52469
Description
Mind Map by maddiemurchie23, updated more than 1 year ago
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Created by maddiemurchie23
almost 12 years ago
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The drainage basin hydrological
cycle: the water balance & flooding case studies
- Drainage basin: open
- Input: Precipitation
- Flow: Infiltration, percolation,
through flow, groundwater flow
and surface run off
- Storage: Interception,
surface storage, soil
moisture and groundwater
- Outputs: Evaporation,
transpiration and river
carrying water to the
sea
- Definition of Drainage Basin - the
area of land drained by a river and
its tributaries
- Input: Precipitation
- Factors effecting infiltration
- Intensity of rainfall
- Type of soil or rock
- Height of water table
- Amount of vegetation - more trees = more
interception but also means more roots = more
infiltration
- Time of rainfall
- Angle of slope - steep
= water runs off = less
time to infiltrate
- Intensity of rainfall
- Water balance
- Run off = precipitation - evaporation
+/- changes in storage
- Depends on
months/weather for a
positive/negative water
balance
- Balance between inputs
and outputs in a
drainage basin
- Allows planning and
managing water
supply
- Allows planning and
managing water
supply
- Run off = precipitation - evaporation
+/- changes in storage
- Flooding case studies
- Northern England
- Torrential rain hit Hebden Bridge in July 2012
- over 44mm fell in 3 hours (a
months worth)
- Canal breached its banks flooding the
town centre
- Ground was too saturated to infiltrate the
water causing surface run off
- Ground was too saturated to infiltrate the
water causing surface run off
- over 44mm fell in 3 hours (a
months worth)
- Effects
- Restoration of property took a long
time due to assessments by
insurance companies
- Closure of Sandygate lane as
debris covered the road
- More than 500 homes and
businesses were flooded
- Great Yorkshire Show which
costs £2.2 million to stage was
cancelled
- Great Yorkshire Show which
costs £2.2 million to stage was
cancelled
- Many trees were pulled
down due to current of the
water
- Restoration of property took a long
time due to assessments by
insurance companies
- Responses
- Council provided free cleaning materials
- Council are now working with the
Environmental Agency to prevent any future
flooding by looking at the upper course of
Calerdale
- Engineers and green teams worked until the
early hours of the morning to deal with the
after effects.
- Council provided free cleaning materials
- Torrential rain hit Hebden Bridge in July 2012
- Manila, The Phillipines
- More than half the amount of rain
expected to fall in August fell in under 24
hours - over 250mm
- Many damns began to overflow
- 60% of the city was underwater
- Many damns began to overflow
- Effects
- 19 people died, 9 of which was a family when a
landslide hit shanty houses and others died from
drowning and electrocution
- All businesses have been closed
apart from some convenience stores
- Shortage on supplies
- Shortage on supplies
- Tonnes of debris and mud
left, disease spread by
contaminated water
- Families have been split up by the flood stranding people
- Can't afford insurance so most have lost everything
- 19 people died, 9 of which was a family when a
landslide hit shanty houses and others died from
drowning and electrocution
- Responses
- Tens of thousands of people have
been evacuated by 130 emergency
crewmen
- $765 million is being spent to strengthen and
restore the Manila Bay seawall aswell as the
construction of flood gates and pumping
stations
- US ambassador to the Philippines has provided
$100,000 for disaster relief
- Tens of thousands of people have
been evacuated by 130 emergency
crewmen
- More than half the amount of rain
expected to fall in August fell in under 24
hours - over 250mm
- Northern England
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