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West Wight Coastal Flood andErosion Risk Management Strategy
MAIN STRATEGY DOCUMENT
DRAFT FOR CONSULTATION
MARCH 2016
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This Strategy was produced for Isle of Wight Council with technical
assistance from the engineering and environmental consultantCAPITA | AECOM.
This project was funded by the Environment Agency from
Flood and Coastal Risk Management Grant-in-Aid.
Photos (C) Isle of Wight Council 2016 (& pages cover, 56, 95, 128, 163 & 168 courtesy of S.Lee)
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3West Wight Coastal Flood and Erosion Risk Management Strategy
CHAPTER 1
INTRODUCTION8
Contents
12 Strategy objectives
13 The shoreline management planning hierarchy
14 The need for a strategic approach
16 Purpose and structure of this document
17 Supporting information
CHAPTER 2 WHAT IS AT RISK IF WE DO NOTHING?
19
21 Why we need the Strategy - what is at risk ifwe 'Do Nothing'
22 Sea level rise and increasing risk
CHAPTER 3 HOW THE STRATEGY HAS BEEN DEVELOPED
24
26 Overview of the study area- key features, issues and opportunities
26 Coastal processes overview - wave, tides,sediment transport
GLOSSARY AND ACRONYMS6
CHAPTER 4 OVERVIEW
48
50 A phased approach to management based on risk
52 Links with the planning process and redevelopment
52 Environmental impacts summary
28 Potentially contaminated land
31 Environment and heritage designations
31 Stakeholder engagement- understanding what people want from the coast
32 Summary of the existing defences33 Option development
35 Strategy Management Zones
43 Strategic Options
45 Strategic Option Appraisal
CHAPTER 5
STRATEGY MANAGEMENT ZONE 1 56
58 Baseline - what would happen if we did nothing?
61 Strategy preferred option - commentary
Needles Headland
Fort Redoubt to southern limit of Totland Bay
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4 West Wight Coastal Flood and Erosion Risk Management Strategy
CHAPTER 11 FUNDING
156
CHAPTER 9
STRATEGY MANAGEMENT ZONE 5 110
112 5a Baseline - what would happen if we did nothing?
117 5a Strategy preferred option - commentary120 5b Baseline - what would happen if we did nothing?
125 5b Strategy preferred option - commentary
Gurnard and Cowes Headland
Gurnard Luck to Cowes Parade
CHAPTER 12 WHAT NEXT?
164
CHAPTER 6 STRATEGY MANAGEMENT ZONE 2
64
66 Baseline - what would happen if we did nothing?
69 Strategy preferred option - commentary
Totland and Colwell Bays
Southern limit of Totland Bay to Fort Victoria
CHAPTER 7
STRATEGY MANAGEMENT ZONE 372
74 3a Baseline - what would happen if we did nothing?
79 3a Strategy preferred option - commentary
86 3b Baseline - what would happen if we did nothing?
91 3b Strategy preferred option - commentary
94 3c Baseline - what would happen if we did nothing?
99 3c Strategy preferred option - commentary
Yarmouth and Western Yar
Yarmouth coast (Fort Victoria to Port la Salle) and theWestern Yar valley (including Freshwater Bay)
CHAPTER 8
STRATEGY MANAGEMENT ZONE 4
102
104 Baseline - what would happen if we did nothing?
107 Strategy preferred option - commentary
Newtown Coast
Bouldnor Cliff to Thorness Bay (including Newtown Estuary)
CHAPTER 10
STRATEGY MANAGEMENT ZONE 6128
130 6a Baseline - what would happen if we did nothing?
135 6a Strategy preferred option - commentary
140 6b Baseline - what would happen if we did nothing?
145 6b Strategy preferred option - commentary
148 6c Baseline - what would happen if we did nothing?
153 6c Strategy preferred option - commentary
Cowes, East Cowes and the Medina
Cowes Parade to Old Castle Point, East Cowes
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5West Wight Coastal Flood and Erosion Risk Management Strategy
SMZ locations
Reproduced from the Ordnance Survey digital data with the permission of the controller HMSO. © Crown copyright and database rights 2016 Ordnance Survey 100019229
SMZ 6
SMZ 1
SMZ 5
SMZ 3
SMZ 2
2 kilometresN
SMZ 3
SMZ 4
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6 West Wight Coastal Flood and Erosion Risk Management Strategy
Glossary and Acronyms
Baseline
Denes an existing condition/situation (usually Do Nothing) against
which options or scenarios are compared.
Benets
The savings (damages avoided) delivered by implementing strategy
options.
Broader Outcomes
Rather than solely considering ood and coastal risks, the Strategy
has taken account of other benets to the community such as
regeneration, tourism, recreation, amenity and coastal accessopportunities.
Costs
The amount of money required to implement the strategy options.
Do Minimum
A management option dened as the minimum amount of action or
intervention necessary to deliver the legal requirement or sustain thestandard of service of the asset.
Do Nothing (No Active Intervention)
A management option dened as taking no action whatsoever; where
there are existing defences, do nothing assumes that no furthermaintenance or repair work is undertaken.
Grant in Aid
Money coming from the central government to fund a coast protectionof ood protection scheme.
HTL (Hold the Line)
A policy with an overarching intent to build or maintain coastal defencesso that the position of the shoreline remains where itcurrently is.
Maintain
A management option in which maintenance of the existing defencesis undertaken. This option does not change the defence or its
performance, but simply maintains it in good working order or restoresit to its previous condition in the event of a breakdown.
MR (Managed Realignment)
Allowing the shoreline to move naturally, but managing the processto direct it in certain areas. This is usually done in low-lying areas,but may occasionally apply to cliffs.
ODU (Option Development Unit)
A section of the coastline in which local scale options to manage ood
and erosion risk are developed.
Partnership Funding
This describes the way coastal defences are often paid for wherevarious "partners" have input into the project. Typically this refers to jointfunding between government and private sources.
Potentially contaminated land
Land potentially containing substances in or under the land which couldpollute controlled waters or cause signicant harm to other receptors
such as humans, animals or the environment.
Present Value
An economics term which refers to the current worth of a future sumof money.
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Priority Schemes
The initial works required following the Strategy to address ood
and erosion risk in key areas.
Property Level Protection (PLP)
Flood mitigation measures applied to individual properties thatreduce the risk of ooding on a property level (i.e. door ood
defenders etc).
Residual li fe
The time left (typically in years) that a defence structure is expectedto be able to provide ood and erosion protection before it comes
to the end of its service life. The residual life is estimated from adefence condition survey and assumes that no maintenance workswill be carried out in the future.
Scheme
A measure, or combination of measures, undertaken to increase
the level of protection against ooding and/or erosion to a local area(e.g. a new oodwall structure).
SMP (Shoreline Management Plan)
A high-level non-statutory planning document which providesa broad scale assessment of the risk associated with coastalprocesses and presents the a long-term policy framework to reducethese risks to people and the developed, historic and naturalenvironment in a sustainable manner. The Isle of Wight SMP2 waspublished in 2010 and approved in 2011.
SMZ (Strategy Management Zone)
A group of units (ODUs) with similar characteristics in whichoverarching, wider scale options to manage the ood and
erosion risk are developed.
Standard of Protection (SoP)
The level of ood risk that a coastal defence structure is designed to
protect against. For example, a defence structure with a 1:100 yearSoP indicates that the structure will protect against ooding from a ood
event which typically occurs once every 100 years.
Sustain (e.g. the standard of protection)
This is a ood risk management term which refers to options that keep
pace with change and potential increases in risk in the future (i.e.from climate change and sea level rise). This is achieved by raising orupgrading defences in the future to sustain the standard of protection.
Abbreviations
STRATEGY LANDOWNERSHA Highways AuthorityPO Private Ownership
ENVIRONMENTAL DESIGNATIONSSPA Special Protection AreasSSSI Sites of Special Scientic Interest
SAC Special Areas of ConservationSAM Scheduled Ancient MonumentsNNR National Nature ReserveLNR Local Nature Reserve
ENVIRONMENTAL ASSESSMENTSWFD Water Framework DirectiveQRA Qualitative Risk AssessmentHRA Habitats Regulations AssessmentSEA Strategic Environmental Assessment
OTHERCAPITA/AECOM Environmental and Engineering Consultants
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i n t r o
Chapter 1
intro
IntroductionSett ing the scene
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10 West Wight Coastal Flood and Erosion Risk Management Strategy
Introduction
The Isle of Wight Council (IWC) and the Environment Agencywith Capita | AECOM engineering consultants have developed
a Coastal Flood and Erosion Risk Management Strategy.
