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HomeMy WebLinkAbout2660014 - F.I. Received Doc. - Drainage & Site Service ProposalsA L A N C L A R K E & A S S O C I A T E S THE RIDGE ENTERPRISE HUB, McGRATH ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 e: info@alanclarke.ie www.alanclarke.ie Drainage & Site Services Proposals for Proposed Extension to Existing Commercial Premises at Daly’s Yard, Dundalk Road, Carrickmacross, Co Monaghan for Frenda Ltd Planning Ref 26/60014 May 2026 RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Proposed Extension to Existing Commercial Premises at Daly’s Yard, Dundalk Road, Carrickmacross, Co Monaghan Introduction The proposed development will consist of a new single-storey extension to an existing commercial/retail building and the extension of the existing product storage yard to the rear (north east) of the building at Daly’s Yard, Dundalk Road, Carrickmacross, Co. Monaghan. The development will also include the provision of additional staff car parking spaces and alterations to the existing surface water pipe network and the provision of new surface water drainage to the new yard area. This document provides details relating to the existing and proposed site services and should be read in conjunction with the drawings which form part of this planning application that indicate the layouts, routes, and levels etc for the proposed site services. Foul Sewer A 100mm diameter uPVC foul sewer from the existing commercial/retail premises runs from the existing toilets and canteen in a northeasterly and then northerly direction and connects to an existing 225mm diameter Uisce Eireann foul sewer close to the north eastern boundary of the site. This public sewer discharges to an existing pumping station which is part of the town drainage network. The proposed extension/development will not affect the existing foul sewer, and no additional toilets or sanitary facilities will be provided as part of the proposed development. It is not intended to alter the existing foul sewer network in any way. The existing foul sewer network and associated manholes are indicated on drawing 26130-500 which is included as part of this planning submission with the foul pipework indicated in red. Surface Water / SuDS /Nature Based Solutions It is intended that the surface water drainage network for the existing retail/commercial premises will generally be retained as existing and that the new/extended yard area to the rear (north east) will generally discharge to ground via the permeable stone surface to this yard area. In this way, the existing predevelopment dissipation of the rain water to ground will be maintained. A 6m wide filter strip will be provided along the north eastern edge of the new yard area with a swale constructed along the full extent of this filter strip. The proposed surface water drainage and disposal regime from the extended yard area will ensure that the run-off from most rainfall events will discharge to ground via the permeable yard surface and the existing subsoils in the same manner that rain fall on the site currently discharges. The permeable yard surface and infiltration via existing subsoils will ensure that suspended solids and potential pollutants are filtered our prior to discharge to ground water. Any occasional run-off from the yard area due to extreme rainfall events will discharge across the proposed filter strip which will be formed with a grassed area with an even gradient towards the proposed swale. Any overground run-off from extreme rainfall events which does not dissipate to ground prior to reaching the swale will discharge to, and along the swale towards the outlet manhole at the north western end of the swale. A 150mm discharge pipe from this manhole will discharge to the stream along the north eastern side of the site. This manhole will be fitted with a hydro-brake which will limit the run-off to the pre-development greenfield run off rate for the site, thereby ensuring that the run-off to the stream does not exceed the existing greenfield run-off rate. RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie It is not intended to alter the existing surface water drainage regime for the existing retail building and commercial yard, with the exception of the alteration of a short length of existing surface water pipework to reroute this pipework around the proposed retail unit extension. Hydraulic & Water Quality Criteria The proposed surface water drainage for the site has been designed using the principles of sustainable drainage systems (SuDS) incorporating nature-based solutions in accordance with the Department of Housing, Local Government and Heritage best practice guidance document, and the CIRIA SUDS Manual (C697). The objective of this approach is to safely deal with run-off from extreme storm events, without putting public or property at risk, and avoid any increase in the pre-development flood risk associated with the receiving water course. The SuDs management train has been applied to the surface water design and aims to prevent run-off