As the Murray River travels through this flat
strech of land it starts to wander back and forth. This wandering
cause large curves in the river to form. The current of the river
is always pushing and eroding the outside of the curve causing it
to grow and cut farther and farther into the land. This is because
the fastest part of the current is forced to flow along the outside
curve, by inertia, speeding up the erosion and the slowest part of
the river travels along the inside curve. The faster the current
the more sediment it can carry. Because of this some of the
sediment drops out of the water along the bank just above the
inside turn of the river. And as a result, the outside bank is
eroded away and the inside curve stays about the same.
Over time the meanders become more and more
pronounced. The outside curve is eventually eroded away until the
two sides of the river on each side of the neck of land flood over
and meet, cutting off the out route of the river and froming a new
channel for the main current. Eventually more sediments are washed
up and completely block off the old section of the river, forming
an oxbow lake, better known in Australia as a billabong.
At this location we can observe the process of
forming a new billabong. To get credit for this earthcache email me
the answers to the following questions:
1. The GC code and name of this earthcache.
2. The number of cachers in your group.
3. From where you are standing where is the area of most erosion
and why do you think it is located there?
4. How far is it to the area with the fastest flow of water?
5. What material is the beach made of and how did it get
here?
6. How far into the process of creating a billabong is this
meander?
7. To prevent armchair caching, either take a picture of the river
at the posted coordinates with yourself or your GPS in it or
describe to me the texture of the sand along the beach.
