Ied Baseline and Site Condition Report

IED BASELINE AND SITE CONDITION REPORT

Bracknell Data Centre – Emergency Back-Up Generation Installation Permit Application EPR/FP3900LE/A001

20305B-RPS-XX-XX-HS-Z-9743

JER8748 IED Baseline and Site Condition Report V2 R2 16 March 2021

rpsgroup.com

Quality Management

Version Revision Authored by Reviewed by Approved by Date

1 0 Alice Gibbs Jennifer Stringer 15 February 2021

1 1 Alice Gibbs Jennifer Stringer Jennifer Stringer 26 February 2021

Olan Howell/Jennifer 2 1 Alice Gibbs Jennifer Stringer 04 March 2021 Stringer

2 2 Alice Gibbs Jennifer Stringer Jennifer Stringer 16 March 2021

Approval for issue

Jennifer Stringer Technical Director 04 March 2021

File Name

20305B-RPS-XX-XX-HS-Z-9743 210316 R JER8748 IED Baseline and SCR V2 R2

Save as otherwise specified in (i) the AIA Document B101 Standard Form of Agreement dated 16 June 2015 between the client as owner and RPS Group Limited as architect, and (ii) the Master Agreement Local Country Addendum Amendment dated 16 June 2015 between the client and RPS Consulting Services Ltd,, the report has been prepared for the exclusive use of our client and unless otherwise agreed in writing by RPS Group Plc, any of its subsidiaries, or a related entity (collectively 'RPS'), no other party may use, make use of, or rely on the contents of this report. The report has been compiled using the resources agreed with the client and in accordance with the scope of work agreed with the client. No liability is accepted by RPS for any use of this report, other than the purpose for which it was prepared. The report does not account for any changes relating to the subject matter of the report, or any legislative or regulatory changes that have occurred since the report was produced and that may affect the report. RPS does not accept any responsibility or liability for loss whatsoever to any third party caused by, related to or arising out of any use or reliance on the report.

RPS accepts no responsibility for any documents or information supplied to RPS by the Applicant and Applicant’s consultants to the extent such reliance is reasonable and not contrary to other information known by RPS. It is expressly stated that no independent verification of any documents or information supplied by the Applicant and Applicant’s consultants has been made. RPS has used reasonable skill, care and diligence in compiling this report consistent with the skill and care ordinarily provided by reasonably diligent professional practicing under the same or similar circumstances for projects of the same or similar size scope and nature. No part of this report may be copied or reproduced, by any means, without the prior written consent of RPS.

Prepared by: Prepared for: RPS Amazon Data Services UK Limited Alice Gibbs

Environmental Consultant

6/7 Lovers Walk Brighton BN1 6AH T +44 1273 546800

E [email protected]

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Contents 1 INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 Key Objectives ...... 1 1.3 Description of Permitted Activities ...... 2 2 APPLICATION SITE CONDITION REPORT ...... 3 2.1 Application Phase...... 3 2.2 Site Condition Report Summary ...... 3 3 STAGE 1 – IDENTIFY WHICH HAZARDOUS SUBSTANCES ARE USED, PRODUCED OR RELEASED AT THE INSTALLATION AND PRODUCE A LIST OF THESE SUBSTANCES ...... 4 4 STAGE 2 – IDENTIFYING THE RELEVANT HAZARDOUS SUBSTANCES...... 6 4.2 Diesel, Lubricating and Waste Oil ...... 6 4.3 Ethylene Glycol ...... 6 5 STAGE 3 – ASSESSMENT OF THE SITE-SPECIFIC POLLUTION POSSIBILITY ...... 7 5.2 Diesel ...... 7 5.3 Site Specific Pollution Possibility ...... 8 6 STAGE 4 – PROVIDE A SITE HISTORY ...... 9 6.2 General Site History ...... 9 6.3 Previous Ground Investigations ...... 9 6.4 Potential Historic Contaminants ...... 11 7 STAGE 5 – IDENTIFY THE SITE’S ENVIRONMENTAL SETTING ...... 12 7.1 Site Setting and Sources of Desk Study Information ...... 12 7.2 Topography ...... 12 7.3 Geology ...... 12 Made Ground ...... 13 London Clay Formation ...... 13 7.4 Hydrogeology ...... 13 Source Protection Zone ...... 13 7.5 Hydrology ...... 13 Flood Risk ...... 13 7.6 Environmental Consents, Licences, Authorisations, Permits and Designations for the Site and Surrounding Areas ...... 13 Water Discharges and Abstraction Licences ...... 13 Landfill Sites ...... 14 Waste Treatment or Disposal Sites ...... 14 Permitted Installations ...... 15 Statutory Designated / Sensitive Receptors within 10 km ...... 15 Mining 16 COMAH ...... 16 Radon 16 Registered Radioactive Substances...... 16 8 STAGE 6 – SITE CHARACTERISATION ...... 17 Field Evidence of Contamination ...... 17 Sensitivity of Water Environment...... 17 8.2 Conceptual Site Model ...... 17 9 STAGE 7 – SITE INVESTIGATION ...... 18 RPS Ground Investigation ...... 19 10 STAGE 8 – PRODUCE A BASELINE REPORT...... 20 Ground Gas ...... 20 Asbestos ...... 20 Polyaromatic Hydrocarbons ...... 20 VOCs and SVOCs ...... 20

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TPH 20 PCBs 21 Metal and Inorganics ...... 21 11 OPERATIONAL SITE CONDITION REPORT ...... 22 11.1 Operational Phase...... 22 11.2 Site Condition Report Summary ...... 22 12 SURRENDER SITE CONDITION REPORT ...... 23 13 CONCLUSIONS ...... 24

Tables Table 3-1: Chemical Inventory ...... 4 Table 6-1: Substantiated Pollution Incident Register ...... 11 Table 7-1: Site Geology ...... 12 Table 7-2: Summary of Discharge Consents ...... 14 Table 7-3: Summary of Historical Landfill Sites ...... 14 Table 7-4: Summary of Waste Activities (excluding exemptions) ...... 15 Table 7-5: Summary of Installation Sites ...... 15 Table 7-6: Statutory Designated Sites ...... 15 Table 8-1: Conceptual Site Model ...... 17 Table 9-1: Ground Gas Results ...... 18 Table 9-2: Groundwater Risk Estimation (source: Arcadis 2020 report) ...... 18 Table 9-3: Soil Risk Estimation (source: Arcadis 2020 report) ...... 19

Drawings Drawing 1 Location Plan Drawing 2 Proposed Permit Boundary Drawing 3 Drainage Plan Drawing 4 Statutory Designated Sites within 5 km Drawing 5 EA Conservation Screening Report

Appendices Appendix A Groundsure Report 2020 Appendix B CBRE Phase I Report 2018 Appendix C CBRE Phase II Report 2018 Appendix D Site Investigation 2020

