Boscastle Floods

16th August 2004

Key words from this case study

Impermeable surfaces – where water cannot soak into the ground and so runs straight over the top e.g. concrete, tarmac and rocks such as slate or clay.

Surface run-off – where water that has not soaked into the ground flows over the surface. This way water enter rivers much faster than if it soaked into the ground.

Saturated – when the ground is so full of water it cannot soak up anymore. This is also when surface runoff occurs.

Causes• Over 60 mm of rainfall (typically a month's rainfall) fell in two

hours.• The ground was already saturated due to the previous two weeks

of above average rainfall.• Boscastle sits in a V shaped valley and has many steep slopes,

and has areas of impermeable slate causing rapid surface run-off.• Boscastle is at the confluence (where tributaries meet) of three

rivers - Valency, Jordan, and Paradise. A large quantity of water all arrived within a short space of time causing the rivers to overflow.

• The flooding coincided with a high tide, making the impact worse.

Effects• The flooding affected 58 properties and 1000 people, with belongings being

destroyed and lost.• 4 properties were demolished, including the visitor centre. • In addition, 84 wrecked cars were in the harbour, with another 32 out at sea. • Damage to buildings and services cost North Cornwall District Council up to £2

million. • A dramatic decrease in tourist numbers immediately after the flood led to the

town being described by business leaders as a ‘tourist ghost town’.• However, when businesses reopened the village was ‘bustling’ with

‘sightseers’.• Despite this, hotel businesses suffered from a decrease in overnight visitors.• However, it could be seen that the flood in Boscastle has benefited the village

economically in the long run.• The benefits include new shops built with insurance money, a new, bigger

visitor centre, a reshaped car park away from the river and a new flood alleviation scheme.

Prevention• In 2005, a new £800,000 flood defence scheme opened in

Boscastle which includes a new, larger culvert on the river Jordan which will be able to carry double the amount of floodwater.

• In August 2006, construction started on the river Valency flood defence scheme.

• In order to increase its capacity the river has been widened and deepened and the lower bridge replaced.

• A new car park has been built which is raised and set back from the river and a new tree management scheme has been introduced to reduce the chances of tree blockage.

• Two new sewing pumps and stations and a new sewer pipe to assist with flood flows have also been introduced.

• Flood defence works together with the regeneration scheme cost £10 million and were officially opened in October 2008.

The new bridge

Cutting out a wider, deeper channel

New culvert for the river Paradise which drains twice as much water as the river

channel used to.