OpenUCT :: Browsing by Author "Winter, Kevin"

Browsing by Author "Winter, Kevin"

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Open Access
A bio-indicator assessment towards the rehabilitation of the Stiebeuel River, Franschhoek, South Africa
(2019) Cameron, Kieran; Winter, Kevin
Increased urbanization coupled with the effects of urban stream syndrome and urban informal settlements are degrading rivers and causing a decline in habitat integrity and the delivery of ecosystem services. There is a need to implement river restoration programmes to alleviate the negative impacts on stream ecosystems. This study aimed to determine the ability of a contaminated urban stream, draining Langrug, an informal settlement, to enrich the biodiversity of species and organisms, following a rehabilitation intervention. It was investigated how nature, in the form of biodiversity of diatoms and macro-invertebrates, were observed in the Stiebeuel River when a range of habitats were created and restored through the replanting of indigenous vegetation within the Stiebeuel River channel. The focus of the study is on understanding the value of different types of bio-assessment and water quality methodologies for informing the rehabilitation of a river system. It also illustrates how a combination of methods as opposed to a single method is able to inform the ecological integrity of habitat restoration.The results showed the current physical and biological condition of the Stiebeuel River to be heavily degraded, critically modified, with poor river health and an ecological category between D and E/F. The low DO levels and high EC levels are correlated to low SPI scores and high %PT scores, which infers that there is a significant amount of organic pollution and nutrients in the wastewater discharges from Langrug, informal settlement. The miniSASS scores link to the SPI scores, such that the low sensitivity and low SPI scores are attributed to the highly polluted water quality dictating the abundance of pollutant tolerance species. The inflow of highly polluted water from Langrug, informal settlement is responsible for driving the distribution of species in the Stiebeuel River. This highly contaminated water as a result restricted the success of the habitat intervention to enrich biological diversity and improve the ecological status of the Stiebeuel River. The results from the bio-assessment and water quality monitoring overlap and confirms the link between the three monitoring methods
Open Access
Adult conceptions of the environment: an analysis of a formal curriculum in Environmental Education
(1996) Reddy, Shaada; Morphet, Tony; Winter, Kevin
This research reports on an evaluation of conceptions of the environment held by a group of students at the University of Cape Town. This group of students were all registered for the degree of Bachelor of Education, and included in their curricula the elective in Environmental Education. The research attempts to describe the constructivist approach as implemented in the course in Environmental Education over a prescribed period, and to explore the impact of such an approach on student conceptions. The research was conducted primarily through the use of two questionnaires together with unstructured interviews. The results of the questionnaires and interviews were used to assess both qualitatively and quantitatively the development of student conceptions of the environment. The first questionnaire was administered early on in the course, while the second was administered towards the end of the course. In this way it was possible to make a comparative study of the responses. The results indicate that the course contributed to some shift in student conceptions of the environment, and that it contributed also towards the development of environmental attitudes, values and behaviour. The work concludes with suggestions for developing aspects of the course design, in the light of insights gained by this research.
Open Access
An analysis of discharge and water quality of an urban river and implications for stormwater harvesting
(2020) Aziz, Fahad; Winter, Kevin
Development in urban catchments often result in rivers being converted into large stormwater canals where stormwater is removed as quickly as possible to prevent flooding. A combination of elevated peak flows, increased nutrients and contaminants and reduced biotic richness are typical features of these urban waterways. This study explored the dynamics of an urban river in Cape Town by using high-resolution monitoring sensors and loggers to analyse and model real-time discharge and water quality data during and after 14 rainfall events. Discharge and water quality data were collected from the Liesbeek River at three sites during the rainfall events. As expected, the upper most sampling site had the lowest discharge and pollution load, compared to sites in the middle and lowest reaches of the river. An analysis showed significant correlations between the discharge and electrical conductivity at all three sampling sites. Rainfall was the primary factor in altering discharge and electrical conductivity. Predictive modelling using selected rainfall designs indicated that average discharge and total volume increases with increasing rainfall. Linear regression analysis for electrical conductivity indicated a strong relationship whereby an increase in discharge resulted in a decrease in electrical conductivity. This study revealed the discharge and water quality of stormwater in the Liesbeek River during rainfall events showed the improved water quality conditions in the river during the rainfall events particularly after the peak discharge. Furthermore, the implications of this study revealed that the Liesbeek River can become a water source for recharging groundwater and aquifers.
