Academic literature on the topic 'Rivers – South Africa'
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Journal articles on the topic "Rivers – South Africa"
1
Smedley, D. A., and K. M. Rowntree. "Rivers as borders, uniting or dividing? The effect of topography and implications for catchment management." Water Science and Technology 66, no. 3 (2012): 510–16. http://dx.doi.org/10.2166/wst.2012.186.
Full textAbstract:
South Africa's water resources are unequally distributed over space and time and an already stressed water resource situation will only be exacerbated by climate change if current predictions are correct. The potential for conflict over increasingly strained water resources in South Africa is thus very real. In order to deal with these complex problems, national legislation is demanding that water resource management be decentralized to the local level where active participation can take place in an integrated manner in accordance with the principles of Integrated Water Resource Management (IWRM). However, administrative and political boundaries rarely match those of catchments as, throughout South Africa, rivers have been employed extensively to delineate administrative and political boundaries at a number of spatial scales. The aim of this research is to determine if rivers act as dividing or uniting features in a socio-political landscape and whether topography will influence their role in this context. The Orange-Senqu River is used as a case study. This paper goes on to consider the implications of this for catchment management in South Africa. No study known to the authors has explored the effect of the river itself, and its topographic setting, on the drivers that foster either conflict or cooperation, and allow for participatory management. This study presents evidence that the topography of a catchment has the ability to aggravate or reduce the impact of the variables considered by water managers and thereby influence the role of a river as a dividing or uniting feature. South Africa's proposed form of decentralized water management will have to contend with the effects of different topographies on the way in which rivers are perceived and utilized.
2
Khumalo, Nomcebo, Aloyce W. Mayo, and Subira Munishi. "Modelling Of Food Hazard Susceptibility in Komatipoort, South Africa." Tanzania Journal of Engineering and Technology 37, no. 1 (2018): 47–71. http://dx.doi.org/10.52339/tjet.v37i1.483.
Full textAbstract:
Komatipoort, a small town located at the confluence of Komati and Krokodil rivers, is constantly being hit by floods which affect the residents of this small town as well as the farmers settling along the rivers. This study aimed at mapping the flood hazard and susceptibility through the integration of GIS techniques and hydraulic modeling. Due to inconsistency in the length of streamflow data in the different gauging stations, a Hydrological modeling HBV model, was utilized for modelling runoff in order to extend flow records at station X2HO32 for Komati River. Calibration was conducted using observed data from 1982 to 1993, giving an efficiency value of 65% and validation was done using data from 1993 to 1999, giving an efficiency value of 53%. Flood frequencies were analyzed and flood quantiles were determined at different return periods. HEC-RAS was utilized to simulate the hydraulic parameters of Komati and Krokodil rivers to obtain flood hazard maps. GIS-based multi-criteria analysis techniques were incorporated for flood susceptibility mapping. Hydraulic analysis showed that the floods mostly affect the farms and settlements along the rivers and a small part of the central business district is affected. Flood susceptibility mapping showed that the area is generally highly susceptible to flooding because of a combination of anthropogenic and natural factors.
3
Grenfell, S., and M. Grenfell. "Characterising the late Quaternary facies stratigraphy of floodplains in South Africa." South African Journal of Geology 124, no. 4 (2021): 963–76. http://dx.doi.org/10.25131/sajg.124.0056.
Full textAbstract:
Abstract South African river floodplains and their alluvial deposits reflect a diversity of geological and geographical drivers. We use a genetic geomorphic classification system originally developed for dryland wetlands to characterise geomorphic processes and potential successions of sedimentary fill for South African floodplains. Using case studies from the literature, we consider differences between alluvial rivers and mixed bedrock-alluvial rivers in the context of macro-scale geomorphic setting, and evaluate the impact of the setting on floodplain persistence and potential as a palaeo-environmental archive. Sedimentary facies associations represented in South African floodplains, including lateral and oblique accretion, channel, channel infill, levee vertical accretion, floodplain vertical accretion and debris flow deposits, are also evaluated. Floodplains of South Africa’s interior are typically mixed bedrock-alluvial as channel beds are set upon or close to bedrock and sediment thickness is limited. By contrast some floodplains in tectonic basin settings have sediment deposits exceeding 30 m in thickness. The resulting rivers are alluvial, and thus able to adjust their width, depth and slope to accommodate changes in discharge and sediment supply. Similarly, coastal floodplain rivers are alluvial due to downcutting during the last glacial maximum and subsequent sedimentary infilling as sea levels rose. When considering the potential of floodplains as palaeoarchives of environmental change, two considerations emerge. First, floodplain stratigraphy is not a response to a single variable due to complex process-form feedbacks. Rather, floodplain stratigraphy is an outcome of both autogenic and allogenic processes. Second, most South African floodplains are zones of sediment recycling, and as such, preservation potential is typically low. Thus, although floodplain settings of the interior may be a few million years old, the sediment within them may be only thousands to tens of thousands of years old. Our review indicates that research has historically focused on meandering river and mixed bedrock-alluvial anabranching river floodplains, while understanding of other floodplain sub-types remains limited.
4
Murray, T. Y., J. Mans, and M. B. Taylor. "First detection of human sapoviruses in river water in South Africa." Water Science and Technology 67, no. 12 (2013): 2776–83. http://dx.doi.org/10.2166/wst.2013.203.
