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HomeMy WebLinkAbout2660018 - F.I. Received Doc. - Hydrolgical & Hydrogeological responses___________________________________________________________________________________________________ 1 Date: 26th May 2026 Our Ref: P1758-0_0010 Monaghan County Council, Planning Offices, Monaghan County Council, 1 Dublin Street, Monaghan, H18 X982. To whom it may concern, Re: Request for Further Information Hydrological and Hydrogeological Responses to Monaghan County Council Further Information Request Items relating to the proposed Renewable Biogas Plant and associated road improvements, on a site of approximately 6.2 hectares located immediately west of the R189 Road and south of the L2280 Road, on lands in the townlands of Maghernakelly and Drumcall, Co. Monaghan. MCC Planning Ref: P26/60018 ___________________________________________________________________________________________ Hydro-Environmental Services (HES) were requested by Stream BioEnergy Ireland Limited to respond to the hydrological and hydrogeological Further Information Request (FIR) Items raised in Monaghan County Council’s (MCC) letter dated 24th March 2026. This FIR response letter responds to Item 2 (c) of the MCC letter. Please note that as part of further consultation with M CC, Stream BioEnergy Ireland Ltd proposes to remove the Soil Relocation Area from the Proposed Development. Therefore, this response is made in that context, and presents a hydrological and hydrogeology assessment of the potential for the remainder of the Proposed Development to impact on local hydrology/hydrogeology and wetland areas. 1 STATEMENT OF EXPERIENCE Hydro-Environmental Services (HES) are a specialist geological, hydrological, hydrogeological and environmental practice that delivers a range of water and environmental management consultancy services to the private and public sectors across Ireland and Northern Ireland. HES was established in 2005, and our office is located in Dungarvan, County Waterford. We routinely complete impact assessments for hydrology and hydrogeology for a large variety of project types. This RFI response was prepared by Conor McGettigan and Michael Gill. Conor McGettigan (BSc, MSc) is an Environmental Scientist with over 5 years in the environmental sector in Ireland. Conor holds an M.Sc. in Applied Environmental Science (2020) from University College Dublin. Conor has also completed a B.Sc. in Geology (20 16) from University College Dublin. Conor routinely prepares hydrological and hydrogeological impact assessments for a wide variety of developments on peatlands including work on over 20 wind farm projects, as well as residential, commercial and industrial developments. Michael Gill (BA, BAI, Dip Geol., MSc, MIEI) is an Environmental Engineer and Hydrogeologist with over 24 years’ environmental consultancy experience in Ireland. Michael has completed numerous hydrological and hydrogeological impact assessments for a variety of development RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 2 types across Ireland. He has substantial experience in surface water drainage design and S uDS design, surface water/groundwater interactions, and specialises in wetland and peatland eco- hydrology. 2 FURTHER INFORMATION RESPONSE 2.1 ITEM 2 (C) Item 2 (c) reads as follows: “In the interests of environmental protection, the applicant is requested to provide the following information………. (c) A hydrogeological risk assessment to demonstrate how the hydrological balance of surrounding, higher-quality intact bog areas may, or may not be affected. The submitted assessment shall have particular regard to areas of cutover peat at the soil relocation site.” HES Response: A desk study of the Proposed Development site and the surrounding area was completed by HES to inform the response. This involved collecting all relevant geological, hydrological and hydrogeological data for the area. This included consultation with the following: • Environmental Protection Agency Database (www.epa.ie); • Geological Survey of Ireland - Groundwater Database (www.gsi.ie); • National Parks & Wildlife Services Public Map Viewer (www.npws.ie); • Water Framework Directive “Catchments” Map Viewer (www.catchments.ie); • Bedrock Geology 1:100,000 scale map series, Geological Survey of Ireland (GSI, 1995); • Geological Survey of Ireland – Groundwater Body Initial Characterisation Reports; • Map of Irish Wetlands (https://wetland.maps.arcgis.com); and, • The submitted Environmental Impact Assessment Report (MCC Planning Ref: 26/60018). Table A below presents a summary of the environmental conditions at the Proposed Development site and the surrounding area: Table A: Summary Desk Study Information Physical Feature Details Site Description and Topography The Proposed Development site is located ~4 km northwest of Cootehill, Co. Cavan and 17.5 km southwest of Monaghan Town. The Proposed Development site is located in the townland of Maghernakelly and