Open Access
An analysis of nature-based treatment processes for cleaning contaminated surface water runoff from an informal settlement: a case study of the Stiebeuel River catchment, Franschhoek, South Africa
(2022) Nicklin, Emily; Winter, Kevin
Contaminated surface water runoff from inadequate drainage and sanitation systems in informal settlements threaten the quality of available freshwater and can negatively impact both human and environmental health. Biofiltration systems (biofilters) provide water pollution controls without inputs of additional energy and chemicals, placing them in the overall context of the need for affordable and sustainable stormwater infrastructure in informal settlements. In addition, cleaned waters from biofilters may be suitable for some reuse applications if they are well-designed and maintained. However, most research is conducted in developed countries where heavy metals are the main surface water pollutant. Consequently, little is known about the extent to which biofilters can be used to meet the water quality targets in conditions likely to be found in informal settlements. In addition, no attempts have been made to recover or reuse the surface water runoff from informal settlements, despite its high nutrient loadings. This study analyses the extent to which biofilters can be used to clean and reuse contaminated surface water runoff from informal settlements. The objectives are threefold: (i) to analyse the performance of two field-scale biofiltration cells (one vegetated and one non-vegetated) that are batch-fed with surface water runoff from an upstream informal settlement; (ii) to determine the effects of varying operating, design and environmental parameters on the performance of the cells; and (iii) to develop a model which predicts the outflow pollutant concentrations under varying conditions. Both cells effectively reduced ammonia (NH3), Total Phosphate (TP) and Escherichia coli (E. coli) concentrations, but leached nitrate (NO3 - ) and nitrite (NO2 - ). The treated waters were suitable for irrigational reuse, however, additional disinfection was required to reduce faecal contamination in some cases. Correlation analyses showed that inflow water quality significantly influenced cell performance, with the vegetated cell outperforming the non-vegetated cell under higher inflow pollutant concentrations. Multiple regression models also investigated several parameters influencing outflow NH3 and showed that inflow pH, temperature and NH3 concentration can be used to determine the outflow NH3 concentration of the cells. These models are important for predicting cell performance and thus can be used to improve the design and/or operation of the cells for varying inflow water quality conditions.
Open Access
Analysing peak flow attenuation in an urban wetland
(2015) Giermek, Monica Grace; Winter, Kevin
Worldwide urbanization and climate change are influential in changing precipitation patterns and hydrological flow resulting in event driven urban flooding. The approach to flood protection has recently shifted from engineered and technical solutions to more sustainable and integrated solutions, by considering social, ecological and physical implications and exploring sustainable urban drainage options. Attenuation of peak stormwater flow using natural wetlands is one of many sustainable urban drainage methods used to reduce flooding and is an approach of interest for this research. The study site is located within the small, urbanized river system of the Liesbeek River in Cape Town, South Africa, which is prone to localized flooding during annual winter rainfall events. The study measures the attenuation capacity of a small-scale wetland adjacent to an urban river using a 2D PCSWMM hydrodynamic model. Research is focused on illustrating the attenuation capacity of this wetland. The model ran historic flow data to determine the attenuation capacity and to measure peak flow reduction. While the reduction is not sufficient to reduce damaging floods, the findings provide new knowledge and understanding of the attenuation capacity of this wetland and motivation for expanding sustainable urban drainage within the catchment. The study aims to build a baseline dataset for the research site with the data available at present. Peak flow of the Liesbeek River was reduced in scenarios with the Valkenberg Wetland present to accept on a portion of this flow. Attenuation was most effective for rainfall events with sudden spikes in peak flow, where a 42 per cent reduction of peak flow was observed. For a scenario with lower flow rates yet a prolonged peak flow rate, the wetland was less effective, with a 20 per cent reduction observed. This wetland was found to have the potential to provide valuable ecosystem services to the area by attenuating peak flow and thus reducing the occurrence of property damaging flooding downstream.
