Obelisk Bridge, Co. Louth
NATURA IMPACT STATEMENT
Version: 30th July 2020
Tait Business Centre, Dominic Street, Limerick City, Ireland. t. +353 61 313519, f. +353 61 414315 e. [email protected] w. www.ecofact.ie
Obelisk Bridge, Co. Louth – Rehabilitation Works Natura Impact Statement______
EXECUTIVE SUMMARY
If mitigation measures are required for a proposed project (such as the proposed bridge rehabilitation works) to reduce or avoid a significant adverse effect, then Appropriate Assessment (Natura Impact Statement) is required. Louth County Council has proposed works in relation to the rehabilitation of Obelisk Bridge, located near Drogheda in County Louth. The proposed rehabilitation works will require mitigation measures to be in place during the works in order to prevent adverse impacts on the Natura 2000 network. Therefore, the following report provides a NIS and relevant mitigation is set out in this document.
The current document provides a Natura Impact Statement (NIS) and assesses the likely significant effects on the River Boyne and River Blackwater SAC (Site Code: 002299), the River Boyne and River Blackwater SPA (Site Code: 004232), the Boyne Coast and Estuary SAC (Site Code: 0091957) and the Boyne Estuary SPA (Site Code: 004080) arising from the proposed bridge rehabilitation works at Obelisk Bridge, County Louth.
Obelisk Bridge is situated over the main channel of the River Boyne approximately 1.5rkm (River Kilometres) upstream of the M1 crossing of the river, to the west of Drogheda. This site of the proposed works is in the freshwater-tidal section of the Boyne channel and is within the boundaries of both the River Boyne and River Blackwater SAC and the River Boyne and River Blackwater SPA. There is also downstream hydrological connection between the proposed works and both the Boyne Coast and Estuary SAC, located just over 7.5rkm downstream of Obelisk Bridge and the Boyne Estuary SPA, located just over 6.5rkm downstream of the bridge.
The bridge is expected to undergo grit blast cleaning, painting, refurbishment and strengthening works including to the underside of the bridge. Due to the nature of the works over the watercourse there is a risk of water quality impacts in particular as a result of debris / sediment / dust and contaminated run- off entering the watercourse. Such impacts have the potential to adversely affect the qualifying interests of the Natura sites in the immediate vicinity of the site as well as indirectly negatively affecting those of the downstream Natura sites. Potential direct impacts to qualifying interests of the Natura sites identified as being potentially affected that are likely to occur at the subject bridge site are also considered. It is determined that there is potential for the proposed works to cause disturbance / harm of species as well as possible destruction / damage to habitats (in particular to Annex I Alluvial forest habitat which occurs at the site of the proposed works). Mitigation is required to minimise these impacts.
The mitigation measures proposed are considered to be sufficient to ensure that potential impacts, mainly relating to water quality, are minimised. From the evidence presented in the current assessment, it is concluded that the potential direct, indirect and cumulative impacts, that may arise from the proposed upgrade works at Obelisk Bridge, do not have the potential to affect the integrity of the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and the Boyne Estuary SPA.
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TABLE OF CONTENTS 1. INTRODUCTION ...... 5 1.1 CONSULTATION ...... 5 1.2 LEGISLATIVE CONTEXT ...... 5 2. METHODOLOGY ...... 8 2.1 DESKTOP REVIEW ...... 8 2.2 SITE SURVEY ...... 8 2.3 APPROPRIATE ASSESSMENT METHODOLOGY ...... 8 2.3.1 Natura Impact Assessment ...... 9 2.4 CONSULTATION ...... 9 3. DESCRIPTION OF THE PROJECT ...... 10 4. RECEIVING ENVIRONMENT ...... 11 4.1 INTRODUCTION ...... 11 4.1.1 River Boyne ...... 11 4.1.2 Boyne Estuary ...... 12 4.2 INFORMATION SOURCES ON QUALIFYING INTERESTS ...... 12 4.2.1 Fish populations ...... 12 4.2.2 Otters ...... 13 4.2.3 Kingfisher ...... 13 4.2.4 Estuarine bird populations ...... 14 4.3 DESCRIPTION OF NATURA 2000 SITES AFFECTED ...... 14 4.3.1 River Boyne and River Blackwater SAC ...... 17 4.3.2 River Boyne and River Blackwater SPA ...... 19 4.3.3 Boyne Coast and Estuary SAC ...... 19 4.3.4 Boyne Estuary SPA ...... 21 4.4 OTHER DESIGNATIONS ...... 27 5. IMPACT ASSESSMENT ...... 28 5.1 RIVER BOYNE AND RIVER BLACKWATER SAC ...... 28 5.2 RIVER BOYNE AND RIVER BLACKWATER SPA ...... 30 5.3 BOYNE COAST AND ESTUARY SAC ...... 31 5.4 BOYNE ESTUARY SPA ...... 34 6. MITIGATION ...... 40 6.1 DETAILED METHOD STATEMENT AND CEMP ...... 44 6.2 AVOIDANCE ...... 44 6.2.1 Footprint of works ...... 44 6.2.2 Timing of works...... 44 6.3 WATER QUALITY PROTECTION...... 45 6.4 BIOSECURITY ...... 45 6.5 SITE ECOLOGIST ...... 46 7. IMPLICATIONS FOR CONSERVATION OBJECTIVES ...... 46 7.1 CONSERVATION OBJECTIVES FOR THE AFFECTED NATURA 2000 SITES ...... 47 8. CONCLUSION STATEMENT ...... 48 9. OTHER ECOLOGICAL INTERESTS ...... 50 9.1 BATS ...... 50 9.2 CRAYFISH ...... 50 REFERENCES ...... 51 PLATES ...... 54
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APPENDIX 1 SCREENING FOR APPROPRIATE ASSESSMENT MATRIX ...... 57
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1. INTRODUCTION
Louth County Council proposes to carry out rehabilitation works on Obelisk Bridge. This bridge crosses the main channel of the River Boyne to the west of Drogheda Town. This bridge is located within the River Boyne and River Blackwater SAC and the River Boyne and River Blackwater SPA. The Boyne Estuary SPA and Boyne Coast and Estuary SAC are also located just over 6.5rkm and 7.5rkm respectively downstream of the site. The location of the proposed rehabilitation works in relation to Natura 2000 sites within 15km is presented in Figure 1. Ecofact were commissioned by Louth County Council to complete a Natura Impact Statement for the proposed bridge works at Obelisk Bridge. There are four Natura 2000 sites likely to be affected by the proposed works - River Boyne and River Blackwater SAC (Site Code: 002299), River Boyne and River Blackwater SPA (Site Code: 004232), Boyne Coast and Estuary SAC (Site Code: 0091957) and Boyne Estuary SPA (Site Code: 004080). Due to hydrological connection and proximity to the proposed bridge works, there is the potential for direct, indirect and cumulative impacts on these Natura 2000 sites and mitigation is required to protect these sites they are assessed in the current NIS. It is noted that a screening for Appropriate Assessment was not included in the request and Ecofact were engaged only to carry out the current NIS.
An Article 6 Appropriate Assessment is required under the Habitats Directive (92/43/EEC), in instances where a plan or project may give rise to significant effects upon a Natura 2000 site. Natura 2000 sites are those identified as sites of European Community importance designated under the Habitats Directive (1992) and EC Birds Directive (2009/147/EC); transposed into Irish legislation as the European Communities (Birds and Natural Habitats) Regulations 2011 (S.I. 477 of 2011). The Habitats Directive, in combination with the Birds Directive (2009), establishes a network of internationally important sites designated for their ecological status; identified as Special Areas of Conservation (hereafter referred to as SACs) designated under the Habitats Directive for the protection of flora, fauna and habitats and as Special Protection Areas (hereafter referred to as SPAs) designated under the Birds Directive to protect rare, vulnerable and migratory birds. These sites together form a Europe-wide 'Natura 2000' network of designated sites, referred to in this report as Natura 2000 sites.
The preparation of this NIS follows the Habitats Directive 92/43/EEC, Article 6(3) and the guidance published by the National Parks and Wildlife Service (NPWS, 2010) ‘Appropriate Assessment of Plans and Projects in Ireland: Guidance for Planning Authorities’. The current NIS report was prepared by Ecofact Environmental Consultants Ltd. on behalf of Louth County Council and presented to inform the Appropriate Assessment for the proposed bridge works.
1.1 Consultation
The following statutory bodies provided information via publicly available sources for this report:
• National Parks and Wildlife Service (NPWS); • Inland Fisheries Ireland (IFI); • Environmental Protection Agency (EPA);
1.2 Legislative context
The current assessment takes account of Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora - ‘The Habitats Directive’ which was transposed into Irish law by the ‘European Community (Natural Habitats) Regulations 1997’ (S.I. No. 94/1997). The most recent transposition of this legislation in Ireland is the European Communities (Birds and Natural Habitats)
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Regulations 2011 (S.I. No. 477 of 2011). The Birds Directive (2009/147/EC) which is now included in the former Regulations seeks to protect birds of special importance by the designation of SPAs whereas the Habitats Directive does the same for habitats and other species groups within SACs, which are designated or proposed as candidate Special Areas of Conservation (cSACs). It is the responsibility of each member state to designate SPAs and SACs, both of which will form part of Natura 2000, a network of protected areas throughout the European Community. Article 6, paragraphs 3 and 4 of the EC ‘Habitats’ Directive (1992) state that:
6(3) ‘Any plan or project not directly connected with or necessary to the management of the site but likely to have a significant effect thereon, either individually or in combination with other plans or projects, shall be subject to appropriate assessment of its implications for the site in view of the site's conservation objectives. In the light of the conclusions of the assessment of the implications for the site and subject to the provisions of paragraph 4, the competent national authorities shall agree to the plan or project only after having ascertained that it will not adversely affect the integrity of the site concerned and, if appropriate, after having obtained the opinion of the general public.’
6(4) ‘If, in spite of a negative assessment of the implications for the site and in the absence of alternative solutions, a plan or project must nevertheless be carried out for imperative reasons of overriding public interest, including those of a social or economic nature, the Member State shall take all compensatory measures necessary to ensure that the overall coherence of Natura 2000 is protected. It shall inform the Commission of the compensatory measures adopted. Where the site concerned hosts a priority natural habitat type and / or a priority species, the only considerations which may be raised are those relating to human health or public safety, to beneficial consequences of primary importance for the environment or, further to an opinion from the Commission, to other imperative reasons of overriding public interest.’
In addition, the European Court of Justice in Case C-127/02 (the “Waddenzee Ruling”) has made a relevant ruling in relation to Appropriate Assessment and this is reflected in the current assessment:
‘Any plan or project not directly connected with or necessary to the management of the site is to be subject to an appropriate assessment of its implications for the site in view of the site’s conservation objectives if it cannot be excluded, on the basis of objective information, that it will have a significant effect on that site, either individually or in combination with other plans or projects” and that the plan or project may only be authorised “where no reasonable scientific doubt remains as to the absence of such effects.’
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Figure 1 Natura 2000 sites within 15km of Obelisk Bridge, Co. Louth.
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2. METHODOLOGY
2.1 Desktop Review
A desktop study was undertaken to identify the extent and scope of the potentially affected designated Natura 2000 sites within the current study area, in relation to the proposed remedial works at Obelisk Bridge west of Drogheda, Co. Louth. The desktop study identified the conservation interests of the designated sites with respect to the qualifying interests (species and habitats) relevant to the designated sites within the area.
A review of published literature was undertaken in order to collate data on the receiving environment, including aquatic species and habitats of conservation concern in the study area. A range of additional sources of information including scientific reports produced by, and information on the websites of the EPA, NPWS and other agencies were also reviewed. A full bibliography of information sources reviewed is given in the reference section.
2.2 Site Survey
Obelisk Bridge was visited on the 21st June 2020 to conduct field surveys. The proposed remedial works area and environs were inspected for evidence of ecological features of high conservation concern. The flora and fauna at the site of the proposed bridge works were identified and evaluated for ecological importance. The surveys included habitat surveying, mammal surveying, aquatic ecology surveying and bird surveying. General protected species surveys were undertaken to identify any species of ecological importance within the study area. The bridge was surveyed for the presence of otters or other mammals from 50m upstream of the bridge to 50m downstream of the bridge. The area was also inspected for the presence of kingfisher nesting sites along the river channel. The habitats within 50m of the bridge were surveyed to identify any Annex I habitats in the area. The area was also surveyed for the presence of any non-native invasive species. The potential for salmon and lamprey habitat in the river from 50m upstream of the bridge to 50m downstream of the bridge was also assessed.
2.3 Appropriate Assessment Methodology
The preparation of this NIS for Appropriate Assessment follows the guidance published by DoEHLG (2010) ‘Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities’. According to these guidelines, assessing the impacts of a project or plan on a Natura 2000 site is a four staged approach, as described below:
• Stage One: Screening / Test of Significance - The process which identifies the likely impacts upon a Natura 2000 site of a project or plan, either alone or in combination with other projects or plans, and considers whether these impacts are likely to be significant; • Stage Two: Appropriate Assessment - The consideration of the impact of the project or plan on the integrity of the Natura 2000 site, either alone or in combination with other projects or plans, with respect to the site’s structure and function and its conservation objectives. Additionally, where there are adverse impacts, an assessment of the potential mitigation of those impacts; • Stage Three: Assessment of Alternative Solutions - The process which examines alternative ways of achieving the objectives of the project or plan that avoid adverse impacts on the integrity of the Natura 2000 site; and
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• Stage Four: Assessment Where Adverse Impacts Remain - An assessment of compensatory measures where, in the light of an assessment of Imperative Reasons of Overriding Public Interest (IROPI), it is deemed that the project or plan should proceed.
The safeguards set out in Article 6(3) and (4) of the Habitats Directive are triggered not by certainty but by the possibility of significant effects. Thus, in line with the precautionary principle, it is unacceptable to fail to undertake an appropriate assessment on the basis that it is not certain that there are significant effects.
