and lack of community participation in WRM. For example, the total revenue generated in water supply schemes is only about 25 to 30% of their operational costs, which means that in the absence of subsidies the schemes cannot operate. The goal of this study was to examine the influence of the current water allocation system on water resources management in the Nyando River Basin by comparing the various sectoral water demands in the basin with the available water resources in order to improve understanding of how water allocation systems work in practice. The analyses further revealed that irrigation uses up to 72% of the available water, which is mainly drawn from the regular low flow contrary to the permit order. For example, the Ahero National Irrigation Scheme is permitted to draw 47 m3/day of water from regular flow and 13,500 m3/day from flood flow, but draws the whole amount from the regular flow; hence irrigation is the main cause of water deficits in the basin. Projections show that the irrigation sector will experience 300% increase in an unmet demand of 92.4 Mm3 by 2030 up from the current annual deficit of 2.9 Mm3. In light of the above challenges, both improvement of WDM and infrastructural provision have complementary roles in contributing to sustainable water availability, socioeconomic growth and poverty eradication in the basin and help achieve SDGs at the local scale. The results of the study will facilitate an understanding of the influence of water allocation systems on regional hydrology and form the basis of improving water allocation systems, and inform policy formulations to ensure sustained water availability and environmental sustainability in river basins. In that regard, this study contributes to the on-going global debate on Sustainable Development Goals by exploring ways of realising and improving IWRM strategies and the National targets.
An assessment of water use by riparian and non-riparian invasive alien plants and the effects on water resources at the catchment scale
(University of the Western Cape, 2023) Mkunyana, Yonela Princess; Mazvimavi, Dominic
The diversity and increasing extent of invasive alien plants (IAPs) are currently a global ecological and economic problem, especially in semi-arid regions. The introduction of IAPs worsens the strain in South Africa’s water resources by reducing the mean annual runoff by approximately 7%. Further work needs to be done to ensure that those IAPs that have the greatest impact receive priority. Effective management of IAPs promotes the conservation and sustainable use of the natural environment, the economies it supports, and the high quality of life in society. The monitoring of the distribution of IAPs is therefore an important consideration in catchment management. Remote sensing and cloud computing platform, Google Earth Engine (GEE) were used to map land use/landcover changes between the 1973 – 2021 period using Landsat imagery.
Characterization of flowpaths to improve the prediction of vegetation impacts on hydrological processes in semi-arid mountainous catchments of the Cape Fold Belt
(University of Western Cape, 2021) Jumbi, Faith Tatenda; Mazvimavi, Dominic
Mountainous areas are important water sources in many landscapes. An understanding of how mountainous catchments function is important particularly in semi-arid areas, where water shortages are prevalent. In addition to climate and physiographic factors, the hydrological responses of mountainous catchments can be influenced by land uses and land cover types. Although the general effects of land use and land cover types on hydrological processes are known, prediction of the specific effects in a given catchment is still problematic. This study characterized flowpaths, and hydrological responses to different land cover types in a semi-arid, mountainous Kromme River catchment (Eastern Cape province of South Africa), located in the Cape Fold Mountains of the Table Mountain Group (TMG) geological region.
Citizen participation and water services delivery in Khayelitsha, Cape Town
(University of the Western Cape, 2011) Nleya, Ndodana; Thompson, Lisa; School of Government
This study analyses the relationship between the manner of citizens’ engagement with the state and the level of service delivery they experience in their everyday lives, as residents of Khayelitsha. The phenomena of so-called ‘service delivery’ protests across South Africa have now become a fixture of South African politics. Khayelitsha is one of the sites with frequent protests in Cape Town and is inhabited by poor people, 70 percent of whom live in informal settlements. While the lack of municipal services is undoubtedly a major problem for many poor people in South Africa, thus far, few studies have been dedicated to investigate empirically this alleged link between service delivery and protest activity. The study utilizes mostly quantitative analysis techniques such as regression analysis and path analysis to discover the form and strength of linkages between the service delivery and participation forms. While residents of informal settlements and therefore poorer services were more prone to engage in protests and thus reinforcing the service delivery hypothesis, this relationship was relatively weak in regression analysis. What is more important than the service delivery variables such as water services was the level of cognitive awareness exemplified by the level of political engagement and awareness on the one hand and level of community engagement in terms of attendance of community meetings and membership of different organizations. In summary the study found relatively weak evidence to support the service delivery hypothesis and stronger evidence for the importance of cognitive awareness and resource mobilization theories in Khayelitsha as the key determinant of protest activity.
