ENV0000112C Reading and Caversham Flood Alleviation Scheme

T H A M E S A PPRAISAL PACKAGE

Appendix A: Options Appraisal Report

Prepared for Environment Agency

January 2019

CH2M Elms House, 43 Brook Green, London, W6 7EF United Kingdom

Project Number: 683722CH

Document History

Reference Number: ENV0000112C-CH2-000-O00-RP-GEN-0004 Client Name: Environment Agency This document has been issued and amended as follows:

Version Date Description Created By Verified By Approved By

P01 15/05/2017 Draft

P01.1 30/05/2017 Update of XXXXXXX - Draft only (internal) environmental sections

P01.2 23/01/2018 Update of XXXXXXX XXXXXXX Draft only (internal) environmental XXXXXXX sections

C01 02/02/2018 Approval of draft XXXXXXX XXXXXXX XXXXXXX Option Report

P02 08/01/2019 Update of options for XXXXXXX XXXXXXX XXXXXXX OBC submission

Contents

1 Introduction ...... 3 1.1 Background ...... 3 1.2 Approach & Purpose of this Report ...... 6 2 Business Case Objectives ...... 7 2.1 Development of Objectives ...... 7 2.2 Overall Objectives for the Business Case ...... 7 3 Appraisal Process ...... 9 3.1 Appraisal Process ...... 9 3.2 Assessment Criteria ...... 9 3.3 Stakeholder Cnsultation...... 15 4 Assessment of Short Listed Options ...... 17 4.1 Key Project Constraints ...... 21 4.2 Option 1: Do Nothing ...... 22 4.3 Option 2: Do Minimum ...... 24 4.4 Option 3: Flood defences between Promenade Road and Christchurch Playing Fields ...... 26 4.5 Option 4: Flood defences between Christchurch Playing Fields and Nire Road ...... 32 4.6 Option 5 Flood defences between Promenade Road and Nire Road ...... 40 4.7 Option 6 Flood defences between Waterman Place and Reading Bridge ...... 45 4.8 Option 7 Flood defences between Promenade Road and Nire Road and between Waterman Place and Reading Bridge ...... 50 4.9 Option 8: Reading Bridge Bypass ...... 55 4.10 Cost Benefit Appraisal Summary Table ...... 59 4.11 Project Costs ...... 61 4.12 Appraisal Summary Table of Short List Options ...... 62 4.13 Selection and Details of Preferred Option ...... 67 5 Conclusion & Recommendations ...... 69

Appendix A – Long List of Options (From IA) Appendix B – Outline Design Drawings Appendix C – Do Nothing and Do Minimum Modelling Results Appendix D – Buildability Statement Appendix E – Carbon Modelling Tool Appendix F – Geotechnical Desk study & UXO Assessment Appendix G – Ground Investigation Report Appendix H – Project Costs

Glossary of Terms AA Appropriate Assessment AEP Annual Exceedance Probability AONB Area of Outstanding Natural Beauty BCR Benefit Cost Ratio CFMP Catchment Flood Management Plan ECW Environmental Clerk of Works EQS Environmental Quality Standards ESE Early Supplier Engagement ESAP Environmental Site Appraisal Plan FBC Full Business Case FCERM-AG Flood and Coastal Risk Management Appraisal Guidance FRM Flood Risk Management FRMP Flood Risk Management Plan GI Ground Investigation HRA Habitat Regulations Assessment iBCR Incremental Benefit Cost Ratio LWS Local Wildlife Site NEAS National Environmental Assessment Service OBC Outline Business Case OM Outcome Measure PPG Pollution Prevention Guidelines PRoW Public Right(s) of Way RBC Reading Borough Council RFCC Regional Flood and Coastal Committee SAC Special Area of Conservation SoP Standard of Protection SPA Special Protection Area SSSI Site of Special Scientific Interest UWWT Urban Waste Water Treatment Directive UXO Unexploded Ordnance WFD Water Framework Directive

Executive Summary

This options appraisal report outlines the options assessment for the reduction of flood risk in Caversham, Reading, covering the north bank of the Thames. The south bank is considered separately. Business Case Objectives The objective of this business case was to identify an economically viable option through evaluation of costs and benefits that fully considers the effects of all sources of flood risk within the study area via an updated hydraulic model which also takes into account the Water Framework Directive (WFD) and other environmental considerations. Appraisal Process Short-listed options have been assessed against a wide range of criteria and subject to detailed hydraulic modelling and economic assessment as per Defra Flood and Coastal Erosion Risk Management Appraisal Guidance. Option assessment has also been informed by: • Site visits • Phase 1 Habitat Survey and targeted species surveys • Preliminary Environmental Information Report (PEIR) • Preliminary Water Framework Directive (WFD) assessment • Environmental Site Appraisal Plans • Indicative Landscape Plans • Option Plans • Carbon Modelling • Geotechnical desk study • Ground investigation works • Detailed hydraulic modelling • Advice and input from JacksonHyder as ESE supplier on the project. Assessment of Short-listed Options The six “Do Something” options assessed are: Option 3: Flood defences between Promenade Road and Christchurch Playing Fields, Option 4: Flood Defences between Christchurch Playing Fields and Nire Road, Option 5: A combination of Options 3 and 4, Option 6: Flood defences between Waterman Place and Reading Bridge (south bank), Option 7: A combination of Options 5 and 6, and Option 8: Bypass channel at George Street. Option 4 (Defences from Christchurch Playing Fields to Nire Road) has the highest iBCR, compared to Do Minimum, at 4.1. The iBCR of Option 7 (Defences from Promenade Road to Nire Road on the north bank and from Waterman Place and Reading Bridge on the south bank) compared to Do Minimum is 3.6. However, Option 7 also delivers the greatest value of OM1 benefits (at £137M) and OM2 properties (at 739). Based on appraisal of options against the assessment criteria as detailed in Section 4, detailed hydraulic modelling and economic assessment, Option 7 has been identified as the preferred option. This is based on the option delivering the project objectives in their entirety, including those of wider stakeholders, alongside the delivery of the greatest outcome measures available.

This option has a benefit cost ratio of 5.9 and a raw Partnership Funding Score of 34%. If the required partnership funding and/or project savings of £16.9M cannot be achieved, then the selection of Option 7 as the preferred option will be reviewed and either Option 4 or Option 5 will be progressed instead. Conclusions & Recommendations This options assessment has identified a likely preferred option which satisfies the four main categories of assessment (Technical, Environment, Economic and Social). The current raw Partnership Funding score (without contributions) for Option 7 is 34%. Contributions or savings of £16.9M are required to achieve an adjusted PF score of 100%. These costs contribute towards the Project Costs for Approval of £23.2M (including 50th percentile risk). A contribution of £5M of Local Levy has already been allocated to the project from Thames Regional Flood and Coastal Committee (RFCC). Opportunities to achieve project cost savings will be identified during the details appraisal stage, and additional economic benefits associated with road and infrastructure disruption will be assessed. The recommendation is to seek further engagement with stakeholders on options and funding and undertake required surveys before taking the project forward to the Full Business Case (FBC) stage.

1 Introduction 1.1 Background

Purpose of document: This document forms an Appendix to the Outline Business Case (OBC) for the Caversham scheme. It provides supporting information on the appraisal of options undertaken for future flood risk management of the River Thames in Caversham. It should be read in conjunction with the main business case document and other supporting appendices.

The Reading and Caversham Flood Alleviation Scheme aims to address the high level of flood risk in the wards of Caversham and Abbey in Reading, Berkshire. The scheme would reduce the risk of flooding to 739 residential and 58 commercial properties currently estimated to be at very significant, significant or moderate flood risk, as well as two vehicular crossings (Reading Bridge and Caversham Bridge) which are critical transport links across the River Thames. The project is being developed in close consultation with Reading Borough Council (RBC) and the local community. Caversham is a ward in the town of Reading, situated immediately adjacent to the northern bank of the River Thames, it has a population of 24,000. The ward of Abbey is located on the opposite side of the River Thames, with a population of 13,500.

The River Thames flows to the south of Caversham in a west to east direction, with Christchurch Ditch (a much smaller primarily surface water fed watercourse) running parallel, less than 100m to the north, and joining the River Thames downstream of the Caversham Weir complex. The River Thames is bridged by the A4155 (Caversham Bridge) to the western extent of the study area, B3345 George Street (Reading Bridge) in the centre of the study area and the Caversham Weir complex which is located across the River Thames in the eastern reach of the study area (Figure 1-1). The River Kennet joins the River Thames on the right (southern) bank immediately downstream of the study area. In relation to the Water Framework Directive (WFD), the study area is within the Thames and South Chilterns Management Catchment, and the main water body is the Thames from Wallingford to Caversham. This section of the Thames is designated hydromorphologically as “heavily modified”. The overall Thames river status for this section is Moderate. The River Thames consists of soft and hard bank edges, which may support locations where otter and water vole may be present. Christchurch Ditch has no potential for the presence of otter, water vole or native crayfish1. No ecological designations have been identified within 0.5 km of the study area. A Local Wildlife Site (LWS), Warren Woodlands, is located approximately 1km west of the scheme. No impacts are likely to occur. No European or Nationally designated sites are within 2.5 km of the study area (or sites designated for bats within 30km). The Chilterns Area of Outstanding Natural Beauty (AONB) is located outside the study area, approximately 2.4km to the north-west. The area underlies the Seaford Chalk Formation and Newhaven Chalk Formation (undifferentiated) throughout. The formation is part of the White Chalk Subgroup and is expected to comprise abundant flint seams (Mathers and Smith, 2000) (CH2M, 2017)2. The site lies within the continuous green corridor of the River Thames, which runs through the urban landscape of Reading and widens significantly as it becomes Caversham Lakes in the town’s northeast. The area is dominated by large-scale open hydrological features lined with public green space

1 ENV0000112C-CH2-000-O00-RP-EN-001 (Phase 1 Report, 2017)

2 ENV0000112C-CH2-000-O00-TN-GT-0001 (Geo-technical Report, 2017) 3 and woodland belts, and partially overlooked by the tall buildings of central Reading to the south and residential areas to the north. The area is heavily used for recreational purposes, both within the water itself and along the edges, in the public parks, along footpaths and at restaurants and other businesses. Within 1.5km of the study area, there is a Scheduled Monument (Reading Abbey), three Registered Parks & Gardens (Forbury Garden, Caversham Court Park, and Caversham Park), and ten Conservation Areas (the closest being St. Peters Conservation Area immediately to the west of the study area). None of these sites are located within the study area itself. The proposed works are not expected to affect these designations; however, the assessment of that landscape will provide key guidance for integrating with local character.

Figure 1-1 Caversham Location Map ('Contains Ordnance Survey data © Crown copyright and database rights [2017] Ordnance Survey 100024198’) The main source of flood risk in the study area is fluvial flooding associated with the River Thames, through overtopping and seepage. Surface water from the urban developments to the north of the study area exacerbate the flood risk in Caversham. The current flood map for the study area is shown in Figure 1-2.

Figure 1-2 Caversham Do Minimum Flood Extents ('Contains Ordnance Survey data © Crown copyright and database rights [2017] Ordnance Survey 100024198’) There is a long history of flooding in Caversham, where RBC records show flood events occurred in 2000, 2003, 2007 and 20143. Data from the Royal Berkshire Fire and Rescue Service (RBFRS) shows significant confirmed property flooding in 2014 and 2007. Records from the RBFRS and RBC describe internal flooding at 139 residential properties during the 2007 event4. In 2014, flooding affected over 100 properties (32 of which experienced internal flooding)5 and multiple roads were closed due to flooding. Most of these properties are located in Queens Road, Mill Green, and Send Road, and Amersham Road has also been significantly affected in past flood events. This compares well with modelling results and the topography of the area. This report is part of the Outline Business Case for Caversham which follows on from the Initial Assessment (2015) which assessed the case for a detailed study of flood risk and assessment of shortlisted options. The longlist of options considered at Initial Assessment stage is provided in Appendix A.

3 Reading Borough Council, Local Flood Risk Management Strategy, 2015.

4 Reading Borough Council, Reading Preliminary Flood Risk Assessment, 2011.

5 Reading Borough Council, 2013/14 Winter Flooding Report, 2014. 5

1.2 Approach & Purpose of this Report The purpose of this report is to provide a detailed assessment of the short list flood risk management (FRM) options and the process for selection of the preferred option following options appraisal. The approach adopted in this study is in accordance with the Flood and Coastal Erosion Risk Management Appraisal Guidance (FCERM-AG), with environmental, economic, technical and social criteria assessed. Assessment has also been carried out in line with the 2015-2021 Thames River Basin District Flood Risk Management Plan (FRMP), Catchment Flood Management Plan (CFMP) and Local Flood Risk Management Plan. This report provides a summary of the appraisal process for the improvement of flood risk management (FRM) for Caversham. The report includes the following sections: 1. Introduction – presents the background of why the project work is being undertaken and summarises the previous analysis completed to date. 2. Business Case Objectives – to develop a WFD compliant, economically viable option which fully considers fluvial flood risk via an updated hydraulic model. 3. Appraisal Process – assessment criteria and stakeholder consultation. 4. Assessment of short list options – key project constraints, detailed description of options and appraisal under criteria, benefit cost summary, Appraisal Summary Table, selection and detail of preferred option. The short list options appraised are: - Option 1: Do Nothing: withdrawal of all flood risk management activities - Option 2: Do Minimum: Continuation of existing flood risk management activities - Option 3: Do Something: Flood defences between Promenade Road and Christchurch Playing Fields o Raised defences consisting primarily of embankments and sections of flood wall extending from Promenade Road to the rear gardens at the southern end of Patrick Road, adjacent to Christchurch Playing Fields. - Option 4: Do Something: Flood defences between Christchurch Playing Fields and Nire Road o Raised defences consisting of embankments and flood walls running west to east from the rear gardens of properties at the southern end of Patrick Road, adjacent to Christchurch Playing Fields, to the north-eastern extent of Nire Road. In addition, a bypass channel to the north of Reading Bridge will be required in this option to reduce water levels upstream of Reading Bridge. - Option 5: Do Something: Flood defences between Promenade Road and Nire Road o This option is a combination of Option 3 and Option 4. - Option 6: Do Something: Flood defences between Waterman Place and Reading Bridge o Raised defences consisting primarily of flood walls extending from Waterman Place to Reading Bridge. - Option 7: Do Something: Flood defences between Promenade Road and Nire Road and between Waterman Place and Reading Bridge o This option is a combination of Option 5 and Option 6. - Option 8: Do Something: Bypass Channel at George Street o Bypass channel from the western side of George Street, south of Christchurch Ditch, discharging into the River Thames upstream of Caversham Weir. 6

5. Conclusion and recommendations.

2 Business Case Objectives 2.1 Development of Objectives The objectives established for the Thames Appraisal Package were developed in accordance with the River Thames Catchment Flood Management Plan (CFMP) and reviewed alongside the project scope for Caversham. The overarching objectives for the business case are set out in Section 2.2 as are project environmental objectives which have been used in the environmental scoping assessment and environmental assessment. 2.2 Overall Objectives for the Business Case The overall strategic objectives of the project were identified in the project scope as: • To reduce fluvial flood risk to Reading and Caversham, and consider the effects of all sources of flooding. • To fully consider the effects of fluvial flooding mechanisms within the study area by updating the existing hydraulic model. • To identify an economically viable option through evaluation of costs and benefits. • To consider the Water Framework Directive (WFD) and other environmental opportunities. The objectives of the project were refined and expanded during discussions with Environment Agency and key stakeholders and have been established to direct the development of a sustainable scheme that meets the statutory responsibilities of all parties while aligning with individual organisation policies. Objectives are in line with Thames CFMP and have been agreed with Environment Agency Project Managers. The project objectives are outlined below and have been separated into four broad categories: Environment Objectives • Protect the integrity of the River Thames by delivering environmental, ecological and amenity opportunities; • Ensure that disturbance to the environment and inhabitants is kept to a minimum, and where this is not possible, to deliver an appropriate mitigation; and • Contribute to the creation and improvement of habitat in the study area (Outcome Measure OM4 and sub measures of Outcome Measure OM4a to OM4h). Economic Objectives • Reduce the direct and indirect cost of flood damage; • Reduce the risk of flooding to infrastructure, utilities and businesses; • Recommend an option that can achieve an adjusted Partnership Funding Score of greater than 100%; and • Contribute to Outcome Measures OM1 and OM2. Social Objectives • Reduce the risk of flooding to properties and life; • Move properties to a lower flood risk band (Outcome Measure OM2); and 7

• Improve landscape and recreational opportunities; • Develop an option which is in keeping with, and complimentary to, proposals detailed within the draft Reading Borough Local Plan (2017).

Technical Objectives • Take account of risks of climate change; • Take measures to promote health and safety; • Delivers best practice and meets minimum technical requirements; • Ensure the scheme is deliverable (in engineering terms); • Ensure the scheme is capable of achieving required consents; • Minimise disruption to infrastructure and services during construction; and • Ensure a sustainable maintenance legacy for the scheme.

3 Appraisal Process 3.1 Appraisal Process The Options Appraisal process enables a robust and transparent approach for determining a preferred option for Caversham. At project start-up, the long list options (which are detailed in Appendix A) were reviewed, and the short list options to progress for options appraisal for Outline Business Case were agreed by the project team. The appraisal process considered: the most suitable alignment for flood defences, habitat mitigation (considering likely environmental impacts), buildability, health and safety concerns, and whole life cost implications. 3.2 Assessment Criteria The appraisal of the short-list options need to consider a wide range of criteria to provide the comprehensive assessment necessary for business case approval. The following section outlines the criteria under several headings; Health & Safety, Strategic, Technical, Economic and Environmental, which have been considered and reviewed for the option assessment process. A brief explanation is detailed below as to what the assessment will consider. Health and Safety Consideration of the Health and Safety implications of FRM options is a statutory requirement for all design work. Several specific areas of concern for the scheme, which may create potential problems, were noted. • There is a risk of staff and the public being exposed to contaminated or hazardous waste associated with historic land use in the Christchurch Meadows and Hill’s Meadow area; • The proximity of the defences to power generation and transmission infrastructure presents a risk of electrocution and fire; • The proximity of the public, including residential housing, public open space, existing commercial and industrial activities, and transport routes creates a risk to public safety and that of staff on site; • Provision of safe and easy access for future maintenance of any works is required to reduce residual risk to the end user. • Close proximity of George Street (B3345), Hill’s Meadow car park, and several other highways presents a risk to staff and road users (particularly in relation to people / plant interaction). • Working alongside watercourses A Preliminary Unexploded Ordnance (UXO) Assessment was undertaken, meeting the requirements of CIRIA C681 ‘Unexploded Ordnance (UXO) – A guide for the Construction Industry’. The site was rated as “Medium” risk and therefore requires further action to reduce the risk to intrusive activities. A detailed UXO assessment was commissioned and provided guidance on recommended measures to be taken before work on site commences. No detail within this assessment provided additional constraints on the selection of options. Strategic - Aligned with Flood Risk Management Plan and Project Objectives The options developed for Caversham have been developed in line with the 2015-2021 Thames River Basin District Flood Risk Management Plan and are aligned with the Thames Catchment Flood Risk Management Plan and the project scope objectives. These are:

• Social o Reduce the risk of flooding to communities where possible. o Raise community awareness and understanding of all sources of flooding. o Enhance recreation and general amenity across the river basin. • Environmental o Protect and enhance biodiversity through flood risk management schemes. o Deliver WFD improvements or/and mitigation measures. o Ensure no significant impact to the historic environment. o Restore naturally functioning river systems where possible. o Promote sustainable land use management to land owners across the catchment to achieve reductions in flood risk. • Economic o Ensure development and redevelopment in areas at risk of flooding is appropriate, does not increase flood risk and reduces risk wherever possible. o Ensure the scheme is consistent with, and where possible achieves or compliments, the objectives of the draft Reading Borough Local Plan (2017). o Promote the use of sustainable drainage systems in development to help reduce pressure on existing drainage networks. Technical - Reduction in Flood Risk The ability of a flood defence to provide the necessary standard of protection in a reliable and consistent manner is an essential consideration for the effective implementation for the options being considered. The inability of a flood defence to operate under all conditions could lead to widespread flooding of properties and infrastructure at, but not limited to: • Amersham Road; • Nire Road; • Mill Green; • Star Road; • Send Road; • Queen’s Road; • Paddock Road; • Thames Avenue; • Brigham Road; • De Montfort Road; and • Lynmouth Road If flood risk to any properties or land is being increased alternative mitigation measures must be provided or consent gained from landowners, and where necessary compensation provided, as per the Land Drainage Act 1991 and Flood and Water Management Act 2010. Technical - Sustainability The determination of whether an option is sustainable considers a variety of perspectives. Continuation of service, effective use of land, carbon footprint, whole life power demands, future

10 maintenance, and requirement to regularly deploy an operations team for effective management all contribute to the long-term sustainability of structures and assets. Technical - Adaptive Approach for Flood Defence Adaptive management of flood risk offers significant benefits for the project through efficiencies in cost and material use achieved by greater understanding of the future flood risk. Periodic review of the climate change impacts will allow upgrade of flood defences, and all options will be designed in accordance with the Adapting to Climate Change – Advice for Flood and Coastal Risk Management Authorities guidance document. To enable cost effective adaption or upgrade of options, design should consider and incorporate flexibility where possible, to avoid full scale re-construction should future intervention be necessary. Technical - Buildability The buildability of a flood risk management scheme is dictated by the specific location and type of flood defence or assets under consideration. Construction within close proximity to important services and infrastructure will complicate construction and increase the programme and cost of the works. Work within Caversham may place restrictions on the timing and methodology of construction activities due to the proximity of residential properties and public open space, as well as the intended use of well used transport routes. Works may also be restricted by the seasonal sensitivity of any protected species and habitat areas identified by Phase 2 (presence / absence) surveys. Access can impose constraints on how construction is undertaken, with preference for access routes that use less congested parts of the transport network or impose less impact on existing properties and buildings in close proximity to access routes. Similarly, construction which involves significant heavy civil engineering works in close proximity to existing properties and buildings, or main railways, roads, and bridges will be constrained by the need for safe working zones and minimising the impact from noise, vibration and dust. A draft buildability statement has been prepared by an ESE supplier, from Lot 4 of the WEM Framework and is included in Appendix D. Environmental - Habitat Regulations Assessment and Ecology “In accordance with the Habitat Regulations6, all English competent authorities, including Natural England, must undertake a formal assessment of the implications of any new plans or projects which are capable of affecting the designated interest features of European Sites7 before deciding whether to undertake, permit or authorise such a plan or project”. (Natural England, 2016). The Habitat Regulations require the following process to be followed for all plans and projects proposed, if they have the potential to affect a European or Nationally designated site8: 1. Formal Screening: for any Likely Significant Effects (either alone or in combination with other plans or projects), known as Habitat Regulations Assessment (HRA). 2. Appropriate Assessment (AA): required to ascertain whether an adverse effect on the integrity of the site can be ruled out, in the case that these effects cannot be excluded. 3. Compensatory Measure: required when an adverse effect cannot be ruled out, and no alternative solutions can be identified.

