Irish Water Report. Natura Impact Statement as part of the Riverstown Waste Water Certificate of Authorisation

Transcription

1 Irish Water Report Natura Impact Statement as part of the Riverstown Waste Water Certificate of Authorisation

2 Contents Introduction 4 Legislative Context 4 Methodology 6 Guidance Followed 6 Stages Involved in the Appropriate Assessment Process 7 Field Walkover Surveys 7 Consultation 7 Screening 8 Management of the Site 8 Description of the Project 8 Description of the Receiving Environment and Monitoring Results 8 Waste Assimilative Capacity 9 Field Walkover Survey 10 Brief Description of the Natura 2000 Sites 10 Possible Effects of the Waste Water Discharge in the Natura 2000 Sites 14 Direct, Indirect or Secondary Impacts 14 Possible Cumulative Impacts with other Plans and Projects in the Area 14 Screening Assessment 15 Likely Changes to the Natura 2000 Sites 17 Screening Conclusions 17 Stage 2: Appropriate Assessment 18 Description of the Natura 2000 Site Affected 18 Description of the Conservation Interests of the SAC 18 Annex I Habitats 18 Annex II Species 19 Conservation Objectives of the Unshin River SAC 20 Impact Prediction 20 Impacts on Water Quality 20 Impacts on Annex I Habitats 21 Impacts on Annex II Species 22 Mitigation Measures 23 Stage 2 Appropriate Assessment Conclusion Statement 24 2 Irish Water AA Screening - Riverstown

3 References 25 3 Irish Water AA Screening - Riverstown

4 Introduction This report provides an Appropriate Assessment (AA) of the existing Waste Water Treatment Plant (WwTP), located at Riverstown, approximately 15km south east of Sligo Town, for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007), as amended. It assesses whether the on-going 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). The AA was completed by a qualified ecologist, and full member of the CIEEM, on behalf of Irish Water. 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 through the establishment and conservation of an EU-wide network of sites known as Natura 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. 4 Irish Water NIS - Riverstown

5 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 for imperative reasons of overriding public, 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. 5 Irish Water NIS - Riverstown

6 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, 2009). 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, 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). 6 Irish Water NIS - Riverstown

7 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 during 13 th of May 2014 to identify the potential for qualifying species and habitats in the surrounding environs of the WwTP discharge. Consultation Consultation was undertaken with the Divisional Ecologist Northern Region of the National Parks and Wildlife Service, Mr. William Macoran, in relation to the existing discharge from the Riverstown WwTP. Concerns were identified regarding the existing plants discharge into the Unshin River SAC. 7 Irish Water NIS - Riverstown

8 Screening Management of the Site The Riverstown WwTP is not directly connected with or necessary to the management of the site for nature conservation. Description of the Project Riverstown is located about 15km South East of Sligo Town. The current population equivalent (residential & non domestic) served by the WwTW is approximately 462 p.e. The projected p.e. for 2021 is 468. Currently sewage from the village is conveyed via a combined collection network to the Waste Water Treatment Plant which is located to the west of the town. The plant is an extended aeration treatment plant and has a design p.e. of 600. The Riverstown agglomeration discharges in the Unshin River Special Area of Conservation (SAC). The WwTP consists of an inlet works, a primary settlement tank, aeration and clarifier, effluent outlet and a control room. There is a facility for Emergency Overflow prior to the inlet works. In the case of emergency (mechanical breakdown/power failure) this overflow is to the Unshin River at NGR E, N. Based on a p.e. of 462, the daily flow from the WwTP based on a 95% flow is 104m 3 /d. The daily flows within the receiving waters of the Unshin River based on the 95% flow is 12,096m 3 /d. This provides a significant dilution factor of 116.3:1 within the receiving watercourse. Description of the Receiving Environment and Monitoring Results The WwTP discharges to the Unshin River. Monitoring data from 2012/2013 from both upstream and downstream of the discharge locations demonstrates that the water quality within the Unshin River is in compliance with Schedule 5 of the European Communities Environmental Objectives (Surface Water) Regulations 2009 (S.I. No. 272 of 2009). Table 1.0: Monitoring Data both Upstream and Downstream of WwTP Discharge** Parameter EQS* Upstream Downstream BOD Ammonia (as NH 3 N) Orthophosphate *European Communities Environmental Objectives (Surface Waters) Regulations 2009, S.I. No. 272 of 2009 (95%ile standards presented). ** Data from 2012/2013 monitoring (averaged measured from 3 sampling occasions) In addition, the 2012 EPA Biological Water Quality monitoring data upstream of the discharge at Riverstown Bridge (Station 0200) was Q4 and the nearest monitoring point downstream (approx. 5.5 km) at Lisconny Bridge (Station 0400) was Q4. Further downstream at Ballygrania Bridge (Station 0500) the Q value was 4-5. This 2012 data indicates Good Status water both upstream and downstream of the WwTP discharge. 8 Irish Water NIS - Riverstown

