Catchment hydrology - processes of the water cycle

Question 1

What is evaporation

Answer 1

The phase change of liquid to water vapour

Main pathway by which water enters the atmosphere

Question 2

Latent heat

Answer 2

The energy input of evaporation does not lead to an increase in temperature
Instead the energy is absorbed as latent heat and released later in condensation

Question 3

Interception

Answer 3

Vegetation intercepts a proportion of precipitation, storing it temporarily on branches, leaves and stems
This water will either evaporate or fall to the ground
Throughfall - rainwater which is briefly intercepted before dripping on to the ground
Stemflow - during prolonged or intense periods or rainfall, intercepted rainwater may flow to the ground along branches and stems

Question 4

What is infiltration

Answer 4

By gravity into the soil and lateral movement or throughflow to stream and river channels

Question 5

What is overland flow

Answer 5

Across the ground surface either as a sheet or as trickles and rivulets to stream and river channels

Question 6

explain flow paths

Answer 6

Overland flow is related to the soils infiltration capacity
When rainfall exceeds the soils infiltration capacity overland flow occur.
Rainfall, regardless of its intensity, always infiltrates the soil, overland flow only occurs when soil becomes saturated and the water table rises to the surface
Saturated overland flow

Question 7

Geology

Answer 7

Where soils are underlain by permeable rocks, water percolates deep underground
This water then migrates slowly through the rock pores and joints as groundwater flow
This eventually emerges at the surface as springs or seepages

Question 8

Cryospheric processes

Answer 8

Ablation is the loss of ice from snow, ice sheets and glaciers
Melting, evaporation and sublimation

Question 9

Meltwater

Answer 9

An important component of river flow in high latitudes and mountain catchments in spring and summer