Gateshead Council Level 1 Strategic Flood Risk Assessment

Volume II: SFRA Technical Report

Final Draft Report

October 2013

Development & Enterprise Gateshead Council Civic Centre Regent Street Gateshead NE8 1HH

JBA Project Manager Chris Isherwood BSc DipWEM MSc CEnv MCIWEM C.WEM JBA Consulting Bank Quay House Sankey Street Warrington WA1 1NN Revision History

Revision Ref / Date Issued Amendments Issued to

Gateshead Level 1 SFRA Gayle Wilson, Gateshead MBC Final Report Cameron Sked, EA 20 September 2011 Les Hall, NWL

Gateshead Level 1 SFRA Updated text to represent Gayle Wilson, Gateshead MBC Final Draft Report (update) NPPF, Gateshead Local October 2013 Plan and new flood risk datasets

Contract This report describes work commissioned by Gayle Wilson, on behalf of Gateshead MBC, by contract dated 16/07/2013. Gateshead MBC’s representative for the contract was Gayle Wilson. Chris Isherwood and Jonathan Cooper of JBA Consulting carried out this work.

Prepared by ...... Chris Isherwood BSc DipWEM MSc CEnv MCIWEM C.WEM Chartered Senior Analyst

Reviewed by ...... Gary Deakin BSc CEng MICE Director Purpose This document has been prepared as a Final Draft Report for Gateshead MBC. JBA Consulting accepts no responsibility or liability for any use that is made of this document other than by the Client for the purposes for which it was originally commissioned and prepared. JBA Consulting has no liability regarding the use of this report except to Gateshead MBC.

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Acknowledgements JBA would like to thank all those who provided information and data for this report. Special thanks go out to Gayle Wilson from Gateshead MBC, Cameron Sked and Sarah Baillie from the Environment Agency and Les Hall and Niki Mather from Northumbrian Water. Copyright © Jeremy Benn Associates Limited 2013 Carbon Footprint A printed copy of the main text in this document will result in a carbon footprint of 322g if 100% post-consumer recycled paper is used and 409g if primary-source paper is used. These figures assume the report is printed in black and white on A4 paper and in duplex. JBA is aiming to reduce its per capita carbon emissions.

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Executive Summary

Development and Flood Risk Gateshead MBC is required to undertake a Strategic Flood Risk Assessment (SFRA) as an essential part of the pre-production/evidence gathering stage of the Local Plan and preparation of the Sustainability Appraisal (SA). The requirement for and guidance on the preparation of SFRAs is outlined in the National Planning Policy Framework (NPPF) and its Practice Guide. This requires Local Planning Authorities (LPAs) to take a more dominant role in local flood risk management. They also need to demonstrate that due regard has been given to the issue of flood risk at all levels of the planning process to avoid inappropriate development. Local authority planners must demonstrate that a risk based, sequential approach has been applied in preparing development plans and that flood risk has been considered during the planning application process. This must be achieved through the application of the Sequential and Exception Test. By providing a central store for data, guidance and recommendations on flood risk issues at a local level, the SFRA is an important planning tool that enables the LPA to carry out the Sequential and Exception Test and to select and develop sustainable site allocations with regard to flood risk. SFRAs can also provide a much broader and inclusive vehicle for integrated, strategic and local Flood Risk Management (FRM) assessment and delivery, by providing the linkage between Catchment Flood Management Plans (CFMPs), Regional Flood Risk Appraisals (RFRAs) and Surface Water Management Plans (SWMPs). The suite of flood risk policy issues and information on the scale and nature of the risks in these various documents needs to be brought into “real” settings with the SFRA tasked with improving the understanding of flood risk across the districts.

Volume I - Guidance Report Volume I of the Gateshead SFRA introduces the SFRA process. It is an excellent reference document for current flood risk management drivers, national regional and local planning policy and introduced Environment Agency policy such as the Tyne CFMP. The report also provides a brief understanding of the mechanisms of flooding and flood risk for those new to the subject. More importantly, it provides a comprehensive discussion on NPPF, the Sequential and Exception Test and links the Flood Risk Management framework within national, regional and local flood risk assessments. This report provides guidance and recommendations to Spatial Planners, Development Management and Developers in how to apply the sequential approach by carrying out both the Sequential and Exception Tests, using the flood risk information provided in the Technical Report (Volume II).

Volume II - Technical Report Volume II provides the technical information and methods used in the assessment of flood risk across Gateshead. It initially begins with the introduction to the study area and the ‘Consultation & Data Management’ section, identifying key stakeholders and their involvement in the SFRA process followed by a review of important data sources within the SFRA. The main sections within the report focus on the assessment of all sources of flooding include; fluvial, tidal, surface water, sewers, groundwater and reservoirs and other artificial sources. Volume II also assesses current flood management measures including the Environment Agency Flood Warning System and flood defences. The SFRA has mapped all GIS flood risk data collected, which increase the level of detail outside of the provided in the Environment Agency Flood Map. Volume II along with the suite of SFRA maps provide the main evidence base of the Gateshead Level 1 SFRA. Providing the technical information in one volume allows the flood risk information to be easily viewed and updated when required.

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Section 5 provides the assessment of proposed development sites against the Flood Zones and surface water flooding information. A separate spreadsheet provides this analysis, which Gateshead MBC can use to apply the Sequential Test. This volume concludes with a number of key recommendations for further work including as Level 2 SFRAs and SWMPs, which will provide Gateshead MBC with a strategic and coherent framework for managing flood risk in their area.

Use of SFRA Data During the SFRA, a number of stakeholders provided flood risk datasets including Gateshead MBC, the Environment Agency and Northumbrian Water. All data received falls under specific data licence agreements between Gateshead MBC and the supplier. Gateshead MBC has been supplied with all flood risk data collected or produced during the SFRA in the form of reports, maps, GIS and modelled outputs. It is important that Gateshead MBC control these datasets internally. Gateshead MBC will be able to use any data for internal use as long as it falls within the license agreement and will publish the SFRA reports and Maps online. The context in which these datasets were produced must be considered for instance, any modelling undertaken for the SFRA is of a strategic nature and FRAs should seek to refine the understanding of flood risk from all sources to any particular site. Northumbrian Water and the North East local authorities are currently preparing a data sharing protocol to aid the exchange of mutually beneficial FRM information. The draft includes:  Roles and responsibilities  Provision of information  Confidentiality  Intellectual property  Data protection

The shared data used in the preparation of this document will be subject to the terms of the data sharing protocol and the corporate data protection / storage policies employed by Gateshead MBC. In the meantime, SFRA data should not be passed on to third parties outside of Gateshead MBC. Any third party wishing to use the flood risk datasets should contact the original holder of that data such as External Relations in the Environment Agency North East Region as a charge is likely to apply for its use. The same applies to any data supplied by Northumbrian Water.

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Contents Contents ...... v 1 Introduction ...... 1 1.1 Commission ...... 1 1.2 Gateshead SFRA ...... 1 2 Consultation & Data Collection ...... 3 2.1 Introduction ...... 3 2.2 Stakeholders ...... 3 2.3 Data Management, Review and Monitoring ...... 5 A Study Area & Flooding History ...... 7 2.4 Study Area ...... 7 2.5 Gateshead Flood History ...... 8 3 Fluvial and Tidal Flood Risk ...... 9 3.1 Introduction ...... 9 3.2 Flood Zones ...... 10 3.3 Main Rivers ...... 13 3.4 Ordinary Watercourses ...... 16 3.5 Significant Structures ...... 17 3.6 Flood Warning ...... 18 4 Surface Water Flooding ...... 19 4.1 Introduction ...... 19 4.2 Surface Water Runoff ...... 19 4.3 Sewers Flooding ...... 23 4.4 Flooding from Ground and Mine Water ...... 26 5 Flooding from Reservoirs & other Artificial Sources ...... 29 5.1 Reservoirs ...... 29 5.2 Lakes and Ponds ...... 29 6 Impacts of Climate Change...... 32 6.1 Climate Change Predictions ...... 32 6.2 Climate Change Impacts ...... 32 7 Development & Flood Risk ...... 36 7.1 Introduction ...... 36 7.2 Development & Flood Risk Screening ...... 36 7.3 Detailed Development & Flood Risk Review ...... 38 7.4 Additional Potential Development Sites ...... 52 8 SFRA Recommendations ...... 57 8.1 Introduction ...... 57 8.2 Level 2 Strategic Flood Risk Assessment ...... 57 8.3 Surface Water Management Plans ...... 58 8.4 Water Cycle Studies ...... 60 8.5 Green Infrastructure Framework ...... 60 8.6 Summary ...... 61 Appendices...... I B Digital Data Register ...... I C Historical Flood Incident Register ...... II D Allied Exploration & Geotechnics Ltd Groundwater Review ...... III

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E Flood Risk Screening Spreadsheet ...... IV F Glossary of Terms ...... V

List of Figures Figure 1-1: Gateshead SFRA study area ...... 7 Figure 1-2: Historical flood incidences by source ...... 8 Figure 3-1: North East hydrological linkages ...... 10 Figure 3-2: Number of properties within Flood Zone 2 ...... 12 Figure 3-3: Blackhall Mill culvert diversion ...... 15 Figure 4-1: Team Valley AStSWF and FMfSW comparison ...... 22

List of Tables Table 2-1: Regular updated datasets ...... 5 Table 3-1: Predicted properties at fluvial & tidal flood risk ...... 12 Table 3-2: Functional Floodplain mapping ...... 13 Table 3-3: River Derwent flood defence assets...... 14 Table 3-4: Previously designated Critical Ordinary Watercourses ...... 17 Table 3-5: Gateshead Flood Warning Areas ...... 18 Table 4-1: Comparative surface water modelling approaches ...... 21 Table 4-2: Properties at risk during the modelled 1 in 200-year rainfall event ...... 21 Table 4-3: NW DG5 register overview ...... 23 Table 4-4: Critical Drainage Areas ...... 25 Table 4-5: Groundwater and mine water flooding locations ...... 27 Table 5-1: Gateshead Artificial Water Bodies ...... 30 Table 6-1: Changes to river flood flows by river basin district compared to a 1961-90 baseline ...... 32 Table 6-2: Climate change effects on River Derwent peak water levels ...... 33 Table 6-3: Climate change effects on River Team peak water levels ...... 33 Table 6-4: Change to extreme rainfall intensity compared to a 1961-90 baseline ...... 34 Table 6-5: UKCP02 tidal projections ...... 34 Table 6-6: UKCP09 tidal projections ...... 34 Table 6-7: Tidal projections comparison ...... 34 Table 6-8: Environment Agency coastal extremes levels at Tynemouth ...... 34 Table 7-1: Potential development site flood risk categories ...... 37 Table 7-2: Number of potential development sites at risk ...... 37 Table 7-3: Summary of potential development sites at risk ...... 37 Table 8-1: CDA recommendations ...... 59 Table 8-2: Summary of future recommended studies ...... 61

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List of Maps

Set A - Historical Flood Incidents 2013s7359 – L1A – Map 1: Historical Flood Incident

Set B - Fluvial and Tidal Flood Risk 2013s7359 – L1B – Map 1 - 6: PPS25 Flood Zones 2013s7359 – L1B – Map 7: Functional Floodplain 2013s7359 – L1B – Map 8: Watercourse Names and Fluvial and Tidal Extents 2013s7359 – L1B – Map 9: 1 in 200-year Tidal Climate Change Sensitivity 2013s7359 – L1B – Map 10: 1 in 100-year Fluvial Climate Change Sensitivity

Set C - Surface Water Flood Risk 2013s7359 – L1C – Map 1: Areas Susceptible to Surface Water Flooding 2013s7359 – L1C – Map 2: Flood Map for Surface Water 2013s7359 – L1C – Map 3: SFRA Surface Water Flood Map 2013s7359 – L1C – Map 4: NW Drainage Areas and DG5 Rating 2013s7359 – L1C – Map 5: Critical Drainage Areas 2013s7359 – L1C – Map 6: Areas Susceptible to Groundwater Flooding 2013s7359 – L1C – Map 7: Groundwater and Mine Water Flooding

Set D - Reservoir Flood Risk and other Artificial Sources 2013s7359 – L1D – Map 1: Derwent Reservoir 2013s7359 – L1D – Map 2: Kielder Reservoir 2013s7359 – L1D – Map 3: Artificial Water Bodies

Set E - Flood Risk Management 2013s7359 – L1E – Map 1: Flood Risk Management Measures 2013s7359 – L1E – Map 2: Environment Agency and Local Planning Authority Byelaws

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Abbreviations ABD ...... Areas Benefitting from Defences AEP ...... Annual Exceedance Probability AMP ...... Asset Management Plan AStGWF ...... Areas Susceptible to Groundwater Flooding AStSWF ...... Areas Susceptible to Surface Water Flooding CDA ...... Critical Drainage Area CFMP ...... Catchment Flood Management Plan CRR ...... Community Risk Register CSO ...... Combined Sewer Overflow DCLG ...... Department of Communities and Local Government ELR ...... Employment Land Review FAS ...... Flood Alleviation Scheme FDGiA ...... Flood Defence Grant in Aid FEH ...... Flood Estimation Handbook FMfSW ...... Flood Map for Surface Water FRA ...... Flood Risk Assessment FRM ...... Flood Risk Management FRMP ...... Flood Risk Management Plan FRR ...... Flood Risk Regulations FWMA ...... Flood and Water Management Act GIS ...... Geographical Information Systems IMP ...... Indicative Floodplain Map LFRMS ...... Local Flood Risk Management Strategy LLFA ...... Lead Local Flood Authority LPA ...... Local Planning Authority LRF ...... Local Resilience Forum NEA ...... North East Assembly NFCDD ...... National Flood and Coastal Defence Database NPPF ...... National Planning Policy Framework NWL ...... Northumbrian Water Ltd PFRA ...... Preliminary Flood Risk Assessment PPG ...... Planning Policy Guidance PPM ...... Planned Preventative Maintenance PPS ...... Planning Policy Statement RBMP ...... River Basin Management Plan RFF ...... Regional Resilience Forum RFRA ...... Regional Flood Risk Appraisal RMA ...... Risk Management Authority

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RSS ...... Regional Spatial Strategy SA ...... Sustainability Appraisal SAB ...... SuDS Approval Board SFRA ...... Strategic Flood Risk Assessment SFRM ...... Strategic Flood Risk Mapping SHLAA ...... Strategic Housing Land Availability Assessment SoP ...... Standard of Protection SuDS ...... Sustainable Drainage Systems SWMP ...... Surface Water Management Plan TWFRS ...... Tyne and Wear Fire and Rescue Service uFMfSW ...... updated Flood Map for Surface Water UKCIP ...... United Kingdom Climate Impacts Programme WCS ...... Water Cycle Study WFD ...... Water Framework Directive

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1 Introduction

1.1 Commission Strategic Flood Risk Assessments (SFRAs) are a technical document providing an assessment of all types of flood risk that will form part of the evidence base for the Council’s Local Plan and will inform future land use planning decisions. Specifically, the SFRA will enable Gateshead MBC to apply the Sequential and Exception Tests; allocate appropriate sites for development; prepared supporting flooding policies; and identify opportunities for reducing flood risk. JBA produced the first Tyne & Wear SFRA in 2006 under the draft PPS25 to inform the Council LDF. The SFRA was reviewed following the introduction of PPS25 (2010), its Practice Guide (2009), Pitt Review recommendations (2008) and the Floods and Water Management Act (2010), and was reissued as the Gateshead Level 1 SFRA in 2011. Since 2011, here have been further developments in national planning and flood food risk information including the publication of the National Planning Policy Framework (NPPF). Gateshead has also experienced a number of flood events include those of 2012. As a result, Gateshead MBC commissioned JBA in 2013 to undertake a minor review of the Level 1 SFRA, primarily focussing on updating the reports with new flood risk and development guidance and updating the flood risk maps with new GIS datasets.

1.2 Gateshead SFRA

1.2.1 Aims and Objectives The aims and objectives of the Level 1 SFRA are:  To form part of the evidence base and inform the Sustainability Appraisal (incorporating the Strategic Environmental Assessment) for the Gateshead Local Plan.  To assist in the preparation of, and to make recommendations of, appropriate policies for management of flood risk within the Gateshead East Local Plan.  To understand flood risk from all sources and to investigate and identify the extent and severity of flood risk throughout Gateshead. This assessment will enable the Council to steer development away from those areas where flood risk is considered greatest, ensuring that areas allocated for development can be developed in a safe, cost effective and sustainable manner.  To enable the Council to meet its obligations under the NPPF and technical guidance.  To assess the suitability of potential development site allocations across the Borough including assessment of the direct and indirect impacts on flood risk.  To provide reference and a policy development user guide, to advise and inform wider stakeholders, including the public, private and commercial developers in order for them to understand their obligations under the latest planning guidance.  To supplement current policy guidelines and to provide a straightforward risk based approach to development management in the area.  To provide a reference document to which all parties involved in development planning and flood risk can reliably turn to for initial advice and guidance.  To develop a report that forms the basis of an informed development management process that also provides guidance on the potential risk of flooding associated with future planning applications and the basis for site specific Flood Risk Assessments (FRAs) where necessary.  To identify land required for current and future flood management that should be safeguarded as set out in the NPPF.

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1.2.2 SFRA Report The Gateshead SFRA has been prepared over two volumes covering flood risk policy, flood risk issues and development guidance. The structure of the reports has been written in sections, supported by mapping, which will enable users to identify and focus on their particular requirements and areas of interest. Volume I introduces the high-level documents that drive flood risk management at a national, regional and local scale. These documents have all influenced the preparation of this SFRA and their own guidance and recommendations have informed the flood risk detail and recommendations provided in Volume II (the technical flood risk report). This section also introduces regional policy drivers including CFMPs, which should influence the preparation of flood risk policies within the Local Plan. Volume II (this report) introduces the key sources and mechanisms of flood risk in Gateshead and measures that are taken to manage the risk. This Volume then provides sufficient data and information to inform the application of the Sequential Test by Gateshead MBC including a suite of strategic flood risk maps. To aid Gateshead MBC in undertaking the Sequential Test, a spreadsheet has been developed which provides the results of a spatial assessment for each proposed development site against Flood Zones and the Areas Susceptible to Surface Water Flooding map. The analysis includes area (ha) and percentage (%) cover of each zone and the proposed development land use. The Level 1 SFRA then provides recommendations for further work.

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2 Consultation & Data Collection

2.1 Introduction To carry out an appropriate and comprehensive assessment of flood risk across Gateshead it is essential to collate and build upon the best available data and studies already carried out. This information has been used to form the foundation of the SFRA. The SFRA process must consider flooding from all sources and this is only achievable through consulting with those stakeholders with specific interest or knowledge in other sources of flooding. This data collection process is a key part of the SFRA and has enabled this SFRA to be based on a significant amount of information that already exists on Gateshead. The NPPF and the FWMA identifies a number of key stakeholders (Risk Management Authorities). There are two main types of stakeholders: those that are consulted on their expert knowledge in a particular field and are requested to provide flood risk information and those who are consulted on the actual SFRA report. Each stakeholder and their involvement in the Gateshead SFRA are discussed below.