9 Waste Assimilative Capacity Table 2.0a summaries the assimilative capacity calculations which are based on the 2021 estimated loading of 468p.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 have been carried out for the actual background concentrations and the notionally clean river approach and the WWTP effluent design standards. Table 2.0a: Assimilative capacity calculations at estimated 2021 loadings of 468p.e. for actual background concentrations and for a notionally clean river using effluent design standards. Parameter Background Predicted EQS* (mg/l) (mg/l) downstream quality (mg/l) BOD Actual Background Notionally Clean Ammonia Actual Background Notionally Clean Orthophosphate Actual Background Notionally Clean *European Communities Environmental Objectives (Surface Waters) Regulations 2009, S.I. No. 272 of 2009 (95%ile standards presented). Assuming notionally clean water in the Unshin River, the receiving water does not have adequate waste assimilative capacity for the Riverstown WwTP, specifically, for Ammonia. The WAC was also carried out using the mean discharge concentration for Ammonia for 2015 (i.e. current situation). This mean value is based on 10 sampling dates. Based on this calculation it would suggest that the Unshin River has available assimilative capacity to accommodate the WwTP discharge in terms of Ammonia using both the actually background concentration and the EPA notionally clean river concentration (see Table 2.0b). Table 2.0b: Assimilative capacity calculations at estimated 2021 loadings of 468p.e. for the actual background concentration and for a notionally clean river using the 2015 mean effluent concentration for Ammonia (based on 10 sampling dates). Parameter Background (mg/l) Predicted downstream EQS* (mg/l) quality (mg/l) Ammonia Actual Background Notionally Clean *European Communities Environmental Objectives (Surface Waters) Regulations 2009, S.I. No. 272 of 2009 (95%ile standards presented). 9 Irish Water NIS - Riverstown

10 It appears that the current operation of the Riverstown WwTP and associated discharge to the Unshin River is not noticeably affecting biological water quality. Likewise, the impact of the current discharge on the chemical water quality is not considered to be significant. Field Walkover Survey At the existing discharge location the Unshin River contained a riffle / glide / pool habitat type, with a greater proportion of the riffle habitat upstream of the discharge location. It has a good flow with a substratum type of boulders, cobbles, gravel and sand. Water depth 0.2 1m+. Instream vegetation consisted of a good distribution of Water-crowfoot (Ranunculus spp.) both upstream and downstream of the discharge location. Immediately downstream of the discharge location emergent macrophytes (e.g. Typha latifolia, Phalaris arundinaceae) were evident, together with filamentus algae (Cladophora spp.), which are indicative of nutrient enrichment. Field examination, including both upstream and downstream of the discharge location, revealed the presence of the Annex I habitat: Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho- Batrachion vegetation [3260]. And the Annex II Species: Salmon (Salmo salar) [1106]; and Otter (Lutra lutra) [1355]. The Unshin and its tributaries is the most important salmon producing river in Co. Sligo. The system also supports a good population of trout. Suitable spawning ground was located along this stretch, both upstream and downstream of the discharge location. There was a greater proportion of spawning grounds upstream of the discharge location, however, suitable spawning and resting pools were also recorded downstream of the discharge location. In addition, juvenile salmonids were observed throughout the downstream section, approximately 500m below the discharge location, together with suitable nursery and adult habitats. Otter are widespread throughout the Unshin River catchment, and otter signs were also recorded downstream of the discharge location. This watercourse was the subject of recent flooding, and so further signs of otters (e.g. spraints, feeding remains, paths/slides) could have been recently washed away. Brief Description of the Natura 2000 Sites This section of the screening process describes the Natura 2000 sites within a 15km radius of the WwTP discharge location. A 15km buffer zone has been chosen as a precautionary measure, to ensure that all potentially affected Natura 2000 sites are included in the screening process, which is in line with Appropriate Assessment of Plans and Projects in Ireland Guidance for Planning Authorities produced by the Department of the Environment, Heritage and Local Government. 10 Irish Water NIS - Riverstown

