Cearreta, Alejandro

Evans, Graham

Portal de Revistas Científicas Complutenses

Foreword
Human Impact on the Coast
Impacto humano sobre la costa
ISSN (print): 1698-6180. ISSN (online): 1886-7995
www.ucm.es /info/estratig/journal.htm
Journal of Iberian Geology 34 (2) 2008: 165-166
Man has had an impact on the coastline since ear-
liest times but it has been during the last two cen-
turies (The Anthropocene) when human interference 
of coastal areas has become, by far, the main factor 
affecting its geomorphologic evolution. Coastal de-
velopment for commerce, industry and in recent de-
cades by the widespread migration of people to the 
coast for settlement and tourism have increased the 
pressure on this zone. Also, the growing demand for 
clean energy sources is likely to result in the insta-
llation of centres for the development of wind, wave 
and tidal energy in or near the coast.
Now with the changing climate, sea-level rise, in-
creasing storms and the violence of rainfall, the vul-
nerability of the coast and its settlements is becoming 
a matter of growing concern.
It has also been realized that the coastal environ-
ment is greatly inﬂuenced by changes in the hinter-
land, particularly in the river basins-deforestation, 
changing agricultural practices, mining and the de-
velopment of new cities all have an impact on the 
coast, even if they are thousands of miles away, by 
increasing the ﬂux of sediments, nutrients and pollutants. 
Evans in the ﬁrst paper of this volume attempts to review 
some of these changes and inﬂuences and the likely fu-
ture scene.
Rocky coastlines are probably the part of the coast least 
affected by man. However, Neves has shown how the cli-
ffs of Rocha do Gronho, Portugal, have suffered increa-
sed erosion due to man-induced changes in the adjacent 
area and the decrease of beach sand moving alongshore 
to provide protection of the base of the cliff.
The interference of alongshore transport of sand by the 
construction of groynes and jetties and the maintenance 
of dredged channels across the nearshore zone is one whi-
ch has produced the greatest problems. It has led to the 
necessity of expensive coastal protection schemes which 
often have had further repercussions along the adjacent 
coast. This is clearly demonstrated by Rodriguez et al. 
to be a major problem on the Huelva coast, SW Spain. 
Similarly, Pedrosa and Freitas show how recent deve-
lopments of the Espinho-Paramos coast, Portugal, have 
resulted in the ampliﬁcation and propagation of coastal 
erosion.
JIG 34-2.indb   165 17/07/2008   20:44:42
166 Editorial / Journal of Iberian Geology 34 (2) 2008: 165-166
supply to the Sado estuary, Portugal, which has however 
unfortunately again increased in parts of the estuary due 
to the development of an industrial complex.
Mil-Homens et al. give a clear warning of the wides-
pread inﬂuence of human activities beyond the coastline. 
In spite of the high-energy sandy nature of the continental 
shelf off Portugal there are local areas of mud accumula-
tion. These are sites of distinct historical enrichment of 
heavy metals which must come from distant sources and 
have been spread offshore.
It is hoped that this short collection of papers, covering 
the various aspects of man’s impact on the coastline of 
Iberia, will help in making more scientists aware of the 
changes which have already taken place due to human acti-
vities. These are likely, unless a great deal of care is taken, 
to become exacerbated in the future because of increasing 
coastal development and the predicted climatic changes. 
The coast is a very fragile environment and both it and the 
adjacent hinterlands need to be treated carefully unless we 
will leave a dreadful legacy for future generations.
Alejandro Cearreta
Departamento de Estratigrafía y Paleontología
Facultad de Ciencia y Tecnología,
Universidad del País Vasco/EHU
Apartado 644, 48080 Bilbao, Spain
alejandro.cearreta@ehu.es
Graham Evans
Department of Ocean and Earth Sciences
National Oceanographic Centre 
University of Southampton
European Way, Southampton SO14 3ZN, U.K
Formerly Imperial College, London, U.K..
Dredging and maintenance of estuarine outlets has be-
come increasingly necessary in order to keep channels 
free of sediment and to accommodate the ever-increasing 
size of ships. An interesting subsidary effect of such ac-
tivity is described by Monge-Ganuzas et al. from the 
Oka estuary, Spain. There, dredging and the dumping of 
sand on nearby beaches and intertidal areas, to increase 
the depth of the channel which gives access to a shipyard 
located on the inner estuary, has modiﬁed the ebb-del-
ta at the estuary mouth and also the breaking pattern of 
the famous “Mundaka left wave”. This caused the for-
ced cancellation of the world famous Billabong Pro surf 
championship with disastrous results to the local eco-
nomy. Fortunately, the situation has reverted to its former 
pattern and the famous breaking wave has been restored. 
The development of industry in estuaries and coastal 
inlets has led to a great loss of coastal wetland habitats 
as well as pollution, all of which produce adverse ecolo-
gical effects. Interestingly, Cearreta et al. demonstrate 
that in spite of the development of the largest oil reﬁnery 
in Spain in the Muskiz estuary, there is little evidence of 
chemical pollution, although the loss of coastal habitats 
is considerable. Similarly, Irabien et al. show that the 
Santoña marshes, N Spain, have not suffered the feared 
chemical pollution due to substantial local development 
and change in land usage.
In contrast, Prego et al. show that the human activities 
associated with the harbours and shipyards of the Gali-
cian rias have left a clear geochemical imprint on the bo-
ttom sediments. This is severe in the rias of Ferrol and 
Vigo and, as yet, only moderate in those of Pontevedra 
and La Coruña. Freitas et al. show how the changing pat-
tern of mining in the hinterland has led to a decrease of 
JIG 34-2.indb   166 17/07/2008   20:44:42


Impacto humano sobre la costa

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Impacto humano sobre la costa

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