2.2 Stakeholders

2.2.1 Gateshead MBC This SFRA has been produced to support the Gateshead MBC Local Plan. The Council have helped scope the SFRA and provide the majority of local flood risk datasets. An initial SFRA meeting was held to discuss the requirements of NPPF in producing a Level 1 SFRA and to determine the main tasks needed to be completed. The meeting also outlined the Council’s own timetable relating to preparing an evidence base for their Local Plan. Gateshead MBC supplied numerous datasets including:  Potential development sites (Growth Point, SHLAA, Strategic Sites etc)  Historical flooding records  Surface water data including the Gateshead/Newcastle SWMP  Ordinary watercourse data  OS MasterMap

2.2.2 Environment Agency The Environment Agency is a statutory consultee for Local Plans under the NPPF. They are also a statutory consultee for planning applications. The Environment Agency has discretionary powers under FWMA manage flood risk and, as a result, hold the majority of flood risk data in the UK. Separate departments were consulted though the External Relations Team including Development Management, Flood Mapping and Reservoir Safety Teams on the SFRA approach and available data. A full list of data provided by the Environment Agency is available in the Data Register but the main datasets include:  Tyne Catchment Flood Management Plan  Flood Map  National surface water maps  Historical flooding records  Flood management assets (defences and flood warning areas)  LIDAR data

Environment Agency representatives were also on the SFRA steering group and were consulted on the draft version of the Gateshead SFRA report, with their comments included within the final report. Revisions of the SFRA reports and general changes made can be found on 'Revision History' section on Page i.

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2.2.3 Northumbrian Water Ltd Local water companies are a RMA under the FWMA and therefore have been consulted on potential flood risks associated with the sewer network. Sewers can be a significant source of flooding especially within urban areas. Northumbrian Water Ltd (NWL) holds a number of datasets on the public sewer network, which were made available for this study. The main datasets used included internal and external DG5 records (historical flooding register) at a strategic drainage area level, which has been used to understand to risk associated with the current drainage system. NWL were also consulted on the draft version of the SFRA and associated maps and their comments have been used to shape the final report.

NWL Consultation Recommendation

Gateshead MBC should continue to liaise with NWL once the SFRA has been completed. NWL have an important responsibility to play in future flood risk management and a good relationship has been established during the production of this SFRA.

2.2.4 Highways Agency All major roads and motorways have the potential to impact on flood risk. This is especially the case in an urban environment when roads can form potential flow routes or major structures such as bridges or culverts can significantly reduce the capacity of watercourses and therefore increase flood risk. Road networks that are at risk of flooding also have the potential for wider impacts reducing access and egress routes to and from sites which could increase the vulnerability of areas to flooding. The Highways Agency was consulted on all know flood incidences on their road networks. The Highways Agency forwarded this request on to A-One who manage and maintain the trunk roads and motorway network in the north east of England on behalf of the Highways Agency. A-One supplied a number of useful datasets including GIS road networks and photographs of key culverts underneath their networks.

2.2.5 Coal Authority It was identified early on in the scoping of the Gateshead SFRA that mine water rebound was a potential flood risk issue within the area. As a result, the Coal Authority was contact to obtain any information or previous work they have conducted in the area. The Coal Authority provided a detailed response outlining the main issues within Gateshead, which highlighted the need for a more detailed assessment of groundwater and main water flood risk than is usually undertaken within SFRAs. As part of the review on the first draft of the SFRA report Gateshead MBC contacted Allied Exploration & Geotechnics Ltd to review Section 4.4. Their review has been supplied within Appendix D with key pieces of information extracted and used within the final version of this SFRA.

2.2.6 Tyne & Wear Fire & Rescue Service Emergency services are a good source of historical flooding incident data. For instance when the fire brigade are called out to flood related incidences, they keep a detailed registers of all call outs that includes the source of flooding and the action taken. The Tyne and Wear Fire and Rescue Service (TWFRS) were extremely helpful in providing this information producing a database of over 300 flood related call outs dating back to January 2004.

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2.3 Data Management, Review and Monitoring

2.3.1 Data Management This SFRA should be viewed as a ‘living’ document that is anticipated to be used in the day-to- day process of planning and development. It is therefore important that datasets collected for the SFRA are transparent and accessible. A Digital Data Register has been produced and supplied to Gateshead MBC listing all data received throughout the SFRA process. All data was reviewed on receipt and its quality and confidence rated for use in the SFRA. This process was purely based on professional judgement and rated as high, medium and low. Most data requested was good quality and accurate as expected. Whilst the majority of the datasets could be mapped geographically (GIS) helping to visualise the risk of flooding others were not reducing its quality. Historical flooding information was generally marked as both medium quality and confidence, as whilst it could be placed on a map there was no metadata included identifying the source of flooding. The confidence in incident precision was also questionable; however, this would always be expected with historical flooding records. The Data Register will allow intended users of the SFRA to review the accuracy, currency and relevance of all datasets used and for a central group to manage and update datasets when needed. The organisations listed should be the first contact for any update to the SFRA to make sure the most up-to-date datasets are used. Digital Data Register can be found on the Gateshead MBC Level 1 SFRA Digital Deliverables DVD - Appendix B Folder Whilst all data collected and produced during the SFRA process has been supplied to Gateshead MBC (report, maps, GIS, modelled output) there should be controls on its use. It is anticipated that the SFRA report (all volumes) and associated maps will be published on the Council's website as PDFs as the central source of SFRA data and available to download. Gateshead MBC will be able to use the modelled output (depths, hazards and outlines) and GIS data provided for internal use. This use of this information must consider the context within which it was produced. The use of this data will fall under the license agreement between the Council and the Environment Agency as it has been produced using Environment Agency data. It should be remembered that the modelling undertaken for the SFRA is of a strategic nature and FRAs that are more detailed should seek to refine the understanding of flood risk from all sources to any particular site. SFRA GIS data should not be passed on to third parties outside of the Council. Any third party wishing to use existing Environment Agency flood risk datasets should contact External Relations in the Environment Agency North East Region. A charge is likely to apply for the use of this data.

2.3.2 SFRA Review and Monitoring There are a number of key outputs from possible future studies and dataset, which are known to be regularly updated. These should be incorporated in any update to the SFRA. All datasets collected for the SFRA have been supplied to Gateshead MBC in the form of SFRA reports and maps. GIS data used to produce the maps have also been supplied. If maps or the SFRA report are updated, they should be reissued to the relevant stakeholders. Table 2-1 contains a list of these datasets. Not all future sources of information should trigger an immediate full update of the SFRA; however new information should be collected and kept alongside the SFRA until it is updated. Table 2-1: Regular updated datasets

Dataset Sources Updates Tyne CFMP Environment Agency Updated every 5 years Updated Quarterly – actual updates Flood Zones – significant Environment Agency in Gateshead will depend on model change extensions to the Derwent & Team models as part of future floodplain

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Dataset Sources Updates mapping studies NFCDD Environment Agency Ongoing Significant Flood Events All Unknown Planning Policy CLG Unknown Completion of SWMP Gateshead MBC On Completion and/or Drainage Strategy

SFRA Monitoring Recommendation

Whilst this SFRA has been produced using the most up-to-date national guidance and flood risk data, it is recommended that the SFRA should be updated on a regular basis. The Environment Agency has suggested this be every 3 to 4 years, unless there is a significant flood affecting the area, arising to new information or areas at flood risk. A review of the SFRA should also be undertaken if there are any major national policy changes, including updates to the NPPF and the PPS25 Practice Guide.

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A Study Area & Flooding History

2.4 Study Area The study area for this SFRA includes the administrative boundary of Gateshead MBC as illustrated in Figure 2-1. Gateshead is located in North East of England and is one of five metropolitan districts that compromise the conurbation of Tyne & Wear. Gateshead falls within the Northumbria River Basin District, served by the Environment Agency North East region and one water company, Northumbrian Water Ltd (NWL). Gateshead is bordered to the north by Newcastle City Council, to the west by Northumberland County Council, to the south by Durham County Council and the east by South Tyneside Council and Sunderland City Council. The regional hydrology of Gateshead is influence primarily by the River Tyne, Derwent and Team, fed through a network of tributaries that flow into the main channels from higher ground. The River Tyne is a major focal point of the Council and its banks are the location of major development including the MetroCentre and Gateshead’s town centre. The River Derwent originates outside of Gateshead MBC's administrative boundary in Tynedale/Wear Valley. The river system begins from the Derwent reservoir, west of Consett, flowing in a northerly direction before eventually discharging into the River Tyne. Historically, flow into the Team would have originated in part on the eastern side, from the areas of Low Fell, Saltwell, and Harlow Green, westwards along Chow Dene, Dodds Dene, Longacre Dene, Saltwell Dene and Aller Dene to interconnect with the main river channel located on lower ground. Continued mine pumping has generally rendered these tributaries inactive, although in the long term this situation may be reversed if groundwater levels were allowed to recharge. It is likely that a number of the denes along the eastern side of the Team Valley have also been culverted. The Team discharges into the River Tyne between Dunston and Teams. Figure 2-1: Gateshead SFRA study area

© Crown copyright and database rights 2013 Ordnance Survey Gateshead MBC 100019132

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2.5 Gateshead Flood History Records of past flooding are useful for looking at the sources, seasonality, frequency and intensity of flooding. Historical records are often anecdotal and incomplete and it can be difficult to determine accurately the frequency and consequences of events, but they are useful for providing background information. Gauged records and registers of flooded properties are more valuable for estimating flood frequency and severity at different locations. Within Gateshead, there have been four major recent flood events, in March 1979, November 2000, September 2008 and June 2012. In these events flooding resulted from a variety of sources including:  Ordinary watercourse (channel exceedance, culvert blockage and tidal locking)  Sewer surcharge  Surface water runoff  Highway runoff  Groundwater  Mine water

121 flooding incidents have been recorded in the database dating back to 1979; however, the majority of incidents occurred from 2000 onwards. 98 of these historical incidents are from local sources (under LLFA responsibility). Figure 4-1 provides a summary of information specific to each source of flooding considered as part of the PFRA. Figure 1-2: Historical flood incidences by source

Appendix C provides an electronic database of all historical flooding incidents collected during the SFRA. Data includes the location (easting & northing if available), source of flooding where possible, number of properties affected and the organisation who supplied the data. 2013s7359 – L1A – Map 1 illustrates all historical records collected. Developers should use the map in order to identify any historical events that have occurred on their site and advice sought from the Council if there are historical flood events in the vicinity.

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3 Fluvial and Tidal Flood Risk

3.1 Introduction Gateshead contains 52km of designated main rivers including the River Tyne, Derwent, Team and Don. The mechanism of flooding along these rivers can be described as both tidal and fluvial in nature. Tidal flooding along watercourses is caused by extreme tide levels exceeding river ground / bank / defence levels. In the case of Gateshead, this means extreme tide levels along the River Tyne caused by high tides or storm surges in the North Sea. Flooding along estuaries can be complex and difficult to predict because it is influenced not just by the volume of fresh water travelling down the estuary from the river system, but also by the height of tides and tidal surges coming up the estuary. Tidal flood events usually dominate in these circumstances and have greater influence on peak water levels than fluvial events. The tidal limit usually identifies the extent of the tidal influence of flooding. Fluvial flooding of watercourses is associated with the exceedance of channel capacity during higher flows. The process of flooding on watercourses depends on a number of characteristics associated with the catchment including; geographical location and variation in rainfall, steepness of the channel and surrounding floodplain and infiltration and rate of runoff associated with urban and rural catchments.

3.1.1 Hydrological Linkages The majority of rivers within Gateshead originate outside the Council's administrative boundary. Although it is likely that small land use changes within Gateshead will only have localised impact on river flows, major land use changes in the upstream catchments of the River Tyne, Derwent and Team could have a significant impact on their flow regime and, therefore, flood risk. Figure 3-1 illustrates fluvial hydraulic linkages within the North East. Gateshead is mainly a receiving district when considering the River Derwent and Team. Upstream land use changes could affect of fluvial flood risk along these two watercourses. The main potential adverse impacts that future development may have on downstream areas are twofold:  Reduction in floodplain storage capacity  Reduction in rainfall infiltration and increased runoff

These issues highlight the need for the North East Councils and the Environment Agency to work together during flood risk management, particularly where actions could exacerbate flooding in downstream communities (e.g. in the upper/middle reaches of the North and South Tyne have important impacts on Gateshead, Newcastle upon-Tyne, North Tyneside and South Tyneside District Councils). The need for consistent regional development policies controlling runoff or development in floodplains within contributing districts is therefore crucial as this would have wider benefits for Tyne and Wear authorities as a whole as well as Gateshead MBC. This should be carried out by the successful implementation of the NPPF and the Sequential Test. Appropriate flood risk management policies will also be needed in the Local Plan. Volume I discusses the requirement to control runoff rates in further detail.

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Figure 3-1: North East hydrological linkages

Red = Receiving District, Orange = Receiving & Contributing District, Green = Contributing District (pre 2009 district boundaries)

3.2 Flood Zones

3.2.1 Environment Agency Flood Map The Environment Agency Flood Map provides an overview of areas considered susceptible to flood risk in the study area as a result of fluvial and tidal flooding. These maps have been prepared in a consistent manner across England and Wales and provide an estimation of the extent of flooding for the 1 in 100-year fluvial, 1 in 200-year tidal and both 1 in 1000-year fluvial and tidal flood events. The Flood Zone maps were originally prepared using a methodology based on the national digital terrain model (NextMap), derived river flows (Flood Estimation Handbook (FEH)) and two- dimensional flood routing. However, since their release they have been consistently been updated with detailed outlines derived from hydraulic models where available.

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The Environment Agency and Gateshead MBC has investigated a number of watercourses that pose the greatest flood risk including the River Tyne, Derwent and Team. Outputs from these modelling studies have been used to update the Indicative Floodplain Map. 1. Gateshead Level 2 SFRA (2010) The 2010 Gateshead Level 2 SFRA prepared a 1D-2D hydraulic model of the River Tyne and lower reaches of the River Derwent and Team. The rivers were modelled using the ISIS-TUFLOW modelling software and developed using the Environment Agency's HEC- RAS models below. The SFRA model outputs were used to update the Environment Agency Flood Map. 2. River Tyne and Derwent Flood Risk Mapping Study (2005) A Section 105 Flood Risk Mapping Study was undertaken by the Environment Agency in 2005 to assess the extent and risk associate with the two watercourses. The modelling work undertaken included a steady state HEC-RAS model for the River Tyne reaches one and two and the River Derwent Reach 1 (upstream boundary of Dam Head). 3. River Team Section 105 Study (2000) A flood risk mapping study was undertaken by the Environment Agency in 2000 to assess the extents for both fluvial and tidal events along the River Team. The flood extents were developed through the construction of a steady state HEC-RAS model. The model extends from the upstream face of Urpeth Bridge to the confluence with the River Tyne. The model was updated in 2006 by the Environment Agency as part of the River Team Pre-Feasibility Study. The study included converting the model into an unsteady state model, calculating new hydrological inflows and making small changes to the channel geometry and structures.

The outputs from these studies have been used to update the theoretically derived Flood Zone extents. The remaining watercourses flood zone extents are still based on broad scale modelling and have not been modelled in detail. The Environment Agency Flood Zone Maps are precautionary in that they do not take account of flood defences because these can be breached, overtopped and may not be in existence for the lifetime of the development and, therefore, represent a worst-case extent of flooding. They do not consider other forms of flooding and do not take account of climate change.

3.2.2 NPPF Flood Zones NPPF divides the country into three flood zones, Flood Zones 1, 2 and 3, corresponding to areas of low, medium and high flood risk, respectively. The NPPF Flood Zones have been produced on a set of maps 2013s7359-L1A-Map 1 to 12 covering Gateshead. Environment Agency Flood Zones issued in May 2013 has been used as the latest Flood Zones in this area, whilst the functional floodplain has been delineated using the method outline below. The NPPF Flood Zone map illustrates:  Main rivers  Named ordinary watercourses  Un-named watercourse  Flood Zone 2  Flood Zone 3a  Flood Zone 3b (Functional Floodplain)  Proposed development sites

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The NPPF map should be used when undertaking the Sequential Test by Spatial Planners, and individual developers according to the PPS25 Practice Guide. 2013s7359-L1A-Map 14 illustrates the mechanism of flooding, separating both Flood Zone 2 and 3 into tidal and fluvial flood risk zones. Table 3-1 provides a count of the total number of properties within Flood Zone 2 and 3. This assessment was carried out using a simple GIS process. Table 3-1: Predicted properties at fluvial & tidal flood risk

Property Type Total Properties Flood Zone 3 Flood Zone 2 Residential 92,375 142 436 Non Residential 13,354 140 424 Total 105,729 282 860

Figure 3-2: Number of properties within Flood Zone 2

© Crown copyright and database rights 2013 Ordnance Survey Gateshead MBC 100019132

3.2.3 Functional Floodplain Flood Zone 3b, the Functional Floodplain, was defined in the 2008 Gateshead SFRA using the following criteria:  Land subject to flooding in the 1 in 20 or 1 in 25 year flood event  Land where water has to flow or be stored in times of flood (e.g. washlands)  Land already benefiting from defences or those which are developed and/or sustainable has not been considered as Functional Floodplain  Major transport infrastructure (e.g. motorways and railways) have also been excluded from functional floodplain areas, as well as the removal of ‘dry islands’ defined using the ‘size standards’ within the Environment Agency SFRM Specification for Flood Risk Mapping1

1 Environment Agency (2006) Strategic Flood Risk Management Specification for Flood Risk Mapping. Release 1.2.

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The approach used to define the functional floodplain for each watercourse is summarised in Table 3-2. The 2008 Functional Floodplain was reviewed as part of this SFRA update as there had been a number of changes to Flood Zone 3. 2013s7359-L1A-Map 13 illustrates the functional floodplain extent. Table 3-2: Functional Floodplain mapping

Watercourse Extent Data Source Black Burn Marshall Lands Farm to TVTE Flood Zone 3 Blaydon Burn Spenside Farm to River Tyne Flood Zone 3 Tyne and Derwent Flood Risk River Derwent From Dam Head to the River Tyne Mapping Study (March 2005) 1 in 25 year outline River Derwent Upstream of Dam Head Flood Zone 3 River Don Reach within Gateshead Flood Zone 3 Urpeth Bridge to River Tyne. River Team Pre-Feasibility Study River Team Lamesley pastures have also been (April 2006) 1 in 20 year outline defined as functional floodplain River Team Upstream of Urpeth Bridge Flood Zone 3 1 in 25 year outline is constrained River Tyne Mouth of River Tyne to Wylam Bridge to the river channel and therefore not shown as functional floodplain Stanley Burn Red Burn to River Tyne Flood Zone 3

Functional Floodplain Recommendations

Urban Areas Some urban areas offer a floodplain function in providing storage or conveyance routes during a flood event. The identification of these areas is difficult during a Level 1 SFRA and therefore has been omitted from the functional floodplain identification process.