Full textAbstract:
Over a 2-year period, from January 2009 to December 2010, water samples were collected from three rivers (Klip, Rietspruit and Suikerbosrand) in the Vaal River System, South Africa. Enteric viruses were recovered by a glass wool adsorption–elution method and concentrated using polyethylene glycol/sodium chloride precipitation. Sapoviruses (SaVs) were detected using published sapovirus (SaV)-specific primers and Taqman probes in a two-step real-time reverse transcription-polymerase chain reaction assay. Based on sequence analysis of the 5′-end of the capsid gene, SaVs were genotyped. In 2009, SaVs were detected in 39% (15/38) of samples from the Klip river, 83% (5/6) from the Rietspruit and 14% (1/7) of samples from the Suikerbosrand river. In 2010, SaVs were detected in 54% (14/26) of Klip river samples, 92% (11/12) from the Rietspruit and 20% (2/10) of samples from the Suikerbosrand river. SaV strains identified in the water samples were characterised into several GI and GII genotypes. The presence of SaVs in these rivers indicates human faecal contamination which may pose a potential health risk to persons exposed to these water sources during domestic or recreational activities.
5
Mudumbi, J. B. N., S. K. O. Ntwampe, F. M. Muganza, and J. O. Okonkwo. "Perfluorooctanoate and perfluorooctane sulfonate in South African river water." Water Science and Technology 69, no. 1 (2013): 185–94. http://dx.doi.org/10.2166/wst.2013.566.
Full textAbstract:
This study examined the prevalence of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in river water samples (n = 56) and suspended solids (n = 5) from three major Western Cape rivers, in South Africa. Solid phase extraction (SPE) followed by liquid chromatography combined with electrospray tandem mass spectrometry (LC-MS/MS) using an analytical method developed in ISO 25101 (2009), PFOS and PFOA concentration in river water and in suspended solids from the rivers was investigated and quantified. From the results, PFOA and PFOS were detected in all the river water samples and were found in concentrations up to 314 and 182 ng/L for Diep River; 390 and 47 ng/L for Salt River; and 146 and 23 ng/L for Eerste River, respectively. In suspended solids, concentrations for PFOS and PFOA were 28 and 26 ng/g for Diep River; 16 and less than limit of detection for Eerste River; and 14 and 5 ng/g for Salt River, respectively. Some of these concentrations are higher than those previously reported in similar studies in various countries, and this suggests there is a cause for concern, in the Western Cape, South Africa, particularly in catchments where river and ground water is drawn for agricultural purposes in the province.
6
Archibald, C. G. M., and J. C. Taylor. "The assessment of diffuse pollution from acid-mine drainage using an updated and revised diatom assessment procedure as an added-value bio-monitoring tool." Water Science and Technology 55, no. 3 (2007): 151–60. http://dx.doi.org/10.2166/wst.2007.083.
Full textAbstract:
Three data sources (physico-chemistry, bio-monitoring and eco-toxicology) are currently used in South Africa to establish environmental water quality conditions. Environmental water quality in turn is key information required for the “ecological reserve determination” of river reaches. Bio-monitoring in South Africa has been limited in recent times mostly to the use of the SASS procedure which relies on invertebrates only. This paper describes the re-introduction of a diatom-based water quality assessment as an added-value bio-monitoring tool. A specific example is discussed citing the response of diatom assemblages to diffuse pollution from acid mine drainage and how effective diatoms are as indicators of ecological integrity and river recovery measured downstream of the area of impact. The advantages of applying this bio-monitoring technique over other biological measures are presented in the context of technological advances in rapid image processing, species identification and software applications of diatom-based water quality indices. The valuable records of the diatom assemblages of the past, held in the South African Diatom Collection at the CSIR (KwaZulu-Natal), can now be accessed and interpreted as historical environmental water quality reference points for several rivers in South Africa.
7
MANS, J., R. NETSHIKWETA, M. MAGWALIVHA, W. B. VAN ZYL, and M. B. TAYLOR. "Diverse norovirus genotypes identified in sewage-polluted river water in South Africa." Epidemiology and Infection 141, no. 2 (2012): 303–13. http://dx.doi.org/10.1017/s0950268812000490.
Full textAbstract:
SUMMARYThis study aimed to assess norovirus (NoV) contamination and genotype diversity in surface water in Gauteng, South Africa. Between January 2008 and December 2010, three rivers, namely Klip, Suikerbosrant, and Rietspruit were monitored for NoV genogroup (G)I and GII. Viruses were recovered using the glass wool adsorption-elution technique and detected by real-time reverse transcription–polymerase chain reaction. From 2008 to 2010, NoVs were detected in 66% (70/106) of Klip river samples. The Rietspruit and Suikerbosrant rivers were contaminated with NoV in 95% (20/21) and 21% (5/24) of samples, respectively. NoV-positive samples comprised of 33% GI, 29% GII and 38% of both GI and GII strains. Based on partial capsid gene analysis (region C), 16 NoV genotypes (6 GI, 10 GII) were identified. The major genotypes detected were GI.4, GI.5 and GII.4. These rivers could be a potential source of NoV infection for communities using the water for domestic or recreational purposes.
8
Blamey, R. C., A. M. Ramos, R. M. Trigo, R. Tomé, and C. J. C. Reason. "The Influence of Atmospheric Rivers over the South Atlantic on Winter Rainfall in South Africa." Journal of Hydrometeorology 19, no. 1 (2018): 127–42. http://dx.doi.org/10.1175/jhm-d-17-0111.1.
Full textAbstract:
Abstract A climatology of atmospheric rivers (ARs) impinging on the west coast of South Africa (29°–34.5°S) during the austral winter months (April–September) was developed for the period 1979–2014 using an automated detection algorithm and two reanalysis products as input. The two products show relatively good agreement, with 10–15 persistent ARs (lasting 18 h or longer) occurring on average per winter and nearly two-thirds of these systems occurring poleward of 35°S. The relationship between persistent AR activity and winter rainfall is demonstrated using South African Weather Service rainfall data. Most stations positioned in areas of high topography contained the highest percentage of rainfall contributed by persistent ARs, whereas stations downwind, to the east of the major topographic barriers, had the lowest contributions. Extreme rainfall days in the region are also ranked by their magnitude and spatial extent. The results suggest that although persistent ARs are important contributors to heavy rainfall events, they are not necessarily a prerequisite. It is found that around 70% of the top 50 daily winter rainfall extremes in South Africa were in some way linked to ARs (both persistent and nonpersistent). Overall, the findings of this study support similar investigations on ARs in the North Atlantic and North Pacific.
