February 2010

DURHAM COUNTY (LEVEL 1)

Strategic Flood Risk Assessment (SFRA) – Level 1

Report Number: P9514100112-A02 Distribution: Durham County Council Environment Agency Northumbrian Water

Durham County SFRA (Level 1)

Table of Contents

1.0 INTRODUCTION ...... 1

2.0 BACKGROUND TO THE SFRA ...... 1

3.0 THE POLICY FRAMEWORK ...... 2

4.0 DATA INFORMING THE SFRA ...... 4

4.1 Historical Flooding ...... 4

4.2 Areas at Risk of Flooding from Rivers and the Sea...... 5

4.2.1 Flood Zone Maps ...... 5

4.2.2 Flood Defences ...... 6

4.2.3 Flood Warning Areas ...... 6

4.3 Topography ...... 6

4.4 Geology ...... 6

4.5 Previous Flooding Related Investigations ...... 7

5.0 THE RISK OF FLOODING IN DURHAM COUNTY ...... 8

5.1 Brief Description of Durham County ...... 8

5.2 History of Flooding in Durham County ...... 8

5.3 Risk of Flooding from Rivers ...... 9

5.4 Risk of Flooding from the Sea ...... 9

5.5 Risk of Flooding from Surface Water ...... 9

5.6 Risk of Flooding from Groundwater ...... 10

5.7 Risk of Flooding from Reservoirs ...... 10

5.8 Risk to Life due to Flooding (Flood Hazard) ...... 11

5.9 Climate Change ...... 12

5.9.1 Impact of Climate Change upon Fluvial (River) Flooding ...... 14

5.9.2 Impact of Climate Change upon Tidal Flooding ...... 14

5.9.3 Impact of Climate Change upon Surface Water Flooding ...... 14

6.0 PLANNING FOR FLOOD RISK IN DURHAM COUNTY ...... 16

6.1 Responsibility for Flood Risk Management ...... 16

6.2 Spatial Planning ...... 17

6.2.1 PPS25 Flood Zones ...... 17

6.2.2 The Sequential Test ...... 19

February 2010 Report No. P9514100112-A02 i Durham County SFRA (Level 1)

6.2.3 The Exception Test...... 20

6.3 Development management ...... 21

6.3.1 Adopting a Sequential Approach ...... 21

6.3.2 Applying the Exception Test ...... 22

6.3.3 Flood Risk Assessment ...... 22

6.3.4 Mitigating the Risk of Flooding through Design ...... 22

6.4 Emergency Planning ...... 24

7.0 MITIGATING THE RISK OF FLOODING THROUGH DEVELOPMENT ...... 25

7.1 The Flood Risk Assessment (FRA) ...... 25

7.2 Data Sources for Developers ...... 27

7.3 Site Selection & Site Layout (A Sequential Approach) ...... 27

7.4 Building Design ...... 28

7.5 Sustainable Drainage Systems (SUDS) ...... 30

7.5.1 Overview ...... 30

7.5.2 SUDS Maintenance ...... 31

7.5.3 SUDS Approaches ...... 32

7.5.4 The Application of SUDS in County Durham ...... 33

7.6 Safe Site Access ...... 34

7.7 Flood Warning, Planning and Preparation ...... 35

7.7.1 Flood Warning ...... 35

7.7.2 Evacuation Plan (Developers & Site Operators) ...... 35

7.7.3 Flood Plan (Residents & Businesses) ...... 35

8.0 CONCLUSIONS ...... 36

9.0 A LIVING DOCUMENT ...... 36

February 2010 Report No. P9514100112-A02 ii Durham County SFRA (Level 1)

FIGURES

Figure 1 Locality Plan

Figure 2 Policy Framework (Flood Risk Management)

Figure 3 Hierarchy of Flood Risk Management

Figure 4 Flood Warning Areas

Figure 5 Topography

Figure 6 Geology

Figure 7 Flood Defences & Flood Hazard

Figure 8 Reservoirs

Figure 9 Permissible Land Uses

Figure 10 Levels of Detail for a Site Based Flood Risk Assessment (FRA)

Figure 11 Recommended Building Design Approach (vs Flood Depth) Figure 12 Hierarchy of SUDS Techniques

Figure 13 DG5 Register Summary (Northumbrian Water)

APPENDICES

Appendix A Historical Flooding Incidents

Appendix B SFRA Flood Maps (PPS25)

Appendix C The Policy Framework

Appendix D Previous Investigations

Appendix E Data Received to Inform Durham County SFRA

Appendix F Flood Risk Vulnerability Classification (Land Uses)

Appendix G Methodology for delineating Zone 3b Functional Floodplain Appendix H The ‘Simple’ Method (FD2320) – Flood Defence Failure

Appendix I Sustainable Drainage Systems (SUDS) - A Guide for Developers

Appendix J Impact of Climate Change (Zone 3a High Probability)

Appendix K Consultation with Town & Parish Councils

Appendix L Flood Risk throughout County Durham

Appendix M Surface Water Flood Risks Appendix N Recommended Triggers for SFRA Review

February 2010 Report No. P9514100112-A02 iii Durham County SFRA (Level 1)

1.0 INTRODUCTION

There is a long history of flooding within the County of Durham, with records dating back as far as the 14th century. River flooding has resulted in damage and disruption no fewer than six times in the last ten years. Most recently, intense rainfall fell throughout the region on both the 1st and 17th of July 2009, resulting in a substantial number of homes, businesses and roads being affected by floodwaters.

The potential risk that is posed by flooding is therefore generally well recognised and understood in many areas of the County. This Strategic Flood Risk Assessment (SFRA) has been developed to build upon this existing knowledge to provide the Council with an overview of areas that may be susceptible to flooding throughout the County. A County locality plan is provided as Figure 1.

The SFRA considers not only the risk of flooding from the River Wear, the River Tees, and their tributaries. It also provides an overview of flood risk from coastal waters, groundwater, and from surface water runoff. Importantly, the SFRA assesses the likelihood of flooding within the County both today, and also as the risk of flooding increases over time due to climate change.

The SFRA will form part of the evidence base that supports the Durham County Local Development Framework (LDF), informing the selection of sites for future development within the County. The SFRA has been prepared in accordance with Planning Policy Statement (PPS) 25: Development and Flood Risk (December 2006) and the PPS25 Practice Guide (June 2008) for this purpose. Durham County Council commissioned Golder Associates UK Ltd to carry out the Durham County SFRA in July 2009.

2.0 BACKGROUND TO THE SFRA

Durham County Council was given unitary status in April 2009, replacing the district authorities of Easington, Durham City, Chester-le-Street, Wear Valley, Derwentside, Teesdale and Sedgefield. Under the Planning and Compulsory Purchase Act (2004), the newly formed County Council is required to prepare a Local Development Framework (LDF), setting out their strategy for future development within the County to 2026. The LDF will replace the previous district Local Plans and emerging Local Development Frameworks, taking a fresh view of the County as a whole.

A considerable amount of work has been carried out to date by both the district authorities and the Environment Agency to investigate the risk of flooding within the County, as discussed in Section 4.5. These previous investigations have been used extensively to inform this county-wide SFRA.

This Durham County SFRA was prepared by Golder Associates in August 2009, following the flooding that affected in the County in July 2009. This document has been prepared as a Level 1 SFRA, in accordance with the PPS25 Practice Guide1 (June 2008). The Level 1 SFRA is intended to provide an overview of the risk posed by flooding throughout the County from rivers, the North Sea, groundwater, and surface water runoff. The findings and recommendations of this investigation will inform the application of the Sequential Test, as described in Section 6.2.2.

Where a balanced view has been taken (following the application of the Sequential Test), and it is determined by the Council that further consideration of areas at risk of flooding may be warranted on planning grounds, a Level 2 SFRA will be required. The Level 2 SFRA involves a more detailed (local) investigation of the risk of flooding within an emerging development area to ensure that the requirements of the Exception Test (refer Section 6.2.3) can ultimately be met. The Durham County Level 2 SFRA will follow this Level 1 investigation in due course.

1 Refer to PPS25 Practice Guide clauses 3.43 to 3.49 for a description of the Level 1 SFRA

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3.0 THE POLICY FRAMEWORK

The Durham County SFRA is being prepared to inform and guide decisions that are to be taken by the Council as part of the planning process. The scope of the SFRA, and to some degree the method by which the SFRA is been developed, is guided by a framework of policy and guidance that is set out by national government. It is important however to recognise that the SFRA is a technical, non-statutory, document. For this reason, the implementation of the SFRA relies heavily upon the presence of a robust framework of local, regional and national planning policy that is able to uphold the findings and recommendations of the study.

An overview of the policy framework within which the Durham County SFRA has been prepared is provided in Figure 2 below, taken from Figure 2.2 of the PPS25 Practice Guide.

Figure 2 Policy Framework (Flood Risk Management) Figure 2.2 - PPS25 Practice Guide (CLG, June 2008)

This figure indicates the inter-relationships that exist between this SFRA, and the work that has been completed by the Environment Agency and the North East Assembly2 in relation to the risk of flooding within the County. These documents are discussed further in Section 4.5 and Appendix D. A summary of the national, regional and local planning policy that underpins the development and implementation of the Durham County SFRA is provided in Appendix C.

To fully appreciate the findings and recommendations of this SFRA, it is important to reflect on the manner by which the planning process can positively contribute to a reduction in the risk of flooding within the County.

2 Abolished in March 2009

February 2010 Report No. P9514100112-A02 2 Durham County SFRA (Level 1)

Historically, communities developed next to rivers to provide an important source of water, transportation and power, and flooding was generally accepted as an inevitable part of life. Our perception of risk has changed over time however, and our homes are less resilient to the damage caused by floodwaters. It is increasingly important therefore that we understand the risks that are posed by flooding, and that these risks are managed proactively. To assist with this, the government has set out a hierarchy for the management of flood risk within our towns and cities. This is presented in Figure 3 below, taken from Figure 2.1 of the PPS25 Practice Guide.

Most Sustainable Approach

Least Sustainable Approach

Figure 3 Hierarchy of Flood Risk Management Figure 2.1 - PPS25 Practice Guide (CLG, June 2008)

In summary, local planning authorities are encouraged wherever possible to avoid vulnerable development within areas at risk of flooding, applying the principles of the sequential approach (see Section 6.2). It is recognised however that this may not always be achievable, and that in certain circumstances other pressing planning considerations may require a site to be considered further, despite its susceptibility to flooding. In these circumstances, it is very important that the development is designed to ensure that the potential risks both to the site itself, and the surrounding area, are safely managed. This philosophy has underpinned the development of the Durham County SFRA.

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4.0 DATA INFORMING THE SFRA

A considerable amount of knowledge exists in relation to the risk of flooding throughout the County of Durham, providing the basis for the development of the Durham County SFRA. A summary of the information collated, reviewed and presented within the SFRA is provided in this section. A list of all data received as part of the current investigation is provided in Appendix E.

4.1 Historical Flooding

There is a considerable wealth of historical flooding information available to inform the SFRA, dating back as far as the 14th century. This includes incidents of flooding from rivers, flooding from sewers and highway drains, and flooding due to overland runoff from local fields. Historical flooding information is extremely valuable, providing a clear indication of (for example) areas that are susceptible to flooding on a frequent basis, and areas that are particularly vulnerable when a flood occurs.

The following sources of historical flooding information have been investigated during the development of the Durham County SFRA. 1. Previous Investigations

Strategic Flood Risk Assessments (2008)

The previous district authorities of Wear Valley, Durham City, Chester-le-Street, and Derwentside commissioned Entec to carry out a Strategic Flood Risk Assessment (SFRA) in 2008. A county-wide appraisal of flood risk was also carried out at this time to inform the evaluation of minerals and waste sites. As part of these investigations, consultation was undertaken with County and District Council drainage engineers, and the local community (via community groups and town and parish councils). The purpose of this consultation was to collate any observed incidents of historical flooding throughout the study area.

This information has been collated, forming the starting point for all further consultation and analyses that have been completed as part of the current investigation. The data collected is presented on the SFRA flood maps (Appendix B) and in Appendix A.

Catchment Flood Management Plans (2008)

The Environment Agency has recently completed Catchment Flood Management Plans (CFMPs) for the River Wear, River Tyne and River Tees catchments respectively, as discussed in Section 4.5. A comprehensive literary review was carried out as part of the CFMP process to collate all known incidents of river flooding that have been observed within the study areas. These incidents have been provided by the Environment Agency for SFRA purposes, and are duplicated in Appendix A of this report.

2. Council Engineers (Highways & Drainage)

Consultation with the previous District and County Council drainage engineers was carried out as part of the earlier 2008 SFRA, as explained above. Flooding was observed within the County in July 2009 however, and so the opportunity was taken to consult with the (post April 2009) Durham County Council drainage and highway engineers to identify those areas that were affected by flooding in the recent event. The information provided is presented in the SFRA flood maps (Appendix B) and Appendix A.

February 2010 Report No. P9514100112-A02 4 Durham County SFRA (Level 1)

3. Town & Parish Councils

Once again, consultation with community groups and Town & Parish Councils was carried out as part of the earlier 2008 SFRA. In light of the July 2009 flooding event however, consultation with Town & Parish Councils was undertaken, seeking any information relating to recent flooding that may have occurred.

The information provided by the Town & Parish Councils is presented in the SFRA flood maps (Appendix B) and Appendix A. A copy of the letter that was circulated for consultation purposes, together with a list of those authorities that were contacted and/or responded is also provided in Appendix K.

4. Northumbrian Water

Northumbrian Water capture known incidents of sewer flooding throughout the County in the DG5 At-Risk Register. A summary of the register has been disseminated for SFRA purposes, providing an overview of the number of properties that have been affected by sewer flooding (internally and/or garden areas) over the past 10 to 20 years. The DG5 At-Risk Register is presented as Figure 13.

5. Environment Agency

The Environment Agency collates information relating to historical flooding from rivers, and this has been provided for SFRA purposes. Flood outlines have been made available for observed events on the River Wear between 1963 and 2007, and these are presented in Appendix A.

It is noted that this dataset provides a summary of only those incidents that were physically captured and reported by the local community (or the Environment Agency) following a flooding event. It is reasonable to assume that not all areas that were affected at that time have been captured, and it follows therefore that this does not necessarily provide a complete record of all river flooding that may have occurred in the County during the event in question.

4.2 Areas at Risk of Flooding from Rivers and the Sea

4.2.1 Flood Zone Maps

The Environment Agency has carried out a number of detailed flood modeling and mapping investigations within the study area. The resulting flood maps provide an overview of the areas of the County that may be susceptible to river flooding. The detailed hydrological and hydraulic modeling investigations have been undertaken progressively over a number of years, and consequently the quality and accuracy of the model predictions is variable.

For planning purposes therefore, the Environment Agency has published a national Flood Zone Map, providing a readily accessible depiction of areas of the County that will be affected by floodwaters in a 0.1% (1 in 1000) and a 1% (1 in 100) fluvial3 flood event, referred to as Zone 2 and Zone 3 respectively. The Flood Zone Map is a compilation of the best available information for the location in question at the time of publication. This may include (for example) detailed hydraulic modeling outputs, national flood mapping outputs, and/or observed flooding extents. The Flood Zone Map published in April 2009 has been provided by the Environment Agency, forming the basis for the delineation of Zone 2 Medium Probability and Zone 3a High Probability (see Section 6.2.1) within the Durham County SFRA.

3 Or 0.5% (1 in 200) tidal flood event, whichever is greater

February 2010 Report No. P9514100112-A02 5 Durham County SFRA (Level 1)

4.2.2 Flood Defences

It is important to highlight that the presence of raised flood defences does not fully remove the risk of flooding. There will always remain a residual risk that the flood defences will overtop, or collapse (breach) while water levels in the river are high. This will result in floodwater entering the defended area behind the raised defences, and often this will occur suddenly with little warning.

It is for this reason that the Environment Agency Flood Zone Map ignores the presence of raised flood defences. This provides a realistic depiction of areas that would be a risk of flooding if a sudden failure of the flood defences was to occur, and/or future investment in the maintenance of the defences was withdrawn (resulting in their removal in the longer term).

From a planning perspective, it is important that these residual risks are taken into consideration when allocating future development. Consequently the removal of flood defences is an approach that is also mirrored in the delineation of Zone 3a and Zone 2 within PPS25. This is explained further in Section 6.2.1.

The locality and height of raised flood defences has been provided by the Environment Agency for SFRA purposes, and these are presented in the SFRA Flood Maps (Appendix B) and Figure 7.

4.2.3 Flood Warning Areas

In some areas of the County, it is inevitable that flooding will be experienced at some stage. When flooding does occur, it is important that members of the local community are informed, providing them with an opportunity to raise or relocate belongings, and (where necessary) to evacuate safely. Effective flood warnings are one of the tools that may be available to forewarn of a pending flood event.

The Environment Agency is continuously working to improve the availability of flood warnings to areas at risk of river flooding throughout the study area. Areas of the County that currently receive a flood warning are presented on the Environment Agency’s website, and these are presented indicatively in Figure 4.

4.3 Topography

A county-wide digital elevation model (DEM) has been provided by Durham County Council to support the development of the SFRA, and to enable the assessment of areas of the County that may be susceptible to surface water flooding. An overview of the County topography is presented in Figure 5.

It is noted that no information could be made available from the Council in relation to the source or accuracy of the DEM that has been used for surface water modelling purposes as part of this investigation. For this reason, considerable effort has been made to ‘ground truth’ both the source data, and the findings of the modelling exercise, to ensure the accuracy of the SFRA outcomes. This is discussed further in Appendix M.

It has been concluded that the DEM provides a thorough and robust representation of the local topography within the County of Durham, and is entirely suitable for the purposes of this investigation.

4.4 Geology

An overview of the County geology has been established from published 1:625,000 geological maps of the region (British Geological Society), and this is presented in Figure 6.

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4.5 Previous Flooding Related Investigations

A number of investigations have been carried out in recent years by those collectively responsible for the analysis and management of flood risk within the County of Durham. A brief overview of the studies that have been reviewed to inform the development of this SFRA is provided in Appendix D.

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5.0 THE RISK OF FLOODING IN DURHAM COUNTY

5.1 Brief Description of Durham County

The County of Durham is characterised by high ground to the west, and lower undulating ground to the east. The River Wear corridor runs through the heart of the County, along which a wide tranche of relatively low lying land extends in a northerly direction, encompassing the towns of Chester-le-Street and Durham.

A similarly characteristic ‘split’ is evident across the County when considering land use. The west of the County, i.e. ‘the North Pennines Area’, is characterised by small rural settlements and small market towns. In contrast, the east of the County is still rural, however this area is characterised by towns that were built to support the mining of steel and coal. These old industrial areas are now experiencing a pressing demand for urban regeneration.

The high ground to the west of the River Wear is underlain by Yoredale (limestone geology) with a peat soil layer. The central belt of the County is situated on coal measures, and these are overlain by till. To the east, Zechstein (limestone) geology dominates, once again with till as the surface soils. Alluvium, sands and gravels are evident along the corridors of the River Wear and River Tees, with isolated lenses of clay to the north and south of the County respectively.

5.2 History of Flooding in Durham County

There is a long history of flooding in the County of Durham, with records dating back to the 14th century. The Environment Agency has prepared a comprehensive summary of known flooding events within the River Wear and River Tees catchments since this time (to 2008), and this is provided in Appendix A. It is emphasised that these incidents relate exclusively to river flooding, and do not include the recent July 2009 flood.

In addition, a considerable wealth of knowledge exists in relation to surface water and groundwater flooding events that have been experienced throughout the County. This has been collated as part of this SFRA as explained in Section 4.5, capturing in this instance the flooding that occurred in July 2009. This information is presented in the SFRA flood maps (Appendix B) and in Appendix A.

River flooding within the County is primarily due to the overtopping of the River Wear and its tributaries in towns and villages along its length. Riverfront areas in Durham city centre have experienced flooding from the River Wear on 5 occasions in the last 10 years, most recently in July 2009. There are relatively few incidents of flooding from the River Tees within the County, although flooding has been experienced historically in Barnard Castle, exacerbated by a coincident snowmelt that increased water levels in the river.

There are a substantial number of reported incidents of surface water flooding throughout the County, and the recent July 2009 event was a timely reminder of the susceptibility to flooding following particularly heavy (and prolonged) rainfall. It is understood that on the 2nd of July approximately 50mm of rainfall fell in around 40minutes over some areas of the County. On the 17th of July a second rainfall event occurred, with over 100mm falling in a 24hour period. The feedback received from Town & Parish Councils has provided some very useful eyewitness accounts of the flooding that resulted, with some areas subjected to relatively deep floodwaters, affecting homes and thoroughfares.

February 2010 Report No. P9514100112-A02 8 Durham County SFRA (Level 1)

5.3 Risk of Flooding from Rivers

There is a long history of flooding from rivers in County Durham, centred largely around the River Wear and its tributaries. Collated records of historical river flooding incidents are provided in Appendix A. For planning purposes however it is necessary to assess the predicted extent of flooding in a 5% (1 in 20) and a 1% (1 in 100) design flood event, depicting Zone 3b Functional Floodplain and Zone 3a High Probability respectively.

The Environment Agency has carried out detailed modelling within the River Wear and River Tees catchments, as explained in Section 4.2. As part of the current investigation, further coarse analysis of Zone 3b Functional Floodplain and Zone 3a plus Climate Change have been carried out, and these are discussed in Section 6.2.1 and 5.9 respectively. Those areas within the County that are at risk of flooding from rivers in the PPS25 delineated design events are presented in the SFRA Flood Maps (Appendix B). A more detailed discussion of historical and predicted river flooding impacts within areas of the County is provided in Appendix L for reference purposes.

It is important to reiterate that the delineation of the PPS25 flood zones is undertaken disregarding the presence of raised flood defences. This approach is taken to reflect the fact that it is not possible to fully engineer away the risk of flooding. There will always be a residual risk that the flood defence may be over topped, or it may collapse during a flooding event. Planning decisions must therefore be fully aware of these residual risks. The location of formal flood defences throughout the County is indicated in the SFRA Flood Maps (Appendix B) and Figure 7. The residual risk of flooding associated with raised flood defences is discussed in Section 5.8.

5.4 Risk of Flooding from the Sea

The coastal frontage of Durham County extends from Seaham in the north to Crimdon Park in the south. The town of Seaham is situated immediately next to the coast, however the coastal communities of Dawdon, Easington Colliery, Horden and Blackhall Colliery are some distance inland (typically around 0.5km). The coastline is characterised by beach cliffs, and historically sea defences have been constructed to prevent the erosion of the seafront in Seaham. Consequently, the risk of tidal flooding to property within the County of Durham is negligible. This is reinforced by the SFRA Flood Maps, provided in Appendix B.

The impact of sea level rise as a result of climate change has been considered, as discussed in Section 5.9. In summary, it is reasonable to assume that there will be no increase in the risk of coastal flooding due to climate change.

5.5 Risk of Flooding from Surface Water

A considerable number of localised (surface water) flooding incidents have been captured throughout the County. Many of these are situated within developed areas, affecting homes and businesses. Within more rural areas however, a number of surface water flooding incidents are evident, resulting in road closures.

It is understood that ongoing investment is being placed into progressively improving the drainage system by Northumbrian Water and Durham County Council, prioritising areas of greatest need. This will increase the capacity of the drainage system to typically 2.5% (1 in 40) where improvements have been carried out, including (most recently) communities within Durham and Chester-le-Street. The County covers a substantial area however, and with only finite funding available, it is inevitable that a risk of surface water flooding will remain in many areas. It is important therefore that the Council has a thorough understanding of this risk, allowing them to guide limited resources to areas of greatest need, and ensuring that future development does not exacerbate the problem over time.

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The risk of surface water flooding has been interrogated for the County as a whole, highlighting (and prioritising) areas that may be susceptible to ponding and/or overland flow following periods of heavy rainfall. The findings of this appraisal are presented in Appendix M.

5.6 Risk of Flooding from Groundwater

No records of groundwater flooding have been found within the County of Durham. In 2004, Defra commissioned Jacobs to carry out a detailed investigation into areas of potential ‘groundwater emergence’ throughout England. This study concluded that there were no areas of predicted groundwater flooding within this area.

It is worth noting that there is a long history of coal mining within the north east region, and it is understood that mine dewatering has recently ceased in some areas. This may lead to an increase in groundwater levels within historical mining areas of the County, and discussions have been held with Council engineers accordingly. It has been concluded (from a strategic perspective) that there is a high level of uncertainty as to the long term impacts of the cessation of dewatering upon groundwater levels, and there is no evidence that groundwater flooding will ensue.

Finally, the Environment Agency has delineated a series ‘groundwater source protection zones’ for England and Wales. These are mapped to assist the Environment Agency monitor the risk of contamination from activities that may pollute important groundwater resources in the area. A relatively large proportion of the area to the east of the A1(M) within Durham County has been delineated as a source protection zone, confirming the presence of groundwater within this area. In summary however, it would appear that the potential risk of groundwater flooding in the County of Durham is very small.

5.7 Risk of Flooding from Reservoirs

A number of water storage reservoirs have been identified within the County, and these are highlighted in Figure 8. Many of those highlighted are relatively large structures, storing a considerable volume of water behind a man-made raised dam wall or embankment. The consequence of a sudden failure of this structure could potentially be catastrophic for communities situated immediately downstream, and flooding could occur along riverfront areas some distance away.

Currently, the safety of large reservoirs (exceeding 25,000m3 capacity) is managed under the Reservoirs Act 1975. The Draft Floods & Water Bill (April 2009) however will, once enacted, supersede the Act. This new legislation will require all water storage reservoirs greater than 10,000m3 in volume to be included on an Environment Agency register. The Environment Agency will be responsible for assessing the potential consequence of failure for each registered reservoir, in particular whether there is a direct threat to human life. Clear responsibilities will be placed upon regulators and operators for all structures, with particular emphasis upon those reservoirs that will pose a risk to life should a failure occur.

In summary, whilst the potential risk of dam failure is very low, the emergency situation that arose surrounding the Ulley Reservoir in Rotherham in 2007 reinforced the importance of effective risk management. A thorough understanding of the potential consequences of a sudden dam failure is required, informing an emergency response plan that can be rapidly enacted to minimise the potential risk to life.

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Given the very low risk surrounding reservoir failure, there are currently no specific planning constraints that should hinder future development within areas downstream of the existing Durham County reservoirs. A broad awareness of their presence should be borne in mind however, and common sense applied to avoid placing new development at unnecessary risk.

5.8 Risk to Life due to Flooding (Flood Hazard)

There are a number of areas within the County that are provided a degree of protection against river flooding through the presence of raised flood defences. These defences are typically (though not exclusively) maintained by the Environment Agency, and will generally be either an earth embankment or a ‘hard’ (steel or concrete) wall.

Those flood defences that have been constructed specifically to reduce the risk of flooding to communities, and are maintained accordingly, are referred to as ‘formal flood defences’. The known formal flood defences within the County of Durham are highlighted in the SFRA Flood Maps (Appendix B) and Figure 7.