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1 INTRODUCTION

1.1 Background 1.1.1 This report supports an application for an Environmental Permit (EPR/FP3900LE/A001) for the Bracknell Data Centre emergency back-up generating facility situated at Amen Corner Business Park, Cain Road, Binfield, Bracknell, RG12 1HN. The site is centred at National Grid Reference SU 84809 69006. The proposed permit boundary for the installation is shown on Drawing 2_20305B-RPS-XX-XX-RP-T-9746. 1.1.2 The proposed facility will be regulated under Schedule 1, Part 2, Section 1.1 A (1) of the Environmental Permitting (England and Wales) Regulations 2016 (as amended). To support the application for the permit, there is a requirement to provide an Industrial Emissions Directive (IED) Baseline Report as well as a Site Condition Report (SCR). 1.1.3 This report has been prepared in accordance with the European Commission Guidance1 concerning baseline reports required under the IED and also the Environment Agency’s H5 Horizontal Guidance2. 1.1.4 The IED, Article 22, paragraphs 2 to 4, contains provisions for the definitive cessation of activities involving the use, production or release of Relevant Hazardous Substances (RHS) in order to prevent and tackle potential soil and groundwater contamination from such substances. A key tool in this respect is the establishment of a ‘baseline report’ where an activity involves the use, production or release of RHS and having regard to the possibility of soil and groundwater contamination. The report will form the basis for a comparison with the state of contamination upon definitive cessation of activities. Where information produced pursuant to other national or union law reflects the state at the time the report is drawn up, that information may be included in, or attached to, the baseline report. 1.1.5 RPS has prepared this report based on information and data available at the time of preparation of the report.

1.2 Key Objectives 1.2.1 The key objectives of this report are to: • Establish the environmental setting of the site and determine its environmental sensitivity; • Identify activities that are currently undertaken at the site, including the identification of Relevant Hazardous Substances and preventative measures implemented to protect land and groundwater; • Establish the extent of historical contamination in the soil and groundwater in areas where current and/or future processes may include similar potentially contaminating substances; • To identify the Site Conditions at the site at the point of varying the permit for the facility (baseline condition) such that they may be used as a point of reference to determine whether the site has been contaminated during the site's permitted operation in line with IED and Environmental Permitting Regulations requirements; and • To provide conclusions on whether land quality has been impacted from historical activities.

1 https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32010L0075&from=EN

2 Environment Agency, H5 Guidance for Applicants, Environmental Permitting Regulations, Site Condition Report – Guidance and Templates, May 2013

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1.2.2 With respect to the IED eight stage process, a summary of each stage is outlined below along with where it is addressed within this report: • Stage 1 - Identify hazardous substances used, produced or released at the installation. This is addressed within Section 3 of this report; • Stage 2 - Identify relevant hazardous substances used, produced or released at the installation from the list of hazardous substances identified in Stage 1. This is addressed within Section 4 of this report; • Stage 3 – Undertake an assessment of site-specific pollution possibility for relevant hazardous substances. This is addressed within Section 5 of this report; • Stage 4 – Evaluation of Site History and potential for relevant hazardous substances to be present in soils and groundwater. This is addressed within Section 6 of this report; • Stage 5 – Evaluation of Environmental Setting to determine the fate of potential emissions of relevant hazardous substances This is addressed within Section 7 of this report; • Stage 6 – Site Characterisation that synthesises findings of Stage 5 and 6 on the basis of a Conceptual Site Model. This is addressed within Section 8 of this report; • Stage 7 – Site Investigation (including sampling strategy). This is addressed within Section 9 of this report; and • Stage 8 – Production of Baseline Report. This is addressed within Section 10 of this report.

1.3 Description of Permitted Activities 1.3.1 The data centre will be served by a direct connection to the national electricity grid. In case of a break in supply, back-up generation will be provided by emergency diesel generators. The data centre building will be served by 10 x 6.8 MWth and 1 x 1.7 MWth back-up generators within a compound each with an individual associated stack. The smaller generator (1.7 MWth) will be for emergency back-up of the supply to the administrative sections of the data centre. 1.3.2 Cooling for the gas engines will be provided by radiators. 1.3.3 The engines will be individually containerised within a compound housing 11 engines. Individual engine containers are sealed and bunded. Diesel will be stored on site and it is anticipated that the compound will be served by a main top-up tank holding approximately 40,000 litres. Each of the 6.8 MWth engines will also have an associated 16,000 litre belly tank. The smaller 1.7 MWth engine will have an associated belly tank with 6,000 litre capacity. 16,000 litres and 6,000 litres represents the approximate volume of diesel required for 24 hours operation of each engine running at full load. All tanks will be above ground and double skinned. The main top-up tank will be within a bund with a capacity of 110% of the storage capacity of the tank. Each belly tank is containerised and self-bunded to contain 110% of the storage capacity of the tank. All tanks will comply with the Oil Storage Regulations3. 1.3.4 A detailed description of the facility is provided in the main permit application document (20305B- RPS-XX-XX-FR-T-9740).

3 SI 2001/2954. The Control of Pollution (Oil Storage) (England) Regulations 2001

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2 APPLICATION SITE CONDITION REPORT

2.1 Application Phase 2.1.1 This SCR contains information on the condition of the site from 2021, at the time of the application for an environmental permit. The site history prior to 2021 has been reviewed as part of this SCR where known and commented on within this report.

2.2 Site Condition Report Summary

1.0 Site Details

Name of the applicant Amazon Data Services UK Limited

Activity address Cain Road, Amen Corner, Binfield, RG12 1HN

National grid reference SU 84809 69006

Site area (ha) 0.25 Ha Document reference and dates for Site 20305B-RPS-XX-XX-HS-Z-9743 IED Baseline and Site Condition Condition Report at permit application and Report (RPS, 2021) surrender Document references for site plans (including Drawing 1_20305B-RPS-XX-XX-RP-T-9745 location and boundaries): Drawing 2_20305B-RPS-XX-XX-RP-T-9746

2.0 Condition of the land at permit issue Environmental setting including: • Topography • Geology Details of the environmental setting are provided in Section 7 of this • Hydrogeology SCR and Baseline Report. • Hydrology • Environmental Consents, Licences, Authorisations, Permits and Designations Pollution history including: Pollution history details are • Location, nature of incidents or direct discharges that may have affected soil provided in Section 6 & 8 of this or groundwater SCR and Baseline Report. • Historical land uses and associated contaminants Any details regarding historical Evidence of historic contamination, for example, historical site investigation, contamination at the site are assessment, remediation and verification reports (where available) provided in Section 6 & 8 of this SCR and Baseline Report. Baseline soil and groundwater Details regarding baseline soil and groundwater reference data at the site are provided reference data in Sections 6 & 9 of this SCR and Baseline Report. Ground investigation information obtained in 2018 and 2020, included in Appendix C Supporting information and Appendix D.

