Drianage Basins Flashcards
1
Q
What is a drainage basin?
A
- an area of land drained by a river system
- it is an open system of inputs and outputs
2
Q
Inputs in a drainage basin
A
- precipitation
- mainly rain
- snow, hail, dew, frost
3
Q
Stores in the drainage basin
A
- interception
- surface storage - water in ponds or lakes
- soil storage - moisture in the soil
- channel storage = water held in a river or stream channel
4
Q
Flows in the drainage basin
A
- infiltration = water soaking into the soil (depends on soil type and structure)
- overland flow = (runoff) water flowing over the land
- channel flow = water flowing in the river or stream itself (rivers discharge)
- stem flow = water running down stems or trees
5
Q
Outputs in the drainage basin
A
- evaporation = water turning into water vapour
- transpiration = evaporation from leaves
- evapotranspiration = evap and trans together
- river discharge = (river flow)
6
Q
Water balance equation
A
P = Q + E +- change in storage
Precipitation = total runoff + evapotranspiration +- change in storage
7
Q
What does the water balance effect and what is it?
A
- how much water is stored in the basin
- the balance between inputs and outputs within a drainage basin
- when both are balanced = dynamic equilibrium
8
Q
What does a + balance mean?
A
+ = inputs are greater than outputs
9
Q
What does a - balance mean?
A
- = outputs are greater than inputs
10
Q
What is the water balance shown on?
A
- a soil moisture budget graph
- SMB = the amount of water stored in the soil throughout the year
