Environmental Science

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An investigation into using GIS in electrification and network planning in rural KwaZulu-Natal.
(2006) Barnard, Jennifer B.; Ahmed, Fethi B.
The South African Government has set a target of universal access to basic electricity by the year 2012. Free basic electricity is defined as the amount of electricity sufficient to provide basic lighting, media access, water heating and ironing with on-grid electricity; or basic lighting and media access for a non-grid system. Eskom Distribution, in conjunction with local municipalities, is responsible for the outstanding electrification predominantly in rural areas. In KwaZulu-Natal, mountainous terrain and scattered settlement patterns of communities complicate the achievement of this goal. This study was aimed at using GIS to address the urgent need to plan electrification, firstly by identifying areas that need electrification and secondly by prioritising those areas according to set principles. Electrification areas were effectively identified and prioritised from both a need and capability of supply aspect. The study then aimed at designing the shortest networks from the grid to those identified electrification areas. To determine electrification areas spatially, electoral areas (EAs) demarcated as rural during the run up to the 1994 elections were used to identify rural areas; and Ethekwini Metropolitan Municipality, current electrification projects, reserves and a buffer zone around existing transformers excluded. Household point data was used to polygonize the remaining area, and those polygons were aggregated on their calculated area to create future rural electrification areas (FREA). A points and weighting system; based on one initially used in Namibia and further developed in an electrification planning model by RAPS Consulting, CSIR and DME to prioritise villages for electrification; was applied to calculate point scores for each FREA and other criteria such as distance from a network with capacity considered to determine a prioritised list of FREA that can be electrified immediately. Roads, land cover, household positions and slope were used to design the shortest path from the grid to the three highest scoring FREA. Each layer was reclassified, ratings applied and the layers combined to successfully determine the final path in terms of the criteria used. Interest in using GIS for spatial planning has led to a GIS Initiative Group (GISIG) being formed at Eskom Distribution in Eastern Region to address data collection, co-ordination of planning, tools written previously but never implemented being re-evaluated and, more recently, new tools being designed. However, much is still needed in terms of research, resolving of data quality issues, testing of points and weighting systems, and for functionally independent sections to work together on making changes to age-old system structures and processes before any of the recommendations resulting from this study can be effectively implemented.
The application of route network analysis to commercial forestry transportation in the north coast of Kwazulu-Natal.
(2005) Stewart, Lissa Anne.; Ahmed, Fethi B.; Watson, Helen Kerr.
Transportation costs of commercial forestry farms in South Africa are generally very high, causing great economic concern. The current roads of the majority of commercial farms, used to transport timber from the compartments to the market (mill), form part of a 'cob-web', high density network. In order to optimise transportation, it is beneficial to eradicate such a high density of road, achieved by adopting the most effective methods and technology. Such methods include that of Route Network Analysis (RNA) which designs a minimalist, yet cost-effective road pattern of a forestry farm. The aim of the study was to determine what data are required to optimise economic and timber transportation, based on the commercial forestry farm of Ntonjaneni, located in Zululand, KwaZulu-Natal. Route Network Analysis, which incorporates Geographical Information Systems (GIS) in addition to the current information pertaining to a network, was applied to the Ntonjaneni Farm. The existing data consisted of cadastral shapefile data containing relative attribute data, as well as Digital Elevation Models (DEMs), which were manipulated in order to create a realistic spatial representation of the farm's current transportation network. In addition, the development of project management guidelines to assist the efficient implementation and completion of the analysis was undertaken. The most ideal route from the plantations to the mill was created, avoiding the environmentally buffered rivers and those slopes which were too steep. As a result, the network was greatly improved. The irrelevant roads were removed, and replaced with a less dense route for timber transportation. The results of the RNA reveal that RNA, completed by the project management guidelines, is an effective and environmentally sound means of optimising commercial forestry transportation. However, data relating to the rivers and road slope need to be updated in order for RNA to be effectively performed during future studies.
An assessment of changes in land use/cover patterns in the Albert Falls area, KwaZulu-Natal, South Africa.
(2003) Yemane, Mehreteab Michael.; Ahmed, Fethi B.
