Flooding in Boscastle16th August 2004

Map of Boscastle.

Aerial Photo.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

The Boscastle Drainage Basin

Rainfall in this area is high so...

The valley sides are steep so …

Trees have been cut down above the river. This could make flooding worse because...

The mouth of the river is narrow so…

Settlements have been built upstream. This could mean…

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

The narrow valley can be appreciated when looking upstream from the harbour.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Causes of the flood:

1. Heavy localised rainfall. 89mm of rain fell in an hour.2. Saturated ground from previous rainfall.3. 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.

4. Narrow river channels in the village itself.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Saturated ground.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

The ground is saturated so any further rain can’t be absorbed so..

The river reaches bankful stage. Any further water will lead to…

The discharge is..

The velocity is.. The river is discoloured because..

The carrying capacity of the river has increased because..

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

In an operation lasting from mid-afternoon until 2:30 AM, a fleet of seven helicopters rescued about 150 people clinging to trees and the roofs of buildings and cars. Amazingly, no major injuries or loss of life were reported. About 90% of Boscastle’s economy is tourism and about 2/3 of this income usually occurred during the school holidays.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Impacts of the flood:

•Around 115 cars were washed into the sea•Several boats were also lost, •6 buildings were destroyed•Loss of tourist trade•Fall in house prices•B3263 road was blocked by flood waters•businesses destroyed including visitor centre•Economic damage estimated 2006 = £300 million•Seven helicopters rescued about 150 people•No major injuries or loss of life were reported. •About 90% of Boscastle’s economy is tourism based and about 2/3 of this income usually occurred during the school holidays.•House prices fell as houses termed flood risks

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

How have decision makers responded?

A £4.5m scheme to improve flood defences.

Boscastle main car park.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

The scheme stretches along the valley, incorporating drainage, sewerage systems and land re-grading.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

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

The river lies here.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

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

Boscastle flood defences.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

The river channel is being made deeper and wider so that it can accommodate more water.

The lower section of the village.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

New sewerage systems are being put in place.

The lower section of the village.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

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.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

So what’s been done to mitigate against flood reoccurrence?

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

.The narrow river Valency channel has now been widened

The channel has been deepened

The river banks have been raised

The bridge has been raised and widened

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Reminders of the flood remain throughout the village.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Many buildings have indicators to show the height of the flood water.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

Whether flooding is prevented remains to be seen...

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.

PROGRESS CHECK QUESTIONS:

Must… Could..

What were the causes of the Boscastle flood?

How did people make the Boscastle flood worse?

Name 5 effects of the Boscastle flood. Make 2 lists to show long term and short term effects of the Boscastle flood.

How can the risk of flooding be reduced?

List 4 ways that flooding can be reduced. For each, say how effective the method would be.

MUST: Annotate images and diagrams to show the causes and effects of the Boscastle flood.SHOULD: Categorise the effects of flooding. Identify ways that flooding can be reduced.COULD: Evaluate methods of flood protection and suggest alternative methods.