The long term integrity of these defences is an important consideration when evaluating whether future development should be permitted within a defended area. The following key issues should be carefully considered: Z The height of the defence in comparison with current predicted peak design flood levels (i.e. what is the standard of protection provided by the defence)?

Z The height of the defence in comparison with future predicted flood levels (i.e. what will be the standard of protection provided in future years as flood levels rise with climate change)?

Z The structural integrity of the defence, and how will this be maintained over time?

Z The risk of flooding to property should the river over-top of the defence?

Z The risk of flooding to property, and to individuals, should the defence fail catastrophically (i.e. breach) when river levels are high?

The detailed assessment of flood defence overtopping and/or breach should be carried out as an integral part of a site-based flood risk assessment. For Level 1 SFRA purposes however, a coarse appraisal of areas that may be subject to some degree of risk as a result of flood defence failure has been carried out.

A ‘simple method’ approach has been adopted, in accordance with FD23204 (Defra, 2005), and as described in Appendix H of this report. This provides an indication of potential danger zones for members of the public, based upon the height of the flood defence, in an overtopping and a breach failure scenario. The danger envelope has then been truncated to the 0.1% (1 in 1000) flood extent (i.e. Zone 2 Medium Probability) to reflect the natural topography of the floodplain, as depicted in Figure 7. The resulting danger (or flood hazard) zone should be used by the Council and the developers to trigger a more detailed appraisal of residual risk as part of the site based flood risk assessment.

4 “Flood Risk Assessment Guidance for New Development (Phase 2), Framework and Guidance for Assessing and Managing Flood Risk for New Development – Full Documentation and Tools, R&D Technical Report FD2320/TR2” (Defra, October 2005)

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It is important to recognise that there may be structures within the County that alter the path of floodwaters, and in doing so provide a degree of protection to properties that would otherwise be at risk. These are referred to as ‘informal defences’ and may include (for example) boundary walls, fences, or road embankments. It is not feasible to identify all informal defences throughout the County as part of a county- wide Level 1 SFRA, however it is important that any site-based investigations5 consider the presence of informal defences from a local perspective.

5.9 Climate Change

Climate change is widely expected to increase the intensity and frequency of rainfall events throughout the UK, which in turn will increase the frequency and severity of flooding within the County of Durham. Climate change is also expected in increase sea levels in the North Sea.

The potential impacts of climate change upon precipitation (rainfall) and sea levels have been extensively modelled, and Appendix B of PPS25 provides guidance as to how climate change should be taken into account for planning purposes. The UKCP09 climate change projections were released in the summer of 2009 by the Met Office however, providing a probabilistic overview of predicted climate changes for the North East region of England. These are presented below, and an appraisal of both approaches has been carried out for comparison purposes.

Table A Predicted Sea Level Rise due to Climate Change Appendix B, PPS25 (2006)

Table B Predicted Increase in Rainfall & River Flow due to Climate Change Appendix B, PPS25 (2006)

5 Including the Level 2 SFRA and detailed developer-led Flood Risk Assessments (FRA)

February 2010 Report No. P9514100112-A02 12 Durham County SFRA (Level 1)

UKCP09 Medium Emissions Scenario (Edinburgh) Relative Sea Level Rise (cm) from 1990 Levels

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2095

1.6 3.5 5.7 8.2 10.9 13.9 17.1 20.6 24.4 28.4 30.5

Table C Predicted Sea Level Rise due to Climate Change UK Climate Projections (UKCP) 09, Met Office (2009)

UKCP09 Medium Emissions Scenario (North East Region) Increase in Mean Precipitation (%)

Probability Level 2020 2050 2080

Summer Emissions

10% very unlikely to be less than -10% to -20% -20 to -30 -30

33% unlikely to be less than -10 to 0 -10 to -20 -20

50% central estimate 0-10-10

67% unlikely to be greater than 0 0 -10 to 0

90% very unlikely to be greater than 10 10 10

Winter Emissions

10% very unlikely to be less than 0% 0 to 10 0 to 10

33% unlikely to be less than 10 10 10 to 20

50% central estimate 10 10 to 20 20

67% unlikely to be greater than 10 20 20 to 30

90% very unlikely to be greater than 20 20 to 40 20 to 50

Table D Predicted Increase in Rainfall due to Climate Change UK Climate Projections (UKCP) 09, Met Office (2009)

PPS25 requires local authorities and developers to consider the potential impact of climate change as part of the planning process, over the lifetime of the proposed development. PPS25 recommends that, for planning purposes, the ‘lifetime of development’ is assumed to be 100 years for residential development, and 60 years for commercial development. In accordance with PPS25, the impact of climate change should be considered for the 1% (1 in 100) design event.

February 2010 Report No. P9514100112-A02 13 Durham County SFRA (Level 1)

5.9.1 Impact of Climate Change upon Fluvial (River) Flooding

The Environment Agency has carried out detailed modelling of selected reaches of the River Wear in the Chester-le-Street area, providing a robust assessment of the likely impact of a 20% increase in the 1% (1 in 100) peak design river flow. In other areas of the River Wear corridor (including Durham) the 0.5% (1 in 200) design event has been modelled, once again providing a reasonable approximation of a 20% increase in the 1% (1 in 100) peak design river flow. These modelled increases mimic the indicative changes that are expected over a 100 year period within the River Wear catchment, offering a good insight into the likely impacts that climate change will have on river flooding within the County area.

Within those areas in which detailed modelling has been undertaken, it is evident that climate change is unlikely to result in a marked increase in the extent of flooding (and hence number of properties affected by flooding) in the 1% (1 in 100) design event. It is reasonable to assume however that those properties that are currently at risk of flooding will become more susceptible, with the frequency and severity of flood events steadily increasing over time.

Where detailed modelling has not been undertaken by the Environment Agency, engineering judgement has been exercised to provide an indication of areas that are likely to be affected over the next 100 years as a result of climate change. A comparison between the estimated 1% (1 in 100) and 0.1% (1 in 1000) peak design flows throughout the region has been carried out to assess how reasonably the 0.1% (1 in 1000) event mimics the anticipated increase in flow associated with climate change.

In summary, it has been concluded that, in many areas of the County, the Zone 2 Medium Probability flood outline (representing the 0.1% (1 in 1000) flood extent) is likely to be an over-prediction of the 1% (1 in 100) plus climate change. A proportional change in the anticipated flood extent has been adopted accordingly for planning purposes, as reflected in the maps provided in Appendix J.

5.9.2 Impact of Climate Change upon Tidal Flooding

The Durham County coastline is characterised by a cliff frontage, and current sea level projections indicate that there is no measurable risk of tidal flooding to the coastal community of Seaham (or nearby towns) in the existing 0.5% (1 in 200) or 0.1% (1 in 1000) predicted sea levels.

Adopting the PPS25 (Appendix B) guidance for climate change projections, it is estimated that there will be an increase of approximately 875mm in the 0.5% (1 in 200) peak design sea level over the next 100 years. Under UKCP09 projections for nearby Edinburgh, this increases to approximately 1600mm, assuming a ‘medium’ emissions scenario. In either circumstance, this increase in predicted maximum sea level will not result in any flooding of coastal frontages within the County.

5.9.3 Impact of Climate Change upon Surface Water Flooding

As indicated in the PPS25 and UKCP09 projections provided above, an increase in predicted rainfall intensity is expected over the next 100 years. The likelihood and severity of surface water flooding is directly proportional to the intensity of localised rainfall over the County, and for this reason an increase in the risk of flooding events of this nature can be expected as a result of climate change.

February 2010 Report No. P9514100112-A02 14 Durham County SFRA (Level 1)

Broad scale modelling has been carried out as part of the SFRA process to identify those areas that may be at risk of surface water flooding within the County. A large number of historical incidents have also been captured as part of the comprehensive data collation and consultation phases of this SFRA. Climate change is likely to increase the frequency and severity of localised flooding at these locations, highlighting the importance of proactive infrastructure planning (to improve drainage) and effective development management.

February 2010 Report No. P9514100112-A02 15 Durham County SFRA (Level 1)

6.0 PLANNING FOR FLOOD RISK IN DURHAM COUNTY

6.1 Responsibility for Flood Risk Management

There are many stakeholders that collectively share responsibility for the management of flood risk in England, including (within the County of Durham): Z Communities & Local Government (CLG) CLG is responsible for putting into place the national policy framework within which the local planning process is carried out. Spatial planning decisions (i.e. where development should be permitted to occur), and development management decisions (i.e. how and what development should be permitted to occur) must be taken in accordance with CLG planning policy, specifically Planning Policy Statement (PPS) 25: Development and Flood Risk from a flood risk perspective.

Z Department of Environment, Food & Rural Affairs (Defra) Defra has overall responsibility for the direction (i.e. decision making) and funding of flood risk management in England. The practical implementation of strategies and/or schemes to reduce the risk of flooding is carried out by others, including the Environment Agency, local authorities, and internal drainage boards.

Z Environment Agency The Environment Agency has permissive powers for the management of flood risk arising from designated main rivers6 and the sea. This may include (for example) the maintenance of rivers and riverbanks, the construction of flood defences, and the operation of flood control structures during a flooding event. The Environment Agency is also responsible for flood forecasting, and the dissemination of flood warnings.

PPS25 stipulates that the Environment Agency is a statutory consultee that must be consulted at all stages of the planning process, within areas that are at risk of flooding. Finally, within the Draft Floods & Water Bill (April 2009), the Environment Agency is given a strategic overview role, under which they will be responsible for providing support and advice to local authorities in relation to the management of surface water and groundwater flooding.

Z Durham County Council As the planning authority, Durham County Council is responsible for appraising the risk of flooding (from all sources), and using this knowledge to inform decision making relating to: the allocation of land for future development; the setting of local planning policy; determining planning permission for future development; and working with partners to respond effectively in a flooding emergency.

Following the enactment of the Draft Floods & Water Bill (expected late 2009), it is expected that the Council will be given responsibility for the management of surface water within the County, working collaboratively with the Environment Agency and Northumbrian Water.

Z Northumbrian Water Northumbrian Water holds overall responsibility for the provision of water within the County, and the disposal of sewage. Whilst Northumbrian Water has no direct responsibility for flood risk management per se, it is recognised UK-wide that ageing sewers are contributing to the risk of surface water flooding following heavy rainfall. To this end, the Draft Floods & Water Bill (April 2009) requires water authorities throughout England to work collaboratively with local authorities and the Environment Agency to address the risk of flooding within local communities.

6 Main rivers are designated watercourses that fall under the auspice of (i.e. are maintained) by the Environment Agency. Larger rivers, and streams that pose a risk of flooding to property, will typically hold ‘main river’ status

February 2010 Report No. P9514100112-A02 16 Durham County SFRA (Level 1)

Furthermore, Northumbrian Water is continually investing in sewer upgrades within areas that are known to have suffered sewer flooding historically7. Recent system upgrades include Belmont, Carrville and Chester-le-Street.

Z Landowners Within England, landowners are ultimately responsible for the protection of their own property against flooding. They are also responsible for ensuring that their property does not contribute to a risk of flooding elsewhere. A considerable amount of advice is available from the Environment Agency to assist landowners, much of which can be sourced from their website at www.environment- agency.gov.uk. It is worth noting that particular responsibilities fall upon landowners whose properties adjoin a river or watercourse, and the Environment Agency has released a guidance note entitled “Living on the Edge - A Guide to the Rights and Responsibilities of Riverside Occupation”. This can be found at http://publications.environment-agency.gov.uk/pdf/GEHO0407BMFL-e- e.pdf?lang=_e.

6.2 Spatial Planning

PPS25 places a statutory requirement upon Durham County Council to consider the risk of flooding when determining where, and what type of, development should be allocated within the County. The national planning policy advocates a sequential approach to the allocation of sites for future development (and/or regeneration) in which areas of very low (or no) flood risk are sought as a priority. The practical implementation of the sequential approach is delivered by the Council through the application of the Sequential Test and (where applicable) the Exception Test. These are explained further in Section 6.2.2 and 6.2.3 respectively.

6.2.1 PPS25 Flood Zones

The application of the PPS25 Sequential and Exception Tests requires an understanding of the spatial variation in flood risk across the County area. The primary purpose of the Durham County SFRA therefore is to provide the Council with an overview of areas that will be susceptible to flooding (from rivers and the sea) in a range of design flood events. This susceptibility to flooding has been determined in accordance with the definitions provided within PPS25, delineating a series of ‘flood zones’ as described below: Zone 3b Functional Floodplain

Zone 3b Functional Floodplain is defined within PPS25 as “land where water has to flow or be stored in times of flood. SFRAs should identify this Flood Zone (land which would flood with an annual probability of 1 in 20 (5%) or greater in any year or is designed to flood in an extreme (0.1%) flood, or at another probability to be agreed between the LPA and the Environment Agency, including water conveyance routes).”

For the purposes of the Durham County SFRA, Zone 3b Functional Floodplain has been defined in the following manner: Z Detailed modelling of the 5% (1 in 20) design event within the River Wear has been carried out by the Environment Agency in Durham and Chester-le-Street. The predicted flood extents arising from this detailed modelling have been provided, and these have been adopted as Zone 3b within Durham and Chester-le-Street respectively.

7 As identified in the DG5 register, discussed in Section XX of this report

February 2010 Report No. P9514100112-A02 17 Durham County SFRA (Level 1)

Z There are a number of water storage reservoirs throughout the County. These have been delineated as Zone 3b for planning purposes.

Z Within rural areas of the County (typically encompassing areas to the west of the A68), it is recommended that natural floodplain areas are protected from future development. For this reason, Zone 3b has been delineated as the 1% (1 in 100) design flood extent within these rural stretches for planning purposes.

Z Where villages are situated in close proximity to a river corridor, coarse modelling of the 5% (1 in 20) design event has been undertaken to provide an indication of the Zone 3b extent. The adopted methodology is described in Appendix G.

It is noted that the adopted approach is somewhat conservative, and is likely to provide a slight over-estimation of the 5% (1 in 20) flood extent. From a planning perspective however, this provides the Council and developers with a reasonable indication of those areas within which PPS25 is likely to constrain the scale and nature of development.

Zone 3a High Probability

Zone 3a High Probability is defined within PPS25 as “land assessed as having a 1 in 100 or greater annual probability of river flooding (>1%) or a 1 in 200 or greater annual probability of flooding from the sea (>0.5%) in any year.”

For the purposes of the Durham County SFRA, Zone 3a High Probability has been defined using the Environment Agency Flood Zone Map (April 2009). This is described in Section 4.2.1.

Zone 2 Medium Probability

Zone 2 Medium Probability is defined within PPS25 as “land assessed as having between a 1 in 100 and 1 in 1000 annual probability of river flooding (1% – 0.1%) or between a 1 in 200 and 1 in 1000 annual probability of sea flooding (0.5% – 0.1%) in any year.”

For the purposes of the Durham County SFRA, Zone 2 Medium Probability has been defined using the Environment Agency Flood Zone Map (April 2009). This is described in Section 4.2.1.

Zone 1 Low Probability Zone 1 Low Probability is defined within PPS25 as “land assessed as having a less than 1 in 1000 annual probability of river or sea flooding in any year (<0.1%).”

For the purposes of the Durham County SFRA, Zone 1 Low Probability has been defined as all land that is situated outside of Zone 3b, Zone 3a and Zone 2.

It is important to emphasise that, whilst the risk of flooding from rivers and/or the sea is very low within Zone 1, land situated within this zone may still be subject to flooding from groundwater and/or surface water sources.

February 2010 Report No. P9514100112-A02 18 Durham County SFRA (Level 1)

6.2.2 The Sequential Test

PPS25 requires local authorities to apply the Sequential Test at all stages of the planning process. From a spatial planning perspective therefore, it is necessary for Durham County Council to carry out the Sequential Test to guide where (and what type) of development will be allocated within the LDF.

The Sequential Test is described in Clause D5 (Appendix D) of PPS25, requiring the following thought process to be applied when considering the allocation of sites: 1. “The overall aim of decision-makers should be to steer new development to Flood Zone 1.

2. Where there are no reasonably available sites in Flood Zone 1, decision-makers should take into account the flood risk vulnerability of land uses and consider reasonably available sites in Flood Zone 2.

3. Only where there are no reasonably available sites in Flood Zones 1 or 2 should decision-makers consider the suitability of sites in Flood Zone 3, taking into account the flood risk vulnerability of land uses.”

As highlighted in points (2) and (3) above, when considering the Sequential Test the Council must consider not only the locality of a site, but also the land use that will be permitted. The permissible ‘flood risk vulnerability’ of land uses within flood affected areas of the County is summarised in Table D.3 of PPS25, and duplicated as Figure 9 below.

Figure 9 Permissible Land Uses (Flood Risk Vulnerability) under PPS25 Table D.3, Appendix D, PPS25 (December 2006)

Typically, residential development is considered ‘more vulnerable’ for planning purposes, whereas commercial development will generally fall into the ‘less vulnerable’ category. ‘Highly vulnerable’ development includes emergency services depots that must functional and accessible during a flooding situation. A comprehensive list of land use vulnerability categories is provided in Table D.2 of PPS25, and duplicated in Appendix F of this report.

February 2010 Report No. P9514100112-A02 19 Durham County SFRA (Level 1)

Existing Development in Zone 3b Functional Floodplain Areas of existing riverside development are common place in some of the County towns, including (for example) Durham City, Chester-le-Street and Bishop Auckland. On a relatively small number of occasions, these areas of existing riverside development fall within the 4% (1 in 25) design flood extent, and therefore are delineated as Zone 3b Functional Floodplain within the Durham County SFRA.

Whilst the policy aim in Zone 3b is to relocate existing development to make space for water, the benefit of the development to the viability of these towns, and the sustainability aims of the Local Development Framework, may outweigh the flood risk.

It is acknowledged that existing buildings and structures are likely to impact on the functionality of the floodplain by impeding conveyance and reducing the storage of floodwater. In such situations, it may be argued that these developed areas of the site are therefore not functional floodplain, as defined by PPS25. In these exceptional circumstances therefore, the developer should carry out a more detailed site-based Flood Risk Assessment to thoroughly examine the functionality of the floodplain within the boundaries of the site.

Where it can be demonstrated that the presence of existing infrastructure (buildings) severely restricts the movement and/or storage of floodwater within the site, then these areas of the site may be re-defined as Zone 3a High Probability and re-developed accordingly. This realignment of Zone 3b may only be undertaken with the agreement of the Council and the Environment Agency

Application of the Sequential Test will be required before re-use of these sites is considered appropriate. Where re-use of the site is deemed to be suitable, the hazard posed by flooding should be assessed using detailed modelling and opportunities should be sought to reduce the overall level of flood risk within the site. This may achieved by (for example) locating the higher vulnerability class uses to areas of the lowest flood risk, by building in increased flood storage and flood flow routes through the layout and form of development and through the appropriate application of sustainable drainage techniques.

It is important to recognise that the Sequential Test is intended to be applied not only to the County as a whole, but also within each flood zone. PPS25 (Clause D6) states:

“Within each Flood Zone, new development should be directed first to sites at the lowest probability of flooding and the flood vulnerability of the intended use matched to the flood risk of the site, e.g. higher vulnerability uses located on parts of the site at lowest probability of flooding.”

6.2.3 The Exception Test

Following the application of the Sequential Test, it may be necessary for further consideration of both the proposed development, and the risk of flooding, to be taken to ensure that the site can be taken forward safely. PPS25 has put into place the ‘Exception Test’ for this purpose. Clause D10 (Appendix D) of PPS25 states: 1. “The Exception Test should be applied by decision-makers only after the Sequential Test has been applied and when ‘more vulnerable’ development and ‘essential infrastructure’ cannot be located in Zones 1 or 2 and ‘highly vulnerable’ development cannot be located in Zone 1.

2. The Exception Test should not be used to justify ‘highly vulnerable’ development in Flood Zone 3a, or ‘less vulnerable’; ‘more vulnerable’; and ‘highly vulnerable’ development in Flood Zone 3b.”

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To meet the requirements of the Exception Test, it must be demonstrated that: a. that the development provides wider sustainability benefits to the community that outweigh flood risk;

b. the development should be on developable8 previously-developed9 land or, if it is not on previously developed land, that there are no reasonable alternative sites on developable previously-developed land; and

c. a FRA must demonstrate that the development will be safe, without increasing flood risk elsewhere, and, where possible, will reduce flood risk overall.

To meet the requirements of point (3) of the Exception Test, a more detailed assessment of flood risk, and how this can be safely mitigated, is required. This is delivered through the development of a Level 2 SFRA at the spatial planning (site allocation) stage, as explained in Section 2. In simple terms, the Level 2 SFRA is intended to ensure that the risk of flooding within the proposed development area is sufficiently well understood to reassure decision makers (and the Environment Agency) that the site can be developed safely in due course.

A detailed site based Flood Risk Assessment (FRA) will be required from the developer at the planning application stage. This is discussed further in Sections 6.3.3 and 7.1.

6.3 Development management

It is vitally important to ensure that the risk of flooding, from all sources, is carefully considered as an integral part of the development management process. PPS25 places a number of specific requirements upon developers, and it is the responsibility of the Council to ensure that these are satisfied before planning permission is given.

Table 1 provides a comprehensive summary of the restrictions placed upon development by PPS25 within areas that are subject to flooding. It also provides a number of recommended minimum design measures that should be sought from developers to ensure that their site (and adjacent areas) will be safe in a flooding situation. This section provides an overview of the specific PPS25 requirements that have informed the population of this development management matrix.

6.3.1 Adopting a Sequential Approach

PPS25 requires a sequential approach to be taken by developers at the planning application stage, and developers will be required to demonstrate that the Sequential Test has been applied in the selection and design of their proposed development site. For allocated sites within the LDF that have been examined as part of the SFRA process, it will only be necessary for developers to apply a sequential approach within the site (i.e. guiding vulnerable land uses to areas of lowest risk within the site boundaries). For all windfall sites, developers will be required to work with the Council to apply the principles of the Sequential Test from a county-wide perspective.

8 Developable sites are defined in Planning Policy Statement 3 (PPS3) Housing as those sites which should be in a suitable location for housing development and there should be a reasonable prospect that the site is available for, and could be developed at the point envisaged 9 Previously-developed land definition (commonly known as Brownfield Land) - see Annex B of Planning Policy Statement 3 Housing

February 2010 Report No. P9514100112-A02 21 Durham County SFRA (Level 1)

6.3.2 Applying the Exception Test

Where a risk of flooding has been identified within a proposed development site, the developer may be required to apply the Exception Test in accordance with PPS25 and Section 6.2.3 above. Those instances in which the application of the Exception Test will be necessary are set out clearly in Table D.3 (Appendix D) of PPS25, and Figure 9 of this report.

To meet the requirements of point (3) of the Exception Test, a detailed appraisal of flood risk, and how this can be safely mitigated, is required. This is delivered through the development of a detailed site based Flood Risk Assessment (FRA) at the planning application stage, as explained in the following section.

6.3.3 Flood Risk Assessment

Where a site is situated wholly or partially within Flood Zone 2 (Medium Probability) or Zone 3 (High Probability), or where a site exceeds 1 hectare in area within Zone 1 (Low Probability), a developer will be required to carry out a detailed site based Flood Risk Assessment (FRA) at the planning application stage. The FRA should be undertaken at the earliest possible stage in the design process, providing a detailed assessment of the nature and severity of flood risk within the site, and recommending how this should be mitigated (i.e. informing the conceptual site layout and design). A more detailed discussion of what should be included in a FRA is provided in Section 7.1.

6.3.4 Mitigating the Risk of Flooding through Design

Where a risk of flooding has been identified within a site, it will be necessary to incorporate design measures to ensure that this is mitigated safely. It is also necessary to ensure that the development will not result in any increase in flood risk elsewhere. This may occur through (for example) the blockage of overland flow paths, the loss of floodplain storage, or increasing the rate and/or volume of runoff from the site.

A number of recommended design measures have been provided in Table 1 below. These are typically sought by the Environment Agency10 as the minimum requirements for proposed development within a flood affected area. Further explanation as to the basis of these recommendations, and how these should be implemented, is provided in Section 7.

It is important to recognise that, in some instances, the adoption of these design measures may conflict with other planning or policy constraints. For example, the substantial raising of floor levels above the flood level may prevent disabled access, or may raise a roof line within a designated character area. In these instances, it will be important for the developer to enter into discussions with the Council and the Environment Agency at an early stage to agree a more suitable means of mitigating the risk of flooding to their proposed development.

10 Guided by recommendations set out within PPS25 and other industry best practice guidance

February 2010 Report No. P9514100112-A02 22 Development within PPS25 Flood Zone

Zone 3a Design Consideration SFRA Reference Zone 3b Zone 2 Zone 1 Areas that are provided a degree of protection against flooding Natural floodplain areas without flood defences from Formal Flood Defences

The Sequential Test must be applied for all sites. Where a site has been allocated within the LDF, then no further action is required. For all windfall sites, the developer will need to laise with the Council to apply the principles of the Sequential Test from a county-wide Sequential Test Section 7.3 (1) perspective.

Essential Infastructure, Water Compatible, Less Vulnernable & Only Water Compatible uses are permitted in Zone 3b. Essential Only Water Compatible & Less Vulnernable uses are permitted in Zone 3a. Essential Infrastructure & More Vulnerable uses may be More Vulnerable uses are permitted in Zone 2. Highly Vulnerable Permissible Land Use Section 7.3 (2) Infrastructure may be considered following the application of the There are no PPS25 restrictions upon land use in Zone 1. considered following the application of the Exception Test. uses may be considered following the application of the Exception Exception Test. Test.

The Exception Test must be applied for Essential Infrastructure The Exception Test must be applied for Highly Vulnerable Exception Test Section 6.3.2 The Exception Test must be applied for Essential Infrastructure & More Vulnerable development in Zone 3a. There is no requirement to apply the Exception Test in Zone 1. development in Zone 3b. development in Zone 2.

A detailed site-based FRA is required for all sites greater than 1ha Flood Risk Assessment (FRA) Section 7.1 A detailed site-based FRA is required for all sites in Zone 3b. A detailed site-based FRA is required for all sites in Zone 3a. A detailed site-based FRA is required for all sites in Zone 2. in area in Zone 1.

The depth and speed of floodwater into the site as a result of defence overtopping and/or breach should be considered to Flood Defence Failure (Hazard) Section 5.8 n/a n/a evaluate site safety, in accordance with FD2320 (Defra, 2005). The n/a n/a long term maintenance & structural integrity of the defences will need to be assured.