6 The Conservation of Habitats and Species Regulations 2010, Statutory Instrument No. 490.

7 European sites comprise Special Areas of Conservation (SACs) designated under Council Directive 92/43/EEC, Special Protection Areas (SPAs) designated under the Wild Birds Directive (Council Directive 79/409/EEC) and Ramsar sites designated under the Ramsar Convention on Wetlands, 1971.

8 Natural England Standard: HRA Habitats Regulations Assessment (HRA) (NESTND026). Available on: http://publications.naturalengland.org.uk/publication/8740045, accessed 24/ 05/ 2017. 11

For the Reading and Caversham FAS, there are no ecological designations within the study area. A Local Wildlife Site (LWS), Warren Woodlands, is located approximately 1km west of the scheme. No impacts are likely to occur. No European or Nationally designated sites are within the study area (or sites designated for bats within 30km). No Formal Screening/HRA is required. The impact of the project on the existing and potential ecology of the study area will be assessed within this section for each option. Environmental - Historic Environment Opportunities/Impact Options will be assessed for their impact upon the historic environment. There are two listed features that could be affected by the options proposed for the Reading and Caversham FAS9: • Grade II listed building, Caversham War Memorial, reference 1445141 (GR: SU 7174 2653) located along the west side of Option 4; and • Grade II listed building, Dean’s Farm Cottage, reference 1156224 (GR: SU 7274 5347) located adjacent to the east side of Option 5. Considerations should be taken in the case of finding or impacting un-recorded archaeology, due to the following known records10: • Scheduled Monument, Reading Abbey: a Cluniac and Benedictine monastery and Civil War earthwork, reference 1007932 (GR: SU 71714 73609). In addition, there are a number of other listed buildings which could be affected by altered conveyance of flood waters: • Grade II listed building, West Memorial Hall, reference 1321953 (GR: SU 7174 4773); • Grade II listed building, Caversham Baptist Free Church, reference 1113562 (GR: SU 7174 4578); • Grade II listed building, Ivy Farmhouse, reference 1113490 (GR: SU 7274 3953); • Grade II listed building, Vaulted Structure in Garden of No 4, reference 1113553 (GR: SU 7274 4849); • Grade II listed building, 2 & 4 Paddock Road, reference 1302882 (GR: SU 7274 5347); • Grade II listed building, 6 Paddock Road, reference 1302883 (GR: SU 7274 4849); • Grade II listed building, St John's Lodge, reference 1321890 (GR: SU 7274 4849); • Grade II listed building, Dean's Farmhouse, reference 1321905 (GR: SU 7274 5347); • Grade II listed building, 8 Paddock Road, reference 1113554 (GR: SU 7274 4849); and • Grade II listed building, Kings Meadow Swimming Pool, reference 1391153 (GR: SU 7197 7397). Further archaeological work depends on the option selected. Across the majority of the scheme, there is a low risk of archaeological features being encountered, or heritage assets being affected by the scheme. Environmental - Water Framework Directive (WFD) Opportunities/Impact A Preliminary WFD Assessment has been undertaken for the full possible extent of defences in combination (i.e. Promenade Road to Nire Road, Waterman Place to Reading Bridge, and the Reading Bridge Bypass).

9 https://www.historicengland.org.uk/listing/the-list/map-search?clearresults=true

10 https://www.historicengland.org.uk/listing/the-list/list-entry/1007932 12

Artificial and Heavily Modified Water Bodies (A/HMWB) have a target to achieve ‘Good Potential’, recognising their important uses, whilst ensuring that the WFD water body is protected as far as possible. To comply with the WFD, works must not cause deterioration of the water body status/potential and must not prevent a water body from meeting good ecological status/potential. Two WFD-designated surface water bodies fall within the scheme boundaries as part of the Thames RBMP. These are riverine water bodies and are Thames (Wallingford to Caversham) (Water Body ID: GB106039030331); and Thames (Reading to Cookham) (GB106039023233). In addition, there are two other watercourses – Christchurch Ditch and Berry Brook – which fall within the scheme boundary and flow into the Thames. The River Thames, specifically Wallingford to Caversham (GB106039030331), is classified as ‘heavily modified’. Its general status is Moderate, showing a Moderate Ecological potential due to its potential being Moderate in relation to Biological quality elements, Physico-chemical quality elements and Supporting elements. The Chemical status of the River is Good. The waterbody also includes WFD protected areas under the Habitats, Nitrates, and Urban Waste Water Treatment (UWWT) Directives, which means that they need to meet the objectives of these directives as well to comply with WFD. The downstream waterbody is the section Thames (Reading to Cookham) (GB106039023233), which is also a ‘heavily modified’ river. Its general status is Moderate, showing a Moderate Ecological potential due to its potential being Moderate in regard to Physico-chemical quality elements and Supporting elements. The Chemical status of the River is Good. The waterbody also includes WFD protected areas under the Nitrates, and Urban Waste Water Treatment Directives, which means that they need to meet the objectives of these directives as well to comply with WFD. Geomorphological/hydromorphological impacts will be considered and WFD catchment mapping of possible sites for potential improvement will be assessed during detailed design of the preferred option. Environmental - Geotechnical and Geo-Environmental Risk Assessment of the geotechnical and geo-environmental risk covers two broad topics. The geotechnical assessment examines the suitability of ground conditions for the construction or modification of flood defence works, and the level of confidence in the ground information collected. This is largely determined by the amount of previous ground information collected along the option alignments. The geo-environmental aspect considers the potential for works to encounter contaminated land / Made Ground or other materials (e.g. asbestos) and the environmental risks associated with this. Assessment of geotechnical and geo-environmental risk is informed by a geotechnical desk study (refer to Appendix F). Key to options assessment in Caversham is the influence of seepage and the water table, together with the assumed weak and compressible strata of alluvium material. At present, this is based on observations during previous flood events, understanding of the groundwater table gained from historical records and boreholes in the surrounding area, past experience of similar projects in the area, and theoretical characteristics of alluvium material. Intrusive Ground Investigation (GI) has been undertaken and the findings related to this will be used to verify the technical viability of the outline design. A report documenting these findings is provided in Appendix G. The geo-environmental risk of each potential option is assessed by the potential release of contaminants from waste disposal and land fill sites, as well as historic land use. Historical mapping indicates there is the potential for Made Ground to be present across the majority of the site, with the following areas of greatest concern:

• Undulating and raised ground at Hill’s Meadow. Although no formal records have been identified which confirm the timing and nature of these materials, anecdotal evidence suggests that this area was used for depositing waste and general fill in the 1950s11; and • Contamination sources (soil and groundwater) associated with former industrial areas to the western extent of the study area, north of Christchurch Ditch, between Wolsey Road and Christchurch Playing Fields. There are no current or historic landfills identified within the study area. However, a large historic landfill site, Richfield Avenue landfill, is located upstream near Caversham Bridge, on the south bank of the River Thames. Recent exploratory holes through the landfill noted no obvious landfill liner, and one of three groundwater samples had boron levels in excess of its relevant Environmental Quality Standards (EQS). There is therefore potential for groundwater contamination downstream of this site, although this is not expected to extend significantly into the study area. Environmental - Land Take and Land Use Change The potential land take of a defence or habitat creation scheme is an important factor in the options appraisal and development process. Areas in which embankments are proposed are primarily located on public land and/or land owned by RBC. Where flood alleviation works are proposed on land owned by private landowners, consideration shall be given for potential delays due to liaison, access and agreements to be made. Compensation damages may be required for private lands, with higher compensation costs associated with some existing land uses; e.g. residential dwellings or commercial activity. Residential dwellings can be found throughout the study area, running parallel to the proposed defence alignments. Commercial properties are also located throughout the study area, with significant potential for temporary disruption. Environmental - Landscape and Visual Amenity This is an assessment of the impact of each option on the location’s landscape character and visual amenity, where the receptors to change are the visitors/occupiers of certain viewpoints (for visual effects) and the landscape resource itself (for landscape effects). With regard to the site location, this will include views taken in by residents to the immediate north and by visitors to recreational amenities throughout the Thames corridor, including the Thames Path National Trail and Thames and Kennet Marina. It will also include the Thames corridor itself as a landscape receptor. Caversham is located south-east of the Chilterns Area of Outstanding Natural Beauty (AONB); the AONB is not expected to be affected by the works. There are also ten conservation areas surrounding the study area, with St. Peters Conservation Area directly adjacent to the west of the study area, bordering with Christchurch Playing Fields. These designations will be shown on the Environmental Site Appraisal Plan (ESAP). The proposed works are not expected to affect the character of these Conservation Areas, including St. Peters; however, the assessment of that landscape will provide key guidance for integrating with local character. The site lies within the continuous green corridor of the River Thames, which flows through the urban landscape of Reading and widens significantly as it becomes Caversham Lakes in the town’s northeast. The area is dominated by large-scale open hydrological features lined with public green space and woodland belts, and partially overlooked by the tall buildings of central Reading to the south and residential areas to the north. Environmental - Recreation and Amenity Impacts to recreation and amenity use are assessed by considering the effect of options on access to public open space and Public Rights of Way (PRoW), river users, and other recreational activities within the study area. The study area is heavily used for recreational purposes, both within the water itself

11 https://www.reading-forum.co.uk/forum/viewtopic.php?f=38&t=2863 14 and along the edges, in the public parks, along footpaths and at restaurants and other businesses. There are also tennis courts, a football pitch, boat club, BMX track and skate park within the study area. Direct impact to the public footpaths or recreational use of the area may require additional consultation and consents for the project at a later stage and may require mitigation measures. Significant temporary disruption and disturbance is envisaged, particularly at Christchurch Meadows and Playing Fields, Hill’s Meadow, Amersham Road Recreation Ground, the Thames Path along the south bank, and the PRoW to the south of Mill Green properties. Economic - Economic Benefits Assessment The economic analysis will be carried out as per FCERM-AG, taking into consideration the monetary value associated with direct property flood damage and indirect damages such as road disruption and risk to life, health, and emergency response. The options will be assessed in comparison to a baseline (Do Nothing), a Benefit Cost Ratio (BCR) and an incremental BCR (iBCR) calculated, to inform the economic viability of the scheme. A partnership funding calculation will be undertaken using the Defra/Environment Agency Partnership Funding Calculator Tool. Availability of potential funding sources, including eligible partnership funding, will also be considered for the likely preferred option. Economic - Whole-Life Costs Whole-life cost comprises outline estimates of capital cost based on an estimate of the costs provided by JacksonHyder through Early Supplier Engagement. The cost estimate has been developed based on the outline design drawings provided in Appendix B, site visits, and further clarifications provided where requested. A Detailed risk register has been produced and subject to a Monte Carlo Risk Analysis to determine the 50th percentile and 95th percentile risk allowances. This criterion also includes outline estimates of maintenance costs based on broad understanding of the potential challenges facing each option throughout the design life of the project. Political Drivers and Stakeholder Ambitions This assessment considers political drivers and key stakeholder ambitions, for example; RBC and local Member of Parliament and how these may influence the option (e.g. increase cost of option, influence timings). This considers the requirement for approvals and consents, and an assessment of the challenges and issues related to gaining these approvals and consents. Opportunities to develop a project with wider benefits beyond flood risk management will be explored in consultation with other stakeholders. This will include working with the local authority to ensure any synergies with the Local Plan, and any geographical similarity with other projects in the area which may enable efficiency savings, are identified. 3.3 Stakeholder Cnsultation An initial meeting was held at Environment Agency offices, Reading, on 26th April 2017 to present the short list options for Reading and Caversham and to seek comments and input from RBC on the options development. Following this meeting, and receipt of further information from RBC, a site visit was held on 12th July 2017 to discuss specific flood mechanisms in the study area and to discuss site constraints associated with construction and intrusive GI works. A working groups and steering group was subsequently established with RBC to continue this engagement, with meetings held throughout 2017 and 2018. A stakeholder analysis was undertaken to identify those who both retain an interest in the scheme and would be impacted by the scheme. A stakeholder management plan was subsequently developed and updated during the OBC stage. Key identified stakeholders included: • Private landowners 15

• RBC (various departments) • Caversham Go Local On a Better Environment (GLOBE) group • Fields in Trust • Local residents All identified stakeholders were consulted and/or informed of the scheme and proposed intrusive GI works prior to these works commencing. The scheme was generally well received with no significant negative impact, and stakeholders broadly supportive of proposals. This consultation included two rounds of public consultation events, targeted at both directly impacted landowners and the wider public. These events were held in June/July 2018 and December 2018. Internal Environment Agency stakeholders, such as NEAS, have been consulted during options development. NEAS Stakeholder objectives principally concerned maximising opportunities for enhancement and protection of the existing recreational areas and key landscape features. Further consultation has included an initial approach to all utility providers regarding the proposals, and a site visit to gain input from local environmental groups (Caversham GLOBE, Reading Tree Wardens).

4 Assessment of Short Listed Options

In accordance with the FCERM Appraisal Guidance, the short list needs to consider do-nothing, do- minimum, sustain and improve options. The long list options from the Initial Assessment (detailed in Appendix A) were reviewed during a programmatic workshop during project start-up and the short list options to progress for options appraisal for Outline Business Case were confirmed. The short list for consideration in this appraisal is as follows: • Option 1: Do Nothing: All maintenance activities cease. (This option would not meet project objectives but is required as per FCERM-AG to provide a baseline against which to measure benefits of other options). • Option 2: Do Minimum: Continuation of the existing annual maintenance regime, but without upgrades. This primarily relates to ongoing inspection and monitoring of assets and reactive clearance of blockages. • Option 3 Do Something: Flood defences between Promenade Road and Christchurch Playing Fields and a bypass channel below Reading Bridge, on the north bank of the River Thames. • Option 4: Do Something: Flood defences between Christchurch Playing Fields and Nire Road and a bypass channel to the north of Reading Bridge, on the north bank of the River Thames. • Option 5: Do Something: Flood defences between Promenade Road and Nire Road and a bypass channel to the north of Reading Bridge, on the north bank of the River Thames. • Option 6: Do Something: Flood defences between Waterman Place and Reading Bridge, on the south bank of the River Thames. • Option 7: Do Something: Flood defences between Promenade Road and Nire Road and a bypass channel to the north of Reading Bridge, on the north bank of the River Thames, and flood defences between Waterman Place and Reading Bridge, on the south bank of the River Thames. • Option 8: Do Something: Creation of a bypass channel to the north of Reading Bridge to the River Thames through Christchurch Meadows and Hills Meadows. Opportunities to deliver wider benefits have been considered in relation to the outline design of each option. These opportunities include channel restoration and habitat creation of Christchurch Ditch in Christchurch Meadows, improving habitat diversity and provision of an educational trail in Hill’s Meadow and planting / landscaping opportunities throughout public open space. A cost allowance for delivering these improvements has been included at this stage, with outline design planned at detailed appraisal. The location and alignment of the short-listed options are detailed in plan drawings in Appendix B. The hydrological and hydraulic modelling results for the Do Nothing and Do Minimum scenarios are detailed in Appendix C, and the assessment of carbon-modelling for Options 1 to 5 is presented in Appendix E. The following section firstly details the key project constraints that are applicable to all options, and then sequentially assesses each of the short list options under the criteria outlined in Section 3.2. This is followed by an Economic Summary Table presenting the economic appraisal outcome for each of the options. The Appraisal Summary Table of Short List Options then gives a high-level summary of the main findings for each of the options. Figures 4-1, 4-2, 4-3, 4-4, 4-5, 4-6 and 4-7 show key locations for the shortlisted options assessed.

Figure 4-1 Western extent of wall alignment at Christchurch Meadows, including the existing fence beside Promenade Road

Figure 4-2 Western extent of Christchurch Meadows, including existing access to Reading University Boating Club

Figure 4-3 Looking east along defence alignment at Christchurch Meadows, George Street (northern approach to Reading Bridge) behind trees in distance

Figure 4-4 Existing raised, made ground to the north of Hill’s Meadow car park 19

Figure 4-5 Public footpath immediately to the south of Mill Green properties, River Thames to left of photograph

Figure 4-6 Looking south-west through Amersham Road Recreation Ground, the defence alignment will run in front of the properties on the right 20

Figure 4-7 Existing perimeter fence along the northern extent of Amersham Road Recreation Ground

4.1 Key Project Constraints A number of risks and constraints have been identified which have the potential to impact on the delivery, cost, programme and success of the project at various stages. Where possible, these risks will be resolved or reduced through outline design and detailed appraisal. The impact of any residual risk will be incorporated within the project risk register and subject to a Monte Carlo risk analysis. • Seepage beneath defence and surface water – existing ground conditions consist of alluvium and gravel layers beneath the proposed flood defences. Seepage through these layers is a known issue and will need to be considered to ensure any scheme performs effectively. Surface water run-off in the Caversham area, combined with the seepage, present an additional flood risk which may require a cut-off and/or temporary storage or pumping during a flood event. • Groundwater – high groundwater levels, and seepage (as detailed above), has the potential to increase construction costs due to water ingress into excavations and requirement for the construction of temporary haul roads in the event that soft ground is encountered. • Recreation and Amenity – Christchurch Meadows, Christchurch Playing Fields, and Hill’s Meadow all offer significant recreational and amenity value to local residents and general public. Options 3 to 6 require works in these areas – works will need to minimise disruption and where possible enhance these locations. • Existing landscape – Options will need to consider any adverse visual and landscape changes and keep these to a minimum and/or mitigate if necessary. Advanced work during the appropriate seasons could be done to clear vegetation, both invasive species and habitat, including translocation where necessary.

