283
The most important morphological features identified in the stage of characterization, correspond to coastal spits; the Magdalena River Delta; the submarine canyon; the sources of sediments (Magdalena River and small continental streams);
coastal dunes; and coastal infrastructure. The selection of these morphological attributes is related to the fact that they correspond to those physical entities that more
influence in the shape of beach and their evolution in time. Therefore, the borders of
littoral cell were defined to considering in the left extreme of Bocas de Ceniza
Groin; and the other side, the cells ends in the cliffs located at “Punta Roca”. It has
a subsystem (subcells) that ends in the intersection zone with the León Stream when
it opens the lagoon mouth.
Another aspect to consider, in detail, in the morphological analysis is to determine the marine structures built by men, identifying the affection grade that this
intervention has had on the current shape of the beach. To give more physical sense
to the study, results of morphological analysis are used to give a diagnosis that
allows understating the causes and effects that led to the configuration of the coastline and, in general, of the littoral cell.
The bar of Mallorquín Lagoon is contained in a littoral cell confined between
two physical borders: (a) Bocas de Ceniza Groin (Breakwater); and (b) Punta Roca
(Cliff located at the west of the wetland). It is not observed along the coastline any
type of physical, natural or artificial element that can influence in the morphological
configuration of the whole cell or in the shape of beach. The most relevant feature
from the geomorphologic perspective is related to the formation of a coastal spit in
proximities of the groin to maintain the navigability activities (Bocas de Ceniza
Groin). The beach presents a parabolic profile where the sand is the predominant
material. Just in the western region of the littoral cell, it is identified rocky elements
(cliffs or abrasion platforms) in the beach as shown in Fig. 9.2.
The beach has a variable section in plant throughout its length, with a mean
width of 121 m. Additionally, it describes a defined discontinuity by a lagoon mouth
that connects the wetland with the sea. This mouth has a dynamism associated with
the wave climate variability and the oceanographic processes (currents, waves and
tides). This is closed during the most part of the year, holds a width of 24.78 m
approximately, but commonly it generates a channel at the end of the year
(November, December) by with the influence of North Winds, Cold Fronts and
extreme hydro-meteorological phenomena. Its position has varied in time to the
present, and it is not expected to change physical conditions that have endured during last decades.
9.2.1.1 Impacts and Diagnosis
Perhaps, the event that triggered main changes in morphological level was the construction of the coastal structure as shown in Fig. 9.3. In ancient times, the system
was composed of a cove and a set of bars generated by sediments from the Magdalena
River. Subsequently, in the 1930s began the construction of a navigability channel
in the Magdalena River, the Port Terminal and the works of shelter of the external
9 Physical and Morphological Changes to Wetlands Induced by Coastal Structures
The most important morphological features identified in the stage of characterization, correspond to coastal spits; the Magdalena River Delta; the submarine canyon; the sources of sediments (Magdalena River and small continental streams);
coastal dunes; and coastal infrastructure. The selection of these morphological attributes is related to the fact that they correspond to those physical entities that more
influence in the shape of beach and their evolution in time. Therefore, the borders of
littoral cell were defined to considering in the left extreme of Bocas de Ceniza
Groin; and the other side, the cells ends in the cliffs located at “Punta Roca”. It has
a subsystem (subcells) that ends in the intersection zone with the León Stream when
it opens the lagoon mouth.
Another aspect to consider, in detail, in the morphological analysis is to determine the marine structures built by men, identifying the affection grade that this
intervention has had on the current shape of the beach. To give more physical sense
to the study, results of morphological analysis are used to give a diagnosis that
allows understating the causes and effects that led to the configuration of the coastline and, in general, of the littoral cell.
The bar of Mallorquín Lagoon is contained in a littoral cell confined between
two physical borders: (a) Bocas de Ceniza Groin (Breakwater); and (b) Punta Roca
(Cliff located at the west of the wetland). It is not observed along the coastline any
type of physical, natural or artificial element that can influence in the morphological
configuration of the whole cell or in the shape of beach. The most relevant feature
from the geomorphologic perspective is related to the formation of a coastal spit in
proximities of the groin to maintain the navigability activities (Bocas de Ceniza
Groin). The beach presents a parabolic profile where the sand is the predominant
material. Just in the western region of the littoral cell, it is identified rocky elements
(cliffs or abrasion platforms) in the beach as shown in Fig. 9.2.
The beach has a variable section in plant throughout its length, with a mean
width of 121 m. Additionally, it describes a defined discontinuity by a lagoon mouth
that connects the wetland with the sea. This mouth has a dynamism associated with
the wave climate variability and the oceanographic processes (currents, waves and
tides). This is closed during the most part of the year, holds a width of 24.78 m
approximately, but commonly it generates a channel at the end of the year
(November, December) by with the influence of North Winds, Cold Fronts and
extreme hydro-meteorological phenomena. Its position has varied in time to the
present, and it is not expected to change physical conditions that have endured during last decades.
9.2.1.1 Impacts and Diagnosis
Perhaps, the event that triggered main changes in morphological level was the construction of the coastal structure as shown in Fig. 9.3. In ancient times, the system
was composed of a cove and a set of bars generated by sediments from the Magdalena
River. Subsequently, in the 1930s began the construction of a navigability channel
in the Magdalena River, the Port Terminal and the works of shelter of the external
9 Physical and Morphological Changes to Wetlands Induced by Coastal Structures