Irish Water Report
Natura Impact Statement as part of the Milltown Waste Water Discharge License Application
Contents
Introduction 3 Legislative Context 3
Methodology 5 Guidance Followed 5 Stages Involved in the Appropriate Assessment Process 6 Field Walkover Surveys 6 Consultation 7
Screening 7
Stage 2: Appropriate Assessment 8 Description of the Project 8 Description of the Receiving Environment and Monitoring Results 9 Waste Assimilative Capacity 10 Field Walkover Survey 11 Description of the Natura 2000 Site Affected 12 Lough Corrib SAC 12 Description of the Conservation Interests of the SAC 13 Annex I Habitats 13 Annex II Species 15 Impact Prediction 21 Impacts on Water Quality 21 Impacts on Annex I Habitats 22 Impacts on Annex II Species 24 Mitigation Measures 25 Stage 2 Appropriate Assessment Conclusion Statement 25
References 26
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Introduction
This report provides an Appropriate Assessment (AA) of the Waste Water Treatment Plant (WwTP) at Milltown, Co Galway, for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007), as amended. It assesses whether the operation of the plant, alone or in combination with other plans and projects, is likely to have significant effects on a European Site(s) in view of best scientific knowledge and the conservation objectives of the site(s). European Sites are those identified as sites of European Community importance designated as Special Areas of Conservation under the Habitats Directive or as Special Protection Areas under the Birds Directive.
This report follows the guidance for AA published by the Environmental Protection Agency’s (EPA) ‘Note on Appropriate Assessments for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007)’ (EPA, 2009); and takes account of the Department of the Environment, Heritage and Local Government’s guidelines ‘Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities’ (DoEHLG, 2009) and Circular L8/08 ‘Water Services Investment and Rural Water Programmes – Protection of Natural Heritage and National Monuments’ (DoEHLG, 2008).
Legislative Context The Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Flora, better known as “The Habitats Directive”, provides legal protection for habitats and species of European importance. Articles 3 to 9 provide the legislative means to protect habitats and species of Community interest through the establishment and conservation of an EU-wide network of sites known as Natura 2000. These are Special Areas of Conservation (SACs) designated under the Habitats Directive and Special Protection Areas (SPAs) designated under the Conservation of Wild Birds Directive (79/409/ECC) as codified by Directive 2009/147/EC.
Articles 6(3) and 6(4) of the Habitats Directive set out the decision-making tests for plans and projects likely to affect Natura 2000 sites (Annex 1.1). Article 6(3) establishes the requirement for Appropriate Assessment (AA):
Any plan or project not directly connected with or necessary to the management of the [Natura 2000] site but likely to have a significant effect thereon, either individually or in combination with other plans or projects, shall be subjected to appropriate assessment of its implications for the site in view of the site’s conservation objectives. In 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.
Article 6(4) states:
If, in spite of a negative assessment of the implications for the [Natura 2000] site and in the absence of alternative solutions, a plan or project must nevertheless be carried out
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for imperative reasons of overriding public interest, including those of a social or economic nature, Member States 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.
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Methodology
Guidance Followed Both EU and national guidance exists in relation to Member States fulfilling their requirements under the EU Habitats Directive, with particular reference to Article 6(3) and 6(4) of that Directive. The methodology followed in relation to this AA has had regard to the following guidance:
Note on Appropriate Assessments for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007). Environmental Protection Agency, (EPA, 2012, Version 2.2).
Appropriate Assessment of Plans and Projects in Ireland: Guidance for Planning Authorities. Department of Environment, Heritage and Local Government, (DoEHLG, 2010).
Circular L8/08 – Water Services Investment and Rural Water Programmes – Protection of Natural Heritage and National Monuments. Department of Environment, Heritage and Local Government, (DoEHLG, 2008).
Communication from the Commission on the Precautionary Principle. Office for Official Publications of the European Communities, Luxembourg, (EC, 2000a).
Managing Natura 2000 Sites: the provisions of Article 6 of the ‘Habitats’ Directive 92/43/EEC, Office for Official Publications of the European Communities, Luxembourg, (EC, 2000b).
Assessment of plans and projects significantly affecting Natura 2000 sites: Methodological guidance on the provisions of Articles 6(3) and (4) of the Habitats Directive 92/43/EEC. Office for Official Publications of the European Communities, Brussels (EC, 2001).
Guidance document on Article 6(4) of the ‘Habitats Directive’ 92/43/EEC – Clarification of the concepts of: alternative solutions, imperative reasons of overriding public interest, compensatory measures, overall coherence, opinion of the Commission. Office for Official Publications of the European Communities, Luxembourg, (EC, 2007).
Nature and biodiversity cases: Ruling of the European Court of Justice. Office for Official Publications of the European Communities, Luxembourg (EC, 2006).
Marine Natura Impact Statements in Irish Special Areas of Conservation: A working document, National Parks and Wildlife Service, Dublin (NPWS, 2012).
European Communities (Birds and Natural Habitats) Regulations, 2011 (S.I. No.477 of 2011).
Interpretation Manual of European Union Habitats. Version EUR 28. European Commission (EC, 2013).
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Stages Involved in the Appropriate Assessment Process
Stage 1: Screening / Test of Significance This process identifies whether the WwTP discharge is directly connected to or necessary for the management of a European Site(s); and identifies whether the discharge is likely to have significant impacts upon a European Site(s) either alone or in combination with other projects or plans.
The output from this stage is a determination for each European Site(s) of not significant, significant, potentially significant, or uncertain effects. The latter three determinations will cause that site to be brought forward to Stage 2.