9
Potgieter, Natasha, Simbarashe Karambwe, Lutendo Sylvia Mudau, Tobias Barnard, and Afsatou Traore. "Human Enteric Pathogens in Eight Rivers Used as Rural Household Drinking Water Sources in the Northern Region of South Africa." International Journal of Environmental Research and Public Health 17, no. 6 (2020): 2079. http://dx.doi.org/10.3390/ijerph17062079.
Full textAbstract:
People living in rural areas still rely on the use of environmental water that is contaminated by human and animal activities. This study assessed the occurrence of human enteric pathogens in rivers that are used by rural communities Vhembe District of South Africa as a source of drinking water covering two seasons (winter and summer) over a one-year period. Water quality was assessed using physico characteristics and indicator organisms (total coliforms, E. coli, Clostridium perfringens). Pathogens tested included bacteria (Pathogenic E. coli, Salmonella-, Shigella- and Vibrio spp.), protozoa (Cryptosporidium- and Giardia spp.), and enteric viruses (Rota-, Noro-, Entero-, and Adenoviruses) while using published molecular protocols. The results showed that the indicator bacteria counts exceeded South African drinking water quality guideline limits and pathogenic E. coli was detected in the samples. No Shigella spp. were isolated, while Vibrio spp. and Salmonella spp. were present; parasites were detected in four rivers and Enteric viruses were predominantly detected in the winter season. The results indicated the poor condition of water and the potential health risks to consumers highlighting the need for implementing river catchment management strategies for continued sustainability in these rivers.
10
Cloete, E. C., and R. A. Lubke. "Flora of the Kap River Reserve, Eastern Cape, South Africa." Bothalia 29, no. 1 (1999): 139–49. http://dx.doi.org/10.4102/abc.v29i1.585.
Full textAbstract:
A detailed analysis ot the flora of the newly proclaimed Kap River Reserve (600 ha) is given. The reserve is adjacent to the Fish River and some 5 km from the Fish River Mouth It consists of a coastal plateau up to 100 m a.s.I. which is steeply dissected by the two rivers that partially form the boundary of the reserve. The flora of the reserve was sampled over a period o f three years and plants were collected in all the vegetation types of grassland, thicket and forest. 488 species were collected with a species to family ratio of 4:4. The majority of the taxa recorded represent the major phytochoria of the region. Nineteen species are endemic to the Eastern Cape, two are classed as vulnerable, five are rare, six are protected and a further seventeen are of uncertain status. The flora of the Kap River has closest affinities to that of the Alexandria Forest.
Dissertations / Theses on the topic "Rivers – South Africa"
1
Newman, Natalie Nicolette. "The impact of altered river structure on the function of selected urban Cape Town rivers." Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/2029.
Full textAbstract:
Thesis (MTech (Nature Conservation))--Cape Peninsula University of Technology, 2010.<br>Many urban rivers are heavily engineered and no longer function naturally. The City
of Cape Town has designed and implemented many stormwater and river
management projects. Very little monitoring has occurred as to whether these
engineering projects and remediation measures, have had a positive effect on our
urban river ecosystem function.
The study investigated the influence of specific engineering interventions such as the
placement or rocks in stream to create weirs, gabion lining of stream channels,
removal of canal walls, establishment of artificial wetlands, and approaches to urban
river management, on river ecosystem function of the Keysers River, Little Lotus
River, Langevlei Canal, Silvermine River, Moddergat River and Big Lotus River, as
measured by specific indices including water chemistry and aquatic community
structure (macroinvertebrates and diatoms).
2
Hayes, Johan Barnard. "Assessment of fish as bio-indicators of river health in rivers of the southwestern Cape." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52704.
Full textAbstract:
Thesis (MSc)--University of Stellenbosch, 2002.<br>ENGLISH ABSTRACT: In this study, the Fish Assemblage Integrity Index (FAll) was applied on three rivers within the
southwestern Cape. This index uses fish as indicators of biological aquatic integrity and is based on
indigenous species expected to be present in biological fish habitats. Fish integrity classes were
calculated for each of the sites in the three rivers studied. Sites 2 and 4 within the Lourens River
were rated as Class C, whereas sites 1 and 3 were rated as Class F and Class D respectively. Sites
1, 2 and 4 within the Palmiet River were rated Class F, whereas sites 3 and 5 were rated as Class E
and Class D respectively. Site 1 within the Hout Bay River was rated as a Class F site, in addition to
sites 2 and 3 been rated as Class A. It is however, suggested that the FAll needs to be adjusted to
accommodate the general low species richness experienced in the southwestern Cape. In addition to
the FAll been applied, the effects of long-term exposure to subtle water quality changes associated
with human activities, specifically potential estrogenic compounds in fish from the Lourens River
were also investigated. The production of the yolk precursor lipoprotein complex, vitellogenin (Vtg)
produced in the liver under estrogen control was employed as biomarker for environmental estrogen
exposure. Male fish from the Lourens River were studied using SDS-PAGE gel electrophoresis.
Results indicated that 60% of male fish showed the presence of Vtg in their plasma. Abnormal
gonad morphology in male and female fish were also assessed using standard histological
procedures. Results from this study indicated no observed abnormalities in either male or female
gonads. The immediate presence of endocrine disrupters with estrogen activity was investigated by
screening water samples from the Lourens, Palmiet and Hout Bay Rivers for estrogen activity.
