West Rhyl Coastal Defence - IEMA · 2018-07-20 · West Rhyl Coastal Defence Scheme – Environmental Statement Final Cascade Consulting 4 The West Rhyl Coastal Defence Scheme aims

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

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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


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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)


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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



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.



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



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



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



• 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



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



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



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



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.

Figure 2





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)



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



• 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.



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.

FIGURE 4


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




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.



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




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



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.

Figure 7




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



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.

Figure 8




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)



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.

Figure 9




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

[email protected] or alternatively by post to:

Denbighshire County Council Development Control

Caledfryn

Smithfield Road

Denbigh

Denbighshire

LL16 3RJ



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.

Documents

West Rhyl Coastal Defence - IEMA · 2018-07-20 · West Rhyl Coastal Defence Scheme – Environmental Statement Final Cascade Consulting 4 The West Rhyl Coastal Defence Scheme aims