Flood Risk Assessment

Poyle Quarry Western Extension, Berkyn Manor Farm, Berkshire Flood Risk Assessment

On behalf of

Project Ref: 35678/4001/02 Rev: B | Date: 3rd October 2017

Office Address: Caversham Bridge House, Waterman Place, Reading, Berkshire, RG1 8DN T: 0118 950 0761 E: [email protected] Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Document Control Sheet

Project Name: Poyle Quarry Western Extension, Berkyn Manor Farm, Berkshire. Report Title: Flood Risk Assessment Project Ref: 35678/4001 Doc Ref: 02/Rev B Date: 03 October 2017

Name Position Signature Date

Charlotte Prepared by: Assistant Engineer C Cullimore 03/10/2017 Cullimore

Reviewed by: John Pulsford Senior Associate J Pulsford 03/10/2017

Approved by: Richard Thomas Senior Consultant R Thomas 03/10/2017

For and on behalf of Peter Brett Associates LLP

Revision Date Description Prepared Reviewed Approved

Revisions following EA comments A 28/09/2017 CC JNP RHT and scheme alterations

B 02/10/2017 Revisions post client review CC JNP JNP

Peter Brett Associates LLP disclaims any responsibility to the Client and others in respect of any matters outside the scope of this report. This report has been prepared with reasonable skill, care and diligence within the terms of the Contract with the Client and generally in accordance with the appropriate ACE Agreement and taking account of the manpower, resources, investigations and testing devoted to it by agreement with the Client. This report is confidential to the Client and Peter Brett Associates LLP accepts no responsibility of whatsoever nature to third parties to whom this report or any part thereof is made known. Any such party relies upon the report at their own risk.

ii J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Contents

Executive Summary ...... v 1 Background ...... 1 1.1 Scope of Flood Risk Assessment ...... 1 1.2 Policy Context ...... 1 1.3 Planning Background ...... 2 1.4 Caveats and Exclusions ...... 2 2 Existing Site ...... 4 2.1 Site Description ...... 4 2.2 Topography ...... 4 2.3 Hydrological Context ...... 5 2.4 Flood Defences ...... 6 2.5 Geology and Hydrogeology ...... 6 2.6 Existing Drainage Arrangements ...... 6 3 Flood Risk Assessment ...... 7 3.1 Fluvial Flooding ...... 7 3.2 Flood Zone ...... 7 3.3 History of Flooding ...... 8 3.4 Surface Water (Pluvial) Flooding ...... 8 3.5 Reservoirs, Canals and Artificial Sources ...... 9 3.6 Groundwater Flooding ...... 10 3.7 RBWM Strategic Flood Risk Assessment (SFRA) ...... 10 3.8 EA Modelled Flood Levels ...... 11 3.9 Impact of Climate Change ...... 12 4 Proposed Development ...... 13 4.1 Proposed Development ...... 13 4.2 Vulnerability and the NPPF Sequential Test ...... 13 5 Flood Mitigation Measures ...... 14 5.1 Flood Risk to Site ...... 14 5.2 Flood Storage and Flow Routes ...... 14 5.3 Surface Water ...... 14 5.4 Flood Warning and Safe Access ...... 15 6 Residual Risk ...... 16 7 Conclusions ...... 17 7.1 Conclusions ...... 17

iii J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Tables Table 3.1: EA Product 4 modelled flood levels...... 12

Figures Figure 2.1: Site Boundary ...... 4 Figure 2.2: Hydrological Setting ...... 5 Figure 3.1: EA Flood Map...... 7 Figure 3.2: Historic Flood Map ...... 8 Figure 3.3: EA Surface Water Flood Map ...... 9 Figure 3.4: EA Risk of Flooding from Reservoirs map ...... 9 Figure 3.5: EA 1D Node Locations Map ...... 11

Appendices

Appendix A EA Pre-Application Advice Appendix B Site Location Plan Appendix C Topographical Survey Appendix D Proposed Development Plans Appendix E EA Product 4 Data Appendix F RBWM SFRA Figures

iv J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Executive Summary

This Flood Risk Assessment (FRA) has been prepared by Peter Brett Associates LLP (PBA) to accompany a full planning application for the proposed sand and gravel extraction with restoration to agricultural land for a site known as Poyle Quarry Western Extension, located west of Poyle and south of Colnbrook. The site is greenfield and covers an area of approximately 22 hectares (ha).

The development was originally granted planning consent in 2007 (Planning Reference 04/01716). The consent was renewed in 2011 (Planning reference 10/02804) to extend the implementation deadline. The consent has now lapsed. The previous assessment of flood risk has been taken into account.

In considering the proposals, the following key aspects have been considered;

. Vulnerability of the site to flooding from all sources;

. Protection of users of the new development;

. That there should be no increase in flood risk to third parties as a result of the development.

In accordance with the latest Environment Agency (EA) site specific Product 4 data, the site lies mostly within Flood Zone 1 ‘Low Risk’ of fluvial flooding, with some small areas in Flood Zone 2 ‘Medium Risk’ and Flood Zone 3a ‘High Risk’. The site and surrounding areas are shown to be at risk of reservoir flooding, however flooding from a reservoir breach is highly unlikely. The site does not appear to be at risk of canal or sewer flooding.

Groundwater ingress into the void may occur during the excavation and backfilling stages. This will be controlled as part of the overall water management during the works and this will minimise the risk.

The proposed land use is for sand and gravel extraction and subsequent restoration which is classified as ‘Water Compatible’ and ‘More Vulnerable’ development respectively. According to NPPF Technical Guidance Table 3, ‘More Vulnerable’ development (as the worst case land use) is considered acceptable in Flood Zones 1 and 2.

As the main quarry development is located in Flood Zone 1 and cannot be located elsewhere it satisfies the requirements of the Sequential Test.

Safe dry escape for employees is available at the 1 in 100 year flood event.

The FRA confirms that the development is safe and does not detrimentally affect third parties, in accordance with the objectives of the National Planning Policy Framework (NPPF).

v J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

vi J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

1 Background

1.1 Scope of Flood Risk Assessment

1.1.1 This Flood Risk Assessment (FRA) has been prepared by Peter Brett Associates LLP (PBA), on behalf of our client, Summerleaze Ltd, to support a full planning application for the proposed sand and gravel extraction with restoration to agricultural land at the Poyle Quarry Western Extension site in between the villages of Poyle to the east and Colnbrook to the north near Slough, in Berkshire.

1.1.2 This application includes a short section of the quarry access road on the west side of Colne Brook. The remainder of the access route is covered in a separate FRA (ref. 35678/4001/003, PBA, September 2017).

1.1.3 The site lies to the west of the Colne Brook and Poyle Channel, which forms part of the wider Lower Colne system of interlinked watercourses and drainage channels, all flowing generally from north to south. A watercourse called the Horton Drain lies on the eastern boundary of the main extraction site. This watercourse has a limited upstream catchment. Horton Brook is located about 600m to the west of the site.

1.1.4 The FRA focuses on assessing the practical flood risk issues at the site as follows:

 Identification of all the potential sources of flooding at the site from all sources (i.e. fluvial, pluvial, groundwater, surface water);

 Assessment of the existing flood risk at the site and the potential impact of the proposals;

 Consideration of the flood risk implications, taking into account the potential allowance for climate change over the lifetime of the development, and the identification of the measures to mitigate flood risk.

1.2 Policy Context

1.2.1 This FRA has been prepared in accordance with the relevant national, regional and local planning policy and statutory authority guidance as follows:

 National policy regarding flood risk as contained within the National Planning Policy Framework (NPPF) March 2013 and the Planning Practice Guidance (PPG) ‘Flood Risk and Coastal Change’ (March 2014) and updated April 2015, and the ‘Flood risk assessments – climate change allowances’ guidance (February 2016);

 Local planning policy contained within the ‘Royal Borough of Windsor and Maidenhead (RBWM) Local Plan’. RBWM’s Development Plan Policy Schedule of the 27th September 2011 confirms that their Local Plan Policy F1 ‘Development within Areas Liable to Flood’ is still current.

 Policy F1 is supported by RBWM’s ‘Interpretation of Policy F1 (Development within Areas Liable to Flood)’, adopted as Supplementary Planning Guidance in May 2004;

 The Royal Borough of Windsor and Maidenhead Level 1 Strategic Flood Risk Assessment (SFRA), updated June 2017;

 The Royal Borough of Windsor and Maidenhead Preliminary Flood Risk Assessment (PFRA) May 2011.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 1

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

1.3 Planning Background

1.3.1 The site has a long and complex planning history. Further information on this is contained within the overall planning application documentation and is not repeated within this report, however for the purposes of assessing flood risk the relevant background is that an FRA, prepared by PBA was submitted as part of the original 2004 application (Berkyn Manor Farm Flood Risk Assessment, November 2004, Reference 14487/001). This FRA concluded, after undertaking additional hydraulic modelling, that there were no significant impacts on flood extents or flood levels in the area. This conclusion was accepted by the Environment Agency (EA).

1.3.2 The 2010 renewal application utilised the previous consented information, i.e. the flood risk was not re-assessed at that point.

1.3.3 It should be noted that since the original work, the EA have undertaken a comprehensive re- assessment of the hydraulic model for the Lower Colne system, including the Colne Brook, Poyle Channel and Horton Brook. This has resulted in a significant reduction in the modelled flood extents at the site such that the main gravel extraction site is within Flood Zone 1 (Low risk of fluvial flooding) and only the site access crosses local areas at higher risk of flooding.

1.3.4 Pre-application advice was sought from the EA for the wider application. The advice, dated 13 August 2017, is contained with Appendix A . The EA suggested the following points are addressed:

 Confirm the expected lifespan of the development

 Clarify the red line boundary and the route of the access track

 Clarify the existing structures across Colne Brook and confirm any new sections of track

 The use of 20% allowance for climate change is considered to be acceptable.

1.3.5 These points have been addressed within this FRA. There are detailed plans of the proposals contained within Appendix D and the lifespan of the development is stated within Section 4.

1.4 Caveats and Exclusions

1.4.1 This FRA has been prepared in accordance with the NPPF and Local Planning Policy. The proposed flood management and surface water management strategies are based on the relevant British Standards (BS8533), the standing advice provided by the EA or based on common practice.

1.4.2 The revised Construction (Design and Management) Regulations 2015 (CDM Regulations) came into force on April 2015 to update certain duties on all parties involved in a construction project, including those promoting the development. One of the designer’s responsibilities is to ensure that the client organisation, in this case Summerleaze Ltd, is made aware of their duties under the CDM Regulations.

1.4.3 The approach for the FRA and proposals for the surface water management strategy are based on the requirements of the EA where appropriate.

1.4.4 The EA Product 4 data on which the FRA is based is valid under a 12 month Licence. As such, the FRA is accurate at the time of issue but we would recommend the end user reviews the validity of the flood data on an annual basis with the EA.

1.4.5 PBA do not warrant that the advice in this report will guarantee the availability of flood insurance either now or in the future.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 2

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

1.4.6 The findings of this FRA are based on data available at the time of the study and on the subsequent assessment that has been undertaken to date. They relate to development proposals as outlined in Section 4.1.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 3

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

2 Existing Site

2.1 Site Description

2.1.1 The Poyle Quarry site is located within the Royal Borough of Windsor and Maidenhead. The total area of the site is approximately 22 hectares (ha) with the proposed quarry site covering an area of 20 hectares. The site is centred at OS Grid Reference 502,160mE, 176,430m N and the detailed site location plan, produced by PleydellSmithyman, dated August 2017, has been included in Appendix B.

2.1.2 The proposed western quarry extension site is currently occupied by agricultural land. To the north lies the village of Colnbrook, to the east lies the Colne Brook and the Eric Mortimer Rayner Memorial Lakes and to the south and west respectively is Berkyn Manor Farm and the Jayflex Aggregates quarry.

