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West Rhyl Coastal Defence Scheme
Environmental Statement Non‐Technical Summary
11 October 2010
CH028/ES/NTS
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting
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Client: Denbighshire County Council Title: West Rhyl Coastal Defence Scheme – Environmental
Statement: Non-Technical Summary Project No: CC312 Date of Issue: 11 October 2010 Status: Final Version No: 1.0 Produced By Authorised for Release By ……………………………….. …………………………………… Alex Hampson Liz Baker Environmental Scientist Technical Director CONTACT DETAILS CASCADE CONSULTING Enterprise House Manchester Science Park Lloyd St North Manchester M15 6SE Tel: 0161 227 9777 Fax: 0161 227 1777
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting
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Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting
Non-Technical Summary
[Volume 1 – Main Text, is provided as a separate document] [Volume 2 – Technical Appendices, is provided as a separate document] Contents 1.1 Introduction ............................................................................................................ 1 1.2 Scope of Assessment and Consultation ................................................................. 5 1.3 Approach to Environmental Impact Assessment .................................................. 8 1.4 Planning Policy Context ......................................................................................... 8 1.5 The Proposed Scheme ............................................................................................ 9 1.6 Environmental Impacts ........................................................................................ 17 1.7 Cumulative Effects Assessment ........................................................................... 35 1.8 Summary ............................................................................................................... 39 1.9 Contacts and Further Information...................................................................... 40
LIST OF FIGURES Figure 1 Existing Site Figure 2 General Arrangement of Proposed Scheme and Surrounding Areas Figure 3 Land Ownership and Proposed Extent of Site Works Figure 4 Typically High Baseline Current Speeds within Foryd Harbour on a Spring
Tide at HW -1h20m and HW +1h40m Figure 5 Environment Agency Flood Map (Existing) at and Around the Proposed
Works and Existing Flood Defence Measures Figure 6 Predicted Extreme Flood Map with Scheme (2115 in 200 Year Tidal Flood) Figure 7 Noise Monitoring Locations Figure 8 Visual Impact Assessment from Key Views Figure 9 Cumulative Effects Assessment Scheme Locations in Relation to the Coastal
Defence Works LIST OF TABLES Table 1 Environmental Issues Scoped In/Out LIST OF PLATES Plate 1 General View within Outer Harbour Plate 2 Damage at the Foot of the Training Wall Plate 3 Damage to the Training Wall Plate 4 Existing Revetment with Buried Toe Plate 5 Artistic Impression of Proposed Outer Harbour (not to scale) Plate 6 Artistic Impression of Proposed Inner Harbour (not to scale) Plate 7 Artistic Impression of Proposed Phase 1 & 2 Intersection with Phase 3 shown
in Background (not to scale)
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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NON TECHNICAL SUMMARY
1.1 INTRODUCTION
1.1.1 The Application
Denbighshire County Council is seeking planning permission to undertake coastal
defence works on the seafront in Rhyl, North Wales. Substantial areas of the town
are below high tide level, so when waves overtop the existing seawall or the defences
are breached, there is a major risk of flooding. The existing coastal defences are in
need of upgrading to improve protection of the town against flooding, and
Denbighshire County Council therefore proposes to provide a new harbour wall,
training wall and revetment to meet this requirement. The existing site, where the
works would be located, is shown in Figure 1.
Figure 1 Existing Site1
1.1.2 About This Document
The purpose of this Non-Technical Summary is to present an overview, in non-
technical language, of the main findings of the Environmental Impact Assessment
reported in the Environmental Statement. It includes a description of the proposed
1 Google Earth, Data SIO, NOAA, US Navy, NGA, GEBCO © 2010 Europa Technologies, Image © 2010 Bluesky, Infoterra Ltd & COWI A/S, © 2010 Tele Atlas
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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scheme, how the construction and operation is expected to affect people and the
environment and proposes ways to eliminate, mitigate or reduce any significant
adverse effects on the environment. It also includes a description of any residual
impacts that are expected to remain after mitigation.
The Environmental Statement has been prepared in accordance with the Town and
Country Planning (Environmental Impact Assessment) (England and Wales)
Regulations 1999 (as amended) and will be presented in support of the planning
application to Denbighshire County Council and Conwy County Borough Council.
The application will be subsequently reviewed and determined by Denbighshire
County Council Development Control in consultation with Conwy County Borough
Council. Any significant residual impacts identified in the Environmental Statement
will be taken into consideration by the councils when they decide whether to grant
planning consent for the proposed works.
Other consents are also being sought from Welsh Assembly Government Marine
Consents Unit and the Environment Agency Wales for aspects of the works but they
do not form part of the Environmental Statement.
1.1.3 The Need for the Rhyl Coastal Defence Works
Previous studies have indicated the spatial extent of flooding from the sea in the
absence of the defences along the coastline. There are particularly high risks to the
western part of Rhyl and along the line of the A548 between West Rhyl and
Prestatyn. There is, therefore, substantial risk to assets in these areas, including
residential and commercial properties.