Buildings should be avoided within Zone 3b. Where included as Building floor levels should be set a minimum of 600mm above the part of an Essential Infrastructure or Water Compatible 1% (1 in 100) river flood level in Zone 3a, including an allowance Building floor levels should be set a minimum of 600mm above the There are no requirements to raise floor levels within Zone 1. development, buildings should be designed to flood, thereby for climate change. Discussions should be established with the 1% (1 in 100) river flood level, including an allowance for climate Building floor levels within Zone 2 should be set a minimum of Careful consideration of the potential risk of surface water and/or minimising any potential increase in flood levels elsewhere. Council at an early stage to identify any potential constraints to Floor Levels Section 7.4 (1) change. Within defended areas, this flood level should be 600mm above the 1% (1 in 100) river flood level, including an groundwater flooding is required however, and buildings should be Building resilience is paramount in these situations (see Section 7.4 floor raising, including (for example) disabled access or heritage determined assuming the overtopping and/or breach of the flood allowance for climate change. designed to ensure that the risk of flood damage to the building (3) of this report) and the safe evacuation of tenants from the site restrictions. In these circumstances, building resilience measures defences, whichever represents the 'worst' design case. fabric is minimised. during flooding conditions must be assured (see 'Site Access' should be adopted (see Section 7.4(3) of this report) to minimise below). the damage caused to the building by flooding.

Developers should, wherever possible, design their drainage systems so that the volume and rate of runoff from the site does not exceed the greenfield runoff rate. Where this is not feasible, the volume and rate of runoff from the site should (as a minimum) not exceed the existing runoff characteristics of the site. Sustainable Drainage Systems (SUDS) should be used, seeking the most sustainable approach possible (see Figure 12) given the site conditions (see Section 7.5.3). The long term maintenance of the adopted SUDS system will Site Drainage Section 7.5 need to be agreed in liaison with the Council and/or Northumbrian Water. The site drainage system should have a minimum design capacity of 0.33% (1 in 30), however developers should design their site to ensure that runoff that exceeds this capacity (up to the 1% (1 in 100) storm) is controlled within the site, without causing damage and/or harm, and without increasing the risk of flooding to adjacent properties.

Site Layout Section 7.3 (3) Developers should arrange their site to orient the most vulnerable land uses within areas of lowest flood risk (within the site). Buildings and landscaping should be oriented to avoid truncating overland flow paths.

The safety of individuals during a flood is of paramount A dry route of escape, above the 1% (1 in 100) flood level including A dry route of escape, above the 1% (1 in 100) flood level including importance. In Zone 3b, the provision of a dry (or safe) access climate change, should be provided for More Vulnerable Within defended areas of Zone 3a, it will be necessary to ensure climate change, should be provided for Highly Vulnerable There are no access restrictions for sites within Zone 1. Careful route during flooding conditions may not be possible in some development in Zone 3a. For all other land uses, it will be that the route of access is 'safe' in flooding conditions, and this development in Zone 2. For all other land uses, it will be necessary consideration of surface water and/or groundwater flood risks is Site Access Section 7.6 instances. For this reason, it will be necessary to ensure that there necessary to ensure that the route of access is 'safe' in flooding should be assessed in accordance with Section 22 'Flood Risks to to ensure that the route of access is 'safe' in flooding conditions, required however to ensure that safe access will not be is a clear Evacuation Plan in place (see 'Evacuation Plan' below) to conditions, and this should be assessed in accordance with Section People Calculator', FD2320 (Defra, 2005). and this should be assessed in accordance with Section 22 'Flood compromised during a local flooding situation. safely evacuate the site when flooding is anticipated. 22 'Flood Risks to People Calculator', FD2320 (Defra, 2005). Risks to People Calculator', FD2320 (Defra, 2005).

For all sites within Zone 3b, tenants should be encouraged to sign For all sites within Zone 3a, tenants should be encouraged to sign up to Floodline Warnings Direct service where available (see Figure up to Floodline Warnings Direct service where available (see Figure 4). An Evacuation Plan should be prepared for larger commercial developments, providing clear triggers for action as a flood event There is no requirement for an Evacuation or Flood Plan within There is no requirement for an Evacuation or Flood Plan within Evacuation (Flood) Plan Section 7.7 4). An Evacuation Plan should be prepared for the site, providing escalates. This should be proactively communicated to all site tenants. Residents & business owners should be encouraged to prepare Zone 2. Zone 1. clear triggers for action as a flood event escalates. This should be a Flood Plan, setting out what they should do & where help can be found during a flood event. proactively communicated to all site tenants.

Sites that are situated immediately adjacent to a watercourse have particular rights & responsibilities that are outlined in the Environment Agency publication "Living on the Edge". Developers will be required to provide a minimum buffer of 8m from the top of bank to Adjacent to Rivers Section 6.1 (Landowners) allow access by the Environment Agency to the river for maintenance purposes.

TABLE 1 Recommended Design Measures Durham County SFRA (Level 1) Durham County SFRA (Level 1)

6.4 Emergency Planning

Durham County Council has a statutory responsibility under the Civil Contingencies Act 2004 to work collaboratively with partners to assess potential risks, and respond to emergency situations within the County. The County Durham and Darlington Local Resilience Forum (LRF) has been established to ensure that these obligations are met.

A Multi Agency Flood Plan was published by the County Durham and Darlington Local Resilience Forum in April 2009. The plan identifies those areas within the County that are susceptible to flooding, and evaluates the degree of vulnerability of the local community that will be affected. Using this information, the plan sets out how and when an emergency response should be provided as floodwaters rise.

A thorough review of the risks posed by flooding, from all sources (including surface water and groundwater) has been undertaken as part of this SFRA. The SFRA is a ‘living document’, as explained in Section 9, and should be reviewed on a regular basis to ensure that it represents the best available information. Future flooding incidents, and further investment in predictive modeling by the Environment Agency, will provide a continuous improvement in our understanding of flood risks throughout the County.

It is important that, as this appreciation of flood risk changes and improves over time, that this is communicated to the Local Resilience Forum, and the Multi-Agency Flood Plan is updated accordingly.

February 2010 Report No. P9514100112-A02 24 Durham County SFRA (Level 1)

7.0 MITIGATING THE RISK OF FLOODING THROUGH DEVELOPMENT

7.1 The Flood Risk Assessment (FRA)

A detailed site based Flood Risk Assessment (FRA) will be required for all proposed development sites that are situated either wholly or partially within Flood Zone 2 (Medium Probability) or Flood Zone 3 (High Probability), or greater than 1ha in area within Flood Zone 1 (Low Probability). The FRA must be submitted as part of the planning application, and should be undertaken at the earliest possible stage in the design process to inform the conceptual layout and design of the site.

The level of detail required within the FRA will be heavily dependent upon the nature and severity of the flood risk within the proposed development, and the land use that is being considered for the site. This is described in Chapter 3 of the PPS25 Practice Guide, specifically Figure 3.5 of the guidance that sets out the Level 1 (Screening), Level 2 (Scoping) and Level 3 (Detailed) phases of the FRA delivery process. In sites within which the risk of flooding is minor, and the drainage system can be designed in such a way to ensure that there is no increase in runoff from the site, a Level 1 Screening Study is all that will be required.

Figure 3.5 of the PPS25 Practice Guide is duplicated in Figure 10 below for reference purposes.

Figure 10 Levels of detail for a site based FRA Figure 3.5, PPS25 Practice Guide (June 2008)

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Guidance is provided in Appendix C of the PPS25 Practice Guide as to what should be contained with the FRA report, and how the report should be structured. The basic structure and content of the FRA should be set out broadly in accordance with the following. Further explanatory guidance notes are provided within the PPS25 Practice Guide (Appendix C). 1. Development description & location Z What type of development is proposed and where will it be located? Z What is its vulnerability classification? Z Is the proposed development consistent with the Local Development Documents? Z Provide evidence that the Sequential Test, and where necessary the Exception Test, has been applied in the selection of this site for this development type? 2. Definition of the flood hazard Z What sources of flooding could affect the site? Are there existing formal or informal defences11 that protect the site from flooding, and what is the consequence should these overtop or breach? Z For each identified source, describe how flooding would occur, with reference to any historic records wherever these are available. Z What are the existing surface water drainage arrangements for the site? 3. Probability Z Which flood zone is the site within? Z If there is a Strategic Flood Risk Assessment (SFRA) covering this site, what does it show? Z What is the probability of the site flooding taking account of the contents of the SFRA and of any further site-specific assessment? Z What are the existing rates and volumes of run-off generated by the site? 4. Climate change Z How is flood risk at the site likely to be affected by climate change? 5. Detailed development proposals Z Provide details of the development layout, referring to the relevant drawings. Z Where appropriate, demonstrate how land uses most sensitive to flood damage have been placed in areas within the site that are at least risk of flooding. 6. Flood risk management measures Z How will the site be protected from flooding, including the potential impacts of climate change, over the development’s lifetime? 7. Off site impacts Z How will you ensure that your proposed development and the measures to protect your site from flooding will not increase flood risk elsewhere? Z How will you prevent run-off from the completed development causing an impact elsewhere? 8. Residual risks Z What flood-related risks will remain after you have implemented the measures to protect the site from flooding? Z How, and by whom, will these risks be managed over the lifetime of the development?

It is strongly recommended that the developer opens discussion with the Council and the Environment Agency as early as possible to agree the scope of the FRA required for the specific site that is under consideration. The Council and the Environment Agency will often also be able to provide (at a cost) useful information relating to the risk of flooding within the site.

The Environment Agency offers some useful standing advice for developers on its website, including contact details, some basic technical advice, and linkages to useful reference documents. The Environment Agency standing advice can be found at http://www.environment-agency.gov.uk/research/planning/82587.aspx.

11 Refer Section 5.8 for a description of ‘formal’ and ‘informal’ defences

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7.2 Data Sources for Developers

A considerable amount of useful information has been collated as part of this SFRA, and developers should make use of this when preparing their detailed site-based Flood Risk Assessment. To assist in this regard, Table 2 provides a summary of the type of information that may be sought as part of the FRA process, and where relevant guidance and/or local data is provided within this Level 1 SFRA.

Area of Interest SFRA Reference

Historical Flooding Section 4.1 & Appendix A

Topography Section 5.1, Figure 5 & Appendix L

Geology Section 5.1 & Figure 6

Surface Water Flood Risks Section 5.5, Appendix M & Appendix L

Section 5.3, Section 5.4, Appendix B & Fluvial (River) & Tidal Flood Risks Appendix L

Residual Risk of Flooding (Flood Section 5.7, Section 5.8 & Figure 7 Defences & Reservoirs)

SUDS Section 7.5 & Appendix I

Flood Risk Assessment Section 7.1

Climate Change Section 5.9 & Appendix K

Design Considerations for Development Sections 7.3 to 7.7 & Table 1 in a Flood Affected Area

Table 2 SFRA References to Useful Information for Developers

7.3 Site Selection & Site Layout (A Sequential Approach)

The sequential approach should be applied by developers when selecting a site for development, when considering the type of land use that will be put forward for the site, and when developing the conceptual design for the site (i.e. the site layout). This is explained further below:

1. Site Selection

Developers are required to demonstrate that the Sequential Test has been applied in the selection of their proposed development site. For allocated sites within the LDF that have been examined as part of the SFRA process, reference to the SFRA can be made within the FRA, and no further action will be necessary. For windfall sites, developers will be required to work with the Council to apply the principles of the Sequential Test from a county-wide perspective. The Sequential Test is described in Section 6.2.2 of this report.

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2. Land Use

Developers are required to comply with the permissible land uses set out in Table D.3 of PPS25. These are described in Section 6.2 of this report. For example, residential development should not be considered within Zone 3b Functional Floodplain, reflecting the relatively high risk that flooding poses to homes and individuals within these areas. Within Zone 3a High Probability, residential development may only be considered further following the application of the Sequential Test, i.e. demonstrating that there are no suitable sites available within a lower risk zone. In these circumstances, the Exception Test will need to be applied, as explained in Section 6.2.3.

3. Site Layout

Once a site has been selected following the application of the Sequential Test, the developer should apply the principles of the sequential approach within the boundaries of their site. This will assist them to orient the development in such a way as to minimise the potential risk of damage to buildings, disruption to tenants, and/or harm to individuals should a flood event occur. For example:

Z within mixed use developments, vulnerable land uses (e.g. housing) should be directed towards more elevated areas of the site that are at lowest risk of flooding, or raised above the commercial uses;

Z buildings should be oriented within the site to avoid truncating overland flow paths, which may result in an increase in flood levels elsewhere;

Z landscaping and roads within the site should be oriented and designed to cater for excess runoff that may be experienced following periods of particularly heavy rainfall in which the drainage system will be over-whelmed, avoiding uncontrolled runoff through the site;

Z access routes should be oriented and designed to ensure that there is always (local conditions permitting during an emergency situation) a safe route of escape for tenant of the site, as explained in Section 7.6.

7.4 Building Design

The PPS25 Practice Guide advocates a hierarchy of flood risk management for development, as presented described in Section 3 and Figure 3 of this report. These same principles should be adopted by developers when designing new builds, and/or refurbishing existing buildings. It is worth highlighting that many of the principles outlined below may also be adopted by existing property owners, assisting them to reduce the impact that flooding has upon their home or business.

Detailed guidance is provided in the Communities and Local Government (CLG) publication entitled “Improving the flood performance of new buildings - Flood resilient construction” (May 2007). Three tiers of flood risk management design solutions are provided for developers and property owners, and these are outlined below in hierarchical order.

1. Avoidance Avoidance measures include: Z Not building in flood risk areas wherever possible

Z Raising ground or floor level or re-designing to a location outside the flood area, and provision of replacement storage.

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Z Local bunds can be designed to protect individual or groups of buildings from flooding. It is unlikely that these can be made fully watertight and pumps may be necessary to remove or re- direct any seepage water within the protected area. Bunds may be effective where the predicted duration and depth of flooding is low. Advice should be sought from a Qualified Engineer/Professional to ensure the bunds can withstand predicted water pressures.

Z Landscaping of a development site or building curtilage to direct or divert floodwater away from buildings can be effective particularly where the predicted duration of flooding is short i.e. hours rather than days. Landscaping is an integral component of sustainable drainage systems (SUDS). They can be designed to manage flood risk and water quality, and also environmentally acceptable to communities.

Z Boundary walls and fencing could be designed with high water resistance materials and/or effective seals to minimise water penetration for low depth, short duration floods (but not for groundwater flooding).

2. Resistance Resistance is defined as measures taken at building level to prevent floodwater entering the building and damaging its fabric. For example, these measures can include the use of materials with low permeability. Resistance measures are aimed at preventing floodwater ingress into a building; they are designed to minimise the impact of floodwaters directly affecting buildings and to give occupants more time to relocate ground floor contents. They will probably only be effective for short duration, low depth flooding i.e. less than 0.3m. They include the use of low permeability materials that reduce the rate of water ingress into a property. Further details on flood resistant construction techniques are provided in Chapter 5 of the CLG guidance.

3. Resilience

Resilience is defined as sustainable measures that can be incorporated into the building fabric, fixtures and fittings to reduce the impact of floodwater on the property. This allows easier drying and cleaning, ensures that the structural integrity of the building is not compromised and reduces the amount of time until the building can be re-occupied.

Resilience measures are either an integral part of the building fabric or are features inside a building. These can be considered in combination with resistance measures or where resistance measures are not an option. In order to decide which resilience measures would be effective it is necessary to know the potential depth and duration of flooding that is likely to occur. Further details on flood resilient construction techniques are provided in Chapter 6 of the CLG guidance.

As explained above, the suitability of the building design measures will be dependant to a large degree on the depth of flooding that is expected to occur within the site. This is depicted in Figure 4.1 of the CLG guidance, providing developers and property owners with a recommended approach where the anticipated flood depth is up to 0.3m, less than 0.6m, and greater than 0.6m respectively. This figure is duplicated in Figure 11 below for reference purposes.

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Figure 11 Recommended Design Approach vs Flood Depth Figure 4.1, Improving the Flood Performance of New Buildings CLG (May 2007)

7.5 Sustainable Drainage Systems (SUDS)

7.5.1 Overview

Sustainable drainage systems (SUDS) are defined by CIRIA12 as “a sequence of management practices and control structures designed to drain surface water in a more sustainable fashion than some conventional techniques.” A considerable wealth of guidance exists to assist developers in the selection, design and implementation of appropriate SUDS. The most comprehensive and widely utilised publication is The SUDS Manual, developed by CIRIA (March 2007). This can be obtained free of charge via the CIRIA website at http://www.ciria.org.uk/suds/index.html. The website also provides some very useful information relating to case studies, training events, and legal considerations that should be taken into account when developing a SUDS solution.

Sustainable drainage systems are being increasingly sought from developers by local authorities and government bodies worldwide. The primary benefit of a SUDS solution is an ability to reduce the rate of runoff from a site, and to reduce the concentration of contaminants including (for example) nutrients and suspended solids in the flow. They can also provide aesthetic and recreational amenities within a development site however, where adopted as an integral element of the site landscape.

12 Construction Industry Research and Information Association (CIRIA)

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7.5.2 SUDS Maintenance

The long term effectiveness of a SUDS drainage solution however is entirely dependent upon the future maintenance of the scheme, and in many countries this has proven to be a cause for concern. Within England, the responsibility for SUDS adoption (and long term maintenance) has been problematic, with debate ongoing as to whether this should fall upon developers, local authorities and/or water companies. There is also a widely held perception that the current ‘right to connect’ within England to some degree removes the onus from developers to consider SUDS as a viable alternative to traditional drainage techniques.

The Draft Floods & Water Bill (2009) has sought to address these areas of uncertainty by introducing clarity in relation to government policy regarding SUDS, in addition to the roles & responsibilities that must be taken regarding long term maintenance. The draft Bill states: “The Bill will require developers to include sustainable drainage, where practicable, in new developments, built to standards which reduce flood damage and improve water quality. It will also amend section 106 of the Water Industry Act 1991 to make the right to connect surface water run-off to public sewers conditional on meeting the new standards. It will give responsibility for approving sustainable drainage systems in new development, and adopting and maintaining them where they affect more than one property, to a SUDS approving body, generally local authorities.”

In the immediate short term, CIRIA has developed a series of model agreements that can be used by local authorities to establish the means by which the ongoing maintenance of a SUDS system will be carried out. These are provided on the CIRIA website at http://www.ciria.org.uk/suds/icop.htm and include three ‘modes’ of arrangement, namely: Z Planning obligation - incorporating SUDS provisions Implementation and maintenance of SUDS, either as a planning obligation under Section 106 of the Town and Country Planning Act (1990), or as a condition attached to planning permission (i.e. responsibility for maintenance taken by developer)

Z SUDS maintenance framework agreement Legal framework that defines which body takes over and maintains the SUDS (i.e. responsibility for maintenance taken by local authority, or other)

Z Model discharge agreement A model deed in relation to owners of SUDS facilities granting sewerage undertakers rights in perpetuity to discharge, flood and maintain in default (i.e. responsibility for maintenance taken by Northumbrian Water)

There is relatively little published information relating to the long term costs associated with SUDS maintenance, particularly within the UK. Useful research has been ongoing within the US however, and this has been reviewed to provide some helpful background information for SFRA purposes. The Water Environment Research Foundation (WERF), co-funded by UK Water Industry Research, has published a paper relating to the whole-life costs of SUDS techniques. They have concluded13:

13 Extract from WERF website www.werf.org

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“In many jurisdictions vegetation management dominated the maintenance activities rather than sediment, debris, and trash removal or structural repair. Research indicated that major drivers of most budgets were not technically based, but rather aesthetically based. Communities were more likely to fund maintenance to improve a system’s appearance than to improve its functionality.

This study also showed that design and operation of SUDS must consider the damage that inevitably arises when construction stage runoff is permitted to enter systems. The research team encountered repeated instances where high sediment loads associated with construction activities had caused almost irreparable damage to downstream SUDS, especially those relying on an infiltration component.

The researchers determined that numerous problems and costs can be avoided by using an adequate inspection program. In addition, agencies consistently agreed that lack of routine maintenance leads to greater long-term expenses.”

Annual maintenance costs for a relatively small number of SUDS installations were collated as part of the WERF research program, and these are summarised in Table 3 below for reference purposes. It is important to highlight that there are a large number of locally specific factors that will influence maintenance costs, including (for example) accessibility and local ground conditions. These provide an ‘order of magnitude’ indication of the costs that may be incurred however.

Indicative Annual Maintenance SUDS Technique Cost (£) for Sediment Removal & Re-vegetation

Grassed Swales £250

Filter Strips & Green Roofs £650

Large Retention Ponds £18,500

Engineering Solutions (Sediment Traps) £1050 NOTE: Costs are based upon collated WERF research (US based), inflated to 2009 figures & converted to GBP

Table 3 Indicative Annual Maintenance Costs for SUDS

7.5.3 SUDS Approaches

A number of SUDS ‘types’ are available for application within a site, and it is vitally important that careful consideration is given to the local conditions when selecting a SUDS approach. This is described in Section 7.5.3 below. To assist in the selection process however, the Environment Agency has developed a SUDS ‘hierarchy’ that they recommend for use by developers when considering the design alternatives that are available to them. This is set out in Figure 12 below, providing an outline of the benefits that can be achieved by each technique.

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Figure 12 Hierarchy of SUDS Techniques (Environment Agency)

An overview of each available SUDS technique is provided in the Environment Agency’s publication Sustainable Drainage Systems – A Guide for Developers, and this has been included as Appendix I of this report for reference purposes.

7.5.4 The Application of SUDS in County Durham

There are a number of very important design considerations that must be taken into account when selecting a SUDS approach. These are described in Table 5.3 of the CIRIA SUDS Manual, and outlined below: Z Soils. Infiltration techniques rely on a permeable soil layer, and are unsuitable in impermeable areas (e.g. clay). In contrast, ponds and wetlands rely on water ponding in the facility for a minimum retention time, and this will only be achieved in an area of permeable soils if a lining is installed.

Z Groundwater. Infiltration techniques rely on an ability to freely drain runoff into the underlying soils. They may also however allow the passage of groundwater to the surface, exacerbating groundwater flooding. The CIRIA SUDS Manual recommends that at least 1m of soil depth is available between the base of the SUDS facility and the maximum predicted groundwater level.

Z Topography. SUDS techniques that rely upon the capture, retention and infiltration of runoff are likely to be unsuitable in steeper areas. It may be feasible to orient infiltration trenches or swales so that they are perpendicular to the slope. Care must be taken to avoid soil saturation in this design scenario however, as this may result in slope instability.

Z SUDS Catchment Area. The effectiveness of a SUDS technique may be compromised if they are relied upon to drain (treat) an area that exceeds their design capacity. The CIRIA SUDS Manual indicates that SUDS devices that rely upon vegetation and/or infiltration to reduce the concentration of contaminants in the flow are generally suitable for small catchment areas, but are likely to be over- whelmed (or ‘drowned’) by larger flow volumes. In contrast, a pond that relies purely on the retention time of water within the system is likely to be more suitable for larger catchment areas.

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Z Space Availability. The availability of space within a proposed development site will be an important consideration when developing the SUDS design. It is for this reason that developers are very strongly encouraged to consider the implementation of SUDS at the earliest possible stage in the design process.

The latter two design considerations are very locally specific, and can only be considered sensibly at a site scale. Topography, groundwater and geology are design issues that can be considered strategically however, and further guidance has been provided in Appendix L on this basis to indicate broadly which SUDS techniques may or may not be suitable across the County. It is highlighted that the SFRA advice provided has been established on the basis of very broad scale information, and this must be thoroughly reviewed on a site-by-site basis as part of the design process.

7.6 Safe Site Access

Within areas at risk of flooding, it is accepted that it may not be possible to fully remove the potential likelihood that a flood will occur. As a result, it is essential to ensure that tenants within the site will be safe when the inevitable happens.

Forewarning that a flood is expected to occur, and forward planning to ensure that tenants within the site know how to respond appropriately to the warning received, is imperative. These are discussed in Section 7.7. Of equal importance however is the provision of a safe evacuation route in a flooding situation. This is a very important design consideration for the developer.

Where a development is situated within an area at risk of flooding, or indeed where the development may be above flood level but will be encircled by floodwaters (i.e. situated on a ‘dry island’), it is necessary for the developer to ensure that the site can be evacuated safely during a flood event. For design purposes, the Environment Agency recommends that safe access is assured the 1% (1 in 100) design event, including an allowance for climate change.

Some subjectivity surrounds what is meant by ‘safe’ in these circumstances. To assist developers however, the Environment Agency has issued the following guidance. It is recommended that this is applied in the first instance during the conceptual development design stage. Discussions should be held with the Council and the Environment Agency at an early stage should it become evident that these design conditions cannot be met due to physical constraints within (or surrounding) the site. A. Developments within Zone 3a High Probability and Zone 2 Medium Probability that are not offered protection from flood defences: Z Dry escape, above the 1% (1 in 100) design flood level, taking into account climate change, should be provided for all ‘more vulnerable’ and ‘highly vulnerable’ development; Z ‘Safe' should preferably be dry for all other uses such as educational establishments, hotels and 'less vulnerable' land use classifications.

B. Developments within Zone 3a High Probability and Zone 2 Medium Probability that are offered protection from flood defences: Z 'Safe' access should preferably be dry for ‘highly vulnerable’ uses; Z 'Safe' access should incorporate the ability to escape to levels above the predicted flood level, assuming a breach of the flood defences.

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C. For major developments, ‘safety’ will also need to be ensured through the development of a robust evacuation plan. This should clearly define routes to dry land. This may include routes through flood waters, providing the depth and speed of flow across the evacuation route are below the risk defined by the “danger to some” threshold in “Flood Risk Assessment Guidance for New Development (Phase 2), Framework and Guidance for Assessing and Managing Flood Risk for New Development – Full Documentation and Tools, R&D Technical Report FD2320/TR2” (Defra, October 2005)14.

It is important to recognise that these design principles consider the risk of flooding in isolation. In a ‘real’ emergency situation, it is fair to assume that other hazards may arise that may also pose a potential risk of harm. For this reason, it is essential that the instructions of the emergency services are adhered to (where given) during an emergency flooding situation. In some circumstances, it may be necessary to divert evacuation of a site away from the ‘designed’ access route due to hazards that have arisen unexpectedly at that location.

7.7 Flood Warning, Planning and Preparation

It is important to raise awareness within the local community, assisting them to understand more fully the risks that flooding may pose to them, and providing them with the knowledge and tools that will enable them to react efficiently and effectively should a flood occur.