Stage 2: Appropriate Assessment This stage considers the impact of the WwTP discharge on the integrity of a European Site(s), either alone or in combination with other projects or plans, with respect to (1) the site’s conservation objectives; and (2) the site’s structure and function and its overall integrity. Additionally, where there are adverse impacts, an assessment of the potential mitigation of those impacts
The output from this stage is a Natura Impact Statement (NIS). This document must include sufficient information for the EPA to carry out the appropriate assessment. If the assessment is negative, i.e. adverse effects on the integrity of a site cannot be excluded, then the process must consider alternatives (Stage 3) or proceed to Stage 4.
Stage 3: Assessment of Alternatives This process examines alternative ways of achieving the objectives of the project or plan that avoid adverse impacts on the integrity of the European Site. This assessment may be carried out concurrently with Stage 2 in order to find the most appropriate solution. If no alternatives exist or all alternatives would result in negative impacts to the integrity of the European sites then the process either moves to Stage 4 or the project is abandoned.
Stage 4: 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.
Field Walkover Surveys Field walkover surveys were undertaken by a suitably qualified ecologist on the 1st of March 2016 to identify the potential for qualifying species and habitats in the surrounding environs of the WwTP discharge. Reference was made to the Stage 1 Screening and Stage 2 Appropriate Assessment reports for the Milltown sewerage scheme, completed by Tobin Consulting Engineers and Ecofact Environmental Consultants in 2008 (Tobin, 2008).
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Consultation The EPA, as the competent authority, will seek NPWS advice as may be required in reaching their decision on a WwTP discharge. The NPWS can only communicate with the applicant (i.e. Irish Water) on request from the competent authority, when the formal application process to the competent authority has already commenced.
Screening
The village of Milltown, located along the banks of the River Clare approximately 15km upstream of Tuam. The village is currently dependant on private septic tanks and temporary package treatment plants to cater for the collection, treatment and disposal of foul wastewater from dwellings and commercial properties within its catchment area. The proposed discharge point of the new WwTP is directly into the River Clare which forms part of Lough Corrib SAC. As the discharge is directly into a Natura 2000 site, the WwTP will be brought forward for a Stage 2 Appropriate Assessment. The nearest other connected Natura 2000 site is Lough Corrib SPA, but as this is ca. 44km downstream of the discharge point this site is not considered further in the Appropriate Assessment process.
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Stage 2: Appropriate Assessment
Lough Corrib SAC, which have been determined as requiring AA, is described and all the potential impacts resulting from the Milltown WwTP discharge are discussed in relation to the conservation objectives of this designated site.
Description of the Project
The current population equivalent for the agglomeration is 504p.e. (residential and non-domestic) and the estimated 2022 load will be 535p.e. Based on a loading of 225l/pp/day the dry weather flow for the current discharge is calculated at 0.00131m3/sec, with the 2022 dry weather flow calculated at 0.00139m3/sec. The long-term 95-percentile flow for the River Clare (Source Gauge at Millbrook House upstream of Milltown) is 0.87m3/sec.
A new wastewater treatment plant and pumping station for Milltown is currently (March 2016) under construction as part of a Design Build Operate Contract which includes the Claregalway & Milltown Wastewater Treatment Plants and Pumping Stations. Treated effluent from the Milltown Wastewater Treatment Plant will discharge to the Clare River at the townland of Cartron to the west of Milltown. The Clare River flows south-westerly, where it drains into Lough Corrib at the townland of Coarsefield. The Lough Corrib cSAC extends upstream along the Clare River and includes the river at the proposed discharge point. The collection system, which was constructed in 2014, has been designed as a completely separate system and there are no stormwater overflows to surface water sewers within the agglomeration. Furthermore there are no secondary discharges to receiving waters from pumping stations within the agglomeration. Previous to this development, the village of Milltown had no public waste water treatment plant.
The new Milltown Wastewater Treatment Plant will have a design Population Equivalent (PE) of 1,400. The treatment plant currently under construction is based on Sequential Batch Reactors (SBR). The plant design includes the following: Preliminary treatment screening / grit removal system including, screening, dewatering, manual by-pass screen and screening / grit collection; Biological treatment based on two Sequential Batch Reactors; A fine bubble diffused aeration system with dissolved oxygen control; A treated wastewater balance tank; A Tertiary treatment filter; and A Picket Fence Thickener.
The proposed waste water treatment plant will treat the waste water to the following standards to exceed the requirements set down in the Urban Wastewater Treatment Directive (S.I. 254 / 2001): 25mg/l B.O.D.; 125mg/l C.O.D.; 35mg/l Suspended Solids;
The plant is expected to have an effluent with Ammonia of 40mg/l and Orthophosphate of 10mg/l with no nutrient removal process required.
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Description of the Receiving Environment and Monitoring Results The WwTP discharges directly to the River Clare (E140097 N262931) which is designated as part of Lough Corrib SAC.
Monitoring data from locations both upstream and downstream of the proposed discharge point is are presented in Table 1.0. For the relevant parameters, water quality meets the standard for Good water quality status on all occasions. With the exception of one measurement for Ammonia (Nov 15) water quality also meets the standard for High water quality status.
