Flood Risk Scoping Assessment

Appendix G

FLOOD RISK SCOPING ASSESSMENT

New Thames Crossing east of Reading Flood Risk Scoping Assessment

On behalf of: Wokingham Borough Council

Project Ref: 37006/4001 | Rev: - | Date: October 2016

Office Address: Caversham Bridge House, Waterman Place, Reading, Berkshire RG1 8DN T: +44 (0)118 950 0761 F: +44 (0)118 959 7498 E: [email protected] Flood Risk Scoping Assessment New Thames Crossing east of Reading

Document Control Sheet

Project Name: New Thames Crossing east of Reading Project Ref: 37006/4001 Report Title: Flood Risk Scoping Assessment Doc Ref: - Date: October 2016

Name Position Signature Date

Prepared by: Jodie Hall Assistant Modeller J. Hall

Reviewed by: Richard Fisher Associate R.Fisher

Approved by: Chris Downs Director of Water D.Walker

For and on behalf of Peter Brett Associates LLP

Revision Date Description Prepared Reviewed Approved

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.

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Contents

1 Introduction ...... 2 Scope of Report ...... 2 Sources of Information ...... 2 Policy Context ...... 3 2 Proposed Route Setting ...... 4 Proposed Route Description ...... 4 Proposed Development ...... 5 Topography ...... 5 Watercourses and Flood Defences ...... 5 Geology ...... 6 3 Overview of Flood Risk ...... 7 EA Flood Maps ...... 7 Wokingham Borough Council Preliminary Flood Risk Assessment ...... 9 Oxfordshire County Council Preliminary Flood Risk Assessment ...... 10 Wokingham Borough Council Strategic Flood Risk Assessment ...... 10 South Oxfordshire District Council Strategic Flood Risk Assessment ...... 11 EA Product 4 Flood Data ...... 12 Impact of Climate Change ...... 14 4 NPPF Sequential Test and Vulnerability ...... 16 5 Flood Risk Implications for Development ...... 17 Introduction ...... 17 Bridge Soffit Levels...... 17 Conservation of Flood Storage and Flow Routes ...... 17 Surface Water and SuDS ...... 18 6 Conclusions ...... 19

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Tables

Table 3.1: EA Modelled Flood Data ...... 14 Table 3.2: Climate Change – Peak River Flow Allowances ...... 15

Figures

Figure 2.1: Proposed Route Location Plan ...... 4 Figure 2.2: View east along River Thames from Wokingham Canoe Club (showing right bank floodplain) 5 Figure 3.1: EA Flood Zone Map ...... 7 Figure 3.2: EA Flood Risk from Reservoirs Map ...... 8 Figure 3.3: EA Surface Water Flood Risk Map ...... 9 Figure 3.4: Extract of WBC PFRA Map 6.2 – Areas Susceptible to Groundwater Flooding ...... 10 Figure 3.5: WBC SFRA Map 7-5 Character Areas Map 5 of 17 ...... 11 Figure 3.6: Extract of SODC SFRA Figure 2.1 ...... 12 Figure 3.7: EA Product 4 Historical Data ...... 13 Figure 3.8: EA Product 4 Modelled Flood Extents ...... 13 Table 3.1: EA Modelled Flood Data ...... 14

Appendices

Annex A Proposed Route Information Annex B EA Flood Data Annex C WBC, SODC and OCC information

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Executive Summary

This Flood Risk Scoping Assessment has been prepared by Peter Brett Associates LLP, on behalf of our client, Wokingham Borough Council (WBC), to consider the flood risk implications for the proposed ‘New Thames Crossing east of Reading’, a proposed road bridge over the River Thames and Caversham Lakes to the east of Reading.

The assessment will provide input for a Strategic Outline Business Case (SOBC) for the bridge.

For the purpose of the study, the proposed study area is the Thames floodplain corridor within the vicinity of the proposed bridge crossing, from Caversham Lock upstream to Sonning Lock downstream.

The Environment Agency (EA) Flood Zone map shows the proposed route lies within Flood Zone 3 of the River Thames, defined as:

Flood Zone 3 ‘High Probability’ (greater than 1 in 100 (1%) annual probability of river flooding)

The proposed development consists of ‘Essential Infrastructure’ development which is considered appropriate within Flood Zone 3 subject to the Exception Test (ref: (reference National Planning Policy Framework (NPPF) Planning Practice Guidance Table 3).

In considering the feasibility of the proposed development, the following key aspects have been addressed: -

 Vulnerability to flooding from all sources;

 No increased flood risk to third parties as a result of the development.

Flood risk will need to be appropriately mitigated through measures including:

 Proposed bridge soffit levels are set a minimum of 600mm above the modelled 1 in 100 (1%) annual probability plus allowance for climate change level, in accordance with the requirements of Wokingham Borough Council, South Oxfordshire District Council and the EA ‘Flood Risk Assessments: Climate Change Allowances’ guidance;

 Effective bridge design to minimise impacts on floodplain storage and flood flow routes (with the provision of flood compensation measures and potentially flood defence measures);

 Appropriate management of surface water.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

1 Introduction

Scope of Report

1.1.1 This Flood Risk Scoping Assessment has been prepared by Peter Brett Associates LLP, on behalf of our client, Wokingham Borough Council (WBC), to consider the flood risk implications for the proposed ‘New Thames Crossing east of Reading’, a proposed road bridge over the River Thames and Caversham Lakes to the east of Reading linking the A4155 Henley Road/Caversham Park Road junction (via Caversham Lakes access road) north of the river, with Thames Valley Park roundabout south of the river.

1.1.2 The assessment will provide input for a Strategic Outline Business Case (SOBC) for the bridge crossing.

1.1.3 The assessment focuses on assessing the practical flood risk issues at the proposed route as follows:

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

 Assessment of the existing flood risk to the proposed route and the potential impact of the bridge 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.

1.1.4 PBA has many years of experience in, amongst other areas, the assessment of flood risk, hydrology, flood defence and river engineering.

