Vapour pressure (interchangeably referred to as atmospheric humidity) and solar radiation data are, for different reasons, difficult data to obtain in South Africa. Relative humidity measuring instruments (from which vapour pressure values can be obtained) require constant maintenance , while solar radiation can only be measured electronically. Data from both of these variables are, however, required as inputs to the Penman-Monteith equation, which has become the internationally accepted reference for the estimation of potential evaporation. It is necessary, therefore, to produce estimates of vapour pressure and solar radiation over South Africa from more common surrogates, e.g. rainfall and temperature data. Several methods of estimating vapour pressure and solar radiation from the literature are reviewed in this dissertation. Considerably greater attention is focused on models of vapour pressure than solar radiation , as less literature exists on this subject. In general, the methods involved in estimating vapour pressure tend to be relatively rudimentary. The FAO 56 documentation advises using saturated vapour pressure at minimum air temperature as an estimate of vapour pressure, yet the implicit assumptions of using this approach can fail in many circumstances, particularly in the more arid regions . It was found that monthly vapour pressure at any given location in South Africa could be estimated from geographical (invariate) data alone. It was also found that the most influential factor affecting daily vapour pressure at a given location within a given time frame (less than one month) was "air masses". Air masses proved too complicated to model from surrogate data of temperature and rainfall , however, and were thus omitted from the final model. Daily values of vapour pressure and vapour pressure deficit were estimated by holding vapour pressure for a given month constant, but varying temperature on a daily basis It was found that this method produced acceptable results for both elements throughout South Africa. The need for estimating solar radiation has existed for considerably longer than for vapour pressure. Professions other than agriculture, principally architecture and civil engineering, have long required solar radiation data/values. For this reason the art of estimating solar radiation values is better established and more models were available in the literature. Several suitable and recently developed solar radiation models, which use surrogate data (temperature and rainfall) , were identified from the literature survey. These models were then applied in situ and the results were compared with observed values. It was found that the majority of models produced similar output to one another. However, the Liu and Scott (2001) model, which is an enhancement of the Bristow and Campbell (1984) model, was found to be the best available model of those tested, particularly in the more humid locations of South Africa . Verification analyses revealed that the Liu and Scott (2001) model could be used to interpolate solar radiation where a sparse network of solar radiation measuring stations exists, e.g. in the arid locations of South Africa . The structure of the Liu and Scott (2001) model , however, prevented it from being employed in a subsequent exercise on mapping solar radiation over South Africa . For this purpose, the Hunt et al . (1998) model was employed. The estimation of two elements , vapour pressure and solar radiation , was improved upon, and the Penman-Monteith equation can thus now be more confidently applied throughout South Africa. Of these two elements, it is vapour pressure , which, because of a paucity of research to date on the subject, lends itself to expansive research in the future . / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Problems in the water sector range from degradation and depletion of water resources as a result of the impacts of land based anthropogenic activities, to the impacts of natural hydrological disasters and floods, while inadequate availability of water is at the core of most water related disputes in arid and semi-arid areas at local, regional, national and international levels. In the past, finding practical solutions for these problems fell neatly within the traditional scope of water resources management, which hinged almost entirely on economic viability of engineering oriented endeavors. However, a new set of management challenges has arisen following the high priority nowadays given to equity in water allocation and the protection of the natural environment above other issues. These new challenges have created a need for devising and adopting suitable management approaches, especially that would take social considerations into account. One of the approaches that provides promise relative to the new directions in dealing with contemporary water issues is integrated water resources management (IWRM). One objective of this study was to critically review the definitions and the fundamental principles of IWRM with the view of determining its applicability in developing countries and highlighting difficulties that may be faced regarding the adoption and implementation of this integrated approach. Swaziland is atypical example ofa developing country that is engulfed by the diverse water resources issues highlighted above and is currently engaged in updating water management legislation. Hence, Swaziland's experiences were used to put in perspective the key points and barriers regarding the adoption and implementation of IWRM. The catchment, the recommended spatial unit of IWRM, poses the first practical barrier, as catchments often cross both political and administrative boundaries, thereby creating the need for many water management problems to be solved across catchments with international security issues, cultural issues, different levels of development and different hydroclimatic regimes. The successful implementation of IWRM depends on effective participation of stakeholders. Lack of information flow between stakeholders of different backgrounds limits informed participation. Therefore, it is necessary to develop tools such as decision support systems (DSSs) that will foster easier multilateral information flow and aid decision making. IWRM requires information which itself should be managed in an integrated manner and be readily accessible. This is not always the case in developing countries with shortage of funds for data collection, manipulation and storage as well as adequately trained and experienced staff With the shortage of sufficiently long and reliable hydrological data for water management, the alternative is to synthesize records through hydrological modelling. Another objective of this study was to evaluate and test the suitability of the ACRU modelling system, a daily time-step agrohydrological model, to simulate catchment level hydrological processes and land use impacts as part of the assessment studies which form an integral part of integrated water resources management. ACRU was set up for the Mbuluzi, a 2958 km2 catchment in Swaziland. The