The existing coastal defences along the Rhyl coastline comprise a sea wall and
training wall. However, if these defences are breached, or waves overtop the
structures, there is the potential for significant flooding to occur. The sea wall across
the whole of the Rhyl frontage is susceptible to severe overtopping and studies have
shown that the length between Foryd Harbour and Drift Park to the east requires
upgrading in order to improve protection of Rhyl against flooding. In addition, there
is an urgent need to upgrade the training wall which trains the River Clwyd out to sea
away from Rhyl Promenade frontage.
Plates 1 to 4 show the general study area, including examples of the existing
condition of the coastal defences.
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Plate 1 General View within
Outer Harbour
Plate 2 Damage at the Foot of the
Training Wall
Plate 3 Damage to the Training
Wall
Plate 4 Existing Revetment with
Buried Toe
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The West Rhyl Coastal Defence Scheme aims to provide relief from both erosion and
overtopping of the existing sea defences in order to provide greater protection to
properties inland of the promenade wall at Foryd Harbour and east of the Ocean
Plaza site. The scheme design has been undertaken using both the Department for
Environment Food and Rural Affairs/Welsh Assembly Government guidance2 which
accounts for an extreme storm event (one estimated to occur on average once in 200
years) and allowing for 100 years of sea level rise3. The proposed scheme lies within
the regeneration area of Foryd Harbour where developments are being planned,
potentially including a new hotel and supermarket on the Ocean Plaza site. The
scheme also fits well within the strategy for the Rhyl frontage, where improvements
have already been undertaken at Drift Park.
1.1.4 Alternatives Options
The Environmental Impact Assessment Regulations require the main alternatives to
the proposed scheme that have been studied, and the principal reasons for their
rejection, to be outlined in the Environmental Statement.
Alternative locations were not considered because the proposed scheme involves the
improvement of existing infrastructure. However, a number of alternative options
and designs were evaluated to address the objective of the scheme, which is to reduce
flood risk at Rhyl taking into account climate change impacts of predicted sea level
rise and the consequent increased risk of wave overtopping at Rhyl frontage. These
alternative options have been described and discussed in the Environmental
Statement and are summarised below.
Do Nothing (Option 1) - no works, including maintenance would be undertaken,
which would result in an ever-increasing risk of both flooding to Rhyl and
deterioration of the coastal defences.
Do Minimum (Option 2) - this is the approach currently being taken by
Denbighshire County Council in attempting to maintain the existing defences against
flood and erosion events. However, this option does not address the risk of
overtopping along various sections of the harbour wall.
Improve (Options 3–7) – a previous report originally considered five
improvement options with a view to achieving up to an average 100 year life of the
coastal defences. All of the options included upgrading of the training wall, works to
2 Flood and Coastal Defence Project Appraisal Guidance (FCDPAG3) – Economic Appraisal 3 The overall coastal defence scheme has been designed for a 1 in 200 year return period, with an allowance for 100 years increase in sea level, with the exception of the training wall. The training wall has been designed in line with current sea-level rise, although provision has been made within the design to allow for future improvements based on future sea level rise prediction to 2115
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the sea wall to the east of the training wall up to Drift Park, and various proposals for
improvement to the harbour wall from Foryd Harbour to the intersection with the
training wall.
Improve (Option 8) - another improvement option was later suggested by the Rhyl
Foryd Harbour Forum comprising the provision of rock tipping out from the harbour
wall and current inshore groyne on Horton’s Nose.
1.1.5 Option Selection and Preferred Option
The advantages and disadvantages of each option were reviewed, taking into account
the ability of the works to fulfil the objectives of the West Rhyl Coastal Defence
Scheme; construction and operational costs; engineering practicability; and potential
environmental impacts on transport, access, recreation, landscape and visual
amenity during construction.
On balance, Option 5 was identified as the preferred solution for providing the
required level of flood protection while minimising the impacts of the works. In
comparison to the other options, it had a moderate capital cost and low maintenance
cost.
1.2 SCOPE OF ASSESSMENT AND CONSULTATION
1.2.1 Consultation
The scope of the Environmental Impact Assessment was established through
consultation with statutory bodies and interested parties, which is a key element of
assessing the environmental impacts of a scheme. Consultation allows a full
understanding of the baseline environment and potential nature of impacts.
The consultation programme included the preparation and submission of a Scoping
Report and Scoping Opinion request to Denbighshire County Council in December
2009 together with a number of meetings with stakeholder groups to discuss the
proposals. The Scoping Report was copied to the following consultees:
• Cadw • Centre for Environment Fisheries and Agriculture Science • Clwyd and Conwy Rivers Trust • Clwyd-Powys Archaeological Trust • Conwy County Borough Council • Countryside Council for Wales • Crown Estates • Denbighshire County Council • Dwr Cymru Welsh Water • Environment Agency Wales
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• Maritime and Coastguard Agency • Marine and Fisheries Agency • North Wales Wildlife Trust • Rhyl and St Aphans Angling Association • Rhyl Charter Skippers Association • Rhyl Environmental Association • Rhyl Fisherman’s Association • Rhyl Foryd Harbour Forum • Rhyl Town Council • Rhyl Water Ski Club • Rhyl Yacht Club • RNLI (Rhyl Station) • Welsh Assembly Government Marine Consents Unit • Welsh Yachting Association.