2.1.3 The proposed western quarry extension access corridor follows the boundary of the Eric Mortimer Rayner Memorial Lakes to the existing ‘Bailey’ bridge, over the Colne Brook.

2.1.4 The proposed western quarry extension boundary and access corridor route is shown in Figure 2.1.

Figure 2.1: Site Boundary

‘Bailey’ Existing Plant Proposed Bridge Site western quarry extension site

Proposed Access Corridor

Contains Ordnance Survey data © Crown copyright and database right 2013

2.2 Topography

2.2.1 A topographical survey drawing, produced by SLR, dated October 2015, is included as Appendix C.

2.2.2 The survey indicates ground levels vary across the western quarry extension site typically between an elevation of approximately 19.2m AOD at the south-western boundary of the western quarry extension site, rising to 19.9m AOD at the north-eastern boundary.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 4

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

2.2.3 The eastern (left bank) abutment of the ‘Bailey’ bridge is at a level of 21.0m AOD. The ‘Bailey’ bridge crosses the Colne Brook and the deck is at a level of 21.3m AOD. On the western side, the track levels drop from the ‘Bailey’ Bridge to 20.7m AOD and fall to 19.2m AOD locally north of the Eric Mortimer Rayner Memorial Lakes and at the western extent of the access route, matching the adjacent ground levels.

2.3 Hydrological Context

2.3.1 The site is surrounded by a number of reservoirs and lakes and interconnected watercourses as shown in Figure 2.2.

Figure 2.2: Hydrological Setting

Old Slade Lake

Orlitts Lake

Horton Brook

The Queen Mother Reservoir Colne Brook Poyle Horton Drain Channel

Eric Mortimer Rayner Memorial Lakes

River Colne Wraysbury Reservoir

Contains Ordnance Survey data © Crown copyright and database right 2013

2.3.2 The proposed access track heads west from the Colne Brook and runs to the north of the Eric Mortimer Rayner Memorial Lakes, located adjacent to the eastern boundary of the western quarry extension site.

2.3.3 The Queen Mother Reservoir is located 750m to west of the Western Quarry Extension site and covers an area of 192ha. The Wraysbury Reservoir lies approximately 600m to the southeast of the site and covers an area of 205ha.

2.3.4 The Horton Brook runs north to south before flowing west towards Horton. This lies to the west of the Western Quarry Extension site. The Horton Drain lies on the eastern boundary of the western quarry extension site.

2.3.5 The Colne Brook flows past the main extraction site approximately 200m to the east from north to south, where the Poyle Channel joins it, before meandering through a network of lakes to the south of the site and outfalls into the River Thames 4km to the south. The Orlitts and Old

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 5

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Slade Lakes lie approximately 1.5km to the northeast of the site and take water from the Colne Brook.

2.4 Flood Defences

2.4.1 Reviewing the available information on the EA’s website, the EA’ s site specific Product 4 flood data, it was found that there are flood defences on both banks of the Colne Brook and Poyle Channel providing a design standard of protection of 100 and 80 years respectively (see Appendix E for Product 4 data). These are shown to consist of ‘high ground’ formed within the natural bank of the channels.

2.5 Geology and Hydrogeology

2.5.1 A review of the bedrock geology of the site has been undertaken on the British Geological Survey (BGS) website (www.bgs.ac.uk). A review of the 1:50,000 scale bedrock geology maps indicated that the site is underlain by “London Clay Formation – clay, silt and sand, formed 34 to 56 million years ago during the Palaeogene Period.” overlain with superficial deposits as “Shepperton Gravel Member – sand and gravel, formed up to 2 million years ago during the Quaternary period.”

2.5.2 A review of the surface geology was undertaken using Cranfield University’s “Soilscapes” map (www.landis.org.uk/soilscapes). It was recorded that the site is underlain by “freely draining slightly acid loamy soils.”

2.5.3 A ‘Report on Groundwater Control and Mitigation’ was produced by Peter Brett Associates LLP, dated September 2017, to assess the groundwater conditions of the area and mitigation measures.

2.5.4 The Royal Borough of Windsor and Maidenhead SFRA confirms that the region is underlain by London Clay.

2.5.5 A review of the EA’s groundwater vulnerability maps, accessed on the EA’s website (www.environment-agency.gov.uk) highlighted the area covering and surrounding the site to be a “Principal aquifer” – these are “layers of rock or drift deposits that have high intergranular and/or fracture permeability. They may support water supply and/or river base flow on a strategic scale.”

2.6 Existing Drainage Arrangements

2.6.1 The site is currently used as agricultural land with no impermeable areas.

2.6.2 The site is traversed by several small land drains that form a part of the normal agricultural drainage for the land. Due to the nature of the underlying geology of the site, it is assumed that infiltration into the ground below is an important drainage pathway.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 6

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

3 Flood Risk Assessment

3.1 Fluvial Flooding

3.1.1 Fluvial flooding refers to flooding from rivers, resulting from overtopping of banks or breach of defences.

3.2 Flood Zone

3.2.1 The EA’s online Flood Zone mapping provides an initial indication of the probability of fluvial or tidal flooding to an area, which is refined by the use of more detailed site-specific level survey and modelled flood levels. The ‘Detailed Flood Map’ provided within the EA site specific Product 4 data is shown in Figure 3.1 and contained in Appendix E.

Figure 3.1: EA Flood Map

3.2.2 Figure 3.1 shows that the western quarry extension site lies predominately within Flood Zone 1 (no shading on Figure) which is assessed as having “less than a 1 in 1000 (0.1%) annual probability of fluvial flooding.” A small area on the southeast border of the western quarry extension site lies within Flood Zone 2 (light blue shading) which is assessed as having “between a 1 in 100 and 1 in 1,000 (1% - 0.1%) annual probability of fluvial flooding.”

3.2.3 Figure 3.1 also shows that the proposed access corridor west of the Colne Brook passes through two small areas within Flood Zone 2 (light blue) and between these a small area of Flood Zone 3a, labelled as defended. Flood Zone 3 is assessed as having “a 1 in 100 (1%) or greater annual probability of fluvial flooding.”

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 7

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

3.3 History of Flooding

3.3.1 The provided EA historic flood data shows that a small area at the east of the western quarry extension site was impacted by the flood events of 2003 (see Figure 3.2). This area appears not to be continuous with the Colne Brook or the Horton Drain which are the closest watercourses. Areas surrounding the site are shown to have experienced broader extents of flooding from the same event.

3.3.2 The 2014 event which was generally of greater magnitude than 2003 did not affect the site.

Figure 3.2: Historic Flood Map

3.4 Surface Water (Pluvial) Flooding

3.4.1 The “Surface Water Flooding Risk” map accessed on the EA’s website indicates areas within the site fall between “very low and high” risk of surface water flooding, however, only very minor areas are at “high” risk. These areas are shown in Figure 3.3. The flooding shown would occur following heavy rainfall, however given the existing agricultural nature of the land use and the presence of land drainage associated with this land use, the high risk areas are likely to be associated with local low points in the topography.

3.4.2 As the site will be excavated in phases for gravel extraction and de-watered during this process by pumping to control groundwater, surface water flooding is not a significant risk.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 8

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Figure 3.3: EA Surface Water Flood Map

3.5 Reservoirs, Canals and Artificial Sources

3.5.1 The “Risk of Reservoir Flooding” map available on the EA website has been reviewed as part of this assessment. The proposed development is shown to lie within the flood zones in the event of a breach of the Wraysbury Reservoir to the south and the Queen Mother Reservoir, as shown in Figure 3.4.

Figure 3.4: EA Risk of Flooding from Reservoirs map

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 9

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

3.5.2 In the event of such flooding, a large area covering the entirety of the site could be affected by water depths of over 2m. It should be emphasised that the risk of flooding from reservoir breach is very small in any case; the EA are the enforcement authority for the Reservoirs Act (1975) and all large raised reservoirs are inspected and supervised by reservoir panel engineers.

3.5.3 The nearest canal is the Grand Union Canal Slough Arm, located approximately 3.15km to the north of the site and flowing from west to east before outfalling into the Grand Union Canal. The site is not at significant risk of canal flooding.

3.6 Groundwater Flooding

3.6.1 Groundwater flooding is caused when groundwater permeates above existing ground level (i.e. where the water table meets the ground surface). This often occurs following prolonged periods of above average rainfall and can last for weeks and tends to happen in late winter when the water table is at its peak.

3.6.2 A review of the solid geology of the site indicates that the site is underlain by the London Clay formation, comprising clay, sand and silt. The overlying superficial soils are mainly sand and gravel of the Shepperton Gravel Member, described as “freely draining slightly acid loamy soils”, which in turn means rainfall is absorbed and allowed to drain through to underlying soils (information obtained from www.magic.gov.uk).

3.6.3 In accordance with the EA’s “Groundwater Vulnerability” map, the area covering and surrounding the site is shown to be underlain by a “Principal” aquifer – “layers of rock or drift deposits that have a high intergranular and/or fracture permeability” – may support water supply and/or river base flow on a strategic scale

3.6.4 As the proposal is for the extraction of gravels partly from below the groundwater table, groundwater ingress into the void is a pertinent issue for the operational phase. Groundwater control will form part of the water management plan for the development.

3.6.5 The local and regional impact on groundwater levels and flows is the subject of other studies that form part of the application ‘Poyle Quarry Groundwater Control and Mitigation Report’ (PBA March 2017).

3.7 RBWM Strategic Flood Risk Assessment (SFRA)

3.7.1 The RBWM Strategic Flood Risk Assessment (SFRA) was updated in June 2017 and provides flood risk information on a borough-wide scale. The mapping that accompanies the SFRA was updated in May 2017.

3.7.2 The SFRA information of specific relevance to the site is as follows:

 SFRA Figure 11 Flood Zone Map indicates the majority of the site in in Flood Zone 1, however the south and southwest of the site is within Flood Zone 3b.

 SFRA Figure 20 Climate Change map indicates the area south east of the site is located within Flood Zone 3a with an allowance for climate change.

3.7.3 Figure 11 and Figure 20 are not in agreement and the flood extents will be reviewed in Section 3.8 below against the EA data. The SFRA figure is included as Appendix F.

3.7.4 The SFRA indicates that surface water flooding, groundwater flooding and the overloading of the sewer system capacity, resulting in surcharging, are amongst the known problems within the borough.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 10

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

3.7.5 The SFRA indicates significant flooding within the Borough has occurred 10 times over the last 100 years, with the most recent events occurring in 2003 and 2007. The EA site specific Product 4 data confirms that an area of flooding occurred in 2003 on the site.

3.7.6 The previously mentioned SFRA indicates a known risk of groundwater flooding within the River Thames catchment due to the presence of the highly permeable soils, known as ‘Thames Gravels’, beneath the floodplain. The topic of groundwater is covered in detail elsewhere within other studies that form the planning application.

3.8 EA Modelled Flood Levels

3.8.1 In addition to confirming the flood zone classification, the EA’s Product 4 data provided the modelled flood levels for four different scenarios in the area of the site (see Appendix E).

3.8.2 There are several modelled in-channel data points (nodes) available on the eastern side of the site in the Colne Brook and the Horton Drain, the latter being on the eastern boundary of the site. For the purpose of this assessment, the following nodes have been used (circled in black on Figure 4.2):

 Colne Brook node to the north-east of the site (Node G095) which is representative for the section of the access track from the east up to the point it turns south to run parallel to the Colne Brook on the eastern (left bank) side. as it is upstream of this section.;

 Colne Brook nodes G094 at the upstream end and G092U at the downstream end at the Bailey Bridge crossing for the length of the access as it passes alongside the watercourse and;

 The Horton Drain nodes POYHD01 at the upstream end and POYHD005 at the downstream end for the main site.

