Browsing by Author "Carden, Kirsty"

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    Open Access
    A System Modelling Approach to Assessment of Hybrid Water Supply Solutions in eThekwini Municipality
    (2021) McKune, Danica; Carden, Kirsty
    Water security in South Africa is a major concern, particularly in the context of urbanisation, the concomitant increases in water demand, and the potential for climate change to aggravate water shortages. Provision of basic services remains a significant challenge. Improving economic and social equity, vitally supported by adequate water supply and water quality, while ensuring environmental sustainability (maintaining water resources requires healthy ecosystems) is the dual challenge facing South Africa. There is growing recognition of the need for alternative approaches to water management, such as Sustainable Urban Water Management (SUWM). Decentralisation and integration to allow consideration of the total water cycle are fundamental themes of the SUWM paradigm. There is theoretical and experiential evidence that the current infrastructure archetype (of conveying a particular water stream from origin to destination by the most efficient means) could benefit from inclusion of such principles. SUWM is purported to have three core benefits: (1) A more natural water cycle, (2) Improved water security through diversification of sources, and (3) Resource efficiency. A complete transition to alternative water provision models is neither economical nor practically feasible in already developed areas, necessitating innovations in new areas and as retrofits to existing systems; systems where the water services configuration is evolving in this way are termed hybrid systems. Alternative water provision models bring dynamic changes to existing systems which may not be intuitive: the complexity of urban water systems and the resulting uncertainty means an intervention may achieve one SUWM objective yet undermine another. Thorough evaluations of alternative water provision models are therefore essential, while recognising that less learned experience on the performance of innovative solutions means uncertainty remains part of the evaluation. This research therefore aims to contribute to the theoretical body of knowledge on the net system effects of integrated management of the water cycle where alternative and decentralised solutions are introduced to existing systems. The overarching research objective was therefore application of an assessment framework, which was underpinned by the development of a systems dynamics model in GoldSim software. The systems dynamics model has been tailored for application to the selected case study area – eThekwini Municipality in South Africa. Akin to most South African cities, this region is home to a diverse range of consumers (fully serviced urban suburbs, informal settlements, peri-urban settlements, and rural areas), is experiencing urbanisation and growth in demand, and is supplied by catchments whose water resources are fully developed and are at risk of becoming significantly stressed. This is set against a backdrop of challenges in service delivery, environmental concerns as a result of water practices, potential impacts of climate change in the future, and ultimately sustainability of service provision. The developed systems dynamics model is a macro-scale integrated flow model, capable of assessing implementation of water servicing scenarios (specifically any combination of Water Conservation and Water Demand Management, rainwater harvesting, stormwater harvesting, groundwater use, greywater reuse, wastewater recycling, and desalination) at a regional level. Monte Carlo analyses were carried out to test system sensitivity to uncertainty in particular parameters. Of the possible interventions, five scenario paths were assessed: (1) Baseline, or “business as usual”, (2) WCWDM, (3) rainwater harvesting and real loss reduction, (4) greywater reuse and WCWDM, and (5) wastewater recycling and real loss reduction. Considered against the three core benefits of SUWM, each of the intervention scenarios yielded positive results. The developed model proved valuable in the scoping of SUWM interventions, and understanding the system-wide effects SUWM interventions may have on the water cycle. Such systems modelling approaches may therefore be considered to provide the framework and parameters within which further detailed and project-specific hydraulic and contaminant transport analysis could take place.
