water and rivers

Question 1

.what are the three courses of a river ?

Answer 1

upper course, middle course and lower course

Question 2

name some types of erosion -

Answer 2

abrasion, attrition, corrosion / solution, hydraulic action

Question 3

what is abrasion ?

Answer 3

the process in which the banks and bed are worn down by the rivers load - stones etc,

Question 4

what is attrition ?

Answer 4

the load of the river ( material - rocks and stones ) bump into each other and so are smoothed and broken down into smaller particles

Question 5

what is corrosion/solution ?

Answer 5

this is a chemical action of river water, the acids in the water wear away the bed and banks.

Question 6

name two flooding case studies

Answer 6

pakistan and tewksbury

Question 7

effects of the 2007 tewksbury flood ?`

Answer 7

main road flooded

tourism affected

no power to 300,000 people

sewage systems damaged

many evacuated

people lost their jobs

severn trent water shut down, costing them £25 million

Question 8

effects of the pakistan flood ?

Answer 8

over 1, 700 people died

20 million affected through damaged property

1.2 million homes destroyed

widespread food and freshwater shortages

10 million poeple were forced to drink unsafe water

10,000 schools were destroyed

the total cost was at an estimated $35 million

Question 9

longer term effects of the pakistan flood ?

Answer 9

lost infrastructure sets pakistan back years

devistated agriculture will cause years of food shortage

the flood makes pakistan more susceptible to future floods

Question 10

causes of the tewksbury flood ?

Answer 10

no flood defences

140 mm of rain fell in a few hours

low preassure system

confluence of 2 rivers - avon and severn

soils were already saturated

large amounts of constrution on the flood plains

Question 11

causes of pakistan flood ?

Answer 11

raised levees and protected banks contain the sediment and reduce the river capacity

western river managment systems have been wrongly transferred to asian rivers

deforestation was a major cause of the flood

deforestation is known to aggrivate floods by reducing the ability of the drainage basins to intercept inputs ( water )

in july 2010, more than half the normal annual monsoon rains fell in just one week. Intense rainfall totalling in excess of 200mm fell in a 4 day period.this record monsoon rainfall assosiated with la nina was the highest in a 50 year period.

Question 12

what is a confluence ?

Answer 12

where 2 rivers meet

Question 13

what is the river mouth?

Answer 13

where the river meets open water

Question 14

what is the watershed?

Answer 14

the boundry which divides one drainage basin from another

Question 15

what is a drainage basin ( catchment )?

Answer 15

the area from which water drains into a particular drainage basin.

Question 16

what is a tributary ?

Answer 16

a smaller river that flows into a larger one

Question 17

what is a meander ?

Answer 17

a curve or loop in the river, often formed where the river flows around an obstacle - e.g/ rock. Meanders can migrate over time, causing the flood plain to get wider. The flow of water on the outside of the bend is fast - causing erosion.

Question 18

what is an ox-bow lake ?

Answer 18

a horseshoe - shaped lake next to the river. it occurs when a meander neck breaks through ( maybe during a flood ). over time ox - bow lakes can dry up - leaving just an outline of where the meander flowed.

Question 19

what are floodplains ?

Answer 19

flat ground near the lower course of the river. When the river bursts its banks, water flows into this area.

Question 20

what are levees ?

Answer 20

levees form near the river and form over time. deposits of heavy material.

Question 21

what are deltas ?

Answer 21

deltas only form at the moth of the river. for a delta to form, large amounts of sediment must be carried by the sea. material is carried by the river but is dropped when there is no longer the energy to carry it because the water has stopped moving. ( reached open water )

Question 22

what are interlocking spurs ?

Answer 22

vertical erosion ( causing v shaped valleys ) may be disrupted by protruding hillsides. these are formed as the river takes the least ressistive path down the hillside, taking advantage of any weaknesses in the rock. these hillsides are known as interlocking spurs and block the view up the valley.