The West Wight Coastal Flood and Erosion Risk ManagementStrategy recommends the preferred strategic approaches formanaging coastal ood and erosion risk for an 84km frontage of the
Isle of Wight coast running from Freshwater Bay clockwise round toOld Castle Point, East Cowes (see gure overleaf).
The Strategy frontage features a wide variety of natural,rural and urban landscapes. The frontage includes sheltered
estuarine environments of the Western Yar, Newtown estuary andthe Medina, the bays of Freshwater, Totland, Colwell, Thornessand Gurnard, the headlands around Cowes, and then the morerugged exposed open coast around the Needles.
Three of the Island's largest urban areas are within the Strategyfrontage; Cowes, East Cowes and Newport (key employment
centres). Totland, Yarmouth and Freshwater are the main settlementsin the west of the Island, also all located on the coast.
The Strategy frontage is home to a rich variety of important habitatsand species and has a wealth of internationally, nationally and andlocally important nature conservation sites along the majority of itscoast and coastal waters. These include European Natura 2000sites that are protected by international legislation as well as national
designations. Many of the current settlements on the Island arehistoric, with 32 Conservation Areas and almost 2,000 Listed Buildings.
In a planning context the Isle of Wight is unique, being an islandwith a large proportion of environmental designations, a coastaland maritime economy, and a fundamental reliance on ferry portsand coastal roads as its key strategic transport links. Large parts ofthe area are designated as an Area of Outstanding Natural Beauty
(AONB) and much of the coastline is designated Heritage Coast.
With such a diverse coastline and range of facilities, tourism is a keyindustry for the Isle of Wight. Residents and visitors are well servedby a number of ferry routes with East Cowes and Yarmouth hostingtwo of the three vehicle ferry links to the Isle of Wight, plus a keypassenger ferry terminal in West Cowes.
There is a wide range of existing coastal defences around the WestWight frontage which help prevent erosion and reduce ood risk.
However many of these aging defences were built in times of greatereconomic prosperity and the future maintenance or replacementof these structures provides a signicant problem in these more
challenging economic times. National 'Grant in Aid' funding isavailable to help fund defence works in the areas most at risknationally. However the outcomes on which this public 'Grant in Aid'funding is calculated and administered are heavily focussed aroundprotection of residential communities, rather than businesses, or toprovide tourism or recreational benets.
intro
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Strategy Frontage
KEY
Strategy Frontage
Land
Sea2 kilometres
N
The Solent
East Cowes
West Cowes
Totland
Yarmouth
Newtown
Newport
Gurnard
Freshwater
Bay
The Needles
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12 West Wight Coastal Flood and Erosion Risk Management Strategy
There is therefore a realisation that future public investment indefences will have to be rationalised and prioritised in key areas.However, as recognised in the development of the Strategy, thereare signicant opportunities to help pay for new defences through
a partnership approach, a new approach to funding required bynational government. For example, working with developers and thepotential beneciaries of future schemes to fund future defences,
and contribute to broader outcomes for communities at risk.This kind of approach will be key to the delivery of the Strategy.
For further information about the Isle of Wight please visit
www.iwight.com
Strategy Objectives
The aim of the West Wight Coastal Flood and Erosion RiskManagement Strategy is to reduce risks to people, the developedand natural environment from ooding and coastal erosion through
the development and implementation of a sustainable Strategy thatencourages provision of technically, economically and environmentallysound management measures.
The objectives were enshrined in the Strategy development processand were key considerations in the appraisal of potential managementoptions. Given the wide range of objectives, and the competing
interests of the coast, it is not possible for the Strategy to meet anddeliver all of these aims. However, it was important that the Strategyseeks to facilitate as many of these as possible. The primary (musthave) objectives are listed below:
Primary objectives
• To build on the work of the Isle of Wight Shoreline ManagementPlan 2, 2010;
• To identify the consequences of implementing the preferred Policiesfrom the IW SMP2, and to seek and select the most appropriateand achievable methods to do so;
• To determine the optimum economic level of coastal oodand erosion protection for the West Wight through assessmentof options;
• To provide a co-ordinated approach between the authorities andorganisations managing the coastline;
• To rene the understanding of coastal ooding and erosion risks topeople and the developed, historic and natural environments using
the latest information;• To balance the needs of people and the environment, in a dynamic
coastal environment with ood, erosion and landslide risks;
• To identify any required Schemes, including their location, timing,feasibility, costs, benets and associated Partnership Funding
scores and Outcome Measures;
• To consult with the community to seek acceptable and achievablemethods to implement the IW SMP2 Policies;
• To identify the operating authority or landowners responsiblefor new and existing infrastructure and begin work with them todevelop proposals;
• To identify the requirements and opportunities for nancialcontributions for any proposed schemes, in line with PartnershipFunding requirements;
• To comply with environmental legislation and identify opportunitiesfor environmental enhancement, allowing where possible the
WITH THE MAJORITY OF COMMUNITIES ANDFEATURES OF INTEREST SITUATED AROUNDTHE COASTLINE, COASTAL FLOOD AND EROSIONPRESENTS A SIGNIFICANT RISK. WITHOUTACTIVELY IMPLEMENTING MEASURES TO MANAGETHESE RISKS IN ROBUST AND STRATEGIC WAYS,THERE WILL BE OVER 4,000 PEOPLE AND 1,500
PROPERTIES AT INCREASED RISK BY 2115.
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natural process and evolution of the shoreline;
• To consider opportunities for broader outcomes linked to initiativessuch as regeneration, development, tourism, recreation andamenity; and
• To dene and prioritise an implementation plan of technically,economically and environmentally sound and sustainable proposalsfor managing coastal ood and erosion risks over the 100 year
appraisal period.
The Shoreline Management Planning Hierarchy
The following section outlines how the Strategy ts into the coastal
management hierarchy in the UK and outlines the approach todeveloping the draft strategic management options for consultation.
The Shoreline Management Plan – sets the policy
Shoreline Management Plans (SMPs) sit at the top of the hierarchyof plans for managing coastal ooding and erosion. A Shoreline
Management Plan (SMP) is a high-level non-statutory planning
document which provides a large-scale assessment of the risksassociated with coastal processes and presents a long-term policyframework to reduce these risks to people and the developed, historicand natural environment in a sustainable manner. An SMP aims tomanage risk by employing a range of methods which reect both
national and local priorities, to:
• Reduce the threat of coastal ooding and erosion to people andtheir property; and
• Benet the environment, society and the economy as far
as possible, in line with the Government’s ‘sustainabledevelopment principles ’.
The Isle of Wight Shoreline Management Plan (2011) presents theshoreline management policies for the Strategy study area. Given theurban areas, and the potential threat of erosion and coastal ooding,
the policy for a signicant part of the frontage is to ‘Hold the Line’ for
Shoreline Management Plan(Identies policies to manage risks)
Coastal Strategy(Identies appropriate Schemes
to implement the policy)
Local level risk reduction(Scheme construction, adaptation,
ood warning, property level protection)
The Coastal Management Hierarchy
the coming century. This policy does not necessarily mean defenceswill be built or maintained in these areas, as funding (especially publicfunding) is often a limitation, however if there is available fundingthis policy is recommended to robustly manage the future risks.This policy can also mean it is appropriate to continue to defend theshoreline with private defences. In order to maintain key habitats andnatural environment there are also signicant areas of the frontage
where the policy is to allow natural process to continue ('No Active
Intervention', or do nothing). In local appropriate areas a 'ManagedRealignment' Policy has been recommended in order to helpbalance habitat losses created by continuing to defend the coastlineelsewhere.
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The need for a strategic approach
Coastal strategies sit at the next tier in the hierarchy and it is the roleof strategies to identify the appropriate scheme or ood risk mitigation
option for implementing the SMP policies. The Strategy will review theSMP policies in more detail to ensure these high level policies remainappropriate at the local scale.
The Strategy considers how ood and erosion risk is likely to
change in the future in response to changes in climate and developssustainable and robust options to manage the risks associatedwith coastal ooding and erosion. This approach ensures that
technically feasible, environmentally acceptable and economicallyviable options are recommended, to reduce the risks from coastalooding and erosion to people, their properties and the environment.
This also ensures that the options are compatible with the preferredmanagement strategies of adjacent areas. The Strategy is alsorequired in order to gain approval for future schemes, and helpssecure public Grant in Aid monies to contribute to the costof defences.
Without such an approach, it is likely that future coast defence workswould be managed on an ‘ad-hoc’ or reactive basis which would leadto poor cost efciency and a general increase in the ood and erosion
risk over time. A strategy is also important in providing an integratedapproach to the management of our coastline and prioritising risksand responses. The holistic wider-level thinking behind strategydecisions ensures that the management options implemented in one
area do not increase the ood and erosion risk in adjacent areas, andthat opportunities to deliver wider benets are not missed.
