Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2020 / The present study was carried out in the Kwena Dam, with the aim of determining selected water quality parameters, parasite diversity and condition factor (K) of Clarias gariepinus (sharptooth catfish), Cyprinus carpio (common carp) and Oreochromis mossambicus (Mozambique tilapia). This study was conducted in autumn (April 2016), winter (July 2016), spring (October 2016) and summer (February 2017). The present study was the first to investigate the parasite composition of these three fish species in the Kwena Dam. A total number of 26 Clarias gariepinus, 21 Cyprinus carpio and 57 O. mossambicus specimens were collected using gill nets of different mesh sizes (30 mm – 120 mm). Each fish was weighed, measured and euthanised by severing the spinal cord. Mucus smears from the skin, fins and gills were examined for ectoparasites using a stereo-microscope. The fish were then dissected and all organs examined for endoparasites. All parasites were fixed and preserved according to standard methods for each parasite group. In situ water parameters were determined using a handheld multi-parameter instrument for each sampling season. In addition, water samples were collected seasonally and sent to an accredited laboratory where they were analysed for selected metals and nutrients. Water quality parameters and the presence of metals in water are of importance in determining the water quality of an aquatic environment. Most water quality parameters were within the Target Water Quality Range (TWQR) for aquatic ecosystems. Aluminium, selenium and zinc had concentrations above the TWQR for aquatic ecosystems. Nutrient concentrations were within the TQWR during all sampling seasons. The water quality did not differ significantly between seasons during the present study. Four parasite groups were reported infecting Cyprinus carpio and these included Monogenea (Dactylogyrus extensus and Dactylogyrus minutus), Digenea (Diplostomum sp.), Cestoda (Atractolytocestus huronensis), Branchiura (Argulus japonicus) and Copepoda (Neoergasilus japonicus). Parasites collected from Clarias gariepinus belonged to four groups, namely Protozoa (Trypanosoma sp.), Monogenea (Quadriacanthus sp. and Gyrodactylus sp.), Nematoda (Paracamallanus cyathopharynx and Contracaecum sp.) and Branchiura (Dolops ranarum). Parasites collected from O. mossambicus belonged to five groups, namely Monogenea (Cichlidogyrus halli, Cichlidogyrus sclerosus, Cichlidogyrus tilapiae and Enterogyrus conoratus), Nematoda (Contracaecum sp.), Cestoda (Neogryporhynchus sp.), Acanthocephala (Acanthogyrus tilapiae) and Branchiura (Dolops ranarum). iv The number of parasite species for the four seasons were as follows: summer (13) > autumn and winter (12) > spring (11). From the Shannon-Wiener index results, O. mossambicus had a higher parasite diversity than Clarias gariepinus and Cyprinus carpio. The Parasite Index (IP) and Inverted Parasite Index (IPI) of the three fish species indicated that the water from the dam is not polluted. The condition factor (K) for all fish species indicated that fish collected from the dam during all sampling seasons were in a good condition and parasite load had little effect on K for all fish species. The use of PI and IPI in conjunction with the fish K can be regarded as a useful tool in freshwater and fish health monitoring. The present results report new geographical records of the parasites of Clarias gariepinus, Cyprinus carpio and Oreochromis mossambicus. Since no parasitological research was done before the present study at the Kwena Dam, the results of the present study form baseline data for future parasitology studies and can consequently be useful in the management and conservation of the Kwena Dam. / DSI–NRF SARChI Chair (Ecosystem Health) of the University of Limpopo and the Limpopo Department of Economic Development and Tourism (LEDET)

Thesis (M. Sc. (Zoology)) -- University of Limpopo, 2019 / Many South African rivers, including the Ga-Selati River have been deteriorating for the past few decades, due to an increase in mining, industrial, agricultural and domestic activities. Around mid-January 2014, the Ga-Selati River was contaminated by mine spills from a nearby phosphate mine, which polluted the river and killed many fish species. This river is a primary source of water for many activities (e.g. mining, industrial, agricultural and domestic activities), and as a result, large numbers of reservoirs, farm dams, and inter-basin transfer schemes have been constructed to increase the reliability of water supply along this river. Contamination of surface waters by agricultural pesticides and fertilizers, as well as by industrial metals, is a cause of increasing public concern. The Ga-Selati River is a major tributary for the Olifants River, among other tributaries (Steelpoort River and Blyde River) and it plays a significant role in the Kruger National Park and other private game reserves