The Albert Falls Area had witnessed severe competition over land use between agriculture, recreation, conservation and other land uses. The area also has been the scene for inefficient land management that led to degradation of land resources. For proper land use planning and environmental management, information on land use/cover change is vital. This study has developed a spatial and descriptive historical land use/cover databases for the years 1944, 1967, 1989, and 2000 to provide an understanding of land use/cover patterns in Albert Falls Area. The databases were created by interpreting historical aerial photographs and using Geographic Information Systems. The data was subsequently analyzed to detect relevant trends in land use/cover patterns in the study area. Generally land use/cover pattern of Albert Falls Area during the period 1944 to 2000 may be described as being mainly agricultural. The results showed a marginal increase of indigenous forests attributed to the continuous efforts by different governmental departments and policies that focused on the protection of the remaining patches of indigenous forests. Grassland not only decreased by more than half but it also deteriorated in quality during 1944 to 2000. Commercial Forestry predominates the study area and showed an increasing trend from 1944 to 1967. Cultivated Land was observed to decrease at the expense of Commercial Forestry plantations and Waterbodies. Although sugarcane plantations increased after 1967, total Cultivated Land showed a decreasing trend. The construction of Albert Falls Dam and other small Farm Ponds within the agricultural farms increased the land areas covered by Waterbodies. Residential Area coverage generally decreased irrespective of the encroachment of informal settlements, while that outside Non-Residential Area and Transportation Routes generally increased with the development of commercial agriculture in the area. Barren Land decreased continuously due to higher land demand in the study area. The study showed that land use/cover changes in Albert Falls Area. have resulted in habitat fragmentation, development of monoculture land use, flourishing of Farm Ponds in agricultural farms, and expansion of agricultural activities on marginal lands. Creation of corridors/linkages between the fragmented forest patches; commencement and implementation of the already well drafted land and land resource policies and regulations; commencement of the holistic management plans in the area were recommended for a sustainable land use.
An assessment of land cover changes using GIS and remote sensing : a case study of the uMhlathuze Municipality, KwaZulu-Natal, South Africa.
(2005) Robson, Thomas Forster.; Ahmed, Fethi B.; Hill, Trevor Raymond.
Rapid growth of cities is a global phenomenon exerting much pressure on land resources and causing associated environmental and social problems. Sustainability of land resources has become a central issue since the Earth Summit in Rio de Janeiro in 1992. A better understanding of the processes and patterns of land cover change will aid urban planners and decision makers in guiding more environmentally conscious development. The objective of this study was firstly, to determine the location and extent of land use and land cover changes in the uMhlathuze municipality, KwaZulu-Natal, South Africa between 1992 and 2002, and secondly, to predict the likely expansion of urban areas for the year 2012. The uMhlathuze municipality has experienced rapid urban growth since 1976 when the South African Ports and Railways Administration built a deep water harbour at Richards Bay, a town within the municipality. Three Landsat satellite images were obtained for the years, 1992, 1997 and 2002. These images were classified into six classes representing the dominant land covers in the area. A post classification change detection technique was used to determine the extent and location of the changes taking place during the study period. Following this, a GIS-based land cover change suitability model, GEOMOD2, was used to determine the likely distribution of urban land cover in the year 2012. The model was validated using the 2002 image. Sugarcane was found to expand by 129% between 1992 and 1997. Urban land covers increased by an average of 24%, while forestry and woodlands decreased by 29% between 1992 and 1997. Variation in rainfall on the study years and diversity in sugarcane growth states had an impact on the classification accuracy. Overall accuracy in the study was 74% and the techniques gave a good indication of the location and extent of changes taking place in the study site, and show much promise in becoming a useful tool for regional planners and policy makers.
The cumulative effect of wetland degradation on water quality at a landscape scale.
(2009) Jaganath, Charissa.; Ellery, William Nolan.; Ahmed, Fethi B.; Kotze, Donovan Charles.
Wetlands have been described as “one of the most globally threatened and important ecosystems”, with most wetlands providing a variety of important ecosystem services, including water quality enhancement. Despite their importance the loss of wetlands is more rapid than that of any other ecosystem, which is of particular concern in South Africa, where many communities are directly and indirectly dependent on wetlands for survival. Two useful wetland assessment tools are currently used in South Africa, but a system that assesses the extent to which wetland ecosystem services (water quality enhancement in particular) are lost as a result of wetland degradation in a landscape context does not currently exist. This study therefore aims to develop a method to determine the cumulative effect of wetland degradation on water quality, which involves the exploration and integration of a number of issues, including land-cover and its effects on water quality, wetland health and its influence on the provision of ecosystem services such as water quality enhancement, and the spatial configuration of wetlands in a landscape, and its effect on water quality at a landscape scale. The method that has been developed is applied to a case study that comprises a quaternary catchment of the upper reaches of the Goukou River Wetlands in the Western Cape of South Africa. Prioritisation criteria are also explored in a series of scenarios, and the criterion and rehabilitation method that gives the best outcome in terms of water quality enhancement is applied to the case study catchment. The workings of the method are scrutinized and benefits and limitations are subsequently highlighted. An important benefit of the methodology is that many previously inadequately explored issues are integrated into a single tool that allows for prioritisation of wetlands for rehabilitation and conservation. This was achieved with South African contexts in mind. Limitations include poor responses by potential questionnaire respondents, while the scope of the study limits the inclusion of detailed aspects which would have further enhanced the accuracy of the tool and of the level of water quality enhancement explored. The methodology that is developed in this research has also not been applied to catchments with good long term water quality data in order to improve its validity. Recommendations for future research are made, which include possible refinement of the system by accounting for factors not included in the current methodology, validation of the system by applying it to a catchment with good water quality data, and the creation of software to make the system easier to use.