• Ecology – Mature trees suitable for foraging/commuting bats and hedgerows present throughout the site. • Highways and PRoWs – Options are likely to cause temporary disruption to the existing highway network and may require temporary closures of PRoWs. The buildability of options will need to be considered and keep this disruption to a minimum with mitigation where necessary. In addition, traffic issues in Reading town centre may affect deliveries and outputs which will affect the programme of works. • Private landowners – elements of the design are located adjacent to, or within, land owned by private landowners. Issues can be varied and high volume, resulting in extensive communication and site-specific reinstatement/mitigation measures. • Underground services – An existing 33kV high voltage cable and a gas main are known to run beneath the proposed defence alignment for Option 3 and 5, and the Reading Bridge Bypass alignment for Option 4, 5, and 7. In addition less critical services are evident elsewhere in the study area. Temporary and permanent disturbance will need to be considered to ensure the risk is managed appropriately. • Contaminated Land – Existing raised, made ground in Hill’s Meadow poses a potential source of contamination, as well as historic industrial land use in the west, and an existing petrol station at George Street. • Benefits and funding – Outcome Measures achievable are unlikely to gain a raw Partnership Funding (PF) score of 120% or greater and therefore Partnership Funding availability is likely to be key. 4.2 Option 1: Do Nothing This option would not meet project objectives but is required as per FCERM-AG to provide a baseline against which to measure benefits of other options. The option is defined as a walkaway scenario wherein all flood risk activities, including maintenance and flood warnings, cease, resulting in increased flood risk. To represent this for Caversham this has been modelled with a 20% increase in channel roughness, 300mm depth of siltation in the River Thames and 50% blockage of Christchurch Ditch Culvert at Reading Bridge. The predicted onset of flooding for this scenario is approximately at an event with a 20% annual exceedance probability (AEP), rising to a 50% AEP at the end of the appraisal period. Health and Safety Increase in flood risk and unmaintained structures would lead to unacceptable rise in health and safety risk to both operatives and members of the public. Key risks include: • Unstable and insecure structures (particularly existing culverts); • Deep, fast-flowing water (in and out of bank) with potential for floating debris; • Debris blocking existing culverts and bridges causing earlier onset of flooding in vulnerable areas Strategic - Aligned with Thames River Basin District Flood Risk Management Strategy and Project Objectives This option does not meet the objectives of the strategy, nor does it meet the project objectives.

Technical - Reduction in Flood Risk This option would increase flood risk through increased channel roughness, blockage of structures and non-maintenance of structures. The option may result in an increase in the risk of sudden and catastrophic flooding related to the failure of defences and assets. Technical – Sustainability This option is not sustainable as it does not manage flood risk which is one of the objectives of this project. Wider damages related to the impact on critical infrastructure and recreational facilities mean the concerns extend far beyond flood risk management. Technical - Adaptive Approach for Flood Defence This criterion is not applicable for this option. Technical – Buildability This criterion is not applicable for this option. Environmental - Habitat Regulations Assessment and Ecology A ‘Do Nothing’ scenario could have potentially adverse impacts on the ecological integrity of the River Thames at Caversham. The quality of surrounding public land may deteriorate due to a lack of maintenance. Option 1 could have potentially negative impacts on ecological values through increased risk of an environmental incident due to non-maintenance. The risk of ecological impacts may increase over time as flood risk increases with climate change and existing flood prevention assets deteriorate due to a lack of maintenance. Known water quality issues in Christchurch Ditch could also be exacerbated. Environmental - Historic Environment Opportunities/Impact A ‘Do Nothing’ scenario would likely cause continued and increasing flood risk throughout Caversham, which could affect listed buildings and scheduled monuments (refer to Section 3.2.8) in low-lying areas close to the Thames. Environmental - WFD Opportunities/Impact Due to the scale of Christchurch Ditch, the amount of discharge and silt into the River Thames under a Do Nothing scenario is likely to be negligible. There is unlikely to be any deterioration to WFD elements. Environmental - Geotechnical and Geo-environmental Risk The Do Nothing scenario could result in increased risk of sedimentation through ceasing maintenance works (e.g. on Christchurch Ditch) and an increasing flood risk over time. An increase in the frequency, depth and extent of flooding has the potential to expose the public and receiving environment to an increased risk of geo-environmental risk associated with highways and contaminated land at Hill’s Meadow. Environmental - Land Take and Land Use Change Urban, residential/suburban and recreational land would be affected by increased flood risk due to a lack of maintenance. Existing areas proposed for development and re-development may be negatively impacted by the decision to adopt a Do Nothing scenario, affecting the future prosperity of the benefit area. Environmental - Landscape and Visual Amenity A lack of regular maintenance is likely to result in silt build-up in and encroachment of ruderal vegetation into the Christchurch Ditch. Previous baseline observations also indicate that this

23 vegetation would be a trap for litter and a target for fly-tipping. These changes would have an adverse effect on the local character and visual amenity by increasing the frequency of elements with low quality within the landscape. Environmental - Recreation and Amenity A lack of maintenance may have negative impacts on the quality of recreational areas and amenity for the local community. Increased flood risk would likely affect the accessibility and quality of recreational and public land, including the Christchurch Playing Fields and the north bank waterfront area. Economic - Economic Benefits Assessment The whole life benefits of the Do Nothing option are £0. This is the baseline option. Economic - Whole-Life Costs The whole life costs of the Do Nothing option are £0. This is the baseline option. Political Drivers and Stakeholder Ambitions An option which increases flood risk is not acceptable to the key stakeholders on this project. 4.3 Option 2: Do Minimum The Do Minimum scenario represents the continuation of current activities to reduce flood risk in Caversham. This includes direct maintenance of the channel and structures as well as operational response to flood events such as clearance of trash screens and culverts. The predicted onset of property flooding for this scenario is currently approximately at an event with a 10% AEP, but will increase to a 33% AEP at the end of the appraisal period. The modelled flood extents for this option can be seen in Appendix C. Health and Safety Flood risk to people from deep, fast flowing flood water in and out of bank would increase over time due to the effects of climate change, posing an increased risk to health and public safety in Caversham. Strategic - Aligned with Thames River Basin District Flood Risk Management Strategy and Project Objectives This option aligns with the “Preparing for Flood Risk” objective of the Thames FRMS by continuing maintenance to reduce flood risk (from Do Nothing). Technical - Reduction in Flood Risk This option does not reduce flood risk compared to the present day situation. Flood risk would increase over time due to climate change. Table 4-1 - Summary of properties at risk for Option 2 - Do Minimum (present day)

Moderate Risk Very Significant (Between 0.5% and Significant Risk Risk (5% AEP or 1.33% AEP chance (Between 1.33% and 5% greater chance of of flooding in any AEP chance of flooding flooding in any given given year) in any given year) year) 20% Most Deprived Areas 0 0 0 21-40% Most Deprived Areas 0 0 0 60% Least Deprived Areas 461 262 19

Technical – Sustainability This option is achievable but flood risk will increase over time due to climate change. It has been assumed that do minimum maintenance will persist for the 100 years appraisal period. Technical - Adaptive Approach for Flood Defence This criterion is not applicable for this option. Technical – Buildability This criterion is not applicable for this option. Environmental - Habitat Regulations Assessment and Ecology The risk of ecological impacts may increase over time as flood risk increases with climate change and existing flood prevention assets become inadequate. Environmental - Historic Environment Opportunities/Impact There is a low risk of impacts to historic assets; however, this may increase over time as flood risk increases with climate change and as existing flood prevention assets deteriorate. Environmental - WFD Opportunities/Impact There will be no change as a result of this option. Environmental - Geotechnical and Geo-Environmental Risk There will be no change as a result of this option. Environmental - Land Take and Land Use Change Urban, residential/suburban and recreational land would be affected by increased flood risk over time as a result of climate change. Environmental - Landscape and visual amenity There will be no change as a result of this option. Environmental - Recreation and Amenity Increased flood risk may affect the accessibility and quality of recreational and public land, including the Christchurch Playing Fields and the north bank waterfront area. Economic - Economic Benefits Assessment This option provides good economic benefit when compared with the Do Nothing Scenario with a benefit cost ratio of 678. The avoidance of damages is principally from avoidance of blockages through maintenance and operational response. Economic - Whole-Life Costs Present value whole life costs over 100 years are £79,876 equivalent to £2,080 per year, with an additional £25,000 every 25 years (associated with the operational response to flooding). Political Drivers and Stakeholder Ambitions This option does not meet stakeholder ambitions to reduce flood risk for Caversham as flood risk will increase over time due to climate change impacts.

4.4 Option 3: Flood defences between Promenade Road and Christchurch Playing Fields This option consists of approximately 740 metres of flood defences, beginning with a short section to the west of the car park adjacent to Abbotsmead Place and extending from Promenade Road in the west to Christchurch Playing Fields in the east. The majority of these defences (approximately 560m) will consist of flood walls ranging from 400 – 1200mm in height. Shorter sections of soft defences will be constructed, particularly in the central area, between Cardinal Close and Elliots Way. This flood embankment will be approximately 2000mm in height. The defence will run broadly west to east. Two short sections of flood wall and landscaping works to private gardens will run from the west of Abbotsmead Place car park to Promenade Road. Following this a flood wall which will run adjacent to Promenade Road along the northern boundary of Christchurch Meadows. Approximately adjacent to Cardinal Close the wall will transition into an embankment which will run through Christchurch Meadows until it reaches Elliots Way, a flood wall will then continue along the northern boundary until it reaches high ground in Christchurch Playing Fields. The provision of the embankment between Cardinal Close and Elliots Way is (operating in conjunction with a sluice gate or similar) to isolate a section of Christchurch Ditch form the floodplain. At this location, surface water outfalls discharge into Christchurch Ditch, and this design will enable a strategic location for temporary pumping to both assist in gravity discharge of the surface water network and mitigate the impact of any residual seepage beneath the embankment and adjoining defences. The alignment of the defence and gradient of side slopes will vary to account for local features and to create a visually acceptable asset. Raised embankments will primarily consist of a clay core and fill material forming the shoulders. The flood walls will primarily involve construction of a new concrete core wall, clad to match existing features. Flood gates and stoplogs will be provided at key access points (particularly the University boat club and Wolsey Road) to facilitate day to day access and flow control structures (non-return valve and a vertical sluice) will be provided where the defence crosses Christchurch Ditch to prevent bypass flooding. The embankment will be maintained from the toe to allow a narrower crest and reduce the overall footprint, and it will include a key trench into existing ground to reduce the amount of seepage post- construction. It is assumed maintenance will consist primarily of grass cutting and will be undertaken as part of the wider maintenance of the public open space for efficiency. The outline design drawings can be seen in Appendix B. Health and Safety As part of the solution there will be greatly reduced risk to people from deep, fast flowing flood water out of bank, within the protected residential zone. However, risk to people from deep fast flowing flood water in bank and out of bank in other unprotected parts of Caversham would remain. There are several flood gates and stoplog sections in the scheme. Closing these gates and open sections could be hazardous for the operators if there is flood water present at these locations while they are closing them. To mitigate this, any openings will be closed at the initiation of a flood warning, this will provide sufficient time for all gates to be closed and stoplogs placed, before flood waters arrive. All embankments included in the scheme have been designed with a 2-metre-wide crest to minimise the risk of pedestrians walking along the embankment, be it recreationally or inspection related, falling

26 down the slopes. In addition, these slopes have a gradient of 1 in 4 (≈14⁰) which is appropriate for normal maintenance methods using ride on machines12. A Service diversion may be required for a major underground 33kV electricity line, which passes close to the defence alignment in Caversham Meadows, subject to final design proposals. Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option aligns with the strategy to reduce flood risk to people through delivery of flood risk management schemes. It meets the following objectives from the FRMP: • Reduce the risk of flooding to communities where possible. • Raise community awareness and understanding of all sources of flooding. • Enhance recreation and general amenity across the river basin. • Protect and enhance biodiversity through flood risk management schemes. Technical - Reduction in Flood Risk This option will affect a reduction in flood risk to a 0.5% AEP including the effects of climate change (35% increase in flows). Implementation of this option will move 43 properties to a lower flood risk band (Outcome Measure 2 (OM2)). 10 properties will be moved from the very significant and significant flood risk bands to the moderate and low flood risk band (Outcome Measure 2B (OM2B)). Table 4-3 - Summary of remaining properties at risk for Option 3 – Flood defences between Promenade Road and Christchurch Playing Fields (at end of appraisal period)

Moderate Risk Very Significant (Between 0.5% and Significant Risk Risk (5% AEP or 1.33% AEP chance of (Between 1.33% and 5% greater chance of flooding in any given AEP chance of flooding in flooding in any given year) any given year) year) 20% Most Deprived Areas 42 14 0 21-40% Most Deprived Areas 0 0 0 60% Least Deprived Areas 386 248 8

12 http://www.hse.gov.uk/aboutus/meetings/iacs/aiac/apg/280710/3-3-1-managing-slopes-and-banks.pdf 27

(i.e. overdesigned foundations) this will be investigated further at detailed design and implemented where appropriate. Technical – Buildability For the overall delivery programme, it is suggested the project be split into sections, which will be constructed consecutively in their entirety before proceeding to the next work area. This will minimise disruption on the local highway network, due to the import of materials to site. Completion of the scheme could be expedited by working on several fronts however, this will significantly increase the impact on the local community. Localised access to construct the wall and bund adjacent to the College Car Park (Iceland Building) will be via Iceland’s drive-way and Abbotsmead. For defences along Promenade Road and within Christchurch Meadows access will be established at Promenade Road and Wolsey Road. A haul road will be established for the length of the clad reinforced concrete wall, to distribute all materials to the work front. Local roads will be used to bring materials to satellite access points, using 8-wheel road tippers and flat-bed trucks. These material deliveries will be supervised by Traffic Marshals to help prevent the need for road closures. Hard standings of approximately 10x10m will be installed inside the access points for material laydown and where possible, site dumpers up to 9 tonnes in size will be used to distribute materials from these points to the work front. This segregated delivery system will help to prevent the contamination of local roadways. Groundwater seepage may be an issue due to the granular layers underlaying the site. Significant amounts of ground water will have an impact on the programme of works, to allow for dewatering of excavations. There are known to be underground services along the western end of the alignment in Christchurch Meadows, it will be important to avoid clashes with these key services. Environmental - Habitat Regulations Assessment and Ecology Option 3 is largely located within an area of amenity grassland and broadleaved parkland/scattered trees. The alignments of proposed embankments and flood walls have been optimised to minimise removal of mature trees and other vegetation, as well as address key concerns raised by affected residents, wherever possible. A flood wall will traverse Christchurch Meadows along its northern boundary until it reaches high ground at the Playing Fields. One short section of embankment will be constructed between Wolsey Road and Elliots Way to facilitate pumping from behind the defence in a flood event (to address residual seepage and reduce surface water impacts). In the west of the alignment, individual mature trees may need to be removed in the vicinity of Abbotsmead Place to ensure root systems do not impede the construction of the flood wall or pose maintenance issues. Through the western part of Christchurch Meadows, construction may require removal of trees, most of which are isolated and not mature. Between Promenade Road and Wolsey Road, species-poor hedgerows and tall ruderal fern/herb may also need to be cleared to accommodate the replacement of existing fencelines with flood walls. Where Wolsey Road meets Christchurch Meadow, a flood gate with walls would be constructed to maintain access to the Meadow. Outline design indicates that a large mature tree can be avoided. East of Wolsey Road, at the level of Cardinal Close, the previously culverted drain transitions to the open Christchurch Ditch. This is considered a key opportunity to enhance the benefits of the scheme. Opportunities to improve water quality and the ecological and aquatic integrity of the drainage line are being explored. In this section, the flood wall will continue on the northern side of Christchurch Ditch, requiring approximately three mature trees to be cleared. However, this allows Christchurch Ditch to remain connected to the Meadows. Combined with restoration works to enhance the

28 ecological integrity of the stream, this could enable Christchurch Ditch to become a key feature of this public open space. A preliminary ground level bat roost assessment and subsequent emergence and re-entry survey was undertaken to determine the likely presence of bat roosts. Four trees of high potential were identified in this area. Emergence and re-entry surveys identified three species of bats commuting and foraging within the area, however, no roosts were identified. Best practice construction mitigation should be employed during construction, such as a strategy for sensitive directional lighting. No signs of badger activity were noted in Christchurch Meadows, Christchurch Playing Field or Meadow Park. Christchurch Ditch, which runs along the northern boundary of Christchurch Playing Fields and Hill’s Meadow, offers limited potential for protected species as it remains overgrown and shaded for much of its length. However, it may provide connectivity functions as well as providing shelter and foraging opportunities for animals13. Further information is provided in the PEIR. Environmental - Historic Environment Opportunities/Impact The Caversham War Memorial, a Grade II listed building (shown in Figure 4-8), will not be affected by the proposed works as part of this option. Although compactors and other machinery/equipment required for construction may cause noise and vibration nuisance at nearby residences and businesses, impacts to listed buildings are unlikely due to the distance from the works. Informal consultation with NEAS archaeologists has indicated that a cultural heritage desk-based assessment is unlikely to be required due to the low risk of archaeological features being encountered during works or heritage assets being affected by the scheme. No archaeological artefacts were encountered during GI works. However, it is recommended that any in-channel works are supervised by an archaeological watching brief in the event unrecorded archaeological artefacts are encountered. A Written Scheme of Investigation will be required. Further information is provided in the PEIR.

13 Phase 1 Survey Report (CH2M) 2018 29

Figure 4-8 Caversham War Memorial identified, located 30m adjacent to the south of proposed defences. Environmental - WFD Opportunities/Impact A Preliminary WFD Assessment has been undertaken for this option. Key components of Option 3 include linear defences, control structures and in-channel works to Christchurch Ditch. The linear defences do not pose any risk to the ecological status of the River Thames. Christchurch Ditch is overgrown and shaded for most of its length; the presence of active fish populations is therefore likely to be limited. This option could possibly increase wetland habitats in localised areas where water will stand for long periods during flood creating riparian habitats. There could be localised and temporary disturbance to terrestrial species during construction. However, there is unlikely to be any impact to aquatic species due to the distance between the set-back linear defences and the water body. This option will have in-channel works carried out within Christchurch Ditch, and control flow structures will be established in key points where the ditch passes under the defence. Structures such as non-return valves or vertical sluices where the ditch crosses the defence will ensure bypass flooding (i.e. water flowing from the River Thames via Christchurch Ditch) is avoided. Although these structures may disturb habitat and substrates, there is also an opportunity for increased diversity of macrophyte and invertebrate species post scheme construction. There could be disturbance to fish passage at the downstream extent of Christchurch Ditch where it outfalls to the River Thames at Heron Island. Control structures may introduce issues during low flows, possible siltation of the channel and insufficient discharge to transport sediment naturally, and potential loss of natural substrate and increase in fine sediments. It is considered that this option will not impact on the Habitats Directive, UWWT Directive and Nitrates Directive. Further information is provided in the PEIR.

Environmental - Geotechnical and Geo-environmental Risk Made Ground is present throughout the Caversham site, primarily within the topsoil layer (typically 200 – 300mm), but often extending to >800mm. Geo-environmental issues may be associated with handling and disposing of Made Ground. The area between Wolsey Road and Christchurch Playing Fields is a former industrial site. The presence and extent of contamination is identified within the GI interpretive report. Borrow material for embankments will need to be sourced offsite; sufficient, suitable material is unlikely to be won onsite. Further information is provided in the PEIR. Environmental - Land Take and Land Use Change Temporary impacts to land use will occur during construction of the flood defences. Once operational, impacts to land use will occur during flooding, when Christchurch Meadows is inundated and effectively used for flood water storage. No permanent impacts to land use will occur; flood walls will not affect access to/from or use of land, while embankments in public open space will remain available for use by the public. Moorings alongside the Thames Path may need to be closed temporarily during construction, resulting in revenue losses. Commercial properties, particularly on Fry’s Island and Piper’s Island, may be temporarily impacted by construction works and potential access disruption. Liaison with RBC, which owns Christchurch Meadows, will be critical to this option. Liaison with the Riverside Court Management Company Limited and Berendsen UK Limited will also be required. Further information is provided in the PEIR. Environmental - Landscape and Visual Amenity The flood wall along Promenade Road will introduce a new element to the streetscape, though not necessarily a new characteristic. The proposed wall will have a direct visual comparison to the existing boundary wall along the south-western edge of the road. This existing wall will remain the dominant element of the streetscape, due to its height, as long as the proposed flood wall does not present a visual contrast to it. Therefore, the flood wall should emulate the existing wall in material, colour, mortar colour, bonding pattern, and potentially, the repetitive use of piers. The construction of the flood wall along Promenade Road will result in the loss of several self-seeded sycamore trees – this will have negligible impact on the streetscape. The working area is likely to also require the removal of several mature trees at the boundary with Christchurch Meadows. The loss of these trees will open-up views into the green space, but at no harm to visual quality. A bridge in the foundation should be used to minimise damage to the root zones of mature trees at this boundary, so that tree loss is minimised to the working area only. At Christchurch Meadows, the open characteristic, driven by the views towards the Thames, will be maintained, as will the neat lawns and specimen trees. The boundary to the properties along the edge of the Danall (Christchurch Ditch) will be changed from fence line to brick-clad floodwall. The brick cladding should be locally appropriate in colour and finish. There is anecdotal risk that the proposed wall would become attractive to vandalism; this would have an indirect adverse impact on the quality of the greenspace and the setting to the war memorial. East of Wolsey Road, there is the potential to develop the landscape quality of Christchurch Ditch by clearing ruderal vegetation, restoring natural morphology and improving flow and quality of the water. Further information is provided in the PEIR.