covers an area of ~8.84 ha. The Proposed Development site is dissected by the R189 regional road which joins Cootehill in the south and Newbliss in the north. The Proposed Renewable Biogas Plant Site (~6.2 ha) is located to the west of this regional road whilst the Soil Relocation Area (~2.7 ha) is located to the east (note that it is no longer proposed to store soil in this area). The Renewable Biogas Plant Site is also located to the south of the L2280 Drumcall Road, with the former proposed Soil Relocation Area located to the west of the L2320 Drumgole Road. According to Corine landcover mapping (2018) the Proposed Development site is located in an area of agricultural pastures. This correlates with the details provided in the EIAR which describes the Renewable Biogas Plant Site as comprising of two fields which are divided by tree lined hedgerows and the former proposed Soil Relocation Area which is described as an area of improved grassland under active pastoral use. Based on map contours (www.gsi.ie) the topography at the Proposed Development site slopes from south to north. Topography at the Renewable Biogas Plant Site ranges from ~109 mOD (metres above Ordnance Datum) in the south to ~93 mOD in the north. RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 3 Historical mapping The local 25” and 6” base maps for the local area were reviewed. The base mapping names the former proposed Soil Relocation Area as “Black Kesh”. It is noted that historically kesh refers to rough or boggy ground. Short scattered tuft marks (possibly reeds) are also present in the north of the former proposed Soil Relocation Area indicating rough pasture. Geology The published Teagasc soils map (www.gsi.ie) shows that the Proposed Development site is predominantly overlain by mainly acidic, poorly drained mineral soils (AminPD) with some areas in the north and northeast overlain by cutover/cutaway peat. The GSI subsoils map (www.gsi.ie) shows that the Proposed Development site is underlain predominantly by till derived from Lower Palaeozoic sandstones and shales. Some areas in the north are underlain by cutover raised peat whilst some mineral alluvium is also mapped to the southeast of the Soil Relocation Area. The GSI bedrock geology map shows that the Proposed Development site is underlain by the Red Island Formation which comprises of greywacke, microconglomerate and argillite. The GSI does not map the presence of any bedrock outcrop within the local area. Surface Water Hydrology Regionally, the Proposed Development site is located in the Erne surface water catchment within Hydrometric Area 36. More locally, the Proposed Development site is mapped in the Dromore_SC_020 sub-catchment and the Dromore_070 WFD river sub-basin. There are no EPA mapped watercourses within the Proposed Development site. The closest mapped watercourse is the Coolkill Lough Stream (EPA Code: 36C12) located ~350m northeast of the proposed biogas plant site. This stream discharges into Coolkill Lough to the ~2.8 km east/northeast. The Rockcorry Stream outfalls from Coolkill Lough and flows to the north before veering to the west and flowing into Drumgole Lough. Surface Water Flows There are no OPW gauging stations in the vicinity of the Proposed Development site (www.catchments.ie). Surface Water Quality There are no EPA Biological Q-rating monitoring stations in the vicinity of the Proposed Development site. The closest downstream monitoring station is located on the Dromore River to the north of Cootehill where the river achieved a Q3 rating (poor) in 2025. Hydrogeology The Proposed Development site is mapped to be underlain by a Poor Aquifer – Bedrock which is Generally Unproductive except for Local Zones. The Proposed Development site is mapped to be underlain by the Cavan Groundwater Body (GWB) which is characterised by poorly productive bedrock (www.gsi.ie). Groundwater vulnerability at the Proposed Development site is mapped as low. Groundwater recharge at the Proposed Development site is estimated to be ~4-8% (www.gsi.ie). The GSI estimated recharge rates are based on low permeability subsoils. Designated Sites There are no SACs or SPAs in close proximity or immediately downstream of the Proposed Development site. The Drumgole Lough pNHA (001601) is located ~870m north of the Proposed Development site. The length of the hydrological flowpath between the site and the pNHA, via the Coolkill Lough Stream is ~9 km. The Dromore Lakes pNHA (00001) is located ~2 km to the southeast of the Proposed Development Site. There is no hydrological connection with this pNHA. RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 4 Water Framework Directive The Dromore_070 and Drumgole Lough SWBs achieved “Poor” status in the latest WFD Cycle (2019-2024) (www.catchments.ie). This status was unchanged from the previous WFD cycle (2016-2019). The Dromore_070 SWB is at risk of failing to meet its WFD objectives. Agriculture, urban wastewater and anthropogenic activities are