The Shoreline between Nature and Society, a Changing Heritage - Vulnerability of Coastal Ecosystems and Adaptation - page 194

numerous as the needs for sediments, we have naturally turned toward
the most abundant source of sediments in principle - and for the
philistines - the source offered by the sea. Sediment extraction is not a
recently discovered activity: for decades, part of the coastal
urbanization, in particular in the case of many beach resorts, is the
result of this practice. It was convenient to dig into the bordering
dunes (many caoudeyres are nothing more than quarries), or even the
beaches themselves. For instance, when it was attempted to refill the
beach of Baule (almost for the first time in France at such a scale), it
was decided that approximately the same amount than what was taken
in the years 1950 and 1960 would be deposited. Similarly, the
improvement of acidic farmland in Brittany was achieved with
calcareous sand extracted from the bottom of the sea in shallow
waters, named maerl; many small Breton estuaries still undergo this
movement on a periodic basis and, in theory, in a controlled
environment. The monitoring of sediment extraction is the double
consequence of the particular care borne to the environment over the
last three decades and to the realization that the sediment scarcity on
the seaside is not a scientific fantasy: the growing effects of coastal
erosion are the expression of it [BIR 85, PAS 81, PAS 93]. Coastal
erosion not only occurs locally but at various scales and is the
observed consequence of a given depletion of sediments, which itself
is related to the combination of man-made structures around streams
(dams, spikes, dikes which increase the energy of the water flow, etc.),
of the control exerted over watersheds (plantations in some Moroccan
wadi, for example, which have slowed down the sediments on their
way to the mouths of the wadi and thereby contributed to
the considerable erosion of the large beach of Agadir), but also to a
certain degree of depletion of the shallow pools offshore, as if the end
of the Flandrian transgression had exhausted the last stocks available.
However, this remains a debate among specialists.
All these elements contribute in explaining the gravity of the
problem of sediment extraction offshore. The needs are considerable;
the European Union (EU) recently reported that no less than
50 million m 3 were extracted each year from the North and the Baltic
Seas at less than 60 m depth, and these needs are likely to