Development of census output areas in South Africa.
(2015) Mokhele, Tholang Alfred.; Mutanga, Onisimo.; Ahmed, Fethi B.
The use of the same geographical unit for both census data collection and dissemination is common in many countries across the world, especially in developing countries. This poses some serious concerns. Firstly, this practice has caused various difficulties for the census data users as the ideal characteristics of an area to facilitate efficient census data collection differ considerably from those which aid analysis and interpretation of the published data. Secondly, some Enumeration Area (EA) populations fell below the census confidentiality limits, requiring the data to be combined with those of a nearby EA. Thirdly, the design of EAs before census data collection does not take into account local social divisions in boundary placement. Lastly, the shape compactness of areas is often ignored. In order to address these four concerns, the advanced techniques of automated zone design methods, such as Automated Zone-design Tool (AZTool), are required for the development of suitable output areas in South Africa that would address the four concerns as much as possible. Therefore, the overall aim of this study was to develop optimized census output areas using AZTool program in South Africa. In order to achieve this aim, among others, the following research objectives had been developed; firstly, the creation of output areas using AZTool program with the 2001 census EAs as building blocks in South Africa. Subsequently, the determination of the statistical qualities of the AZTool generated output areas with regard to population target mean, minimum population threshold, social homogeneity and shape compactness was explored. In addition, the comparison of the newly created output areas with existing census small areas was also considered. The study area comprised of two of the nine provinces of South Africa. These included the Free State (representing rural settings) and Gauteng (representing urban areas). This study employed EAs from the 2001 census estimates (HSRC, 2005) as building blocks for creating new census output areas in South Africa. The 2001 census SubPlaces, the 2001 census Small Area Layers (SALs) and 2011 census SALs data were also explored for further evaluation the AZTool program. In order to validate results from the AZTool program, some analyses such Analysis of Variance (ANOVA), Shapirowilk test, paired t-test, and Kolmogorov sminov test were performed using Statistical Package for Social Sciences (SPSS). Results showed that the primary criterion of minimum population threshold of 500 people (which is the official minimum population threshold used by Statistics South Africa) was kept and not breached throughout all the AZTool newly created output areas at different geographical levels as well as in both rural and urban areas. Furthermore, the Intra-Area Correlation (IAC) of 0.62 for the two provinces (Free State and Gauteng) combined indicated that the selected homogeneity variables (geotype and dwelling type) were good indicators of social homogeneity for creating optimised output areas in South Africa. It was also found that the newly AZTool generated census output areas out-performed the existing official SALs and SubPlaces, non-zone design developed geographies. This was proven by the fact that AZTool output areas effectively satisfied minimum and target population thresholds, while the population distributions were much narrower in range than those of the existing SALs and SubPlaces. However, the AZTool created output areas were less compact in shape than the SALs and SubPlaces in all geographical regions. In general, there was statistically significant (p < 0.05) difference in Perimeter Squared per Area (P2A) means between the output areas and the SALs. The LSD post-hoc test revealed that difference between the P2A means for the AZTool output areas and the SALs was not statistically significant (p > 0.05). Therefore, it was concluded that there is potential in application of automated zone design methods, particularly AZTool program, in the creation of optimized census output areas in South Africa. It was also concluded that findings from this study contribute to the research in general and to the potential applications of automated zone design methods in developing countries. One of the main recommendations is that further research and general work should evaluate the application of automated zone design methods, such as AZTool computer program, in the creation of census output areas across the entire country. In addition, data should be made accessible at lower geographical level such as EA or household levels even if it is under secure conditions to allow robust developments of optimized census output areas using automated zone design techniques.
Estimating leaf area index (LAI) of gum tree (Eucalyptus grandis X camaldulensis) using remote sensing imagery and LiCor-2000.
(2001) Mthembu, Sibusiso L.; Ahmed, Fethi B.
The use of remotely sensed data to estimate forest attributes involves the acquisition of ground forest data. Recently the acquisition of ground data (field based) to estimate leaf area index (LAI) and biomass are becoming expensive and time consuming. Thus there is a need for an easy but yet effective means of predicting the LAI, which serves as an input to the forest growth prediction models and the quantification of water use by forests. The ability to predict LAI, biomass and eventually water use over a large area remotely using remotely sensed data is sought after by the forestry companies. Remotely sensed LAI values provide the opportunity to gain spatial information on plant biophysical attributes that can be used in spatial growth indices and process based growth models. In this study remotely sensed images were transformed into LAI value estimates, through the use of four vegetation indices (Normalized Difference Vegetation Index (NDVI), Corrected Normalized Difference Vegetation Index (NDVlc), Ratio Vegetation Index (RVI) and Normalized Ratio Vegetation Index (NRVI). Ground based measurements (Destructive Sampling and Leaf Canopy Analyzer) relating to LAI were obtained in order to evaluate the vegetation indices value estimates. All four vegetation indices values correlated significantly with the ground-based measurements, with the NDVI correlating the highest. These results suggested that NDVI is the best in estimating the LAI in Eucalyptus grandis x camaldulensis in the Zululand region with correlation coefficients of 0.78 for destructive sampling and 0.75 for leaf canopy analyzer. Visual inspection of scatter plots suggested that the relations between NDVI and ground based measurements were variable, with R2 values of 0.61 for destructive sampling and 0.55 for Leaf Canopy analyzer. These LAI estimates obtained through remotely sense data showed a great promise in South African estimation of LAI values of Eucalyptus grandis x camaldulensis. Thus water use and biomass can be quantified at a less expensive and time-consuming rate but yet efficiently and effectively.