Sources of Information

1.2.1 The FRA has been prepared based on the following sources of flood risk information:

 EA online flood maps (http://maps.environment-agency.gov.uk/wiyby/);

 EA Product 4 data (BE_1214_01);

 The Thames Catchment Flood Management Plan (CFMP), dated December 2009;

 The WBC Preliminary Flood Risk Assessment (PFRA), dated June 2011;

 The WBC Strategic Flood Risk Assessment (SFRA), dated February 2012;

 The Oxfordshire County Council (OCC) PFRA, dated June 2011; and

 The South Oxfordshire District Council (SODC) SFRA, dated July 2013;

 Detailed modelled information based on the existing EA Thames (Reading Complex Change) Flood Alleviation Study (Mapledurham to Sonning reach) (June 2011);

 Topographic data for the site obtained from EA LiDAR data.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Policy Context

1.3.1 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) dated March 2012, issued by Communities and Local Government, the online Planning Practice Guidance released in March 2014 (updated April 2015), and the Environment Agency (EA) ‘Flood Risk Assessments: Climate Change Allowances’ guidance released in February 2016 (updated April 2016);

 Local planning policy contained within the ‘Wokingham Borough Local Development Framework Adopted Core Strategy Development Plan Document’ dated January 2010. Policy CP1 – Sustainable Development states:

‘Planning permission will be granted for development proposals that avoid increasing (and where possible reduce) risks of or from all forms of flooding (including from groundwater).

It is essential that future development is planned carefully… steering it away from areas that are most at risk from flooding and ensuring that it does not exacerbate existing flooding problems.

It is essential that the developer/ applicant consider the possible change in flood risk over the lifetime of the development because of climate change.

SUDS can be used to minimise the risk and impact of flooding. Developers will be expected to provide and fund effective SUDS maintenance regimes. New development should be designed to be resilient to flooding as appropriate’;

• Local planning policy contained within the ‘South Oxfordshire Core Strategy 2027 Development Plan Document’ dated December 2012. Strategy Objective 3: Environment and Design states:

‘This objective seeks quality in the design of all new buildings in its widest sense. It recognises the need to take into account all aspects of climate change including minimising the risks and effects of flooding.’

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

2 Proposed Route Setting

Proposed Route Description

2.1.1 The proposed new crossing route runs from Thames Valley Park Drive in east Reading (OS grid reference 474,190m E, 174,180m N) to the A4155 Henley Road east of Caversham (OS grid reference 473,650m E, 175,650m N).

2.1.2 The proposed route covers part of the River Thames and a water body known as ‘Caversham Lakes’. Although the route is indicative at the current stage, it is assumed likely to tie into an existing access road which runs south-east from the A4155 Henley Road through the Caversham Lakes area; see Figure 2.1 below for the location of the proposed route and the approximate proposed location plan in Annex A.

Figure 2.1: Proposed Route Location Plan

Berry Brook

Caversham Lakes

Sonning Lock

Proposed Bridge Crossing

Caversham Lock Redgrave Pinsent Rowing Lake

River Thames

2.1.3 The proposed route on the south side of the River Thames is situated within Wokingham Borough, while the land on the north side of the watercourse is in South Oxfordshire District.

2.1.4 For the purpose of the study, the proposed study area is considered to be the Thames floodplain corridor within the vicinity of the proposed bridge crossing, between

 Caversham Lock (OS grid ref: 472,050m E, 174,030m N), and;

 Sonning Lock (OS grid ref: 475,240m E, 175,440m N)

2.1.5 The coverage of the floodplain through this area is shown on Figure 3.1.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Proposed Development

2.2.1 The proposal is for a new vehicular bridge on the east side of Reading town centre, linking A4155 Henley Road/Caversham Park Road junction (via Caversham Lakes access road) north of the river, with Thames Valley Park roundabout south of the river, thus providing a third river vehicular crossing between Caversham and Reading town, relieving pressure on the existing Caversham and Reading Bridges.

Topography

2.3.1 ‘Light Detection and Ranging’ (LiDAR) survey information was obtained from the EA to provide an initial indication of ground levels – see PBA Figure 37006_4001_001 in Annex A.

2.3.2 This indicates typical existing ground levels on the access road through Caversham Lakes vary between 36.0m AOD and 36.8m AOD. Levels along the proposed route south of the River Thames range between approximately 35.5m AOD to 36.0m AOD (before rising steeply up to the Thames Valley Park development).

2.3.3 Ground levels at Henley Road (north) and Thames Valley Park Drive (south) are over 37m AOD.

2.3.4 A detailed topographic survey will be undertaken in due course to support any future planning application.

Watercourses and Flood Defences

2.4.1 The River Thames is the dominant watercourse in the study area, flowing south-west to north- east through the area and separating Reading from Caversham. In this location, the River Thames flows south of Caversham Lakes and Marina. The River Thames passes through Caversham Lock approximately 2.5km upstream of the proposed route, and Sonning Lock approximately 1.5km downstream.

Figure 2.2: View east along River Thames from Wokingham Canoe Club (showing right bank floodplain)

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

2.4.2 The Caversham Lakes are a set of lakes – including the Redgrave Pinsent Rowing Lake – created through gravel extraction between Caversham and Sonning Eye, on the north side of the River Thames to the east of Caversham.

2.4.1 The Berry Brook is the smallest main river watercourse in the Borough and emerges as a small drainage channel in an area of residential development in Lower Caversham, to the south of the B3345 Lower Caversham Road. The Brook flows north-east, navigating its way around property boundaries in the area and continuing approximately parallel to the A4155 Henley Road, flowing around the northern side of the Caversham Lakes area – under the existing access road which forms part of the proposed route – and eventually outfalling into the River Thames approximately 1 kilometre downstream of Sonning Lock and Weir.

2.4.2 The River Kennet is the largest tributary of the River Thames, outfalling into the watercourse at Kennetmouth, approximately 1.25km upstream of the proposed crossing.

2.4.3 An unnamed land drainage channel emerges from Thames Valley Park to outfall into the Thames.

Geology

2.5.1 The British Geological Society (BGS) online geology viewer provides the following information on the geology of the proposed route.

 Bedrock: ‘Seaford Chalk Formation and Newhaven Chalk Formation (undifferentiated) - Chalk’

 Superficial Deposits: ‘Alluvium - Clay, Silt, Sand and Gravel’ covers the south of the proposed route. ‘Langley Silt Member - Clay and Silt’ covers the north of the proposed route. The deposits under the lakes which surround the proposed route are ‘Kempton Park Gravel Formation - Sand and Gravel’.