catchment was subdivided into 40 sub catchments, after which the model was used for assessing both the impacts of land use and management changes on runoff yields and available water resources by evaluating present and future sectoral water demands, determining whether river flow from Swaziland into Mozambique meets the quantitative requirements of the international agreement existing between the two countries, and evaluating sediment yield and its spatial and temporal variation as well as its response to potential changes in land management. The physical-conceptual structure of the model, its multi-level adeptness regarding input information requirements, coupled with in-built decision support systems and generic default values make ACRU a suitable modelling tool in developing countries, as it makes it possible to obtain reasonable simulations for a range of levels of input information. Together with the model's multi-purpose nature, the ability of simulating ''what if scenarios", which was utilised in this study, makes it useful in the generation of information for IWRM. Future research needs which were identified include finding means of encouraging effective communication between scientists, water managers and other stakeholders, who may be "lay people". There is a need to conduct research that will lead to equipping ACRU with sediment routing and deposition algorithms, as well as routines to account more explicitly for dam operating rules and ecological issues, which would render its output even more useful in IWRM than the model's present structure allows. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

South African commercial plantations occupy an estimated 1.5 million hectares of the country and as the demands for timber products increase, this area is expected to increase. However, further expansion is limited, not only by the suitability of land, but also by the pressures from other water users. As a result the need has arisen for simulation models that can aid decisionmakers and planners in their evaluation of the water requirements of forestry versus competing land uses at different spatial scales. Different models exist to perform such tasks and range from simple empirical models to more complex physically-based models. The policies of the National Water Act (1998) relating to forestry serve to highlight the requirements of a model used for the assessment of afforestation impacts and these are discussed in this document. There is a perception that physically-based distributed models are best suited for estimation of afforestation impacts on a catchment's water yield since their physical basis allows for extrapolation to different catchments without calibration. Furthermore, it is often stated that the model parameters have physical meaning and can therefore be estimated from measurable variables. In this regard, a review of physically-based modelling approaches and a comparison of two such hydrological models forms the main focus of this dissertation. The models evaluated were the South African ACRU model and the Australian topography-based Macaque model. The primary objective of this research was to determine whether topography-based modelling (Macaque model) provides an improved simulation of water yield from forested catchments, particularly during the low flow period, compared to a physically-based model (ACRU model) that does not explicitly represent lateral sub-surface flow. A secondary objective was the evaluation of the suitability of these models for application in South Africa. Through a comparison of the two models' structures, the application of the models on two South African catchments and an analysis of the simulation results obtained, an assessment of the different physically-based modelling approaches was made. The strengths and shortcomings of the two models were determined and the following conclusions were drawn regarding the suitability of these modelling approaches for applications on forested catchments in South Africa:• The ACRU model structure was more suited to predictive modelling on operational catchments, whilst the more complex Macaque model's greatest limitation for application in South Africa was its high input requirements which could not be supported by the available data. • Despite data limitations and uncertainty, the Macaque model's topography-based representation of runoff processes resulted in improved low flow simulations compared to the results from the ACRU simulations, indicating that there are benefits associated with a topographically-based modelling approach. • The Macaque model's link to the Geographic Information System, Tarsier, provided an efficient means to configure the model, input spatial data and view output data. However, it was found that the ACRU model was more flexible in terms of being able to accurately represent the spatial and temporal variations of input parameters. Based on these findings, recommendations for future research include the. verification of internal processes of both the ACRU and Macaque models. This would require the combined measurement of both catchment streamflow and processes such as evapotranspiration. For the Macaque model to be verified more comprehensively and for its application in operational catchments it will be necessary to improve the representation of spatial and temporal changes in precipitation and vegetation parameters for South African conditions. / Thesis (M.Sc.)-University of Natal ,Pietermaritzburg, 2002.

This thesis describes the development of a decision support tool to be used in the operation of Vanderkloof Dam on the Orange River so that the supply of water to the lower Orange River can be optimised. The decision support tool is based on a hydrodynamic model that was customised to incorporate real time data recorded at several points on the river. By incorporating these data into the model the simulated flows are corrected to the actual flow conditions recorded on the river, thereby generating a best estimate of flow conditions at any given time. This information is then used as the initial conditions for forecast simulations to assess whether the discharge volumes and schedules from the dam satisfy the water demands of downstream users, some of which are 1400km or up to 8 weeks away. The various components of the decision support system, their functionality and their interaction are described. The details regarding the development of these components include: • The hydraulic model of the Orange River downstream of Vanderkloof Dam. The population and calibration of the model are described. • The modification of the code of the hydrodynamic engine so that real time recorded stage and flow data can be incorporated into the model • The development of a graphical user interface to facilitate the exchange of data between the real time network of flow gauging stations on the Orange River and the hydraulic model • The investigation into the effect of including the real time data on the simulated flows • Testing the effectiveness of the decision support system. / Thesis (M.Sc.)-University of Natal, Durban, 2002.