3.0 Permitted activities Permitted activities Details regarding permitted activities on the proposed site are provided in Section 1 of this SCR. Non-permitted activities undertaken N/A Document references for: • plan showing activity layout; and • Drawing 2_20305B-RPS-XX-XX-RP-T-9746 • environmental risk assessment. • 20305B-RPS-XX-XX-RP-T-9742 – Environmental Risk Assessment

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3 STAGE 1 – IDENTIFY WHICH HAZARDOUS SUBSTANCES ARE USED, PRODUCED OR RELEASED AT THE INSTALLATION AND PRODUCE A LIST OF THESE SUBSTANCES

3.1.1 The IED Baseline Report relates to contamination risk associated with “hazardous substances” used, produced and/or released by the proposed AWS installation. Hazardous substances are defined as substances or mixtures defined in Article 3 of Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on Classification, Labelling and Packaging of substances and mixtures (the “CLP Regulations”). The determination of whether a substance is a hazardous substance is largely determined using the substance CAS Number and European Chemicals Agency (ECHA) database4. 3.1.2 Hazardous substances have been identified in the following materials on site: • Diesel; • Lubricating oil; • Ethylene glycol; and • Waste lubricating oil. 3.1.3 Table 3-1 provides details of materials, expected usage or volumes produced, storage and potential environmental effects. Table 3-1: Chemical Inventory

Raw Nature CAS Expected usage Storage Material Number (approximate) Diesel Liquid fuel oil, 68334-30-5 246,230 litres per 1 x 40,000 litre main top up tanks. complex combination annum during 10 x 16,000 litre belly tank (1 per of hydrocarbons routine testing*. engine) produced by the 640 litres per engine distillation of crude oil 1 x 6,000 litre belly tanks (1 per 1.7 per hour during MWth engine) emergency use. Lubricating Refined hydrocarbon Various Low usage, limited No routine storage on site, brought oil with additives to top up. onto site on an as needed basis. Onsite storage limited to system inventory. Ethylene Liquid coolant mono- 107-21-1 Very low usage, Used as an additive to coolant glycol constituent substance limited to top-up. water there will be no routine storage on site. This substance will be present diluted within the closed loop cooling system for the engines. Waste Refined hydrocarbon Various Low, dependant on No routine storage onsite, waste oil lubricating with additives usage. will be removed as part of oil maintenance contract.

* Assumes: all engines tested at 25% load for 0.5 hours every 2 weeks; and all engines tested at 100% load for 1.5 hours twice a year. 3.1.4 Stack emissions are not considered to be hazardous in relation to ground or groundwater. 3.1.5 Diesel will be stored in a main top-up tank with a capacity of approximately 40 m3. In addition, each engine will have an associated belly tank. For the 6.8 MWth engines these will be

4 https://echa.europa.eu/

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3 3 approximately 16 m for the 1.7 MWth engine this will be approximately 6 m . It is estimated that approximately 16,000 litres diesel will allow for 24 hours run time for each engines at 100% load. 3.1.6 The belly tanks will be automatically re-filled from the relevant main top-up tank via above ground fill lines as shown on Drawing 2_20305B-RPS-XX-XX-RP-T-9746. The main top-up tank will be re- filled from fuel delivery vehicles in the designated bunded area. All delivery staff and maintenance engineers will be trained and will hold contact details for the relevant employees to alert in the event of an incident. Contact details will also be held local to the filling point. 3.1.7 In the event that the cooling circuit requires a top-up, or a spillage is identified, the engine Maintenance Contractor will be responsible for overseeing this and notifying the Operator of any spillage incident and actions taken in accordance with the incident reporting system. 3.1.8 There will be a very small aqueous discharge from the engine stacks as a result of rainfall into the stacks. This may be contaminated with acid gases from the exhaust gas and therefore may be weakly acidic (pH 4 – 6). The discharge will be rainfall dependent, but is estimated to be approximately 1.1 m3 per annum. Due to the nature of the waste waters and very low volume being discharged, it is not considered a relevant hazardous substance for the purpose of this site condition and baseline report. No other process waters are produced at the installation. Rainwater run-off from containers, roofs and hardstanding will be discharged from the site. This will be directed to the drainage system for the wider data centre site. This drainage system will include oil interceptors and attenuation ponds prior to discharge into the local surface water network. Maintenance procedures are in place for the interceptor to ensure that it remains in good working order to prevent any leakage having an adverse environmental impact. The clean rainwater that will be discharged from the site is also not considered to be a hazardous substance.

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4 STAGE 2 – IDENTIFYING THE RELEVANT HAZARDOUS SUBSTANCES

4.1.1 Stage 1 identified a number of hazardous substances that are stored and used on site as part of site operations. Stage 2 requires a review of the listed substances to determine which are relevant hazardous substances (RHS). Each of the substances identified within Stage 1 is reviewed below, considering their chemical and physical properties and how they are stored and used on site, to determine the potential pollution risk of each hazardous substance. 4.1.2 RHS in relation to IED are defined as: those substances or mixtures defined within Article 3 of Regulations (EC) No1272/2008, which, as a result of their hazardousness, mobility, persistence and biodegradability (as well as other characteristics), are capable of contaminating soil or groundwater and are used, produced and/or released by the installation.

4.2 Diesel, Lubricating and Waste Oil 4.2.1 Diesel and lubricating are used by the engines as part of the site operations. Both are capable of contaminating soil and groundwater should they be released into the environment. These oil- based substances are toxic to the water environment and although they are biodegradable in particular conditions, larger volumes of these substances are likely to be relatively persistent in the environment. 4.2.2 Diesel is stored in sufficiently large quantities to be considered a RHS for the purposes of this assessment. 4.2.3 Lubricating oil will not be stored on the site, it will be brought onto the site as needed for maintenance purposes and waste oil will be removed from site as it is produced. On this basis lubricating oil and waste lubricating oil have been discounted as RHSs for the purposes of this baseline assessment of soils and groundwater.

4.3 Ethylene Glycol 4.3.1 Ethylene glycol is used as an additive in the closed loop cooling system for the engines. This may need topping up infrequently and in small volumes but will be brought to site on an as needed basis. There will be no onsite storage of ethylene glycol, it will only be present when diluted within the cooling system. The cooling systems for each engine are enclosed within the relevant engine container which will be located on concrete hardstanding. The potential for the substance to enter soil and groundwater is extremely limited. On this basis, ethylene glycol has been discounted as a RHS for the purpose of this baseline assessment of soil and groundwater.

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5 STAGE 3 – ASSESSMENT OF THE SITE-SPECIFIC POLLUTION POSSIBILITY

5.1.1 The RHSs identified in Stage 2 are to be considered in Stage 3 in the context of the site itself to determine whether circumstances exist which may result in the release of the substance in sufficient quantities to represent a pollution risk, either as a result of a singular emission or as a result of accumulation from multiple emissions. 5.1.2 Circumstances under which emissions may occur include: • Planned emissions; • Accidents and / or incidents; and • Routine operations. 5.1.3 The only planned emissions at the site are: • stack emissions, these were discounted at Stage 1 as they are not considered hazardous to soils and groundwater; • site discharge to the surface water network, this was discounted as a hazardous substance in Stage 1. 5.1.4 The site will have an Environmental Management System (EMS) which outlines the site’s procedures in place to minimise the frequency of accidents or incidents occurring and outlines procedures in place to minimise the risk in the event of an accident or incident occurring. These are summarised below: • All aspects of the site operations have been assessed for significance and an appropriate environmental risk assessment has been carried out; • Regular inspections (typically 2 in each 24-hr period) of impermeable surfaces, tanks, bunds and pipe work will be carried out and repairs and maintenance undertaken as necessary; • All plant and equipment will be inspected and maintained in accordance with legal requirements and the manufactures recommendations and maintenance records will be kept by site management; • Any complaints received about site activities will be recorded and investigated in accordance with complaints log and investigation procedure; • A mechanism will be in place to fully investigate any environmental incidents and non- conformances in both normal and abnormal conditions and to record any remedial actions that might be taken and how to prevent re-occurrence; • A site-specific emergency contingency and accident management plan will be in place; and • All relevant staff will receive environmental training relating to environmental best practice on induction and are required to follow safe working procedure. 5.1.5 Emissions as a result of the RHS used during routine operations are outlined in the sections below.