Environmental - Recreation and Amenity Construction of Option 3 would temporarily impact recreational use of the amenity areas due to works and access requirements. Temporary disruption and disturbance is envisaged, particularly at Christchurch Meadows and Playing Fields (including the football pitch, playground and tennis courts), and some sections of access to the river front. No permanent detrimental impacts to access, recreation opportunities or amenity are likely to occur. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option would provide economic benefit of £61,531,717 at a benefit cost ratio of 15.9, with an incremental benefit cost ratio of 1.9 compared to Do Minimum. This option would provide a standard of protection against a flood event with a 0.5% AEP including the effects of climate change and move 43 properties to a lower flood risk band. The current raw Partnership Funding score (without contributions) is 82%. Contributions of £752,045 are required to achieve an adjusted Partnership Funding score of 100%. Economic - Whole-Life Costs Present value whole-life costs are £3,858,423 including maintenance costs. Carbon modelling indicates 2,143 tonnes of carbon for this option. Political Drivers and Stakeholder Ambitions This option meets stakeholder ambitions. This is through reduced flood risk and provision of amenity and ecological benefits. Amenity and environmental benefits arise through the improvement of Christchurch ditch. 4.5 Option 4: Flood defences between Christchurch Playing Fields and Nire Road This option consists of approximately 3,340m of flood defences extending from Westfield Road Recreation Ground in the west, to Nire Road in the east. The majority of these defences will consist of embankments (approximately 1,860m) and flood walls (approximately 1,310m) raised approximately 420 – 1570mm above the existing ground. The remaining length (approximately 376m) is composed of temporary demountable defences located to the north of Christchurch Playing Fields which will be 580mm high. In addition, a 200-metre-long bypass channel beneath Reading Bridge is required to mitigate increased flood risk to properties outside the benefit area. Compensatory storage was considered but found to be technically ineffective due to the lack of appropriate land which is hydraulically-linked to the floodplain lost. The defence will run broadly west to east, an embankment will run from high ground in Westfield Road Recreation Ground to Gosbrook Road, temporary defences will run along Gosbrook Road, an embankment will run along the eastern boundary of Christchurch Playing Fields and through Hill’s Meadows, with a short section of flood wall along the western side of George Street between these two embankments. A flood wall will replace existing walls from Hill’s Meadows along the southern edge of properties on Mill Green to The Causeway, an embankment will pass through the open area south of Paddock Road to Amersham Road Recreation Ground and a flood wall will be constructed around the roadside boundary of Amersham Road Recreation Ground and south of properties on Honey Meadow Close. Another embankment will then run to the east of Nire Road to Ruskin Close, where a flood wall will tie into high ground. A control structure is being proposed at Berry Brook, and will operate in conjunction with temporary pumping to both assist in gravity discharge of the surface water network and mitigate the impact of

32 any residual seepage beneath the adjoining defences. A similar principle is being considered near Heron Island and to the northeast of Dean’s Farmhouse. The alignment of the embankments and gradient of side slopes will vary to account for local features and to create a visually acceptable asset. Where possible, the embankment in Hill’s Meadow will make use of existing raised Made Ground, with the addition of a clay core to reduce seepage. Raised embankments will primarily consist of a clay core and fill material forming the shoulders. The flood walls will primarily involve construction of a new concrete core wall, clad to match existing features. Flood gates and stoplogs will be provided at key access points (particularly to Heron’s Island, Mill Green properties, and the boatyard) to facilitate day to day access and flow control structures (non- return valve and a vertical sluice) will be provided where the defence crosses Christchurch Ditch to prevent bypass flooding. A road ramp (or temporary / demountable measures) will need to be provided immediately to the east of the road junction between Mill Road and Mill Green to facilitate access to Heron’s Island properties (which are not protected by the defence due to raised threshold levels) in the day to day scenario. The embankment will be maintained from the toe to allow a narrower crest and reduce the overall footprint, and it will include a key trench into existing ground to reduce the amount of seepage post- construction. It is assumed maintenance will consist primarily of grass cutting and will be undertaken as part of the wider maintenance of the public open space for efficiency. The outline design drawings can be seen in Appendix B. Health and Safety As part of the solution there will be greatly reduced risk to people from deep, fast flowing flood water out of bank, within the protected residential zone. However, risk to people from deep fast flowing flood water in bank and out of bank in other unprotected parts of Caversham would remain. This is less of an issue than in Option 4 as much less of Caversham is left unprotected. There are several flood gates and stoplog sections in the scheme. Closing these gates and open sections could be hazardous for the operators if there is flood water present at these locations while they are closing them. To mitigate this, any openings will be closed at the initiation of a flood warning, this will provide sufficient time for all gates to be closed and stoplogs placed, before flood waters arrive. All embankments included in the scheme have been designed with a 2-metre-wide crest to minimise the risk of pedestrians walking along the embankment, be it recreationally or inspection related, falling down the slopes. In addition, these slopes have a gradient of 1 in 4 (≈14⁰) which is appropriate for normal maintenance methods using ride on machines14. The sluice at Mill Green, where Christchurch ditch outfalls into the Thames, will required safe access for inspection and maintenance. This will be provided by pouring a set of concrete steps with a handrail, down to a concrete platform in channel, immediately downstream of the sluice. This will allow the sluice to be cleared safely if required. Access for authorised maintenance personnel will be required across the scheme, however, some areas will need to be secured from public access due to private land and public health and safety issues. This is particularly the case for Option 5, which traverses a number of private properties.

14 http://www.hse.gov.uk/aboutus/meetings/iacs/aiac/apg/280710/3-3-1-managing-slopes-and-banks.pdf 33

Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option aligns with the strategy to reduce flood risk to people through delivery of flood risk management schemes. It meets the following objectives from the FRMP: • Reduce the risk of flooding to communities where possible. • Raise community awareness and understanding of all sources of flooding. • Enhance recreation and general amenity across the river basin. • Protect and enhance biodiversity through flood risk management schemes. Technical - Reduction in Flood Risk This option will affect a reduction in flood risk to a 0.5% AEP including the effects of climate change (35% increase in flows). Implementation of this option will move 606 properties to a lower flood risk band (Outcome Measure 2 (OM2)). 258 properties will be moved from the very significant and significant flood risk bands to the moderate and low flood risk band (Outcome Measure 2B (OM2B)). Table 4-4 - Summary of remaining properties at risk for Option 4 – Flood defences between Christchurch Playing Fields and Nire Road (at end of appraisal period)

Moderate Risk Very Significant (Between 0.5% and Significant Risk Risk (5% AEP or 1.33% AEP chance of (Between 1.33% and 5% greater chance of flooding in any given AEP chance of flooding in flooding in any given year) any given year) year) 20% Most Deprived Areas 0 0 0 21-40% Most Deprived Areas 0 0 0 60% Least Deprived Areas 112 11 11

Completion of the scheme could be expedited by working on several fronts however, this will significantly increase the impact on the local community. To enable construction of the defences around Christchurch Playing Fields, access will be established from the north-west corner of Christchurch playing field on Gosbrook Road. Construction access to Reading Bridge bypass channel will be via the north-west corner of Christchurch Playing Fields and Hills Meadow car park. Significant vegetation clearance, including mature trees is required in eastern Christchurch Meadows to enable construction of the bypass channel. Ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. To construct the bypass channel beneath George Street a full closure of George Street will be required. The estimated duration of construction at this location is not expected to exceed 2 weeks, clear diversion routes will be in operation to minimise disruption. Hills Meadow will be accessed from the car park adjacent to George Street and from the end of Mill Road, prior to the Heron Island access road. Access to the rear of the buildings at Mill Green will be achieved from Mill Green in the West and the boat yard to the East, here access will be limited to small plant due to a constrained footpath. Residents access to the rear of these properties will also be removed for the duration of the works. Should access need to be maintained, then a significant temporary works solution would need to be incorporated, which is not currently programmed for. Similar constraints exist at The Causeway and outputs have been reduced to reflect this. For the embankments in the Amersham Road Recreation Ground area, access will be established from The Causeway, Meadow Way and Amersham Road. Amersham Road will also serve as an access point for the Honey Meadow Close wall. A protective matting haul road will run along the length of the Amersham Road Recreation Ground and Honey Meadow Close defences, to allow the distribution of materials from the access points to the work front. Significant vegetation clearance is required through the Honey Meadow Close area, ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. Access to the Nire Road Embankment area will be via the Northern extent of Nire Road, with a protective matting haul road extended to the Northern and Southern extents of the Nire Road embankment for material delivery by dumper. Access via Ruskin will be necessary to construct the wall in this location and marshals used to manage access to properties. Local roads will be used to bring materials to the access points using 8-wheel road tippers and flat- bed trucks, these material deliveries will be supervised by Traffic Marshals. Hard standings of approximately 10x10m will be installed inside the access points for material laydown and where possible, site dumpers up to 9 tonnes in size will be used to distribute materials from these points to the work front. This segregated delivery system will help to prevent the contamination of local roadways. No significant road closures are anticipated in these areas, apart from at George Street. Groundwater seepage may be an issue due to the granular layers underlaying the site. Significant amounts of ground water will have an impact on the programme of works, to allow for dewatering of excavations. Environmental – Habitat Regulations Assessment and Ecology Option 4 is located within a site of amenity grassland with broadleaved parkland/scattered trees from the west of Christchurch Playing Fields to the east and south of the Playing Fields. Poor semi-improved grassland and broadleaved parkland/scattered trees are present on both west and north-east corners of Hill’s Meadow with sections of scrub and tall ruderal vegetation on the north-east corner of Hill’s Meadow. The key ecological risk at Christchurch Playing Fields is the potential loss of notable poplars along the eastern boundary, as well as the loss of hedgerow and other mature trees. The Reading Bridge Bypass would result in the loss of numerous poplars and elms along George Street and significant modification to the heavily modified River Thames. It could result in the potential loss of fish species during construction, and disturbance to habitat and substrate, including nursery, refuges and spawning areas.

A flood embankment will traverse Hill’s Meadow, a former dumping or landfill site, which is characterised by undulating topography. Throughout this area, the proposed defence will, for the most part, involve reinforcing existing raised ground with suitable engineering clay and a watertight geomembrane. Some shrubs will need to be removed to enable construction; however, there will be little material change to the existing environment in Hill’s Meadow. This area also presents an opportunity for ecological enhancement, as well as potential use for environmental or outdoor education. Part of the broadleaved semi-natural woodland along Mill Green may be lost due to a hard defence, which will largely follow an existing footpath from Hill’s Meadow in the west to The Causeway in the east. At the level of Paddock Road, further east of Mill Green, the south section of Christchurch Ditch has a broadleaved semi-natural woodland surrounded by hedge with trees (species-poor), and ruderal vegetation and poor semi-improved grassland on the south. This vegetation is likely to be removed, however mature trees north of the ditch will be retained. Amenity grassland through Amersham Road Recreation Ground will be disturbed, however, this area offers little ecological value. Disturbed areas will be revegetated. In the south-east corner of Amersham Road Recreation Ground, the flood wall will continue into an area of relatively dense woodland south of Honey Meadow Close. Approximately 100m of vegetation will need to be removed and will need to remain cleared to allow maintenance access. In addition to flood defences, the possibility of lowering the ground level through Lowfield Farm (by 1m maximum) is currently being explored. This could increase the compensatory flood storage capacity of the fields and provide a source of material for the embankments. Suitable reptile habitat is present in the eastern section of the proposed scheme and construction would have direct impacts such as direct mortality and temporary habitat loss, and indirect impacts such as disturbance without relevant mitigation measures. Badger activity was recorded throughout the eastern environs of the proposed scheme, extending across from the field east of The Causeway to the south-western corner of Lowfield Farm. One main, two subsidiary, and two outlier setts were noted during the survey within the eastern environs of the proposed scheme. The collective field signs indicate the main route passage from the main sett follows the wooded lakeside edge past Amersham Road Park and up towards Lowfield Farm. Water vole surveys were conducted within Christchurch Meadows and Playing Fields, and within Lowfield Farms and Berry Brook Woods only. No signs of water vole were noted throughout the survey effort and therefore likely absence of was determined from the scheme footprint. Few signs of otter activity were noted within the scheme environs. A single sprainting site was discovered underneath a footbridge in the north-eastern corner of Hills Meadow Park and a single otter resting site (hover) along the edge of the River Thames south-east of Mill Green. A preliminary ground level bat roost assessment and subsequent emergence and re-entry survey was undertaken to determine the likely presence of bat roosts. A total of 19 trees of high potential were identified in this area. Emergence and re-entry surveys identified three species of bats commuting and foraging within the area. Two confirmed roosts were identified in woodland to the south of Lowfield Farm, however, these are considered to be sufficiently outside of the construction area. The poplar trees lining George Street on the north side of Reading Bridge were included in the ecological survey scope and have been confirmed to have low or negligible potential for bat roosts. Best practice construction mitigation should be employed during construction, such as a strategy for sensitive directional lighting. Further information is provided in the PEIR. Environmental - Historic Environment Opportunities/Impact Permanent impacts to the historic environment are not anticipated. There is a low risk that the Grade II listed building (Dean’s Farm Cottage - GR SU 72566 74387) could be affected by machinery use, noise and dust during construction works. The building is immediately adjacent to the alignment of the 36 proposed embankment. Suitable control measures (e.g. exclusion zones) would be required to protect this during construction, particularly due to vibration from compaction machinery/equipment when constructing the embankments. Informal consultation with NEAS archaeologists has indicated that a cultural heritage desk-based assessment is unlikely to be required due to the low risk of archaeological features being encountered during works or heritage assets being affected by the scheme. However, further archaeological investigation is likely to be required for the Reading Bridge Bypass, and if ground levels are to be reduced at Lowfield Farm. Further GI in these areas may need to be supervised by an archaeological watching brief. Further consultation with Berkshire Archaeology would be required for this option. Further information is provided in the PEIR.

Figure 4-9 Dean’s Farm Cottage seen directly adjacent to the proposed defences. Environmental - WFD Opportunities/Impact A Preliminary WFD Assessment has been undertaken for this option. Key components of Option 4 include linear defences, control structures and in-channel works to Christchurch Ditch and the Berry Brook, and creation of a bypass to the north of Reading Bridge. No significant change to ecology of floodplain area is expected. Christchurch Ditch is overgrown and shaded for most of its length; the presence of active fish populations is therefore likely to be limited. This option could possibly increase wetland habitats in localised areas where water will stand for long periods during flood creating riparian habitats. There could be localised and temporary disturbance to terrestrial species during construction. However, there is unlikely to be any impact to aquatic species due to the distance between the set-back linear defences and the water body (Thames Wallingford to Caversham). This option will have in-channel works carried out within Christchurch Ditch and the Berry Brook, and control flow structures will be established in key points where these small watercourses pass under the defence. Structures such as non-return valves or vertical sluices where the ditch crosses the defence will ensure bypass flooding (i.e. water flowing from the River Thames via Christchurch Ditch) is avoided. Christchurch Ditch will discharge the same flow and velocity into the River Thames, and at a higher flow and velocity during a flood event. Although these structures may disturb habitat and substrates, there is also an opportunity for increased diversity of macrophyte and invertebrate species post scheme construction. There could be disturbance to fish passage at the downstream end of Christchurch Ditch where it outfalls to the River 37

Thames at Heron Island. Control structures may introduce issues during low flows, possible siltation of the channel and insufficient discharge to transport sediment naturally, and potential loss of natural substrate and increase in fine sediments. The Reading Bridge Bypass has the potential for significant impacts to natural substrate, river width variation, fish habitat (including refuge, nursery and spawning areas), and constrained, canalised flows. There is an opportunity to increase macrophyte and invertebrate species diversity post construction. Due to the inclusion of the Reading Bridge Bypass, a Detailed WFD Assessment will be required. All components (i.e. linear defences) will be included to ensure cumulative impacts are assessed. Further information is provided in the PEIR. Environmental - Geotechnical and Geo-environmental Risk Made Ground is present throughout the Caversham site, primarily within the topsoil layer (typically 200 – 300mm), but often extending to >800mm. Geo-environmental issues may be associated with handling and disposing of Made Ground. The presence and extent of contamination will be identified following receipt of the GI interpretive report. Traces of asbestos were identified in the GI at Hill’s Meadow. Evidence of trash was also identified, including glass bottles and jars, metal bars and engine pistons. In the event that large debris is uncovered during this process, more excavation (and suitable disposal of the debris) would be required. Further assessment will be required to understand the presence of asbestos throughout Hill’s Meadow. Stripping and excavating into the existing embankments creates a risk of contamination through handling and disposal. There is a risk of potential leaching and migration of contaminants to groundwater from disturbance to Made Ground at Hills Meadow and in Amersham Park due to evidence of hydrocarbons and high groundwater. Borrow material for embankments will need to be sourced offsite; sufficient, suitable material is unlikely to be won onsite. Further information is provided in the PEIR. Environmental - Land Take and Land Use Change Temporary impacts to land use and public access will occur during construction of the flood defences, particularly as much of the scheme extends through public open space (Christchurch Playing Fields, Hill’s Meadow, Amersham Road Recreation Ground). Due to narrow access, works near Mill Green will require a temporary closure of the footpath for the duration of construction, which is estimated as 18 weeks. Once operational, impacts to land use will occur during flooding, when Christchurch Meadows and Playing Fields is inundated and effectively used as flood water storage. No permanent impacts to land use will occur. Moorings alongside the Thames Path may need to be closed temporarily during construction, resulting in revenue losses. Commercial properties, particularly on Fry’s Island and Piper’s Island, may be temporarily impacted by construction works and potential access disruption. If required, compensatory storage at Lowfield Farm could prevent future use of this currently unmanaged land for agricultural purposes. However, the land is classified as 3a/3b under the Agricultural Land Classification and is therefore not considered to be of high value. Liaison with RBC (which owns Christchurch Playing Fields and Hill’s Meadow), as well as landowners north of Heron Island to the south of Mill Green properties, and to the east of Paddock Road, will be critical to this option. Further information is provided in the PEIR.