by reducing impermeable areas, managing run-off at source, and through site and regional controls. Four treatment train stages are achieved with the proposed run-off arrangement as described in detail below. These are as follows;  Permeable yard surface providing filtration and removal of suspended solids, and discharge to ground  Grassed filter strip providing filtration of run-off  Swale providing further filtration and attenuation  Oil interceptor providing final treatment and elimination of residual hydro-carbons prior to discharge to outfall This level of treatment meets and exceeds the recommendation of the SUDS Manual for standard commercial yards and delivery areas. Hydraulic Criteria will be met by controlling the rate of discharge of surface water from the proposed yard area on the developed site to match pre-development run-off rates. Site control will be incorporated in the system in the form of attenuation storage in the swale along the lower edge of the filter strip. It is proposed to generally discharge the normal rainfall from the new yard area to ground convey the permeable stone surface and subbase forming this yard area. Any run-off from this area in extreme rainfall events will follow the natural topography of the ground and run in a north easterly direction to the filter strip along the north eastern side of the yard area. This grass covered filter strip has been incorporated in order to allow the filtering out of suspended solids or pollutants from the first flush rainfall from the yard area prior to the run-off entering the drainage network. The run-off will flow over the filter strip to the swale from where it will be conveyed to the proposed surface water manhole at the north western end of the swale where it will enter the proposed pipe network (via a new surface water manhole) which will discharge to the existing stream at the north eastern site boundary. A flow restrictor will be fitted to the new manhole which will limit the run-off to the pre-development greenfield run off rate for the site, thereby ensuring that the run-off to the stream does not exceed the existing greenfield run-off rate. The swale will provide further filtration to the run-off and will provide attenuation storage for run-off. The exact size of the swale to attenuate any flood water exceeding the green-field run-off rate, will be determined following infiltration testing carried out on the site prior to the commencement of the development in accordance with the BRE Digest 365. This approach is consistent with the sustainable drainage system (SuDS) approach and in accordance with Monaghan County Development Plan 2019-2025. The run-off from the proposed yard area will pass through a new Class 1 bypass oil interceptor (Kingspan Klargester NSBP004 or similar) prior to discharge at the outfall manhole. While the oil interceptor would be considered redundant at present based on the RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie proposed design of the system, it will be provided in order to ensure adequate protectionto the stream in the event that the yard area is paved at a future date. The oil interceptor has been sized to provide adequate capacity to deal with the runoff from the entire site. The NSBP004 interceptor has capacity to cater for the maximum green-field run-off rate from the site. The design of the flow restrictor and interceptor will be based on the greenfield run-off rate from the pre-developed site as follows; Mean Annual Flood Flow/Green Field Run-off Rates (Qbar) The calculation of greenfield runoff estimation for the site has been carried out using HR Wallingford software and is appended to this document. The calculation indicates the following run-off rates; Qbar for 1 year return period = 2.0 l/sec Qbar for 30 year return period = 3.9 l/sec Qbar for 100 year return period = 4.6 l/sec Surface Water Sewer Outfall The outflow from the surface water system will be restricted by means of a Hydrobrake Optimum vortex flow control at the new surface water manhole at the end of the swale (the only manhole on the new surface water system) as indicated on the site layout drawing, as referred to above, to limit the discharge flow rate from the proposed development to the stream along the north eastern boundary of the site to the predevelopment run-off rate. A new headwall will be formed at the stream at the discharge point for the new surface water pipe. Water Quality Criteria In order to provide filtration to the run-off from the existing and proposed paved surfaces, an isolator row will be incorporated in each attenuation chamber system. This will filter out sediments from the first flush rainfall and also allow for maintenance of the attenuation chamber to ensure its long-term functionality. This isolator row is formed by encasing a full row of the attenuation chambers in a suitable non-woven geotextile and creating a baffle and over flow weir in the entry manhole which directs the run-off through the isolator row from where it percolates through the geotextile and into the remainder of the attenuation