5.2 Diesel 5.2.1 The main top-up tank will be within a concrete bund with a capacity of 110% that of the tank. The belly tanks will be located within the engine container that it serves and each engine container will have capacity to store 110% of the contents a belly tank and be designed to be impervious to diesel. 5.2.2 The main top-up tank will be subject to daily visual checks for integrity and leaks. All tanks will be stored on an impermeable surface with sealed drainage to form a barrier and cut off the pathway

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to soil and groundwater. The surface will be regularly inspected as part of the EMS and will be repaired where necessary to maintain the impermeable nature of the site surface.

5.3 Site Specific Pollution Possibility 5.3.1 Given the management procedures in place at the site and the sealed drainage system, the RHS as a result of routine operations and RHS release as a result of accident and/or incident are considered to represent a low risk for the facility in terms of contaminating land or groundwater.

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6 STAGE 4 – PROVIDE A SITE HISTORY

6.1.1 The purpose of Stage 4 is to determine which of the RHS identified in Stage 3 have the potential to be present on site in the soil and groundwater already as a result of activities undertaken at the site to date and to determine whether they are coincident with potential future emission points.

6.2 General Site History 6.2.1 Historical mapping is available from 1871 and indicates that the site at that time was in agricultural use with a few buildings, as part of Buckhouse Farm. The surrounding land includes a brick works to the north west of the site and another brickworks a bit further from the site, to the south east. There is a railway line located further to the south / south east of the site. 6.2.1 The site is indicated to remain in agricultural use with little change until the 1909-1913 mapping where a clay pit and associated tramway are identified to the south east of the site. A small area of the clay pit crosses the south eastern border of the site and is located within the site boundary. 6.2.2 In the 1932-33 mapping, the clay pit now covers a larger portion of the assessment site and the tramway extends across more than half the length of the site. 6.2.3 In the 1956-61 mapping, the tramway has been moved and now crosses over the eastern corner of the site. Most of the clay pit is now shown as a pond. By 1965, the old clay pit area is a pond and there is no tramway located on the site. The Buckhouse Farm buildings are still present on the site, as is Holly Cottage (previously unlabelled), some drainage channels and a small pond. The north western brickworks is labelled as disused. The south eastern brick works is no longer present in the 1975-1976 mapping. 6.2.4 In the 1986-1988 mapping, the large pond is no longer present on the site (presumably infilled) and the disused brickworks to the north east has been replaced by a leisure sport complex. 6.2.5 The 1989-1993 mapping shows that the whole site is now taken over by some large unlabelled buildings (further research shows this was a Hewlett-Packard facility) and a small electrical substation. There are roads bordering three of the four borders of the site, one of which (Cain Road) appears unfinished. Cain Road has been finished in the 1993-1994 mapping, and leads to a roundabout, near which is the label “Amen Corner Business Park”. This layout of the site is present up to and including the 2020 mapping.

6.3 Previous Ground Investigations 6.3.1 Details of previous intrusive ground investigations are included in the following reports: 1. CBRE (October 2018) Phase II Geo-Environmental Assessment. Reference: 50BCD0262442/PII 2. Arcadis (July 2020) AWS Mini Region: Highland – Site Due Diligence. Reference: 10040272- SDD-RG12-001 6.3.2 These reports cover both the area of the proposed installation as well as the wider site. For the purpose of baselining the sites only results from these site investigations that are relevant to the proposed installation are provided in Section 9. 6.3.3 CBRE carried out ground investigation works at the site in July 2018. The investigation comprised 13 cable percussion boreholes to a maximum depth of 15.45 m below ground level (mbgl), and 18 window sample boreholes, to a maximum depth of 5.0 mbgl. The cable percussion boreholes were installed as combined gas and groundwater monitoring wells, with selected window sample boreholes also installed as ground gas monitoring wells. Sampling of perched groundwater was completed on one occasion, with ground gas monitoring carried out on six occasions. A total of 70 soil samples and eight perched groundwater samples were collected and scheduled for a suite of laboratory analysis appropriate to the known history of the site and field observations, including

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pH, metals, total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), volatile organic compounds (VOC), semi-volatile organic compounds (SVOC), polychlorinated biphenyl (PCB) and asbestos. General water quality parameters, including ammoniacal nitrogen, were also analysed within the perched groundwater samples taken. 6.3.4 During the Arcadis 2020 ground investigation, Arcadis carried out sampling of soil and groundwater, with selected samples submitted for chemical contamination testing. A generic suite of analysis was scheduled on soils based on the contamination risk identified in the Phase 1 environmental due diligence. Groundwater from the site was sampled via low flow monitoring on a return visit and a comprehensive suite of analysis was undertaken. 6.3.5 During these previous investigations there were no wide-spread, gross or potentially mobile contamination impacts identified at the site. The Arcadis 2020 report stated that, based on the measured contaminant concentrations, site soils and groundwater concentrations do not present a significant risk to human health under a commercial development scenario. 6.3.6 Asbestos was not recorded in soil samples analysed in previous investigations. However, a fragment of asbestos cement was recorded in Made Ground in one location during the 2018 CBRE investigation in the area of the historic clay pit. Considering the number of samples analysed during both investigations, this was not considered to be indicative of a larger problem in that area. Made Ground deposits in the southeast of the site, associated with the infilled former clay pit, were also found to be locally impacted with total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH). CBRE stated that the risk posed by these contaminants to future residential site users could be adequately mitigated through the incorporation of standard mitigation measures (e.g. use of suitable topsoil, incorporation of vapour protection measures locally and upgrading of water supply pipes). 6.3.7 A continuous shallow groundwater body was not identified during previous investigations. Perched groundwater was encountered at depths of between 0.4 m and 6.6 mbgl during the previous CBRE monitoring. Marginally elevated concentrations of metals and PAH were also recorded within samples of perched groundwater recovered from the southeast of the site. However, the concentrations recorded were not considered to be indicative of a significant impact and given the low sensitivity of the site with respect to controlled water receptors it was concluded that further action was not necessary. 6.3.8 Several contaminants were found in exceedance of assessment criteria protective of controlled waters (groundwater and surface water), however the risk to controlled waters was not indicated to be significant given the low sensitivity of the water environment at this site and the highly conservative nature of the GACs, which do not consider the effects of dilution and attenuation. The Arcadis 2020 report concluded that the risk to controlled waters is therefore considered low and no further work is likely to be warranted in this respect. 6.3.9 Elevated TPH concentrations that may pose a potential risk to new water supply pipes were recorded to the northeast of the site during the 2018 CBRE investigation. However, the new 6” water supply is proposed to enter the site to the northeast and will not intersect this area. 6.3.10 Groundwater strikes were recorded between 4.1 and 20.0 mbgl in BGS borehole logs relating to intrusive ground investigation works completed on site in 1989. 6.3.11 CBRE carried out ground gas monitoring in 2018 and recorded elevated concentrations of ground gases across this area. Gas monitoring was completed on six occasions. Readings were collected using a handheld infra-red gas analyser (GA5000) to measure methane, carbon dioxide, oxygen, hydrogen sulphide, carbon monoxide and gas flow rates as well as a PID to measure VOC. The preliminary gas assessment concluded that the site would fall into CIRIA ‘Characteristic Gas Situation 2’, i.e. ‘low’ risk and basic gas protection measures would be required within any proposed buildings on site.

