Natural England?
A lot of the land in eastern Essex, and in Suffolk and Norfolk, is below sea level. This is most easterly part of England to the north of the Thames estuary, on the edge of the North Sea. It is mostly marshland that has been reclaimed from the sea at various points over the last couple of thousand years.
This reclaimed marshland is protected from flooding by a vast network of seawalls and drainage ditches – which allow rainwater to run off at low tide. And these seawalls have to be constantly maintained, because the tides and currents of the river on the other side are constantly working to erode them. … Read more »