scholarly journals Investigating the interaction of waves and river discharge during compound flooding at Breede Estuary, South Africa

2021 ◽  
Author(s):  
Sunna Kupfer ◽  
Sara Santamaria-Aguilar ◽  
Lara van Niekerk ◽  
Melanie Lück-Vogel ◽  
Athanasios Vafeidis
Keyword(s):  
South Africa ◽  
South African ◽  
Hydrodynamic Model ◽  
River Discharge ◽  
Water Levels ◽  
Flood Events ◽  
Flood Magnitude ◽  
Compound Events ◽  
Flood Characteristics ◽  
Water Depths

Abstract. Recent studies have drawn special attention to the significant dependencies between flood drivers and the occurrence of compound flood events in coastal areas. This study investigates compound flooding from tides, river discharge (Q) and specifically waves using a hydrodynamic model at Breede Estuary, South Africa. We quantify vertical and horizontal differences in flood characteristics caused by driver interaction, and assess the contribution of waves. Therefore, we compare flood characteristics resulting from compound flood scenarios to those in which single drivers are omitted. We find that flood characteristics are more sensitive to Q than to waves, particularly when the latter only coincide with high spring tides. When interacting with Q, however, the contribution of waves is high, causing 10–12 % larger flood extents and 45–85 cm higher water depths, as waves caused backwater effects and raised water levels inside the lower reaches of the estuary. With higher wave intensity, the first flooding began up to 12 hours earlier. Our findings provide insights on compound flooding in terms of flood magnitude and timing at a South African estuary and demonstrate the need to account for the effects of compound events, including waves, in future flood impact assessments of open South African estuaries.

scholarly journals Comparison of West Balkan adult trout habitat predictions using a Pseudo-2D and a 2D hydrodynamic model

2016 ◽  
Vol 48 (6) ◽  
pp. 1697-1709 ◽  
Author(s):  
Christina Papadaki ◽  
Vasilis Bellos ◽  
Lazaros Ntoanidis ◽  
Elias Dimitriou
Keyword(s):  
Hydrodynamic Model ◽  
River Discharge ◽  
Environmental Flow ◽  
Two Dimensional ◽  
Habitat Models ◽  
One Dimensional ◽  
2D Flow ◽  
A Cell ◽  
The One ◽  
Water Depths

Abstract Hydraulic-habitat models combine the dynamic behavior of river discharge with geomorphological and ecological responses. In this study, they are used for estimating environmental flow requirements. We applied a Pseudo-two-dimensional (2D) model based on the one-dimensional (1D) HEC-RAS model and an in-house 2D (FLOW-R2D) hydrodynamic model to a section of river for several flows in respect of summer conditions of the study reach, and compared the results derived from the models in terms of water depths and velocities as well as habitat predictions in terms of weighted usable area (WUA). In general, 2D models are more promising in habitat studies since they quantify spatial variations and combinations of flow patterns important to stream flora and fauna in a higher detail than the 1D models. Relationships between WUA and discharge for the two models were examined, to compare the similarity as well as the magnitude of predictions over the modelled discharge range. The models predicted differences in the location of maxima and changes in variation of velocity and water depth. Finally, differences in spatial distribution (in terms of suitability indices and WUA) between the Pseudo-2D and the fully 2D modelling results can be considerable on a cell-by-cell basis.

Estimation of flood loss functions by activity sectors in the Pamplona metropolitan area in Spain by using insurance flood direct damage data

2020 ◽  
Author(s):  
Luis Mediero ◽  
Enrique Soriano ◽  
David Santillán ◽  
Luis Cueto-Felgueroso ◽  
Luis Garrote
Keyword(s):  
Metropolitan Area ◽  
Hydrodynamic Model ◽  
Loss Functions ◽  
Regional Government ◽  
Flow Depth ◽  
Flood Events ◽  
The Real ◽  
Direct Damage ◽  
Damage Data ◽  
Water Depths

