Waterfalls And V Shaped Valleys

Question 1

How is a waterfall formed?

Answer 1

1. Juction between hard rock capping upstream and soft rock downstream and differential erosion
2. Splash back causes hydraulic action to weaken rocks behind fall, rock breaks off and indentation formed, continued undercutting and created overhang
3. Overhang breaks off and rocks become trapped into bed (plunge pool), undercutting continues and overhangs continue to form, breaking and moving upstream

Question 2

How does a waterfall create a gorge?

Answer 2

As waterfall moves upstream, it leaves a steep sided valley downstream

Question 3

What are the characteristics of a gorge?

Answer 3

Very narrow valley, very steep sides, located immediately downstream of waterfall, turbulent water, many areas of bare rock on sides, boulder on bed, river channel takes up most of valley floor