Environmental – Landscape and Visual Amenity Broadly, Option 4 would introduce new elements to the landscape and result in the loss of vegetation (particularly specimen trees and hedgerows) which contribute to the visual amenity and landscape value of the area. The impact of these new elements varies substantially along the alignment, and in some locations, presents an opportunity for landscape enhancement. For example, at Amersham Road Recreation Ground, the proposed embankment could be incorporated as a play feature. The biggest risk of adverse impacts on the landscape of Christchurch Meadows comes from the risk to mature trees, including veteran trees within the Playing Fields and other prominent specimens specimen trees that have a significant influence on their surrounding environment. Mature trees should be retained, with rootzones avoided to prevent long term damage. At Christchurch Playing Fields, the proposed demountable defences would introduce a repeating element along the footpath and Gosbrook Road. This could be minimised if these are suitably integrated into the environment. When not in operation, the demountable defences will allow the Playing Fields to remain open in character and the important inter-visibility of Elizabeth House and the fields to be maintained. The bypass channel would broadly be in keeping with the existing characteristics of the Thames Corridor and Christchurch Meadows. It will create an additional channel with formalised banks, with reinstated lawns, riverside paths and specimen trees consistent with the area. However, the bypass channel will also result in the loss or disturbance of major landscape characteristics, such as the locally- valued landmark poplar trees along George Street and avenue of elms. The culvert beneath George Street will introduce large facades of concrete, which is not currently seen in the existing environment. Cladding or formwork would be required to minimise this impact. Hill’s Meadow has a naturalistic character, with sinuous edges to woodland blocks against open grass and scrubland. The new embankment will be able to match this character with a rounded shape that mitigates its engineered design, and with appropriate planting. Visual receptors are likely to be limited to recreational visitors within Hill’s Meadow itself. The embankment will not change the nature of the view, mostly replacing like for like in terms of view structure. The risk posed to landscape character along Mill Green comes from the possible introduction of materials that degrade the sensitive ‘historic village’ character that currently exists. To mitigate this, the proposed wall must consist of materials and finishes that are consistent with the localised historic vernacular. There is also a risk to mature trees that contribute highly to the Mill Lane character and a possibility that the enclosure of the lane due to a higher wall reduces its quality as a recreational/historic resource. The embankment south of Amersham is likely to fit well with the naturalistic character of that greenspace. A sinuous embankment with gentle slopes would cause negligible impact to landscape character. Affected views are likely to be limited to recreational visitors to Amersham Road Recreation Ground and its connecting footpaths. These views may experience noticeable changes due to proximity, but the nature of the view will remain consistent, with green elements dominating. The wall along Honey Meadow Close will introduce a new hard element along the residential boundary, but more significantly, result in woodland being cleared to maintain an access corridor along the defence. The partial loss of this block of woodland will have an adverse impact, though the effect will not be widespread. Views from the river will be unaffected; there will be some change in views from Amersham Road Recreation Ground, though not enough to alter the nature of the view; and southerly views from properties on Honey Meadow Close will be opened-up to more sky. The embankment along Lowfield Farm will introduce a new element, yet it will be small compared with the larger scale landscape elements present. A naturalistic shape and vegetation cover will ensure the embankment presents little to no change to character. Most views of the embankment will be filtered through boundary vegetation along the edge of the farm. Views from Caversham Lakes are more open and direct, but with a greater distance and wider panorama, meaning that in context, the change will be barely noticeable. 39

Further information is provided in the PEIR. Environmental - Recreation and Amenity Construction of Option 4 would temporarily impact recreational use of the amenity areas due to construction works and access requirements. Temporary disruption and disturbance is envisaged, particularly at Christchurch Meadows and Playing Fields (including the football pitch, playground and tennis courts), Hills Meadow, and the PRoW to the south of Mill Green properties. The defence along the eastern side of Christchurch Meadows could affect the use of the existing pavilion, currently used by sporting groups. The existing Christchurch Playing Fields currently provides three junior-size football fields. The proposed embankment does not prevent the creation of a single full-size football pitch, as requested by RBC. No permanent detrimental impacts to access, recreation opportunities or amenity are likely to occur. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option would provide economic benefit of £114,936,193 at a benefit cost ratio of 7.7, with an incremental benefit cost ratio of 4.1 compared to Do Minimum. This option would provide a standard of protection against a flood event with a 0.5% AEP including the effects of climate change and move 606 properties to a lower flood risk band. The current raw Partnership Funding score (without contributions) is 45%. Contributions of £9,043,400 are required to achieve an adjusted Partnership Funding score of 100%. Economic - Whole-Life Costs Present value whole-life costs are £14,839,256 including maintenance costs. Carbon modelling indicates 22,118 tonnes of carbon for this option. It should be noted that this figure does not include the construction of Reading Bridge Bypass, as the carbon model was run before the inclusion of the bypass as a complimentary solution. Political Drivers and Stakeholder Ambitions This option meets stakeholder ambitions. This is through reduced flood risk and provision of amenity and ecological benefits. Amenity and environmental benefits arise through provision of a full-sized football pitch in Christchurch Playing Fields. 4.6 Option 5 Flood defences between Promenade Road and Nire Road This option consists of approximately 3,730 metres of flood defences extending from Promenade Road in the west to Nire Road in the east. The majority of these defences will consist of embankments (approximately 1900m) and flood walls (approximately 1480m) raised 400 – 1700mm above the existing ground, to provide a SoP of 0.5% AEP. The remaining length (approximately 376m) is composed of temporary demountable defences located to the north and west of Christchurch Playing Fields and will be 580mm high. In addition, a 200-metre-long bypass channel to the north of Reading Bridge is required to mitigate increased flood risk to properties outside the benefit area. Compensatory storage was considered but found to be technically ineffective due to the lack of appropriate land which is hydraulically linked to the floodplain lost. The defence will run broadly west to east. Two short sections of flood wall and landscaping to private gardens will run from the west of Abbotsmead Place car park to Promenade Road. Following this a flood wall will run adjacent to Promenade Road along the northern boundary of Christchurch Meadows. Approximately adjacent to Cardinal Close the wall will transition into an embankment

40 which will run through Christchurch Meadows until it reaches Elliots Way, a flood wall will then continue along the northern boundary until the boundary of Christchurch Playing Fields. The provision of the embankment between Cardinal Close and Elliots Way is (operating in conjunction with a sluice gate or similar) to isolate a section of Christchurch Ditch form the floodplain. At this location, surface water outfalls discharge into Christchurch Ditch, and this design will enable a strategic location for temporary pumping to both assist in gravity discharge of the surface water network and mitigate the impact of any residual seepage beneath the embankment and adjoining defences. A similar principle is being considered at other locations at the scheme including near Heron Island, to the northeast of Deans Farm Conservation Area, and at Berry Brook. Temporary demountable flood defences will then run along the western edge of Christchurch Playing Fields on a raised footpath, these temporary defences will continue east along Gosbrook Road to the boundary of Christchurch Playing Fields. Following this, an embankment will run along the eastern boundary of Christchurch Playing Fields and through Hill’s Meadows, with a short section of flood wall along the western side of George Street between these two embankments. A flood wall will replace existing walls from Hill’s Meadows along the southern edge of properties on Mill Green to The Causeway, an embankment will pass through the open area south of Paddock Road to Amersham Road Recreation Ground and flood wall will around the roadside boundary of the park and south of properties on Honey Meadow Close. Another embankment will then run to the east of Nire Road to Ruskin Close, where a flood wall will tie into high ground. The alignment of the defence and gradient of side slopes will vary to account for local features and to create a visually acceptable asset. Raised embankments will primarily consist of a clay core and fill material forming the shoulders. Where possible, the embankment in Hill’s Meadow will make use of existing raised, made ground. The flood walls will primarily involve construction of a new concrete core wall, clad to match existing features. Flood gates and stoplogs will be provided at key access points (particularly at the University boat club, Wolsey Road, Heron’s Island, Mill Green properties, the boatyard and Amersham Road Recreation Ground) to facilitate day to day access, and flow control structures (non-return valve and a vertical sluice) will be provided where the defence crosses Christchurch Ditch to prevent bypass flooding. A road ramp will need to be provided immediately to the east of the road junction between Mill Road and Mill Green to facilitate access to Heron’s Island properties (which are not protected by the defence due to raised threshold levels). The embankment will be maintained from the toe to allow a narrower crest and reduce the overall footprint, and it will include a key trench into existing ground to reduce the amount of seepage post- construction. Maintenance will consist primarily of grass cutting and will be undertaken as part of the wider maintenance of the public open space for efficiency. The outline design drawings can be seen in Appendix B. Health and Safety The solution will greatly reduce the risk to people from deep, fast flowing flood water out of bank, in all major residential areas within Caversham. A risk to people from deep fast flowing flood water in bank and out of bank in Christchurch Meadows and Amersham Road Recreation Ground will remain, however this cannot be reasonably mitigated. There are several flood gates and stoplog sections in the scheme. Closing these gates and open sections could be hazardous for the operators if there is flood water present at these locations while they are closing them. To mitigate this, any openings will be closed at the initiation of a flood warning, this will provide sufficient time for all gates to be closed and stoplogs placed, before flood waters arrive. All embankments included in the scheme have been designed with a 2-meter-wide crest to minimise the risk of pedestrians walking along the embankment, be it recreationally or inspection related, falling

41 down the slopes. In addition, these slopes have a gradient of 1 in 4 (≈14⁰) which is appropriate for normal maintenance methods using ride on machines15. The sluice at Mill Green, where Christchurch ditch outfalls into the Thames, will required safe access for inspection and maintenance. This will be provided by pouring a set of concrete steps with a handrail, down to a concrete platform in channel, immediately downstream of the sluice. This will allow the sluice to be cleared safely if required. A Service diversion may be required for a major underground 33kV electricity line, which passes close to the defence alignment in Caversham Meadows. Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option aligns with the strategy to reduce flood risk to people through delivery of flood risk management schemes. It meets the following objectives from the FRMP: • Reduce the risk of flooding to communities where possible. • Raise community awareness and understanding of all sources of flooding. • Enhance recreation and general amenity across the river basin. • Protect and enhance biodiversity through flood risk management schemes. Technical - Reduction in Flood Risk This option will affect a reduction in flood risk to a 0.5% AEP including the effects of climate change (35% increase in flows). Implementation of this option will move 649 properties to a lower flood risk band (Outcome Measure 2 (OM2)). 268 properties will be moved from the very significant and significant flood risk bands to the moderate and low flood risk band (Outcome Measure 2B (OM2B)). Table 4-4 - Summary of properties at risk for Option 5 – Flood defences between Promenade Road and Nire Road (at end of appraisal period)

Moderate Risk Very Significant (Between 0.5% and Significant Risk Risk (5% AEP or 1.33% AEP chance of (Between 1.33% and 5% greater chance of flooding in any given AEP chance of flooding in flooding in any given year) any given year) year) 20% Most Deprived Areas 0 0 0 21-40% Most Deprived Areas 0 0 0 60% Least Deprived Areas 79 11 1

15 http://www.hse.gov.uk/aboutus/meetings/iacs/aiac/apg/280710/3-3-1-managing-slopes-and-banks.pdf 42

Technical - Adaptive Approach for Flood Defence This would be a new flood defence. There are no existing flood defences suitable for adaption in Caversham. Allowance has been made for future predicted climate change increases up to the end of the appraisal period. At present the option is designed to provide a SoP of 0.5% AEP including climate change. Opportunities have been identified to stagger the investment and enable future raising without major capital works, (i.e. overdesigned foundations) this will be investigated further at detailed design and implemented where appropriate. Technical – Buildability For the overall delivery programme, it is suggested the project be split into sections, which will be constructed consecutively in their entirety before proceeding to the next work area. This will minimise disruption on the local highway network, due to the import of materials to site. Completion of the scheme could be expedited by working on several fronts however, this will significantly increase the impact on the local community. Localised access to construct the wall and bund adjacent to the College Car Park (Iceland Building) will be via Iceland’s drive-way and Abbotsmead. For defences along Promenade Road and within Christchurch Meadows access will be established at Promenade Road and Wolsey Road. A haul road will be established for the length of the clad reinforced concrete wall, to distribute all materials to the work front. To enable construction of the defences around Christchurch Playing Fields, access will be established from the North-West corner of Christchurch playing field on Gosbrook Road. Construction access to Reading Bridge bypass channel will be via the north-west corner of Christchurch Playing Fields and Hills Meadow car park. Significant vegetation clearance, including mature trees is required in eastern Christchurch Meadows to enable construction of the bypass channel. Ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. To construct the bypass channel beneath George Street a full closure of George Street will be required. The estimated duration of construction at this location is not expected to exceed 2 weeks, clear diversion routes will be in operation, to minimise disruption. Hills Meadow will be accessed from the car park adjacent to George Street and from the end of Mill Road. Access to the rear of the buildings at Mill Green will be achieved from Mill Green in the West and the boat yard to the East, here access will be limited to small plant due to a constrained footpath. Residents access to the rear of these properties will also be removed for the duration of the works. For the embankments in the Amersham Recreation Ground area, access will be established from The Causeway, Meadow Way and Amersham Road. Amersham Road will also serve as an access point for the Honey Meadow Close wall. A protective matting haul road will run along the length of the Amersham Road Recreation Ground and Honey Meadow Close defences, to allow the distribution of materials from the access points to the work front. Significant vegetation clearance is required through the Honey Meadow Close area, ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. Access to the Nire Road Embankment area will be via the Northern extent of Nire Road, with a protective matting haul road extended to the Northern and Southern extents of the Nire Road embankment for material delivery by dumper. Access via Ruskin will be necessary to construct the wall in this location and marshals used to manage access to properties. Local roads will be used to bring materials to satellite access points, using 8-wheel road tippers and flat-bed trucks. These material deliveries will be supervised by Traffic Marshals to help prevent the need for road closures. Hard standings of approximately 10x10m will be installed inside the access points and site dumpers up to 9 tonnes in size and running on protective matting, will be used to distribute materials from the access points to the work front. This will help prevent the contamination of local roadways.

Groundwater seepage may be an issue due to the granular layers underlaying the site. Significant amounts of ground water will have an impact on the programme of works, to allow for dewatering of excavations. There are known to be underground services along the western end of the alignment in Christchurch Meadows, it will be important to avoid clashes with these key services. Environmental – Habitat Regulations Assessment and Ecology Option 5 is a combination of Options 3 and 4, resulting in flood embankments and walls running from Promenade Road in the west to Nire Road in the west, as well as the construction of Reading Bridge Bypass. Construction of this option will therefore require more vegetation clearance than Options 3 or 4 alone. Additional risks to those presented in Section 4.4.7 and 4.5.7 are detailed below. A preliminary ground level bat roost assessment and subsequent emergence and re-entry survey was undertaken to determine the likely presence of bat roosts. A total of 23 trees of high potential were identified in this area. Emergence and re-entry surveys identified three species of bats commuting and foraging within the area. Two confirmed roosts were identified in woodland to the south of Lowfield Farm, however, these are considered to be sufficiently outside of the construction area. Best practice construction mitigation should be employed during construction, such as a strategy for sensitive directional lighting. Further information is provided in the PEIR. Environmental – Historic Environment Opportunities/Impact Option 5 is a combination of Options 3 and 4. All relevant WFD impacts/opportunities are covered in Section 4.4.8 and 4.5.8. Further information is provided in the PEIR. Environmental – WFD Opportunities/Impact Option 5 is a combination of Options 3 and 4. All relevant WFD impacts/opportunities are covered in Section 4.4.9 and 4.5.9. Further information is provided in the PEIR. Environmental - Geotechnical and Geo-environmental Risk Made Ground is present throughout the Caversham site, primarily within the topsoil layer (typically 200 – 300mm), but often extending to >800mm. Geo-environmental issues may be associated with handling and disposing of Made Ground. The area between Wolsey Road and Christchurch Playing Fields is a former industrial site. The presence and extent of contamination is identified within the GI interpretive report (Appendix G). Traces of asbestos were identified in the GI at Hill’s Meadow. Evidence of trash was also identified, including glass bottles and jars, metal bars and engine pistons. Further assessment will be required to understand the presence of asbestos throughout Hill’s Meadow. Stripping and excavating into the existing embankments creates a risk of contamination through handling and disposal. Borrow material for embankments will need to be sourced offsite; sufficient, suitable material is unlikely to be won onsite. Environmental - Land Take and Land Use Change Option 5 is a combination of Options 3 and 4. All relevant land take and land use change impacts are covered in Section 4.4.11 and 4.5.11. Further information is provided in the PEIR.

Environmental - Landscape and Visual Amenity It is unlikely that the intervisibility between Option 3 and Option 4 would compound to create a more significant impact. All relevant landscape and visual amenity impacts are covered in Section 4.4.12 and 4.5.12. Further information is provided in the PEIR. Environmental - Recreation and Amenity Option 5 is a combination of Options 3 and 4. All relevant recreation and amenity impacts are covered in Section 4.4.13 and 4.5.13. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option would provide economic benefit of £122,000,297 at a benefit cost ratio of 6.9, with an incremental benefit cost ratio of 3.9 compared to Do Minimum. This option would provide a standard of protection against a flood event with a 0.5% AEP including the effects of climate change and move 649 properties to a lower flood risk band. The current raw Partnership Funding score (without contributions) is 40%. Contributions of £11,610,913 are required to achieve an adjusted Partnership Funding score of 100%. Economic - Whole-Life Costs Present value whole-life costs are £17,588,660 including maintenance costs. Carbon modelling indicates 24,261 tonnes of carbon for this option. It should be noted that this figure does not include the construction of Reading Bridge Bypass, as the carbon model was run before the inclusion of the bypass as a complimentary solution. Political Drivers and Stakeholder Ambitions This option meets stakeholder ambitions. This is through reduced flood risk and provision of amenity and ecological benefits. Amenity and environmental benefits arise through provision of a full-sized football pitch in Christchurch Playing Fields and the improvement of Christchurch ditch. 4.7 Option 6 Flood defences between Waterman Place and Reading Bridge This option consists of approximately 866 metres of flood defences extending from Waterman Place in the west to Reading Bridge in the east. The defences consist primarily of flood walls (approximately 810m) raised 310 – 1440mm above the existing ground. The remaining length consists of flood embankment (approximately 40m) and a short (10m) section of demountable defence of height 0.46mm and 0.83mm respectively. The defence will run broadly west to east along the southern bank of the River Thames. A short section of flood wall will replace the existing wall of the River Spice restaurant on Waterman Place, an embankment will then run through the Peter Brett Associates garden adjacent to Waterman Place. Following this a flood wall will run at property and road boundaries along the full extent of the Thames Path from Waterman Place to Clearwater Court (Thames Water office). At Thames Avenue it is proposed that the flood wall will run along the boundary of the private car park. A removable stoplog solution will run between Clearwater Court and Reading Bridge. Along the length flood walls will replace existing boundary walls. The existing walls being replaced generally consist of brick walls retaining raised private gardens and patios. It is assumed that the foundations of these walls are not adequate to support a new flood wall. The existing walls generally support a length of painted steel handrailing and/or hedgerows at the boundary edge. The existing appearance of these walls will need to be replicated where possible as part of the scheme. 45

The alignment of the defence and gradient of side slopes will vary to account for local features and to create a visually acceptable asset. Raised embankments will primarily consist of a clay core and fill material forming the shoulders. The flood walls will primarily involve construction of a new concrete core wall, clad to best match existing features. Flood gates and stoplogs will be provided at key access points (particularly at River Spice Restaurant, Caversham Wharf, Thames Side, Thames Avenue, De Montfort Road, Lynmouth Road and Clearwater Court) to facilitate day to day access. In addition, the pedestrian footpath adjacent to Norman Place will be raised to maintain access to the Thames Path. The outline design drawings can be seen in Appendix B. Health and Safety The solution will greatly reduce the risk to people from deep, fast flowing flood water out of bank, in all major residential areas within the ward of Abbey. A risk to people from deep fast flowing flood water in bank and out of bank on the Thames Path will remain, however this cannot be reasonably mitigated. There are several flood gates and stoplog sections in the scheme. Closing these gates and open sections could be hazardous for the operators if there is flood water present at these locations while they are closing them. To mitigate this, any openings will be closed at the initiation of a flood warning, this will provide sufficient time for all gates to be closed and stoplogs placed, before flood waters arrive. All embankments included in the scheme have been designed with a 2-metre-wide crest to minimise the risk of pedestrians walking along the embankment, be it recreationally or inspection related, falling down the slopes. In addition, these slopes have a gradient of 1 in 4 (≈14⁰) which is appropriate for normal maintenance methods using ride on machines16. Anti-social behaviour is a known issue throughout central Reading and Lower Caversham. There is a risk of creating spaces or features that encourage anti-social behaviour due to a lack of visibility, such as higher walls along the Thames Path on the south bank. A Service diversion may be required for a major underground 33kV electricity line, which passes below the defence alignment at the SSE Depot car park. Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option aligns with the strategy to reduce flood risk to people through delivery of flood risk management schemes. It meets the following objectives from the FRMP: • Reduce the risk of flooding to communities where possible. • Raise community awareness and understanding of all sources of flooding. Technical - Reduction in Flood Risk This option will affect a reduction in flood risk to a 0.5% AEP including the effects of climate change (35% increase in flows). Implementation of this option will move 90 properties to a lower flood risk band (Outcome Measure 2 (OM2)). 11 properties will be moved from the very significant and significant flood risk bands to the moderate and low flood risk band (Outcome Measure 2B (OM2B)). Table 4-5 - Summary of remaining properties at risk for Option 6 – Flood defences between Waterman Place and Reading Bridge (at end of appraisal period)

16 http://www.hse.gov.uk/aboutus/meetings/iacs/aiac/apg/280710/3-3-1-managing-slopes-and-banks.pdf 46

Technical – Sustainability This option is sustainable with appropriate maintenance of the stoplog gaps, flood gates, flood walls and embankments. As a solution, it takes advantage of passive solutions wherever possible, which aids its sustainability. Flood gates will be used where possible to avoid the possibility of stoplogs being lost and therefore unavailable for protection. Technical - Adaptive Approach for Flood Defence This would be a new flood defence. There are no existing flood defences suitable for adaption in Reading. Allowance has been made for future predicted climate change increases up to the end of the appraisal period. At present the option is designed to provide a SoP of 0.5% AEP including climate change. Opportunities have been identified to stagger the investment and enable future raising without major capital works, (i.e. overdesigned foundations) this will be investigated further at detailed design and implemented where appropriate. Technical – Buildability For the overall delivery programme, it is suggested the project be split into sections, which will be constructed consecutively in their entirety before proceeding to the next work area. This will minimise disruption on the local highway network, due to the import of materials to site. Completion of the scheme could be expedited by working on several fronts however, this will significantly increase the impact on the local community. To enable construction of the western flood walls and embankment between Waterman Place and Thames Avenue, access from Waterman Place and Thames Avenue will be required. For the flood walls between Thames avenue and Lynmouth Road construction access will be via Thames Avenue and Lynmouth Road. Lynmouth Road will also serve as an access point for construction of the flood wall between Lynmouth Road and Clearwater Court, in addition to access through the Thames Water car park. In each sequence, the Thames Path between the two active access points will be closed for the duration of the construction, an alternative pedestrian route will be implemented. Access to the Christchurch Bridge will be maintained at all times. Local roads will be used to bring materials to satellite access points, using 8-wheel road tippers, concrete wagons and flat-bed trucks. These material deliveries will be supervised by Traffic Marshals to help prevent the need for road closures. Opportunities exist to use the ends of side roads for welfare and materials laydown. From the access points, 1 tonne rubber tracked dumpers and small telehandlers, will be used to distribute materials to the work front. However, due to significant access restrictions along the Thames Path, lower outputs are expected, due to small plant being required to manoeuvre these areas. Ground protection measures are unlikely to be necessary due to the size of plant being used off the public highway.