Open Access
Analysing stormwater temperature at site-specific discharge points along the Liesbeek River, South Africa
(2016) Crisp, Annesley; Winter, Kevin
Increased urban development has resulted in increased impervious landcover and the removal of natural vegetation. The continued anthropic modification of the Earth's surface towards an urban state, has had profound effects on the surrounding natural systems (Thompson et al., 2008). Consequently, recent studies have highlighted a strong link between expanding urbanisation and thermal impacts on streams and rivers draining urban catchments (Roa-Espinosa et al., 2003; Arrington, 2003; Herb et al., 2009b). Anthropogenic perturbations such as thermal pollution can adversely disturb the natural thermal regime of a river (Boothe and Bledsoe, 2009). An important source of thermal pollution is thermally enriched stormwater runoff. During a rainfall event, runoff temperature is elevated as it makes contact with, and passes over surfaces which have a large heat storage capacity, such as pavements, roofs and roads (Young et al., 2013). However, the extent of impervious surfaces and resulting thermal pollution produced by them is poorly understood, although it is thought to be a major contributor to stream degradation. Previous research has focused on investigating the thermal effects of removing riparian vegetation. Additionally, a recent research approach has been to develop models of the urban surface-water-atmosphere systems. Finally, research in the field of fresh-water ecology has investigated the effects of temperature on aquatic biota. Water temperature affects all aspects of freshwater ecosystems and plays an important role in regulating physical and biological characteristics of a river (Olsen et al. 2011). Consequently, any anthropogenic modification to temperature can have devastating effects on the ecological functioning of a river and biodiversity of species within the river habitat. Important findings by Young et al. (2013) suggest the need for a detailed study of stormwater temperature changes in relation to rainfall events, at a catchment scale. Furthermore, data is required to show the point source effects of stormwater runoff from impervious surfaces on the temperature of the receiving water body. Therefore, the aim of this study is: To determine the extent and risk of thermal pollution at site specific discharge points, along the Liesbeek River. In order to achieve this aim, variables which cause temperature variations needed to be identified. The primary research method makes use of Thermocron iButton Temperature Loggers. These were placed in four stormwater outlet pipes, which frequently discharge event-based stormwater runoff into the Liesbeek River. Additionally, iButton loggers were placed in the river channel, to provide a reference temperature to compare stormwater discharge temperature. In addition, hourly rainfall and air temperature was acquired from the South AfricanWeather Service (SAWS) and was used in conjunction with the iButton temperature data.
Open Access
An analysis of diatoms as biological indicators of water quality in rivers of the Western Cape
(2015) Slingers, Oliver; Winter, Kevin
In South Africa the systematic collection of water samples from surface waters and the collation of results is the responsibility of the Department of Water and Sanitation, previously the Department of Water Affairs and Forestry. Local authorities and private contractors are also responsible for conducting water quality tests for reporting purposes. In most cases, samples are collected by hand at predetermined sites and intervals across the country, and are tested for a standard set of parameters that covers various physical, chemical and bacteriological water quality measures. This approach and method of monitoring is time consuming, expensive and requires a high level of skills and capacity to achieve a representative and reliable sample. There is no immediate substitute, although there is a resurgence of interest in the use of bio-indicators in monitoring rivers. In this study, diatoms are investigated as an indicator of water quality because of the relative abundance of species and the ease with which they can be collected in the field, and the establishment of taxonomies of species that are aligned to pollution levels. There is limited knowledge about diatoms species found in lotic conditions, and in seasonal conditions in a Mediterranean climate where the surface water is slightly acidic. This study investigates the use diatoms in lotic waters of the Western Cape and compares this information to surface water quality measurements in the upper and middle course of the Berg River. The study commences by establishing baseline information of diatoms species for the upper to middle section of the Berg River which coincides with sites where surface water samples are regularly collected by the Department of Water and Sanitation. The study was conducted over a 12 month period in order to analysis the response of species to seasonal change and in relation to changing conditions at various point sources of where there is a known discharge into the Berg River. Species and population will be compared to the typological classification of diatom species and in relation to surface water quality. The study seeks to understand how diatoms respond to acidic waters of the Berg River; to measure the response of diatoms to changes in the water quality along the length of the river; and to determine the response of diatom species to point sources discharging water of varying quality into the river.