<p>Flood risk assessment studies require information about direct damages that depend on several variables, such as water depth, water velocity, flood duration, activity sector and type of building, among others. However, loss functions are usually simplified through flow depth-direct damage curves. Direct flood damages driven by a given flood event can be estimated directly from such loss functions by using either known or estimated water depths.</p><p>In his study, flow depth-direct damage curves are estimated for a set of activity sectors in the Pamplona metropolitan area located in the northern part of Spain, within the activities of the EIT Climate-KIC SAFERPLACES project. A dataset containing all flood direct damages in the Pamplona metropolitan area in the period 1996-2018 were supplied by the Spanish ‘Consorcio de Compensación de Seguros’ (CSC), benefiting from the fact that CSC is the insurance company that covers all damages produced by natural hazards in Spain. Flood direct damages are classified by activity sectors and postal codes. In addition, observed streamflow data at a set of gauging sites in the Ulzama and Arga rivers were supplied by both the Ebro River Basin Authority and the Regional Government of Navarre. A set of seven flood events with both streamflow and direct damage data available were selected. Flood hydrographs in the Arga River at Pamplona were obtained with a temporal resolution of 15 minutes. The Regional Government of Navarre supplied the real flood extensions for a set of flood events. With such real flood extensions, the two-dimensional hydrodynamic IBER model was calibrated. Flood extensions and water depths with a spatial resolution of 1 m were estimated with the calibrated hydrodynamic model for the seven flood events. Combining the dataset of direct damages with standard flow depth-direct damage curves and with water depths simulated by the hydrodynamic model, flood depth-damage curves were estimated by municipalities and postal codes. Such curves were obtained for activity sectors, considering residential, commercial and industrial assets.</p><p><strong>Acknowledgments</strong></p><p>This study was supported by the project SAFERPLACES funded by the EIT Climate-KIC. The authors also acknowledge the ‘Consorcio de Compensación de Seguros’ for providing the flood direct damage dataset and the Regional Government of Navarre for providing the real flood extensions for given flood events.</p>

scholarly journals Bed-Sediment Transport Conditions along the Sagavanirktok River in Northern Alaska, USA

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 774
Author(s):  
Horacio Toniolo
Keyword(s):  
Sediment Transport ◽  
Water Levels ◽  
Bed Sediment ◽  
Flood Events ◽  
Expected Time ◽  
Resource Managers ◽  
Extensive Field ◽  
Northern Alaska ◽  
Intrinsic Error ◽  
Water Depths

This manuscript presents a study in predicting bed-sediment transport rates along the Sagavanirktok River in Alaska. Extensive field activities took place to accomplish this goal: four hydro-meteorological stations were installed in a 150 km reach along the river in summer 2015. During the same year, pits were excavated near the stations, and in subsequent summers, the pits were surveyed multiple times in conjunction with taking discharge measurements. Water slope was measured and bed sediment was characterized. Site-specific relationships between water levels and cross-section water depths were developed. Volume change between consecutive surveys was calculated, and main flood events between surveys were identified. Finally, the first bed-sediment transport equations valid for the Sagavanirktok River were developed. Considering the intrinsic error in sediment transport predictions, the agreement between predicted and measured sediment transport values is good. These equations could be used by resource managers when predicting the expected time for an excavated material site in the Sagavanirktok River to refill.

scholarly journals Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam

2016 ◽  
Vol 16 (4) ◽  
pp. 941-961 ◽  
Author(s):  
Heiko Apel ◽  
Oriol Martínez Trepat ◽  
Nguyen Nghia Hung ◽  
Do Thi Chinh ◽  
Bruno Merz ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Urban Areas ◽  
Flood Hazard ◽  
Hazard Analysis ◽  
Mekong Delta ◽  
Water Levels ◽  
Convective Precipitation ◽  
Processing Unit ◽  
Flood Events ◽  
Can Tho City

Abstract. Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either a fluvial or pluvial flood hazard, studies of a combined fluvial and pluvial flood hazard are hardly available. Thus this study aims to analyse a fluvial and a pluvial flood hazard individually, but also to develop a method for the analysis of a combined pluvial and fluvial flood hazard. This combined fluvial–pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as an example. In this tropical environment the annual monsoon triggered floods of the Mekong River, which can coincide with heavy local convective precipitation events, causing both fluvial and pluvial flooding at the same time. The fluvial flood hazard was estimated with a copula-based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. The pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data and a stochastic rainstorm generator. Inundation for all flood scenarios was simulated by a 2-dimensional hydrodynamic model implemented on a Graphics Processing Unit (GPU) for time-efficient flood propagation modelling. The combined fluvial–pluvial flood scenarios were derived by adding rainstorms to the fluvial flood events during the highest fluvial water levels. The probabilities of occurrence of the combined events were determined assuming independence of the two flood types and taking the seasonality and probability of coincidence into account. All hazards – fluvial, pluvial and combined – were accompanied by an uncertainty estimation taking into account the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by percentile maps. The results are critically discussed and their usage in flood risk management are outlined.

