Environmental Engineering Reference
In-Depth Information
Fig. 1.
Approximate distribution, according to Pirazzoli (1991), of the typical relative mean
sea-level curve types A, B and C as shown in Fig. 2.
Fig. 2.
Approximate relative mean sea-level curves for the zones A, B, and C shown in Fig. 1.
landscape. Where sea level rose, Holocene estuaries were drowned and
new wetlands formed landward.
In coastal environments, continuous change is the paradigm. Whatever
the Holocene relative sea level curve is, coastlines worldwide are still
evolving, estuaries are not at a steady state and coastal wetlands continue
to migrate. Through this chapter, we will consider these changes in the
geological time scale as the reference state or “normal” pattern, and we will
focus on those changes that are affecting the world's coastal environments
within time scales of days to centuries. Human activities can modify rates
of natural changes, and there are evidences of anthropogenic actions that
have signifi cantly enhanced changes driven by natural agents. As we cannot
separate human activities from natural changes, we will consider not just
ecological changes driven by global atmospheric and climate alterations, but
also coastal change created by human use of water on land, and increased
erosion of terrestrial sediments, as well as direct human destruction of
coastal habitats.
