Homers Farm Inert Landfill: Environmental Setting and Site Design Report
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Homers Farm inert landfill: Environmental Setting and Site Design report 29 April 2019 T1.02 Homers Farm inert landfill: Environmental Setting and Site Design report Prepared for Harleyford Aggregates Ltd Marina Building Harleyford Estate Marlow Buckinghamshire SL7 2DX Report reference: 60594R14, April 2019 Report status: Final CONFIDENTIAL New Zealand House, 160-162 Abbey Foregate, Registered Office: Shrewsbury, Shropshire Stantec UK Ltd SY2 6FD Buckingham Court Kingsmead Business Park Telephone: +44 (0)1743 276 100 Frederick Place, London Road Facsimile: +44 (01743 248 600 High Wycombe HP11 1JU Registered in England No. 1188070 Homers Farm inert landfill: Environmental Setting and Site Design report Page i Homers Farm inert landfill: Environmental Setting and Site Design report This report has been prepared by Stantec UK Ltd (Stantec) in its professional capacity as environmental specialists, with reasonable skill, care and diligence within the agreed scope and terms of contract and taking account of the manpower and resources devoted to it by agreement with its client and is provided by Stantec solely for the internal use of its client. The advice and opinions in this report should be read and relied on only in the context of the report as a whole, taking account of the terms of reference agreed with the client. The findings are based on the information made available to Stantec at the date of the report (and will have been assumed to be correct) and on current UK standards, codes, technology and practices as at that time. They do not purport to include any manner of legal advice or opinion. New information or changes in conditions and regulatory requirements may occur in future, which will change the conclusions presented here. This report is confidential to the client. The client may submit the report to regulatory bodies, where appropriate. Should the client wish to release this report to any other third party for that party’s reliance, Stantec may, by prior written agreement, agree to such release, provided that it is acknowledged that Stantec accepts no responsibility of any nature to any third party to whom this report or any part thereof is made known. Stantec accepts no responsibility for any loss or damage incurred as a result, and the third party does not acquire any rights whatsoever, contractual or otherwise, against Stantec except as expressly agreed with Stantec in writing. Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page ii Name Signature Author Robert Gordon Checked by Robert Sears Reviewed by Robert Sears Revision record: Issue Date Status Comment Author Checker Reviewer 1 29/04/19 Final - RAG RCS RCS Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page iii Contents 1 INTRODUCTION 1 1.1 Report context 1 1.2 Operator and agent 1 1.3 Pre-application reference 1 1.4 Proposed activity planning status 1 2 SITE DETAILS AND RECEPTORS 3 2.1 Site details 3 2.2 Proposed Environmental Permit boundary 3 3 SOURCE 4 3.1 Historical development 4 3.2 Proposed development 4 3.2.1 Presence of a hydrocarbon contamination plume in groundwater 4 3.2.2 Presence of a stored water tunnel beneath the Site 6 3.2.3 Former landfills 6 3.3 Installation details 6 3.3.1 Waste types and quantities 6 3.3.2 Proposed operational phasing 7 3.3.3 Final landform and after use 7 3.4 Installation engineering 7 3.4.1 Groundwater management 7 3.4.2 Geological barrier 10 3.4.3 Restoration 11 3.4.4 Aftercare 11 3.5 Leachate management and monitoring 11 3.5.1 Leachate generation and management 11 3.5.2 Leachate monitoring 11 3.6 Landfill gas management and monitoring 11 Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page iv 3.6.1 Landfill gas generation and management 11 3.6.2 Landfill gas monitoring 12 3.7 Surface water management 12 4 PATHWAYS 14 4.1 Climate 14 4.2 Geology 14 4.2.1 Regional geology 14 4.2.2 Local geology 15 4.3 Hydrology 16 4.3.1 Flood risk 20 4.3.2 Surface water abstractions 20 4.3.3 Discharge consents 20 4.3.4 Surface water quality 20 4.4 Hydrogeology 20 4.4.1 Groundwater abstractions 21 4.4.2 Aquifer properties 21 4.4.3 Groundwater flow 21 4.4.4 Groundwater quality 22 4.5 Man-made subsurface pathways 23 4.6 Receptors and compliance points 23 4.6.1 Groundwater 23 4.6.2 Surface water 23 4.6.3 Amenity (nuisance and health issues) receptors 24 4.6.4 Habitat receptors 24 5 POLLUTION CONTROL MEASURES 25 5.1 Site Engineering 25 5.1.1 Basal and sidewall engineering 25 5.2 Restoration 26 5.3 Surface water management 26 Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page v 5.4 Post closure controls (Aftercare) 26 6 MONITORING 28 6.1 Leachate 28 6.2 Groundwater and gas 28 6.3 Surface water 28 6.4 