Hydrosphere

Question 1

The Hydrological Cycle

Answer 1

The Sun heats water from the ocean, lakes, rivers and Earth’s surface. This water then evaporates into the atmosphere. Additional water is drawn from the soil by plants, and is then evaporated into the atmosphere from leaves and stems. This process is called transpiration. As the air rises and the temperature drops, the moisture filled air condenses, forming clouds and eventually resulting in precipitation in the form of rain or snow. Surface run-off makes its way back to the ocean via rivers. Other water seeps downwards into the soil. This process is called infiltration. If the rock below the soil is permeable, then the water percolates the rock and is stored as groundwater.

Question 2

Human Impact on the Hydrological Cycle

Deforestation

Answer 2

• Within developed countries, major land use in the drainage basin system is forestry - forests are deforested for commercial purposes, in developing countries forests are deforested for a number of reasons
• Trees store water, however, if they’re cut down less water is stored and therefore an increase in surface run off and through flow

Question 3

Irrigation

Answer 3

• Water used in farming to irrigate land and crops to increase farming output
• Farmers store water to use for irrigation purposes. Can reduce water flow within drainage basin

Question 4

Urbanisation

Answer 4

• Increased urbanisation = removal of natural vegetation with replacement of impermeable surfaces, eg. concrete which will increase surface run off through system
• man made drainage & sewage systems returns water in the drainage system quicker = higher river levels

Question 5

Dams, Reservoirs and HEP

Answer 5

• Due to increasing demand for fresh clean water and in renewable energy, sections of the drainage basin are dammed to store water within a catchment
• As a result the water is intercepted and cannot complete the hydrological cycle = reduces flow of water through drainage system