hydrosphere

Question 1

Study diagrams Q15A and Q15B. Explain the changing river levels at Stratfordon-Avon between the 5th and 13th of April.

Answer 1

-lag time
-base level
-steep/shallow rising limb
-steep/shallow recession limb
-Peak river discharge

Question 2

Explain how a meander is formed

Answer 2

in a straight river channel, a river may have to twist and turn round an obstruction such as a boulder. The river flows fastest on the outside of the bend increasing the erosive power. This allows erosion to occur through processes such as Hydraulic Action - where air is forced into cracks in the river bank creating explosive blasts which dislodge material - and solution - where soluble rocks react with acids in the water causing them to dissolve. The river flows slower on the inside of the bend which causes deposition to occur. This transfers eroded material and forms a river beach,

Question 3

explain the formation of an ox-bow lake

Answer 3

-formation of a meander-
Meanders become more pronounced overtime and during times of flood, when the river has more energy, It may cut through the neck leaving a cut-off ox-bow lake. An example of an Oxbow lake is Lake Chicot.

Question 4

Explain the formation of a Waterfall

Answer 4

Waterfalls occur where areas of hard rock are overlying areas of sort rock allowing differential erosion to occur due to soft rock being more easily eroded than the hard rock. Erosion occurs through processes such as Hydraulic Action - where air is forced into cracks in the river bank creating explosive blasts which dislodges material - and solution - where soluble rocks react with acids in the water causing them to dissolve. Undercutting causes an overhang of hard rock to become unsupported over time. Gravity will cause the an overhang to collapse into the plunge pool. The plunge pool can be further deepened by material from the collapse. The waterfall will then retreat upstream.