Groundwater seepage may be an issue due to the granular layers underlaying the site. Significant amounts of ground water will have an impact on the programme of works, to allow for dewatering of excavations. There are known to be underground services in the central section of the alignment, particularly in the vicinity of the SSE depot, it will be important to avoid clashes with these key services. Environmental – Habitat Regulations Assessment and Ecology Option 6 is composed primarily of flood walls running along the Thames Path, from Waterman Place to Reading Bridge. A large portion of the defence alignment will involve replacing existing boundary walls, construction of this option will therefore require minimal vegetation clearance. A preliminary ground level bat roost assessment was undertaken to determine the likely presence of bat roosts. No trees of high potential or confirmed roosts were identified in this area. As bats are known to use the area for foraging and community, best practice construction mitigation should be employed during construction, such as a strategy for sensitive directional lighting. Further information is provided in the PEIR. Environmental – Historic Environment Opportunities/Impact No impacts to heritage features on the south bank are likely to occur. Construction machinery, noise, dust and vibration could affect the settings of some designated assets in close proximity to the scheme, however, these are predominantly located on the north bank. Further information is provided in the PEIR. Environmental - WFD Opportunities/Impact A Preliminary WFD Assessment has been undertaken for this option. Key components of Option 6 include linear defences. Potential impacts to WFD elements are likely to be minimal; the proposed flood wall will largely replace existing boundary walls or be constructed immediately adjacent. There is a low likelihood of temporary and localised impacts to terrestrial and aquatic species during construction. Although the proposed flood walls are in closer proximity to the River Thames compared to the north bank, Option 6 would have a comparatively minimal impact on WFD elements as the Reading Bridge Bypass is not a component of this option. It is considered that this option will not impact on Habitats Directive, UWWT Directive and Nitrates Directive. Further information is provided in the PEIR. Environmental - Geotechnical and Geo-environmental Risk Made Ground is present throughout the Caversham site, primarily within the topsoil layer (typically 200 – 300mm), but often extending to >800mm. Geo-environmental issues may be associated with handling and disposing of Made Ground. The area between Wolsey Road and Christchurch Playing Fields is a former industrial site. The presence and extent of contamination is identified within the GI interpretive report. Traces of asbestos were identified in the GI at Hill’s Meadow. Evidence of trash was also identified, including glass bottles and jars, metal bars and engine pistons. Further assessment will be required to understand the presence of asbestos throughout Hill’s Meadow. Stripping and excavating into the existing embankments creates a risk of contamination through handling and disposal. Borrow material for embankments will need to be sourced offsite; sufficient, suitable material is unlikely to be won onsite. Further information is provided in the PEIR.

Environmental - Land Take and Land Use Change No permanent impacts to land use will occur. Moorings alongside the Thames Path may need to be closed temporarily during construction, resulting in revenue losses. Commercial properties, particularly on Fry’s Island, Piper’s Island and along the southern Thames Path, may be temporarily impacted by construction works and potential access disruption. Liaison with RBC, businesses and residences along the south bank will be critical to this option. Further information is provided in the PEIR. Environmental - Landscape and Visual Amenity The Thames Path will remain a linear path with recreational purpose, providing interaction with the water. As such, its principal characteristics will be unchanged. However, Option 6 presents a risk to the integrity of the individual architectural styles of the properties that line the path. Additionally, the individual properties have been designed to maintain an open and green setting to the Thames, and this may be lost where the proposed wall replaces low walls and railings. There is an additional risk of indirect impact where the proposed wall reduces visibility and in turn leads to an increase in anti-social behaviour, reducing the value of the path as a recreational route. Further information is provided in the PEIR. Environmental - Recreation and Amenity Construction of this option would temporarily impact recreational use of amenity areas due to works and access requirements. Temporary disruption and disturbance is envisaged to the Thames Path along the south bank between Caversham Bridge and Reading Bridge. Temporary traffic management measures and successive pedestrian diversions would be required to reduce impacts to the public. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option would provide economic benefit of £66,566,176 at a benefit cost ratio of 11.0, with an incremental benefit cost ratio of 2.1 compared to Do Minimum. This option would provide a standard of protection against a flood event with a 0.5% AEP including the effects of climate change and move 90 properties to a lower flood risk band. The current raw Partnership Funding score (without contributions) is 56%. Contributions of £2,949,561 are required to achieve an adjusted Partnership Funding score of 100%. Economic - Whole-Life Costs Present value whole-life costs are £6,070,233 including maintenance costs. Carbon modelling was not carried out for this option. Political Drivers and Stakeholder Ambitions This option meets stakeholder ambitions. This is through reduced flood risk and provision of amenity and ecological benefits. Amenity and environmental benefits arise through provision of a full-sized football pitch in Christchurch Playing Fields and the improvement of Christchurch ditch.

4.8 Option 7 Flood defences between Promenade Road and Nire Road and between Waterman Place and Reading Bridge This option is a combination of Option 5 and Option 6 and consists of approximately 4,600 metres of flood defences extending from Promenade Road to Nire Road on the north bank of the River Thames and Waterman Place to Reading Bridge on the south bank. The majority of these defences will consist of embankments (approximately 1,930m) and flood walls (approximately 2,290m) raised 310 – 1,700mm above the existing ground to provide a SoP of 0.5% AEP. The remaining length (approximately 376m) is composed of temporary demountable defences located to the north and west of Christchurch Playing Fields and adjacent to Reading Bridge which will be 580mm and 830mm high respectively. In addition, a 200-metre-long bypass channel under Reading Bridge is required to mitigate increased flood risk to properties outside the benefit area. Compensatory storage was considered but found to be technically ineffective due to the lack of appropriate land which is hydraulically-linked to the floodplain lost. The defence on the Northern bank of the River Thames will run broadly west to east. Two short sections of flood wall and raised landscaped garden will run from the west of Abbotsmead Place car park to Promenade Road. Following this a flood wall will run adjacent to Promenade Road along the northern boundary of Christchurch Meadows, approximately adjacent to Cardinal Close the wall will transition into an embankment which will run through Christchurch Meadows until it reaches Elliots Way, a flood wall will then continue along the northern boundary until the boundary of Christchurch Playing Fields. The provision of the embankment between Cardinal Close and Elliots Way is (operating in conjunction with a sluice gate or similar) to isolate a section of Christchurch Ditch form the floodplain. At this location, surface water outfalls discharge into Christchurch Ditch, and this design will enable a strategic location for temporary pumping to both assist in gravity discharge of the surface water network and mitigate the impact of any residual seepage beneath the embankment and adjoining defences. A similar principle is being considered at other locations at the scheme including near Heron Island, to the northeast of Deans Farm Conservation Area, and at Berry Brook. Temporary demountable flood defences will then run along the western edge of Christchurch Playing Fields on a raised footpath, these temporary defences will continue east along Gosbrook Road to the boundary of Christchurch Playing Fields. Following this, an embankment will run along the eastern boundary of Christchurch Playing Fields and through Hill’s Meadows, with a short section of flood wall along the western side of George Street between these two embankments. A flood wall will replace existing walls from Hill’s Meadows along the southern edge of properties on Mill Green to The Causeway, an embankment will pass through the open area south of Paddock Road to Amersham Road Recreation Ground and flood wall will around the roadside boundary of Amersham Road Recreation Ground and south of properties on Honey Meadow Close. Another embankment will then run to the east of Nire Road to Ruskin Close, where a flood wall will tie into high ground. The defence on the Southern bank of the River Thames will also run broadly west to east along the southern bank of the River Thames. A short section of flood wall will replace the existing wall of the River Spice restaurant on Waterman Place, an embankment will then run through the Peter Brett Associates garden adjacent to Waterman Place. Following this a flood wall will run at property and road boundaries along the full extent of the Thames Path from Waterman Place to Clearwater Court (Thames Water office). At Thames Avenue it is proposed that the flood wall will run along the boundary of the private car park. A removable stoplog solution will run between Clearwater Court and Reading Bridge. Along the length flood walls will replace existing boundary walls. The alignment of the defence and gradient of side slopes will vary to account for local features and to create a visually acceptable asset. Raised embankments will primarily consist of a clay core and fill 50 material forming the shoulders. Where possible, the embankment in Hill’s Meadow will make use of existing raised, made ground. The flood walls will primarily involve construction of a new concrete core wall, clad to best match existing features. Flood gates and stoplogs will be provided at key access points (particularly at the University boat club, Wolsey Road, Heron’s Island, Mill Green properties, Mill Green boatyard, Amersham Road Recreation Ground, River Spice Restaurant, Caversham Wharf, Thames Side, Thames Avenue, DeMontfort Road, Lynmouth Road and Clearwater Court) to facilitate day to day access. In addition, flow control structures (non-return valve and a vertical sluice) will be provided where the defence crosses Christchurch Ditch to prevent bypass flooding. A road ramp will need to be provided immediately to the east of the road junction between Mill Road and Mill Green to facilitate access to Heron’s Island properties (which are not protected by the defence due to raised threshold levels) and the pedestrian footpath adjacent to Norman Place will be raised to maintain access to the Thames Path. The embankment will be maintained from the toe to allow a narrower crest and reduce the overall footprint, and it will include a key trench into existing ground to reduce the amount of seepage post- construction. Maintenance will consist primarily of grass cutting and will be undertaken as part of the wider maintenance of the public open space for efficiency. The outline design drawings can be seen in Appendix B. Health and Safety The solution will greatly reduce the risk to people from deep, fast flowing flood water out of bank, in all major residential areas within Reading and Caversham. A risk to people from deep fast flowing flood water in bank and out of bank in Christchurch Meadows and Amersham Road Recreation Ground will remain, however this cannot be reasonably mitigated. There are several flood gates and stoplog sections in the scheme. Closing these gates and open sections could be hazardous for the operators if there is flood water present at these locations while they are closing them. To mitigate this, any openings will be closed at the initiation of a flood warning, this will provide sufficient time for all gates to be closed and stoplogs placed, before flood waters arrive. All embankments included in the scheme have been designed with a 2-meter-wide crest to minimise the risk of pedestrians walking along the embankment, be it recreationally or inspection related, falling down the slopes. In addition, these slopes have a gradient of 1 in 4 (≈14⁰) which is appropriate for normal maintenance methods using ride on machines17. The sluice at Mill Green, where Christchurch ditch outfalls into the Thames, will required safe access for inspection and maintenance. This will be provided by pouring a set of concrete steps with a handrail, down to a concrete platform in channel, immediately downstream of the sluice. This will allow the sluice to be cleared safely if required. A Service diversion may be required for a major underground 33kV electricity line, which passes close to the defence alignment in Caversham Meadows and again north of the SSE depot car park. Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option aligns with the strategy to reduce flood risk to people through delivery of flood risk management schemes. It meets the following objectives from the FRMP: • Reduce the risk of flooding to communities where possible. • Raise community awareness and understanding of all sources of flooding.

17 http://www.hse.gov.uk/aboutus/meetings/iacs/aiac/apg/280710/3-3-1-managing-slopes-and-banks.pdf 51

• Enhance recreation and general amenity across the river basin. • Protect and enhance biodiversity through flood risk management schemes. Technical - Reduction in Flood Risk This option will affect a reduction in flood risk to a 0.5% AEP including the effects of climate change (35% increase in flows). Implementation of this option will move 739 properties to a lower flood risk band (Outcome Measure 2 (OM2)). 279 properties will be moved from the very significant and significant flood risk bands to the moderate and low flood risk band (Outcome Measure 2B (OM2B)). Table 4-4 - Summary of remaining properties at risk for Option 6 – Flood defences between Promenade Road and Nire Road (at end of appraisal period)

Moderate Risk Very Significant (Between 0.5% and Significant Risk Risk (5% AEP or 1.33% AEP chance of (Between 1.33% and 5% greater chance of flooding in any given AEP chance of flooding in flooding in any given year) any given year) year) 20% Most Deprived Areas 0 0 0 21-40% Most Deprived Areas 0 0 0 60% Least Deprived Areas 0 0 0

Technical – Sustainability This option is sustainable with appropriate maintenance of the stoplog gaps, flood gates, flood walls and embankments. As a solution, it takes advantage of passive solutions wherever possible, which aids its sustainability. Flood gates will be used where possible to avoid the possibility of stoplogs being lost and therefore unavailable for protection. Technical - Adaptive Approach for Flood Defence This would be a new flood defence. There are no existing flood defences suitable for adaption in Caversham. Allowance has been made for future predicted climate change increases up to the end of the appraisal period. At present the option is designed to provide a SoP of 0.5% AEP including climate change. Opportunities have been identified to stagger the investment and enable future raising without major capital works, (i.e. overdesigned foundations) this will be investigated further at detailed design and implemented where appropriate. Technical – Buildability For the overall delivery programme, it is suggested the project be split into sections, which will be constructed consecutively in their entirety before proceeding to the next work area. This will minimise disruption on the local highway network, due to the import of materials to site. Completion of the scheme could be expedited by working on several fronts however, this will significantly increase the impact on the local community. Localised access to construct the wall and bund adjacent to the College Car Park (Iceland Building) will be via Iceland’s drive-way and Abbotsmead. For defences along Promenade Road and within Christchurch Meadows access will be established at Promenade Road and Wolsey Road. A haul road will be established for the length of the clad reinforced concrete wall, to distribute all materials to the work front. To enable construction of the defences around Christchurch Playing Fields, access will be established from the North-West corner of Christchurch playing field on Gosbrook Road. Construction access to

Reading Bridge bypass channel will be via the north-west corner of Christchurch Playing Fields and Hills Meadow car park. Significant vegetation clearance, including mature trees is required in eastern Christchurch Meadows to enable construction of the bypass channel. Ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. To construct the bypass channel beneath George Street a full closure of George Street will be required. The estimated duration of construction at this location is not expected to exceed 2 weeks, clear diversion routes will be in operation, to minimise disruption. Hills Meadow will be accessed from the car park adjacent to George Street and from the end of Mill Road. Access to the rear of the buildings at Mill Green will be achieved from Mill Green in the West and the boat yard to the East, here access will be limited to small plant due to a constrained footpath. Residents access to the rear of these properties will also be removed for the duration of the works. For the embankments in the Amersham Recreation Ground area, access will be established from The Causeway, Meadow Way and Amersham Road. Amersham Road will also serve as an access point for the Honey Meadow Close wall. A protective matting haul road will run along the length of the Amersham Recreation Ground and Honey Meadow Close defences, to allow the distribution of materials from the access points to the work front. Significant vegetation clearance is required through the Honey Meadow Close area, ecological restraints will need to be adhered to, where possible this will be carried out as an early works package to suit these constraints and the wider programme. Access to the Nire Road Embankment area will be via the Northern extent of Nire Road, with a protective matting haul road extended to the Northern and Southern extents of the Nire Road embankment for material delivery by dumper. Access via Ruskin will be necessary to construct the wall in this location and marshals used to manage access to properties. To enable construction of the western flood walls and embankment between Waterman Place and Thames Avenue, access from Waterman Place and Thames Avenue will be required. For the flood walls between Thames avenue and Lynmouth Road construction access will be via Thames Avenue and Lynmouth Road. Lynmouth Road will also serve as an access point for construction of the flood wall between Lynmouth Road and Clearwater Court, in addition to access through the Thames Water car park. In each sequence, the Thames Path between the two active access points will be closed for the duration of the construction, an alternative pedestrian route will be implemented. Access to the Christchurch Bridge will be maintained at all times. Local roads will be used to bring materials to satellite access points, using 8-wheel road tippers and flat-bed trucks. These material deliveries will be supervised by Traffic Marshals to help prevent the need for road closures. On the north bank hard standings of approximately 10x10m will be installed inside the access points and site dumpers up to 9 tonnes in size and running on protective matting, will be used to distribute materials from the access points to the work front. This will help prevent the contamination of local roadways. On the South Bank opportunities exist to use the ends of side roads for welfare and materials laydown. From the access points, 1 tonne rubber tracked dumpers and small telehandlers, will be used to distribute materials to the work front. However, due to significant access restrictions along the Thames Path, lower outputs are expected, due to small plant being required to manoeuvre these areas. Ground protection measures are unlikely to be necessary due to the size of plant being used off the public highway. Groundwater seepage may be an issue due to the granular layers underlaying the site. Significant amounts of ground water will have an impact on the programme of works, to allow for dewatering of excavations. There are known to be underground services along the western end of the alignment in Christchurch Meadows and in the vicinity of the SSE depot, it will be important to avoid clashes with these key services.

Environmental – Habitat Regulations Assessment and Ecology Option 5 is a combination of Options 5 and 6, resulting in flood embankments and walls running from Promenade Road in the west to Nire Road in the west, a bypass under Reading Bridge, and defences along the south bank. Construction of this option will therefore require more vegetation clearance than Options 5 or 6 alone. Further information is provided in the PEIR. Environmental – Historic Environment Opportunities/Impact Option 7 is a combination of Options 5 and 6. All relevant historic environment impacts are covered in Sections 4.4.8, 4.5.8 and 4.7.8. Further information is provided in the PEIR. Environmental - WFD Opportunities/Impact Option 7 is a combination of Options 5 and 6. All relevant WFD impacts/opportunities are covered in Sections 4.4.9, 4.5.9 and 4.7.9. Further information is provided in the PEIR. Environmental - Geotechnical and Geo-environmental Risk Option 7 is a combination of Options 5 and 6. All relevant WFD impacts/opportunities are covered in Sections 4.4.10, 4.5.10 and 4.7.10. Further information is provided in the PEIR. Environmental - Land Take and Land Use Change Option 7 is a combination of Options 5 and 6. All relevant land take and land use change impacts are covered in Sections 4.4.11, 4.5.11 and 4.7.11. Further information is provided in the PEIR. Environmental - Landscape and Visual Amenity Option 7 is a combination of Options 5 and 6. All relevant land take and land use change impacts are covered in Sections 4.4.12, 4.5.12 and 4.7.12. Most landscape impacts for Options 3, 4 and 6 are localised and are unlikely to be compounded by the combination of different options. However, there is a risk that the reduction of the ‘green’ setting to the Thames, due to the new flood wall along the southern bank, could combine with the new concrete elements of the bypass to noticeably increase the presence of hard materials along this part of the Thames Corridor. This would be incongruous to the dominance of green elements along the Thames. Further information is provided in the PEIR. Environmental - Recreation and Amenity Option 7 is a combination of Options 5 and 6. All relevant recreation and amenity impacts are covered in Sections 4.4.13, 4.5.13 and 4.7.13. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option would provide economic benefit of £137,891,075 at a benefit cost ratio of 5.9, with an incremental benefit cost ratio of 3.6 compared to Do Minimum. This option would provide a standard of protection against a flood event with a 0.5% AEP including the effects of climate change and move 739 properties to a lower flood risk band.