1.2.2 Scope of Assessment
As a result of the scoping and consultation process, key issues for the Environmental
Impact Assessment were identified as shown in Table 1. This table identifies
construction and operational phase issues that have been scoped into the
Environmental Impact Assessment and those which have been scoped out.
Table 1 Environmental Issues Scoped In/Out
Topic Key Environmental Issues During Construction During Operation Hydrodynamics Impact of sheet piling and rock armour
placement works Potential for increased flow velocities, altered flow directions and changes to water level caused by scheme modifying channel
Sediment Transport
Mobilisation of sediments caused by works Potential for increased size of training wall to interrupt east west long-shore sediment drift
Flood Risk Potential for increased temporary risk during works to existing flood defences
Benefit by reducing coastal flood risk
Water and Sediment Quality
Potential for increased turbidity, reduction in dissolved oxygen and release of contaminants
Potential impact to dilution/dispersion of point and diffuse sources of faecal pollution
Flora and Fauna Potential to affect designated sites from impacts on water quality, noise and disturbance
Potential impact of disturbance to terrestrial ecology, birds and otters
Potential impact of sediment re-suspension and mobilisation of contaminants to aquatic ecology
Potential impact of piling upon aquatic ecology
Potential delays or disruption to fish migration
Potential for adverse effects on aquatic ecology as a result of accidental pollution
Potential for modification to sediment transport systems to impact upon local protected sites
Potential for modification of the channel to cause erosion of Horton’s Nose
Potential for modification of the flow regime to impact upon migratory fish species
Potential impact on bivalve populations from modification of sediment transport within the Clwyd Estuary
Air Quality Potential for dust to impact air quality Scoped out as completed
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Topic Key Environmental Issues During Construction During Operation
Potential for construction plant and HGV emissions to impact air quality
infrastructure will not affect air quality
Noise and Vibration
Potential for noise and vibration from construction works and traffic to cause nuisance to local noise sensitive receptors
Potential for noise impact from construction compound
Scoped out as completed infrastructure will not generate noise or vibration
Transport Increased pressure on local road network due to HGV movements required to deliver materials and plant
Increased pressure on local road network due to construction workforce traffic
Disruption to cycle routes
Scoped out as completed infrastructure will not generate traffic or affect transport routes
Navigation Impact of in channel construction works on marine users
Impacts of the change in profile of the training wall on marine users
Impacts of the change in profile and alignment of the harbour wall on marine users
Changes to flow conditions within the channel and the sediment transport regime
Landscape and Visual Amenity
Increase in traffic due to HGV deliveries affecting views from properties
Large construction plant such as cranes impacting upon sea views during construction of training wall and stepped revetment
Piling works and rock armour placement affecting in harbour visual amenity
Storage of materials on the foreshore affecting sea views
Erection of construction compound and site office affecting landscape
Lighting required for night time working
Potential for the scheme to affect the character of the townscape, seascape and landscape
Heritage Potential impact on local submerged archaeology and the City of Ottawa wreck
Potential impact on local archaeology and the built environment in general
Potential impacts on the setting or remains of built heritage or archaeological features
Human Impact of the demolition of the existing landing platform for chartered angling industry
Scoped out as landing platform will be replaced after construction
Impacts on the wider social or economic environment have been scoped out
Waste Management
Scoped out as waste issues during construction will be resolved through Site Waste Management Plan to be produced post-application
Scoped out as once built, the proposed scheme will not generate additional waste
Sustainability Scoped out as locally sourced materials will be used where possible in construction
Scoped out
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1.3 APPROACH TO ENVIRONMENTAL IMPACT ASSESSMENT
1.3.1 General Assessment Approach
Scoping and consultation with Denbighshire County Council, Conwy County Borough
Council and a number of other consultees comprising statutory organisations and key
stakeholders identified the key issues to be covered by the Environmental Impact
Assessment.
The existing environment at the site of the proposed scheme has been fully assessed
as part of the Environmental Impact Assessment. Baseline analysis included both
desk-studies and baseline surveys.
The likely significant environmental effects have been predicted for each relevant
topic (e.g. flora and fauna, water and sediment quality, heritage) through the
comparison of baseline conditions (i.e. without development) with conditions that
would result through the construction and operation of the proposed scheme.
Potentially sensitive receptors, including local residents and businesses; the Clwyd
Estuary; areas with special conservation status; and the wider community were also
identified during the scoping process. Significant effects have been reported in the
Environmental Statement.
Mitigation measures to avoid, reduce or remedy any adverse impacts have been
identified and incorporated into the scheme design and construction methods where
appropriate.
The significance of residual environmental impacts, i.e. those impacts that remain
following the implementation of any mitigation measures, has been determined by
reference to impact criteria for each assessment topic. These criteria classify impacts
according to whether they are major, moderate, minor or negligible in
magnitude, and whether they are considered to be adverse, neutral or beneficial
in terms of their effect.
Impacts identified as major or moderate adverse or beneficial are regarded as
significant in terms of planning considerations.