Figure 3.5: EA 1D Node Locations Map

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 11

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

3.8.3 Table 3.1 below shows the EA modelled flood levels for the various scenarios.

Table 3.1: EA Product 4 modelled flood levels

Return Period (1 in …years) Flood Levels (m AOD)

G095 G094 G092U POYHD01 POYHD05

1 in 20 (5%) 19.55 19.54 19.53 18.97 18.95 1 in 100 (1%) 19.87 19.85 19.83 19.01 18.99 1 in 100 (1%) plus 20% 19.95 19.93 19.90 19.05 19.04 allowance for climate change 1 in 1000 (0.1%) 20.00 19.98 19.95 19.08 19.07

3.8.4 A comparison of the flood levels in the above table and the lowest existing ground levels of 19.20m AOD on the western quarry extension site, discussed in Section 2.2, demonstrate that up to and including the 1 in 1000 year (0.1% per annum) event, the main site is not susceptible to fluvial flooding.

3.8.5 There is very little variation in peak flood level for each return period for the Colne Brook along the length of the access and examining these flood levels and comparing them with the ground level confirms that parts of the access track west from the Bailey bridge to the main site could be flooded from the 20 year event although this area is shown as defended on the EA Flood Zone map.

3.9 Impact of Climate Change

3.9.1 In considering flood risk to the site, it is necessary to fully consider the potential impacts of climate change for the lifetime of the development within the mitigation measures.

3.9.2 In February 2016 the EA released new guidance on the allowances for climate change in Flood Risk Assessments: https://www.gov.uk/guidance/flood-risk-assessments-climate-change- allowances.

3.9.3 The guidance provides new contingency allowances for potential increases in peak river flow in Table 1, and for potential increases in peak rainfall intensity in Table 2.

3.9.4 Whereas the potential impacts of climate change in peak river flow were previously based on a uniform +20% increase over the next 100-year period, the new guidance provides a matrix of figures based on location (River Basin District), flood zone, land use and proposed lifespan.

3.9.5 The site lies within the Thames River Basin district and is mostly within Flood Zone 1, with some small areas in Flood Zones 2 and 3a, however these only affect the access track to the west of the Colne Brook. The quarrying of sand and gravel is classed as ‘Water compatible’ and waste operations as ‘More vulnerable’.

3.9.6 For Flood Zone 1 the guidance does not recommend any specific allowance to be added and for the worst case of Flood Zone 3, ‘More vulnerable’ land use and a time horizon of 2020’s (2015 to 2039, the shortest given in the guidance) allowances of higher central (+15%) and upper end (+25%) are recommended.

3.9.7 As noted in Section 1.34, the EA pre-application advice states that an allowance of 20% is considered acceptable.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 12

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

4 Proposed Development

4.1 Proposed Development

4.1.1 The proposed development includes the extraction of sand and gravel from the Poyle Quarry Western Extension site with the importation of inert fill and restoration to agricultural land using stockpiled topsoil. It is proposed to work the quarry in dry conditions and therefore de-watering using pumping is proposed.

4.1.2 Processing of the extracted materials will be undertaken at an existing processing facility to the north of the existing access track, south of Cottesbrooke Close. This element is not covered within this FRA.

4.1.3 An access corridor will be constructed from existing the ‘Bailey’ bridge crossing of the Colne Brook to the western quarry extension site.

4.1.4 The work will be phased with progressive working in five phases, working from north to south with a sequence of topsoil stripping, gravel extraction, backfilling with imported fill and then topsoil restoration and landscaping.

4.1.5 Soil materials stored on site for re-use will be stockpiled on the western and northern boundaries.

4.2 Vulnerability and the NPPF Sequential Test

4.2.1 The NPPF follows a sequential risk-based approach in determining the suitability of land for development in flood risk areas, with the intention of steering all new development to the lowest flood risk areas.

4.2.2 NPPF technical Guidance and PPG Table 2 confirms the ‘Flood risk vulnerability classification’ of a site, depending upon the proposed usage. This classification is subsequently applied to Table 3 to determine whether:

 The proposed development is suitable for the flood zone in which it is located, and;

 Whether an Exception Test is required for the proposed development.

4.2.3 The proposed development is classed as ‘Water-Compatible Development’ (Sand and gravel working) or ‘More Vulnerable’ (Landfill and sites used for waste management). The latter is the more sensitive land use.

4.2.4 The detailed analysis within the FRA confirms that the proposed development is mostly within Flood Zone 1 ‘Low Probability’, with the access corridor from the ‘Bailey’ bridge west of the site crossing very small areas of Flood Zone 2 ‘Medium Probability’ and Flood Zone 3 ‘High Probability’. Table 3 confirms such development is acceptable within these zones.

4.2.5 The overall proposals have previously been consented although the consent has now lapsed. The main site is within Flood Zone 1 and therefore satisfies the requirements of the Sequential Test.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 13

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

5 Flood Mitigation Measures

5.1 Flood Risk to Site

5.1.1 As discussed in Section 3.8 the potential risk of direct fluvial flooding of the western quarry extension site is negligible because the ground levels at the site are higher than the modelled flood levels up to the 1 in 1000 year (0.1% per annum) event. There will be an unworked margin left on the site boundary that will maintain a strip of high ground between the watercourse and the main excavation to maintain the existing standard of protection against direct fluvial flooding during the operational and restoration phases.

5.1.2 Groundwater management will form part of the overall quarry operation management plan and will include de-watering pumping during the excavation and backfilling stages.

5.1.3 The access corridor will be vulnerable to flooding during extreme events, however given the short term nature of the operations these are unlikely to occur during the extraction and backfilling phase of the quarry life.

5.1.4 If this does occur the quarry operations will stop for the duration of the event or until the access corridor is available. This has no impact on others.

5.2 Flood Storage and Flow Routes

5.2.1 The main site is unaffected by fluvial flooding and therefore there will be no impact on fluvial flood storage or flow routes during any stage of the works.

5.2.2 The access corridor will be constructed with a finished level to match the existing levels and bridge crossing of the Colne Brook is existing; therefore, they also will have no impact on flood storage and flow routes.

5.3 Surface Water

5.3.1 The operational phases of the quarry operation will require the control of all incoming water from either direct rainfall or groundwater. Therefore, the production of an operational phase water management plan is anticipated with pumped de-watering of the excavation from sumps and discharge to recharge trenches.

5.3.2 In accordance with the requirements of Part H3 of the Building Regulations 2010 and the sustainable drainage (SuDS) hierarchy of drainage techniques, it is preferred that surface water be discharged by one of the following listed in order of priority:

1. Infiltration to the ground 2. Discharge to a watercourse 3. Discharge to a sewer

5.3.3 The dewatering of the operational phases of the quarry, including groundwater and incoming surface water and the discharge of this into recharge trenches, see Appendix D, in effect complies with the first option above and satisfies the SuDS hierarchy.

5.3.4 The proposed development does not propose any impermeable area on the site because the processing of the gravels will take place off site.

5.3.5 After restoration of the quarry back to agricultural use at approximately the same ground profile and the re-use of soils stripped from the land prior to extraction, the run-off characteristics will be the same.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 14

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

5.4 Flood Warning and Safe Access

5.4.1 A flood forecasting and warning service is under the operation of the EA for areas at risk of flooding from rivers or the sea. Forecasts made rely upon direct measurements of rainfall, river levels, tide levels, predictive modelling systems, rainfall radar data and information provided by the Met Office. This service operates 24 hours a day, 365 days a year.

5.4.2 The proposed development will employ a minimal number of people on site, mainly plant operators and there would be no permanent accommodation on the site. The site itself could continue to operate during a flood as it is not directly affected by fluvial flooding. However, the access corridor would be affected. On receipt of a flood warning that may affect the safe access to and from the site, operations will be suspended and all staff will leave the site until it is safe to return.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 15

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

6 Residual Risk

6.1.1 It is not always possible to completely guard against flooding since extreme events greater than the design standard event can always occur, however, in this situation the risk is negligible due to the freeboard above predicted flood levels and the relatively short term nature of the works.

6.1.2 The risk is also dependant on the proposed land use. Developments such as a sand and gravel quarry and inert landfill with no permanent or fixed structures, fixed plant or inhabited buildings are low risk development because the consequences of a flood affecting the site only affects the operators and no third party receptors.

6.1.3 As the western quarry extension site is unaffected by flooding up to greater than the present day modelled 1 in 1000 year (0.1% per annum) probability event; if an extreme event exceeding this probability during the lifetime of the quarry operation and backfilling did occur the impacts would be minimal, therefore no additional measures are required to be taken.

6.1.4 A surface and groundwater water management strategy will be developed in accordance with the overall proposed mitigation plan, detailed in ‘Report on Groundwater Control and Mitigation’ and shown on Figure 5 contained in Appendix D.

6.1.5 As such, the residual risk is considered acceptable for the lifetime of the development.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 16

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

7 Conclusions

7.1 Conclusions

7.1.1 The site is located to the west of Colne Brook and the Poyle Channel. The Horton Drain lies on the eastern boundary of the main site. The area in which the site lies is defended by high ground as part of the Lower Colne Improvement Scheme.

7.1.2 There is no previous record of significant flooding at the site.

7.1.3 The Environment Agency Product 4 data confirms that the proposed main development lies within Flood Zone 1 ‘Low Probability’. There are some small areas of the access corridor that lie in Flood Zone 2 ‘Medium Probability’ and Flood Zone 3a ‘High Probability’, however these are shown as defended to the 1 in 100 year event.

7.1.4 The Environment Agency surface water risk map shows a small part of the site being at varying risk of surface water flooding. Due to the nature of the development (gravel extraction) and the need to lower and control groundwater levels during the excavation and backfilling phases surface water flooding is not a significant risk

7.1.5 Groundwater ingress into the void may occur during the excavation and backfilling stages. This will be controlled as part of the overall water management during the works and this will minimise the risk.

7.1.6 Following reviews of the information available, the site does not appear to be at significant risk of reservoir or canal flooding. The site and surrounding areas are shown to be at risk of reservoir flooding from the Wraysbury and Queen Mother Reservoirs, however flooding from a reservoir breach is highly unlikely.

7.1.7 The activities proposed are ‘Water compatible’ development during the gravel extraction phase and ‘More vulnerable’ during the waste management phase (the two will overlap). According to PPG Table 3, ‘Water Compatible’ development is considered acceptable in all flood zones and ‘More vulnerable’ in Flood Zones 1, 2 and 3a, subject to the Exception Test being satisfied for Flood Zone 3a. The development cannot be located elsewhere and the principle of development has been accepted previously as part of previous consents and therefore the Sequential Test is passed.

7.1.8 There are no flood flow or flood storage impacts arising from either the quarrying, the access corridor route or the landfill and restoration phases of the development.

7.1.9 Due to the short term nature of the development the potential impact of climate change on fluvial flood risk is not a significant issue. The impact of climate change on long term peak rainfall will not be a significant factor as the land will be restored to the same profile and land use as the pre-quarrying conditions.

7.1.10 Safe access and egress for operatives and staff is available for the lifetime of the development in combination with flood warning using the existing access track.

7.1.11 In summary, the development is considered safe and appropriate within the context of the NPPF, the PPG and Local Plan policies and has no detrimental impact on others.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 17

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 18

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Appendix A EA Pre-Application Advice

EA Pre-Application Advice Letter, dated 13 August 2017, reference ENVPAC/WTHAMS/00416.

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 19

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 20

Richard Thomas Our ref: ENVPAC/WTHAMS/00416 Peter Brett Associates Letter ref: WA/2017/124069/01-L01 Caversham Bridge House Your ref: 35678 Waterman Place Reading Date: 13 August 2017 Berkshire RG1 8DN

Dear Richard,

Document review for proposed Poyle Quarry Western Extension, Berkyn Manor Farm, Poyle.

Thank you consulting us with your enquiry for the proposed development above. I apologise for the delay in sending our comments to you, which was due to an internal delay in our Groundwater & Contaminated Land team in reviewing the submitted documents and providing their comments.