11 Table 3.0 list the SACs and Table 4.0 lists the SPAs that are within 15km of the WwTP discharge location, and Figure 1.0 shows their location in relation to the Riverstown WwTP discharge. The qualifying s of each of the identified Natura 2000 Sites is also provided. Table 3.0: SACs located within 15km from Riverstown WwTP discharge Site Code Site Name Qualifying Habitats Qualify Species Templehouse and Cloonacleigha Loughs SAC Bricklieve Mountains & Keishcorran SAC Hard oligo-mesotrophic waters with - benthic vegetation of Chara spp. [3140]; and Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation [3260]. Turloughs [3180]; Semi-natural dry grasslands and scrubland facies on calcareous substrates (Festuco Brometalia)(*important orchid sites) [1092]. [6210]; Marsh fritillary (Euphydryas aurinia) [1065]; and White-clawed crayfish (Austropotamobius pallipes) Lowland hay meadows (Alopecurus pratensis, Sanguisorba officinalis) [6510]; and Calcareous and calcshist screes of the montane to alpine levels (Thlaspietea rotundifolii) [8120] Lough Arrow SAC Hard oligo-mesotrophic waters with - benthic vegetation of Chara spp. [3140] Unshin River SAC Water courses of plain to montane Salmon (Salmo salar) [1106]; levels with the Ranunculion fluitantis and and Callitricho-Batrachion vegetation Otter (Lutra lutra) [1355]. [3260]; and Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) [91E0] Ballysadare Bay Estuaries [1130]; Marsh Snail (Vertigo SAC Mudflats and sandflats not covered by angustior) [1014]; and seawater at low tide [1140]; Harbour seal (Phoca vitulina) Embryonic shifting dunes [2110]; [1365]. Shifting dunes along the shoreline with Ammophila arenaria (white dunes) [2120]; Fixed coastal dunes with herbaceous vegetation (grey dunes) [2130]; and Humid dune slacks [2190] Lough Gill SAC Natural euthrophic lakes with White-clawed crayfish 11 Irish Water NIS - Riverstown

12 Site Code Site Name Qualifying Habitats Qualify Species Magnopotamion or Hydrocharition-type vegetation [3150]; Old sessile oak woods with Ilex and Blechnum in British Isles [91A0]; and Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) [91E0] Union Wood SAC Old sessile oak woods with Ilex and Blechnum in British Isles [91A0]. (Austropotamobius pallipes) [1092]; Sea lamprey (Petromyzon marinus) [1095]; Brook lamprey (Lampetra planeri) [1096]; River lamprey (Lampetra fluviatilis) [1099]; Salmon (Salmo salar) [1106]; and Otter (Lutra lutra) [1355]. - Table 4.0: SPAs located within 15km from Riverstown WwTP discharge Site Code Site Name Qualifying Features Annex I Species Ballysadare Bay SPA Light-bellied Brent Goose (Branta bernicla hrota) [A046]; Grey Plover (Pluvialis squatarola) [A141]; Dunlin (Calidris alpina) [A149]; Bar-tailed Godwit (Limosa lapponica) [A157]; Redshank (Tringa totanus) [A162]; and Wetlands & Waterbirds [A999] Lough Arrow SPA Little Grebe (Tachybaptus ruficollis) [A004]; Tufted Duck (Aythya fuligula) [A061]; and Wetlands & Waterbirds [A999]. 12 Irish Water NIS - Riverstown