The challenges facing small scale irrigation development in South Africa are varied and complex. This complexity is exacerbated by the many years of systematic neglect, in tandem with material and intellectual impoverishment of the majority of participants in this agricultural sector. Attempting to juggle sustainable development of small scale agriculture and environmental and socio-economic advancement is difficult, but there is sufficient evidence in the literature to suggest that small scale agriculture is increasing not only in South Africa but in Sub-Saharan Africa (Collier and Field, 1998) There is no doubt that this observed increase in irrigated communal gardens result from their increasingly important role of providing food security and as means of augmenting family income. Hence the government,NGO' s and other private sector organisations have increased their support for these small scale agricultural initiatives. Small scale agriculture is therefore increasingly becoming a common land use, and with this increased support, it is likely to become a major water user, particularly as it is located in close proximity to the water source. Hence both practices and processes for small scale agriculture require careful study. Irrigation practices have been studied in KwaZulu-Natal where small scale community gardens are continuously developing. The study included two locations near Pietermaritzburg. The first, at Willowfontein, involved irrigation by furrow , and the second, at Taylors Halt, involved irrigation by hand, using containers. The dynamics of the subsurface flow was monitored using tensiometry and modelled in detail using a two dimensional, soil physics model, Hydrus-2D, to evaluate the application efficiency. This study consisted of three parts viz: socio-economic system appraisal, technical measurement and monitoring, and modelling. Important findings obtained include the following: The highlighting of pertinent socio-economic issues governing water use and allocation and other operations in developing small scale agricultural conditions, including constraints to the development of this sector under the conditions described. The demonstration of the use of reasonably inexpensive, but sophisticated measuring techniques to observe the soil water processes in small scale community gardening practices. Accurate simulations of soil water infiltration,redistribution and uptake using the Hydrus2D model. With these successful simulations, together with the results of the social system appraisal, more efficient irrigation scenarios are proposed and evaluated. The development of a methodology that could be used to assess small scale irrigation efficiencies, with computer simulation models used as tools to conduct such an assessment. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Non point source pollution (NPS) has long been the negated form of pollution within our natural systems. With an increase in the demand for quality crops and staple foods, there have been added pressures on water systems to cope with increasing NPS pollution (NPS-P). The effect and importance of scale on the assessment of NPS pollution has been identified as a pivotal component in the assessment of such pollutants, in particular the translation of processes from a field to a catchment scale. It has therefore become important to further investigate and research the processes involved in transporting and retaining pollutants at each measurement scale. A number of models have been developed for simulation catchments, however none of the suitably address the issue of NPS pollution and the translation of processes from the field through to the catchment scale. Each model researched fails to effectively address processes over varying scales, and tend to concentrate on a particular scale of observation. There is a distinct lack of a capable mechanism that assesses NPS pollution across varying scales within a catchment. The Water Research Commission (WRC) NPS-P project aims at eventually developing a successful model that addresses the issue of assessing NPS pollution across a number of different scales. This study aimed at assessing the loads of sediments and nutrients at different scales and included the establishment of a research catchment in the Mkabela Catchment outside Wartburg in KwaZulu-Natal, and the collection and interpretation of rainfall, runoff and nitrate data for a full year of sampling. The sampling provided valuable data for the calculation of pollutant masses and concentrations within the Mkabela Catchment. Non Point Sources are generally more dilute with suspended solids and nitrate in particular tending to have a high transport dependence upon summer events with a high intensity and low duration. A varying degree of scales were monitored during this study, ranging from plot to catchment scale in order to assess the varying influences on NPS Pollution (Nitrate and Suspended Solids). Monitoring was conducted through research mechanisms ranging from runoff plots at the plot scale to catchment scale flumes. It was found that scale has a varying influence on NPS pollution, with pollutant concentrations measured to be at a maximum at the field scale, with a value of 13.54mg/l of nitrate measured within the cane fields from event 3. Suspended solid values taken from within the water samples were most apparent at the plot scale, within the runoff plots, with a maximum of 2866.7mg/l measured during event 3 as well. It was evident from measurements and results obtained for each of the 10 sampled events that the main influencing factor of the nitrate concentrations and suspended solid values was the nature of the event. Summer rainfall events (high intensity and short duration) provided large overland flow volume that contributed largely towards the high concentrations of both nitrate