Set answer questions

How are waterfalls formed [4 marks] (give an example)

High force is an example of a waterfall on the river tees. More resistant rock, Whinstone, is layered above a less resistant rock. Overtime, due to hydraulic action and abrasion the softer rock underneath erodes. This leaves an overhang of rock behind. Eventually, the overhang collapses as it’s unsupported and due to gravity , it collapses into the plunge pool and the debris is used to deepen the plunge pool and create a taller waterfall. The waterfall retreats further back as the process repeats and it creates a steep suede gorge where the waterfall was.

How are oxbow lakes formed [4 marks]

As meanders become more exaggerated due to hydraulic action and abrasion, the meander migrates across the floodplain and continues to become more exaggerated. The neck of the meander narrows and the outside bend erodes until the river creates a channel between , this leaves behind a straight channel and deposition blocks of the meander to create an oxbow lake.

What are the characteristics of meanders? [4 marks]

The outside bend of a meander is deeper due to there being faster flowing water which has more energy causing the bank to erode due to hydraulic action and abrasion. The inside bend is shallower and water is much slower as there is more friction due to the water having low energy so there is more deposition on the inside of the bend forming a slip off slope.

How are levees formed ? [4 marks]

Levees are natural embankments along the edge of a river channel. During a flood eroded sediment is deposited over the floodplain. The heaviest material is deposited closest to the river channel because it gets deposited first as the river slows. The finer material is deposited further away on the flood plain. Over time, the deposition of the larger sediment builds up creating levees on the edges of the channel.