in the catchment. This River is also known to supply water of very low quality into the main stem of the Olifants River. The Olifants River System has been described as degraded and is contaminated with metal and chemicals, and is considered to be one of the most threatened river systems in South Africa. The aim of the study was to investigate the ecological state of the Ga-Selati River and the impact of water and sediment quality on the aquatic invertebrate communities, and to propose measures to prevent further degradation of the river ecosystem by human disturbance. The main objectives were to: (i) establish the current physico-chemical composition of the river water and sediment along the entire length of the Ga-Selati River, (ii) to determine if poor water quality at the lower end of the river is due to pollution inputs in the lower reaches, or the result of cumulative pollution inputs along the entire length of the river, (iii) Assess the impact of water and sediment quality on the aquatic macro-invertebrate assemblages in the river. The concentrations of pH, and DO were high at all sites. If there was any sort of pollution in the river, especially downstream by the mining sites, we expected these two variables to be lower. The water variables such as EC, TDS and salinity showed a gradual increase from upstream to downstream. There were also elevated levels of certain metals, such as Mg, Na, Ti, B, Sr, K and Ca showing a pollution gradient. The v high concentrations of metals in water samples indicate that the Ga-Selati River is heavily impacted downstream by anthropogenic activities such as illegal dumping/littering at site 6 and mining activities at site 7 to site 9. Some of the metal concentration (Na, Mg, K and Ca) in the river were found to be extremely high compared to other rivers in the region. Metal concentrations in sediment samples were very high compared to water samples River. The nutrient concentrations at the Ga-Selati River were high but did not show a pollution gradient. The macro-invertebrate assemblages in the Ga-Selati River were rich in Ephemeroptera, Diptera and Trichoptera. Site 1 and site 2 accounted for most of the sensitive families, reflecting good water quality at these two sites, while site 9, a downstream site recorded the highest number of tolerant families.. The variations in the macro-invertebrate distribution were shown by the differences in the water quality at the various sites by the CCA plot. The effects of main pollution factors such as, EC, TDS, turbidity and nutrients were correlated with the distribution of tolerant taxa. / National Research Foundation (NRF) and Vlir

The purpose of this study was to determine the chemical content of Denton County's (Texas) water. Based on the analysis of the three samples, the water of Denton County is classed as poor for irrigation.

The purpose of this investigation is to determine the suspended organic matter and the total phosphorus in the waters of Lake Dallas and to evaluate these findings. Since organic matter floating in lakes is largely comprised of minute plants, animals, and detritus derived from animals and plants, the fertilizing effect of phosphorus must be considered as an integral part of this problem.

Municipal separate storm sewer system (MS4) permittees face costly obligations to reduce pollutant loadings needed to achieve waste load allocations (WLAs) and meet total maximum daily loads (TMDLs). Street sweeping is potentially an effective BMP since streets exist throughout urban watersheds, often are directly connected to the storm sewer, and are found to contain an abundance of contaminants. Although pollutant removal from street sweeping has been evaluated for decades, an understanding of the impact on water quality in receiving streams is elusive. Due to numerous variables, the large number of samples necessary to measure impact in receiving streams may never be obtained. In response, modeled pollutant removal efficiencies based on frequency of sweeping have been recommended to the Chesapeake Bay Program, but these results are suspect. Alternatively, the amount of swept material has emerged as a method to quantify reductions. A sampling study was conducted to measure pollutants in swept material. The study identified the fraction of material susceptible to transport in runoff based on timing of sweeping in relation to runoff events. Based on observed pollutant concentration associations with particle size, the study results in estimates of pollutant concentrations for the fraction of material susceptible to downstream transport, dependent on duration since the last rainfall and type of surface swept, whether the area is a streets or a parking lot. Pollutant loadings and required reductions to achieve the Chesapeake Bay WLAs for various land use sample areas are computed for an average year. Modeled removal efficiencies and results from the sampling study were employed to assess impacts from street sweeping. Modeled efficiencies