what are v shaped valleys?
deep narrow valleys with steep sides that resemble the letter “V”
found in the early stages of a river journey where vertical erosion is dominant
how are v shaped valleys formed?
the river erodes the bed(bottom) more than the sides cutting deep into land vertical erosion
over time weathering weaken the valleys sides causing them to collapse and form the characteristic v shaped valley
what are waterfalls?
a vertical drop in the rivers course where water flows over a ledge
common in areas with resistant (hard) rock layers over softer rock.
how are waterfalls formed?
- the river flows over a layer of hard rock sitting above softer rock .
- the softer rock erodes faster, creating a step
- as erosion continues the step becomes steeper forming a waterfall
- the force of the falling water erodes a plunge pool at the base
- overtime the waterfall retreats upstream leaving a gorge behind
what are gorges?
deep narrow valleys with steep sides often formed as waterfalls retreat
how are gorges formed?
when a waterfall erodes backward (upstream retreats) it craves out a deep valley
the process continues over thousands of years deepening and extending the gorge
what are potholes?
circular holes in the riverbed ranging from small to large
how are potholes formed?
fast moving water carries small rocks and pebbles
these get trapped in hollows and swirl around grinding down the through abrasion
over time the hole deepens and widens forming a pothole
