Civil Engineering

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The development of a latent heat thermal energy storage system using a phase change material for solar energy application.
(2010) Zulu, Njabulo Mziwandile.; Arnold, David R.
This investigation forms part of an attempt to provide an alternative to conventional power generation technologies that use fossil fuels which have impact on global warming. The field of this investigation covers the development of a latent heat thermal storage system which has a potential of conserving available solar energy. The advantages of using thermal energy storage that have been found previously include reduced energy cost, energy consumption, equipment size and pollutant emissions, also increased flexibility of operation, efficiency and effectiveness of equipment utilization. Traditionally, available heat has been stored in the form of sensible heat (typically by raising the temperature of the energy storage medium) for later use. Latent heat storage on the other hand, is a young and developing technology which has found considerable interest in recent times due to its advantages over sensible heat storage which include smaller temperature swing, smaller size and lower weight per unit of storage capacity. It has been demonstrated that, for the development of a latent heat thermal energy storage system, the choice of the phase change material (PCM) as well as the heat transfer mechanism in the PCM play important roles. In this study, a suitable phase change material and an appropriate heat transfer enhancement technique are identified for utilization in a proposed latent heat thermal energy storage system. Also included, is the design of the proposed heat storage system.
Investigation into the denitrification of high strength landfill leachate using pine bark and raw and composted commercial garden refuse as a carbon source : column studies.
(2010) Browne, A. J.; Trois, Cristina.
Landfill leachate, the liquid discharge from Municipal Solid Waste (MSW) landfills, is the combination of the surface runoff and ground water that percolates through the waste and the liquid contained in the waste itself and is considered to be toxic and presents a potential harm to the environment. Raw leachate contains high concentrations of biodegradable and non-biodegradable carbon as well as high concentrations of ammonia nitrogen. Traditionally, landfill leachate has been treated biologically through aerobic processes which reduce the biological carbon to carbon dioxide and biomass (bacterial growth) and ammonia nitrogen to nitrates. Unfortunately this is not sufficient to protect the environment from harm. It is necessary to further treat the leachate anaerobically to transform the nitrates to elemental nitrogen which is removed from the leachate as nitrogen gas. Biodegradable carbon is often the rate limiting substrate as carbon is consumed during the preceding nitrifying phase. Biodegradable carbon can be supplemented through the addition of methanol, at great expense Leachate from the Mariannhill Landfill site is currently treated aerobically in a sequencing batch reactor where nitrification is achieved. The nitrified leachate is then used as a dust suppressant on the current site. It is anticipated that in 2012 the Land fill site would have reached capacity thereby eliminating the need to irrigate and leaving the site with an excess of nitrified leachate that will present an environmental risk. The denitrifying performance of raw commercial garden refuse, pine bark and composted garden refuse as a growth medium and carbon source was investigated through the establishment of batch and column tests. CGR Raw proved the most successful of the three growth media, achieving full denitrification at a loading rate of 1700 mg NO3-N/kg of substrate/day.
A study on sustainable waste disposal in South Africa using mechanical biological waste treatment.
(2009) Griffith, Mark Richard.; Trois, Cristina.
The landfilling of Municipal Solid Waste poses a threat to the environment in the form of landfill emissions. These emissions are a result of the biochemical breakdown of the waste in the anaerobic landfill environment. A solution to this problem has been found in the form of the mechanical-biological treatment of waste. This technology involves mechanical and biological processing of the waste before it is placed in the landfill. The pretreatment accelerates the degradation of the waste resulting in the landfilling of a more biologically stable product, resulting in a reduction of the emission potential of the landfill. This research aims at investigating the applicability and efficiency of a passively ventilated MBT windrow system under a sub-tropical climate. The research was conducted in two stages: the first stage focused on the implementation and analysis of the Mechanical Biological Treatment (MBT) process with aerobic windrows, employing the Dome Aeration Technology (OAT) (Mollekopf et al. 2002). Three OAT windrows were constructed at the Bisasar Road Landfill in Durban in order to study the efficiency of the process after different composting timeframes (8 and 20 weeks). The study proved that the use of the OAT technology is a viable option. The second stage was the analysis of this treated waste in an anaerobic environment, in order to simulate landfill conditions and, thus gain insight into the effect of MBP on landfill emissions. Six Iysimeters and 5 columns as well as numerous eluate tests were conducted in order to study the "post-Iandfilled" behaviour of the waste and the effect that waste treatment, composting time and screening have on liquid and gaseous emissions. A basic cost estimate using the Clean Development Mechanism for financial assistance was conducted. The results of this research were then utilised to make recommendations on sustainable waste disposal options. The findings of the research were that although the MBT did not reduce emission levels sufficiently to allow for a 40 year landfill aftercare period, the benefit over the landfilling of untreated waste is significant.