A framework for the use of GIS for natural resource management : the case of Ferncliffe catchment conservancy.
(2000) Nsanzya, Kizito Malambo.; Ahmed, Fethi B.
The Ferncliffe Catchment Conservancy has been identified, within the context of Pietermaritzburg, KwaZulu-Natal, for its important geographical and ecological features. The mapping and communication of these features to the broader community resident within the Conservancy have been envisaged as an important undertaking. A most effective way of achieving this goal was to use a Geographic Information System in the mapping exercise and in creating an inventory of the resources in the Conservancy and a monitoring database. Such spatial information would then provide stakeholders with a spatial context within which to appreciate the natural resources available and the problems associated with them. In undertaking this task, spatial data were acquired in digital form as well as from aerial photographs and 1:50000 topo-cadastral maps. These data were imported into ArcView GIS Version 3.1 where the mapping of the various resources was done. An inventory of the resources was created and a spatial database linking attributes that describe the physical environment, the natural vegetation, agricultural activities and the built environment, was set up. It became evident that using a Geographic Information System for natural resource management provides for integration of spatial information which would otherwise be contained in several separate databases and maps. Further, these data can be readily accessed, queried, upgraded and manipulated. For conservancies in urban and rural KwaZulu-Natal, and indeed, the rest of South Africa, to achieve their aims in natural resource management and monitoring, such an approach would be most efficient and effective.
Hydrological flow modelling using Geographic Information Systems (GIS) : the case study of Phuthiatsane Catchment, Lesotho.
(2010) Khalema, Lipalesa.; Ahmed, Fethi B.
Despite of Lesotho having abundant water, it is still faced with freshwater challenges as the current water supply cannot meet the needs of the population. In addition, water has become the main driver of development in Lesotho as it is one of the few natural resources of economic importance hence construction of water storage dams has been identified as a development strategy. Modelling of water flow is one of the techniques used in describing the movement of water and determining flow accumulation within the catchment. Rainfall-runoff modelling in Lesotho has been based on traditional methods which only focus on the discharge at the outlet neglecting the distribution of runoff over the catchment. GIS enables modelling of spatial variability hence this study is aimed at determining flow distribution and accumulation within Phuthiatsane Catchment and estimating runoff potential in a GIS environment. In order to achieve this, ArcHydro extension of ArcGIS was used in the determination of flow distribution and subsequent catchment delineation while ArcCN-Runoff tool was used to determine the potential runoff based on land cover, soil type and amount of rainfall. The delineated catchment covers an area of 468 km2 and has an average runoff of 30.943 MCM. Suitable dam sites, volume and the areas that would be submerged were then identified using other ArcGIS tools. It was concluded that GIS can produce accurate hydrological modelling results for Phuthiatsane Catchment. Simulation of dam sites and storage capacities has also proven to be efficient in GIS environment and a 70m high dam with a storage capacity of 327.92 MCM was considered to be the most suitable. It is recommended that further research should include ground truth surveys for the validation of results. Further research should also incorporate stakeholder concerns in deciding on the location and size of a dam.
Investigating the potential of a classification algorithm to identify black wattle (Acacia mearnsii De Wild.) tress using imaging spectroscopy.
(2012) Agjee, Na'eem Hoosen.; Pillay, A.; Ahmed, Fethi B.
In South Africa, invasive black wattle trees (Acacia mearnsii D. Wild) are a major threat to ecosystem functionality causing widespread social, economic and environmental degradation. It is important that environmental managers are provided with rapid, regular and accurate information on the location of invasive black wattle trees to coordinate removal efforts. This study investigated the potential of an automated image classification algorithm to accurately identify black wattle (A. mearnsii De Wild.) trees using imaging spectroscopy. Hyperspectral data acquired by the EO-1 Hyperion sensor was used to identify black wattle trees in two study areas near Greytown, KwaZulu-Natal, South Africa. Image classifications were performed by the classification algorithm to identify black wattle trees using general and age specific spectral signatures (three to five years, seven to nine years, eleven to thirteen years). Results showed that using the general spectral signature an overall accuracy of 86.25% (user’s accuracy: 72.50%) and 84.50% (user’s accuracy: 69%) was achieved for study area one and study area two respectively. Using age specific spectral signatures, black wattle trees between three to five years of age were mapped with an overall accuracy of 62% (user’s accuracy: 24%) and 74.50% (user’s accuracy: 49%) for study area one and study area two respectively. The low user’s accuracies for the age specific classifications could be attributed to the use of relatively low resolution satellite imagery and not the efficacy of the classification algorithm. It was concluded that the classification algorithm could be used to identify black wattle trees using imaging spectroscopy with a high degree of accuracy.