In providing this response to you, we have reviewed the following documents:

- Proposed Mineral Extraction and Infilling at Berkyn Manor Farm, Poyle, Near Slough – Report on Groundwater Control and Mitigation (prepared by: Peter Brett Associates; dated: January 2017; reference: 35678/3501; revision: 00)

- Berkyn Manor Farm (Poyle) Quarry (Western Extension) – Groundwater Flow Modelling to Assess Quarrying and Restoration Impacts (prepared by: Golder Associates; dated: March 2017; reference: 1656400.500/A.2)

- Poyle Quarry Western Extension, Berkyn Manor Farm, Berkshire – Flood Risk Assessment (prepared by: Peter Brett Associates; dated: April 2017; reference: 35678/4001)

Our position Overall, we have no in-principle objections to the proposed quarry extension and the submitted documents that we have reviewed have by and large provided sufficient information to confirm that we are likely to request conditions on any planning application that is submitted for the quarry extension.

However, as detailed below, there are some areas that require further explanation and/or clarification in any future revisions of the documents that we have seen. We also note that further information will need to be provided for the biodiversity aspects of the proposed quarry extension, further details of which we have provided below.

We note that the proposed site of the quarry and the access road are between two local planning authority areas – Slough Borough Council and Royal Borough of Windsor and Maidenhead. We are not completely clear on whether any additional works are to be

Cont/d.. carried out on the existing access track (largely in Slough’s area), or whether this is entirely an existing track that will remain unchanged and therefore not form part of any planning application. It would be useful for us to know this in advance of any planning submissions.

Finally, we advise you that a landfilling Environmental Permit will be required for the proposed quarry extension and we have provided you with further details below. We would strongly advise you to twin-track your Permit and planning applications for the quarry so that any changes required of either regime can be reflected in the application for the other regime.

Groundwater and Contaminated Land comments We understand that extensive dewatering will be required to enable the proposed sand and gravel extraction and that subsequent to the extraction the resulting void will be backfilled with inert waste materials. The submitted reports provide details of the proposed dewatering, groundwater flow modelling (predicting the effect of the proposed dewatering in the water table in the vicinity of the site), groundwater and surface water quality in the vicinity of the site and a discussion of groundwater control and mitigation measures that will be adopted during and subsequent to the completion of the works at the site.

Several scenarios were considered by the groundwater flow modelling and the results indicate that groundwater conditions in the vicinity of the site will be altered by the dewatering activity. However we agree that the potential risks associated with changing the groundwater conditions can be mitigated via engineered groundwater controls that will be incorporated into the proposed development. We also note that the Groundwater Control and Mitigation Report concludes that the groundwater quality in the local gravel aquifer is slightly impaired however it is noted, based on the result of the groundwater flow modelling, that the historic landfills and other potential sources are outside the predicted zone of influence of the dewatering activity.

Based on the information submitted to date, we have no objection to the proposal and believe that permission for the development could be granted subject to specific planning conditions considering the groundwater conditions in the vicinity of the site. These conditions will be required to ensure that any potential risks to groundwater are managed by the proposed development of the site.

Environmental Permits The sand and gravel extraction and subsequent infilling of voids with inert wastes associated with this development will require a landfilling Environmental Permit under the Environmental Permitting Regulations 2010, unless an exemption applies. Given the proposed dewatering activity and the location of nearby historical sources of groundwater contamination the Environmental Permit will include a requirement for a groundwater quality monitoring programme in the vicinity of the site. You are advised to contact the National Customer Contact Centre on 08708 506 506 for further advice and to discuss the issues likely to be raised. You should be aware that a Permit may not be granted. Additional ‘Environmental Permitting Guidance’ can be accessed via our main website https://www.gov.uk/topic/environmental-management/environmental-permits.

The Environmental Permit must be obtained separately to any planning permission granted, and may not be granted given the sensitivity of the location. We would strongly advise you to enter Permit pre-application discussions with our Land & Water

Cont/d.. 2 (Environmental Management) team. They can be contacted via our National Customer Contact Centre.

Any works within 8 metres of the Colne Brook (main river) and/or within the floodplain may require a Flood Risk Activity Environmental Permit from us. For further details, please refer to the gov.uk pages at https://www.gov.uk/guidance/flood-risk-activities- environmental-permits.

Because of the length of time it can take to determine a Permit application and so that any changes required for the permit can be reflected in any corresponding planning application, we would also advise you to submit your planning and permitting applications at similar times so that the applications can be twin-tracked.

Flood Risk comments The submitted Flood Risk Assessment (FRA) does not provide any details of the proposed lifetime of the mineral extraction and subsequent infilling programme. We assume that given the climate change allowances used in the FRA that the lifetime of the proposed development will not extend beyond 2039. If the expected lifetime is beyond 2039, then the wrong climate change allowances have been used and this will need to be adjusted in any FRA submitted at planning. It would also be useful to clarify in the FRA the expected lifetime of the development for clarity.

The red-line boundary shown in the FRA is somewhat unclear, and it would be preferable to have a higher scale map showing the exact boundary of the proposed quarry extension, as well as the access road. Currently, the red-line boundary for the quarry extension (Figure 2, Appendix A) appears to show that the access track will cross over part of the Eric Mortimer Rayner Memorial Lakes. It is unclear whether the applicant intends to infill this section of the lake before creating the access track, whether the access track will be raised over this section of lake, or whether this is an error on the Site Layout Plan. This must be clarified and further details about any bridge/raised structures and their impact on the floodplain and/or flow routes would also need to be provided.

Similarly, the red-line boundary plan shown on page 3 of the FRA (Figure 2.1: Site Boundary) shows an access track running between the proposed quarry extension and Poyle Road, Poyle, which the plan appears to show going directly over the Colne Brook in places. We assume this to be a result of the low-scale of the map used. We also note that the FRA indicates that this is an existing access track. It would be useful for the FRA to clarify the exact route of the existing track and associated bridges/structures on a higher scale map for clarity – including the distances from the Colne Brook and other watercourses, and confirmation of any new sections of track that will need to be made for access to the proposed quarry extension. As the access route crosses an area of Flood Zone 3b (correlating with the Colne Brook) we would object in principle to any works within this area that would result in the loss of flood plain.

Our guidance says that a 15% climate change allowance figure should be used as the design flood and the 25% allowance should also be assessed. However, we accept that using the 20% allowance is acceptable in this case, as it means the design flood level used is greater than the 1 in 100 year plus 15% event. We do not require the 1 in 100 year plus 25% event to be assessed in this case as we acknowledge that it is unlikely to differ significantly from the 1 in 100 year plus 20% event.

Please note that the defended areas are only defended up to the 1 in 100 year event, which means that in the design flood event used (1 in 100 year plus 20%) the site will not

Cont/d.. 3 have a dry access route.

Biodiversity comments There is limited scope for comment, the fact it begins from arable land presents a low risk in loss of diverse habitats and therefore biodiversity value.

However, it is unclear from the documents provided whether the gravel extraction activity would take works (including vehicular movement) up to the top of bank of the Colne Brook, or any other (non main river) watercourses. Clarification is also required on whether the existing trees and sparse hedgerows on site would remain and be protected or removed, as these are features of wildlife value and migration links. A scheme to protect the riparian habitat and other features of wildlife value (within the footprint of the operation) must be provided at the planning application stage.

Furthermore, according to aerial images the Colne Brook looks to be a permanent water carrier with good bankside vegetation cover for its entirety, therefore protected species, such as European water vole, should be surveyed to ensure that no protected species depend on this waterbody and that its condition should not be negatively impacted by the preparatory and operational works. Such surveys should be conducted prior to the submission of any planning application and the results of any surveys submitted at planning. Such surveys cannot be conditioned at the planning application stage.

An ecological appraisal report which looks into the whether the footprint and stages of development could affect local wildlife, including migration pathways - would be appropriate to ensure that all potential wildlife issues are reviewed. Ecological surveys should be carried out in the optimum timeframe for the target species, and include future mitigation and enhancement options for the site as a whole, so that the proposal presents a net gain for biodiversity value by the end of its operational lifetime.

Should protected species be found to utilise the Colne Brook and its corridor, appropriate avoidance mitigation for each stage of development should be proposed, to comply with wildlife legislation for all stages of the proposal.

In particular, because there is relatively high wildlife value in the nearby waterbodies present (particularly the Colne Brook and Eric Mortimer Rayner Memorial Lakes, including any connected habitats) within this landscape context, hydrological impact studies should demonstrate whether stages of the proposal, for example including the dewatering proposals, could affect such waterbodies. They should identify hydrological connectivity pathways, with appropriate mitigation provided if any assessment indicates that the development, throughout its lifetime, shall at any point affect the natural functioning of those waterbodies, as well as potentially affect migration pathways for flora and fauna.

We recommend that an integral part of the close-down proposal would be to enhance the retained hedgerow, scrub and riparian habitat in order to strengthen wildlife migration connectivity throughout the landscape. Appropriate in-channel enhancements could also be considered for the Colne Brook, which would further the wildlife value by introducing varied morphology. If feasible, it would be positive to convert portions of the land into a Priority Habitat. Furthermore, if farming practices are to resume post-extraction, there are several Countryside Stewardship Schemes which would support and facilitate the conversion and enhancement of hedgerows and riparian buffer zones.

Cont/d.. 4 I hope that these comments will help you as you finalise your planning application for the proposed development. We would be happy to review any updated or new documents to be submitted for planning, subject to an update to our current cost recovery agreement.

If you have any queries about any of the issues raised in this response, please do not hesitate to contact me.

Yours sincerely,

Clark Gordon Sustainable Places Planning Specialist

Direct dial 0203 025 8998 E-mail [email protected] cc Federico Tromboni – Peter Brett Associates Mike Lowe - Summerleaze Ltd.

End 5 Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Appendix B Site Location Plan

Site Location Plan produced by PleydellSmithyman, dated August 2017:

 M16.163.D.005: Location Plan

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 21

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 22

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Appendix C Topographical Survey

Topographical Survey undertaken by SLR:

 Site Survey, Drawing No. 001, dated October 2015

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 23

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 24

NOTES REPRODUCED BY PERMISSION OF ORDNANCE SURVEY ON N BEHALF OF HMSO. CROWN COPYRIGHT AND DATABASE RIGHT OS DATA LICENCE EXPIRATION: 04-09-2016 1. SURVEY CARRIED OUT BY SLR CONSULTING ALL RIGHTS RESERVED. LICENCE NUMBER AL100012293 W E LTD ON 23rd OCTOBER 2015. 2. THIS PLAN IS ORIENTATED TO ORDNANCE SURVEY NATIONAL GRID AND NEWLYN DATUM S DERIVED FROM ORDNANCE SURVEY ACTIVE NETWORK (OSTN02,OSGB36)

3. THIS PLAN HAS NO SCALE FACTOR APPLIED; THE OSGB36 DATUM IS BASED ON THE ORIGIN OF SURVEY CONTROL POINT STA1.

4. THE ACCURACY OF THIS SURVEY IS COMMENSURATE WITH THE DRAWING SCALE SPECIFIED WITHIN THE TITLE BLOCK. ALL CRUCIAL DIMENSIONS SHOULD BE CHECKED ON SITE.