2.3.1 Natura Impact Assessment
A Natura Impact Statement (NIS) considers whether the plan or project, alone or in combination with other projects or plans, will have adverse effects on the integrity of a Natura 2000 site, and includes any mitigation measures necessary to avoid, reduce or offset negative effects. The current report is set out in the format of a NIS and comprises a scientific examination of the plan / project and the relevant Natura 2000 sites; to identify and characterize any possible implications for the site in view of the site’s conservation objectives, structure and function, taking account of in combination effects. The requirements for Appropriate Assessment derive directly from Article 6(3) of the EU Habitats Directive (1992).
Direct and indirect impacts in isolation or in combination with other plans and projects on the identified Natura 2000 sites in view of the sites’ conservation objectives have been examined. Case law of the European Court of Justice (ECJ) has established that Appropriate Assessment must be based on best scientific knowledge in the field. These are the qualifying interests i.e. Annex I habitats, Annex I bird species (EU Birds Directive, incorporated into the EU Habitats Directive) and Annex II species hosted by a site and for which that site has been selected. The conservation objectives for Natura sites (SACs and SPAs) are determined under Article 4 of the Habitats Directive and are intended to ensure that the relevant qualifying interests i.e. Annex I habitats, Annex I bird species and Annex II species present within the designated sites are maintained in a favourable condition. The current assessment of the proposal for rehabilitation works at Obelisk Bridge provides a description of the project and the receiving environment. The conservation objectives of Natura 2000 sites potentially affected by the proposal are listed and potential impacts outlined with respect to the integrity of the Natura 2000 sites. Mitigation measures have been proposed for the protection of the conservation interests and the avoidance of impacts to Natura 2000 sites occurring within the study area.
2.4 Consultation
The following statutory bodies provided information via publicly available sources for this report:
• National Parks and Wildlife Service (NPWS); • Inland Fisheries Ireland (IFI); • Environmental Protection Agency (EPA); • National Biodiversity Data Centre online database
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3. DESCRIPTION OF THE PROJECT
Obelisk Bridge was constructed in 1869. It is a single-span bridge with an overall length of 38.5m and a width out-to-out of 5.87m. The bridge carries a single carriageway unclassified road of approximately 4.88m wide with no kerbs or edge of carriageway markings (Roughan and O'Donovan Consulting Engineers, 2016). The material of the primary members is wrought iron with masonry abutment structures. The type of foundation of the abutment structures is unknown. The lattice girders are part of the superstructure and the minimum lattice girder height is 4.48m. The wearing surface of the bridge is concrete and the type of expansion joint is buried joint. There were four unknown service ducts attached to the deck of the bridge noted in the Inspection Report for the structure (Atkins, 2013).
The structure was inspected by Atkins in 2013 to assess the condition and the damages. The identified damages and required repair works reported in the Atkins inspection are summarised below:
• Bridge surface: Sealing pavement cracks with vegetation in some cracks. • Expansion joints: Reinstate material to repair worn joint. • Parapet/safety barrier: Masonry re-pointing, spot paint repair to parapet/guardrail. Minor vegetation growth along parapets noted. • Embankments/revetments: Routine maintenance cut-back of excessive vegetation. • Wing/spandrel/retaining walls: Dense vegetation and localised water seepage through joints. • Abutments: Good condition apart from algae growth and localised water seepage through joints noted. • Deck/slab/arch/barrel: Repair to structure deck and anti-corrosion protection. • Beams/girders/transverse beams: Steelwork protection due to corroded steel beams (transverse and longitudinal). • Riverbed: Removal of coping debris. • Other elements: Repair under-bridge gantry due to surface corrosion. • Structure in general: Paint and corrosion protection throughout decks and beams.
A later report of the refurbishment options was also produced by Roughan and O'Donovan (2016) which indicates that the minimum requirement for the bridge is for grit blasting and painting to be undertaken, which includes the underside of the bridge and would require the erecting of scaffolding to complete it. The 2016 report also indicates that minor general repairs involving repair of damages wind bracing and north abutment capping stone will be needed along with a new reinforced concrete deck being installed.
It is noted that precise procedures and repair works will need to be confirmed in a detailed method statement prior to works.
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4. RECEIVING ENVIRONMENT
4.1 Introduction
The Obelisk Bridge is located on the 6th order Boyne River (EPA Segment Code: 07_2107) to the west of Drogheda town in County Louth, 1.3km west of the M1 motorway. The bridge is on the border between counties Louth and Meath as the River Boyne forms the border at this point. The bridge is on the Oldbridge Road just over 100m south of the N51, approximately 135m south of Townley Hall Woods and just over 250m south-east of Townley Hall Golf Club. The Boyne Canal runs alongside the main River Boyne at his point at less than 50m south of the main channel.
Obelisk Bridge site is within two designated Natura 2000 sites: the River Boyne and River Blackwater SAC (Site Code: 002299) and the River Boyne and River Blackwater SPA (Site Code: 004232). The River Boyne and River Blackwater SAC is selected for Alkaline fens (7230) and Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) (91E0) habitats, listed on Annex I of the E.U. Habitats Directive. The SAC site is also selected for three aquatic species listed under Annex II of the E.U. Habitats Directive, which are, River lamprey Lampetra fluviatilis (1099), Salmon Salmo salar (1106) and Otter Lutra lutra (1355). This area is selected as a designated SPA under the E.U. Birds Directive with special conservation interest for Kingfisher Alcedo atthis (A229).
Also downstream of the site of the proposed bridge works, in the Boyne Estuary there is another SAC and another SPA on the river. The Boyne Coast and Estuary SAC (Site Code (0091957) is located just over 7.5rkm downstream of the bridge. This SAC is selected for eight Annex I E.U. Habitats Directive: Estuaries (1130), Tidal mudflats and sandflats (1140), Annual vegetation of drift lines (1210), Salicornia mud (1310), Atlantic salt meadows (1330), Embryonic shifting dunes (White dunes) (2110), Marram dunes (Grey dunes) (2130). The Boyne Estuary SPA (Site Code: 004080) is located just over 6.5rkm downstream of Obelisk Bridge. This SPA site is of special conservation interest for Wetland and Waterbirds (A999) and is selected for the protection of the following species: Shelduck Tadorna tadorna (A048), Oystercatcher Haematopus ostralegus (A130), Golden Plover Pluvialis apricaria (A140), Grey Plover Pluvialis squatarola (A141), Lapwing Vanellus vanellus (A142), Knot Calidris canutus (A143), Sanderling Calidris alba (A144), Black-tailed Godwit Limosa limosa (A156), Redshank Tringa totanus (A162), Turnstone Arenaria interpres (A169) and Little Tern Sterna albifrons (A195).
4.1.1 River Boyne
The River Boyne rises in Edenderry, County Kildare and flows in a north-easterly direction through Navan, turning more east at Slane Castle, County Meath. The river becomes a transitional waterbody at Proudfootstown in County Meath, between the Dowth wetland NHA and the 4th order Mattock River (Segment Code: 07_2151) confluence with the Boyne, which is located 1.1rkm upstream of the subject bridge. Approximately 600m upstream of Obelisk Bridge the 2nd order Sheepgrange River (Segment Code: 07_2205) joins the watercourse from the west. The 2nd order Tulaigh_álainn River (Segment Code: 07_2206) flows into the Boyne at Obelisk Bridge from the north.
At the Obelisk Bridge the watercourse is classified as tidal-freshwater habitat, which is the habitat type found at the upstream reaches of transitional water bodies and downstream from the fully non-tidal freshwater ecosystems. Tidal-freshwater areas are within the tidal reaches of a river system but still have very low salinity with freshwater flowing in from upstream.
The EPA carries out biological monitoring at Obelisk Bridge, just downstream of the Tulaigh_álainn confluence. In 2018 a Q-rating of 4 indicating 'Good' water quality was assigned at this monitoring
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station (Station Code: 07B042 200). There is no other freshwater monitoring on the Boyne downstream of this location but there are several transitional water surveillance stations along the channel moving east through Drogheda Town and to the river mouth as the watercourse becomes estuarine. The Boyne River at Drogheda has a Transitional Waterbody WFD Status 2013-2018 of 'Moderate'. The WFD risk assessment of the Boyne Estuary is 'At risk'. The main sources of pressure on the river catchment are from upstream agricultural diffuse and septic tank and landfill pollution (ERBD, 2010). The nearest upstream freshwater monitoring point to the Obelisk Bridge is located 8.2rkm upstream (Station Code: 07B042 150) where a Q-score of 4, equating to 'Good' water quality was recorded in 2012.
4.1.2 Boyne Estuary
The Boyne watercourse continues east from Obelisk Bridge becoming estuarine as it nears the coast. It runs along sections of the County Louth/County Meath border and through Drogheda Town. The River Boyne flows into the Irish Sea to the east of Drogheda Town between Mornington Manor, County Meath and Baltray, County Louth.
Downstream of the M1 motorway crossing, the River Boyne is joined by three tributaries: the 1st order Rathmullan (Segment Code: 07_1900) and the 2nd order Mell (Segment Code: 07_1902) from the north and the 1st order Sheephouse 07 (Segment Code: 07_1904) from the south. The 2nd order Tullyeskar (Segment Code: 07_1906) flows into the Boyne form the north side 4.8rkm downstream of the M1 motorway. Several other tributaries join the Boyne channel as the river flows east towards its mouth. None of these tributaries have recent Q-ratings assigned to them and have not been assigned a River Waterbody WFD Status 2013-2018.
The Boyne Estuary has been assessed as 'Moderate' in terms of water quality and is considered to be 'At risk' of not meeting its water quality objectives. The main source of nutrient input in the Boyne Estuary is the inputs from diffuse and small point sources around the catchment, including significant contribution from the Drogheda WWTP (EPA, 2018). The main pressures on the estuary are upstream agricultural diffuse and septic tank pollution. Heavy modification also affects the estuary (ERBD, 2010).
4.2 Information sources on Qualifying Interests
4.2.1 Fish populations
4.2.1.1 Atlantic Salmon
The River Boyne watercourse is freshwater-tidal habitat at Obelisk Bridge and therefore is unsuitable for salmon spawning, however the Boyne tributaries and headwaters provide the spawning grounds for the species. Atlantic salmon run the River Boyne almost every month of the year. The Boyne is important for salmon as it represents an eastern river which holds large three-sea-winter fish from 20- 30 lb. These fish generally arrive in February, with smaller spring fish (10 lb) arriving in April / May. The grilse usually come in July, water permitting. The river gets a further run of fish in late August and this run would appear to last well after the fishing season. The salmon fishing season lasts from 1st March to 30th September (NPWS, 2014).
4.2.1.2 Lamprey
In 2005 Ecofact carried out lamprey surveying in the River Boyne catchment which confirmed that significant populations of River / Brook lampreys occurred throughout the catchment. River lamprey were found to be the more dominant species in the lower reaches of the river, which is where the subject bridge site is located, and Brook lamprey most likely to be dominant in the up-river areas. The survey
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also noted that Sea lamprey may also be present in the River Boyne lower reaches, although they were not detected during the assessment (Ecofact, 2006).
There were ninety-one sites in the Boyne Catchment surveyed, twenty-seven of which were on the main channel of the River Boyne including at Obelisk Bridge. The site at Obelisk Bridge was among the six sites with the highest densities of lamprey larvae with a density of 27 larvae per m2 recorded in the 2005 surveying. The substrate in this area was predominantly sand and silt according to the Boyne lamprey assessment.
Lamprey stocks in the main channel of the Boyne downstream of Navan are in a very healthy state with high densities of larvae present in all suitable habitats investigated in the 2005 survey. Several cohorts of juvenile lampreys were also present at each site investigated along this section confirming that regular recruitment occurs along the channel. Lamprey stocks in other areas of the Boyne catchment were less abundant and diverse but were still considered to be at a favourable conservation status level in most parts with the exception of some tributaries of the middle Boyne (Ecofact 2006).
In the past the River Boyne has been subject to major arterial drainage works which may have impacted on lamprey production in the catchment significantly in the past. According to Ecofact (2006) areas affected by the arterial drainage scheme have a much reduced availability of lamprey habitats and that little physical recovery has occurred on many of the smaller channels over the past 20 years. The availability of optimal lamprey nursery habitat is also considered to be restricted in many areas of the catchment because of this drainage. The existing lamprey habitat in the catchment is under threat from pollution and drainage maintenance. The highest densities of lamprey recorded in the survey were in the lower Boyne, which was also the most polluted area of the catchment surveyed The lamprey ammocoetes are fairly tolerant to moderate levels of organic pollution but Ecofact (2005) states that if pollution in the lower Boynes increases it is likely that lamprey will eventually be lost.
4.2.2 Otters
Between 1980/81 and 2010/11 a total of 5 otter surveys were conducted in the Boyne Catchment. A decline in Otter incidence by 37.3% was reported between 1980/81 and 2004/05. There was subsequent increases (42.8% by 2004/05 and 17.7% from 2008 to 2010), although these were not found to be statistically significant (Reid et al., 2013).
4.2.3 Kingfisher
Kingfisher favours slow-moving, quiet streams / rivers / canals. Water quality, availability of suitable vertical banks for digging nest tunnels in and perches are important factors affecting the overall suitability of river systems for Kingfisher. Kingfisher also relies on adequate fish populations which this species feeds on as well as large aquatic insects.
The Boyne system has reasonably high numbers of Kingfisher according to Cummins et al. (2010). There are 15-19 Kingfisher territories on the Boyne, a density of 0.12 territories per kilometer according to the 2010 assessment of Kingfisher distribution. Approximately 0.11 nests per kilometer was also reported for the Boyne system. The relative abundance of territories overall in the Boyne system was considered to be unchanged between 2008 and 2010. However, shifts in distribution found an increase in territory abundance downstream of the Blackwater confluence on the Boyne. Based on the 2010 assessment of Kingfisher distribution the area around Obelisk Bridge is 'possible' Kingfisher territory. There is 'probable' Kingfisher territory with records of Kingfisher nests a short distance upstream of the bridge at Dowth Wetland.