An investigation into the mechanical biological pretreatment of garden waste using forced aeration and it impact on carbon emissions reduction potential
(2010-08-31) Iyilade, Yemisi
Disposal of garden waste is a major concern globally and particularly in a developing
Nitrate removal using compost and pine bark as a carbon source.
(2010-09-03) Pisano, Giulia.
Emissions resulting from waste degradation processes have a high polluting potential and are responsible for negative impacts on the environment. Landfill leachate is hazardous for the human health and the environment and requires treatment before being discharged, in order to comply with the South African legislation indicated in the Government Gazette, 1999. However, treated leachate may still contain high levels of nitrate that require an additional denitrification step. Biological denitrification occurs with the addition of a carbon source that increases the operational costs of the process, particularly if chemical compounds are employed (such as methanol). This research aims to explore the efficiency of denitrification using low cost carbon sources such as garden refuse compost and pine bark, easily available in South Africa and currently disposed of in general waste landfills. Denitrification processes in fixed bed reactors were simulated in laboratory scale leaching columns packed with immature compost and pine and irrigated with biologically treated leachate from the Mariannhill landfill site Sequencing Batch Reactor (SBR). The overall objective is to assess efficiency, kinetics and performance of the substrates using batch tests and columns tests. A secondary objective is to assess the feasibility of using organic waste compost and pine bark as by product of an integrated waste management system to denitrify landfill leachate.
Identification, quantification and classification of risks pertaining to building contractors in the JBBCC (Principal Building Agreement)
(2010-09-06) Harinarain, Nishani.
Risks are present in every aspect of business. As one of the biggest industries worldwide, the construction industry is plagued with risks. Being such a large industry, there are hundreds of contracts signed every day. These contracts range from new construction, refurbishment to maintenance. Some projects are simple and worth few thousands of dollars where others are complex and may cost hundreds of millions. Irrespective of how simple or complex the project is, all projects are exposed to risk and can go wrong (Edwards and Bowen, 2005). Construction is governed by complicated contracts and involves complex relationships in several tiers (Abdou, 1996). According to Sawczuk (1996) as soon as the employer and the contractor have signed a contract they have taken on board risks. Their awareness of the risk and the steps to be taken to manage their share of the risk, will determine the likelihood of problems occurring. Construction projects have an abundance of risk, contractors cope with it and owners pay for it. The construction industry is subject to more risk than any other industries. Taking a project from initial investment appraisal to completion and into use is a complex and time-consuming design and construction process. It requires a multitude of people with different skills and a great deal of effort to co-ordinate a wide ranges of disparate, yet interrelated, activities. Inevitably, this complex process is compounded by many unexpected events that may cause loss to the client and other involved parties (Shen, 1999; Flanagan and Norman, 1993). According to Carter et al. (1997) the construction industry is facing a more challenging environment than any time in the past. Client expectations have grown higher and they call for better quality and service. Smith (1998) highlighted that for years the South African building industry had a very poor reputation in managing construction risks. These risks could be prevented or reduced if management takes action at early stages ofthe project life cycle. In order to overcome these limitations and improve the image of the South African construction industry, this research aims to develop an innovative framework to enable construction contractors to identify, quantify and classify the risks associated with the Joint Building Contracts Committee (JBCC) Principal Building Agreement (PBA). This will help making decisions on informed bases. In addition, it will enable contractors develop particular course of actions to mitigate the effects ofthese risks. The research methodology designed to achieve this aim consisted of literature review, questionnaire and interview. Firstly, the literature review was used to review risk management in construction, construction contracts, Risks are present in every aspect of business. As one of the biggest industries worldwide, the construction industry is plagued with risks. Being such a large industry, there are hundreds of contracts signed every day. These contracts range from new construction, refurbishment to maintenance. Some projects are simple and worth few thousands of dollars where others are complex and may cost hundreds of millions. Irrespective of how simple or complex the project is, all projects are exposed to risk and can go wrong (Edwards and Bowen, 2005). Construction is governed by complicated contracts and involves complex relationships in several tiers (Abdou, 1996). According to Sawczuk (1996) as soon as the employer and the contractor have signed a contract they have taken on board risks. Their awareness of the risk and the steps to be taken to manage their share of the risk, will determine the likelihood of problems occurring. Construction projects have an abundance of risk, contractors cope with it and owners pay for it. The construction industry is subject to more risk than any other industries. Taking a project from initial investment appraisal to completion and into use is a complex and