Rivers - Floods Flashcards

1
Q

Flooding

A

where land that is normally not underwater becomes submerged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

infiltration

A

Water sinking into the soil from the ground surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

discharge

A

amount of water than passes a given point on a stream or river bank within a given period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

interception

A

water prevented from reaching the surface by trees and grass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

physical causes

precipitation

A
  • continuous heavy rainfall + prolonged light rainfall - saturates the soil (aka fills pores w/ water)
  • sudden bursts/snow - (snow melts), infiltrates quickly, surface runoff increases, water will reach river quicker so the discharge increases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

physical causes

geology

A
  • impermeable rock - doesnt allow water to infiltrate = more surface runoff = increase in discharge
  • permeable rock - allows water to infiltrate, so waters store = decrease chance of flood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

physical causes

relief

A
  • steep slopes - more likely for surface runoff bc water doesnt have time to infiltrate bc its going down = higher discharge
  • flat + flood plains - lower risk bc water has time to infiltrate the soil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

human causes

urban land use

A
  • new infrastructure/new housing/disappearing gardens: increases area covered by impermeable surfaces = more surface runoff
  • new housing: rainwater will flow into gutters and into drains, can be built in place w/ high flood risk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

human causes

rural land use

A
  • deforestation: reduces interception = saturated soil = increased runoff = increased discharge
  • farming technique: removal of hedges, arable results in soil being bare
  • urbanisation: greenfield sites getting built on
  • climate change: extreme weather events, increased temp = more evap = more rainfall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

effects

social

A
  • Injury
  • Death
  • Loss of home
  • Loss of belongings
  • Damage to property
  • Stressful
  • Isolate – loss of roads
  • Loss of recreational facilities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

effects

economic

A
  • Rebuild/fixing damage
  • High insurance claims
  • Loss of work/employment
  • Loss of revenue for local area
  • House value could decline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

effects

enviornmental

A
  • Habitats lost
  • Loss of land
  • Disrupts breeding areas
  • Spread of pollution
  • Spread of disease
  • Large deposits of mud left behind
  • Unsanitary conditions if sewage/grains flood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Flashy Response

A

when a drainage basin responds quickly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

flashy hydrogaphy

basin size

A

small basins often lead to rapid water transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

flashy hydrogaphy

drainage density

A

high density speeds up water transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

flashy hydrographs

rock type

A

impermeable rocks helprapid overland flow

17
Q

flashy hydrogaphy

land use

A

urbanisation = rapid water transfer

18
Q

flashy hydrogaphy

relief

A

steep slopes = rapid water transfer

19
Q

flashy hydrogaphy

soil moisture

A

saturated soil= rapid overland flow

20
Q

flashy hydrogaphy

rainfall intensity

A

heavy rain may be more than vol that can be intercepted = rapid overland flow

21
Q

flat hydrograph

basin size

A

large basin = slow water transfer

22
Q

flat hydrograph

drainage density

A

low density = slow water transfer

23
Q

flat hydrograph

rock type

A

permeable rock = slow water transfer bc it mves in groundwater flow

24
Q

flat hydrograph

land use

A

forest = slower water transfer bc interception

25
# flat hydrograph relief
gentle slopes = slower water transfer
26
# flat hydrograph soil moisture
dry soil =slower water transfer
27
# flat hydrograph rainfall intensity
light rain = slower transfer
28
# hard engineering embankents
**advantages** * cheap compared to hard engineering * channel has more space * used for riverside footpaths * provide habitats for animals eg kingfishers and otters **disadvantages** * high maintance cost * no easy access for boats and fishing * false sense of security = not being prepped for floods * concrete lining displaces animals * ugly * breached water cant get back into the river = water lying on ground for a while
29
# hard engineering flood relief channel
**advantages** * artificial reed beds and grass-covered concrete sides = provide new habitats * no flooding in a particular area * footpaths & cycle tracks are built along channel, bird watching and nature reserves * lower insurance costs * value of homes increases = easier **disadvantages** * habitats disturbed * ugly * expensive + high maintance * displacment * some ppl protected at the expense of others
30
# hard engineering dams & reservoirs
**advantages** * boosts tourism * hydroelectric power * area around used by forestry to plant trees = employment * drinking water * no flood risk * new habitats **disadvantages** * relocation of ppl * communities break up * v expensive to build and mantain * less fertile soil = less yield bc of lack of sediment deposited downstream * algae builds up = deoxyginated water * may trigger earthquakes/landslides * floods areas of outstanding natural beauty = kills plants and animals
31
# hard engineering channel straightening
**advantages** * protects places from flooding * may prevent nesting sites from being lost * moves water away more quickly = reduced flood risk * straight course improves navig & increases trade opportuns * insurance cost goes down = homeowners more likely to invest **disadvantages** * v expensive * ugly * problem not solved just moved away * downstream floods effects animals * fast flow in straight sections = deposition of silt elsewhere = floods
32
hard engineering
use of artificial structures to prevent or control natural processes
33
soft engineering
work with natural river processes to manage the flood risk
34
# soft engineering flood warning and prep
**advantages** * cheap * doesnt intefer with natural river * ppl feel prepped & secure and can protect their stuff before = less impact **disadvantages** * some predictions may be wrong = unnecessary panic * not everyone has access to media * ppl actually have to do wht is said * damage still occurs * houses hard to sell * distrupts habitats & ecosystems * clear up is not good bc ppl forced into temp accom
35
# soft engineering floodplain zoning
**advantages** * lots of uk cities on floodplains * cheap * permeable surfaces remain * damage is less expensive bc only low value is effected **disadvantages** * limits development bc certain land cant be used * harded to enforce and plain in LICs * habitats on other greenfield sites are destroyed as development is forced elsewhere
36
# soft engineering planting trees
**advantages** * co2 absorbed * new habitat = increased biodiversity * grants from government * low maintance cost * can be done in LICs bc of low skill involved * reduces percipitation flooding bc interception **disadvantages** * large areas of land needed * natural habitats changed from grass to trees
37
# soft engineering river restoration
**advantages** * boosts tourism * little maintance * biodiversity increase * pretty * businesses not affected * reduces flood risk **disadvantages** * initial cost high * pssible damage to land nearby