7.7.1 Flood Warning

The Environment Agency makes flood warnings available to properties at risk of river flooding along the River Wear and River Tees, as depicted in Figure 4. A minimum of 2 hours forewarning of a flooding event is offered wherever possible, however this cannot always be assured. It is important to recognise that flood warnings can only be provided to those property owners and tenants that have signed up to the Environment Agency’s Floodline Warnings Direct service. 7.7.2 Evacuation Plan (Developers & Site Operators)

Developers (and/or site operators) are required to prepare an evacuation plan for major developments that they are proposing. These may include (for example) large commercial precincts, major infrastructure facilities, or an office complex. The evacuation plan should set out responsibilities for monitoring and communicating flood warnings, and clear triggers for action within the site. The evacuation plan should be regularly reviewed and updated where necessary, and must be proactively communicated to tenants within the site. It is recommended that practice drills are undertaken periodically to maintain awareness of the potential flood risk. 7.7.3 Flood Plan (Residents & Businesses)

For individual property owners that are situated within (or circulated by) an area that is at risk of flooding, forward planning and preparation can reduce the damage and danger that is suffered during a flood event. The Environment Agency recommend that residents and businesses develop a Flood Plan, setting out what to do and who to contact as a flood event unfolds. Helpful advice is provided on the Environment Agency’s website at http://www.environment-agency.gov.uk/homeandleisure/floods/31640.aspx.

14 Commonly referred to as FD2320

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8.0 CONCLUSIONS

The risk of flooding from rivers, the sea, surface water and groundwater has been interrogated as part of this investigation, providing an overview of flood risks from all potential sources in accordance with PPS25 and the PPS25 Practice Guide.

It is necessary for Durham County Council to exercise informed decision making when establishing the county-wide Local Development Framework and targeted Area Action Plans, adopting a sequential approach to the allocation of land for future development and regeneration. At the planning application stage, Council development management officers and developers must also apply a sequential approach, seeking to ensure that vulnerable development is not placed at unnecessary risk. Finally, Council emergency planning officers should make the Local Resilience Forum aware of the risks that have been identified within this SFRA, ensuring that the Multi-Agency Flood Plan reflects the best available information with respect to flood risks within the County.

A considerable amount of flooding related information has been compiled in the development of this SFRA, providing the Council with a valuable resource. It is recommended that the collated mapping and historical flooding information is passed into the ownership of the Council Drainage Department to ensure that it is updated on a regular basis as new information becomes available, and/or flooding incidents occur.

9.0 A LIVING DOCUMENT

The Durham County Level 1 SFRA has been prepared in accordance with PPS25 (December 2006) and the PPS25 Practice Guide (June 2008), on the basis of the best information in relation to flood risk as of September 2009. Investment will continue to be placed by the Council and the Environment Agency into improving our understanding of flood risks within the County. Floods may also be experienced, and this may alter our appreciation of flood risk in some areas. Legislation may also change over time.

For this reason, it is important to recognise that this SFRA is intended to be a living document. It is recommended that the Council carry out a cursory review of the legislative and technical factors that may influence the findings and recommendations of the SFRA on an annual basis. If necessary, the SFRA should be reviewed. A list of suggested SFRA review questions is provided in Appendix N to assist in this regard.

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Report Signature Page

GOLDER ASSOCIATES (UK) LTD.

Max Tant Karen Dingley Senior Hydrologist UK Surface Water Manager

Company Registered in England No.1125149 At Attenborough House, Browns Lane Business Park, Stanton-on-the-Wolds, Nottinghamshire NG12 5BL VAT No. 209 0084 92

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APPENDIX A Historical Flooding Incidents

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APPENDIX B SFRA Flood Maps (PPS25)

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APPENDIX C The Policy Framework

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National Policy

Planning Policy Statement 25: Development and Flood Risk

Planning Policy Statement 25 (PPS25) was published in December 2006 and sets out the planning objectives for flood risk management. It states that all forms of flooding and their impacts are material planning considerations. The aim of PPS25 is to ensure that flood risk is taken into account at all stages of the planning process to prevent inappropriate development in ‘at risk’ areas, and to mitigate the risk of flooding effectively where development is permitted in flood affected areas.

The key objectives for planning are appraising, managing and reducing flood risk.

Z To appraise the risk it is stated that flood risk areas need to be identified, and that the level of risk needs to be defined. To facilitate this, PPS25 indicates that Regional Flood Risk Appraisals and Strategic Flood Risk Assessments should be prepared.

Z To manage the risk, Local Planning Authorities (LPAs) need to develop policies which “avoid flood risk to people and property where possible, and manage any residual risk, taking account of the impacts of climate change”. LPAs should also only permit development in flood risk areas if there are no feasible alternatives located in areas of lower flood risk.

Z To reduce the risk, PPS25 indicates that land needed for current or future flood management should be safeguarded; new development should have an appropriate location, layout and design and incorporate sustainable drainage systems (SUDS); and that new development should be seen as an opportunity to reduce the causes and impacts of flooding by measures such as provision of flood storage, use of SUDS, and recreating the functional flood plain.

A partnership approach is stressed in PPS25 to ensure that LPAs work with partners such as the Environment Agency. The Environment Agency can provide both information and advice relating to flood risk, and should always be consulted when preparing policy or making decisions which will have an impact on flood risk.

The future impacts of climate change are highlighted, as climate change will lead to increased flood risk in many places in the years ahead. When developing planning policy, LPAs need to consider if it is necessary to encourage the relocation of existing development to locations at less of a risk from flooding in order to prevent future impacts of flooding.

PPS25 also gives specific advice for determining planning applications, which should be reflected when developing policy. LPAs should ensure that flood risk assessments (FRAs) are submitted with planning applications; they should apply the sequential approach, which ensures that lower risk areas are considered preferable to higher risk areas; priority should be given to the use of SUDS; and new development should be designed to be resilient to flooding as appropriate.

The PPS25 Practice Guide was published in June 2008, providing additional guidance on the implementation of the principles set out in PPS25.

Planning and Climate Change – A Supplement to Planning Policy Statement PPS1

This document was published by the Government in December 2007. It highlights the issue of climate change and details ways planning should prepare for its effects, which includes managing flood risk. This set out proposals for how spatial planning should contribute to reducing emissions and stabilising climate change (mitigation) and take into account the unavoidable consequences (adaptation).

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Regional Planning Policy

The North East of England Plan

The North East of England Plan, the revised Regional Spatial Strategy (RSS) for the region, was published on 15 July 2008. The RSS forms part of the Statutory Development Plan which covers and is relevant to the Durham County Council area. It is important to note that the County Council is a Unitary Authority established in April 2009 and covers the County Durham area that previously had a two tier structure of local government comprising the former County Council and seven district level councils (Chester-le-Street, Derwentside, Durham City, Easington, Sedgefield, Wear Valley and Teesdale).

This document includes a number of policies relevant to flood risk in the region within which Durham County is situated and these are outlined below.

Policy 2 - Sustainable Development

This set out that planning proposals and Local Development Frameworks should support sustainable development by pursing a number of objectives, including protecting and enhancing the quality of the Region’s ground, river and sea water, to mitigate environmental and social costs of developments, and encourage efficient resource use and to prevent inappropriate development in flood plains: j. to reclaim and reuse derelict land to make more productive use of land; k. to protect and enhance the Region’s cultural heritage and diversity; and l. to promote the concept of green infrastructure, a network of linked, multifunctional green space in and around the Region’s towns and cities;

Clause 2.2 Social Objectives a. to tackle the social, economic and environmental impacts of multiple deprivation; b. to raise educational achievement across the Region and improve the skills of the workforce and of adults who are currently economically inactive, through training and skill development; c. to ensure everyone has the opportunity of living in a decent and affordable home; d. to improve the quality and choice of housing through market renewal and new development; e. to reduce crime and the fear of crime, particularly through good design; f. to improve health and well-being while reducing inequalities in health; g. to ensure good accessibility for all to jobs, facilities, goods and services in the Region particularly by public transport, walking and cycling; h. to reduce the need to travel by private car; and i. to increase public involvement in decision-making and civic activity;

The RSS recognises that climate change is the single most significant issue that affects global society in the 21st Century. The challenge is seen to be to adapt to the impacts that will result from climate change. This adaptation will include measures to help the region cope with potential climate change which may include changes in development layout and building design, and Sustainable Urban Drainage Systems (SUDS) to mitigate against changing rainfall patterns. Natural systems and habitat networks also play an important part in adapting to the consequences of climate change. The regions peatlands are cited as a vital resource, acting as both carbon store and mitigating the effects of heavy rainfall, by reducing the rate of runoff in catchments and the intensity of flood events thereby protecting people, homes and businesses.

. Policy 3 - Climate Change

This details that all strategies, plans and programmes in the Region shall contribute to mitigating climate change and assisting adaptation to the impacts of a changing climate by a range of measures including:

1. Integrating climate change considerations into all spatial planning concerns, including housing, economic growth and regeneration, water supply and sustainable drainage.

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2. Planning for the successful adaptation to the impacts of climate change in the Region by: a. locating and designing new development for the climate, and climatic impacts, it is likely to experience over its intended lifetime; b. considering the desirability of avoiding new development in those areas likely to be vulnerable to the impacts of climate change, particularly in situations where measures to provide resilience are not viable. Options should be brought forward for adapting existing development in areas that are, or are likely to become, vulnerable to such impacts; c. taking into account and assisting adaptation to the impact of climate changes on the natural environment, ecosystems and biodiversity, agriculture, water resources, economic activities, transport, built environment and energy supply; d. maximising opportunities from positive impacts of climate change in the Region.

Policy 4 - The Sequential Approach To Development

Local Development Frameworks are required to adopt a sequential approach to the identification of land for development to give priority to the most sustainable locations. All sites should be in locations that avoid areas at the highest risk from flooding, having particular regard to the vulnerability of the proposed development to flooding.

Policy 28 - Gross and Net Dwelling Provision

This details the total dwelling construction that Local Development Frameworks should make provision for. The table below sets out the following average annual level of total dwelling construction in the period 2004- 2021.

Gross Dwelling 2004-11 2011-16 2016-21 2004-21 Provision

Durham 1890 1620 1225 1615

Replacement 220 285 190 230

Demolition 355 360 145 295

These figures are further broken down into pre April 2009 council boundaries.

The RSS is also concerned with groundwater, in relation to pollution, ecology and Sustainable Drainage Systems. Paragraph 3.142 sets out that in addition to the importance of the Region’s coast and rivers, the Region’s groundwater resources are also significant and can be vulnerable to pollution. It also states that development incorporating conventional drainage techniques can result in increased flood risk. It states that Sustainable Drainage Systems (SUDS) provide a range of techniques to minimise the adverse effects of development and to enhance biodiversity through good drainage design and practice. However, there will be certain circumstances in which the use of SUDS techniques may not be appropriate, for example, where proposed development will lie over an important aquifer.

Policy 34 - The Aquatic & Marine Environment

This sets out that “Strategies, plans and programmes, and planning proposals should: a. ensure that any schemes involving the transfer of water between catchments have consideration to the impacts on environmental and recreational assets of areas both nearby and upstream of the transfer base, particularly in relation to Kielder Water; b. integrate the objectives of emerging and existing plans and strategies which consider the wider management of water bodies, groundwater and coastal / marine areas; c. ensure that the construction and use of new development along river corridors takes account of its potential polluting effects; any opportunities for improvements and conservation of water

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quality; the possibility of flooding onsite and elsewhere along the watercourse; the availability of water resources; biodiversity; the impacts of climate change and the incorporation of necessary adaptation and mitigation measures, and the risk from minewater pollution; d. ensure, where appropriate, that Sustainable Drainage System techniques are adopted; e. set a positive policy framework for delivering plans for Integrated Coastal Zone Management, River Basin Management, Shoreline Management and Catchment Flood Management for the Region’s coastal, estuarine and near-shore zones by adopting an ecosystem based approach to promote the recovery and conservation of marine eco-systems, including designated sites, favouring the evolution of the coast, estuaries and near-shore zones through natural processes wherever possible and seeking to safeguard the conservation of marine heritage features; f. take into account, and where possible plan to ameliorate, the risk of “coastal squeeze” having an impact on internationally designated nature conservation sites; and g. promote appropriate water-based recreational and leisure opportunities, particularly at Kielder Water and along the Region’s coastline”.

The RSS Justification for its flood risk policy (below) sets out that development incorporating conventional drainage techniques can result in increased flood risk. It also mentions that there are Catchment Flood Management Plans, through which the Environment Agency works with other key decision makers to identify and agree policies for sustainable flood risk management.

The RSS sets out some background to its policy on flood risk as follows:

Clause 3.148 “The effects of climate change and factors such as land management and development are having an impact on fluvial and coastal flooding in the Region, as demonstrated by flooding in places including Ponteland and Skinningrove in 2000 and those in Hexham early in 2005. Parts of the Region’s coastal and tidal areas are currently at risk of flooding from the sea, for example the south east Northumberland coast and inland and coastal areas around the tidal river Tees. Elsewhere, the low-lying areas adjacent to rivers such as the Pont, Gaunless, the confluence of the North and South Tyne, middle and upper reaches of the Wear, and the lower reaches of the Tees are at risk from fluvial floods, as are communities close to steep, fast flowing watercourses in narrow valleys. The predictions for climate change and sea level rise in the North East will increase these risks and strategies, plans and programmes will need to take this into account.

Clause 3.149 Flooding from rivers and coastal waters is a natural process that plays an important role in shaping the natural environment. The damage that results to people and property is a consequence of previous human decisions about the location and nature of development and land use. Such damage cannot be prevented entirely, although its effects can be reduced by: reducing development upstream that may increase flooding; encouraging environmental management through the soft engineering of river banks; promoting rivers to find their natural courses; the use of SUDS techniques; the creation of associated riverine wetland areas; planting of trees; and the blocking of grips and dykes in upland moorland and peat bog to retain water and increase the water holding capacity of upland areas.

Clause 3.150 RSS should take a long-term view of coastal evolution and fluvial flooding too, in order to encourage schemes that maintain and restore the dynamic physical environment, and recognise the importance of working with natural processes in adapting to predicted sea level rise. An ecosystem-based approach to marine and coastal management should be promoted that focuses not only on the conservation of existing resources, but also seeks recovery of degraded ecosystems, for example, through managed realignment of sea defences in appropriate locations to allow the re-establishment of inter- tidal salt marsh and mudflats.

Clause 3.151 If flood risk is not to increase over time it is important that Local Development Frameworks identify lowest risk sites for future development. In order to do so local planning authorities will need to identify the spatial variation of flood risk within their areas. These studies are known as Strategic Flood Risk Assessments and are a vital part of a Sustainability Appraisal of an LDF. The preparation of Strategic Flood Risk Assessments

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will enable planning authorities to apply the sequential test to the preparation of strategies, plans and programmes and inform the preparation of flood risk assessments by applicants for planning permission. The RPB, working with the Environment Agency, will produce guidance to assist planning authorities to plan for flood risk within the Region.

Clause 3.152 In parts of the country there has been an increased incidence of local flooding occurring as a result of surface runoff and capacity constraints in drainage systems, possibly linked to changes in rainfall patterns and intensity. This is primarily a matter for local planning, but may need to be taken into account strategically where it is likely to contribute to flooding in combination with fluvial and coastal flood risk.

Clause 3.153 The Environment Agency maintains up-to-date flood risk area information. This information is vital for the preparation of plans and strategies along with Catchment Flood Management Plans; the forthcoming Northumbria River Basin Management Plan; Estuary Management Plans; Shoreline Management Plans; Management Plans for the Region’s Heritage Coasts; the restoration of upland peatlands in the upper reaches of the catchments; and any other emerging and existing plans and strategies which consider the wider management of water bodies and coastal / marine areas.

Clause 3.154 In some circumstances other material considerations may outweigh the flooding issues within identified flood risk areas, for example the significant need for economic and social regeneration and the need to reuse previously developed land. In such circumstances, development will only be permitted where following consultation with the Environment Agency and other relevant organisations, the necessary protection or management measures can and will be provided and are consistent with relevant management plans.

Clause 3.155 Taking account of circumstances within entire catchments, strategies, plans and programmes should identify opportunities to control and manage floodwater. Particular attention should be given to identifying the extent of functional floodplains (the unobstructed or active areas where water regularly flows in times of flood); the potential for the extension of managed washlands (areas of flood plain where water is stored in times of flood); managed realignment and the restoration of floodplains; and the possibilities for multi-functional uses of such land so as to inform development plans and gain effective integrated management of areas at risk from tidal or fluvial flooding.”

Policy 35 - Flood Risk

A. Strategies, plans and programmes should adopt a strategic, integrated, sustainable and proactive approach to catchment management to reduce flood risk within the Region, managing the risk from: a. tidal effects around estuaries and along the coast including the implications of the latest Government predictions for sea level rise; b. fluvial flooding along river corridors and other significant watercourses resulting from c. catchments within and beyond the Region and other sources of flooding; and d. flooding resulting from surface water runoff and capacity constraints in surface water drainage systems.

B. In developing Local Development Frameworks and considering planning proposals, a sequential risk- based approach to development and flooding should be adopted as set out in PPS25. This approach must be informed by Strategic Flood Risk Assessments prepared by planning authorities in liaison with the Environment Agency to inform the application of the Sequential Test and, if necessary, the Exception Test, in development allocations in their LDDs and consideration of planning proposals.

The policies mentioned above will need to be considered when the Unitary Council is considering how to allocate land, in particular, in order to meet development pressures such as the need for additional housing.

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Local Planning Policy

A thorough review and update of local planning policy will be undertaken as part of the LDF process within County Durham, providing an excellent opportunity to ensure that adopted policy is both robust and locally specific. In the intervening period however, a number of relevant policies have been saved within each of the District areas, guiding development management decisions until such time as the LDF is adopted. These are summarised briefly below.

ENV15 – Development Affecting Flood Risk TR3 - Camping and Caravanning Sites Teesdale GD1 - General Development Criteria ENV17 - Sewerage Infrastructure and Sewage Disposal ENV16 - Development Affecting Rivers Or Streams And Their Corridors

Wear Valley GD1 - General Development Criteria

Chester-le-Street No relevant saved policies

GDP1 - Principles Derwentside HO13 - Accommodation For Travellers

T4 - Assessing The Route and Design of New Road Proposals V8 - Camping, Caravan and Chalets Durham City U9 - Watercourses U10 - Flood Plains

Sedgefield No relevant saved policies

Easington No relevant saved policies

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APPENDIX D Previous Investigations

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LOCAL AUTHORITY INVESTIGATIONS

Derwentside District Strategic Flood Risk Assessment (2008)

A Level 1 SFRA was prepared for the district of Derwentside, on behalf of Derwentside District Council (abolished April 2009). The study was undertaken by Entec in accordance with PPS25 and the PPS25 Practice Guide, and was published in December 2008. The SFRA provides an overview of areas at risk of river flooding, in addition to a record of locations within the district that are known to have been affected by historical flooding (from all sources) prior to 2008. A review of potential emerging development sites within the district was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25. Wear Valley District Strategic Flood Risk Assessment (2008)

A Level 1 SFRA was prepared for the district of Wear Valley, on behalf of Wear Valley District Council (abolished April 2009). The study was undertaken by Entec in accordance with PPS25 and the PPS25 Practice Guide, and was published in December 2008. The SFRA provides an overview of areas at risk of river flooding, in addition to a record of locations within the district that are known to have been affected by historical flooding (from all sources) prior to 2008. A review of potential emerging development sites within the district was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25. Chester-le-Street District Strategic Flood Risk Assessment (2008)

A Level 1 SFRA was prepared for the district of Chester-le-Street, on behalf of Chester-le-Street District Council (abolished April 2009). The study was undertaken by Entec in accordance with PPS25 and the PPS25 Practice Guide, and was published in December 2008. The SFRA provides an overview of areas at risk of river flooding, in addition to a record of locations within the district that are known to have been affected by historical flooding (from all sources) prior to 2008. A review of potential emerging development sites within the district was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25.

City of Durham District Strategic Flood Risk Assessment (2008)

A Level 1 SFRA was prepared for the City of Durham, on behalf of City of Durham Council (abolished April 2009). The study was undertaken by Entec in accordance with PPS25 and the PPS25 Practice Guide, and was published in December 2008. The SFRA provides an overview of areas at risk of river flooding, in addition to a record of locations within the city that are known to have been affected by historical flooding (from all sources) prior to 2008.

A review of potential emerging development sites within the city was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25. Durham County Strategic Flood Risk Assessment (2008) – Minerals & Waste

A Level 1 SFRA was prepared for the County of Durham, on behalf of Durham County Council (pre April 2009). The study was undertaken by Entec in accordance with PPS25 and the PPS25 Practice Guide, and was published in December 2008. The SFRA provides an overview of areas at risk of river flooding, in addition to a record of locations within the County that are known to have been affected by historical flooding (from all sources) prior to 2008. A review of potential emerging minerals and waste sites within the County was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25.

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Easington Strategic Flood Risk Assessment (Draft, 2008)

A draft Level 1 SFRA was prepared for the district of Easington, prepared in May 2008 by Easington District Council (abolished April 2009). The study was undertaken in accordance with PPS25, and provides an overview of areas at risk of river flooding. A review of potential emerging development sites within the district was carried out within the SFRA, highlighting areas within which flooding may pose a constraint under PPS25. Sedgefield Strategic Flood Risk Assessment (2005)

A SFRA was prepared for the borough of Sedgefield, on behalf of Sedgefield Borough Council (abolished April 2009). The study was undertaken by JBA Consulting in accordance with PPG25, providing an overview of areas at risk of river flooding. The Sedgefield SFRA was published in September 2005. Multi Agency Flood Plan (2009)

The Multi Agency Flood Plan was published by the County Durham and Darlington Local Resilience Forum in April 2009. The plan has been prepared “to provide a framework of procedures which ensures a coordinated and flexible multi agency response to major flood incidents in the County Durham and Darlington area.” The plan evaluates those areas that are at susceptible flooding from rivers and/or the sea, considering the degree of vulnerability of the community (and hence the appropriate action that should be taken by responders) that will be placed at risk should a flood occur.

ENVIRONMENT AGENCY INVESTIGATIONS Catchment Flood Management Plans (CFMP), 2008 River Wear, River Tyne & River Tees

The River Wear, River Tyne and River Tees CFMPs were published by the Environment Agency in December 2008. The CFMP “will allow us (the Environment Agency) to use a scientific approach to better understand flood risk from all sources now and in the future, describe how the river catchment behaves and identify what the most sustainable flood risk management policies will be over the next 50 to 100 years. We can then use this plan to manage flood risk in the long-term in the most effective way, taking into account potential climate change and other pressures that may be placed upon the natural water system. We will use the plan to steer our future investment, policies and overall flood risk management activities for the catchment.”

The CFMP provides a comprehensive overview of areas within the catchment that are susceptible to flooding from the River Wear, the River Tees, and the River Tyne (and their tributaries), both today, and in the future as a result of climate change. The CFMP evaluates the potential impact that flooding may have upon communities and the natural environment, and sets out the Environment Agency’s adopted investment policy for flood risk management into the future. An overview of the Environment Agency’s recommended policies for the catchment (including the County of Durham) is provided in Figures D1 to D3 below.

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Figure D1 Environment Agency CFMP Policy Recommendations River Tyne Catchment

Figure D2 Environment Agency CFMP Policy Recommendations River Wear Catchment

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Figure D3 Environment Agency CFMP Policy Recommendations River Tees Catchment

National funding for flood defence within England is limited, and considerable effort is placed into prioritising ‘need’ to ensure that valuable resources are directed to those areas of greatest vulnerability. It should also be recognised that the construction of flood defences does not fully remove the risk of flooding, as explained in Section 5.3 of this SFRA. It follows therefore that the Environment Agency cannot manage the risk of flooding alone. Partnering with regional and local authorities, local industries and individual property owners is essential to ensure that a long term reduction in the risk of flooding is achieved. Informed decision making by local authorities (i.e. taking flood risk into account throughout the planning process) is a very important element of managing the risk of flooding for the longer term.

NORTH EAST ASSEMBLY

Regional Flood Risk Appraisal Scoping Study (2009)

The North East Regional Flood Risk Appraisal Scoping Study was prepared by JBA Consulting on behalf of the North East Assembly (abolished March 2009). The primary purpose of the Scoping Study was to evaluate how the issue of flood risk may influence the development of regional planning policy across the region, and how this should be addressed to meet the requirements of PPS25. The study was published in January 2009, prior to the establishment of the Durham County and Northumberland unitary authorities (April 2009), and the abolishment of the North East Assembly (March 2009)

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APPENDIX E Data Received to Inform Durham County SFRA

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APPENDIX F Flood Risk Vulnerability Classification (Land Use)

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APPENDIX G Methodology for Delineating Zone 3b Functional Floodplain

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In the absence of detailed hydraulic modelling within the catchments of County Durham, a simple risk-based assessment was carried out (adopting first principles) to delineate Zone 3b Functional Floodplain for planning purposes. The adopted methodology is set out below:

1. The predicted 1 in 100 year flood outline (defined by the Environment Agency flood zone map) is overlain onto the County topography at pre-defined intervals, and a cross section extracted through the river to define the ‘shape’ of the floodplain;

2. Using Manning’s Equation at each identified cross section, an approximation of the 1 in 100 year flow is derived, as a function of the flood level (and extent) defined by the EA Flood Zone Map;

3. For comparison purposes, an estimate of the 1 in 20 year and 1 in 100 year peak design flows is derived at the cross section using the Flood Estimation Handbook (FEH). The ratio between the 20 and 100 year peak design flows is determined;

4. Applying this design flow ratio at each cross section location to the flow determined in (2) above, Manning’s Equation is then used once again to assess the approximate 1 in 20 year flood level (and extent) within the floodplain.

It is highlighted that this methodology assumes that the rivers in County Durham are flowing freely and are not subject to backwater affects. This is considered a reasonable assumption. The simplistic nature of the SFRA modelling is entirely appropriate for planning purposes, but it is important to recognise that a margin of uncertainty in the adopted outlines is inevitable. It must be ensured that the SFRA is used to trigger a more detailed assessment of flood levels at the planning application (i.e. detailed FRA) stage.

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APPENDIX H The 'Simple' Method (FD2320) - Flood Defence Failure

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APPENDIX I Sustainable Drainage Systems (SUDS) - A Guide for Developers

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APPENDIX J Impact of Climate Change (Zone 3a High Probability)

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APPENDIX K Consultation with Town & Parish Councils

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Consultation Letter & Sample Map Circulated to Town & Parish Authorities (August 2009)

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APPENDIX L Flood Risk throughout County Durham

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APPENDIX M Surface Water Flood Risks

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Methodology (Assessment of Surface Water Flood Risk)

The potential risk of surface water flooding has been assessed throughout the County of Durham for strategic planning purposes. The approach taken in the analysis of surface water risks is outlined below.

1. The Digital Terrain Model15 (DTM) was interrogated to identify natural depressions in the local topography within which water may pond;

2. The topography was interrogated to identify natural watershed boundaries, upon which local sub- catchment areas have been delineated. These sub-catchment areas will drain towards the natural depressions identified in (1) above;

3. The rate and volume of runoff that will flow towards each depression was assessed in the following manner:

The county was sub-divided into six ‘like’ geographical zones, based broadly upon the topography, geology, and land use of the area. The adopted areas are presented in the figure below.

For county-wide assessment purposes, it has been assumed that the rainfall and runoff characteristics of the sub-catchments within each area are the same. The adopted rainfall and runoff characteristics for each geographical zone is summarised in the table below.