Table 1.0: Monitoring Data from River Clare Total ortho- Oxidised Ammonia- BOD Dissolved Phosphate Nitrogen Parameter Total (as N) (Total) Oxygen (as P) (as N) ≤0.14 (good) ≤2.6 (good) ≤0.075 (good) SW EQS ≤0.090 (high) ≤2.2 (high) ≤0.045 (high)
Bridge 1.5km u/s Milltown 20-Jan-14 0.026 0.5 89 0.01 1.6 09-Jun-14 0.01 0.5 101 0.005 0.77 17-Jul-14 0.01 0.5 103 0.005 0.65 20-Oct-14 0.01 1.2 81 0.005 0.66 19-Jan-15 0.027 0.5 85 0.011 1.7 07-May-15 0.021 0.5 89 0.005 0.1 23-Sep-15 0.01 0.5 85 0.012 1.1 05-Nov-15 0.13 0.5 100 0.011 1.3 Fartamore Bridge 20-Jan-14 0.021 0.5 90 0.005 1.7 09-Jun-14 0.01 0.5 109 0.005 0.72 17-Jul-14 0.01 0.5 109 0.005 0.64 20-Oct-14 0.01 1 83 0.005 0.72 19-Jan-15 0.01 0.5 87 0.012 1.8 07-May-15 0.01 0.5 91 0.018 0.1 23-Sep-15 0.01 0.5 87 0.017 0.93 05-Nov-15 0.01 0.5 97 0.011 0.86
The EPA monitor the River Clare for biological water quality (EPA, 2016)1. Upstream of Milltown (Br 1.5km u/s Milltown – RS30C010100) the EPA assigned a Q3-4 rating to the river in 2010 indicating Moderate water quality status. The river ca. downstream of the proposed discharge location at Fartamore Bridge (RS30C010300) was assigned a Q4 rating in 2006 indicating Good water qualty. Orthophosphate levels in the River Clare were reduced in the period 2011-2013 compared with previous years (EPA, 2013).
The section of the River Clare running through Milltown has not been assigned a WFD (2010- 2012) status. The section upstream of Milltown has been assigned Moderate WFD (2010-2012)
1 http://gis.epa.ie/Envision
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status (EPA, 2015), while the section downstream of Fartamore Bridge has been assigned Good WFD (2010-2012) status. The River Clare is classed as ‘At risk of not achieving Good status’.
The discharge point is over 44km upstream of the main waterbody of Lough Corrib. The EPA class Lough Corrib as a mesotrophic lake having Moderate water quality status (based on a 2009 sampling year). Lower Lough Corrib has also been assigned Moderate WFD (2010-2012) status and is classed as ‘Possibly at risk of not achieving Good status’.
Waste Assimilative Capacity Table 2.0 summaries the assimilative capacity calculations which are based on the 2022 estimated loading of 535p.e., 95%ile river flow and water quality standards in the European Communities Environmental Objectives (Surface Water) Regulations, 2009 (S.I. No. 272 of 2009). Assimilative capacity calculations use both actual background concentrations and the ‘notionally clean river’ approach.
Table 2.0: Assimilative capacity calculations at estimated 2022 loadings of 535p.e. for actual background concentrations and for a notionally clean river.
Parameter Background Predicted EQS* (mg/l) (mg/l) downstream quality (mg/l)
BOD Actual Background 0.5875 1.21 ≤2.6 Notionally Clean 0.260 0.56 Ammonia Actual Background 0.0305 0.125 ≤0.14 Notionally Clean 0.008 0.080 Orthophosphate Actual Background 0.008 0.032 ≤0.075 Notionally Clean 0.026 0.068 *European Communities Environmental Objectives (Surface Waters) Regulations 2009, S.I. No. 272 of 2009 (95%ile standards presented for Good status waters).
At estimated 2022 loadings, and based on effluent treatment standards identified, the River Clare in Milltown has the capacity to assimilate BOD, Ammonia and Orthophosphate based on actual and notionally clean background concentrations, while maintaining Good water quality status downstream.
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Field Walkover Survey The River Clare in the vicinity of the proposed discharge point is a wide (ca. 12m) comprising of fast glide habitat. The river was in flood at the time of survey due to heavy rain the previous day and the river substrate was not visible. The banks in this section of the river are steep-cut and ca. 0.5m high with adjacent land use comprising improved grassland. There is a narrow band of club rush at the margins of the river which transitions to a band of Photo 1: River Clare at Milltown WwTP grassland and scrub at the field edges.
No Annex I habitats were recorded in the River Clare or surrounding lands in the vicinity of the new WwTP. The river habitat is suitable for otter, lamprey, crayfish and salmon, all Annex II species for which Lough Corrib SAC is designated. No signs of otter were recorded, though recent heavy rain and high river flows at the time of the site visit were likely to have removed any signs.
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Description of the Natura 2000 Site Affected
Lough Corrib SAC2
Lough Corrib is situated to the north of Galway city and is the second largest lake in Ireland, with an area of approximately 18,240 ha (the entire site is 20,556 ha). The lake can be divided into two parts: a relatively shallow basin, underlain by Carboniferous limestone, in the south, and a larger, deeper basin, underlain by more acidic granite, schists, shales and sandstones to the north. The surrounding lands to the south and east are mostly pastoral farmland, while bog and heath predominate to the west and north. A number of rivers are included within the cSAC as they are important for Atlantic Salmon. These rivers include the Clare, Grange, Abbert, Sinking, Dalgan and Black to the east, as well as the Cong, Bealanabrack, Failmore, Cornamona, Drimneen and Owenriff to the west. In addition to the rivers and lake basin, adjoining areas of conservation interest, including raised bog, woodland, grassland and limestone pavement, have been incorporated into the site.
The shallow, lime-rich waters of the southern basin of Lough Corrib support one of the most extensive beds of stoneworts (Charophytes) in Ireland, with several species mixed with submerged pondweeds, Shoreweed and Water Lobelia. In contrast, the northern basin contains more oligotrophic and acidic waters, without Chara species, but with Shoreweed, Water Lobelia, Pipewort, Quillwort, Alternate Water-milfoil and Slender Naiad. The Slender Naiad is listed under the Flora (Protection) Order, and is an Annex II species under the E.U. Habitats Directive.