2.5.2 The Cranfield University online ‘Soilscapes’ website provides an overview of the drainage potential of land across Britain. This indicates the proposed route falls within two areas of designation:

 The northern part of the proposed route is designated as ‘Freely draining slightly acid but base-rich soils’;

 The southern part of the proposed route is designated as ‘Loamy and clayey floodplain soils with naturally high groundwater’.

2.5.3 The PBA Controlled Waters Impact Appraisal Report (August 2016) indicates the groundwater in the Chalk Aquifer is expected to be in continuity with the River Terrace Deposits and partially connected with the Alluvium and the River Thames. The groundwater flow direction is expected to be towards the east or south east according to the local hydrogeological map.

2.5.4 The proposed route lies within a high sensitivity area. The site is underlain by a Secondary A Aquifer associated with the superficial deposits and by a Principal Aquifer associated with the underlying White Chalk Subgroup. Part of the northern section of the site lies within groundwater Source Protection Zone (SPZ) 3 (‘Total Catchment’) and Zone 2 (‘Outer Zone’).

2.5.5 The groundwater receptors in the vicinity of the site are therefore considered to be of high sensitivity since the proposed route is underlain by an SPZ2 supporting groundwater abstraction well for public supply and a Principal Aquifer supporting a nearby river ecosystem.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

3 Overview of Flood Risk

EA Flood Maps

Flood Zone Map

3.1.1 The first phase in identifying whether a site is potentially at risk of flooding is to consult the EA’s online Flood Zone map (Figure 3.1). This provides an initial indication of the probability of fluvial/tidal flooding to an area, which is refined by the use of more detailed site-specific level survey and modelled flood levels.

Figure 3.1: EA Flood Zone Map

Site location

© Environment Agency copyright and database rights 2016. © Ordnance Survey Crown copyright. All rights reserved. Environment Agency, 100026380. Contains Royal Mail data © Royal Mail copyright and database right 2016.

3.1.2 The Flood Zone map indicates that the proposed route lies within Flood Zone 3 ‘High Probability’ (greater than a 1 in 100 (1%) annual probability of river flooding). Part of the proposed route along the existing access road is raised above the Flood Zone 3 floodplain and is located in Flood Zone 2 ‘Medium Probability’ (between 1 in 100 (1%) and 1 in 1000 (0.1%) annual probability of river flooding).

EA Flood Risk from Reservoirs Map

3.1.3 The EA provide a map showing the risk of flooding in the event of a breach from reservoirs, based only on large reservoirs (over 25,000 cubic metres of water) – see Figure 3.2. This map confirms that the area is at risk of flooding from such sources, as it forms part of the wider residual risk area if a breach occurred in the Redgrave Pinsent Rowing Lake.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Figure 3.2: EA Flood Risk from Reservoirs Map

Site location

3.1.4 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. As such, the residual risk of such an occurrence is considered to be very low, if not negligible.

EA Surface Water Flood Risk Map

3.1.5 The EA provide a map online showing the risk of surface water flooding. Figure 3.3 shows that the proposed route predominately lies in an area at ‘Very Low’ risk of flooding from surface water (i.e. less than 1 in 1000 (0.1%) annual probability of surface water flooding).

3.1.6 There is a ‘Low’ risk of flooding from surface water flooding (defined as between 1 in 1000 and 1 in 100 annual probability of flooding) in the area south of the Thames, as denoted by the light blue shading in the central part of the proposed route.

3.1.7 There is a small localised area of ‘High’ risk by the Thames Valley Park Drive roundabout (defined as greater than 1 in 30 annual probability of flooding).

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Figure 3.3: EA Surface Water Flood Risk Map

Proposed Route

Wokingham Borough Council Preliminary Flood Risk Assessment

3.2.1 WBC is defined as a ‘Lead Local Flood Authority’ (‘LLFA’) under the Flood and Water Management Act 2010 for the land south of the River Thames. The first step of the Flood Risk Regulations is for LLFAs to produce a ‘Preliminary Flood Risk Assessment’ (‘PFRA’), providing a high level overview of flood risk from all sources within a local area, including consideration of surface water, groundwater, ordinary watercourses and canals.

3.2.2 The WBC PFRA was updated in June 2011 and provides flood risk information on a borough- wide scale; see Figures located in Annex C. The information of specific relevance to the proposed route is as follows:

 PFRA Map 5.1 ‘Historical flooding incidents from local sources of flooding’ indicates that no historical flood events have been recorded at the proposed route and surrounding area;

 PFRA Map 6.1 ‘Flood Map for Surface Water’ indicates minimal surface water flooding at the site. The mapping is superseded by the latest EA Surface Water Flood Risk Maps;

 PFRA Map 6.2 ‘Areas Susceptible to Groundwater Flooding – proportion susceptible’ (see Figure 3.4) indicates the site is located at a medium (>=50% < 75%) to high (>= 75%) risk of surface water flooding. However as PFRA Map 5.1 indicates, there is no evidence of historical flooding incidents at the site.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Figure 3.4: Extract of WBC PFRA Map 6.2 – Areas Susceptible to Groundwater Flooding

Proposed Route

 PFRA Map 6.3 ‘Areas susceptible to groundwater flooding – flooding type’ shows the proposed route is located within ‘Clearwater (consolidated aquifers) flooding;

Oxfordshire County Council Preliminary Flood Risk Assessment

3.3.1 OCC is defined as the LLFA for the land north of the River Thames. The OCC PFRA provides a high level screening exercise which involves collecting information on historic and potential future floods for the county. The information of specific relevance to the proposed route is as follows:

 PFRA Figures 1 and 2 show records of surface water flooding across the study area. This indicates no records of flooding in the vicinity of the site;

 The PFRA also includes flood maps for surface water, but these do not highlight any particular flooding issues at the site are have been superseded in any case by the new EA surface water flooding methodology on which the data in Section 3.1 is based;

 PFRA Figure 7 ‘Areas Susceptible to Groundwater Flooding’ (see AnnexC) shows the proposed route to be located in an area identified as high (‘<75%’) potential susceptibility to groundwater flooding. It is noted that this is based on a relatively coarse analysis (ratings are provided per 1 kilometre square area).