1.4 PLANNING POLICY CONTEXT
1.4.1 National Guidance
Planning Policy Wales and Technical Advice Notes set out the Welsh Assembly
Government’s national policies on different aspects of land use planning. The most
recent issue which has been taken into consideration during the Environmental
Impact Assessment of the proposed coastal defence scheme is Planning Policy Wales
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Edition 3 July 20104. The extent to which the proposed scheme complies with these
policies, and those discussed below, can be found in a separate Planning Statement
that has been submitted with the planning application.
1.4.2 Regional Guidance
Shoreline Management Plans set out objectives for the management of coastlines.
The Rhyl coastline falls under the Liverpool Bay Shoreline Management Plan sub-cell
11a Management Unit 45. The objective set out for the Rhyl coastline is “hold the
line” or maintain the current position in terms of defending the coastal area from
flooding. This requires improvements to the coastal defences at Rhyl, as proposed by
this scheme.
1.4.3 Local Guidance
The Denbighshire Unitary Development Plan 1996 – 20116, Colwyn Borough Local
Plan7 and Clwyd Structure Plan: Second Alteration8 provide the most relevant local
planning policy guidance and the proposed coastal defence scheme broadly complies
with the policies in these plans.
1.5 THE PROPOSED SCHEME
1.5.1 Scheme Description
The proposed scheme will include the following three main elements:
Phase 1 – Upgrading of the River Clwyd training wall, which trains the river flows
out to sea away from the Rhyl Promenade frontage. The existing training wall would
be encased with a rock armour profiled structure. On the western side of the training
wall, five navigation markers will be installed to aide navigation and at the training
wall/harbour wall intersection, two new linked static access platforms will be
incorporated to replace the existing informal landing platform, currently used by
harbour users.
Phase 2 – Improvement to the existing sea wall, from Foryd Harbour Bridge to the
intersection with the training wall, subdivided by the proposed Foryd Harbour
Sustainable Transport Bridge9 as the inner and outer harbour. This will comprise the
installation of sheet piles and placement of rock armour at varying slopes to address
overtopping. The existing concrete sea wall will be removed and replaced with a
wave return wall. At the request of the Rhyl Foryd Harbour Forum, a pontoon is 4 Planning Policy Wales Edition 3 (July 2010) 5 Shoreline Management Plan – SMP 1 (Liverpool Bay Shoreline Management Partnership, 1999) 6 Denbighshire Unitary Development Plan 1996 - 2011 7 Colwyn Borough Local Plan, Adopted 31 March 1999 8 Clwyd Structure Plan: Second Alteration (Conwy version), Adopted 31 March 1999 9 The Foryd Harbour Sustainable Transport Bridge Scheme will be subject to a separate planning application
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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proposed to be installed immediately upstream of the inner/outer harbour wall
intersection.
Phase 3 – Precast stepped concrete revetment and wave wall to the east of the
training wall at the intersection with the existing seawall between Sydenham Avenue
and John Street. This will create a promenade facility with soft landscaping and car
parking facilities behind the flood wall, although this element of the scheme will be
subject to further detailed design and agreement with Denbighshire County Council.
In addition to the main three elements of the scheme outlined above, a series of
additional works are proposed including:
• improvements to the footpath and cycle path behind the sea wall
• themed decorations on the landward face of the wave return wall
• highways drainage improvements
• provision of hand rails along the promenade, where necessary
• temporary removal and re-installation of the promenade lighting along the
harbour wall following completion of the works
• temporary relocation of the bus stop located between Sydenham Avenue and
Quay Street during Phase 1 and 2 of the works and provision of new facility at a
suitable location to be agreed with the Local Highways Authority.
A layout plan of the proposed coastal defence works is shown in Figure 2. Artistic
impressions of the proposed scheme are set out in Plates 5 to 7.
The extent of land required for the proposed permanent works plus any temporary
working areas is illustrated by the red line boundary in Figure 3. This shows that
the permanent works fall within Denbighshire County Council’s land ownership, with
the exception of the northern end of the training wall which falls within land owned
by the Crown Estates and a small section of the training wall which lies within Conwy
County Borough Council’s land ownership. The temporary construction compound
will be located within a site owned by Scarborough Development Group.
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Plate 5 Artistic Impression of Proposed Outer Harbour (not to scale)
Plate 6 Artistic Impression of Proposed Inner Harbour (not to scale)
Plate 7 Artistic Impression of Proposed Phase 1 & 2 Intersection with
Phase 3 shown in Background (not to scale)
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1.5.2 Construction
The overall contract duration is likely to be 30 months, which includes some
preliminary demolition works and construction of all three phases. Although split
into phases, the construction of the training wall and harbour wall (Phases 1 and 2) is
expected to be undertaken on several sections at the same time, as the work has to be
undertaken when most of the estuary is dry, at low tide. This will maximise the
working window within the tidal sequence, i.e. during the lowest tides (springs), a
team will construct the training wall extremity working landwards, whilst another
team will progress the works from the landward end during the neap tides, when
water levels at low tide are slightly higher. Due to the need to work during low tide,
some night-time working will be required.
