The numbers refer to: - 16 August 2004 - The date of the Boscastle floods - 90 - The amount of rainfall in millimetres that fell in one hour - 3 - The height of the flood wall of water in metres - 4.5 million - The cost in pounds of the flood defence scheme - 0 - The number of lives lost, thanks to the rescue operation

1. Flooding 3 –
Case study UK
Key idea

2. Lesson objectives:
By the end of the lesson you should be able to
•Name an area in the UK that has experienced devastating
flooding.
•Be able to state some of the physical reasons behind the
flooding.
•Be able to state what impacts the flood had on the area and local
people. (Some of you may be able to classify these impacts into
those that were social, economic and environmental, and whether
they are long or short term impacts.)
•Be able to state how people responded to the floods. (You may
consider how effective the response was)
•Explain the measures taken to try to prevent future flooding
events in this area.

4. Poem

5. What happened?
• http://news.bbc.co.uk/player/nol/newsid_41500

6. http://www.metoffice.gov.uk/education/teens/popup/
popup_wboardap_sat_image_boscastle.html

7. Rainfall
The rainfall rate key shows
how the colours in the image
relate to the rate the
rainfall is falling. For
example, the red areas
indicate that rain is falling at
between eight and 16 mm per
hour.
• A line of very heavy rain
starts at about 1 p.m. on the
moors close to Boscastle. It
remains over the area for
about six hours. Rainfall
rates of at least 32 mm per
hour are being measured.

8. Weather chart
• The wind is blowing
anticlockwise about the low
pressure area, so the air is
arriving into Boscastle from a
south-westerly direction. It is a
warm and moist tropical
maritime air mass.
• The line labelled (known as a
trough line) caused very heavy
rain and thunderstorms. A
trough is an area of localised
rain and thunderstorms. A line
of convergence formed near the
coast line, where air moving in
almost opposite directions
collides, this helped to increase
the rate of ascent and produced
very heavy rain.

10. Causes of the flood:
3. Heavy localised rainfall. 89mm of rain fell in an hour.
4. Saturated ground from previous rainfall.
5. Topography of the land – the landscape upstream of
Boscastle acts as a funnel, directing vast volumes of
water into the village. The valley sides are steep
sided.
6. Narrow river channels in the village itself.
Boscastle Harbour

11. Saturated ground.

13. 16 August 2004, 200 millimtetres Cornwall
A summer storm dropped
Boscastle, of rain in
four hours
90 millimetres of rain fell in one hour
The water ran down steel hillsides in to the River
Valency and River Jordan causing two rivers to
burst their banks. The confluence of the two rivers
lies just above Boscastle
A 3 metre high wall of water swept through the
village.
Residents had little time to react.
Cars were swept out to sea
Buildings were badly damaged.
Fortunately, nobody died - thanks largely to a huge
rescue operation involving helicopters.

17. Effects …
• Destruction of houses, businesses and
gardens
Floodwater gushed into houses, shops
and pubs.
• Cars, walls and even bridges were
washed away.
• The church was filled with six feet of
mud and water.
• Trees were uprooted and swept into
peoples' gardens.
• The weight of water eroded river banks,

18. Short Term effects
● Roads were blocked off by the floodwater, making emergency
access difficult except from the air. Even when rescue
helicopters arrived, the valley was only big enough for two to
operate at any one time, prolonging the operation & putting lives
at risk from the still rising flood waters.
● Property was destroyed by debris such as entire trees &
vehicles speeding down the valley at high speed, pulled out
towards the sea by the raging torrent. Buildings were smashed,
especially in the main street where the river channel flows.
● People were trapped in buildings by the floodwater & forced to
seek refuge on the roofs of the buildings & await rescue.
● People were left homeless for the night, so emergency
accommodation had to be set up. Nearby hotels & guest houses
were packed with tourists who had arrived in Boscastle in the
morning & had lost their cars.
● A burst sewage main & damaged buildings made much of
Boscastle inaccessible for health & safety reasons for at least a
few days.

19. Long Term Effects
● Floodwater damaged a great deal of properties.
Possessions were lost, river water & a burst sewage
main spoiled the ground floor of many houses &
thousands of pounds worth of damage was done.
● Repairs had to be made after the damage. This was
very time consuming & costly. Some buildings were
beyond repair & their owners have had to consider
rebuilding from scratch.
● The damage not only affected the residents, but also
insurance companies.
● Boscastle's main industry is tourism. The town was
effectively closed to tourists after the flood, causing
a massive loss of revenue.

21. Human Impacts
There was a huge financial cost to the
floods. This included:
• the rescue operation - involving
helicopters, lifeboats, and the fire
service.
• the loss of 50 cars
• damage to homes, businesses and land
• a loss of tourism, a major source of
income for the area

22. Other key impacts on Boscastle
and its inhabitants
• environmental damage to local wildlife
habitats
• coastal pollution caused as debris and fuel
from cars flowed out to sea.
• long-term disruption to the village, as a major
rebuild project had to be carried out.
• long-term stress and anxiety to people
traumatised by the incident.

23. Responses
Immediate
• Emergency services responded speedily
and efficiently
• Helicopters airlifted 80 people to safety
from roof tops

24. Medium and long term responses
• £800,000 flood defence scheme
completed in Boscastle by April 2005
• Engineers investigating future flood control
works on River Valency

25. A £4.5m scheme to improve flood defences.
Boscastle main car park.

26. The scheme stretches along the valley, incorporating
drainage, sewerage systems and land re-grading.
Boscastle main car park.

28. The river bed is being deepened by six feet to
accommodate more water volume in times of flood.

29. Boscastle car park is being raised in height. This will
stop the river from bursting it’s banks so easily.

30. This drain allows water to run into the lower
section of the river quickly.

31. • A concrete culvert
running behind a row
of eight cottages. This
converts to a concrete
pipe running down a
road to an outfall into
the river Valency,
downstream of the
main bridge through
the village

32. The river channel is being made deeper and
wider so that it can accommodate more water.
The lower section of the village.

33. New sewerage systems are being put in place.
The lower section of the village.

34. Bridges that hindered the drainage of the floodwater
are being replaced by stronger bridges that are less
likely to get blocked.
Notice attempts to draw
in much needed custom.
The lower section of the village.

35. The new lower bridge is
an important part of the
£4.6 million flood
defence scheme, as it
spans a channel specially
widened to help reduce
flood risk to local
residents, homes and
businesses near the
harbour. It will carry
traffic as well as
pedestrians and will
replace the existing
bridge
source

36. Many buildings have indicators to show the height of
the flood water.
The core of the village.

37. Plenary
• What is the significance of these
numbers?
• 16
• 90
• 3
• 4.5 million
• 0