time-consuming design and construction process. It requires a multitude of people with different skills and a great deal of effort to co-ordinate a wide ranges of disparate, yet interrelated, activities. Inevitably, this complex process is compounded by many unexpected events that may cause loss to the client and other involved parties (Shen, 1999; Flanagan and Norman, 1993). According to Carter et al. (1997) the construction industry is facing a more challenging environment than any time in the past. Client expectations have grown higher and they call for better quality and service. Smith (1998) highlighted that for years the South African building industry had a very poor reputation in managing construction risks. These risks could be prevented or reduced if management takes action at early stages ofthe project life cycle. In order to overcome these limitations and improve the image of the South African construction industry, this research aims to develop an innovative framework to enable construction contractors to identify, quantify and classify the risks associated with the Joint Building Contracts Committee (JBCC) Principal Building Agreement (PBA). This will help making decisions on informed bases. In addition, it will enable contractors develop particular course of actions to mitigate the effects ofthese risks. The research methodology designed to achieve this aim consisted of literature review, questionnaire and interview. Firstly, the literature review was used to review risk management in construction, construction contracts,
The regional effect of water table lowering in the Durban area
(2010-09-09) Baxter, Brian Thomas.
No abstract available.
The design and development a mechanised support system for tabular stopes.
(2010-09-13) Naidoo, Dushendra.
Towards a zero waste South Africa : a case study on post-consumer solid waste management in rural and urban areas.
(2009) Matete, Ntlibi O.
Through the National Environmental Management Act (No. 107 of 1998), the South African Department of Environmental Affairs and Tourism (DEAT) introduced the concept of the Waste Hierarchy (Reduce - Reuse - Recover - Dispose) as the only possible road towards sustainable development. This concept of sustainable waste management was extended into the Polokwane Declaration on Waste Management which identified Zero Waste as the ultimate goal for sustainable waste management systems in South Africa. Zero Waste is defined as the concept of using all waste produced in a certain area for production activities in that area when it is environmentally acceptable, socially equitable and economically viable, with unavoidable residual waste going to landfill. The aim of this thesis is to test the applicability of Zero Waste to post-consumer waste arising from rural and urban areas. The primary reason that this study has been attempted is that little research in South Africa has focused on the demand-side management of post-consumer waste, and that whatever research that has been undertaken has focused almost exclusively on waste management in urban areas. In order to realise the aim of this thesis, two case studies were selected and analysed: one rural and one urban. These case studies were selected due to differences in characteristics of the waste arising from households, existing waste management systems and socio-economic indicators for households in these areas. In each case study, a proposed Zero Waste Scheme was assessed for application based on four sustainability criteria: environmental, social, economical and institutional. The Zero Waste Schemes are based on the conceptual Zero Waste Model (ZWM) that has been specifically developed as the main tool for conducting this research. The development and use of the ZWM in assessing waste management systems in South Africa is a significant contribution of this thesis to knowledge. Generally, the results showed that the proposed Zero Waste Schemes could meet three of the evaluation criteria used in the investigation, but could not meet the fourth: institutional sustainability. For this reason, the Zero Waste Schemes could not be implemented since the municipalities responsible for waste management in those areas did not have the capacity administrative, financial resources and political will - to implement them. Thus, institutional sustainability has been shown to be the main constraint in the application of Zero Waste Schemes in post-consumer waste management systems in South Africa. This is another significant contribution of this thesis to knowledge.Other significant findings from this study reveal that rural areas lack basic waste collection and disposal systems; hence this lack in service delivery prevents full implementation of Zero Waste Schemes in these areas. In contrast, households in urban areas are served by integrated waste management systems that extend to most households, and most of these households are able to finance the waste management services provided. The existence of the integrated waste management systems was used as a basis for introducing waste minimisation and at-source separation of recyclables in order to reduce the amount of waste needing disposal. Education of households in urban areas has been identified as a key factor in establishing Zero Waste Schemes in the case study areas. In conclusion, it has been shown in this thesis that although Zero Waste Schemes are theoretically applicable to rural and urban areas of South Africa, institutional constraints that will have to be overcome in order to make Zero Waste a reality. Implicit in this conclusion is the extension of waste collection services to rural households and the full participation of rural and urban households in Zero Waste Schemes, participation which can only be verified by actual implementation of the schemes. This is the next step in the approach towards Zero Waste within post-consumer waste management in South Africa.
