The South African sugar industry is of significant local and international importance and covers an area in excess of 450 000 hectares. This area yields approximately 21 million tons of sugarcane per annum which is transported almost exclusively by road, from farms to the sugar mills. The industry is under increasing economic pressures to improve its productivity and competitiveness and sugarcane transport in the sugarcane supply chain has been identified as one area where large improvements and associated cost reductions can be made. This is mainly due to the excess in number of vehicles in the inbound transport system, the high relative cost of transport compared to other production costs in producing sugarcane, and the high fixed costs associated with truck fleet operations. A simulation case study of the transport system was completed in 2005 in the Sezela Mill area in which approximately 2.2 million tons of sugarcane is transported per annum over an average distance of 29 km by approximately 120 independently managed vehicles owned by a wide range of hauliers and individual growers. This amounts to an estimated cost of R58 million per annum. This study investigated the potential savings that could occur as a result of a central fleet control system with integrated vehicle scheduling. A scheduling software package named ASICAM, which resulted in significant savings in the timber industry (Weintraub et al, 1996), was applied within the Sezela region. Results suggested that the number of trucks in the fleet could theoretically be reduced by at least 50%, providing that a central office controls vehicle movements and that all hauliers serve all growers in an equitable fashion. In addition, investigations towards decreasing loading times, decreasing offloading times, changing vehicle speeds and increasing payloads by reducing trailer tare mass showed further reductions in the number of trucks required. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

The budgeting of water fluxes in the soil is an extremely complex problem, and is compounded by subsurface controls and environmental forces which modify the soil water dynamics. Of the controlling factors, the underlying geology and the soil media are vital components and are often misinterpreted. The geology and soil media components have been neglected mostly because of the difficulty in monitoring the dominant processes that are linked to the water balance in the subsurface. Until recently, hydrometry has been the dominant method of measuring and monitoring the subsurface water balance. Hydrometric measurements have included water content measurement by Time Domain Reflectometry (TDR), soil water potential measurements through tensiometry and groundwater water level monitoring. Hydrometry is still the preferred method of monitoring soil water dynamics, but measurements are generally localised and lateral accumulations and fluxes of water are difficult to interpret. Using geophysical methods and instrumentation to define soil water dynamics could have numerous advantages over conventional hydrometric methods. Among the geophysical techniques dedicated to image the near surface, Electrical Resistivity Tomography (ERT) surveying has been increasingly used for environmental, engineering and geological purposes during the last decade. The aim of this study is to determine if ERT observations could yield the accuracy required to define vertical and lateral soil water dynamics. The ERT instrumentation uses an electrical current that is inserted into the subsurface through various electrode arrangements and a resulting resistance is determined at the take-out electrodes. With the aid of a modelling package these resistance values are reproduced into a pseudosection of underlying resistivity distribution which is influenced by the moisture conditions of the subsurface medium. This geophysical method is primarily used for geological studies but by doing repeated surveys with the same electrode positioning, moisture fluctuation monitoring could be realised. Use of the ERT technique is at the forefront of soil water dynamics monitoring. The main objective of this study is to propose that the ERT instrumentation could be a more efficient and more informative method of studying soil water dynamics than the traditional soil water dynamics monitoring equipment, particularly to define lateral fluxes and accumulation of subsurface water. The study site is a well instrumented transect in the Nkuhlu Exclosures in the Kruger National Park, South Africa, where ongoing soil water dynamics are monitored. The project aims to compare the ERT data to fiR data on a daily basis, over a period of three weeks, during the rain season, monitoring event based wetting and the subsequent drying phases of the soils in a 2-dimensional section. The project and its fmdings are shown to be valuable to the hydrological interpretation of the subsurface water balance. The application is shown to be particularly important to ecohydrology, in the monitoring of soil water dynamics in a 2-dimensional transect and understanding how the natural cycles of water distribution and plant uptake are linked together. The study demonstrates that ERT can be used to observe changes in the water storage and lateral fluxes within a transect which supports varying vegetation and ecologies. The linking of water fluxes in the hydrology cycle to uptakes and controls in the ecosystem has been developed into the research focus known as ecohydrology The use of the ERT instrument can only benefit this research focus in the future. The study demonstrates that ERT instrumentation can be used to provide valuable understanding of subsurface water dynamics and in turn the effects on ecohydrology. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

