L’influence des actions anthropiques dans l’évolution historique d’un littoral sableux à forte dérive sédimentaire : la baie de Port-Bouët (Abidjan, Côte d’Ivoire)

Touré, Baba; Kouamé, Koffi Fernand; Collet, Claude; Affian, Kouadio; Ozer, André; Rudant, Jean-Paul; Barthélemy, Jean

doi:10.4000/geomorphologie.9990

Cited by 10 publications

(16 citation statements)

References 5 publications

(3 reference statements)

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“…According to the authors of [14], significant changes in the position of the coastline of the Wouri estuary were observed at the entrance to the estuary, namely the "Cape Cameroon" area, because it experienced a coastal retreat of more than 300 m for 30 years between 1986-2015. This dominance of variation by erosion in the area of the mouth has also been observed in other places in the world [40][41][42][43][44][45][46][47][48][49].…”

Section: Discussionsupporting

confidence: 71%

Temporal (1948–2012) and Dynamic Evolution of the Wouri Estuary Coastline within the Gulf of Guinea

Fotsi

Pouvreau

Brenon

et al. 2019

JMSE

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The Wouri estuary is located in the Gulf of Guinea on the Atlantic coast of Cameroon’s coastline plain (3°49′ and 4°04′ north latitude and 9°20′ to 9°40′ east longitude), and is strongly influenced by coastal dynamics that have remained unquantified over a long period of time. This study analyzed the historical evolution of the Wouri estuarine coastline between 1948 and 2012. Variations in the estuarine evolution of the Wouri were studied from (i) minute topographic extracts from 1948, (ii) 1996–1999 nautical charts, and (iii) 2012 spatial map vectors. The net temporal spatial variation rates were calculated using the statistical methods of the Digital Shoreline Analysis System (DSAS). These change rates were also calculated over two time intervals (1948–1996 and 1996–2012) and over a 64-year period (1948–2012). The study reveals highly disparate results. Indeed, kinematics show that the Wouri estuary was dominated by erosion in its downstream section, with 262.83 ha for –3.2 m/year and 110.56 ha for –5.8 m/year between 1948–1996 and 1996–2012 respectively, and by accretion on the other hand in its upstream section, with 239.17 ha for 4.3 m/year in zone 5 between 1948–1996 and 150.82 ha for 12.6 m/year in zone 4 between 1996–2012. Thus, over the 64-year period (1948–2012), we have a dominance of variation by erosion downstream and conversely by accretion upstream, marked by the presence of amplifying factors (anthropogenic pressure and climate change) of the rate of variation of morphological evolution at the beginning of the 21st century, as compared to the middle-20th century. The observed development of sediment loss and accumulation, both influences and will influence, the sediment regime along the Wouri estuarine coastline. There is a need to develop a systematic sub-regional coastal surveillance activity to effectively manage Cameroon’s coastline system.

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Section: Discussionsupporting

confidence: 71%

Temporal (1948–2012) and Dynamic Evolution of the Wouri Estuary Coastline within the Gulf of Guinea

Fotsi

Pouvreau

Brenon

et al. 2019

JMSE

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“…Although many studies have revealed particular human impacts on the CA [6,[26][27][28], Newton et al [29] grouped all of them in nine "syndromes" (references integrate studies describing each one in particular): (1) sediment syndrome [5,8,15,28,30]; (2) water syndrome [8,31,32];…”

Section: The Human Pressure On the Camentioning

confidence: 99%

Degradation of Coastlines under the Pressure of Urbanization and Tourism: Evidence on the Change of Land Systems from Europe, Asia and Africa

Petrişor

Hamma

Nguyen

et al. 2020

Land

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The importance of studying coastal areas is justified by their resources, ecosystem services, and key role played in socio-economic development. Coastal landscapes are subject to increasing demands and pressures, requiring in-depth analyses for finding appropriate tools or policies for a sustainable landscape management. The present study addresses this issue globally, based on case studies from three continents: Romania (Europe), Algeria (Africa), and Vietnam (Asia), focusing on the anthropogenic pressure resulting from land use/land cover change or urban sprawl, taking into account the role of socioeconomic and political factors. The methodology consisted of producing maps and computing and analyzing indicators, correlating geospatial and socio-economic data in a synergistic manner to explore the changes of landscapes, and identify the specific driving forces. The findings show that the pressure of urbanization and tourism on coastal areas increased, while the drivers and impacts vary. Urbanization is due to derogatory planning in Romania and Algeria, and different national and local goals in Vietnam. The two drivers determine local exemptions from the national regulations, made for profit. In addition to the need for developing and enforcing policies for stopping the degradation and restoring the ecosystems, the findings underline the importance of international cooperation in policy development.

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“…Amongst the coastal areas that are particularly at risk of climate change, those located on the Gulf of Guinea in West Africa rank very high [13,14]. According to Touré et al [15]; the West African coasts are undergoing a significant erosive process, which can be impressive in some places with average retreats exceeding 10 m per year. The city of Cotonou, the economic capital of Benin, is built on alluvial sand with a maximum thickness of 4 m [4] between Lake Nokoue in the North and the Gulf of Benin 1 in the South (Fig.…”

Section: Introductionmentioning

confidence: 99%

Perceptions of and responses to coastal erosion risks: The case of Cotonou in Benin

Longueville

Hountondji

Assogba

et al. 2020

International Journal of Disaster Risk Reduction

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Intensive erosion has affected the coastal zone of Cotonou for several decades. An analysis of satellite images showed an average coastline retreat of 115 m in the study area over the period 2002-2013 with several hundred houses destroyed. Since 2014, a stabilisation of the coastline is observed. This study aimed at identifying the atrisk population and at analysing the perceptions of people who experience and those who manage coastal erosion risk, as well as the responses adopted. Based on four criteria and their hierarchy, we identified five profiles of inhabitants in this risk zone. (1) Wealthy people who leave the zone when they are affected or (2) fall into the category of people in danger in case they cannot migrate. (3) Fishermen who deliberately stay near the sea. (4) The most precarious people, trapped in the risk zone. Finally, (5) poor newcomers who continually increase the at-risk population. With the recent stabilisation of the coastline, the national authorities manage the "hazard" component of the risk. However, the majority of the population is not serene. The anthropogenic stress linked to evictions gradually replaced the stress to be engulfed by the sea. We conclude that the "vulnerability" component of the risk is not yet resolved. All categories of the population in this sensitive area need to be secured. Cooperation among multiple levels of governance, the application of land use planning regulations and of the Kampala Convention and the involvement of local communities are all measures which will enable to meet this objective.

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L’influence des actions anthropiques dans l’évolution historique d’un littoral sableux à forte dérive sédimentaire : la baie de Port-Bouët (Abidjan, Côte d’Ivoire)

Cited by 10 publications

References 5 publications

Temporal (1948–2012) and Dynamic Evolution of the Wouri Estuary Coastline within the Gulf of Guinea

Temporal (1948–2012) and Dynamic Evolution of the Wouri Estuary Coastline within the Gulf of Guinea

Degradation of Coastlines under the Pressure of Urbanization and Tourism: Evidence on the Change of Land Systems from Europe, Asia and Africa

Perceptions of and responses to coastal erosion risks: The case of Cotonou in Benin

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