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    Open Access
    Evaluating water conservation and water demand management in an industrialised city: a case study of the City of uMhlathuze in Richards Bay
    (2018) Mthethwa, Nkosinathi I; Carden, Kirsty
    The objective of this study was to evaluate water conservation and water demand management in an industrialised City of uMhlathuze in Richards Bay. The City of uMhlathuze Local Municipality is the third-largest municipality in KwaZulu Natal (KZN) and is strategically placed to continue attracting investment as an aspirant metropolis due to the newly established Industrial Development Zone (IDZ) and the country's largest deep-water port. As an industrialised city, uMhlathuze's demand for water is already increasing and with the establishment of the IDZ, it is expected that water demand will escalate even further once the IDZ is fully operational. In line with the research question, this study has, therefore, sought to understand whether the industrialised City of uMhlathuze has developed and effectively implemented a water conservation and water demand management strategy and interventions in order to sustain water supply in anticipation of growing demand due to industrialisation and population growth. This objective was achieved by evaluating the city's current interventions and measures using a range of water conservation and water demand management solutions and guidelines. During this study, it was evident that the greatest threat facing South Africa's ambitious future economic growth, poverty alleviation and government's transformation agenda was the inefficient and unbalanced use of available and limited water resources. Thus, in order to avoid this imminent threat, the country as a whole must continuously reduce water consumption and demand from various sectors. This goal can be achieved through sustainable and improved water conservation and water demand management interventions. The study found that, in recent years, the issue of water scarcity had escalated in KZN. The province was in the grip of a drought, which was taking its toll on water supply in various municipalities around the province. The sparse rainfall in most parts of the province had caused the levels of rivers and dams to decrease to a point of crisis. Consequently, the KZN Provincial Government declared the province a disaster area in 2015. During the study, there was very little improvement as the City of uMhlathuze was still subjected to level 4 water restrictions. Evidently, the drought was intensifying the water problem in a municipality already grappling with poor and inadequate water infrastructure. A review of international and local literature was undertaken to theoretically position the objective of the research. An evaluation of the City of uMhlathuze water conservation and water demand management strategy and interventions was conducted using a questionnaire completed by city officials and part of the study included documentation review. This study investigated key elements of water conservation and demand management as well as interventions that were pertinent to achieving the desired outcome of efficient use of water. Respondents were required to answer questions focusing on several water conservation and water demand management related approaches and solutions. During the study, it was identified that there were inconsistencies in the implementation of water conservation and water demand management interventions even though the City of uMhlathuze had already taken the important step of developing a water conservation and water demand management strategy. It was recognised, however, that water conservation and water demand management remained relatively new for most municipalities. Consequently, it would take time for municipalities, together with communities, to implement effective interventions. The focus needs to be on the establishment of a combined team of staff and stakeholders, set up to finding solutions and interventions designed to maximise the most sustainable and efficient use of water. The conclusions drawn from this study and proposed recommendations indicated that wastewater reuse; pipe replacement; water pressure management; rainwater and stormwater harvesting; water sensitive urban design; leak detection and repair; joint planning and research team with the Industrial Development Zone; groundwater and aquifer recharge; stakeholder engagement, education and citizen awareness are feasible options for the City of uMhlathuze to consider in relation to water conservation and water demand management. These solutions should constitute the foundation of a revised and updated water conservation and water demand management strategy to be implemented incrementally with broad-based participation.
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    Open Access
    A measure of sustainability in the context of urban water management in South Africa
    (2013) Carden, Kirsty; Armitage, Neil
    The aim of this research was to develop an understanding of and measure the potential for sustainability in a South African urban water context. This was achieved through the use of a systems approach to develop and evaluate a composite index – the Sustainability Index for Integrated Urban Water Management (SIUWM) – based on a vision of what sustainable urban water management means to decision makers at selected local authorities around the country. The vision was expanded into a sustainability framework to identify suitable key indicators for the index, as well as those which link with existing regulatory measurement initiatives in the South African water sector. The hypothesis was that if a city improves its scores on all of its indicators over a period of time, there is potential for long-term sustainability in the specific urban water system. The SIUWM was applied as a ‘snapshot’ analysis to nine case study cities (using 2010 / 2011 figures) and the results highlighted the inherent strengths and weaknesses in the management of urban water in each city, and consequently across each dimension of sustainability. Regularly-updated and publicly-available quantitative data as well as qualitative information from interviews with municipal officials were used as input to the index. Key performance indicator scores from the Department of Water Affairs’ regulatory performance measurement systems were also used in the computation of the index scores. In this way the SIUWM was able to provide a detailed analysis which could be used over time to track changes in performance, establish goals and inform strategic processes to leverage support for improved water services. Through its visioning process, the SIUWM is also able to identify vulnerabilities in the water system and provide information that is potentially useful for mitigating the root causes of these vulnerabilities. Sustainability assessment in the urban water sector, by way of initiatives such as the SIUWM, is not only about taking stock of progress – it is also about identifying shortcomings and challenges so as to contribute to initiatives and policy-making aimed at achieving sustainability. By clarifying what sustainability constitutes in the context of urban water management in South Africa through the use of a multi-dimensional approach to sustainability assessment (as is achieved by way of the SIUWM), the mindsets of decision-makers can hopefully be successfully shifted to embracing a more integrated approach towards sustainable urban development and water sensitive cities.