Reframing Xenophobia in South Africa as Colour-Blind: The Limits of the Afro Phobia Thesis

2020 ◽  
Vol 17 (3) ◽  
pp. 433-444
Author(s):  
Amanuel Isak Tewolde
Keyword(s):  
South Africa ◽  
South African ◽  
Analytical Framework ◽  
Conflict Theory ◽  
Black African ◽  
South Africans ◽  
Theoretical Perspectives ◽  
Online Newspaper ◽  
Close Proximity ◽  
Realistic Conflict Theory

Many scholars and South African politicians characterize the widespread anti-foreigner sentiment and violence in South Africa as dislike against migrants and refugees of African origin which they named ‘Afro-phobia’. Drawing on online newspaper reports and academic sources, this paper rejects the Afro-phobia thesis and argues that other non-African migrants such as Asians (Pakistanis, Indians, Bangladeshis and Chinese) are also on the receiving end of xenophobia in post-apartheid South Africa. I contend that any ‘outsider’ (White, Asian or Black African) who lives and trades in South African townships and informal settlements is scapegoated and attacked. I term this phenomenon ‘colour-blind xenophobia’. By proposing this analytical framework and integrating two theoretical perspectives — proximity-based ‘Realistic Conflict Theory (RCT)’ and Neocosmos’ exclusivist citizenship model — I contend that xenophobia in South Africa targets those who are in close proximity to disadvantaged Black South Africans and who are deemed outsiders (e.g., Asian, African even White residents and traders) and reject arguments that describe xenophobia in South Africa as targeting Black African refugees and migrants.

Region of Birth and Child Mortality among Black Migrants to South Africa: Is there a foreign-born advantage?

2016 ◽  
Vol 13 (3) ◽  
pp. 359-376 ◽  
Author(s):  
Tiffany L Green ◽  
Amos C Peters
Keyword(s):  
South Africa ◽  
South African ◽  
Child Mortality ◽  
Southern Africa ◽  
Strong Relationship ◽  
Developed Countries ◽  
Black Immigrants ◽  
Foreign Born ◽  
Region Of Origin ◽  
Child Deaths

Much of the existing evidence for the healthy immigrant advantage comes from developed countries. We investigate whether an immigrant health advantage exists in South Africa, an important emerging economy.  Using the 2001 South African Census, this study examines differences in child mortality between native-born South African and immigrant blacks.  We find that accounting for region of origin is critical: immigrants from southern Africa are more likely to experience higher lifetime child mortality compared to the native-born population.  Further, immigrants from outside of southern Africa are less likely than both groups to experience child deaths.  Finally, in contrast to patterns observed in developed countries, we detect a strong relationship between schooling and child mortality among black immigrants.

Some Reflections on Reparation in Post-Apartheid South Africa, using a Couple Therapy Intervention as a Microcosm of South African Society

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Andrea Hill ◽  
Sylvia Poss
Keyword(s):  
South Africa ◽  
South African ◽  
Couple Therapy ◽  
South African Society ◽  
Depressive Position ◽  
Central Hypothesis ◽  
Transference And Countertransference ◽  
Constructive Engagement ◽  
The Impact ◽  
Therapy Intervention

The paper addresses the question of reparation in post-apartheid South Africa. The central hypothesis of the paper is that in South Africa current traumas or losses, such as the 2008 xenophobic attacks, may activate a ‘shared unconscious phantasy’ of irreparable damage inflicted by apartheid on the collective psyche of the South African nation which could block constructive engagement and healing. A brief couple therapy intervention by a white therapist with a black couple is used as a ‘microcosm’ to explore this question. The impact of an extreme current loss, when earlier losses have been sustained, is explored. Additionally, the impact of racial difference on the transference and countertransference between the therapist and the couple is explored to illustrate factors complicating the productive grieving and working through of the depressive position towards reparation.