An investigation into changes in land use/cover patterns in Manganeng area, Limpopo, South Africa.
(2006) Manaka, Martha Patience Rebiditjoe (Budu); Ahmed, Fethi B.
Manganeng area is a communal land with the local community relying on use ofland for their livelihoods. Manganeng shows signs of continued land degradation due to inappropriate land use management, while land use and land cover offer low returns. Continued degradation of natural resources has led to an investigation into changes in land use patterns in the area. Past and present aerial photographs (covering the years 1950, 1964, 1977, 1983 and 1995), recorded and oral history were used as main data sources for investigating changes in land use patterns in the study area. A GIS was also used to quantify the rate of land use change. Data collected from this study aided in providing infonnation about natural resources in the area, how these resources have changed over time and methods used to protect the environment. This study established that from 1950 to 1995, residential land had increased significantly, while farmland and bare rock on Ntswelatau Mountain had increased slightly. Other land cover such as dongas and scattered trees had remained stable over time. Grazing land had decreased significantly while deposited sand and clustered trees decreased insignificantly. A visual change assessment conducted in 2003 indicated that no significant change had occurred in the area since the 1995 aerial photograph was taken. Population growth in Manganeng has led to an increase in residential land use, which directly affected other land uses such as grazing and farmland. The communities' indigenous knowledge has helped in reducing and/or maintaining donga sizes over the past 54 years while restrictions on tree felling on Ntswelatau Mountain has conserved vegetation in the area. Cultivation methods applied in Manganeng are not environmentally sustainable and need to be improved. It is recommended that further research be carried out to assess soil erosion, economic potential, and integration of political/governing powers, as well as levels of agricultural education and awareness among the community. This will ensure an improved understanding of the natural environment in Manganeng, and can provide coping and recovery strategies from stress and shocks of unsustainable resource use in order to preserve these resources for future generations. It is further recommended that the Sustainable Livelihood Framework be adopted in assessing an integrated view of issues related to community based resource management in the area so as to provide insight into priority development options for Manganeng.
An investigation into mapping wetlands using satellite imagery : the case of Midmar sub-catchment.
(2001) Pillay, Dechlan Liech.; Ahmed, Fethi B.
A suitable methodology for mapping wetlands in South Africa has not been agreed upon. This investigation aimed at developing a methodology for the accurate and efficient delineation of wetland areas using satellite imagery and other relevant spatial datasets. Both summer and winter LANDSAT ETM+ satellite imagery covering the study area of the Midmar sub-catchment were processed using various image classification techniques. These included the supervised, unsupervised and level slicing classifications. The accuracy of each technique was tested against the only existing verified wetland dataset that covers the study area. A ground truthing exercise was also undertaken. The different classification techniques resulted in different classification accuracies when compared to the verified wetland dataset. Accuracies for the different classification techniques were as follows: unsupervised 20 class classification (summer) 55%, (winter) 39%, unsupervised 255 class classification (summer) 71%, (winter) 47%; supervised classification (summer) 65%, (winter) 41%; level slicing classification (summer) 65%, (winter) 45%. The inaccuracies could mostly be attributed to a change in land cover as there seems to be an overall loss of wetland areas. However, the ground truthing exercise resulted in higher classification accuracies especially with unsupervised 255 class classification. This study concluded that LANDSAT ETM+ satellite imagery was useful for detecting wetlands areas during summer by using a fine classification technique (255 class). A finer classification technique is also suited for the detection of both large and small wetland areas. Major recommendations include: the use of summer imagery in a high rainfall period; the unsuitability of using winter imagery due to the spectral confusions created; the use of high resolution satellite sensors (SPOT) for monitoring purposes while lower resolution sensors (LANDSAT) should be used for mapping; the increased use of topographical modelling for wetland detection; the use of an appropriate scaled land cover database and the use of field verification exercises for comparing classifications.
An investigation into the classification of river environments using GIS : the case of KwaZulu-Natal rivers.
(2005) Sebake, Malete Daniel.; Ahmed, Fethi B.; Quinn, Nevil Wyndham.