The duration of Phases 1 and 2, including site establishment, is likely to be 18 months
from January 2011 to July 2012. Casting of the concrete stepped revetment units will
be undertaken at a suitable location off site, while the Phase 1 and 2 works are
ongoing. Phase 3 will then commence on site following completion of Phases 1 and 2
in July 2012, with an estimated completion date of mid 2013.
The construction of each structure would be largely shore-based; no work will be
undertaken from boats or barges. Tracked excavators will work on the foreshore at
low tide to facilitate construction at the toe of the training wall. When access to the
foreshore is required during the construction programme, public access to sections of
the promenade would be restricted. Best practice guidelines for working in coastal
waters would be adhered to with no fuelling or vehicle maintenance to be carried out
on the foreshore or in the Clwyd Estuary channel.
It has been agreed in principle with Scarborough Development Group, who own the
former fairground site at Ocean Plaza, that an area of land within their ownership
will be made available for a contractor’s compound/laydown area for materials and
plant. This area provides a direct route off the main B5118 West Parade and directly
onto the foreshore east of Sydenham Avenue. The compound may also be used to site
a concrete batching plant if this is used by the contractor in preference to importing
readymix concrete.
Details of the construction methods and programme are provided in the
Environmental Statement, including the following:
• demolition and construction plan and programme
• description of works
• materials and resource use
• hours of work
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• traffic generation and routing.
1.5.3 Environmental Management Plan
A Framework Environmental Management Plan has been prepared which presents
an overview of the mitigation and environmental protection measures set out within
the Environmental Statement. The mitigation measures are required to minimise
environmental impacts within the development site and the surrounding area during
the demolition and construction phase of the proposed development. The
Framework Environmental Management Plan provides an outline of how
construction activities will be managed, including designation of responsibilities for
implementing the mitigation measures, monitoring their effectiveness, and taking
remedial action in the event that an unacceptable impact is identified. It provides a
basis for the detailed Environmental Management Plan which is normally provided
post-consent as a requirement of planning conditions.
The Environmental Management Plan will be a live document which will be updated
as required throughout the course of the development programme. Prior to
commencement of demolition and construction activities, the Environmental
Management Plan will be reviewed and updated by Denbigshire County Council’s
appointed principle contractor subject to discussions with development control
officers from Denbighshire County Council and Conwy County Borough Council, as
required.
1.6 ENVIRONMENTAL IMPACTS
1.6.1 Overview
This section provides a summary of the significant residual impacts on receptors that
are likely to arise from the proposed scheme.
Hydrodynamic and Sediment Regimes The hydrodynamic regime near to the proposed scheme was investigated to assess
what effects the scheme would have on flow speeds, flow directions and water levels
within the estuary and the wider coastal environment. The Clwyd Estuary typically
has high flow speeds during the incoming flood and retreating ebb tide in the area
around the inner and outer harbour wall, as shown in Figure 4. The local sediment
regime, including processes such as deposition, erosion and movement of sand along
the coast, was also investigated. These investigations are critical since the
hydrodynamic and sediment regimes affect other key receptors such as ecology and
navigation.
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Temporary Impacts
Following mitigation, the hydrodynamic and sediment regimes investigations found
that there were no significant impacts during construction as a result of the proposed
scheme. Minor adverse residual impacts during construction would be limited to
sediment release from disruption of the channel bed or beach as a result of activities
such as excavation, piling and vehicle movements.
Long-term Impacts
The hydrodynamic and sediment regime investigations found that there were no
significant operational impacts as a result of the proposed scheme. Residual impacts
during operation include a minor adverse impact on the sediment regime, 100m
east of the training wall and fronting the stepped revetment; a temporary minor
neutral impact to sediment regime in the channel fronting West Parade; a potential,
limited increase in the erosion of Horton’s Nose (seen as partly beneficial as the
accretion of this feature has been a hindrance to harbour users), a minor neutral
increase in flows at Horton’s Nose and in the channel fronting West Parade and a
minor adverse reduction in wind blown sand reaching the area approximately
250m east of the training wall.
Flood Risk/Flood Consequence Assessment West Rhyl is in a low lying area that is at risk from flooding from both the sea and the
adjacent estuary. Up to 2,500 existing residential/commercial properties are
considered to be at risk of flooding from an extreme 1 in 200 year tidal flooding event
(i.e. that would occur on average once in 200 years) overtopping the existing coastal
defences. The extent of existing flood risk in the area around the works is illustrated
in Figure 5. This shows that with existing defences during the extreme 1 in 200 year
tidal flood, flooding to a depth of up to 3m could occur in Rhyl, which would be
potentially catastrophic. The proposed coastal defence scheme has been designed so
that the risk to people and properties from tidal flooding is substantially reduced.
Temporary Impacts
Negligible residual flood risk impacts are predicted during the construction phase
of the proposed coastal defence scheme.
Environment Agency flood map (existing)at and around the proposed works andexisting flood defence measures
Flooding from rivers or seawithout defences (EA data)
Extent of extreme flooding (EA data)
Existing flood defences
Area benefiting from flooddefences (EA data)
Main River (EA data)
Approximate footprint of scheme
Figure 5
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Long-term Impacts
The proposed scheme would lead to a significant reduction in overtopping of the
coastal defences, which would lead to a significant reduction in flood risk, in terms of
extent and depths of flooding. Flooding that could occur with the proposed defences
in 2115, were the 1 in 200 year extreme tidal flood to occur, is illustrated in Figure 6.