Wokingham Borough Council Strategic Flood Risk Assessment

3.4.1 As noted in Section 1.2, the WBC SFRA was updated in February 2012; see Figures located in Annex C. The information of specific relevance to the proposed route is as follows:

 SFRA Map 6a-1 ‘Overview of Historical Fluvial Flooding (1947-1990)’ shows the proposed route to have been at least partly affected in the 1947, 1974, and 1977 flood events;

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

 SFRA Map 6a-2 ‘Overview of Historical Fluvial Flooding (1991-2009)’ shows the proposed route to have been at least partly affected in the 2000, 2003 and 2007 flood events;

 SFRA Map 7-5 ‘Character Areas Map 5 of 17’ shows the proposed route to be entirely located within Flood Zone 2 or 3, consistent with the EA Flood Zone map (Figure 3.1). The ‘Flood Zone 3a with climate change’ extent shows the entire proposed route to be located within the zone.

Figure 3.5: WBC SFRA Map 7-5 Character Areas Map 5 of 17

Site location

South Oxfordshire District Council Strategic Flood Risk Assessment

3.5.1 The SODC Strategic Flood Risk Assessment (SFRA) was updated in July 2013; see Figures located in Annex C. The information of specific relevance to the proposed route is as follows:

 SFRA Figure 2.1 ‘Flood Zone Map’ (see Figure 3.6) shows the proposed route to be located in Flood Zone 3 ‘High Probability’ (shaded blue) with some areas located in Flood Zone 2 ‘Medium Probability’ (shaded light blue), consistent with the EA Flood Zone map (Figure 3.1).

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Figure 3.6: Extract of SODC SFRA Figure 2.1

Site Location

 SFRA Figure 5.1 ‘Flood Map for Surface Water’ shows the proposed route is not impacted in the 1 in 200 annual probability surface water flood extent.

 SFRA Figure 8.1 ‘Historical Flooding’ indicates the proposed route and surrounding area are located within historic flood extents.

EA Product 4 Flood Data

3.6.1 The EA have provided detailed flood risk information at the proposed route of the bridge crossing and for the surrounding area; see copy of Product 4 data (EA ref: BE_1173_02) in Annex B.

Historic Flood Extents

3.6.2 The provided EA historic flood data shows that the whole proposed route flooded in the 1947 flood, which is accepted as the most severe flood of the 20th Century on this part of the River Thames – see Figure 3.7.

3.6.3 Other flood events to have impacted part of the proposed route include 1974, 1977, 1992, 2000, 2002 and 2007.

3.6.4 The Thames Valley Park Drive roundabout and Henley Road, to which the new road would connect to the south and north respectively, are not indicated to have been impacted in any of the provided flood events.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Figure 3.7: EA Product 4 Historical Data

Modelled Flood Data

3.6.5 The EA have provided modelled flood data for the area from the Reach 3 of the Thames (Reading Complex Change) Flood Alleviation Study completed using 2D modelling software in June 2011. The modelled flood extents in the vicinity of the proposed route are shown in Figure 3.8.

Figure 3.8: EA Product 4 Modelled Flood Extents

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

3.6.6 Figure 3.8 indicates:

 The northern part of the proposed route (along the access road) is located on a nominal ridge of land predominantly outside the 1 in 100 (1%) annual probability floodplain but within the 1 in 1000 (0.1%) annual probability flood extent, therefore is classified as Flood Zone 2;

 The southern part of the route, which passes over the rowing lake, the main River Thames channel and the land on the southern part of the proposed route lies mostly within the 1 in 5 (20%) annual probability flood extent (shaded purple), therefore likely to be considered as Flood Zone 3b ‘Functional Floodplain’.

3.6.7 The associated modelled flood levels across the proposed route are as detailed in Table 3.1, taken from the 2D modelled floodplain flood levels across the proposed route.

Table 3.1: EA Modelled Flood Data

Level (m AOD) for 2D grid cells

Flood Event (Annual Northern Southern Site Centre Probability) Boundary Boundary (Flood Point 6) (Flood Point 1) (Flood Point 13) 1 in 5 (20%) - - 36.11

1 in 20 (5%) - - 36.29

1 in 100 (1%) 36.34 36.35 36.48

1 in 100 (1%) plus 20% 36.50 36.53 36.63 allowance for climate change 1 in 1000 (0.1%) 36.72 36.73 36.82

3.6.8 A comparison has been undertaken of the LiDAR topography data and the modelled flood levels. This indicates the following:

 Isolated areas of the north of the proposed route (along the access road) are affected to shallow depths of less than 100mm in the current 1 in 100 (1%) annual probability flood event, increasing to depths of up to 300mm in the 1 in 100 (1%) annual probability plus 20% allowance for climate change.

 In the south of the proposed route, the flood levels indicate in the current 1 in 100 (1%) annual probability flood event, the land is impacted by up to 500mm depths of flooding, increasing to 700mm in the 1 in 100 (1%) annual probability plus 20% allowance for climate change event.

Impact of Climate Change

3.7.1 In considering flood risk to the proposed route, it is necessary to fully consider the potential impacts of climate change for the lifetime of the development within the mitigation measures. In February 2016 the EA released new guidance on the application of climate change allowances in flood risk assessments:

https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

3.7.2 This guidance provides contingency allowances for potential increases in peak river flow in Table 1, and for potential increases in rainfall intensity in Table 2. The latter requires consideration in any surface water drainage strategy for new development and is discussed in Section 5.4.

3.7.3 The peak river flow allowances table provides a range of allowances based on percentile (i.e. the degree of certainty of an event occurring, based on the range of climate change scenarios assessed through scientific investigations). The provided allowances are also subject to the vulnerability classification of the proposed use and the ‘river basin district’ of the proposed route.

3.7.4 The conditions at the proposed route and consequent peak river flow climate change allowances to be considered are as detailed in Table 3.2.

Table 3.2: Climate Change – Peak River Flow Allowances

Range of Climate Change Flood Risk Allowances River Basin District Flood Zone Vulnerability requiring Classification consideration (2070–2115)

2 +35% to +70% Essential Thames Infrastructure 3a/3b +70%

3.7.5 PBA have obtained the EA 1D-2D hydraulic model and undertaken an initial re-run of the model using scaled up peak river flows for the +70% climate change scenario.