According to the National Water Act No. 36 of 1998 (DWAF 1999), classification of the water resources in South Africa is the initial step towards the implementation of protection or management programmes. This study reviews different methods and systems of classifying river environments, in order to recommend a convenient, efficient and flexible classification scheme for describing the conditions of river environments. To meet this challenge, the study proposes the use of Geographical Information System (GIS) as a tool to link different controlling variables of river environments and thereafter analyse their spatial relationships. The study supports the use of GIS in river environment classification, with special emphasis on its functionalities that make it possible to explore and manipulate data interactively and easily. The GIS allows the user a flexible way to analyse the geomorphologic and ecological controlling variables of the river system. Thus , it enables different arrangements of these controlling variables for a number of classification purposes. The methodology used involves the GIS (database) analyses and map analyses to explore the relationships between geomorphologic and ecological controlling-variables of the river ecosystem. A case study of the KwaZulu-Natal Rivers demonstrates that valuable information for river environments could be derived from available geomorphologic and ecological datasets using methods of analyses within the GIS. In addition, the case study illustrates that it is possible to develop a working classification scheme for a particular purpose. The developed classification scheme can be improved by considering influential factors such as, the use of up-to-date datasets, consistent projection parameters and relevant scale.
An investigation into the detection of sugarcane African stalk borer (Eldana saccharina Walker (Lepidoptera : Pyralidae)) using hyperspectral data (spectroradiometry).
(2009) Mokhele, Tholang Alfred.; Ahmed, Fethi B.
The South African Sugarcane production is one of the world’s leading sugarcane (Saccharum spp. Hybrid) producers. However, in recent years Eldana saccharina Walker has been the most destructive pest in South African sugarcane production, causing great crop loses per annum and is the most important factor limiting sugarcane productivity. The pest has been monitored using a traditional visual approach whereby a representative sample of stalks is taken from a field and split longitudinally to assess damage and count the number of E. saccharina larvae and pupae. However, this approach is time-consuming, labour intensive and sometimes biased as only easily accessible areas are often surveyed. In order to investigate a more economical but equally effective survey methodology, this study aimed to determine the potential of using hyperspectral remote sensing (spectroradiometry) for identifying sugarcane attacked by E. saccharina. A hand-held spectroradiometer ASD Field Spec® 3 was used to collect leaf spectral measurements of sugarcane plants from a potted-plant trial taking place under shade house conditions at the South African Sugarcane Research Institute (SASRI). In this trial, nitrogen (N) and silicon (Si) fertilizers were applied at known levels to sugarcane varieties. Varieties were either resistant or intermediate resistant or susceptible to E. saccharina attack. In addition, watering regimes and artificial infestation of E. saccharina were carefully controlled. Results illustrated that severe E. saccharina infestation increased spectral reflectance throughout the whole spectrum range (400 – 2500 nm) and caused a red-edge shift to the shorter wavelength. Eldana saccharina stalk damage was also linearly related to modified normalized difference vegetation index (mNDVI) using R2025 and R2200 (R2 = 0.69). It was concluded that hyperspectral data has a potential for use in monitoring E. saccharina in sugarcane rapidly and non-destructively under controlled conditions. A followup study is recommended in field conditions and using airborne and/or spaceborne hyperspectral sensors.
An investigation into the spatial and temporal variations in water quality of selected rivers in the Durban Metropolitan Area.
(2002) Pillay, Vineela.; Ahmed, Fethi B.
The spatial and temporal variations in water quality of selected rivers in the Durban Metropolitan Area were investigated using a Geographical Information System. Dissolved oxygen (DO), turbidity, pH, phosphorus and Escherichia coli (E.coli) were selected as water quality parameters for the study. The study reflects a pattern of water quality deterioration due to the numerous land use practices that have had an adverse impact on the receiving waters. In addition, the communities that use this water for various purposes have been impacted on. Spatially, an impoverishment of water quality conditions were observed by the increase of phosphorus, turbidity, DO and E.coli. The parameter of E.coli represented the worst water quality status in all the catchments of the study area. These were attributable to land use factors such as informal settlements and urban formal settlements. For the parameter of pH, no adverse water quality was present. Temporal evaluation of the data indicated that although there were no distinct trends that could be directly related to rainfall, some of the parameters showed some influence by rainfall, through runoff. Selected rivers of the Durban Metropolitan Area reflect poor water quality. There is an urgent need for the implementation of a strategy for improvement. The evaluation of water quality forms the basis for integrated catchment management (ICM), which has been advocated as the only holistic way to manage water resources. Due cognisance must be taken of the various land use practices, which have a great impact on water quality. There should be concerted efforts to reduce the input of pollutants that may have adverse effects on water quality, e.g., by provisions of sanitation facilities in informal settlements. It is hence recommended that for any improvement of water quality to occur, there needs to be an implementation of ICM for all the catchments.
A quantitative assessment of the impacts of water status and chemical bioassays on structural attributes of Eucalyptus clones and plantation soil nitrogen using hyperspectral data.
(2012) Mzinyane, Thamsanqa Donges.; Ahmed, Fethi B.; van Aardt, Jan.
Abstract available in PDF file.
Remote sensing of endangered tree species in the fragmented Dukuduku Indigenous Forest of KwaZulu-Natal, South Africa.
(2016) Omer, Galal Elawad Khaled.; Mutanga, Onisimo.; Abdel-Rahman, Elfatih Mohamed.; Ahmed, Fethi B.