Investigation of turbidity and chlorine disinfection in South African waters.
(2010-10-19) Moodley, Ubendra.
All natural waters containing particulate matter, such as clay, silt, colloidal particles, plankton
Evaluation of PCI reverse osmosis membrane on landfill leachate.
(2010-10-20) Rambridge, Vischal.
The specific objective of this study was to evaluate a PCI reverse osmosis membrane for
Flood estimation for roads, bridges and dams.
(2010-10-20) Parak, Mohamed.; Pegram, Geoffrey Guy Sinclair.
Flood estimation can be classified into two categories, i.e. flood prediction and flood forecasting. Flood prediction is used for the estimation of design floods, which are floods associated with a degree of risk of being equalled or exceeded. Predictions are needed for the design and construction of infrastructure that are at risk to flowing water. Flood forecasting is used for the estimation of flood flows from an impending and/or occurring rainfall event (i.e. the estimation of the magnitude of future flood flows with reference to a specific time in the future). These are needed by catchment and disaster managers for the mitigation of flood damage. The estimation of flood magnitudes for flood forecasting requires the specific knowledge of prevailing surface conditions which are associated with the processes of rainfall conversion into flood runoff. In order to best achieve this, a distributed model (in order to exploit remotely sensed data and capture the spatial scale of the phenomenon) is used to continuously update the surface conditions that are important in this conversion process. This dissertation focuses on both flood estimation categories. In the first part of the dissertation, attention is given to the improvement of two simple event-based design flood prediction methods currently in use by design practitioners, namely the regional maximum flood (RMF) and the rational formula (RF) by comparison with statistically modelled historical flood data. The second part of the dissertation lays the theoretical and practical foundation for the implementation of a fully distributed physically-based rainfall-runoff model for real-time flood forecasting in South Africa. The TOPKAPI model was chosen for this purpose. This aspect of the research involved assimilating the literature on the model, testing the model and gathering and preparing of the input data required by the model for its eventual application in the Liebenbergsvlei catchment. The practical application of the model is left for a follow-up study.
Long term emission from pre treated waste : column studies.
(2010-10-20) Marchetti, Raffaello.
Emissions resulting from waste degradation processes have a high polluting potential
The characterization of stormwater runoff from road surfaces.
(2006) Chrystal, Clinton Paul.; Stretch, Derek Dewey.
The water quality of stormwater runoff from various road surfaces in Durban, KwaZulu- Natal was characterised by monitoring programmes established at four study areas. The investigation focussed on obtaining representative stormwater samples in order to quantitatively identify pollutant constituents transported within stormwater runoff from road surfaces during rainfall events. Stormwater runoff is a leading cause of degradation in the water quality of receiving water bodies. A review of sampling methods and equipment, informed by the objectives and resources of this investigation, resulted in the development of a stormwater runoff sampler. An economical flow weighted composite sampler was designed, developed and tested. The sampler produces one representative composite event mean concentration sample. Controlled laboratory experiments, computer simulations and field tests were conducted in order to test and calibrate the sampler. The product of the event mean concentration and total runoff volume estimated provide an estimation of the total pollutant loading from a particular drainage area. Twenty stormwater runoff event mean concentration (EMC) and atmospheric deposition samples were collected over an eighteen month period. The characterisation of stormwater runoff for this investigation included heavy metals, oxygen demanding substances, sediments and physico-chemical analysis for pH, conductivity and water hardness. Chemical analysis indicates that the pollutant levels of constituents sometimes exceeded EMCs reported internationally. The majority of contaminant EMCs exceeded the South African wastewater discharge general and special limits. The results also indicate a 60% reduction in lead (Pb) levels since the introduction of lead-free fuel in South Africa in January 2006. The findings from this investigation will provide decision-makers with an improved local data base for estimating the impacts of road transportation systems on water quality. A comparison between the four study areas also provides guidance concerning the variability of stormwater quality from different road surfaces and usage patterns.
