eq1 - physical factors affecting drainage basin Flashcards

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1
Q

what is the drainage basin

A

an open system that is an area of land that is drained by a river and its tributaries

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2
Q

what are the 3 types of inputs affecting the hydrological cycle

A
  1. convectional- ground warms causing evaportation which casues intense weather
  2. orographic- warm moist air forced to rise overupland areas causing rainfall
  3. frontal- moist air meets colder polar ari forming rain
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3
Q

what are the physical factors affceting the drainage basin

A
  1. interception
  2. infiltration
  3. percolstion
  4. direct runoff
  5. saturated overland flow
  6. infiltration excess overland flow
  7. growndwater flow
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4
Q

what is intercerption

A

raindrops are prevented from from falling directly onto the ground surface due to the layer of vegetation

vegetation prevents the rate of precipitation

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5
Q

what is infiltration

A

where water is absorbed

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6
Q

what is percolstion

A

similar to inflitration however involves deeper transfer of water into permeble rock

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7
Q

what is direct runoff

A

water flowing over the surface of the ground

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8
Q

what is saturated overland flow

A

occurs when water accumulates in the soil and cannot absorb any more water. This causes water to run off the surface.

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9
Q

what is infiltration excess overland flow

A

occurs when rainfall intensity exceeds
the infiltration capacity so excess water flows over the ground surface

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10
Q

what are the 3 physical factors affceting the driange basin outputs

A
  1. evaporation
  2. transpiration
  3. channel flow
    4.
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11
Q

what is channel flow

A

water that has been collected to flow in a river or stream

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12
Q

what

what is evapotranspiration

A

the total amount of water removes from the drainaeg basin by th eporcess of transpiration and evaporation

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13
Q

name the 5 factors whihc determine the importance of the flows outputs and inputs

A
  1. climate
  2. soils
  3. veg
  4. geology
  5. relief
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14
Q

vegations contibution

A

transpiration increases deu to more vegeation
vegetaion with a low albedo wiill reflect will absorb more solar rad meaing increased evaporation

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15
Q

climates contribution

A

– influences
amount of rainfall and
vegetation growth.

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16
Q

soils contribution

A

nfluences rate of infiltration
and throughflow.

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17
Q

geologys contibution

A

affects
percolation and
groundwater flow

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18
Q

relief conribution

A

➢ Relief – steeper gradients
of land will encourage faster
rates of surface runoff

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19
Q

name the 4 human disruptions of the drainage basin

A

cloud seeding
urbanisation
dam construction
groundwater abstraction

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20
Q

what is cloud seeding

A

this is the attempt to change the amount or type of preciptation by dispersing substances into the air.

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21
Q

what is urbanisationan and what does it create

A

urbanisation creates impermeable surfaces that reduce infiltration adn increase surface runoff

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22
Q

what is dam construstion and what does it create

A

dams increase surface water stores
adn evaporatioon and reduce downstream river discharge

23
Q

what

what is groundwater abstarction

A

groundwater is abstacted from some aquifers faster than it is replaced

24
Q

h

what is a water budget

A

shows the annual balance bewteen inputs(precip)and outputs(evapotranspiration, channel flow).

25
Q

what is a river regime

A

the annual variation in the dischareg of a river

26
Q

what is the watershed

A

boundary of the drainage basin

27
Q

how has defroestation affcted the amazonian river

A

-has lowered humidity’s
-less precipitation
-more surface runoff
-more evaporation, less transpiration
-more soil erosion and slit being fed into the rivers.

28
Q

decribe the features fo the amazonian rainforest

A
  1. 6308 km long
  2. drains a basin of nearly 6 million km2
  3. humid tropical climate
  4. peak discharge in may, lowest in september
29
Q

what is the discharge of a river

A

the volume of water flowing through a river channel

30
Q

describe the features of the yukon river

A
  1. 3540 km long
    2.drainage basin area of 850,000
    3.tundra climate
    4.peak dischareg in may, lowest in decemeber
    5.
31
Q

describe the features of the river nile

A
  1. changed deu to the aswan dam
  2. flow was reduced by 65%
  3. flood peaks in september
    4.
32
Q

what does a stormhydrograph show

A

variations in rivers discharge at a specific point over a short period of time

33
Q

what are the main features of a storm hydrograph

A

-the rising limb
-peak discharge
-lag time
-falling/ recessional limb
-base flow

34
Q

rising limb

A

where the discharge starts to rise after the rainfall starts

35
Q

peak discharge

A

reached after the peak rainfall
-its the greatest vol of water-flooding may occur

35
Q

base flow

A

where the rivers dischareg eventually returns to normal

35
Q

lag time

A

the interval between the peak rainfall and the peak discharge

36
Q

falling limb

A

once the rainfall starts to decrease so deos the discharge

36
Q

what the two ways a storm hydrograph can be described

A

flashy and subdeud

37
Q

what is a flashy hydrograph

A

very steep limbs(rising)

1)high peak discharge
2) short lag time

38
Q

what is a subdued hydrograph

A

hydrographs with gently inclined limbs
1)low peak discharge
2)long lag time

39
Q

de

describe the drainage basin size of a flashy and subdued hydrograph

A

f=small basin
s=large basin

40
Q

describe the drainage basin shape of a flashy and subdued hydrograph

describe the drainage basin shape of a flashy and subdued hydrograph

A

f-circular basin
s-enlongated basin

41
Q

describe the drainage basin relief of a flashy and subdued hydrograph

A

f-steep slope
s-gentle slope

42
Q

describe the soil type of a flashy and subdued hydrograph

A

f-clay soils, thin, low porosity-water infiltrates slowly
s-sandy soils and thick soils-high porotity-more infiltration

43
Q

describe the rock type of a flashy and subdued hydrograph

A

f-imperable rock-increases surfaec runoff
s-permeablel rocks

44
Q

describe the rock type of a flashy and subdued hydrograph

A

f-imperable rock -increases surface runoff
s-permable rock-

45
Q

describe the drainage density of a flashy and subdued hydrograph

A

f-high drainage density
s-low drainage density

46
Q

describe the natural vegetation of a flashy and subdued hydrograph

A

f-thin grass-intercepts little water
s-forests and woodland-intercepts water-high evaporation rates

47
Q

describe the land use of a flashy and subdued hydrograph

A

f-urban surfaces-harder surfaces-carry water more rapdily to water sources
s-rural-vegetated surfaces-intercept water-allow interception-travel slower to water sources

48
Q

describe the preciptation intensity of a flashy and subdued hydrograph

A

f-high intensisty-
s-low intensity

49
Q

describe the preciptation duration of a flashy and subdued hydrograph

A

f-prolonged-water table rises and soil becomes saturated
s-short duration-

50
Q

describe the snowfall of a flashy and subdued hydrograph

A

f-fast snowmelt
s-slow snowmelt

51
Q

describe the evapotranspiration of a flashy and subdued hydrograph

A

f-low rates-fewer losses from the drainage basin
s-high rates- high evapotranspiration losses will reduce discharge into the river channel