The change in total evaporation through alteration of vegetative cover is a major influence on catchment hydrology. The transformation of grassland and scrub habitats to commercial tree plantations, as well as the uncontrolled spread of invasive alien plants (lAPs) to ecologically sensitive systems, riparian zones in particular, are a threat to biodiversity and integrity of natural systems. Furthermore, critical low flow periods are of particular concern to water managers and local communities, as well as the associated impacts of potentially compromised water resources for rural livelihoods. The Working for Water (WfW) programme was implemented in 1995 by the Department of Water Affairs and Forestry and its main goals are to remove lAPs in order to improve water supply while at the same time providing employment to marginalised communities. In this study, the hydrological response to lAPs in the Upper Blyde River catchment is assessed. This is done by developing a classification structure for lAPs as a land use using detailed mapping available from WfW for use in a hydrological model, and then configuring and running the ACRU hydrological model for the Upper Blyde River catchment in Mpumalanga. In the classification, lAPs are represented as spatially explicit land use units in the ACRU model according to the type of habitat they invade, viz. riparian or non-riparian; as well as by type of plant, i.e. tree or shrub; and their area and density. The results obtained from simulating catchment hydrological responses using the ACRU model indicate that riparian lAPs have a great er impact on streamflow than do landscape invasions alone, specifically during periods of low flow. An increase in streamflow after removing lAPs from riparian and non-riparian habitats is a consistent outcome at both subcatchment and catchment scales. Using a spatially explicit method in order to model the hydrological response of different types of lAPs for different density classes in both riparian and non-riparian habitats is found to be a useful technique in determining the degree to which lAPs influence catchment streamflow. Recommendations for future research include focussing hydrological assessments of lAPs on critical flow periods and their impacts on water quality; investigation into the water use of invasive and indigenous vegetation for more accurate estimates from modelling exercises; and finally, applying the classification system for lAPs with other land use sensitive hydrological models for validation, and their wider application by incorporating methodologies into guidelines for use by WfW at national and provincial level. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

In many of the rural areas of South Africa local communities rely on wetland resources for daily living. For a symbiotic relationship to exist between these communities and the wetlands, the wetlands must be utilised in a manner sustainable to both parties. To prevent exploitation thereof, a comprehensive understanding of the processes and functions of wetlands, of the values and needs of rural community members, and of the interactions between these entities is essential. This study focuses on research at three scales; the plot scale (10m\ the microcatchment scale (lkm2 ), represented by the Craigiebum wetland and microcatchment, and the catchment area upstream of the gauging weir X3H008, all of which exist in the Sand River catchment in the Mpumalanga and Limpopo Provinces of South Africa. Relationships between the geomorphological properties of the Craigiebum microcatchment, the wetland management practices of the local communities, and the hydrological properties of the microcatchment have been investigated. Various hydrological models, but in the main the ACRU model, have been adopted as tools to facilitate this research. Possible scenarios of changes in land use, rainfall and soil texture were performed at the plot scale and at the scale of the microcatchment, and changes in wetland extent were simulated and analysed at the scale of the catchment. Results of the modelling exercises simulating the effects of differences in soil texture higWight the positive effects of retention of fine particles within a wetland in a sandy environment. These results also depict greater rates of hydraulic conductivity, erosion and desiccation within coarse-textured soils than fmer textured soils. Low levels of fertility can also be attributed to the lack of fine particles present in the soils of the Craigiebum microcatchment wetland. Results of the modelling exercises that investigate the likely hydrological effects of a variety of land uses within the Craigiebum microcatchment verify accepted hydrological theory, as they highlight that more impervious areas produce more stormflow and lose more water to evaporation, and that the natural vegetation of the area contributes to streamflow regulation more than other land uses do. The exercises performed at the scale of the Sand River catchment do not provide conclusive evidence of the effects of changes in wetland extent, as the hydrological effects that other land uses in the area have appear to override the effects of the simulated wetland areas. Analysis of the sociological data captured highlights the great extent to which the local community depends on the Craigieburn wetland resources for a variety of livelihood strategies. Furthermore it illustrates the degree to which a reduction in wetland health negatively impacts upon the community. Viewed in conjunction, the hydrological, biophysical and sociological results highlight the degree to which changes in one aspect of the environment affect other aspects thereof, thereby highlighting the degree to which these aspects of the Craigieburn microcatchment are inextricably linked. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