and suspended solids, whereas the winter rainfall event (low intensity and long duration) contributed little to the concentrations of nitrate and suspended solids. In contrast to nitrate concentration, the largest nitrate loads by mass were measured during event 1 at the large catchment scale (Bridge 2), with a total cumulative load of 74.17kg nitrate estimated to have been yielded at the catchment outlet. The majority of nitrate are yielded from the agricultural lands where farming practices lead to the application of chemicals preplanting and post emergence. Suspended solids displayed a similar trend to that of nitrate, with an increasing cumulative yield measured throughout the catchment, resulting in a total 13414kg of sediment being measured at Bridge 2. It is interesting that Event 1 measured the largest cumulative loads for both nitrate and suspended solids; however it was recorded as an average intensity event (19.1mm/h) in comparison to the largest sampled intensity event of 165.9mm/h (Event 4) during the study. This may be attributed to the fact that the event coincided with the planting schedule of the sugarcane crops, and so the bare nature of the agricultural fields resulted in increased overland flow, and hence nitrate and suspended solid transportation. Data collected during all the events clearly show that the impoundment (a farm dam) acts as a water quality filter by retaining many of the nitrate pollutants when they enter the dam as channel flow. In summary, the controlling processes governing NPS-P movement varied through the differing scales, with crop size, artificial chemical application, nature of the event and timing during the year all contributing in varying manners at the differing scales. Future research within the WRC-NPS-P project should continue with sampling from the designated research points and add several more seasons of data to the already comprehensive first season of sampling. In addition, once a reasonable number of seasons have been sampled and analysed within the Mkabela Catchment, the initiation and development of an effective, representative scaled NPS-P model that addresses the movement and retardation of pollutants is necessary to be able to successfully model and predict the movement of NPS-P through catchment systems. In particular the effects of the controls afforded by such features as road crossings, wetlands and farm dams should be taken into account in the modelling of sediment and nutrient movement from field to catchment scale. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

There is a frequent need for estimates of design floods by hydrologists and engineers for the design of hydraulic structures. There are various techniques for estimating these design floods which are dependent largely on the availability of data. The two main approaches to design flood estimation are categorised as methods based on the analysis of floods and those based on rainfall-runoff relationships. Amongst the methods based on the analysis of floods, regional flood frequency analysis is seen as a reliable and robust method and is the recommended approach. Design event models are commonly used for design flood estimation in rainfall-runoff based analyses. However, these have several simplifying assumptions which are important in design flood estimation. A continuous simulation approach to design flood estimation has many advantages and overcomes many of the limitations of the design event approach. A major concern with continuous simulation using a hydrological model is the scale at which should take place. According to Martina (2004) the “level” of representation that will preserve the “physical chain” of the hydrological processes, both in terms of scale of representation and level of description of the physical parameters for the modelling process, is a critical question to be addressed. The objectives of this study were to review the literature on different approaches commonly used in South Africa and internationally for design flood estimation and, based on the literature, assess the potential for the use of a continuous simulation approach to design flood estimation. Objectives of both case studies undertaken in this research were to determine the optimum levels of catchment discretisation, optimum levels of soil and land cover information required and, to assess the optimum use of daily rainfall stations for the configuration of the ACRU agrohydrological model when used as a continuous simulation model for design flood estimation. The last objective was to compare design flood estimates from flows simulated by the ACRU model with design flood estimates obtained from observed data. Results obtained for selected quaternary catchments in the Thukela Catchment and Lions River catchment indicated that modelling at the level of hydrological response units (HRU’s), using area weighted soils information and more than one driver rainfall station where possible, produced the most realistic results when comparing observed and simulated streamflows. Design flood estimates from simulated flows compared reasonably well with design flood estimates obtained from observed data only for QC59 and QCU20B. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

