On the Natural and Anthropogenic Drivers of the Senegalese (West Africa) Low Coast Evolution: Saint Louis Beach 2016 COASTVAR Experiment and 3D Modeling of Short Term Coastal Protection Measures

2020 ◽  
Vol 95 (sp1) ◽  
pp. 583
Author(s):  
A. Ndour ◽  
K. Ba ◽  
A. Almar ◽  
P. Almeida ◽  
M. Sall ◽  
...  
2014 ◽  
Vol 1 (34) ◽  
pp. 5 ◽  
Author(s):  
Theide Wöffler ◽  
Holger Schüttrumpf ◽  
Roger Häußling ◽  
Hilmar Von Eynatten ◽  
Arne Arns ◽  
...  

2008 ◽  
Author(s):  
Antony Price ◽  
Patrick Turpin ◽  
Michel Erbetta ◽  
Don Watts ◽  
Graeme Cairns

2015 ◽  
Vol 19 (3) ◽  
pp. 281-294 ◽  
Author(s):  
Ali Masria ◽  
Moheb Iskander ◽  
Abdelazim Negm

2020 ◽  
Vol 8 (4) ◽  
pp. 247 ◽  
Author(s):  
Mireille Escudero ◽  
Edgar Mendoza ◽  
Rodolfo Silva

In the last decade, innovative beach nourishment strategies have been developed, driven by the increased worldwide interest in environmentally friendly coastal protection measures. In this context, the massive nourishment project of the Netherlands, known as Sand Engine, begun in 2011, has been hailed as a successful means of beach protection. Continuous monitoring, field campaigns, and numerical modeling have shown that the great volume of sand deployed is gradually transported by the waves and currents along the coastline, avoiding the need for repeated invasive, small scale beach replenishments. A very small, bell-shaped Sand Engine was designed to protect the beachfront at a tourist resort near Puerto Morelos, Mexico. To estimate the morphological response of the beach and the functioning of the micro Sand Engine as a sand reservoir, XBeach numerical modelling was applied to the project. The micro Sand Engine is seen to be a sustainable and eco-friendly coastal protection measure, especially applicable when a large nourishment project is not viable. Maintenance work for the nourishment is cost and time effective, and any negative impacts to sensitive ecosystems nearby can be detected and controlled quickly.


Author(s):  
Odile Goerg

During colonial times, cities, whether ancient or modern, underwent enormous changes. Urban life can be seen as a story of continuity and change, of invention and adaptation. Multiple constraints were imposed by colonial rule (e.g., spatial framework and mobility regulations, sanitation policy, control of the use of time, and so on), but new opportunities also presented themselves, professionally or otherwise, for example, in terms of defining one’s identity. Older inhabitants, as well as newcomers flowing to the main cities, especially from the 1930s, formed the foundation for a new, urbanized society. To frame the study of “urban life” within the political context of “French West Africa” presupposes both that there is something specific to the cities in the eight colonies, which, eventually, constituted FWA (French West Africa) plus the Togo mandate, and that there is something common to all these western African cities under French colonial rule. None of this is really valid. There are as many similarities with urban life in British West Africa as there are differences between the cities. When discussing urban life within the French colonial cities, one can mention the disproportionate allocation of space and resources aimed at satisfying the needs of the colonizers, or the will to rule and control all aspects of urban life. What is common between more than one-thousand-year-old Tombouctou and Conakry, a little more than a century old? Between Saint-Louis du Sénégal, which served as a main entrepôt for international trade from the mid-17th century, and Lomé, with Bè villages in the hinterland, founded by local merchants in the 1880s to escape British customs taxes? But despite the shortcomings of this methodological framework, one can form a general idea of urban life in colonial cities, provided that it be nuanced and contextualized, always bearing in mind a broader comparative framework encompassing British and French policies elsewhere in the empires. Urban life can be understood as the ways city dwellers organize their everyday activities: work, social interactions, but also leisure activities or political involvement. All these aspects changed over time, as city dwellers asserted themselves and, gradually, obtained more legal rights.


2020 ◽  
Author(s):  
Lutfian Rusdi Daryono ◽  
Kazunori Nakashima ◽  
Satoru Kawasaki ◽  
Koichi Suzuki ◽  
Anastasia Dewi Titisari ◽  
...  