The outputs
Following a strategy, a variety of outputs can result depending onthe level of risk and the preferred options put forward. To deliver thestrategic management option it may be necessary to implement works
to address coastal ood and erosion risks. In other areas, where
little is at risk, the future action may be to ‘do nothing’ and let naturalprocesses continue. There may also be actions such as monitoring,setting planning policy and further detailed studies required in order togather additional evidence to make robust future decisions.
Where schemes are required, a further element of work comparingthe various options in more detail is then undertaken to select thepreferred measures, methods and optimal standard of protection.The detailed business case will be developed to gain funding andapproval. On approval of the scheme, detailed design is carried outand then the works can be implemented the ground. Schemes do notonly deliver raised defences such as new sea walls; other options
Hold the Line Policy
Preferred option:Sustain a minimum
1:100 year standard of
protection against ooding
Implement:
a new sea wall raising the
existing defence level
I N C RE A S I N G DE T A I L
How the Strategy ts in the management of coastal ood and erosion risk
EXAMPLE OUTPUT LEVEL
SMP
Strategy
Scheme
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15West Wight Coastal Flood and Erosion Risk Management Strategy
The high level coastal management polic ies being examined by thisStrategy: set by the Isle of Wight Shoreline Management Plan, 2011
2 kilometresN
The Solent
East Cowes
West Cowes
Totland
Yarmouth
Newtown
Newport
Gurnard
Freshwater
Bay
The Needles
KEY/POLICY
Hold the Line
Hold the Line (2005-2025), then No Active Intervention
Hold the Line (2005-2025), Managed Realignment(2025-2055), then No Active Intervention
Hold the Line (2005-2055), then No Active Intervention
Land
No Active Intervention
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16 West Wight Coastal Flood and Erosion Risk Management Strategy
include ood warning systems, property level protection, adaptation
options and environmental enhancement.
Purpose and structure of this document
This document presents the draft Strategy for public consultation andsets out the recommendations and preferred options for managingcoastal ood and erosion risk along the study frontage for the next
100 years. In developing the Strategy, an understanding of thepresent day risk has been developed along with how it might changein the future and the ways in which we can manage and adapt tothese changes. Specically, this document includes:
Chapter 2 – Understanding what is at risk
• A summary of what is at risk now and in the future (dening
the baseline). Including an assessment of what would happen ifwe ‘do nothing’ and how the risks change over time as a result of
predicted climate change and sea level rise. This sets the contextfor why we need the Strategy.
Chapter 3 – Developing the Strategy
• Overview of the study area - Key Features, Issues andOpportunities. This identies the key aspects and characteristics
of the study area which the Strategy has considered. This includes:coastal processes, potentially contaminated land, the environment,stakeholder engagement and aspirations, and a summary of the
existing defences.• A descript ion of the option development and appraisalprocess. Including a summary of how the strategic optionswere developed and appraised considering their economic andenvironmental sustainability.
Chapter 4 – Strategy overview
• A summary of the Strategy – including the phasing of options overtime based on the level of risk.
• Links wi th planning and redevelopment – including how theStrategy has been developed to take account of these key issues.
• Environmental Impacts Summary – including how the Strategyhas been developed to ensure that it is environmentally robust and
sustainable..
Chapters 5 to 10 – Management Zones 1 – 6
• The preferred options by Management Zone. An area by areasummary of the Strategy options being put forward to reducefuture coastal ood and erosion risk. Urgent priority works are also
identied within this section.
Chapter 11 - Funding
• An overview of funding sources for coastal schemes.
• A summary of the priori ty schemes arising f rom the Strategy.
Chapter 12 – What next?
• A summary of what happens next and how you can ndout more.
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Supporting Information
This document provides a concise summary of the Strategy ndings
and proposals. For more detailed information please refer to thefollowing Appendices.
These are available online at www.coastalwight.gov.uk
Appendix A
Defence Condition Review
Appendix B
Desktop Contaminated Land Review
Appendix C
Coastal Processes Review
Appendix D
Flood Modelling and Risk Mapping
Appendix E
Stakeholder Engagement Feedback
Appendix F
Economic Appraisal
Appendix G
Strategic Environmental Assessment Report
Appendix H
Habitats Regulations Assessment Appropriate Assessment
Appendix I
Water Framework Directive Summary Statement
Appendix J
Option Development and Appraisal
The two Risk Management Agencies in the Strategy area are theIsle of Wight Council and the Environment Agency. For furtherinformation please visit their websites below:• www.iwight.com
• www.gov.uk/government/organisations/environment-agency
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Newport Quay Flooding
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r i s
k s
Chapter 2
risks
What is at risk if
we do nothing?Why do we need the Strategy?
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20 West Wight Coastal Flood and Erosion Risk Management Strategy
Sample of the key assets at risk of erosion and ooding*
*Flooding extent from an event with a 0.5% chance of occurring at 2115 assuming current defences are in placeReproduced from the Ordnance Survey digital data with the permission of the controller HMSO. © Crown copyright and database rights 2016 Ordnance Survey 100019229
2 kilometresN
KEY
1
23
4
5
6
7
8 9
10
Erosion Area
2115 - 1:200 year (0.5%annual chance) ood event
1. Totland at risk of erosion
2. Yarmouth at risk of ooding
and erosion
3. Bouldnor Road
at risk of erosion
4. Freshwater
at risk of ooding
5. Freshwater Bay
at risk of ooding
and erosion
6. Gurnard Luck
at risk of oodingand erosion
7. Gurnard - Cowes
at risk of erosion,landslide reactivationand ooding
8. Cowesat risk of ooding
and erosion
9. East Cowesat risk of ooding
and erosion
10. Newport at risk of ooding
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21West Wight Coastal Flood and Erosion Risk Management Strategy
Time Horizons
2015 2025 2055 2115
Residential properties (ood risk) 202 225 244 359
Commercial properties (ood risk) 276 306 316 336
Total properties at risk of ooding 478 531 560 695
Total properties at risk of erosion(Residential and Commercial)
0 6 347 1404
Total Value of Assets at Risk
(£M cash)£97M £115M £227M £472M
Why we need the Strategy - what is at ri sk if we ‘Do Nothing’?
Gaining an understanding of the ood and erosion risk along the
shoreline is imperative in order to dene a baseline for developing
the coastal strategy. It allows comparisons to be made between thepotential management options. The baseline was established byconsidering a ‘Do Nothing’ scenario.
The ‘Do Nothing’ scenario is dened as: “Where there is no further
intervention of any kind, including no emergency response or warningsystem, and nature is allowed to take its course. Where there are
assets present or where maintenance activities or other interventions
are carried out, the option will be to withdraw all activities".
In essence, the ‘Do Nothing’ scenario represents a hypotheticalsituation whereby all existing defences are abandoned in termsor maintenance or repair, and no remedial or additional protectionworks are carried out. In addition, adaptation to sea level rise or otherclimate change responses are not addressed.
Summary of people and assets potentially at risk of coastal ooding
and erosion over the coming century
Over 1,100 residential properties
Over 300 commercial properties (shops, ofces etc.)
Over 100 warehouses
38 industrial sites
46 public buildings
31 restaurants/pubs/cafes
2 supermarkets
142 leisure facilities
13 car parks
28 electricity sub-stations
1 school
3 ferry terminals linking the island to the mainland
Multiple marinas
Numerous coastal footpaths
Major roads including the A3054 and A3055
Heritage assets and listed buildings
Environmentally designated habitats
Coastal waterbodies
Local and national nature reserves
Country parks
Tens of kilometres of coastal promenades, slipways
N22 cyclepath between Freshwater and Yarmouth
Beaches used by residents and as visitor attractions
Properties at risk of ooding and erosion over the coming century if we 'Do Nothing'.
Based on 1:200 year (0.5% annual chance) ood event.
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22 West Wight Coastal Flood and Erosion Risk Management Strategy
What is meant by ood risk?
The likelihood that a certain level of ooding will occur is described as
‘ood risk’ or the ‘chance’ that a location will ood in any once year.
This risk can be expressed in terms of an average return period in years.For example a large event occurring on average once per century maybe referred to as a 1 in 100 year event (there is a 1% chance of a ood
of this scale in any one year). An extreme event which typically onlyoccurs once in any 200 year period is termed a 1 in 200 year event
(this means there is a 0.5% annual chance of an event of this scaleoccurring), and so on.
The chance is related to the scale of the ooding. In any one year a
large (1 in 200 year) ood event has statistically less chance of
happening than a smaller 1 in 100 or 1 in 50 ood event. It is important
to understand that a 1 in 100 chance of ooding does not mean that a
ood will only happen once every 100 years. The chance remains the
same every year. Throughout this document the scale of ood risk is
described in terms of the average return period in years.