Results indicated that none of the samples appeared to be cytotoxic. In addition, estrogen activity of
water samples was also investigated by in vitro culturing of water samples with frog, Xenopus
laevis, liver slices. Results indicated that none of the water samples from the three rivers studied
indicated estrogenic activity. Although cytotoxicity and estrogen activity results were negative, the
production of Vtg in male fish suggests further research regarding the presence of estrogenic
substances in these rivers.<br>AFRIKAANSE OPSOMMING: In die huidige studie is die 'Fish Assemblage Integrity Index' (FAIl) toegepas op drie rivere in die
suidwes Kaap. Hierdie indeks gebruik visse as bioindikatore van biologies akwatiese integriteit en
is gebasseer op die inheemse visspesies wat verwag word in biologiese vishabitatte.
Integriteitsklasse is bepaal vir elke studieterrein in die drie rivere wat ondersoek is. 'n Klas C is
bepaal vir studieterreine 2 en 4 in die Lourensrivier. Klas F en Klas D is bepaal vir studieterreine 1
en 3 in die rivier onderskeidelik. 'n Klas F is bepaal vir studieterreine 1, 2 en 4 en Klas E en Klas D
bepaal vir studieterreine 3 en 5 in die Palmietrivier onderskeidelik. 'n Klas F is bepaal vir
studieterrein 1 in die Houtbaairivier waar 'n Klas A bepaal is vir studieterreine 2 en 3. Dit word
egter voorgestel dat die FAII aangepas moet word om die algemene lae spesierykheid wat ervaar
word in die suidwes Kaap te akkomodeer. Die reaksie van visse, afkomstig van die Lourensrivier,
op die langtermyn blootstelling aan estrogeniese stowwe is ook bestudeer. Spesifieke reaksies van
endokriene versteuring, soos vitellogeen (Vtg) produksie in manlike visse is ondersoek deur middel
van SDS-PAGE gel elektroforese. Resultate toon dat in 60% van die manlike visse Vtg in die
plasma teenwoordig was. 'n Ondersoek na abnormale gonade morfologie in manlike en vroulike
visse van die Lourensrivier is deur standard histologiese prosedures gedoen. Resultate hiervan dui
op geen sigbare abnormaliteite in die gonades nie. Die onmiddelike teenwoordigheid van
endokriene versteurders is bestudeer deur die sitotoksisiteit van watermonsters afkomstig van die
Lourens, Palmiet en Houtbaai riviere te bepaal. Resultate dui aan dat geen monsters sitotoksies was
nie. Die estrogeenaktiwiteit van die watermonsters is ook ondersoek deur van in vitro kulture van
watermonsters saam met padda, Xenopus leavis, lewersnitte gebruik te maak. Geen estrogeniese
aktiwiteit is in die watermonsters gevind nie. Al is die sitotoksisiteit en estrogeenaktiwiteit resultate
negatief, dui die produksie van Vtg in manlike visse op die noodsaaklikheid van verdere navorsing
ten opsigte van die teenwoordigheid van estrogeniese stowwe in drie riviere.
3
Dollar, E. S. J. "The determination of geomorphologically effective flows for selected eastern sea-Board Rivers in South Africa." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1005499.
Full textAbstract:
In South Africa the need to protect and manage the national water resource has led to the development of the Reserve as a basic right under the National Water Act (1998). The Ecological Reserve relates to the quality and quantity of water necessary to protect the sustainable functioning of aquatic ecosystems. The geomorphological contribution to setting the Reserve has focussed on three groups of information requirements: the spatial and temporal availability of habitat, the maintenance of substratum characteristics, and the maintenance of channel form. This thesis focusses on the second and third information requirements. The thesis has attempted to achieve this by adding value to the theoretical and applied understanding of the magnitude and frequency of channel forming discharge for selected southern African rivers. Many of the eastern sea-board rivers are strongly influenced by bed rock in the channel perimeter, and by a highly variable hydrological regime. This has resulted in characteristic channel forms, with an active channel incised into a larger macro-channel being a common feature of eastern seaboard rivers. Within the active channel inset channel benches commonly occur. This alluvial architecture is used to provide clues as to the types of flows necessary to meet the Reserve. Three river basins are considered : the Mkomazi, Mhlathuze and Olifants. The Mkomazi is a relatively un-impacted perennial eastern-sea board river and forms the research component of the study. The Mhlathuze and Olifants rivers are highly regulated systems and form the application component of the study. Utilising synthesised daily hydrological data, bed material data, cross-sectional surveys, hydraulic data and relevant bed material transport equations, channel form was related to dominant discharge and effective discharge in an attempt to identify the magnitude and frequency offlows that can be considered to be ' effective'. Results from the Mkomazi River indicate that no single effective discharge exists, but rather that there is a range of effective discharges in the 5-0.1% range on the 1-day daily flow duration curves that are responsible for the bulk (>80%) of the bed material transport. Only large floods (termed 'reset'discharges) with average return periods of around 20 years generate sufficient stream power and shear stress to mobilise the entire bed. The macro-channel is thus maintained by the large ' reset' flood events, and the active channel is maintained both by the range of effective discharges and the ' reset 'discharges. These are the geomorphologically 'effective' flows. Results from the Mhlathuze River have indicated that the Goedertrouw Dam has had a considerable impact on the downstream channel morphology and bed material transport capacity and consequently the effective and dominant discharges. It has been suggested that the Mhlathuze River is now adjusting its channel geometry in sympathy with the regulated flow environment. Under present-day conditions it has been demonstrated that the total bed material load has been reduced by up to three times, but there has also been a clear change in the way in which the load has been distributed around the duration curve. Under present-day conditions, over 90% of the total bed material load is transported by the top 5% of the flows, whereas under virgin flow conditions 90% of the total bed material load was transported by the top 20% of the flows. For the Olifants River there appears to be no relationship between the estimated bankfull discharge and any hydrological statistic. The effective discharge flow class is in the 5-0.01% range on the 1-day daily flow duration curve. It has also been pointed out that even the highest flows simulated for the Olifants River do not generate sufficient energy to mobilise the entire bed. It is useful to consider the Olifants River as being adapted to a highly variable flow regime. It is erroneous to think of one ' effective' discharge, but rather a range of effective discharges are of significance. It has been argued that strong bed rock control and a highly variable flow regime in many southern African rivers accounts for the channel architecture, and that there is a need to develop an ' indigenous knowledge' in the management of southern African fluvial systems
4
McGregor, Gillian Kathleen. "The geomorphological impacts of impoundments, with particular reference to tributary bar development on the Keiskamma River, Eastern Cape." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005510.