LEGEND

STA1 39.355 SURVEY CONTROL

GATE

FENCE

EDGE OF HEDGE

SURVEYED TOPOGRAPHIC CONTOURS

OVERHEAD WIRES

TREE

DROP KERB

KERB BOTTOM Lake

KERB TOP

AREA OVERGROWN / DENSE VEGETATION

Water level 18.96mAOD Lake Water level 19.03mAOD WATER

Silt Pond SILT POND

SURVEY ABBREVIATIONS

BT Telecommunications Inspection Cover Pipes FH Fire Hydrant G Gully GM Gas Marker LB Litter Bin LP Lamp Post

Lowest Cable level

29.39mAOD MH Manhole MKR Marker Post PO Post RS Road Sign ST Stop Tap SV Sluice Valve TL Traffic Light WM Water Meter

Electricity Pylon

Grass Verge

MH CL21.66

CL21.66

30.63mAOD Lowest Cable level Cable Lowest

MH CL21.59

Water level 18.94mAOD

Electricity Pylon Eric Mortimer Rayner Memorial Lakes Water level 18.55mAOD 0 NPS VSQ 10/15

Revision By Chk'd By Date Comments

7 WORNAL PARK 30.42mAOD

Lowest Cable level Cable Lowest MENMARSH ROAD WORMINGHALL, AYLESBURY BUCKS. HP18 9JX T: 01844 337380 F: 01844 337381 www.slrconsulting.com

Site POYLE, COLNBROOK

Project TOPOGRAPHICAL SURVEY

Drawing Title SITE SURVEY 23rd OCTOBER 2015

Scale Date 1:2000 @ A1 OCTOBER 2015 Drawing Number Revision 001 0 401.00063.00007.09_1015_POYLE_0.dwg Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Appendix D Proposed Development Plans

Drawings produced by PleydellSmithyman, dated August 2017:

 M16.163.D.006: Application Plan

 M16.163.D.007: Current Situation

 M16.163.D.008: Block Phasing

 M16.163.D.009: Proposed Restoration Plan

Drawing provided by Peter Brett Associates, dated September 2017:

 35678/Figure 5 Proposed Mitigation Measures Plan

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 25

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 26

R l

L y P

S o

N E

K C I P D Weir McKay Estate

T Trading n

a r

D N Y A

E W C S BROOK WY

E MILL Y

R W

L K

C O D C

O E

R A N B I

L T L

L E I S N M U

D O C G I E U

S R A

R I D

E 21m

A L H

T O

Depot

R R A Y E M

M D

A R I K W R I

G H T R O A R D E L Y Depot

Estate O E E

Britannia

C L Industrial

in W R

a L

C A

r O

D Y Poyle

E D

L D H

S A

E O

R T

A L F 21m

A K

D C

L N T A

C L T L O O

C B

D S

L A

E O R E L Y O E P S E R Hotel

U O R

n i

a A r L C D P

E n i

a r E D R

n i a r N D I A Farm

Manor

i T

r Sta Ppg

P D

K Y

P N

Y B n L i

Farm a N A r Farm A Poyle D Tanhouse

A Poyle

Lodge r

21m

n i a r r

Conveyor D D

C E

T O

P E K

r R

o B

L S

W T E M

E T

E T O R C T

AL S

A W k

c M K

R r

S k

A T

H c

A P

n i a

a D T

K r

T M

L T

Riverside

T S

O Bungalows

S H T

E H G

ID T

R R

B k

n c

21m i

r a

D r

W S

PW AY D

W U R

Hall

n i r a r

D T

n i

a r

School k o o r

Colnbrook B

City Post

21m n C of C of Primary E l

C W

E h S g ck M ra u T O o L l W

E B

C S

G R

A C I V

T R

E E

i a n r E N D

R Y L T A C S R N

O T

A T

S N H U IG Colnbrook H

n i

a r W D

Memorial Lakes

Eric Mortimer Rayner Mortimer Eric P

E Sl

F D I

D S

D t

a N P L

W L

O C L E L I

W R

O M n E i

V a A r

D AN EL R

n i

T a

C D

O L N O

C AC E B

S E P O P

a Farm

r Manor Berkyn

D Farm Mildridge

Weir

N A L

U O F

R l

L L

P y

N P

E o K

C I D P Weir McKay Estate

T Trading n

a r

D N Y A

E W C S OK WY N MILLBRO MH CL21.15 E LP E MH CL 2 1 . 0 6 ST

S Y PO MH CL21.13 PO

PO I ST RS PO PO

R PO W

MH CL21.01

PO PO LP ST MH CL20.88 G L

HPO K PO MH CL20.82 PO ST

PO D O C C PO PO PO PO PO PO RS

G T O PO MH CL20.79 PO MH CL20.86

G E PO TP

WM R

MH CL20.88 RS G A PO

PO A N B G PO

G I L MH CL20.90 ST PO MH CL21.00 G

MH CL20.89 T L PO L E I PO M RS MH CL20.99 S MH CL21.06

CL20.84 M LP G ST

G U

MH CL20.99 O LP RS

D ST

WM MH CL 2 1 . 0 4 C I G

Gravel PO

MH CL21.06

2 0 U PO G

MH CL20.94 PO ST R

MH CL 2 1 . 1 4 A

MH CL 2 1 . 0 1 D

T R I D E PEG RS

G SV 21m

SV A L WM PO

20 Grass Verge

T MH

CL21.25 O

C T I D

Depot

MH CL21.18 ST R

R MH CL21.23 ST G ST

MH CL21.14

MH CL21.21

0 Y E 2 Grass Verge

0 G G LP M MH CL 2 1 . 2 4

MH CL21.22

D PO

MH CL 2 1 . 1 0 A R I K W R I

G G H MH T CL21.38 R O A R D MH CL20.98 Grass Verge BT CL21.07 E MH CL21.09 MH CL 2 0 . 9 6 G MH CL21.01 MH MH CL21.00 CL21.17 L Y G

Depot

LP Estate 0 MH E O E CL21.05 2 G

PO Britannia MH CL21.10

MH CL 2 1 . 1 0 C L Industrial LP N

G ST

MH CL21.18 R

n W WM

i SV

L H

a C T I GM

C A D 2

r O

G 0 MH CL 2 1 . 6 6

D Y

E D

ST LP

L MH CL 2 1 . 6 6 D H

S A

E O

R T

MH CL21.59 A L F 21m

2 A K

D C

L N T A

C L T L

2 O 0

C B

D S

L A

E O R E L Y O E P S E R Hotel

U O R

n i

a A r

L C D P 0 2

2 0

E n i

a r E D

T C

T I

D n i a r

N PO D S PO

I PO PO

E PO

0 K

A E C

R T 2

R Farm PO

Manor

L PO

TP R T

a PO

r Sta Ppg

P D H C STOCKPILE T I D

K Y

SAND 0 STOCKPILE PO

P N PO

STOCKPI LE

A 2 R

O R

W O

I Y 0 P E

V 2 N

STO CKPILE

O B C Y SAND

20 STOCKPILE L YOR 2 i

N STOCKPILE 0

CO K C

A R

Farm T a

N 0 R

2 r

Y FH

V O

0 E

N 2

N O

O Farm

C C

20 Poyle D

A 2 0 0

2 PO Tanhouse 2 PO

STOCKPILE 0 Car Park PO 0 B 2 PO PO

Lake 0

TP 2

L PO

0 2 2 0 Weighbridge Pipe Office Poyle A STOCKPILE

Lodge r

21m i

2 0

e 2

0 R

T W

2 STOCKPILE

n 0

n 2 i

a r r 0 D

Pipe 2 0 D

E 2

L 0

0 C 0 C 2 E A

0 2

T 0 0

2 2 S

P E

K 2

2 0 0 O

STOCKPILE

O Wash Wheel k

r R

B 2 o

L S

I STOCKPI LE

W T E

M 0

T Pond Silt

E 2

E T O R C T

2 0

L STOCKPI LE

A S

A W k

c M K

R r

S k

T K C

A A

H c

A P

n i a

a D STOCKPILE T

K r

T M

L T

Riverside

T S

O Bungalows

S H

K A C T C R

20 K A C T R

E H 20

G T 0

ID 2

R R

B k

n c

21m i

r a

D r

2 T W S

PW AY D

W U R Lake

Hall

Water level 19.03mAOD level Water

a n

i r a r

0 D

R T

n i

20 a

0 D 2

2 K

C A R T MK R MK R 20 River

20 Pipes

20 0

20 2

P Water level 18.96mAOD level Water

School k o MK R o MK R r Colnbrook B

0 C A

R T City Post

0 e 2

21m n C of C of Primary E

C E

0 G

D I W 2 R

L I

0 2

River

2 0

E Water level 18.94mAOD 0

h 2

S 0

2 g k

2 c 0 M ra u T O o L l W

E B

C 2 S

G R

A 0

A C I

2 0 0 2

0 2

0 0 2

T R 2

E E Water level 18.55mAOD

2 Memorial Lakes n i a r

E N 0 0 D

2 2

R Y 0 Rayner Mortimer Eric L T A C 0 S R 2 N

T 2

2 0 0 N 20 A T

S N H U IG Colnbrook H

n i

a r W D

Memorial Lakes

Eric Mortimer Rayner Mortimer Eric P

E Sl

F D I

D S

D t

a N P L

W 2

O C

E 2 L 0 L I

W R

O 2

0 M n E 20 i V a A r

3 . 0 m 2 A 4 O D

L s w e t o b C a

l v e e e l

D l

Pylon

0 3 6

. Electricity m 3 A

N D

L o w e s

t C a b e l e l v

e LA l Pylon

E Electricity

R 0 2 O e level bl owest Ca L OD

M 29.39mA

n i

T a r C TP D

E 2 TP 0 2

O L N O

C 20

AC E 0

B 2

S E P O P

a Farm

r Manor Berkyn

D Farm Mildridge

Weir

N A L

U O F

R l

L L

P y

N P

E o K

C I D P Weir McKay Estate

T Trading n

a r

D N Y A

E W C S OK WY N MILLBRO MH CL21.15 E LP E MH CL 2 1 . 0 6 ST

S Y PO MH CL21.13 PO

PO I ST RS PO PO

R PO W

MH CL21.01

PO PO LP ST MH CL20.88 G L

HPO K PO MH CL20.82 PO ST

PO D O C C PO PO PO PO PO PO RS

G T O PO MH CL20.79 PO MH CL20.86

G E PO TP

WM R

MH CL20.88 RS G A PO

PO A N B G PO

G I L MH CL20.90 ST PO MH CL21.00 G

MH CL20.89 T L PO L E I PO M RS MH CL20.99 S MH CL21.06

CL20.84 M LP G ST PO G U

MH CL20.99 LP PO O LP RS ST

D PO

WM MH CL 2 1 . 0 4 C G I PO

Gravel PO

MH CL21.06

2 0 U PO G

MH CL20.94 PO ST R

MH CL 2 1 . 1 4 A

MH CL 2 1 . 0 1 D

T R I D E PEG RS

G SV 21m

SV A L WM PO

20 Grass Verge

T MH

CL21.25 O

C T I D

Depot

MH CL21.18 ST R

R MH CL21.23 ST G ST

MH CL21.14

MH CL21.21

0 Y E 2 Grass Verge

0 G G LP M MH CL 2 1 . 2 4

MH CL21.22

D PO

MH CL 2 1 . 1 0 A R I K W R I

G G H MH T CL21.38 R O A R D MH CL20.98 Grass Verge BT CL21.07 E MH CL21.09 MH CL 2 0 . 9 6 G MH CL21.01 MH MH CL21.00 CL21.17 L Y G

