EcIA - Ecological Impact Assessment (EcIA) August 2020 County Donegal Towns & Villages Sewerage Schemes. Ramelton – Milford – Rathmullan (RMR) Sewerage Scheme 1 INTRODUCTION 1.1 Background Irish Water is proposing to upgrade the existing sewerage schemes in Ramelton, Milford and Rathmullan, Co. Donegal. These upgrade works include construction of main pumping stations with storm water storage and associated rising mains in Ramelton, Milford and Rathmullan and the construction of a new Ramelton-Milford-Rathmullan WwTP in the townland of Tirroddy, Ramelton. Woodrow Sustainable Solutions Ltd. (“Woodrow”) was commissioned by Irish Water to carry out an Ecological Impact Assessment (EcIA) of the proposed upgrade to the Ramelton-Milford-Rathmullan (RMR) Sewerage Scheme in Co. Donegal. The proposed RMR WwTP and associated infrastructure aims to bring waste water treatment benefits to Rathmullan, Milford and Ramelton and surrounding areas by ending the unacceptable practice of discharging untreated wastewater (from an outdated and over capacity system) into the Leannan Estuary, Lough Swilly and Maggy’s Burn. This includes creating a cleaner water environment than that of the current situation, which aims to enhance the areas' amenity value, particularly in Rathmullan, by contributing towards restoring the Blue Flag status of Rathmullan Beach. Through the intended water quality improvements, it is anticipated that overall water quality of the area will be significantly improved, in addition to the enhancement of water quality within a designated Salmonid Water, Maggy’s Burn, into which the existing over capacity Milford WwTP discharges (which then flows into Lough Fern, downstream of that site). The scheme will remove this overcapacity WwTP sewage discharge into Maggy’s Burn, diverting this instead to the proposed new RMR WwTP in Tirroddy. 1.2 Overview of Application and Requirements for Ecological Impact Assessment (EcIA) 1.2.1 Location of the Application Site It is proposed that a new Wastewater Treatment Plant (WwTP) shall be constructed at Tirroddy, Ramelton, Co. Donegal (National Grid Reference (NGR): C 24241 24489, ITM: 624190, 924497). This shall be connected to the proposed Milford Main Pumping Station (MPS) (NGR: C 19228 26495, ITM: 619177, 926502) via a 200mm Rising Main which will extend to a newly proposed Main Pumping Station at Ramelton (NGR: C 22933 21333, ITM: 622881, 921340) via a 200mm Rising Main proposed to cross the Leannan Estuary between Bridge End and Rossreagh. The Proposed RMR WwTP Site will also connect to two Proposed Pumping Stations (PS) at Rathmullan via 200mm Rising Main (Rathmullan PS No. 1 at NGR: C 29467 27453, ITM: 629415, 927460 and Rathmullan MPS No. 2 at NGR: C 29792 27565, ITM: 629740, 927572). The proposed new outfall pipeline for the RMR WwTP is planned to discharge into the Ramelton channel within the Leannan Estuary near Tirroddy Point (at approximate NGR: C 24601 23208, ITM: 624550, 923215). The scheme exists within and adjacent to the Lough Swilly Estuary, which is covered by two European Site Designations as a Special Area of Conservation (SAC) for habitats and species, and a Special Protection Area (SPA) for the protection of birds. Ramelton is a small rural town approximately 11km north of Letterkenny and approximately 7km south east of Milford on the western shores of Lough Swilly. The wastewater collection network in Ramelton is predominantly a combined system. The town’s core gravity collection network dates from the 1960s, and has been extended over the years to serve new residential developments. The newer extensions were designed to carry only foul water. There is currently no wastewater treatment plant (WwTP) in Ramelton. The wastewater collection network terminates in a 300mm trunk sewer, upstream of which is a ‘tank 1 EcIA - Ecological Impact Assessment (EcIA) August 2020 County Donegal Towns & Villages Sewerage Schemes. Ramelton – Milford – Rathmullan (RMR) Sewerage Scheme sewer’ (with dimensions of approximately 40m long x 1.6m wide and 1.9m high) from where unscreened and untreated wastewater discharges on an outgoing tide to the Ramelton channel in the Leannan estuary (at the mouth of the Leannan River), in Lough Swilly. There is one storm water overflow at the Mall that discharges unscreened and untreated wastewater into the tidal reaches of the River Leannan. Milford is a small rural town approximately 20km north of Letterkenny. The catchment is principally residential with no significant industrial presence. The wastewater collection network is predominantly a combined system. The existing Milford WwTP was commissioned in 1978. The existing plant is designed for a Dry Weather Flow of circa 230m3/d or 2.66l/s (based on an estimated design capacity of 920 