South Africa has a long history of problems with invasive alien species. In an assessment of alien invading plants and water resources in South Africa Versveld et al. (1998) estimated that Invasive Alien Plants (IAPs) in South Africa covered an area equivalent to the size of KwaZulu-Natal. However this area of invasion was primarily concentrated along the river courses of South Africa as alien invasions are arguably a riparian problem (Versveld et al., 1998). In a 1998 assessment of the distribution of IAPs in South Africa Versveld et al. (1998) found a total invasion extent of 8% for South Africa (including Lesotho), while KwaZulu-Natal had a higher total extent of invasion at 9.75%. However the authors noted the limitations of the IAP mapping assessment and stated that from personal observations and observers’ comments the area invaded by IAPs may be as much as 2-3 times greater than the 9.75% value obtained for KwaZulu-Natal. South Africa’s most widespread invasive alien tree (Dye and Jarmain, 2004), Acacia mearnsii (black wattle), is ubiquitous throughout KwaZulu-Natal, and invades most severely where water is plentiful, such as along watercourses and road verges. However following dispersal along rivers, A. mearnsii spreads into adjacent terrestrial habitats (Richardson and Kluge, 2008) including indigenous grassland and forest. A. mearnsii was introduced to South Africa in the middle 19th century to provide tanbark, woodchips, construction poles and firewood, and its introduction spread rapidly across KwaZulu-Natal through farmers and foresters (Henderson, 2001; WESSA, 2008). River and riparian zone rehabilitation is becoming accepted as having an essential role to play in the long term solution of water resource quality and supply problems and environmental health as a whole. As a result the impact of IAP invasions on water resources, ecological habitats and the delivery of ecosystem goods and services has undergone much scientific investigation (van Wilgen et al., 2008). Numerous studies have shown that, under most circumstances, removal of IAPs results in a general increase in streamflow and returns a stream to a more natural seasonal flow regime. However, scientific studies on the influences of woody IAPs on the hydrogeomorphology of riparian areas, and the resultant effects on stream hydrology and ecology, have undergone little scientific investigation in the South African context. Hydrogeomorphology studies the linkages of surface and subsurface water, and hydrological processes with landforms and geomorphic processes in temporal and spatial dimensions. As a result the discipline is well applied to the study of the interaction of, and interdisciplinary impacts of IAPs on riparian areas. Macdonald (2004:22) stated that there is a need to “investigate the interaction of IAPs with other aspects of water quality, for example soil erosion rates, including river channel and bank erosion.” In the early 1990s, after a study assessing the potential impact of IAPs on the geomorphology of river channels in South Africa, Rowntree (1991) stressed that further research on the influence of IAPs on stream geomorphology is required to guide truly effective riparian zone management. Since this study, little scientific work has been undertaken on this topic in the South African context. The literature review portion of this dissertation reviews the findings of various researchers as to how IAPs physically influence riparian habitats, specifically with reference to the role of IAPs in degrading riparian and streambank landscapes to an extent that streambank stability and stream channel form is adversely affected. This topic is introduced by illustrating the many functions that riparian zones can perform and some of the possible consequences of a loss of riparian habitat integrity. Worldwide awareness of the functions and values of riparian systems has led many countries to perform inventories of threatened and valuable riparian areas. A database of stream habitat integrity is useful for environmental impact assessments, development planning and resource inventories. Thus a multitude of stream survey and aquatic health sampling techniques and methodologies have been developed, some of which could be applied to assessing the influence of IAPs on riparian zones. 1.1 Research Aims and Objectives This dissertation forms a research study based on field research centred around field methods and tools developed after a review of relevant literature. The key aims of this research study are to; · refine an international river habitat survey method for application within South Africa, and · develop a test case to implement the developed method in analysing the impacts of IAPs on stream hydrogeomorphology in small headwater streams of KwaZulu-Natal, South Africa. These aims are achieved through the following objectives; · investigate the current body of knowledge covering the impact of woody IAP invasions on streambank stability and channel form, · review available stream survey methods and develop a stream survey methodology which can be applied to investigate the relationships between woody IAP invasions and streambank stability and form within headwater streams of KwaZulu-Natal, · investigate the relationships illustrated by the data after applying the developed stream survey tools and fieldwork methodology, and · discuss any shortfalls of the developed tools and methods, and suggest future needs. The hypothesis of the study contends that, within the focus of this study, invasion of headwater streams by woody IAPs can result in; · increased channel incision and bank steepening, and · an increase in streambank instability. 1.2 Document Structure Chapters 2 to 4 form a review of current literature to establish a base of understanding of the implications, processes and components involved in the invasion of riparian zones by Invasive Alien Plants. In Chapter 5 the approaches to stream surveying are assessed and selected methods of stream survey seen as applicable to this study are reviewed. Based on these findings, a method of stream survey for application in this study is developed and described in Chapter 6 following a description of the fieldwork sites and methodology. Chapter 7 provides an extensive analysis and exploration of the results of the various components of the fieldwork, which are then discussed in Chapter 8. Chapter 9 outlines final conclusions, analysis of the applicability of the findings, and suggestions with regards to future research needs. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Global climate change is a naturally occurring phenomenon, influencing weather and climate patterns. However, the greatest cause for concern at present is the rate at which climate change is currently occurring. Natural shifts in climate take place over a period of many thousands of years, not in a matter of decades, which is what is occurring at present. In South Africa, climate change is projected to have different regional effects, which in turn could impact on the components of the terrestrial hydrological system, such as land use. The alteration of the catchment upstream of the estuaries could affect the quantity and quality of streamflows entering estuaries. This could impact negatively upon estuaries, thereby reducing the considerable biodiversity in estuaries and the ecosystems goods and services provided by estuaries which would reduce the significant revenue provided by these systems. The research undertaken in this project investigates the possible effects of climate change, and changes in upstream land use on freshwater inflows into estuarine ecosystems using a daily hydrological model. Owing to the regionality of climate change in South Africa 10 estuaries in different climatic regions were selected for this investigation. Climate output from five GCMs under the SRES A2 climate scenario for the present (1971 – 1990), intermediate (2046 – 2065) and distant future (2081 – 2100) periods was used as input for the selected climate input. Results of these simulations show that the eastern regions of South Africa may experience considerable increases in the occurrence of high intensity rainfall events into the future. This could influence the abiotic factors of the system which may impact upon the biotic components of estuaries, as these systems are physically controlled. In the western regions the difference of the magnitude of flows between present and projected future is minimal. However, projected increases in temperature could influence evaporation, thereby decreasing future flows into estuaries. This, in some instances, may result in systems turning hyper-saline, which could have far reaching implications, both ecologically and economically. Additionally, an investigation, as to the possible effects of irrigation and climate change combined on flows entering and breaching events of the Klein estuary, was undertaken. Hence, simulations including and excluding irrigation routines have been completed. Results from these simulations illustrate the detrimental effects of irrigation into the future periods, especially during 1 in 10 low flow years, when flows into the Klein estuary cease completely. Breaching event results illustrate that climate change could have a negative impact on this estuarine system as the number of events decreases into distant future period. The addition of agricultural abstractions decreases the number of breaching events markedly. Therefore, the link between the marine and terrestrial hydrological systems is lost which could, if this estuary is isolated from the ocean for an extended period of time, become extremely detrimental to the ecological integrity of the Klein estuary. This highlights the value and vulnerabilities of estuarine ecosystems in South Africa to future climate and upstream land use changes. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

This thesis presents a comprehensive system analysis of the utilization of biowaste and forest industry residues to produce transportation fuels. It explores various aspects such as the constraints to the production system’s value chain development, the utilization of the geographical proximity of biofuel technology innovation system components, environmental impacts, and economic costs. The primary goal is to establish a knowledge base that can aid regional policymakers and decision-makers in formulating informed policies for the efficient management of local bioresources for transport fuel production. By addressing these aspects, the study seeks to contribute to the wider discourse on efficient local bioresource management and transition to a low-carbon economy. The focused bioresources in this thesis are municipal biowaste and forest industry residues (i.e., sawdust, black liquor, crude tall oil, and fiber waste of the pulp and paper industry). The study focuses on three systems: i) biowaste to biogas for transport, ii) biowaste and sawdust to hydrogen, and iii) forest industry residues to liquid biofuels for transport. The biofuel policy instruments in Sweden have proven to be effective in introducing alternative transport fuels, particularly in big cities or urban areas. The results of the biowaste to biogas value chain analysis show that development in the Gävleborg region is stagnated throughout the value chain compared to the national average. This stagnation is mainly attributed to local geodemographic factors. The identified obstacles to development include a lack of regional political agreement regarding the use of biogas as a viable transport fuel, insufficient connectivity and communication among the various regional actors and stakeholders, and a limited understanding among stakeholders of the potential and socio-economic impacts of biogas.  The environmental and economic assessment of hydrogen production from biowaste and sawdust is performed from a life cycle perspective, using SimaPro LCA software and CML-IA, 2001 impact assessment method. Economic analysis includes capital and operational expenditures and monetization cost of life cycle environmental impacts. The results show that hydrogen production from biowaste has a higher global warming, photochemical oxidant, and freshwater eutrophication potential than sawdust. Biowaste conversion to hydrogen performs far better in ozone depletion, terrestrial ecotoxicity, abiotic depletion-fossil, abiotic depletion, human toxicity, and freshwater ecotoxicity potential. The fossil energy inputs in biogas and pyrolysis oil reforming, emissions from the digestate treatment, storage, and utilization as bio-fertilizer are the main contributing processes to the overall environmental impacts of biowaste and sawdust conversion to hydrogen.  