Un-modelled & Minor Watercourses Some stretches of the Derwent and Team have not been modelled in detail. In these areas, it has been necessary to make precautionary assumptions about the extent of the functional floodplain. In most cases, Flood Zone 3 has been used as a guide in defining the extent as recommended in PPS25. The Environment Agency have also identified a number of inaccuracies in Flood Zone 3 on minor watercourses, in particular non-main rivers due to scale and misalignment issues including Blaydon Burn, Urpeth Burn and Black Burn in the Team Valley.

Recommendation As it is critical that the outline for the functional floodplain is as accurate as possible, the true extent in these areas should be assessed in more detail during any detailed site-specific FRA.

3.3 Main Rivers

3.3.1 River Tyne The Tyne drains a large portion of North East England (2,300km² at its tidal limit). It rises in the west on the peaty moorlands of the North Pennines and flowing eastwards across relatively impervious geology, mainly consisting of Carboniferous Limestone covered by drift and boulder clay, before entering the North Sea at Tynemouth. The majority of the Tyne, and nearly all of its catchment, lies upstream of the conurbation of Tyneside and is almost exclusively rural. The significant towns upstream of Tyneside are Corbridge and Hexham.

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The upland catchments of both the Tyne and the Derwent have been utilised for large water resource schemes, including Kielder Water and the Derwent Reservoir. Kielder is important for supplying water to Tyneside and the wider northeast of England via transfer tunnels. Derwent reservoir is smaller than Kielder (surface area 3.8km² versus 10.9km²). It is a supply reservoir, which means water is piped directly from the impoundment to a water treatment works. The only controlled releases from the dam are for compensation flow. Other human influences include gravel extraction, metal mining and afforestation. All of these activities have changed the flow 2 regimes and ecology of both rivers . Water levels in the Tyne estuary and lower Derwent are influenced by a combination of tide level and fluvial flow events, but occurrences of flooding are known to be predominantly tidal. Issues of joint probability and dependence have been investigated but ultimately the tidal and fluvial variables were assumed independent3. It was found that the critical event for the whole of the Tyne study reach and the Derwent as far upstream as the A1 was entirely dominated by the tide and the Derwent upstream of the A1 was entirely dominated by fluvial flows. The majority of the Environment Agency Flood Zones are constrained in bank along the River Tyne due to its large channel capacity. As mentioned above the critical flood event on this stretch of river is more likely to be tidal than fluvial. Areas with a history of flooding include small sections of Newburn and Dunston surround the confluence of the River Derwent and Team with the Tyne. Downstream the Flood Zones once again remain in bank. Along the River Tyne in Gateshead, there are no flood defences. As the area is dominated by tidal flooding, previous development has been raised above flooding levels.

3.3.2 River Derwent Flood Zones along the River Derwent within Gateshead are relatively narrow and are predominantly on rural land. The areas of Blackhall Mill and Lintzford have been identified in the Tyne CFMP as the main areas at flood risk, which will require maintaining the current level of flood defence. Blackhall Mill benefits from a flood defence on the River Derwent. Currently the raised flood bank is protecting the properties along River View from an estimated flood frequency of 1 in 15- years4. Blackhall Mill has been subjected to major flooding in 1993, 1995, 2000 and in September 2008 when properties had to be evacuated due to high river levels. Flood Zones downstream of Axwell Park are extensive covering a number of residential and commercial properties. Floodwaters are also constrained around major road infrastructure of the A1 and the railway line providing possible access and egress difficulties. Along the River Derwent there are two man-made raised defences at Blackhall Mill and Winlaton Mill. The Winlaton Mill raised flood bank is situated on the right-hand bank and protects this area from fluvial flooding. The Blackhall Mill raised defence is situated on the left-hand bank and protects those properties along River View. Table 3-3: River Derwent flood defence assets

Defence Maintainer Asset Type SOP U/S Level D/S Level Condition Location Raised 55.32 55.29 Blackhall Mill EA 50yr Unknown defence mAOD mAOD Raised 11.39 10.07 Winlaton Mill EA 25yr Unknown defence mAOD mAOD

The flood embankment at Blackhall Mill was initially constructed in the 1950’s to a 1 in 50-year Standard of Protection (SoP); however, it was raised and capped with clay following the 2000 floods. Whilst the probability of flooding is reduced as a result, the defence cannot eliminate risk as flooding was experienced in September 2008. The Derwent defence recently withstood over

2 Archer, D (2003) Tyne and Tide. Daryan Press 3 JBA (2003) Rivers Tyne and Derwent Flood Mapping Study 4 Correspondence between Gateshead Council and Environment agency ( 2001) R. Derwent Flood Defences at Blackhall Mill

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a 1 in 100-year flood in September 2008, however the cause of flooding during this event was due to a Mill Race, which flows to the east of the village. The Mill Race is culverted and is known to cause flooding due to blockages and during high river levels in the Derwent. The Environment Agency has recently completed a culvert diversion of the Mill Race, moving the outfall 300m downstream of the bridge, which is not affected by high Derwent levels and expected to provide a 1 in 100-year SoP. Figure 3-3 illustrates the culvert diversion and new main river centreline. Figure 3-3: Blackhall Mill culvert diversion

© Crown copyright and database rights 2013 Ordnance Survey Gateshead MBC 100019132

Derwent Defence Assets Recommendation

Currently, NFCDD does not provide the condition of existing flood defences in Gateshead, as this information is not available. The condition of defences is critical to understand the residual risk associated with them including the risk of breaching. It is recommended that a structural engineer should collect this information during a Level 2 SFRA through consultation with the Environment Agency or during a walk over survey. Until this information is available, any proposed development within the vicinity of these defences should undertake an assessment of their residual risks during a site-specific FRA. This should include the assessment of overtopping during the 1 in 1000-year event and breaching during the 1 in 100-year event, including an allowance for climate change for both scenarios.

3.3.3 River Team The Team Valley lies on the south bank of the Tyne between the rivers Derwent and Don, and drains an area of 86km². The catchment is diverse, of medium relief (falling from 250m AOD at its source to sea level). The catchment includes parts of the settlements of Whickham, Annfield Plain, Stanley (northern part), Birtley and central Gateshead. There has been coal mining in much of the catchment and open cast mining still takes place at Kibblesworth. The major tributaries to the Team are the Blackburn Brook, Strandy Burn, and Rowletch Burn, although these are relatively small tributaries, with catchment areas of no more than 10km².

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Flood Zones south of the A1 are wide covering large areas rural farmland. However, the lower 6km of the channel lies in an entirely urbanised area and the reach through the Team Valley Industrial Estate is heavily engineered and partly culverted. Flood Zones through this reach are narrow with the 1 in 200-year fluvial event remain in channel in sections. Further downstream north of the railway line, the Flood Zone once again become wide placing large areas of residential properties at risk around the areas of Teams and Dunston. Flood protection along the Team is mostly due to areas of high ground. A capital scheme has been proposed to mitigate the risk of tidal flooding and there is a private wall providing protection near the River Tyne confluence5. The Environment Agency maintains the high ground channel at St. Omaghs Haugh and Derwenthaugh/Swalwell and these have routine checks carried out on them. A feasibility study has been carried out by the Environment Agency into the possibility of a scheme for the tidal part of the River Team, which could include a series of defences along the river’s edge. One option was to protect residential properties, which would require a defence across the road to tie into high ground, raise the road or to provide temporary defences. However, the feasibility study recommended that a defence scheme would not be beneficial in the short term. The Environment Agency has also investigated the use of Lamesley pastures for upstream flood storage in an attempt to reduce risk downstream through the trading estate and offset the impacts of climate change. However, as the risk downstream is already considered low, this is not a high priority and further investigations have not been carried out by the Environment Agency. In order to safeguard this land for possible future flood risk management it has been classified as functional floodplain within this SFRA.

Lamesely Floodplain Recommendation

Any Level 2 SFRA should assess the ability of the Lamesely pastures for floodplain storage. It should involve the review of the Environment Agency investigation and a strategic assessment of the ability of the floodplain to provide sufficient future flood storage. This should aid Gateshead MBC allocate and safeguard sites for flood storage.

3.3.4 River Don The Don catchment covers an area of 48.9km² in South Tyneside, Gateshead and Sunderland. The river forms part of the boarder between Sunderland and South Tyneside before flowing northwesterly towards Boldon. At this point, the river cuts back and flows north towards its confluence with the River Tyne at Jarrow. The major tributaries to the Don include the Bede’s Burn, Monkton Burn, Calfclose Burn and Usworth Burn. Flooding along the River Don in Gateshead is constrained to a small stretch of rural land placing no properties at risk.

3.4 Ordinary Watercourses Ordinary watercourses are those that are not designated as Main River and therefore come under the control of the LLFA, who have Permissive Power to carryout works should this be deemed necessary. All named ordinary watercourses have been identified in Gateshead using an OS 10k map and are illustrated on Map 2013s7359-L1A-Map 14. Un-named watercourses (small watercourses and drains) have also been identified on the same map and are available in the GIS layer produced for the SFRA. It must be noted that it may be possible that not all watercourse have been identified, especially if they are small rural or private drains which have not been identified on a standard OS 10k map. A number of the ordinary watercourses within the Tyne catchment were previously designated by the Environment Agency as Critical Ordinary Watercourses (COWs). This designation reflects a known issue with respect to flooding, and is generally associated with (for example) limited

5 Environment Agency (2005) River Tyne Catchment Flood Management Plan: Scoping Report

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channel capacity, channel constrictions and/or a poor maintenance regime. In 2006/7 the Environment Agency enmained all the remaining COWs and took over responsibility for their maintenance and management. All the previous COWs are now defined as ‘Main Rivers’. Table 3-4 presents a summary of previously designated COWs within Gateshead. Table 3-4: Previously designated Critical Ordinary Watercourses

COW Catchment Location Length (km) Lady Park Burn River Team Lady Park/ TVTE 0.89

For the purposes of the SFRA, flooding issues in respect of former COWs have been considered a good summary of the entire current non-main river flooding issues, although when FRAs are undertaken, full consultation with the Environment Agency and relevant Local Authorities should take place. Gateshead MBC has also identified a number of ordinary watercourses, which are known to have a history of flooding mainly related to culverts including: 1. Lady Park Burn – Coach Road Piggery, Lady Park 2. Landswood Terrace – Winlaton Mill 3. Bute Road North – High Spen 4. Bradley Burn – South Lodge, A695 Crawcrook 5. Mill Race – Riverview, Blackhall Mill

3.5 Significant Structures The flood risk management assets previously discussed relate to main defences such as raised defences or flood embankments. However, it is known that there are a number of ‘private’ or non-maintained assets that may provide a level of protection within Gateshead or influence the level of flood risk. Some of these can be described as significant structures such as bridges, culverts, weirs or buildings, which influence local hydraulics and increase the risk of flooding to adjacent areas or areas further downstream. The Environment Agency NFCDD goes some way in identifying these structures. Gateshead MBC should also keep a regard of local structures or assets within an Asset Register as required under the FWMA. As part of the SFRA, Gateshead MBC provided a list of key culverts that are known to have an impact on flood risk, which included:  Blackhall Mill, Mill Race culvert  Winlaton Mill, un-named watercourse culvert  Coalburns, Coal Burn culvert  Blaydon Burn culvert  Lamesley, Lady Park Burn culvert  Team Valley, Black Burn (A1/Dukesway) culvert

2013s7359-L1F- Map 1 illustrates all flood risk management measures, which have been identified through the SFRA. This map is very important when considering the residual risks associated with flooding and includes:  The location of river flood defences (based on NFCDD)  The coverage of Environment Agency Flood Warning Areas  Significant structures such as culverts, bridges, viaducts and weirs

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Significant Structures Recommendation

Where future development is being proposed on land that may benefit from local structures, a Level 2 SFRA should assess residential risks associated with asset failure. Gateshead MBC should also keep a register of key assets in an Asset Register required under the FWMA.

3.6 Flood Warning There are a number of Flood Warning and Flood Watch areas that cover Gateshead MBC, some of which cross over its administrative boundaries. There are three Flood Watch Areas including: 1. River Tyne (ref. code: 121WAFNF910) 2. Rivers Derwent, Team, Don and estuary tributaries (ref. code: 121WAFNF912) 3. Tyne Estuary (ref. code: 121WAFNF913)

Each of these Flood Watch Areas is split into Flood Warning Areas and is covered by Floodline Warnings Direct described in Table 3-5. 2013s7359-L1F- Map 1 illustrates all flood risk management measures, which have been identified through the SFRA, including the location of each area covered by Flood Warnings. Table 3-5: Gateshead Flood Warning Areas

Code Name Description River Derwent at Properties and low lying areas around River View, 121FWF321 Blackhall Mill Nursery Court, Derwent Street and Mill Court. River Derwent at Properties and low lying areas around Wood Street, Blaydon-on-Tyne, Lintzford Mill, Riverside Way, The Copse, Bates 121FWF323 Rowlands Gill, Lintzford, Lane, Hexham Road, and The Sands Industrial and Shotley Bridge Estate River Derwent at Properties around The Pavilion, Hexham Road, and 121FWF324 Swalwell The Covers Properties at Eddy's Bridge, Leadmill Bridge, 121FWF325 River Derwent Allensford, Shotley Bridge, Ebchester Bridge, Blackhall Mill, Lintzford, and Rowlands Gill Properties at, Willington Boat Club, Walker at Wincomblee Estates, and Team Valley Industrial 121FWT549 Tyne Estuary Riverside Estate. Also Ravensworth Road and Whickam Junction in Dunston and Bridge Road and lower Haugh Lane Industrial estate in Derwent Haugh. Properties including, Howdon Pans, Newcastle Quayside, and the Enterprise Park at Dunston. 121FWT550 Tyne Estuary Also Hannington Works and upper Haugh Lane Industrial Estate in Derwent Haugh. Tyne Estuary, upper Areas including Festival Way Estates at Dunston 121FWT551 Dunston and and the Industrial Estate, Delta Park and Clasper Derwenthaugh Way in Derwent Haugh.

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4 Surface Water Flooding

4.1 Introduction Surface water flooding, in the context of the Gateshead SFRA, includes:  Surface water runoff as a result of high intensity rainfall when water is ponding or flowing over the ground surface before entering the underground drainage network or watercourse, or cannot enter it because the network is full or at capacity, thus causing flooding. This is known as pluvial flooding. Pluvial flooding also includes overland flows from the urban/rural fringe entering the built up area.  Sewer flooding, which occurs when the capacity of the underground system is exceeded due to heavy rainfall, resulting in flooding inside and outside of buildings. Sewer flooding in 'dry weather' resulting from blockage, collapse or pumping station mechanical failure is not included as this is a sole concern of the drainage undertaker.  Flooding from groundwater, where groundwater is defined as all water, which is below the surface of the ground and in direct contact with the ground or subsoil. This includes overland flows resulting from groundwater sources.

4.2 Surface Water Runoff There are a number of national and local datasets available on surface water flooding in Gateshead. The Environment Agency has produced a national assessment of surface water flooding in the form of two national mapping datasets. This SFRA has also produced its own local surface water flood map. Surface water mapping available to Gateshead MBC, including the:  Environment Agency's national Areas Susceptible to Surface Water Flooding map  Environment Agency's national Flood Map for Surface Water  SFRA Surface Water Flood Map

All three maps are extremely helpful in supplementing the NPPF Flood Zone Map as they show where localised, flash flooding can cause problems, even if the Main Rivers are not overflowing. This is often due to high intensity rainfall events, which exceed the capacity of the piped drainage systems. As a result, surface water is unable to drain away safely and flooding results.

4.2.1 Areas Susceptible to Surface Water Flooding Map 2008 The first-generation national mapping, Areas Susceptible to Surface Water Flooding (AStSWF) released in 2008, shows areas where surface water would be expected to flow or pond using three susceptibility bandings for a rainfall event with a 1 in 200 chance of occurring. The simplified modelling method adopted excludes the underground sewerage, drainage systems, smaller over ground drainage systems and buildings. The first-generation map was procured as a preliminary national output to provide Local Resilience Forums (LRFs) with an initial indication of areas that may be susceptible to surface water flooding. It was also provided to:  Regional Resilience Teams for use in their functions which relate to emergencies as defined and as required by the Civil Contingencies Act 2004  LPAs for land use planning purposes

The AStSWF map is a valuable piece of data as it provides an indication of the likelihood of surface water flooding, separated into areas at less, intermediate or high susceptibility. The areas that have been identified as 'highly' susceptible to surface water will flood first, flood deepest and flood during lower rainfall events. These areas will also tend to be predominantly located in valley bottoms, in the Main River floodplain or on flat low-lying land, which are generally also at fluvial risk.

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From the maps, it can also be seen that there are many areas of land outside Flood Zone 3 and 2 that are susceptible to surface water flooding. These are typically located on tributaries and feeder streams to Main Rivers, where steeper sloping valleys exist and on the edge of the natural floodplain of Main Rivers, again where land levels tend to rise more steeply.

4.2.2 Gateshead Surface Water Flood Map 2009 Prior to the release of the FMfSW in 2010, JBA produce a local surface water model for Gateshead in 2009, which looked to improve the AStSWF map by including:  Higher resolution LIDAR data  The influence of buildings and road networks

The Gateshead surface water modelling outputs were provided to the Council as part of the 2011 SFRA. The extent and variation in flood depths was classified into low, medium and high susceptible zones. Although the SFRA surface water flood map is considered more detailed than the AStSWF map as it takes account of local catchment characteristics, it should only be viewed at a strategic scale to identify critical flow paths and areas susceptible to ponding of surface water.

4.2.3 Flood Map for Surface Water 2010 In 2010, the Environment Agency updated their national methodology and released their second- generation national map, the Flood Map for Surface Water (FMfSW). The revised model included a number of improvements to the AStSWF and Gateshead surface water flood map including:  Two storm events (1 in 30-year and 1 in 200-year)  National infiltration rates  The influence of buildings  The influence of the sewer system

The results from each storm event were subdivided into zones:  Shallow surface water flooding (flooding greater than 0.1m)  Deep surface water flooding (flooding greater than 0.3m)

The Environment Agency chosen the 0.3m threshold as it represents a typical value for the onset of significant property damages. It is also at this depth that moving through floodwater (driving or walking) may become more difficult; both of which may lead users to consider the need to close roads or evacuate areas.

4.2.4 Surface Water Map Comparison This SFRA maps all three surface water datasets. The FMfSW is the newer and therefore primary source of nationally derived information supported by the AStSWF map and the Gateshead surface water map. Ultimately, Gateshead MBC should decide which information to use, supported by local knowledge and historic records. There is a higher likelihood that the FMfSW will be more representative in steeper areas, where topography influences inundation, rather than drainage and buildings. Whilst the AStSWF and the Gateshead surface water map will be more representative of large flat landscapes or where local sewer capacity is able to drain less than 6mm/hr. Considering this, there will be locations where the FMfSW underestimates the area of land at risk. It is important that Gateshead MBC review, discuss, agree and record, with the Environment Agency, Northumbrian Water and other interested parties, which surface water flood data best represents their local conditions, known as locally agreeing surface water information and should be carried out within the SFRA, SWMP and/or PFRA process. In order to help identify the difference in the three datasets, Table 4-1 lists each approach taken and difference in modelling variables adopted.