Full textAbstract:
The primary aim of this research was to develop and test a conceptual model of the geomorphological impacts of river regulation, based on a review of relevant international literature. It was motivated by the fact that there is very little local information on the topic, and it was intended that the model might provide a starting point for assessing the impact of impoundments on South African river systems. At present most research in South Africa on the impact of impoundments is undertaken from an ecological perspective. In order to manage our water resources sustainably it is necessary to have a better understanding of our river systems. South Africa is characterised by a variable climatic regime and, in order to supply water to the various user sectors of the nation, dams have to be larger than elsewhere in the world, to trap most of the mean annual runoff and provide a reliable water store (Alexander, 1985). South African dams have been designed to reduce the variability of a naturally variable regime. The impact of flow regulation in dryland rivers has been described as 'ecologically catastrophic at every level.' It is therefore hardly surprising that the impact of these dams on the natural functioning of rivers is substantial. The conceptual model showed that there are many responses to river impoundment, which are varied and complex, both in time and space. Responses or secondary impacts depended on the nature and degree of the primary impact or process alteration, on the sediment and flow regime of the river. High flows were affected in all cases and low flows were affected in most cases. The simplest form of change was Petts' (1979) concept of 'accommodation' of the regulated flow within the existing channel form. More complex responses occUrred where the channel perimeter was unstable, or where tributaries introduced fresh sediment loads. The river could adjust its long profile, cross sectional area and substrate composition by aggradation or degradation. The conceptual model was used in the Building Block Methodology to predict impoundment impacts at Instream Flow Requirement workshops on the Berg, Komati and Bivane rivers. It was also used in assessing the impact of the Sandile Dam on the Keiskamma river. Tributary junctions were identified as likely sites of change, and the morphology of bars at these junctions was investigated. Due to the number of variables affecting the sediment and flow regime in the system, and due to the fact that the primary impacts were not substantial, it was not possible to come to any decisive conclusions. It would seem that the dam is well located in the catchment, and, because the water is not heavily utilised, the secondary impacts are not great. The conceptual model was found to be a useful basic tool which might contribute to a better understanding of our river systems, and ultimately to improved sustainable resource management.
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Gazendam, Menno. "Incipient motion in cobble/boulder bed rivers." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50368.
Full textAbstract:
Thesis (MScEng)--University of Stellenbosch, 2005.<br>ENGLISH ABSTRACT: This study sets out to describe the incipient motion process in cobble/boulder bed rivers
in terms of the unit applied power approach. This objective has been met through the
collection of data on stone movement from a total of thirteen flood events observed in
two undisturbed rivers in the Western Cape, namely the Molenaars and Berg Rivers.
The data were plotted on the original modified Liu diagram for incipient motion and it
was found that the threshold of movement for the smaller stones did not conform with the
portion of the Liu diagram which represents fully turbulent flow (i.e.
where ~ gDs tv: = 0.12 for Re. >13). It was concluded that the only reason that could
explain this deviation is the fact that the original modified Liu diagram had been derived
for uniform particle size beds while the data of the Molenaars and Berg Rivers represent
non-uniform particle size beds. This was proved through re-deriving the y-axis function
of the original modified Liu diagram to include a factor that makes provision for the
roughness of a non-uniform particle size bed. It was found that the average absolute
roughness of the non-uniform particle size beds in the Molenaars and Berg Rivers is
reasonably well approximated by a value of k=da.
Design curves (in terms of the original modified Liu diagram parameters) for intensity of
motion were also produced. Although it is not possible to read off accurate percentages of
movement values directly from these curves, it should be possible to deduce reasonably
accurate values in practical situations.<br>AFRIKAANSE OPSOMMING: Die studie poog om die begin van beweging proses in klip/rotsbed riviere te beskryf in
terme van die eenheids aangewende drywing metode. Hierdie doel is bereik deur die
insameling van klipbewegingdata in 'n totaal van dertien vloedgebeurtenisse in twee
ongerepte riviere in die Wes-Kaap, naamlik die Molenaars en Bergriviere.
Die data was geplot op die oorspronklike aangepaste Liu diagram vir begin van beweging
en dit was gevind dat die grens van beweging vir die kleiner klippe nie ooreenstem met
die gedeelte van die Liu diagram wat volle turbulente vloei verteenwoordig nie
(waar ~ gDs tv; = 0.12 vir Re. >13). Daar was tot die gevolgtrekking gekom dat die
enigste rede wat die afwyking kan beskryf is die feit dat die oorspronklike aangepaste Liu
diagram afgelei was vir uniforme partikelgrootte beddens terwyl die data van die
Molenaars and Bergriviere nie-uniforme partikelgrootte beddens verteenwoordig. Dit was
bewys deur die heratleiding van die y-as funksie van die oorspronklike aangepaste Liu
diagram om 'n faktor in te sluit wat voorsiening maak vir die ruheid van 'n nie-uniforme
partikelgrootte bed. Dit was gevind dat die gemiddelde absolute ruheid van die nieuniforme
partikelgrootte beddens in die Molenaars en Bergriviere word redelik goed
benaderd met 'n waarde van k=ds4•
Ontwerpkurwes (in terme van die oorspronklike aangepaste Liu diagram parameters) vir
intensiteit van beweging was ook ontwikkel. Alhoewel dit nie moontlik is om baie
akkurate persentasies van beweging af te lees van die kurwes nie, is dit moontlik om
akkuraat genoeg waardes te verkry in praktiese situasies.