Constraints on the genesis of the Sandamap gold prospect, Namibia: fluid inclusion, geochronology and stable isotope studies
(University of the Western Cape, 2020) Siseho, Kamwi Rector; Russell, Bailie; Greyling, Lynnette
The Sandamap gold prospect is a metaturbidite shear zone-hosted gold mineralization located in the Neoproterozoic Damara Orogen 30 km northwest of the town of Usakos in Namibia with an estimated gold content of 240 000 t at 3.6 g/t up to 40 m below surface. This research project was aimed at constraining the age, crustal level of formation, pressure-temperature conditions during formation, sources of the mineralizing fluids, and by implication, the metal sources of the Sandamap gold mineralization. Fluid inclusion, geochronological and isotopic studies were carried out on quartz veins hosting the ore. The presence of kaolinite, alunite and jarosite suggest post-hydrothermal weathering of sulfides. Various sources of data from this study, giving rise to depths of entrapment of 4 to 14 km, temperature range of entrapment of fluids of 187 – 594 °C, stable isotope data (δ13C and δ18O), δD values and a δD vs. δ18OH2O plot are all in favour of an orogenic gold deposit. Additionally, the dominant CO2-rich and CH4-rich fluids observed at Sandamap do not contradict this interpretation. The calculated depth of entrapment of mineralization covers the lower portion of the epizonal zone to the upper portion of the hypozonal zone of gold deposits. The Sandamap mineralization’s δD values of -35‰ to -49‰ fall within the range of most published data for typical orogenic gold deposits which varies from -20 to -80‰. Moreover, the calculated δ18Owater values of the ore-fluids (+6.6 to +11.3‰) of the higher temperature aqueous group from the Sandamap mineralization fall within the range observed in typical orogenic gold deposits found in Phanerozoic terrains (+7 to +13‰). The schist hosting the mineralized shear zone with a gold content of 0.05 ppm Au or its higher grade equivalent at depth, is a possible gold source candidate. Two mechanisms of deposition were possibly at play: (i) the cooling below 500 °C and possible sulfidation (resulting from fluid-rock interaction), lowered the solubility of pyrite causing S3- and Au(HS)S3- (possible main Au carriers) to breakdown resulting in decreased Au solubility and its subsequent deposition and (ii) the elevated amount of CO2 (e.g. trench 14 where CO2-rich fluid inclusions are dominant) led to a sharp decrease in the Au(HS)2- and Au(HS)S3- concentrations, causing decreased Au solubility and its subsequent deposition. The age of mineralization obtained from 40Ar/39Ar dating of the muscovite associated with the ore-hosting quartz veins is placed at 472 ± 3 Ma. The mineralization is younger than the shear zone, which acted as a conduit for ore-fluid migration and it has no age relationship with proximal plutonic bodies. The mineralization is younger than the foliated granite (FG), which exhibits a metamorphic fabric in the form of mineral segregation, but older than the non-foliated granite (GT) which hosts a mineralized xenolith.
A decision-making framework for groundwater management in arid zones (with a case study in Namaqualand).
(University of the Western Cape, 2004) Pietersen, Kevin Claude; Xu,Yangwin and Green, George Clifford
The main aim of the work on which this thesis is based was to develop a framework for sustainable management of groundwater resources in arid zones with emphasis on Namaqualand in the north western region of South Africa. The first part of the thesis focuses on describing the groundwater resource base and legislative framework for groundwater management. Most aquifers in South Africa occur in fractured rock ranging in age from earliest Pre-Cambrian to Jurassic. Primary aquifers are mostly restricted to the coastal plains and river deposits. Characterisation of the fractured rock aquifers has been limited. Thus, an inadequate knowledge base exists in a number of hydrogeological domains to understand the attributes and dynamics of fractured rock aquifers. A serious shortcoming in our knowledge base is to understand the institutional arrangements necessary for proper resource management. This is particularly important in view of the National Water Act of 1998, where groundwater is subject to the same protection measures as surface water. These measures are sophisticated and require tools and technologies to be developed to support sustainable groundwater management and utilisation. The technical, economic, social, legal, political, and environmental issues affecting groundwater management of arid zones of South Africa were analysed. The objectives and appropriate measures to overcome the barriers for sustainable development were also presented. This was necessary to structure the decision problem and to generate and identify the decision alternatives. Thus decision alternatives have been formulated for the various elements of the objectives in order to achieve preferred scenarios. The main part of the thesis was the development of a decision-making framework for groundwater management in the arid zones of Namaqualand. A multiple criteria decision analysis (MCDA) approach was adopted to assist in the formulation of the decision-making framework. ln order to select the most appropriate MCDA technique, some background was required on the theoretical aspects. A value function method was selected, which provides decision support by interval SMART/SWING. This method incorporates informational uncertainty through interval judgements. The decision problem supported the selection of this method because of the discrete alternatives and uncertainty associated with groundwater management. Further, the method provided an interactive technique to interrogate various decision alternatives based on prior knowledge of the decision-maker. The software WINPRE was utilised in the value tree construction and analyses, A number of value trees and attributes were defined. These attributes were evaluated against the identified alternatives. This provided a systematic framework for the analytical understanding of the problem. As a result a number of preferred alternatives were elicited. The analyses resulted in a model for groundwater management in arid zones. The ideal state for groundwater management was presented, but in practice this is difficult to implement, mainly because of human and financial resources. As a result, a critical path was established based on the analyses done in this thesis. This was applied to the Namaqualand example. ln this example the activities to support a Catchment Management Strategy was identified. This means that the decision-maker is able to focus on issues that are deemed important. More importantly, the method allows the decision-maker to develop the various consequences of the alternatives with stakeholders. As a result of the decision model a number of strategies were proposed for sustainable groundwater management in arid zones with a case study in Namaqualand. A consequences table were developed which could be used for M&E purposes.