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Table 4-1: Comparative surface water modelling approaches

Surface Water Modelling Outputs in Gateshead Areas Susceptible to Flood Map for Variable SFRA Surface Water Surface Water Flood Surface Water Mapping (AStSWF) (FMfSW) Date 2008 2009 2010 Coverage National Gateshead National Modelling Package JFlow JFlow JFlow Annual Probability 1 in 30 1 in 200 1 in 200 Rainfall 1 in 200 Storm Duration 6.5 hrs 6.5 hrs 1.1 hrs Rainfall Profile 50% summer 50% summer 50% summer 100% urban 100% urban 70% urban Percentage Runoff 100% rural 100% rural 39% rural 0mm/hr urban 0mm/hr urban 12mm/hr urban Sewer Capacity 0mm/hr rural 0mm/hr rural 0mm/hr rural 0.1 rural 0.1 rural 0.1 rural Manning’s ‘n’ 0.1 urban 0.1 urban 0.03 urban Infoterra bare earth DTM LIDAR and Geo- EA LIDAR EA 2010 composite Perspectives Buildings Not represented DTM raised by 5m DTM raised by 5m Roads lowered by Roads Not considered Not considered 150mm less: 0.1 to 0.3m less: 0.1 to 0.3m less: >0.1m Threshold Bands intermediate: 0.3 to 1m intermediate: 0.3 to 1m more: >0.3m more: >1m more: >1m

On reviewing the modelling methodologies adopted, the FMfSW provides the best representation of local conditions in Gateshead, which suggests that it becomes the ‘locally agreed surface water information’. The model used for the FMfSW uses the latest methodology developed by the Environment Agency and the best available information. Figure 4-1 provides a comparison between the FMfSW (1 in 200-year) and the AStSWF (1 in 200-year) flood maps in an area known to be at risk of surface water flooding. The comparison illustrates a significant difference in surface water extents between the two maps, with the AStSWF flooding a greater area. This difference is similar throughout Gateshead. To provide a greater understanding of the impacts of this difference, Table 4-2 provides the number of properties at risk during the 1 in 200-year rainfall event for all three surface water datasets. Simple GIS has been used to calculate the number of properties within each flood zone band. Table 4-2: Properties at risk during the modelled 1 in 200-year rainfall event Non- Residential Properties at Residential National Dataset Banding Properties at Risk Properties at Risk Risk Less 19,700 16,100 3,600 AStSWF 2008 Intermediate 8,500 6,600 1,900 More 1,700 1,300 400

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Non- Residential Properties at Residential National Dataset Banding Properties at Risk Properties at Risk Risk Less 3,100 2,300 800 Gateshead Surface Intermediate 1,100 600 500 Water Map 2009 More 300 100 200 >0.1m 14,900 13,000 1,900 FMfSW 2010 >0.3m 5,400 4,600 800

Figure 4-1: Team Valley AStSWF and FMfSW comparison

© Crown copyright and database rights 2013 Ordnance Survey Gateshead MBC 100019132

Table 4-2 shows that the AStSWF contains the greatest number of properties at risk of surface water flooding. This is mainly due to the modelling methodology adopted and the fact that there was no reduction in rainfall to represent percentage runoff or drainage capacity. In other words, a larger volume of water was reaching the ground model and flowing over land. The local surface water modelling undertaken in 2009 considerably underestimates the number of properties at risk. Whilst the methodology adopted improves flood flow representation, there is a reduction in properties at risk due to the decision to block buildings out of the urban floodplain. The FMfSW provides a best of both worlds. The FMfSW modelling approach includes both percentage runoff and drainage capacity within the rainfall calculations, which produces a better representation of reality. Whilst the FMfSW uses this same approach of blocking buildings out of the urban floodplain, the Environment Agency went through a detailed process of producing an 'inelegant buffer' around its surface water flood extent to make sure it includes properties which may be inundated.

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From this analysis, the FMfSW is considered as providing the best representation of local conditions in Gateshead and should be the ‘locally agreed surface water information’. The remaining two datasets will provide good supporting information.

4.2.5 Areas at Risk of Surface Water Flooding The detailed surface water map identified a number of areas, which are highly susceptible to surface water flooding including the area of Blaydon and the Metro-Centre, Ryton and the Team Valley Trading Estate. All three locations are situated at the bottom of steep valleys or along the River Tyne corridor, in which surface water is likely to pool in low-lying areas producing significant flood depths and extents. In September 2008 and June 2012, there were a number of locations that suffered from local surface water flooding including:  Barlow Lane, Winlaton  Clare Vale Gardens, Clara Vale  Garesfield Lane, Pinewoods  Lintzford Lane Highfield  Pennyfine Road, Sunnyside

Flooding cause several roads to close on roundabouts between South Sherburn, Winlaton Mill and Swalwell, whilst part of Pennyfine Road was washed away.

4.3 Sewers Flooding Northumbrian Water (NWL) provided internal and external DG5 records at a strategic drainage area level (July 2013). Table 4-3 provides an overview of DG5 records in Gateshead aggregated to NWL drainage areas. Drainage areas have been attributed with a DG5 rating, suggested by NWL below:  - No properties on the register  Low < 10 properties on internal register  Medium < 10 properties on internal register and some on external register  High > 10 properties on internal register and some on external register

Table 4-3: NW DG5 register overview Internal External Drainage Area 1 in 1 in 2 in Tot 1 in 1 in 2 in Tot Rating 10 20 10 al 10 20 10 al Bensham 1 1 0 2 1 0 1 2 Med Birtley 0 0 3 3 3 1 2 6 Med Blaydon East 0 0 0 0 0 0 0 0 Blaydon Haugh 0 0 0 0 0 0 0 0 Blaydon West 0 0 1 1 0 2 1 3 Med Causey 0 0 0 0 0 0 0 0 Chopwell Wood 0 0 0 0 0 0 0 0 Chopwell/ Blackhall Mill 0 0 0 0 0 0 0 0 Chowdene 0 0 0 0 0 0 0 0 Coalburns 0 0 0 0 0 0 0 0 Crawcrook 0 0 0 0 0 0 1 1 Low Derwent View 0 0 0 0 0 0 0 0 Derwenthaugh 1 0 3 4 0 2 1 3 Med Dunston & Lobley Hill 0 0 2 2 0 1 0 1 Med Dunston Hill 0 1 0 1 0 0 2 2 Med Dunston/Teams 0 0 3 3 0 0 2 2 Med Felling & Felling

Foreshaw 0 0 0 0 0 0 0 0 Friars Goose 0 0 1 1 0 1 0 1 Med Gateshead Central 0 0 0 0 0 0 0 0 Gateshead 3 4 3 10 3 1 0 4 High

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Internal External Drainage Area 1 in 1 in 2 in Tot 1 in 1 in 2 in Tot Rating 10 20 10 al 10 20 10 al Stadium/Mount Pleasant Gateshead West 0 0 0 0 0 0 0 0 Heworth 0 1 0 1 0 0 0 0 Low Kibblesworth 2 0 0 2 1 0 0 1 Med Leam Lane/

Wardley/Bill Quay 0 0 0 0 0 0 0 0 Marquis of Granby 0 0 0 0 0 0 0 0 Prudhoe 1 1 5 7 1 0 6 7 Med Ryton East 0 0 0 0 0 0 0 0 Ryton West 0 0 0 0 0 0 0 0 Team Valley 0 0 0 0 0 0 0 0 Whickham North 1 1 0 2 0 1 0 1 Med Whickham South & Med Sunniside 0 0 1 1 0 0 2 2

Some capital projects within the region may either be ongoing, planned our even finished which may have reduced these figures. 2013s7359-L1C–Map 2 illustrates NWL drainage areas and their rating as described in Table 4-3. This map should be used to identify those locations where there may be a hydraulic incapacity in the sewer network. Whilst this map does not necessarily mean that there are drainage problems within the area, as DG5s are historically flooded properties (July 2013) not current risk areas, it should be used as a starting point for further consultation with NW, Gateshead MBC and the Environment Agency. Surface water and foul flows from new large-scale development may need to connect to the current drainage network, which could already have capacity issues. Adding further pressure on the system could place that new development site at risk of flooding and exacerbate the issue to the surround community. NWL drainage areas are also not all entirely within Gateshead MBC and connect to surrounding local authorities (i.e. South Tyneside). If the drainage area is at capacity, then further development could exacerbate the risk further downstream outside of the administrative boundary of Gateshead MBC. Gateshead MBC should use this information to develop flood risk and development control policies. As this map based on NWL drainage areas only (underground), it should be used in conjunction with the suite of surface water flood maps (overland). Critical Drainage Areas identified below should also be used to obtain a full appreciation of surface water and drainage flooding and their interactions.

4.3.1 Critical Drainage Areas Critical Drainage Areas (CDAs) have been proposed by combining NWL drainage areas (with a high number of DG5 records, see Table 4-3) and those which interact with other sources such as urban watercourses and surface water flooding. Contributing natural catchments have also been identified for those CDAs as the source or surface water flooding may originate outside of the drainage area but still contribute to the overall risk. Natural catchments were derived from the Flood Estimation Handbook (FEH) CD-ROM. 2013s7359-L1C–Map 3 illustrated CDAs in Gateshead. These CDAs are viewed as draft and will be reviewed during the Gateshead Level 2 SFRA where they will be assessed against more detailed flood risk information either produced during the assessment or supplied by NWL.

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Table 4-4: Critical Drainage Areas

Contributing Natural CDA Location Reason for CDA Definition Catchments High risk from drainage area. River Team and Rowletch Birtley High risk of surface water Burn flooding Leam Lane, Wardley & Medium risk from drainage area Un-named watercourse Bill Quay Blaydon West Medium risk from drainage area Blaydon Burn No contributing Felling & Felling Shore Medium risk from drainage area watercourse Medium risk from drainage area. River Derwent, Clock Burn Derwenthaugh High risk of surface water & Thornley Burn flooding. No contributing Dunston Hill Medium risk from drainage area watercourse No contributing Dunston & Lobley Hill Medium risk from drainage area watercourse The Dene and Whinney Bensham Medium risk from drainage area House Dene Multiple sources of flooding River Team, Black Burn, Team Valley High risk of surface water The Dene, Whinney House flooding Dene and Lady Park

Section 8 uses CDAs to identify the requirement for FRAs, Drainage Impact Assessments (DIAs) and high Level Surface Water Management Plans (SWMPs). Within CDAs, an increase in the rate of surface water runoff and/or volume from a new development may exacerbate the degree of flood risk to areas downstream or to the surrounding community. FRAs would have to demonstrate that the development would not adversely affect existing flooding conditions in these critical areas and should define and address the constraints that will govern the design of the drainage system and layout of the development site. Developers should look to reduce to greenfield run-off for a brownfield site and control to greenfield run-off for a greenfield site. Ideally, Gateshead MBC should work closely with the Environment Agency, NWL and individual developers to ensure surface water runoff is controlled as near to the source as possible which will include the application of SuDS.

CDA Recommendation

In CDAs, a site-specific Flood Risk Assessment (FRA) or Drainage Impact Assessment (DIA) would be expected regardless of which Flood Zone. This does include a Level 1 FRA, which would require consultation between the developer, Environment Agency, Gateshead MBC and NWL to identify the level or risk to that site. Volume I describes the levels of FRAs detail. PPS25 Practice Guide recommends that those developments greater than 1ha will require a FRA, however by using a more stringent trigger of 0.5ha within CDAs highlights the need for development to consider the current flood risk issues when planning their drainage system or implementing SuDS. N.B. The NPPF states a FRA will be required for all proposals for new development (including minor development and change of use) which has critical drainage problems. The Environment Agency has not identified any critical drainage problems in Gateshead.

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4.4 Flooding from Ground and Mine Water Due to the legacy of coal mining in the North East, the groundwater table in the Gateshead area has been maintained at an artificially low level by continuous pumping from the disused Kibblesworth shaft. It is expected that the groundwater level at the extraction point is between - 75 to -90 mAOD, although levels will increase away from the shaft due to the hydraulic gradient and local barriers restricting mine water flow. Conjecturally, the regional groundwater level in central Gateshead is expected to reside between -48 to -62 mAOD6. Flood risk is not the only consequence of groundwater/mine water discharging, there are also wider environmental and engineering (stability) effects. However, flood risk is the centre of this assessment. There are two main groundwater-flooding mechanisms, which may affect the Gateshead area.

4.4.1 Groundwater Flooding associated with the High in Bank River Levels There are no flood defences along the River Tyne through Gateshead to elevate the river level above the floodplain; it is therefore unlikely that alluvial groundwater flooding will occur. Tides are the main control on the River Tyne in Gateshead and this will limit the possibility of groundwater flooding, as the diurnal tide duration means that it is unlikely that there will be a period of extended high in bank river levels. However, there is the small possibility that multi peak events could sustain a high in bank river level for up to twelve hours. Overall, the risk of alluvial groundwater flooding is small for a river of this size. Other rivers in the Gateshead, such as the River Derwent and Team, are smaller than the Tyne. Floodplains surrounding smaller rivers are less prone to groundwater flooding as the rivers tend to be of a flashier nature and are less likely to have extended periods of high in-bank river levels. The floodplain and alluvial deposits of the River Derwent Valley, which constrain the area that potential could be affected by groundwater flooding, are relative narrow with little development. This coupled with the size of the river means that the likelihood of groundwater flooding and the potential impacts associated with it are low. The River Team is smaller than the Derwent, so the potential for groundwater flooding associated with it is also expected to be low and the type of trading estate developments along its lower reaches are unlikely to have basements, which would be at high risk to groundwater flooding.

4.4.2 Groundwater Flooding associated with Mine Water Rebound Gateshead has historically been undermined producing two ‘blocks’ of mine workings, the Kibblesworth Block and the Chaterhaugh Block, with dewatering occurring in each. The Chaterhaugh Block extends from the River Tyne in the North to Durham in the South. The pumping regime in the Chaterhaugh Block is likely to change in the near future to a more sustainable situation, using a gravity drain system rather than the pumping solution currently used. This is likely to result in a 15m rebound in groundwater levels in the Chaterhaugh Block area, increasing the minewater levels in Gateshead to around 10 mAOD7. A maximum potential level of 60 mAOD could be achieved on higher ground. Following this change, there is the potential for minor mine water discharges along the River Tyne and other watercourses in the area. Mine water in the Kibblesworth block flows, with the hydraulic head, north to south controlled at Kibblesworth. In the block, the National River Authority8 (now the Environment Agency) identified four potential discharge points for mine water due to their low elevation and Gateshead MBC identified two areas, which have a known history of mine water and groundwater flooding.

6 Allied Exploration & Geo-techniques Ltd (2009) SFRA Groundwater Study 7 Coal Authority (2008) Letter Report – Gateshead Flood Risk Response

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Table 4-5: Groundwater and mine water flooding locations

Name Location Risk Dunston Shaft Dunston Potential discharge points for mine water Norwood Shaft Dunston Potential discharge points for mine water Swalwell Henry Shaft Swalwell Potential discharge points for mine water Swalwell Henry Adit Swalwell Potential discharge points for mine water Addison Industrial Estate Ryton Historical mine water flooding Monkridge Gardens Dunston Hill Historical groundwater flooding

There is a low likelihood of significant discharges occurring from these locations as records show them to be backfilled. Backfilling will reduce the rate at which mine water may discharge. Additionally, there appear to be no plans to change the pumping regime in the Kibblesworth Block so mine water level should not be subject to significant rises in elevation. The potential water quality of the mine water is expected to be better than other areas of the Durham Coalfields with an Iron concentration of 30-150 mg/l and a pH of 5 to 7 but compared to most natural systems this is still high.9 It is not expected that areas of Gateshead will be at risk from mine water flooding though there may be one or two discharges into the Rivers Tyne, Team or Derwent as point discharges from known low elevation mine entries. These point discharges will release mine water thus controlling its level and preventing further rise. It is currently unknown whether developed low-lying areas, overlying areas with mine dewatering will experience groundwater flooding once the dewatering ceases. This type of groundwater flooding has been observed in other UK coalfield regions could affect areas that were wet prior to the mining of the area. The underground coal-mining situation is extremely complicated (with interconnected roadways, shafts, staples, backfill etc.) reliable postulating the effects of groundwater rise is considered impracticable in these conditions. Although this SFRA has identified clear candidates for the location of mine water flooding, the actual scale of the problem is unlikely to be clear.

4.4.3 Groundwater and Mine Water Flood Maps Areas Susceptible to Groundwater Flooding Map The Environment Agency’s national dataset, Areas Susceptible to Groundwater Flooding (AStGWF), provides the main dataset used to assess the future risk of groundwater flooding. The top two susceptibility bands of the British Geological Society (BGS) 1:50,000 Groundwater Flood Susceptibility Map derives the AStGWF map and thus covers consolidated aquifers (chalk, sandstone etc., termed 'clearwater' in the data attributes) and superficial deposits. It does not take account of the chance of flooding from groundwater rebound. The AStGWF map uses four susceptible categories to show proportion of each 1km grid square where geological and hydrogeological conditions show that groundwater might emerge. It does not show the likelihood of groundwater flooding occurring. In common with the majority of datasets showing areas which may experience groundwater emergence, this dataset covers a large area of land, and only isolated locations within the overall susceptible area are actually likely to suffer the consequences of groundwater flooding. Unless an area identified as ‘susceptible to groundwater flooding’ is also identified as ‘at risk from surface water flooding’, it is unlikely that this location would actually experience groundwater flooding to any appreciable depth, and therefore it is unlikely that the consequences of such flooding would be significant. SFRA Groundwater and Mine Water Flood Map 2013s7359-L1D–Map 1 illustrates minework blocks, springs and issues (identified from Ordinance Survey) and identified potential mine water discharge points.

9 National Rivers Authority (1993) A Study of the Regional Hydrogeology of the Durham Coalfield and the Potential Impact of Ceasing Mine Dewatering, Wardell Armstrong, Newcastle-upon-Tyne

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Springs and issues are locations where mine water and groundwater have been known to discharge. In the future, the rate of discharge from these locations may increase; especially in the Chaterhaugh Block if the proposed pumping regime changes occur, causing groundwater levels to rise. This is not a comprehensive map and it should be borne in mind that Gateshead has numerous recorded mineshafts, and potentially a similar number of unrecorded entries. However, the potential and significance of any mine water discharge in the Gateshead is low.

Groundwater & Mine Water Recommendation

Any site-specific FRA should assess the risk of groundwater/mine water flooding. It is expected however that most low-lying development areas in the Gateshead would have been raised before development to mitigate the potential for tidal flooding, which would have also mitigated groundwater flooding. Gateshead MBC should consult further with the Environment Agency and the Coal Authority in revisiting the Wardell Armstrong study to evaluate how realistic groundwater levels quoted are in relation to the ceasing of mine water pumping.