South Africa experiences some of the lowest water resource system yields in the world as a result of the high regional variability of rainfall and runoff. Population growth and economic development are placing increasing demands on the nation's scarce water resources. These factors, combined with some of the objectives of the new National Water Act (1998), are highlighting the need for efficient management of South Africa's water resources. In South Africa's National Water Act (1998) it is stated that its purpose is to ensure that the nation's water resources are protected, used, conserved, managed and controlled in a way, which takes into account, inter alia, i. promoting the efficient, sustainable and beneficial use of water in the public interest, and ii. managing floods and droughts. Efficient and sustainable water resource and risk management can be aided by the application of runoff forecasting. Forecasting thus fits into the ambit of the National Water Act and, therefore, there is a need for its operational application to be investigated. In this document an attempt is made to test the following hypotheses: Hypothesis 1: Reliable and skilful hydrological forecasts have the ability to prevent loss of life, spare considerable hardship and save affected industries and commerce millions of Rands annually if applied operationally within the context of water resources and risk management. Hypothesis 2: Long to medium term rainfall forecasts can be made with a degree of confidence, and these rainfall forecasts can be converted into runoff forecasts which, when applied within the framework of water resources and risk management, are more useful to water resource managers and users than rainfall forecasts by themselves. The validity of Hypothesis 1 is investigated by means of a literature review. South Africa's high climate variability and associated high levels of uncertainty as well as its current and future water resources situation are reviewed in order to highlight the importance of runoff forecasting in South Africa. Hypothesis 1 is further examined by reviewing the concepts of hazards and risk with a focus on the role of effective risk management in preventing human, financial and infrastructural losses. A runoff forecasting technique using an indirect methodology, whereby rainfall forecasts are translated into runoff forecasts, was developed in order to test Hypothesis 2. The techniques developed are applied using probabilistic regional rainfall forecasts supplied by the South African Weather Service for 30 day periods and categorical regional forecasts for one, three and four month periods for I regions making up the study area of South Africa, Lesotho and Swaziland. These forecasts where downscaled spatially for application to the 1946 Quaternary Catchments making up the study area and temporally to give daily rainfall forecast values. Different runoff forecasting time spans produced varying levels of forecast accuracy and skill, with the three month forecasts producing the worst results, followed by the four month forecasts. The 30 day and one month forecasts for the most part produced better results than the more extended forecast periods. In the study it was found that hydrological forecast accuracy results seem to be inversely correlated to the amount of rainfall received in a region, i.e. the wetter the region the less accurate the runoff forecasts. This trend is reflected in both temporal and spatial patterns where it would seem that variations in the antecedent moisture conditions in wetter areas and wetter periods contribute to the overall variability, rendering forecasts less accurate. In general, the runoff forecasts improve with corresponding improvements in the rainfall forecast accuracy. There are, however, runoff forecast periods and certain regions that produce poor runoff forecast results even with improved rainfall forecasts. This would suggest that even perfect rainfall forecasts still cannot capture all the local scale variability of persistence of wet and dry days as well as magnitudes of rainfall on individual days and the effect of catchment antecedent moisture conditions. More local scale rainfall forecasts are thus still needed in the South African region. In this particular study the methods used did not produce convincing results in terms of runoff forecast accuracy and skill scores. The poor performance can probably be attributed to the relatively unsophisticated nature of the downscaling and interpolative techniques used to produce daily rainfall forecasts at a Quaternary Catchment scale. It is the author's opinion that in the near future, with newly focussed research efforts, and building on what has been learned in this study, more reliable agrohydrological forecasts can be used within the framework of water resources and risk management, preventing loss of life, saving considerable hardship and saving affected industry and commerce millions of rands annually. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