13 13 Irish Water NIS - Riverstown

14 Possible Effects of the Waste Water Discharge in the Natura 2000 Sites The purpose of this section of the screening is to examine the possibility that the waste water discharge, either individually or in combination with other plans and projects, may result in significant negative effects on the Conservation Objectives and the integrity of the Natura 2000 Sites identified. The most apparent potential risk to a Natura 2000 Site(s) from a WwTP discharge is to the water quality of the receiving environment, and if the receiving environments water quality has the potential to interact with the qualifying s of the Natura 2000 Sites identified. The WwTP discharges to the Unshin River, which is itself designated as part of the Unshin River SAC. Direct, Indirect or Secondary Impacts The Riverstown WwTP discharges directly to the Unshin River SAC. The receiving waters of the SAC does not have sufficient assimilative capacity for the effluent in terms of Ammonia, based on the effluent design standard for Ammonia. However, based on the 2015 mean effluent concentration (based on 10 samples), the receiving water has sufficient assimilative capacity for the effluent in terms of Ammonia. The upstream and downstream monitoring results demonstrate that the Unshin River water quality is in compliance with Schedule 5 of the Surface Water Regulations and does not appear to be impacted by the WwTP discharge. Likewise, the 2012 EPA Biological Water Quality data shows that the current biological water quality both upstream (immediately upstream of the discharge location at Station Riverstown Bridge) and downstream at Station Lisconny Bridge is Q 4, which indicates Good Status water both upstream and downstream of the WwTP discharge. However, immediately downstream of the discharge location emergent macrophytes (e.g. Typha latifolia, Phalaris arundinaceae) were evident, together with filamentus algae (Cladophora spp.), which are indicative of nutrient enrichment. Elevated nutrient levels in the Unshin River is considered to be a significant threat to the integrity and favourable conservation status of the SAC and the Annex II species for which it is designated. Possible Cumulative Impacts with other Plans and Projects in the Area As part of Stage 1 Screening, in addition to the proposed waste water discharge, other relevant projects and plans in the relevant region must also be considered. This step aims to identify at this early stage any possible significant effects on the Natura 2000 Sites from the waste water discharge in-combination or cumulative with other plans and projects. Existing plans and projects which have been examined include: Sligo County Development Plan ; Western River Basin Management Plan ; Owenmore Water Management Unit Action Plan; Biodiversity Action Plan ; and Existing Riverstown Wastewater Treatment Plant. 14 Irish Water NIS - Riverstown

15 The above plans have been assessed in accordance with Article 6(3) of the Habitats Directive and Part XAB of the Planning and Development Act, 2000, and are not envisaged to result in significant effects on the integrity of the Natura 2000 network. The upstream and downstream monitoring results indicates that the Unshin River is already being impacted prior to the WwTP discharge. The likely source of this impact is diffuse pollution from agricultural runoff. The discharge from Riverstown WwTP exceeds the maximum assimilation capacity for Ammonia at 95%ile flows based on the design effluent standard for Ammonia. However, using the mean concentration for 2015 it would suggest that there is assimilative capacity in Unshin River for Ammonia. Despite the above as noted previously downstream of the discharge location emergent macrophytes (e.g. Typha latifolia, Phalaris arundinaceae) were evident, together with filamentus algae (Cladophora spp.), which are indicative of nutrient enrichment. Elevated nutrient levels in the Unshin River is considered to be a significant threat to the integrity and favourable conservation status of the SAC and the Annex II species for which it is designated. Therefore, based on this assessment and taking the pre-cautionary principle approach it must be considered that the discharge is potentially causing significant cumulative effects on the water dependent qualifying s of the Unshin River SAC. In accordance with the Waste Water Discharge (Authorisation) Regulations 2007 (S.I. No. 684 of 2007) the waste water discharged from Riverstown WwTP is potentially impacting on the water quality of the Unshin River, and therefore, is potentially impacting on the conservation objectives of the Unshin River SAC. Potentially significant adverse impacts on the water dependent qualifying habitats (Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation) and species (Salmon (Salmo salar) and Otter (Lutra lutra)) of the Unshin River SAC are anticipated as a result of the waste water discharge from Riverstown WwTP. No significant adverse impacts on the qualifying s of the remaining Natura 2000 Sites identified within 15km of the discharge location is considered likely due to the distance between the discharge location and the relevant SACs or SPAs. Screening Assessment Table 5.0 provides a summary of the likely significant impact of the waste water discharge on the conservation objectives of the identified Natura 2000 site in Tables 3.0 and Irish Water NIS - Riverstown