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4.2.4 Estuarine bird populations
The Boyne estuary is of considerable ornithological importance, particularly for wintering waterfowl. The main area that supports the estuarine bird populations of the Boyne is within the boundaries of the Boyne Estuary SPA. According to the Irish Wetland Bird Surveys (I-Webs), database a total of fifty-four waterbird species have been recorded within the Boyne Estuary count area during the data period 1994/95 – 2009/10. There were twenty-three of these species which occurred on a regular basis within the Boyne Estuary, ten of which are listed as Special Conservation Interests of the designated Boyne Estuary SPA. This designated site is located downstream of the subject bridge site, to the east of Drogheda Town and comprises most of the estuary of the Boyne River. The Boyne Estuary is the second most important estuary for wintering birds on the Louth-Meath coastline. Black-tailed Godwit occur in the SPA in internationally important numbers and nine other species occur in nationally important numbers. Of particular significance is that three species that regularly occur, Golden Plover, Bar-tailed Godwit and Little Tern are listed on Annex I of the E.U. Birds Directive. Part of the Boyne Estuary SPA is also a Wildfowl Sanctuary (NPWS, 2015).
4.3 Description of Natura 2000 sites affected
The locations of the all Natura 2000 sites within a 15km radius of Obelsik Bridge are shown in Figure 1. Figure 2 shows a zoomed in map of the site location of the proposed bridge works with the Natura 2000 sites in the immediate vicinity of the bridge outlined. Figure 3 shows the woodland habitat in the general vicinity of the bridge and provides a 50m buffer area boundary around the bridge also.
Ecofact were commissioned to carry out NIS only for the proposed bridge works, prior screening for Appropriate Assessment is not included in this appointment. The following Natura 2000 sites are assessed in the current NIS: River Boyne and River Blackwater SAC (Site Code: 002299), River Boyne and River Blackwater SPA (Site Code: 004232), Boyne Coast and Estuary SAC (Site Code: 0091957) and Boyne Estuary SPA (Site Code: 004080). These sites are included as it is considered that these sites could all potentially be affected by the proposed works due to close proximity and hydrological connection to the proposed works area (see Screening for Appropriate Assessment Matrix in Appendix 1). The qualifying interests of these Natura sites with regard to their presence within the study area and their conservation status are discussed below.
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Figure 2 Location of Obelisk Bridge showing SACs and SPAs in the vicinity.
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Figure 3 Location of Obelisk Bridge showing the Natura 2000 sites and the woodland habitats from the National Woodlands 2010 dataset in the vicinity, a 50m buffer area around the subject bridge is also outlined.
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4.3.1 River Boyne and River Blackwater SAC
The River Boyne and River Blackwater SAC is selected for Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) (91E0) as well as for Alkaline fens (7230) which are listed in Annex I of the E.U. Habitats Directive, 1992. Alluvial wet woodland habitat is a priority habitat on Annex I of the Directive. Priority habitats are those which are considered to require particular protection because their global distribution largely falls within the E.U. and they are in danger of disappearance. As well as for these habitats, the SAC has been selected for fish and mammal species which are listed under Annex II of the EU Habitats Directive. These species are River Lamprey Lampetra fluviatilis (1099), Atlantic Salmon Salmo salar (1106) and Eurasian Otter Lutra lutra (1355). The qualifying interests of the River Boyne and River Blackwater SAC are presented in Table 2 and are discussed individually below. The site synopsis for the River Boyne and River Blackwater SAC is included in the Appendix 2. The NPWS details the conservation objectives of the River Boyne and River Blackwater SAC (NPWS, 2020a)
Table 1 Qualifying interests of the River Boyne and River Blackwater SAC, their occurrence / potential to occur in the vicinity to Obelisk Bridge. Natura Qualifying interests Evaluation of potential to occur within Code the proposed works area
7230 Alkaline fens This habitat is found concentrated around lakes upstream. It is not present at the subject bridge site and won't be affected by the proposed works. 91E0 Alluvial forests with Alnus glutinosa and Fraxinus This habitat is present at the excelsior (Alno-Padion, Alnion incanae, Salicion proposed works area on the albae)* downstream side of the bridge along
Annex I I Annex Habitats the south bank of the river. 1106 Atlantic salmon (Salmo salar) Adult Atlantic salmon are expected to be found at the subject bridge site. There is potential for direct impacts. 1099 River lamprey River lamprey are present at the (Lampetra fluviatilis) subject bridge site, juveniles are likely to be buried in the mud/silt.
There is potential for direct impacts. 1355 Otter (Lutra lutra) No otter holts were present at the subject bridge site but are likely to commute and forage along the Boyne at the proposed works area.
Annex II II Annex Species There is potential for direct impacts.
4.3.1.1 Annex I Habitats
The site is a SAC selected for alluvial wet woodlands which is a priority habitat on Annex I of the E.U. Habitats Directive. The designated site is also selected as an SAC for alkaline fen habitat, listed on Annex I of the E.U. Habitats Directive.
4.3.1.1.1 Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno- Padion, Alnion incanae, Salicion albae) (91E0)
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Alluvial Forests are typically woodlands of alder (Alnus glutinosa) and ash (Fraxinus excelsior), often with willow (Salix spp.) and sometimes oak (Quercus robur). This habitat occurs in areas subject to periodic flooding along rivers and on lake shores.
There is a 64,662m2 area of alluvial forest along the south bank of the river at this location and stretching downstream, according on NBDC online maps of the National Woodlands 2010 dataset. Approximately 700m downstream there is a 102,859m2 area of this habitat on the opposite bank stretching down to just downstream of the M1.
4.3.1.1.2 Alkaline fens (7230)
Alkaline fens habitat consists of a complex assemblage of vegetation types which are characteristic of sites where there is tufa and/or peat formation with a high water table and a calcareous base-rich water supply. The core vegetation type is short sedge mire.
The main areas of alkaline fen in this SAC are concentrated in the vicinity of Lough Shesk, Freehan Lough and Newtown Lough (NPWS, 2014). This habitat type is not present at Obelisk Bridge.
4.3.1.2 Annex II Species
Species listed as qualifying interests of the River Boyne and River Blackwater SAC and listed on Annex II of the E.U. Habitats Directive include: River lamprey Lampetra fluviatilis, Atlantic salmon Salmo salar, Otter Lutra lutra.
4.3.1.2.1 River lamprey (1099)
River lamprey is an anadromous species, spending part of its life cycle in the marine environment and returning to natal watercourses to spawn. Spawning of river lamprey usually begins in March and April (Morris & Maitland, 1987).
This species occurs in the River Boyne at Obelisk Bridge. Lamprey larvae is likely to be present in the mud / silt at the subject bridge site. Large numbers of lamprey were previously recorded at the Obelisk Bridge in a survey of the River Boyne in 2005 (Ecofact, 2006).
4.3.1.2.2 Atlantic salmon (1106)
Salmon pass through this part of the River Boyne at Obelisk Bridge during their migration to sea and also on their spawning run from the sea to the spawning habitat upstream of the bridge in the freshwater stretches of the Boyne and its tributaries.
This species is present within in the River Boyne at Obelisk Bridge.
4.3.1.2.3 Otter (1355)
Otters have two basic requirements: aquatic prey and safe refuges where they can rest. This species is dependent on fish stocks which are ultimately dependent on water quality.
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No otter holts were found in the vicinity of the proposed works area. However, there was evidence of Otter activity at the subject bridge site and it is considered highly likely that this species uses the subject bridge site for foraging and commuting.
4.3.2 River Boyne and River Blackwater SPA
The River Boyne and River Blackwater SPA is selected for the protection of Kingfisher Alcedo atthis (A229) listed under Annex II of the E.U. Birds Directive. The qualifying interest of the River Boyne and River Blackwater SPA is presented in Table 3 and is discussed below. The NPWS details the conservation objectives of the River Boyne and River Blackwater SPA (NPWS, 2020b).
Table 2 Qualifying interests of the River Boyne and River Blackwater SPA, their occurrence / potential to occur in the vicinity of Obelisk Bridge. Natura Qualifying interests Evaluation of potential to occur within the proposed works area Code A229 Kingfisher Alcedo atthis Kingfisher may occur foraging along the channel of the river at Obelisk Bridge. There was no suitable nesting banks identified in the vicinity of the bridge.
4.3.2.1 Species
4.3.2.1.1 Kingfisher Alcedo atthis (A229)
This species is listed under the Annex I of the EU Birds Directive.
No evidence of Kingfisher nests were found in the immediate vicinity of Obelisk Bridge. However, this species occurs along the River Boyne in this area and is likely to be present at / use the proposed works area.
4.3.3 Boyne Coast and Estuary SAC
The Boyne Coast and Estuary SAC is selected for eight Annex I E.U. Habitats Directive: Estuaries (1130), Tidal mudflats and sandflats (1140), Annual vegetation of drift lines (1210), Salicornia mud (1310), Atlantic salt meadows (1330), Embryonic shifting dunes (White dunes) (2110), Marram dunes (Grey dunes) (2130). The qualifying interests of the Boyne Coast and Estuary SAC are presented in Table 4 and are discussed individually below. The NPWS details the conservation objectives of the Boyne Coast and Estuary SAC (NPWS, 2012).
Table 3 Qualifying interests of the Boyne Coast and Estuary SAC, their occurrence / potential to occur in the vicinity of Obelisk Bridge. Natura Qualifying interests Evaluation of potential to occur Code within the proposed works area
1130 Estuaries The channel at Obelisk Bridge is freshwater tidal habitat. The channel becomes estuarine further downstream near the coast at Drogheda. There is a
Annex I I Annex Habitats pathway for affects.
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Natura Qualifying interests Evaluation of potential to occur Code within the proposed works area
1140 Tidal mudflats and sandflats Does not occur at the site but occurs c. 7.5rkm downstream. There is a pathway for affects. 1210 Annual vegetation of drift lines Does not occur at the site but occurs c. 8rkm downstream. There is a pathway for affects. 1310 Salicornia mud Does not occur at the site but occurs c. 8.5rkm downstream. There is a pathway for affects. 1330 Atlantic salt meadows Does not occur at the site but occurs c. 8rkm downstream. There is a pathway for affects. 2110 Embryonic shifting dunes Does not occur at the site but occurs c. 12rkm downstream. There is a pathway for affects. 2120 Shifting dunes along the shoreline with Does not occur at the site but Ammophila arenaria (White dunes) occurs c. 12rkmdownstream. There is a pathway for affects. 2130 Marram dunes (Grey dunes)* Does not occur at the site but occurs c. 11rkm downstream. There is a pathway for affects.
4.3.3.1 Annex I Habitats
4.3.3.1.1 Estuaries (1130)
The estuary habitat of the Boyne Coast and Estuary SAC occurs just over 7.5rkm downstream of Obelisk Bridge from Drogheda Port Company out to the mouth of the River Boyne between Baltray and Mornington, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012c).
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.2 Tidal mudflats and sandflats (1140)
This habitat occurs just over 7.5rkm downstream of Obelisk Bridge, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012c). This habitat dominates both edges of the river from this point out to the mouth of the River Boyne and stretches along the coast north and south of the river mouth at Baltray and Mornington.
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.3 Annual vegetation of drift lines (1210)
This habitat type occurs at the north side of the mouth of the River Boyne at Baltray, approximately 12.5rkm downstream.
This habitat does not occur in the vicinity of the proposed project.
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4.3.3.1.4 Salicornia mud (1310)
The nearest section of this habitat type is approximately 8.5rkm downstream and becomes more frequent particularly at the north side of the river at a distance of just over 9rkm downstream of Obelisk Bridge, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012b).
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.5 Atlantic salt meadows (1330)
This habitat occurs approximately 8rkm downstream. It occurs frequently from this point along both banks of the river out towards the mouth of the River Boyne, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012b).
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.6 Embryonic shifting dunes (2110)
This habitat type occurs at the coast at either side of the mouth of the River Boyne, approximately 12rkm downstream, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012b).
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.7 Shifting dunes along the shoreline with Ammophila arenaria (White dunes) (2120)
This habitat type occurs at the coast at either side of the mouth of the River Boyne, approximately 12rkm downstream, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012b).
This habitat does not occur in the vicinity of the proposed project.
4.3.3.1.8 Marram dunes (Grey dunes) (2130)
Grey dunes habitat occurs approximately 11rkm downstream of Obelisk Bridge and along both banks at the mouth of the river, as shown in the habitat maps of the SAC conservation objectives supporting documents (NPWS, 2012b).
This habitat does not occur in the vicinity of the proposed project.
4.3.4 Boyne Estuary SPA
This designated site is of special conservation interest for Wetland and Waterbirds (A999) and is selected for the protection of the following species: Shelduck Tadorna tadorna (A048), Oystercatcher
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Haematopus ostralegus (A130), Golden Plover Pluvialis apricaria (A140), Grey Plover Pluvialis squatarola (A141), Lapwing Vanellus vanellus (A142), Knot Calidris canutus (A143), Sanderling Calidris alba (A144), Black-tailed Godwit Limosa limosa (A156), Redshank Tringa totanus (A162), Turnstone Arenaria interpres (A169) and Little Tern Sterna albifrons (A195). The Boyne Estuary is the second most important estuary for wintering birds on the Louth-Meath coastline. The qualifying interests of the Boyne Estuary SPA are presented in Table 5 and are discussed individually below. The NPWS details the conservation objectives of the Boyne Estuary SPA (NPWS, 2013).
Table 4 Qualifying interests of the Boyne Estuary SPA, their occurrence / potential to occur in the vicinity of Obelisk Bridge. Natura Qualifying interests Evaluation of potential to occur within the Code proposed works area
A999 Wetland and Waterbirds The main wetland areas that support the waterbird population of the Boyne Estuary is concentrated downstream along the estuary between Drogheda and
Habitats the coast. A048 Shelduck Tadorna tadorna Possible to be found in the river at the subject bridge site but it is unlikely as it tends to occur at the coast. A130 Oystercatcher Haematopus ostralegus Unlikely to be occur at the subject bridge site as the intertidal flats of the estuary downstream of Drogheda are more suitable. A140 Golden Plover Pluvialis apricaria Possible to be found in the general area of the subject bridge site but it is not considered to be more suitable than the available habitat in the estuary downstream. A141 Grey Plover Pluvialis squatarola Unlikely to be occur in the freshwater- tidal part of the river at the subject bridge site as this is a coastal species. A142 Lapwing Vanellus vanellus Possible to occur in the general vicinity of the subject bridge site. However, the proposed works area is not considered to be more suitable than the estuarine area downstream of Drogheda which supports nationally important numbers. A143 Knot Calidris canutus Unlikely to be occur in the freshwater- tidal part of the river at the subject bridge site as this is a coastal species. A144 Sanderling Calidris alba Unlikely to occur at the subject bridge site as this species mainly occur along the sandy shorelines along the coast to the east of Drogheda. A156 Black-tailed Godwit Limosa limosa Possible to occur in the general vicinity of the subject bridge site but it is not considered an important area as there is
Species favourable habitat in the estuary which
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Natura Qualifying interests Evaluation of potential to occur within the Code proposed works area
supports internationally important numbers. A162 Redshank Tringa totanus Unlikely to occur at the subject bridge site as there are more favourable intertidal foraging areas in the estuary downstream of Drogheda. A169 Turnstone Arenaria interpres Unlikely to be found at that subject bridge site due to the absence of suitable habitat. This coastal species occurs near the river mouth and at the coast east of Drogheda. A195 Little Tern Sterna albifrons Does not occur at the subject bridge site as this is a strictly coastal species and occurs at the coast at the mouth of the river to the east of Drogheda.