The current raw Partnership Funding score (without contributions) is 34%. Contributions of £16,878,712 are required to achieve an adjusted Partnership Funding score of 100%. Economic - Whole-Life Costs Present value whole-life costs are £23,190,329 including maintenance costs. Carbon modelling was not carried out for this option. Political Drivers and Stakeholder Ambitions This option meets stakeholder ambitions. This is through reduced flood risk and provision of amenity and ecological benefits. Amenity and environmental benefits arise through provision of a full-sized football pitch in Christchurch Playing Fields and the improvement of Christchurch ditch.

4.9 Option 8: Reading Bridge Bypass This option consists of approximately 200m of bypass channel extending from Christchurch Meadows in the west, to the River Thames upstream of the Caversham Weir complex, in the east. The bypass channel is designed to be permanently wet to create a landscape feature. The bypass channel will run in a broadly west to east direction, beneath George Street on the approach to Reading Bridge, and through the northern section of Hill’s Meadow car park. The bypass channel will pass beneath George Street in open channel and then outlet into the River Thames. RBC have expressed concern over the permanent loss of car park area as a consequence of this option, however the benefits of the open channel are considered to outweigh those associated with the culverted option. This is primarily due to public safety, cost, environmental impact and missed environmental opportunities. These are discussed further in Sections 4.9.1 to 4.9.16. The outline design drawings can be seen in Appendix B. Health and Safety The open channel option is far better from a health and safety aspect as there is very limited danger posed by an open channel. However, suitable edge protection may be required to protect people and vehicles from entering the channel during flood events, where the water may be deep and fast flowing. A culvert underneath the road and the car park was ruled out as it would require a large opening to allow the conveyance of sufficient flood water. A gated culvert would likely attract unwanted attention from people wishing to enter the culvert, who would be at great threat if they became stuck in the culvert during a flood event. As a result, a heavy-duty security screen would need to be placed over both openings to prevent access. These screens would need to be very secure and be checked regularly, as the risks to someone being able to get past the screen and then not get out of the culvert, could result in loss of life. The use of life rings, signage and safe egress routes on either side of the channel will further reduce the risk to human health in high flow events. Strategic - Aligned with Thames River Basin Flood Risk Management Strategy and Project Objectives This option does not align with the strategy to reduce flood risk to people through delivery of flood risk management schemes. The option reduces the flood risk of properties to the west of the George Street Bridge by enabling increased downstream flow. However, this does not benefit properties to the east (between Christchurch Playing Fields and Nire Road) which are at greater flood risk. Technical - Reduction in Flood Risk This option was discounted before technical modelling was carried out.

Technical – Sustainability This option is sustainable with appropriate maintenance of the open channel or culvert, the passive features aid the sustainability of this option. It has been assumed that do minimum maintenance will persist for the 100-year appraisal period as the key asset here will be the culvert under George Street (B3345). It can be assumed that when this culvert deteriorates, it will cause the highway to deteriorate before it becomes a significant flood risk due to collapse. Therefore, highways maintenance will replace the culvert under road maintenance, lessening the capital intervention required within future maintenance costs. Technical - Adaptive Approach for Flood Defence There is little scope for an adaptive approach with this option. Technical – Buildability The solution is buildable; however, both the channel will pass below the B3345. This may result in extensive traffic disruption to one of the main vehicular crossing points over the Thames in Reading and so is likely to be met with opposition. The proximity of working alongside the B3345 also adds complexity. Environmental – Habitat Regulations Assessment and Ecology Option 8 would require excavation of an approximately 200m long bypass channel, with a varying width of 20 – 30m. The Reading Bridge Bypass would result in the loss of numerous poplars and elms along George Street and significant modification to the heavily modified River Thames. It could result in the potential loss of fish species during construction, and disturbance to habitat and substrate, including nursery, refuges and spawning areas. The poplar trees lining George Street on the north side of Reading Bridge were included in the ecological survey scope and have been confirmed to have low or negligible potential for bat roosts. There are additional areas which were not included in the previous survey scope. Additional Phase 1 Habitat, otter and preliminary bat tree surveys will be required for these areas. We will produce a Phase 1 Habitat Survey Addendum and update the otter and bat survey reports with the results. Further information is provided in the PEIR. Environmental – Historic Environment Opportunities/Impact Informal consultation with NEAS archaeologists has indicated that a cultural heritage desk-based assessment is unlikely to be required due to the low risk of archaeological features being encountered during works or heritage assets being affected by the scheme. However, further archaeological investigation is likely to be required for the Reading Bridge Bypass. Further GI in this area may need to be supervised by an archaeological watching brief. Further consultation with Berkshire Archaeology would be required for this option. Further information is provided in the PEIR. Environmental – WFD Opportunities/Impact A Preliminary WFD Assessment has been undertaken for this option. The Reading Bridge Bypass has the potential for significant impacts to natural substrate, river width variation, fish habitat (including refuge, nursery and spawning areas), and constrained, canalised flows. There is an opportunity to increase macrophyte and invertebrate species diversity post construction. A Detailed WFD Assessment would be required for the Reading Bridge Bypass. Further information is provided in the PEIR.

Environmental - Geotechnical and Geo-environmental Risk Traces of asbestos were identified in the GI at Hill’s Meadow. Evidence of trash was also identified, including glass bottles and jars, metal bars and engine pistons. Further assessment will be required to understand the presence of asbestos throughout this area. The Reading Bridge Bypass will require the excavation of Made Ground. Further GI will be required to determine the ground conditions and presence of contaminants in this area. Excavated material will need to be disposed of appropriately or beneficially reused elsewhere (if appropriate). Further information is provided in the PEIR. Environmental - Land Take and Land Use Change This option predominantly impacts the Hill’s Meadow surfaced car park, permanently removing approximately 0.1ha and an estimated 125 car parking spaces from use, and an existing playground in Christchurch Meadows which will need to be relocated. Smaller areas of land take within amenity grassland areas will also occur. Liaison with landowners of Christchurch Playing Fields, Hill’s Meadow and the car park is critical to this option. Further information is provided in the PEIR. Environmental - Landscape and Visual Amenity In principle, the proposed bypass channel will be consistent with the baseline characteristics of the Thames Corridor. It will create an additional channel with formalised banks and a large urbanised, yet ‘green’ island. Reinstated lawns, riverside paths and specimen trees will maintain consistency. However, despite the consistency, the bypass will result in the loss or disturbance of major characteristics, including the line of poplars and the elm avenue along George Street. Large concrete elements will be installed to create the culvert under George Street, and these elements risk becoming incongruous to the urban green environment. Further information is provided in the PEIR. Environmental - Recreation and Amenity Construction of this option would temporarily impact recreational use of amenity areas due to works and access requirements. Temporary disruption and disturbance is envisaged, particularly at Christchurch Playing Fields (including the playground and tennis courts), Hills Meadow, and PROWs along the river. Construction will temporarily disrupt current access routes to Christchurch Meadow, Hill’s Meadow, Hill’s Meadow car park and George Street, and some areas of the river front. Alternative access routes would be provided during construction. Public footpaths along the northern bank of the Thames will remain accessible via Reading Bridge. The bypass channel will result in the permanent loss of approximately 125 car parking spaces at Hills Meadow car park and will require the relocation of an existing playground to a suitable alternative location. Public footpaths would be provided across the bypass, ensuring this existing route is not permanently affected. Further information is provided in the PEIR. Economic - Economic Benefits Assessment This option was discounted as a standalone option before technical modelling was carried out, therefore, no economic assessments were completed.

Economic - Whole-Life Costs This option was discounted as a standalone option before technical modelling was carried out, therefore, no economic assessments were completed. Political Drivers and Stakeholder Ambitions This option does not meet stakeholder ambitions. Although the bypass channel reduces the flood risk to West Caversham, it does not result in any reduction in risk to the east, where the greatest flood risk currently exists. The open channel option will provide amenity and ecological benefits through remediation of ground contaminants and landscaping.

4.10 Cost Benefit Appraisal Summary Table Option PV Costs PV Benefits Average Incremental Option for Outcome Outcome Raw BCR BCR Incremental Measure 2 Measure 4 Partnership Outcome (compared to Calculation (OM2b) Funding Score Measure 1 do Minimum)

Option 1 £0 £0 N/A N/A - - - - (Do Nothing)

Option 2 £79,876 £54,177,102 678.3 N/A (Do Minimum)

Option 3 £ 3,858,423 £61,531,717 15.9 1.9 Do Minimum 43 (10) - 82% (£752,045) (Prom. Road to Playing Fields)

Option 4 £ 14,839,256 £114,936,193 7.7 4.1 Do Minimum 606 (258) - 45% (Playing Fields to (£9,043,400) Nire Road)

Option 5 £ 17,588,660 £122,000,297 6.9 3.9 Do Minimum 649 (268) - 40% (Prom. Road to Nire (£11,610,913) Road)

Option 6 £ 6,070,233 £66,556,176 11.0 2.1 Do Minimum 90 (11) - 56% (Waterman Place to (£2,949,561) Reading Bridge)

Option 7 £ 23,190,329 £137,891,075 5.9 3.6 Do Minimum 739 (279) - 34% (Prom. Road to Nire (£16,878,712) Road & Waterman Place to Reading Bridge)

Following the various stages (1 to 6) of the FCERM-AG decision rule (Figure 4-10), the following decision process is undertaken to identify the preferred option: Option 3 has the highest BCR of the “Do Something” options, followed by Option 6, however most of the benefits associated with these two options can be attributed with the Do Minimum option. Therefore, they have a relatively low Incremental Benefit Cost Ratio (iBCR) compared to Do Minimum, at 1.9 and 2.1 respectively, indicating limited justification in the additional investment. It is noted this is below the required IBCR of 3.0 required to justify a standard of protection against a flood event with a 0.5% AEP (see Figure 1). Options 4, 5, and 7 each have an IBCR of greater than 3.5 compared to Do Minimum – ranging between 3.6 and 4.1. Of these options, Option 4 has the highest BCR at 7.7. Option 7 has the lowest BCR of these three options at 5.9, and the lowest IBCR at 3.6. However, Option 7 does offer the greatest number of OM2 properties in comparison to the options. It should also be noted that the IBCR of Option 5 (compared to option 4) is 2.6, and in turn the IBCR of Option 7 (compared to option 5) is 2.9. None of the options have a raw partnership funding score in excess of 100%, and so require external contributions or project savings to be made. At this stage, the Reading and Caversham Flood Alleviation Scheme has received an allocation of £5,000,000 within the current levy programme. Agreement of this allocation was given in the Thames Regional Flood and Coastal Committee meeting on 11 October 2017. 59

In addition, both Reading Borough Council (as a landowner affected by the scheme), and an independent private landowner (also affected by the scheme) have expressed an interest in financial contributions towards the project cost. A partnership funding assessment has been undertaken to review additional potential sources of funding. This assessment identified four potential funding partners – specifically Reading Borough Council, Thames Regional Flood and Coastal Committee (additional contribution), Thames Valley Berkshire Local Enterprise Partnership, and SSE Networks. In addition, it is envisaged that Reading Borough Council and local environmental groups (voluntary) will pick up various elements of the maintenance regime as part of their existing practices. Given the robust BCR and IBCR, coupled with it delivering the highest outcome measures and having the greatest potential to attract partnership funding. Option 7 has been identified as the leading option in accordance with Stage 6 of the process set out in FCERM-AG (Figure 4-10). Options 4 and 5 remain as viable alternatives if the required partnership funding to deliver Option 7 cannot be secured as part of the project. The reasoning above justifies the selection of Option 7 - Promenade Road to Nire Road & Waterman Place to Reading Bridge (0.5% AEP) as the leading option. This option secures 739 Outcome Measure 2, 279 Outcome Measure 2b and in excess of £137million in present value benefits (Outcome Measure 1).

4.11 Project Costs Costs have been informed by early supplier engagement from an Environment Agency Water and Environment Management (WEM) Framework Lot 4 contractor, Jackson Hyder. Other project costs have been informed by reference to previous similar schemes and anticipated works required. Details of project costs are provided in Appendix H.

4.12 Appraisal Summary Table of Short List Options Option Description Overall Key Technical Points / Constraints Key Environmental Impacts Env Key Economic Impacts Econ Key Social Impacts Social PV Costs BCR Key Risks Rank Rank Rank Rank 1 Do Nothing 8th N/A Increase in risk of environmental incident 8th Increase in Flood Risk 8th Negative impact on 8th £0 N/A N/A through non-maintenance of the channel wellbeing due to increased and assets. flood risk. Degradation of assets due to lack of maintenance. Known water quality issues in Christchurch Ditch could also be exacerbated. Quality of surrounding public land may deteriorate due to a lack of maintenance. Increased sedimentation risk through ceasing maintenance works (e.g. on Christchurch Ditch) and an increasing flood risk over time. Carbon – 0 Tonnes 2 Do Minimum 6th Existing fly-tipping issue with The risk of ecological impacts may 6th Increase in Flood Risk over 6th Improved social benefits as 7th £79,876 678.3 N/A Christchurch Ditch, causing potential increase over time as flood risk increases time due to climate change. a result of being at lower blockage. with climate change and existing flood flood risk. ~£15 per person Present Value Benefits - prevention assets become inadequate. per year £54,177,102 Low, albeit increasing (climate change & asset deterioration), risk of impacts to historic assets. Increased flood risk may affect the accessibility and quality of recreational and public land Insignificant changes to WFD opportunities / impacts, geotechnical / geoenvironmental risk, landscape & visual amenity. Carbon – Not Modelled 3 Flood defences 4th Option requires large embankments and Removal of a number of mature trees 1st Improves standard of 4th Improved social benefits 5th £ 3,858,423 15.9 Traffic issues in Reading (Promenade flood walls which could result in will be required, along with some protection to a flood event as a result of being at town centre affects Road to significant volumes of engineering fill isolated, young trees. with a 0.5% AEP including lower flood risk. ~£282 per deliveries, outputs and Christchurch and construction material being brought the effects of climate person per year. programme Significant opportunities for Playing Fields) to site using the local road change. environmental enhancement around Opportunity to increase Outline design does not infrastructure. 0.5% AEP Christchurch Ditch. Present Value benefits - amenity value with include for seepage path (including PROW in Christchurch meadows may £61,531,717 improvement of cut-off Borrow material will need to be won climate change) need to be diverted for the duration of Caversham Ditch. offsite for a short section of Issues with landowners works. embankment. private road access, Significant underground services are construction compound Temporary land use and recreational known to underlay the site. access impacts during construction. Constraints to site, Temporary, infrequent land use impacts access and working during flood events when Christchurch areas imposed with planning consent

Option Description Overall Key Technical Points / Constraints Key Environmental Impacts Env Key Economic Impacts Econ Key Social Impacts Social PV Costs BCR Key Risks Rank Rank Rank Rank Meadows is inundated and used for Environmental flood storage. constraints Embankments and walls will introduce Disrupting a major new elements to the landscape. In some underground service areas, such as through Christchurch line Meadows, this could be an enhancement. Key landscape risk associated with loss of mature trees, affecting views. Embankment may introduce privacy/security issues to residences adjacent to Christchurch Meadows. Unlikely to impact on Habitats, UWWT or Nitrates Directive. Provided appropriate, sensitive construction mitigation measures are implemented, there is unlikely to be permanent changes to the status/potential of the water body. Carbon – 2,143 tonnes 4 Flood defences 2nd Option requires large embankments and Loss of notable poplars in Christchurch 3rd Improves standard of 1st Improved social benefits as 2nd £ 7.7 Contamination – (Christchurch flood walls which could result in Playing Fields and alongside George protection to a flood event a result of being at lower 14,839,256 particularly in the Playing Fields to significant volumes of engineering fill Street, as well as the loss of hedgerow with a 0.5% AEP including flood risk. ~£282 per bunded materials in Hills Nire Road) and construction material being brought and other mature trees, which are used the effects of climate person per year. Meadows to site using the local road by foraging and commuting bats. change. 0.5% AEP Opportunity to increase Construction beside busy infrastructure. Permanent clearance of an area of (including Present Value benefits - amenity value with roads woodland south of Honey Meadow climate change) PROW in Hill’s Meadow and Amersham £114,936,193 landscaping of Hills Close. Traffic issues in Reading Road Recreation Ground may need to be Meadows and the creation town centre affects diverted for the duration of works. Potential for ecological enhancement of a full-sized football pitch deliveries, outputs and and community benefit around Hill’s on Caversham Playing Works required to take place in programme Meadow. Fields to allow the club to immediate vicinity of the B3345. host sanctioned adult Outline design does not Potential impacts to reptiles and badger, Limited access down a narrow footpath amateur matches. include for seepage path although this is likely to be managed for wall alignment in Mill Green Area. cut-off through construction best practice and Large amount of tree and vegetation habitat compensation. Issues with landowners removal to allow construction of bypass private road access, Traces of asbestos have been identified channel and wall behind Honey Meadow construction compound at Hill’s Meadow, along with trash and Close properties. other sources of potential Constraints to site, contamination. Stripping and excavating access and working areas into the existing embankments creates a imposed with planning

risk of contamination through handling consent and disposal. Substantial borrow Environmental material will need to be won offsite for constraints embankments. Temporary land use and recreational access impacts during construction. Temporary, infrequent land use impacts during flood events when Christchurch Meadows is inundated and used for flood storage.

Option Description Overall Key Technical Points / Constraints Key Environmental Impacts Env Key Economic Impacts Econ Key Social Impacts Social PV Costs BCR Key Risks Rank Rank Rank Rank Embankments and walls will introduce new elements to the landscape. In some areas (e.g. west of Christchurch Playing Fields) this will be relatively minor or even ‘like for like’ (e.g. Hill’s Meadow). Risk of affecting symmetry present along George Street. Material choices for hard defences will be key to integrating with streetscape/landscape. Low risk of impact to Grade II listed building (Dean’s Farm Cottage) during construction (i.e. machinery use, noise and dust). Exclusion zones during construction are recommended. Replacement of three junior-sized football pitches with a single full-size field will benefit the local community. Permanent loss of car park spaces at Hills Meadow due to bypass channel. Bypass has potential for significant WFD impacts – natural substrate, river width variation, fish habitat (including refuge, nursery and spawning areas), and constrained, canalised flows. Opportunities to increase macrophyte and invertebrate species diversity post construction. Detailed WFD Assessment required. Carbon – 22,118 tonnes 5 Flood defences 1st Option requires large embankments and Combined Options 3 and 4. 4th Improves standard of 2nd Improved social benefits as 1st £ 6.9 Contamination – (Promenade flood walls which could result in protection to a flood event a result of being at lower 17,588,660 particularly in the Larger area affected by construction and Road to Nire significant volumes of engineering fill with a 0.5% AEP including flood risk. ~£282 per bunded materials in Hills clearance works. Longer construction Road) and construction material being brought the effects of climate person per year. Meadows duration. to site using the local road change. 0.5% AEP Opportunity to increase Disrupting a major infrastructure. Significant opportunities for (including Present Value benefits - amenity value with underground service line environmental enhancement along climate change) PROW in Christchurch meadows, Hill’s £ improvement of Christchurch Ditch and potentially Hill’s 122,000,297 Construction beside busy Meadow and Amersham Road Caversham Ditch, Meadow. roads Recreation Ground may need to be landscaping of Hills diverted for the duration of works. Carbon – 24,261 tonnes Meadows and the creation Traffic issues in Reading of a full-sized football pitch town centre affects Significant underground services are on Caversham Playing deliveries, outputs and known to underlay the site. Fields to allow the club to programme Works required to take place in host sanctioned adult Outline design does not immediate vicinity of the B3345. amateur matches. include for seepage path Limited access down a narrow footpath cut-off for wall alignment in Mill Green Area. Environmental Large amount of tree and vegetation constraints removal to allow construction of bypass

channel and wall behind Honey Meadow Close properties.

