clanmoyle flood alleviation scheme environmental report

109 Pages·2012·5.33 MB·English

by  Serena Keane

Dublin City Council

Comhairle Cathrach Bhaile Atha Cliath

CLANMOYLE FLOOD ALLEVIATION

SCHEME

ENVIRONMENTAL REPORT

Revision B - July 2012

Clanmoyle Flood Alleviation Scheme Environmental Report

CONTENTS

1. INTRODUCTION 2
1.1 This Document 2
1.2 Wad Flood Relief Scheme – Project Overview 2
1.3 Planning and Regulatory Context 3
1.4 Project Context 7
2. RECEIVING ENVIRONMENT, IMPACTS AND MITIGATION 10
2.1 Introduction 10
2.2 Human Beings 10
2.3 Water Quality 15
2.4 Ecology 19
2.5 Geology and Hydrogeology 25
2.6 Noise and Vibration 28
2.7 Air Quality and Climate 31
2.8 Cultural Heritage 32
2.9 Landscape and Visual Assessment 33
3. ENVIRONMENTAL CONSIDERATIONS FOR MIDDLE WAD FLOOD
ALLEVIATION SCHEME 39
4. CONCLUSION 41

Appendix A – Appropriate Assessment Stage 1 Screening Report
Appendix B – Drawings
Appendix C – Geophysical Survey

Nicholas O’Dwyer Ltd. i July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

1. INTRODUCTION
1.1 This Document
This Environmental Report has been prepared by Nicholas O’ Dwyer Ltd. on behalf
of Dublin City Council (DCC). It supports the Part 8 Planning Application for the
Clanmoyle Flood Alleviation Scheme, the first phase of the WAD Flood Alleviation
Scheme. This Environmental Report constitutes an environmental assessment of
the potential impacts of the proposed Clanmoyle Flood Alleviation scheme on the
environment in general. Section 2 of this document addresses the main EIS
themes, assesses any potential environmental effect of the scheme and proposes
mitigation measures as appropriate. A brief appraisal of environmental
considerations for Phase 2 the Middle WAD Flood Alleviation scheme is presented
in Section 3 for completeness although Part 8 planning is not being progressed for
this scheme at this time.
1.2 Wad Flood Relief Scheme – Project Overview
The Wad River drains a catchment area of approximately 483 hectares, including
parts of Ballymun, Santry, Donnycarney, and Killister to the seafront at Clontarf
in North County Dublin. The Wad River, originally an open channel, has been
completely replaced with culverts and pipelines of varying dimensions over the
6km route from Albert College Park Road to the seafront at Clontarf.

There have been a number of historical flooding events reported within the Wad
catchment area. Recent flooding events occurred in August 2008 and July 2009
as a result of extreme rainfall in the catchment. These events caused significant
damage to property and as a result the Wad Catchment Study was initiated to
recommend a scheme which would reduce the risk of flooding within the
catchment. A further flood event in October 2011 compounded the need to
progress suitable flood alleviation measures.

The aim of the Wad Catchment Study was “to carry out a full catchment study of
the River Wad from the source to the outlet at Clontarf”. The study was required
to recommend a scheme which would reduce the risk of flooding within the
catchment.

Nicholas O’Dwyer Ltd. 2 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

The recommended flood alleviation scheme comprises three area based sub-
schemes as follows

 Sub Scheme 1: Clanmoyle Flood Alleviation Scheme
 Sub Scheme 2: Middle Wad Flood Alleviation Scheme
 Sub Scheme 3: Upper Wad Flood Alleviation Scheme.

This Environmental Report supports Part 8 Planning Application for Sub Scheme
1, the Clanmoyle Flood Alleviation Scheme which is being progressed at this time.
1.3 Planning and Regulatory Context
1.3.1 Environmental Impact Assessment (EIA)
The primary legislation governing EIA in Ireland is the Local Government
(Planning and Development) Regulations 2001 and the European Communities
(Environmental Impact Assessment) Regulations 1989 to 2006. Projects
requiring EIA are listed under Annex I and II of the 2001 Regulations. Though
Flood Relief Works are listed under Annex II, Section 10;

“Canalisation and flood relief works, where the immediate contributing sub-
catchment of the proposed works (i.e. the difference between the contributing
catchments at the upper and lower extent of the works) would exceed 1,000
hectares or where more than 20 hectares of wetland would be affected or where
the length of river channel on which works are proposed would be greater than 2
kilometres”

This project does not qualify under these criteria as the entire catchment area of
the WAD River is only 483 hectares, no wetland is affected and there is no
existing river channel on which works are proposed.