Open Access
An analysis of surface water from an informal settlement, Langrug, Franschhoek: down a slippery slope
(2018) Fell, Jessica; Winter, Kevin
Contaminated surface water from limited sanitation and drainage systems in informal settlements degrades receiving rivers. However, little is known about the water quality and flow of rivers draining informally settled catchments. This study explores the dynamics of a human water system in an informally settled catchment in the present, and then uses these insights to investigate possible trajectories in the future. The objectives are twofold: (i) to characterise the water quality and flow of a river draining an informally settled catchment in Franschhoek, South Africa, and, (ii) to investigate the hydrologic and water quality effects of future land use and climate changes in the catchment. River water samples were collected during dry days for four months and over five rainfall events. Highly elevated concentrations of NH₃-N (8.4 ± 5.2mg/L), PO₄³⁻ (5.9 ± 7.4mg/L) and TSS (135 ± 124mg/L) were recorded in the informal settlement. Correlation analyses between land use types and water quality showed significant relationships between informal settlement and NH₃-N, PO₄³⁻, DO, EC and TSS. Multiple regression models investigated six hypothetical land use changes scenarios and indicated that if informal settlement and built-up area doubled in size, there would be an increase in the concentration of NH₃-N by 83%, PO₄³⁻ by 85% and TSS by 86%. During the rainfall events multiple NH₃-N, PO₄³⁻, TSS concentration peaks were observed, with concentrations peaking at 3.5mg/L, 6.6mg/L and 1868mg/L respectively. Various significant correlations between lagged rainfall and pollutant concentrations revealed that rainfall caused an increase in NH₃-N, PO₄³⁻ and TSS after one hour, while NO₃⁻-N and DO responded to rainfall after two hours and flow after three hours. Multiple regression models explored two hypothetical climate change scenarios involving an increase in the 10 and 20 year design rainfall depth. The models demonstrated that if the rainfall depth of a 20 year rainfall event increased by 15%, there would be an increase in peak concentration of NH₃-N by 17% and PO₄³⁻ by 15%, a decrease in DO by 21%, and an increase in peak flow by 21%. The results reveal the pervasive impacts of the informal settlement on river water quality, especially as regards nutrient contamination from wastewater. The land use and climate change scenarios serve as a warning of the long term consequences of inevitable land use and climate changes in informal settlements.
Open Access
An analysis of the ability of small urban wetlands to treat stormwater: the case of Princess Vlei wetland, Cape Town
(2018) Underhill, Laura; Winter, Kevin
The consequences of poor water quality on urban aquatic ecosystems have been well established by researchers worldwide. Stormwater management in the urban areas of South Africa predominately focuses on the collection and diversion of runoff into the nearest receiving water body, with little acknowledgement of the impacts on the environment. The City of Cape Town Metropolitan municipality is an authoritative entity on Cape Town pollution and has acknowledged that polluted stormwater is a significant contributor to the deterioration of its' urban aquatic ecosystems due to the persistence of conventional drainage systems. Small urban wetlands are often overwhelmed by the quality of stormwater and urban runoff. Thus water bodies receiving urban stormwater runoff often have elevated loadings of pollutants. In theory wetlands are capable of treating these pollutants and improving water quality through various ecosystem services, but understanding the performance of wetlands under varying conditions is difficult to determine. In South Africa, there is a paucity of studies focussing on the impacts of urban development on small, urban wetlands and thus their ability to provide ecosystem services. This study aimed to identify the surface water quality of Princess Vlei, a small urban wetland, over the past 8 years, and establish the ingress and outflow of the wetland. The pollutant concentrations within the wetland were best explained by the predictor variables of total rainfall and progression of time. Impacts of total rainfall differed with various parameters resulting in larger volumes of water entering the wetland either diluting pollutant concentrations or elevating pollutant concentrations. These inverse trends were proved through the significant correlations found between total rainfall and COD and total rainfall and EC, while the variable of time influenced the wetland's ability to provide ecosystem services, either through the accumulation, retention or flushing of pollutants. The accumulation of pollutants over time was identified through the increasing concentrations off COD and PO₄³⁻, with the exception of NH₃-N that decreased over time. This implies that the wetland was able to assimilate the NH₃-N but not the COD and PO₄³⁻. The results did not suggest that the wetland was able to treat the water, as the literature emphasises, rather, confirmed the pervasive impacts of the urban catchment on the ability of ecosystem services to treat water quality in the wetland.
