The Bac Hung Hai zone is the greatest basin in the Red River Delta in Vietnam and also one of the most densely populated regions of the planet. It is mainly a rural region and its economy is dominated by agriculture. In the context of frequent and larger floods in the Bac Hung Hai zone, causing deep socio-economical consequences, the focus of this study is to establish cartography of the high risk areas for flooding in the Bac Hung Hai region using remote sensing and GIS to assist land management. The preparation of a map describing land management in this region is more complicated because parcels for farming are very small and not homogeneous. A consistent and precise map of land use is essential for studies of flooding. The secondary objective is to improve the land use map. To this effect, a classification has been applied to the combination of the spectral bands and textures (TM and ETM[indice supérieur +]) of Landsat and a radar image (ERS). The addition of this information to the spectral bands increases the accuracy of classification by 1% to 4%, according to the dates selected. Additionally, in the study zone where there are few days without clouds, a problem related to the optical satellite image is the cloud cover. Then, the use of radar images will provide ground information for areas hidden by clouds where spectral images are not sufficient. To reach these goals, we have determined the main biophysical considerations that influence flooding. Then, these considerations have been combined in a multi-criteria analysis to evaluate the risks of flooding in the entire basin area. The results show that high to very high risks affect 47% of the area studied and that the south-east region, center, and north-east present the greatest risk.

Thesis (MA)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The petroleum industry concern itself with natural resource extracting activities which are highly sensitive for contributing to environmental degradation by oil spills or gas flaring. A large proportion of the world’s oil and gas reserves is located in developing countries where the presence of multinational oil corporations (MNOCs) is high as host countries often lack the infrastructure needed or are financially unable to conduct extracting operations on their own. The Niger Delta in southern Nigeria has one of the largest oil reserves in Africa and is one of the world’s leading oil exporters. MNOCs like Shell, Chevron, Total, ExxonMobil and Statoil are some of the firms present in the Niger Delta region. The oil-rich area in the developing country poses high levels of political risk for the MNOCs. Local grievances, paired with environmental degradation and human rights violations by the oil companies, have led to a tense relationship between the local stakeholders and the MNOCs, with so-called petro-violence at the center of the oil conflict. Frequently, oil installations are sabotaged and crude oil is stolen, causing major financial losses for the firms, and armed attacks on oil facilities and kidnapping of MNOCs’ staff constitute the majority of political risks facing MNOCs operating in the Niger Delta. This study investigates how MNOCs can successfully manage such political risks, providing a business advantage in a challenging business environment. By addressing the companys’ own behaviour, the research analyses if social engagement through corporate social responsibility (CSR) can mitigate political risk in the Niger Delta. The study looks at two different MNOCs operating in the Niger delta, Shell and Statoil, and scrutinises their methods of implementation of their CSR initiatives. The difference in approaches to CSR is elucidated where Shell claims it has repositioned its approach from a top-down angle during the first years of conducting CSR projects, to a more stakeholder-oriented approach. Yet, their approach is still found to carry elements of the previous top-down approach, and has not resulted in satisfactory performance in relation to stated goals. Statoil undertakes a stakeholder-oriented bottom-up approach, executed with a high level of commitment. The stated CSR goals have to a great extent been met. By assessing the two companies’ CSR strategies in relation to the frequency of political risks experienced by each MNOC, the study finds that CSR has the potential to mitigate political risk depending on the approach to implementation, and could serve as a political risk management strategy. / AFRIKAANSE OPSOMMING: Die brandstofbedryf is betrokke by die ontginning van natuurlike hulpbronne, ’n aktiwiteit wat hoogs sensitief is vir sy bydrae tot omgewingsbesoedeling as gevolg van storting van olie en opvlamming van gas. ’n Baie groot deel van die wêreld se olie en gas reserwes word aangetref in ontwikkelende lande. Die teenwoordigheid van Multinasionale Olie Korporasies (MNOKs) in hierdie lande is groot omdat daar gewoonlik ’n gebrek aan toepaslike infrastruktuur is en die lande ook nie finansieel in staat mag wees om die ontginning op hulle eie te doen nie. Die Niger Delta in die Suide van Nigerië beskik oor een van die grootste olie reserwes in Afrika en is een van die voorste olie uitvoerders in die wêreld. Shell, Chevron, Total, ExxonMobil en Statoil is van die bekende MNOK wat ontginning doen in die Niger Delta gebied. Die olieryke gebiede in ’n ontwikkelende land kan groot politieke risiko vir die MNOKs inhou. Plaaslike griewe gekoppel aan omgewings besoedeling en menseregte skendings deur die oliemaatskappye het gelei tot ’n gespanne verhouding tussen hulle en die plaaslike belange groepe, en sogenaamde “petrogeweld” staan sentraal hierin. Heel gereeld word olie-installasies gesaboteer en ru-olie word gesteel, wat natuurlik groot finansiële verliese die firmas inhou. Daarby word gewapende aanvalle op die olie-installasies uitgevoer en van die MNOKs se personeel ontvoer. Al hierdie dinge vorm die groot politieke risiko’s wat die MNOKs in die Niger Delta in die gesig staar. Hierdie studie ondersoek hoe die MNOKs met welslae hierdie politieke risiko’s kan teenwerk om vir hulle ’n suksesvolle besigheid te vestig in ’n baie mededingende bedryfsomgewing. Deur te kyk na die maatskappy se eie gedrag, sal die navorsing analiseer of gemeenskapsbetrokkenheid deur korporatiewe sosiale verantwoordelikheid (KSV) die politieke risiko in die Niger Delta kan temper. Die studie kyk na twee verskillende MNOK wat in die gebied bedryf word, Shell en Statoil, en kyk noukeurig na die manier waarop hulle KSV inisiatiewe toegepas word. Die verskil in benadering tot die probleem word toegelig deur die feit dat Shell beweer dat hulle ’n bo-na-onder benadering in die beginjare van KSV projekte verander het na ’n beleid waar meer na die betrokkenheid van belangegroepe gekyk word. Tog word gevind dat daar nog oorblyfsels is van die bo-na-onder benadering en dat doelwitte wat gestel is nie bevredigend bereik is nie. Statoil daarenteen. Implementeer ’n onder-na-bo benadering met betrokkenheid van belangegroepe en ’n hoë vlak van toewyding deur die maatskappy. Die gestelde KSV doelwitte is grootliks behaal. Deur te kyk na die twee maatskappye se ervaring van politieke risiko in verhouding met hulle KSV strategieë bevind hierdie studie dat KSV wel die potensiaal het om, as dit suksesvol toegepas word, politieke risiko te temper en dus kan die as ’n strategie om sodanige risiko te bestuur.