When protecting against ooding, the risk level that a schemeprotects against is described as the Standard of Protection (SoP).For example, if a scheme provides a 1:100 year SoP it means there is ahigh degree of certainty that it will prevent ooding from all events up to
this magnitude.
What is meant by erosion ri sk?
For the purposes of the Strategy, properties or assets at risk of erosionare those which could potentially be lost to the sea through shorelineretreat or landslide. The baseline risk has been estimated assuming
no further works are done to repair or maintain defences whichcurrently provide protection.
Understanding the potential erosion risk under a hypothetical‘Do Nothing’ scenario’ is important for comparing the relative meritsof options to maintain or improve protection.
For the purpose of the Strategy, the risks posed by coastal ooding
and erosion over the next 100 years have been established usingEnvironment Agency approved numerical ood modelling and
updated Shoreline Management Plan erosion predictions (toaccount for Environment Agency guidance change on sea level riseallowances). It should be noted that even with the existing defences inplace; future ood risk will increase signicantly due to climate change
and rising sea levels.
Through determining the present and future ood and erosion
risks under a ‘Do Nothing’ scenario, the properties, features,
assets and key infrastructu re that are in need of p rotection over
the next 100 years have be identied and valued. The preferred
options to manage the risks strategically have then been
developed.
Sea level rise and increasing risk
As a consequence of climate change and continued warming of the
global oceans, sea levels are expected to increase in the future.This will increase ood and erosion risk across the Strategy frontageover the next 100 years.
To consider sea level rise, the Strategy has incorporated the latestsea level rise projections (UK Climate Projections 2009) into theood modelling to produce ‘Do Nothing’ ood scenarios for 2025,
2055 and 2115. Following the latest guidelines, under the ‘mediumemissions’ sea level rise scenario, mean sea levels across the strategyfrontage are expected to increase by approximately 0.75m over thecoming century.
The gure (opposite) shows the cumulative relative sea level rise
projections (m) at Cowes over the next 100 years that have beenadopted by the strategy.
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23West Wight Coastal Flood and Erosion Risk Management Strategy
1600
N o .
P r o p e r t i e
s
Years
20202000 20602040 2080 21202100
1400
1200
1000
80 0
60 0
40 0
20 0
0
I n c r e a s e i n m e a n s e a l e v e l ( m )
Increase in sea levels expected (compared to pr esent) as a result of cli mate change
Year
For more detailed information on the extreme waterlevels used in the Strategy please refer to Appendix C:Coastal Processes Review
For more detailed ood mapping see Appendix D:Flood Modelling and Risk Mapping
Coastal ood and erosion risk would increase signicantly in the
future across the Strategy frontage under a ‘Do Nothing’ scenariodue to sea level rise.
As well as residential and commercial properties, there are manyother important features and valuable assets at risk. This includesindustrial sites, public buildings, leisure facilities, a school, ferryterminals, marinas, coastal footpaths, environmentally designated
sites, a cyclepath and beaches.
Increasing number of properties at risk of ooding and erosion over time
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Road between Yarmouth and Shaleet
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a p pr o a c h
Chapter 3
approach
How the
Strategy hasbeen developed Approach to option development
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26 West Wight Coastal Flood and Erosion Risk Management Strategy
Overview of the s tudy area and the Strategy
development process
Before strategic approaches to managing ood and erosion threats
can be identied and evaluated, it is important to understand the
key features, issues and opportunities that exist within the Strategyarea. In order to achieve this, a number of studies and activitieswere undertaken during the early part of the Strategy development.
These included:• Site walkovers and visual inspections – to determine the
location, type and condition of existing coastal defences andassets (See Appendix A for detailed ndings);
• Desktop assessment of potentially con taminated land – toidentify potentially contaminated land uses along the frontagewhich may require defences to prevent them polluting theenvironment (see Appendix B for more details);
• A desktop review of coastal processes – required tounderstand waves, tides, sediment movements and their
interaction around the study area (see Appendix C);• Review and operation of Environment Agency approved
numerical hydraulic models to update previous ood risk
projections and estimate damages from a Do Nothing scenario(see Appendix D for further details).
• Identication of important environmental and heritage
features around the coast – so that key environmentalobjectives and legal requirements to protect the environmentcan be accounted for in the Strategy (see Appendices G, H and Ifor details).
• Engagement with key stakeholders – meaningful engagementwith numerous community groups, organisations and individualsto identify key issues, opportunities and potential for fundingcontributions, and broader outcomes along the shoreline whichcan help to shape future coastal management (see Appendix Efor more details).
A summary of the ndings of these activities required to understand
the baseline for the Strategy is provided in the sections below.
Coastal processes overview – wave, tides, sediment transport
The Strategy frontage is highly diverse and varies in not only incharacter but also with regard to the forcing conditions it experiences,driven by the weather and tides, including prevailing south-westerlywinds. Wave heights vary considerably with large storm waves (5m+)
affecting the exposed open coast environments around FreshwaterBay and the Needles with only small wind driven waves (typically
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27West Wight Coastal Flood and Erosion Risk Management Strategy
EO1
EO1EO2
O1
EO3
EO4
0 1 km
N
O1
O1
EO1
LT11
LT12
LT12
LT13
LT13 LT14
LT8 LT9
LT10
LT10
LT10
LT4
LT4
LT5
LT6
LT7
LT4
FL2
E11
E11
E12
F4
E9E10
E10
FL2
FL2
F4
FL2
E7E8
E9
E9
F4
F2
F3
E5
E6
E6E6
F1
F4
F4
i l l l i i
Totland
Freshwater
YarmouthBouldnor
Cowes
Lymington
Keyhaven
TheNeedles
Alum Bay Headon Hill
TotlandBay
ColwellBay Brambles Chine
Fort Albert
FortVictoria
NortonSpit
B o u l d
n o r
C l i f f Newtown
Harbour
BrickfieldFarm
BurntWood
ThornessBay
Gurnard Bay
Gurnard
EgyptPoint
R i v e
r
M e d
i n a
Hurst Spit
PenningtonMarshes
(s)
WarrenFarm Spit
NeedsOar Point
GullIsland
InchmerryHouse
Stone
Point
Stansore Point
BourneGap
Hillhead
CalshotSpit
Beaulieu
B e a u l i e u R i v e r
LymingtonBanks
(s)
SolentBank(s)
LepeMiddleBank
(s)
BramblesBank
(s)
PrinceConsortShoal (s)
(s)
NewtownGravelBeds
PittsDeep
ParkShore
(s)
(s)
ShinglesBank(s)
Warden Point
Western Yar (s)
Reliability of Information
Low Medium
1 Photographs of key sites andprocesses
Sediment sink(s)
Sediment Types Involved in Transport
Silt and/or Clay
Sand
Sand and Silt/Clay
Shingle
Shingle and Sand
Gravel and Sand
Gravel, Sand and Silt/Clay
Sediment Transport Mechanism
Littoral (beach) drift
Offshore sediment transport
Cliff or coastal slope erosion input
Estuarine sediment transport
Fluvial input
Wave driven nearshore andoffshore zone transport
LT
O
E
EO
FL
F
Volume of Sediment Flow
No quantitative data
Littoral drift divergenceboundary
Littoral drift partial boundary1
5
10
3
4 2
611
8
12
9
7
1314
Sediment transport patterns and pathways around West Wight
Source: SCOPAC Sediment transport study - http://www.scopac.org.uk/sediment-transport.html
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28 West Wight Coastal Flood and Erosion Risk Management Strategy
such as humans, animals, sh, birds and habitats, which could
potentially be affected, were identied.
Next, with use of the erosion predictions, and the ood mapping,
the likelihood of the ‘potentially contaminated land’ areas being atrisk of eroding or ooding was established.
Following this approach, the desktop study identied areas where
there is a high risk of contaminants being released in the future(see Appendix B for full details). The sites identied as high risk inthis review were considered in the appraisal of options; however
it is noted that due to either an inert status or lack of identied
pathways to link sources to receptors these sites have notsignicantly inuenced strategy option choices.
It should be noted that any future coastal defence works near orin potentially contaminated sites should include a more detailedassessment of the contamination risk as part of the Project Appraisal process.
Potentially Contaminated Land
When considering options to manage future ood and erosion risk
it is necessary to consider potential risks to areas of potentiallycontaminated land. Contaminated land is dened as any land
which appears to the Local Authority to be in such a condition, byreason of the substances in, on or under the land, that:
a) Signicant harm is being caused or there is a signicant
possibility of such harm being caused; or b) Pollution of controlledwaters is being, or is likely to be caused.