Large areas of reedswamp vegetation, dominated by varying mixtures of Common Reed and Common Club-rush, occur around the margins of the lake. Reedswamp usually grades into species-rich marsh vegetation. Alkaline fen vegetation is widespread around the lake margins and includes, amongst the typically diverse range of plants, the Slender Cottongrass, a species protected under the Flora (Protection) Order.
This large site contains four discrete raised bog areas and is selected for active raised bog, degraded raised bog, Rhynchosporion and bog woodland. Limestone pavement occurs along much of the shoreline in the lower Corrib basin, and supports a rich and diverse flora. Open areas of orchid-rich calcareous grassland are also found in association with the limestone exposures. A number of the rivers in the site support submerged and floating vegetation of the Ranunculion fluitantis and Callitricho-Batrachion, including mosses. The rare and Annex II-listed Slender Green Feather-moss (Drepanocladus vernicosus) is found at the fen at Gortachalla, north-east of Moycullen.
In terms of fauna, the lake is rated as an internationally important site for waterfowl. Otter and Irish Hare have been recorded regularly within this site. Both of these species are listed in the Red Data Book and are legally protected by the Wildlife Act, 1976. Otter is also listed on Annex II of the E.U. Habitats Directive. A population of Freshwater Pearl Mussel (Margaritifera margaritifera), a species listed on Annex II of the E.U. Habitats Directive, occurs within the site. White-clawed Crayfish (Austropotamobius pallipes), also listed on Annex II, is well distributed
2 Extracted from NPWS Site Synopsis (NPWS, 2013c)
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throughout Lough Corrib and its in-flowing rivers over limestone. A summer roost of Lesser Horseshoe Bat, another Annex II species, occurs within the site - approximately 100 animals were recorded here in 1999.
The main threats to the quality of this site are from water polluting activities resulting from intensification of agricultural activities on the eastern side of the lake, uncontrolled discharge of sewage which is causing localised eutrophication of the lake, and housing and boating development, which is causing the loss of native lakeshore vegetation.
Description of the Conservation Interests of the SAC
Annex I Habitats Lough Corrib SAC supports 14 Annex I habitats: Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae) [3110] Hard oligo-mesotrophic waters with benthic vegetation of Chara spp. [3140] Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho- Batrachion vegetation [3260] Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco- Brometalia) (* important orchid sites) [6210] Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae) [6410] Active raised bogs [7110] Degraded raised bogs still capable of natural regeneration [7120] Depressions on peat substrates of the Rhynchosporion [7150] Calcareous fens with Cladium mariscus and species of the Caricion davallianae [7210] Petrifying springs with tufa formation (Cratoneurion) [7220] Alkaline fens [7230] Limestone pavements [8240] Old sessile oak woods with Ilex and Blechnum in the British Isles [91A0] Bog woodland [91D0]
Lake Habitats The southern basin of Lough Corrib into which the River Clare discharges, supports extensive Charophyte beds, though lacks the protected plant Slender Naiad which is found in the northern basin (NPWS, 2013c). These lake habitats are located ca. 44km downstream of the discharge point and due to this significant distance are not considered to have the potential to be impacted by the discharge.
Spring and Fen Habitats Fen and spring habitats may occur in association with the southern basin lakeshore edges into which the River Clare discharges. In particular calcareous fen is known from the southeastern corner of the lake along the northern section of Addergoole Bog. At their closest point, these wetland habitats could be located over 40km downstream of the discharge point and due to this significant distance are not considered to have the potential to be impacted by the discharge.
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Floating River Vegetation Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho- Batrachion vegetation (3260) (Floating River Vegetation) is characterised by the abundance of water-crowfoots Ranunculus spp and/or other aquatic plants and mosses. Floating mats of aquatic vegetation may modify water flow, promote fine sediment deposition, and provide shelter and food for fish and invertebrate animals. The River Clare is likely to support floating river vegetation, though water turbidity at the time of survey prevented confirming the presence of this habitat. Potential impacts to this habitat therefore requires consideration.
Limestone Pavement & Grassland Limestone pavement occurs particularly in the southern basin of Lough Corrib, and orchid rich grasslands are associated with this habitat. Milltown WwTP is not within or adjacent to any Annex I habitat (Tobin, 2008) and grassland on the banks downstream of the discharge comprises improved or semi-improved wet grassland. While limestone pavement, Molinia meadow and orchid rich grasslands may occur within the SAC close to where the River Clare discharges, these habitats do not have the potential to be influenced by the discharge.
Oak woodland Sessile oak woodland is known from the Hill of Doon in the northwest of the SAC. This is a terrestrial habitat with no potential to be impacted by the discharge.
Bog Habitats Addergoole Bog, supporting raised bog habitats and bog woodland, is located north of the River Clare to the west of Claregalway. It iss not within the potential zone of influence of surface waters of the River Clare, and a significant distance downstream of the discharge.
Table 4.0: Qualifying Habitats along Surveyed Stretch
Site Qualifying Habitats Present within potential zone of influence of the discharge
Oligotrophic waters No
Hardwater lakes No
Floating River Vegetation Yes
Orchid rich calcareous grassland No Lough Corrib Molinia meadows No SAC Active raised bogs No
Degraded raised bogs No
Rhynchosporion depressions No
Calcareous fens No
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Petrifying springs No
Alkaline fens No
Limestone pavements No
Old oak woodlands No
Bog woodland No
Annex II Species Lough Corrib SAC is selected for the following 9 Annex II species: Margaritifera margaritifera (Freshwater Pearl Mussel) [1029] Austropotamobius pallipes (White-clawed Crayfish) [1092] Petromyzon marinus (Sea Lamprey) [1095] Lampetra planeri (Brook Lamprey) [1096] Salmo salar (Salmon) [1106] Rhinolophus hipposideros (Lesser Horseshoe Bat) [1303] Lutra lutra (Otter) [1355] Drepanocladus vernicosus (Slender Green Feather-moss) [1393] Najas flexilis (Slender Naiad) [1833]
White-clawed Crayfish Crayfish are typically found in unpolluted shallow riffley watercourses wherever limestone or its derivative glacial drift is significant (Reynolds, 1998). Juveniles live among submerged tree- roots, gravel or aquatic plants, while larger crayfish must have stones to hide under, or earthen banks in which to burrow. Crayfish require some input of organic material, primarily leaves, as a source of food. They are commonly reported from moderately polluted sites (Demers et al, 2005), though they can suffer significant losses during severe pollution events. Reynolds (1998) notes that eutrophication can lead to luxuriant plant growth, which in turn traps silt and can result in deoxygenation at night, leading to loss of crayfish habitat. Typical site specific conservation objectives set a target of Q3-4 for crayfish. The River Clare is known to support this species (NPWS, 2013b; NBDC, 20163). The overall conservation status for this species is Inadequate, with trend stable (NPWS 2013b).