3.7.6 The provisional outputs were analysed at the proposed route and provided provisional estimated peak climate change flood levels in the 1 in 100 annual probability plus 70% event of approximately 37.0m AOD. This would be subject to further analysis of the hydraulic model, potential model improvements and submission of the results to the EA for review and approval.

3.7.7 The estimated 1 in 100 annual probability plus 70% climate change flood level is used as a benchmark in the consideration of mitigation measures at the feasibility stage, as discussed in Section 5.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

4 NPPF Sequential Test and Vulnerability

4.1.1 NPPF PPG ‘Flood Risk and Coastal Change’ Table 2 confirms the ‘Flood risk vulnerability classification’ of a proposed route, depending upon the proposed land usage. This classification is subsequently applied to PPS 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.

4.1.2 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.

4.1.3 The analysis undertaken in Section 4 confirms that the proposed route lies in Flood Zones 2, 3a and 3b and proposals are classed as ‘Essential Infrastructure’ (‘Essential transport infrastructure (including mass evacuation routes) which has to cross the area at risk.’). Such development is considered appropriate in Flood Zone 2, and appropriate in Zones 3a and 3b subject to the Exception Test.

4.1.4 As the development is not in Flood Zone 1, the Sequential Test would also be required. The Sequential Test is a planning-led exercise to demonstrate to WBC and SODC that there are no ‘reasonably available alternative sites’ for the development at lower probability of flooding.

4.1.5 The Exception Test is set out in NPPF paragraph 102, which states:

“…For the Exception Test to be passed:

it must be demonstrated that the development provides wider sustainability benefits to the community that outweigh flood risk, informed by a Strategic Flood Risk Assessment where one has been prepared; and

a site-specific flood risk assessment must demonstrate that the development will be safe for its lifetime taking account of the vulnerability of its users, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall.”

4.1.6 The details provided within the future FRA will address the second part of the Exception Test and demonstrate that the bridge crossing is safe for its lifetime.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

5 Flood Risk Implications for Development

Introduction

5.1.1 The analysis undertaken in Section 4 confirms that the proposed route lies in Flood Zones 2 ‘Medium Probability’, 3a ‘High Probability’ and 3b ‘Functional Floodplain’.

5.1.2 The following section provides an overview of the implications and potential opportunities/ constraints to inform the evolving design.

5.1.3 A detailed FRA will be required to accompany any future planning application for the proposed route. This will utilise the base information provided within this Scoping Assessment and will require further refinement in order to (i) fully consider the impact of the development proposals, (ii) set out the proposed mitigation measures, and (iii) provide a greater level of detail in terms of the proposed surface water drainage strategy.

Bridge Soffit Levels

5.2.1 The EA requirement is for bridge soffit levels to be set a minimum of 600mm above the modelled 1 in 100 annual probability plus suitable allowance for climate change flood level.

5.2.2 On the basis of the provisional 1 in 100 annual probability plus 70% allowance for climate change level of 37.0m AOD (see Section 3.7), this implies a minimum soffit level of 37.6m AOD.

5.2.3 Navigation freeboard requirements are also a key consideration when determining soffit levels for structures crossing a watercourse. The EA Waterways Office at the Wallingford Office confirmed (via a phone call held on 06/07/16) that there are no specific headroom constraints in this particular location of the River Thames. However, the Officer noted that the headroom clearance above Reading Bridge and the new (pedestrian and cycle) Christchurch Bridge is 4.57m, so any new bridge should match this level of headroom at the centre of the navigation channel(s).

5.2.4 The Standard Head Water Level (SHWL) for Sonning Lock is 35.146m AOD, which provides a required minimum headroom clearance to an elevation of 39.716m AOD (i.e. a minimum of 2.116m above the flood level). Therefore, the navigation requirement to provide 4.57m above SHWL will provide the overriding design requirement for the bridge crossing over the River Thames channel.

5.2.5 Away from the main channel on either bank, the climate change allowance level will become the key design factor in relation to impacts on flood flow routes and floodplain storage, discussed further in Section 5.3.

Conservation of Flood Storage and Flow Routes

5.3.1 Any new development located in the vicinity of a watercourse should be constructed such that it does not detrimentally impact on flow routes or reduce the available floodplain storage over a site; either of which could potentially cause an increase in flood levels on-site or elsewhere. This is considered up to the benchmark of the 1 in 100 (1%) annual probability plus allowance for climate change fluvial flood level.

5.3.2 As such, for all elements of the structure within the floodplain of the modelled 1 in 100 (1%) annual probability plus 70% allowance for climate change flood event it is recommended that the soffit of the structure across the floodplain is set no lower than this reference flood level, and ideally a minimum freeboard of 300mm above the flood level to minimise impacts on both flood storage and flow routes.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

5.3.3 Any loss in floodplain storage capacity due to the proposed development (including bridge abutments, bridge landings, ramps and steps and widening or level increase of the existing access road) requires the provision of floodplain compensation on a level-for-level basis.

5.3.4 Such impacts should be minimised as far as practicable through effective design – i.e. construction on stilts/piers to reduce the effective footprint area any maintain flow routes through the area – but there will remain a ‘non-floodable’ element at the bridge landings and from the (albeit) small footprint of the support structure that will require compensation.

5.3.5 Due to the sensitivity of the scheme traversing the whole of the River Thames floodplain, it will also be necessary to incorporate the impacts of the structure into the EA River Thames model to verify that the proposed works do not result in an increase to flood levels and potentially impact on third parties. Should such an impact be identified then the works may also require incorporation of flood defence measures alongside compensation works as mitigation.

Surface Water and SuDS

5.4.1 The NPPF recognises that flood risk and other environmental damage can be managed by minimising changes in the volume and rate of surface runoff from development sites, and recommends that priority is given to the use of Sustainable Drainage Systems (SuDS) in new development, this being complementary to the control of development within the floodplain.