predict significantly lower impact than measurements of pollutants susceptible to runoff in swept material. Modeled loadings are inconsistent with measurements of swept materials and the rigorous sweeping frequency required for modeled removal efficiency credit appears to be unnecessary. / Doctor of Philosophy / Many localities, state agencies and other public entities that own storm sewer systems are increasingly required to reduce pollutants discharged from their systems to surface waters as a result of programs stemming from the Clean Water Act. Traditional stormwater management practices, such as retention ponds, appear limited towards providing the total pollutant reductions necessary due to physical constraints, opportunity and cost. Street sweeping is potentially an effective alternative practice since streets exist throughout urban watersheds, often are directly connected to the storm sewer, are found to contain an abundance of contaminants and can be cost effective. Although pollutant removal from street sweeping has been evaluated for decades, an understanding of the pollutants removed from stormwater is elusive. Past studies suggest the large number of samples necessary to measure impact from sweeping in receiving streams may never be obtained. In response, pollutant removal estimates have been made using computer models, but modeled results are suspect since they cannot be calibrated. Alternatively, a measure of swept material has emerged as a method to quantify pollutant reductions. A sampling study was conducted to measure pollutants in swept material. Results identify the fraction of swept material washed from the swept surface dependent on timing of sweeping in relation to the duration since the last rainfall. Based on observed pollutant concentration associations with particle size, the study results in estimates of concentrations for the fraction of material susceptible to downstream transport, dependent on duration since the last rainfall and type of surface swept, whether the area is a streets or a parking lot. Application of the results are compared to modeled removal efficiencies towards achieving regulatory compliance within various land use sample areas. Modeled efficiencies predict significantly lower impact than measurements of pollutants susceptible to runoff in swept material. Rigorous sweeping frequency required for modeled removal efficiency credit appears to be unnecessary.

This dissertation presents three chapters of contemporary research in environmental and development economics. Each chapter echoes a common theme, in that achievement of regional goals constitute 'Wicked Problems' and that the approaches that parties may take to address these specific regional goals may have complex interactions with other regional goals. Decision-making, cost analysis, and multipurpose efficacy of the approaches that regional parties may take to achieve goals are evaluated in environmental and development contexts and implications for program analysis and policy design are discussed. The first chapter of this dissertation seeks to understand how regulated parties, i.e. Municipal Separate Storm Sewer Systems (MS4s), choose from the strategies at their disposal to achieve compliance with their Chesapeake Bay Total Maximum Daily Load (TMDL) obligations. To address declining Chesapeake Bay water quality, the United States Environmental Protection Agency (EPA) set extensive nutrient and sediment reduction goals under the 2010 Chesapeake Bay TMDL. Virginia has responded by passing along explicit nutrient and sediment reduction requirements to its MS4s, which can choose from a variety of urban stormwater, land use change, source control, and restoration practices to achieve reductions toward these requirements. MS4s in Virginia have also been granted flexibility to achieve reduction requirements through purchase of nutrient and sediment credits toward requirements through trade. In spite of the cost-savings that these credits provide, MS4s' interest in trading for these credits has been low. MS4s instead generally engage in onsite nutrient and sediment reduction themselves, in spite of the high costs of doing so. In response to low interest in trade, case analysis of MS4s' Bay TMDL compliance behavior and semi-structured interviews are conducted to better understand the role of trade in compliance strategy and the reasons for its non-use. Findings reveal that the Virginia MS4s studied typically choose to implement onsite urban stormwater practices, source control practices, and restoration practices in order to generate long-lasting local benefits, like erosion control, flood risk reduction, and progress toward local TMDL obligations, alongside reductions toward the Bay TMDL. MS4s refrain from term credit purchases out of concern over future availability and refrain from perpetual credit purchases because they have been able to use funding sources to achieve reductions from long-lasting onsite practices at