Processes Operating Within Hydrological Cycle

Question 1

Define hydrological cycle

Answer 1

Continuous cycle of water within the earth’s atmosphere. Is a closed system

Question 2

Define closed system

Answer 2

A closed system occurs when there is transfer of energy (not matter) between the system and its surroundings. (Inputs come from within system)

Question 3

Define open system

Answer 3

Open system received inputs and transfers outputs of energy and matter to other systems

Question 4

Examples of stores in hydrological cycle

Answer 4

Ocean
Ice caps
Groundwater
River/lakes
Soil moisture

Question 5

Define global water budget

Answer 5

The annual amount of water transferred/stored in hydrological cycle. Including stores/fluxes/flows

Question 6

Define aquifer

Answer 6

Permeable rock which stores water

Question 7

Define a drainage basin

Answer 7

An area of land drained by a river/tributaries and separated from neighbouring basins bu a watershed divide

Question 8

Is a drainage basin an open or closed system

Answer 8

Open
As it is linked to other systems by inputs and outputs involving processes and stores

Question 9

What is the physical factor affecting drainage basin inputs x1

Answer 9

Precipitation
Major input for any basin. But the type/ intensity of precip and global location (climate/season) of basin affects rate of input

Question 10

What are physical factors affecting drainage basin flows x6

Answer 10

Interception
Infiltration
Through flow
Surface runoff
Percolation
Groundwater flow

Question 11

Define interception

Answer 11

Precipitation prevented from reaching ground surface due to vegetation. Water intercepted evaporated back into atmosphere

Question 12

Define infiltration

Answer 12

Movement of water vertically (down) in the soils pores

Question 13

Define through flow

Answer 13

Water moving laterally (sideways) through soil. Downslope due to force of gravity

Question 14

Define surface runoff

Answer 14

Water flowing over ground surface due to: saturated overland flow
Infiltration excess overland flow

Question 15

Define percolation

Answer 15

Water moving vertically downwards through/into permeable rock

Question 16

Define groundwater flow

Answer 16

Water moving sideways through a permeable rock under the influence of gravity

Question 17

Define Input

Answer 17

Addition of matter/energy

Question 18

Definition of output

Answer 18

Removal of matter/energy

Question 19

Define processes/flows

Answer 19

Water moving/ the process

Question 20

Define store

Answer 20

Storing water

Question 21

Name some examples of human disruption to the drainage basin

Answer 21

Hard engineering
Deforestation
Dam construction
Groundwater abstraction

Question 22

Explain a case study for human disruption to water cycle

Answer 22

Amazonia, South Africa
There is dense vegetation and canopies which allows for heavy local rainfall but a self sustaining cycle.
However deforestation causes a significant loss in evapotranspiración and rainfall. With a 25% increase in river discharge due to deforestation.

Question 23

How does dam construction disrupt the drainage basin/water cycle

Answer 23

Dams increase surface water stores and evaporation. Reduce downstream river discharge.

Aswan Dam Egypt estimated evaporation loss of 10-16 billion cubic metres per year. Leading to a loss of 20-30% volume in River Nile

Question 24

Define water budget

Answer 24

Water budgets show the annual balance between inputs/outputs. Water budget allows comparison of supply and demand. Expressed as

P=Q+E+/-S

Precipitation= channel discharge Q+ evapotranspiration E +/- change in storage S

Question 25

Define/explain the four points on a water budget

Answer 25

Soil moisture surplus- soil moisture at capacity and can be used for plants.

Soil moisture utilisation- water stores gradually being used up by evaporation/transpiration

Soil moisture deficiency- soil water has been used up. Period of drought

Soil moisture recharge- soil stores start to fill up again as precipitation levels increase

Question 26

Define a river regime

Answer 26

Describes the annual variation in the discharge of a river, usually includes seasonal variations

Question 27

Define a storm hydrograph

Answer 27

Shows variation in rovers discharge at specific point over a short period of time
Storm event

Question 28

Name the 12 factors affecting the storm hydrograph

Answer 28

Drainage basin size
Drainage basin shape
Drainage basin relief
Soil type
Rock type
Drainage density
Natural vegetation
Land use
Precipitation intensity
Precipitation duration
Snowfall
Evapotranspiration

Explanation on pg 37