Lamprey Sea and river lamprey are anadromous species, spending part of their life cycle in the marine environment and returning to natal watercourses to spawn. Adult fish can migrate long distances into freshwater but artificial barriers to passage can result in spawning being confined to downstream of these barriers (NPWS, 2013b). Brook lamprey completes its life cycle in freshwater, spawning in gravels in the upper reaches of rivers, with larval development occurring in burrows in soft sediments in slower flowing waters downstream. The River Clare is known to support brook lamprey(O’Connor, 2007). The highest densities were recorded in upstream tributaries, and while the upper River Clare around Milltown has no optimal habitat some
3 http://maps.biodiversityireland.ie/#/Map
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juveniles were still recorded. The overall conservation status for this species is Favourable (NPWS 2013b). Sea lamprey are confined to the areas of the Corrib catchment below the Galway regulating weir (O’Connor, 2007).
Atlantic Salmon The Atlantic salmon Salmo salar is an anadromous species using rivers to reproduce and as nursery areas during their juvenile phase (NPWS, 2013b). Salmon are present throughout the Nore catchment (NPWS, 2013b). The species is dependent on good water quality requiring clean (Q4) water for spawning and early life stages. Aside from water quality, other threats noted relate to mortality at sea (NPWS 2013b). IFI (Kelly et al, 2014) surveyed the River Clare in 2014 at Corofin and Kiltroge Castle Bridge (2km east of Claregalway) recording salmon at both sites. At Corofin roach was the most abundant fish species recorded followed by perch, pike, brown trout, salmon and stone loach. At Kiltroge Castle Bridge roach was again the most abundant species, followed by salmon, brown trout, perch, pike and European eel. The overall conservation status for this species is Inadequate, with trend stable (NPWS 2013b).
Freshwater Pearl Mussel There is no freshwater pearl mussel population in the River Clare or downstream in Lough Corrib, with the Lough Corrib SAC population confined to the Owenriff River in the northwest of the catchment (NPWS, 2013b).
Otter Otter are known to be common in the River Clare as indicated by recent records on the NBDC website, previous ecological surveys of the Milltown area (Tobin, 2008) and NPWS (2013b). 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. The overall assessment of the conservation status of otter is 'Favourable' (NPWS, 2013b).
Other qualifying interests Lesser horseshoe bat have no potential to be impacted by the surface water discharge. The aquatic plant Slender Naiad is found in the northern basin, and is considered to be beyond the potential zone of influence of the discharge as the River Clare enters the southern basin. Slender Green Feather-moss is known from the Moycullen area to the west of Lough Corrib beyond the potential zone of influence of the discharge.
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Table 5.0: Qualifying Species along Surveyed Stretch
Site Qualifying Species Observed or signs of Suitable Habitat Present species presence with Potential Zone of Influence of the discharge
Lough Corrib SAC Freshwater Pearl Mussel No No
White-clawed Crayfish No Yes
Sea Lamprey No No
Brook Lamprey No Yes
Salmon No Yes
Lesser Horseshoe Bat No No
Otter No Yes
Slender Green Feather- No No moss Slender Naiad No No
Conservation Objectives of Lough Corrib SAC4
Article 6 of the Habitats Directive states that:
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 of the site in view of the site’s conservation objectives.
The importance of a site designated under the Habitats Directive is defined by its qualifying features or interests. Qualifying interests for any Natura 2000 site are listed on a pro forma, called the Natura 2000 standard data form, which forms the basis of the rationale behind designation, and informs the Conservation Management Plan for targeted management and monitoring of key species and habitats.
Favourable conservation status of a habitat is achieved when: Its natural range, and area it covers within that range, are stable or increasing; 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:
4 NPWS (2015) Conservation objectives for Lough Corrib SAC [000297]. Generic Version 4.0. Department of Arts, Heritage and the Gaeltacht.
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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; 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.
Detailed conservation objectives for the qualifying interests of the SAC have yet to be published. For qualifying interests which have the potential to be impacted by the discharge, where available, reference was made to detailed objectives for another SAC (River Barrow and River Nore SAC 002162) with the same qualifying features.
Floating River Vegetation Attribute: Habitat distribution; Target: No decline, subject to natural processes. Attribute: Habitat Area; Target: Area stable or increasing, subject to natural processes. Attribute: Hydrological regime - river flow, Target: Maintain appropriate hydrological regimes. Attribute: Hydrological regime – groundwater discharge; Target: The groundwater flow to the habitat should be permanent and sufficient to maintain tufa formation. Attribute: Substratum composition - particle size range; Target: The substratum should be dominated by large particles and free from fine sediments. Attribute: Water chemistry – minerals; Target: The groundwater and surface water should have sufficient concentrations of minerals to allow deposition and persistence of tufa deposits. Attribute: Water quality – suspended sediment; Target: The concentration of suspended solids in the water column must be sufficiently low to prevent changes in species composition or habitat condition. Attribute: Water quality – nutrients; Target: The concentration of nutrients in the water column must be sufficiently low to prevent changes in species composition or habitat condition. Attribute: Vegetation composition - typical species; Target: Typical species of the relevant habitat sub-type reach favourable status. Attribute: Floodplain connectivity – area; Target: The area of active floodplain at and upstream of the habitat should be maintained.
