Drainage Basin As An Open System

Question 1

The drainage basin is an open system as there are inputs and outputs of both energy and matter. What are inputs into the system?

Answer 1

Energy-potential energy

Matter-precipitation and sediment

Question 2

How may precipitation enter a drainage basin and what are other stores

Answer 2

Directly into the river itself
Onto the land surface
Caught on vegetation

Vegetation, soil, groundwater, surface storage

Question 3

How does Interception work and what else acts as interception and stores asides from vegetation?

Answer 3

-Vegetation intercepts precipitation by being held on leaves, before evaporating into the atmosphere or by throughflow and stem flow
-Vegetation reduces water passing through the system

Hollows and depressions eg puddles,ponds,lakes
Underground stores eg rocks, soil

Question 4

Examples of transfers

Answer 4

Overland flow/surface run off - water moving across the land
Infiltration- water soaking into the soil
Throughflow- water moves through soil layer parallel to the surface
Percolation- water moving from soil to underlying rock

Other: stem flow, through fall, groundwater flow, sediment transport

Question 5

What is infiltration, infiltration capacity and what happens if it is exceeded?

Answer 5

Movement of water into the soil
Rate at which infiltration occurs
Overland flow occurs

Low infiltration: frozen soils
High infiltration: large numbers of trees (infiltrates through roots)

Question 6

What is Percolation and where do groundwater supplies occur

Answer 6

Downward movement of water from the soil into the deeper stores such as groundwater

Areas of permeable (rocks with cracks) and porous rock (has tiny holes) eg sandstone, chalk and limestone

Question 7

What are outputs of the drainage basin

Answer 7

-Discharge to the sea
-Evapotranspiration- combined loss of water through transpiration and evaporation
-Sediment discharge
-Energy

Evaporation- movement of water from land or sea into the atmosphere by the heat of the sun

Transpiration- loss of moisture from vegetation back into the atmosphere during photosynthesis via the stomata

Question 8

What are evaporation rates affected by and what do transpiration rates depend on

Answer 8

Evaporation:
Temperature
Wind speed
Humidity
Hours of sunshine
Climatic factors

Transpiration:
Time of year
Type/amount of vegetation
Availability of moisture
Length of growing system