For land to be formally designated as being ‘contaminated’ it mustbe clearly demonstrated that there is:• a contaminative source present (above a threshold level)• a receptor which can be affected by the source; and• a pathway linking a source to a receptor
Contaminated land often arises from present or historic land
uses such as landlling, industrial processes, military operations,as well as accidents or spills of contaminants, waste disposalor leaking underground storage tanks. In the coastal zone thepresence of contaminated land is a risk because erosion of theshoreline, or ooding, can release the contaminants into the
environment through exposure and leaching. If not dealt withadequately, contaminated material can pose a threat to humanhealth, the environment and sustainable economic development.
In order to determine the risk of contaminated material beingreleased into the environment, the likelihood of contaminated landbeing present along the frontage was rst established. To do thisthe desktop study used former land use data to identify whetherland is likely to be contaminated or not. If an area was thoughtto have potentially contaminating substances, the area wasdesignated as ‘potentially contaminated land’. Then receptors,
For more information see Appendix B:Desktop Contaminated Land Review
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30 West Wight Coastal Flood and Erosion Risk Management Strategy
DRAFT SPA
DRAFT SPA
DRAFT SPA
DRAFT SPA
DRAFT SPA
DRAFT SPA
Solent & Southampton Water SPA/Ramsar
Isle of Wight Downs SAC
Solent Maritime SAC
Solent & Dorest Coast SPA (All Draft)
South Wight Maritime SAC
Important environmental designations around the Strategy frontage
Reproduced from the Ordnance Survey digital data with the permission of the controller HMSO. © Crown copyright and database rights 2016 Ordnance Survey 100019229
1 kilometre
N
SMZ 5
SMZ 1
SMZ 3
SMZ 2
SMZ 6
SMZ 4
SMZ 3
KEY
Project Frontage
Special Areas of Conservation
Ramsar
Special Protection Area
SMZ
Site of Special Scientic Interest
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Environment and heritage designations
West Wight has an abundance of natural features and open spaces.The largely unspoilt, unique and iconic nature of the landscapearound Freshwater Bay, the Needles, the Western Yar Valleyand the Hampstead coast has been recognised throughdesignation as an Area of Outstanding Natural Beauty and alsoas a Heritage Coast.
A number of internationally important sites (see gure left) arefound within the area, including Ramsar sites, Special Protection Areas (SPA) and Special Areas of Conservation (SAC). Areas ofnational importance, such as Sites of Special Scientic Interest
(SSSI) and National Nature Reserves (NNR) can also be found.Many of these important sites are situated along the Strategycoastline and as such it was essential to consider these areaswhen developing the Strategy.
Within many of these important sites there are a number ofdifferent habitats such as marshes, reed-beds, lagoons andintertidal sand and mudats which support a wide diversity of
wildlife. The intertidal mudats are particularly important feeding
habitat for birds, whilst other areas such as the Medina, Yar andNewtown Creek provide an important habitat and nursery area forsh such as bass, ounders and mullet.
Unfortunately, with predicted sea level rise, there will be increasingpressure on many of the important intertidal habitats which get‘squeezed’ against coastal defence structures such as seawalls.This can decrease the size and health of the intertidal habitats
and place additional stresses on the species that rely uponthem. These natural features and associated wildlife also drawand support signicant numbers of visitors for walking, cycling,
ornithology, shing and other recreation.
To help offset these anticipated losses in the future, it is essential forthe Strategy to consider environmental enhancement opportunities.Particular areas signposted for potential environmental mitigationand/or enhancement along the frontage include Thorley Brook
(Yarmouth) and southwest of the Causeway (eastern Freshwater).In addition, allowing natural process to continue where possible isof utmost importance to ensure the coastline and habitats changeand evolve naturally over time.
There is also a range of heritage assets around the West Wightcoastline and ooding and erosion poses a signicant threat to
some of these features of historic importance, and the Strategyhas recognised these in the development of preferredmanagement options.
Stakeholder engagement – understanding what people
want from the coast
Many individuals and organisations have a key interest or stake in
the Strategy shoreline for many different reasons. Each stakeholderis therefore likely to have a unique view on its use, development andfuture protection. Stakeholders or consultees can be an indispensablesource of information which can dene coastal issues and objectives,
steer Strategy development and achieve consensus on the futuremanagement of the shoreline.
A key part of developing the Strategy has involved engaging withkey stakeholders. This has been achieved through publicworkshops, a dedicated key stakeholder bus tour of the frontage,
the establishment of a project Steering Group, and through specicmeetings. This has ensured local communities and working groups,Harbour Authorities, potential developers, local planners, NaturalEngland, the Environment Agency, Heritage England and publicbodies with a vested interest in the West Wight coastline have allbeen consulted and involved.
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32 West Wight Coastal Flood and Erosion Risk Management Strategy
The overall strategic aims of the Strategy engagement processwere;
• to raise an awareness and understanding of coastal ood anderosion risk,
• to identify the challenges and constraints, and• to involve others in the decision making process for managing
the coastline.
Early in the Strategy development phase two dedicated stakeholderworkshops were held in Yarmouth and Cowes to raise awarenessof the Strategy, the problem being addressed and the new systemof partnership funding for future coastal defences. The workshopswere well attended by over 80 people and important stakeholderfeedback was obtained on potential issues and opportunities for theStrategy to consider.
In addition to the stakeholder workshop the Strategy team have
held discussions with a number of individuals and organisationsto discuss the project and to learn more about any concerns andaspirations they might have with regards to the coastline.The Strategy team have learnt a huge amount about how peoplewish to see the shoreline evolve. All of the feedback received todate, where relevant, has been used to inform the development ofthe Strategy to ensure that it takes account of, and captures keystakeholder input and ideas.
The Strategy is now entering a three month period of public
consultation in spring 2016. During this time key stakeholdersand the public are invited to view the proposals and attendpublic exhibitions to review and provide feedback on thedraft Strategy proposals. Please visit www.iwight.com andwww.coastalwight.gov.uk for further details.
Summary of the existing defences
To help establish the baseline ood and erosion risk along the
Strategy frontage it was necessary to identify the standard ofprotection offered by the existing coastal defences, their condition,and how long they are likely to last without maintenance. This wasdone by undertaking a walkover survey of the Strategy shorelineand reviewing the thorough visual assessment of defence conditionundertaken by IWC in line with the Environment Agency’s DefenceCondition Assessment Manual.
Given the number of towns, dwellings and important coastalfeatures, for example in Cowes and Yarmouth, a signicant portion
(around 20km) of the Strategy shoreline is currently defended.There is a wide range of different defence types, from low sea wallsand quays lining the sheltered estuarine and creek areas to largesea walls and esplanades along the more exposed open coast
to protect against erosion and wave overtopping. There are alsostretches of private structures lining waterfronts of residential andcommercial properties, providing individual waterside access anda managed (man-made) shoreline, although often not constructedas defence structures originally. In addition, the open coast isafforded protection by the beaches which act as a barrier to thewaves. There are also long undefended areas with ‘no formaldefences’. In these areas, cliff erosion is often a key risk.
Typically, many of the defences are in a fair condition. There are
also some sections of new defence in very good condition.However, there are also some notable areas where the defencesare in a poor state or provide a low standard of protection againstooding and erosion e.g. Totland, and parts of Yarmouth and Cowes.
For more information see Appendix E:Stakeholder Engagement Feedback
For more information see Appendix A:Defence Condition Review
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Option Development
Overview
Following dening the baseline risks (if we 'do nothing'), and having
gained a detailed understanding of the processes, features andissues operating along the coast, the development and appraisal ofstrategic management options was undertaken.
The 'option appraisal process' refers to the tasks involved inselecting the preferred management options along the Strategyfrontage. The process followed the Environment Agency’s NationalFlood and Coastal Erosion Risk Management guidelines.
Coastal ood and erosion risk management options have been
considered on two interlinked levels; the strategic level options and
the local level measures required to implement these options.
Thinking strategically – management zones
The Strategy frontage was divided into six zones; termed StrategyManagement Zones (SMZs). Each zone (and sub-zone whererequired) is characterised by consistent themes and characteristicssuch as coastal processes, levels of ood and erosion risk,
land uses and Shoreline Management Plan policies. The SMZareas are shown on the map on page 5 and presented in the tableon pages 40 and 41.
For each SMZ, strategic level options were developed andappraised against technical, economic, social and environmental
criteria. The preferred options for consultation were chosen on thebasis of this evaluation.
Option Development Units and identifying
potential local measures
To ensure that the management options proposed by the Strategy arerobust and relevant at the local level it was necessary to split the SMZfrontages into smaller units (termed Option Development Units). Thisprovided the exibility to rene the strategic options to account for
local level variations and requirements.