White-clawed crayfish Attribute: Distribution; Target: No reduction from baseline. Attribute: Population structure -recruitment; Target: Juveniles and/or females with eggs in at least 50% of positive samples. Attribute: Negative Indicator Species;
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Target: No alien crayfish species. Attribute: Disease; Target: No instances of disease. Attribute: Water quality; Target: At least Q3-4 at all sites sampled by the EPA. Attribute: Habitat quality - heterogeneity; Target: No decline in heterogeneity or habitat quality.
Brook Lamprey Attribute: Distribution; Target: Access to all watercourses down to first order streams. Attribute: Population structure of juveniles; Target: At least three age/size groups of brook/river lamprey present. Attribute: Juvenile density in fine sediment; Target: Mean catchment juvenile density of brook/river lamprey at least 2/m2. Attribute: Extent and distribution of spawning habitat; Target: No decline in extent and distribution of spawning beds. Attribute: Availability of juvenile habitat; Target: More than 50% of sample sites positive.
Atlantic Salmon Attribute: Distribution; Target: 100% of river channels down to second order accessible from estuary. Attribute: Adult spawning fish; Target: Conservation limit (CL) for each system consistently exceeded. Attribute: Salmon fry abundance; Target: Maintain or exceed 0+ fry mean catchment-wide abundance threshold value. Currently set at 17 salmon fry/5min sampling. Attribute: Out-migrating smolt abundance; Target: No significant decline. Attribute: Number and distribution of redds; Target: No decline in number and distribution of spawning redds due to anthropogenic causes. Attribute: Water quality; Target: At least Q4 at all sites sampled by EPA.
Otter Attribute: Distribution; Target: No significant decline. Attribute: Extent of terrestrial habitat; Target: No significant decline. Attribute: Extent of marine habitat; Target: No significant decline. Attribute: Extent of freshwater habitat; Target: No significant decline. Attribute: Extent of freshwater lake/lagoon habitat; Target: No significant decline.
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Attribute: Couching sites and holts; Target: No significant decline. Attribute: Fish biomass available; Target: No significant decline.
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Impact Prediction
Impacts on Water Quality The aquatic conservation interests of Lough Corrib SAC are directly dependant on the aquatic environment and as the Milltown WwTP will discharge directly to the River Clare which forms part of Lough Corrib SAC, there is a direct connection between this facility and the ecological receptors of the SAC.
With the operation of a new wastewater scheme replacing ineffective septic tanks and wastewater systems, pollutants entering the River Clare will be significantly reduced. The River Clare has the capacity to assimilate the proposed current and future discharge levels, which will be within the requirements of the UWWT Regulations, and there is no evidence to suggest that there will be a significant deterioration in water quality downstream.
Cumulative impacts in the catchment possibly pose the greatest risk to the conservation objectives. The potential threat(s) of the Milltown WwTP on water quality (long term or single event) is greatly increased when taken in combination with other water quality concerns in the catchment.
Most phosphorus entering the Corrib catchment (WRBD, 2010) is from diffuse sources (90%) mainly agriculture (80%). The Corrib Water Management Unit Action Plan identified 8 WwTPs in the wider Corrib catchment, though none were discharging into the River Clare (at the time of publication). Risks are identified from Oughterard WwTP which requires a new plant, and Cong and Shrule WwTPs which require implementation of a performance management system. Other point pressures include 11 Section 4 licenses, 4 IPPC licenses and 4 Water Treatment Plants.
There are currently two WwTP’s operational in the River Clare catchment. The Tuam WwTP discharges into the River Clare ca. 12km downstream of Milltown. The EPA website indicates that this plant was compliant with UWWT standards (2014) and downstream water quality is classed as Good (Q4-2012) by the EPA. Upstream of Milltown the Dunmore WwTP, which discharges into the Sinking River, is also operating in compliance with UWWT standards. A proposed wastewater treatment plant at Claregalway, ca. 25km downstream of Tuam, has been designed and built to ensure effluent is compliant with UWWT standards. The treatment process will include phosphorus removal and the discharge standards have been set with consideration of existing upstream water quality influenced by the Tuam WwTP and existing poorly treated/untreated discharges from Milltown. The Claregalway discharge will not result in a deterioration in water quality status downstream in the River Clare. A study by Hydro-G (2008) found that the cumulative impact on the River Clare’s water quality from the existing WwTP in Tuam and the two proposed WwTPs at Milltown and Claregalway will be negligible.
A review of Galway County Councils planning website indicated there are no other current significant developments in Milltown.
Other impacts which have the potential to act cumulatively and impact on the SAC/SPA result from the following:
Chemical fertiliser application to agricultural lands (the main fertilisers in use supply nitrogen, phosphorus, potassium and sulphur);
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Agricultural practices such as ploughing leads to greater mineralisation and nitrification, and in the case of old grassland, it can result in an increase in the release of nitrogen over a number of years (OECD, 1986); Artificial drainage increases nitrate leaching and reduce the morphological qualities of watercourses, thereby reducing the quality of habitat for flora and fauna; Endocrine disruptors in domestic sewage, including the main active component in the oral contraceptive pill, can interfere with the endocrine system of plants and animals which controls a wide range of processes including metabolism, growth and reproduction. Effects include a high degree of intersexuality downstream of sewage works (Routledge et al. 1998); Forestry may alter water quality indirectly through increased evaporation losses and hence an increase in solute concentrations; and On-site wastewater treatment systems, poorly performing septic tank units and other small effluent systems can be significant sources of nutrients to rivers.