similar per-pound costs, while also receiving local benefits. Implications are that supply-side efforts to support trade markets may not generate the level of activity expected, given that would-be buyers have generally limited interest in trade as a compliance strategy. The second chapter studies the degree to which the practices used to meet local TMDL water quality obligations contribute to Bay TMDL compliance for the Loudoun County MS4. Linear programming is used to estimate the minimal cost of achieving Bay compliance in addition to local obligations through representative nutrient and sediment reduction strategies. The model estimates that Loudoun County MS4 faces substantial costs just to meet local water quality goals ($11 million/yr). Since many of the actions taken to meet local water quality goals also generate pollutant reductions to the Chesapeake Bay, adding Bay TMDL obligations adds 0.2%, 3%, and 32.9% to these costs, depending on the water quality trading used to reach Bay TMDL compliance. Findings shed additional light on Chapter 1's goal of investigating the role of trade by explaining low interest in trade as stemming from heavy local water quality needs. Implications are that the burden imposed by the Bay TMDL may not be as high as generally thought. The third chapter shifts focus to the Opioid Crisis to evaluate the efficacy of Syringe Exchange Programs, best known for their efforts to prevent bloodborne illness transmission, at achieving their secondary intervention goal of preventing opioid overdose. While research has established that Syringe Exchange Programs, or SEPs, are effective at preventing bloodborne illness, little focus has been given to their ability to prevent fatal overdose, which they aim to do by engaging in intervention practices like naloxone and fentanyl test strip distribution. In response for need for understanding of Syringe Exchange Programming's impact on overdose, fixed effects analysis is used to empirically study the impact of county-level SEP in North Carolina following the state's 2016 SEP legalization. Need-based programming complicates analysis and likely biases findings of the impact of SEP on overdose upward. Regardless, findings consistently fail to find that SEP has a significant effect on fatal overdose from four categories of opioids, which should reduce concerns in recent literature that they may increase overdose death. Implications are that, since SEPs have a richly documented history of saving lives through the prevention of bloodborne illness and do not appear to increase overdose, contrary to findings in other work, policy makers should continue to incorporate SEP into their portfolio of strategies used to address the Opioid Crisis. / Doctor of Philosophy / This dissertation presents three chapters of contemporary research in environmental and development economics. Each chapter echoes a common theme, in that achievement of regional goals constitute 'Wicked Problems' and that the approaches that parties may take to address these specific regional goals may have complex interactions with other regional goals. Decision-making, cost analysis, and multipurpose efficacy of the approaches that regional parties may take to achieve goals are evaluated in environmental and development contexts and implications for program analysis and policy design are discussed. The first chapter of this dissertation seeks to understand how regulated parties, i.e. Municipal Separate Storm Sewer Systems (MS4s), choose from the strategies at their disposal to achieve compliance with their Chesapeake Bay Total Maximum Daily Load (TMDL) obligations. To address declining Chesapeake Bay water quality, the United States Environmental Protection Agency (EPA) set extensive nutrient and sediment reduction goals under the 2010 Chesapeake Bay TMDL. Virginia has responded by passing along explicit nutrient and sediment reduction requirements to its MS4s, which can choose from a variety of urban stormwater, land use change, source control, and restoration practices to achieve reductions toward these requirements. MS4s in Virginia have also been granted flexibility to achieve reduction requirements through purchase of nutrient and sediment credits toward requirements through trade. In spite of the cost-savings that these credits provide, MS4s' interest in trading for these credits has been low. MS4s instead generally engage in onsite nutrient and sediment reduction themselves, in spite of the high costs of doing so. In response to low interest in trade, case analysis of MS4s' Bay TMDL compliance behavior and semi-structured interviews are conducted to better understand the role of trade in compliance strategy and the reasons for its non-use. Findings reveal that the Virginia MS4s studied typically choose to implement onsite urban stormwater practices, source control practices, and restoration practices in order to generate long-lasting local benefits, like erosion control, flood risk reduction, and