Unit 4.1 The water cycle

Question 1

The water cycle (hydrological cycle)

Answer 1

describes continuous movement of water on, above, and below the surface of the Earth. Where water is always changing states between liquid, vapor, and ice.

Driven by solar radiation

Question 2

Distribution of Earth’s water

Answer 2

1. Saline water = 97%
2. Fresh water = 3 %
   - ground water 30.1%
   - ice caps and glaciers 68.7%
   - others 0.9 %
   - fresh surface water 0.3% (rivers 2%, swamps 11% and lakes (87%)

Question 3

The water cycle (fundamental to draw and explain)

Answer 3

Storages:

• Oceans
• Soil
• Groundwater
• Lakes
• Rivers and streams
• Atmosphere
• Glaciers and ice caps

Flows:

1. Transfers
   - Advection (movement of cloud)
   - Surface run off
   - Flooding
   - Inflitration and percolation
   - Stream flow
2. Tranformations
   - Evaporation
   - Evapotransportation (evaporation + respiration = water from plants evaporates)
   - Condensation
   - Freezing
   - Sublimation (solid to gas)

Question 4

What drives the water cycle?

Answer 4

Solar radiation

Question 5

Impact of human activity

Answer 5

Small and large scale human manipulation of water has significantly altered global patterns of stream flow. Resulting changes in sea level, ocean salinity, and in biophysical properties of the land surface could ultimately generate climate feedbacks.

Question 6

Global ocean conveyer belt

Answer 6

constantly moving system of deep ocean circulation driven by temperature and salinity

Question 7

Human activity on water

Answer 7

1. Withdrawals (for domestic use, agricultura and industry)
2. Discharges (adding pollutants to water)
3. Changing the speed and direction of water flow (dams, reservoirs, canals…)

Question 8

Leaching (soil and water)

Answer 8

Leaching: Through the process of percolation, water moves downward through soil, dissolving and transporting soluble substances.

Consequences: loss of essential soil nutrients and the potential contamination of groundwater sources.