4.3.4.1 Habitats
4.3.4.1.1 Wetland and Waterbirds (A999)
The downstream wetlands of the Boyne Estuary are of significant importance for wintering waterfowl. This habitat supports internationally important numbers of Black-tailed Godwit and nine other species in nationally important numbers. Of particular significance is that two of the wintering species supported in the Boyne Estuary, Golden Plover and Bar-tailed Godwit are listed on Annex I of the E.U. Birds Directive. Little Tern is also listed on Annex I of this directive.
The subject bridge site is in the freshwater-tidal part of the River Boyne, upstream of the busy town of Drogheda does not provide optimal habitat for waterbird foraging and/or roosting. The designated wetland and waterbirds area is present just over 6.5rkm downstream of Obelisk Bridge.
4.3.4.2 Species
4.3.4.2.1 Shelduck Tadorna tadorna (A048)
This species occurs in nationally important numbers in the Boyne Estuary SPA.
Shelduck is mainly a coastal species but can occur inland on flooded gravel areas with sandy shores and gravel banks also. Shelducks can forage in a variety of ways from scything their bill through wet mud on exposed tidal flats, to dabbling and scything in shallow water and up-ending in deeper waters. They can therefore forage throughout the tidal cycle. However, most records of foraging Shelduck in the Boyne Estuary were of intertidal foraging (NPWS, 2012a). The small gastropod Hydrobia ulvae, is a favoured prey of Shelduck, and is found in moderate abundances in the mudflats of the Boyne Estuary, which occur most extensively along the south shore of the estuary from Mornington to Burrow Point (NPWS, 2011b).
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This area of the Boyne at the subject bridge site is not considered to be of significant importance for this species as the habitat is not considered optimal for the species compared to other parts downstream in the estuary. This species tends to occur in the more favourable habitat in the estuary downstream of Drogheda, over 6.5rkm downstream of the subject bridge.
4.3.4.2.2 Oystercatcher Haematopus ostralegus (A130)
This species occurs in nationally important numbers in the Boyne Estuary SPA.
Oystercatcher is a wading bird species that forages primarily on tidal flats feeding on cockles and mussels in estuaries. It is mainly a coastal species and can be found foraging along non-estuarine coastline or terrestrially, where they eat earthworms also (NPWS, 2012a).
This freshwater-tidal area of the Boyne is not considered to be of significant importance for this species as there is more favourable habitat that would be preferred by this wading bird in the estuary downstream of Drogheda, over 6.5rkm downstream of the proposed works.
4.3.4.2.3 Golden Plover Pluvialis apricaria (A140)
This species occurs in nationally important numbers in the Boyne Estuary SPA.
This species is listed under Annex I of the EU Birds Directive also.
Golden Plovers feed primarily within agricultural grassland and arable land. Tidal flats are used more as a roosting/resting habitat and the birds tend to favour large, open tidal flats. Golden Plovers tend to occur in large aggregations when observed upon tidal flats. Intertidal feeding is observed to a greater degree during cold weather periods when grassland feeding areas are frozen over (NPWS, 2012a).
It is possible for this species to occur on grassland in the locality of Obelisk Bridge however, there were none present in the vicinity of the proposed works area at the time of the site visit. This area of the Boyne at Obelisk Bridge is not considered to be of significant importance for this species. There is favourable habitat located further downstream where this species flocks along the estuary to the east of Drogheda, over 9rkm downstream of the proposed works. There is not considered to be any major attraction to areas upstream of Drogheda compared to the estuary downstream of the town for Golden Plover.
4.3.4.2.4 Grey Plover Pluvialis squatarola (A141)
This species occurs in nationally important numbers in the Boyne Estuary SPA.
Grey plover occurs as both passage and wintering birds in Ireland. Grey Plover is a coastal species mainly forage intertidally (NPWS, 2012a).
This freshwater-tidal area of the Boyne is not considered to be of significant importance for this species which occur in large numbers in the more favourable habitat in the estuary downstream of Drogheda, approximately 12rkm downstream of the proposed works.
4.3.4.2.5 Lapwing Vanellus vanellus (A142)
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This species occurs in nationally important numbers in the Boyne Estuary SPA. The conservation condition of the species is currently considered as 'Unfavourable' in this SPA (NPWS, 2012a).
Lapwings are traditionally considered as ‘inland’ waders and can be observed across a wide variety of habitats, principally using lowland farmland and freshwater wetlands (e.g. turloughs and callows) but also coastal wetlands. Estuaries are typically used as roosting areas where large flocks may be observed roosting upon the tidal flats but coastal areas will also be used to a greater degree during cold weather events when farmland and freshwater habitats freeze over (NPWS, 2012a). There is evidence in the UK that utilisation of coastal habitats has increased, as well as an increase in intertidal feeding (Gillings et al. 2006). Foraging distribution records of Lapwing in the Boyne Estuary during the winter period 2011/12 showed that foraging mainly occurred intertidally (NPWS, 2012a) on 'intertidal mud and fine sands dominated by Hediste diversicolor and Corophium volutator’ (NPWS, 2011).
Lapwing are widespread, particularly in wet lowland areas. It is therefore possible for this species to occur at the freshwater-tidal area of the Boyne at the proposed Bridge works area. However, there is not considered to be any major attraction for Lapwing at the subject bridge site compared the favourable habitat downstream of Drogheda where the species occurs in nationally important numbers along the intertidal and supratidal habitats along the banks of the Boyne Estuary, over 6.5rkm downstream of the proposed works (NPWS, 2012a).
4.3.4.2.6 Knot Calidris canutus (A143)
This species occurs in nationally important numbers in the Boyne Estuary SPA (NPWS, 2012a).
Knot is a specialist intertidal forager, favouring estuarine sites with extensive area of muddy sand. Its winter distribution is entirely coastal. The Knot population in the Boyne Estuary tend to be concentrated near the mouth of the river and along the coast in large flocks (NPWS, 2012a).
This freshwater-tidal area of the Boyne is not considered to be of significant importance for this species which occur in the more favourable habitat in the estuary downstream of Drogheda and at the coast at the mouth of the river. The main area where Knot tends to be found in the Boyne is from approximately 10rkm downstream of the proposed works and eastwards to the coast (NPWS, 2012a).
4.3.4.2.7 Sanderling Calidris alba (A144)
This species occurs in nationally important numbers in this the Boyne Estuary SPA.
Sanderling occurs in Ireland as wintering and passage birds. During the non-breeding season Sanderlings can be found in a variety of coastal habitats but are characteristic of sandy shorelines (strands), where they forage in small flocks at the edge of the tide. In the Boyne Estuary they forage mainly at Lady's Finger and Baltray at the coast, east of Drogheda (NPWS, 2012a) on fine sand sediments dominated by bivalves (NPWS, 2011).
This freshwater-tidal area of the Boyne is not considered to be of significant importance for this species which occur in the more favourable habitat at the coast downstream of Drogheda, approximately 12rkm downstream of the proposed works.
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4.3.4.2.8 Black-tailed Godwit Limosa limosa (A156)
This species occurs in internationally important numbers in the Boyne Estuary SPA.
Black-tailed Godwit is a wading bird species that forages within intertidal flats in estuaries and estuarine coasts. Particularly suitable foraging grounds for this species are noted to occur along the south shore of the Boyne Estuary from Mornington to Burrow Point (NPWS, 2012a). This species can also occur inland on wet grassland sand river deltas.
It is possible for Black-tailed Godwit to occur in the locality of Obelisk Bridge, however, the proposed works area is not considered to be of significant importance for this species. The habitat at the coast near the mouth of the Boyne downstream of Drogheda is considered more favourable habitat for this species and it is therefore not considered likely for it to be attracted upstream to the subject bridge site. The Boyne Black-tailed Godwit population is supported mainly in the estuary habitat over 6.5rkm downstream of the proposed works.
4.3.4.2.9 Redshank Tringa totanus (A162)
This species occurs in nationally important numbers in the Boyne Estuary SPA.
Redshank favours mudflats, large estuaries and inlets. This species forages mainly within the muddier areas of intertidal mudflats in the Boyne Estuary. The suitable mudflats of ‘intertidal mud and fine sands dominated by Hediste diversicolor and Corophium volutator’ (NPWS, 2011b) are most extensive along the southern shore of the estuary from Mornington to Burrow Point (NPWS, 2012a).
The freshwater-tidal area of the Boyne at the subject bridge site is not considered to be of significant importance for this species which occurs in the more favourable habitat in the estuary downstream of Drogheda, over 6.5rkm downstream of the proposed works.
4.3.4.2.10 Turnstone Arenaria interpres (A169)
This species occurs in nationally important numbers in this the Boyne Estuary SPA. The conservation condition of the species is currently considered as 'Unfavourable' in this SPA (NPWS, 2012a).
Turnstone is coastal species which does not breed in Ireland. Wintering Turnstones have a widespread distribution in Ireland and are a familiar species of open, non-estuarine, rocky shorelines although they do occur regularly occur within estuaries too (NPWS, 2012a).
This species is associated with shorelines with rocky substratum, particularly those with algal wrack zones. The subject bridge site is considered to be too far inland and there is no suitable rocky shore foraging areas here to be of any importance to Turnstone. This area of the Boyne at the subject bridge site is therefore not considered to be of significant importance for this species which occur in the more suitable habitat downstream in the estuary to the east of Drogheda and approximately 10rkm downstream of the proposed works.
4.3.4.2.11 Little Tern Sterna albifrons (A195)
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This species has bred in the Boyne Estuary SPA since 1984, but breeding numbers and fledging success has been variable over the years (NPWS, 2015).
This species is listed under Annex I of the EU Birds Directive also.
Little tern is strictly a coastal species. This freshwater-tidal area of the Boyne is therefore not of any importance for this species which occur in the more favourable habitat at the coast to the east of Drogheda, approximately 12rkm downstream of the proposed works.
4.4 Other Designations
The River Boyne is also a designated Salmonid Water under the European Communities (Quality of Salmonid Waters) Regulations, 1988 (S.I. No. 293/1988). According to the River Boyne and River Blackwater SAC site synopsis, the Boyne and its tributaries are considered one of Ireland’s premier game fisheries and offer a wide range of angling from fishing for spring salmon and grilse to seatrout fishing and extensive brown trout fishing. Atlantic salmon (Salmo salar) use the tributaries and headwaters as spawning grounds. O’Grady (1998) reported that spawning sites for both salmon and trout are confined principally to the tributaries due to very limited gravel deposits in the main channel. O’Grady (1998) states that the tributaries function as nursery areas for salmonids and the larger of these channels, and the main Boyne channel, support substantial populations of adult brown trout and salmon parr. Adult salmon In the River Boyne are mainly found downstream of Navan and seldom move upstream of this point in the channel until late in the year, after the angling season (O’Grady 1998).
Obelisk Bridge is within a Natural Heritage Area, the Boyne River Islands NHA (Site Code: 001862). This NHA site starts at Obelisk Bridge and stretches downstream past the M1 crossing of the river. King William's Glen NHA (Site Code: 001804) is located to the north side of the nearby N51 road, approximately 135m north of the bridge. Dowth Wetland NHA (Site Code: 001861) is located on the west bank of the Boyne channel a small distance, less than 1.5rkm, upstream of the bridge also.
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5. IMPACT ASSESSMENT
In this section the impact of the project / plan affecting the integrity of a Natura 2000 site is considered with respect to the conservation objectives of the designated site. Integrity is defined as: ‘the coherence of the site’s ecological structure and function, across its whole area, or the habitats, complex of habitats and/or populations of species for which the site is or will be classified’. Therefore, the integrity of a Natura 2000 site is principally related to the structure and function of the site with regard to its Annex I habitats and Annex II species listed as the qualifying interests. The conservation status of these qualifying interests comprises the primary conservation objectives for all designated Natura 2000 sites.
5.1 River Boyne and River Blackwater SAC
The qualifying interests of the River Boyne and River Blackwater SAC are presented in Table 6 with the potential impacts of the proposed bridge rehabilitation works on each and the relevant type of mitigation measures required identified too. The qualifying interests are discussed individually below in terms of the potential impacts that could arise from the proposed works.
Table 5 Potential impacts on qualifying interests of the River Boyne and River Blackwater SAC that have the potential to be affected by the proposed works at Obelisk Bridge. Natura Qualifying interests Impacts Code 7230 Alkaline fens None 91E0 Alluvial forests with Alnus Alluvial forest is present in the River Boyne in the
glutinosa and Fraxinus vicinity of the proposed works; there is potential for excelsior (Alno-Padion, direct damage and invasive species and water Alnion incanae, Salicion quality impacts.
Annex I I Annex Habitats albae)* 1106 Atlantic salmon (Salmo salar) Salmon is likely to be present at the proposed works site; there is potential for disturbance impacts, invasive species and water quality impacts. 1099 River lamprey River lamprey is likely to be present at the proposed (Lampetra fluviatilis) works area; there is potential for disturbance
impacts, invasive species and water quality impacts. 1355 Otter (Lutra lutra) No holts are present at the proposed works site, however Otter are likely to pass through this stretch of river for foraging / commuting; there is potential for disturbance impacts, invasive species and water
Annex II II Annex Species quality impacts.