15 Provided by Durham County Council in July 2009 (refer Section 4.3 of Level 1 SFRA report)

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Rainfall Intensity (mm/hr) Runoff Time of Zone Coefficient Concentration 10 20 50 75 100 (C)

Wear West 30 30.92 38.12 49.98 56.30 61.24 0.40

Wear Central 45 22.73 28.00 36.65 41.25 44.85 0.45

Wear East 60 18.62 22.73 29.42 32.95 35.70 0.50

Tees West 30 30.94 38.14 49.96 56.24 61.16 0.40

Tees Central 45 23.64 29.17 38.29 43.15 46.95 0.45

East 60 19.51 23.94 31.19 35.03 38.03 0.45

The rate of runoff from each sub-catchment area was calculated on this basis using the Rational Method Q = CiA, for the 10, 20, 50, 75 and 100 year design events respectively. The volume of runoff was then determined for each sub-catchment area assuming a simple unit hydrograph, as depicted below.

4. An approximation of the underground drainage capacity was taken, in discussion with Council Technical Services. In areas of Durham, Chester-le-Street and Consett, recent investment by Northumbrian Water has provided an indicative standard of protection of 1 in 40 years. In Peterlee and Murton, the indicative standard of protection is estimated to be no greater than 1 in 5 years. Throughout the remainder of the county, the capacity of the drainage system has been assumed to be 1 in 10 years. This flow was deducted from the contributing runoff (calculated in (3) above) draining to each depression.

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5. The depth of flow was determined within each depression, for each return period. This was calculated simply as the volume of flow (calculated in (4) above) divided by the surface area16 of the depression.

6. The threshold of surface water flooding was determined for each depression, assessed (for SFRA purposes) as the return period in which the anticipated depth of flooding exceeds 100mm.

7. The change in surface gradient was interrogated to identify potential flow routes along which runoff may concentrate. These have been delineated as overland flow paths;

8. A number of historical incidents of surface water related flooding have been identified countywide. These were compared with the predicted ‘at risk’ areas, in liaison with the Council Technical Services team, to provide a sensibility check for the surface water risk assessment, indicating a strong correlation in most areas.

Comparison with Environment Agency National Mapping (Areas Susceptible to Surface Water Flooding)

A comparison with the Environment Agency’s national Areas Susceptible to Surface Water mapping (2009) was carried out. There is a strong correlation in the mapping of overland flow routes, however some discrepancies were evident in the delineation of areas susceptible to local ponding. Differences in the methodology adopted by this SFRA and the EA national mapping are considered the primary cause of these discrepancies, and these are briefly explained below:

1. The basic assumption in the national mapping is that there is a ‘constant’ capacity in the local drainage system. This is too simplistic in Durham, and a half day workshop was held with the Council engineers to assess where this should be modified. The hydrology used in SFRA surface water assessment reflects a variable (and more realistic) approximation of drainage capacity.

2. The national mapping has heavily filtered local depressions, and is therefore representing largely only overland flow & river routes within Durham (given the nature of the local topography). This is an over-simplification which has resulted in known problem areas in the County being excluded. This broad assumption was not taken in the SFRA, and the depressions are therefore more accurately reflected in the SFRA mapping.

3. The SFRA mapping has been interrogated in detail by the Council engineers, and in light of observed surface water flooding incidents in the area. This ‘ground truthing’ has enabled the SFRA to review areas that appear questionable when correlated with local knowledge, and adjust (where necessary) the hydrological assumptions accordingly.

4. The SFRA interrogation has provided much greater detail in the hydrological information available, allowing the mapping of areas at risk of surface water flooding in terms of both threshold (return period), and depth. This information is not available in the national mapping.

Prioritisation of Risk

To inform the future Council decision making with respect to surface water management, a prioritisation of surface water flood risks has been carried out for the County. The following appraisal criteria have been applied for this purpose:

16 For SFRA purposes, it has been necessary to assume that the depressions have ‘straight’ sides, i.e. the surface area is constant for all flow depths. Given the relatively shallow nature of the depressions within the county of Durham, this is not considered to be an unreasonable assumption.

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1. Susceptibility to Surface Water Flooding

Depth of Flooding (1% (1 in 100) Event) Susceptibility <0.1m 0.1m to 0.5m >0.5m

Less than, or equal Medium Medium High to, 5% (1 in 20)

Threshold of 2% ( 1 in 50) to 1% Low Medium High Flooding (1 in 100)

Greater than 1% (1 Low Medium Medium in 100)

2. Prioritised Risk of Surface Water Flooding

Land Use Prioritised Risk Urban Road Non Urban

Low Moderate Minor Minor Susceptibility to Surface Water Medium Significant Moderate Minor Flooding High Significant Moderate Moderate

It is recommended that this prioritisation of surface water risks is used to inform the development of a Surface Water Management Plan (SWMP), enabling effort to be directed towards areas of greatest ‘need’ within the County. The SWMP should seek to evaluate more fully the source and scale of the problem within areas of particular risk, and in liaison with the Council (and Northumbrian Water), identify potential strategies for alleviating this risk. Presentation & Interpretation of Results

Surface Water Risk mapping has been prepared to summarise the findings of the surface water modelling carried out as part of this SFRA. Summary maps (refer Figure M1 to M21) are attached for reference purposes. The following GIS layers have also provided to the Council as an outcome of this SFRA: Z Overland Flow Paths – providing an indication of areas in which runoff is expected to concentrate following heavy rain, flowing overland as sheet flow

Z Flood Depth (Depressions) – providing an indication of the anticipated depth of ponding within localised ‘low points’ in the topography during the 1% (1 in 100) design storm event

Z Threshold of Flooding (Depressions) – providing an indication of the anticipated threshold of surface water flooding within localised ‘low points’. A threshold of flooding of 2% (1 in 50) indicates that surface water flooding is expected to occur in a 2% (1 in 50) storm, calculated assuming that the drainage capacity is as set out in point (4) of the ‘Methodology’ description above

Z Risk of Surface Water Flooding (Depressions) – providing an indication of the relative ‘risk’ that surface water flooding may cause to the local area (refer ‘Prioritisation of Risk’ above)

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It is recommended that the Council and developers reference this information when considering a site for future development. Careful consideration should be taken of overland flow routes and/or localised depressions within, or in close proximity to17, a site. Wherever possible, these should be avoided, particularly where frequent and/or severe (i.e. to depth) surface water flooding is anticipated. As a minimum, the design of the site drainage system should ensure that surface water is managed effectively and safely, in accordance with the design criteria set out in Table 1 of this document.

17 Even though a site itself may not be susceptible to surface water flooding, development may exacerbate existing surface water flooding problems elsewhere. It is important that this is considered as part of the design process.

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APPENDIX N Recommended Triggers for SFRA Review

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Question 1

Has any flooding occurred since the most recent review of the SFRA? If so, the following information should be captured as an addendum to the SFRA:

Z What was the extent of the flooding?

Z On what date did the flooding occur?

Z What was the perceived cause of the flooding?

Z What was the indicative return period of the observed flooding event? (i.e. how often, on average, would an event of that magnitude be observed within the region?)

Z If the flooding was caused by river flooding, are the observed flood extents situated outside of the current Zone 3a? If it is estimated that the return period of the flood is less than the 1% (1 in 100) event, then the flooded areas should be incorporated into Zone 3a to inform future planning decision making.

Question 2

Have there been any amendments to PPS25 or the PPS25 Practice Guide since the previous review of the SFRA? If so, the following key questions should be tested:

Z Do the revisions alter the definition of the PPS25 Flood Zones presented within the SFRA?

Z Do the revisions alter the decision making process required to satisfy the Sequential Test?

Z Do the revisions alter the application of the Exception Test?

Z Do the revisions alter the categorisation of land use vulnerability, presented within Table D2 of PPS25 (December 2006)?

If the answer to any of these core questions is ‘yes’ then a review of the SFRA findings and recommendations should be carried out.

Question 3

Has the Environment Agency issued any amendments to their flood risk mapping and/or standing guidance since the previous policy review? If so:

Z Has any further detailed flood risk mapping been completed within the County, resulting in a change to the predicted 5% (1 in 20), 1% (1 in 100) or 0.1% (1 in 1000) flood extents? If yes, then the PPS25 flood zones should be updated accordingly.

Z Has the assessment of the impacts that climate change may have upon rainfall and/or river flows over time altered? If yes, then a review of the impacts that climate change may have upon the extent of flooding within the County is required.

February 2010 Report No. P9514100112-A02 Durham County SFRA (Level 1)

Z Do the recommendations provided in the SFRA in any way contradict emerging Environment Agency advice with respect to (for example) the provision of emergency access, the setting of floor levels and/or the integration of sustainable drainage techniques? If yes, then a discussion with the Environment Agency is required to ensure an agreed suite of development management requirements are in place.

It is highlighted that the Environment Agency review the Flood Zone Map on a quarterly basis. If this has been revised within the County, the updated Flood Zones will be automatically forwarded to the Council for their reference. It is recommended that only those areas that have been amended by the Environment Agency since the previous SFRA review are reflected in Zone 3 and Zone 2 of the SFRA flood maps. This ensures that the more rigorous analyses carried out as part of the SFRA process are not inadvertently lost by a simple global replacement of the SFRA flood maps with the Flood Zone Maps.

Question 4

Has the implementation of the SFRA raised any particular issues or concerns (by the Council or developers) that need to be reviewed as part of the SFRA process?

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<:=D%(%-7CHI:: Appendix L Flood Risk in County Durham

Contents

CONTENTS ...... I 1.0 MAP A1 (HAMSTERLEY, EBCHESTER, BURNOPFIELD, TANFIELD LEA) ...... 1 1.1 Historical Flooding ...... 1 1.2 Fluvial & Tidal Flood Risk ...... 1 1.3 Surface Water Flood Risk ...... 1 1.4 SUDS Suitability (Topography & Geology) ...... 1 2.0 MAP A2 (URPETH, PELTON, OUSTON)...... 2 2.1 Historical Flooding ...... 2 2.2 Fluvial & Tidal Flood Risk ...... 2 2.3 Surface Water Flood Risk ...... 2 2.4 SUDS Suitability (Topography & Geology) ...... 2 3.0 MAP B1 (COWSHILL) ...... 3 3.1 Historical Flooding ...... 3 3.2 Fluvial & Tidal Flood Risk ...... 3 3.3 Surface Water Flood Risk ...... 3 3.4 SUDS Suitability (Topography & Geology) ...... 3 4.0 MAP B2 (EDMONDBYERS, HUNSTANWORTH, ROOKHOPE, LINTZGARTH) ...... 4 4.1 Historical Flooding ...... 4 4.2 Fluvial & Tidal Flood Risk ...... 4 4.3 Surface Water Flood Risk ...... 4 4.4 SUDS Suitability (Topography & Geology) ...... 4 5.0 MAP B3 (CONSETT, LANCHESTER, ANNFIELD PLAIN) ...... 5 5.1 Historical Flooding ...... 5 5.2 Fluvial & Tidal Flood Risk ...... 5 5.3 Surface Water Flood Risk ...... 5 5.4 SUDS Suitability (Topography & Geology) ...... 5 6.0 MAP B4 ...... 6 6.1 Map B4 (Stanley) ...... 6 6.1.1 Historical Flooding ...... 6 6.1.2 Fluvial & Tidal Flood Risk ...... 6 6.1.3 Surface Water Flood Risk ...... 6 6.2 Map B4 (Chester-le-Street) ...... 6 6.2.1 Historical Flooding ...... 6 6.2.2 Fluvial & Tidal Flood Risk ...... 7 6.2.3 Surface Water Flood Risk ...... 7 6.3 Map B4 (Durham) ...... 7 6.3.1 Historical Flooding ...... 7 6.3.2 Fluvial & Tidal Flood Risk ...... 7

i Appendix L Flood Risk in County Durham 6.3.3 Surface Water Flood Risk ...... 8 6.4 Map B4 (Langley Park, Witton Gilbert, Sacriston, Esh Winning, Bournmoor) ...... 8 6.4.1 Historical Flooding ...... 8 6.4.2 Fluvial & Tidal Flood Risk ...... 8 6.4.3 Surface Water Flood Risk ...... 8 6.5 SUDS Suitability (Topography & Geology) ...... 8 7.0 MAP B5 ...... 10 7.1 Map B5 (Seaham) ...... 10 7.1.1 Historical Flooding ...... 10 7.1.2 Fluvial & Tidal Flood Risk ...... 10 7.1.3 Surface Water Flood Risk ...... 10 7.2 Map B5 (Easington Colliery, Pittington, Murton, Haswell, South Hetton, Ludworth) ...... 10 7.2.1 Historical Flooding ...... 10 7.2.2 Fluvial & Tidal Flood Risk ...... 11 7.2.3 Surface Water Flood Risk ...... 11 7.3 SUDS Suitability (Topography & Geology) ...... 11 8.0 MAP C1 (IRESHOPE MOOR) ...... 12 8.1 Historical Flooding ...... 12 8.2 Fluvial & Tidal Flood Risk ...... 12 8.3 Surface Water Flood Risk ...... 12 8.4 SUDS Suitability (Topography & Geology) ...... 12 9.0 MAP C2 ...... 13 9.1 Map C2 (Westerhope Moor) ...... 13 9.1.1 Historical Flooding ...... 13 9.1.2 Fluvial & Tidal Flood Risk ...... 13 9.1.3 Surface Water Flood Risk ...... 13 9.2 Map C2 (Stanhope) ...... 13 9.2.1 Historical Flooding ...... 13 9.2.2 Fluvial & Tidal Flood Risk ...... 13 9.2.3 Surface Water Flood Risk ...... 14 9.3 SUDS Suitability (Topography & Geology) ...... 14 10.0 MAP C3 ...... 15 10.1 Map C3 (Wolsingham & Tow Law) ...... 15 10.1.1 Historical Flooding ...... 15 10.1.2 Fluvial & Tidal Flood Risk ...... 15 10.1.3 Surface Water Flood Risk ...... 15 10.2 Map C3 (Hamsterley & Witton-le-Wear) ...... 15 10.2.1 Historical Flooding ...... 15 10.2.2 Fluvial & Tidal Flood Risk ...... 15 10.2.3 Surface Water Flood Risk ...... 15 10.3 SUDS Suitability (Topography & Geology) ...... 16 11.0 MAP C4 ...... 17 11.1 Map C4 (Crook & Howden-le-Wear) ...... 17

ii Appendix L Flood Risk in County Durham 11.1.1 Historical Flooding ...... 17 11.1.2 Fluvial & Tidal Flood Risk ...... 17 11.1.3 Surface Water Flood Risk ...... 17 11.2 Map C4 (Willington) ...... 17 11.2.1 Historical Flooding ...... 17 11.2.2 Fluvial & Tidal Flood Risk ...... 17 11.2.3 Surface Water Flood Risk ...... 18 11.3 Map C4 (Witton Park) ...... 18 11.3.1 Historical Flooding ...... 18 11.3.2 Fluvial & Tidal Flood Risk ...... 18 11.3.3 Surface Water Flood Risk ...... 18 11.4 Map C4 (Spennymoor) ...... 19 11.4.1 Historical Flooding ...... 19 11.4.2 Fluvial & Tidal Flood Risk ...... 19 11.4.3 Surface Water Flood Risk ...... 19 11.5 Mapc C4 (Brandon) ...... 19 11.5.1 Historical Flooding ...... 19 11.5.2 Fluvial & Tidal Flood Risk ...... 19 11.6 Surface Water Flood Risk ...... 19 11.7 SUDS Suitability (Topography & Geology) ...... 20 12.0 MAP C5 ...... 21 12.1 Map C5 (Peterlee) ...... 21 12.1.1 Historical Flooding ...... 21 12.1.2 Fluvial & Tidal Flood Risk ...... 21 12.1.3 Surface Water Flood Risk ...... 21 12.2 Map C5 (Coxhoe, Trimdon, Trimdon Colliery, Bowburn, Wingate) ...... 21 12.2.1 Historical Flooding ...... 21 12.2.2 Fluvial & Tidal Flood Risk ...... 21 12.2.3 Surface Water Flood Risk ...... 22 12.3 SUDS Suitability (Topography & Geology) ...... 22 13.0 MAP C6 (EAST COAST) ...... 23 13.1 Historical Flooding ...... 23 13.2 Fluvial & Tidal Flood Risk ...... 23 13.3 Surface Water Flood Risk ...... 23 13.4 SUDS Suitability (Topography & Geology) ...... 23 14.0 MAP D1 (GRAINS O’ TH’ BECK) ...... 24 14.1 Historical Flooding ...... 24 14.2 Fluvial & Tidal Flood Risk ...... 24 14.3 Surface Water Flood Risk ...... 24 14.4 SUDS Suitability (Topography & Geology) ...... 24 15.0 MAP D2 (MICKLETON & MIDDLETON-IN-TEESDALE) ...... 25 15.1 Historical Flooding ...... 25 15.2 Fluvial & Tidal Flood Risk ...... 25 15.3 Surface Water Flood Risk ...... 25 15.4 SUDS Suitability (Topography & Geology) ...... 25

iii Appendix L Flood Risk in County Durham 16.0 MAP D3 (STAINTON & STAINDROP) ...... 26 16.1 Historical Flooding ...... 26 16.2 Fluvial & Tidal Flood Risk ...... 26 16.3 Surface Water Flood Risk ...... 26 16.4 SUDS Suitability (Topography & Geology) ...... 26 17.0 MAP D4 ...... 27 17.1 Map D4 (Bishop Auckland) ...... 27 17.1.1 Historical Flooding ...... 27 17.1.2 Fluvial & Tidal Flood Risk ...... 27 17.1.3 Surface Water Flood Risk ...... 27 17.2 Map D4 (Newton Aycliffe) ...... 28 17.2.1 Historical Flooding ...... 28 17.2.2 Fluvial & Tidal Flood Risk ...... 28 17.2.3 Surface Water Flood Risk ...... 28 17.3 Map D4 (Shildon) ...... 28 17.3.1 Historical Flooding ...... 28 17.3.2 Fluvial & Tidal Flood Risk ...... 28 17.3.3 Surface Water Flood Risk ...... 29 17.4 SUDS Suitability (Topography & Geology) ...... 29 18.0 MAP D5 (SEDGEFIELD, BRADBURY AND MORDON) ...... 30 18.1 Historical Flooding ...... 30 18.2 Fluvial & Tidal Flood Risk ...... 30 18.3 Surface Water Flood Risk ...... 30 18.4 SUDS Suitability (Topography & Geology) ...... 30 19.0 MAP E1 (BOWES & GILMONBY) ...... 31 19.1 Historical Flooding ...... 31 19.2 Fluvial & Tidal Flood Risk ...... 31 19.3 Surface Water Flood Risk ...... 31 19.4 SUDS Suitability (Topography & Geology) ...... 31 20.0 MAP E2 ...... 32 20.1 Map E2 (Barnard Castle) ...... 32 20.1.1 Historical Flooding ...... 32 20.1.2 Fluvial & Tidal Flood Risk ...... 32 20.1.3 Surface Water Flood Risk ...... 32 20.2 Map E2 (Ovington) ...... 32 20.2.1 Historical Flooding ...... 32 20.2.2 Fluvial & Tidal Flood Risk ...... 32 20.2.3 Surface Water Flood Risk ...... 33 20.3 SUDS Suitability (Topography & Geology) ...... 33 21.0 MAP E3 (GAINFORD AND WINSTON) ...... 34 21.1 Historical Flooding ...... 34 21.2 Fluvial & Tidal Flood Risk ...... 34 21.3 Surface Water Flood Risk ...... 34 21.4 SUDS Suitability (Topography & Geology) ...... 34

iv Appendix L Flood Risk in County Durham

1.0 MAP A1 (HAMSTERLEY, EBCHESTER, BURNOPFIELD, TANFIELD LEA)

1.1 Historical Flooding

There are 4 recorded incidents of historical flooding, one at Shotley Bridge, two in Burnopfield and one at East Tanfield Station. Flooding at East Tanfield Station was a result of surcharging at the intersection. No further details for this or the other three events are available.

1.2 Fluvial & Tidal Flood Risk

Flood Zones 2 and 3 of the River Derwent runs along the county boundary from Shotley Bridge in the south east, along the western and northern finges of Ebchester and Hamsterley respectively, before flowing away from the county boundary approximately 1 km north of Burnopfield. Pont Burn poses a risk to residential properties and the B6310 between Hamsterley Hall and the confluence with the River Derwent. The floodplain of Kyo Burn situated east of Harperley poses a risk to a few residential properties and a Public House along Harperley Lane. Kyo Burn flows north east from Harperley towards Tanfield Lea and presents a flood risk to properties along Bradbury Close, the School on Good Street and residential and commercial properties opposite the school. Flood Zone 3 of Ryo Burn extends to East Tanfield Station.

1.3 Surface Water Flood Risk

Areas susceptible to surface water flooding are typically at risk from rainfall events with less than a 1 % AEP, however localised flooding in Burnopfield, Medomsley and Hamsterley Mill may occur during less intense storms with a 5 % AEP. Although flood depths will vary depending on the local topography, typical flood depths during a 1 % AEP event do not exceed 0.25 m. The aforementioned areas that are more susceptible to flooding are likely to experience greater flood depth.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points. Overland flow paths run through Burnopfield, Medomsley, Hamsterley and Tanfield Lea.

1.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology and coal measures of variable permeability, overlain by a till soil layer within the sides of the river valley (see Figure 6). The topography falls relatively steeply towards the north (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils have a relatively high clay content, and therefore are low permeability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

1 Appendix L Flood Risk in County Durham

2.0 MAP A2 (URPETH, PELTON, OUSTON)

2.1 Historical Flooding

Surface water runoff from farmland in West Pelton is considered to be responsible for property flooding. Consultation with Durham County Council highlighted properties in New Field Road, Pelton experienced flooding when the railway formed a dam. The northbound exit at junction 63 of the A1(M) is known to suffer from surface water flooding following heavy rain.

2.2 Fluvial & Tidal Flood Risk

The River Team poses a flood risk to Beamish Hall and a few properties located along the county boundary from High Forge to Ouston. Flooding from the River Wear poses a risk to the A1(M) at junction 63, where the road is situated in Flood Zone 2. East of junction 63 the River Wear poses a risk to a residential property located on Black Drive, which appears to be on the edge of Flood Zone 3, and agricultural land and woodland.

2.3 Surface Water Flood Risk

Areas susceptible to Surface Water flooding are typically at risk from rainfall events with less than a 1 % AEP, however localised flooding in Pelton, Ouston and Urpeth may occur during less intense storms with a 5 % AEP. Although flood depths will vary depending on the local topography, typical flood depths during a 1 % AEP event do not exceed 0.25 m. The aforementioned areas that are more susceptible to flooding are likely to experience greater flood depth. Ouston and Urpeth in particular are susceptible to surface water flooding in excess of 0.5 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points. Overland flow paths run through Urpeth and Pelton.

2.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a till soil layer (see Figure 6). The topography falls relatively steeply from west to east, with relatively flat ground levels evident along the River Wear corridor (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils on the higher ground are low permeability drift deposits. Within the lower lying areas, the soils are typically deep and coarse textured, with a relatively high permeability. For this reason, infiltration devices and permeable surfaces should function efficiently within the lower lying eastern areas of this map window, however care will need to be taken during the design process to ensure that the adopted SUDS techniques are suitable within the local topography (i.e. taking account of any local steep slopes). Infiltration techniques are likely to be less effective within the more elevated areas to the west of the Wear (Stanley). Basins, ponds and tanked systems are more suitable in this area, and once again careful consideration should be taken of the steep topography.

2 Appendix L Flood Risk in County Durham

3.0 MAP B1 (COWSHILL)

3.1 Historical Flooding

Two properties in Burtree Ford, Cowshill have been affected by surface water flooding following construction of dams by a private landowner that backed up water in the local drainage system. Since the event DCC have improved the outlet and implemented an overflow system.

3.2 Fluvial & Tidal Flood Risk

The Flood Zone extents within Map B1, which features Killhope Burn, Wellhope Burn, Sedling Burn, Middlehope Burn and Rookhope Burn, are relatively small. The confluence between Killhope Burn and Middlehope, which forms the River Wear, is approximately 1.5 km west of Cowshill and flows through Cowshill. Sedling Burn flows south to the River Wear through the eastern extent of Cowshill. Both the River Wear and Sedling Burn pose a flood risk to a number properties within Cowshill, with a large extent of the village located in Flood Zone 3.

3.3 Surface Water Flood Risk

The extent of surface water flooding is minimal and these areas are typically at risk from rainfall events with less than a 1 % AEP, however localised flooding in Cowshill may occur during less intense storms with a 5 % AEP. Although flood depths will vary depending on the local topography, typical flood depths during a 1 % AEP event do not exceed 0.25 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points. Overland flow paths have been identified in Cowshill, which are sourced by the surrounding high ground.

3.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground (see Figure 6). The elevated topography is relatively consistent across the map area (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils have a relatively high organic content. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable however an impermeable lining will be required. Tanked systems will function effectively in this area. In both instances, careful consideration will need to be taken of buoyancy (of the structure) and the changes in surrounding groundwater levels during saturated conditions.

3 Appendix L Flood Risk in County Durham

4.0 MAP B2 (EDMONDBYERS, HUNSTANWORTH, ROOKHOPE, LINTZGARTH)

4.1 Historical Flooding

Burnside Cottages, Lintzgarth have experienced flooding as a result of Rookhope Burn backing up at the nearby bridge.

4.2 Fluvial & Tidal Flood Risk

The northern extent of Burnside Cottages is understood to have experienced flooding in the past and Flood Zone mapping illustrates they are partially located within the Flood Zone of Rookhope Burn. Rookhope Burn flows along the south-western extent of the village where it is fed by Bolt’s Burn. The confluence between the two Burns is located immediately south of the Public House within Rookhope and poses a risk to residential properties in addition to the Public House. The Flood Zone extents at Waskerley Reservoir are unlikely to be correct due to the presence of the dam; however the reservoir poses a major residual risk to the properties immediately downstream. Derwent reservoir also presents a residual risk to properties downstream. Bolt’s Burn, which runs northwards from Ramshaw towards Blanchland, poses a risk to a few properties in Ramshaw. In addition some properties around Derwent Bridge and Eddy’s Bridhe are located within Flood Zone 3 of the River Derwent.

4.3 Surface Water Flood Risk

The extent of surface water flooding is minimal and these areas are typically at risk from rainfall events with less than a 1 % AEP, however localised flooding in Edmondbyers, Hunstanworth, Rookhope and Lintzgarth may occur during less intense storms with a 5 % AEP. Typical flood depths during a 1 % AEP event do not exceed 0.25 m but will vary with the local topography.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

4.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground (see Figure 6). The elevated topography is relatively consistent across the map area (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils have a relatively high organic content. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable however an impermeable lining will be required. Tanked systems will function effectively in this area. In both instances, careful consideration will need to be taken of buoyancy (of the structure) and the changes in surrounding groundwater levels during saturated conditions.

