Paper 1, Section C - Rivers 1

Question 1

Long profile:

Answer 1

• concave shape
• starts at the source and has a steep gradient until it reaches the mouth of the river as the gradient becomes more flat.

Question 2

Processes:

Answer 2

U.C: vertical erosion:
Hydraulic action and attrition

M.C: mostly attrition, some hydraulic action, less vertical and lateral erosion begins in high discharge.

L.C: erosion is reduced- down lateral erosion takes place on the outside of meanders where the flow is fast ( hydraulic action)

Question 3

Features:

Answer 3

U.C: waterfalls, rapids, v-shaped valley, interlocking spurs.

M.C: small meander and a small flood plain, u-shaped valley.

L.C: big meanders and large flood plain. Oxbow lakes. Levées. Estuaries

Question 4

Bed-load:

Answer 4

U.C: Large rocks and angular

M.C: medium pebbles and sub-rounded.

L.C: sand, fine gravel and silt (mud) which is well rounded

Question 5

Transport:

Answer 5

U.C: traction - large rocks rolled in high discharge

M.C: some traction but smaller gravel bounced along by saltation. Sand and silt floats in suspension.

L.C: mostly suspension

Question 6

Deposition:

Answer 6

U.C: when discharge is decreased, large rocks are deposited.

M.C: deposition of pebble in low flow are also on inside of meander

L.C: deposition on inside of meander bends on flood plains when river flows and sediment is deposited in size order; largest by channel causing levées. Mudflats at mouth of estuary.