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Slaughter, Andrew Robert. "Modelling the relationship between flow and water quality in South African rivers." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006196.
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The National Water Act (Act 36 of 1998) provides for an ecological Reserve as the quantity (flow) and quality of water needed to protect aquatic ecosystems. While there are methods available to quantify the ecological Reserve in terms of flow, methods of linking flow to water quality are lacking. Therefore, the research presented in this thesis investigated various modelling techniques to estimate the effect of flow on water quality. The aims of the research presented in this thesis were: Aim 1: Can the relationship between flow and water quality be accurately represented by simple statistical models? Aim 2: Can relatively simple models accurately represent the relationship between flow and water quality? Aim 3: Can the effect of diffuse sources be omitted from a water quality model and still obtain realistic simulations, and if so under what conditions? Aim 4: Can models that solely use historical monitoring data, accurately represent the relationships between flow and water quality? In Chapter 3, simple Q-C regressions of flow and water quality were investigated using Department of Water Affairs (DWA) historical monitoring data. It was found that while flow versus salinity regressions gave good regression fits in many cases, the Q-C regression approach is limited. A mechanistic/statistical model that attempted to estimate the point and diffuse signatures of nutrients in response to flow was developed in Chapter 4 using DWA historical monitoring data. The model was verified as accurate in certain case studies using observed point loading information. In Chapter 5, statistical models that link land cover information to diffuse nutrient signatures in response to flow using DWA historical data were developed. While the model estimations are uncertain due to a lack of data, they do provide an estimation of the diffuse signature within catchments where there is flow and land cover information available. Chapter 6 investigates the extension of an existing mass-balance salinity model to estimate the effect of saline irrigation return flow on in-stream salinity. The model gave accurate salinity estimates for a low order stream with little or no irrigation within its catchment, and for a permanently flowing river within a catchment used extensively for irrigation. Chapter 7 investigated a modelling method to estimate the reaction coefficients involved in nitrification using only DWA historical monitoring data. Here, the model used flow information to estimate the residence time of nutrients within the studied river reaches. While the model obtained good estimations of nitrification for the data it was applied to, very few DWA data sets were suitable for the model. Chapter 8 investigated the ability of the in-stream model QUAL2K to estimate nutrient concentrations downstream of point and diffuse inputs of nutrients. It was found that the QUAL2K model can give accurate results in cases where point sources dominate the total nutrient inputs into a river. However, the QUAL2K simulations are too uncertain in cases where there are large diffuse source inputs of nutrients as the load of the diffuse inputs is difficult to measure in the field. This research highlights the problem of data scarcity in terms of temporal resolution as well as the range of constituents measured within DWA historical monitoring data for water quality. This thesis in addition argues that the approach of applying a number of models is preferable to applying one model to investigate the research aims, as particular models would be suited to particular circumstances, and the development of new models allowed the research aims of this thesis to be explored more thoroughly. It is also argued that simpler models that simulate a few key processes that explain the variation in observed data, are more suitable for implementing Integrated Water Resource Management (IWRM) than large comprehensive water quality models. From this research, it is clear that simple statistical models are not adequate for modelling the relationship between flow and water quality, however, relatively simple mechanistic models that simulate a limited number of processes and water quality variables, can provide accurate representations of this relationship. Under conditions where diffuse sources are not a major factor within a catchment, models that omit diffuse sources can obtain realistic simulations of the relationship between flow and water quality. Most of the models investigated in this thesis demonstrate that accurate simulations of the relationships between flow and water quality can be obtained using solely historical monitoring data.
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Uys, Amanda Cloete. "The invertebrates of temporary rivers in the Eastern Cape, South Africa." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004908.
Full textAbstract:
Temporary rivers in dryland regions are subject to highly variable and unpredictable rainfall and flow, and are considered unstable systems relative to perennial rivers of temperate zones. Little is known of the ecology of South Africa's temporary rivers, despite their abundance. The research presented focusses on the aquatic invertebrates inhabiting intermittently-flowing rivers in the 'arid corridor' of the Eastern Cape, South Africa. The major aims of the work were: to investigate which invertebrates inhabit these rivers, how the fauna is affected by environmental variability at various spatial and temporal scales, whether or not a characteristic fauna can be associated with these rivers or the hydrological phases which characterise them, and to establish to what extent faunal overlap occurs between different temporary rivers and between natural and modified temporary and perennial rivers. Research results indicate that the fauna of the Eastern Cape temporary rivers shows little structure at the scales of investigation, and that communities are generally non-equilibrial in character. The major forces shaping the biota are considered to be physical rather than biological, and the most important of these are: present and antecedent hydrological conditions and their duration; time of year; and biotope character, extent and heterogeneity. Three groups of fauna were identified as inhabitants of the temporary rivers: 'residents', 'facultative taxa' and 'opportunist colonists'. Taxa were tentatively allocated to these groups. Faunal resemblance was fairly high in Eastern Cape temporary rivers at the level of family, but not at more detailed taxonomic levels. A comparison between faunas of temporary and perennial rivers in different regions of South Africa illustrated the influence of geographical location on diversity. Within regions, however, there was no indication that perennial rivers were more diverse than intermittent rivers. The relatively high diversities in temporary rivers in this study are attributed at least in part to the heterogeneity in surface water conditions over time. A conceptual framework envisioning a continuum between perennial and temporary rivers is proposed as a basis for ongoing research into these rivers. A supporting terminology for the range of river flow types in South Africa is presented.
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Birkholz, Sharon Alice. "Human-river relationships in the Kat River catchment and the implications for integrated water resource management (IWRM) : an exploraratory study." Thesis, Rhodes University, 2009. http://eprints.ru.ac.za/1581/.
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Kriel, J. F. "Determining the elements of the operations management transformation model for the monitoring and breaching of the Great Brak River Mouth system." Thesis, Port Elizabeth Technikon, 2004. http://hdl.handle.net/10948/214.