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5 Flooding from Reservoirs & other Artificial Sources

5.1 Reservoirs A reservoir is usually an artificial lake where water is kept for use. Some reservoirs supply water for household and industrial use, others serve other purposes, for example, as fishing lakes or leisure facilities. The risk of flooding associated with reservoirs is residual and is associated with failure of reservoir outfalls or breaching. Reservoirs in the UK have an extremely good safety record with no incidents resulting in the loss of life since 1925. The Environment Agency is the enforcement authority for the Reservoirs Act 1975 in England and Wales. All large reservoirs must be regularly inspected and supervised by reservoir panel engineers. Local authorities are responsible for coordinating emergency plans for reservoir flooding and ensuring communities are well prepared. Local authorities will work with other members of the Local Resilience Forum (LRF) to develop these plans.

5.1.1 Reservoir Flood Map The Environment Agency has recently prepared reservoir flood maps for all large reservoirs that hold over 25,000 cubic meters of water as defined in the Reservoirs Act 1975. There are two large reservoirs, situated outside Gateshead, which would pose a risk to property and life if a breach were to occur. These include the:  Kielder Reservoir  Derwent Reservoir

The maps do not give any information about the depth or speed of the floodwaters, rather the largest area that might be flooded if a reservoir were to fail and release the water it holds. The Environment Agency used a consistent national approach to produce the maps, which display a realistic worst-case scenario. These maps have been provided within this SFRA for emergency planning purposes only.

5.2 Lakes and Ponds Whilst large reservoirs provide the obvious source of residual flood risk from artificial sources, there are a number of smaller water bodies within the area. Smaller water bodies pose some risk to the immediate area as they may not be regularly expected and/or maintained. Gateshead MBC supplied a list of all artificial water bodies (lakes and ponds) located within Gateshead. Table 5-1 lists all water bodies provided, flood risk comments and discharge method. Each water body has been reviewed against the Environment Agency Flood Map and the SFRA surface water flood map. Two of the nineteen water bodies have a history of flood related problems, which include Stargate Pond and Woodside Lane.

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Table 5-1: Gateshead Artificial Water Bodies

Name Location Use OS (NZ) Flood Risk Comments Discharge PLR (NZ) Located within River Tyne tidal Flood Wellington Road, Acer Pond Nature 22176250 Zone 3 and area susceptible to Unknown None Dunston surface water flooding Not known (assumed Angel Of The Rockcliffe Way, Fishing 28175705 No obvious risk highway drain and None North Lakes Eighton Banks watercourse) Located within River Derwent tidal Axwell Park Spa Well Road, Culverted watercourse to Leisure 19616226 Flood Zone 2 and area susceptible to None Lake Blaydon River Derwent surface water flooding Blaydon Quarry Lead Road, Ryton Settling ponds 16336274 No obvious risk None None Bradley Park Sled Lane, Nature 12356316 No obvious risk None None Pond Crawcrook Spa Well Road, Located within River Derwent fluvial Clockburn Lake Nature 18446027 Channel to River Derwent None Winlaton Mill Flood Zone 3 Crawcrook Located within area susceptible to Crawcrook Settling ponds 12726376 None None Quarry surface water flooding Grange Lonnen, Culverted watercourse to Drover’s Pond Nature 14616434 No obvious risk 14648409 Ryton public sewer Oliver Millford, Leam Located within area susceptible to Henderson Park Leisure 29556100 Pipe to public sewer 29615001 Lane surface water flooding Lake Pipe to highway drain to Path Head Ryton Crawcrook Nature 16776349 No obvious risk Path Head Burn to River None Quarry Ponds Bypass, Blaydon Tyne Path Head Hexham Old Settling ponds 16946322 No obvious risk None None Quarry Road, Blaydon Pelaw Quarry Mill Lane, Pelaw Nature 31076257 No obvious risk Unknown None Lake Riding Wood Sled Lane, Culverted watercourse to Nature 12766327 No obvious risk None Ponds Crawcrook Bradley Burn

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Name Location Use OS (NZ) Flood Risk Comments Discharge PLR (NZ) Ryton Willows Located within area susceptible to Peth Lane, Ryton Nature 15626491 Ditch to River Tyne None Ponds surface water flooding Saltwell Park Located within area susceptible to West Park Road Leisure 25356150 Pipe to public sewer 25612003 Lake surface water flooding Located within River Derwent tidal Shibdon Road, Pipe to ditch to public 20631203 Shibdon Pond Nature 19496281 Flood Zone 2 and area susceptible to Blaydon sewer to River Tyne 20631207 surface water flooding Pipe to highway drain to Stargate Lane, Stargate Ponds Nature 16356315 Historically known to flood Path Head Burn to River None Ryton Tyne Watergate Bank, Watercourse to Black Watergate Lake Nature 22326015 No obvious risk None Lobley Hill Burn to River Team Highway storm Pipe to highway drain to Woodside Pond Ryton 14926373 Historically known to flood 14649001 water storage public sewer

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6 Impacts of Climate Change

6.1 Climate Change Predictions Over the past century across the UK, we have seen sea level rise and more of our winter rain falling in intense wet spells. Seasonal rainfall is highly variable. It seems to have decreased in summer and increased in winter, although winter amounts changed little in the last fifty years. Some of the changes might reflect natural variation, however the broad trends are in line with projections from climate models. Greenhouse gas (GHG) levels in the atmosphere are likely to cause higher winter rainfall in future. Past GHG emissions mean some climate change is inevitable in the next twenty to thirty years. Lower emissions could reduce the amount of climate change further into the future, but changes are still projected at least as far ahead as the 2080s. There is enough confidence in large-scale climate models to say that we must plan for change. There is more uncertainty at a local scale but model results can still help us plan to adapt. For example, we understand rainstorms may become more intense, even if we are unsure about exactly where or when. By the 2080s, the latest UK climate projections (UKCP09) are that there could be up to three times as many days in winter with heavy rainfall (defined as more than 25mm in a day). It is plausible that the amount of rain in extreme storms (with a 1 in 5 annual chance, or rarer) could increase locally by 40%. If emissions follow a medium future scenario, UKCP09 projected changes by the 2050s relative to the recent past are:  Winter precipitation increases of 10% (very likely to be between 0 and 23%)  Precipitation on the wettest day in winter up by 11% (very unlikely to be more than 24%)  Relative sea level at Tynemouth very likely to be up between 7 and 38cm from 1990 levels (not including extra potential rises from polar ice sheet loss)  Peak river flows in a typical catchment likely to increase between 8 and 13%

The tables below provide national estimates of how climate change will impact upon peak river flow, extreme rainfall intensities and relative mean sea level rises across Northumbria. Climate change factors have been extracted from UKCP02 and UKCP09. UKCP09 data has been extracted from the Environment Agency's guidance note10.

6.2 Climate Change Impacts

6.2.1 Climate Change Impact on Fluvial Flows As illustrated in Table 6-1, peak flows are likely to increase by around 20% by 2080. This translates into higher water levels. Table 6-1: Changes to river flood flows by river basin district compared to a 1961-90 baseline Total potential Total potential Total potential Applies across change anticipated change anticipated change anticipated Northumbria for 2020s for 2050s for 2080s Upper end estimate 25% 30% 50% Change factor 10% 15% 20% Lower end estimate 0% 0% 5% H++ estimate 35% 45% 75%

No climate changes outlines were available for this SFRA and as a result, it is not possible the map the impact of climate change of fluvial flood extents. In order to assess the impacts of

10 Environment Agency guidance document - Adapting to climate change: Advice for Flood and Coastal Erosion Risk Management Authorities

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climate change on fluvial flood events, a 20% increase on fluvial flood flows have been modelled using the Environment Agency's River Derwent and Team hydraulic models. The resulting peak water levels have been extracted and provided in Table 6-2 and Table 6-3. Table 6-2: Climate change effects on River Derwent peak water levels Current Base Climate Change Location Level (mADO) Scenario (mAOD) Dam Head 6.10 6.45 Derwent Rugby Ground 5.02 5.39 Sands lane Cricket Ground 4.73 5.07 The Hurrocks Allotment Gardens (vicinity of tidal 3.59 3.88 limit) Derwent Haugh 2.86 2.99 Tyne Confluence 2.83 2.97

Table 6-3: Climate change effects on River Team peak water levels

Current Base Climate Change Location Level (mADO) Scenario (mAOD) Downstream of railway line 5.14 5.36 Upstream of Derwentwater Road 5.02 5.24 Low Team Bridge 4.79 4.92 Derwentwater Footbridge (vicinity of tidal limit) 3.81 4.27 Works off east Ropery Road 3.68 4.23 Upstream of Team Street 3.67 4.22

To obtain an understanding of the impact of flood extent, a comparison can however be made between Flood Zone 2 and 3 to provide a strategic overview of what Flood Zone 3 could look like when including climate change. Whilst peak flood levels will increase as highlighted in the above tables the extent of flooding does not increase significantly when comparing the two zones along most of the watercourses. This is mainly associated with the well-defined floodplain limits of these river valleys. Increases in sea levels will also have an impact on fluvial flooding. It is probable that there will be an increase in the instances of fluvial flooding occurring on the lower reaches of the Derwent and Team and other drains close to the Tyne because of prolonged high tides. There are a few locations, where a significantly increased extent caused by both tidal and fluvial climate change is noticeable by comparing Flood Zone 3 and 2, including:  Derwenthaugh Industrial Estate  The Sands Industrial Estate  Land North and south of New Derwent Bridge including cricket, football and rugby grounds

6.2.2 Climate Change Impact on Rainfall Intensity Table 6-4 provides national estimates of how climate change will impact upon rainfall through the next century based on the UKCP09 projections. Understanding future rainfall intensity will be important when calculating future runoff from new development and designing drainage and attenuations systems (SuDS). The current national surface water mapping does not include a climate change scenario so it was not possible to map the impacts of increase rainfall intensity of surface water flooding.

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Table 6-4: Change to extreme rainfall intensity compared to a 1961-90 baseline

Total potential Total potential Total potential Applies across all change anticipated change anticipated change anticipated of England for 2020s for 2050s for 2080s Upper end estimate 10% 20% 40% Change factor 5% 10% 20% Lower end estimate 0 5% 10%

6.2.3 Climate Change Impact on Tidal Levels UKCP02 and UKCP09 predict two different climate change factors for sea level rise. Table 6-5: UKCP02 tidal projections

Sea level rise mm/yr Scenario 1990 to 2025 2025 to 2055 2055 to 2085 2085 to 2115 N/A 2.5 7.0 10.0 13.0 from table B.1 of PPS25

Table 6-6: UKCP09 tidal projections

Applies across all Sea level rise mm/yr of England up to 2025 2026 to 2050 2051 to 2080 2081 to 2115 H++ scenario 6 12.5 24 33 Upper end estimate 4 7 11 15 Use UKCP09 relative sea level rise medium emission 95% projection Change factor for the project location available from the user interface. Use UKCP09 relative sea level rise low emission 50% projection for the Lower end estimate project location available from the user interface.

Table 6-7: Tidal projections comparison

Date UKCP02 UKCP09 (Change factor) 1990 – 2025 +90mm +158mm 1990 – 2050 +265mm +303mm 1990 – 2085 +600mm +553mm 1990 – 2100 +795mm +676mm

As can be seen from the tables above, UKCP09 projections are higher over the short to medium term. However, over the long term (100ys) UKCP02 projections are higher. As a worst case scenario, UKCP02 projections have been used to calculate the effects of climate change on tidal levels at a point offshore from Tynemouth provided by the Environment Agency. Tidal increases have been calculated from a 2011 base level. Table 6-8: Environment Agency coastal extremes levels at Tynemouth

Tidal Flood Extreme Sea Level in 2025 Climate Change 2080 Climate Change Event 2011 (mAOD) Level (mAOD) Level (mAOD) 1 in 10-year 3.46 3.508 3.683 1 in 25-year 3.58 3.628 3.803 1 in 50-year 3.67 3.718 3.893 1 in 100-year 3.76 3.808 3.983

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Tidal Flood Extreme Sea Level in 2025 Climate Change 2080 Climate Change Event 2011 (mAOD) Level (mAOD) Level (mAOD) 1 in 200-year 3.86 3.908 4.083 1 in 1000-year 4.11 4.158 4.333

As Gateshead is located further up the Tyne estuary, these effects are dampened. However, whilst predicted climate change affects are smaller along the River Tyne to those along the coast, the impact of climate change has a significant impact on flood risk in Gateshead. The sensitivity of a particular location and land use to climate change can be factored into decisions regarding floor levels, building uses and safe access etc. Greater changes in depth can be associated with greater increases in flood risk and in these areas, where this risk cannot be avoided, or land use substituted, mitigation measures are likely to be extensive and for some developments, the FRA may not be able to demonstrate continued safety for occupants as required by the Exception Test.

Climate Change Recommendation

Due to the lack of spatial GIS data available, a Level 2 SFRA should investigate the actual affect of climate change along the River Tyne, Derwent and Team, which should include modelling the most recent climate change predictions available from the Environment Agency. Outputs from this modelling work should include flood extents, to aid the Sequential Test and flood depths to aid the Exceptions Test.

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7 Development & Flood Risk

7.1 Introduction This Level 1 SFRA should assist Gateshead MBC in carrying out the Sequential Test as outlined in the NPPF. The Sequential Test is based on proposed development sites, their situation in regards to flood risk, that level of risk and also the development's vulnerability to that risk. When allocating or approving land for development in flood risk areas, those responsible for making development decisions are expected to demonstrate that there are no suitable alternative development sites located in lower flood risk areas. The SFRA Volume I report provides guidance for Spatial Planners, Development Managers and Developers in how to apply the test and should be referred to the NPPF and the PPS25 Practice Guide. The section below provides a summary of sites assessed in the Level 1 SFRA. One of the main outputs of this assessment is the Flood Risk Screening spreadsheet discussed below.

7.2 Development & Flood Risk Screening

7.2.1 Potential Development Sites Gateshead MBC has provided a number of potential development sites that relate to the Gateshead Core Strategy. These include:  Spatial Strategy Key Development Areas  Retail Centres  Employment Areas  Strategic Land Review Sites

Other site allocations from Making Spaces for Growing Places including SHLAA and ELR have been reviewed separately.

7.2.2 Methodology The initial part of this SFRA flood risk review is to screen all potential development areas/sites identified by Gateshead MBC (not including the SHLAA or ELR as this has been carried out separately) against geographical flood risk data produced in the SFRA, by calculating the area and percentage cover of flood risk zones below:  Flood Zone 3b  Flood Zone 3a  Flood Zone 2  Areas Susceptible to Surface Water Flooding - High  Areas Susceptible to Surface Water Flooding - Intermediate  Areas Susceptible to Surface Water Flooding - Low

The output from this screening method was imported into an Excel spreadsheet (Flood Risk Screening spreadsheet), which can be utilised by Gateshead MBC to apply the Sequential Test. In order to quickly identify the level of flood risk associated with each site, sites have been categorised using colours depending on the results of the screening process. Table 7-1 identifies the criteria used to categories flood risk to each site. The colour coding shows the highest risk element of the flood zone that is present on site and is not in itself an indication of whether the site should or shouldn’t be developed for flooding reason.

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Table 7-1: Potential development site flood risk categories Flood Risk Colour Comment Criteria All sites with a percentage cover of more than 0% in Flood Red Flood Zone 3b Zone 3b. These sites are also likely to be within Flood Zone 3a and 2 and susceptible to surface water flooding All sites with a percentage cover of more than 0% in Flood Orange Flood Zone 3a Zone 3a. These sites are also likely to be within Flood Zone 2 and susceptible to surface water flooding All sites with a percentage cover of more than 0% in Flood Yellow Flood Zone 2 Zone 2. These sites are also likely to be susceptible to surface water flooding Flood Zone 1 and All sites outside of the Environment Agency Flood Map Blue at surface water (Flood Zone 1) but are susceptible to surface water flooding risk All sites outside of the Environment Agency Flood Map White Flood Zone 1 (Flood Zone 1) and not susceptible to surface water flooding

7.2.3 Flood Risk Screening Results Table 7-2 provides a count of the number of potential development sites within the NPPF Flood Zones 1, 2, 3a and 3b. Each site has been attributed to the highest flood risk zone. Table 7-2: Number of potential development sites at risk

Number of sites partially within... Development Type Number of Site FZ1 FZ2 FZ3a FZ3b (100%) Spatial Strategy Key Areas 15 6 1 4 4 Retail Centres 3 2 1 0 0 Employment Areas 15 6 2 4 3 Strategic Land Review Sites 20 20 0 0 0 Total 53 34 4 8 7

Table 7-3 provides a detailed breakdown of the 19 sites identified as high to medium risk of flooding (Flood Zone 3b, 3a and 2). The complete of list of development sites and their flood risk screening results can be found in Appendix E. Table 7-3: Summary of potential development sites at risk

Area Percentage Cover (%) Development Name Development Type (ha) FZ1 FZ2 FZ3a FZ3b Gateshead Quays Spatial Strategy Key Areas 15 93 7 0 0 Metro Green Spatial Strategy Key Areas 179 82 10 7 1 Follingsby Spatial Strategy Key Areas 86 98 0 0 2 Bensham & Saltwell Spatial Strategy Key Areas 238 99 1 0 0 Dunston Spatial Strategy Key Areas 197 85 4 11 0 Felling Spatial Strategy Key Areas 227 99 0 1 0 TVTE Spatial Strategy Key Areas 276 90 8 2 0 Birtley Spatial Strategy Key Areas 650 96 1 2 1 Blaydon Spatial Strategy Key Areas 16 99 0 1 0 Ravensworth Road Retail Centres 1 83 17 0 0

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Area Percentage Cover (%) Development Name Development Type (ha) FZ1 FZ2 FZ3a FZ3b East Gateshead Employment Areas 74 98 2 1 0 Follingsby Employment Areas 46 98 0 0 2 Team Valley Employment Areas 276 90 8 2 0 Sands Employment Areas 1 1 99 0 0 Town Centre Employment Areas 107 98 2 0 0 Blaydon / Employment Areas 97 87 10 3 0 Derwenthaugh Felling Employment Areas 85 99 1 0 0 Durham Road Employment Areas 91 71 8 21 0 Teams Employment Areas 17 72 3 25 0

The Council should use the spreadsheet to identify sites that should be avoided during the Sequential Test. It can also be used to assess whether or not employment and housing projections can be met by purely allocating sites in areas at low risk of flooding. If this is not the case, or where wider strategic objectives require regeneration in areas already at risk of flooding, then the Council should consider the compatibility of vulnerability classifications and Flood Zones and whether or not the Exception Test will be required before allocating sites. In this case, the decision making process should be transparent and information from this SFRA should be used to justify decisions to allocate land in areas at high risk of flooding.

Sequential Test Recommendation

Gateshead MBC should use the flood risk datasets and screening spreadsheet and guidance provided in Volume I of this SFRA to undertaken the Sequential Test for development sites proposed. The Council should also use this information to identify those sites that will require the Exception Test to be passed if allocated.

7.3 Detailed Development & Flood Risk Review In those circumstances where there is an overriding strategic need for development in high risk areas, at a strategic level, Gateshead MBC should consider the likelihood of sites passing the Exception Test before allocating them within the Local Plan. To aid this strategic process, flood risk review tables have been produced to assess the level of risk from all sources of flooding to each site at high risk of flooding. These tables should further guide Gateshead MBC during the Sequential and Exception Test, as well as help identify those sites which could remain safe if developed and flood risks mitigated. For those sites where flood risk is considered too great, development should be avoided during the Sequential Test. Where the flood risk review table suggest flood risk could be managed either through the sequential approach to development or sustainable mitigation measures, development can be allocated as long as they meet the wider requirements of the NPPF i.e. pass the Exception Test.

