Genesis and Evolution of A Beach-Ridge Plain Reflecting Relative Sea-Level Rise: A Case Study From Trab El Makhadha Gulf of Gabes, Southeastern Tunisia

Gzam, Maher; Elmejdoub, Noureddine; Boussetta, Soumaya; Jedoui, Younes

doi:10.2110/jsr.2014.21

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…The North African arid coasts are characterized by mixed siliciclasticcarbonate sediments from the tertiary and quaternary (i.e. Pleistocene and Tyrrhenian) outcrops [40][41][42] . The low- www.nature.com/scientificreports/ lying plains are filled by alluvial washes and rivers deposits.…”

Section: Origins and Implications Of The Coastal Vulnerabilitymentioning

confidence: 99%

Alarming coastal vulnerability of the deltaic and sandy beaches of North Africa

Hzami

Heggy

Amrouni

et al. 2021

Sci Rep

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The arid coasts of North Africa, extending over 4633 km from the Gulf of Tunis to the Nile Delta, are undergoing pronounced shoreline retreats and coastal floodings that are reported as a consequence of the ongoing sea level rise resulting from global warming. Of particular interest are the abnormal shoreline dynamics for deltaic and sandy beaches, which are severely impacted by abrupt decadal variabilities in both climatic and anthropogenic drivers resulting in their increased vulnerability to disturbances from coastal hazards. Unfortunately, the evolution, distribution and impacts of these drivers remain largely unquantified, let alone understood, for these extensive arid coasts that harbor the major portion of North Africa’s population as well as unique and fragile marine ecosystems. To address this deficiency, we use GIS-based multi-criteria approaches combined with analytic hierarchy process to map the Coastal Vulnerability Index and the Socioeconomic Vulnerability Index along these coasts to investigate the amplitude and extent of shoreline deterioration resulting from sudden fluctuations in sediment transport to the coastline. We use the western bay of the Gulf of Tunis, the coasts of Tripoli and the Nile Delta as three validation sites for our vulnerability assessment. The statistical Integrated Coastal Vulnerability Index map reveals that 47% of arid North African coasts are characterized by high to very high vulnerability. In particular, we observe that the densely populated deltaic coasts in both Tunisia and Egypt are 70% more vulnerable than any others coast in the eastern Mediterranean Basin. These abnormally high-vulnerability extensive areas are also correlated with significant deterioration of coastal aquifers and hence in crop production, compromising local food security and resulting in increasing outflow migration trends. Both Tunisia and Egypt observed dramatic increases in the net population outflow migration by respectively 62% and 248% between 2000 and 2016, mostly from coastal areas. Our source analysis of the amplitude and extent of these high coastal vulnerabilities suggests that they result from the anthropogenic drivers of damming and rapid urban growth over the last few decades rather than the effects of global warming.

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Section: Origins and Implications Of The Coastal Vulnerabilitymentioning

confidence: 99%

Alarming coastal vulnerability of the deltaic and sandy beaches of North Africa

Hzami

Heggy

Amrouni

et al. 2021

Sci Rep

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“…The considerable losses of dunes and beaches around urbanized areas compromise safety against ooding (Bouchahma and Yan, 2014). Additional complications of littoral disturbance are ampli ed by the construction of harbor infrastructures which are threatened by the silting up problem (Paskoff, 1994;Magherbi, 1995;Ben Amor et al, 2003;Bejaoui et al, 2004;Bardi, 2010;Gzam et al, 2013a;Gzam et al, 2014). Therein it's necessary to evaluate the coastal sensitivity using the index approach in order to recommend the adequate criteria's for use in littoral planning.…”

Section: Introductionmentioning

confidence: 99%

“…The CSI scores range from 14 to 34, with a mean of 22.7 (Figure5; median is 22). Thus the mid-range(21)(22)(23) was considered to be moderate sensitivity zones. High sensitivity values extend from 24 to 26.…”

mentioning

confidence: 99%

Assessment of the Coastal Sensitivity Using the CS Index in the Gulf of Gabes Tunisia; Southern Mediterranean Coast

