fresh water from land enters the ocean through
rivers,streams and groundwater flowing through
extremely narrow stream cut chennels to remarkably
broad lagoons behind long barrier islands, are called
estuaries.
the powerful flow of water in major rivers
maintains channels that are deep enough
for navigation by ocean bound vessels and
the rivers themselves provide
transportation of goods to poinsts farther
inland
the types of estuaries that are no
viable as pors of call for ocean
commerce are those that are not
wide enough, no deep enough and
not powerful enough to prevent the
builduo of sediment.
During the last ice age,
much of what is today the
submerged continental
shelf was exposed as an
extended part of the
continent.