7.3.1 Flood Risk Review Tables All flood risk review tables are provided on the following information: Flood Risk Present All sources of flood risk are identified using the information provided in this SFRA. It must be noted that any flood levels quoted have been extracted from previously flood mapping studies provided by the Environment Agency for the Level 1 SFRA. Any site specific FRAs should

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investigate these further, which may involve hydraulic model improvements and hydrology calculations. SuDS Recommendations Soil types and SuDS recommendations have also been carried out at a strategic level. Any FRA will have to carry out site specific investigations on the suitability of SuDS. However, it is recommended that this is considered at an early stage in the development process as considerable land take may be required, impacting on achievable yields. It is also important that NWL are consulted at an early stage especially for those sites situated within CDAs or have been identified as having surface water or historical flood issues. Connecting surface water drains to the current system may not be a desirable option and alternatives such as SuDS might have to be considered. Mitigation Recommendations Mitigation recommendations have been made at a strategic level using information contained within this SFRA. It is important to note that although mitigation measures have been discussed for individual sites, it does not mean they have been assessed to show that they do not increase flood risk elsewhere. Any FRA should carry out these investigations and compare a range of techniques. It must also be kept in mind that strategically planned development has the potential to reduce flood risk to the wider community rather than just within the boundaries of the individual site. The most appropriate mitigation solution may be located outside of the site boundary and collective support by other proposed developments may be required. This has been highlighted in the flood risk review tables where possible. A piecemeal approach to development is not desirable where individual development sites focus on their flood risk issues, applying a range of techniques, which may not fit with the wider vision of the community.

Exception Test Recommendation

Gateshead MBC should use the information provided in the review tables below to identify the likelihood of those key sites at high flood risk passing the Exception Test. If current information identifies the level of risk is too high when consider all sources, the sites should be avoided during a second pass of the Sequential Test. If these sites are still required, they should be investigated further during a Level 2 SFRA in which detailed flood risk information is required to support their allocation and development.

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Site Gateshead Quays Spatial Strategy Key Development Area Area 15.33ha Catchment River Tyne Development Type Spatial Strategy Key Areas - Mixed use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b Flood Zones 93% 7% 0% 0% During the 1 in 200-year tidal event, peak levels are predicted to increase from Strategic Climate 4.07mAOD to 4.93mAOD along this reach over the next 100 years. The Change Sensitivity topography of the land rises steep towards the town centre. Any areas at risk will be adjacent to the riverside. Less Intermediate More AStSWF 9% 1% 0% There are little historic flooding records within this site apart from a number of Historical Flood internal flooding incidents collected from the TWFRS. Gateshead MBC has Data recorded flooding along Askew Road from the highways drain Groundwater & The site is within the Kibblesworth and Chaterhaugh Blocks. There have been Mine Water no springs, issues or potential groundwater/mine water discharge points Flooding identified. Northumbrian Water The site is within the Central Gateshead and Gateshead West drainage areas. Drainage Area Neither has been classified as a CDA. Defended There are no official flood defence along the Tyne, rather raised quay walls. Flood Warning No The area is a mix between freely drained slightly acid loamy soils and slowly Generic Soils Type permeable seasonally wet soils. The majority of this area is urban inform with and SUDS drainage reliant on the current drainage system. Drainage could be improved Suitability by controlling and reduce surface runoff rates where possible. All development should be set back from the river frontage to reduce risk. Current risk could increase with climate change. However, the area at risk is unlikely to change significantly, as it will be constrained by topography. There is also a low risk of flooding from other sources. The level and condition of the Exception Test quay wall will be critical along this reach. Any development should apply a Requirement consistent wall level to any future improvements. This should be placed above

the desired climate change level and include freeboard. Any FRA should FRA and Strategic investigate the actual risk associated with of other sources of flooding, Mitigation Options including surface water and flooding from the drainage system. For further information refer to Level 2 SFRA, Gateshead Quays Wall Condition Survey and Climate Change Adaptation Strategy and Surface Water Management Plan.

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Site MetroGreen Spatial Strategy Key Development Area Area 179ha Catchment River Tyne/Derwent Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b Flood Zones 82% 10% 7% 1% During the 1 in 200-year tidal event, peak levels along the Tyne are predicted Strategic Climate to increase from 4.10mAOD to 4.95mAOD over the next 100 years. As a Change Sensitivity result, flood extents and depths are expected to increase significantly. The west side of the site will also be at risk from fluvial increases. Less Intermediate More AStSWF 14% 16% 4% Historical Flood There are only two historical flood records in this area from fluvial and sewer Data sources both located along Cross Lane. Groundwater & The site is within the Kibblesworth Block. There have been no springs, issues Mine Water Flooding or potential groundwater/mine water discharge points identified MetroGreen is within the Dunston Hill CDA. The site is also within the Northumbrian Water Whickham South and Sunniside Drainage Areas however they have a lower Drainage Area risk associated with them. Defended There are no official flood defence along the Tyne, rather raised banks. Environment Agency Flood Warning Area 121FWT549, 121FWT550 and Flood Warning 121FWT551. Freely drained floodplain soils. Due to the scale of the site, it will be a good opportunity to open up development where key flow paths or low-lying areas Generic Soils Type have been identified and incorporate SuDS storage techniques. These will and SUDS Suitability help reduce conveyance, channel floodwater and reducing the level of flood risk. Due to the extent of risk in this area, it would be difficult to avoid and as such, it will be likely that all development within this area will have to apply the Exception Test. A detailed FRA should be produced to pass Part B. It is recommended that the risk to this site is considered strategically as the most Exception Test appropriate mitigation option could be located off site. Any mitigation should be Requirement designed to protect the site up to the 1 in 200-year tidal event including climate change. Flood resilient and resistance measures should be adopted to reduce FRA and Strategic any remaining risk during the 1 in 1000-year event or residual risks if mitigation Mitigation Options includes defences. A greater understanding of flood depths and flow routes will be required, as any development along the bank of the Tyne could become cut off by flow routes to the south. Access and egress could be a major issue to certain sections of the site. For further information refer to Level 2 SFRA, MetroGreen Flood Management Plan and Surface Water Management Plan.

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Site Follingsby Spatial Strategy Key Development Area Area 86ha Catchment River Don Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b Flood Zones 98% 0% 0% 2% Strategic Climate This site is relatively insensitive to climate change impacts on fluvial flows. Change Sensitivity Less Intermediate More AStSWF 9% 4% 1% Historical Flood The site is within the Chaterhaugh Block. There have been no springs, issues Data or potential groundwater/mine water discharge points identified. Groundwater & This site is within the Leam Lane CDA Mine Water Flooding Northumbrian Water There is no history of flooding recorded on or within 50m of this site Drainage Area Defended No Flood Warning No Slow permeable, seasonally wet, basic loams and clay soils. This site is currently agricultural land and has not been developed before. Surface water Generic Soils Type runoff should therefore be reduced to greenfield runoff rates where possible and SUDS Suitability and controlled on site through a sustainable drainage approach (SuDS). Any FRA should consult with NWL before connecting surface water drains to the current drainage network. Parts of the southern boundary of the site, along the River Don, are within Flood Zone 3b and should be removed from the development site, as not development would be permitted. The immediate floodplain of the Don should Exception Test be avoided wherever possible. Consideration should also be given to the Requirement impact of climate change on flood extents, which should be factored into the sequential approach to site layout. There are a number of strong surface water FRA and Strategic flow paths along the east boundary of the site, which must be investigated Mitigation Options further in any site specific FRA. Due to the amount of open space (currently undeveloped) special attention should be given to the application of SuDS to reduce surface water runoff and increase storage on site. Further information refer to SuDS Suitability and Viability Assessment.

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Site Bensham and Saltwell Spatial Strategy Key Development Area Area 238ha Catchment River Tyne/Team Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b Flood Zones 99% <1% 0% 0% Strategic Climate This site is relatively insensitive to climate change impacts on fluvial flows. Change Sensitivity Less Intermediate More AStSWF 4% 2% 1% There are a number of historical flood incidents within this area. One along the Historical Flood River Team associated with main river flooding and a further five relating to Data sewer and surface water flooding. Three of these are clustered around Queens Court. Groundwater & The area is within the Kibblesworth Block. There have been no springs, issues Mine Water Flooding or potential groundwater/mine water discharge points identified. Northumbrian Water This area is within the Team Valley and Bensham Drainage Areas both of Drainage Area which have been classified as CDAs. Defended No Flood Warning Environment Agency Flood Warning Area 121FWT551 Freely drained floodplain soils & slowly permeable seasonally wet acid loamy and clayey soils. Due to the location of the site along the Team and within a Generic Soils Type CDA, SuDS techniques should focus on storage of surface water runoff. and SUDS Suitability Infiltration is not suitable due to the historic use of the site. The adoption and design of SuDS should be investigated further during an appropriate FRA. All development within this area should avoid the natural floodplain of the River Team. The main risk in this area is from surface water flooding and the Exception Test potential capacity issues with the urban drainage network, which will also Requirement contribute to risk along the Team. All development should focus on reducing surface water runoff where possible FRA and Strategic and include the application of SuDS. Limiting the volume of surface water Mitigation Options runoff entering the drainage systems will also reduce additional volume entering the River Team. Surface water drainage could also become tidal locked during high water levels in the Team.

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Site Dunston Spatial Strategy Key Development Area Area 197ha Catchment River Tyne/Team Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 85% 4% 11% 0% During the 1 in 200-year tidal event, peak levels along the Tyne are predicted Strategic Climate to increase from 4.10mAOD to 4.95mAOD over the next 100 years. During the Change Sensitivity 1 in 100-year fluvial event, flood levels are predicted increase by around 0.5m over the next 100-years Less Intermediate More AStSWF 7% 9% 3% There are a number of historical flood incidents within this area, all of which are Historical Flooding related to surface water, sewers, and main river flood interacting. The majority Data of these incidents are located along or near to Ravensworth Road. The area is within the Kibblesworth Block. There are a number of springs, Groundwater & issues or potential groundwater/mine water discharge points identified in this Mine Water Flooding area. The area falls over a number of drainage areas including Dunston, Teams, NWL Drainage Area Team Valley and Lobley Hill. All of which have been classified as CDAs. There are no official flood defence along the Tyne or Team, rather raised Defended banks. Environment Agency Flood Warning Area 121FWT549, 121FWT550 and Flood Warning 121FWT551 Freely drained floodplain soils & slowly permeable seasonally wet acid loamy and clayey soils. Due to the location of the site along the Team and within a Generic Soils Type CDA, SuDS techniques should focus on storage of surface water runoff. & SuDS Suitability Infiltration is not suitable due to the historic use of the site. The adoption and design of SuDS should be investigated further during an appropriate FRA. All development within this area should avoid the natural floodplain of the River Tyne and Team. There are multiple sources of risk in this area including fluvial, tidal, surface water, sewers and groundwater. Any site specific FRA should assess all sources. The Environment Agency has identified a number of Exception Test potential flood mitigation options along the Team to reduce risk, especially to Requirement / FRA Ravensworth Road, which should be considered within the FRA. All & Strategic development should focus on reducing surface water runoff where possible and Mitigation Options include the application of SuDS. Limiting the volume of surface water runoff entering the drainage systems will also reduce additional volume entering the River Team. Surface water drainage could also become tidal locked during high water levels in the Team. For further information refer to Level 2 SFRA and Surface Water Management Plan.

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Site Felling Spatial Strategy Key Development Area / Employment Area Area 227ha Catchment River Tyne Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 99% 0% 1% 0% During the 1 in 200-year tidal event, peak levels are predicted to increase from Strategic Climate 4.07mAOD to 4.93mAOD over the next 100 years. The topography of the land Change Sensitivity rises steep towards the town centre. Any areas at risk will be adjacent to the riverside. Less Intermediate More AStSWF 13% 5% 1% Historical Flooding There are two incidents of sewer flooding in this area located near Old Fold. Data Groundwater & The site is within the Chaterhaugh Blocks. There have been no springs, issues Mine Water Flooding or potential groundwater/mine water discharge points identified. The site is within the Friars Goose and Felling drainage areas. The Felling NWL Drainage Area drainage areas has classified as a CDA. Defended There are no official flood defence along the Tyne, rather banks Flood Warning No The area is a mix between freely drained slightly acid loamy soils and slowly permeable seasonally wet soils. The majority of this area is urban inform with Generic Soils Type drainage reliant on the current drainage system. There would be little benefit & SuDS Suitability from wide scale SuDS adoption. However drainage could be improved by controlling and reduce surface runoff rates where possible. There is less than 1% of this area within Flood Zone 3a. All development should be set back from the river frontage to reduce risk. Current risk could increase with climate change. However, the area at risk is unlikely to change Exception Test significantly, as it will be constrained by topography. Requirement / FRA There are a number of strong surface water flow paths, which should be & Strategic considered during any site specific FRA. Any FRA should investigate the Mitigation Options actual risk associated with of other sources of flooding, including surface water and flooding from the drainage system. For further information refer to Surface Water Management Plan.

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Site Team Valley Spatial Strategy Key Development Area / Employment Area Area 276ha Catchment River Team Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 90% 8% 2% 0% Strategic Climate During the 1 in 100-year fluvial event, water levels along the Team are Change Sensitivity predicted to increase by around 0.5m over the next 100 years. Less Intermediate More AStSWF 26% 20% 2% There are a number of historical flood incidents in the team valley. These are Historical Flooding mainly located along the mains rivers and ordinary watercourses flowing into Data the area. Groundwater & The site is situated within the Kibblesworth Block. There have been no springs, Mine Water Flooding issues or potential groundwater/mine water discharge points identified. NWL Drainage Area The site is situated within the Team Valley CDA. Defended There are no formal defences along the River Team. Flood Warning No Slow permeable, seasonally wet, clayey soils with slow infiltration rates. This area is currently developed so any surface water drainage could connect Generic Soils Type to the current drainage system. However, the site is situated within a CDA & SuDS Suitability therefore the current drainage system may need improving or alternative connections sought such as SuDS. Any FRA should consult with NWL before connecting surface water drains to the current drainage network. Whilst only around 2% of the total site is within Flood Zone 3a, there is a significant risk from flooding from other sources in the area including, ordinary watercourse, surface water and sewers. There is currently little detailed understanding of this combined risk, which should be tackled in order to make Exception Test more informed planning decisions. Requirement / FRA Whilst the majority of the area is currently heavily developed, and regeneration & Strategic should be like for like with the possibility of strategic green open space which is Mitigation Options connected the green infrastructure and potential flood storage. Upstream surface water storage during exceedance events will also be important within any development outside of the Team Valley. For further information refer to Team Valley Integrated Flood Risk Study.

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Site Birtley Spatial Strategy Key Development Area Area 650ha Catchment River Team Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 96% 1% 2% 1% Strategic Climate During the 1 in 100-year fluvial event, water levels along the Team are Change Sensitivity predicted to increase by around 0.5m over the next 100 years. Less Intermediate More AStSWF 11% 7% 1% There are a number of historical flood incidents in Birtley. These are mainly Historical Flooding located along surface water flow paths and are associated with surface water Data or sewer flooding. The area is within the Kibblesworth and Chaterhaugh Blocks. There have been Groundwater & no springs, issues or potential groundwater/mine water discharge points Mine Water Flooding identified. NWL Drainage Area The area is situated within the Birtley CDA. Defended There are no formal defences along the River Team. Flood Warning No Slowly permeable seasonally wet slightly acid but base-rich loamy and clayey soils. The natural soil types would impede any natural drainage therefore any Generic Soils Type SUDS should focus on storage and slowing down runoff rates. The site is at & SuDS Suitability significant risk from surface water flooding. Surface water runoff should be reduced as much and controlled as near to its source as possible through a sustainable drainage approach to surface water management (SuDS). Only the western side of Birtley is at risk from fluvial flooding from the River Team. This equates to around 2% of the total area within Flood Zone 3a. Future development should be avoided in all floodplain areas. Exception Test Birtely is at high risk from surface water and sewer flooding and as such has Requirement / FRA been classified as a CDA. There are a number of significant surface water flow & Strategic routes, with previous historical flooding incidents, which should be considered Mitigation Options during any development. Any FRA should investigate the actual risk associated with of other sources of flooding, including surface water and flooding from the drainage system. For further information refer to Surface Water Management Plan.

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Site Blaydon Spatial Strategy Key Development Area / Employment Area Area 16ha Catchment River Tyne Development Type Spatial Strategy Key Areas - Mixed Use

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 99% 0% 1% 0% During the 1 in 200-year tidal event, peak levels are predicted to increase from Strategic Climate 4.09mAOD to 4.92mAOD over the next 100 years. Due to the height of the Change Sensitivity banks and railway line beyond this, the town centre is relatively insensitive to this change in tidal levels. Less Intermediate More AStSWF 16% 21% 2% Historical Flooding There are two historic flood incidents within this area due to a blocked culvert Data along Blaydon Burn at the New Inn. Groundwater & The area is located near a spring/Issues located along the downstream extent of Mine Water Blaydon Burn Flooding The area is situated within Blaydon West and Blaydon East Drainage Areas with NWL Drainage a medium and low flood risk respectively. Blaydon West has been classified as a Area CDA Defended No. Blaydon Burn is culverted through this site Flood Warning No The area is a mix between freely drained slightly acid sandy soils and slowly permeable seasonally wet acid loamy and clayey soils. The site is highly susceptible to surface water runoff originating outside of the site down Blaydon Generic Soils Type Bank and Shibdon Dene. SuDS should be adopted along these flow routes to & SuDS Suitability control and store surface water reducing risk to the northern area of the site. An improvement in the current drainage maybe required to reduce risk further. The adoption and design of SuDS should be investigated further during an appropriate FRA. Only the northern border of this area is within Flood Zone 3a and would be required to pass the Exception Test if allocated for residential development. The remaining area is mainly at risk from surface water flooding originating off Exception Test site. There are three main surface water flow paths entering the site from the Requirement / south, with water pooling along the A695 and railway embankment. There is also FRA & Strategic a potential risk from Blaydon Burn, which is culverted to the west of the area. Mitigation Options Currently the true extent of risk from this watercourse is unknown. The control of surface water through the use of SuDS and making sure there is drainage into the Tyne will be important to reduce risk to this site. For further information refer to Surface Water Management Plan.

