I. The Coastal Zone
15
The timescale involved in environmental responses (physical and biological) to
natural and man-made events may vary considerably. A catastrophic pollution
event can lead to a rapid and almost total destruction of the flora and fauna in the
contaminated zone. Again, excessive exploitation of biological resources,
exceeding the natural capacity of the species to reproduce, may result in a gradual
extinction of these species. The limits of sustainability have then been exceeded.
At sea, discharges of toxic products, even in relatively small quantities, can (over
a period of years) have equally catastrophic consequences, particularly when
toxic substances enter foodchains and concentrate to high, and increasingly toxic,
levels. In coastal sedimentology, beach evolution provides an excellent example
of the diversity of time scales. Indeed, sediment transport phenomena on the
littoral fringe may be recognized, operating at different scales from nearinstantaneous transport such as sediments placed in suspension due to waves, to a
millennium variation of the shoreline, with yearly and seasonal changes in
between.
A first step is the formulation of a "health report" for the coast, in which three
types of zones can be identified :
a) zones that are still intact and able to undergo some development in the near
future ;
b) endangered zones, because they are particularly fragile, such as estuaries,
deltas, lagoons, or sandy shores undergoing continual evolution ;
c) already damaged zones, because of chemical and/or biological pollution, or
because of insensitive development (e.g. sites of camping grounds or
construction at the sea's edge liable to erosion).
Based on this identification, two kinds of action can be undertaken : continuous
and individual. So far, France, for example, has achieved :
Continuous actions :
type "R6seau National d'Observation de la Qualit6 du Milieu Marin" :
survey and control of water quality in clearly bounded zones ;
type "Surveillance Ecologique du Blayais" : establishment of an ecological
reference state prior to development, followed by monitoring of the milieu's
evolution after development (e.g. a nuclear power station near Blaye);
the case of an unconsolidated littoral in continual evolution, with on-going
surveillance in the form of a sedimentary dynamic stud)' (collection of beach
profiles at regular intervals, determination of volumes of eroded or accreted
sediments, and so on).
15
The timescale involved in environmental responses (physical and biological) to
natural and man-made events may vary considerably. A catastrophic pollution
event can lead to a rapid and almost total destruction of the flora and fauna in the
contaminated zone. Again, excessive exploitation of biological resources,
exceeding the natural capacity of the species to reproduce, may result in a gradual
extinction of these species. The limits of sustainability have then been exceeded.
At sea, discharges of toxic products, even in relatively small quantities, can (over
a period of years) have equally catastrophic consequences, particularly when
toxic substances enter foodchains and concentrate to high, and increasingly toxic,
levels. In coastal sedimentology, beach evolution provides an excellent example
of the diversity of time scales. Indeed, sediment transport phenomena on the
littoral fringe may be recognized, operating at different scales from nearinstantaneous transport such as sediments placed in suspension due to waves, to a
millennium variation of the shoreline, with yearly and seasonal changes in
between.
A first step is the formulation of a "health report" for the coast, in which three
types of zones can be identified :
a) zones that are still intact and able to undergo some development in the near
future ;
b) endangered zones, because they are particularly fragile, such as estuaries,
deltas, lagoons, or sandy shores undergoing continual evolution ;
c) already damaged zones, because of chemical and/or biological pollution, or
because of insensitive development (e.g. sites of camping grounds or
construction at the sea's edge liable to erosion).
Based on this identification, two kinds of action can be undertaken : continuous
and individual. So far, France, for example, has achieved :
Continuous actions :
type "R6seau National d'Observation de la Qualit6 du Milieu Marin" :
survey and control of water quality in clearly bounded zones ;
type "Surveillance Ecologique du Blayais" : establishment of an ecological
reference state prior to development, followed by monitoring of the milieu's
evolution after development (e.g. a nuclear power station near Blaye);
the case of an unconsolidated littoral in continual evolution, with on-going
surveillance in the form of a sedimentary dynamic stud)' (collection of beach
profiles at regular intervals, determination of volumes of eroded or accreted
sediments, and so on).