Open Access
An analysis of the performance of constructed wetlands in the treatment of domestic wastewater in the Western Cape, South Africa
(2013) Lakay, Vanessa Monique; Winter, Kevin
Constructed wetlands (CWs) are being introduced in many parts of the world to treat wastewater. CWs offer several advantages over conventional treatment, most notably to save costs and energy. By contrast there are several limitations associated with the use of CWs, such as variability and unpredictability in treatment performance. However the literature focuses largely on the advantages of the CWs with little attention being given to the limitations and impacts on the receiving environment. In South Africa, there are a few studies concerned with the application and performance of CWs, but as yet there are no guidelines for the design and construction of these systems. The aim of this research is to determine the performance of three CWs situated on the periphery of Cape Town, Western Cape, with the intention of contributing to knowledge on the South African CWs performance in general. The research interest was to purposely shift attention to an analysis of the performance of CW systems that could be measured in-situ as opposed to laboratory-based studies where certain variables could be contained or controlled. In this study the focus is on determining the impact that these systems might have on the surrounding environment by analysing the impact from these CWs on surrounding or receiving water bodies. Samples of influent and effluent were collected from various points within the CW and from the surrounding water bodies every two weeks during the winter season when biological activity is least productive. Performance was determined by considering the mean percentage change from influent to effluent, the significance of the difference between influent and effluent and by comparing resultant effluent quality to the Department of Water Affairs' discharge standards. The results of the study indicate a range of performance both within and between systems, but overall the performance was poor, with the exception of NH3 (96%) and E. coli (see below) that was removed at one of the sites, namely, at De Goede Hoop. While PO43- was adsorbed, it was very low at all three sites; 3.8%, 7% and 20% at De Goede Hoop, Wolwedans and Babylonstoren respectively. Furthermore, DWA's effluent standards of 10 mg/l for PO4 3- could not be met at all the sites. Poor PO4 3- removal can be explained either by low O2 concentrations or the choice of substrate that was used in the constuction. When O2 concentrations are low, solubilisation of minerals and subsequent release of dissolved of phosphorus occurs. Mean E. coli removal percentages were considerably lower compared to other studies undertaken elsewhere. E. coli removal was 85% at De Goede Hoop, 39% at Wolwedans and 65% at Babylonstoren. In general, the results indicate that more research on CW systems is required to improve our understanding of these systems. A better understanding of these systems will lead to enhanced design and thus assist in improved treatment performance so as to reduce the impact of CWs on the environment.
Open Access
An analysis of the spatial and temporal changes in the Riparian zone of the Berg River in the vicinity of Hermon: implications for governance
(2013) Nyemba, Anesu Angelic; Winter, Kevin
Riparian zones broadly refer to the interface between terrestrial and aquatic systems. It is widely acknowledged that riparian zones provide a number of services including that of an ecological corridor for migration of animal species; a habitat; food for aquatic macro invertebrates in the form of organic matter; stabilising river banks; filtering nutrients and sediments from water that discharges off surface slopes and land; and protecting and improving water quality of river systems. This study examines how the Berg River riparian zone has changed over the past few decades and then considers the implications for governance of these zones in South Africa. The study identifies changes in vegetation composition and spatial extent of the riparian zone. The study site is a stretch of the Berg River in the Hermon area. Changes in vegetation and the spatial extent of the riparian zone over time were identified and mapped using aerial photographs of the study area spanning a period from 1955 to 2012. The results of the study showed that the spatial extent of the riparian zone decreased by 29.3% from 55 ha in 1955 to 39 ha in 2012. At the same time the area covered by trees (Eucalyptus globules) increased from 3.84 ha in 1955 to 35.94 ha while the area covered by shrubs that could be detected from the sources, decreased from 46.10 ha in 1955 to close to zero in 2012. The results of this study reveal a lack of governance in the river system. The lack of governance is attributed to the fact that the Berg River Catchment Management Agency is not operational. In South Africa weak governance in the management and responsible care in safeguarding riparian zones has compromised water quality, ecological integrity and habitat of the river system.
Open Access
An analysis of water quality discharging into the Berg River at Paarl, Western Cape
(2010) Mgese, Sivile; Winter, Kevin
In densely settled urban and peri-urban areas of South Africa, stormwater infrastructure is frequently being used as a conduit for the daily discharge of effluents resulting in the deterioration of rivers and other receiving water bodies. This study investigates the pollution load from urban localities entering the Berg River at Paarl, and in particular, seeks to determine whether or not there is a difference in the pollution load immediately after periods of wet and dry weather conditions.