chamber. Filtration of the run-off is achieved in this process. (An extract from the Storm Tech Design Manual is appended to this report which refers to this isolator row concept). The existing car park and road areas are served by a dedicated petrol interceptor which will be retained if deemed to be adequate and suitable. The condition and functionality of this interceptor will need to be verified on site and any necessary maintenance or repairs carried out. The run-off from the proposed and a portion of the existing site hardstanding, macadam road and parking areas of the site (which flows through the larger attenuation area) will pass through a new Class 1 bypass oil interceptor (Kingspan Klargester NSBP004 or similar) prior to discharge at the outfall manhole. The oil interceptor has been sized to provide adequate capacity to deal with the runoff from the entire site. The NSBP004 interceptor has capacity to cater for the calculated flow rate as indicated in the appended calculations. RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Appendix 1 HR Wallingford Greenfield Runoff Rate Calculation RECEIVED: 29/05/2026 Greenfield runoff rate estimation tool www.uksuds.com | Greenfield runoff rate estimation tool (https://www.uksuds.com/) This is an estimation of the greenfield runoff rates that are used to meet normal best practice criteria in line with Environment Agency guidance “Rainfall runoff management for developments”, SC030219 (2013), the SuDS Manual C753 (CIRIA, 2015) and the non-statutory standards for SuDS (Defra, 2015). This information on greenfield runoff rates may be the basis for setting consents for the drainage of surface water runoff from sites. Project details Date Calculated by Reference Model version Location Site name Site location Site easting (Irish Grid) Site northing (Irish Grid) Site easting (Irish Transverse Mercator) Site northing (Irish Transverse Mercator) Site details Total site area (ha) + – © OpenStreetMap (https://www.openstreetmap.org/copyright) contributors. ha 16/05/2026 AC 26130 2.2.3 Daly's Yard Carrickmacross 284805 303530 684738 803541 0.55 RECEIVED: 29/05/2026 Greenfield runoff Method Method IH124 My value Map value SAAR (mm)994 How should SPR be derived? WRAP soil type 3 SPR QBar (IH124) (l/s) Growth curve factors My value Map value Hydrological region 13 1 year growth factor 2 year growth factor 10 year growth factor 30 year growth factor 100 year growth factor 200 year growth factor Results Method Flow rate 1 year (l/s) Flow rate 2 year (l/s) Flow rate 10 years (l/s) Flow rate 30 years (l/s) Flow rate 100 years (l/s) Flow rate 200 years (l/s) Please note runoff estimation is subject to significant uncertainty. Results are therefore normally reported to only 1 decimal place. Where 2 decimal places are provided, this does not indicate accuracy to this level, it has been adopted to prevent ‘zero’ figures from being reported. Outputs less than 0.01 l/s are reported as 0.01 l/s. Disclaimer This report was produced using the Greenfield runoff rate estimation tool (2.2.3) developed by HR Wallingford and available at uksuds.com (https://www.uksuds.com/). The use of this tool is subject to the UK SuDS terms and conditions and licence agreement, which can both be found at uksuds.com/terms-conditions (https://www.uksuds.com/terms-conditions). The outputs from this tool have been used to estimate Greenfield runoff rates. The use of these results is the responsibility of the users of this tool. No liability will be accepted by HR Wallingford, the Environment Agency, Centre for Ecology and Hydrology, Wallingford Hydrosolutions or any other organisation for the use of these data in the design or operational characteristics of any drainage scheme. IH124 mm WRAP soil type 3 l/s 13 l/s l/s l/s l/s l/s l/s 994 0.37 2.4 0.85 0.95 1.4 1.65 1.95 2.15 IH124 2.0 2.3 3.3 3.9 4.6 5.1 RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Appendix 2 Maintenance Details for Surface Water Network RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Proposed Maintenance Proposals and Schedule for Site and Construction Phase Proposed Drainage System The proposed surface water collection system will consist of a very limited extent of piped drainage network discharging surface water from the proposed swale to the outfall at the stream as shown on the proposed site layout drawing prepared by Alan Clarke & Associates (drawing number 26130500). The surface water discharge from the site will be restricted by means of hydrobrake flow restrictors. No proprietary attenuation chambers will be utilized which will limit the requirement for maintenance of the system. Maintenance Requirements & Proposals In order for the surface water drainage system to function correctly in the long term, it is essential that a programme of regular maintenance of the collection and attenuation elements of the system is carried out. The permeable surface of the stone yard area needs to be maintained to ensure that its permeability is maintained. An annual inspection of this surface should be carried out – particularly in the