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| Titel |
Holocene coastline changes in the Guadalfeo River deltaic system of SE Spain |
| VerfasserIn |
Antonio Jabaloy Sánchez, Francisco José Lobo, Antonio Azor, Patricia Bárcenas, Luis Miguel Fernández-Salas, Víctor Díaz del Río, José Vicente Pérez-Peña, Mercedes Vázquez-Vílchez |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048245
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| Zusammenfassung |
| The Guadalfeo River is located in the central sector of the Betic Cordillera (SE Spain). It has
a 1252.44 km2 catchment draining a highly mountainous region towards the Mediterranean
Sea. River management (dam building and channel deviation) has controlled the very recent
coastline evolution and the activity of the submerged parts of the delta, with subsequent
modification of the main depositional areas. This recent evolution has been reconstructed
from historical maps, aerial photographs, submarine multibeam bathymetric data and
high-resolution seismic surveys.
We have distinguished three main evolutionary stages, whose development took place as a
consequence of the changing natural and anthropic influences on the river system. The first
stage started with the formation of an estuary during the Holocene eustatic maximum at
4000-2000 BC (Hoffmann, 1987). The coastline advanced seawards from this moment on
until 1500 AD, finally forming a delta. The coastline reconstruction at around 1500
AD is well documented with historical references to a narrow coastal plain and
several lagoons. This 3500 year-long stage of estuary infill is characterized by an
increase of around 6x106 m2 in the surface of the delta along a sinuous 12 km long
coast, indicating a mean advance of the coastline of around 500 meters at 0.15
m/y.
The nautical charts by Montojo y Salcedo (1876) depict the natural channel and the
presence of a very asymmetric delta associated with the natural river mouth. Between 1500
and 1873 AD, the delta increased its area by 13x106 m2, showing a mean advance of the
coastline of 1232 meters in 376 years.
The second and third stages of evolution are characterized by anthropic interventions in
the catchment and the river mouth. The second stage corresponds with the XX century and
coincided with the construction of the Harbour of Motril from 1908 to 1927 and the waterway
diversion of the natural mouth during the thirties of the last century. The new river’s mouth is
located 1800 meters westwards of the ancient natural one. The coastal dynamics
changed during this second stage with erosion of the original delta eastwards of
the Harbour. The third stage (2003 AD to present day) started with the damming
of the trunk river in the central sector of the catchment, thus drastically reducing
sediment supply to the coastal realm, thus triggering erosion and coastline retreat. |
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