Floodplains
Floodplains = result of both erosion and deposition.
The accumulation of river deposits = suggests =predominately depositional features.
Relatively flat areas of land either side of the river= form the valley floor in the middle+ lower courses of the river.
Composed of alluvium - river deposited silts and clays.
Floodplain= becomes wider and the depth of sediment accretions= increases.
The width of the floodplain= determined by the amount of meander migration + lateral erosion that has taken place.
Lateral erosion = most powerful just downstream of the apex of the meadner bend.
Results in the migration of meanders= leaving their scars clearly visisble on the floodplain.
Interlocking spurs = removed by lateral erosion in the middle course- leaving behind a bluff line + widening the valley.
Alluvial deposits = depends partly on the amount of flooding in the past- floodplain creation is linked to extreme events.
Point bars + old meanders scars become incorporated into the floodplain= adding to the alluvial deposits.
These become stabilised by vegetation as the meanders migrate + abandon their former courses.
The accumulation of river deposits = suggests =predominately depositional features.
Relatively flat areas of land either side of the river= form the valley floor in the middle+ lower courses of the river.
Composed of alluvium - river deposited silts and clays.
Floodplain= becomes wider and the depth of sediment accretions= increases.
The width of the floodplain= determined by the amount of meander migration + lateral erosion that has taken place.
Lateral erosion = most powerful just downstream of the apex of the meadner bend.
Results in the migration of meanders= leaving their scars clearly visisble on the floodplain.
Interlocking spurs = removed by lateral erosion in the middle course- leaving behind a bluff line + widening the valley.
Alluvial deposits = depends partly on the amount of flooding in the past- floodplain creation is linked to extreme events.
Point bars + old meanders scars become incorporated into the floodplain= adding to the alluvial deposits.
These become stabilised by vegetation as the meanders migrate + abandon their former courses.
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