Depot

LP Estate 0 E O E MH CL21.05 2 G

PO Britannia MH CL21.10

MH CL 2 1 . 1 0 C L Industrial LP N

G ST

MH R CL21.18

n W WM

i SV

L H

a C T I GM

C A D 2

r O

G 0 MH CL 2 1 . 6 6

D Y

E D

ST LP

L MH CL 2 1 . 6 6 D H

S A

E O

R T

MH CL21.59 A L F 21m

2 A K

D C

L N T A

C L T L

2 O 0

C B

D S

L A

E O R E L Y O E P S E R Hotel

U O R

n i

a A r

L C D P 0 2

2 0

E n i

a r E D

T C

T I

D n i a r

N PO D S PO

I PO PO

E PO

0 K

A E C

R T 2

R Farm PO

Manor

L PO

TP R T

a PO

r Sta Ppg

P D H C STOCKPILE T I D

K Y

STOCKPILE 0 PO

P N PO

STOCKPILE 0

A O 2

Y R

V O N

O Y 0

C E

V 2 N

STO CKPILE O

Y B C n 20 STOCKPILE

L R 2 i EYO

NV 0

CO K

STOCKPILE A

R Farm T R

O a

Y A

N E 0 V R

N 2 r

O O

C Y FH

V O

0 E

N 2

N O

O Farm

C C

20 Poyle D

A 2 0 0

2 PO

Tanhouse 2 PO

0 PO

0 0 2 PO B HO PPER 2 PO

Lake 0

2 2

L PO

0 2 2 0

0 Pipe

2 Poyle A STOCKPILE Lodge

STOCKPILE r

21m i

2 0

e 2

0 R

T W

2 STOCKPILE

n 0

n 2 i

a r r 0 D

Pipe 2 Conveyor 0 D

E 2

L 0

0 C 0 C 2 E A

0 2

T 0 0

2 2 S

P E

K 2

2 0 0 O

STOCKPILE

r R

B 2 o

L S

I STOCKPI LE

W T E

M 0

T Pond Silt

E 2

E T O R C T

2 0

L STOCKPI LE

A S

A W k

c M K

R r

S k

T K C

A A

H c

A P

n i a

a D STOCKPILE T

K r

T M

L T

Riverside

T S

O Bungalows

S H

K A C T C R

20 K A C T R

E H 20

G T 0

ID 2

R R

B k

n c

21m i

r a

D r

2 T W S

PW AY D

W U R Lake

Hall

Water level 19.03mAOD level Water

a n

i r a r

0 D

R T

n i

20 a

0 D 2

2 K

C A R T MK R MK R 20 River

20 Pipes

20 0

20 2

P Water level 18.96mAOD level Water

School k o MK R o MK R r Colnbrook B

0 C A

R T City Post

0 e 2

21m n C of C of Primary E

C E

0 G

D I W 2 R

L I

0 2

River

2 0

E Water level 18.94mAOD 0

h 2

S 0

2 g k

2 c 0 M ra u T O o L l W

E B

C 2 S

G R

A 0

A C I

2 0 0 2

0 2

0 0 2

T R 2

E E Water level 18.55mAOD

2 Memorial Lakes n i a r

E N 0 0 D

2 2

R Y 0 Rayner Mortimer Eric L T A C 0 S R 2 N

T 2

2 0 0 N 20 A T

S N H U IG Colnbrook H

n i

a r W D

Memorial Lakes

Eric Mortimer Rayner Mortimer Eric P

E Sl

F D I

D S

D t

a N P L

W 2

O C

E 2 L 0 L I

W R

O 2

0 M n E 20 i V a A r

3 . 0 m 2 A 4 O D

L s w e t o b C a

l v e e e l

D l

Pylon

0 3 6

. Electricity m 3 A

N D

L o w e s

t C a b e l e l v

e LA l Pylon

E Electricity

R 0 2 O e level bl owest Ca L OD

M 29.39mA

n i

T a r C TP D

E 2 TP 0 2

O L N O

C 20

AC E 0

B 2

S E P O P

a Farm

r Manor Berkyn

D Farm Mildridge

Weir

N A L

U O F

R l

L L

P y

N P

E o K

C I D P Weir McKay Estate

T Trading n

a r

D N Y A

E W C S OK WY N MILLBRO MH CL21.15 E LP E MH CL 2 1 . 0 6 ST

S Y PO MH CL21.13 PO

PO I ST RS PO PO

R PO W

MH CL21.01

PO PO LP ST MH CL20.88 G L

HPO K PO MH CL20.82 PO ST

PO D O C C PO PO PO PO PO PO RS

G T O PO MH CL20.79 PO MH CL20.86

G E PO TP

WM R

MH CL20.88 RS G A PO

PO A N B G PO

G I L MH CL20.90 ST PO MH CL21.00 G

MH CL20.89 T L PO L E I PO M RS MH CL20.99 S MH CL21.06

CL20.84 M LP G ST

G U

MH CL20.99 O LP RS

D ST

WM MH CL 2 1 . 0 4 C I G

Gravel PO

MH CL21.06

2 2 0 0 U PO G

MH CL20.94 PO ST R

MH CL 2 1 . 1 4 A

MH CL 2 1 . 0 1 D

H H

C C

T T

I R I D D E PEG RS

G SV 21m

SV A L WM PO

20 Grass Verge

T MH

CL21.25 O

H H

C C T T

I I D D

Depot

MH CL21.18 ST R

R MH CL21.23 ST G ST

MH CL21.14 MH CL21.21

0 0 Y

2 E 2 Grass Verge

0 G G LP M MH CL 2 1 . 2 4

MH CL21.22

D PO

MH CL 2 1 . 1 0 A R I K W R I

G G H MH T CL21.38 R O A R D MH CL20.98 Grass Verge BT CL21.07 E MH CL21.09 MH CL 2 0 . 9 6 G MH CL21.01 MH MH CL21.00 CL21.17 L Y G

Depot

LP Estate 0 MH E O E CL21.05 2 G

PO Britannia MH CL21.10

MH CL 2 1 . 1 0 C L Industrial LP N

G ST

MH CL21.18 R

n W WM

i SV

L H

a C T I GM

C A D

2 2

r O

0 0 MH CL 2 1 . 6 6

D Y

E D

ST LP

L MH CL 2 1 . 6 6 D H

S A

2 2

0 0

E O

R T

MH CL21.59 A L F 21m

2 A K

D C

L N T A

C L T L

O 2

2 O 0 0

C B

D S

L A

E O R E L Y O E P S E R Hotel

U O R

n i

a A r

L C D P

2 0 2

2 0 0

E n i

a r E D

2 2

0 0

T C

T I

D n i a r

N PO D S PO

I PO PO

E PO

0 K K

E C

A C

A A

R R

T T 2

R Farm PO

Manor

L PO

2 2

0 0

K K

C C

A A

R TP R

T T

a PO

r Sta Ppg

P D H C STOCKPILE T I D

K Y

2 2

0 SAND 0 STOCKPILE PO

P N PO

STOCKPI LE

0 0

K K

A 2 2 R R

O R R

W O O

E E

P P

I Y

Y 0 P

P E E V

V 2

N N

STO CKPILE

O O

B C C Y SAND

20 STOCKPILE L YOR 2 i

N STOCKPILE 0

CO K C C

A A

R R T

Farm T a

A 0

N 0

R R 2

2 r O O

Y FH

E E

R R

V V O O

Y Y

E 0 E

N N 2

V V

N N

O O

O Farm

C C C C

20 Poyle D

A 2

0 0 0

2 PO 2 Tanhouse 2 PO

STOCKPILE 0 0 Car Park PO 0 B 2 PO PO

Lake

0 0

2 2

L PO

0 2

0 2 0 Weighbridge Pipe Office Poyle A STOCKPILE

Lodge r

21m i

0 0

2 2 0 2

e 2

K K

C C

A A

0 R

T T W

2 STOCKPILE

n 0

2 i

r 0 D

Pipe 2 0 0 D

E 2

L 0

2 2

0 C 0 0 C 2 2 E A

0 0 2 2

T 0 0

2 2 S

P E

K 2

2 0

0 0 O

STOCKPILE

O Wash Wheel k

r R

B 2 o

L S

I STOCKPI LE

W T E

M 0 0

T Pond Silt 2

E 2

E T O R C T

0 0

2 2

2 2 0 0

L STOCKPI LE

A S

A W k

c M K

R r

S k K

T K

C C

A A

R R

T T

H c

A P

n i a

a D STOCKPILE T

K r

T M

L T

Riverside

T S

O Bungalows

S H

K K A A C C T T R C R

K 20 K A A C C T T R R

E H 20

G T 0

ID 2

R R

B k

n c

21m i

r a

D r

2 T W S

PW AY D

W U R Lake

Hall

Water level 19.03mAOD level Water

a n

i r a r

0 0 D

K K

C C

2 2

A A

R R

T T

n i

20 a

0 0 2 D 2

2 K

C A R T MK R 20 MK R River

20 Pipes

20 0

20 2

P Water level 18.96mAOD level Water

School k o MK R o MK R r Colnbrook B

0 C A

R T City Post

0 e 2

21m n C of C of Primary E

C E

0 G

D I W 2 R

L I

0 2

River

2 0

E Water level 18.94mAOD 0

h 2

S 0

2 g k

2 c 0 M ra u T O o L l W

E B

C 2 S

G R

A 0

A C I

2 0 0 2

0 2

0 0 2

T R 2

E E Water level 18.55mAOD

2 Memorial Lakes n i a r

E N 0 0 D

2 2

R Y 0 Rayner Mortimer Eric L T A C 0 S R 2 N

T 2

2 0 0 N 20 A T

S N H U IG Colnbrook H

n i

a r W D

Memorial Lakes

Eric Mortimer Rayner Mortimer Eric P

E Sl

F D I

D S

K 0

O . O 0

2 R

B 21.5

D t

21.0 a + N P L

C 20.5

W L O C

20.0 L E L I

W R O

19.5 M n E i

V a A r

19.0

3 . 0 m 2 A 4 O D

L s w e t o b C a

l v e e e l

D l

Pylon

0 3 6

. Electricity m 3 A

N D

L o w e s

t C a b e l e l v

e LA l Pylon

E Electricity

R 0 2 O e level bl owest Ca L OD

M 29.39mA

n i

T a r C D

E 2 TP 0 2

O L N O

C 20

AC E 0

B 2

S E P O P

a Farm

r Manor Berkyn

D Farm Mildridge

Weir

N A L

U O F COLNBROOK VILLAGE

The Queen Mother Reservoir

POYLE VILLAGE

Colne Brook

HORTON BROOK SITE

Memorial Lakes

Horton Brook site mitigation measures (groundwater Legend interceptor drain). Approximate Site Boundary

Proposed Groundwater Control HORTON VILLAGE System (Recharge trenches and groundwater interceptor drain)

Recorded Abstraction Well

Horton Brook site Mitigation Wraysbury Measures (Groundwater This drawing has been produced in colour. Reproduction in interceptor drain) black and white may result in misinterpretation of the data Reservoir and features being presented.

Client Date 04.09.2017 A3 Scale 1:7500 Drawn by CCu Checked by FT POYLE QUARRY WESTERN EXTENSION, BERKYN MANOR FARM, BERKSHIRE Revision 0 Google Earth Offices throughout the UK and Image Date: June 2015 continental Europe. PROPOSED MITIGATION MEASURES PLAN FIGURE 5 www.peterbrett.com

Appendix E EA Product 4 Data

Environment Agency Product 4 Data (EA ref. HNL/19478/MS) information dated August 2016:

 Flood Zone Map

 Defence information

 Model Information

 Modelled Flood Extents

 Historic flood map

 Historic flood information

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 27

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 28

Flood Map for Planning centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

e t ln i

o D C

C o e o ln l C o n C e ch C Dit o ty un un ty e o D ln C i Environment Agency o tc C h 2 Bishops Square Business Park St Albans Road West Hatfield Hertfordshire • AL10 9EX

Co tte sb roo k D itch 0 130 260 520

Metres Legend Main Rivers Flood Map for Planning Flood Storage Area Colne Areas Benefiting from Flood Defences

l n

e Flood Zone 3

r o

k Flood Zone 2

Flood Map for Planning (assuming no defences)

Flood Zone 3 shows the area that could be affected by flooding: - from the sea with a 1 in 200 or greater es ain St chance of happening each year itch y D - or from a river with a 1 in 100 or greater unt Co k chance of happening each year. o o r B

e ln Flood Zone 2 shows the extent of an extreme o k C o flood from rivers or the sea with up to a 1 in o r C B ol ne 1000 chance of occurring each year. e Br n o l ok o C Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Detailed FRA centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

n l lne o Co

e n l o

Environment Agency 2 Bishops Square Business Park St Albans Road West Hatfield h c t i Hertfordshire D • k o AL10 9EX o r b s e t t o C 0 80 160 320