5.1.1 Annex I Habitats
5.1.1.1 Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno- Padion, Alnion incanae, Salicion albae) (91E0)
Alluvial forest is an important priority Annex I E.U. Habitats directive habitat, and one of the qualifying interests of the River Boyne and River Blackwater SAC. This habitat is present at the proposed works area. At this point of the river the wet woodland habitat is present along the south bank of the river at the downstream side of the bridge. Due to the proximity to the proposed works on Obelisk Bridge there is potential for direct adverse impacts of this important habitat. If access to the bridge / river was obtained through this area it is likely that damage would be caused to the vegetation especially if vehicles and machinery were required for the works. There is also a risk that equipment and vehicles
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used at the proposed works site could introduce invasive species to the habitats if they are not cleaned and treated appropriately before arriving at site.
In addition, depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there may be a risk of water quality impacts. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works and residue / debris from blast cleaning of the bridge surface. There is potential for water quality impacts to affect the Alluvial forest directly at the subject bridge site due to contaminated run-off entering the adjacent wet woodland; and indirectly affecting the downstream areas of the habitat stretching down on the north bank of the river also past the M1 motorway crossing of the river.
5.1.2 Annex II Species
5.1.2.1 River lamprey (1099)
River lampreys occur in the River Boyne at the proposed works site. Therefore, they have the potential to be affected by water quality and disturbance impacts arising from the proposed works, both directly and indirectly. Juvenile lampreys burrow into silt and can be killed easily by machines tracking over their habitats where instream works are required for such bridge rehabilitation works. Similarly, if areas of the river under the bridge are dewatered for repair works, lampreys will become stranded and will die.
Direct disturbance of spawning lampreys can also occur if instream works are undertaken during the lamprey spawning seasons.
In addition, depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there may be a risk of water quality impacts. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning. Any water pollution will affect lampreys and habitats at this subject bridge site and downstream. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
5.1.2.2 Atlantic salmon (1106)
The River Boyne is known to support substantial salmon populations. Poor water quality would affect the conservation status of salmon in the River Boyne. Adult salmon are present in the River at Obelisk Bridge. Atlantic salmon have the potential to be affected by disturbance and water quality impacts arising from the proposed works at the bridge. Direct disturbance impacts are likely to arise if any instream works are required, disturbance would be particularly significant during the salmon close season when the fish move upstream past the bridge to freshwater areas to spawn.
There may be a risk of water quality impacts from the proposed works, depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works). Such impacts can arise from an increase in suspended solids in the watercourse which can be generated by
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the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood. Any water pollution will affect salmon and habitat quality of salmon at this subject bridge site and in this transitional waterbody in general.
5.1.2.3 Otter (1355)
No Otter holts exist 50m upstream or downstream at the proposed works site; however, signs of Otter activity was noted. Otters occur on the River Boyne and it is probable that this area of the river is used for foraging / commuting.
Therefore, there is the potential for water quality impacts and disturbance impacts on Otter to arise as a result of the proposed works. Direct disturbance impacts are not considered likely to be significant as works are expected to take place during daytime hours when Otters are not active at the subject bridge site. However, works under the bridge could affect Otters moving upstream and downstream through the bridge if large sections were to be closed off for the works.
Indirect water quality impacts could potentially affect fish populations in the river also which are a food source for this species. Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there may be a risk of water quality impacts. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning. Any water pollution will affect otters and their habitat quality at this subject bridge site and in the transitional waterbody section of the Boyne on general. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood. This would have a severe impact on fish populations which are a food source for Otter.
5.2 River Boyne and River Blackwater SPA
The qualifying interest of the River Boyne and River Blackwater SPA is presented in Table 7 with the potential impacts of the proposed bridge rehabilitation works on it and the relevant type of mitigation measures required identified too. The qualifying interest is discussed individually below in terms of the potential impacts that could arise from the proposed works.
Table 6 Potential impacts on qualifying interests of the River Boyne and River Blackwater SPA that have the potential to be affected by the proposed works at Obelisk Bridge. Natura Qualifying interests Impacts Code Species A229 Kingfisher Alcedo atthis No nests were present at the proposed works site but may use the site; there is potential for disturbance impacts, invasive species and water quality impacts.
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5.2.1 Species
5.2.1.1 Kingfisher Alcedo atthis (A229)
No Kingfisher nests exist 50m upstream or downstream at the proposed works site; however, this species is known to occur along the River Boyne upstream of the M1 motorway crossing of the river. It is probable that this area of the river is used for foraging / commuting by Kingfishers.
Therefore, there is the potential for water quality impacts and disturbance impacts on Kingfisher to arise as a result of the proposed works. Kingfishers are generally most active in terms of feeding in the early morning but do tend to fly up and down rivers to feed throughout the day too. Works under the bridge could affect Kingfishers passage along the river channel through the bridge if large sections were to be closed off for the works.
Indirect water quality impacts could potentially affect fish populations in the river also which are a food source for this species. Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood. This would have a severe impact on fish populations which are a food source for Kingfisher.
5.3 Boyne Coast and Estuary SAC
The qualifying interests of the Boyne Coast and Estuary SAC are presented in Table 8 with the potential impacts of the proposed bridge rehabilitation works on each and the relevant type of mitigation measures required identified too. The qualifying interests are discussed individually below in terms of the potential impacts that could arise from the proposed works.
Table 7 Potential impacts on qualifying interests of the Boyne Coast and Estuary SAC that have the potential to be affected by the proposed works at Obelisk Bridge, with the type of mitigation measures required. Natura Qualifying interests Impacts Code 1130 Estuaries None of these habitats are present 1140 Tidal mudflats and sandflats at the proposed works site. They are do however occur from approximately 7.5rkm downstream 1210 Annual vegetation of drift lines of the subject bridge out eastwards
1310 Salicornia mud along the estuary to the coast. 1330 Atlantic salt meadows Therefore there is a hydrological 2110 Embryonic shifting dunes Habitats pathway for affects; there is 2120 Shifting dunes along the shoreline with potential for invasive species and Ammophila arenaria (White dunes) water quality impacts.
Annex I I Annex 2130 Marram dunes (Grey dunes)*
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5.3.1 Annex I Habitats
5.3.1.1 Estuaries (1130)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
This section of the River Boyne where the proposed works area is located is freshwater-tidal but the estuarine part of the watercourse may be affected by indirect water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality of the River Boyne and the Boyne's estuary habitat.
5.3.1.2 Tidal mudflats and sandflats (1140)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated mudflats and sandflats habitat.
5.3.1.3 Annual vegetation of drift lines (1210)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation
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will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated annual vegetation of drift lines habitat.
5.3.1.4 Salicornia mud (1310)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated Salicornia mud habitat.
5.3.1.5 Atlantic salt meadows (1330)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated Atlantic salt meadows habitat.
5.3.1.6 Embryonic shifting dunes (2110)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
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Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated Embryonic shifting dunes habitat.
5.3.1.7 Shifting dunes along the shoreline with Ammophila arenaria (White dunes) (2120)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated white dunes habitat.
5.3.1.8 Marram dunes (Grey dunes) (2130)
Depending on the precise procedures involved (which should be detailed in a Method Statement for the proposed works) there is likely to be a risk of water quality impacts associated with the proposed works. These can arise from an increase in suspended solids in the watercourse which can be generated by the activities at the works site and from accidental spillages of oil / fuel / paint and / or cement / concrete that may be used for the bridge rehabilitation works or residue / debris from blast cleaning of the bridge surface. Dewatering of areas is sometimes required for bridge rehabilitation works (this will be detailed in the Method Statement if required). In such situations there is also a risk of water quality impacts arising from the potential accidental release of sand into the river from sand bags used around dewatered areas in the event of a flood.
Although this habitat does not occur at the site of the proposed bridge works there is potential for the downstream habitat to be affected by water quality impacts from the proposed bridge works. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated grey dunes habitat.
5.4 Boyne Estuary SPA
The qualifying interests of the Boyne Estuary SAC are presented in Table 9 with the potential impacts of the proposed bridge rehabilitation works on each and the relevant type of mitigation measures required identified too. The qualifying interests are discussed individually below in terms of the potential impacts that could arise from the proposed works.
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Table 8 Potential impacts on qualifying interests of the Boyne Estuary SPA that have the potential to be affected by the proposed works at Obelisk Bridge. Natura Qualifying interests Impacts Code A999 Wetland and Waterbirds No designated Wetland and Waterbird habitat present at the proposed works site. There is a pathway for affects on designated Wetland and Waterbird habitat as it occurs over 6.5rkm downstream, to the east of
Drogheda so it is hydrologically connected to the proposed works site. Therefore, there is potential for invasive species and water quality impacts on this
Habitats habitat. A048 Shelduck Tadorna tadorna The bird species of interest for this designated site. The proposed works site is not important for this species however it occurs in the downstream estuary; there is potential for indirect impacts. A130 Oystercatcher Haematopus ostrale This species favours intertidal areas for foraging, which is available downstream in the estuary to the east of Drogheda but not at the subject bridge site. The main area for this species is located over 6.5rkm downstream of the subject bridge in the designated estuary area. There is potential for indirect impacts due to hydrological connection to the estuary where this species occurs. A140 Golden Plover Pluvialis apricaria This species may occur at the proposed works area, however it is considered that there is more suitable habitat downstream on the designated estuary. This species tends to aggregate in large groups along the estuary. Large numbers have been recorded in the estuary more than 9rkm downstream of the subject bridge (NPWS, 2012a). If this species does happen to be present at the time of the proposed works there is potential for some disturbance to the species. It is considered unlikely however, for this situation to arise or to have a significant impact on the species due to the availability of more favourable habitat where this species tends to occur downstream; and to which the species can migrate to in such a scenario. There is potential for indirect impacts due to hydrological connection to the estuary and coast. A141 Grey Plover Pluvialis squatarola This is a coastal species and is therefore not likely to occur at the proposed works area. The subject bridge site is not of significant importance for this species which tends to occur along the coast, approximately 12rkm downstream of the bridge. There is potential for indirect impacts due to hydrological connection to the estuary and coast. A142 Lapwing Vanellus vanellus It is possible for this species to occur at the subject bridge site as it can occur on inland wetland areas. If the species is present at the time of the
Species proposed works there is potential for some
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Natura Qualifying interests Impacts Code disturbance to the species. It is considered unlikely however for this situation to arise due to the availability of more favourable habitat where this species tends to occur, over 6.5rkm downstream of the subject bridge; and to which the species can migrate to in such a scenario. There is also potential for indirect impacts due to hydrological connection to the downstream estuary where this species is more likely to occur. A143 Knot Calidris canutus This is a coastal species and the subject bridge site is not considered to be of importance to this species. The main area for this species is located at the coastal end of the estuary where there more suitable habitat available. This species mainly occurs in the estuary from about 10rkm downstream of the subject bridge out eastwards to the coast. There is potential for indirect impacts due to hydrological connection to the estuary and coast. A144 Sanderling Calidris alba This is a coastal species and the subject bridge site is not considered to be of importance to this species. The species favours the sandy shoreline along the coast approximately 12rkm downstream of the subject bridge. There is some potential for indirect impacts due to hydrological connection to the estuary and coast. A156 Black-tailed Godwit Limosa limosa This species may occur at the subject bridge site as it can occur inland on grassland and river deltas. If the species is present at the time of the proposed works there is potential for some disturbance to the species. It is considered unlikely however for this situation to arise due to the availability of more favourable habitat where this species tends to occur, over 6.5rkm downstream of the subject bridge; and to which the species can migrate to in such a scenario. There is also potential for indirect impacts due to hydrological connection to the downstream estuary where this species is more likely to occur. A162 Redshank Tringa totanus This species relies on intertidal areas for foraging, which is available downstream in the estuary to the east of Drogheda but not at the subject bridge site. The main area for this species is located over 6.5rkm downstream of the subject bridge. There is potential for indirect impacts due to hydrological connection to the estuary where this species occurs.
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Natura Qualifying interests Impacts Code A169 Turnstone Arenaria interpres This is a coastal species and the subject bridge site is not considered to be of importance to this species. The main area for this species is located at the coastal end of the estuary where there are suitable rocky shorelines for foraging. This species is mainly found from about 10rkm downstream of the subject bridge out eastwards to the coast. There is potential for indirect impacts due to hydrological connection to the estuary and coast. A195 Little Tern Sterna albifrons This is a strictly coastal species and unlikely to occur at the proposed works area. There is some potential for indirect impacts as there is hydrological connection to the coast where this species occurs approximately 12rkm downstream of the subject bridge.
5.4.1 Habitats
5.4.1.1 Wetland and Waterbirds (A999)
The main wetland habitat that is of importance to waterbirds in the Boyne Estuary is located to the east of Drogheda and out along the estuary to the coast. Along these shores suitable foraging and roosting areas for waterbirds are found and support significant numbers of several species of waterbird. There is no designated wetland and waterbirds habitat at Obelisk Bridge, however, it is likely for the birds that occur in the SPA to be found around this subject bridge site on occasion too, particularly in bad weather for example, when they are likely to migrate further inland.
There is potential for the designated Wetland and Waterbird area, just over 6.5rkm downstream of the subject bridge site, to be affected by water quality impacts from the proposed bridge rehabilitation works (as described in section 5.1.1.1). Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and the associated wetland and waterbirds habitat.
5.4.2 Species
5.4.2.1 Shelduck Tadorna tadorna (A048)
Shelduck is not considered likely to regularly occur at the subject bridge site due to the fact that there is more favourable habitat downstream of Drogheda nearer to the coast in the Boyne Estuary, which supports this species. Shelduck does occur in nationally important numbers downstream of Drogheda in the Boyne Estuary; it is possible for the proposed works to have indirect impacts. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. Impacts on water quality would affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
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5.4.2.2 Oystercatcher Haematopus ostralegus (A130)
This species is not considered likely to be present at the site of the proposed bridge works as it tends to occur on the intertidal areas along the estuary over 6.5rkm downstream of the subject bridge (NPWS, 2012a). Oystercatcher does occur in nationally important numbers downstream of Drogheda in the Boyne Estuary. It is possible for the proposed works to have indirect impacts on the estuary population due to hydrological connection. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary and coast.