16 Table 5.0: Potential Significant Impacts on Natura 2000 sites from the Riverstown Waste Water Discharge Site Name Direct Impacts Indirect/ Secondary Templehouse and Cloonacleigha Loughs SAC Bricklieve Mountains & Keishcorran SAC Lough Arrow SAC Unshin River SAC Ballysadare Bay SAC Lough Gill SAC Union Wood SAC Ballysadare Bay SPA Lough Arrow SPA qualifying qualifying qualifying Potential impact on the water quality of the Unshin River as a result of the WwTP discharge qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying Potential impact on the water quality of the Unshin River as a result of the WwTP discharge qualifying qualifying qualifying qualifying qualifying Resource Requirements (Drinking Water Abstraction Etc.) qualifying qualifying qualifying qualifying qualifying qualifying Emissions (Disposal to Land, Water or Air) qualifying qualifying qualifying Potential impact on the water quality of the Unshin River as a result of the WwTP discharge qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying Excavation Requirements qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying Transportation Requirements qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying Duration of Construction, Operation, Decommissioning qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying qualifying 16 Irish Water NIS - Riverstown

17 Likely Changes to the Natura 2000 Sites The likely changes that will arise from the Riverstown WwTP discharge have been examined in the context of a number of factors that could potentially affect the integrity of the identified Natura 2000 sites (see Table 6.0). Table 6.0: Potential Significant Impacts on Natura 2000 sites from the Riverstown Waste Water Discharge Site Name Templehouse and Cloonacleigha Loughs SAC Bricklieve Mountains & Keishcorran SAC Reduction of Habitat Area Disturbance to Key Species Habitat or Species Fragmentation Reduction in Species Density Changes in Key Indicators of Conservation Value (Water Quality Etc.) Climate Change None None None None None None None None None None None None Lough Arrow SAC None None None None None None Unshin River SAC Ballysadare Bay SAC Potential negative impact Potential negative impact Potential negative impact Potential negative impact Potential negative impact None None None None None None None Lough Gill SAC None None None None None None Union Wood SAC None None None None None None Ballysadare Bay SPA None None None None None None Lough Arrow SPA None None None None None None Screening Conclusions From the current screening assessment, taking account of supporting documentation, there is the potential for on-going significant cumulative impacts affecting the Unshin River SAC arising from the operation of the Riverstown WwTP. From the examination of the information available it is considered that the discharge has the potential to result in significant impacts to the Natura 2000 network, specifically in relation to direct and cumulative impacts affecting the conservation s of the Unshin River SAC. On the basis of the findings of this Screening for Appropriate Assessment, it is concluded that the current Riverstown WwTP discharge to the Unshin River: (i) (ii) is not directly connected with or necessary to the management of a Natura 2000 site; and may have significant effects on a Natura 2000 site, the Unshin River SAC. Therefore, applying the Precautionary Principle and in accordance with Article 6(3) of the Habitats Directive, the current WwTP discharge at Riverstown will be brought forward for a Stage 2 Appropriate Assessment. 17 Irish Water NIS - Riverstown