Stabilisation of waste in shallow test cells: focus on biogas.
(2006) Chetty, Nevendra Krishniah.; Trois, Cristina.
Present day society generates large volumes of waste that present an environmental hazard when disposed of in landfills. As our population grows, so does the volume of waste generated and hence the threat to our environment. One method of reducing harmful emissions in landfills is the mechanical-biological pretreatment of waste prior to landfilling. The purpose of this dissertation is to investigate the degree of stabilization of waste in shallow landfills (simulated by test cells) with particular focus on biogas production and quality. Municipal waste was composted in aerobic, open windrows for periods of eight and sixteen weeks. Five test cells, designed and operated according to the PAF model (Pretreatment, Aeration and Flushing) were constructed at the Bisasar Road landfill site. These cells were used to simulate large scale municipal landfill sites. They were filled with fresh and pretreated waste and were used to monitor the dynamics of prolonged aeration and degradation of waste over a period of six months. The cells were monitored on a weekly basis while being aerated. Two flushing events were conducted at the beginning of the passive aeration. Gas emissions were also monitored by recording the methane, carbon dioxide and oxygen volumes per volume of air in probes strategically placed in each cell. These results were then analysed to assess the effect of mechanical-biological pretreatment of municipal solid waste on the emission quality of sanitary landfills and the appropriateness of prolonging the aeration in shallow landfills, as often used in sub-tropical countries. It was found that the design of the test cells was appropriate for the landfilling and stabilization of waste that was aerobically treated. After six months in the test cells, analysis of the waste from each cell showed that the waste was completely degraded. The PAF model, when applied to shallow landfills, is very effective in stabilising waste and would be appropriate for a sub-tropical climate. Waste that is pretreated, placed in shallow landfills, initially flushed and then aerated over a six month period was fully stabilized. The requirement for such treatment would be relatively small amounts of waste, a wet climate and the availability of open space for shallow landfills. This method, therefore, would be very appropriate in a South African context. The major problem with this method may be the generation of large quantities of leachate which will have to be treated and disposed of in an environmentally safe manner.
An economic comparison of the waste management schemes employed in Cape Town and Johannesburg.
(2006) Stotko, Oliver.; Trois, Cristina.
The disposal of waste into landfill sites is currently the most commonly employed method of dealing with waste in South Africa as well as internationally. However the global trend towards operating waste management systems in a more sustainable way has lead to the need to reverse this situation towards a waste management system that predominantly makes use of waste minimization schemes to deal with waste and relies minimally on waste disposal. The focus of this research was to determine which waste minimization schemes would be most effective in the Municipal Solid Waste Management Systems (MSWMS) of Cape Town and Johannesburg with regard to achieving this reversal in an economically sustainable manner. The method used to achieve this objective was threefold, firstly requiring the development of a waste flow diagram for each respective city, followed by the development of a waste stream model based on the specific flow diagram and finally the extension of this material model into an economic model. The models were developed in Microsoft Excel and work on the premise that each particular stream (separate collected waste, transfer station waste, etc) of the MSWMS concerned has a particular associated cost (defined as cost per ton of waste processed). The model operates on the principle that under several pre-determined constraints the Excel Solver function calculates the optimal flow rates of the various waste streams which give the minimum overall MSWMS cost for future years. The developed model has shown that the recovery of waste reduces the overall MSWMS costs until a threshold value (at which point under the proposed system all economically recoverable waste has been exhausted). Different waste minimization schemes were found to be appropriate for each respective city. However, the use of Material Recovery Facilities (MRFs) to recover recyclables has been shown to be a viable waste recovery scheme for both Cape Town and Johannesburg. Cape Town is in the process of implementing the development of MRFs in conjunction with existing transfer stations, while it is envisaged that MRFs will be developed on all of Johannesburg's Municipal landfill sites in the future. Significant changes to the MSWMS of both cities are required for their respective landfilling waste streams to be substantially reduced in accordance with the Polokwane Declaration. Decreasing the landfilled waste stream is not only required by legislation, but the developed model has shown that the recovery of waste also reduces the overall MSWMS costs.
Optimization of the construction of VIP toilet sanitation at clinics in rural area.
(2009) Dilrajh, R.; Trois, Cristina.
No abstract available.
The study of the kinetics of degradation of mechanical-biological pretreated waste using test cells.
(2010-11-02) Simelane, Oscar Thamsanqa.
