What links ? Prince Charles Gary Rhodes Laurence Llewellyn Bowen Images from BBC

Picture pile of images from BBC News website – created by PICASA

Map produced by MULTIMAP.COM. Mapping produced by Ordnance Survey.

The BOSCASTLE FLOODS 16 th August 2004

BOSCASTLE, North Cornwall

Watch the news footage… Also consider PRIMARY EFFECTS SECONDARY EFFECTS HUMAN CAUSES PHYSICAL CAUSES

DETAILS ON THE FLOOD Go to NCDC site: download PDF leaflet. Have photocopy of the timeline – what happened next ?

Go to NCDC site: download PDF leaflet.

Have photocopy of the timeline – what happened next ?

PHYSICAL CAUSES Three rivers: Valency, Jordan and Paradise, converge on the village. Heavy rain caused by extreme frontal activity. 3 million tonnes of water added to a small drainage basin of just 40 square kilometres. 185mm of rain in just under 5 hours – infiltration excess overland flow Soils saturated from rainfall earlier in the week encouraged overland flow 3 valleys steep and narrow – broader floodplain would have increased hydraulic radius Soils thin on steep slopes due to mass movement Parent rock is old red sandstone: limited permeability Rivers flashy Surrounding vegetation agricultural land: limited interception storage High tide in the bay – restricted rate of exit of floodwater

Three rivers: Valency, Jordan and Paradise, converge on the village.

Heavy rain caused by extreme frontal activity. 3 million tonnes of water added to a small drainage basin of just 40 square kilometres.

185mm of rain in just under 5 hours – infiltration excess overland flow

Soils saturated from rainfall earlier in the week encouraged overland flow

3 valleys steep and narrow – broader floodplain would have increased hydraulic radius

Soils thin on steep slopes due to mass movement

Parent rock is old red sandstone: limited permeability

Rivers flashy

Surrounding vegetation agricultural land: limited interception storage

High tide in the bay – restricted rate of exit of floodwater

HUMAN CAUSES Settlement developed on narrow flood plain where rainfall is often high – now over 1000 residents Tourist season: population more than doubled – vehicles parked in top car park, and higher levels of stock in the shops No flood defences: new ones due in October Narrow bridges – old stone arched design Difficult to establish casualty figures due to transience of population – difficult for emergency services

Settlement developed on narrow flood plain where rainfall is often high – now over 1000 residents

Tourist season: population more than doubled – vehicles parked in top car park, and higher levels of stock in the shops

No flood defences: new ones due in October

Narrow bridges – old stone arched design

Difficult to establish casualty figures due to transience of population – difficult for emergency services

EFFECTS Your own research here…. Here’s a starter: Only 1 casualty (broken thumb) and no deaths 58 properties flooded – 4 demolished 4 footbridges on the Valency washed away (debris dams) 84 cars recovered from harbour, and 32 more ‘lost at sea’…

Your own research here….

Here’s a starter:

Only 1 casualty (broken thumb) and no deaths

58 properties flooded – 4 demolished

4 footbridges on the Valency washed away (debris dams)

84 cars recovered from harbour, and 32 more ‘lost at sea’…

FINAL WORDS Event was 1 in 400 year event. Peak flow of 140 cumecs Water speed in excess of 4m / second – 2 million tonnes (440 million gallons) of water flowed through village causing structural damage Replacement of buildings should be allowed according to report due to return period and preventative works being put in place.

Event was 1 in 400 year event.

Peak flow of 140 cumecs

Water speed in excess of 4m / second – 2 million tonnes (440 million gallons) of water flowed through village causing structural damage

Replacement of buildings should be allowed according to report due to return period and preventative works being put in place.

PAST QUESTION To answer using Boscastle as case study…. With reference to a specific example, explain the physical causes of flooding. You may use a diagram to explain your answer. [6 marks] Or it could have asked you to explain human causes instead….

Useful sources http://www.geographypages.co.uk/asflood.htm http://www.environment-agency.gov.uk http://www.ncdc.gov.uk http://www.geographyinthenews.rgs.org