listed as being the significant pressures. The risk status for Drumgole Lough is currently under review. The Cavan achieved “Good” status in the latest WFD cycle (2019-2024) (www.catchments.ie). This GWB is not at risk of failing to meet its WFD objectives. Flooding The OPW does not record the presence of any historic or recurring flood events in the vicinity of the Proposed Development site. There are no CFRAM or NIFM fluvial flood zones in the local area. The GSI Historic Surface Water Flood Map does not record any surface water flood zones in the local area. There are no historic or predictive groundwater flood zones in the local area. The closest mapped flood zones are associated with the Rockcorry Stream and several lake waterbodies ~700m to the northwest. These flood zones do not extend any distance away from the mapped river channel or lake waterbodies. Water Resources The Drumgole Lough is designated as a DWPA. The length of the hydrological flowpath between the site and the DPWA is ~9 km via the Coolkill Lough Stream and the Rockcorry Stream. The GSI does not map the presence of any Group Water Scheme or Public Water Scheme with a hydrological connection in the area of the Proposed Development site (www.gsi.ie). Wetlands According to the Map of Irish Wetlands (https://wetland.maps.arcgis.com) there are no wetlands mapped in the Proposed Development site. The closest mapped wetland is located ~212 m to the east of the Proposed Renewable Biogas Site and to the east of the L2320. This wetland is known as the Drumintin wetland (MIW_MN610). The site does not have protected status and the main habitats are listed as being fen, reed, swamp, scrub and wet grassland. The RFI refers to an “area of higher-quality intact bog”. Based on our assessment and inspection of aerial imagery, the only bog or wetland of interest, with the potential to contain higher quality intact bog, in the lands surrounding the site is Drumintin wetland. This wetland is identified on the Map of Irish Wetlands and is shown on Figure A below. Figure A also includes the existing drainage regime of the local area, including the roadside drains and field drains in the vicinity of the Proposed Renewable Biogas Plant Site and their hydrological connectivity to downstream watercourses. RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 5 Figure A: Proposed Development site, Wetland Area and Local Drainage Network The assessment presented below concentrates on the Proposed Renewable Biogas Plant Site, as soil storage at the Soil Relocation Area is no longer proposed. As a result, the former proposed Soil Relocation Area has been omitted from this hydrological/hydrogeological assessment. The Proposed Development has very limited potential to significantly affect groundwater quantity (i.e. groundwater levels) in the wetland area for the following reasons: • The separation distance between the Proposed Renewable Biogas Plant Site and Drumintin wetland (~212 m); • The presence of 2 no. public roads, the R189 and L2320, in the intervening lands. Drainage infrastructure associated with these existing roads acts as a hydraulic barrier between the Proposed Renewable Biogas Plant Site and the Drumintin wetland; • Existing field drains are also located within the former proposed Soil Relocation Area. These drains will also intercept shallow groundwater flows between the Proposed Renewable Biogas Plant Site and the Drumintin wetland; • The existing local surface water drainage infrastructure reduces shallow groundwater connectivity between the Proposed Renewable Biogas Plant Site and the Drumintin wetland; • Inspection of aerial imagery has revealed the presence of several surface water drains within the Drumintin wetland (identifiable on Figure A above). The wetland exists in a hydrologically modified state and is not designated; • The drains within and in the immediate vicinity of Drumintin wetland, are the primary control on groundwater levels within the wetland; • Ground elevations at the Proposed Renewable Biogas Plant Site range from ~93 to 111 mOD (with ground elevations increasing to the southwest). The lowest elevations at the Proposed Development site are ~6 m above the ground elevations at RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 6 Drumintin wetland. Therefore, excavations associated with the Proposed Development will be hydraulically separated from the water levels at Drumintin wetland; • All excavation works at the Proposed Renewable Biogas Plant Site will be above the groundwater table and there will be no requirement for groundwater dewatering or pumping during construction; • The Proposed Development drainage management plan has been designed in accordance with SuDS Principles (refer to engineering drawing MON MCA ZZ XX DR CE 2000). There will be no increase in surface water runoff rates. The majority of rainwater falling on-site will be used for the operation of the Proposed Development. Rainwater will be stored in underground attenuation