5.4.2.3 Golden Plover Pluvialis apricaria (A140)
It is possible that Golden Plover occur in the general area of the subject bridge site on occasion but the designated SPA site downstream of Drogheda (over 6.5rkm downstream of the subject bridge) is of particular importance. This species is not considered likely to be present at the site of the proposed bridge works. The species occurs in nationally important numbers in the Boyne Estuary, mainly found aggregating on tidal flats more than 8rkm downstream of the subject bridge (NPWS, 2012a). It is possible for the proposed works to have indirect impacts on this species. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.4 Grey Plover Pluvialis squatarola (A141)
This species is not considered likely to be often present at the site of the proposed bridge works as it is a coastal species. Grey Plover is supported in nationally important numbers downstream of Drogheda in the Boyne Estuary. It is possible for the proposed works to have indirect impacts. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.5 Lapwing Vanellus vanellus (A142)
Although it is possible for this species to occur near the proposed works area, there is more suitable habitat downstream in the designated SPA of the Boyne Estuary (over 6.5rkm downstream of the subject bridge) where the species occurs predominantly on the intertidal areas along the estuary, downstream of Drogheda (NPWS, 2012a). The designated downstream area supports nationally important numbers of Lapwing. It is possible for the proposed works to have indirect impacts on the Boyne Estuary population. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. ______www.ecofact.ie 38
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The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.6 Knot Calidris canutus (A143)
This species is not considered likely to be often present at the site of the proposed bridge works. Knot is a coastal species and occurs in nationally important numbers downstream of Drogheda in the Boyne Estuary (NPWS, 2012a) which provides more suitable habitat for this species (over 6.5rkm downstream of the subject bridge). It is possible for the proposed works to have indirect impacts on the Knot population of the Boyne Estuary. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.7 Sanderling Calidris alba (A144)
This species is not considered likely to be present at the site of the proposed bridge works as it tends to occur along the sandy shorelines at the coast. Such suitable habitat is found approximately 12rkm downstream of the subject bridge site along the coast within the Boyne Estuary SPA (NPWS, 2012a). Sanderling occurs in nationally important numbers in the SPA. It is possible for the proposed works to have indirect impacts. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary and coastal area to be subject to some water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.8 Black-tailed Godwit Limosa limosa (A156)
This species may be found at the subject bridge site on occasion but it is mainly found on and around the intertidal areas in the Boyne Estuary, downstream of Drogheda, from approximately 6.5rkm downstream of the subject bridge out to along the estuary towards the coast (NPWS, 2012a). It is possible for the proposed works to have indirect impacts on Black-tailed Godwit. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is supported in nationally important numbers to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food sources along the estuary. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.9 Redshank Tringa totanus (A162)
This species is not considered likely to be present at the site of the proposed bridge works as it is generally found along the intertidal habitat further downstream in the estuary. Redshank occurs in nationally important numbers downstream of Drogheda in the Boyne Estuary SPA (6.5rkm downstream of the subject bridge). It is possible for the proposed works to have indirect impacts on the Redshank population of the estuary. As described in section 5.1.1.1, there is a risk of water quality impacts ______www.ecofact.ie 39
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associated with bridge rehabilitation works. There is potential for the downstream estuary where this species is more likely to occur to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.10 Turnstone Arenaria interpres (A169)
Turnstone is not considered likely to be present at the site of the proposed bridge works, as this coastal species favours rocky shorelines. Turnstone is supported in nationally important numbers in the suitable habitat in the Boyne Estuary SPA, and is mainly found at the coast near the Boyne River mouth (NPWS, 2012a). It is possible for the proposed works to have indirect impacts on this species. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is potential for the coastal and estuarine areas where this species occurs to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
5.4.2.11 Little Tern Sterna albifrons (A195)
This species is not considered likely to be present at the site of the proposed bridge works. This species does occur in nationally important numbers downstream of Drogheda in the Boyne Estuary SPA, but is a strictly coastal species and so is only found along the coast to the east of Drogheda and approximately 12rkm downstream of the subject bridge (NPWS, 2012a). Due to the hydrological connection to the coast it is possible for the proposed works to have indirect impacts. As described in section 5.1.1.1, there is a risk of water quality impacts associated with bridge rehabilitation works. There is therefore potential for the downstream estuary and coastal area at the mouth of the River Boyne to be affected by water quality impacts from the proposed bridge works. The water quality impacts may affect the general quality of the habitat that supports this species and the availability of its food source. Mitigation will be required during the works to protect the water quality in the downstream Boyne Estuary.
6. MITIGATION
Mitigation measures for the protection of the riparian and aquatic environment have been prepared for the protection of the conservation interests of the River Boyne and River Blackwater SAC, River Boyne and River Blackwater SPA, Boyne Coast and Estuary SAC and Boyne Estuary SPA. The proposed rehabilitation works to Obelisk Bridge have been identified as having the potential to cause direct disturbance and water quality impacts, indirect water quality impacts and non-native invasive species impacts as well as cumulative impacts on water quality due to existing background water quality pressures in the River Boyne due to upstream agricultural diffuse and septic tank and landfill pollution (ERBD, 2010).
The table below summarises the mitigation measures required for to prevent residual impacts on the qualifying interests of the affected Natura 2000 sites.
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Table 9 Potential impacts on qualifying interests of the affected Natura 2000 sites that have potential to be affected by the proposed works at Obelisk Bridge, with the required mitigation measures summarised and residual impacts identified.
Natura Qualifying Interest Natura Potential Impact Mitigation Measures Residual Impacts 2000 Code site Alkaline fens 7230 None None required. No residual impacts Alluvial forests with 91E0 Damage to Alluvial forest on Fence off a buffer area around the Alluvial No residual impacts Alnus glutinosa and downstream right bank within proposed forest to protect the habitat on the Fraxinus excelsior works area during works; general water downstream right side of the bridge. Avoid (Alno-Padion, Alnion quality impacts from sediment release accessing the bridge from this bank. Water incanae, Salicion and contaminated run-off; invasive quality protection measures to prevent albae)* species spread / introduction. contamination of the watercourse. Biosecurity measures to prevent introduction or spread of invasive species. A detailed site-specific CEMP and Method Statement will be prepared to ensure works are carried out to comply with mitigation and
best practice methods to prevent adverse impacts. Atlantic salmon 1106 Disturbance impacts on individuals Water quality protection measures to No residual impacts (Salmo salar) present at the subject bridge site; prevent contamination of the watercourse. general water quality impacts from Biosecurity measures to prevent sediment release and contaminated run- introduction or spread of invasive species. off; and invasive species spread / A detailed site-specific CEMP and Method introduction affecting habitat at the Statement will be prepared to ensure works subject bridge site. are carried out to comply with mitigation and best practice methods to prevent adverse impacts. River lamprey 1099 Disturbance impacts on individuals Water quality protection measures to No residual impacts (Lampetra fluviatilis) present at the subject bridge site, with prevent contamination of the watercourse. particular risk of harming larvae present Biosecurity measures to prevent in the substrate if entering watercourse; introduction or spread of invasive species. general water quality impacts from A detailed site-specific CEMP and Method
River Boyne and River Blackwater SAC (002299) SAC Blackwater River and Boyne River sediment release and contaminated run- Statement will be prepared to ensure works
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Natura Qualifying Interest Natura Potential Impact Mitigation Measures Residual Impacts 2000 Code site off; and invasive species spread / are carried out to comply with mitigation and introduction affecting habitat at the best practice methods to prevent adverse subject bridge site. impacts. Otter (Lutra lutra) 1355 Disturbance impacts on individuals Works limited to daylight hours to avoid No residual impacts using the subject bridge site; general disturbing / deterring otters which are active water quality impacts from sediment at night. Water quality protection measures release and contaminated run-off; and to prevent contamination of the invasive species spread / introduction watercourse. Biosecurity measures to affecting habitat at the subject bridge prevent introduction or spread of invasive site and potentially food availability, (in species. A detailed site-specific CEMP and particular Crayfish plague affecting Method Statement will be prepared to Crayfish population, an important prey ensure works are carried out to comply with for Otter). mitigation and best practice methods to prevent adverse impacts. Kingfisher Alcedo A229 Disturbance impacts on individuals Ensure at least partial access available for No residual impacts atthis passing through the subject bridge site; kingfishers to fly under bridge along general water quality impacts from watercourse. Water quality protection sediment release and contaminated run- measures to prevent contamination of the off, potentially affecting habitat quality watercourse. Biosecurity measures to and food availability; and invasive prevent introduction or spread of invasive species spread / introduction affecting species. A detailed site-specific CEMP and habitat in the vicinity of the subject Method Statement will be prepared to bridge site. ensure works are carried out to comply with mitigation and best practice methods to
River Boyne and River (004232) SPA Blackwater prevent adverse impacts. Estuaries 1130 There may be indirect impacts as these Water quality protection measures to No residual impacts Tidal mudflats and 1140 habitats do not occur at the subject prevent contamination of the watercourse. No residual impacts
sandflats bridge site but they do occur from Biosecurity measures to prevent Annual vegetation of 1210 approximately 7.5rkm downstream of introduction or spread of invasive species. No residual impacts drift lines the proposed works. There is A detailed site-specific CEMP and Method Salicornia mud 1310 No residual impacts hydrological connection to them. The Statement will be prepared to ensure works Boyne Coast and and Coast Boyne Estuary SAC (0091957) Atlantic salt meadows 1330 No residual impacts
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Natura Qualifying Interest Natura Potential Impact Mitigation Measures Residual Impacts 2000 Code site Embryonic shifting 2110 watercourse can carry sediment are carried out to comply with mitigation and No residual impacts dunes released from the proposed works and best practice methods to prevent adverse Shifting dunes along 2120 contaminated run-off as well as invasive impacts. No residual impacts the shoreline with species introduced to the site Ammophila arenaria (White dunes) downstream to these habitats and have Marram dunes (Grey 2130 adverse affects on the habitat quality. No residual impacts dunes)* Wetland and A999 Disturbance impacts will be localised at Water quality protection measures to No residual impacts Waterbirds the subject bridge site, some prevent contamination of the watercourse. Shelduck Tadorna A048 disturbance impacts may occur for Biosecurity measures to prevent No residual impacts tadorna individuals that may occasional be found introduction or spread of invasive species. Oystercatcher A130 No residual impacts Haematopus at the subject bridge site in the A detailed site-specific CEMP and Method ostralegus freshwater-tidal reaches of the river. Statement will be prepared to ensure works Golden Plover A140 However, the impacts on this SPA's are carried out to comply with mitigation and No residual impacts Pluvialis apricaria qualifying interests are mainly indirect. best practice methods to prevent adverse Grey Plover Pluvialis A141 There is hydrological connection to the impacts. No residual impacts squatarola main waterbird habitat of the estuary. Lapwing Vanellus A142 No residual impacts vanellus The watercourse can carry sediment Knot Calidris canutus A143 released from the proposed works and No residual impacts Sanderling Calidris A144 contaminated run-off as well as invasive No residual impacts alba species introduced to the site Black-tailed Godwit A156 downstream to these habitats and have No residual impacts Limosa limosa adverse affects on the habitat quality. Redshank Tringa A162 No residual impacts totanus Turnstone Arenaria A169 No residual impacts interpres Little Tern Sterna A195 No residual impacts Boyne Estuary SPA (004080) SPA Estuary Boyne albifrons
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6.1 Detailed Method Statement and CEMP
The main mitigation measure to be taken is that a prior to commencement of works a site specific Construction and Environmental Management Plan and Method Statement must be drawn up detailing precisely how the works will be carried out in compliance with the necessary mitigation measures. These documents will provide the precise details of the works to be undertaken and how each process and each step of the works will be carried out to adhere to the mitigation measures: timing of works, limiting access outside of the proposed works area, biosecurity protocols and water quality protection measures. The CEMP and Method Statement will be prepared following best practice procedure and guidelines, having due regard to the relevant sections of the following:
• IFI, (2010) 'Biosecurity Protocol for Field Survey Work' • IFI, (2016) 'Guidelines of protection of Fisheries during construction works in and adjacent to waters' • NRA, (2010) 'The Management of Noxious Weeds and Non-Native Invasive Plant Species on National Roads' • NRA, (2008) 'Guidelines for the Crossing of Watercourses During the Construction of National Road Schemes' • CIRIA (2006) 'Control of Water Pollution from Linear Construction Projects- Site Guide (C649)' • CIRIA (2005) 'Environmental Good Practice – Site Guide (C650)'
6.2 Avoidance
6.2.1 Footprint of works
The footprint of the works will be limited and works areas will be surrounded by silt fences and sand bags to help prevent water contamination from the proposed bridge works. Appropriate set back distances from sensitive ecological sites such as Alluvial forest areas and the River Boyne will be maintained. The main site compound will not be located within 10 m of the river and will be located on dry land.
Access to the river for any instream bridge works should be limited to a single access route to minimise the footprint of works. Impacts to the riparian habitats will be kept to a minimum with natural re- vegetation after the completion of works. The access point must avoid the protected Alluvial forest which is present on the downstream side of the bridge on the south bank of the river. A buffer area around the Alluvial forest that occurs at the subject bridge site will be fenced off to prevent accidental damage.
Although no suitable nesting habitat for Kingfishers was noted in the vicinity of the bridge during the current surveys, this species is also considered likely to use this stretch of river for foraging. Free access under at least a portion of the bridge must be provided at all times to allow safe passage along the river channel for wildlife such as Kingfisher and Otter.
6.2.2 Timing of works
The proposed works should also take place outside of lamprey spawning season which takes place from May to July. Works should also be limited to daylight hours to avoid potential disturbance to nocturnal animals foraging at the subject bridge site, namely Otter. Works should be limited to between 8am and 5pm.
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6.3 Water Quality Protection
Any oiling or refuelling of machinery that may be required will be undertaken away from the River Boyne. Any oils or fuels that may be required for minor machinery used during the proposed works will be stored appropriately in bunded tanks in the site compound (which should be fenced off 10m from the river) to ensure no spillages occur. Machinery will be well-maintained and checked for leaks prior to its use on site and prior to working in-stream if required. Spill kits will be used and any leaks on site will be cleaned immediately. The site compound will have security to deter vandalism, theft and unauthorised access.