5.4.2 As the intention of SuDS is to mimic the natural drainage regime of the undeveloped site, the NPPF PPG states the following (consistent with the Building Regulations H3 hierarchy):

...the aim should be to discharge surface water runoff as high up the following hierarchy of drainage options as reasonably practicable: - into the ground (infiltration), - to a surface water body, - to a surface water sewer, highway drain or another drainage system, - to a combined sewer

5.4.3 As such, the feasibility of infiltration should be the initial consideration for disposal of surface water, which is dependent on the ground conditions underlying the site.

5.4.4 As of April 2015, the LLFA has become a statutory consultee on planning applications for surface water management. As the LLFA covering the land north and south of the River Thames, OCC and WBC are respectively responsible for the approval of surface water drainage systems within new development and such guidance will play a key role in determining the acceptability of surface water drainage measures in new development.

5.4.5 The key design criteria for aspects of the surface water drainage system are detailed in the DEFRA document ‘Non Statutory Technical Standards for Sustainable Drainage Systems’.

5.4.6 As there will be an increase in impermeable area, there is a need to provide on-site attenuation. The attenuation should be located outside the floodplain to ensure that surface water attenuation is not compromised during fluvial flood events.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

6 Conclusions

6.1.1 This Flood Risk Scoping Assessment has been prepared by Peter Brett Associates LLP on behalf of our client, Wokingham Borough Council (WBC), to consider the flood risk implications for a proposed new Thames Crossing east of Reading; between Thames Valley Park Drive in east Reading and the A4155 Henley Road east of Caversham.

6.1.2 The assessment will provide input for a Strategic Outline Business Case (SOBC) for the bridge.

6.1.3 The Environment Agency (EA) Flood Zones map and detailed modelling outputs indicate:

 The north-eastern part of the proposed route – along the existing access road – is located within Flood Zone 2 ‘Medium Probability’ (between 1 in 100 (1%) and 1 in 1000 (0.1%) annual probability of river flooding).

 The southern part of the route is located within the 1 in 100 annual probability floodplain and over bodies of water, thus falling within Flood Zone 3 ‘High Probability’ and Flood Zone 3b ‘Functional Floodplain’.

6.1.4 The proposed ‘Essential Infrastructure’ is deemed appropriate development within the Flood Zone in which it is located, subject to the Sequential Test and the Exception Test.

6.1.5 The EA ‘Flood risk assessments – climate change allowances’ guidance requires consideration of increases in peak river flow of +70% for such development in Flood Zone 3a or 3b. PBA have undertaken an initial rerun of the model using this climate change allowance to generate a provisional 1 in 100 annual probability flood plus climate change flood level of 37.0m AOD, which would form the basis of any flood mitigation (subject to reporting, and EA review and approval).

6.1.6 The key mitigation requirements for the new bridge crossing area as follows:

 The setting of the bridge soffit level requires consideration of flood risk and navigation requirements. Maintaining the navigation requirement to provide 4.57m above Standard Head Water Level (SHWL) at 39.72m is 2m above the reference flood level and will therefore provide the overriding design requirement for the bridge crossing over the River Thames channel;

 For all elements of the structure within the floodplain of the modelled 1 in 100 (1%) annual probability plus 70% allowance for climate change event it is recommended that the soffit is set no lower than this flood level, and ideally a minimum freeboard of 300mm above the flood level to minimise impacts on both flood storage and flow routes;

 The impact of the proposed structure to the floodplain – in terms of flow routes and storage capacity – should be minimised as far as practicable through effective design – i.e. construction on stilts/piers. Any loss in floodplain storage capacity due to the proposed development requires the provision of floodplain compensation on a level-for-level basis to demonstrate an overall betterment;

 A surface water drainage strategy will need to be incorporated into the development to ensure no increase in peak runoff rates from the existing (greenfield) rate. The surface water drainage strategy for any development will be prepared using SuDS measures where appropriate and in accordance with the NPPF hierarchy and the requirements of Oxfordshire County Council (OCC) and WBC as the Lead Local Flood Authorities (LLFAs) for the land north and south of the River Thames respectively.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

6.1.7 As the scheme design evolves to a suitably developed stage, it will be necessary to incorporate the impacts of the structure into the EA River Thames model to verify that the proposed works do not result in an increase to flood levels and potentially impact on third parties. Should such an impact be identified then the works may also require incorporation of flood defence measures alongside compensation works as mitigation.

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Flood Risk Scoping Assessment New Thames Crossing east of Reading

Annex A Proposed Route Information

 3rd Thames Crossing proposed route map

 Figure 37006_4001_001 LiDAR

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New Thames Crossing East of Reading Controlled Waters Impact Appraisal

Annex A Proposed Route Information

Flood Risk Scoping Assessment New Thames Crossing east of Reading

Annex B EA Flood Data

EA Product 4 Data (EA ref: BE_1214_01) dated 5th May 2016

 Flood Zone map

 River Thames defence information

 River Thames model information

 River Thames modelled extents – Map 1

 River Thames modelled in-channel levels

 River Thames modelled extents – Map 2

 River Thames modelled floodplain flood levels

 Historic Flood Map

 Historic Flood data

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New Thames Crossing East of Reading Controlled Waters Impact Appraisal

Annex B EA Flood Data

Product 4 (Detailed Flood Risk) for Thames Valley Park, Reading Our Ref: BE_1214_01

Product 4 is designed for developers where Flood Risk Standing Advice FRA (Flood Risk Assessment) Guidance Note 3 Applies. This is: i) "all applications in Flood Zone 3, other than non-domestic extensions less than 250 sq metres; and all domestic extensions", and ii) "all applications with a site area greater than 1 ha" in Flood Zone 2.