Option Description Overall Key Technical Points / Constraints Key Environmental Impacts Env Key Economic Impacts Econ Key Social Impacts Social PV Costs BCR Key Risks Rank Rank Rank Rank 6 Flood defences 5th Option requires the replacement of large Comparatively minimal impact on WFD 2nd Improves standard of 5th Improved social benefits as 4th £ 6,070,233 11.0 Disrupting a major (Waterman sections of existing boundary wall with elements as proposed flood wall will protection to a flood event a result of being at lower underground service line new concrete flood walls, which could largely replace existing boundary walls. with a 0.5% AEP including flood risk. ~£282 per Place to Traffic issues in Reading result in significant volumes of the effects of climate person per year. Reading Limited opportunities for environmental town centre affects construction material being brought to change. Bridge) enhancement along the Thames Path. Opportunity to increase deliveries, outputs and site using the local road infrastructure. Present Value benefits - amenity value with programme 0.5% AEP May exacerbate existing anti-social PROW along Thames Path will need to improvement of Thames (including behaviour issues. £66,556,176 Working beside a be diverted for the duration of works. Path. climate change) watercourse Unlikely to impact on Habitats, UWWT or Limited access down a narrow footpath Nitrates Directive. Provided appropriate, for much of the defence alignment. sensitive construction mitigation measures are implemented, there is unlikely to be permanent changes to the status/potential of the water body. Carbon – not modelled

7 Flood defences 3rd Option requires large embankments and Combined Options 5 and 6. 5th Improves standard of 3rd Improved social benefits as 3rd £ 5.9 Contamination – enade flood walls which could result in protection to a flood event a result of being at lower 23,190,329 particularly in the (Prom Larger area affected by construction and significant volumes of engineering fill with a 0.5% AEP including flood risk. ~£282 per bunded materials in Hills Road to Nire clearance works. Longer construction and construction material being brought the effects of climate person per year. Meadows Road & duration. to site using the local road change. Waterman Opportunity to increase Disrupting a major infrastructure. Carbon – not modelled Place to Present Value benefits - amenity value with underground service line PROW in Christchurch meadows, Hill’s improvement of Reading £137,891,075 Construction beside busy Meadow, Amersham Road Recreation Caversham Ditch, Bridge) roads Ground and the Thames Path may need improvement of Thames 0.5% AEP to be diverted for the duration of works. Path, landscaping of Hills Traffic issues in Reading (including Meadows and the creation town centre affects Significant underground services are climate change) of a full-sized football pitch deliveries, outputs and known to underlay the site. on Caversham Playing programme Works required to take place in Fields to allow the club to Outline design does not immediate vicinity of the B3345. host sanctioned adult include for seepage path amateur matches. Limited access down a narrow footpath cut-off for wall alignment in Mill Green Area Working beside a and for significant length of south bank watercourse defence alignment. Environmental Large amount of tree and vegetation constraints removal to allow construction of bypass channel and wall behind Honey Meadow Close properties. 8 Bypass channel 7th RBC preference is for a culvert, which is Excavation over an area of 207m by 20- 7th Improves standard of 7th Improved social benefits as 6th - - Issues with landowners at George Street significantly worse than an open channel 30m (i.e. 3900 – 5850m2) protection to a flood event a result of being at lower private road access, from an environmental and safety point with a 1% AEP including the flood risk. ~£279 per construction compound 1% AEP Removal of mature trees lining George of view. effects of climate change. person per year. (including Street and through Hill’s Meadow – high Constraints to site, climate change) Improves flood protection standard ecological and landscape impact. Opportunity to increase access and working areas upstream of bypass however, may the amenity value with imposed with planning Permanent adverse landscape impacts increase flows downstream. improvement of Hills consent associated with large box culvert under Meadows. Targets wrong area – few properties George Street. Environmental upstream of bypass at very significant constraints flood risk (8). Therefore, there are

Option Description Overall Key Technical Points / Constraints Key Environmental Impacts Env Key Economic Impacts Econ Key Social Impacts Social PV Costs BCR Key Risks Rank Rank Rank Rank limited benefits compared with the Potential for beneficial landscape Stakeholder Engagement relatively high cost. impacts associated with conversion of – Preference for culvert Hill’s Meadow carpark to flood channel.

Traces of asbestos found in Hill’s Meadow, along with other potential sources of contamination. Risks associated with exposing sources of contamination to people and waterbodies, handling and disposal of contaminated material. Permanent land use impact to Hill’s Meadow carpark and public space. Carbon – not modelled

4.13 Selection and Details of Preferred Option The six “Do Something” options assessed are: Option 3: Flood defences between Promenade Road and Christchurch Playing Fields, Option 4: Flood Defences between Christchurch Playing Fields and Nire Road, Option 5: a combination of Options 3 and 4, Option 6: Flood defences between Waterman Place and Reading Bridge, Option 7: a combination of Options 5 and 6, and Option 8: Bypass channel at George Street. Of the six “Do Something” options assessed, Option 3 has the greatest BCR at 15.9. However, this is due to the high benefits secured by the Do Minimum scenario and this being the lowest cost option. The iBCR in comparison to Do Minimum is the lowest of the Do Something options at 1.9. Option 4 (Defences from Christchurch Playing Fields to Nire Road) has the highest iBCR, compared to Do Minimum, at 4.1. The iBCR of Option 7 (Defences from Promenade Road to Nire Road and Waterman Place to Reading Bridge) compared to Do Minimum is 3.6. Option 7 also delivers the greatest value of OM1 benefits (at £137,891,075) and OM2 properties (at 739). Based on appraisal of options against the assessment criteria as detailed in section 4, detailed hydraulic modelling and economic assessment, Option 7 has been identified as the preferred option. This is based on the option delivering the project objectives in their entirety, including those of wider stakeholders, alongside the delivery of the greatest outcome measures available. This option has a benefit cost ratio of 5.9 and a raw Partnership Funding Score of 34%. If the required partnership funding and/or project savings of £16,878,712 cannot be achieved then the selection of Option 7 as the preferred option will be reviewed and either Option 4 or Option 5 will be progressed instead. .

Figure 4-10: FCERM-AG option decision tree

5 Conclusion & Recommendations

This options assessment has identified a likely preferred option which satisfies the four main categories of assessment (Technical, Environment, Economic and Social). The current raw Partnership Funding score (without contributions) for Option 7 is 34%. Contributions or savings of £16,878,712 are required to achieve an adjusted PF score of 100%. These costs contribute towards the Project Costs for Approval of £23,190,329 (including 50th percentile risk allowance). A contribution of £5,000,000 of Local Levy has already been allocated to the project from Thames Regional Flood and Coastal Committee (RFCC). Opportunities to achieve project cost savings will be identified during the detailed appraisal stage and additional economic benefits associated with road and infrastructure disruption will be assessed. The recommendation is to seek engagement with stakeholders on options and funding and undertake required surveys before taking the project forward to the full business case (FBC) stage.

Appendix A: Long list of Options (From Initial Assessment)

Project Name: Reading Caversham FAS Priority: Medium Assessors: Karn Shah, Laura Hutchings, CH2M Hill Environment Agency Reviewers: Brian Roberts, Melanie Ward (PSO) Usman Khan (APT) Jo Dodworth (NEAS)

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? Do nothing Do nothing Study area All operational and maintenance activities Yes Required to support development of business cease case and benefit cost ratios. Do minimum Do minimum Study area Continue with current operational and Yes Required to support development of business maintenance activities case and incremental b/c ratio. Do more Do more Study area Enhanced maintenance activities, No Maintenance and operation of weirs is including routine dredging, etc. currently carried out for navigation purposes. More maintenance not expected to reduce flood risk. Non-structural Improved flood Study area Enhanced flood warning to allow residents No Not funded via the capital programme. Flood (by EA) warning to prepare plus appropriate warnings already provided for Thames. Better implementation of flood action plans modelling would be required for an improvement to the flood warnings. However, it is believed that the current level of flood warning gives sufficient time for the deployment of defences, if required. Non-structural Flood action plans Study area Improved direction of reactionary flood No Although this option is not taken further at (by EA) defence measure (fire crews, temporary initial assessment as it is not funded via the pumps, etc.) capital programme, it is recommended that community members are actively involved in setting up Flood Action Plans. Amersham Road Community Group already exists, and could be involved in setting up a Flood Action Plan

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? Property level Property level Study area Protection to individual properties (e.g. via Yes Assumed to be viable for all ground floor protection protection air brick covers, door guards etc). residential properties in the very significant risk band. However, the depth and duration of flooding at these properties would have to be analysed at the next stage, as PLP is only suitable where flood depth is less than 500mm and duration less than 3 days. PLP could be offered as an option in combination with other options. Operational Improve Study area For example, appropriate control of flood No The only significant active assets that have an (by Others) operation/design flows from/through 3rd party sluices/weirs. influence on water levels during floods are the of assets not Caversham weirs. Better use of the Caversham owned by the EA Weirs (particularly the Last Hope Weir) is an option that is already on the 6-year plan, and so will not be taken forward for assessment here. Caversham Bridge and Reading Bridge do not appear to present a major control on flows. Planning Land re- Study area Re-designation / reuse of land in affected No No imminent major development. Existing designation areas - long-term (100yr). development is predominantly housing of good quality, and in many cases, significant history, so unlikely to be replaced over next 100 years. Land Attenuate flows in Upstream of Changes to farming practices or in certain No Whilst this practice should be encouraged, it is management rural area study area, on a parts of the catchment specific areas unlikely to have any significant benefit for (farmland use) catchment wide managed in specific ways. affected properties in Reading Caversham. The scale practice would have to be on a catchment wide scale to have an impact on the flood risk at Reading Caversham Land Attenuate flows in Study area Use of SUDS drainage on new No No significant new development pressure in management urban areas developments, make changes to urban Caversham. Given the large flows of the (SUDS) areas to reduce speed of runoff. Thames and flood volumes, this would not have

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? any impact on Thames flows, which is the main source of flooding here. Urban drainage Improve urban Study area Improved surface water drainage system. No There are areas within the defined study area drainage. that are susceptible to surface water flooding. However, given the large flows of the Thames and flood volumes, improving the surface water drainage system would not have any impact on Thames flows, which is the source of flooding here. Structural Earth bunds Study area – Mill Flood bund Yes Could potentially be used to protect clusters of Green, Hill properties on Mill Green. There could be scope Meadows to achieve this via a combination of walls, demountables and bunds, depending on existing structures. However, the need for compensatory storage could make this option unviable. Not considered for disperse properties as it would not be economically viable. Requires a cluster of properties and appropriate geography in order to be viable. Structural Flood walls Study area – Mill Flood walls Yes Could potentially be used to protect clusters of Green, Hill properties on Mill Green. There could be scope Meadows to achieve this via a combination of walls, demountables and bunds, depending on existing structures. However, the need for compensatory storage could make this option unviable. Not considered for disperse properties as it would not be economically viable. Requires a cluster of properties and appropriate geography in order to be viable. Structural Demountable Study area – Mill Temporary demountable defences Yes An alignment for demountable defences has Green, Hill been developed as part of the SCRR scheme, restricting flow through the culvert under

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? Meadows, George George Street, placing 1 set of defences on Street George Street and a longer defence along Mill Green. This option will be taken forward for assessment. Structural Conveyance Study area Channel deepening or widening No To reduce/remove inundation of the floodplain near Caversham/Reading due to the Thames, significant channel re-profiling/widening would be required. Additionally, weir works may be required. Such works would also have a high whole life cost associated with maintenance. Given the potential for benefits (low), this option is very unlikely to be economically viable. Also significant environmental dis- benefits. Likely to be funded by revenue, not GiA. Structural Conveyance Study area Supplementary bypass channel(s, tunnels Yes A bypass channel is possible through Hills or floodway Meadow, with a culvert under George Street. A channel is not required upstream of George Street, as it would have minimal impact on flood risk. This option could increase the risk of flooding downstream, however. Structural Conveyance Study area River restoration and/or pinch point Yes A bypass channel is possible through Hills improvements (bridges, culverts and Meadow, with a culvert under George Street. weirs) The culvert would alleviate pressure on the pinch point (George St). This option could increase the risk of flooding downstream, however. Better use of the Caversham Weirs (particularly the Last Hope Weir) is an option that is already on the 6-year plan, and so will not be taken forward for assessment here.

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? River restoration could be considered for smaller watercourses (Christchurch Ditch, Berry Brook) in a separate study – not to be taken forward for assessment here. Flood storage Online Upstream of Use of active structures and re-profiling to No Thames Floods in this area are typically of a area study area, on a store water online. long duration and involve large volumes of catchment wide water. This option is not technically and scale economically viable due to the size of FSA area required in order to deliver sufficient benefits. There is not sufficient space to create FSAs of this size in or near the study area, as the study area is already in the floodplain. Groundwater could also be an issue, as the storage areas would fill up with Flood storage Offline Upstream of Gravity or pumping to offline storage area No Thames Floods in this area are typically of a area study area, on a long duration and involve large volumes of catchment wide water. This option is not technically and scale economically viable due to the size of FSA area required (likely greater than several million m3) in order to deliver sufficient benefits. Flood storage Aquifer storage Upstream of Flood storage by pumping into permeable No Thames Floods in this area are typically of a study area, on a aquifer long duration and involve large volumes of catchment wide water. This option is not technically and scale economically viable due to the large volume of flow in the Thames during floods (>200m3/s). Floodplain Washlands Upstream of Enhance/increase natural floodplain No It may be possible to store small volumes of storage study area, on a attenuation with cascade of passive flood water in Christchurch Meadow and King’s catchment wide storage areas in existing floodplain Meadow, with the use of bunds. It may also be scale possible to make improvements to biodiversity Compensatory and WFD requirements through this option. storage – This option is expected to provide a very small amount of extra floodplain storage, but this

Category Long List Option Water Course / Description Take Forward for Reasoning / Notes / Past Study Reference Areas Affected assessment? Christchurch may be enough to act as compensatory storage Meadow/King’s for the demountable defence option. Meadow In order for this option to have a larger impact on flood risk in Caversham, it would have to be implemented on a very large scale, as part of a wider strategic option to maximise attenuation across the Thames floodplain along its entire length.

Appendix B: Outline Design Drawings

ENV0000112C-CH2-000-O00-DR-CI-1000 Reading and Caversham Defence Alignment ENV0000112C-CH2-00-400-DR-C-0011 Caversham Cross Sections 1 of 3 ENV0000112C-CH2-00-400-DR-C-0012 Caversham Cross Sections 2 of 3 ENV0000112C-CH2-00-400-DR-C-0013 Caversham Cross Sections 3 of 3 ENV0000112C-CH2-00-400-DR-C-0014 Reading Cross Sections 1 of 2 ENV0000112C-CH2-00-400-DR-C-0015 Reading Cross Sections 2 of 2

Appendix C: Do Nothing and Do Minimum Modelling Results

ENV0000112C-CH2-000-O00-DR-HY-0001 Do Minimum Flood Extents (present day) ENV0000112C-CH2-000-O00-DR-HY-0002 Do Minimum Flood Extents (after climate change)

Appendix D – Buildability Statement

ENV0000112C-JHY-000-O00-RP-CI-0001

Appendix E: Carbon Modelling Tool

ENV0000112C-CH2-000-O00-CA-CI-0001

Appendix F: Geotechnical Desk study ENV0000112C-CH2-000-O00-TN-GT-0001 Geotechnical Desk Study

Appendix G: Ground Investigation Report ENV0000112C-CH2-000-O00-RP-GT-0002 North Bank Ground Investigation Report

Appendix H: Project Costs

Cost Summary of Appraised Options: Reading and Caversham Flood Alleviation Scheme Whole Life Cash Cost

Option 2 Option 3 Option 4 Option 5 Option 6 Option 7 Assumptions Defences from Defences from Defences from Defences from Promenade Defences from Christchurch Promenade Promenade Road to Nire Description Item Road to Waterman Place Do Minimum playing fields to Road to Nire Road and Waterman Christchurch to Reading Nire Road Road (West & Place to Reading Bridge playing fields Bridge (South) (East) East) (West, East & South) (West) Cost to OBC Early Supplier Engagement £15,000 £15,000 £15,000 £15,000 £15,000 Ground Investigation £184,000 £184,000 £184,000 £184,000 £184,000 3 day per week PM, 0.5 day per week PE, 0.5 day per £93,184 £93,184 £93,184 £93,184 £93,184 EA Time week NEAS Other Consultants £7,500 £7,500 £7,500 £7,500 £7,500 Outline Business Case production £208,000 £208,000 £208,000 £208,000 £208,000 Total costs to OBC (Sub-total-1) £507,684 £507,684 £507,684 £507,684 £507,684 Detailed CH2M costs - Design, CDM duties, Consultation Accelerated works, design to planning, GIR inc. Design and & contracts. Planning, Supervision £256,475 £1,219,148 £1,441,793 £464,599 £1,932,509 supervision, modelling, design post-planning Construction Environment Agency Staff/ncpms/NEAS Full-time PM, 1 day per week PE, 1 day per week £57,078 £271,321 £320,871 £103,397 £430,080.00 NEAS, 1 day per week APM Engineering and Construction Contract personel (site supervisor, project manager and cost £117,600.00 £134,400.00 £193,200.00 £117,600.00 £243,600.00 Full-time supervisor, part-time ECW manager Estates/Land purchase/Compensation £13,272 £63,086 £74,607 £24,041 £100,000.00 Surveys e.g. GI, GPR, Ecological and Ecology, topographic, GPR, structural, GI, trial £68,747 £326,787 £386,466 £124,534 £518,000.00 Environmental trenching

Early Supplier Engagement £5,000 £20,000 £25,000 £15,000 £30,000

Procurement Sub-total-2 £518,172 £2,034,743 £2,441,937 £849,171 £3,254,189

Construction Staff £367,989 £987,609 £1,313,444 £678,532 £1,991,977 26.97% Base Cost Preliminaries £158,332 £424,932 £565,127 £291,948 £857,075.00 11.61% General Foreman £49,242 £132,156 £175,757 £90,797 £266,554.75 3.61%

Site Clearance £25,000.00 £75,000 £100,000.00 £15,000.00 £100,000.00 Services Diversion (minor only) Included in 10% risk Environmental Mitigation Included in 10% risk North Bank: Section AA £214,589 £214,589 £214,589 Section BB £408,648 £408,648 £408,648 Section CC £503,983 £503,983 £503,983 Section DD £158,887 £158,887 £158,887 Section EE £78,138 £599,056 £520,918 £520,918 Section FF £290,292 £290,292 £290,292 Section GG £243,335 £243,335 £243,335 Section HH £1,455,715 £1,455,715 £1,455,715 Section JJ £338,892 £338,892 £338,892 Section KK £254,174 £254,174 £254,174 Section LL £238,051 £238,051 £238,051 Section MM £241,843 £241,843 £241,843 South Bank: Section NN £113,812 £113,812 Section PP £35,218 £35,218

Cost Summary of Appraised Options: Reading and Caversham Flood Alleviation Scheme Whole Life Cash Cost

Reading Bridge By-Pass Channel (inc. fee) £4,448,574 £4,448,574 £4,448,574

Environmental enhancements/ landscaping Nominal allowance for works in Christchurch £45,000 £75,000 £75,000 £45,000 £75,000 Meadows, Christchurch Ditch, Hills Meadows and Amersham Park

Contractor Fee £121,297 £325,536 £432,939 £223,658 £933,610 8.89% £2,131,103 £10,130,165 £11,980,167 £3,860,456 £16,057,636 Sub-total-3

Mitigations None required £0 £0 £0 £0 £0 Sub-total-4

Base cost Subtotal (2+3+4) £0 £3,156,959 £12,672,592 £14,929,788 £5,217,311 £19,819,509 Risk Risk (50%ile Monte Carlo risk analysis) £603,388 £2,422,108 £2,853,525 £997,183 £3,788,096 19.11% Capital cost of scheme (including to OBC, including monte carlo risk) £3,760,347 £15,094,700 £17,783,313 £6,214,494 £23,607,605 Inflation Inflation at 2% £63,139 £253,452 £298,596 £104,346 £396,390 Total estimated Base cost + Monte Carlo 95%ile + inflation £0 £3,823,487 £15,348,152 £18,081,909 £6,318,840 £24,003,995 scheme cost Maintenance Yearly maintenance £2,080 £3,120 £3,120 £4,160 £3,120 £5,200 10 yearly maintenance £100k nominal allowance for pump hire and operation, £2,080 £58,700 £84,992 £143,412 £9,148 £150,480 10% of replacement costs for gate refurbishment 25 yearly maintenance Gate, sluice, and stoplog replacement extracted from £27,080 £63,920 £334,842 £396,683 £63,400 £458,003 ESE costs