The Planning and Development (Strategic Infrastructure) Act 2006, provides for
the making to An Bord Pleanala of applications for planning permission in respect
of certain proposed developments of strategic importance, and for certain other
amendments to the Planning and Development Acts 2000-2004. Though
canalisation and flood relief works are listed under Schedule 7 of this Act, the
criteria for making an application to the Bord are identical to the criteria in the
Nicholas O’Dwyer Ltd. 3 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

Local Government (Planning and Development) Regulations 2001 (listed above)
and therefore an application to the Bord is not necessary.
1.3.2 Sub Threshold EIA
Article 120(1) of the Regulations 2001 states that “where a local authority
proposes to carry out a sub-threshold development, and where it considers that
the development would be likely to have significant effects on the environment, it
shall prepare, or cause to be prepared, an EIS in respect thereof.
Guidance as to how the local authority determines if the project is likely to have a
significant effect on the environment is contained in Environmental Impact
Assessment (EIA) Guidance for Consent Authorities regarding Sub-threshold
Development (DEHLG, August 2003). There is a requirement for account to be
taken of the;
 Characteristics of the proposed development;
 Location of the proposed development; and
 Characteristics of potential impacts

As of the 13 June 2011, the Planning Department of Dublin City Council considers
the Clanmoyle Flood Relief Scheme ‘sub threshold’ for the purposes of EIA and
considers that the impacts are unlikely to be sufficient to warrant preparation of a
full EIS.

Notwithstanding the above and following consultation with the Planning
Department it has been determined that in the interest of observing best practice
it would be prudent to prepare an Environmental Report1 addressing the main EIS
themes to assess any potential environmental effects of the scheme.
1.3.3 Appropriate Assessment
Irrespective of the need for an EIA, due to the Natura 2000 site designations
within the Tolka Estuary and Dublin Bay, Dublin City Council must take into
account Regulation 29 of the Natural Habitats Regulations S.I. No. 94/1997 which
outlines the obligations of the competent authority to undertake an Appropriate
Assessment where a development is likely to have potentially significant effects,

1 Ref. Guidelines on the information to be contained in Environmental Impact Statements EPA (2002) - sections
2.4.4 & 2.4.7
Nicholas O’Dwyer Ltd. 4 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

either individually or in combination with other developments on a Natura 2000
site i.e. a Special Area of Conservation (SAC) or a Special Protected Area (SPA).

In accordance with the Habitats Directive S.I. No. 94/1997 any plan or project
that has the potential for a significant effect on an SAC or SPA must be screened
in order to determine whether an Appropriate Assessment is required. The
recommended Wad Flood Alleviation Scheme drains directly to the Sandymount
Strand/Tolka Estuary SPA (Site Code 004024) and is within 5km of a number of
other Natura 2000 sites including the South Dublin Bay SAC (Site Code 000210),
the North Dublin Bay SAC (Site Code 000206), and the North Bull island SPA (Site
Code 004006). Therefore the scheme must be screened to determine if an
Appropriate Assessment is required.

A Stage 1 Screening Report was prepared in December 2011 by Nicholas O’
Dwyer Ltd. on behalf of Dublin City Council to assess the potential impacts of Sub
Scheme 1, the Clanmoyle Flood Alleviation Scheme and Sub Scheme 2, the Middle
Wad Flood Alleviation Scheme on Natura 2000 sites. This document is included in
Appendix A. It concluded that there would not be significant impacts from Sub
Scheme 1 and 2 on Natura 2000 sites.
1.3.4 Dublin City Development Plan 2011-2017
Development in the Wad catchment area is governed by Dublin City Council
(DCC).

TheDublin City Development Plan states that ‘The active pursuit of flood risk
management strategies and sustainable urban drainage systems also enables the
city to adapt to climate change.’

The implementation of the Wad Catchment Study recommendations is an
essential element for providing adequate drainage infrastructure to the area. The
sustainable development of the area cannot progress without the necessary
infrastructure and services. Therefore the recommended scheme not only
complies with the requirements of the area development plan but is fundamental
to its success.
Nicholas O’Dwyer Ltd. 5 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

1.3.5 Part 8
The Wad Flood Alleviation Scheme is subject to an accompanying application for
consent under Part 8 of the Planning and Development Regulations 2001 (S.I.
600 of 2001). Part 8 Planning Permission is currently being sought for the various
elements of the Sub Scheme 1, the Clanmoyle Flood Alleviation Scheme. This
Environmental Report supports the Part 8 Planning Application for this scheme.
The design and scope of works for Sub Scheme 2, the Middle Wad Flood
Alleviation Scheme and Sub Scheme 3, the Upper Wad Flood Alleviation Scheme
have yet to be finalised.