Full textAbstract:
The prime challenge to those responsible for the management of South Africa’s estuaries is to maintain their viability in the face of ever increasing pressures. It is important that we learn to appreciate the value of estuaries and that we act wisely to manage them for sustainable use. Any operation must have the adequate resources to perform the duties and the correct processes must be followed. The purpose of this research is to determine whether the current inputs and processes needed for the monitoring and breaching of the Great Brak River Mouth system are sufficient to adhere to the output objectives of a healthy estuary together with safeguarding of properties. The research methodology for this study comprised the following steps: Firstly, a literature study was performed to identify the key elements of the operation management transformation model. Operations management deals with the output of any business, in other words the conversion of inputs to create certain outputs and they do this by a process of transformation. Secondly, extensive literature study was performed in order to access material regarding effective estuary and river mouth management. Thirdly, the current situation at Great Brak was assessed to determine whether the current inputs and processes are in place and if additional or altered inputs and processes are needed.
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Ewart-Smith, Justine L. "The relationship between periphyton, flow and nutrients in foothill rivers of the south-western Cape, South Africa." Doctoral thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/10490.
Full textAbstract:
Includes bibliographical references.<br>This thesis examines spatial and temporal patterns in periphyton community composition and biomass and the environmental factors responsible for shaping these communities in south-western Cape rivers. The study focused on two prennial foothill rivers in the south-western Cape: the Berg River, which is oligotrophic but has a large dam (The Berg Dam) situated in its upper reaches; and the Molenaars River, which has a natural flow regime but is moderately enriched by trout farm effluent. Two site on the Berg River (one upstream and one downstream of the Berg Dam) and two on the Molenaars River (one upstream and one downstream of the Du Toit's Kloof trout farm) were used to study temporal dynamics in periphyton communities over a 21-month period between September 2007 and May 2009.
Books on the topic "Rivers – South Africa"
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Rides in the mission field of South Africa: Between the Kei and Bashee rivers, Kaffraria : also, a visit to the missionary colleges of Lovedale and Heald Town, in British Kaffraria. Morgan and Scott, 1990.
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Lotriet, H. H. River discharge measurement in South African rivers: The development of improved measuring techniques. Water Research Commission, 1995.
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du Plessis, Anja. Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6.
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International, Conference on Fluvial Sedimentology (6th 1997 Cape Town South Africa). Catchment influences on the geomorphology and biota of the Sabie and Letaba Rivers in the Kruger National Park: Pre-conference field excursion, 6th International Conference on Fluvial Sedimentology, University of Cape Town, South Africa, 15 to 20 September, 1997. The Conference, 1997.
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Lupold, John S. Bridging deep south rivers: The life and legend of Horace King. University of Georgia Press, 2004.
Find full textBook chapters on the topic "Rivers – South Africa"
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Naidoo, Suvania. "The Nature of Acid Mine Drainage in the Vaal River System." In Acid Mine Drainage in South Africa. Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-44435-2_4.
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du Plessis, Anja. "Water Scarcity and Other Significant Challenges for South Africa." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_7.
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du Plessis, Anja. "South Africa’s Water Availability and Use." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_4.
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Martel, Patrick, Catherine Sutherland, Sylvia Hannan, and Fanele Magwaza. "Collaborative Spatial Expressions of Sustainability: River Rehabilitation Projects in Durban, South Africa." In Sustainable Urban Futures in Africa. Routledge, 2021. http://dx.doi.org/10.4324/9781003181484-9.
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Cavanagh, Edward. "Conclusion: Land Regimes and Property Rights on the Orange River." In Settler Colonialism and Land Rights in South Africa. Palgrave Macmillan UK, 2013. http://dx.doi.org/10.1057/9781137305770_6.
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du Plessis, Anja. "Primary Water Quality Challenges for South Africa and the Upper Vaal WMA." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_6.
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Dlamini, Vuyisile, Melanie Samson, and Chris Curtis. "Contested Understanding of River Health from Communities’ Perspective in the Lower Komati River in South Africa." In Socio-Ecological Systems and Decoloniality. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-15097-5_14.
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du Plessis, Anja. "Global Water Availability, Distribution and Use." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_1.
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du Plessis, Anja. "Conclusions and Evaluations." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_10.
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du Plessis, Anja. "Global Water Quality Challenges." In Freshwater Challenges of South Africa and its Upper Vaal River. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-49502-6_2.
Full textConference papers on the topic "Rivers – South Africa"
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Anderson, John Robert Beveridge. "Design and Development of the Msikaba and Mtentu River Bridges." In IABSE Conference, Kuala Lumpur 2018: Engineering the Developing World. International Association for Bridge and Structural Engineering (IABSE), 2018. http://dx.doi.org/10.2749/kualalumpur.2018.0497.
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<p>The story of the Msikaba and Mtentu River Bridges is a story about the Transkei Region in South Africa. The area’s unfenced rural landscape is considered unique and is characterised by steep gorges and rivers that run down to the Wild Coast. The civil engineers of the past avoided the area and the main highway connecting the ports of Durban and East London runs 200 km inland. This is now changing with the South African National Roads Agency’s SOC Ltd (SANRAL’s) procurement of the new N2 Wild Coast Road that will realign the highway within 30 km of the coast. The project includes two new crossings, one a 580 m span cable-stayed bridge, the other a 1.1 km long viaduct with a 260 m central balanced cantilever span, across the deepest gorges on the route. Their design and procurement is however driven not only by their physical environment but the need to create jobs, business opportunities for small local enterprises and community development projects that will leave a legacy and a long term economic benefit.</p>
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"Assessment of Seasonal Variation in Surface Water Quality of the Mooi and Vaal Rivers Network, South Africa." In International Conference on Advances in Science, Engineering, Technology and Natural Resources. International Academy of Engineers, 2016. http://dx.doi.org/10.15242/iae.iae1116408.
