Geography AS: Boscastle Flood Case Study

Location

Date

Main Cause

Boscastle: Cornwall England

16th August 2004

Remainder of Hurricane Alex

What were the human causes (x6)

Boscastle built in flood prone area

No flood defences

Drainage system didn't have large enough capactiy

Low bridge trapped debris and blocked river

Car park was significant part of flood plain and was tarmacced - no infiltration

Agricultural Land - lack of trees for interception

What were the physical causes of the Boscastle floods? (x8)

The Valley drops 300m in just 6km

185mm rain fell in 5 hours compared to an average of 70 to 90mm for the whole of August

The rock in the area is impermeable

There was a small landslide upstream which blocked the river and allowed it to back up

High tide slowed the river in the village

Boscastle downstream of confluence between 3 rivers: Valency, Paradise and Jordan

The water table was already high

3 million tonnes of water fell in a 21.5km2 drainage basin

What were the effects of the Boscastle floods? (x9)

The Telephone, Gas and Electricity supplies were cut

People were displaced

People were traumatised

115 cars were washed away

58 buildings were flooded

6 buldings and the bridge were destroyed including 4 busineses

The witchcraft museum lost 'irreplaceable' artefacts

Local amenities were silted up

House prices halved

What were the primary responses to the Boscastle floods?

7 rescue helicopters arrived within 90 minutes, rescuing 100 people from buildings

The council closed the village for 10 days whilst buildings were assesed

The GP surgery acted as an emergency centre

Police, fire, ambulance and army services called to the scene

Homeless victims were taken to a village 10 miles away and supplied with food and clothes

What were the secondary responses to the Boscastle flood (x11)

Charity appeal raised £400 000

Flood management increased return period from 1 in 10 years to 1 in 75

Low bridge raised

Culvert

New Sewage System

Valency widened and deepened for efficiency

Vegetation and sediment management scheme

Tree planting

Car park raised and set back

£15 million pay out by insurance companies (some claims unsuccessful)

Youth Hostel and tourist information rebuilt. Shops refurbished