18 Stage 2: Appropriate Assessment In this section, the Unshin River SAC, which has been determined as requiring AA, is described and all the potential impacts resulting from the Riverstown WwTP discharge are discussed in relation to the conservation objectives of this designated site. Description of the Natura 2000 Site Affected The Unshin River runs from Lough Arrow north to Ballysadare Bay, Co. Sligo. This site consists of a pristine unmanaged, undrained river and its marginal vegetation. Other rivers included within the site are the Owenboy/Owenbeg and a number of smaller tributaries. The site is a candidate SAC selected for alluvial wet woodlands, a priority habitat on Annex I of the E.U. Habitats Directive, and for floating river vegetation, also listed on Annex I of the E.U. Habitats Directive. The site is also selected for the following species listed on Annex II of the same directive Atlantic Salmon and Otter. The Unshin River flows across a number of geological boundaries between sandstone, shales and limestone. This results in unusual physio-chemical qualities which in turn are reflected in the rich and varied plant and animal populations. The diversity of aquatic macrophytes is exceptional and to an extent the unusual combinations and richness of species can be accounted for by the good quality water being discharged from Lough Arrow upstream. The Unshin and its tributaries form a very important system for Atlantic Salmon, a species that is listed on Annex II of the E.U. Habitats Directive. The Owenboy/Owenbeg River is the principle spawning and nursery tributary for the system s salmon fishery. The Unshin and its tributaries is the most important salmon producing river in Co. Sligo. The system also supports a good population of trout. Two notable bird species which occur along the river are Whooper Swan, which feeds in the wet grasslands that flank the river, and Kingfisher. Both are listed on Annex I of the E.U. Birds Directive. The trophic status of the river increases downstream indicating that some enrichment is taking place, however, the quality of the Unshin River and particularly its aquatic macrophyte communities make it rare in both an Irish and European context. Description of the Conservation Interests of the SAC Annex I Habitats The Unshin River SAC contains two Annex I habitats: Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) [91E0]; a priority habitat; and Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho- Batrachion vegetation [3260]. Of these habitats, the Riverstown WwTP discharge is assessed as having the potential to impact on floating river vegetation (Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation) only, as this habitat is dependent on water 18 Irish Water NIS - Riverstown

19 quality. Water quality does not threaten alluvial forests to the same degree, with little/no potential for adverse effects, and no changes to the conservation status of this habitat. 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. Floating mats of these white-flowered species are characteristic of river channels in early to mid-summer. They may modify water flow, promote fine sediment deposition, and provide shelter and food for fish and invertebrate animals. The habitat type 'Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation' is present along the stretch of the Unshin River into which the Riverstown WwTP discharges. Annex II Species The Unshin River SAC is very important for the presence of a number of scarce and specialised Annex II animal species, with particularly important population of Atlantic Salmon (Salmo salar). Atlantic Salmon (1106) The Unshin and its tributaries is the most important salmon producing river in Co. Sligo. The Owenboy/Owenbeg river is the principle spawning and nursery tributary for the system s salmon fishery. The system also supports a good population of trout. Suitable physical habitat for salmon spawning and early life stages of salmon occurs in the Unshin River both upstream and downstream of the WwTP outfall with the occurrence of glides, riffled and pool habitats present. The conservation status of salmon in the Unshin River is dependent on good water quality status; as this species requires clean water (Q4) for spawning and early life stages. This species is evaluated as being of overall 'Bad' conservation status nationally (NPWS 2013b). Otter (1355) Otter is widespread in the Unshin River SAC. 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. Otter is likely to occur in the Unshin River at Riverstown. One otter holt was recorded during the current survey. The overall assessment of the conservation status of otter is 'Favourable' (NPWS, 2013b). 19 Irish Water NIS - Riverstown

20 Conservation Objectives of the Unshin River SAC 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 s. Qualifying s 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. The conservations objectives for the Unshin River SAC are set out below: 1. To maintain or restore the favourable conservation condition of the Annex I habitats and/or Annex II species for which the SAC has been selected: Salmon (Salmo salar) [1106]; Otter (Lutra lutra) [1355]; Impact Prediction Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation [3260]; and Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) [91E0]. Impacts on Water Quality The aquatic conservation s of the Unshin River SAC are directly dependant on the aquatic environment and as the Riverstown WwTP discharges to the Unshin River within the SAC designation, there is a connection between this facility and the ecological receptors in the Unshin River. Elevated nutrient levels in the Unshin River, specifically Ammonia, Nitrates, Orthophosphates, and also Suspended Solids are considered to be the most significant threats to the integrity and favourable conservation status of the SAC and the Annex II species for which it is designated. The 2012 EPA Biological Water Quality data shows that the current biological water quality both upstream (immediately upstream of the discharge location at Station Riverstown Bridge) and downstream (approximately 5.2km) at Station Lisconny Bridge) is Q 4, which indicates Good Status water both upstream and downstream of the WwTP discharge. The 2012/13 upstream and downstream monitoring results demonstrate that the Unshin River water quality is in compliance with Schedule 5 of the Surface Water Regulations and does not appear to be impacted by the WwTP discharge. 20 Irish Water NIS - Riverstown