In total 32 Option Development Units (ODUs) were devised mainlyfollowing the Shoreline Management Plan Policy Units. For clarity,these are numbered 1 to 32 clockwise around the coast (and labelled'W' for the 'West Wight' Strategy. The ODUs are shown on the mapon page 51). Within each of these units the ‘packages of measures’necessary to implement the wider strategic options were established.Each ‘package’ outlined the type of management intervention orworks required over three time periods to implement the strategicoption for the next 100 years.
The locations and key characteristics of each unit are summarised ina table on pages 35 to 39. The boundaries of each unit are shown inthe maps in Chapters 5 to 10.
A workow summary of the option development process, and
subsequent stages, is presented on the opposite page. The followingsections provide a commentary of the key aspects of the process.
For more detail see Appendix J:Option Development and Appraisal
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34 West Wight Coastal Flood and Erosion Risk Management Strategy
Dene
Baseline
Scopingand datacollection
Dene Strategy
ManagementZones (SMZs)
Identify Option
DevelopmentUnits (ODUs)
Develop
baseline foreach SMZand ODU
Develop longlist of potentialoptions
Screening of
long list optionsto develop ashort list ofstrategic options
Detailed appraisalof strategy options(economics, SEA,
HRA, WFD)
Selection andconrmation
of the draftpreferred
options
SteeringGroup, IWCand ProjectBoard approvalof DraftStrategy forconsultation
PublicConsultation3 months;
Spring 2016
Reviewconsultationfeedbackand update /
nalise Strategy
Large ProjectReview GroupReview and
Approval(late 2016)
Key Stakeholderinput▼
Baselinemodelling▼
Key Stakeholderliaison▼
◄ Steering groupinput and review atkey stages
◄ Key Stakeholderliaison
Overview of Strategy development activities
▲ Optioneering sitewalkovers
Identify a package of suitablemeasures in each ODU toimplement strategic options
◄ Explore broader /contributions
outcomes (ongoing)
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Overview table of Option Development Units (ODUs)
ODU Unit Name SMP PU
SMP Policy
toDefence
Residual
Life (years)
Frontage
Maintainer
Indicative ErosionRisk (years from now)
Indicative Flood Risk(years from now)
Coastal
ProcessesLand Use
2025 2055 2115 0-10 10-40 40-100 0-10 10-40 40-100
W1
TennysonDown,
Alum Bay andHeadon Warren
PU6A.2 NAI NAI NAI UndefendedNational Trust+ Private
High waveenergy,exposed cliffline
Open space,attractions (NeedlesPark), farmland,coastal footpath
W2
Southernand CentralTotland Bay
PU6B.1 HTL HTL HTL
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Overview table of Option Development Units (ODUs) continued
ODU Unit Name SMP PU
SMP Policy
toDefence
Residual
Life (years)
Frontage
Maintainer
Indicative ErosionRisk (years from now)
Indicative Flood Risk(years from now)
Coastal
ProcessesLand Use
2025 2055 2115 0-10 10-40 40-100 0-10 10-40 40-100
W9 Norton Spit PU6C.1 HTL HTL HTL 10-20 PrivateLow waveenergy (fetchlimited)
Recreation, harbour
W10
Western YarEstuary -western shore
PU6C.2 NAI NAI NAIMainly
UndefendedPrivate
Estuarine,sheltered
Recreation (boatyard), farmland
W11 The Causeway PU6C.3 HTL HTL HTL 10-20+Environment
AgencyEstuarine,sheltered
Residential,open space
W12 Freshwater Bay PU6A.1 HTL HTL HTL 10-20+ IWC + Private
Bay receivessedimentfrom the west.
Accretion inmiddle, erosion
at anks. Highwave energy
Recreation,residential(apartments)
W13
Western YarEstuary -eastern shore
PU6C.4 NAI NAI NAI Undefended IWCEstuarine,sheltered
Farmland, cyclepath
W14
Thorley Brookand Barnelds
StreamPU6C.5 HTL MR NAI 15-20+
Environment Agency, IWC+ Private
Estuarine,sheltered
Open space (natureconservation)
W15Thorley Brook
to Yar BridgePU6C.6 HTL HTL HTL 15-20+ IWC + Private
Estuarine,
sheltered
Residential,
recreation, school
Erosion & Flood risk: Indicative risk to peopleor assets under a ‘Do Nothing’ Scenario’
Low Moderate HighKEYSMP Policy: HTL = Hold the Line;
NAI = No Active Intervention; MR = Managed Realignment
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Overview table of Option Development Units (ODUs) continued
ODU Unit Name SMP PU
SMP Policy
toDefence
Residual
Life (years)
Frontage
Maintainer
Indicative ErosionRisk (years from now)
Indicative Flood Risk(years from now)
Coastal
ProcessesLand Use
2025 2055 2115 0-10 10-40 40-100 0-10 10-40 40-100
W16
Yar Bridgeto YarmouthCommon
PU6C.6 HTL HTL HTLMainly15-20+
PrivateLow waveenergy (fetchlimited)
Harbour includingferry terminal,behind the harbourare commercialand residentialproperties
W17
YarmouthCommon toPort la Salle
PU6C.6 HTL HTL HTL
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Overview table of Option Development Units (ODUs) continued
ODU Unit Name SMP PU
SMP Policy
toDefence
Residual
Life (years)
Frontage
Maintainer
Indicative ErosionRisk (years from now)
Indicative Flood Risk(years from now)
Coastal
ProcessesLand Use
2025 2055 2115 0-10 10-40 40-100 0-10 10-40 40-100
W23Gurnard toCowes Parade
PU1A.3 HTL HTL HTLMainly15-20+
IWC + Private
Low waveenergy (fetchlimited), weaknet eastwardslittoral drift,landslidereactivationpotential
Residential,recreation (beach
huts), commerical
W24
Cowes TownCentre toFountain Yard
PU1A.4 HTL HTL HTL 15-20+ PrivateLow waveenergy (fetchlimited)
Residential,commerical (largeHigh Street)
W25
Cowes(Fountain Yardto MedinaWharf)
PU1A.4 HTL HTL HTLMainly15-20+
PrivateMostlyestuarine,sheltered
Industrial propertieswith residentialstreets landward,commercialbuildings, harbour,wharfs and a ferryterminal
W26
Central Medina- northwestshore
PU1B.1 NAI NAI NAI Undefended IWC + PrivateEstuarine,sheltered
Farmland, cyclepath
W27West MedinaMills
PU1B.2 HTL HTL HTL 10-20+ PrivateEstuarine,sheltered
Small industrialarea, with privatedefences
W28
Central Medina
- southwestshore PU1B.3 NAI NAI NAI
Mainly
Undefended IWC + Private
Estuarine,
sheltered
Farmland, smallresidential areas,
industrial area tothe south is setbackfrom the frontage
Erosion & Flood risk: Indicative risk to peopleor assets under a ‘Do Nothing’ Scenario’
Low Moderate HighKEYSMP Policy: HTL = Hold the Line;
NAI = No Active Intervention; MR = Managed Realignment
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Overview table of Option Development Units (ODUs) continued
ODU Unit Name SMP PU
SMP Policy
toDefence
Residual
Life (years)
Frontage
Maintainer
Indicative ErosionRisk (years from now)
Indicative Flood Risk(years from now)
Coastal
ProcessesLand Use
2025 2055 2115 0-10 10-40 40-100 0-10 10-40 40-100
W29NewportHarbour
PU1B.4 HTL HTL HTL 10-20+ IWC + PrivateEstuarine,sheltered
Industrialareas, harbour,commercial,residential
W30Central Medina- eastern shore
PU1B.5 NAI NAI NAIMainly
UndefendedIWC + Private
Estuarine,sheltered
Farmland, wastewater pumpingstation, recreation(harbour andholiday park),disused industrialfacility
W31
East Cowes(Kingston RoadPower Stationto ShrapeBreakwater)
PU1A.5 HTL HTL HTLMainly15-20+
PrivateLow waveenergy (fetchlimited)
Industrial facilities(including fueldepot and powerstation), residential,commericialbuildings andwharfs, harbour,ferry terminal
W32
East Cowesouter Esplanade(ShrapeBreakwaterto Old CastlePoint)
PU1A.6 HTL NAI NAI 15-20+ IWCLow waveenergy (fetchlimited)
Recreation areawith residentialpropertieslandward, woodland
Erosion & Flood risk: Indicative risk to peopleor assets under a ‘Do Nothing’ Scenario’
Low Moderate HighKEYSMP Policy: HTL = Hold the Line;
NAI = No Active Intervention; MR = Managed Realignment
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Summary of the Management Zones
Zone 1 2 3a 3b 3c 4
Name Needles
Headland
Totland and
Colwell Bays
Yarmouth Coast Western Yar Estuary Freshwater Newtown Coast
Geographic
Extent
Fort Redoubt tosouthern limit of
Totland Bay
Southern limit ofTotland Bay to Fort
Victoria
Yarmouth town andFort Victoria to Port la
Salle
Western Yar Estuaryshoreline including
Thorley Brook andBarnelds Stream
Freshwater Bay,Freshwater Village
and the Causeway
Bouldnor cliff toThorness Bay,
including NewtownEstuary
Option
Development
Units
W1 W2 to W7 W8 to W9 andW15 to W17
W10, W13 and W14 W11 and W12 W18 to W20
SMP Policy
(2011)
No Active Intervention Mixed (Hold theLine in the south.Transferring from Holdthe Line to No ActiveIntervention in thenorth)
Mixed (Hold the Linearound Yarmouthand to the east.Transferring from Holdthe Line to No ActiveIntervention in the
west)
No Active Intervention,with ManagedRealignment atThorley Brook
Hold the Line No Active Intervention
Zones
Characterised
by (Common
themes /
issues)
• Undefended, cliffedcoastline
• Exposed to largewaves
• Small number ofassets at risk fromerosion at theclifftop
• No ood risk• Leisure /
recreational use
• Cliffs subject tolandsliding
• Residential andcommercialproperties at risk oferosion
• Popularrecreational area
• No ood risk
• Yarmouth is a keyresidential areaand town centre
• Signicant oodand erosion risks
• Roads thatprovide accessto other parts ofthe Island at riskfrom ooding and
erosion• Ferry terminal
provides link tomainland
• Recreation areaand farmland
• Cyclepath situatedon the eastern sideof the estuary
• Predominantlyundefended
• Small and localisedood and erosionrisks
• Mostly shelteredand estuarine
• Residential andcommercialproperties at riskfrom ooding
• Low lying area atood risk betweenCauseway andFreshwater Bay
• Freshwater Bayexposed to largeswell waves thatcan result inovertopping of thedefences
• Erosion risk atFreshwater Bay
• A3055 at risk ofooding
• Open space• Undefended• Environmentally
important area• Small localised risk
of erosion• No ood risk
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41West Wight Coastal Flood and Erosion Risk Management Strategy
Summary of the Management Zones (continued)
Zone 5a 5b 6a 6b 6c
Name Gurnard Luck
and Gurnard cliff
Gurnard to
Cowes Parade
Cowes and
East Cowes
Medina Estuary (and East
Cowes Outer Esplanade)
Newport Harbour
Geographic
Extent
Gurnard Luck / Gurnardmarsh area
Cowes headland, fromGurnard Bay to Cowes
Parade
Cowes: Cowes Parade toMedina Wharf.