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6.4 Potential Historic Contaminants 6.4.1 Pollution incidents listed in the 2020 Groundsure report within 500 m of the site are listed in Table 6-1 below: Table 6-1: Substantiated Pollution Incident Register

Date Location (relative Pollutant Significance to the site) 10/07/2003 138 m north west General biodegradable Water Impact: Category 4 (No Impact) materials and wastes Land Impact: Category 3 (Minor) Air Impact: Category 4 (No Impact)

12/08/2002 314 m north west Specific waste materials Water Impact: Category 4 (No Impact) Land Impact: Category 3 (Minor) Air Impact: Category 4 (No Impact) 18/04/2002 493 m south Inert materials and wastes Water Impact: Category 4 (No Impact) Land Impact: Category 3 (Minor) Air Impact: Category 4 (No Impact)

6.4.2 A review of the available information indicates a number of potential sources of historic contamination. However, the soils and groundwater on site are not considered to pose a significant risk to human health or controlled waters under a commercial development scenario, and therefore no remediation has been considered necessary.

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7 STAGE 5 – IDENTIFY THE SITE’S ENVIRONMENTAL SETTING 7.1 Site Setting and Sources of Desk Study Information 7.1.1 The following sections detail the environmental setting of the proposed installation. The sources of desk study information utilised in order to describe the condition of the installation, and in particular, to determine the potential for substances to be present in, on or under the land associated with present and past uses of the site and its surrounding areas are listed below: • Publicly available data sets from the EA, DEFRA, Coal Authority and Public Health England; • Ground investigation information derived from reports listed in Section 6.3.1; and • Information held by the British Geological Survey relating to geology and hydrogeology.

7.2 Topography 7.2.1 OS mapping indicates that the site is relatively level with an elevation of approximately 65.5 – 68 m above Ordnance datum (mAOD).

7.3 Geology 7.3.1 A summary of the geology of the site encountered during the previous Arcadis 2020 ground investigation is in Table 7-1 below. The CBRE Phase II report (2018) also identified Head Deposits in some areas of the site, including boreholes located within the proposed permit boundary. The Head Deposits were encountered at depths of 0.4 mbgl to 6.7 mbgl and at thicknesses ranging from 0.7 to 3.4 m. The other geology encountered within the CBRE 2018 Phase II investigation is consistent with that from the Arcadis 2020 ground investigation below. Table 7-1: Site Geology

Strata Minimum Maximum Description Aquifer depth depth Classification Made Ground 0.0 0.38 – Generally recorded as bituminous hardstanding n/a 8.50 or grass, overlying gravelly sand interpreted as (BH106) type 1 material. Fill material was recorded is BH103, BH105 and BH106 to depths of between 6.3 and 8.5m bgl. and was generally found to comprise soft sandy gravelly clay with fragments of rubble, brick, concrete, plastic and rare wood, overlying soft to firm greenish brown and blueish grey silt or sandy clay with brick, concrete and rare ceramic and glass fragments. Claygate 0.38 – 1.2 – 9.30 Firm brown clay interbedded with bands of fine Secondary A Member – 8.50 to medium orangish brown sand, recorded aquifer London Clay within the upper London Clay Formation strata. Formation (BH102 & BH106 only) London Clay 0.50 - 10.50 – Firm becoming very stiff brown mottled blueish Unproductive Formation 8.00 18.95 grey slightly silty slightly sandy clay with rare strata (base of disseminated pyrite, selenite and white shells boreholes) (5mm). Strata is described as closely fissured with occasional bands of grey mudstone at depth.

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Made Ground 7.3.2 General Made Ground comprising type 1 sand / gravel was recorded in the Arcadis 2020 investigation to a depth of between 0.38 to 0.60 mbgl. Deeper fill material was recorded in BH103 and BH105, to a maximum depth of 8.50 mbgl. 7.3.3 Obstructions including cobbles of brick and concrete were recorded within the fill material. Fill material recorded in BH103 also included rubble, brick, concrete and plastic waste. A terram membrane was also recorded at 0.47 mbgl in BH104 and the remnants of an old transformer block were noted within the hand pit of BH104. London Clay Formation 7.3.4 The London Clay Formation was recorded beneath the Made Ground across the site at depths of between 0.5 and 8.0 mbgl and was recorded to the base of all boreholes. No visual or olfactory evidence of contamination was present.

7.4 Hydrogeology 7.4.1 A continuous shallow groundwater body was not identified during previous investigations. Groundwater strikes were recorded during the Arcadis 2020 drilling between 0.6 and 4.0 mbgl. Resting groundwater levels were recorded between 1.21 and 3.44 mbgl (or 63.50 and 65.49 mAOD). Perched groundwater was encountered at depths of between 0.4m and 6.6mbgl during the previous CBRE monitoring and groundwater strikes were recorded between 4.1 and 20.0 mbgl during the 1989 Geotechnics drilling. 7.4.2 The Claygate Member indicated to be present locally in the northwest corner of the site is classified as a Secondary A aquifer with medium vulnerability. The underlying London Clay Formation is classified as unproductive strata and therefore has low vulnerability. Source Protection Zone 7.4.3 The site is not situated within a Source Protection Zone and therefore it is not considered that the underlying groundwater is a sensitive receptor.

7.5 Hydrology 7.5.1 Four surface water features were found within 250 m of the site. The nearest is an unnamed inland river, located 129 m north of the site boundary. Flood Risk 7.5.2 The EA’s Flood Map for Planning indicates that the site is located within Flood Zone 1, whereby the annual probability of flooding from fluvial or tidal sources is classified as less than 1 in 1,000. The site is considered to be of ‘very low’ risk from surface water, tidal and fluvial flooding.

7.6 Environmental Consents, Licences, Authorisations, Permits and Designations for the Site and Surrounding Areas Water Discharges and Abstraction Licences 7.6.1 Information from the EA website at the time of writing indicates that there is only one permitted discharge consent within 500 m of the site. The details are provided in Table 7-2 below:

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Table 7-2: Summary of Discharge Consents

Operator Permit Number Address Distance from Discharge postcode (km) type BHSE General TH/CASM.2674/001 Office Buildings at Peacock 0.4 Office Partner Ltd (Revoked 2008) Lane, Bracknell, Berkshire, buildings RG12 8SS

7.6.2 There is no publicly available information regarding water abstractions, however previous reports have stated that there are no licensed potable / non-potable groundwater abstractions within 2 km of the site and no surface water abstractions within 1.5 km of the site. Landfill Sites 7.6.3 Information from the Groundsure 2020 report indicates that there are no active or recent landfill sites within 500 m of the site. 7.6.4 The 2020 Groundsure report identified 5 known historical landfill sites within 500 m of the site, according to EA records, 3 landfill sites. The details are provided in Table 7-3 below. Table 7-3: Summary of Historical Landfill Sites