progress toward local TMDL obligations, alongside reductions toward the Bay TMDL. MS4s refrain from term credit purchases out of concern over future availability and refrain from perpetual credit purchases because they have been able to use funding sources to achieve reductions from long-lasting onsite practices at similar per-pound costs, while also receiving local benefits. Implications are that supply-side efforts to support trade markets may not generate the level of activity expected, given that would-be buyers have generally limited interest in trade as a compliance strategy. The second chapter studies the degree to which the practices used to meet local TMDL water quality obligations contribute to Bay TMDL compliance for the Loudoun County MS4. Linear programming is used to estimate the minimal cost of achieving Bay compliance in addition to local obligations through representative nutrient and sediment reduction strategies. The model estimates that Loudoun County MS4 faces substantial costs just to meet local water quality goals ($11 million/yr). Since many of the actions taken to meet local water quality goals also generate pollutant reductions to the Chesapeake Bay, adding Bay TMDL obligations adds 0.2%, 3%, and 32.9% to these costs, depending on the water quality trading used to reach Bay TMDL compliance. Findings shed additional light on Chapter 1's goal of investigating the role of trade by explaining low interest in trade as stemming from heavy local water quality needs. Implications are that the burden imposed by the Bay TMDL may not be as high as generally thought. The third chapter shifts focus to the Opioid Crisis to evaluate the efficacy of Syringe Exchange Programs, best known for their efforts to prevent bloodborne illness transmission, at achieving their secondary intervention goal of preventing opioid overdose. While research has established that Syringe Exchange Programs, or SEPs, are effective at preventing bloodborne illness, little focus has been given to their ability to prevent fatal overdose, which they aim to do by engaging in intervention practices like naloxone and fentanyl test strip distribution. In response for need for understanding of Syringe Exchange Programming's impact on overdose, fixed effects analysis is used to empirically study the impact of county-level SEP in North Carolina following the state's 2016 SEP legalization. Need-based programming complicates analysis and likely biases findings of the impact of SEP on overdose upward. Regardless, findings consistently fail to find that SEP has a significant effect on fatal overdose from four categories of opioids, which should reduce concerns in recent literature that they may increase overdose death. Implications are that, since SEPs have a richly documented history of saving lives through the prevention of bloodborne illness and do not appear to increase overdose, contrary to findings in other work, policy makers should continue to incorporate SEP into their portfolio of strategies used to address the Opioid Crisis.

No description available.

This research addresses the Reference Watershed Approach (RWA) in the TMDL process for benthic impairments. In the RWA, do different land use sources (DOQQ and NLCD) or use of alternative water quality models (GWLF and SWAT) result in different stressor loadings? Is there a difference in stressor loadings when different reference watersheds are used? Study results showed that using different land use sources resulted in required stressor reductions that were different by greater than 10%. In one scenario, use of the NLCD-based land use parameters results in 3.5 times greater reductions than use of DOQQ-based land use parameters. With respect to water quality model selection, in two of the three scenarios considered, a difference in stressor reduction requirements of greater than 10% resulted from using different models. Differences in load reduction requirements are also seen when different reference watersheds are used, regardless of the water quality model or the land use source used. Different references result in a difference of as much as 73% in required sediment reductions in the impaired watershed: the required reductions using one reference watershed are 6.2 times as great as when another is used. Possible alternatives to the RWA include water quality standards to set the target level for many of the common stressors on the benthic assemblage, regression equations that relate benthic stressors to the RBP II score, or averaging of stressor reduction requirements obtained from using the Reference Watershed Approach on several different reference watersheds. / Master of Science