Gzam

Mansouri

Gargouri

et al. 2021

Preprint

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Assessment of the coastal degradation using the coastal sensitivity index (CSI) in the microtidal environment (Gulf of Gabes, Tunisia) shows that 78.6% of the coast is under low to moderate sensitivity. Moderate sensitivity class includes the sheltered zones and the stable sea cliffs. The highest sensitivity was recorded in sandy beaches (12.7%) where the drift actions amplify littoral fragility and flood risk.The coastal sensitivity index (CSI) is resulted from the combination of eight ranked variables: (a) geomorphology (b) coastal slope (c) hinterland topography (d) facies (e) shoreline exposure (f) shoreline changes (g) tide (h) sea-level trend. Fifty six morphodynamic cells are deduced from a strictmorphologic classification of the studied coast. Each specified cell presents a numerical pattern according to the ranked physical and structural variables. Once managed, the beaches with the highest sensitivity are immediately disturbed. Littoral disturbance is irreversible when the foredune unit is damaged but sustainable remediation of coastal areas must emphasize with the adequate planning for the environmental rehabilitation.

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“…The Gulf of Gabes (southeastern Tunisia, figure 1) has received considerable attention by scientists interested especially in eustatic sea-level signals (Paskoff and Sanlaville 1983;Morzadec-Kerfourn 2002;Jedoui et al 2002Jedoui et al , 2003Morhange and Pirazzoli 2005;Anzidei et al 2011), hydrodynamic processes (Abdennadher and Boukthir 2006;Sammari et al 2006) and geodynamic evolution (Bouaziz et al 2003;Patriat et al 2003). The littoral of Jeffara basin (figure 1) provides an ideal site to study coastal changes at time scale, ranging from storm events to millennia, because large coastal forms exhibit short response time to external forces like winds, tide and RSL changes (Gzam et al 2013(Gzam et al , 2014Mauz et al 2015). The global MIS 5e sea-level curve includes two fluctuations: the rise before 130 ka, a period of stability (at 130-118 ka) some meters above modern sea level and the fall at ∼115 ka.…”

Section: Introductionmentioning

confidence: 99%

Late quaternary sea level changes of Gabes coastal plain and shelf: Identification of the MIS 5c and MIS 5a onshore highstands, southern Mediterranean

2016

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The continental shelf of the Gulf of Gabes is outlined, during the MIS 5c and MIS 5a onshore highstands, by the genesis of forced regressive beach ridges situated respectively at-19 m b.s.l/100 ka and-8 m b.s.l/80 ka. This area, considered as a stable domain since at least the last 130 ka (Bouaziz et al. 2003), is a particular zone for the reconstruction of the late quaternary sea-level changes in the region. Shuttle Radar Topography Mission (SRTM) data and field observations are highlighted to deduce interaction between hydrodynamic factors and antecedent topography. Variations in geomorphology were attributed to geological inheritance. Petrography and sedimentary facies of the submerged coastal ridges reveal that the palaeocoastal morphology was more agitated than today and the fluvial discharges are consistent. Actual morphologic trend deduced from different environment coasts (sandy coasts, sea cliffs and tidal flat) is marked by accumulation of marine sands and progradation. Keywords. MIS 5c and MIS 5a; beach ridges; sea level changes; palaeocoastal morphology; Gulf of Gabes; Tunisia.

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Genesis and Evolution of A Beach-Ridge Plain Reflecting Relative Sea-Level Rise: A Case Study From Trab El Makhadha Gulf of Gabes, Southeastern Tunisia

Cited by 8 publications

References 36 publications

Alarming coastal vulnerability of the deltaic and sandy beaches of North Africa

Alarming coastal vulnerability of the deltaic and sandy beaches of North Africa

Assessment of the Coastal Sensitivity Using the CS Index in the Gulf of Gabes Tunisia; Southern Mediterranean Coast

Late quaternary sea level changes of Gabes coastal plain and shelf: Identification of the MIS 5c and MIS 5a onshore highstands, southern Mediterranean

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