Developing a citizen science framework for water resources Protection to facilitate operationalization of resource Directed measures at catchment level, South Africa
(2021) Nzama, Stanley Mvuselelo; Kanyerere, Thokozani
Maintenance of water resources protection practice for water availability, uninterrupted water utilization, and for ecosystem integrity is critical for sustainable achievement of resource security for all. Therefore, operationalization of water resource protection strategies such as resource directed measures, especially at catchment level where water resources utilization takes place is critical. The main aim of the current study was to develop a citizen science framework for operationalization of resource directed measures at catchment level. Such a framework used a nexus approach, and its development was guided by the principles of socio-ecological model from a systems thinking perspective. This demonstrated importance of resource directed measures which are accepted as relevant policy implementation strategies towards improved and integrated water resources management practice at catchment level, where local citizens become part of such practice. Local operationalization of resource directed measures provides a basis for practical policy implementation at catchment level, thereby informing decisions taken on water resources protection and sustainable water use for several purposes. It provides an understanding of how policies which are formulated for water resources protection purposes influence land use activities and other non-land use activities to ensure water availability for current and future generations. Furthermore, localized operationalization of resource directed measures facilitates ecological ecosystems protection such that goods and services derived from such ecosystems are sustained. The research problem of the current study was a lack of available and feasible plan for resource directed measures practice at catchment level which has a direct influence on the continued water quality deterioration and unsustainable utilization of water resources. This study argued that a citizen science framework needed to be developed and such a plan must be informed by science-policy interface that is practical, reflective and must consider the nexus approach using the concept of citizen science in order to improve the practice of resource directed measures at local level in an acceptable manner by practitioners.
Developing a citizen science framework for water resources protection to facilitate operationalization of resource directed measures at catchment level, South Africa
(University of Western Cape, 2021) Nzama, Stanley Mvuselelo; Kanyerere, Thokozani
Maintenance of water resources protection practice for water availability, uninterrupted water utilization, and for ecosystem integrity is critical for sustainable achievement of resource security for all. Therefore, operationalization of water resource protection strategies such as resource directed measures, especially at catchment level where water resources utilization takes place is critical. The main aim of the current study was to develop a citizen science framework for operationalization of resource directed measures at catchment level. Such a framework used a nexus approach, and its development was guided by the principles of socio-ecological model from a systems thinking perspective. This demonstrated importance of resource directed measures which are accepted as relevant policy implementation strategies towards improved and integrated water resources management practice at catchment level, where local citizens become part of such practice.
Developing an integrated remotely sensed framework for the detection and monitoring of seasonally-flooded wetlands in semi-arid environments of southern Africa
(University of the Western Cape, 2022) Gxokwe, Siyamthanda; Dube, Timothy
Wetlands are among the most important ecosystems on earth; they cover approximately 4-6% of the earth’s surface and offer critical eco-hydrological services. However, these ecosystems are under threat from anthropogenic activities, droughts and climate variability, as well as from global environmental change. It is estimated that over 60% of the world’s wetlands have been lost due to climate change and variability, as well as other anthropogenic influences. There is, therefore, a need for their routine monitoring and assessment to ensure the sustainable use and management of these systems on a national, regional and local scale, and prevent their further degradation and loss. This study aimed at developing an integrated cloud-computing-based, remotely-sensed framework for the detection and monitoring of small and seasonally-flooded wetlands along the semi-arid Limpopo Transboundary River Basin of southern Africa, which was previously a challenging task when using the traditional assessment and monitoring methods.

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