21 Assuming notional clean water in the Unshin River, the receiving water does not have adequate waste assimilative capacity based on the design standard for Ammonia. However, the Unshin River has available assimilative capacity to accommodate the WwTP discharge in terms of the current mean Ammonia concentration (based on 10 samples in 2015) using both the actually background concentration and the EPA notionally clean river concentration. It appears that the operation of the Riverstown WwTP and associated discharge to the Unshin River is not noticeably affecting biological water quality. Likewise, the impact of the discharge on chemical water quality is not considered to be significant. Cumulative impacts in the catchment possibly pose the greatest risk to the conservation objectives. The potential threat(s) of the Riverstown WwTP on water quality (long term or single event) is greatly increased when taken in combination with other water quality concerns in the catchment. For example the Collooney WwTP which discharges to the Unshin River also affects water quality. Other impacts which are likely to act cumulatively and impact on the SAC result from the following: Chemical fertiliser application to agricultural lands (the main fertilisers in use supply nitrogen, phosphorus, potassium and sulphur); 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; On-site wastewater treatment systems, poorly performing septic tank units and other small effluent systems can be significant sources of nutrients to rivers; Water abstraction from rivers can cause low flows, which can be directly damaging due to reducing flows and assimilation capacity; Point pressures including Section 4 licenced facilities and IPPC licenced facilities; Quarries - there are 3 quarries in the Owenmore WMU. Impacts on Annex I Habitats Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho- Batrachion vegetation [3260] Water quality (particularly phosphorus and nitrates) strongly influences the species composition, extent and condition of riverine plant communities. The key parameters include alkalinity, ph, 21 Irish Water NIS - Riverstown

22 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 nutrient increases lead to an overall impoverishment of the plant community, with algae dominating. It is considered that the ongoing operation of the Riverstown WwTP plant is contributing to background quality pressures in the Unshin River. The Unshin River is particularly vulnerable to water pollution, that is derived from domestic sources and from agricultural activities posing the greatest threat. According to NPWS (2008), discharges, fertilisation and water pollution are identified as the main pressures affecting floating river vegetation habitat. This has implications for the existing WwTP at Riverstown, which is contributing to cumulative impacts on background water quality in the Unshin River. It is considered however that the ongoing operation of the Riverstown plant would have imperceptible localised impacts in this habitat. Impacts on Annex II Species Atlantic Salmon (1106) Poor water quality will affect the conservation status of salmon in the Unshin River, as this species requires clean water (Q4) for spawning and early life stages. The Riverstown WwTP is considered to be contributing to water quality problems in the Unshin River, but the cumulative effect of the discharge on water quality is considered insignificant. In this light, the Riverstown WwTP is affecting the potential of the Unshin River as a salmon producing watercourse at a limited localised level at most. Overall, the conservation status of salmon in the Unshin River SAC is not thought to be affected by the Riverstown plant discharge as this species has a wide range in the catchment and impacts from the plant would be localised only. The Unshin and its tributaries is the most important salmon producing river in Co. Sligo. The Owenboy/Owenbeg River is the principle spawning and nursery tributary for the system s salmon fishery. Suitable physical habitat for salmon spawning and early life stages of salmon occurs in the Unshin River downstream of the WwTP outfall with the occurrence of glides, riffled and pool habitats present. The conservation status of salmon in the Unshin River is dependent on good water quality status; as this species requires clean water (Q4) for spawning and early life stages. This species is evaluated as being of overall 'Bad' conservation status nationally (NPWS 2013b). 22 Irish Water NIS - Riverstown

