Climate Change and the Climate Change and the

Implications for the Implications for the

Management of Coastal Management of Coastal

LandslidesLandslides

James HoughtonJames Houghton

Senior Geotechnical EngineerSenior Geotechnical Engineer

Isle of Wight CouncilIsle of Wight Council

Outline

• Background to landsliding on the Isle

of Wight

• Current management strategies

• Specific projects aimed at reducing

landslide risk

The Isle of Wight CoastlineThe Isle of Wight Coastline

--Complex and VariedComplex and Varied

The UndercliffThe Undercliff

The Undercliff

12km 500m

Simplified Ventnor Landslide Model

Landslip at BonchurchLandslip at Bonchurch

Loss of Road at NitonLoss of Road at Niton

GIS Map Data, Ventnor Undercliff

Ordnance Survey Base map

Aerial photograph

Landslide Susceptibility in the Undercliff

Mean Monthly Effective Rainfall

Change Scenarios at Ventnor

From Halcrow, 2001

IWCCE Key Responsibilities

• Shoreline Management & Coast Protection

• Coastal, landslide and cliff monitoring and management

• Ground stability engineering

• Planning liaison over coastal, geotechnical and

environmental issues

• Harbour management

• Dissemination of information and public relations through

the Isle of Wight Coastal Visitors Centre

Undercliff Landslide Management Strategy

Management Committee

Planning control

Isle of Wight Undercliff

Landslide Management Strategy

Planning guidance map

Codes of goodpractice

Coastalprotection

Drainage

Engineering measures

Building control Monitoring

Early warning

Forecast

Lossmitigation

(since 1992)

Ongoing ground movement

monitoring,

European funded projects, etc.

5) Further monitoring and research

E.g. The Graben, Newport Road,

Upper Ventnor

4) Avoidance of seriously affected

areas

Advice to homeowners leaflets

(periodically updated & reissued)

3) The control of water in the ground

Opening of Coastal Visitors’ Centre

in 1998

2) Public education and information

Construction of the Castlehaven

coastal protection and land drainage

scheme

1) Engineering measures (coastal

protection works and drainage etc.)

Action Example

Isle of Wight Undercliff

Landslide Management Strategy

1) Engineering Measures

Castlehaven

• The Coastal Centre is open to the public daily providing displays and information about the coastline of the Isle of Wight, including geology, environment, archaeology, coastal defences and landslides.

• The Centre also runs a varied programme of coastal based education.

2) Public education & information

The Coastal Visitors Centre, Ventnor

www.coastalwight.gov.uk

3) Control of water in the ground:

Advice to homeowners…

(New leaflet issued October 2004)

The Graben, Newport Road, Upper Ventnor

4) Avoidance of seriously affected areas…

5) Geotechnical Monitoring…

The Monitoring NetworkThe Monitoring Network

•Consists of approximately 100 sensors.

•Network constantly being expanded.

• Includes inclinometers, tiltmeters, piezometers,

extensometers and settlement cells, as well as

numerous telltales and other low-tech monitoring

points.

•Readings taken at a variety of periods ranging

from once a month to every three minutes.

Coastal Defence Policy

IW Shoreline Management

Plan

Isle of Wight North East Coastal Defence Strategy Study

Sandown Bay and Undercliff Coastal Defence Strategy Study

West Wight Coastal Defence Strategy Study

Implementation Plan

5 Yearly Review

100 Year Timeframe

Landslide Management Strategies

Applicable to Climate Change (from Lee

and Jones, 2004)

• The use of no regret or low regret options

• Adaptive management

• Delaying action

• Delay and buy time

• Changing the land use / site abandonment

• Contingency planning

• Making allowance for climate change in engineering

schemes

Completed RevetmentCompleted RevetmentCompleted RevetmentCompleted Revetment

Siphon drain Line A

Siphon drain Line B

Electro-pneumatic drain -

Line DSiphon drain Line C

Siphon drain Line E

Siphon drain Line G

Siphon DrainSiphon DrainSiphon DrainSiphon Drain®®®® Solution: LayoutSolution: LayoutSolution: LayoutSolution: Layout

Siphon drain Line F

Siphon drain Line H

DRAINAGE CONNECTIONS

Compressor

Chamber

Outfall at Castlehaven

Headland

Local & Regional:Local & Regional:• Standing Conference on Problems Associated with the Coastline (SCOPAC)

• The Solent Forum

• Isle of Wight Estuary Partnerships

• Schemes of Management for European Marine Sites

• South-East Climate Change Partnership

National:National:• Local Government Association Coastal Special Interest Group (LGASIG)

• Chairmen of the Coastal Groups of England and Wales

• Technical Advisory Group (TAG)

TransTrans--National:National:• Arc Manche

• Conference of Peripheral Maritime Regions of Europe (CPMR) and the

Islands Commission of CPMR• World Landslide Networks e.g. United Nations International Strategy for

Disaster Reduction (UN ISDR)

Networks & GroupsNetworks & GroupsNetworks & GroupsNetworks & Groups

Eurosion

(2002-2004)

EcoEnhance

(1999-2001)

PROTECT –

PRediction

Of The

Erosion of

Cliffed

Terrains

(2001-2004)

Response – Responding to

the Risks from Climate Change (2003-2006)

Coastal Change, Climate

and Instability (1997-2000)

A Life Environment

‘Success Story’

RESPONSERESPONSE

Responding to the risks from climate change

– Developing sustainable strategies for the management of natural hazards in

coastal areas taking account of the impacts of climate change.

supported by the European Commission's

LIFE Environment Programme

www.coastalwight.gov.uk/response.html

• 2003 – 2006 (3 years)

• 5 Coastal Study Areas

• 9 Project Partners