The new Milltown WwTP has been designed to a capacity well in exceedance of the current population equivalent. It has also been designed to produce a high quality effluent which will ensure that the WwTP will not lead to any deterioration in downstream water quality status. It is expected that with the decommissioning of poor quality effluent discharges that the new scheme will lead to improvements in water quality in the River Clare. While there are a variety of pressures on water quality in the catchment, the discharge from Milltown WwTP will not contribute significantly to these, and therefore will not contribute to significant effects on Lough Corrib SAC or any other Natura 2000 site, while operating at current and future predicted PE’s. The combined effect in the River Clare catchment of controlling and effectively treating the discharges from Milltown and Claregalway is expected to be positive. It is important however that the WwTP is monitored to ensure it continues to provide effective treatment.
Impacts on Annex I Habitats
The only habitat with the potential to be impacted by a discharge from Milltown WwTP is floating river vegetation within the River Clare. The other habitats are associated with Lough Corrib which is ca. 44km downstream of the discharge point and considered to be beyond the potential zone of influence of the discharge.
Floating river vegetation is potentially the only habitat in direct proximity to the proposed discharge and is therefore most at risk as it may be present within the mixing/dilution zone of the treated effluent. Water quality (particularly phosphorus and nitrates) strongly influences the species composition, extent and condition of riverine plant communities. The key parameters include alkalinity, pH, nitrate, phosphate, potassium and suspended solids. Eutrophication is regarded as the major water quality issue currently affecting plant communities in British rivers (Environment Agency 2000). The process of eutrophication and its impact on macrophyte communities varies, depending upon river type and catchment. The effects of eutrophication on aquatic macrophytes are documented (Haslam 1978; Spink et al. 1993; Mainstone et al. 2000) as usually causing a shift in community composition and increased biomass. Increasing nutrient supply will lead to an overall reduction in the number of species, with a loss of Ranunculus spp. and an increase in pollution-tolerant species such as Potamogeton pectinatus, Myriophyllum spicatum, Sparganium emersum, Schoenoplectus lacustris and filamentous algae. More extreme
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nutrient increases lead to an overall impoverishment of the plant community, with algae dominating.
The River Clare at Milltown has available dilution for the discharge while still maintaining Good water quality status downstream. The effluent is proposed to be treated to a high standard and the new WwTP will result in the treatment of discharges that are currently uncontrolled and poorly treated, if at all. As no water quality impacts are predicted, there will be no adverse effect to Floating river vegetation or any other Annex I habitat within Lough Corrib SAC.
Table 7.0: Qualifying Habitats Potentially Impacted by WwTP Discharge
Qualifying Habitats Potential Impacts Brief Explanation Mitigation required
No Habitat associated with Lough Corrib No and due to the distance involved it is Oligotrophic waters beyond the potential zone of influence of the discharge. No Habitat associated with Lough Corrib No and due to the distance involved it is Hardwater lakes beyond the potential zone of influence of the discharge. Yes Good water quality status will be No maintained downstream of the WwTP Floating River Vegetation due to appropriate treatment of the effluent therefore no adverse effects predicted. Orchid rich calcareous No Habitat not present within the potential No grassland zone of influence of the discharge. No Habitat not present within the potential No Molinia meadows zone of influence of the discharge. No Habitat not present within the potential No Active raised bogs zone of influence of the discharge. No Habitat not present within the potential No Degraded raised bogs zone of influence of the discharge. Rhynchosporion No Habitat not present within the potential No depressions zone of influence of the discharge. No Habitat associated with Lough Corrib No and due to the distance involved it is Calcareous fens beyond the potential zone of influence of the discharge. No Habitat associated with Lough Corrib No and due to the distance involved it is Petrifying springs beyond the potential zone of influence of the discharge. No Habitat associated with Lough Corrib No Alkaline fens and due to the distance involved it is beyond the potential zone of influence
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of the discharge. No Habitat not present within the potential No Limestone pavements zone of influence of the discharge. No Habitat not present within the potential No Old oak woodlands zone of influence of the discharge. No Habitat not present within the potential No Bog woodland zone of influence of the discharge.
Impacts on Annex II Species
Four species have been identified as having the potential to be impacted by the proposed discharge - white-clawed crayfish, brook lamprey, salmon and otter. Suitable habitat for all of these species is present in the River Clare in the vicinity of Milltown. Given the quality of the discharge, the potential for significant impacts to the aquatic qualifying interests of Lough Corrib SAC from the discharge is considered negligible. Salmon and lamprey require Good water quality status, particularly for early life stages, and these conditions will be supported by the new sewerage scheme. Improved water quality will also benefit any crayfish or otter populations in the vicinity of the discharge. No significant adverse effects to the conservation status of the aquatic qualifying species (salmon, lamprey, crayfish and otter) of Lough Corrib SAC are therefore anticipated as a result of the waste water discharge from Milltown WwTP.