Part XAB
Part XAB is a new provision of the Planning & Development Acts, 2000-2010,
which places a greater emphasis on the impacts a plan or project may have on
sites or species of a particular ecological value (Part XAB refers to new provisions
within Part X of the amended legislation). Every land-use plan prepared by Local
Authorities, on its own or in combination with other plans or projects, must be
screened to determine if any significant effects are likely to arise on the integrity
of the Natura 2000 Network (Appropriate Assessment Screening Report).
Following the screening procedure, it may be determined that a Natura Impact
Report (NIR) is required to be prepared. The NIS would need to be compiled for
submission to An Bord Pleanala and the procedure as per Section 177AE of Part
XAB, inserted after Part X by Section 57 of the Planning and Development Act.

As the Stage 1 Screening Report for Appropriate Assessment for the proposed
scheme completed in December 2011 determined that there would be no
significant impact on Natura 2000 sites from the proposed works, the normal Part
8 procedure is followed, save that the screening report completed by the Planning
Department shall be placed on display with the Part 8 documentation in
Accordance with Article 83 and 249 (6) of the Planning and Development
(Amendment) Act 2010.
1.3.6 Foreshore License
A Foreshore License is required for the outfall at Clontarf. The Foreshore Acts
(1933-2005) require that a lease or license must be obtained from the Minister for
the Environment, Heritage and Local Government for the carrying out of works or
placing structures or material on, or for the occupation of or removal of material
from the foreshore. Dublin City Council submitted a foreshore license application
Nicholas O’Dwyer Ltd. 6 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

for the Clontarf outfall to the Department on the 27th May 2010. As of the 18th of
June 2012 a Foreshore License has yet to be granted by the department.
1.4 Project Context
1.4.1 The Need for Flood Alleviation Measures
Flooding events occurred in August 2008, July 2009 and October 2011 as a result
of extreme rainfall in the catchment. These events caused disruption to road and
rail traffic, significant damage to property and posed a significant risk to public
safety. The Wad Flood Alleviation Scheme is required in the interest of public
safety and to reduce the risk of future damage and disruption from flooding
within the Wad catchment.
1.4.2 Description of WAD Flood Alleviation Scheme

A description of the key components of the Wad Flood Alleviation Scheme is
outlined below. The locations of individual components of the scheme are
presented in Figure 1.1 overleaf.

Sub Scheme 1: Clanmoyle Flood Alleviation Scheme
 Construction of a flood routing culvert from Clanmoyle (A) to Clontarf Golf
Club (B)
 Attenuation storage in Clontarf Golf Club (C)

Sub Scheme 2: Middle WAD Flood Alleviation Scheme
 New Culvert from Collins Park to Clontarf Golf Club (D)
 New culvert across the Howth Road (E)
 A new outfall culvert to the sea in Clontarf (F). This outfall will be located less
than 20 metres to the West of the existing outfall.

Sub Scheme 3: Upper WAD Flood Alleviation Scheme
 Localised works will be required to the west of the M1 in order to alleviate the
risk of flooding

Nicholas O’Dwyer Ltd. 7 July 2012
Clanmoyle Flood Alleviation Scheme Environmental Report

Clanmoyle Flood
Alleviation
Scheme

Figure 1.1 Location of key components of the proposed Middle Wad and Clanmoyle
Flood Alleviation Schemes

1.4.3 Description of Clanmoyle Flood Alleviation Scheme
A detailed description of the key components of Clanmoyle Flood Alleviation
Scheme is outlined below. The locations of individual components of the schemes
are presented in the appended drawings.

This proposal forms the first phase of a wider proposal to address the flooding
issues experienced in the Wad catchment. The overall scheme will provide an
additional tunneled culvert from Collins Park to the Clontarf Golf Club, the
tunneled upgrade of the culvert capacity at Howth Road and an additional outfall
to the bay. The layout of the scheme is detailed on drawing numbers 20446-PP-
01 to 07.

The Clanmoyle Flood Alleviation scheme for which this permission applies affords
protection to the houses in Clanmoyle who have experienced flooding as a result
of extreme rainfall events in recent years. The proposal provides for an inlet
Nicholas O’Dwyer Ltd. 8 July 2012