4 Appendix L Flood Risk in County Durham

5.0 MAP B3 (CONSETT, LANCHESTER, ANNFIELD PLAIN)

5.1 Historical Flooding

A number of historical flood incidents have been recorded in areas on Map B3, including Castleside, Consett and Lanchester. Many of these recorded incidents have very limited details. Surface water runoff and inadequate drainage regularly causes problems each year to properties located in Delves, south east of Consett. Lanchester has at least 12 recorded incidents of flooding, largely attributed to drainage problems. Local drainage has since been inspected and works carried out to increase capacity and regular maintenance has reduced the risk of flooding. A couple of incidents of surface water flooding at the south-western extent of Lanchester have been raised by Lanchester Parish Council. Greencroft Parish Council has also reported five incidents of flooding related to surface water runoff.

5.2 Fluvial & Tidal Flood Risk

A few properties in central Allensford are situated within Flood Zone 3 of the River Derwent. From Allensford the river flows northwards to the western boundary of Consett, near Bridgehill and Benfieldside. Much of the floodplain is located on the western bank of the river; however some properties in close proximity to the river are located within Flood Zone 3. A number of Burns including Stockerley Burn, Howden Burn and Backgill Burn merge at the northern extent of Lanchester and flows through the centre Lanchester, where Alderene Burn discharges into the Burn from the west. At the southern extent of Lanchester the Burn discharges into the River Browney by Greenwell Ford. Properties within approximately 100 m of the Burn running through central Lanchester are predominantly located within Flood Zone 2 and therefore at risk of flooding.

5.3 Surface Water Flood Risk

Areas susceptible to surface water flooding are typically at risk from rainfall events with less than a 1 % AEP. A number of areas towards the eastern extent of Consett are at risk of surface water flooding following a 2 % AEP rainfall event. Leadgate, Annfield Plain and Lanchester are also at risk of flooding, particularly during less intense storms with a 5 % AEP. Typical flood depths in Map B3 do not exceed 0.25 m, however the aforementioned areas may experience flood depths greater than 1 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

5.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying coal measures of variable permeability, overlain by a till soil layer within the sides of the river valley (see Figure 6). The topography falls relatively steeply from west to east (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils on the higher ground are low permeability drift deposits. Within the lower lying areas, the soils appear to have a relatively high clay content, and therefore once again are low permeability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

5 Appendix L Flood Risk in County Durham

6.0 MAP B4

6.1 Map B4 (Stanley)

6.1.1 Historical Flooding

Surface water runoff and inadequate drainage Shield Row and Kip Hill (See also Map A2) are known to have caused flooding to residential properties. Further incidents related to surface water drainage have occurred in central and South Stanley. Additional incidents south of Stanley Burn have also been reported.

6.1.2 Fluvial & Tidal Flood Risk

Stanley Burn and Twizell Burn flow along the southern perimeter of South Moor and South Stanley, from west to east, and pose a flood risk to nearby properties.

Information regarding minor watercourses flowing through Stanley, which are listed below, have been provided from previous SFRAs:

Unnamed watercourse flows north along the western extent of Stanley to Houghwell Burn and River Team; Unnamed watercourse in Kiphill flows north to Houghwell Burn and River Team; Unnamed watercourse flows through South Moor; and Unnamed watercourse flows through Low Stanley.

The risk of flooding from these watercourses is unknown.

6.1.3 Surface Water Flood Risk

Areas of Stanley susceptible to surface water flooding are typically at risk from rainfall events with a 5 % or less AEP. Flood depths during a 1 % AEP event may exceed 1 m in some areas of East and South Stanley.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

6.2 Map B4 (Chester-le-Street)

6.2.1 Historical Flooding

A number of flood incidents throughout Chester-le-Street have been attributed to fluvial flooding from the River Wear and Chester Burn, plus surface water flooding and drainage issues. The most recent flood event occurred in July 2009 which affected a Tesco store north of Chester Burn and a park near Lumley Castle.

6 Appendix L Flood Risk in County Durham

6.2.2 Fluvial & Tidal Flood Risk

The Chester Burn flows west to east from Pelton Fell and discharges into the River Wear by the Sewage Works. The River Wear flows along the eastern extent of Chester-le-Street from south to north. Each poses a flood risk to nearby properties and are known to have caused problems in the past. South Burn flows by Chester Moor, however the extent of Flood Zones 2 and 3 are very limited; likely a result of a small catchment area. Stretches of Chester Burn are protected by flood defences of varying design standards. The cricket ground and nearby properties also benefit from flood defences.

6.2.3 Surface Water Flood Risk

Areas of central Chester-le-Street susceptible to surface water flooding are typically at risk from rainfall events with a 2 % or less AEP. Towards the northern extent of Chester-le-Street, north east of South Pelaw, surface water flooding may occur during a 5 % AEP event. Flood depths during a 1 % AEP event are typically less than 0.25 m but may be as deep as 0.5 m and 1 m in central and northern Chester-le-Street respectively.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

6.3 Map B4 (Durham)

6.3.1 Historical Flooding

Numerous historical flood incidents have been recorded throughout Durham, the majority of which are located around the River Wear and to the east. Notable historical flood incidents on the River Wear include March 1968, December 1978, and January 1995. Areas around the confluence between an unnamed minor watercourse and River Wear in central Durham are known to flood several times per year as a result of high river levels which are exacerbated by trees, vegetation and rubbish damming the river. In addition to fluvial flooding, a large number of drainage related flooding has been reported west of the River Wear in Gilesgate, Gilesgate Moor, Belmont and Carrville. Drainage related issues have also been recorded in Framwellgate Moor and Newton Hall.

6.3.2 Fluvial & Tidal Flood Risk

The River Wear flows north towards Durham, meandering west, south and then north towards central Durham, before turning northeast as the river leaves Durham along its northern border. Flood Zone mapping indicates water is largely confined to the River Wear within central areas of Durham, however upstream of Kingsgate Bridge and downstream of A690 Flood Zones 2 and 3 spill out over a larger area.

The University car park on New Elvet benefits from a flood wall, with a design standard of 10% AEP. Further flood defences along the River Wear are located upstream of Durham, providing protection for agricultural and recreational land.

Information regarding minor watercourses flowing through Durham, which are listed below, have been provided from previous SFRAs:

Pelaw Wood Beck flows westwards to the River Wear through the periphery of Durham; Unamed watercourse in flows eastwards through North End before joining the River Wear in central Durham; and Unamed watercourse flows from Framwellgate Moor to the River Wear.

7 Appendix L Flood Risk in County Durham

The risk of flooding from these watercourses is unknown.

6.3.3 Surface Water Flood Risk

Localised surface water flooding poses a risk to areas throughout Durham. West of the River Wear a number of areas are at risk of flooding from surface water flooding during storm events with a 5 % or less AEP. Areas that may be particularly at risk to such events include the area west of Southstreet Banks, North End, County Hall, Newton Hall and Framwellgate Moor. East of the River Wear the likelihood of surface water flooding is not as great. Subsequently, flood depths during a 1 % AEP event are likely to be greater west of the river. Surface water flooding generally won’t exceed 0.25 m, however flooding in the aforementioned areas west of the River Wear may exceed 1 m.

6.4 Map B4 (Langley Park, Witton Gilbert, Sacriston, Esh Winning, Bournmoor)

6.4.1 Historical Flooding

A number of locations throughout the area depicted in Map B4 have experienced drainage related flooding.

6.4.2 Fluvial & Tidal Flood Risk

Z Sacriston, Sherburn, Witton Gilbert, Great Lumley and Bearpark are not considered to be at risk of fluvial flooding.

Z The River Browney flows along the northern boundary of Langley Park and may pose a risk to nearby property

Z Rowley Burn enters Esh Winning from the west before discharging into Hedleyhope Burn just west of the church in central Esh Winning. Hedleyhope Burn flows along the northern perimeter of Esh Winning and discharges into the River Deerness by the sewage treatment works. Fluvial flooding poses a risk to the northern and southern perimeter of Esh Winning. Note Rowley Burn, Hedley Hope Burn and the River Deerness meander outside of the flood extents.

Z A tributary of the River Wear flows east to west, crossing the county border by New Lambton near Bournmoor. The tributary poses a flood risk to some commercial properties along the southern border of Bournmoor.

6.4.3 Surface Water Flood Risk

Areas of Map B4 susceptible to surface water flooding, including Witton Gilbert, Langley Park, Sacriston, Esh Winning and Bournmoor are typically at risk from rainfall events with a 5 % AEP. During a 1 % AEP event flood depths may reach or even exceed 1 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

6.5 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a till soil layer within the sides of the river valley (see Figure 6). The topography falls

8 Appendix L Flood Risk in County Durham relatively steeply from west to east, with relatively flat ground levels evident along the River Wear corridor (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils on the higher ground are low permeability drift deposits. Within the lower lying areas, the soils are typically deep and coarse textured, with a relatively high permeability. For this reason, infiltration devices and permeable surfaces should function efficiently within the lower lying eastern areas of this map window (surrounding Chester-le-Street and Durham), however care will need to be taken during the design process to ensure that the adopted SUDS techniques are suitable within the local topography (i.e. taking account of any local steep slopes). Infiltration techniques are likely to be less effective within the more elevated areas to the west of the major towns. Basins, ponds and tanked systems are more suitable in this area, and once again careful consideration should be taken of the steep topography.

9 Appendix L Flood Risk in County Durham

7.0 MAP B5

7.1 Map B5 (Seaham)

7.1.1 Historical Flooding

Only two incidents of historical flooding are located within Seaham, one regarding drainage capacity and the other a blockage of Dalton Burn.

7.1.2 Fluvial & Tidal Flood Risk

Tidal flooding in Seaham from the North Sea is very limited due to the cliffs and ground level of properties. Dalton Burn and another stream to the north flow through Seaham and discharge into the North Sea. They may pose a risk to property along its reach.

Easington Colliery is not considered to be at risk of tidal flooding.

Murton and Haswell are not considered to be at risk of fluvial flooding.

Information regarding minor watercourses flowing through Stanley, which are listed below, have been provided from previous SFRAs:

Unnamed watercourse flows north along the western extent of Stanley to Houghwell Burn and River Team;. Unamed watercourse in Kiphill flows north to Houghwell Burn and River Team; Unamed watercourse flows through South Moor; and Unnamed watercourse flows through Low Stanley.

The risk of flooding from these watercourses is unknown.

7.1.3 Surface Water Flood Risk

Areas of Seaham susceptible to surface water flooding are typically at risk from rainfall events with a 5 % or less AEP. There is a notable concentration of areas at risk of flooding during a 5 % AEP event by the intersection of the B1285 and B1404, Station Road, and by Seaham Railway Station. During a 1 % AEP event, flood depths are generally less than 0.25 m but may exceed 1 m in some areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

7.2 Map B5 (Easington Colliery, Pittington, Murton, Haswell, South Hetton, Ludworth)

7.2.1 Historical Flooding

An unnamed watercourse by Milton Lane, Easington Colliery has caused flooding to residential property. Pittington has experienced several flooding incicdents related to surface water runoff and Coalford Beck has been responsible for flooding by the sewage works near Pittington. Additional historical incicdents are illustrated in Map B5.

10 Appendix L Flood Risk in County Durham

7.2.2 Fluvial & Tidal Flood Risk

Easington Colliery is not considered to be at risk of tidal flooding.

An unnamed watercourse by Milton Lane, Easington Colliery has caused flooding to residential property highlighting a fluvial flood risk in the area. Two unnamed watercourses flow along the northwestern and southern perimeter of Ludworth and may be a source of flood risk to nearby property. Coldwell Burn flows southwest from South Hetton and may pose a flood risk to residential properties close to its banks.

Pittington, Murton and Haswell are not considered to be at risk of fluvial flooding.

7.2.3 Surface Water Flood Risk

Areas throughout Map B5, including Easington Colliery, Pittngton, Haswell, South Hetton and Ludworthare at risk of surface water flood, these areas are typically at risk from rainfall events with a 5 % AEP. During a 1 % AEP event flood depths may reach 1 m. Murton is at risk of flooding from 10 % AEP events, and flooding during a 1 % AEP rainfall event may be up to 1 m deep

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

7.3 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology that is highly permeable (see Figure 6). The topography falls relatively undulating, falling away to the east and west respectively from an area of higher ground (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils within this area of variable permeability, from low to intermediate. For this reason, infiltration devices and permeable surfaces may function effectively within this area, however local geological conditions will need to be considered as part of the design process to ensure the suitability of the soils within the site. Basins, ponds & tanked systems will all function effectively in this area. The undulating nature of the local topography would seem to indicate that local changes in ground level are unlikely to pose a design constraint. Finally, whilst there is no immediate evidence of high groundwater levels causing groundwater flooding in this area, a local investigation should be carried out as part of the design process to ensure that this risk is not exacerbated if considering infiltration techniques.

11 Appendix L Flood Risk in County Durham

8.0 MAP C1 (IRESHOPE MOOR)

8.1 Historical Flooding

There is little information regarding historical flooding, which is likely due to the sparse population and low level of corresponding flood risk.

8.2 Fluvial & Tidal Flood Risk

Burnhope Reservoir, which is fed by a series of small watercourses, including Burnhope Burn and Langtae Burn, poses a significant residual flood risk to property downstream. The Flood Zone extents in the vicinity of the reservoir are unlikely to be correct due to the presence of the dam. Ireshope Burn flows in a northeasterly direction through Ireshopeburn where it discharges into the River Wear. The Wear flows in a easterly direction, parallel to the A689 towards East Blackdene. Several properties between Wearhead and Blackdene are at risk of flooding from the River Wear and its tributaries. The Flood Zones of Langdon Beck illustrate a few properties in Langdon Beck are at risk of fluvial flooding.

There are a large number of unnamed minor watercourses presented in Map C1 which are the sources for a number of rivers. Many do not pose a risk however the risk of flooding from unnamed minor watercourses flowing through or by a settlement is unknown.

8.3 Surface Water Flood Risk

The extent of surface water flooding in Map C1 is minimal and typically occurs during 1 % AEP or less events. Such risk has been identified in areas of Ireshopeburn that are susceptile to flooding. Flood depths are unlikely to exceed 0.25 m during a 1 % AEP event.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

8.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground and till deposits in the river valleys (see Figure 6). The elevated topography is relatively consistent across the map area, with ground levels falling relatively rapidly towards the River Wear and River Tees to the north and south respectively (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) indicates that soils throughout the more elevated areas of this map window have a relatively high organic content. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. In contrast, soils along the Wear and Tees river corridors are classified as low or ‘negligibly’ permeable.

For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area. Basins and ponds may be suitable, however in the peat soil areas (i.e. on higher ground) an impermeable lining will be required. Tanked systems will function effectively throughout this area. Careful consideration will need to be taken of buoyancy and obstructions to lateral water movement within the peat layer in elevated areas. Finally, the adopted design must take into account the steep topography to ensure effective implementation.

12 Appendix L Flood Risk in County Durham

9.0 MAP C2

9.1 Map C2 (Westerhope Moor)

9.1.1 Historical Flooding

All historical flood incidents are confined to the catchment of the River Wear, notably Stanhope. Flooding has been recorded in Westgate, Brotherlee and Crawleyside

9.1.2 Fluvial & Tidal Flood Risk

The west, south and southeast of Stanhope are at risk of fluvial flooding from the River Wear, Black Burn and Stanhope Burn. A private boundary wall and Environment Agency maintained floodwall provides a 100 year SoP and runs approximately 600 m north of the railway embankment on the north bank of the River Wear. A minor watercourse, referred to as Allerton Burn in the previous SFRA (SFRA, 2008) flows east through the western extent of Stanhope to Stanhope Burn. The risk of flooding from this watercourse is unknown.

9.1.3 Surface Water Flood Risk

Areas susceptible to surface water flooding are largely confined to the catchment of the River Wear. Such areas are typically at risk from rainfall events with a 5 % or less AEP and flood depth during a 1 % AEP is typically less than 0.5 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

9.2 Map C2 (Stanhope)

9.2.1 Historical Flooding

Some of the incidents in Stanhope are attributed to fluvial flooding, despite being located outside the Flood Zones. This indicates the Flood Zone extents in Stanhope may be larger than those illustrated in Map B2.

9.2.2 Fluvial & Tidal Flood Risk

The only major settlements within Map B2 are situated along the River Wear or its tributaries. Blackdene to Stanhope and onto Bridge End the River Wear poses a flood risk. In addition to the River Wear, Westgate may be susceptible to flooding from Middlehope Burn, which flows southwards and discharges into the River Wear in Westgate. East of Westgate Rookhope Burn flows through Eastgate and into the River Wear. The Rookhope Burn confluence is located in Eastgate and poses a flood risk. The former Eastgate Cement Works and Hag Bridge Caravan Park, which are located along the River Wear to the west and east of Rookhope Burn respectively, benefit from a flood defence bank. The defences are only of a 25 and 50 year SOP and therefore a residual risk remains.

13 Appendix L Flood Risk in County Durham

9.2.3 Surface Water Flood Risk

Much of the town is a low risk area susceptible only to less than 1 % AEP rainfall events, however there are localised areas, notably towards the western extent of Stanhope that are at risk of flooding from a 5 % AEP event. Flood depths are unlikely to exceed 0.25 m during a 1 % AEP event.

9.3 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground, with till deposits along the River Wear corridor to the north (see Figure 6). The elevated topography is relatively consistent across the map area, falling steeply to the River Wear (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) indicates that soils have a relatively high organic content throughout much of the area, with an area of intermediate permeability soils forming the River Wear corridor. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. Infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable however an impermeable lining will be required in peaty areas (i.e. on higher ground). Tanked systems will function effectively in this area. In both instances, careful consideration will need to be taken of buoyancy (of the structure) and the changes in surrounding groundwater levels during saturated conditions. The adopted design must take into account the steep topography to ensure effective implementation.

14 Appendix L Flood Risk in County Durham

10.0 MAP C3

10.1 Map C3 (Wolsingham & Tow Law)

10.1.1 Historical Flooding

A couple of issues regarding blockages and backing up of culverts are recorded in the west and north of Wolsingham. Tow Law does not have any records of historical flooding.

10.1.2 Fluvial & Tidal Flood Risk

The River Wear flows west to east along the southern perimeter of Wolsingham. Waskerley Beck flows south, through the centre of Wolsingham to the River Wear. Trods Beck, the southern extent of which appears to be culverted according to the OS map, flows south through Upper Town and discharges into Waskerley Beck. Each of the aforementioned watercourses pose a risk to northern, southern and central Wolsingham. Tow Law is not currently at risk from fluvial flooding.

10.1.3 Surface Water Flood Risk

Areas of Wolsingham that are susceptible to surface water flooding are typically at risk from rainfall events with a 2 % or less AEP. Flood depths during a 1 % AEP event are typically less than 0.25 m but may exceed 1.0 m around the northern extent of the settlement in Holywood. Tow Law is at risk of localised flooding from storm events with a 2 % or less AEP and flood waters may be as deep as 1 m during a 1 % AEP event.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

10.2 Map C3 (Hamsterley & Witton-le-Wear)

10.2.1 Historical Flooding

Surface water flooding has occurred in Hamsterley and Witton le Wear. 38 residential properties and 11 commercial properties in Frosterley were affected by flooding in 1995. During another flood event 4-5 properties at the eastern extent of Frosterley were affected.

10.2.2 Fluvial & Tidal Flood Risk

The River Wear flows west to east along the southern perimeter of Frosterley and poses a flood risk to eastern parts of Frosterley. Witton le Wear and Hamsterley are not currently at risk from fluvial flooding.

10.2.3 Surface Water Flood Risk

Areas of Witton-le-Wear, Hamsterley and Frosterley that are susceptible to surface water flooding are typically at risk from rainfall events with a 5 % AEP or less. During a 1 % AEP event flood depth is not likely to exceed 0.5 m.

15 Appendix L Flood Risk in County Durham

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

10.3 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology of variable permeability, overlain by a till soil layer within the sides of the river valley (see Figure 6). The topography falls relatively steeply from west to east towards the River Wear (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils on the higher ground are low permeability drift deposits. Within the lower lying areas, the soils appear to have a relatively high clay content, and therefore once again are low permeability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

16 Appendix L Flood Risk in County Durham

11.0 MAP C4

11.1 Map C4 (Crook & Howden-le-Wear)

11.1.1 Historical Flooding

Seven flooding incidents recorded in Crook and nearby Billy Row are all attributed to surface water runoff and drainage issues. Flooding in Howden-le-Wear from Beechburn Beck has occurred twice in ten years but has not affected any properties. Flooding is understood to be caused by a stone bridge that restricts flow.

11.1.2 Fluvial & Tidal Flood Risk

Beechburn Beck flows south from Roddymoor, through the eastern part of Crook and along the eastern extent of Howden-le-Wear. Middle Mown Beck flows east and joins Beechburn Beck at the southern extent of Crook. Howden Beck flows through the western extent of Howden-le-Wear and discharges into Beechburn Beck at the southern extent of Howden-le- Wear. The aforementioned Becks have a narrow floodplain but may still pose a risk to nearby properties.

11.1.3 Surface Water Flood Risk

Areas of central and southern Crook and Howden-le-Wear Areas that are susceptible to surface water flooding are typically at risk from rainfall events with during a 2 % AEP. The northern extent of Crook is susceptible to flooding during a storm event with a less than 2 % AEP. Flood depths during a 1 % AEP will likely range between 0 and 0.25 m but in low lying areas may range between 0.25 m and 0.5 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

11.2 Map C4 (Willington)

11.2.1 Historical Flooding

A number of incidents located outside of Flood Zones are a result of flow exceeding drainage capacity and runoff from nearby fields. Country park and NWL treatment works are affected by fluvial flooding from the River Wear and occurs once or twice every five years. Defences west of the treatment works were breached in 1995.

11.2.2 Fluvial & Tidal Flood Risk

South of Willington the River Wear runs from west to east. The Flood Zones of the River Wear pose little threat to the existing extent of Willington. Willington Burn, which flows south from Milkup Bank and along the western extent of Willington, poses a flood risk in this area. Holy Well Burn and River Wear confluence may pose a flood risk to the southern extent of Willington.

17 Appendix L Flood Risk in County Durham

Information regarding minor watercourses flowing through Willington, which are listed below, have been provided from previous SFRAs:

Unnamed watercourse flows through northwestern part of Willington before discharging into Willingron Burn by Hunwick Lane; and Shiny Beck flows north to south through the eastern part of Willington.

The risk of flooding from these watercourses is unknown.

11.2.3 Surface Water Flood Risk

Areas of Central Willington, around the A690, are susceptible to surface water flooding from rainfall events with a 5 % AEP. Further areas to the north and south are at risk of flooding during a 2 % AEP event or less. Willington will likely experience flood depth in the range of 0 m to 0.25 m during a 1 % AEP event. Flood depth is likely to be greater in low lying areas of central Willington which may be in the order of 0.5 m to 1 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

11.3 Map C4 (Witton Park)

11.3.1 Historical Flooding

There is no record of historical flooding in Witton Park.

11.3.2 Fluvial & Tidal Flood Risk

The River Wear is situated north of Witton Park and flows east, towards Bishop Auckland. The settlement lies outside of the River Wear Flood Zones and therefore not considered to be at risk of fluvial flooding.

Information regarding minor watercourses flowing through Witton Park, which are listed below, have been provided from previous SFRAs:

Unnamed watercourse flows through eastern part of Witton Park.

The risk of flooding from this watercourse is unknown.

11.3.3 Surface Water Flood Risk

Much of Witton Park is not at risk or considered low risk in terms of surface water flooding. The railway station situated at the northern extent is at risk of flooding during a storm event with a less than 1 % AEP. Southwards and towards Woodside some small areas may be at risk of flooding during a 5 % AEP event or less. Flood depth is likely to be in the range of 0 m to 0.25 m during a 1 % AEP event but may reach 0.5 m in some low lying areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

18 Appendix L Flood Risk in County Durham

11.4 Map C4 (Spennymoor)

11.4.1 Historical Flooding

There is no record of historical flooding in Spennymoor.

11.4.2 Fluvial & Tidal Flood Risk

The River Wear is situated north of Spennymoor and flows north, towards Durham. The settlement lies outside of the River Wear Flood Zones, however Valley Burn and its tributaries flow in a northwesterly direction from the northern area of Spennymoor towards the River Wear. Valley Burn poses a flood risk to the northern area of Spennymoor by the Sewage Works. Some of the Valley Burn tributaries that run through northern Spennymoor have not been assessed by the EA and the risk of flooding is unknown.

11.4.3 Surface Water Flood Risk

Small areas of central Spennymoor, along the A688 towards Mount Pleasant and Tudhoe, are susceptible to surface water flooding from rainfall events with a 5 % AEP. Throughout the rest of the settlement there are areas at risk of surface water flooding during a 2 % or less AEP event. The aforementioned areas at greater risk of flooding may experience greater flood depth during a 1 % AEP event. Notably the area east of the intersection between Weardale Street and the A688 may experience flood depth in excess of 1m. For much of the settlement surface water flooding is unlikely to exceed 0.25 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

11.5 Mapc C4 (Brandon)

11.5.1 Historical Flooding

There are two recorded flood incident locations in Brandon. Leesfield Road and Leesfield Gardens have been affected by flooding three times in the last 18 years due to drainage capacity issues.

11.5.2 Fluvial & Tidal Flood Risk

According to EA Flood Zones Brandon is not currently at risk from fluvial flooding.

A couple of unnamed watercourses flow from northwest to southeast, from central and northern parts of Brandon, before discharging into the River Browney east of the settlement. The risk of flooding from these watercourses is unknown.

11.6 Surface Water Flood Risk

Small areas of Brandon that are susceptible to surface water flooding are typically at risk from rainfall events with a 5 % AEP or less. Flood depth is unlikely to exceed 0.5 m during a 1 % AEP event.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

19 Appendix L Flood Risk in County Durham

11.7 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology of variable permeability, overlain by a till soil layer within the river valley (see Figure 6). The topography falls relatively steeply towards the river, with relatively flat ground levels evident along the River Wear corridor (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils on the higher ground are low permeability drift deposits. Within the lower lying areas, the soils are typically deep and coarse textured, with a relatively high permeability. For this reason, infiltration devices and permeable surfaces should function efficiently within the lower lying central areas of this map window (surrounding the River Wear), however care will need to be taken during the design process to ensure that the adopted SUDS techniques are suitable within the local topography (i.e. taking account of any local steep slopes). Infiltration techniques are likely to be less effective within the more elevated areas to the northwest (Stanley Crook) and southeast (Coundon). Basins, ponds and tanked systems are more suitable in this area, and once again careful consideration should be taken of the steep topography.