Operator Permit Number Address Distance Waste type Last from recorded postcode (m) input Not given Site reference: Beehive South 0 (on site) Industrial, 31/12/1983 54/12/4/38 West, Beehive commercial Road, Bracknell, Berkshire Easthampstead TG1/L/PRO001 Beehive North 0 (on site) Inert, Industrial, 31/12/1985 Rural District East, Beehive Commercial, Council Road, Amen Household, Corner, Liquid sludge Bracknell, Berkshire Not given Site Reference: Nike Land, 3 west Inert 31/12/1980 BRA4 Amen Corner Not given Site Reference: Rose Farm, 4 south west Inert 31/12/1985 BRA3 Amen Corner Not given Site Reference: Buckhurst 357 south Industrial Not given BRA24 Moors, Amen west Corner Not given Not given Public refuse tip 354 east Public refuse Not given Not given Not given Unit 47, 388 east Not given Not given Longshot Industrial Estate, Longshot Lane, Bracknell, RG12 1RL Not given Not given Public refuse tip 452 east Public refuse Not given

Waste Treatment or Disposal Sites 7.6.5 Information from the 2020 Groundsure report indicates that there are 4 historical waste sites, 1 licensed waste site (given as 4 iterations of the same permit in the Groundsure report) and 21 waste exemptions registered within 500 m of the site. The details are provided in Table 7-4 below.

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Table 7-4: Summary of Waste Activities (excluding exemptions)

Operator Permit Number Address Distance Type of site Date from postcode (m) Not given Not given Not given 57 east Historical Refuse 1980 Disposal Centre (B) Not given Not given Not given 268 east Historical Refuse 1973 Disposal Centre Not given Planning Refuse Disposal 387 east Historical Waste 26/05/2008 application: Centre, Management 07/00300/FUL Longshot Centre Industrial Estate, Longshot Lane, Bracknell, Berkshire, RG12 1RL Not given Not given Not given 492 south Historical Scrap 1994 west yard EA/EPR/FP3594SG S I T A Products 234 east Household, 28/04/1993 WML 83012 & Services Ltd, Commercial & (issued) Longshot Lane Industrial Waste CAS, Longshot T Stn Lane Ind. Est, Bracknell, Berks, RG12 1RL

Permitted Installations 7.6.6 Information from the EA website at the time of writing showed one permitted installation within 1 km of the site, details of which are provided in Table 7-5. Table 7-5: Summary of Installation Sites

Permit Permit Process Approx. Distance Holder Number (km) from the site Daler- BX7550IB Manufacturing using mercury or cadmium or any 0.7 Rowney compound of either element. Limited Inorganic chemicals; using mercury/cadmium and compounds if release into air.

Statutory Designated / Sensitive Receptors within 10 km 7.6.7 The nearest residential receptors are South View approximately 100 m to the south west of the site and Coves Farm Wood and Pocket Close approximately 100 m to the north of the site. In addition, there is an allocated and proposed residential development and care home on land north of Cain Road, approximately 20 m to the north of the site. 7.6.8 Table 7-6 below lists the statutory designated sites within 10 km of the site and sites of special scientific interest (SSSIs) or local nature sites (excluding local wildlife sites and ancient woodland) within 2 km. There are 22 local wildlife sites and 28 ancient woodlands within 2 km of the site. Table 7-6: Statutory Designated Sites

Site Name Designation* Location (relative to the site) Windsor Forest & Great Park SAC 9.2 km east Thursley, Ash, Pirbright & Cobham SAC 9.5 km south east

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Site Name Designation* Location (relative to the site) Thames Basin Heaths SPA 3.3 km south Wykery Copse SSSI 400 m south Farley Copse LNR 450 m north east Temple Copse LNR 1.2 km north east Jock’s Copse LNR 1.4 km north east Tinkers Copse LNR 1.5 km north east

* Special Area of Conservation (SAC); Site of Special Scientific Interest (SSSI); Special Protection Area (SPA); Local Nature Reserve (LNR); Local Wildlife Sites (LWS) 7.6.9 An assessment of ecological impacts resulting from operation of the facility has been made for the above designated sites. Mining 7.6.10 A search using the Coal Authority website indicated that, from the information currently available to the Coal Authority, the site is not located on a coal field. The search indicates that a coal mining search report is not recommended for this property. 7.6.11 Based on the above, the risk from coal mining at the site is considered to be low. COMAH 7.6.12 There are no COMAH sites recorded within 1 km of the site. Radon 7.6.13 According to the National Radiological Protection Board's Radon Atlases of England, Wales and Scotland at the time of writing, the site is within the lower probability radon area with less than 1% of homes estimated to be at or above the action level. Registered Radioactive Substances 7.6.14 Information on the EA website at the time of writing indicates that there are no radioactive substance users within 1 km of the site.

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8 STAGE 6 – SITE CHARACTERISATION

8.1.1 As detailed in Section 6, the installation site is located on a brownfield site situated within the area of a former clay pit. The installation site consists of an area comprising a former infilled clay pit and subsequently a Hewlett-Packard facility. The surrounding land use consists of previous brickworks as well as commercial, industrial and residential uses. The site is on the western edge of Bracknell town. 8.1.2 Section 7 confirms that the geology of the site comprises Made Ground and London Clay bedrock. Aquifer records show that the bedrock is classed as unproductive strata with a small area of Claygate Member which is designated a secondary A aquifer. The site does not lie in a groundwater Source Protection Zone or a nitrate vulnerable zone (NVZ). The nearest surface water feature, an unnamed river, lies at a short distance to the north of the site. 8.1.3 Previous pollution incidents from the substantiated incident register have been set out in Section 6.4. Field Evidence of Contamination 8.1.4 The previous ground investigation reports did not indicate any visual or olfactory evidence of contamination within the permit boundary area. Sensitivity of Water Environment 8.1.5 The sensitivity of the water environment is considered low; the site is not within a SPZ, there are no groundwater or surface water abstractions within 1km, the site is underlain by an unproductive bedrock aquifer and the nearest surface watercourse is approximately 130m to the north. Therefore, the risk to controlled waters from the marginal contaminant exceedances is considered to be low and unlikely to warrant further consideration.