The Final ‘Thank You’

Derrida Today ◽  
2010 ◽  
Vol 3 (1) ◽  
pp. 21-36
Author(s):  
Grant Farred
Keyword(s):  
South Africa ◽  
South African ◽  
Jacques Derrida ◽  
Political Transition ◽  
The Other ◽  
World Cup ◽  
The Core ◽  
Nelson Mandela ◽  
Black President ◽  
The Moment

‘The Final “Thank You”’ uses the work of Jacques Derrida and Friedrich Nietzsche to think the occasion of the 1995 rugby World Cup, hosted by the newly democratic South Africa. This paper deploys Nietzsche's Zarathustra to critique how a figure such as Nelson Mandela is understood as a ‘Superman’ or an ‘Overhuman’ in the moment of political transition. The philosophical focus of the paper, however, turns on the ‘thank yous’ exchanged by the white South African rugby captain, François Pienaar, and the black president at the event of the Springbok victory. It is the value, and the proximity and negation, of the ‘thank yous’ – the relation of one to the other – that constitutes the core of the article. 1

Apartheid Aesthetics and Insignificant Art

2016 ◽  
Vol 33 (1) ◽  
pp. 45-69
Author(s):  
Stephanus Muller
Keyword(s):  
South Africa ◽  
Secondary School ◽  
South African ◽  
Cultural Production ◽  
Art Songs ◽  
Cultural Significance ◽  
European Culture ◽  
Small House ◽  
The Rich ◽  
Selection Of

Stephanus Le Roux Marais (1896−1979) lived in Graaff-Reinet, South Africa, for nearly a quarter of a century. He taught music at the local secondary school, composed most of his extended output of Afrikaans art songs, and painted a number of small landscapes in the garden of his small house, nestled in the bend of the Sunday’s River. Marais’s music earned him a position of cultural significance in the decades of Afrikaner dominance of South Africa. His best-known songs (“Heimwee,” “Kom dans, Klaradyn,” and “Oktobermaand”) earned him the local appellation of “the Afrikaans Schubert” and were famously sung all over the world by the soprano Mimi Coertse. The role his ouevre played in the construction of a so-called European culture in Africa is uncontested. Yet surprisingly little attention has been paid to the rich evocations of landscape encountered in Marais’s work. Contextualized by a selection of Marais’s paintings, this article glosses the index of landscape in this body of cultural production. The prevalence of landscape in Marais’s work and the range of its expression contribute novel perspectives to understanding colonial constructions of the twentieth-century South African landscape. Like the vast, empty, and ancient landscape of the Karoo, where Marais lived during the last decades of his life, his music assumes specificity not through efforts to prioritize individual expression, but through the distinct absence of such efforts. Listening for landscape in Marais’s songs, one encounters the embrace of generic musical conventions as a condition for the construction of a particular national identity. Colonial white landscape, Marais’s work seems to suggest, is deprived of a compelling musical aesthetic by its very embrace and desired possession of that landscape.

ROLE OF LIBRARIANS IN TEACHING INFORMATION LITERACY IN ZIMBABWEAN AND SOUTH AFRICAN UNIVERSITIES: A COMPARATIVE STUDY

Mousaion ◽  
2016 ◽  
Vol 33 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Tinashe Mugwisi
Keyword(s):  
South Africa ◽  
South African ◽  
Information Literacy ◽  
Ethical Issues ◽  
University Libraries ◽  
Information And Communications Technologies ◽  
Communications Technologies ◽  
Information Skills ◽  
The University

Information and communications technologies (ICTs) and the Internet have to a large extent influenced the way information is made available, published and accessed. More information is being produced too frequently and information users now require certain skills to sift through this multitude in order to identify what is appropriate for their purposes. Computer and information skills have become a necessity for all academic programmes. As libraries subscribe to databases and other peer-reviewed content (print and electronic), it is important that users are also made aware of such sources and their importance. The purpose of this study was to examine the teaching of information literacy (IL) in universities in Zimbabwe and South Africa, and the role played by librarians in creating information literate graduates. This was done by examining whether such IL programmes were prioritised, their content and how frequently they were reviewed. An electronic questionnaire was distributed to 12 university libraries in Zimbabwe and 21 in South Africa. A total of 25 questionnaires were returned. The findings revealed that IL was being taught in universities library and non-library staff, was compulsory and contributed to the term mark in some institutions. The study also revealed that 44 per cent of the total respondents indicated that the libraries were collaborating with departments and faculty in implementing IL programmes in universities. The study recommends that IL should be an integral part of the university programmes in order to promote the use of databases and to guide students on ethical issues of information use.

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