Obelisk Bridge, Co. Louth NATURA IMPACT STATEMENT
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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. _________________________________________________________________________________ www.ecofact.ie 2 Obelisk Bridge, Co. Louth – Rehabilitation Works Natura Impact Statement_______________________________________________________________ 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 ........................................................................................................................................