PORT ECONOMICS

Then, many rivers are afflicted at their mouths with
what are termed Bars, i.e. ridges of material which are
due to various causes, some of them obscure, resulting
in a diminution of depth of water at the very threshold
of the port. Immense sums of money have been expended
in dredging operations at notable ports throughout the
world with a view to the removal of these bars, or, at any
rate, to a lowering of their crests. At Liverpool, since
the year 1890, when dredging operations were commenced,
no less than 400 million tons of sand have been removed
from the bar of the Mersey and the approach channels to
the port; the operation is necessarily continuous, since
the bar tends to reform. At the mouths of the Mississippi,
of the Danube, of the Volga and other rivers, extensive
dredging has been necessary for the same reason.

At other river mouths, where bars are not definitely in
evidence, there are shoals and banks of mud and sand
which impede the channels and dredging has frequently
to be resorted to for their removal. The entrances to the
ports of London, New York and Hamburg may be quoted
as examples.

All these considerations go to show that no situation
of a port from a physical point of view can be considered
as altogether perfect, and in each case the best has to be
made of the circumstances which obtain.

HINTERLANDS

But the outstanding fact is, that the ports have their
inception and tend to develop, solely in accordance with
the dictates of trade requirements, along the line of
recognized traffic routes, and no amount of convenience
and suitability will originate and foster a port where the
inducement of trade is lacking. There are plenty of
harbours and coastal inlets where ports could be established
with the requisite degree of shelter and accommodation,
were it not that the absence of conditions favourable
to trade militate against the attraction of shipping.

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