Abstract available in PDF file.
Review of environmental training practices in selected businesses in Durban.
(2015) Sennoga, Dianne.; Gebreslasie, Michael Teweldemedhin.; Ahmed, Fethi B.
Environmental management has moved from a policy concept to a proactive strategy defining business responsiveness to stakeholder and market-related pressures for more environmentally sustainable business practices. Paradoxically, the financial benefits accrued to businesses at the often externalised expense of environmental goods and services, is the very advantage that best positions it to respond to the environmental crisis. The importance of a systematic and proactive environmental response from the business community is compelled by the fact that environmental impacts are predominantly caused by errant pollutant and non-compliant business activities which is increasingly regulated through South African environmental legislation. The business response through corporate sustainability and environmental management is considered a sweeping change to business as usual. Increasing environmental regulations make the adoption of environmental management systems such as ISO 14001 more commonplace. In adapting to these changes in the workplace, it makes environmental training and awareness of employees a material avenue of investigation which further directs the aim of this study. In applying the ISO 14001 certification criterion, through a purposive and nonprobable sampling technique, twenty-four (24) Durban businesses have participated in this study. Similarly, in addition, fifteen (15) employees undergoing environmental training along with five (5) other role-players and stakeholders that relevantly bear on environmental training practices participated in this research, which was conducted through the use of survey questionnaires. The extent of adoption of environmental training and its effective reach across company structures has been assessed against seven (7) developed environmental training principles of this study. The selected businesses and other respondents in Durban show keen awareness, attitudes and perceptions regarding environmental training. Environmental training is a widely practiced activity across all the businesses sampled with topic coverage focussed predominantly on waste management, hazardous chemicals, and environmental auditing. The environmental training activities are largely combined with other Safety and Health priorities. Whilst this has no perceived negative impact on the content of environmental training, there is an indication that environmental training budget allocations are not effectively prioritised in combination with other training activities. The implementation of training across the company tiers shows executive levels in need of greater exposure to this activity. While the respondents predominantly showed limited satisfaction with environmental training received, various areas of improvement became clear such as greater management commitment, greater institutional assistance for clarity of training standards, course offerings and inter-industry collaboration in environmental training.
Spatio-temporal variations of fluoride in surface and ground water : a case study of the Umgeni Water operational area, KwaZulu-Natal.
(2002) Ramjatan, Ashadevi.; Ahmed, Fethi B.
In September 2000 water fluoridation became mandatory in South Africa. Since then water service providers like Umgeni Water (UW), a bulk water supply authority in the KwaZulu-Natal (KZN) province of South Africa began the process of implementing the legislation. This study was undertaken to establish the spatio-temporal variations of fluoride concentrations in surface and ground waters within the Umgeni Operational Area, to establish whether these waters would require fluoridation or defluoridation to meet a fluoride concentration of 0.70 mglf, and to assess the potential impacts of water fluoridation. Baseline fluoride concentrations of surface and ground water: It was concluded that the fluoride concentration of all sample types (rivers, dams, water works raw and final waters, wastewater influent and effluents, and boreholes), except pollution point sources, is less than O.S; mglR, 50 percent of the time. Some rivers (Mshazi, KwaNyuswa, KwaNgcolosi,·Mshwati and the MgoShongweni) exhibited high fluoride concentrations, while someboreholes also exhibited high fluoride concentrations. Temporal Variations and Seasonality: There are seasonal variations in the fluoride concentrations for surface waters, with higher fluoride concentrations in winter than in summer (64 out of 125 occasions). This low fluoride concentration in summer can be attributed to the dilution effects caused by rainfall runoff. Identification of "Hot Spots": "Hot Spots", sites where the fluoride concentration exceeds 1 mglR are present within the study area, for surface and borehole water. For surface water, the MgoShongweni exhibited fluoride concentrations in excess of 1mglRat least 75% of the time. The KwaNgcolosi and Mshwati exhibited fluoride concentrations In excess of 1mglR at least 25% of the time, while the Mshazi and the KwaNyuswa exhibited fluoride concentrations in excess of 1mglR only 5% of the time. The storm water discharge below AECI had high fluoride concentrations in excess of 1mg/R at least 20% of the time and the concentrations exceeded the fluoride concentration for seawater (1.4 mglf) at least 5% of the time. Of the 286 boreholes sampled, 17 boreholes (6% of all boreholes sampled) had fluoride levels in excess oft mglf . The impacts of long term consumption of water from these boreholes could range from slight mottling of the dental enamel in sensitive individuals (boretioles JD26, C29, H19, CB7, 112/1, 69/5, Thembeni 108 and EC (Thembeni 105, Keats Drift boreholes 1 and 2). Spatial patterns and possible sources of high fluoride concentrations: With respect to spatial patterns, relatively high concentrations of fluoride (300 IJglR to 1000 IJglR) can be found in surface water in the Msunduzi river, the Mgeni river downstream of