Smallholder irrigation has been promoted across the developing world as a means of poverty reduction and rural development. The potential of smallholder irrigated agriculture in alleviating rural poverty has led the South African government to prioritise and invest in irrigation establishment, rehabilitation and revitalisation. However, the extent to which smallholder irrigation has been able to reduce poverty in the rural areas of South Africa is not well understood. This study, therefore, aimed to contribute to smallholder irrigation literature in two ways. The first objective of this study was to conduct an in-depth impact evaluation of the Tugela Ferry smallholder irrigation scheme on household welfare using the treatment effect and propensity score matching (PSM) methods. Secondly, the study sought to investigate the determinants of household water security, and how the level of water security subsequently affects the farmers’ household welfare. A stratified random sampling technique was used to obtain a sample of 186 irrigators and 70 non-irrigators in the Tugela Ferry area. Descriptive analysis highlighted that although the demographic characteristics of the farmers were not significantly different, the irrigators were characterized by better welfare indicators compared to non-irrigators. The Foster Greer Thorbecke (FGT) poverty indices also indicated that poverty incidence was more pronounced among non-irrigators than among irrigators. The results from the econometric models indicated that irrigation access plays an important role in the welfare of rural households, with irrigators consuming about R2,000 per adult equivalent per year more than the non-irrigators. While irrigation access is important, this study concluded that the poverty reduction effectiveness of smallholder irrigation can further be enhanced by ensuring that the irrigators are water secure. Factors such as age, off-farm income, duration of scheme membership, occurrence of conflicts, method of pumping water, location in the scheme and access to agricultural training influenced household water security. The study recommends that investments in smallholder irrigation should continue for poverty reduction, and that priority should be in ensuring water security not just irrigation participation. The study also recommends the introduction of small motorised pumps among the gravity-reliant irrigators and farmer training on water conservation techniques to improve the farmers’ water security in the smallholder irrigation schemes. Although the study highlighted how perceptions of irrigators could be used to generate the water security index, the water security concept needs further investigation. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Thesis--University of Natal. / Cover title: A plant ecology survey of the Tugela River Basin, Natal. Bibliography: p. 281-285.

Thesis--University of Natal. / Cover title: A plant ecology survey of the Tugela River Basin, Natal. Bibliography: p. 281-285.

Water scarce countries such as South Africa are subject to various hydrological constraints, particularly within resource poor farming communities that are reliant on rainfed agriculture. Recent initiatives to address this issue have shifted focus to explore more efficient alternatives to water supply. Adoption of water system innovations through the use of runoff harvesting is one such alternative that provides a means to supplement water use for increased food production. However, increasing the implementation of runoff harvesting, without encountering unintended impacts on downstream hydrological and ecological systems, requires better understanding of the hydrologic and environmental impacts at catchment scale. The objective of this dissertation was to gain knowledge to the ecohydrological impacts that are likely to occur with the adoption of water system innovations as a means for upgrading rainfed smallholder farming systems. To fulfil this objective, a research component was developed whereby tools were utilised to facilitate this process on the basis of two broad aims. The first aim entailed developing a method for locating areas that are most suitable for the adoption of runoff harvesting using Geographical Information Systems (GIS). This was achieved by spatially modelling physical properties of the landscape which influence runoff response. Combining potential runoff with socio-economic factors produced a runoff harvesting map of sites with low, medium and high suitability. This is illustrated by a case study at the Potshini catchment, a small sub-catchment in the Thukela River basin, South Africa. The second aim involved modelling the impacts that runoff harvesting would have on the downstream hydrology and ecology based on the alteration of the flow regimes. To accomplish this, the ACRU Agrohydrological model which was configured to represent runoff harvesting, was used to simulate streamflow for quaternary catchments within the headwaters of the Thukela River basin. Simulated streamflows from ACRU was input into the IHA model to generate ecologically relevant hydrological parameters. Alteration of the flow regime due to runoff harvesting was mostly a reduction in high and low flows however the impacts were insignificant. This suggests that, depending on the intensity of runoff harvesting, downstream ecological impacts are insignificant. / Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2009.