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Site Ravensworth Road Retail Centre Area 2.69 ha Catchment River Team Development Type Growth Point – residential and employment - More vulnerable

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 83% 17% 0% 0% This site is expected to be relatively insensitive to climate change. If flood risk Strategic Climate is not mitigated, tidal Flood Zone 3 could progress into the northern area of the Change Sensitivity site but this is expected to be low coverage Low Medium High AStSWF 14% 23% 0% Historical Flooding Flooding from NWL drainage system November 2000 Data Groundwater & The site is situated with the Kibblesworth Block. There have been no springs, Mine Water Flooding issues or potential groundwater/minewater discharge points identified NWL Drainage Area The site is situated within the Dunston and Lobby Hill CDA Defended No Flood Warning Environment Agency Flood Warning Area 121FWT549 and 121FWT551. Freely drained floodplain soils & slowly permeable seasonally wet acid loamy and clayey soils. Due to the urban nature of this site and its location within a Generic Soils Type CDA, SuDS techniques should focus on storage and the reduction of surface & SuDS Suitability water runoff. The adoption and design of SuDS should be investigated further during an appropriate FRA. This site is situated within Flood Zone 2 and therefore the Exception Test is not required. There is also a risk from surface water flooding and flooding from the current drainage system. These issues should be considered during a site- specific FRA. There is a high likelihood that this site could remain safe from flooding however any development should be focused to Flood Zone 1 areas. Tidal flood risk could be mitigated through land raising on site, however opportunities should Exception Test be sought to stop flood water entering the left-hand floodplain from the River Requirement / FRA Team through techniques closer to the source. By doing so, risk could be & Strategic reduced to the wider community. Mitigation Options There is safe access to the site from multiple entries to the south and west sides. Surface water runoff should be reduced as much as possible from the site as there are significant surface water risk surround Festival Way and historical surface water records along the intersection between Ravensworth Road and Seymour Street. Runoff should be controlled as near to its source as possible through a sustainable drainage approach to surface water management (SuDS).

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Site Gateshead Town Centre and Gateshead East Employment Areas Area 181ha Catchment River Tyne Development Type Primary Employment Areas

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 98% 2% 0% 0% During the 1 in 200-year tidal event, peak levels are predicted to increase from Strategic Climate 4.07mAOD to 4.93mAOD over the next 100 years. The topography of the land Change Sensitivity rises steep towards the town centre. Any areas at risk will be adjacent to the riverside. Less Intermediate More AStSWF 11% 2% <1% There are little historic flooding records within this site apart from a number of Historical Flooding internal flooding incidents collected from the TWFRS. Gateshead MBC has Data recorded flooding along Askew Road from the highways drain Groundwater & The site is within the Kibblesworth and Chaterhaugh Blocks. There have been Mine Water no springs, issues or potential groundwater/mine water discharge points Flooding identified. NWL Drainage The site is within the Central Gateshead and Gateshead West drainage areas. Area Neither has been classified as a CDA Defended There are no official flood defence along the Tyne, rather raised quay walls. Flood Warning No The area is a mix between freely drained slightly acid loamy soils and slowly Generic Soils Type permeable seasonally wet soils. The majority of this area is urban in form with & SuDS Suitability drainage reliant on the current drainage system. Drainage could be improved by controlling and reduce surface runoff rates where possible. There is less than 1% of this area within Flood Zone 3a. All development should be set back from the river frontage to reduce risk. Current risk could increase with climate change. However, the area at risk is unlikely to change significantly, as it will be constrained by topography. Any development should apply a Exception Test consistent wall level to any future improvements. This should be placed above Requirement / the desired climate change level and include freeboard. There are a number of FRA & Strategic strong surface water flow paths in Gateshead East which should be considered Mitigation Options during any site specific FRA. Any FRA should investigate the actual risk associated with of other sources of flooding, including surface water and flooding from the drainage system. For further information refer to Level 2 SFRA, Gateshead Quays Wall Condition Survey and Climate Change Adaptation Strategy and Surface Water Management Plan.

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Site Teams Primary Employment Area Area 9ha Catchment River Tyne/Team Development Type Primary Employment Area - Less Vulnerable

© Crown copyright and database rights 2013 Ordnance Survey Gateshead Council 100019132 Flood Zone 1 Flood Zone 2 Flood Zone 3a Flood Zone 3b NPPF Flood Zone 72% 3% 25% 0% During the 1 in 200-year tidal event, peak levels along the Tyne are predicted Strategic Climate to increase from 4.10mAOD to 4.95mAOD over the next 100 years. During the Change Sensitivity 1 in 100-year fluvial event, flood levels are predicted increase by around 0.5m over the next 100-years Less Intermediate More AStSWF 7% 9% 3% There are a number of historical flood incidents within this area, all of which are Historical Flooding related to surface water, sewers, and main river flood interacting. The majority Data of these incidents are located along or near to Ravensworth Road. Groundwater & The area is within the Kibblesworth Block. There are no springs, issues or Mine Water Flooding potential groundwater/mine water discharge points identified in this area. NWL Drainage Area The area falls within the Teams Valley CDA. There are no official flood defence along the Tyne or Team, rather raised Defended banks. Environment Agency Flood Warning Area 121FWT549, 121FWT550 and Flood Warning 121FWT551 Freely drained floodplain soils & slowly permeable seasonally wet acid loamy and clayey soils. Due to the location of the site along the Team and within a Generic Soils Type CDA, SuDS techniques should focus on storage of surface water runoff. & SuDS Suitability Infiltration is not suitable due to the historic use of the site. The adoption and design of SuDS should be investigated further during an appropriate FRA. The main source of risk is fluvial and tidal flooding along the River Team. 25% of the site is within Flood Zone 3a. All development within this area should be avoid during the Sequential Test. All development should be placed back away Exception Test from the river frontage towards the northeast corner. The area is also at risk Requirement / FRA from surface water flooding which pools in the natural floodplain of the Team. & Strategic Surface water drainage into the Team could be prone to tidal locking. Mitigation Options The Environment Agency has identified a number of potential flood mitigation options along the Team to reduce risk, especially to Ravensworth Road, which should be considered within the FRA.

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7.4 Additional Potential Development Sites As part of the production of the new joint planning framework – ‘One Core Strategy NewcastleGateshead 2030', Gateshead MBC have undertaken a Strategic Housing Land Availability Assessment (SHLAA) and Employment Land Review (ELR). JBA undertook two separate flood risk reviews, screening potential housing and employment sites against the flood risk datasets provided in this SFRA. These reviews followed the same process used in Sections 7.2 and 7.3. The result can be found in the following documents: 1. Gateshead MBC (2013) Employment Land Review Flood Risk Review 2. Gateshead MBC (2013) Strategic Housing Land Availability Assessment Flood Risk Review

7.4.1 SLR Flood Risk Screening According to Gateshead MBC, neither the SHLAA nor ELR identify enough land to meet the Council's expected needs over the Plan period (up to 2030). Gateshead MBC therefore undertook a Strategic Land Review (SLR) to establish how much – and which – land is required to meet their needs. The SLR covers potential new housing sites to meet the needs of a growing population, which cannot be met from existing available land. Gateshead MBC has identified twenty one SLR sites for residential and industrial development; twenty sites have been highlighted for residential use and one for industrial use. Whilst none of the housing sites are located in flood zone (2 and 3), as part of the Council's commitment to sustainable development and as an emerging Sustainable Drainage Systems Approval Body (SAB), the Council have identified the need to assess SuDS constraints and opportunities at each site. Gateshead MBC appointed JBA in 2013 to undertake a SuDS viability assessment for each site. As part of this assessment, JBA reviewed flood risks. The key flood risk findings have been extracted and summarised below, whilst the results of the flood risk screening can be found in the Flood Risk Screening spreadsheet. The plans illustrate areas Susceptible to Surface Water flooding. Development of the SLR sites should maintain at least greenfield runoff rates up to at least a 1 in 100 year storm event, considering climate change.

Site 288 and 292 Crawcrook South Areas of site 288 may be susceptible to surface water flooding. A surface water flow path is shown going across the site from the A695 to the entrance of Bracken Way, and would suggest that this part of the site and the area east of Kepier Chare and below may be at risk of pluvial flooding. This surface water flow path will need to be maintained, as blocking it could create flooding elsewhere. There is an opportunity to intercept some of this surface water runoff to prevent it reaching properties on Bracken Way and Keeper Chare by integrating additional storage into the SuDS; although this could increase the footprint of the SuDS, there may be gains for both developer and council. An overland flow path has been identified to the east of site 292 and appears to be connected to flows arising from Crawcrook village to the south; areas of potential ponding have also been identified. This surface water flow path will need to be maintained, as blocking it could create flooding elsewhere or exacerbate existing conditions. This will have to be considered within the detailed design of the development layout.

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Site 305 Highfield Flood risk analysis has shown no recorded flood events within the site and immediate vicinity. The Environment Agency flood mapping indicates a flow path/area susceptible to surface water flooding from northeast corner of the site onto Highfield Road, topography suggests this runoff is from William Morris Avenue, Wood Lea Road and Hookergate Lane / Smailes Lane B6315; the Northern boundary on the B6315 may be susceptible to surface water flooding; and a small area of ponding midway along the eastern boundary. Development within this area must control surface water runoff with the aim of reducing risk to current residential properties adjacent to the site.

Site 224, 307a and 309 Chopwell There are a number of small ordinary watercourses in the area, which drain into the River Derwent. Flood risk analysis has shown no recorded flood events within the site boundaries or immediate surrounding area. Environment Agency flood mapping does not indicate any areas susceptible to surface water flooding. These sites are not protected by any recorded national defence. There is anecdotal evidence to suggest that problems due to ground water flooding may exist downstream of the sites. Site 307a Environment Agency flood mapping indicates a strong surface overland flow path flowing through the north east of the site with a potential area of ponding on the eastern boundary; flows appear to be surface water runoff from the adjoining fields, and development should avoid these areas. The site is not protected by any recorded national flood defences. These flows may also contribute to flooding further downstream. British Geological Survey (BGS) mapping indicates areas are likely to be affected by persistent shallow ground water. BGS mapping indicates that the northern part of site 224 is affected by a persistently high water table. The north western half of the site is also shown as made ground over relatively impermeable strata. Therefore there remains a possibility of ground water reaching the surface and causing flooding. There is an unnamed watercourse in the vicinity of Site 309, which has potential issues associated with discharging into watercourse/existing culvert downstream at Blackhall Mill. A FRA will have to assess these impacts. BGS mapping indicates areas are likely to be affected by persistent shallow ground water and springs are identified within the surrounding area in the SFRA level 1. The development should also consider overland flow routes to ensure natural flow paths are maintained, and areas of deep water or high velocity are not created within or immediately outside the development, that will prevent access or cause damage to property or infrastructure. Peak flow rate and volumes should be restricted to greenfield rates to ensure runoff from the development does not increase the risk of flooding to areas downstream. Site investigations and/or site specific flood risk assessment should be carried out to determine depths to groundwater and the risks of onsite flooding.

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There may be some scope to provide storage for surface water run-off, in addition to that required for SuDS, to help alleviate flooding at Blackhall Mill; consideration may be given to taking an integrated approach with all sites. However further study would be required to assess the feasibility of doing this. Site 43 and 263 Kibblesworth Coltspool Burn (a tributary to the River Team) lies to the north of the site. No flood zones are available; these are likely to be similar to the surface water zones. Flood risk analysis has shown no recorded flood events within the site boundaries although flooding from various sources has occurred in the Grange Estate and Kibblesworth Bank/The Crescent and from the unnamed watercourse to the east of the site 43 that ultimately discharges to the Coltspool Burn. Environment Agency's flood map for surface water does not indicate vulnerability to surface water flooding. However, the Areas Susceptible to Surface Water Flooding Map indicate a distinct surface water flow path from Ouslaw Lane through site 43 to the Coltspool Burn and from Kibblesworth Bank towards the Grange Estate into an unnamed watercourse, which ultimately discharges into the Coltspool Burn. There are also four small areas of potential ponding in site 43, though development ground works are likely to remove/rework these areas. The site is not protected by any recorded national flood defences. All areas susceptible to surface water flooding should be left as open greenspace or designed to incorporate SuDS. There may be opportunities to help alleviate flooding in the area of Kibblesworth Bank/The Crescent by incorporating overland flows within site control SuDS; although this could increase the footprint of the SuDS, there may be gains for both developer and council. BGS mapping indicates areas of persistent shallow groundwater. A FRA should consider these issues and determine the effects surface water discharge will have on areas downstream. Site 312, 357, 358, 363 and 364 Sunniside Flood risk analysis on site 312 and 364 has shown no recorded flood events within the site boundary or immediate vicinity. Environment Agency flood mapping indicates the site is not susceptible to surface water flooding; nor are there any overland flow paths indicated. There may be limited potential to reduce flood risk downstream, especially if considered with site 364 although further study would be required to assess the viability of this. An ordinary watercourse runs through sites 312 and 354 and work may require consent from Gateshead MBC. Flooding incidents have occurred near site 357, 358 and 363 on nearby Pennyfine Road. Environment Agency flood mapping indicates an area susceptible to surface water flooding to the south west of the site with an overland flow path from the site through the rear gardens of Burdon Lodge and the Birches to the unnamed watercourse to the north of Gateshead Road. In addition there is a culverted water course below the A692, which may have insufficient capacity to convey overland flows. A site specific risk assessment is required to assess the area affected by flooding; this should be combined with sites 358 and 363. The site is not protected by any recorded national defence. There may be an opportunity to alleviate potential flooding in

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the Burdon Park area by integrating additional storage into the SuDS; although this could increase the footprint of the SuDS, there may be gains for both developer and council. A FRA should demonstrate there will be no increase in flood risk downstream along Black Burn and areas susceptible to surface water flooding are avoided. Site 301 and 322 High Spen Areas of potential surface water flooding have been identified at several points along the western boundary of site 301. This will have to be considered within the detailed design of the development layout. The primary runoff destination is likely to be to either Spen Burn via sewer requisition or the Barlow Burn via formalised land drain, however additional on site storage may be required so as not to increase flood risk further downstream. Site 322 neighbouring golf course to the west has been susceptible to groundwater flooding (a spring has been identified in the Level 1 SFRA); on site investigations and/or site specific flood risk assessment should be carried out to determine depths to groundwater and the risks of onsite flooding from this source. Flood risk analysis has shown no recorded flood events within the boundary or immediate surrounding site 322 (within 250m of the site boundary); Environment Agency flood mapping indicates the site is not at risk of flooding nor is it protected by any recorded national defence. Areas susceptible to surface water flooding should be incorporated into green spaces and there may be opportunities to manage surface water flood risk in areas of Collingdon Road, Ramsey Street and Watson Street by providing additional storage within SuDS features. In addition existing surface water sewers to the north of site 301 discharge into the Barlow Burn. These are located along the natural flow paths which may be opened up to form natural channels, increasing capacity and reducing flood risk. Site 62, Site 269 and Site 270a Dunston Hill Flood risk analysis has shown no recorded flood events within the site boundary or immediate vicinity. Environment Agency flood mapping indicates that site 269 is susceptible to surface water flooding at the north east boundary; however there is no indication of any overland flow paths for surface water runoff. The site is not protected by any recorded national flood defences. The development should also consider overland flow routes to ensure natural flow paths are maintained, and areas of deep water or high velocity are not created within or immediately outside the development, that will prevent access or cause damage to property or infrastructure. The sites are located within a contributing natural catchment of the Critical Drainage Area to the north of the B6317. There may be opportunities to help alleviate flooding in the area of Blackburn by incorporating overland flows within site control SuDS; although this could increase the footprint of the SuDS, there may be gains for both developer and council. All surface water will need to be controlled to greenfield levels reducing discharge into the sewer network north or into Black Burn. This should be investigated through a FRA considering the effects surface water discharge will have on areas downstream.

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Site 285 and 287 Ryton Areas of the sites are susceptible to surface water flooding with an overland flow path being identified through the sites allowing surface water runoff from the A695 to flow through site 287 into site 285 to reach Grange View and Grange Drive to the north of the site. A review of the historical flood incident data shows that flooding has occurred at Woodside Lane from the surface water storage pond on two occasions with the wetland reservoir is known to flood from surface water runoff. The north east corner of the sites has some form of land drains which are reported to be constantly wet. Storage of water will be required to limit the post development run-off to greenfield levels. This may be stored in areas such as car parks or landscaping, and disposal may be by infiltration into the ground or into the surface water drainage system at Holburn Dene. Development of this site may offer an opportunity to help alleviate surface water flooding to local areas by attenuating surface water runoff from the A695 on site, preventing flows reaching Grange Drive and into Crookhill. The opportunity to upgrade the existing sewer network may also arise from this development. Development should avoid the flow path along Woodside Lane, and that crossing the site from the A695 to Grange View. South of Follingsby Lane Parts of the southern boundary of the site, along the River Don, are within Flood Zone 3b and development including functional SuDS would not be permitted within this zone. The immediate floodplain of the Don should be avoided wherever possible. A review of the historical flood incident data does not show any recorded incidents. The site is not protected by any recorded national flood defences. There is a strong surface water flow path along the east boundary of the site. This appears to be connected to off-site flow paths arising within the Follingsby Industrial Estate and must be investigated further in a site specific FRA. Overland flow paths originating off-site may be mitigated by implementing green networks within the development. Topographic depressions and valley formations within the central site have been identified as areas susceptible to surface water flooding. This is unlikely to be a constraint to development and should be designed out during the detailed design stage. The BGS data does not indicate any very significant geological hazards within the site. Storage of water will be required to limit the post development runoff to greenfield rates. This may be stored in areas such as car parks, landscaping, swales or ponds.

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8 SFRA Recommendations

8.1 Introduction Since publication of the Pitt Review and the FWMA, it is apparent that SFRAs will provide a central location for data, information and consideration for all flood risk issues relating to flooding from all sources at a local level; and provide the linkage between CFMPs, SMPs, RFRAs, SWMPs and appropriate sustainable land uses over a number of planning cycles. In order to achieve this, Gateshead MBC should take a lead role in flood risk management, continue the work of this Level 1 SFRA, and increase the understanding and information available on flood risk issues. The FWMA defines this responsibility further, identifying Gateshead MBC as a LLFA. There are a number of plans and assessment, which could develop this local understanding of flood risk from all sources with Gateshead, as outlined below.

8.2 Level 2 Strategic Flood Risk Assessment This Level 1 SFRA has provided the evidence base for Gateshead MBC to apply the Sequential Test as set out in the NPPF. Whilst the suite of Flood Risk Maps provided will inform the decision making process and go some way in informing the likelihood of passing the Exception Test, they do not provide the level of detail required to assess whether or not the Exception Test could be passed. The aim of a Level 2 SFRA is to provide this greater understanding of the flood mechanisms and residual risks, concentrating on specific locations (or development sites), and to provide the evidence needed to understand the likelihood that sites will pass Part B) of the Exception Test – whether the development will be safe. Overall, it assesses whether or not sites at flood risk are deliverable in terms of Flood Risk Management (FRM) and that Gateshead MBC understand the full implications of allocating or including these areas in the Local Plan. NPPF and the PPS25 Practice Guide provide the scope for a Level 2 SFRA. It should include the detailed nature of the flood hazard within a flood zone including:  Flood probability,  Flood depth,  Flood velocity  Rate of onset of flooding

The Level 2 SFRA should also provide information on flood defences including their location, SoP, condition and an assessment of defence breaching and overtopping. During consultation of this Level 1 SFRA, the Environment Agency provided a number of recommendations regarding the scope of a Level 2 SFRA, which included assessing: 1. The inaccuracies in Flood Zone 3 on minor watercourses, in particular non-main rivers due to scale and misalignment issues including Blaydon Burn, Urpeth Burn and Black Burn in the Team Valley 2. Residual risks associated with flood defences 3. SuDS suitability and sustainability at a site level

Since the Environment Agency made these draft recommendations, their Flood Risk Mapping Team have been contacted, in which they stated that a flood risk mapping project is being planned on Black Burn and updated Flood Zones should be made available in the future to correct the issue of misalignment. However, these are not high priority internally within the Environment Agency; therefore, they should be considered strategically during a Level 2 SFRA. The scope of the Gateshead Level 2 SFRA should include:  An investigation into the condition of defence infrastructure, including detail investigation into recent and future flood risk management schemes  A review of available hydraulic river models from the Environment Agency

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 The development of a detailed 1D-2D hydraulic models of the Tyne and lower reaches of the Derwent and Team to enable the production of depth, velocity and hazard maps for this key high risk area  Recommendations of realistic mitigation measures available  Further consultation with the Environment Agency and NW on the CDAs proposed in this Level 1 SFRA and using any further information provided to refine the areas. Final CDAs in the Level 2 SFRA should be used to produce detailed recommendations on the control of surface water runoff

The information should focus on those key development sites identified within Section 7.3, which have been identified as requiring the Exception Test. The Level 2 SFRA should provide that next level of information required identifying the likelihood of these sites passing the Exception Test, recommendations for development layout, suitable mitigation techniques and the adoption of SuDS.