Any tool washing and waste / grey water from the site will be stored securely until it can be removed from site. Contained chemical portaloo toilets will be used and all sewage appropriately removed from the site to an authorised treatment plant.
Silt fences will be placed on the outside of the works area first, with sand bags placed inside to ensure no impacts regarding suspended solids arise. Details of the sandbags, if required, will be included in the method statement. The site ecologist will ensure that any sand bags and silt fences are erected correctly, if required. Encapsulation of scaffolding will be securely put in place to catch any residue from blast cleaning of the bridge surface.
The works area will be fenced to avoid trampling or disturbance by personnel outside of the works area or by public access to the site.
Works should be sectioned so works will not take place across the entire river channel at once. When the works on one section is complete the works area will be removed appropriately and the normal flow returned before the works area for the next section is assembled. This will allow flow to be diverted easily and will ensure that any risk posed by a potential flood event will be reduced, as fewer sandbags will need to be removed, and there will be less risk in relation to release of silt into the River Boyne.
The site ecologist will over-see the set-up of dry works areas if any are required for the proposed works. Any lamprey and fish species potentially caught behind the dammed area will be translocated upstream by the ecologist who will have obtained a section 14 license for this activity.
No concrete / cement mixing will be carried out at the river bank area; mixing within the mixing area in the site compound will be controlled by the contractor, with all wash water, tool washings and any waste / grey water stored securely and removed; no waste will be stored on site; concrete / cement and grout work must be carried out behind the silt fencing and sandbags, in the dry works area. Storage areas for concrete / cement and grout required for the works will be included in the site compound. The waste from any vegetation removal will also have to be dealt with appropriately away from the River Boyne.
If there is a requirement for pumping out water from the dammed works area silt bags will be installed at the end of the pumping pipes to filter water to be pumped from the dammed section of the river. These silt bags will be specified in the detailed method statement to adequately cope with the volume of water and will be maintained so it is operating effectively with suspended solids loadings at the end of pipe at less than 10 mg/l. Any dewatering, passing through a silt bag would be similar in nature to flood water in the area.
6.4 Biosecurity
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No invasive species were recorded at the site during the site survey but precautions will be taken to ensure that no invasive species are introduced due to the proposed works. Biosecurity measures will follow NRA guidelines ‘The Management of Noxious Weeds and Non-native Invasive Plant Species on National Roads’ (NRA, 2010) and the IFI guidelines ‘Biosecurity Protocol for Field Survey Work’ (IFI, 2010).
Small numbers of White-clawed Crayfish occur in the Boyne system. Crayfish is a key food source for Otter and the spread of crayfish plague as a result of the proposed bridge works could have significant impacts on Crayfish and indirectly on Otters in the Boyne. Also, crayfish plague has affected crayfish in the Boyne in the past and if it was present at the subject bridge site, the machinery / equipment used could transfer the disease to other watercourses too. Particular attention will have to be given to sterilising all equipment / work gear that will come in contact with the river, by using suitable disinfectants such as Virkon aquatic, to ensure no spread of crayfish plague occurs. All equipment to be used on site will be steam cleaned before dispatching to site, and all hired equipment will be treated on site with an approved biocide / cleaning agent. A disinfection / cleaning station will be set up next to the site compound and 10 m back from the river.
6.5 Site Ecologist
A site ecologist will need to be appointed for the duration of the proposed works. The site ecologist will work with the contractor to draw up the precise site-specific method statement prior to the commencement of works. This method statement will include precise details of the works, accessing areas, equipment / machinery / materials etc. for each stage of the project. This will ensure that the works are carried out following the best practice guidelines and the mitigation measures provided in this document with minimal impacts on the Natura 2000 network. The ecologist will be on site on a regular basis to ensure compliance with the environmental and ecological protection measures specified in the method statement.
A site induction will be carried out by the site ecologist for all contractors' personnel including sub- contractor staff attending the site. The site induction will ensure that any person working on site is aware of the mitigation measures that will be implemented on site. This will include limiting access to within the works area, timing of works, water quality protection measures and biosecurity protocols. This will be the first element of the works undertaken.
7. IMPLICATIONS FOR CONSERVATION OBJECTIVES
Favourable conservation status is defined for Annex I habitats and Annex II species in the Habitat Directive (1992):
Article 1 (e) Conservation status of a natural habitat means the sum of the influences acting on a natural habitat and its typical species that may affect its long-term natural distribution, structure and functions as well as the long-term survival of its typical species within the territory referred to in Article 2. The conservative status of a natural habitat will be taken as 'favourable' when: its natural range and areas it covers within that range are stable or increasing, and the specific structure and functions which are necessary for its long-term maintenance exist and are likely to continue to exist for the foreseeable future.
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Conservation status of a species means the sum of the influences acting on the species concerned that may affect the long-term distribution and abundance of its populations within the territory referred to in Article 2; The conservation status will be taken as 'favourable' when: population dynamics data on the species concerned indicate that it is maintaining itself on a long-term basis as a viable component of its natural habitats, and the natural range of the species is neither being reduced nor is likely to be reduced for the foreseeable future, and there is, and will probably continue to be, a sufficiently large habitat to maintain its populations on a long-term basis.
7.1 Conservation Objectives for the affected Natura 2000 sites
The Conservation Objectives for the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and Boyne Estuary SPA have been prepared by the National Parks and Wildlife Service (NPWS) of the Department of Arts, Heritage and the Gaeltacht (NPWS, 2020a; NPWS 2020b; NPWS 2012; NPWS, 2013). The overall aim of the Habitats Directive is to maintain or restore the favourable conservation status of habitats and species of community interest. These habitats and species are listed in the Habitats and Birds Directives and SACs and SPAs are designated to afford protection to the most vulnerable of them. These two designations are collectively known as the Natura 2000 network. European and national legislation places a collective obligation on Ireland and its citizens to maintain habitats and species in the Natura 2000 network at favourable conservation condition. The Government and its agencies are responsible for the implementation and enforcement of regulations that will ensure the ecological integrity of these sites.
Site-specific conservation objectives aim to define favourable conservation condition for a particular habitat or species at that site. The maintenance of habitats and species within Natura 2000 sites at favourable conservation condition will contribute to the overall maintenance of favourable conservation status of those habitats and species at a national level. Favourable conservation status of a habitat is achieved when: • its natural range, and area it covers within that range, are stable or increasing, and • the specific structure and functions which are necessary for its long-term maintenance exist and are likely to continue to exist for the foreseeable future, and • the conservation status of its typical species is favourable.
The favourable conservation status of a species is achieved when: • population dynamics data on the species concerned indicate that it is maintaining itself on a long-term basis as a viable component of its natural habitats, and • the natural range of the species is neither being reduced nor is likely to be reduced for the foreseeable future, and • there is, and will probably continue to be, a sufficiently large habitat to maintain its populations on a long-term basis
In the documents outlining the conservation objectives for the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and Boyne Estuary SPA (NPWS, 2020a; NPWS 2020b; NPWS 2012; NPWS, 2013), each conservation interest is discussed separately as a conservation objective. Attributes and targets given in these conservation objectives were based on best available information at the time of writing.
The proposed rehabilitation works at Obelisk Bridge on the River Boyne have been identified as having the potential for water quality impacts with regard to possible in-stream works and the potential requirement of cement / concrete and paint for the works on the bridge. The implementation of the ______www.ecofact.ie 47
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mitigation measures prescribed for the works will result in these impacts being reduced to imperceptible in scale.
There are no impacts arising from the proposed works which would have the potential to affect the conservation status of the habitats or species listed as qualifying interests of the affected Natura sites. The proposed works will not affect the conservation objectives of these sites or have an adverse effect on the requirements to meet the conservation objectives with regard to the restoration if habitats and species to favourable conservation status. Water quality is identified as a key sensitivity of the water- dependent qualifying interests of these designated sites. Measures to protect water quality to avoid impacts affecting the aquatic species of the designated sites have been included in the mitigations section of the current report.
The provisions of Article 6 of the ‘Habitats’ Directive 92/43/EC (2000) defines ‘integrity’ as the: ‘coherence of the site’s ecological structure and function, across its whole area, or the habitats, complex of habitats and/or population of species for which the site is or will be classified’.
With regard to the integrity of the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and Boyne Estuary SPA, these sites are affected by a history of impacts on water quality and heavy watercourse modification, which has direct impacts on the conservation interests of the associated Natura 2000 sites. The proposed works are limited in scale and will comply with the required mitigations to ensure that there will be no further impacts arising which would affect the coherence of the SACs and SPAs ecological structure and function; particularly with regard to the Annex II populations recorded from within the study area. The proposed works are not identified as having the potential to adversely affect the conservation objectives of the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and Boyne Estuary SPA or with the integrity of the Natura 2000 sites affected, provided mitigation measures are followed.
8. CONCLUSION STATEMENT
The current NIS has been undertaken to evaluate the potential impacts of the proposed bridge rehabilitation works with regard to the effects upon the conservation objectives and qualifying interests (including habitats and species) of the River Boyne and River Blackwater SAC (Site Code: 002299), the River Boyne and River Blackwater SPA (Site Code: 004232), the Boyne Coast and Estuary SAC (Site Code: 0091957) and the Boyne Estuary SPA (Site Code: 004080). The proposed rehabilitation works at Obelisk Bridge in Co. Louth are located within the River Boyne and River Blackwater SAC and the River Blackwater SPA; the subject bridge site is also hydrologically connected with the Boyne Coast and Estuary SAC and the Boyne Estuary SPA, which are located downstream within 10km of the Obelisk Bridge. In cases where mitigation measures are required to reduce or avoid a significant adverse effect on Natura 2000 sites, then Appropriate Assessment (Natura Impact Statement) is required. It has been identified that there is potential for impacts from the proposed works to impact on these Natura 2000 sites and mitigation for the proposed works is required as set out in the current document.
The works required are expected to involve instream and out-of-stream works and include masonry, pavement and steelwork repairs as well as repainting and some vegetation removal. As with any works of this nature, water quality impacts can arise from an increase in suspended solids in the watercourse and accidental spillages of oil / fuel and / or cement / concrete / paint. There is also a risk of disturbance to ecology in the immediate vicinity of the bridge and there is the possibility of invasive species introduction to the proposed works area via machinery or equipment which may spread and affect the
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Obelisk Bridge, Co. Louth – Rehabilitation Works Natura Impact Statement______nearby Natura 2000 sites. Taking cognisance of the sensitivity of the water-dependent species and the habitats listed as qualifying interests of the afore-mentioned Natura 2000 sites, mitigations must be implemented at the subject bridge site during the proposed rehabilitation works.
The main mitigation is that a site-specific Construction and Environmental Management Plan (CEMP) and a detailed method statement are required to be drawn up for the works. This CEMP and method statement will incorporate the specifics of the mitigation provided in this document which is necessary to protect the qualifying interests of the local Natura 2000 sites. These documents will outline clearly and precisely how the each step of the proposed works will be undertaken in compliance with mitigation to protect the Natura 2000 sites. In particular, strict water quality protection measures will be implemented throughout the project to mitigate impacts on all aquatic Annex II species in the affected area, including Atlantic salmon, Otter and River lamprey and the Annex I habitat, Alluvial forest which occurs in the vicinity of the works as well as the other downstream water dependant features of interest in the Boyne Coast and Estuary SAC and the Boyne Estuary SPA. These measures include: on-site refuelling in areas setback from any watercourse or drain; encapsulation of scaffolding during blast cleaning; use of silt fencing; the use of spill kits; any leaks will be cleaned up immediately; equipment and machinery will be regularly maintained and if repairs are not possible, will be removed from site; no concrete / cement mixing will be carried out adjacent to any watercourse or drain; any tool washing and any waste / grey water will be stored securely behind bunded areas until its removal from the site; contained chemical portaloos toilets will be used and all sewage will be appropriately removed from the site to an authorised treatment plant. Routine monitoring will be carried out to ensure compliance with measures throughout the works.
The proposed works are not considered to have significant impacts once mitigation measures are appropriately implemented and followed. However, it is noted again that a detailed method statement is required for the proposed works which will detail the specific procedures of the rehabilitation works, including details of any instream works and dewatering of areas that may be required. The method statement and CEMP will need to include precise details of mitigation measures such as set-back distances, types of sandbags and silt fencing used, the location of fuelling and storage areas, access route etc. to ensure that the mitigation is appropriately incorporated and adhered to.
The provisions of Article 6 of the ‘Habitats’ Directive 92/43/EC (2000) defines ‘integrity’ as the ‘coherence of the site’s ecological structure and function, across its whole area, or the habitats, complex of habitats and / or population of species for which the site is or will be classified’. The mitigation measures proposed are considered to be sufficient to ensure that potential impacts regarding disturbance, water quality and invasive species are avoided / minimised. From the evidence presented in the current assessment, it is concluded that the potential direct, indirect and cumulative impacts that may arise from the proposed works do not have the potential to affect the integrity of the River Boyne and River Blackwater SAC, the River Boyne and River Blackwater SPA, the Boyne Coast and Estuary SAC and Boyne Estuary SPA.
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9. Other Ecological Interests
The current document is an NIS and Ecofact were not commissioned to carry out an assessment of other ecological interests that may be covered an EcIA report. This section briefly deals with issues which are not addressed in an Appropriate Assessment Natura Impact Statement.
9.1 Bats
It is noted that all bat species are strictly protected under Annex V of the EU Habitats Directive (European Protected Species). A bat suitability deskstudy was carried for the proposed works location at Obelisk Bridge (Table 1). The site survey of the bridge also included a brief assessment of roosting potential of the bridge structure for bats.
It was determined that there is limited bat potential at Obelisk Bridge and bats are unlikely to be present in the structure. None-the-less it is possible for an individual or small number of bats to use the bridge on occasion and for that reason it is recommended that a pre-works screening be undertaken to confirm this before the works commence.
The National Biodiversity Data Centre (NBDC) maps landscape suitability for bats based on Lundy et al., (2011). The maps are a visualisation of the results of the analyses based on a 'habitat suitability' index. The index ranges from 0 to 100, with 0 being least favourable and 100 most favourable for bats. Table 1 below gives the suitability of the study area for the bat species found in Ireland (based on NBDC) along with their Irish Red List Status (from Marnell et al., 2009). The overall assessment of bat habitats for the current study area is given as 33.89.