The by-catch of penaeid prawn trawlers operating on the Tugela Bank of Natal was analysed at irregular intervals for a period of three years, from May 1989 to June 1992. This was primarily in response to claims by Iinefishermen that trawlers were catching and discarding juvenile Iinefish species. Catch and effort data were recorded from 159 trawls, and catch composition data from 110 trawls, over a depth range of 20 to 45 meters. A total of 108 teleost species were identified in the by-catch, six of which comprised 80 percent of overall teleost abundance by number. Many of these fish were small-sized shoaling species, which increased their vulnerability to trawlers, and the majority were considered to be estuarine-associated. Multivariate analysis of samples showed there to be significant differences in relative abundance of species by season and depth. Annual average by-catch and discarded quantities were estimated at 400 and 315 tonnes respectively. Discard:retained catch ratios' ranged from 4.25 (± 1.19) : 1 to 15.48 (± 3.86) : 1 for shallow (20-33 meters) and deep (33-45 meters) trawls respectively. Only one important Iinefish, the squaretail kob, Argyrosomus thorpei, occurred in prawn trawl catches. These fish were spawned four to six months prior to being caught and appeared to use the Tugela Bank as a nursery area. They were seasonally abundant, occurring mostly from January to March. During these months trawling effort was generally low, as the prawns had not yet migrated offshore in quantity. Per-recruit analyses showed that the removal of these age 0 fish by trawlers reduced yield-per-recruit and spawning biomass-per-recruit values for the A. thorpei fishery. Aspects of the biology of three common sciaenids occurring in trawl catches, Johnius dussumieri, J. amblycephalus and Otolithes ruber, were investigated. Most of the fish examined were juveniles which utilised the Tugela Bank as a nursery area, owing to the existence of suitable food, and the turbid waters afforded them protection from predators. Standard biological data, such as length frequencies, lengthweight relationships and size at 50% maturity are presented. Based on the data collected and the analyses presented here, management recommendations are presented, which include the improvement of the collection of catch and effort data for the Tugela Bank prawn trawlers; communication of the results of this study to prawn trawler operators in order to encourage the reduction of trawling effort early in the year; consideration to be given to the re-surveying of Tugela Bank ichthyofaunal by-catch in the future in order to assess potential long-term effects of trawling in the area. / Thesis (M.Sc.)-University of Natal, 1993.

In this study, geophysical measurements (Electrical Resistivity Tomography-ERT) and remote sensing techniques were applied in the Thukela river basin at various scales to complement the classical hydrometeorological networks. Detailed process hydrological studies were carried out at the Potshini catchment in the Thukela river basin to provide an in-depth understanding of the influence of different land use management practices, notably the impact of conservation tiJlage practices, on runoff generation and soil moisture retention characteristics at field scale. The general trend that was observed in the field studies is that conservation tillage systems influenced the partitioning of rainfall, by significantly reducing surface runoff over agricultural lands under conservation tillage practices, with a reduction ranging from 46 to 67%. The field soil-water balance studies also indicated that more soil moisture was retained in plots under conservation tillage practices compared to plots under conventional tillage and hence the wider adoption of such a practice could influence the partitioning of rainfall across scales. The field based study was integrated into catchment process studies where a classical hydrometrical network was complemented with geophysical measurements (ERT) along catchment transects to determine the interaction of the surface and sub-surface water and the relative contribution of the subsurface water to catchment response. The study revealed that the shallow ground water contributes significantly, close to 75%, of the stream flows in the Potshini catchment, especially during the dry seasons, with the response of the shallow ground water being a function of both the rainfall intensity and daily total amount. The potential of integrating the catchment process studies with the larger river basin scale was explored through the evaporative term of the water balance by applying the Surface Energy Balance Algorithm for Land (SEBAL), a remote sensing methodology, to estimate total evaporation (ET) from the Moderate Imaging Spectroradiometer (MODIS) satellite images. This was validated with ground measurements from a Large Aperture Scintilometer (LAS) installed in the Potshini catchment. Good comparison was established between the remotely sensed estimates and LAS measurements with a deviation range of between -14 to 26% on discrete days, where the deviation was defined as the departure of the remotely sensed estimates of ET from the respective LAS measurements. The results from this study compare well with results from similar studies in other countries with different climatic conditions. Subsequently, the evaporative water use of various land uses in the upper Thukela river basin was assessed using MODIS images. Commercial forestry was identified to be the land use with a consistent and relatively high evaporative water use In the study area. High evaporation rates over water bodies were observed during the wet summer season when both the natural and man made water bodies were at full capacity. Nevertheless, it is recognized that the inherent low resolution ofthe MODIS images could have impacted on the SEBAL results. Finally, a conceptual framework, drawing the strengths of classical hydrometeorological networks, geophysical measurements, isotope tracers and remote sensing is suggested with the potential of enhancing our understanding and conceptualization of hydrological determinants across scales. The relevance of the framework to water resources management is highlighted through its application to the Potshini catchment and the Thukela river basin using results and findings from this study. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2008.