Metres Legend

o r Main Rivers

C Defended Flood Outlines

1 in 2 (50%) Defended 1 in 5 (20%) Defended 1 in 10 (10%) Defended 1 in 20 (5%) Defended

Colne

The data in this map has been extracted from the Lower Colne Modelling and Mapping Study (Mott MacDonald 2012). This model has been designed for catchment wide flood risk mapping. It should be noted that it was not created to produce flood levels for specific development sites within the catchment. Modelled outlines take into account catchment wide defences. Flood risk data requests including an allowance for climate change will be based on the 1 in 100 flood plus 20% allowance for climate change, unless otherwise stated. You should refer to ‘Flood risk assessments: climate change allowances’ to check if this allowance is still appropriate for the type of development you are proposing and its location. You may need to undertake further assessment of future flood risk using different allowances to ensure your assessment of future flood risk is based on best available evidence. https://www.gov.uk/guidance/flood-risk-assessments- climate-change-allowances

Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Detailed FRA centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

n l lne o Co

e n l o

Environment Agency 2 Bishops Square Business Park St Albans Road West Hatfield h c t i Hertfordshire D • k o AL10 9EX o r b s e t t o C 0 80 160 320

Metres Legend

o r Main Rivers

C Defended Flood Outlines 1 in 50 (2%) Defended 1 in 100 (1%) Defended 1 in 100+20% (*CC) Defended 1 in 1000 (0.1%) Defended

Colne

lne HB.056M Co REL.B HB.052 HB.053 G100U HB.049M HB.051 G100D HB.048M HB.050 G099 G098 HB.047M Environment Agency 2 Bishops Square Business Park St Albans Road West G097 CTD.008 Hatfield Hertfordshire • G096U AL10 9EX G096D CTD.007 CTD.004 CTD.002 CTD.006 CTD.001 CTD.003u 0 80 160 320 Metres

G095 Legend

o r Main Rivers

POYHDO1 C 1D Node Results G094 Node Results

POYHD02 G093 G092U G092D POYHD03 P004 CBR017 Colne P005 P001 P002 CBR016 P003 The data in this map has been extracted from the Lower CBR015 Colne Modelling and Mapping Study (Mott MacDonald 2012). This model has been designed for catchment wide flood risk mapping. It should be noted that it was not created to produce flood levels for specific development sites POYHD04 within the catchment. Modelled outlines take into CBR014 account catchment wide defences. Flood risk data requests including an allowance for climate change will be based on the 1 in 100 flood plus 20% allowance for climate change, unless POYHD05 otherwise stated. You should refer to ‘Flood risk CBR013 assessments: climate change allowances’ to check if this allowance is still appropriate for the type of development POYHDWS07D POYHDWS07 CBR012 you are proposing and its location. You may need to undertake further assessment of future flood risk using different allowances to ensure your assessment of future Moat004D Moat005 CBR011 flood risk is based on best available evidence. Moat004 Moat000 Moat001 Moat006 https://www.gov.uk/guidance/flood-risk-assessments- Moat003 climate-change-allowances Moat010 Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Environment Agency ref: HNL/19478/MS

The data in this map has been extractedfrom the Lower Colne Modelling and Mapping Study (Mott MacDonald 2012).

Flood risk data requests including an allowance for climate change will be based on the 1 in 100 flood plus 20% allowance for climate change, unless otherwise stated. You should refer to ‘Flood risk assessments: climate change allowances’ to check if this allowance is still appropriate for the type of development you are proposing and its location. You may need to undertake further assessment of future flood risk using different allowances to ensure your assessment of future flood risk is based on best available evidence. https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances All flood levels are given in metres Above Ordnance Datum (mAOD) All flows are given in cubic metres per second (cumecs)

MODELLED FLOOD LEVEL Return Period Node Label Easting Northing 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr 100 yr + 20% 1000 yr CB073 502810 177087 19.74 19.84 19.90 19.98 20.22 20.34 20.49 20.54 CB073J 502805 177066 19.74 19.84 19.90 19.98 20.22 20.34 20.49 20.54 CBR011 502343 176063 19.15 19.20 19.20 19.27 19.43 19.51 19.55 19.57 CBR012 502430 176111 19.20 19.25 19.26 19.33 19.51 19.59 19.63 19.66 CBR013 502525 176154 19.25 19.31 19.32 19.40 19.58 19.67 19.72 19.74 CBR014 502524 176246 19.30 19.36 19.37 19.45 19.64 19.73 19.80 19.83 CBR015 502507 176334 19.35 19.41 19.42 19.50 19.70 19.80 19.87 19.91 CBR016 502506 176368 19.38 19.44 19.45 19.53 19.73 19.82 19.90 19.94 CBR017 502520 176402 19.38 19.44 19.45 19.53 19.73 19.82 19.90 19.94 CTD.001 502613 176816 19.40 19.47 19.50 19.58 19.80 19.90 20.00 20.05 CTD.002 502705 176792 19.42 19.48 19.51 19.59 19.80 19.91 20.01 20.07 CTD.003d 502727 176789 19.52 19.55 19.56 19.62 19.80 19.91 20.02 20.08 CTD.003u 502735 176793 19.58 19.60 19.61 19.66 19.84 19.95 20.12 20.16 CTD.004 502778 176801 19.75 19.75 19.75 19.75 19.87 19.96 20.13 20.18 CTD.006 502835 176784 19.80 19.80 19.80 19.80 19.89 19.97 20.15 20.19 CTD.007 502851 176819 19.81 19.81 19.81 19.82 19.89 19.97 20.16 20.21 CTD.008 502877 176876 19.84 19.84 19.84 19.84 19.91 19.98 20.21 20.27 G092D 502521 176449 19.38 19.44 19.45 19.53 19.73 19.83 19.90 19.95 G092U 502521 176458 19.38 19.44 19.45 19.53 19.73 19.83 19.90 19.95 G093 502535 176489 19.38 19.44 19.45 19.54 19.74 19.84 19.91 19.96 G094 502573 176577 19.38 19.45 19.46 19.54 19.75 19.85 19.93 19.98 G095 502577 176666 19.39 19.45 19.47 19.55 19.76 19.87 19.95 20.00 G096D 502596 176813 19.40 19.47 19.50 19.58 19.80 19.90 20.00 20.04 G096U 502601 176823 19.40 19.47 19.50 19.58 19.80 19.90 20.00 20.04 G097 502626 176872 19.41 19.48 19.52 19.61 19.83 19.94 20.04 20.09 G098 502647 176969 19.44 19.52 19.57 19.66 19.89 20.00 20.12 20.16 G099 502732 176994 19.49 19.58 19.64 19.73 19.97 20.09 20.23 20.27 G100D 502779 177025 19.64 19.73 19.79 19.87 20.10 20.22 20.35 20.40 G100U 502785 177044 19.64 19.73 19.79 19.87 20.10 20.22 20.35 20.40 HB.047M 501607 176954 18.83 18.91 18.96 18.99 19.02 19.02 19.01 19.07 HB.048M 501705 176999 18.86 18.93 18.98 19.01 19.03 19.04 19.03 19.08 HB.049M 501749 177019 18.89 18.95 19.00 19.03 19.05 19.06 19.05 19.10 HB.050 501806 177045 18.91 18.96 19.01 19.04 19.06 19.06 19.05 19.11 HB.051 501823 177052 19.06 19.12 19.18 19.21 19.23 19.24 19.23 19.32 HB.052 501830 177055 19.06 19.12 19.18 19.21 19.23 19.24 19.23 19.32 HB.053 501840 177060 19.07 19.13 19.18 19.21 19.23 19.24 19.23 19.32 HB.054M 501874 177075 19.08 19.14 19.19 19.22 19.24 19.25 19.24 19.32 HB.055BD 501886 177081 19.09 19.15 19.20 19.23 19.25 19.25 19.24 19.33 HB.055BU 501899 177087 19.12 19.18 19.23 19.26 19.28 19.29 19.28 19.36 Moat000 502241 176056 18.99 18.99 18.99 19.00 19.04 19.05 19.11 19.15 Moat001 502242 176056 18.99 18.99 18.99 18.99 19.04 19.05 19.11 19.15 Moat002 502146 176061 18.98 18.99 18.99 18.99 19.04 19.05 19.10 19.15 Moat003 502139 176063 18.77 18.78 18.79 18.79 18.80 18.85 18.93 18.98 Moat004 502080 176072 18.76 18.77 18.78 18.78 18.80 18.84 18.93 18.98 Moat004D 502047 176074 18.76 18.77 18.78 18.78 18.80 18.84 18.93 18.98 Moat005 502028 176078 18.76 18.77 18.77 18.78 18.79 18.84 18.92 18.97 Moat006 501997 176041 18.75 18.77 18.77 18.77 18.79 18.84 18.92 18.97 Moat008 501909 176010 18.23 18.23 18.24 18.24 18.25 18.27 18.45 18.56 Moat009 501900 176001 18.22 18.23 18.23 18.23 18.24 18.26 18.45 18.56 Moat010 501837 176009 18.22 18.22 18.22 18.22 18.23 18.25 18.44 18.55 P001 502531 176383 19.38 19.44 19.45 19.53 19.73 19.82 19.90 19.94 P002 502579 176378 19.39 19.45 19.46 19.54 19.74 19.84 19.91 19.96 P003 502675 176374 19.42 19.48 19.49 19.56 19.75 19.86 19.93 19.98 P004 502757 176407 19.44 19.50 19.51 19.57 19.77 19.87 19.94 20.00 P005 502873 176405 19.49 19.55 19.55 19.61 19.80 19.90 19.97 20.04 POYHD02 502304 176508 18.92 18.95 18.96 18.96 18.97 19.00 19.05 19.08 POYHD03 502282 176418 18.91 18.94 18.95 18.95 18.97 19.00 19.04 19.07 POYHD04 502215 176257 18.90 18.93 18.94 18.95 18.96 18.99 19.04 19.07 POYHD05 502162 176163 18.90 18.93 18.94 18.95 18.96 18.99 19.04 19.07 POYHDO1 502337 176592 18.93 18.96 18.97 18.97 18.98 19.01 19.05 19.08 POYHDWS07 502095 176126 18.89 18.92 18.93 18.93 18.95 18.98 19.03 19.07 POYHDWS07D 502094 176126 18.77 18.78 18.79 18.79 18.81 18.85 18.93 18.98 POYHDWS08 502084 176079 18.76 18.77 18.78 18.78 18.80 18.84 18.93 18.98 REL.A1 502848 177081 19.83 19.93 20.00 20.08 20.30 20.44 20.59 20.64 REL.A2 502832 177078 19.80 19.89 19.96 20.04 20.27 20.39 20.54 20.59 REL.AD 502868 177085 19.86 19.95 20.02 20.10 20.33 20.46 20.60 20.65 REL.AJ 502817 177073 19.74 19.84 19.90 19.98 20.22 20.34 20.49 20.54 REL.B 502908 177067 19.87 19.96 20.04 20.12 20.34 20.47 20.61 20.66