the Msunduzi confluence and along the coastal belt. No spatial patterns are evident with respect to borehole water. For surface water, high fluoride concentrations in the Mshazi, KwaNyuswa and the KwaNgcolosi streams (inflows to the Inanda dam) appear to be associated with the catchment geology. The ~igh fluoride concentrations in Mshwati and the MgoShongweni are most likely as a result of industrial activities in the respective catchments. For borehole water, high fluoride concentrations may be attributed to catchment geology. Additional fluoride dosaqe ' at water treatment works: Since the fluoride concentrations at the water works were low (mean ranging between 0.5 mglf to 0.38 mglf) , fluoride would need to be added to meet the fluoride standard of 0.7 mgl£ . For most of the water works, the additional fluoride (sodium fluoride) requirement to meet the fluoride standard of 0.7 mgl£, ranged from 1.201 kglMRto 1.555 kg/MR. For the water works, Imfume and Umzinto, the additional fluoride , requirement is 0.768 kg/MR and 0.109 kg/MR respectively. In final water, the fluctuations in fluoride concentrations observed would translate to continuous testing being required to maintain optimal dosing of fluoride. Comparison of influent and effluent fluoride concentrations at wastewater works: There was no evidence of fluoride removal at the Mpophomeni Wastewater Works . There was evidence of 22.4% fluoride removal at the DarvHI Wastewater Works possibly due to the activated sludge treatment process at the wastewater works. Future fluoride levels in surface water that will receive return flows: Once water fluoridation is implemented, the Darvill Wastewater Works would receive fluoridated return flows, and discharge its fluoride rich effluent into the Msunduzi river. The average monthly fluoride road discharged from Darvill Wastewater Works would increase from 0.23 tons to 1.46 tons, an additional 1.23 tons per month on the aquatic environment of the Msunduzi river. The sludge fluoride load, disposed to land, could increase from 4 056 tons/month to 27 863 tons/month, which implies an increase in the fluoride runoff potential from the sludge-lands to the Msunduzi river. Number of people in sensitive groups that could be affected by water fluoridation: A significant number of people in KZN could be sensitive to water fluoridation. This has been estimated to be at least one third of KZN's population that are HIV infected. Recommendations were made and the most important ones are as follows: In the light of the large number of people, one-third the population of KZN, that is HIV positive and therefore could be sensitive to fluoridated water, it is recommended that the South African legislation mandating water fluoridation be withdrawn. Examination of the most recent literature indicated a significant lack of confidence in the best available studies that researched the safety and efficacy of water fluoridation. In the light of this it is recommended that the South African Department of Health re-examine and withdraw its legislation that mandates water fluoridation.
A suitability assessment of farms for inclusion in a UNESCO-approved biosphere reserve : the case of the Itala Biosphere Reserve, KwaZulu-Natal.
(1997) Moffat, Andrew John.; Granger, James Edmund.; Klug, John R.; Ahmed, Fethi B.
This project describes and evaluates a method of assessing the suitability of 161 farms for inclusion in a biosphere reserve. Farms were chosen as a basic study unit over more ecologically based units because the decision to participate in the biosphere reserve rests with the landowner. The study area is located in northern KwaZulu-Natal, between Hlobane, near Vryheid, and the Itala Nature Reserve where local landowners are exploring the possibility of establishing a biosphere reserve. A brief review of the natural, social and economic contexts is given in order to identify local dynamics relevant to the establishment of a biosphere reserve. Farm suitability for inclusion was assessed with respect to its capability to fulfil the three main roles of a biosphere reserve as defined by the Man and Biosphere Programme of UNESCO. These are conservation, sustainable development and research. Ten factors were identified to determine farm suitability: vegetation, fauna and soil conservation, present land use, agricultural potential, tourism potential, education, settlement density and location. These were prioritised using the Analytical Hierarchy Process according to their impact on the main roles of the biosphere reserve.Each farm was given a factor score according to the expression of that factor on that farm. Overall farm suitability was taken as the sum of the weighted factor scores. The final scores for each farm were grouped into suitability classes and these were mapped. This map was then used to make recommendations on which farms should be considered for inclusion in the reserve. This method of assessing farm suitability for inclusion in a biosphere reserve, involving scoring the factors determining suitability and prioritising these factors was evaluated with respect-to its efficiency in identifying suitable properties. This was achieved by comparing the results of the assessment with the suitability class of farms with known suitability. The conceptual approach to the assessment was reviewed against published guidelines for integrated regional planning and rational resource planning. The accuracy of the project method in correctly identifying suitable farms was assessed against two other simplified methods of assessment, involving no weighting between factors, and a limited number of factors. Based on these analyses, conclusions have been drawn as to the strengths and weaknesses of both the method of farm assessment and the method of evaluation itself Recommendations were made for further research into and development of methods of assessing farm suitability for biosphere reserves. A procedure for the establishment of the proposed Itala Biosphere Reserve was suggested.

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