Calder Erosion Answers

1 = Abrasion - rocks carried along by the river wear down the river bed.

(Tip for memorising - Abrasion rubs the river down.

2 = Hydraulic Action - the force of the river against the banks

(Tip for memorising - Hydraulic Hits the 'H'edges..)

3 = Attrition - rocks being carried by the river smash together and break into smaller, smoother and rounder particles.

(Tip for memorising - Attrition is a war of attrition, bashing into each other)

4 = Solution - soluble particles are dissolved into the river

Tip for memorising - 'In solution' means you cant see it'

River erosion is happening all the time, on the sides, on the bottom, in the current either bashing rocks or carrying sand. Why is erosion happening all the time?

Floods

There is a lot of energy in moving water (try swimming against it), and that pressure continuously impacts on the surroundings, whatever they are. When the pressure is particularly high - when there is flooding, it can cause the bank to burst/break as happened to this part of the Calder on Boxing Day (2015) causing flooding in Whalley. The white building in the background here..

is the same as on right hand side in 1st River Calder photo.

The bank breached and came like a river across this road, leaving a trail of sand and gravel - showing erosion at work. (5 extra marks if you can say what sort of erosion bought that sand there - and it can be more than one type)