8.2 Conceptual Site Model 8.2.1 The potential source-pathway-receptor linkages and associated risks upon completion of the proposed development at the site, as identified following in the Arcadis 2020 report, are summarised in the Conceptual Site Model (CSM) in Table 8-1 below. Table 8-1: Conceptual Site Model

Source Pathways Receptors Risk On site (current) Dermal contact & ingestion Human health (site users) Low Made Ground, Particulate / fibre / vapour inhalation Groundwater (secondary A Substation, Car parking Soil leaching / aqueous migration superficial aquifer) On site (historical) Dermal contact & ingestion Human health (site users) Low to Historic infilled ground, Particulate / fibre / vapour inhalation Groundwater (secondary A moderate Landfill, Made Ground, Soil leaching / aqueous migration superficial aquifer) Agricultural Off site (current) Vapour inhalation Human health (site users) Low Surrounding industrial Soil leaching / aqueous migration Groundwater (secondary A and commercial superficial aquifer) premises Off site (historical) Vapour inhalation Human health (site users) Low to Former tanks, Railway, Soil leaching / aqueous migration Groundwater (secondary A moderate Landfill superficial aquifer)

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9 STAGE 7 – SITE INVESTIGATION

9.1.1 As described in section 6.3 above no significant contamination was found in the area within the proposed permit boundary during the previous site investigations. Plans showing the locations of investigation boreholes and trial pits are at Figure 3 of the CBRE Phase II report (Appendix C) at Appendix F1 of the Arcadis 2020 report (Appendix D). 9.1.2 Boreholes BH105 and BH106 and window samples WS106 and WS107A (as referenced in the CBRE Phase II 2018 report at Appendix C) as well as boreholes BH101 and BH103 (as referenced in the Arcadis 2020 report at Appendix D) are located within or near to the proposed permit boundary. The logs for these boreholes are at Appendix C of the CBRE Phase II 2018 report and Appendix F2 of the Arcadis 2020 report. 9.1.3 The ground gas investigation results from the CBRE gas monitoring from the boreholes located on or near the installation site are provided in Table 9-1 below. Note that gas monitoring was not undertaken during the Arcadis 2020 ground investigation. Table 9-1: Ground Gas Results

Borehole Flow Methane Carbon Oxygen Hydrogen Carbon PID peak Reference (l/hr) (%v/v) dioxide (%v/v) sulphide monoxide (ppm) (%v/v) (ppm) (ppm) BH105 0 - 9.0 not 1.2 – 6.0 16.5 – not 3.0 – 6.0 0 – 4.3 (CBRE) detected 20.3 detected BH106 0 – 0.1 71.4 - 72.1 15.7 – 0.4 not not 0 – 5000+ (CBRE) 17.3 detected detected – 1.0 WS106 not not not not not not not (CBRE) recorded recorded recorded recorded recorded recorded recorded WS107 -0.1 - 0 not 0.4 – 0.8 20.2 - 21.9 not 0 – 12.0 0 (CBRE) detected detected

Note: Gas monitoring record sheets from only two monitoring rounds were present in the report provided to RPS. 9.1.4 The groundwater analysis results from the CBRE and Arcadis monitoring are provided in Appendix 2 and Appendix F5 respectively. The groundwater risk estimation from the Arcadis 2020 investigation is presented in Table 9-3 below. Table 9-2: Groundwater Risk Estimation (source: Arcadis 2020 report)

Receptor Soil samples with measured GAC No. Exceedance contaminant concentrations in (mg/kg) exceeding concentration excess of the GAC range (mg/kg) Human Health No contaminant concentrations above the GACs. Aquifers Copper: BH102 1 1 2.8 Lead: BH106 1.2 1 1.81 Nickel: BH102, BH106 4 2 10.3 – 18.8 Zinc: BH102 12.1 1 15.7 Aquifers and surface TPH: BH106 10 1 15 water

9.1.5 A summary of the findings of the chemical analysis for soils from the CBRE and Arcadis monitoring are provided in Appendix 2 and Appendix F5 respectively. The soil risk estimation from the Arcadis 2020 investigation is presented in Table 9-3 below.

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Table 9-3: Soil Risk Estimation (source: Arcadis 2020 report)

Receptor Soil samples with measured GAC No. Exceedance contaminant concentrations in excess of (mg/kg) exceeding concentration the GAC range (mg/kg) Human Health No contaminant concentrations above the GACs. Aquifers Benzo(b)fluoranthene: BH103 (0.5-0.8m), 0.026 5 0.297 – 2.42 BH105 (6.3-6.5m), BH106 (0.54m), BH106 (1.8-2m), SKIP sample Benzo(k)fluoranthene: BH103 (0.5-0.8m), 0.037 5 0.126 – 1.71 BH105 (6.3-6.5m), BH106 (0.54m), BH106 (1.8-2m), SKIP sample Benzo(g,h,i)perylene: BH103 (0.5-0.8m), 0.105 5 0.15 – 1.59 BH105 (6.3-6.5m), BH106 (0.54m), BH106 (1.8-2m), SKIP sample Indeno(1,2,3-c,d)pyrene: BH103 (0.5-0.8m), 0.022 5 0.194 – 2.18 BH105 (6.3-6.5m), BH106 (0.54m), BH106 (1.8-2m), SKIP sample Aquifers and Naphthalene: BH105 (6.3-6.5m), BH106 0.015 3 0.0318 – 0.126 surface water (1.8-2m), SKIP sample Benzo(a)pyrene: BH103 (0.5-0.8m), BH105 0.013, 5 0.251 - 2.3 (6.3-6.5m), BH106 (0.54m), BH106 (1.8- 0.0002 2m), SKIP sample

RPS Ground Investigation 9.1.6 A Phase 2 Geotechnical ground investigation will be undertaken by RPS in 2021. Where relevant, sections of this SCR will be updated with results from any further site investigations.

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10 STAGE 8 – PRODUCE A BASELINE REPORT

Ground Gas 10.1.1 A single elevated steady state gas flow reading was recorded at BH105 during CBRE’s second monitoring round (9.0l/hr). However, CBRE attributed this anomalous reading to the rapidly falling atmospheric pressure recorded during the second monitoring visit combined with the flooding of the response zone as a result of perched groundwater recharge following groundwater sampling completed the previous week. This was supported by the absence of significantly elevated gas flows on subsequent visits (maximum 0.7l/hr). No elevated steady state gas flow rates were recorded across the remainder of the site (i.e. all ≤0.1l/hr). 10.1.2 Elevated concentrations of VOC were recorded during the second and third rounds of ground gas monitoring (>5,000ppmV at BH106). However, no corresponding significant soil or perched groundwater sources of VOC have been identified at these locations, with no clear trend in significantly elevated PID results, suggesting that this may be attributable to instrument error. 10.1.3 Concentrations of carbon monoxide (up to 35ppmV) and hydrogen sulphide (≤1ppmV) were recorded above the instrument limit of detection during monitoring, though not at the locations within or near the permit boundary. Asbestos 10.1.4 Asbestos was not recorded in soil samples analysed; however asbestos cement was recorded in one location during the 2018 CBRE investigation in the area of the historic clay pit, which is close to the proposed installation site but the location (WS112) was not located within the proposed installation boundary. Considering the number of samples analysed during this and the previous investigation, this is not considered to be indicative of a problem requiring site wide mitigation measures. Polyaromatic Hydrocarbons 10.1.5 Within the soil samples, several PAHs were measured at concentrations exceeding the GACs for a commercial/industrial end use (Arcadis 2020). Note that the CBRE 2018 investigation used GACs for a residential end use. However, PAHs are known to be hydrophobic and do not readily dissolve in water. PAHs were not recorded above the method detection limit (MDL) in the groundwater samples analysed, confirming that they are not likely to be mobilised by leaching into the underlying aquifer or migrating to nearby surface waters and thereby are not likely to present a risk to these receptors. VOCs and SVOCs 10.1.6 Concentrations of BTEX, MTBE, SVOCs, VOCs, PCBs, chlorinated hydrocarbons, halogenated hydrocarbons, benzenes, herbicides/fungicides/pesticides were all measured below the laboratory MDL. TPH 10.1.7 In the CBRE Phase II 2018 investigation, moderately elevated concentrations of TPH (e.g. >1,000mg/kg) and PAH (e.g. >30mg/kg) were only recorded within the Made Ground recovered from the eastern area of the assessment site (including WS107A, which is located on or near the proposed permit boundary). The profile of TPH detected within the soils is predominantly within the heavy-end aromatic fractions (>EC21 to EC40) and generally correlates with the higher PAH concentrations recorded. PAH may be indicative of partial combustion and are suggested to relate to the black discolouration of MG deposits encountered across this area of the site.