Thesis (MEng)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The Berg River is one of the largest rivers in the winter rainfall area of the Western Cape and is one of the most important water supply sources of the area. The Riviersonderend-Berg system needs to be expanded in order to meet increasing water demands of the Greater Cape Town (GCT) region. The implementation of future schemes will remove additional fresh water from the Berg River main stem, which will give rise to increased nutrient levels and higher salinity in the water. A water quality information system (WQIS) has been proposed to benefit the management of water resources, the flow quantity and the quality of the water. A part of this WQIS will be a water-quality simulation model that characterizes the water quality situation and is able to predict water quality responses to future implementations, as well as simulate different scenarios that can be used for management purposes. The objective of this study is to represent the water quality situation of the Berg River in a simulation model by implementing, testing and verifying a water quality simulation model, and assembling a hydraulic and water quality database suitable to meet foregoing objectives. This study firstly examined the water quality variables of concern: pH, Total Dissolved Salts (TDS) and phosphates to develop an understanding of the water quality responses and causes of the main stem of the Berg River system. A thorough review of the available models has been undertaken in the light of certain selection criteria, before determining that DUFLOW would be an acceptable model for this study. The water quality variables that have been modelled are TDS, Phosphates as P04, Oxygen and Temperature. As no predefined module simulating temperature, TDS and COD was included; these algorithms, describing the processes of these water quality variables have been additionally coded. The coding was possible, as DUFLOW' s water quality module consists of an open structure. The predefined water quality module was simplified to only include the water quality process algorithms, for water quality variables where data was available. Unfortunately, phosphates were mainly simulated on advection, and the influence of all the additional processes could not be assessed. All data gathering and preparation for the model had to be completed before commencing the model configuration. This included information on cross-sections, historical flow records, bridges and weirs for the hydraulic component ofDUFLOW. For the water quality module, information on historical grab samples has been obtained and 'infilled' to provide daily time series. To simulate the water quality in a river as accurately as possible, the flow simulation needs to be accurate. Ungauged subcatchment runoff was added to the simulation model to improve the correspondence between the simulated and the measured flow. Calibration of the water quality part of DUFLOW was completed by adjusting the different parameters after a sensitivity analysis. The model was verified by using a different time period than for the configuration, to ensure that an independent data set has been used. After configuring, calibrating and verifying the model, the applicability of the model could be tested for different scenario runs. Three scenarios were chosen according to real situations: • a short term effluent spill, with and without water releases from an upstream source (either Skuifraam Dam or Voëlvlei Dam); • the impact on the flow and water quality situation of the river when an upstream dam is built; • a long term management control scenario, that analyses load or concentration releases into the river according to limitations upstream and downstream of the discharge location. The scenario analysis provides an opportunity to assess the applicability of DUFLOW to simulate real time management and operational issues in a river and to aid in management decisions. / AFRIKAANSE OPSOMMING: Die Bergrivier is een van die grootste riviere in die winterreënvalgebied van die Weskaap en is een van die mees belangrike waterverskaffingsbronne in die area. Die Riviersonderend-Bergrivier-stelsel moet uitgebrei word om aan die groeiende waterbehoefte van die groter Kaapse Metropolitaanse Area te voldoen. Die implementering van toekomstige skemas sal addisionele vars water uit die hoof-loop van die Bergrivier onttrek, wat tot hoër voedingstof-vlakke en soutgehalte in die water sal lei. 'n Waterkwaliteitsinformasiestelsel (WQIS) sal van nut wees om die vloei-omvang en waterkwaliteit van waterbronne te bestuur. 'n Deel van die WQIS sal 'n waterkwaliteit-simulasiemodel wees, wat die waterkwaliteitsituasie sal kan ontleed, waterkwaliteit-reaksies op toekomstige implementerings kan voorspel, asook verskeie scenarios vir bestuursdoeleindes kan simuleer. Hierdie studie behandel spesifiek die waterkwaliteitsveranderlikes pH, totale opgeloste soute, fosfate, temperatuur en suurstof om 'n begrip te ontwikkel van die waterkwaliteitsreaksies en oorsake van die hoofloop van die Bergriviersisteem. Die doelwit van hierdie studie is om die waterkwaliteitsituasie van die Bergrivier uit te beeld deur die implementering, toets en kalibrasie van 'n waterkwaliteit-simulasie model, asook die insameling van hidrouliese- en waterkwaliteitsdata om aan bogenoemde doelwitte te voldoen. 