The area and extent of flooding is substantially less than that which would occur with
existing defences. Flooding depths would be no greater than 0.6m (compared to 3m
with the existing scheme) and the number of properties affected by the flooding
would also be reduced. As such, the scheme is considered to have a permanent
major beneficial operational impact with regard to flood risk.
Water and Sediment Quality
Temporary Impacts
Following the implementation of mitigation measures, including adoption of good
working practices, no significant residual water and sediment quality impacts are
predicted during the construction phase of the proposed coastal defence scheme.
Long-term Impacts
No significant residual water and sediment quality impacts are predicted during the
operational phase of the proposed coastal defence scheme. Minor beneficial
residual impacts from enhanced dilution of Clwyd Estuary waters as a result of the
training wall improvements may slightly improve the quality of the local bathing
waters.
Flora and Fauna
Temporary Impacts
Construction activities may result in temporary disturbance to birds using the Clwyd
Estuary and surrounding habitats, although when not directly threatened birds are
known to habituate to disturbance. The impacts on bird populations have been
assessed as minor adverse and temporary.
Use of good construction practice will minimise sediment resuspension and noise
related disturbance of resident and migratory fish populations. In-channel works will
be undertaken during low tide. Where in-channel works cannot reasonably be
avoided during peak migratory periods, appropriate breaks in piling activities will
provide sufficient time for migratory fish to pass the areas of works. Residual impacts
are considered to be minor adverse and temporary.
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Other impacts on ecological receptors, including European designated sites10, from
construction activities are considered negligible.
Long-term Impacts
The proposed scheme will result in limited land take, with the majority of works
replacing or improving existing man-made features and therefore the potential
impact magnitude of the scheme is considered to be low. Where habitat will be lost
to the scheme due to construction of the stepped revetment, the land is considered to
be of low ecological value.
Localised hydrodynamic changes as a result of the scheme may cause low level of
disturbance to non-statutory designated sites, namely the Clwyd Estuary and
Floodplain, and Horton’s Nose Wildlife Sites. These impacts are considered to be
minor adverse.
There are no significant residual ecological impacts predicted to result from
operation of the scheme.
Air Quality Temporary Impacts
The proposed works will include a number of specific dust-generating activities as
part of the demolition and construction activity. In the absence of mitigation,
temporary and localised dust impacts could affect sensitive receptors, including
residential properties, up to 500m from the site. Where appropriate, dust generating
activities will be undertaken off-site, however, where this is not possible these
activities will be located away from the site boundary and sensitive receptors. Good
construction practice will be adopted to further reduce dust emissions.
With implementation of these mitigation measures, the impacts on air quality will be
reduced. The receptors that may still be affected include the residential properties on
Sydenham Avenue, which lie within 25m of the contactor’s compound. These
residual impacts are considered to be temporary and of minor adverse
significance.
The predicted impacts due to vehicle emissions from road vehicles associated with
the scheme are not considered significant.
10 A separate report to support a Habitats Regulations Assessment has been prepared and submitted to the Countryside Council for Wales
Predicted extreme flood map with scheme(2115 1 in 200 year tidal flood)
Predicted floodpath
Extreme flood map(with proposed scheme)
Stepped
Revet
men
t
Figure 6
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting 27
Long Term Impacts
No local air quality or dust impacts are anticipated during the operational phase of
the proposed coastal defence scheme.
Noise and Vibration Temporary Impacts
Noise sensitive receptors include residential properties and hotels along Ford Road
(adjacent to Sunnyvale Holiday Campsite), West Parade, Sydenham Avenue and
surrounding roads, and Sunnyvale Holiday Campsite (Figure 7). Construction noise
impacts were assessed as worst case scenarios and took into consideration the
combined impact of various construction activities taking place concurrently.
Mitigation measures, including use of best practice guidance; restricting piling
activities to daytime only; use of hydraulic or vibration rather than percussive piling
techniques; working in areas away from sensitive receptors during night-time
working; and the erection of hoardings around the construction compound will
reduce noise and vibration impacts. The impact on the individual receptors will not
be for the full duration of the construction period, as the works would be carried out
in different parts of the site at different times. The residual noise impacts have been
assessed as temporary minor/moderate adverse. There will be no significant
residual vibration impacts from proposed piling activity.
Long Term Impacts
No noise or vibration impacts are anticipated during the operational phase of the
proposed coastal defence scheme.
Transport Temporary Impacts
Transport of construction materials to the site will necessitate a large number of
vehicle movements to and from the site. Deliveries of materials will be carefully
managed to minimise disruption to the local road network. A number of measures
will be implemented, including:
• restricting access to the site by HGVs to 09.00 – 15.30 with approximately 39
HGV deliveries per day within this restricted window
• using a dedicated access route for major deliveries, including the rock armour
and sheet piles on 20 tonne vehicles. The preferred route, which has been agreed
with Denbighshire County Council, brings traffic from the A55 across the Foryd
Harbour Bridge via the A525, A547 and A548, thereby limiting the number of
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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roads in the local network likely to be affected by the construction works
• a contractor’s compound located between Quay Street and Sydenham Avenue
will be designated for the storage of material
• rock will be offloaded by road delivery vehicles in the contractor’s compound and
transferred to suitable 4x4 or 6x6 wheel drive dump trucks for delivery to the
foreshore.