The sensitivity analysis of the LCA results indicates that feedstock to biogas/pyrolysis oil yield ratio and the type of energy source for the reforming process can significantly influence the results, particularly climate change, abiotic depletion, and human toxicity.  The life cycle cost (LCC) analysis reveals that the production of hydrogen from biowaste exhibits a lower cost compared to sawdust. This significant cost reduction in the biowaste case can be attributed to lower variable operating expenses (OPEX), primarily due to the price of the biowaste itself. Whereas, in the sawdust case, the feedstock contributes the highest percentage (54%) to the system's OPEX, indicating that variable OPEX is highly sensitive to sawdust prices. Additionally, the capital investment required for the biowaste case was 50% lower, which further contributes to the lower overall LCC compared to the sawdust case. The results of forest industry residues to liquid biofuel technology development and the utilization of system components in geographical proximity indicate that geographical proximity can significantly influence the system’s structural growth, trajectory, and development pace. An adapted version of the technological innovation system (TIS) framework was operationalized with the lens of geographical proximity utilization of the system components to the technology development and diffusion. The method of data acquisition involved document analysis and interviews with subsystem actors. The study found that the development of the system is hampered by competition between technologies and low utilization of geographical proximity of the system components, which was partly attributed to a lack of network among subsystem actors and with the national TIS structure.  Bioresources in Gävleborg are present in substantial amounts, particularly biowaste from agriculture, the food industry, and households, as well as biomass from the forest industry, which have the potential to be utilized for transport fuel production. However, the evolution of their utilization to power transportation in Gävleborg has been delayed in comparison to several other regions in Sweden. In the case of the technology development of forest industry residue-based transport fuels, the utilization of geographical proximity of artefacts and institutions has played a crucial role. Significant strides have been accomplished in diverse technology domains. However, these advancements have faced obstacles, partially due to the rivalry among system actors aiming to secure a competitive edge in acquiring both knowledge and capital resources and the underutilization of the geographical proximity of actors and industry networks.  Based on these research findings, recommendations are provided to support policy and strategy aiming to enhance the utilization of local bioresources for transportation fuels sustainably and cost-effectively with increased local benefits. For example, the study recommends addressing the identified local political, communication, and networking issues, along with integrating regional geodemographic conditions into national biofuel policies and measures. By addressing identified challenges, the Gävleborg region can overcome the stagnation in bioresource to transportation fuel technological systems development and leverage its significant potential. This thesis adds valuable insights to the sustainability transition literature about the environment, economy, and the geography of innovation processes. The findings highlight the need for policy interventions to foster collaboration, coordination, and knowledge sharing among stakeholders, as well as support for the development and commercialization of emerging technologies, including forest-based transport fuel technologies. The analysis of cost and environmental impacts of bioresource utilization for hydrogen production provides insights into the potential trade-offs and benefits of different feedstocks and impact categories. The study provides important input for policy and strategy development towards a more sustainable and cost-effective use of local bioresources for transport fuel production in Gävleborg. This study can also serve as a valuable reference for researchers, policymakers, and stakeholders interested in the sustainable utilization of renewable resources for biofuel production, contributing to the advancement of knowledge in this critical area. / Denna avhandling presenterar en omfattande systemanalys av utnyttjandet av bioavfall och skogsindustriella restprodukter för att producera drivmedel. Den utforskar olika aspekter såsom begränsningarna för produktionssystemens värdekedjeutveckling, utnyttjandet av den geografiska närheten till biobränsleteknik, innovationssystemkomponenter, miljöpåverkan och ekonomiska kostnader. Det primära målet är att etablera en kunskapsbas som kan hjälpa regionala beslutsfattare att formulera välgrundade policyer för effektiv förvaltning av lokala bioresurser för drivmedelsproduktion. Genom att ta itu med dessa aspekter försöker studien bidra till den bredare diskursen om effektiv lokal bioresursförvaltning och övergång till en koldioxidsnål ekonomi. De studerade bioresurserna i denna avhandling är kommunalt bioavfall och skogsindustrins restprodukter (d.v.s. sågspån, svartlut, råtallolja och fiberavfall från massa- och pappersindustrin). Studien fokuserar på tre system: i) Bioavfall