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    Open Access
    Understanding the use and disposal of greywater in the non-sewered areas of South Africa
    (2006) Carden, Kirsty; Armitage, Neil
    There is currently a strong drive from the South African government to attain adequate water and sanitation coverage throughout the country as a basic level of service. To meet this requirement the majority of authorities in urban and rural areas are implementing on-site dry latrines (VIPs or similar) and 25 litres of potable water per capita per day (lied) within a 200m eartage distance. The connection of low-income settlements to municipal water sources has subsequently occurred on a massive scale, frequently without giving adequate attention to greywater management in those areas that are non-sewered. Recent estimates show that there are approximately 20 million people in South Africa (SA) without access to on-site waterborne sanitation (Statistics South Africa, 2005). In the absence of suitable conveyance systems, greywater is generally disposed of onto the ground outside the dwellings and the resulting total pollution load, particularly from densely populated settlements, has the potential to create a host of environmental and health impacts. It is likely that the problems related to the disposal and management of greywater will increase as basic water and sanitation services are attained and improved, and solutions are therefore required to circumvent this. This thesis describes the results of a two-year investigation into the use and disposal of greywater in the non-sewered areas of SA. The main aim of the research was to quantify the greywater problem and develop options for the management thereof, both in terms of reducing health and environmental risks by eliminating inappropriate disposal of greywater, as well as possibly providing benefits to some communities through controlled use. Greywater is deï¬ ned as the wastewater that is produced from household processes (e.g. washing dishes, laundry and bathing) without input from toilets. Non-sewered areas are deï¬ ned as those areas without on-site waterborne sanitation. On-site surveys of selected communities in six of the nine provinces of SA (39 sites in total) were conducted through the use of standardised questionnaires to assess current greywater management and recycling activities. The total volume of greywater currently being generated in the non-sewered areas of South Africa has been estimated by applying an average factor of 75% to the amount of water consumed per household and multiplying this with the number of non-sewered households in each province (using modiï¬ ed Census 2001 ï¬ gures). It is estimated that a total volume of just over 490,0O0m3 per day of grey-water is generated in non-sewered areas on a daily basis in SA. This amounts to approximately 180 million m3 per year - equivalent in volume to a medium sized dam such as Voelvlei near Cape Town, or approximately 50% of the current annual water demand of this city. This illustrates the relatively limited potential for the use of greywater from non-sewered areas as an alternative water resource at a country-wide scale, and suggests that the main beneï¬ ts from greywater use in these areas will be from irrigation at household level to supplement nutrition requirements. On the other hand, these ï¬ gures highlight the fact that greywater disposal in non-sewered areas is likely to result in signiï¬ cant health and environmental impacts, particularly in dense urban environments where large volumes of greywater are generated in relatively small areas. Limited water quality sampling of typical greywater and source water was undertaken during the surveys to try and get a general understanding of the overall quality of the greywater emanating from non-sewered areas, particularly in respect of its nutrient loading and oxygen demand. The results suggested that greywater is generally unï¬ t for use except under controlled conditions. In particular, not enough is known at present about the health challenges that may be faced by the use of greywater for the irrigation of food crops, and the management of any recycling practice is therefore crucial. Unrestricted use of greywater without education on the risks involved and supervision of the practice to ensure adherence to safety precautions is likely to increase the disease burden on those who can least afford it. The determination of typical volumes of greywater generated per hectare for non-sewered settlements and the likely impact of changes in service levels with respect to water supply have been calculated by using average water consumption data determined from on-site surveys and updated settlement data from Census 2001. A model has been developed in which greywater management options for non-sewered areas are determined by way of a series of rule-based flow diagrams which raise relevant questions for each of the criteria in order to assess various alternatives for greywater management and disposal. Two main outputs have therefore resulted from the research; one at a strategic level and the other at an implementation level. Recommendations have been made to assist government policy makers in the development of strategies for the management of greywater, and greywater management options have been identiï¬ ed so that communities and municipal planners can implement the solutions required to reduce any negative impacts.
