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Publication
Contribution of storms to shoreline changes in mesotidal dissipative beaches: case study in the Gulf of Cádiz (SW Spain)
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Advisor(s)
Abstract(s)
In this study an analysis of storminess and rates
of shoreline change is performed and discussed jointly in
four geomorphological units of the Gulf of Cádiz (SW Spain)
for the period of 1956–2010. For this purpose, storm events
are identified based on the following characteristics: wave
height above 2.5 m, a minimum duration of 12 h and events
with calm periods of less than 24 h were considered as a single
event. Subsequently, energy parameters are determined
in order to characterize storm-induced impacts. Conversely,
geographic information system (GIS) tools are used to measure
shoreline changes in aerial photographs and orthophotographs
of each site, selecting the high water line as shoreline
proxy. Each geomorphological unit is divided into different
behavioural patterns according to recorded coastal
changes, so that each one shows a particular behaviour.
In general the variability of shoreline changes that is explained
by storms and the relation between storm parameters
and coastal changes present better results in exposed areas
(Cádiz and Vistahermosa) than in sheltered areas (Valdelagrana
spit barrier) because the former are more sensitive
to storm impacts. On the contrary, in areas where there is
no relation between coastal changes and storm parameters
(Valdelagrana and Sancti Petri sand spit), it is suggested that
anthropogenic factors are the main forcing agents determining
shoreline behaviour. However, in these areas the storminess
also modulates coastline recession by increasing erosion
when the number of storms is high.