Predictions that water shortages will constrain economic growth in South Africa by 2025 have led to increased concerns among water resource managers that there is a need for comprehensive water management strategies. To this extent the new South African Water Act requires that water resource allocation be approached in a more equitable and conservative way than in the past in order to sustain water resources for catchment development. This includes protection of the water resource base by the setting aside of a health Reserve for basic human needs and for the ecological functioning of rivers. At a time when water resource management is shifting from the practice of large dam construction to reconciling water demand with water supply in more holistic strategies, the Mkomazi Catchment in KwaZulu-Natal provides an opportunity to investigate some of the major issues that dominate contemporary water resource management. Presently (2001), there are no impoundments on the Mkomazi River and the catchment is generally underdeveloped. These factors have provided the impetus for the Department of Water Affairs and Forestry's proposed inter-basin transfer scheme to use the surplus flow in the Mkomazi Catchment to augment the water resources of the neighbouring Mgeni system. Impact-of-Iand-use and development scenario studies, using the ACRU agrohydrological modelling system, were performed to simulate the impacts of (a) baseline land cover, (b) present land use, (c) the first phase of the Mkomazi-Mgeni Transfer Scheme and (d) potential climate change on the hydrological dynamics of the Mkomazi Catchment. The results indicate that the change from baseline land cover conditions to present land use conditions has little impact on the annual water resources of the Mkomazi River. This is especially so in the upper catchment where there is little anthropogenic development and from where the planned inter-basin transfer will be made from the proposed Smithfield Dam. Although the impacts of commercial forestry and irrigation in the middle and lower catchment impose local stress on streamflow generation, they do not detract substantially from the main downstream flows. Evaluation of the impacts of the proposed Smithfield Dam on annual streamflow generation revealed that there is more than sufficient water in the upper Mkomazi Catchment to sustain the inter-basin transfer under present climatic conditions. However, under potential climate change the median annual Mkomazi streamflows at the estuary could be reduced by 46% if the dam was constructed, compared with a 22% reduction under present climatic conditions. The impacts of catchment development on the seasonal low flows within the Mkomazi Catchment indicated that those areas which are already heavily utilised by afforestation and, particularly, by irrigated land use are unlikely to be able to support any further large scale commercial agricultural development, even under present climatic conditions. Water management strategies for the Mgeni system will impact on potential water allocation within the Mkomazi Catchment. The results of the impacts studies were used to assess the water demand of the major water-use sectors and the availability of streamflows for further allocation was assessed. Present total annual water demands of Mkomazi streamflows is minimal. Even allowing for the environmental demand in the Mkomazi Catchment, as identified by the Building Block Methodology during an instream flow requirements workshop, as well as the first phase of the inter-basin transfer, there would be surpluses of 66%, 43%, 42% and 45% of streamflows, respectively, at the four instream flow requirement sites on the Mkomazi River. The results of the Mkomazi instream flow requirements workshop were revisited to assess the achievability of the recommended flows within the ACRU generated daily time series of streamflows for each of the scenarios simulated, at the each of the four instream flow requirement sites on the Mkomazi River. The results confirmed the need to ascertain the Mkomazi River's natural flow variability, and to assess how much alteration is likely under development of the Mkomazi Catchment. The Indicators of Hydrologic Alteration and Range of Variability Approach methodologies were used to determine which components of the streamflow regime would be most impacted by the inter-basin transfer. Hypothetical, yet realistic, upper and lower management target thresholds were applied to determine the range of variation experienced by the streamflow regime of the Mkomazi, under both pre- and post-dam construction conditions, and to evaluate a preliminary assessment of the characteristics of the streamflow regime required to meet environmental sustainability. The issues raised by potentially conflicting water uses within catchments in South Africa have indicated that any approach to address the increasing complexity of water resource problems, and the management thereof, requires effective hydrological modelling. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Resource managers frequently require moderate to high resolution imagery within short turnaround periods for use in a GIS-based management system. These spatial data can greatly enhance their ability to make timely, cost-saving decisions and recommendations. MBB Consulting Engineers, Inc., of Pietermaritzburg, South Africa had for many years made use of airborne videography to provide the imagery for several resource-based applications. Applications included detailed land use mapping in various South African river catchments and identification, density classification and mapping of alien vegetation. While the system was low cost and easy to operate, MBB had found that their system was inherently limited, particularly by its lack of automation and poor spatial resolution. This project was started because of a need to address these limitations and provide an airborne remote sensing system that was more automated and could produce higher resolution imagery than the existing system. In addition, the overall cost and time required to produce a map of the resource of interest needed to be reduced. The system developed in this project aimed to improve upon the pre-flight planning and in-flight image acquisition aspects of the existing system. No new post-flight image processing procedures were developed, but possible future refinement of the post-flight image processing routine was considered throughout the development of the system. A pre-flight planning software package was developed that could quickly and efficiently calculate the positions offlight lines and photographs or images with a minimum of user input. The in-flight image acquisition setup developed involved the integration of a high resolution digital still camera, a Global Positioning System (GPS), and camera control software. The use of the rapidly developing and improving technology of a digital still camera was considered to be a better alternative than a video graphic or traditional film camera system for a number of reasons. In particular, digital still cameras produce digital imagery without the need for development and scanning of aerial photographs or frame grabbing of video images. Furthermore, the resolution of current digital still cameras is already significantly better than that of video cameras and is rivalling the resolution of 35rnm film. The system developed was tested by capturing imagery of an urban test area. The images obtained were then rectified using photogrammetric techniques. Results obtained were promising with planimetric accuracies of 5 to 1 Om being obtained. From this test it was concluded that for high accuracy applications involving numerous images, use would be made of softcopy photogrammetric software to semi-automatically position and rectify images, while for applications requiring fewer images and lower accuracy, images could be rectified using the simpler technique of assigning GCPs for each image from scanned orthophotos. / Thesis (MSc.)- University of Natal,Pietermaritzburg, 2000.

Due to the significant cost of transport in the sugar industry, a model, named FastTrack, was developed to investigate infrastructure planning opportunities. The model mathematically incorporates road construction and maintenance costs, terrain and land-use maps, vehicle performance specifications and annual sugarcane volumes to determine the most cost effective route, per vehicle type, from a production region to a mill. Route planning using geographical information systems (GIS) is a standard approach for determining the optimum alignment for pipelines, roads and canals. Theory of this approach was reviewed to create a foundation for the development of FastTrack. A small portion of the Noodsberg sugar mill region in the KwaZulu-Natal midlands was selected as a case study area to test the capabilities of FastTrack. A start location was identified as a natural flow point for 70 000 tons of sugarcane hauled from an area south of the mill. Currently this volume is transported along a 9.3 km stretch of national road from the start location to the sugar mill, while the Euclidean distance is approximately 7 km. Three vehicle types, differing in payload, fuel consumption and road speed were assessed. Two common and currently utilised vehicles, the tractor hilo and interlink combinations, were aligned by FastTrack along existing national roads. A financial penalty for driving on national roads was assumed for the third vehicle type considered, land trains, as these are currently not permitted to operate on national roads in South Africa. This high bulk vehicle was selected to test the capabilities of FastTrack and to identify if cost savings could be realised through increased consignment capacity as has been achieved in Australia, Malawi and Brazil. Utilising the model a new and more direct theoretical route was generated for the land train with a length of 7.4 km. Existing farm roads which would require upgrading made up 34 % of this proposed route. An economic analysis was conducted and showed that under current conditions, the private route generated by FastTrack for land train use, would be the most cost effective, with a system cost of R 57.50 t" . The tractor hilo and interlink had system costs of R 59.58 t" and R 60.98 t"1 respectively. Repeating the economic analysis with projected fuel prices indentified that the cost saving advantage of the land train system over the other two vehicle configurations increases with increasing fuel costs. A rigorous validation process, including a sensitivity analysis of results from FastTrack, revealed that the model performs predictably under a wide range of input conditions and could be a valuable tool for decision making in the sugar industry. However, further research is required to combine more economic and logistical aspects into FastTrack and to increase its usability. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