trafficked areas and any over-consolidation leading to sealing of the surface should be rectified by cleaning and reinstatement of the surface. This process would normally only be required to the upper 50mm to 70mm of the yard surface. This inspection and maintenance would be the responsibility of the operator of the site. The limited piped conveyance system is designed to ensure minimum self-cleansing velocities and should require little or no ongoing maintenance. The filter strip will be uniformly sloped grass surface and should be maintained in the normal way for any soft landscaped area by means of mowing and collection of any debris or litter. An annual inspection of the filter strip should be undertaken by the site operator to ensure that it is functioning adequately and that no build up of sediment has occurred. The site attenuation will be provided by means of a grassed swale along the lower edge of the filter strip. Again, this will be maintained by regular moving and cleaning of any litter or debris as the need arises. An annual inspection of the swale should be undertaken by the site operator to ensure that it is functioning adequately and that no blockages or damage has occurred. The proposed SUDS features provide the benefit of their being monitored and maintained as part of the normal maintenance of the site. RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Construction Phase Following completion of the construction of the drainage system and associated pipes and manholes etc and prior to their connection to the stream, the pipes and manholes will be cleaned by a specialist drain cleaning contractor and the wash water removed by suction pumping. This will be completed by the contractor for the works prior to the opening of the outfall at the stream. This will ensure that the pipe network and outfall will not become an outlet for the cleaning water and associated sediment etc. Silt fences will be erected inside the boundary of the construction site as necessary in order to prevent run-off of silt laden water from the construction areas to adjacent areas of the site or adjoining sites during the course of the construction. Again, this will be the responsibility of the contractor for the works. RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Maintenance & Safety Data Sheets (Hydro-Brake) RECEIVED: 29/05/2026 HRD-FM04/16 E/0703 HYDRO-BRAKE® FLOW CONTROL MAINTENANCE AND SAFETY DATA SHEET MAINTENANCE Normally, little maintenance is required as there are no moving parts within the Hydro-Brake® Flow Control. Experience has shown that if blockages occur they do so at the intake, and the cause on such occasions has been due to a lack of attention to engineering detail such as approach velocities being too low, inadequate benching, or the use of units below the minimum recommended size. Hydro-Brake® Flow Controls are fitted with a pivoting by-pass door, which allows the manhole chamber to be drained down should blockages occur. The smaller type conical units, below the minimum recommended size, are also supplied with roding facilities or vortex suppressor pipes as standard. Following installation of the Hydro-Brake® Flow Control it is vitally important that any extraneous material i.e. Building materials are removed from the unit and the chamber. After the system is made live, and assuming that the chamber design is satisfactory, it is recommended that each unit be inspected monthly for three months and thereafter at six monthly intervals with hose down if required. If problems are experienced please do not hesitate to contact the company so that an investigation may be made. Hydro-Brake® Flow Controls are typically manufactured from grade 304 Stainless Steel which has an estimated life span in excess of the design life of drainage systems. COSHH Hydro-Brake® Flow Controls are manufactured from Stainless Steel, which is not regarded as hazardous to health and exhibits no chemical hazard when used under normal circumstances for the stated applications. MANUAL HANDLING The handling of Hydro-Brake® Flow Controls should be in accordance with current legislation and regulations: x The Health and Safety at Work Act 1972. x The Management of Health and Safety at Work Regulations 1992. x The Manual Handling Operations Regulations 1992. All published and printed by the Health and Safety Executive. RECEIVED: 29/05/2026 A L A N C L A R K E & A S S O C I A T E S CASTLEBLAYNEY ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN t: 042 9740071 f: 042 9746645 e: info@alanclarke.ie www.alanclarke.ie Appendix 3 Standard Construction Details RECEIVED: 29/05/2026 ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN p: 042-9740071 f: 042-9746645 e: info@alanclarke.ie ALAN CLARKE & ASSOCIATES consulting civil & structural engineers project title scale drawing no rev dateRECEIVED: 29/05/2026 ENTERPRISE CENTRE, DUBLIN ROAD, CASTLEBLAYNEY, CO MONAGHAN p: 042-9740071 f: 042-9746645 e: info@alanclarke.ie ALAN CLARKE & ASSOCIATES consulting civil & structural engineers project title scale drawing no rev dateRECEIVED: 29/05/2026