tanks (designed to attenuate flows up to 100-yr rainfall plus 30% climate change allowance) and any water not used for operational purposes will be discharged to the downstream surface water drainage network at a restricted rate (the maximum discharge will be 83.5 L/s, the greenfield runoff rate during a 100-yr rainfall event); • The reduction in surface water runoff rates and the use of water for the AD plant will reduce flows to the downstream surface water drainage network which feeds into the Coolkill Lough Stream which flows adjacent to Drumintin wetland. However, given the small footprint of the Proposed Development relative to the wider catchment, any changes in downstream flow volumes within the stream are not expected to be significant. In addition, Drumintin wetland relies primarily on direct rainfall inputs rather than surface water inflows from the stream. The water levels in the wetland will not be significantly impacted by any minor reduction in flow volumes in the stream; • There will be no significant decrease in groundwater recharge rates at the Proposed Renewable Biogas Plant Site due to the small footprint of the Proposed Development and the existing hydrogeological regime which is characteri sed by low rates of groundwater recharge (~4-8% due to the presence of low permeability soils/subsoils); • The Proposed Development has been designed to maximise water efficiency and to reduce groundwater demand. Whilst a groundwater well is proposed in the underlying bedrock this will primarily be used to supply potable water and for sanitary purposes at a rate of 2 m3/day. This rate is equivalent to the abstraction rate for a private domestic well and will not have any significant impact on groundwater levels. This well will draw water from the underlying sandstone bedrock. Wetland areas are largely fed by rainwater and do not rely upon groundwater discharge from deeper bedrock aquifers; and, • The water for the operation of the AD plant (~45 m3/day) will be sourced primarily from rainwater harvesting. Water will only be sourced from the groundwater well during periods of low rainfall. However, the AD plant has been designed to minimise water demand, with the majority of water used being derived from recirculating liquids generated by the digestate process. The attenuation tanks also have a combined water storage capacity of 1,338 m3 which will reduce the requirement for groundwater abstraction during dry periods. Furthermore, the Proposed Development has very limited potential to significantly affect groundwater quality in the wetland area for the following reasons: • The separation distance between the Proposed Renewable Biogas Plant Site and the Drumintin wetland (~212 m); • The presence of existing drainage infrastructure (as discussed above) which reduces groundwater connectivity between the Proposed Renewable Biogas Plant Site and Drumintin wetland; RECEIVED: 28/08/2026 RFI Response Renewable Biogas Plant, Maghernakelly and Drumcall, Co. Monaghan ___________________________________________________________________________________________________ 7 • Therefore, there is very limited groundwater connectivity between the Proposed Renewable Biogas Plant Site and Drumintin wetland; • There will be no discharge of untreated or unattenuated water to the local surface water drainage network; • All water will pass through an appropriately sized Aqua-Swirl (or similar water treatment system) and an Aqua Filter Unit before entering the attenuation tanks. From here, the water will either be pumped to the plant or discharge to the existing drainage ditch in the north-east of the site; and, • There will be no discharge of foul water at the site , and all foul water will be treated at the Foul water Pumping Station (refer to engineering drawing MON MCA ZZ XX DR CE 2000). Therefore, no significant hydrogeological effects will occur on the wetland area during either the construction or operational phases of the Proposed Development. 3 CLOSURE In conclusion, following removal of the Soil Relocation Area from the Proposed Development, there is no identified hydrogeological linkage by which the Proposed Development could alter the hydrological balance of Drumintin Wetland or any other wetland feature in the surrounding area. Furthermore, the Proposed Development will not result in deterioration of any Water Framework Directive quality element or compromise achievement of Water Framework Directive objectives. We trust that the above assessment provides sufficient detail in response to RFI Item 2(c). Please do not hesitate to contact the undersigned should any further clarification be required. Yours sincerely, Michael Gill PGeo Civil Engineer and Hydrogeologist B.A., B.A.I., M.Sc., Dip Geol, MIEI, MCIWEM RECEIVED: 28/08/2026 © HYDRO-ENVIRONMENTAL SERVICES 22 Lower Main Street, Dungarvan, Co. Waterford, X35 HK11 T: +353-(0)58-441 22 F: +353-(0)58-442 44 E: info@hydroenvironmental.ie www.hydroenvironmental.ie RECEIVED: 28/08/2026