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    Using a diagnostic indicator assessment to understand sustainability transitions towards Water Sensitive Urban Design in the City of Cape Town
    (2018) Madonsela, Boipelo; Carden, Kirsty
    Cities globally are progressively becoming hotspots for water related risk and disaster mainly as a result of the cumulative effects of rapid urbanisation, population growth and the impacts of climate change. South African cities in particular are faced with the dual challenges of meeting demand for scarce water resources, as well as mitigating urban flooding. A shift towards adaptive and sustainable approaches has been proposed in order to address these complexities whilst ensuring the satisfactory delivery of water services to citizens. To support this change, local authorities are tasked with restructuring policy to include climate change adaptation strategies in order to adapt more adequately and proactively. In this regard, Water Sensitive Urban Design (WSUD) has gained importance in terms of guiding cities around the world in transitioning towards becoming water sensitive. WSUD aims to ensure that urban planning and design is undertaken in an interdisciplinary way and minimises the hydrological impacts of development on the surrounding environment. Sustainability transitions literature recognises that infrastructure and technologies are highly intertwined with institutional structures, regulations and social practices. For this reason, transitions towards sustainability-oriented technologies typically involve significant changes along assorted dimensions of the socio-technical system. Accordingly, this project aims to understand and identify the fundamental institutional conditions necessary to support a transition towards WSUD, using the City of Cape Town (CoCT) as a case study site. In order to achieve this aim, the City Blueprint Approach (CBA) was applied to the CoCT based on in-depth interviews and publicly available data. The CBA was developed by the KWR Watercycle Research Institute in cooperation with Utrecht University, The Netherlands and has been tested on various cities globally. It is a set of diagnostic indicator tools comprising the Trends and Pressures Framework, the City Blueprint Framework and the Governance Capacity Framework. The CBA assessment was followed by a thematic analysis to understand the context of transitions to a WSUD approach in Cape Town. The results of the research indicate that the CoCT has had some success in its efforts related to the sustainable management of water resources through the implementation of policy, action plans and a range of learning opportunities for city officials and local stakeholders. Despite these efforts however, issues of financial viability, implementing capacity and political will have hindered progression towards WSUD in the City. In conclusion, the research has emphasised that sustainable water management and a transition towards a WSUD approach requires more than just redesigned infrastructure; it has also highlighted the different institutional aspects that make transitioning towards WSUD possible both in Cape Town, as well as for other cities in developing countries with similar socio-economic contexts to South Africa.
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    Water, Sanitation, and Hygiene Vulnerability among Rural Areas and Small Towns in South Africa: Exploring the Role of Climate Change, Marginalization, and Inequality
    (2021-10-09) Abrams, Amber L; Carden, Kirsty; Teta, Charles; Wågsæther, Katinka
    Access to water, sanitation, and hygiene (WASH)—including drainage-services—is essential for public health and socio-economic development, but access remains inadequate and inequitable in low- to middle-income countries such as South Africa. In South Africa, rural areas and small towns generally depend on a limited and climate-sensitive economic base (e.g., farming), and they have a limited capacity and are located in areas where transport challenges can increase WASH access risks. Climate change shifts hydrological cycles, which can worsen WASH access and increase susceptibility to the interlinked impacts of droughts and flooding in already vulnerable regions. We adopted a transdisciplinary approach to explore the needs, barriers, and vulnerabilities with respect to WASH in rural areas and small towns in South Africa—using two case studies to explore climate risk and vulnerability assessment (CRVA) in one rural village in the northern Limpopo province and a small town in the Western Cape province. This holistic approach considered natural (environment and climate) and socio-economic (economic, social, governance, and political) factors and how they interplay in hampering access to WASH. Extreme weather events characterized by frequent and intense droughts or floods aggravate surface and groundwater availability and damage water infrastructure while threatening agriculture-dependent livelihoods. The lack of reliable transport infrastructure increases risks posed by flooding as roads to vital supplies are prone to damage. High inequality linked to rising unemployment and the Apartheid legacy of a segregated service delivery system result in inequitable access to WASH services. The intertwined ways in which natural elements and historical, social, economic, governance, and policy aspects are changing in South Africa increase WASH vulnerability in rural areas and small towns.