20 Appendix L Flood Risk in County Durham

12.0 MAP C5

12.1 Map C5 (Peterlee)

12.1.1 Historical Flooding

Only a single flooding incident has been reportedin Peterlee. The incident occurred to the west of Peterlee in Shotton Colliery as a result of maintenance issues which led to localised flooding.

12.1.2 Fluvial & Tidal Flood Risk

Castle Eden Burn flows along the southern periphery of Peterlee, from west to East. The Flood Zone extents indicate that only the south western extent of Peterlee, towards Wheatley Hill is at risk of flooding. At least six tributaries of Castle Eden Burn flow southwards from Peterlee, however the flood extents for these minor watercourses have not been mapped by the EA and may pose a flood risk.

12.1.3 Surface Water Flood Risk

Small areas throughout Peterlee are susceptible to surface water flooding, typically rainfall events with a 10 % AEP or less. Westwards, towards Shotton Colliery, the risk of flooding reduces. More extensive flooding may occur immediately north of St Cuthberts Church during an intense event with a less than 1 % AEP. Flood depth throughout much of Peterlee during a 1 % AEP is likely to range from 0.5 m to 1 m. Flood depth in some areas of central and southern Peterlee may exceed 1 m in some areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

12.2 Map C5 (Coxhoe, Trimdon, Trimdon Colliery, Bowburn, Wingate)

12.2.1 Historical Flooding

Various locations throughout Map C5, including Bowburn, Trimdon Colliery and Coxhoe have experienced flooding as a result of surface water runoff and drainage issues.

12.2.2 Fluvial & Tidal Flood Risk

Excluding Peterlee and southern Wingate there are no settlements within Map C5 identified as being at risk of fluvial flooding. Crimdon Beck runs east through southern Wingate and a few properties appear to be within Flood Zone 3.

There are numerous minor watercourses throughout Map C5 that have not been mapped by the EA and may pose a flood risk to nearby areas.

21 Appendix L Flood Risk in County Durham

12.2.3 Surface Water Flood Risk

Various locations throughout Map C5, including Bowburn, Trimdon Colliery and Coxhoe are susceptible to surface water flooding, typically from rainfall events with a 5 % AEP event or less. Depending on the local topography, flood depth during a 1 % AEP event may range between 0.5m and 1m in some small areas of the abovementioned settlements.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

12.3 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology that is highly permeable (see Figure 6). The topography is relatively undulating, falling away to the west from an area of higher ground (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils within this area of variable permeability, from low to intermediate. For this reason, infiltration devices and permeable surfaces may function effectively within this area, however local geological conditions will need to be considered as part of the design process to ensure the suitability of the soils within the site. Basins, ponds & tanked systems will all function effectively in this area. The undulating nature of the local topography would seem to indicate that local changes in ground level are unlikely to pose a design constraint. Finally, whilst there is no immediate evidence of high groundwater levels causing groundwater flooding in this area, a local investigation should be carried out as part of the design process to ensure that this risk is not exacerbated if considering infiltration techniques.

22 Appendix L Flood Risk in County Durham

13.0 MAP C6 (EAST COAST)

13.1 Historical Flooding

There are no recorded incidents of flooding.

13.2 Fluvial & Tidal Flood Risk

Crimdon Beck and Castle Eden Burn flow across map C6 from west to east, discharging into the North Sea. According to EA Flood Zones Crimdon Beck and Castle Eden Burn do not pose a flood risk to any settlements located within Map C6.

A number of unnamed minor watercourses are present in Map C6, however Flood Zones for these have not been mapped by the EA and therefore flood risk is unknown.

13.3 Surface Water Flood Risk

Areas susceptible to surface water flooding, which include Hesleden and Blackhall Colliery are typically at risk from rainfall events with a 5 % or less AEP. Flood depth during a 1 % AEP event is typically less than 0.25 m, however in Hesllden and Blackhall Colliery flooding may be as deep as 1 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

13.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology that is highly permeable (see Figure 6). The topography is relatively undulating throughout the area, falling towards the coastal fringe (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils within this area of variable permeability, from intermediate to high. For this reason, infiltration devices and permeable surfaces may function effectively within this area, however local geological conditions will need to be considered as part of the design process to ensure the suitability of the soils within the site. Basins, ponds & tanked systems will all function effectively in this area. The undulating nature of the local topography indicates that local changes in ground level are unlikely to pose a design constraint for SUDS. Finally, whilst there is no immediate evidence of high groundwater levels causing groundwater flooding in this area, a local investigation should be carried out as part of the design process to ensure that this risk is not exacerbated if considering infiltration techniques.

23 Appendix L Flood Risk in County Durham

14.0 MAP D1 (GRAINS O’ TH’ BECK)

14.1 Historical Flooding

There are no records of historical flooding located in Map D1.

14.2 Fluvial & Tidal Flood Risk

There are no major settlements within Map D1, therefore flood risk in the area is minimal.

14.3 Surface Water Flood Risk

There are no major settlements within Map D1, therefore surface water flood risk in the area is minimal.

14.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground (see Figure 6). The elevated topography is relatively consistent across the map area (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils have a relatively high organic content. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable however an impermeable lining will be required. Tanked systems will function effectively in this area. In both instances, careful consideration will need to be taken of buoyancy (of the structure) and the changes in surrounding groundwater levels during saturated conditions.

24 Appendix L Flood Risk in County Durham

15.0 MAP D2 (MICKLETON & MIDDLETON-IN-TEESDALE)

15.1 Historical Flooding

Most of the historical flood incidents were caused by surface water runoff from nearby fields. Flooding in Mickleton is known to have occurred since water levels in the nearby watercourse prevent highway drains discharging.

15.2 Fluvial & Tidal Flood Risk

The River Tees flows from northwest to southeast across Map D2. The river passes along the southern perimeter of Middleton Teesdale and northern perimeter of Cotherstone, posing a flood risk to these nearby areas. Tributaries of the River Tees also pose a flood risk to the settlements they flow through. Hudeshope Beck flows through the centre of Middleton in Teesdale and the confluence with the River Tees is located west of the bridge on Bridge Street. Wester Beck/Flushlemere Beck flows through Bowlees, a small settlement northwest of Middleton in Teesdale. Ettersgill Beck, located east of Ettersgill may pose a flood risk to a few properties as it approaches the River Tees confluence. The River Balder flows east from Hury Reservoir and along the northern perimeter of Cotherstone as it approaches the confluence with the River Tees. The northern extent of Cotherstone is at risk of flooding from the River Tees and River Balder.

Selset Reservoir, Grassholme Reservoir, Balderhead Reservoir, Blackton Reservoir and Hury Reservoir each pose a significant residual flood risk to properties downstream and downgradient.

15.3 Surface Water Flood Risk

Areas susceptible to surface water flooding, which include Middleton in Teesdale and Mickleton are typically at risk from rainfall events with a 2 % or less AEP. Flood depths during a 1 % AEP event may be as deep as 1 m but generally do not exceed 0.25 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

15.4 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology of variable permeability, overlain by a till soil layer (see Figure 6). The topography falls relatively steeply from west to east towards the River Tees (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils are primarily low permeability drift deposits. Soils along the River Tees corridor are classified as ‘negligibly’ permeable. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

25 Appendix L Flood Risk in County Durham

16.0 MAP D3 (STAINTON & STAINDROP)

16.1 Historical Flooding

Historical flooding has been recorded in Lynesack, Copley, The Slack, Ramshaw, Cockfield, Evenwood and Staindrop. Limited information is available regarding the incidents in Lynesack and Copley. The Slack is known to have flooded in the past but now benefits from a flood wall with a 100 year SoP. The records for Ramshaw are all associated with fluvial flooding from the River Gaunless in 1993, 2000, 2001, 2004 and 2009. The area benefits from flood defences.

16.2 Fluvial & Tidal Flood Risk

Langley Beck, an unnamed watercourse and Sudburn Beck flow west to east through northern, central and south eastern parts of Staindrop respectively. They each pose a flood risk to Staindrop residential and commercial properties in Staindrop. An extensive area of Flood Zone 3a is located at the eastern extent of Staindrop, upstream of the confluence between Langley Beck and Sudburn Beck. Areas along the river bank of Hindon Beck in Copley, Grewburn Beck in Butterknowle and the River Gaunless in The Slack may be at risk of fluvial flooding. Three minor watercourses flow north to south through South Side. Flood Zones for these watercourses have not been generated by the EA and therefore fluvial flood risk in South Side is unknown. The River Gaunless flows southwest to north northeast through Ramshaw and poses a risk to central Ramshaw. East of Ramshaw areas on the northern bank of the River Gaunless benefit from flood defences designed to a 50 year SoP. A buried concrete with a 200 year SoP protects Mill Cottages on the southern bank of the River Gaunless. Gordon Beck flows in a south easterly direction through Ramshaw and may pose a risk to residential properties in Ramshaw. Note however the Flood Zone does not follow the path of the watercourse, indicating certain properties may not be at risk.

Cockfield is not at risk of fluvial flooding.

16.3 Surface Water Flood Risk

Areas of settlements throughout Map D3, including Staindrop, Ramshaw, Cockfield, Stainton, Butterknowle and Evenwood are susceptible to surface water flooding. Such areas are typically at risk from rainfall events with a 5 % or less AEP. Flood depths during a 1 % AEP event will typically be less than 0.25 m but may reach 1 m in some low lying areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

16.4 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology and coal measures of variable permeability, overlain by a till soil layer (see Figure 6). The topography falls relatively steeply from west to east towards the River Tees (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils are low permeability drift deposits. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

26 Appendix L Flood Risk in County Durham

17.0 MAP D4

17.1 Map D4 (Bishop Auckland)

17.1.1 Historical Flooding

Bishop Auckland has regularly experienced flooding from a variety of sources. Major fluvial flooding occurred in 2000, flooding approximately 400 properties in Bishop Auckland. This subsequently led to the development of a flood storage reservoir in Spring Gardens with a 200 year SoP which mitigates flow along the River Gaunless through Bishop Auckland. An extensive number of properties in West Auckland were also flooded in 2003. Surface water flooding has been identified as a problem in Eldon, east of South Church. Sources include blocked drains and runoff from nearby fields.

17.1.2 Fluvial & Tidal Flood Risk

The River Gaunless flows eastwards through West Auckland before turning northwards and flowing through the eastern part of Bishop Auckland. The River Gaunless and its tribuatries Oakley Cross Beck and Dene Beck pose a serious fluvial flood risk to southern and eastern parts of Bishop Auckland. A significant area of West Auckland and South Church are located within Flood Zone 3.

Bishop Auckland benefits from the River Gaunless Flood Alleviation Scheme. Flow along the River Gaunless through Bishop Auckland is mitigated by the Spring Gardens flood storage reservoir located west of West Auckland. The reservoir is a 12 m clay lined dam which provides a 200 year SoP. According to previous SFRAs discharge is restricted to a 6.67 % annual exceedance probability (AEP) event for events up to the 0.5 % AEP event. Additional defences located downstream of Spring Gardens include: a flood bank and floodwall in West Auckland; floodwalls and flood banks in South Church; and a floodwall and flood bank protect a playing field and cemetery east of the A689. Each of the afromentioned flood defences provide at least a 50 year SoP. Flood defences are also located along Oakley Cross Beck in West Auckland, providing a 200 year SoP.

According to a previous SFRA, Coal Burn flows west to east through the northwestern part of Bishop Auckland to the River Wear. The flood risk posed by Coal Burn has not been assessed and therefore unknown.

17.1.3 Surface Water Flood Risk

Much of central Bishop Auckland and St Helen Auckland are susceptible to surface water flooding. Surface water flooding poses a risk to these areas during rainfall events with a 5 % or less AEP. Flood depth during a 1 % AEP will generally be less than 0.5 m, however some areas, notably central Bishop Auckland and St Helen Auckland may experience flood depths in excess of 1 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points

27 Appendix L Flood Risk in County Durham

17.2 Map D4 (Newton Aycliffe)

17.2.1 Historical Flooding

Only a few flooding incidents have been recored in Newton Aycliffe, largely towards the northern extent of the town. Details are very limited but include surface water flooding of Burn Lane from fields to the north and an incident along Woodham Burn is understood to have been caused by a culvert. Insufficient capacity or a blockage are the likely causes. East of Aycliffe Industrial Estate, the River Skerne was close to breaching during November 2000.

17.2.2 Fluvial & Tidal Flood Risk

Woodham Burn flows eastwards from Shildon before turning northeast through the centre of Newton Aycliffe and exiting the settlement to the north and eventually discharging into the River Skerne. Woodham Burn poses a risk to properties along its banks. The risk of flooding is notably more extensive in the west by Williamfield Way. Much of this area has been left as recreational land and school playing fields, however the school and a number of residential properties are located within Flood Zone 2. A tributary of Woodham Burn, an unnamed watercourse along the western perimeter of the settlement, may pose a flood risk to school facilities on Greenfield Way. An unnamed watercourse flowing through Newton Aycliffe from Heighinton Station to the treatment works before discharging into the River Skerne is a flood risk to areas along its reach, particularly the treatment works and nearby residential properties.

17.2.3 Surface Water Flood Risk

The northern extent of the settlement is at greater risk of flooding, where surface water flooding is likely to be more frequent and deeper in comparison to the south. Flooding may occur following a 5 % AEP event in both the north and south of Newton Aycliffe, but a greater number of areas in the north are at risk. Flood depth during a 1 % AEP is typically estimated to be less than 0.25 m but some areas, notably the northern extent of the settlement, may experience flooding up to 1 m deep.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

17.3 Map D4 (Shildon)

17.3.1 Historical Flooding

Sewer capacity in Central Shildon has been identified as a cause of flooding. the Beck which runs through Hackwark Park west of the train station causes flash flooding following heavy rainfall. No properties are understood to have been affected. West road carriageway has been closed twice in the last 5 years due to surface water runoff from nearby fields. Excluding the major settlements, there are no additional records of flooding.

17.3.2 Fluvial & Tidal Flood Risk

An unnamed watercourse poses a flood risk to the train line running through Shildon and nearby properties. It is unclear if this watercourse is part of the watercourse in Hackwark Park which is known to have flooded. Langton Beck and Killerby Beck flow south east towards the River Tees and pose a flood risk to Headlam and Killerby respectively.

28 Appendix L Flood Risk in County Durham

Rushyford Beck flows south east through Rushyford Beck and poses a fluvial flood risk to nearby properties.

17.3.3 Surface Water Flood Risk

Areas of Shildon that are susceptible to surface water flooding are typically at risk from rainfall events with a 5 % or less AEP and flood depth may be up to 1 m in some areas during a 1 % AEP event.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

17.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology that is highly permeable (see Figure 6). The topography is relatively undulating (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils within this area of variable permeability, from low to intermediate. For this reason, infiltration devices and permeable surfaces may function effectively within this area, however local geological conditions will need to be considered as part of the design process to ensure the suitability of the soils within the site. Basins, ponds & tanked systems will all function effectively in this area. The undulating nature of the local topography would seem to indicate that local changes in ground level are unlikely to pose a design constraint. Finally, whilst there is no immediate evidence of high groundwater levels causing groundwater flooding in this area, a local investigation should be carried out as part of the design process to ensure that this risk is not exacerbated if considering infiltration techniques.

29 Appendix L Flood Risk in County Durham

18.0 MAP D5 (SEDGEFIELD, BRADBURY AND MORDON)

18.1 Historical Flooding

Only two incidents of flooding have been recorded in Map D5, each of which have occurred outside any notable settlements. Details are very limited but occurred outside of the Flood Zones signifying a drainage issue.

18.2 Fluvial & Tidal Flood Risk

Sedgefield, Bradbury and Mordon are not at risk of fluvial flooding.

18.3 Surface Water Flood Risk

Areas of Sedgefield, Bradbury and Mordon that are susceptible to surface water flooding are typically at risk from rainfall events with a 5 % AEP. Central and western Sedgefield in particular have a number of areas prone to localised flooding during such an event. Flood depth in central Sedgefield is likely to be in excess of 0.5 m and may exceed 1 m during a 1 % AEP event. Flood depth in Mordon is unlikely to exceed 0.5 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points

18.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology that is highly permeable (see Figure 6). The topography is relatively flat throughout the area (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils within this area of variable permeability, from intermediate to high, however clay lenses are evident in the geological mapping. For this reason, infiltration devices and permeable surfaces may function effectively within this area, however local geological conditions will need to be considered as part of the design process to ensure the suitability of the soils within the site. Basins, ponds & tanked systems will all function effectively in this area. The relatively flat nature of the local topography indicates that local changes in ground level are unlikely to pose a design constraint for SUDS. Finally, whilst there is no immediate evidence of high groundwater levels causing groundwater flooding in this area, a local investigation should be carried out as part of the design process to ensure that this risk is not exacerbated if considering infiltration techniques.

30 Appendix L Flood Risk in County Durham

19.0 MAP E1 (BOWES & GILMONBY)

19.1 Historical Flooding

There are no records of historical flooding.

19.2 Fluvial & Tidal Flood Risk

The River Greta flows west to east and dissects Bowes and Gilmonby. However, the River Greta does not pose a risk to these settlements.

19.3 Surface Water Flood Risk

The extent of surface water flooding in Map E1 is minimal and typically occurs during events with less than a 1 % AEP, however localised flooding in Bowes and Gilmonby may occur during less intense storms with a 2 % AEP. Flood depth will largely remain below 0.25 m during a 1 % AEP event but may reach 0.5 m in some low lying areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

19.4 SUDS Suitability (Topography & Geology)

This area is characterised by underlying limestone geology of variable permeability, overlain by a peat soil layer at higher ground and till deposits in the river valleys (see Figure 6). The elevated topography is relatively consistent across the map area, with ground levels falling relatively rapidly towards the tributaries of the River Tees to the east (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) indicates that soils throughout the more elevated areas of this map window have a relatively high organic content. Whilst permeable, peaty soils are susceptible to becoming ‘super saturated’ resulting in localised flooding and instability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area. Basins and ponds may be suitable, however in the peat soil areas (i.e. on higher ground) an impermeable lining will be required. Tanked systems will function effectively throughout this area. Careful consideration will need to be taken of buoyancy and obstructions to lateral water movement within the peat layer in elevated areas. Finally, the adopted design must take into account the steep topography to ensure effective implementation.

31 Appendix L Flood Risk in County Durham

20.0 MAP E2

20.1 Map E2 (Barnard Castle)

20.1.1 Historical Flooding

Three flooding incidents along the River Tees in Barnard Castle have been attributed to fluvial flooding, however no further information is available. Newgate and the Granary were affected by flooding due to insufficient sewer capacity. Runoff from fields between Lartington and Barnard Castle have caused flooding along the B6277.

20.1.2 Fluvial & Tidal Flood Risk

The western extent of Barnard Castle features a number of confluences with the River Tees and consequently poses a flood risk. Deepdale Beck flows eastwards, skirting the young offenders institiute before dischring into the River Tees. Black Beck flows along the northern periphery of Barnard Castle and poses a risk to a small number of properties situated close to its banks. The most significant risk appears to be from the River Tees where a number of residential and commercial properties between the B6277 amd East Lendings are located in Flood Zone 3.

20.1.3 Surface Water Flood Risk

Southern Barnard Castle is at risk of surface water flooding following storm events with a 5 % AEP or less. Flood depth during a 1 % AEP event would typically be less than 0.25 m but may exceed 0.5 m in some areas.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

20.2 Map E2 (Ovington)

20.2.1 Historical Flooding

The majority of flooding incidents are located in Ovington and along the River Tees, however they are attributed to surface water runoff issues.

20.2.2 Fluvial & Tidal Flood Risk

Hutton Beck may pose a risk to properties along the northern perimeter of Hutton Magna. Whorlton and Ovington are located outside of the Flood Zones and not at risk of fluvial flooding from the River Tees due to the steep river banks. Barningham is not at risk of flooding, however some outlying properties are located within the Flood Zone of Nor Beck. Boldron is not a risk of fluvial flooding. Tutta Beck confluence with the River Greta at Greta Bridge may be a flood risk to nearby properties. The watercourse flowing northwards through Peak Hole, understood to be Stang Gill, may be a flood risk.

32 Appendix L Flood Risk in County Durham

20.2.3 Surface Water Flood Risk

Surface water flooding poses a risk to settlements throughout Map E2. At the northern extent of Whorlton, towards Grange Farm, surface water flooding poses a risk during a 5 % AEP rainfall event and may be up to 1 m deep during a 1 % AEP event. Barningham and Ovington are also at risk of localised surface water flooding to a similar degree.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

20.3 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology of variable permeability, overlain by a till soil layer (see Figure 6). The topography falls relatively steeply from west to east towards the River Tees (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils are low permeability drift deposits. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, however careful consideration will need to be taken of the steep topography to ensure their effective implementation. Tanked systems will function effectively in this area.

33 Appendix L Flood Risk in County Durham

21.0 MAP E3 (GAINFORD AND WINSTON)

21.1 Historical Flooding

Historical flooding has only been reported in the vicinity of Gainford, however details of the incidents are limited. Balmer Lane, Eden Lane and Waters End are known to have been affected.

21.2 Fluvial & Tidal Flood Risk

The River Tees flows northwards along the eastern perimeter of Winston before turning eastwards and along the southern boundary of Gainford. Fluvial flood risk is more extensive in Gainford due to the proximity of the settlement to the water course and extent of the Flood Zones. Much of the area between the A67 and the River Tees is within Flood Zone 2 or 3 and therefore at risk of flooding.

21.3 Surface Water Flood Risk

Winston and Gainford are both at risk of surface water flooding during a 5 % AEP event and may experience flood depths up to 1 m during a 1 % AEP event depending on the local topography. Typical flood depth during such an event is estimated to be less than 0.25 m.

Areas located along overland flow paths are at risk of flooding due to the concentration of surface water runoff along topographical low points.

21.4 SUDS Suitability (Topography & Geology)

This area is characterised largely by underlying limestone geology of variable permeability, overlain by a till soil layer (see Figure 6). The topography is relatively undulating, falling from west to east towards the River Tees (see Figure 5). A review of published Groundwater Vulnerability mapping (Environment Agency) within this area indicates that soils typically exhibit a low permeability. For this reason, infiltration devices and permeable surfaces are unlikely to function efficiently in this area of County Durham. Basins and ponds may be suitable, subject to local ground conditions within the site. Tanked systems will function effectively in this area.

34 ¶

LEGEND

County Boundary

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Project Durham County Strategic Flood Risk Assessment (SFRA) Title Locality Plan

Created by Project Manager Reviewer File No.RE KD Project? No. DateSept 09 Scale? 09514100112 Size Status A3 1:350,000 For Information Drawing No. Rev 1 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ¶

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Topography (mAOD) 850

0

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LEGEND

OSextent

County Boundary

Solid DINANTIAN ROCKS (UNDIFFERENTIATED)

KELLAWAYS FORMATION AND OXFORD CLAY FORMATION (UNDIFFERENTIATED)

LIAS GROUP

MILLSTONE GRIT GROUP [SEE ALSO MIGR]

PENNINE LOWER COAL MEASURES FORMATION AND SOUTH WALES LOWER COAL MEASURES FORMATION (UNDIFFERENTIATED)

PENNINE MIDDLE COAL MEASURES FORMATION AND SOUTH WALES MIDDLE COAL MEASURES FORMATION (UNDIFFERENTIATED)

PENNINE UPPER COAL MEASURES FORMATION

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UNNAMED IGNEOUS INTRUSION, CARBONIFEROUS TO PERMIAN

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DRIFT GEOLOGY NOT MAPPED [FOR DIGITAL MAP USE ONLY]

GLACIAL SAND AND GRAVEL

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PEAT

RAISED MARINE DEPOSITS (UNDIFFERENTIATED)

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TILL

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Notes 6 - This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead may lead to prosecution or civil proceedings. 100049055 (2009). Berkshire SL6 8BY +44 (0)1628 586 200 7a ¶ 7b 7c

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Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Defences & Flood Hazard Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:75,000 For Information Drawing No. Rev - Notes 7a This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 7a ¶ 7b 7c

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Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Defences & Flood Hazard Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:75,000 For Information Drawing No. Rev - Notes 7b This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 7a ¶ 7b 7c

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Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Defences & Flood Hazard Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:75,000 For Information Drawing No. Rev

Notes 7c - This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ¶

Derwent Reservoir

Sikehead Dam Hisehope Reservoir LEGEND Burnhead Dam Corbitmere Dam Reservoirs Waskerley Reservoir County Boundary

Tunstall Reservoir

Burnhope Reservoir

Hurworth Burn Reservoir

Crookfoot Reservoir

Cow Green Reservoir

Spring Gardens Clay Filled Dam

Fish Lake Grassholme Reservoir 0369

Selset Reservoir Kilometres

Hury Reservoir Client Balderhead Reservoir Durham County Council Blackton Reservoir Project Durham County Strategic Flood Risk Assessment (SFRA) Title Reservoirs

Created by Project Manager Reviewer File No.RE KD Project? No. DateSept 09 Scale? 09514100112 Size Status A3 1:250,000 For Information Drawing No. Rev

Notes 8 - This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead may lead to prosecution or civil proceedings. 100049055 (2009). Berkshire SL6 8BY +44 (0)1628 586 200 ¶

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Project Durham County Strategic Flood Risk Assessment (SFRA) Title DG5 Register Summary (Northumbrian Water) Created by Project Manager Reviewer File No.RE KD Project? No. DateSept 09 Scale? 09514100112 Size Status A3 1:250,000 For Information Drawing No. Rev - Notes 13 This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. permission of Ordnance Survey on behalf of the Controller of Clyde House Her Majesty's Stationary Office © Crown copyright. Reform Road Unauthorised reproduction infringes Crown copyright and Maidenhead Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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Flood Zone 3a + Climate Change

Durham County

! ! !

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) ! Title Climate Change Flood Zone Extents - Sheet A1

Created by Project Manager Reviewer ! ! File No.RE KD ProjectKD No. 04/02/2010Date ! ! Scale- 09514100112 ! ! !Size Status ! A3 1:50,000 For Information ! Drawing No. Rev ! J1 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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OS map not available Legend ! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

!

00.511.522.5

Kilometres ! Client ! ! Durham County Council ! Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet A2 Created by Project Manager Reviewer ! ! ! File No. KD ProjectKD No. 04/02/2010Date ! RE ! Scale ! ! ! - 09514100112 ! Size Status ! A3 1:50,000 For Information ! Drawing No. Rev ! ! J2 - Notes ! ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of ! Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or !civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet B1 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J3 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet B2 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J4 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 ! ! ! ! ! A1 A2 ! ¶ ! B1 B2 B3 B4 B5 C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5 ! E1 E2 E3 ! ! Legend

! Historical Flooding Incidents ! !

! Flood Defences ! ! ! ! ! Flood Zone 3a ! ! Flood Zone 3a + Climate Change ! Durham County !

! !! !! ! ! ! !! ! ! !

!

!