Open Access
Applying water footprint assessment with the aim of achieving sustainable water resource management at a large commercial beef cattle feedlot in Gauteng Province
(2016) Pearce, Lisa; Winter, Kevin
The commercial production of beef meat is associated with a wide array of environmental impacts, and is itself very sensitive to environmental conditions. Water in particular is a critical environmental resource and the commercial success of an agri-business is closely tied to reliance on fresh water resources. In an economic sector that is increasingly faced with competition for resources as well as negative public opinion about environmental impacts, the management of water-related risks and impacts is essential to ensure business resilience and sustainability. Global trends in animal production are causing the environmental problems to become more harmful, and intensive animal production is being separated from traditional crop farming systems where manure could be used as a fertilizer to replenish soil nutrients. There is a spatial disconnect in the production value chain brought about by commercial trends. An on-site water efficiency approach to water resources management of an agri-business does not enable it to evaluate value chain water-related risks, or its' own contribution to sustainable water use in the catchments where raw materials are produced and production wastes are distributed. The question of sustainable water use within the production value chain of beef meat is not solved with an on-site efficiency approach to water resources management because the approach is inadequate in evaluating the freshwater environmental impact, or in managing water-related business risks of the whole beef production value chain. It is argued that a systems approach is more credible because it allows a beef cattle feedlot enterprise to evaluate freshwater impacts across the production value chain and will enable a feedlot to transition towards a sustainable value chain water resources management model The Water Footprint of food, goods and services is a volumetric expression of the water that is consumed during the production process. Unlike water use, the water footprint refers to water that is imbedded into a product (also referred to as virtual water) or otherwise made unavailable for further use within a catchment, province or country through pollution dilution. The Water Footprint Network developed the Water Footprint Assessment and describes three types of WF: the green water footprint refers to evaporated water, typically in the form of rainwater. The blue water footprint refers to water that is abstracted from a resource and delivered to the point of use, for example in the case of irrigation from a river, borehole or dam. The grey water footprint is a volumetric expression of the amount of fresh water required to dilute chemical substances to a safe or acceptable concentration in the natural environment. A Water Footprint Assessment (WFA) was undertaken at a beef cattle feedlot in Gauteng, South Africa. The WFA focused on the Bovine WF of the 4-month winter- and summer finishing periods that cattle spend at the feedlot. The second focus was on the monthly grey WF of waste management activities at the feedlot. The purpose of the study was to determine how the application of a WFA would enable an agri-business to transition from an on-site approach to water resources management, to a value-chain systems approach to sustainable water resource management.
Open Access
The capacity of the Cape Flats aquifer and its role in water sensitive urban design in Cape Town
(2017) Mauck, Benjamin Alan; Winter, Kevin; Wolski, Piotr
There is growing concern that South Africa's urban centres are becoming increasingly vulnerable to water scarcity due to stressed surface water resources, rapid urbanisation, climate change and increasing demand for water. Furthermore, South Africa is a water-stressed country with much of its surface water resources already allocated to meet current demands. Therefore, in order to meet the future urban water supply requirements, countries like South Africa will need to consider alternative forms of water management that focus on moving towards sustainability in urban water management. WSUD is one such approach that aims to prioritise the value of all urban water resources through reuse and conservation strategies, and the diversification of supply sources. This study investigates the capacity of the Cape Flats Aquifer (CFA), assessing the feasibility of implementing Managed Aquifer Recharge (MAR) as a strategy for flood prevention and supplementing urban water supply. The implementation of MAR on the CFA aims to facilitate the transition towards sustainable urban water management through the application Water Sensitive Urban Design (WSUD) principles. The fully-integrated MIKE SHE model was used to simulated the hydrological and hydrogeological processes of the CFA in Cape Town at a regional-scale. Using the results of the regional-scale model, four sites were selected for more detailed scenario modelling at a local-scale. Several MAR scenarios were simulated to evaluate the aquifer's response to artificial recharge and abstraction under MAR conditions. The first objective was to evaluate the feasibility of summer abstractions as a flood mitigation strategy at two sites on the Cape Flats prone to winter groundwater flooding, viz. Sweet Home and Graveyard Pond informal settlements. The second objective of the study was to assess the storage potential and feasibility of MAR at two sites in the south of the Cape Flats, at Philippi and Mitchells Plain. In addition, the migration of solute pollutants from the injected or infiltrated stormwater was simulated and climate change simulations were also undertaken to account for potential fluctuations in rainfall and temperature under climate change conditions. The results indicated that flood mitigation on the Cape Flats was possible and was likely to be most feasible at the Graveyard Pond site. The flood mitigation scenarios did indicate a potential risk to local groundwater dependent ecosystems, particularly at the Sweet Home site. Yet, it was shown that a reduction in local groundwater levels may have ecological benefits as many of the naturally occurring wetlands on the Cape Flats are seasonal, where distinct saturated and unsaturated conditions are required. Furthermore, MAR was shown to improve the yield of wellfields at Philippi and Mitchells Plain through the artificial recharge of stormwater while also reducing the risk of seawater intrusion. MAR was shown to provide a valuable means of increasing groundwater storage, improving the supply potential of the CFA for water supply while aiding the prevention or mitigation of the seasonal flooding that occurs on the Cape Flats. Furthermore, the case was made that MAR is an important strategy to assist the City of Cape Town in achieving its WSUD objectives. MAR and groundwater considerations, in general, are essential for the successful implementation of WSUD, without which, there is an increased risk of overlooking or degrading urban groundwater resources. The findings of this study resulted in a number of recommendation to urban water resources managers, planners and policy makers. First, MAR is an important means for Cape Town to move towards becoming a truly water sensitive city. This study indicated that the CFA should be incorporated as an additional source of water supply for Cape Town especially considering the recent drought conditions and due to its ability for the seasonal storage of water, this would improve the city's resilience to climate change. Furthermore, it was recommended that the application of MAR on the CFA could also be used to reduce groundwater related flooding on the Cape Flats. Second, it was emphasised that urban planning, using WSUD principles is essential for the protection of the resource potential of the CFA. Finally, for the implementation of WSUD and MAR to be successful, there needs to be appropriate policy development alongside the implementation of these strategies to ensure they are achieving their initial objectives and are not causing detriment to the aquifer.
