Water on the Land

- Hard rock lies on top of soft rock 

- Softer less-resistant rock is eroded more quickly by hydraulic action and the harder rock is undercut

- Overhang is unsupported and collapses under gravity into the base of the waterfall adding large angular boulders

- Boulders swirl around in base of waterfall, eroding into smaller pieces by attrition 

- A deep plunge pool is created by abrasion (boulders hitting base of waterfall)

- Process repeats over time and the waterfall retreats back to its source, with a narrow, steep sided gorge of recession marking its path

- When river reaches a meander, water is thrown to the outside of the bend

- Increases velocity and reduces friction of river at the outside bend

- River has excess energy here so can transport a lot of material which erodes the bank by abrasion

- Bank becomes undercut and will collapse leaving a small river cliff, adding load to the river, and  causing the river to retreat sideways.

- This widens the vally floor and erodes interlocking spurs

- On inside bend, there is a slower current and velocity so the river has less energy

- Meterial is deposited leaving a slip-off slope 

- Erosion processes on the outside bend (abrasion, hydraulic action) cause the meanders to move laterally towards each other

- At times of floodimg the river has lots of energy and will be able to cut through the narrower meander neck to form a straighter channel by hydraulic action and abrasion.

- The fastest current will now flow through the centre of the straightennened channel and there will be little water flow in the meander, eventually leaving stagnant water with low evergy so the river deposits its load here

- Deposition occurs on near the banks where the lowest current is and this will seal the meander off from the channel completely, leaving am ox-bow lake

- Over time, the water in the ox-bow lake will drain away and leave sediment, leaving a meander scar.