Water Cycle - Booklet 1

Question 1

Is the global hydrological cycle a closed or open system? Justify your answer.

Answer 1

A closed system because there are no inputs or outputs, the amount of water is finite and constant.

Question 2

Name 4 stores within the global hydrological cycle (from largest to smallest)

Answer 2

1) The oceans
2) Glaciers and ice sheets
3) Surface runoff
4) The atmosphere

Question 3

Define the term “drainage basin”

Answer 3

Is an open subsystem operating within the closed global hydrological cycle, it is defined as an area of land drained by a river and its tributaries with a boundary (aka watershed)

Question 4

Outline 2 factors influencing input rates to the drainage basin

Answer 4

Input - precipitation (rain, hail, snow, sleet etc…)

1) Seasonality: in some climates (e.g monsoon and Mediterranean) there are strong seasonal patterns of rainfall, thus the time of year determines precipitation rates)

2) Latitude: the location of the basin has a major impact on climate, and so the volume and type of precipitation falling; in higher latitudes there is a colder climate and thus snowfall occurs more than rain fall.

Question 5

Describe the 3 types of rain fall

Answer 5

1) Convectional: often a daily occurrence, (water cycle rain)

2) Frontal/cyclonic:

Question 6

What is meant by “interception”

Answer 6

Refers to direct interference or plants/leaves in changing the direction or temporarily stopping precipitation. Any moisture retained by the surface of the leaves is know as interception store (capacity will depend on vegetation type)

Question 7

Define what is meant by “infiltration” and “infiltration capacity”

Answer 7

Refers to the movement of water from the surface to the soil, infiltration capacity is the maximum rate at which water can be absorbed by the soil.

Question 8

Outline 3 factors that influence infiltration rates

Answer 8

1) Soil composition: sandy soils have large pores compared to clayey soil, thus water moves more quickly.

2) Type and amount of vegetation: Dense roots can inhibit the infiltration of water, abundance of vegetation can also lead to high interception rates; some vegetation will also have a higher saturation capacity.

3) Relief: sloped land will promote more runoff, therefore less infiltration as a direct result.

Question 9

Define what is meant by surface “run off”

Answer 9

Water flows over land, rather than permeating deeper levels of the ground, is also the primary transfer of water to river channels.

Question 10

Define what is meant by “through flow”

Answer 10

Water moves through the soil and into the streams or rivers, speed of flow is dependent on type of soil.

Question 11

Define what is meant by “percolation”

Answer 11

Water moves from the ground or soil into porous rock or fractures (deeper bedrock or aquifers)

Question 12

Outline the 2 outputs of the drainage basin

Answer 12

1) Evaporation: the direct loss of water moisture from the surface of a body of water, the soil and interception storage (top of leaves).

2) Transpiration: this is where water is sequestered to the atmosphere via the pores of plants (stomata).

Question 13

Name 4 storages within the drainage basin

Answer 13

1) Soil water
2) Ground water
3) Surface storage (puddles, lakes, ponds etc..)
4) River channel

Question 14

Outline 5 physical factors influencing the drainage basin

Answer 14

• Climate: influences amount of rainfall and vegetation growth
• Soil composition: influences rates of infiltration and through flow
• Geology: affects percolation and ground water flow
• Relief: steeper gradient will promote faster rates of surface runoff
• Vegetation: affects interception, overland flow

Question 15

Outline 5 anthropogenic factors influencing the drainage basin

Answer 15

• Cloud seeding: substances are dispersed within the air to enable for condensation, e.g china 2008 Beijing games to try and reduce pollution levels
• Deforestation: less vegetation, less interception, less infiltration, more overland flow, can lead to flooding
• Afforestation: more vegetation, more interception, less overland flow, more evapotranspiration
• Urbanisation: impermeable surfaces (e.g pavements) reduce infiltration and percolation, river discharge increases
• Construction of dams: reduction in downstream river flow and discharge, increase in surface stores means more evaporation

Question 16

Define the term “river regime”

Answer 16

Is the annual variation in discharge of a river at a particular location