The implementation of the proposed mitigation measures will reduce the impact of
the HGV traffic to a temporary moderate adverse significance.
The impact of traffic generated by the construction workforce is considered to be of
temporary minor adverse significance.
The section of the B5118 West Parade between the roundabout adjacent to the Foryd
Harbour Bridge and Quay Street will require temporary road closure limited to short
periods during plant delivery and when piling is being undertaken from the
promenade. Once appropriate diversions have been put in place, the impact has been
assessed as being of temporary moderate adverse significance.
Restricted pedestrian access to the promenade will be for short periods during
construction of all phases. As such, the impact is considered to be of minor
adverse significance.
Long Term Impacts
No transport impacts will arise during the operational phase of the proposed coastal
defence scheme.
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Landscape and Visual Amenity
Temporary Impacts Construction activities will result in short term landscape impacts on Rhyl
Promenade and the intertidal zone and beach. The phased approach to the
construction may assist in limiting impact to certain areas during certain phases,
however, the potential landscape impacts cannot be completely avoided. Therefore,
the residual impact on landscape during construction will be of moderate adverse
significance.
The construction phase will result in temporary, significant adverse impacts on visual
receptors in the immediate vicinity of the construction works and traffic routes
(identified as key view numbers 2, 3, 4, 5, 6, 7, 9, 10, 11 and 12 on Figure 8).
Hoardings around the construction site and the phasing of works will minimise
impacts to some receptors, however, mitigation measures will have a limited effect on
the level of impacts identified due to the scale of the proposals and the duration of the
construction period, albeit phased. Therefore, the residual impacts on visual amenity
will be of major/moderate adverse significance.
Long Term Impacts
Following construction, the overall scheme is considered to have moderate
beneficial impact on landscape features owing to the terrestrial and seaward
enhancements to Rhyl seafront. No significant residual visual impacts have been
identified at the operational stage.
Heritage
Temporary Impacts
The potential impacts of the scheme on archaeological sites and built heritage include
physical impacts, and visual impacts upon the setting, of heritage assets during
construction. The excavation operations associated with the coastal defences will not
impact upon any known archaeological deposits and are therefore of negligible
significance. By implementing mitigation measures to minimise the effects of
vibration from piling, residual impacts on the City of Ottawa will also be negligible.
However, any potential physical impacts to undiscovered palaeoenvironmental
remains are unknown. An appropriately qualified archaeologist will monitor the
removal of material from the areas where excavation is taking place to record any
palaeoenvironmental deposits or archaeological remains should they be identified.
The impacts upon the setting of the the wreck of the City of Ottawa and the listed
Foryd Harbour Bridge will be temporary and are considered to be of minor adverse
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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significance.
Long Term Impacts
The potential impacts of the operational phase of the scheme on archaeological sites
and built heritage include visual impacts upon the setting of features. There will be
impacts of minor adverse significance on the setting of the City of Ottawa wreck
and Foryd Harbour Bridge as a result of the scheme.
Navigation
Temporary Impacts
During construction, vessel navigation may be affected by construction works within
the estuary, changes in flow, and a potential increased risk of collision. Mitigation
measures which will be implemented to reduce or avoid any impacts include:
• working in the channel only to be carried out at low tide when the channel is not
navigable
• provision of temporary navigation markers during the works to guide mariners
away from the working area
• the working methods of placing rather than dropping rock armour will reduce the
likelihood of material being misplaced, and any material on the channel bed
outside the works footprint will be removed before the next tide to avoid hazards
to vessels
• any lighting required will be specified and positioned appropriately to avoid
imitating navigation aids and to reduce visual impact during night time working
• regular liaison with the harbour and river users will be carried out so that they
are fully aware of the upcoming activities to ensure that they can make suitable
alternative arrangements.
After the implementation of mitigation, the potential risk of collision or obstruction
during construction of the training wall and harbour wall has been assessed as a
temporary minor adverse residual impact. The impact of losing the informal
landing platform on the training wall has been assessed as a temporary moderate
adverse impact. The existing floating pontoon on the west quay of the harbour will
remain accessible to all harbour users, however, this facility is accessible for a shorter
time than the informal landing platform due to tidal restrictions.
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Long Term Impacts
Following implementation of mitigation measures, including provision of a “Notice to
Mariners” or similar at the end of the works, to provide an overview of all the changes
made, no significant adverse impacts to navigation are anticipated. The proposed
scheme, once in operation, will improve safety for vessel users through the increased
visibility of the training wall. In addition, the provision of the new static landing
jetties on the training wall and additional pontoon on the inner harbour wall will
greatly improve access to the Foryd Harbour in the long term and is considered to be
of minor beneficial significance.