Open Access
The concept of shared risk in public and private sector water security: a case study of Grabouw and the Elgin Valley, Western Cape, South Africa
(2015) Baleta, Hannah Francis; Winter, Kevin; Pegram, Guy
This thesis investigates water risk in small-to medium-sized agro-processing companies and the public sector. Global interest in water management from the private sector has led to an increase in the development of water risk tools that are available to companies. Not only has the number of tools increased, but also the quality and form of these tools has been refined. Water risks are complex and extensive, and cannot be managed alone. Private sector interest in partnership and collaboration with other actors in managing water risk has increased as a result. The principal aim of this thesis is to investigate and explain the idea of shared water risk, using an adaptive theory process within a case study to investigate the understanding and knowledge of water risks among public and private actors. The study is informed by an assumption that if private and public interests are aware of the collective risks within a catchment, then sustainability of those business enterprises and public services, along with the protection and conservation of water resources may be possible. The case study is located in Grabouw and the Elgin Valley in the Theewaterskloof Local Municipality, Western Cape, South Africa. Private sector actors include agro-processing industries in the region, while the public sector includes local municipality officials and water resources management institutions such as the Catchment Management Agency and the Water Users Association. A conceptual framework of water risk and a sharing typology was developed from an analysis of interviews and the use of secondary sources of documents on the hydrology and socio-economic information on the catchment. The conceptual framework identifies the different water risks of the private and public sector, while the sharing typology indicates the progression of knowledge and understanding of private and public sector water risks, recognising that sharing does not take place in a single form. The framework and the typology together are intended to integrate an understanding of the theory and empirical data. Refinement of the framework and typology found that shared risk is especially pertinent in situations where systemic water risks affect the management of water and where that risk cannot be managed by individual companies or public sector authorities alone. The conceptual framework and typology identify the private and public sector exposure to risks, enabling actors to understand the scale and form of the respective risks in each sector. Where risks are not shared, the process of investigating the knowledge and understanding of risks helps to identify the complexity of the system. Contributions of this thesis include the use of risk as a common language to help bring together diverse sectors, especially when participatory decision-making is required. Not only the technical aspects of water supply and sanitation, but the wider social and environmental factors need to be considered as well. Understanding water security as a risk enables a wider and more diverse stakeholder group. The thesis concludes that collaboration and adaptive management need to be informed by knowledge and understanding of the complexity of risks within the catchment by multiple stakeholders.
Open Access
Determining youths' level of understanding of environmental concepts in the sail training environment
(2010) Kilian, Kay-Leigh; Winter, Kevin
The aim of this study is to determine youths' level of understanding of selected environmental concepts measured by their verbal responses. With the hypothesis being that youth would be able to observe their environment and note differences and similarities, with a basic understanding of concepts, especially those in the school curriculum but unable to take this further by hypothesising on why differences occur which is more typical of youth of ages 15 years and above. Youth would especially struggle to hypothesise theoretical and abstract concepts as opposed to describing what they observe. It is expected that studies by Piaget will be informative with regards to the cognitive developmental stages in the youth as being categorised into either stages three ( concrete-operational) or four (formal-operational). The study involved nine youths from Christel House, Cape Town, who were selected and assessed on their understanding of four environmental concepts. The crew of the sail ship noted their responses during various lessons offered on board before proceeding with the next. The results indicated that the participating youth were able to compare two different observed scenarios as being either similar or different, but were unable to compare theoretical scenarios. Once differences or similarities were established, youth were unable to link factors to hypothesise about why these differences or similarities were occurring, even when prompted or given clues from a crewmember on board the ship. However, the participants were able to hypothesise about the effects of one variable on another when they could actively manipulate a concept to see what might happen under given conditions.
