Water Cycle Pack B

Question 1

What are the flows in the water cycle and where do each take from from and to?

Answer 1

• Absorption (land to vegetation)
• Precipitation and evaporation (between vegetation and atmosphere, land and atmosphere, ocean and atmosphere)
• Consumption (vegetation to animals)
• Runoff (land to ocean)

Question 2

What are the 6 main stores in the water cycle and what percentage of water is in each?

Answer 2

• Ocean 97% (saltwater, covers 71% of Earth’s surface)
• Cryosphere 2% (high latitude and high altitude glacial areas, permafrost)
• Groundwater and soil moisture 1% (below surface, affected by climate/geology)
• Terrestrial surface water 0.01% (rivers and lakes, influenced by climate change)
• Atmosphere <0.01% (water vapour)
• Biosphere flora and fauna <0.01% (influenced by climate)

Question 3

How does the world’s water cycle and a drainage basin show characteristics of open and closed systems?

Answer 3

• The world’s hydrological cycle is a closed system as energy enters and leaves but matter doesn’t enter or leave
• A drainage basin is an open system as energy and matter enters and leaves

Question 4

What is the cryosphere and where is water stored in ice globally?

Answer 4

• Areas of the Earth where water is frozen into snow or ice
• Includes ice sheets, caps, glaciers, sea ice and permafrost

Question 5

Why does the mass balance exist with the world’s water cycle?

Answer 5

• The total volume of water is conserved at a global scale

Question 6

What are the inputs, outputs and stores for a drainage basin?

Answer 6

• Input is precipitation (e.g. rain, sleet, snow, hail)
• Stores include interception, vegetation, surface water, soil moisture, channel and groundwater store
• Outputs include evaporation, transpiration and river discharge

Question 7

What is overland flow?

Answer 7

Movement of a sheet of water over the land surface, towards a lake, river or ocean, sometimes at very fast rates

Question 8

Why does long duration, large volume or intense rain cause overland flow?

Answer 8

• Causes large amounts of water

Question 9

After rain falls it can evaporate or it can flow over or through the ground. Which are the faster flows and which are the slower flows and why?

Answer 9

• Flowing over the ground is the fastest (50 - 500m/hr)
• Flowing through the soil is second fastest (soil pores = 0.5 - 30cm/hr, animal burrows = 50 - 500cm/hr)
• Flowing through the ground is slower (jointed limestone = 10 - 500cm/hr, pores in sandstone = 0.1 - 100cm/hr), shale = negligible flow)

Question 10

After rain falls what two types of runoff exists and what causes each?

Answer 10

Saturation excess overland flow:
- Follows long-duration rainfall
- The depth at which throughflow (and saturation of soil pores) occurs gradually rises until it reaches the surface
- At this point, overland flow begins

Infiltration excess overland flow:
- Follows high intensity rainfall
- Rain doesn’t have a chance to infiltrate so flash-flooding can occur
- Water runs straight off the ground
- Mostly occurs in semi-arid regions, where ground has been hard-baked