This study examines foredune evolution along a 2100 m section of coast adjacent to the Tugela River. The foredunes vary in both height and shape along the study area and form the southern most extension of the Tugela foredune-ridge plain. Sand accumulation and erosion was measured at regular intervals over a 30 month period by tacheometric surveys. The foredunes and beaches are comprised of over 99 % sand. The sediment was predominantly composed of quartz and feldspar with subordinate lithic fragments. The quartz grains display conchoidal fractures and mechanical v-shaped pits and curved grooves. The beach and dune sand is well sorted and slightly negatively skewed with a mean grain size of 1.62 ф. The vegetation structure and floristic composition of the foredunes are explored. A range of factors influencing foredune morphology and evolution, including canopy density, height and distribution, wind velocity and a variety of ecological and environmental processes are examined. Ridge and swale morphology as well as alongshore variation in the dunefield could not be related to biological processes. The development of a foredune-ridge topography depends on a large sediment supply from the Tugela River over the long-term. Periods of high discharge introduce a fresh source of sediment to the littoral zone. Reworking of fluvial sediment landwards results in wide beaches. Onshore winds transport the sand from the beaches to the foredunes. Scaevola thunbergii encourages rapid vertical accretion and hummock dunes are formed. Lateral extensive invasion by seedlings may result in the hummock dunes joining to form coast parallel foredunes. Under periods of reduced sediment discharge erosion of the shoreline results in steep narrow beaches. Despite a negative beach budget foredunes continue to accrete vertically. Marine erosion results in either the complete destruction of embryo foredunes or their landward shift. Natural breaks in the dune crestline were attributed to changes in the delivery of sediment to the beaches. The processes operating in the study area conform to Psuty's (1988,1989) sediment budget model of foredune development. Sediment availability to the coastline produces characteristic morphologies. / Thesis (M.Sc.)-University of Natal, Durban, 1998.

Printed information access, preferences and use by small-scale farmers in KwaZulu-Natal, who are experimenting with or converting to organic farming, were investigated to establish the need for information on organic production, certification, and marketing. Forty-six resource-poor farmers from four groups at Umbumbulu, Tugela Ferry, KwaMashu and Muden participated in semi-structured group interviews. Guiding questions, information tabulation, ranking and sorting, and voting were used to gather data. Five printed agricultural information materials were evaluated. The findings indicated that the participants trusted and relied on intermediaries for access to innovative, research-based information, and preferred interpersonal communication over other information channels. Printed materials were valued for their permanence, while participants preferred materials in isiZulu as 75% of participants were able to read and write isiZulu or were able to ask family members to read materials in isiZulu. At least one functionally literate farmer was a member of each of the participating farmer groups. Appropriate printed information on organic production, certification and marketing had not reached the participants. Characteristics of printed information materials preferred by participating farmers included: large typeface, photographs, drawings, step-by-step instructions, stories about people and events, context-specific content, the use of plain language in English or preferably isiZulu. / Thesis (M.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.