Topographical survey 28 7 SITE CONDITION REPORT 29 8 CLOSURE 30 9 REFERENCES 31 TABLES Table 4.1 Average monthly rainfall data at Heathrow airport (1948 to 2017) 14 Table 4.2 Summary of regional geology 15 Table 4.2 Borehole summary 17 Table 4.3 Groundwater level summary (2011 to 2018) 22 DRAWINGS Drawing ESSD1 Site location Drawing ESSD2 Site layout Drawing ESSD3 Operational phasing plan Drawing ESSD4 Restoration plan Drawing ESSD5 Artificial ground and superficial geology Drawing ESSD6 Solid geology Drawing ESSD7 Local hydrology Drawing ESSD8 Local hydrogeology Drawing ESSD9 Receptors Drawing ESSD10 Site monitoring plan Drawing ESSD11 Site Environmental Permit boundary Drawing ESSD12 Site investigation locations Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page vi APPENDICES Appendix A Planning application and decision document Appendix B Environmental data report and historical mapping Appendix C Groundwater hydrographs Appendix D Groundwater quality data Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page 1 1 Introduction 1.1 Report context This section of the Environmental Permit application corresponds to Question 1, Appendix 4 of Part B4 (Version 10, April 2018) of the application forms, which requires the provision of an Environmental Setting and Site Design (ESSD) report for a proposed inert landfill. The aim of this report is to describe the regulated facility in relation to its environmental setting, identifying the source term, pathways and receptors that will be used as the basis for the following supporting risk assessments: - Environment Risk Assessment (ERA) - which is required to consider the potential environmental impacts from the proposed landfill (Stantec, 2019a). - Hydrogeological Risk Assessment (HRA) - which is specifically required since the Site is located on a sensitive aquifer (Stantec, 2019b). - Gas Risk Assessment (GRA) - which is required to consider the possible effects of gases potentially generated from the proposed landfill (Stantec, 2019c). - Stability Risk Assessment (SRA) - which is required to establish the structural and physical stability of the landfill over its entire lifecycle (GWP, 2019). 1.2 Operator and agent Mineral rights for a site known as Homers Farm, which is located off Short Lane, Staines-on-Thames, TW19 7BQ (the Site), have been transferred from Henry Streeter (Sand and Ballast) Ltd to Harleyford Aggregates Ltd (Harleyford) (registered in England and Wales as Company Number 00819220). Harleyford is currently preparing to begin mineral extraction from the Site. As part of these preparations, Harleyford must apply to the Environment Agency for an appropriate Environmental Permit to dispose of inert materials by landfilling during the eventual restoration of the quarry void. Stantec UK Ltd (Stantec) has been commissioned by Harleyford to prepare the Environmental Permit application for the proposed inert landfill. Harleyford will be the Operator of the Site as named in the Environmental Permit. 1.3 Pre-application reference A pre-application meeting was held with the Environment Agency (the Agency) on 31 July 2018 at Hengrove landfill to discuss the proposals (Environment Agency, 2018a); and this was followed by a teleconference on 16 November 2018. (Environment Agency, 2018b); The Agency’s pre- application reference number is EPR/GB3404HX/A001 (EAWML404982). 1.4 Proposed activity planning status Surrey County Council (SCC) granted planning permission (ref: SP/13/00141/SCC) to Henry Streeter (Sand and Ballast) Ltd (the planning applicant) on 12 January 2015 to allow the extraction of sand and gravel and subsequent restoration to agriculture land using inert materials (see Appendix Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page 2 A). As outlined above, mineral rights have subsequently been transferred to Harleyford who intend to work the minerals from the Site and complete the required restoration. Details of the planning application and a copy of the Decision Document are included in Appendix A. Report Reference: 60594R14 Report Status: Final Homers Farm inert landfill: Environmental Setting and Site Design report Page 3 2 Site details and receptors 2.1 Site details The Site occupies an area of approximately 10.5 hectares and is located c. 1 km to the south of Heathrow Airport in the west of London (see Drawing ESSD1). The Site itself is located on agricultural land, although the surrounding area is largely developed with the A30 located along the southern boundary; with the settlements of Ashford to the south; Stanwell to the west and Feltham to the east. A large aviation fuel storage facility which supplies Heathrow Airport and a water treatment facility, also associated with the airport, are located immediately to the north and north-east of the Site respectively.