Product 4 includes the following information: Please note:

Ordnance Survey 1:25k colour raster base mapping; If you will be carrying out computer modelling as part of your Flood Risk Flood Zone 2 and Flood Zone 3; Assessment, please read the enclosed guidance which sets out our Relevant model node locations and unique identifiers (for cross referencing to the water requirements and best practice for computer river modelling. levels, depths and flows table); Model extents showing defended scenarios; This information is based on that currently available as of the date of this letter. FRA site boundary (where a suitable GIS layer is supplied); You may feel it is appropriate to contact our office at regular intervals, to check Flood defence locations (where available/relevant) and unique identifiers; (supplied whether any amendments/ improvements have been made. Should you re- separately) contact us after a period of time, please quote the above reference in order to Flood Map areas benefiting from defences (where available/relevant); help us deal with your query. Flood Map flood storage areas (where available/relevant); Historic flood events outlines (where available/relevant, not the Historic Flood Map) and This information is provided subject to the enclosed notice which you should unique identifiers; read. Statutory (Sealed) Main River (where available within map extents); This letter is not a Flood Risk Assessment. The information supplied can be used to form part of your Flood Risk Assessment. Further advice and guidance regarding Flood Risk Assessments can be found on our website at A table showing: i) Model node X/Y coordinate locations, unique identifiers, and levels and flows for http://www.environment-agency.gov.uk/research/planning/82584.aspx defended scenarios. ii) Flood defence locations unique identifiers and attributes; (supplied seperately) If you would like advice from us regarding your development proposals you can iii) Historic flood events outlines unique identifiers and attributes; and complete our pre application enquiry form which can be found at iv) Local flood history data (where available/relevant). http://www.environment-agency.gov.uk/research/planning/33580.aspx

Red Kite House, Howbery Park, Wallingford, Oxon OX10 8BD Customer services line: 08708 506 506 Email: [email protected] www.environment-agency.gov.uk Flood Map for Planning centred on Thames Valley Park, Reading Created on 05/05/2016 REF: BE_1214_01

Kilometres 0 0.3 0.6

Legend

Main River Flood defences Areas benefiting from flood defences Flooding from rivers or sea (FZ3) Extent of extreme flood (FZ2) Flood Map - flood storage areas

Flooding from rivers or sea without defences (Flood Zone 3) shows the area that could be affected by flooding: - from the sea with a 1 in 200 or greater chance of happening each year - or from a river with a 1 in 100 or greater chance of happening each year.

The Extent of an extreme flood (Flood Zone 2) shows the extent of an extreme flood from rivers or the sea with up to a 1 in 1000 chance of occurring each year.

© Environment Agency copyright and / or database rights 2015. All rights reserved. © Crown Copyright and database right. All rights reserved. Environment Agency, 100024198, 2015. Contact Us: National Customer Contact Centre, PO Box 544, Rotherham, S60 1BY. Tel: 08708 506 506 (Mon-Fri 8-6). Email: [email protected] Defence information BE_1214_01

Defence Location: No defences on Main River

Description: This location is not currently protected by any formal defences and we do not currently have any flood alleviation works planned for the area. However we continue to maintain certain watercourses and the schedule of these can be found on our internet pages.

Model: Thames (Mapledurham to Sonning) 2011

Description: The information provided is taken from the Thames (Reading Complex Change) Flood Alleviation Study completed in June 2011. The study was carried out using 2D modelling software (ISIS-Tuflow).

Model design runs: 1 in 5 / 20% AEP; 1 in 20 / 5% AEP; 1 in 50 / 2% AEP; 1 in 100 / 1% AEP; 1 in 1000 / 0.1% AEP and 1 in 100+20% / 1% AEP with climate change

Mapped Outputs: 1 in 5 / 20% AEP; 1 in 20 / 5% AEP; 1 in 50 / 2% AEP; 1 in 100 / 1% AEP; 1 in 1000 / 0.1% AEP and 1 in 100+20% / 1% AEP with climate change

Model accuracy: Levels ± 250mm

06100_MN_FOLa5

!( Kilometres 06100_MN_FOLa3 0 0.3 0.6

06100_MN_FOLa2

!( Legend

!( Nodes selection Main River !( 20% AEP Flood Outline 5% AEP Flood Outline 1% AEP Flood Outline 0.1% AEP Flood Outline !( !( !( !( 06100_MN_35.023 06100_MN_FOLa AEP = Annual Exceedance Probability !( 06100_MN_35.035 The probability of a flood of a particular 06100_MN_35a.041 magnitude, or greater, occuring in any !( given year

1%CC = 1% Climate Change extent This is the 1% AEP event with an allowance 06100_MN_35.041 for climate change (+20% on river flows)

06100_MN_35a.046 !( 06100_MN_35.052

The modelled flood levels and flows for the closest most appropriate model node points for your site that are within the river channel are provided below:

Flood Levels (mAOD)

1% AEP (+20% on Node label Model Easting Northing 20% AEP 5% AEP 1% AEP 0.1% AEP river flows)

06100_MN_FOLa5 Thames (Mapledurham to Sonning) 2011 474904 175631 35.86 36.10 36.33 36.49 36.70 06100_MN_35.052 Thames (Mapledurham to Sonning) 2011 473726 174149 36.19 36.35 36.54 36.69 36.87 06100_MN_35.041 Thames (Mapledurham to Sonning) 2011 474110 174520 36.10 36.26 36.46 36.60 36.80 06100_MN_35.035 Thames (Mapledurham to Sonning) 2011 474322 174755 36.03 36.22 36.43 36.58 36.78 06100_MN_35.023 Thames (Mapledurham to Sonning) 2011 474626 174810 35.98 36.18 36.40 36.56 36.76 06100_MN_35a.046 Thames (Mapledurham to Sonning) 2011 473789 174479 35.89 36.16 36.41 36.58 36.81 06100_MN_35a.041 Thames (Mapledurham to Sonning) 2011 474003 174680 35.88 36.13 36.37 36.54 36.76 06100_MN_FOLa Thames (Mapledurham to Sonning) 2011 474093 174827 35.87 36.12 36.36 36.52 36.73 06100_MN_FOLa2 Thames (Mapledurham to Sonning) 2011 474325 175010 35.87 36.12 36.35 36.51 36.72 06100_MN_FOLa3 Thames (Mapledurham to Sonning) 2011 474554 175175 35.86 36.11 36.34 36.50 36.71

Flood Flows (m3/s)

1% AEP (+20% on Node label Model Easting Northing 20% AEP 5% AEP 1% AEP 0.1% AEP river flows)