p.e.). The Milford plant is significantly overloaded. Treated effluent from the WwTP discharges into Maggy's Burn. Rathmullan is a small seaside town on the Fanad Peninsula. It is situated on the western shore of Lough Swilly, approximately 22km to the northeast of Letterkenny. A sewerage network and two septic tanks currently serve the village of Rathmullan. Septic Tank No. 1 is located 80m west of Hill Head on the foreshore of the Upper Harbour, adjacent to the Main Street / Pound Street junction. Septic Tank No. 2 is located in Abbey View Housing Estate, 240m east of Hill Head and 50m from the foreshore of the Lower Harbour. Treated effluent from the septic tanks discharges into Lough Swilly via two outfalls. Preliminary Reports reviewing the sewer collection and treatment system in the towns of Ramelton, Milford and Rathmullan concluded that the lack of treatment of wastewater within the Ramelton catchment, Milford catchment and Rathmullan catchment is no longer satisfactory and in order to meet relevant statutory legislation, planning policies and environmental designations, appropriate treatment of the wastewater from these catchments is required. It is proposed that wastewater from the agglomerations of Ramelton, Milford and Rathmullan collectively be treated at a new plant in the townland of Tirroddy north, north east of Ramelton, with discharge of the treated effluent to an outfall in the Leannan Estuary (Source: Jennings O’Donovan). The area is characterised by undulating agricultural lands crisscrossed by valleys formed by streams and rivers rising in higher inland areas, flowing over rolling more fertile agricultural lands towards the silty coastal edge of Lough Swilly. Native and long-established woodland are evident throughout this landscape, including substantial wooded areas outside Ramelton, alongside the estuary at Brownknowe, and in addition, the National Parks and Wildlife Service (NPWS) own and manage a large woodland known as ‘Rathmullan Wood Nature Reserve’ situated alongside the R247 at Carraleena, Rathmullan. Isolated conifer plantations are sparingly located on higher lands within this area, one of which is now the proposed location for the RMR WwTP at Tirroddy. According to the Environmental Protection Agency (EPA) online mapping, the Application Site lies within an area of ‘Moderate’, ‘High’ and ‘Extreme’ GSI Vulnerability, with ‘rock at or near the surface’. This indicates parts of the area has a higher risk of potential groundwater contamination in the event of a pollution incident occurring. The aquifer at the Application Site is classified as “Pl – Poor Aquifer – Bedrock which is generally unproductive except for local zones)” according to the EPA1. This means that this site lies within an area that supports an “Aquifer with a limited and relatively poorly connected network of fractures, fissures and joints, giving a low fissure permeability which tends to decrease further with depth… Due to the low permeability and poor storage capacity, the aquifer has a low ‘recharge acceptance’. Some recharge in the upper, more fractured/weathered zone is likely to flow along the 1 Source: Environmental Protection Agency (EPA) Sewage Treatment Maps https://gis.epa.ie/EPAMaps/SewageTreatment?s=S (Accessed January 2020) 2 EcIA - Ecological Impact Assessment (EcIA) August 2020 County Donegal Towns & Villages Sewerage Schemes. Ramelton – Milford – Rathmullan (RMR) Sewerage Scheme relatively short flow paths and rapidly discharge to streams, small springs and seeps. Groundwater discharge to streams (‘baseflow’) can significantly decrease in the drier summer months. This aquifer is Similar to a ‘Locally Important Bedrock Aquifer, Moderately Productive only in Local Zones (Ll)’, but with fewer and more poorly-connected fractures, fissures and joints, and with less permeable and/or more limited zones of higher permeability. Overall permeability, storage capacity, recharge acceptance, length of flow path and baseflow are likely to be less than in Ll aquifers.”2 This indicates that the risk of potential contamination of surface water in the area is considered to be higher in the event of a pollution incident, given the hydrological environment here. 1.2.2 Description of the Proposed Development The proposed RMR Scheme is a major wastewater infrastructure scheme covering an extensive area between and including the three towns of Ramelton, Milford and Rathmullan. The Project Design Engineer for the scheme is Jennings O’Donovan (JOD). Works within the project footprint will be carried out within a number of different habitat types. The Rising Main works are largely confined within existing roads, apart from the significant in-estuary marine works to cross the Leannan Estuary in Lough Swilly and reach the proposed