Open Access
An ecotourism approach to tourism development in the Green Kalahari District of the Northern Cape Province
(1999) Owen, David; Winter, Kevin
This dissertation arises from a study commissioned by the Peace Parks Foundation to investigate the feasibility of establishing a new conservation area known as the Gariep Transfrontier Conservation Area (GTFCA), entitled; Feasibility Study of the Proposed Gariep Transfrontier Conservation Area: Environmental Overview of the South African Section. The proposed GTFCA encompasses an area of 2,774 km2 (277,400 hectares) straddling either side of the Orange River, which represents the international border between South Africa and Namibia. The author of this dissertation was a member of a small team of postgraduate students from the Department of Environmental and Geographical Science at the University of Cape Town who spent six months, from November 1997 to May 1998, focusing on the South African section of the proposed GTFCA, which covers approximately 2,000km2 and is situated in the Northern Cape (MAP 1).
Open Access
The effects of greywater irrigation on vegetable crops and soil
(2013) Mzini, Loyiso Lloyd; Winter, Kevin
Research on greywater irrigation has mainly focused attention on the reuse of greywater in relation to its quality and crop biomass but not on quality of edible vegetable crops. Thus a field experiment was established at the Umtata Dam Research Station where combinations of cabbages and onions; spinaches and beetroots; and carrots and lettuce were planted in to coincide with four different planting seasons (from October 2009 to December 2010). Crops were irrigated with greywater generated from bathing and dishwashing. Greywater was collected from a number of households in the vicinity of the Umtata Dam, in the Eastern Cape Province of South Africa. In the field experiment, vegetables were planted in three plots of the same composition of soil properties and then drip irrigated separately either with greywater, potable water, or with diluted greywater at a ratio of 1:1. The greywater quality, yield, aesthetical appeal, plant chemical analysis and soil chemical analysis were measured. Irrigation from diluted greywater showed a significant increase in yield, in the head mass and in appeal of cabbages. Onion yields were significantly higher when irrigated with greywater. Spinach also obtained significantly higher yields when irrigated with greywater, however many leaves from this treatment were infested with leaf-spot disease. Beetroot yield and quality was not affected with greywater irrigation, instead yield was reduced by 47% (4.686 tons/ha). Carrots did not show any significant difference in yield and root girth, but carrots irrigated with potable water were more appealing and longer in length. Lettuce irrigated with dilute greywater was significantly more appealing than other treatments. Sodium (Na) ions were elevated in cabbage, onions and were significantly higher in the case of lettuce and carrots when irrigated with greywater. Crude protein (CP) was observed to be significantly elevated on cabbages and lettuce when irrigated with diluted greywater whereas CP of onions and carrots were significantly lower due greywater irrigation. Significant increases in iron (Fe) were observed on cabbages and spinach when irrigated with diluted greywater, whereas lettuce Fe content was significantly elevated by greywater irrigation. There was no significant difference in cadmium (Cd) caused by irrigating spinach and lettuce with greywater, also those heavy metals that were significantly higher, were within the accepted threshold leaving the conclusion that lower levels of heavy metals posed no health risks to humans. In conclusion, greywater used in this study does not appear to cause an accumulation of salts and heavy metals in plants and soil, which suggests in this instance, that greywater does not pose a threat to plants and soils.
Open Access
Environmental perceptions : a case study of Fish Hoek Senior High School
(1997) Mann, Peter J; Winter, Kevin
The study was initiated as a result of a growing concern of the researcher at the apathy prevalent amongst his students at Fish Hoek Senior High School towards environmental activities which took place out of'school hours. Linked to this was a perceived lack of understanding of environmental issues and very little commitment towards positive environmental actions such as recycling. These were students in the final phase of their secondary education at a school situated in a valley bounded by mountains and two oceans and serving a community which is continually involved in disputes over environmental issues. It was therefore disturbing that the environmental experiences both inside and outside the school had largely failed to produce environmentally-committed students. The purpose of the study was to gauge student perceptions and feelings concerning a wide range of environmental concepts and issues both globally and locally. In addition, it was an attempt to establish the level of personal commitment of the students towards a variety of positive environmental actions.
Open Access
Estimating farm dam storage using SPOT imagery
(2011) Petersen, Nicole Jade; Winter, Kevin
The objective of this study is to establish a methodology in which remote sensing can be used to support the monitoring of water resources. SPOT XS imagery and object-oriented classification was used to identify farm dams and their surface area. Two equations applied to determining the capacity of dams were used to convert surface area to volume. The results showed a similarity between fieldwork and object-oriented classification data for surface area. Overall, there appears to be a strong positive correlation between object-oriented classification and unsupervised classification. The correlation between object-oriented classification and supervised classification ranged from strong positive association to little or no association. This study concludes that remote sensing is a useful tool in identifying water bodies and generating an estimate of volume stored.