Hydrology and fluvial geomorphology 1.1

Question 1

How is the earths water distributed across the globe?

Answer 1

• 97% is in the sea.
• 2.1% is frozen as snow and ice.
• 0.8% is fresh water in rover lakes and the ground.
• 0.1% percent is in the atmosphere.

Question 2

What are the inputs and outputs of the the drainage basin system?

Answer 2

Input
- Precipitation: rainfall onto the surface of the drainage basin.

Output

• Evaporation: the change in state from liquid to gas.
• Evapotranspiration: evaporation of water which plants release from respiration.
• River discharge: water leaving the system through streams.

Question 3

What are the stores of the drainage basin system?

Answer 3

• Interception: water than is intercepted by plants, branches and leaves.
• Soil water: water stored in upper levels of the soil.
• Surface water: water stored in puddles and ponds etc.
• Groundwater: water that is stored in rock or soil.
• Channel storage: water stored in river channel.

Question 4

What are the above ground flows of the drainage basin system?

Answer 4

• Through-fall: water flows from leaves and foliage onto the ground.
• Stemflow: flow of water down a stem onto the ground.
• Overland flow/surface runoff: water flows above ground where it cannot infiltrate.
• Channel flow: flow of water through a river channel.

Question 5

What are the below ground flows of the drainage basin system?

Answer 5

• Infiltration: the movement of water from above ground into the soil.
• Percolation: water from soil into porous rock.
• Throughflow: water flowing through the soil and into rivers or streams.
• Groundwater flow: water flowing through permeable rocks below the water table.

Question 6

What is an aquifer?

Answer 6

A large body of porous rock or sediment that serves as a storage reservoir for large volumes of groundwater.

Question 7

What is the difference between an unconfined aquifer and a confined aquifer?

Answer 7

Unconfined - connected to the surface where its level can rise and fall.
Confined - enclosed by layers of unsaturated rock.

Question 8

What is the water table?

Answer 8

The level between saturated and unsaturated soil.

Question 9

What is groundwater recharge?

Answer 9

A process where water moves downward from surface water to groundwater to refill depleted levels.

Question 10

What are springs?

Answer 10

A natural outlet of ground water caused by the water table meeting the surface.