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10.1.8 Where analysed TPH was generally recorded at very low concentrations in the Arcadis 2020 investigation. The maximum total TPH value was recorded at 110mg/kg in the soil sample from BH103 0.5-0.8m bgl and predominantly comprised heavy end aromatic hydrocarbons. 10.1.9 Concentrations of TPH fractions were generally measured below the MDL. A single concentration of C21 – C35 aliphatics was found above the MDL of 10μg/L, with a value of 15μg/L in the sample from BH106 (Arcadis), which is not located on or near the proposed permit boundary. PCBs 10.1.10 There were no detected concentrations in samples analysed for PCBs, therefore these are not considered to be contaminants of concern. Metal and Inorganics 10.1.11 Concentrations of various metals were measured at low levels above the MDL in the majority of soil samples analysed and in all of the groundwater samples analysed. 10.1.12 Within the groundwater samples, several metal concentrations were recorded in exceedance of the highly conservative GAC protective of surface watercourses. However, these exceedances are generally marginal and concentrations of metals in the soil samples were not found to be particularly elevated, therefore it is likely that this is representative of the local groundwater quality. Additionally, the nearest surface watercourse is approximately 130m away, and the effects of attenuation across this distance are not considered by the EQS values used as assessment criteria.

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11 OPERATIONAL SITE CONDITION REPORT

11.1 Operational Phase 11.1.1 This section will be updated once the facility becomes operational and will be maintained throughout the operational life of the facility.

11.2 Site Condition Report Summary

4.0 Changes to the activity Have there been any changes to the activity boundary? If yes, provide a plan showing the If yes, provide a plan showing the changes to the activity boundary. changes to the activity boundary.

Have there been any changes to the permitted activities? If yes, provide a description of the If yes, provide a description of the changes to the permitted activities changes to the permitted activities Have any ‘dangerous substances’ not identified in the Application Site Condition If yes, list them Report been used or produced as a result of the permitted activities? If yes, list them Checklist of 1. Plan showing any changes to the boundary (where relevant) supporting 2. Description of the changes to the permitted activities (where relevant) information 3. List of ‘dangerous substances’ used/produced by the permitted activities that were not identified in the Application Site Condition Report (where relevant)

5.0 Measures taken to protect land Use records that you collected during the life of the permit to summarise whether pollution prevention measures worked. If you can’t, you need to collect land and/or groundwater data to assess whether the land has deteriorated. Checklist of 1. Inspection records and summary of findings of inspections for all pollution prevention measures supporting 2. Records of maintenance, repair and replacement of pollution prevention measures information

6.0 Pollution incidents that may have had an impact on land, and their remediation Summarise any pollution incidents that may have damaged the land. Describe how you investigated and remedied each one. If you can’t, you need to collect land and /or groundwater reference data to assess whether the land has deteriorated while you’ve been there. Checklist of 1. Records of pollution incidents that may have impacted on land supporting 2. Records of their investigation and remediation information

7.0 Soil gas and water quality monitoring (where undertaken) Provide details of any soil gas and/or water monitoring you did. Include a summary of the findings. Say whether it shows that the land deteriorated as a result of the permitted activities. If it did, outline how you investigated and remedied this. Checklist of 1. Description of soil gas and/or water monitoring undertaken supporting 2. Monitoring results (including graphs) information

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12 SURRENDER SITE CONDITION REPORT

12.1.1 At permit surrender, the following sections of the SCR template (EPR H5) will be completed and submitted to the EA as part of the permit surrender application. Information that has been gathered over the lifetime of the Permit will be used to identify whether the land is in a satisfactory condition. If necessary, surrender reference data will be collected and remediation will be undertaken if required.

8.0 Decommissioning and removal of pollution risk Describe how the site was decommissioned. Demonstrate that all sources of pollution risk have been removed. Describe whether the decommissioning had any impact on the land. Outline how you investigated and remedied this. Checklist of 3. Site closure plan supporting 4. List of potential sources of pollution risk information 5. Investigation and remediation reports (where relevant)

9.0 Reference data and remediation (where relevant) Say whether you had to collect land and/or groundwater data. Or say that you didn’t need to because the information from sections 3, 4, 5 and 6 of the Surrender Site Condition Report shows that the land has not deteriorated. If you did collect land and/or groundwater reference data, summarise what this entailed, and what your data found. Say whether the data shows that the condition of the land has deteriorated, or whether the land at the site is in a “satisfactory state”. If it isn’t, summarise what you did to remedy this. Confirm that the land is now in a “satisfactory state” at surrender. Checklist of 1. Land and/or groundwater data collected at application (if collected) supporting 2. Land and/or groundwater data collected at surrender (where needed) information 3. Assessment of satisfactory state 4. Remediation and verification reports (where undertaken)

10.0 Statement of site condition Using the information from sections 3 to 7, give a statement about the condition of the land at the site. This should confirm that: 1. the permitted activities have stopped 2. decommissioning is complete, and the pollution risk has been removed 3. the land is in a satisfactory condition

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13 CONCLUSIONS

13.1.1 RPS has undertaken an assessment of the site condition at the proposed site for an emergency back-up generation facility for an Emergency Back-up Generator facility in Bracknell in support of an application for an environmental permit. The primary purpose of this report is to provide information to the Environment Agency in relation to the operations and to provide them with a framework against which potential future contamination issues will be assessed. 13.1.2 The published geology of the site indicates the bedrock geology under the site to be London Clay Formation. There is no published record of superficial deposits. Previous ground investigations identified Made Ground, Claygate Member in one area and London Clay Formation bedrock. The Claygate Member indicated to be present locally in the northwest corner of the site is classified as a Secondary A aquifer with medium vulnerability. The underlying London Clay Formation is classified as unproductive strata and therefore has low vulnerability. There is also an infilled historic clay pit in the south east of the site. 13.1.3 Diesel is the only RHS identified at the site. 13.1.4 The main diesel top-up tank will be within a concrete bund with a capacity of 110% that of the tank. The belly tanks will be within the relevant engine container which will each have capacity to store 110% of the relevant tank. 13.1.5 The diesel tanks are subject to daily visual checks (typically 2 times in a 24-hr period) for integrity and leaks. All tanks are stored on an impermeable surface with sealed drainage to form a barrier and cut off the pathway to soil and groundwater. The surface is regularly inspected as part of the EMS and will be repaired where necessary to maintain the impermeable nature of the site surface. 13.1.6 The previous ground investigations undertaken in 2018 and 2020 have not identified significant contamination within the area of the installation. The information from these investigations has been used to inform the baseline for the site presented within this report.

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DRAWINGS

Drawing 1 Location Plan Drawing 2 Proposed Permit Boundary Drawing 3 Drainage Plan Drawing 4 Statutory Designated Sites within 5 km

Drawing 5 EA Conservation Screening Report