East Cowes: Shrapebreakwater to KingstonRoad power station
Medina Wharf andKingston Road Power
Station south to NewportHarbour and ShrapeBreakwater to Old CastlePoint
Newport Harbourand quayside
Option
Development
Units
W21 to W22 W23 W24 to W25 and W31 W26 to W28, W30, W32 W29
SMP Policy
(2011)
Mixed (Hold the Linechanging to No ActiveIntervention at GurnardLuck. No Active
Intervention to the east)
Hold the Line Hold the Line Mixed (mainly No ActiveIntervention, plus Holdthe Line at West MedinaMills and Hold the Line
transferring to No ActiveIntervention at East Cowesouter esplanade)
Hold the Line
Zones
Characterised
by (Common
themes /
issues)
• Signicant riskof ooding atGurnard Luck
• Erosion risk because ofthe close proximatelyof properties to thecoastline
• Existing private defenceshave relatively low crestlevels
• The developed coastalslopes have potential forlandslide reactivation
• Erosion is more of asignicant risk than
ooding
• There are existingsea wall defences,overtopped at low pointsat high tide events
• Cowes and East Cowesare key urban centres
• Signicant residentialand commercialproperties at risk fromboth ooding and
erosion• Waterfront access is
important• Two ferry terminals
provide links to themainland
• Land is predominantlyfarmland andrecreational land
• Small landslides haveblocked access nearOld Castle Point
• Few properties at riskfrom ooding anderosion
• Waterfront access isimportant
• Commercial andindustrial propertiesclose to the waterfrontand at risk of ooding
• If the harbour wallsfailed a number ofproperties are at risk ofdamage
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Seawall
Steel Sheet Piling
Beach Nourishment/Recycling
Earth Embankment
Armorl oc Revetement
Groynes
Temporary Flood Barriers
Property Level Protection
Land raising
Setback Floodwall
Timber Clad Sheet Pile Wall
Rock Revetment
Potential measures to implement the strategic management options
Image courtesy by Fluvial Innovations
D l i th St t i O ti
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Developing the Strategic Options
In order to be able to assess the relative merits of different Strategyoptions, the baseline ood and erosion risks associated with a
‘Do Nothing’ approach were derived in each SMZ for the presentday, 2025, 2055 and 2115. This allowed the risk areas within eachSMZ to be identied, and the timing of risks to be dened. This
understanding formed a basis from which to develop a numberof potential ‘strategic options’ for the management of ood and
erosion risk. The scope, or long list, of strategic options consideredacross the SMZs included:
• Do Nothing – no active intervention (baseline scenariodeveloped in each SMZ).
• Do Minimum – e.g. maintain health and safety obligations,minor reactive maintenance / repairs.
• Maintain – continue to protect against erosion. However, thestandard of protection (SoP) against ooding would be expected to
fall over time as sea levels rise.
• Adaptation / resilience / relocation – through the implementationof a coastal change management area plan.
• Sustain – maintain a minimum SoP by raising defences over timeto keep pace with sea level rise.
• Improve SoP – improve the SoP compared to the present day.• Environmental mitigation / Improvement – including managed
realignment and habitat creation.
Variations of the above options were also considered.
From the long list of strategic options, a short list of potentiallysuitable methods for achieving them were selected and dened for
appraisal in each SMZ (typically four or ve of the most appropriate
methods were identied for each SMZ). A table summarising the
potential strategic options assessed for each SMZ is presented inthe following table,
Strategic options considered for each Strategy Management Zone (SMZ):
SMZ 1 (W1) Potential Strategic OptionsNeedles Headland
Do nothing – No active intervention. Baseline scenario.
SMZ 2 (W2 – W7) Potential Strategic OptionsTotland and Colwell Bays
Do nothing – No active intervention. Baseline scenario.
Do minimum – Maintain H&S and access as long as possible and develop coastalchange management area plan (W2-W6).
Maintain then Improve from 2025 – Phased seawall improvement and cliffstabilisation. Maintain defences (W2-W4) until end of design life then implement phasedcliff drainage and sea wall stabilisation works (for example a mass rock revetment).Do minimum elsewhere.
Improve (now) – Seawall stabilisation works (for example a mass rock revetment)and cliff stabilisation and drainage now (W2-W4). Do minimum elsewhere.
SMZ 3a (W8-9, W15-17) Potenti al Strategi c OptionsYarmouth coast (Fort Victoria to Port la Salle)
Do nothing – No active intervention. Baseline scenario.
Do minimum – H&S and access. Flood warning and emergency response plan.
Maintain (and Temporary Flood Barriers) then Improve from 2055 – Use TemporaryFlood Barriers to manage and reduce ooding to areas at signicant risk by sustaining a1 in 75 year (1.33 % AEP) standard of protection. Prevent erosion to critical infrastructureserving the town and the West Wight. From 2055, if funding can be secured, raise /implement new defences (bunds and oodwalls) to manage long term increase in oodand erosion risk posed by sea level rise.
Maintain (and PLP) then Improve from 2055 – Use Property Level Protection tomanage and reduce ooding to residential properties at very signicant risk. Preventerosion to critical infrastructure serving the town and the West Wight. From 2055,if funding can be secured, raise / implement new defences (bunds and oodwalls) to
manage long term increase in ood and erosion risk posed by sea level rise.Improve (now) – Raise / implement new defences (bunds and oodwalls) now tomanage longer term increase in ood and erosion risk posed by sea level rise.
SMZs 3,4, 5 and 6 overleaf ►
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Strategic options considered for each Strategy Management Zone (SMZ)
(continued):
SMZ 3b (W10, W13-14) Potential Strategic Opt ionsWestern Yar Estuary
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – H&S and access (minor repairs to cyclepath i.e. debris removal).
Do Minimum with Managed Realignment between 2025 and 2055 – Maintainexisting structures, H&S and cycle and footpath access. If funding can be secured,
managed realignment at Thorley Brook between 2025 and 2055 to provideenvironmental mitigation and create intertidal habitat.
Maintain – Maintenance of existing structures (including cycle path repairs) andrefurbishment at end of design life.
SMZ 3c (W11-12) Potenti al Strategic OptionsFreshwater (The Causeway and Freshwater Bay)
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – H&S and access. Flood warning and emergency response plan.