MODELLED FLOWS Return Period Node Label Easting Northing 2 yr 5 yr 10 yr 20 yr 50 yr 100 yr 100 yr + 20% 1000 yr CB073 502810 177087 0.27 0.34 0.39 0.45 0.69 0.82 1.06 1.17 CB073J 502805 177066 2.50 3.11 3.64 4.20 6.04 7.12 8.59 9.14 CBR011 502343 176063 7.20 7.96 8.07 9.10 11.89 13.31 14.10 14.58 CBR012 502430 176111 7.20 7.96 8.07 9.10 11.89 13.31 14.10 14.58 CBR013 502525 176154 7.20 7.96 8.07 9.10 11.89 13.68 15.44 16.51 CBR014 502524 176246 7.20 7.96 8.07 9.10 11.89 13.68 15.44 16.51 CBR015 502507 176334 7.20 7.96 8.07 9.10 11.89 13.78 16.36 18.43 CBR016 502506 176368 7.20 7.96 8.07 9.10 11.89 13.79 16.42 18.61 CBR017 502520 176402 2.67 3.25 3.78 4.34 6.19 7.26 8.78 9.46 CTD.001 502613 176816 0.14 0.14 0.14 0.14 0.14 0.15 0.56 0.93 CTD.002 502705 176792 0.14 0.14 0.14 0.14 0.14 0.14 0.54 0.76 CTD.003d 502727 176789 0.14 0.14 0.14 0.14 0.14 0.14 0.32 0.27 CTD.003u 502735 176793 0.14 0.14 0.14 0.14 0.14 0.14 0.32 0.27 CTD.004 502778 176801 0.14 0.14 0.14 0.14 0.14 0.14 0.43 0.52 CTD.006 502835 176784 0.14 0.14 0.14 0.14 0.14 0.14 0.43 0.52 CTD.007 502851 176819 0.14 0.14 0.14 0.14 0.14 0.14 0.53 0.76 CTD.008 502877 176876 0.14 0.14 0.14 0.14 0.14 0.14 0.53 0.76 G092D 502521 176449 2.67 3.25 3.78 4.34 6.19 7.26 8.78 9.46 G092U 502521 176458 2.67 3.25 3.78 4.34 6.19 7.26 8.78 9.46 G093 502535 176489 2.66 3.25 3.78 4.34 6.18 7.26 8.78 9.46 G094 502573 176577 2.66 3.25 3.78 4.34 6.18 7.26 8.78 9.46 G095 502577 176666 2.66 3.25 3.78 4.34 6.18 7.26 8.78 9.45 G096D 502596 176813 2.65 3.25 3.78 4.34 6.18 7.26 8.78 9.46 G096U 502601 176823 2.51 3.11 3.64 4.20 6.04 7.12 8.39 8.53 G097 502626 176872 2.51 3.11 3.64 4.20 6.04 7.12 8.39 8.53 G098 502647 176969 2.51 3.11 3.64 4.20 6.04 7.12 8.59 9.12 G099 502732 176994 2.51 3.11 3.64 4.20 6.04 7.12 8.59 9.14 G100D 502779 177025 2.50 3.11 3.64 4.20 6.04 7.12 8.59 9.14 G100U 502785 177044 2.50 3.11 3.64 4.20 6.04 7.12 8.59 9.14 HB.047M 501607 176954 1.11 1.13 1.16 1.17 1.19 1.19 1.18 1.22 HB.048M 501705 176999 1.12 1.14 1.16 1.18 1.19 1.19 1.19 1.22 HB.049M 501749 177019 1.12 1.14 1.16 1.18 1.19 1.20 1.19 1.23 HB.050 501806 177045 1.12 1.15 1.16 1.18 1.19 1.20 1.19 1.23 HB.051 501823 177052 1.12 1.15 1.16 1.18 1.19 1.20 1.19 1.23 HB.052 501830 177055 1.12 1.15 1.16 1.18 1.19 1.20 1.19 1.23 HB.053 501840 177060 1.12 1.15 1.17 1.18 1.20 1.20 1.19 1.23 HB.054M 501874 177075 1.12 1.15 1.17 1.19 1.20 1.20 1.20 1.23 HB.055BD 501886 177081 1.12 1.15 1.17 1.19 1.20 1.21 1.20 1.23 HB.055BU 501899 177087 1.12 1.15 1.17 1.19 1.20 1.21 1.20 1.23 Moat000 502241 176056 0.42 0.46 0.48 0.53 0.62 0.65 0.66 0.65 Moat001 502242 176056 0.41 0.44 0.46 0.51 0.59 0.68 0.98 1.22 Moat002 502146 176061 0.21 0.22 0.22 0.22 0.23 0.23 0.24 0.25 Moat003 502139 176063 0.21 0.22 0.22 0.22 0.23 0.23 0.24 0.25 Moat004 502080 176072 0.21 0.22 0.22 0.22 0.23 0.30 0.38 0.39 Moat004D 502047 176074 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.59 Moat005 502028 176078 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.56 Moat006 501997 176041 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.58 Moat008 501909 176010 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.58 Moat009 501900 176001 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.59 Moat010 501837 176009 0.41 0.42 0.43 0.43 0.45 0.50 0.56 0.58 P001 502531 176383 4.80 5.15 5.09 4.95 5.71 6.53 7.64 9.27 P002 502579 176378 4.81 5.16 5.10 4.96 5.71 6.50 7.45 8.78 P003 502675 176374 4.82 5.17 5.11 4.96 5.71 6.17 6.30 6.98 P004 502757 176407 4.82 5.18 5.12 4.97 5.72 6.42 7.14 8.20 P005 502873 176405 4.83 5.19 5.13 4.98 5.72 6.53 7.67 9.30 POYHD02 502304 176508 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 POYHD03 502282 176418 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 POYHD04 502215 176257 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 POYHD05 502162 176163 0.11 0.11 0.11 0.11 0.10 0.10 0.12 0.30 POYHDO1 502337 176592 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 POYHDWS07 502095 176126 0.19 0.21 0.21 0.21 0.21 0.21 0.21 0.21 POYHDWS07D 502094 176126 0.19 0.21 0.21 0.21 0.21 0.21 0.21 0.21 POYHDWS08 502084 176079 0.19 0.21 0.21 0.21 0.21 0.21 0.21 0.26 REL.A1 502848 177081 2.23 2.78 3.25 3.75 5.35 6.30 7.52 7.57 REL.A2 502832 177078 2.23 2.78 3.25 3.75 5.35 6.30 7.51 7.55 REL.AD 502868 177085 2.23 2.78 3.25 3.75 5.35 6.31 7.61 7.68 REL.AJ 502817 177073 2.23 2.78 3.25 3.75 5.35 6.30 7.54 7.97 REL.B 502908 177067 2.06 2.57 3.03 3.51 5.12 6.07 7.36 7.44 Detailed FRA centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

n l olne 88 79 o C

C 96 97 87 e n 105 95 l 112 o 116 C 123 126 135 122 137 139 140 152 Environment Agency 169 170 173 176 2 Bishops Square Business Park 196 197 St Albans Road West 200 Hatfield h c t 220 221 i Hertfordshire D 226 • k o AL10 9EX o r 245 246 b 249 252 s e t t o 267 268 C 269 270 271 0 80 160 320 284 285 286 287 Metres 283 301 302 304 305 316 317 319 Legend 322 335 337 338 341 Main Rivers 349 366 367 371 372 373 376 2D Node Results: Heights 387 411 414 415 419 420 421 423 435 1 in 100+20% (*CC) Defended 453 455 457 459 460 461 471 484 485 488 491 492 508 511 529 532 534 535 537

554 o

o 571 574 576 577 r

595 n Colne

612 615 617 618 o

C 636 651 655 658 661 664 The data in this map has been extracted from the Lower Colne Modelling and Mapping Study (Mott MacDonald 688 701 702 2012). 705 708 711 714 This model has been designed for catchment wide flood 754 756 757 risk mapping. It should be noted that it was not created 759 761 764 767 770 773 to produce flood levels for specific development sites 824 827 828 within the catchment. Modelled outlines take into 830 832 835 837 838 842 account catchment wide defences. 894 895 896 Flood risk data requests including an allowance for 899 902 905 907 910 913 916 919 climate change will be based on the 1 in 100 flood 978 980 981 plus 20% allowance for climate change, unless 985 987 988 993 996 998 999 otherwise stated. You should refer to ‘Flood risk 979 assessments: climate change allowances’ to check if this 1047 984 997 1070 977 991 994 995 allowance is still appropriate for the type of development 1142 1145 1149 1153 1166 1108 you are proposing and its location. You may need to 1157 1161 1165 undertake further assessment of future flood risk using different allowances to ensure your assessment of future 1230 1234 1238 1242 1246 1250 1254 1256 1257 flood risk is based on best available evidence. 1255 https://www.gov.uk/guidance/flood-risk-assessments- 1317 1322 1326 1330 1334 1336 1337 climate-change-allowances 1386 1390 1392 1393 1316 1394 1398 1402 1406 1408 1409 Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Historic Flood Map centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

e t ln i

o D C

C o e o ln l C o n C e ch C Dit o ty un un ty e o D ln C i Environment Agency o tc C h 2 Bishops Square Business Park St Albans Road West Hatfield Hertfordshire • AL10 9EX

Co tte sb roo k D itch 0 130 260 520

Metres Legend Main Rivers Flood Event Outlines 2014 Colne 2003

l n 2001 e

r o o 2000 k 1947

The historic flood event outlines are based on a combination of anecdotal evidence, Environment Agency staff observations and survey. es ain Our historic flood event outlines do not St itch y D provide a definitive record of flooding. unt Co It is possible that there will be an absence of k o o r datain places where we have not been able B

e to record the extent of flooding. ln o k C o It is also possible for errors occur in the

o r C B ol digitisation of historic records of flooding. ne e Br n o l ok o C Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Structures and Defences centred on Poyle Quarry - 05/08/2016 - HNL/19478/MS

n l lne o Co

e n l o

Environment Agency 2 Bishops Square Business Park St Albans Road West Hatfield h c t i Hertfordshire D • k o AL10 9EX o r b s e t t o C 0 85 170 340

Metres Legend

o r Main Rivers

o NAFRA_DEFENCE

C ASSET_ID 55398 55777 73096 73316 Colne

The following information on defences has been extracted from the Asset Information Management System (AIMS) Produced by: Partnerships & Strategic Overview, This map is based upon Ordnance Survey Material with the permission of Ordnance Survey on behalf of the controller of Her Majesty's Stationery Office Crown Copyright. Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Environment Agency 100024198, 2015 Hertfordshire & North London Environment Agency ref: HNL/19478/MS

The following information on defences has been extracted from the Asset Information Management System (AIMS)

Defences Condition of Design Standard of Downstream Upstream Crest Asset ID Asset Type Asset Protection Asset Comment Asset Description Defences (1=Good, protection (years) Crest Level Level 5 = Poor) Natural Vegetated 73096 high_ground fluvial Natural Bank 100 19.53 21.3 2 Channel Natural Vegetated 73316 high_ground fluvial Natural Bank 100 19.78 22.2 2 Channel Natural vegetated 55398 high_ground fluvial Natural Bank 80 21 22.13 channel Natural vegetated 55777 high_ground fluvial Natural Bank 80 20.12 22.32 channel Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

Appendix F RBWM SFRA Figures

Windsor and Maidenhead SFRA Figures:

 Figure 11 Flood Extents, dated May 2017

 Figure 11 Flood Zones, dated May 2017

 Figure E Areas Susceptible to Groundwater Flooding, dated May 2017

 Figure 20 Flood Zone Map, dated September 2013

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 29

Poyle Quarry Western Extension, Berkyn Manor Farm. Flood Risk Assessment

J:\35678 - Poyle Quarry\Hydro\wp\FRA_Quarry Site\35678_Poyle Quarry Site_FRA_October Final.docx 30

HO 0008

DA 0016

HO 0011

HO 0010

HO 0009

HO 0005 HO 0006

HO 0004

HO 0001

WR 0024

Legend WR 0023

RBWM Boundary

Main Rivers

Flood Defences WR 0030 Potential Site Allocations Windsor and Maidenhead Zone 2 Medium Probability SFRA Zone 3a High Probability Flood Zone Map Zone 3b Functional Floodplain WR 0027 Figure 20 Zone 3b Developed

Zone 3b Functional Floodplain unknown ± Kilometers Areas Benefitting from Defences 0 0.2 0.4

Non Fluvial Flooding September 2013 Flooding from Sewers This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller WR 0028 of Her Majesty's Stationary Office. Crown Copyright. Flooding from Other Sources Unauthorised reproduction infringes Crown Copyright and may lead to prosecution or civil proceedings. Flooding from Unknown Sources Environment Agency Licence No 100026380 2006.