Thesis (MEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Tana River, the largest river in Kenya, is an important habit that supports numerous types of life, which creates an attractive environment. Occasionally loss of life and damage to property are experienced during floods. Upstream development of hydropower generation dams without consideration of downstream impacts is well documented in literature and the aftermaths are being well exhibited currently. The aim of the thesis is to investigate and identify factors that affect the flood levels in the Tana River Delta by using a two dimensional model and eventually drawing up a velocity- water depth interaction hazard classification map. Reviews of the literature clearly established that the floods in the delta are not generated by internal rainfall only but also operation of upstream dams accounting for 95% of the flood levels. Consequently, investigations of the impacts of dams have on flow regime were carried out. Probabilistic analysis revealed that post dam seasonal patterns has not been impacted but the magnitude of flood peaks has generally declined due to the attenuation of small peaks. However, large/flash floods (10 year Annual Recurrence Interval (ARI) spill at the dams causing major flooding downstream. Further probabilistic analysis on river discharges and sea water level was carried out to determine various ARI peaks. This incorporated climate change based on the 4th IPCC report. A two-dimensional hydrodynamic model was set up and calibrated with recorded discharges and theoretically derived parameters. Impacts of extreme tidal levels were investigated on the water levels and other factors limiting flood propagation. Finally, the model was used to simulate the 2, 50 and 100 year ARI inclusive of climate change floods and, based on Australian guidelines, flood lines and hazard maps were drawn. The results show that high tides elevate water levels in the delta in combination with the bottleneck effect at the rechanneled canal. The road crossing through the delta has inadequate bridges to convey the floods. The derived flood maps drawn (Figure 6-4) highlight that settlements in the lower delta are located within the 2 year ARI flood lines and that the extent of flooding is similar or less so in 50 and 100 year ARI flood peaks simulated. The model predicted the velocity and water depths with sufficient accuracy and recommendations are made that the study area should be extended upstream, and more field data should be collected to aid in calibration and that land use should be incorporated in flood map classification. In conclusion, the thesis has identified the flood hotspots and factors governing floods. These findings could assist in decision making by various agencies proposing flood mitigation or advocating post dam flooding scenarios. / AFRIKAANSE OPSOMMING: Die Tanarivier is die grootste rivier in Kenia en ’n belangrike habitat vir verskeie tipes diere en plante wat ‘n aantreklike omgewing skep.Verlies aan lewens en skade aan eiendom vind egter somtyds tydens oorstromings plaas. Die bou van damme vir die ontwikkeling van hidrokrag hoër op in die rivier sonder om die impak laer af in ag te neem, asook die gevolge daarvan, word dikwels in die lireratuur beskryf. Die doel met hierdie tesis is om die faktore wat die vloedhoogtes in die Tanarivier beïnvloed met die gebruik van ’n twee-dimensionele hidrodinamiese model te ondersoek en te identifiseer en om dan ’n gevaarsonekaart te teken wat die interaksie tussen waterspoed en -diepte toon. Die oorsig van die literatuur het getoon dat die oorstromings in die delta nie die gevolg is van reën in die binneland nie, maar dat die damme hoër op in die rivier verantwoordelik is vir 95% van die oorstromings. Dus is die impak van die damme op oorstromings ondersoek. Waarskynlikheidsontleding het oor die algemeen getoon dat die na-dam seisoenale vloeipatrone nie beinvloed is nie, maar dat veral die kleiner vloedpieke in die algemeen afgeneem het as gevolg van vloedattenuasie deur die damme. Groter en frats oorstromings (>1:10 ARI) veroorsaak egter steeds dat die damme oorloop en lei tot ernstige oorstromings. Die verdere waarskynlikheidsontleding van riviervloei en die seewatervlak is uitgevoer om die verskillende Jaarlikse Herhaling Periode (JHP) vlakke vas te stel. Dit het klimaatsverandering gegrond op die 4de IPCC verslag ingesluit. ʼn Twee dimensionele hidrodinamiese model is opgestel en gekalibreer teen waargenome vloei en teoreties-afgeleide parameters is gekalibreer. Die impak van uiterste getyvlakke asook faktore wat die oorstromings beperk is ondersoek. Die model is toe gebruik om die 2, 50 en 100 JHP vloedoorstromings te simuleer en vloedlyne en gevaarkaarte is volgens die Australiese riglyne geteken. Die resultate toon dat hooggety die watervlak in die delta laat styg veral in kombinasie met die bottelnek effek van die nuwe kanaal. Daar is te min brûe op die pad wat die delta deurkruis, om die vloede se vloei deur te laat Die kaarte wat geteken is toon dat daar nedersettings in die laer delta binne die 2 JHP jaar vloedarea is en dat die omvang van oorstromings dieselfde of laer is as die 50 en 100 JHP jaar vloedpieke wat gesimuleer is. Die model kan gebruik word om die vloeispoed en waterdieptes redelik akkuraat te voorspel en die volgende aanbevelings word gemaak. Toestande hoër op teen die rivier moet ondersoek word, meer data wat gedurende kalibrasie gebruik kan word moet versamel word en grondgebruik moet in die kaartklassifikasie ingesluit word. Ten slotte is die gevaarpunte vir oorstromings en die faktore wat oorstromings veroorsaak aangetoon. Hierdie bevindinge kan van nut wees as besluite geneem moet word veral wat betref die voorkoming van oorstromings nadat damme gebou is.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