8.3 Surface Water Management Plans The Pitt Review, PPS25, Making Space for Water, the FWMA and Surface Water Management Plan (SWMP) guidance recognise the need for clearer roles and responsibilities for different sources of flood risk, with the current legislative framework leading to a fragmented and piecemeal approach for managing urban flood risk. A local leadership role for local flood risk issues has emerged whereby local authorities will be the LLFA and need to have in place a strategy to manage these risks, of which a SWMP is an integral part. Surface water flooding is a major source of flood risk and as demonstrated by the summer 2007 floods can lead to serious flooding of property and possessions. These impacts can be mitigated through the implementation of established ‘best practice’ drainage techniques including Sustainable Drainage Systems (SuDS) at the planning application stage. However, in some circumstances site constraints dictate that a catchment-wide, holistic approach to surface water management is required through urban catchment planning and strategic consideration of the design, construction, maintenance and improvement of sewers and watercourses. Local Authorities need to take a lead role with close liaison between Water Companies and the Environment Agency being essential to ensure a consistent and co-ordinated approach to surface water management and this may be best achieved by the production of appropriate SWMP. SWMPs are developed by a partnership between a Local Authority, Water Company and the Environment Agency. They provide an opportunity to:  Develop a framework for joint working and data sharing (which is a fundamental part of flood risk management under the Flood and Water Management Act)  Collate a central geographic database of drainage assets and flood risk issues  Assess the likelihood of surface water flooding through various modelling approaches  Assess the risk of surface water flooding to people, properties and the environment  Communicate this risk to local communities  Assess the costs and benefits of various flood risk reduction measures  Provide a drainage strategy for areas of significant development if appropriate  Provide a framework for implementation and monitoring of the surface water strategy for a given area

8.3.1 Recommendations for CDAs Future Water (Defra, 2008) sets out the role that SFRAs can have in identifying Critical Drainage Areas (CDAs) for which more detailed surface water management studies can be developed. The Defra SWMP Guidance (2009) supports the use of SFRAs in providing the evidence base for where SWMPs are required. This Level 1 SFRA has identified CDAs based on natural catchments, NWL drainage areas and known flooding problems. The CDAs identified here should be taken as a starting point in the identification of areas for which a SWMP would be beneficial. Where sewer systems are

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interconnected across the boundaries of natural catchments, the additional catchments of the sewers should be taken into account when finalising SWMP boundaries in areas where a high risk of sewer flooding has been identified due to known historic flooding incidents and sewer network is under capacity. The catchments of sewers often encompass more than one local authority. Using the information collated in this SFRA the following recommendations have been made for future surface water management. Table 8-1: CDA recommendations

CDA Recommendation A Drainage Strategy should be undertaken for the neighbourhood to Blaydon West identify the true nature of flood risk from the drainage network and the interactions with Blaydon Burn. A Drainage Strategy should be undertaken for the neighbourhood to identify the true nature of flood risk from the drainage network and the interactions with the River Derwent. The study should also identify areas Derwenthaugh suitable for SuDS, allowable discharges from sites and where surface water flow paths could be opened up in new development. It is important that future development does not increase surface water discharges. A Drainage Strategy should be undertaken for the neighbourhood to identify areas suitable for SuDS, allowable discharges from sites and Felling and Leam where surface water flow paths could be opened up in new development. Lane It is important that future development does not increase surface water discharges. A SWMP should be undertaken for this area that will look in detail at drainage assets and local flood risk and assess feasible options for reducing risk. This may include a drainage strategy for the collection of Dunston, Team development sites to identify areas suitable for SuDS and where surface Valley and water flow paths could be opened up in new development. There will be Bensham significant interaction between the River Team, Black Burn and the underlying drainage network. Large sections of the watercourses are also culverted. It is important that future development does not increase surface water discharges into Black Burn or the River Team. A SWMP should be undertaken for Birtley that will look in detail at drainage assets and local flood risk and assess feasible options for reducing risk. This may include a drainage strategy for the collection of Birtley development sites to identify areas suitable for SuDS and where surface water flow paths could be opened up in new development. It is important that future development does not increase surface water discharges into Rowletch Burn and the River Team.

Gateshead MBC is currently preparing the Newcastle/Gateshead SWMP as a joint evidence base for the joint Core Strategy with Newcastle City Council. The SWMP has currently carried out a risk assessment of key development locations through Gateshead and Newcastle, including strategic surface water modelling, and assessed potential management options. The next stage of the SWMP is to carry out a strategic assessment of surface water across Gateshead as a whole. Recommendations made within this Level 1 SFRA and any Gateshead Level 2 SFRA should inform this process. Until a SWMP has been completed, all developments identified at risk from surface water flooding should adhere to the guidance in PPS25 Practice Guide and the recommendations outlined in this SFRA. Integrated drainage solutions should be prepared for larger sites or areas. Where major flow paths have been identified these should be considered in the master planning of the site and the sequential placement of development. Where available, SuDS techniques should be identified within the development at the earliest possible stage.

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8.4 Water Cycle Studies Water Cycle Studies (WCS) are an all encompassing study of the capacity in water supply, waste water infrastructure and water in the environment, aimed at those regions that are expecting growth. Its main aim is to ensure that new development can be supplied with the required water services it needs in a sustainable way. Over 9000 planned new homes will be built in Gateshead by 2021. To ensure that growth on this scale can be supplied with sufficient water supply and wastewater treatment facilities, without detrimentally affecting the natural water cycle, it is essential to consider the water infrastructure needs as early in the planning process as possible. A WCS will provide Gateshead MBC and development organisations with the necessary planning tool for this purpose and the planning base to support their LDF. Howdon Sewerage Treatment Works (STW) serves parts or all of the local authority areas of Newcastle, Gateshead, North Tyneside, South Tyneside and Northumberland, which drain to Tyneside. Evidence from Newcastle Gateshead Water Cycle Study and from Northumbrian Water Limited identified that Howdon Sewage Treatment Works (STW) presents a potential constraint to growth. It suggests that 7-12 years of planned development within the Howdon catchment can be accommodated if current practice and discharges of surface water into the public sewerage system continue. Headroom cannot be said to be equally available to all parts of the catchment. There are locations where the water and sewerage infrastructure is already at or near capacity, while there are others where trade reductions or moving populations mean that the infrastructure is underused. It may be unlikely that there will be capital investment to improve the sewerage treatment works capacity. NWL will be investing in solutions to remove existing surface water from the public sewerage system, although this will not secure the long term capacity. On this basis the solution to increase capacity may need to be based upon reducing surface water flows into mains sewers through use of SUDS and connections to watercourses. All developers should still use the Pre-Development Enquiry from NW (see Volume I Appendix C) to identify existing and proposed drainage arrangements, connection points and proposed discharge rates for sewerage. For water, this could include an indication of what local network reinforcement the developer could expect to fund.

8.5 Green Infrastructure Framework The Green Infrastructure (GI) of Gateshead is part of the council area’s life support system. It is a planned and managed network of natural environmental components and green spaces that intersperse and connect the urban centres, suburbs and rural fringe. In general, GI consists of:  open spaces – parks, woodlands, nature reserves, lakes  linkages – River corridors and canals, pathways and cycle routes and greenways  networks of “urban green” – private gardens, street trees, verges and green roofs

The identification and planning of GI is critical to sustainable growth. It merits forward planning and investment as much as other socio-economic priorities such as health, transport, education and economic development. GI is also central to climate change action and is recurring theme in planning policy statements, the regional spatial strategy and the sub-regional SFRA. Concerning flood risk, green spaces can be used to manage storm flows and free up water storage capacity in existing infrastructure to reduce risk of damage to urban property, particularly in city centres and vulnerable urban regeneration areas. GI can also improve accessibility to waterways and improve water quality, supporting regeneration and improving opportunities for leisure, the local economy and biodiversity. The SFRA evidence base should be used to enhance any Gateshead Green Infrastructure Study/Strategy/Implementation Plan. River corridors identified as functional floodplain are an excellent linkage of GI and can provide storage during a flood event. Areas identified within the urban environment or upstream of a critical surface water flood areas should be incorporated into Gateshead’s GI strategy. Opening up land to create flow

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paths or flood storage areas can help protect current and future property as long as they are developed in line with the current sewerage system.

8.6 Summary The above Sections have recommended a number of further studies within Gateshead, which could provide the Council with more detailing flood risk information. This ‘extra’ level of detail would help inform the application of the Sequential and Exception Tests and go some way in outlining key FRM policy and mitigation approaches in reducing and controlling flood risk. The table below summaries these Level 1 SFRA recommendations: Table 8-2: Summary of future recommended studies

Study Required Area Timetable This study should be carried out once Gateshead MBC has Key strategic and Growth Point applied the Sequential Test in sites along Tyne and lower line with the LDF process. Level 2 SFRA Yes reach of the River Derwent and This study may be needed to Team inform preparation of the Allocations DPD and Core Strategy of Strategic Sites Dunston, Team Valley, Short term to inform allocation SWMP/WCS Yes Bensham and Birtley of land with the Local Plan Drainage Blaydon West, Derwenthaugh, Yes Long Term Strategy Felling and Leam Lane

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Appendices B Digital Data Register Digital Data Register can be found on the Gateshead MBC Level 1 SFRA Digital Deliverables DVD - Appendix A Folder

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C Historical Flood Incident Register Historical Flood Incident Register can be found on the Gateshead MBC Level 1 SFRA Digital Deliverables DVD - Appendix B Folder

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D Allied Exploration & Geotechnics Ltd Groundwater Review Allied Exploration & Geotechnics Ltd Groundwater Review can be found on the Gateshead MBC Level 1 SFRA Digital Deliverables DVD - Appendix C Folder

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E Flood Risk Screening Spreadsheet The Flood Risk Screening Spreadsheet can be found on the Gateshead MBC Level 1 SFRA Digital Deliverables DVD - Appendix D Folder

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F Glossary of Terms

Terms Definition Attenuation Reduction of peak flow and increased duration of a flow event Breach of A structural failure at a flood defence allowing water to flow through Defences Catchment Flood A strategic planning tool through which the Environment Agency will seek Management Plans to work with other key decision-makers within a river catchment to (CFMP) identify and agree policies for sustainable flood risk management Long-term variations in global temperatures and weather patterns, both Climate Change natural and as a result of human activity Health, social, economic and environmental effects of flooding, of flooding, some of which can be assessed in monetary terms, while other Consequence of less tangible impacts are more difficult to quantify. Consequences flooding depend on the hazards associated with the flooding and the vulnerability of receptors Compensation A floodplain area introduced to compensate for the loss of storage as a storage result of land raising for development purposes When a river overflows its banks, it continues to flow over the floodplain, Conveyance conveying water down-stream, as well as storing water where the flood[lain may be obstructed and releasing it slowly A historic or notional flood event of a given annual flood probability, Design event against which the suitability of a proposed development is assessed and mitigation measures, if any, are designed Design flood level The maximum estimated water level during the design event Register held by water companies on the location of properties at risk of DG5 register sewage related flooding problems Flood ‘zone’ maps released by the Environment Agency to depict Extreme Flood anticipated 0.1% (1 in 1000 year) flood extents in a consistent manner Outline throughout the UK Flooding is the overflowing of water onto land that is normally dry. It may be caused by overtopping of breach of banks or defences, inadequate or Flooding (or slow drainage of rainfall, underlying groundwater levels or blocked drains inundation) and sewers. It presents a risk only when people, human assets and ecosystems are present in the areas that flood Flood Alleviation A scheme designed to reduce the risk of flooding at a specific location Scheme (FAS) Flood defence infrastructure, such as flood walls and embankments, Flood defence intended to protect an area against flooding to a specified standard of protection This occurs when flow entering a system, such as an urban storm water Flooding from drainage system, exceeds its discharge capacity, becomes blocked or Artificial drainage when the system cannot discharge due to a high water level in the systems receiving watercourse The features of flooding which have harmful impacts on people, property Flood Hazard or the environment (such as the depth of water, speed of flow, rate of onset, duration, water quality etc) A map produced by the Environment Agency providing an indication of Flood Map the likelihood of flooding within all areas of England and Wales, assuming there are no flood defences. Only covers river and sea flooding

Floodplain Area of land that borders a watercourse, an estuary or the sea, over which water flows in time of flood, or would flow but for the presence of

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Terms Definition flood defences where they exist An expression of the combination of the flood probability or likelihood and Flood Risk the magnitude of the potential consequences of the flood event A study to assess the risk to an area or site from flooding, now and in the future, and to assess the impact that any changes or development on the site or area will have on flood risk to the site and elsewhere. It may also Flood Risk identify, particularly at more local levels, how to manage those changes Assessment (FRA) to ensure that flood risk is not increased. PPS25 Practice Guide differentiates between regional, sub-regional/strategic and site- specific flood risk assessments Flood Risk The introduction of mitigation measures (or options) to reduce the risk Management posed to property and life as a result of flooding. It is not just the (FRM) application of physical flood defence measures Flood risk management Any measure which reduces flood risk such as flood defences measure Flood risk A long-term approach setting out the objectives and options for management managing flood risk, taking into account a broad range of technical, strategy social, environmental and economic issues The temporary storage of excess runoff or river flow in ponds, basins, Flood Storage reservoirs or on the floodplain A geographic area within which the flood risk is in a particular range, as Flood Zone defined within the NPPF. Fluvial Flooding caused by overtopping of rivers or stream banks The difference between the flood defence level and the design flood Freeboard level, which includes a safety margin for residual uncertainties A map that delineates the areas estimated to be at risk of flooding during Indicative an event of specified flood probability. Being indicative, such maps only Floodplain Map give an indication of the areas at risk but, due to the scale and (IFM) complexity of the exercise, cannot be relied upon to give precise information in relation to individual sites ISIS is a software package used for 1-Dimensional river modelling. It is ISIS used as an analysis tool for flood risk mapping, flood forecasting and other aspects of flood risk management analysis A general concept relating to the chance of an event occurring. Likelihood is generally expressed as a probability or a frequency of a flood of a given magnitude or severity occurring or being exceeded in Likelihood any given year. It is based on the average frequency estimated, (probability) of measured or extrapolated from records over a large number of years and flooding is usually expressed as the chance of a particular flood level being exceeded in any one year. For example, a 1 in 100 or 1% flood is that which would, on average, be expected to occur once in 100 years, though it could happen at any time A non-statutory term used to describe a folder of documents which includes all the local planning authority’s Local Development Documents Local Development (LDDs). The local development framework will also comprise the Framework (LDF) statement of community involvement, the local development scheme and the annual monitoring report All development plan documents which will form part of the statutory Local Development (LDDs) development plan, as well as supplementary planning documents Documents (LDD) which do not form part of the statutory development plan Ordinary All rivers, streams, ditches, drains, cuts, dykes, sluices, sewers (other

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Terms Definition watercourse than public sewer) and passages through which water flows which do not form part of a Main River. Local authorities and, where relevant, Internal Drainage Boards have similar permissive powers on ordinary watercourses, as the Environment Agency has on Main Rivers These provide the connection between a particular source (e.g. high river or tide level) and the receptor that may be harmed (e.g. property). In Pathways flood risk management, pathways are often 'blocked' by barriers, such as flood defences structures, or otherwise modified to reduce the incidence of flooding. Usually associated with convective summer thunderstorms or high intensity rainfall cells within longer duration events, pluvial flooding is a Pluvial flooding result of rainfall-generated overland flows which arise before runoff enters any watercourse or sewer. The approach to be used in the assessment of flood risk which required Precautionary that lack of full scientific certainty, shall not be used to assume flood approach hazard or risk does not exist, or as a reason for postponing cost-effective measures to avoid or manage flood risk Constructing the building in such a way that although flood water may Resilience enter the building, its impact is minimised, structural integrity is maintained and repair, drying & cleaning are facilitated Constructing a building in such a way as to prevent flood water entering Resistance the building or damaging its fabric. This has the same meaning as flood proof Things that may be harmed by flooding (e.g. people, houses, buildings or Receptors the environment) The risk which remains after all risk avoidance, reduction and mitigation Residual risk measures have been implemented The flow of water, caused by rainfall, from an area which depends on how permeable the land surface is. Runoff is greatest from impermeable Runoff areas such as roofs, roads and hard standings and less from vegetated areas - moors, agricultural and forestry land. The sequential approach is a risk-based method to guide development away from areas that have been identified through a flood risk Sequential assessment as being at risk from flooding. Sequential approaches area approach already established and working effectively in the plan-making and development management processes. Source Source refers to a source of hazard (e.g. the sea, heavy rainfall). For there to be flood risk, the three components of flood risk - the source Source-pathway- or the hazard, the receptors affects by the hazard and the mechanism of receptor model transfer between the two - must all exist. This activity focuses on the assessment and management of flood risk within the urban environment from sources primarily resulting from intense rainfall. Surface water management should understand the performance of the urban drainage network, where exceedance flow routes would form and what impact this would have. Solutions to surface Surface water water flood risk can involve green infrastructure provision to capture and management direct these exceedance flows to lower vulnerable areas or open space. New development can provide solutions to reducing runoff not only from the proposed development but also from existing areas. This should be considered in the SFRA in critical areas where development is planned upstream of flooding hotspots. Sustainable A sequence of management practices and control structures, often Drainage Systems referred to as SUDS, designed to drain water in a more sustainable

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Terms Definition (SUDS) manner than some conventional techniques. Typically these are used to attenuate runoff from development sites. An integral part of the plan-making process which seeks to appraise the Sustainability economic, social and environmental effects of a plan in order to inform Appraisal (SA) decision-making that aligns with sustainable development principles TUFLOW is a software package used for 2-Dimensional river modelling. TUFLOW It is used as an analysis tool for flood risk management analysis. Vulnerability NPPF provides a vulnerability classification to assess which uses of land Classes maybe appropriate in each flood risk zone.

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