'n Reeks beskikbare modelle is deeglik ondersoek voordat besluit is dat die DUFLOW model 'n gepaste model vir hierdie spesifieke studie is. Die keuse was gebaseer op spesifieke vereistes wat as belangrik beskou is deur potensiële bestuursgeorienteerde gebruiksgroepe. Die waterkwaliteitsveranderlikes wat gemodelleer is, is totale opgeloste soute, fosfate as P04, suurstof en temperatuur. Omdat geen voorgegewe temperatuur-, TDS- en COD modules in die model ingesluit is nie, is die algoritmes wat die prosesse van hierdie waterkwaliteitsveranderlikes beskryf, addisioneel gekodeer. Die kodering is moontlik gemaak deur die oop struktuur van DUFLOW se waterkwaliteitsmodule. Die voorgegewe waterkwaliteitsmodule is vereenvoudig om alleenlik die waterkwaliteit proses-algoritmes in ag te neem wanneer data vir waterkwaliteitsveranderlikes beskikbaar was. Ongelukkig is die fosfate hoofsaaklik op beweging gesimuleer, en die invloed van alle addisionele prosesse kon nie getoets word nie. Alle data-insameling en -voorbereidings vir die model moes voltooi word, voordat begin kon word met die opstel van die simulasie-model. Dit het inligting oor dwarssnitte, historiese vloeirekords, brik en keerwalle vir die hidrouliese komponent van DUFLOW ingesluit. Vir die waterkwaliteitsmodule is inligting van historiese bemonstering verkry en ingevulom 'n daaglikse tydreeks te verkry. Om die water-kwaliteit van 'n rivier so akkuraat as moontlik te simuleer, moet die vloei-simulasie redelik akkuraat wees. Ongemete sub-opvanggebied afloop is bygetel om die korrelasie tussen die gesimuleerde en gemete vloei te verbeter. Kalibrasie van die waterkwaliteitmodule van DUFLOW is voltooi deur die verskillende parameters te verstel na 'n sensitiwiteits-analise. Die model is geverifieer deur 'n ander tydperiode as die vir die opstel te gebruik, om sodoende te verseker dat Inonafhanklike data stel gebruik word. Na die opstel, kalibrasie en verifiering van die model, kon dit toegepass word vir verskillende bestuursscenanos. Drie scenarios is na aanleiding van werklike situasies gekies: 'n korttermyn uitvloeisel storting-situasie met en sonder loslatings van 'n stroomop bron (Of Skuifraamdam Of Voëlvleidam), die impak op die vloei- en waterkwaliteitsituasie van die rivier sou 'n dam stroomop gebou word. 'n langtermyn bestuurs-scenario waarin die lading en konsentrasies, veroorsaak deur die loslatings vanuit die dam na die rivier, ontleed word na aanleiding van beperkings stroomop en -af van die loslatingsplek. Die analise van die scenarios verskaf 'n geleentheid om die toepaslikheid van DUFLOW te ondersoek om werklike operasionele aangeleenthede te simuleer en om sodoende bestuursbesluite te vergemaklik.

In low-resource contexts, household-level point-of-use water treatment (POUWT) techniques are the final, and sometimes only, barrier against waterborne illnesses, and in these and other water-related applications, health risks can be quantified using one of two methods. Firstly, Escherichia coli (or other indicator organism) counts can be used to monitor water and determine adherence to a health-based limit (i.e. compliance monitoring). Secondly, E. coli can be used to conduct a quantitative microbial risk assessment (QMRA), indicating the level of protection conferred by a given POUWT device by spiking test water with E. coli to ascertain a reduction efficacy relative to that target organism, a process referred to as challenge testing, which is typically carried out in a laboratory context. Although both methods are well established, both have scope for improvement for effective field application in low-resource contexts. Regarding compliance monitoring, I assessed the performance of a new low-cost field kit for E. coli enumeration, which was designed by others. I also assessed the feasibility of re-using some disposable materials, in terms of sterility and mechanical wear. The use of the new low-cost field kit was successful during the fieldwork campaign; however, re-using disposable materials introduced a relatively high occurrence of false positive results during E. coli enumeration. Use of the new low-cost field kit can reduce financial barriers, thus enabling greater water quality testing coverage. Regarding challenge testing, the aim of this study was to adapt current protocols to assess the household performance (as opposed to laboratory performance) of POUWT techniques. I developed a conceptual framework to conduct Field Challenge Tests (FCT’s) on POUWT techniques, using a probiotic health supplement containing E. coli as the challenge organism. I successfully carried out a FCT in Malawi with limited resources, verifying FCT viability. Applications of such FCT’s include quality control practices for manufactured devices, guiding QMRA and recommendations by public health organizations regarding POU device selection, and assessing the impact of user training programmes regarding POUWT techniques. / Graduate