23 Otter (1355) Reduced water quality and ecological status downstream of the discharge of the Riverstown WwTP could be potentially having indirect effects on otters; as a result of reduced food supply i.e. reduced macroinvertebrate and fisheries production. The otter is dependent on fish stocks, which are ultimately dependent on water quality. However, there is no indication that the ongoing operation of this plant is having an adverse effect on otters within the Unshin River SAC as a whole. Mitigation Measures The current population equivalent (2015) served by the WwTP is approximately 362 p.e., and the design of the plant is 600 p.e. Assuming notionally clean water in the Unshin River the receiving water does not have adequate waste assimilative capacity for the WWTP design standard for Ammonia. However based on the current situation (mean 2015 concentration), it would suggest that the Unshin River has available assimilative capacity to accommodate the WwTP discharge in terms of Ammonia using both the actually background concentrations and the EPA notionally clean river concentration. However, immediately downstream of the discharge location emergent macrophytes (e.g. Typha latifolia, Phalaris arundinaceae) were evident during a walkover survey, together with filamentus algae (Cladophora spp.), which are indicative of nutrient enrichment. However, based on the impact assessment above it is considered that current operation of the Riverstown plant is having imperceptible localised impacts on the SACs qualifying habitats and that the conservation status of qualifying species in the Unshin River SAC are not thought to be affected by the Riverstown plant discharge. For the above situation to continue it is recommended that the following mitigation measures are implemented: Implementation of an appropriate performance management system for the plant in accordance with the Owenmore Water Management Unit Action Plan; and Continuation of monitoring of the discharge, both upstream and downstream of the plant. Annual biological water quality monitoring should also be undertaken upstream and downstream of the WwTP outfall. Any biological monitoring should be carried out during the summer / autumn periods. 23 Irish Water NIS - Riverstown

24 Stage 2 Appropriate Assessment Conclusion Statement The current Appropriate Assessment has been prepared following the EPA (2009) Note on Appropriate Assessments for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007). The Department of the Environment, Heritage and Local Government guidance Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities (DoEHLG, 2009a) has also been taken into account. Therefore, the current assessment for the Waste Water Certificate of Authorisation investigates the potential adverse effects on the aquatic qualifying s 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 the Unshin River 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 the Riverstown WwTP discharge either directly, indirectly or cumulatively. It is therefore concluded that the Riverstown WwTP discharge, alone or in-combination with other plans and / or projects will not give rise to significant effects on the integrity of the Unshin River SAC, as long as the mitigation measures as listed above are implemented in full. Stage 2 concludes the Appropriate Assessment process of the Riverstown Waste Water Certificate of Authorisation. 24 Irish Water NIS - Riverstown

25 References DoEHLG (2008). Circular L8/08 Water Services Investment and Rural Water Programmes Protection of Natural Heritage and National Monuments. Department of the Environment, Heritage and Local Government. DoEHLG (2009). Appropriate Assessment of Plans and Projects in Ireland. Guidance for Planning Authorities. Department of the Environment, Heritage and Local Government. Environment Agency (2000). Aquatic Eutrophication in England & Wales: A Management Strategy. Environment Agency, Bristol. European Commission (2000a). Communication from the Commission on the Precautionary Principle., Office for Official Publications of the European Communities, Luxembourg. European Commission (2000b). 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. European Commission (2001). 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. European Commission (2006). Nature and biodiversity cases: Ruling of the European Court of Justice. Office for Official Publications of the European Communities, Luxembourg. European Commission (2007). 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, compensatory measures, overall coherence, opinion of the commission. European Commission (2013). Interpretation Manual of European Union Habitats. Version EUR 28. DG Environment. European Communities Environmental Objectives (Surface Waters) Regulations S.I. 272 of European Communities (Birds and Natural Habitats) Regulations S.I. 477 of EPA (2009) Waste Water Discharge Licensing Appropriate Assessment Guidance Notes. Notes on Appropriate Assessments for the purposes of the Waste Water Discharge (Authorisation) Regulations, 2007 (S.I. No. 684 of 2007) Environmental Protection Agency, Co. Wexford. EPA (2014). EPA Maps, accessed 21/05/2014: 25 Irish Water NIS - Riverstown