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Eze, Joy, Oluwarotimi Onakomaiya, Ademola Ogunrinde, et al. "Practical Experience in Rig Move and Workover Operations in an Amphibious Terrain: A Case Study of Escravos Beach Rig Move and Workover Operations." In SPE/AAPG Africa Energy and Technology Conference. SPE, 2016. http://dx.doi.org/10.2118/afrc-2582947-ms.
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ABSTRACT The exploration and production of oil and gas mostly occurs in remote locations, so as to minimize human exposure and Health Security Safety and Environment (HSSE) risks. Shell Companies in Nigeria is not any different having operated for over 50 years in Nigeria with the largest footprint of all the international oil and gas companies operating in the country spanning over land, swamp, shallow waters and offshore terrains. Shell Petroleum Development Company, the operator of a joint venture (the SPDC JV) between the government-owned Nigerian National Petroleum Corporation – NNPC (55% share), Shell (30%), Total E&P Nigeria Ltd (10%) and the ENI subsidiary Agip Oil Company Limited (5%) focuses mostly on onshore and shallow water oil and gas production in the Niger Delta with about 60+ producing oil and gas fields and a network of approximately 5,000 kilometers of oil and gas pipelines and flow lines spread across the Niger Delta. Escravos Beach is over 60km from the closest major city, Warri, a major oil and gas zone in the Niger Delta. It is bounded by the Escravos River to the East, Chevron canal to the North and the Atlantic Ocean to the South and is covered with predominantly mangrove forest especially along the creeks and consists of a number of natural and man-made waterways (rivers, creeks and canals). Unlike most other onshore operations, this location can only be accessed via the waterways; thus requiring the rig equipment and every other equipment to be channeled via the waterways and subsequently on land to arrive at the site. The amphibious nature of this operation requires a combination of onshore and swamp requirements with increased HSSE exposure, logistics requirement and cost. This paper aims to highlight the practical experience garnered in the rig move and workover operations of Rig XYZ which operated in the Escravos Beach region.
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Deane, Saul. "The Sandstone Squarehouses of Macarthur: The Ultra Vires Blockhouses of Sydney Basin’s Dispossession." In The 38th Annual Conference of the Society of Architectural Historians Australia and New Zealand. SAHANZ, 2022. http://dx.doi.org/10.55939/a3997pwac2.
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South of Campbelltown, wedged between Sydney’s two great rivers, where the Georges and the Nepean almost meet is Macarthur. In the early 1810s, to go beyond Campbelltown was to leave the authority of colonial Sydney - a colonial ultra vires frontier. Here are squarehouses that date from the mid-1810s, some were built during the height of Sydney’s frontier wars, before the 1816 Appin Massacre, which secured colonial control over all of Macarthur. These squarehouses are archaeologically intriguing as they are almost square, not large, have thick sandstone walls, some have ‘slot openings’ and others small openings. Were these squarehouses built with a defensive premise in mind, the openings for use as ‘gunloops’ as much as ventilation? If so they would be architectural evidence of the frontier wars. The suggestion is that these small squarehouses, often overlooked as just an outbuilding in the homestead aggregation, were among the first buildings built on a property. If built on contested land, its presence would have acted as notification of a land claim, while its physical structure provided a bolthole from which one could defend life and property - a private blockhouse. Blockhouses existed right across the British settler empire, with common standards constructed for defence in frontier areas from South Africa to New Zealand, Canada and the United States. So it should be no surprise to find them at the beginning of colonial NSW and yet it is, and this raises questions as to why this distinctive colonial structure is missing in Australia. The placement of these squarehouses and the prospect of their loops - their surveillance isovists over creeks and valleys, would provide historical insight into the colonial consolidation of these landscapes.
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PIETERSEN, JACOBUS P. J., and OCKERT J. GERICKE. "AREAL REDUCTION FACTORS FOR DESIGN RAINFALL ESTIMATION IN THE MODDER-RIET RIVER BASIN, SOUTH AFRICA." In RIVER BASIN MANAGEMENT 2019. WIT Press, 2019. http://dx.doi.org/10.2495/rbm190041.
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"Assessment of Microbial Quality of Surface Water Sources of Luvuvhu River Catchment, South Africa." In Nov. 27-28, 2017 South Africa. EARES, 2017. http://dx.doi.org/10.17758/eares.eap1117053.
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"Impact of Tea Processing Water Wastes on Phytoplankton Composition of Tshinane River, Limpopo Province." In Nov. 27-28, 2017 South Africa. EARES, 2017. http://dx.doi.org/10.17758/eares.eap1117054.
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GERICKE, OCKERT J. "DEVELOPMENT AND ASSESSMENT OF A SINGLE-EVENT DESIGN FLOOD ESTIMATION TOOL: CASE STUDY IN FOUR CLIMATOLOGICAL REGIONS OF SOUTH AFRICA." In RIVER BASIN MANAGEMENT 2019. WIT Press, 2019. http://dx.doi.org/10.2495/rbm190061.
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"Seasonal Metal Speciation in the Sabie River Catchment, Mpumalanga, South Africa." In Nov. 16-17, 2020 Johannesburg (SA). Eminent Association of Pioneers, 2020. http://dx.doi.org/10.17758/eares10.eap1120251.
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Nieuwoudt, W. L. "Pollution policies and market approaches in the Olifants River, South Africa." In WATER RESOURCES MANAGEMENT IV. WIT Press, 2007. http://dx.doi.org/10.2495/wrm070481.
Full textReports on the topic "Rivers – South Africa"
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Mpahlele, R. E., T. M. Malakalaka, and B. Hedden-Dunkhorst. Characteristics of smallholder irrigation farming in South Africa: a case study of the Arabie-Olifants River Irrigation Scheme. International Water Management Institute (IWMI), 2000. http://dx.doi.org/10.5337/2011.0040.
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