South Africa lacks affordable irrigation technologies suited entirely to the needs of small-scale farmers. This is mainly due to the past emphasis on large, commercial farming technologies and the misunderstanding that emerging farmers can utilise scaled down versions of such technologies. It is now believed that increased irrigation amongst smallholders could largely assist with food security and poverty alleviation in South Africa. The object of this project was therefore to evaluate selected appropriate irrigation technologies that are currently being used in other developing countries with the intention of introducing them into South Africa. A literature review on all the irrigation technologies currently being used by small-scale farmers in South Africa was performed. The literature review provided information on the factors affecting the adoption of irrigation technologies. Selected technologies, namely, various low-cost, manual pumps and drip irrigation kits were then imported and evaluated under local conditions. The evaluation process was divided into two sections. Qualitative evaluations were carried out on farms and by farmers themselves and quantitative evaluations were carried out in laboratories and closely monitored field trials. A South African prototype pump was then designed and built following the knowledge gained from testing the imported pumps. The prototype was tested and then refined and rebuilt. The qualitative test results showed a very positive reaction from farmers towards the pumps. The drip irrigation kits were often not used as a result of a lack of understanding by the farmers. The laboratory test phase highlighted the more critical components of the pumps. A recommended introduction strategy was then developed and is presented. This evaluation process and introduction strategy could in future be used as a guideline when developing other suitable technologies for small-scale farmers.I wish to certify that the work reported in this dissertation is my own unaided work except where specific acknowledge is made. In addition I wish to declare that this dissertation has not been submitted for a degree in any other university. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

Dams hold numerous benefits for society through their ability to store water on a long-term basis. However, it is well-known that there is a detrimental effect of dams on the rivers that they impound, and this has been taken into account by the South African National Water Act (1998). The Act specifies a two component Reserve to provide a basic water supply to humans and to provide protection to downstream rivers and their associated ecosystems. From an ecological perspective, emphasis is now placed on ensuring that flow in rivers is maintained in a state that closely mimics the natural flow regime in order to sustain the water resource and its associated aquatic ecosystems. The resulting challenge for water resources modelling is to develop operating rule frameworks that can account for water supply to multiple users, including the "environment" which represents downstream aquatic ecosystems. These frameworks need to consider both water stored in dams, as well as water in the river which has been allocated to different water uscrs. Such an operating rule framework has been implemented ID the daily time-step ACRU agrohydrological model in order to: (a) satisfy the requirements of water users in general, (b) (c) include the environment as a user of water, and thus attempt to satisfy the water requirements of rivers and their associated ecosystems by making artificial releases from dams using both a simple and a complicated approach for determining the environmental requirements. The framework identifies four types of water users, each of which are capable of requesting water from a water source. These users are: a domestic user, representing the basic human needs component of the Reserve, an environmental user, representing the ecological component of the Reserve, an industrial user and an irrigator. The environmental user can generate water requests using either a simple or a complex environmental request method. The simple approach has proved to be oversimplified while the complex approach is capable of producing a flow regime downstream of a dam that closely mimics the natural flow regime. Two operating rules are employed to supply water to the four users, a generic dam operating rule, which considers water requested from a dam, and a channel operating rule, which considers water requested from a river. The two operating rules determine the amounts of water that each user can receive through the use of a curtailment structure, where abstractions made by users are limited, based on the storage level in the dam. Extensive validation of the framework has taken place and a case study was undertaken on the Pongola-Bivane river system which includes the Paris Dam in order to run various real-life scenarios. The results obtained show not only that the operating rule framework is functioning correctly, but that the use of a curtailment structure holds advantages for increasing assurance levels of the water users. There is also evidence to suggest that future possibilities exist for practical application of the operating rule framework to "everyday" dam operations. / Thesis (M.Sc.)-University of Natal,Pietermaritzburg, 2001.