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Flashcards in rivers Deck (25)
1
Q

inputs into a drainage basin

A

tributaries

precipitation

2
Q

transfers in a drainage basin

A
```infiltration
stem flow
overland flow
through flow
groundwater flow
percolation```
3
Q

outputs of a drainage basin

A

transpiration

evapotranspiration

4
Q

storage in a drainage basin

A

surface stores
groundwater stores
soil water

5
Q

water balance

A

difference between inputs and outputs and the subsequent change in storage

6
Q

equation for water balance

A

precipitation = total runoff + evapotranspiration +/- storage (soil/rock)

7
Q

if precipitation exceeds runoff and evapotranspiration there is a..

A

positive water balance

8
Q

there is a negative water balance when..

A

runoff and evapotranspiration exceed precipitation

9
Q

soil moisture budget

A

the change in amount water stored in the soil throughout the year

10
Q

levels of evapotranspiration are highest in what season? why?

A

spring and summer, warmer temperatures lead to more plant growth and therefore more evaporation and transpiration

11
Q

discharge

A

the amount of water in a river flowing past a particular point at a given time (expressed in cumecs)

12
Q

bankfull

A

the amount a river channel can hold without flooding

13
Q

lag time

A

time between peak rainfall and peak discharge

14
Q

peak discharge

A

the point on a flood hydrography where river discharge is at its greatest

15
Q

base flow

A

the normal day-to-day discharge of a river; its the consequence of slow moving soil throughflow and groundwater seeping into channel

16
Q

discharge calculation

A

cross section area volume x speed

17
Q

rising limb of hydrograph

A

how quickly the river responds to a storm

18
Q

falling limb of hydrograph

A

how quickly the river returns to normal

19
Q

how deforestation affects river flows

A

deforestation means theres less vegetation to absorb precipitation so a river will flood more easily (creates a flashy hydrograph)

20
Q

how afforestation affects drainage basin

A

more interception of precipitation
more evapotranspiration
less flooding

21
Q

how rock type impacts drainage basin

A
```permeable = less flooding
impermeable = quicker surface flow, more flooding```
22
Q

how do slope angles impact flooding

A

steeper slopes = more runoff and surface flow so river floods more quickly

23
Q

percolation

A

movement of water down through ground

24
Q

stem flow

A

water runs down stems of plants

25
Q

ground water storage

A

water thats stored deep in the ground in bedrock