Table 10 Suitability of the study area for the bat species previously recorded in the Obelisk Bridge area based on the NBDC data. Irish Red list status also indicated (based on Marnell et al., 2009). Common name Scientific name Suitability index Irish red list status All bats - 33.89 Soprano pipistrelle Pipistrellus pygmaeus 44 Least Concern Brown long-eared bat Plecotus auritus 39 Least Concern Common pipistrelle Pipistrellus pipistrellus 47 Least Concern Lesser horseshoe bat Rhinolophus hipposideros 0 Least Concern Leisler’s bat Nyctalus leisleri 47 Near Threatened Whiskered bat Myotis mystacinus 36 Least Concern Daubenton's bat Myotis daubentonii 37 Least Concern Nathusiius's pipistrelle Pipistrellus nauthusii 13 Least Concern Natterer’s bat Myotis nattererii 42 Least Concern
9.2 Crayfish
The Boyne catchment was subject to a crayfish plague outbreak in 1987. Almost the entire White-claw Crayfish population of the Boyne was wiped out by the disease. Crayfish now occur in small numbers in parts of the Boyne (Reynolds and O'Keeffe, https://www.npws.ie/sites/default/files/publications/pdf/Crayfish_leaflet.pdf). Crayfish are an important part of an Otter’s diet. Impacts on the Crayfish population of the Boyne would therefore also impact on the Otter population in the river system, a species of interest of the River Boyne and River Blackwater SAC. Biosecurity measures must be taken with the proposed bridge works in order to prevent the spread of crayfish plague which can easily be transferred on equipment or machinery that may come in contact with it during the proposed bridge works. Biosecurity mitigation measures are provided in section 6.4 of the current document.
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REFERENCES
Atkins (2013). Obelisk Bridge (ID: LH-LP2321-001.00) – Inventory and Principal Inspection Report.
CIRIA, (2002). Control of Water Pollution on Construction Sites- Guide to Good Practice (SP156). 6 Storey's Gate, Westminster, London.
CIRIA, (2001). Control of Water Pollution from Construction sites- Guidance for Consultants and Contractors (C532). 6 Storey's Gate, Westminster, London.
CIRIA, (2006). Control of Water Pollution from Linear Construction Projects -Technical Guidance (C649). 6 Storey's Gate, Westminster, London.
CIRIA, (2006). Control of Water Pollution from Linear Construction Projects- Site Guide (C649). 6 Storey's Gate, Westminster, London.
CIRIA, (2005). Environmental Good Practice – Site Guide (C650). 6 Storey's Gate, Westminster, London.
Cummins, S.; Fisher, J.; Gaj McKeever, R.; McNaghten, L.; Crowe, O., (2010). Assessment of the distribution and abundance of Kingfisher Alcedo atthis and other riparian birds of six SAC river systems in Ireland. https://www.npws.ie/sites/default/files/publications/pdf/Cummins_et_al_2010_Kingfisher_survey.pdf
DoEHLG, (2010) ‘Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities’. National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government, Dublin.
EPA (2018). Boyne Catchment Assessment 2010-2015. https://www.catchments.ie/wp- content/files/catchmentassessments/07%20Boyne%20Catchment%20Summary%20WFD%20Cycle% 202.pdf
Fitzmaurice, P. (1981) The spread of roach (Rutilus rutilus L.) in Irish waters. waters. In Proceedings of the Second British Freshwater Fisheries Conference. Liverpool, University of Liverpool, 154/61. Harvey J & Cowx I (2003). Monitoring the River, Brook and Sea Lamprey, Lampetra fluviatilis, L. planeri and Petromyzon marinus. Conserving Natura 2000 Rivers Monitoring Series No. 5, English Nature, Peterborough.
Gillings, S., Austin, G. E., Fuller, R. J., & Sutherland, W. J. (2006) Distribution shifts in wintering Golden Plover Pluvialis apricaria and Lapwing Vanellus vanellus in Britain. Bird Study 53, 274-284. IFI, (2010). IFI Biosecurity Protocol for Field Survey Work. Inland Fisheries Ireland, Swords Business Campus, Swords, Co. Dublin, Ireland.
IFI, (2016). Guidelines on Protection of Fisheries During Construction Works in and Adjacent to Waters. Inland Fisheries Ireland, Swords Business Campus, Swords, Co. Dublin, Ireland.
Lundy, MG, Aughney T, Montgomery WI, Roche N (2011) Landscape conservation for Irish bats & species specific roosting characteristics. Bat Conservation Ireland.
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http://www.batconservationireland.org/wp- content/uploads/2013/09/Landscape_Conservation_Irish_Bats.pdf
Maitland PS (2003). Ecology of the River, Brook and Sea Lamprey. Conserving Natura 2000 Rivers. Ecology Series No. 5. English Nature, Peterborough.
Marnell, F., Kingston, N. & Looney, D. (2009) Ireland Red List No.3: Terrestrial Mammals, National Parks and Wildlife Service, Department of the Environment, Heritage and Local Government, Dublin, Ireland. https://www.npws.ie/sites/default/files/publications/pdf/RL3.pdf
NPWS (2011) Boyne Coast & Estuary SAC (site code 1957) – conservation objectives supporting document – marine habitats and species. Version 1. December 2011.
NPWS (2012a). Boyne Estuary SPA Conservation Objectives Supporting Document. https://www.npws.ie/sites/default/files/publications/pdf/004080_Boyne%20Estuary%20SPA%20Suppo rting%20Doc_V1.pdf
NPWS (2012b). Boyne Coast and Estuary SAC – Conservation objectives supporting document – coastal habitats. https://www.npws.ie/sites/default/files/publications/pdf/001957_Boyne%20Coast%20and%20Estuary %20SAC%20Coastal%20Supporting%20Doc_V1.pdf
NPWS (2012c). Boyne Coast and Estuary SAC – Conservation objectives supporting document – marine habitats. https://www.npws.ie/sites/default/files/publications/pdf/001957_Boyne%20Coast%20and%20Estuary %20SAC%20Marine%20Supporting%20Doc_V1.pdf
NPWS (2012) Conservation Objectives: Boyne Coast and Estuary SAC 001957. Version 1.0. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht. https://www.npws.ie/sites/default/files/protected-sites/conservation_objectives/CO001957.pdf
NPWS (2013) Conservation Objectives: Boyne Estuary SPA 004080. Version 1. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht. https://www.npws.ie/sites/default/files/protected-sites/conservation_objectives/CO004080.pdf
NPWS (2020a) Conservation objectives for River Boyne and River Blackwater SAC [002299]. Generic Version 7.0. Department of Culture, Heritage and the Gaeltacht. https://www.npws.ie/sites/default/files/protected-sites/conservation_objectives/CO002299.pdf
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O’Connor W. (2006) A survey of juvenile lamprey populations in the Boyne Catchment. Irish Wildlife Manuals, No. 24 National Parks and Wildlife Service, Department of Environment, Heritage and Local Government, Dublin, Ireland. OʹGrady, M.F. (1998) Rehabilitation of the Boyne. Institution of Engineers of Ireland Journal March Issue, pp. 22‐24.
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PLATES
Plate 1 Obelisk Bridge is a narrow Road Bridge over the main channel of the River Boyne upstream of Drogheda Town.
Plate 2 The River Boyne at Obelisk Bridge is a 6th order channel and is freshwater-tidal. This site is within both the River Boyne and River Blackwater SAC and the River Boyne and River Blackwater SPA.
Plate 3 Alluvial forest habitat is present on the banks of the River Boyne at Obelisk Bridge. This a priority habitat of qualifying interest for the River Boyne and River Blackwater SAC.
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Plate 4 A rocky outcrop was present on the bank of the River Boyne beside Obelisk Bridge.
Plate 5 Thick vegetation over growth is present on Boyne river banks around Obelisk Bridge with some growth on the structure itself. Vegetation removal will be involved in the bridge rehabilitation works.
Plate 6 A canal of the Boyne navigation runs parallel to the main River Boyne at this section of the River Boyne at Obelisk Bridge.
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Plate 7 Algae was present near the end of the Old Bridge Boyne Canal which connects to the main Boyne near Obelisk Bridge.
Plate 8 There are nature walking routes along the Boyne and its tributaries in the locality of Obelisk Bridge.
Plate 9 A nearby small tributary of the Boyne was almost completely dry at the time of the current surveying at Obelisk Bridge.
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APPENDIX 1 Screening for Appropriate Assessment Matrix
Although Ecofact were not engaged to undertake a screening for Appropriate Assessment for the proposed bridge rehabilitation works, this matrix briefly outlines the Natura 2000 sites considered for the preparation of the current NIS.
Brief Description The proposed project relates to remediation works on Obelisk Bridge in County Louth. of the Project or The bridge is located in the Drogheda Town crossing over the main channel of the River Plan Boyne. The work that is required is likely to involve both in-stream and out-of-stream works. Brief Description River Boyne and River Blackwater SPA (Site Code: 004232): of the Natura 2000 This site comprises a long linear stretch along the River Boyne and several of its Sites within 15km tributaries, including the river channel and marginal vegetation. Most of the site is in County Meath but it also extends into counties Cavan, Louth and Westmeath. The site includes the section of the Boyne from the M1 motorway bridge, west of Drogheda, to the junction with the Royal Canal, west of Longwood, Co. Meath as well as sections on the Blackwater, Tremblestown, Athboy, Stoneyford and Deel Rivers also. This site is of special conservation interest for Kingfisher which is listed on Annex I of the EU Birds Directive. Included in the current Screening: Yes – Obelisk Bridge is located in this SPA, there is direct pathway for potential impacts.
River Boyne and River Blackwater SAC (Site Code: 002299): This site consists of the freshwater element of the River Boyne as far as the Boyen Aqueduct, the Blackwater as far as Lough Ramor and the Deel, Stoneyford and Tremblestown Rivers which are tributaries of the Boyne. This site is of special conservation interest for three aquatic species protected under Annex II of the EU Habitats Directive and two habitats protected under Annex I of the directive. One habitat; Alluvial forest, is a priority habitat. Included in the current Screening: Yes – Obelisk Bridge is located over the River Boyne, there is a direct pathway for potential impacts.
Boyne Coast and Estuary SAC (Site Code: 0091957): This site is a coastal site located to the east of Drogheda Town. The site includes most of the tidal sections of the River Boyne, intertidal sand- and mudflats, saltmarshes, marginal grassland, and the stretch of coast from Bettystown to Termonfeckin that includes the Mornington and Baltray sand dune systems. The site is of special conservation interest for eight habitats listed on Annex I of the EU Habitats Directive, one of which; Fixed dunes (Grey dunes) is a priority habitat. Included in the current Screening: Yes – Obelisk Bridge is located over the River Boyne c.7.5rkm upstream of this site, there is a pathway for potential impacts.
Boyne Estuary SPA (Site Code: 004080): This site is a moderately-sized coastal site situated on the border of Counties Meath and Louth and comprising most of the estuary of the River Boyne. The site is of special conservation interest for Wetland and Waterbirds with eleven bird species individually listed as qualifying interests of the site also. This estuary is the second most important estuary for wintering birds on the Louth-Meath coastline. Part of the Boyne Estuary SPA is a Wildfowl Sanctuary. Three species that regularly occur at this site are listed on Annex I of the EU Birds Directive. Included in the current Screening: Yes – Obelisk Bridge is located over the River Boyne c.6.5rkm upstream of this site, there is a pathway for potential impacts.
River Nanny Estuary and Shore SPA (Site Code: 004158): This site comprises the estuary of the River Nanny and sections of the shoreline to the north and south of the estuary in County Meath. The estuary extends inland for approximately 2km and the channel is narrow and well sheltered. The site is of special conservation interest for Wetland and Waterbirds with six bird species individually listed as qualifying interests of the site also. This site is mostly important for roosting areas but feeding habitats is also provides on the intertidal flats. There are two species listed on Annex I of the EU Birds Directive which regularly occur at this site. Included in the current Screening: No – this site is located c. 12.4km from Obelisk Bridge. There is no potential pathway for impacts on this SAC.
Clogher Head SAC (Site Code: 001459):
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This site is located approximately 10km north-east of Drogheda in County Louth. Clogher Head is a promontory of Silurian quartzite. The rocks are covered with a thin layer of soil that supports areas of coastal heath community. Areas of sea cliff, bedrock shore and dry grassland also occur within the site. The site is of special conservation interest for two habitats listed on Annex I of the EU Habitats Directive: Vegetated Sea Cliffs and Dry Heath. Included in the current Screening: No – this site is located c. 13.9km from Obelisk Bridge. There is no potential pathway for impacts on this SAC.
Potential Impacts Direct impacts may arise that could affect River Lamprey, Atlantic salmon and Otter. All that May Arise of these species are listed on Annex II of the EU Habitats Directive and are considered likely to be present at this bridge site. The priority Annex I habitat Alluvial forest is also present at the site and therefore could be directly impacted by the works. Kingfisher may also use this site and may be directly impacted.
These species / habitats as well as other habitats and species that are qualifying interests of the downstream Boyne Coast and Estuary SAC and the Boyne Estuary SPA could also be indirectly affected by water quality impacts from the bridge works and potentially by invasive species introduction in the absence of appropriate mitigation measures.
Cumulative impacts may also arise regarding water quality as the Boyne Catchment and Estuary is already affected by agricultural, septic tank and landfill pollution as well as being subject to heavy modification over the years which affects the water quality and habitats in also. Conclusion The potential for impacts on the River Boyne and River Blackwater SAC, River Boyne and River Blackwater SPA, Boyne Coast and Estuary SAC and Boyne Estuary SPA have been identified. Obelisk Bridge is located over the main channel of the River Boyne within the River Boyne and River Blackwater SAC and River Boyne and River Blackwater SPA. The Boyne Coast and Estuary SAC and the Boyne Estuary SPA are located downstream of this site, less than 10km of this bridge. There is potential for direct, indirect and cumulative impacts to arise as a result of the works. Mitigation will be required. In a pre-assessment Screening, mitigation cannot be provided. Therefore, a Natura Impact Statement is required for the proposed remedial works.
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