Human
Temporary Impacts
The scheme has been designed to compensate for the loss of the informal landing
platform on the training wall (which is used by charter vessels to board paying
passengers over a wider tidal range and thus increases their potential trip duration
and revenue) by including two new linked static landing jetties on the harbour wall.
However, these will not be accessible until after construction is complete. During
construction, vessels can use the existing floating pontoon on the western harbour
wall, although this has a slightly restricted tidal range compared to the training wall.
The residual impact is, therefore, considered to be of temporary moderate adverse
significance.
Long Term Impacts
No long term impacts to chartered angling vessels’ activities are anticipated during
the operational phase of the proposed coastal defence scheme.
1.7 CUMULATIVE EFFECTS ASSESSMENT
In accordance with Schedule 4 of the Environmental Impact Assessment
Regulations11, the Environmental Statement includes consideration of cumulative
effects. These are impacts that result from incremental changes caused by other past,
present or reasonably foreseeable actions together with the proposed scheme. The
combined effects of several development schemes may, on an individual basis, be
insignificant but cumulatively may have a significant effect.
The Environmental Statement has thus considered the impacts of the proposed
scheme in combination with the potential environmental effects of other identified
proposed developments taking place in the vicinity of the coastal defence works. The
schemes which may run concurrently with the proposed coastal defence scheme
11 Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 1999 (as amended)
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting 36
include:
• Reconfiguration of Moorings within Foryd Harbour
• Removal of the City of Ottawa wreck.
• Foryd Harbour Sustainable Transport Bridge
The locations of these schemes in relation to the coastal defence works is shown in
Figure 9.
The cumulative effects assessment concluded that in general, residual cumulative
effects will be similar to those residual impacts arising from the coastal defence
scheme alone, resulting in no net change. However, some potential cumulative
effects have been identified, arising mainly during the construction phase of the West
Rhyl Coastal Defence Scheme when other schemes are being progressed within the
harbour at the same time. These include adverse impacts of noise, changes to water
levels and flows, and increased sediment disturbance and turbidity in the estuary.
Combinations of these impacts could affect local residents, harbour users and the
ecological value of the study area. The majority of cumulative impacts for the
construction phase are associated with construction of the Foryd Harbour
Sustainable Transport Bridge.
Depending on when construction contracts are let for each of the proposed schemes
and hence when the resulting construction programmes are known, it will be
necessary to review the need for coordinated mitigation measures and to update the
Environmental Management Plan for the coastal defence works accordingly. As all
agreed cumulative schemes are being promoted by Denbighshire County Council,
effective co-ordination of construction programmes should be possible to mitigate
cumulative impacts arising from the various construction activities.
After construction, when the schemes are operational, the most significant
cumulative impacts arise from the reduced navigable access to the channel as a result
of the new inner harbour pontoon associated with the coastal defence scheme and the
moorings reconfiguration scheme; and potential increased vessel collision risk due to
the position of the proposed cycle bridge caisson and cantilever landing.
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
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1.8 SUMMARY
Throughout the construction programme, temporary adverse impacts are anticipated
especially in relation to traffic movements, construction noise, landscape and visual
amenity, and impacts associated with the loss of amenity and navigational access in
the harbour area. A Framework Environmental Management Plan has been prepared
to ensure that the mitigation measures and monitoring described in the
Environmental Statement are implemented and are effective in reducing impacts on
sensitive receptors.
Ongoing consultation with Denbighshire County Council and other consultees
throughout the design process has benefited the overall design of the proposed
scheme and minimised impacts on sensitive receptors wherever possible.
The improvements brought by the West Rhyl Coastal Defence scheme will result in
long term major beneficial impacts through reduced risk of flooding and hence a
reduced risk to life, disruption to those living and working in Rhyl and the potential
for damage to property. No significant long term adverse impacts have been
identified. There will also be a long term beneficial impact on landscape and visual
amenity, and improved navigational access and landing facilities within Foryd
Harbour, which will be of benefit to the harbour users.
The proposed scheme will have a positive impact on Rhyl and the beneficial impacts
of the scheme are considered to outweigh the potential for negative impacts.
1.9 CONTACTS AND FURTHER INFORMATION
This Environmental Statement is available for viewing by the public during normal
office/opening hours at the Planning Departments of Denbighshire County Council
and Conwy County Borough Council.
The Environmental Statement is also available for viewing at Rhyl Library, Church
Street, Rhyl, LL18 3AA.
Comments on the planning application can be sent via email to
planning@denbighshire.gov.uk or alternatively by post to:
Denbighshire County Council Development Control
Caledfryn
Smithfield Road
Denbigh
Denbighshire
LL16 3RJ
Denbighshire County Council West Rhyl Coastal Defence Scheme – Environmental Statement Final
Cascade Consulting 40
Comments on the planning application can also be sent to Conwy County Borough
Council by post to:
Planning Office,
Conwy County Borough Council
Civic Offices,
Colwyn Bay,
LL29 8AR
Additional electronic copies (CD or DVD) of the full Environmental Statement can be
purchased from Denbighshire County Council, priced at £15 and a hard copy of the
Environmental Statement can be purchased for £85. Free copies of the Non
Technical Summary can be obtained by writing to Denbighshire County Council
Development Control at the address above.
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