Table 8.0: Qualifying Species Potentially Impacted by WwTP Discharge
Qualifying Species Potential Brief Explanation Mitigation Impact Required
Freshwater Pearl No Species not present within the potential zone of No Mussel influence of the discharge. White-clawed Yes Good water quality status will be maintained No Crayfish downstream of the WwTP due to appropriate treatment of the effluent therefore no adverse effects predicted. Sea Lamprey No Species not present within the potential zone of No influence of the discharge. Brook Lamprey Yes Good water quality status will be maintained No downstream of the WwTP due to appropriate treatment of the effluent therefore no adverse effects predicted. Salmon Yes Good water quality status will be maintained No downstream of the WwTP due to appropriate treatment of the effluent therefore no adverse effects predicted. Lesser Horseshoe No Species not present within the potential zone of No Bat influence of the discharge. Otter Yes Good water quality status will be maintained No downstream of the WwTP due to appropriate
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treatment of the effluent therefore no adverse effects predicted. Slender Green No Species not present within the potential zone of No Feather-moss influence of the discharge. Slender Naiad No Species not present within the potential zone of No influence of the discharge.
Mitigation Measures Milltown WwTP will be operational in 2016. The plant has sufficient capacity to effectively treat the wastewater from the agglomeration for current and future years and the quality of surface waters downstream of the plant are predicted to maintain Good water quality status. It is important that the effluent and downstream waters are continually monitored to ensure that the Surface Water Regulation limits are not breached downstream of the discharge point.
Once operational, to ensure satisfactory operation of the plant mitigation measures recommended are as follows: Ensure ELV’s set by the EPA are not breached; Continuation of monitoring of the discharge, including at the outfall, and the ambient background concentrations, on a consistent and regular basis; and Ensure that the Surface Water Regulation Good status limit values for BOD, Ammonia and Orthophosphate are not breached downstream as a result of the discharge by compliance with ELV’s set by EPA.
Stage 2 Appropriate Assessment Conclusion Statement The current Appropriate Assessment has been prepared following the EPA (2012) ‘Note on Appropriate Assessments for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007), Version 2.2’. The Department of the Environment, Heritage and Local Government guidance ‘Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities’ (2010) has also been taken into account. Therefore the current assessment for the Waste Water Discharge License investigates the potential adverse effects on the aquatic qualifying interests of the Natura 2000 network arising from the plant discharge, in combination with other plans / projects affecting the aquatic environment. The assessment considers whether the discharge, 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.
When the above mitigation measures are implemented in full, it is envisaged that there will be no significant adverse effects on the integrity of Lough Corrib SAC in view of the site’s conservation objectives and that the conservation status of the Annex I habitats and Annex II species will not be compromised by WwTP discharge either directly, indirectly or cumulatively.
It is therefore concluded that the Milltown WwTP discharge, alone or in-combination with other plans and / or projects will not give rise to significant effects on the integrity of Lough Corrib SAC, as long as the mitigation measures as listed above are implemented in full. Stage 2 concludes the Appropriate Assessment process of the Milltown Waste Discharge License.
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References
Demers, A. Lucey, J., McGarrigle, M. and Reynolds, J. (2005) The distribution of the white- clawed crayfish (Austropotamobius pallipes) in Ireland. Biology & Environment: 105B:65-69.
Environment Agency (2000). Aquatic Eutrophication in England & Wales: A Management Strategy. Environment Agency, Bristol.
EPA (2013) Report on river and lake water quality in Co. Galway 2013.
Haslam, S.M. (1978). River Plants. Cambridge University Press, Cambridge.
Hydro-G (2008) Assessment of the Potential Cumulative Impact on the Clare River, Co. Galway, of Wastewater Discharges from Wastewater Treatment Plants in Milltown, Tuam and Claregalway. Final Report. Prepared for Ryan Hanley Consulting Engineers. November 2008.
Kelly, F.L., Connor, L., Matson, R., Feeney, R., Morrissey, E., Coyne, J. and Rocks, K. (2015a) Sampling Fish for the Water Framework Directive, Rivers 2014. Inland Fisheries Ireland, 3044 Lake Drive, Citywest Business Campus, Dublin 24, Ireland.
Mainstone, C.P., Parr, W. & Day, M. (2000). Phosphorus and River Ecology – tackling sewage inputs. English Nature/Environment Agency, Peterborough.
NPWS (2013a) The Status of EU Protected Habitats and Species in Ireland. Habitats Assessments Volume 2, Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.
NPWS (2013b) The Status of EU Protected Habitats and Species in Ireland. Species Assessments Volume 3, Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.
NPWS (2013c) Lough Corrib SAC Site Synopsis Version date 19.08.2013
O’Connor, W. (2007) A Survey of Juvenile Lamprey Populations in the Corrib and Suir Catchments. Irish Wildlife Manuals No. 26. National Parks and Wildlife Service, Department of Environment, Heritage and Local Government, Dublin, Ireland.
OECD (1986) Water pollution by fertilisers and pesticides. Organisation for Economic Cooperation and Development, Paris, 144 pp.
Reynolds, J.D. (1998) Conservation management of the white-clawed crayfish, Austropotamobius pallipes. Part 1. Irish Wildlife Manuals, No. 1.
Routledge, E.J., D. Sheahan, C. Desbrow, G. Brighty, M. Waldock, and J.P. Sumpter (1998). Identification of estrogenic chemicals in sewage treatment effluent, 2. In vivo responses in trout and roach, Environment, Science and Technology, 32: 1559-65.
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Spink, A.J., Murphy, K.J., Smith, S.M. & Westlake DF (1993). Effects of eutrophication on Ranunculus and Potamogeton. Journal of Aquatic Plant Management 31, 113–117.
Tobin (2008) Appropriate Assessment Report, Proposed Wastewater Treatment Plant, Milltown, Co. Galway. Report for Galway County Council, May 2008. Prepared by Tobin Consulting Engineers and Ecofact Environmental Consultants.
WRBD(2010) Corrib Water Management Unit Action Plan http://wfdireland.ie/docs/1_River%20Basin%20Management%20Plans%202009%20- %202015/WRBD%20RBMP%202010/Water%20Management%20Unit%20Action%20Plans/Corri b%20WMU_190310.pdf
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