<p>Erosion prone sandy beaches are frequently covered by cement and mortar to preserve the coastal zone, but the conventional approach has an adverse impact on the environment, altering the coastal landscape and processes unfavorably. The term “beachrock” refers to cemented coastal sediments through a long-term formation of CaCO<sub>3</sub> cement, and which is an important feature in many tropical coastlines as it appears to have a substantial anchoring effect against wave effects and erodibility. Therefore, the objective of this study is to evaluate the feasibility in progressing the formation of artificial beachrocks using natural materials (e.g., microbes, sand, shell, pieces of coral, and seaweed etc.) within a short-term, and to introduce the method as a novel candidate for coastal protection. In this study, both resistivity survey and multi analysis seismic wave (MASW) survey along the same lines were performed at first to elucidate the subsurface structure of existing beachrocks in the Southeast Yogyakarta coastal area (Indonesia), followed by the laboratory analysis, which is aimed understand the basics in the formation mechanism. Peloidal micrite cement, the cement comprised of aragonite needles, micritized granules and the cover of micritic were observed in natural beachrocks. Mimicking the mechanism, an attempt has been undertaken to develop artificial beachrocks in the laboratory via microbial induced carbonate precipitation (MICP). Finally, the physical and mechanical properties were well compared between the artificially formed beachrocks and natural beachrocks collected from the survey lines. The results suggest that the artificial deposits treated for 14 days under optimum conditions, achieved a peak unconfined compressive strength of around 6 MPa similar to that of weak-consolidated natural beachrock. The comparison further reveals that the variables such as porosity, Vp, Vs, and strength are primarily rely on the precipitated morphology of the crystals.</p>


2006 ◽  
Vol 43 (3) ◽  
pp. 313-320 ◽  
Author(s):  
A. Bilgo ◽  
D. Masse ◽  
S. Sall ◽  
G. Serpantié ◽  
J-L. Chotte ◽  
...  

2001 ◽  
Vol 28 (2) ◽  
pp. 393 ◽  
Author(s):  
LUCIANA SLOMP ESTEVES ◽  
ISAAC RODRIGUES DOS SANTOS

Although there is still a discussion about the extent of erosion along the Rio Grande do Sul shoreline, some places are recognized as intensely eroded, such as Jardim do Éden beach, Conceição Lighthouse, and Hermenegildo. This study evaluates the economic impacts of erosion in Hermenegildo based on the costs of coastal protection, destruction of structures during storms, and depreciation of beachfront property values. The study area consists in the 2-km long urbanized shore of Hermenegildo, a beach village located in the southernmost littoral of Brazil, 12 km north of the Uruguayan border. Erosion has threatened beachfront development during storms, resulting in a heavily armored shoreline. Quarrystone revetments (rip rap) and/or seawalls are the most common structures. A strong storm struck this coast in 16 April 1999 destructing 22 houses, all concrete structures, half of the quarrystone revetments, and 80% of the timber seawalls. After that storm, similar structures were built to protect beachfront properties. According to interviews conducted with property owners, average protection costs were estimated in U$ 2,203/property or U$79,308/km. Extrapolating the average costs for the 72 protected properties, total expenses in coastal defense is estimated in U$ 158,616. Considering a storm with same intensity and destruction power reaching the coast of Hermenegildo, the expected damage in land loss, destruction of houses and structures would be in the order of U$ 394,000. Analysis of the real estate sales in the last three years indicates a depreciation of 50-80% in beachfront property values while properties located further inland had a depreciation of 10%. Beach erosion has impacted the local economy and will continue to do so until the problem is effectively addressed. As the values at risk in Hermenegildo are relatively lower than usual coastal protection measures, probably relocation of structures or alternative techniques might be the best management option.


2021 ◽  
Vol 15 (4) ◽  
pp. 59-70
Author(s):  
V. Kyyak ◽  
◽  
T. Mykitchak ◽  
O. Reshetylo ◽  
◽  
...  

Introduction. The highlands of the Ukrainian Carpathians belong to the territories with the highest concentration of rare species and coenotic diversity in Ukraine. Due to highland ecosystem transformation, a large number of populations and communities of rare species are under the threat of degradation and elimination. Climate change. At present, effective growth and development of plants begins 2–3 weeks earlier compared to the 1980–90s. Sharp seasonal distribution of precipitation causes negative changes in the highland water-body hydrology regime affecting freshwater populations of plankton crustaceans and amphibians. Demutative successions. During the first 10–20 years of the succession its influence on the structure and vitality of the majority of rare species populations is mostly positive, but 30–40 year-long demutations usually cause negative dynamics. Overgro­wing results in the simplification of spatial structure and fragmentation, as well as decreasing of population density, disappearing of rare species from the community structure. Active protection measures should be locally implemented in protected territories: traditional type of grazing, mowing, and shrub or tree cutting in the cases of protection of extremely rare phytocoenoses and populations. Anthropogenic impact. Intensive recreation pressure causes digressive changes in numerous communities, which are located along the popular tourist paths to the glacial lakes, mountain summits etc. Unfortunately, the systematic violation of the protection regime in the highland zone of the Ukrainian Carpathians is obvious nowadays. Gathering medicinal and ornamental species poses a serious threat. Uncontrolled increase in the number of recreants in the highland areas for the last 5 years has destroyed its aquatic ecosystems more than in the previous 30–40 years. Usage of vehicles for recreation purposes (4×4, quads and motorcycles) refers to significant destructive factors for highland ecosystems. Protection measures. Population conservation and revival of communities is usually possible under the condition of moderate and short-term anthropogenic pressure. The visiting regime of the most popular highland sites must be put under control immediately, while mass ascensions must be completely forbidden.


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