Adaption and Resil ience (and PLP) / Do Minimum – Recommend Property LevelProtection and ood warning / emergency response plan for residential properties at
very signicant risk.
Maintain (and PLP) then Improve (2055) – Maintenance of existing structures andrecommend Property Level Protection to the residential properties at signicant oodrisk. Refurbishment of existing defences at Freshwater Bay at end of design life toprevent erosion risk and implement new defences at Freshwater Village in the longterm to mitigate ood risk and improve the standard of protection.
Maintain and Improve (now) – Maintain existing defences at Freshwater Bay, improvestandard of protection at Freshwater Village. Refurbishment and Improve existingdefences at end of design life at Freshwater Bay to mitigate erosion risk and implementnew defences at Freshwater Village to improve the standard of ood protection.
SMZ 4 (W18-20) Potential Strategic Options
Newtown CoastDo nothing – No active intervention. Baseline scenario.
SMZ 5a (W21-22) Potenti al Strategic OptionsGurnard Luck and Gurnard cliff
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – H&S and access. Provide ood warning and emergencyresponse plan.
Do Minimum and Resilience then Adapt – Recommend community and propertylevel ood resistance at Gurnard Luck. Private maintenance of existing assetspermitted (subject to usual consents). In the long term ood risk will increase due to
sea level rise but provide a coastal change management area plan to support the SMP(2010) No Active Intervention Policy. Do minimum (maintain H&S) at Gurnard cliff.
Maintain – Maintenance of existing structures at Gurnard Luck and refurbishment atend of design life. Flood risk will increase over time due to sea level rise. Develop oodwarning and emergency response plan. Do minimum (maintain H&S) at Gurnard cliff.
SMZ 5b (W23) Potential Strategic OptionsGurnard to Cowes Parade
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – Maintain H&S and access and also provide coastal changemanagement area plan.
Maintain – Maintenance of existing structures and refurbishment or replacement at theend of their residual life to reduce risks of erosion and landslide reactivation. Flood riskwill increase due to sea level rise.
Improve (now) – Implement seawall stabilisation works along Cowes – Gurnard toreduce erosion risk and increase standard of ood protection.
SMZ 6a (W24-25, W31) Potenti al Strategic OptionsCowes and East Cowes
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – H&S and access. Provide ood warning and emergencyresponse plan.
Do Minimum (and PLP) then Adapt – Recommend Property Level Protection forresidential properties at very signicant risk and maintain H&S and access. Adapt andprovide ood warning / emergency response plan.
Maintain – Maintenance of existing structures and refurbishment at end of design life. Accept standard of protection will fall over time.
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Strategic options considered for each Strategy Management Zone (SMZ)
(continued):
Sustain (with Temporary Flood Barri ers and PLP) then Improve from 2055 –In the short and medium term maintain the existing defences and use TemporaryFlood Barriers and Property Level Protection to sustain a 1 in 75 year (1.33% AEP)standard of protection in the areas at signicant ood risk. Use redevelopmentopportunities to facilitate the raising / implementation of new strategic defences.In the long term (from 2055), if the funding can be secured, implement new defencessuch as seawalls or setback oodwalls to manage the increase in ood and erosionrisk posed by sea level rise.
Sustain (with PLP) then Improve fr om 2055 – In the short and medium termmaintain the existing defences and use Property Level Protection and a ood warning/ emergency response plan (no Temporary Flood Barriers) to manage and reduceooding to residential properties at signicant risk. Use redevelopment opportunitiesto facilitate the raising / implementation of new strategic defences. In the long term(from 2055), if the funding can be secured, implement new defences such as seawallsor setback oodwalls to manage the increase in ood and erosion risk posed by sealevel rise.
Improve (now) – Replace and raise frontline defences to provide a 1 in 200 year (0.5% AEP) standard of protection.
SMZ 6b (W26-28, W30, W32) Potential Strategic Options
Medina Estuary (and East Cowes Outer Esplanade)Do Nothing – No active intervention. Baseline scenario.
Do Minimum – H&S and access.
Maintain – Maintenance of existing structures and refurbishment at end of design life. Accept standard of protection against ooding will fall over time due to sea level rise.
SMZ 6c (W29) Potential Strategic OptionsNewport Harbour
Do Nothing – No active intervention. Baseline scenario.
Do Minimum – Maintain H&S and access. Provide ood warning and emergencyresponse plan.
Maintain (and PLP) then Improve from 2055 (through redevelopment) – In theshort term recommend Property Level Protection to manage and reduce oodingto the few residential properties at very signicant risk. Maintain then refurbishexisting defences once they reach the end of their service life. In the long term useredevelopment opportunities to facilitate the raising / implementation of new strategicdefences to improve the standard of ood protection.
Maintain (and PLP) then Improve from 2055 (through a fro ntline scheme) – In theshort term recommend Property Level Protection to manage and reduce ooding tothe few residential properties at very signicant risk. Maintain then refurbish existingdefences once they reach the end of their service life. A new frontline scheme from2055 to improve the standard of ood protection.
Improve (now) – Raise / implement new frontline defences to manage longer termincrease in ood risk posed by sea level rise.
Strategic Option Appraisal
The next stage in the Strategy development process was to appraisethe strategic options to select the preferred option for each SMZ.This appraisal process included an economic appraisal (Benet :
Cost analysis), a number of environmental assessments, social andtechnical appraisals and a consideration of funding and affordability.This process was undertaken to ensure that the preferred options putforward are economically viable and deliverable, meet the Strategyobjectives and are technically robust, socially acceptable andenvironmentally sustainable.
Technical aspects
A primary consideration in the development of a Strategy is to knowis to know which proposals are technically viable. There is little pointin undertaking detailed economic and environmental appraisals, orrecommending an option, if the option in question cannot reasonablybe implemented on the ground.
Technical considerations include considerations include the defencetype in question, timing of works, space and height requirements,
all in the context of the specic location and present condition of thesite in question.
For example, for a currently undefended, open space location, thereare few technical issues and a wide range of options are likely to betechnically viable (e.g. revetments, seawalls, land raising, oodwalls,
earth bunds etc ) However for a more constrained site such as • Maintaining waterfront connectivity links to the sea and improving
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earth bunds etc.). However, for a more constrained site, such asa dense urban environment where space may be very limited,signicant technical challenges may be present for many options
(e.g. land raising or earth bunds which require space) and may limitthe technically feasible options to those such as a oodwall which
require a smaller footprint to implement.
In order to be able to assess the technical feasibility of options a
sound appreciation of the coastline was therefore required.This was achieved through the baseline assessments undertaken.In addition, numerous site walkovers were carried out to assessthe practical and technical constraints offered along the coastline inrespect to the various local measures identied. This understanding
of the Strategy area, coupled with the project team’s extensiveengineering judgement, allowed the technical feasibility of optionsto be appraised.
Social aspects
Stakeholder engagement with key organisations was undertakenduring the development of the options. This included a bus tourof the frontage with key stakeholders and as well as dedicatedstakeholder workshops. There continues to be ongoing liaison withmany of the organisations along the frontage. The feedback andinformation received during Strategy development provided a clearunderstanding of stakeholder needs, desires and opportunitiesto deliver wider outcomes. A number of recurring and commonthemes and aspirations were raised by stakeholders for theStrategy to consider. These include (not in order of importance):
• Robust ood and erosion risk management – protecting keyassets and people
• Maintain critical infrastructure and the ferry links to the Island• Maintaining and improving coastal access (i.e. walking, cycling,
shing, nature watching and leisure pursuits)
• Maintaining waterfront connectivity, links to the sea and improvingharbour facilities
• Safeguarding cultural and natural heritage assets• Protecting, enhancing and creating environmentally important sites• Maintaining recreational space areas• Keeping natural areas unspoilt• Maintaining the Islands tourism economy• Linking new defences with redevelopment opportunities
The option appraisal process accounted for these aspirations and theintent of the preferred options is to support and facilitate these wherepossible.
Environmental aspects
With so many environmentally and culturally important areas anddesignations on the Island, key environmental considerations andobjectives helped shape the preferred strategic options. This wasachieved through a Strategic Environmental Assessment (SEA) which
was undertaken as an integral part of the option appraisal process(see Appendix G). The SEA appraised the potential impacts of eachshort listed strategic option against the following categories:
• Biodiversity• Climate• Cultural heritage• Human health• Landscape• Material assets
• Soil• Water
The interrelationship between each of the above categories wasalso considered.
The environmental appraisal information was included as part The costs of a strategic option were estimated based on the defence
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The environmental appraisal information was included as partof the evidence for selecting the preferred option. Where possibleit is intended that the preferred options should not signic