published_or_final_version / Business Administration / Master / Master of Business Administration

published_or_final_version / abstract / toc / China Area Studies / Master / Master of Arts

published_or_final_version / abstract / Geography / Master / Master of Philosophy

published_or_final_version / Transport Policy and Planning / Master / Master of Arts

The Wax Lake Delta (WLD) is a sandy, modern river delta prograding rapidly into Atchafalaya Bay. This dissertation uses field data to improve the understanding of channel kinematics that dictate river delta geometry and stratigraphy, while providing a framework for coastal restoration efforts. The studies presented here show that the distributary channel network of the WLD is erosional. In the first study, analyses of the feeder channel to the WLD and the channel network within the sub-aerially emergent delta show that the channel bed has incised into the consolidated muds that act as bedrock. The large (>62%) fraction of bedrock exposure found in multi-beam surveys is related to the under-saturation of suspended sand measured during the flood of 2009. The second study concerns the delta front beyond the emergent delta Distributary channels extend 2 – 6 km into the delta front. Four bathymetric surveys of one bifurcating distributary channel – Gadwall Pass – show that the majority of bed aggradation occurs during floods, but the majority of channel extension of each bifurcate channel occurs during low river discharge. In the third study, field measurements of fluid flow during a tidal cycle indicate that tidal augmentation of during periods of low river discharge is responsible for channel extension during low river discharges. Flow direction measured from streaklines present in aerial photomosaics is combined with bathymetric evolution data to quantify spatial velocity changes on the delta front. These data show that flow spreading is insufficient to prevent acceleration at channel margins, providing an explanation for observed erosion. Flow divergence is limited on the delta front by the proximity of neighboring channels, even though they are separated by 10-30 channel widths. The associated convergence of flow in inter-distributary bays occurs along “drainage troughs”. These channel-forms collect flow that has been dispensed from distributary channel network. Finally, ambient currents in Atchafalaya Bay (0.06 – 0.2 m/s) caused by tides and the proximity to the neighboring Atchafalaya Delta appear to alter flow patterns on the delta foreset, and are responsible for channel curvature on the delta front. / text