Senechal N., Laibi R. A., Almar Rafaël, Castelle B., Biausque M., Lefebvre Jean-Pierre, Anthony E. J., Dorel Matthieu, Chuchla Rémy, Hounkonnou M. H., Penhoat Yves du. (2014). Observed destruction of a beach cusp system in presence of a double-coupled cusp system : the example of Grand Popo, Benin. Journal of Coastal Research, (no spécial 70), p. 669-674. ICS 2014 : International Coastal Symposium, Durban (ZFA), 2014/04/13-18. ISSN 0749-0208.
Titre du document
Observed destruction of a beach cusp system in presence of a double-coupled cusp system : the example of Grand Popo, Benin
Année de publication
2014
Auteurs
Senechal N., Laibi R. A., Almar Rafaël, Castelle B., Biausque M., Lefebvre Jean-Pierre, Anthony E. J., Dorel Matthieu, Chuchla Rémy, Hounkonnou M. H., Penhoat Yves du
Source
Journal of Coastal Research, 2014,
(no spécial 70), p. 669-674 ISSN 0749-0208
Colloque
ICS 2014 : International Coastal Symposium, Durban (ZFA), 2014/04/13-18
Beach cusps are common features of steep reflective and intermediate beaches. However, very few observations have reported double coupled cusp systems. Here, we present a dataset of observations of a beach exhibiting two sets of beach cusps. Data were collected at Grand Popo Beach (Benin, West Africa) in February 2013. Daily topographic surveys along a 380 in long stretch of shore allowed observation of the dynamics of the two sets of beach cusps. At the beginning of the field survey, we clearly observe two sets of cusps; the upper beach cusps system is relatively asymmetric with a typical wavelength of about 45 m, while the lower beach cusps system is relatively symmetric with a typical wave length slightly shorter (about 35 m). After two days, we measured the total destruction of the lower set of beach cusps while the upper set of beach cusps was only partially destroyed. The data suggest that destruction of the lower beach cusp system may be related to persistent accretionary conditions and/or calm conditions but probably also to the transition from wave-driven circulation (dominated by weak alongshore currents with flash and swash rips), to a second period characterized by dominant longshore currents further increasing in speed (with rare swash rips). Conversely, the disappearance of the western upper beach cusp may be related to an accretionary pattern and to the coalescence of two individual features. Our observations, consistent with previous works, suggest that beach cusps certainly arise as a result of some combination of erosion and accretion.
Plan de classement
Sciences du milieu [021]
;
Limnologie physique / Océanographie physique [032]
;
Géologie et formations superficielles [064]
Description Géographique
BENIN
Localisation
Fonds IRD [F B010063188]
Identifiant IRD
fdi:010063188
