Estuaries are the interface between man and the sea. and they are the channels for the impact of man on the marine environment. Because they are to a greater or lesser extent connected to the sea. they have traditionally been regarded as part of that seemingly infinite resource. or at best an open-ended means of access to it. This approach has led to conflicts between the users of the estuary. and with the increase not only in population but more particularly in the developed countries in manufacturing output. these conflicts have become more and more acute . The estuary should always be...