Sand Dunes - Land-Locked
Sand dunes form wherever environmental conditions provide sand,
steady wind and a location for the sand to collect. This may occur
in both coastal and terrestrial settings.
Sand starts as bedrock,
which is broken down into blocks, a size at which water is able
to transport them downstream. Eventually these large blocks may
be jostled around enough to be broken into sand-sized
grains. Sand and other sediment
usually ends up deposited along the sides of streams, in lakes,
or in the ocean, but what happens when it doesn't? An ephemeral,
or seasonal stream, during its dry periods, is exposed to wind.
Occassionally a lake will dry up, with its sediment left without
the protection of water. These two sources feed land-locked dune
There are many examples of terrestrial dune fields within the National
Park Service system. Listed below are Parks containing land-locked
dunes. Click here to learn
more about dune formation and coastal systems.