This research was carried out at the Bisasar Road Landfill site, Durban, South Africa,
Environmental impacts of the construction phase of an intensive development project on a coastal forest wetland : case study : Seaward Estates, Ballito.
(2011-01-14) Appelcryn, Anton.; Trois, Cristina.
Storm water runoff is a leading cause of degradation in the water quality of receiving water bodies. Although legislation requires that Environmental Impact Assessments (EIA) are performed and Environmental Management Plans (EMP) put in place for the construction of high density housing developments, there is generally very little evidence that real measures are developed to monitor and actually assess the extent of the impact that construction activities have on the environment during the physical construction stage. The water quality of stormwater runoff from a mixed use catchment including construction sites in Seaward Estates, Ballito, KwaZulu-Natal that enters a coastal forest wetland system was characterised by monitoring programmes established at three study areas. The effect thereof on the quality of the wetland water and sediments was further monitored at five points along the drainage line of the system. The investigation focussed on obtaining representative stormwater samples in order to quantitatively identify pollutant constituents transported within stormwater runoff from construction sites during rainfall events. Storm water runoff event mean concentration (EMC), atmospheric deposition and wetland water and sediment samples were collected over an eight month period. The characterisation of stormwater runoff for this investigation included heavy metals, oxygen demanding substances, sediments and physico-chemical analysis for pH, conductivity and ammonia and nitrates. The majority of contaminant EMC exceeded the South African wastewater discharge general and special limits. The findings from this investigation will provide planners and decision-makers with a greater understanding of the pollution dynamics of construction sites aiding in improved best management practice decisions with regard to minimizing impacts on coastal forest wetlands and water resources. This will lead to improved EMP and stormwater management plans (SWMP) incorporating stormwater pollution prevention plans (SWPPP) for construction sites.
Modelling of the water balance and nutrient dynamics of Mhlanga Estuary.
(2011-01-19) Lawrie, Robynne Angela.
Waste water discharge into a temporary open/closed estuary (TOCE) system introduces two main concerns namely (1) the effects on the water balance of the system (quantity) and (2) the effects on the nutrient dynamics (water quality). Changes to mouth breaching patterns can severely impact the hydrological and ecological functioning of TOCEs, while excessive nutrient loading can lead to eutrophic conditions and algal blooms. Algal blooms occur when residence times during closed mouth conditions exceed the time scale for growth of the microalgal community. The aim of this study was to formulate a model in order to predict eutrophication events using the Mhlanga Estuary as a case study. The Mhlanga Estuary is situated approximately 19 km northeast of Durban and has a small catchment «100km2 ). The Phoenix and Mhlanga waste water treatment works (WWTW) collectively discharge approximately 20MI of treated effluent into the Mhlanga River per day. A simple daily-time-step water balance model was selected to model the hydrodynamics of the system. The model included various inputs and outputs of the system, residence time, storage, breaching water levels and time for mouth closure to occur. The result of the water balance model was a daily prediction of the mouth state and volume, and an indication of the breaching frequency. Observed mouth state data and measured water levels were used to test the model. In order to predict eutrophication events and trends at the Mhlanga Estuary, it was required that the conditions at which this would occur be investigated. This included the collection of samples (physico-chemical and chlorophyll-a) on a weekly basis for three months, a period that included three breaching events. Due to the complexity required in developing a nutrient dynamics model, a simpler approach was selected. The grey water index (GWI) was formulated in order to account for nutrient loadings into the estuary. WWTW discharge data were provided by eThekwini Municipality Water and Sanitation (EMWS). Initial results showed that under ideal conditions, an algal bloom would occur approximately fourteen days following re-closure of the Mhlanga mouth. The eutrophication index (E j ) was then formulated to account for both residence time and nutrient concentrations. The Ej at which eutrophic conditions can be expected was found to be about 50 %. It is important to note that this value for Ej is expected to be site specific and only accounts for the Mhlanga Estuary, but the concept can be generalized to other similar estuaries. Water levels simulated using the water balance model and observed mouth state data produced similar levels to those measured by DWAF. Following simulations of different flow scenarios (75% and 150% increase in WWTW discharges), it was found that an increase in capping flows resulted in more frequent breaching events and longer open mouth conditions. The risk of eutrophic conditions also increased with an increase in WWTW capping flows. Algal blooms are predicted to continue despite more frequent breaching events induced by an increase in capping flows.

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