06100_MN_FOLa5 Thames (Mapledurham to Sonning) 2011 474904 175631 7.97 12.45 15.59 16.93 18.48 06100_MN_35.052 Thames (Mapledurham to Sonning) 2011 473726 174149 164.37 199.95 236.28 256.73 274.16 06100_MN_35.041 Thames (Mapledurham to Sonning) 2011 474110 174520 145.00 160.13 175.91 186.51 195.84 06100_MN_35.035 Thames (Mapledurham to Sonning) 2011 474322 174755 136.47 137.79 139.35 145.60 150.36 06100_MN_35.023 Thames (Mapledurham to Sonning) 2011 474626 174810 136.28 136.01 137.91 145.53 150.09 06100_MN_35a.046 Thames (Mapledurham to Sonning) 2011 473789 174479 93.11 136.33 182.71 212.49 248.35 06100_MN_35a.041 Thames (Mapledurham to Sonning) 2011 474003 174680 100.54 151.84 213.58 253.71 303.01 06100_MN_FOLa Thames (Mapledurham to Sonning) 2011 474093 174827 107.83 168.87 238.75 283.91 331.55 06100_MN_FOLa2 Thames (Mapledurham to Sonning) 2011 474325 175010 85.57 117.99 157.28 186.23 227.74 06100_MN_FOLa3 Thames (Mapledurham to Sonning) 2011 474554 175175 77.29 101.74 129.08 147.75 175.39

Note: Due to recent changes in guidance on the allowances for climate change, the 20% increase in river flows should no longer to be used for development design purposes. The data included in this Product can be used for interpolation of levels as part of an Intermediate level assessment.

For further advice on the new allowances please visit https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances

Kilometres Flood Point 1 0 0.3 0.6 Flood Point 2

Flood Point 4

Flood Point 3 Legend

Main River Flood Point 6 20% AEP Flood Outline 5% AEP Flood Outline Flood Point 5 1% AEP Flood Outline 0.1% AEP Flood Outline

Flood Point 9

Flood Point 7 AEP = Annual Exceedance Probability The probability of a flood of a particular magnitude, or greater, occuring in any Flood Point 8 given year

1%CC = 1% Climate Change extent This is the 1% AEP event with an allowance Flood Point 10 for climate change (+20% on river flows) Flood Point 12

Flood Point 11 Flood Point 13

The modelled flood levels for the closest most appropriate model grid cells for your site are provided below:

flood levels (mAOD)

2D grid cell 1% AEP (+20% on river Model Easting Northing 20% AEP 5% AEP 1% AEP 0.1% AEP reference flows) Flood Point 1 Thames (Mapledurham to Sonning) 2011 473690 175634 No Data No Data 36.34 36.50 36.72 Flood Point 2 Thames (Mapledurham to Sonning) 2011 473637 175553 No Data 36.11 36.36 36.56 36.79 Flood Point 3 Thames (Mapledurham to Sonning) 2011 473698 175404 No Data 36.13 36.37 36.56 36.79 Flood Point 4 Thames (Mapledurham to Sonning) 2011 473850 175376 35.89 36.11 36.35 36.51 36.72 Flood Point 5 Thames (Mapledurham to Sonning) 2011 473757 175197 35.54 36.15 36.40 36.58 36.81 Flood Point 6 Thames (Mapledurham to Sonning) 2011 473961 175090 No Data No Data 36.35 36.53 36.73 Flood Point 7 Thames (Mapledurham to Sonning) 2011 473822 175024 35.52 36.15 36.40 36.58 36.81 Flood Point 8 Thames (Mapledurham to Sonning) 2011 473860 174895 No Data No Data No Data 36.58 36.81 Flood Point 9 Thames (Mapledurham to Sonning) 2011 474009 174888 35.86 36.12 36.35 36.52 36.73 Flood Point 10 Thames (Mapledurham to Sonning) 2011 473862 174703 No Data No Data 36.38 36.55 36.78 Flood Point 11 Thames (Mapledurham to Sonning) 2011 473946 174556 35.88 36.14 36.39 36.56 36.78 Flood Point 12 Thames (Mapledurham to Sonning) 2011 474148 174425 36.11 36.27 36.47 36.61 36.81 Flood Point 13 Thames (Mapledurham to Sonning) 2011 474115 174215 36.11 36.29 36.48 36.63 36.82

This flood model has represented the floodplain as a grid. The flood water levels have been calculated for each grid cell.

Kilometres 0 0.3 0.6

Legend

Main River Historic Flood Outline 1947 1974 1977 1992 2000 2002 2007

The Extent of an extreme flood (Flood Zone 2) shows the extent of an extreme flood from rivers or the sea with up to a 1 in 1000 chance of occurring each year.

Our records show that the area of your site has been affected by flooding. Information on the floods that have affected your site is provided in the table below:

Flood Event Code Flood Event Name Start Date End Date Source of Flooding Cause of Flooding

EA0619470300429 06MarchSpring1947 01/01/1947 12/12/1947 main river channel capacity exceeded (no raised defences) EA0619741100406 06NovemberAutumn1974 01/01/1974 12/12/1974 main river channel capacity exceeded (no raised defences) EA0619770800255 06AugustSummer1977 01/01/1977 12/12/1977 main river channel capacity exceeded (no raised defences) EA0619920900383 06SeptemberAutumn1992 01/01/1992 12/12/1992 main river channel capacity exceeded (no raised defences) EA0620001201025 06DecemberWinter2000 01/01/2000 12/12/2000 main river channel capacity exceeded (no raised defences) EA0620030101819 06JanuaryNewYear2003 23/12/2002 12/01/2003 main river channel capacity exceeded (no raised defences) ea061231448 Eye and Dunsden CP_Fluvial Water 19/07/2007 29/07/2007 main river channel capacity exceeded (no raised defences)

Please note the Environment Agency maps flooding to land not individual properties. Floodplain extents are an indication of the geographical extent of a historic flood. They do not provide information regarding levels of individual properties, nor do they imply that a property has flooded internally.

Start and End Dates shown above may represent a wider range where the exact dates are not available.

Annex C WBC, SODC and OCC information

 OCC PFRA Map 7 – ‘Areas Susceptible to Groundwater Flooding’

 SODC SFRA Map 2.1 – ‘Flood Zones’

 SODC SFRA Map 3.1 – ‘Functional Flood Plain’

 SODC SFRA Map 4.1 – ‘Climate Change’

 SODC SFRA Map 8A.1 – ‘Historical Flooding’

 WBC SFRA Map 7-5 – ‘Character Area Map 5 of 17’

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