till biogas för transport, ii) Bioavfall och sågspån till vätgas, och iii) Skogsindustrins restprodukter till flytande biobränslen för transporter. De politiska styrmedlen för biodrivmedel i Sverige har visat sig vara effektiva för att införa alternativa drivmedel, särskilt i storstäder eller tätorter. Resultaten av värdekedjeanalysen från bioavfall till biogas visar att utvecklingen i Gävleborgsregionen stagnerat i hela värdekedjan jämfört med riksgenomsnittet. Denna stagnation tillskrivs främst lokala geodemografiska faktorer. De identifierade lokala faktorer som hämmar utvecklingen är brist på regional politisk samsyn om biogas som drivmedel, bristande nätverk och kommunikation mellan regionala aktörer och intressenter samt otillräcklig kunskap hos intressenterna om biogaspotentialen och dess socioekonomiska konsekvenser. Den miljömässiga och ekonomiska bedömningen av vätgasproduktion från bioavfall och sågspån utförs ur ett livscykelperspektiv med hjälp av SimaPro LCA-programvara och CML-IA, 2001 konsekvensbedömningsmetod. Den ekonomiska analysen inkluderar kapital- och driftsutgifter och intäktsgenerering, samt kostnad för miljöpåverkan under livscykeln. Resultaten visar att vätgasproduktion från bioavfall har högre potentiellt bidrag till global uppvärmning, bildning av fotokemiska oxidanter och sötvattenövergödning än sågspån. Medan omvandling av bioavfall till väte presterar mycket bättre vad gäller potential för ozonnedbrytning, terrestrisk ekotoxicitet, abiotisk utarmning - fossil, abiotisk utarmning, mänsklig toxicitet och sötvattenekotoxicitet. Fossil energitillförsel i biogas och pyrolysoljereformering, utsläpp från rötrestbehandling, lagring och användning som biogödsel är de viktigaste bidragande processerna till den totala miljöpåverkan från omvandling av bioavfall och sågspån till väte. Känslighetsanalysen av LCA-resultaten indikerar att förhållandet mellan råmaterial och biogas/pyrolys-olja och typen av energikälla för reformeringsprocessen kan påverka resultaten avsevärt, särskilt potential för klimatförändringar, abiotisk utarmning och mänsklig toxicitet.   Livscykelkostnadsanalysen (LCC) visar att produktionen av vätgas från bioavfall ger en lägre kostnad jämfört med sågspån. Denna betydande kostnadsminskning för bioavfall kan hänföras till lägre rörliga driftskostnader (OPEX), främst på grund av priset på själva bioavfallet. När det gäller sågspån bidrar råvaran med den högsta andelen (54 %) till systemets OPEX, vilket indikerar att variabeln OPEX är mycket känslig för sågspånspriser. Dessutom var kapitalinvesteringen som krävdes för bioavfallet 50% lägre, vilket ytterligare bidrar till den lägre totala livscykelkostnaden jämfört med sågspånsfallet. Resultaten från studien av skogsindustrins rester till flytande drivmedels teknikutveckling och utnyttjande av geografisk närhet mellan systemkomponenterna indikerar att de geografiska närhetväsentligt kan påverka systemets strukturella tillväxt, utvecklingsbana och -takt. En anpassad version av ramverket för teknologiska innovationssystem (TIS) operationaliserades med fokus på utnyttjande av geografisk närhet mellan systemkomponenter för teknikutveckling och spridning. Metoden för datainsamling involverade dokumentanalys och intervjuer med delsystemaktörer. Studien fann att utvecklingen av systemet hämmas av konkurrens mellan tekniker och lågt utnyttjande av geografisk närhet mellan systemkomponenter, vilket delvis berodde på bristandenätverk bland delsystemaktörer och den nationella TIS-strukturen.  Bioresurser i Gävleborg finns i betydande mängder, särskilt bioavfall från jordbruks- och livsmedelsindustrin och från hushållen, samt biomassa från skogsindustrin, som har potential att utnyttjas för drivmedelsproduktion. Utvecklingen av deras användning för att driva transporter i Gävleborg har dock försenats jämfört med flera andra regioner i Sverige. När det gäller teknikutvecklingen för drivmedel från skogsindustrins restprodukter har utnyttjandet av geografisk närhet mellan artefakter och institutioner spelat en avgörande roll. Framstegen har dock delvis hindrats av rivalitet mellan tekniker och underutnyttjande av aktörernas och branschnätverkens geografiska närhet.   Baserat på dessa forskningsresultat ges rekommendationer för att stödja politik och strategier som syftar till att öka utnyttjandet av lokala bioresurser för transportbränslen på ett hållbart och kostnadseffektivt sätt med ökad lokal nytta. Studien rekommenderar till exempel att man tar itu med de identifierade lokala politiska, kommunikations- och nätverksfrågorna, och samtidigt verkar för att integrera de regionala geodemografiska förhållandena i den nationella biobränslepolitiken. Genom att adressera identifierade utmaningar kan Gävleborgsregionen övervinna stagnationen i utvecklingen av tekniska system för bioresurser till drivmedel och utnyttja dess betydande potential. Denna avhandling tillför värdefulla insikter till litteraturen om hållbar omställning om miljö, ekonomi och innovationsprocessers geografi. Resultaten belyser behovet av politiska insatser för att främja samarbete, samordning och kunskapsdelning mellan intressenter, samt stöd för utveckling och kommersialisering av ny teknik, inklusive skogsbaserad drivmedelsteknik. Analysen av kostnader och miljöpåverkan för bioresursutnyttjande för vätgasproduktion ger insikter i de potentiella avvägningarna och fördelarna för olika råvaror och påverkanskategorier. Studien ger viktig input för policy- och strategiutveckling mot en mer hållbar och kostnadseffektiv användning av lokala bioresurser för drivmedelsproduktion i Gävleborg. Denna studie kan också utgöra en värdefull referens för forskare, beslutsfattare och intressenter som är intresserade av hållbart utnyttjande av förnybara resurser för biobränsleproduktion, vilket bidrar till kunskapsutvecklingen inom detta kritiska område.