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet B3 ! Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J5 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! ! ! ! ! ! A1 A2 ! ! ¶ ! ! B1 B2 B3 B4 B5 ! C1 C2C3 C4 C5 C6 D1 D2D3 D4 D5 ! ! ! ! E1 E2 E3 ! ! ! ! ! ! ! ! !! ! ! ! Legend ! ! ! ! Historical Flooding Incidents ! ! ! ! ! ! Flood Defences

! Flood Zone 3a

! Flood Zone 3a + Climate Change !! Durham County

!

! ! ! ! ! ! !

! ! ! ! ! ! !!

! ! ! ! ! ! ! ! ! !! 00.511.522.5 ! !!! !!!! ! ! ! !!! ! !! ! Kilometres ! ! !!! Client ! ! ! !! Durham County Council ! ! !Project ! ! Durham County Strategic Flood ! ! ! Risk Assessment (SFRA) !! ! Title ! ! ! Climate Change Flood Zone Extents - Sheet B4 ! ! !! ! Created by Project Manager Reviewer ! ! ! ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status ! ! A3 1:50,000 For Information ! Drawing No. Rev ! ! ! ! ! J6 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. ! Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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! Flood Defences ! ! ! Flood Zone 3a

Flood Zone 3a + Climate Change ! ! ! Durham County

!

!

! !

!

!

! 00.511.522.5 ! ! !! ! ! Kilometres Client Durham County Council ! Project ! Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet B5 ! Created by Project Manager Reviewer ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev

! J7 - Notes ! This map is based upon Ordnance Survey material with the ! © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

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E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet C1 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 ! Size Status A3 1:50,000 For Information Drawing No. Rev J8 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5 ! E1 E2 E3

! Legend ! !! ! ! ! Historical Flooding Incidents

Flood Defences ! ! Flood Zone 3a

Flood Zone 3a + Climate Change

! ! Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet C2 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J9 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

! Flood Zone 3a ! ! ! ! Flood Zone 3a + Climate Change

! ! Durham County !

! ! ! !

!

00.511.522.5

! Kilometres ! ! Client ! ! ! ! Durham County Council ! ! Project ! Durham County Strategic Flood Risk Assessment (SFRA) ! Title ! ! Climate Change Flood Zone Extents - Sheet C3 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date ! Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J10 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! ! ! ! ! A1 A2 ! ! ! ¶ ! B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6 ! D1 D2D3 D4 D5

E1 E2 E3

! ! Legend

! Historical Flooding Incidents ! ! Flood Defences ! ! ! ! Flood Zone 3a ! ! Flood Zone 3a + Climate Change

! Durham County

!

! ! ! ! ! ! ! ! ! !

! ! !

!

! !

00.511.522.5

! Kilometres ! ! Client ! ! ! Durham County Council Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet C4 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 ! Size Status A3 1:50,000 For Information Drawing No. Rev ! J11 - Notes ! ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). ! SL6 8BY +44 (0)1628 586 200 A1 A2 ! ! ¶ ! ! B1 B2 B3 B4 B5 ! C1 C2C3 C4 C5 C6 ! ! D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents ! ! ! Flood Defences ! ! ! ! Flood Zone 3a

! Flood Zone 3a + Climate Change

Durham County !

!! ! ! ! ! !

!

00.511.522.5

Kilometres Client ! Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet C5 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale ! - 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J12 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences ! Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet C6 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J13 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

OS map not available Legend ! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

! ! !

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer ! ! File No. KD ProjectKD No. 04/02/2010Date ! RE ! ! Scale- 09514100112 ! ! !Size Status ! A3 1:50,000 For Information ! Drawing No. Rev ! B1 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 ! A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet D1 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J14 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend ! ! Historical Flooding Incidents ! ! Flood Defences ! Flood Zone 3a ! ! Flood Zone 3a + Climate Change

Durham County

! ! !

!

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet D2 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J15 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

OS map not available Legend ! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

!

00.511.522.5

Kilometres ! Client ! ! Durham County Council ! Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer ! ! ! File No. KD ProjectKD No. 04/02/2010Date ! RE ! ! Scale- 09514100112 ! ! ! ! Size Status ! A3 1:50,000 For Information ! Drawing No. Rev ! ! B2 - Notes ! ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of ! Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or !civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 !

A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents

! Flood Defences !! ! ! ! Flood Zone 3a

! Flood Zone 3a + Climate Change ! ! Durham County

!

!

00.511.522.5

! Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet D3 Created by Project Manager Reviewer ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J16 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. ! Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !

A1 A2 ! ¶ ! ! B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6 ! ! ! D1 D2D3 D4 D5 E1 E2 E3 ! ! ! !! ! ! Legend

! Historical Flooding Incidents ! ! ! ! ! Flood Defences ! ! ! !! ! ! ! ! Flood Zone 3a ! Flood Zone 3a + Climate Change ! Durham County

!

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet D4 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information ! Drawing No. Rev J17 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes! Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 B1 B2 B3 B4 B5 C1C2C3 C4 C5 C6 D1 D2D3 D4 D5 E1 E2 E3

Legend

Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents - Sheet B1 Created by Project Manager Reviewer File No.RE KD Project? No. Date? Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B3 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5 ! ! E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet D5 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J18 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2 ¶ B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 3a

! Flood Zone 3a + Climate Change

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet E1 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J19 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B4 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 A1 A2

B1 B2 B3 B4 B5

C1 C2C3 C4 C5 C6

D1 D2D3 D4 D5

E1 E2 E3

Legend

Historical Flooding Incidents

Flood Defences

Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

0 0.5 1 1.5 2 2.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet E2 Created by Project Manager Reviewer File No.RE KD Project? No. Date? Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J20 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! A1 A2 ¶ B1 B2 B3 B4 B5 ! C1 C2C3 C4 C5 C6 ! D1 D2D3 D4 D5

E1 E2 E3

Legend

! ! Historical Flooding Incidents ! !! ! Flood Defences ! Flood Zone 3a

Flood Zone 3a + Climate Change

Durham County

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Climate Change Flood Zone Extents - Sheet E3 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev J21 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! ! ! ! ! B1 B2 ! ¶ B3 B4 B5 B6 B7 ! B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18 ! B19 B20 B21

! ! Legend ! ! ! Historical Flooding Incidents

! Flood Defences ! ! ! ! ! Flood Zone 2 ! ! Flood Zone 3a ! Zone 3b ! Modelled by EA

! Water Storages Reservoirs !! !! ! ! Coarse SFRA Modelling ! !! ! ! ! Rural Areas Durham County !

!

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents ! Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B5 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! ! ! ! ! ! B1 B2 ! ! ¶ B3 B4 B5 B6 B7 ! ! B8B9 B10 B11 B12 B13 ! B14 B15B16 B17 B18 ! ! ! ! B19 B20 B21 ! ! ! ! ! ! ! ! !! ! ! ! Legend ! ! ! ! ! ! Historical Flooding Incidents ! ! ! Flood Defences ! Flood Zone 2

! Flood Zone 3a !! Zone 3b Modelled by EA ! Water Storages Reservoirs

! ! Coarse SFRA Modelling

! ! Rural Areas ! ! ! Durham County

! ! ! ! ! ! !!

! ! ! ! ! ! ! ! ! !! 00.511.522.5 ! !!! !!!! ! ! ! !!! ! !! ! Kilometres ! ! !!! Client ! ! ! !! Durham County Council ! ! !Project ! ! Durham County Strategic Flood ! ! ! Risk Assessment (SFRA) !! ! Title ! ! ! Flood Zone Extents ! ! !! ! Created by Project Manager Reviewer ! ! ! ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status ! ! A3 1:50,000 For Information ! Drawing No. Rev ! ! ! ! ! B6 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. ! Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

! B19 B20 B21

Legend

! Historical Flooding Incidents ! ! Flood Defences ! ! Flood Zone 2

! Flood Zone 3a ! ! Zone 3b Modelled by EA

! Water Storages Reservoirs

Coarse SFRA Modelling ! Rural Areas ! ! Durham County

!

!

! 00.511.522.5 ! ! !! ! ! Kilometres Client Durham County Council ! Project ! Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents ! Created by Project Manager Reviewer ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B7 - Notes ! ! ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 ! Size Status A3 1:50,000 For Information Drawing No. Rev B8 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18 ! B19 B20 B21

! ! !! Legend ! ! ! Historical Flooding Incidents

Flood Defences ! ! Flood Zone 2

Flood Zone 3a

! ! Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B9 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

! Flood Zone 2 ! ! ! ! Flood Zone 3a

! ! Zone 3b ! Modelled by EA

Water Storages Reservoirs

! Coarse SFRA Modelling

! Rural Areas ! ! Durham County

!

00.511.522.5

! Kilometres ! ! Client ! ! ! ! Durham County Council ! ! Project ! Durham County Strategic Flood Risk Assessment (SFRA) ! Title ! ! Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date ! Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B10 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! ! ! ! ! B1 B2 ! ! ! ¶ ! B3 B4 B5 B6 B7 B8B9 B10 B11 B12 B13 ! B14 B15B16 B17 B18

B19 B20 B21

! ! Legend

! Historical Flooding Incidents ! ! Flood Defences ! ! ! ! ! Flood Zone 2 ! Flood Zone 3a

! Zone 3b Modelled by EA ! Water Storages Reservoirs

! ! ! Coarse SFRA Modelling ! ! ! ! ! Rural Areas ! ! Durham County ! ! !

!

! !

00.511.522.5

! Kilometres ! ! Client ! ! ! Durham County Council Project Durham County Strategic Flood ! Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale ! - 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev ! ! B11 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). ! SL6 8BY +44 (0)1628 586 200 B1 B2 ! ! ¶ ! ! B3 B4 B5 B6 B7 ! B8B9 B10 B11 B12 B13 ! ! B14 B15B16 B17 B18 B19 B20 B21

Legend

! Historical Flooding Incidents ! ! ! Flood Defences ! ! ! ! Flood Zone 2

! Flood Zone 3a

! Zone 3b Modelled by EA !! ! ! Water Storages Reservoirs ! ! ! Coarse SFRA Modelling

Rural Areas

Durham County

!

00.511.522.5

Kilometres Client ! Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale ! - 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B12 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and ! Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY ! +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences ! Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B13 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B14 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend ! ! ! ! Historical Flooding Incidents

Flood Defences ! ! Flood Zone 2

! Flood Zone 3a

Zone 3b Modelled by EA ! ! Water Storages Reservoirs ! Coarse SFRA Modelling ! Rural Areas

Durham County

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B15 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

! Flood Defences !! ! ! ! Flood Zone 2 ! Flood Zone 3a ! ! Zone 3b Modelled by EA ! Water Storages Reservoirs ! Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

! Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer ! File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B16 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. ! Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !

B1 B2 ! ¶ ! ! B3 B4 B5 B6 B7 B8B9 B10 B11 B12 B13

! B14 B15B16 B17 B18 ! ! B19 B20 B21 ! ! ! !! ! ! Legend

! Historical Flooding Incidents ! ! ! ! ! ! ! ! Flood Defences !! ! ! ! ! Flood Zone 2 ! ! Flood Zone 3a Zone 3b

! Modelled by EA Water Storages Reservoirs

Coarse SFRA Modelling ! Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information ! Drawing No. Rev B17 - Notes ! © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes! Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18 ! ! B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling ! Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B18 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ B3 B4 B5 B6 B7

B8B9 B10 B11 B12 B13

B14 B15B16 B17 B18

B19 B20 B21

Legend

! Historical Flooding Incidents

Flood Defences

Flood Zone 2

! Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B19 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 B1 B2 ¶ ! B3 B4 B5 B6 B7 B8B9 B10 B11 B12 B13 ! B14 B15B16 B17 B18

! B19 B20 B21 !!

Legend ! ! ! Historical Flooding Incidents ! !! ! Flood Defences ! ! ! ! Flood Zone 2 ! ! Flood Zone 3a ! Zone 3b ! Modelled by EA

Water Storages Reservoirs

! Coarse SFRA Modelling

Rural Areas

Durham County !

!

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B20 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 ! B1 B2 ¶ B3 B4 B5 B6 B7 ! B8B9 B10 B11 B12 B13

! B14 B15B16 B17 B18

B19 B20 B21

Legend

! ! Historical Flooding Incidents ! !! ! Flood Defences ! Flood Zone 2

Flood Zone 3a

Zone 3b Modelled by EA

Water Storages Reservoirs

! Coarse SFRA Modelling

Rural Areas

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Flood Zone Extents Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev B21 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

OS map not available Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005 197 !( 2007 128 195 !( !( Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood 198285 Risk Assessment (SFRA) !( Title Historical Flooding

144 Created by Project Manager Reviewer 145 70 !( Date !( 130 30 File No.RE KD ProjectKD No. 04/02/2010 146 !( !( 71 Scale 31 13 - 09514100112 !( !( Size Status !( 133 A3 1:50,000 For Information 192 131 Drawing No. Rev !( 68 !( 132 28 A1 - Notes !( This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and 69 Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). !( SL6 8BY 29 +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

OS map not available Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005 197 !( 2007

Durham County 00.511.522.5

Kilometres 377 122 121!( Client !( 120 !( Durham County Council !( Project Durham County Strategic Flood 198285 Risk Assessment (SFRA) !( Title Historical Flooding 119 Reviewer 144 Created by Project Manager 145 70 !( !( Date !( 130 30 129 File No.RE KD ProjectKD No. 04/02/2010 146 !( !( 71 118 Scale 31 134 - 09514100112 !( !( !( 72 !( Size Status 133 !( 32 A3 1:50,000 For Information 131 74 Drawing No. Rev 328 !( 68 !( 34 !( 215 - 132 28 A2 Notes !( !( This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. 311 Clyde House permission of Ordnance Survey on behalf of the Controller of !( Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes69 Crown copyright and Berkshire may lead to prosecution or !(civil proceedings. 100049055 (2009). 325 SL6 8BY 29 329 350 !( +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A3 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project 250 Durham County Strategic Flood !( Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A4 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and 252 Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). !( +44 (0)1628 586 200 31 !( !( 13!( !( 133 192 131 A1 A2 !( 68 !( A3 A4 A5 A6 A7 ¶ 132 !( 28 A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18 69 !( 29 A19 A20 A21 2 !( 199 !(

191 295 Legend !( !( Historical Flooding Incidents 139 296 !( 292 !( !( !( 294 Council Consultation (2009) 67135 !( 137 293 136 !(27 !( !( !( Council Recorded (2008 SFRA) !(138 193 !( !( Town and Parish Council (2009)

194 Flood Defences !(

126 127 1963 !( 125!(!( 124 !( !( 141 1968 123 !( 202 298 140 142 !(!(143 !( !( 1978 !( 297 332 !( 196 !( 1995

299 !( 2000

2004

2005 300 !( 2007 301 !( Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding 205 !( Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A5 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 71 118 31 134 !( !( !( 72 !( 133 !( 32 131 74 A1 A2 328 68 !( 34 !( !( 215 A3 A4 A5 A6 A7 ¶ 132 !( 28 !( 311 A8A9 A10 A11 A12 A13 !( A14 A15A16 A17 A18 69 !( 325 29 329 350 !( A19 A20 A21 !( 110 !( 73 349 200 !( !( !( 213 !( 201 33 !( !( 116 78 115 !( 199 114 !( !( 214 !( 79 326 38 !( !( !( 75 112 !( 35 39 !( 327 Legend !( 113 !( 111 !( !(117 !( 77 324 !( Historical Flooding Incidents 37 !( !( 109 Council Consultation (2009) !( !( Council Recorded (2008 SFRA) 76 !( 107108 !( !(!( 36 Town and Parish Council (2009)

Flood Defences 352 !( 1963

216 1968 202 !( !( 330 178 1978 !( !( 375 25 80 !( 322 1995 !( 40 !( 93 2000 53 !( 6 366 3 7 !( !( !( 156 155 2004 !( !(!( 92 323 !( 51 52 91 2005 26 !( !( 170 203 168 150 2007 204 337 171 23 !( !( !( 162 18 4181 286 4 165 83 163 Durham County !( 43 19 24 173 154 !( !( 313 169!( !(!( 00.511.522.5 82 42 164 63 287 48 !( !(!(!( 166 103 !(!( !( 149 !( 153 88 !(!( !( 339 !( !(!(!( !( !(!( 99 (! Kilometres 172 !( !( 151 148 14 86 167 !(!(!( 21 59 Client !( !( 312 !( 314 376 46 160161 !(!( 315 Durham County Council 340 !(!( 104 !( 87 45 20 Project 320 101 !( !( 22 Durham County Strategic Flood 47 85 177 !( 12 !( 61 !( 84 Risk Assessment (SFRA) 11 !( 316 372 Title 9 174 !(!( 66 !( 13 44 !( 49 !( 89 !( Historical Flooding 205 !( 106 !(!( !( 319 338 50 !( 175 374 373 Created by Project Manager Reviewer 176 !( !( 10 !( 90 !( Date 179 File No.RE KD ProjectKD No. 04/02/2010 Scale- 09514100112 318 97 96 Size Status 57 !( !( A3 1:50,000 For Information 56 157 !( Drawing No. Rev 5 !( !( 159 !( !( !( - 8 A6 Notes !( 351 This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. 317 Clyde House permission of Ordnance Survey on behalf of the Controller of 158 Reform Road Her Majesty's Stationary Office © Crown copyright. !( Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18 389 !( A19 A20 A21

Legend 390 !( Historical Flooding Incidents 387 391 !( !( 392 Council Consultation (2009) !( !( !( Council Recorded (2008 SFRA) 310 !( 386 !( Town and Parish Council (2009) !( !( 388 Flood Defences

357 !( 1963

1968 333 !( 1978 375 !( !(322 1995

2000

2004 365 !( 2005

170 150 2007 3 !( 65 Durham County 73 154 !( 00.511.522.5 63 287 6 103 !( 149 !( !( 153 358 !(!( 99 !( Kilometres 148 !( 59 Client 64 Durham County Council 104 !( Project !( 288 Durham County Strategic Flood Risk Assessment (SFRA) 372 Title Historical Flooding 105 374 373 !( Created by Project Manager Reviewer !( 65 File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev

331 147 A7 - Notes !( !( 334 This map is based upon Ordnance Survey material with the !( © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. 98 Maidenhead Unauthorised reproduction infringes Crown copyright and !( Berkshire 58 SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale 381 - 09514100112 !( Size Status A3 1:50,000 For Information Drawing No. Rev A8 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18 252 !( A19 A20 A21

251 !( 188 !( 190 383 !(!( !( 189 Legend !( 382 Historical Flooding Incidents 254 !( !( Council Consultation (2009) 253 !( !( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009) 25534 !( !( Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A9 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( 260 Council Consultation (2009) 259!( 256 !( !( Council Recorded (2008 SFRA) !( 257 258 !( !( !( Town and Parish Council (2009) 255347 !( !( 180 !( Flood Defences

1963

264 1968 !( 261 1978 !( 262 263 !( !( 1995

2000

2004

2005

2007 302 !( Durham County 00.511.522.5

308 !( Kilometres 186 Client 242 !( 187 !( 266 !( 305 307 !( Durham County Council 185 !( !( !( !( Project !( 265 Durham County Strategic Flood 345 303 Risk Assessment (SFRA) !( Title !( !( Historical Flooding 304 Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date 344 !( Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A10 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 97 96 318 57 !( !( 56 157 !( A1 A2 5 !( !( 159 !( !( !( A3 A4 A5 A6 A7 ¶ 8 !( 351 317 A8A9 A10 A11 A12 A13 158 !( A14 A15A16 A17 A18

A19 A20 A21

100 1 !( 60 !(

Legend 94 !( 54 Historical Flooding Incidents 15 !( Council Consultation (2009) 260 (! !( !( 259!( 321 !( 16 !( Council Recorded (2008 SFRA) 258 !( !( Town and Parish Council (2009) 271 !( Flood Defences 291 !( 1963

290 264 270 335 1968 !( !( !( 289 !( 261 !( 269 272 !( 1978 !( 262 263 !( !( !( 1995 348 !( 268 2000 !( !( 184 2004 341 !( 2005

2007 302 267 !( !( Durham County 00.511.522.5

308 !( 273 Kilometres !( Client 187 !( 266 !( 307 !( !( Durham County Council 65 306 Project 210 Durham County Strategic Flood !( Risk Assessment (SFRA) Title Historical Flooding

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date 209 Scale- 09514100112 !( Size Status A3 1:50,000 For Information Drawing No. Rev 274 !( 277 276 A11 - Notes !( !( This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. 275 181 Maidenhead Unauthorised reproduction infringes Crown copyright and 279 !( Berkshire !( !( SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 318

A1 A2 159 !( !( 331 147 A3 A4 A5 A6 A7 ¶ !( !( 334 317 !( A8A9 A10 A11 A12 A13 158 !( 98 !( A14 A15A16 A17 A18 58 A19 A20 A21

Legend 94 54 !( 17 152 !( !( Historical Flooding Incidents 218 !( !( 15 95 !( Council Consultation (2009) !( !( 55 16 !( Council Recorded (2008 SFRA) 336 !( !( Town and Parish Council (2009) 219 !( Flood Defences 379 !( 2 !(!( 309 1963 !( 380 !( !( 102 1968 !( 62 1978

1995

2000

2004

229 !( 2005 2007

Durham County 00.511.522.5

Kilometres 211 Client !( Durham County Council Project 210 Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date 209 Scale !( - 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A12 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead 398 Unauthorised reproduction infringes Crown copyright and 212 Berkshire !( SL6 8BY may lead to prosecution or civil proceedings. 100049055!( (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents 218 !( !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A13 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 381 !( A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A14 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

!( 244 Legend !( !( Historical Flooding Incidents !( !( Council Consultation (2009) 243 !( !( Council Recorded (2008 SFRA) !( !( Town and Parish Council (2009)

Flood Defences 245 !( 247 1963 !( 248 !( 1968 246 !( 1978

1995

2000

2004

249 2005 !( 2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev

2 A15 - Notes !( This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 !(

A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

364 Historical Flooding Incidents !( 353 !( Council Consultation (2009) 362 363 355 !(!( !( !( !( 354 !( Council Recorded (2008 SFRA) 360 !( 361 359 !( !( !( Town and Parish Council (2009)

Flood Defences 240 !( 1963

239 !( 1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

238 !( Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer 232 !( File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev

217 A16 - Notes !( This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of 221 Reform Road Her Majesty's Stationary Office © Crown copyright. !( Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY 231 +44 (0)1628 586 200 222 09 !(

A1 A2 274 !( 277 276 A3 A4 A5 A6 A7 ¶ !( !( A8A9 A10 A11 A12 A13

181 A14 A15A16 A17 A18 279 275 !( !( !( A19 A20 A21 280 282 !( !( 284 278 !( !(!( 342 !( 283 !( 343

Legend 207 182 !( 241 !( 226 !( Historical Flooding Incidents !( 225 !( 346 !( !( 353 !( 356 220 228 206 !( Council Consultation (2009) 355 !(!( 183 !( !( !( !( 354 227 !( !( Council Recorded (2008 SFRA) 281 !( !( Town and Parish Council (2009)

Flood Defences 240 !( 1963

1968

208 !( 1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status 236 A3 1:50,000 For Information !( Drawing No. Rev A17 - Notes 235 This map is based upon Ordnance Survey material!( with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of 237 Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes!( Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 209 !(

A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

398 A14 A15A16 A17 A18 212 !( !( A19 A20 A21

Legend 7 Historical Flooding Incidents 346 !( Council Consultation (2009)

!( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

1968

208 !( 1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A18 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

A3 A4 A5 A6 A7 ¶

A8A9 A10 A11 A12 A13

A14 A15A16 A17 A18

A19 A20 A21

Legend

Historical Flooding Incidents !( Council Consultation (2009)

!( Council Recorded (2008 SFRA) 23 !( !( Town and Parish Council (2009)

Flood Defences

1963

1968

1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A19 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 A1 A2

217 A3 A4 A5 A6 A7 ¶ !( A8A9 A10 A11 A12 A13 221 !( A14 A15A16 A17 A18

231 A19 A20 A21 222 !( !(!( 223

224 !( 369 Legend !( Historical Flooding Incidents 367 !( !( 368 378 !( !( !( !( 396 397 !( 370 Council Consultation (2009) !( !( 234 395 371 !( !( Council Recorded (2008 SFRA) 230 !( 394 !( Town and Parish Council (2009) !( 393 Flood Defences !( 1963

233 1968 !( 1978

1995 384 !( 2000 385 !( 2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding

Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A20 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 236 !( A1 A2 A3 A4 A5 A6 A7 ¶ 235 !( A8A9 A10 A11 A12 A13 237 !( A14 A15A16 A17 A18

A19 A20 A21

369 !( Legend Historical Flooding Incidents 367 !( !( 368 !( !( !( !( 370 Council Consultation (2009) 234 371 !( Council Recorded (2008 SFRA)

!( Town and Parish Council (2009)

Flood Defences

1963

233 1968 !( 1978

1995

2000

2004

2005

2007

Durham County 00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Historical Flooding Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev A21 - Notes This map is based upon Ordnance Survey material with the © Golder Associates (UK) Ltd. Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire SL6 8BY may lead to prosecution or civil proceedings. 100049055 (2009). +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

OS map not available Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

!( !( !(

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood !( Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer !( !( File No. KD ProjectKD No. 04/02/2010Date !( RE !( Scale !( !( - 09514100112 Size Status !( A3 1:50,000 For Information !( Drawing No. Rev !( M1 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY !( +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

OS map not available Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

!(

00.511.522.5

Kilometres Client !( !(!( Durham County Council !( Project Durham County Strategic Flood Risk Assessment (SFRA) !( Title Surface Water Risk

Created by Project Manager Reviewer !( !( !( File No.RE KD ProjectKD No. 04/02/2010Date !( !( Scale- 09514100112 !( !( !( !( Size Status !( A3 1:50,000 For Information !( Drawing No. Rev !( !( M2 - Notes !( !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of !( Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or !(civil proceedings. 100049055 (2009). SL6 8BY !( +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M3 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood !( Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M4 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY !( +44 (0)1628 586 200 !( !( !( !( !( M1 M2 !( ¶ M3 M4 M5 M6 M7 !( M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18 !( M19 M20 M21

!( !(

!( !( Legend Surface Water Flood Depth (1% (1in 100) event) !( !( !( 0.00 m - 0.10 m !( !( !( !( 0.10 m - 0.25 m !( 0.25 m - 0.50 m !( 0.50 m - 1.00 m !( > 1m !( !(!( !( Historical Flooding Incident !(!( !( !( Indicative Overland Flow Route !( !(!( !( !( !( Durham County

!(

!(

!(

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk !( Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M5 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( !( !( !( !( !( M1 M2 !( !( ¶ M3 M4 M5 M6 M7 !( !( M8M9 M10 M11 M12 M13 !( M14 M15M16 M17 M18 !( !( !( !( M19 M20 M21 !( !( !( !( !( !( !( !( !(!( !( !( !( !( !( !( !( !( Legend !( !( !( Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m !( 0.10 m - 0.25 m !( !(!( 0.25 m - 0.50 m 0.50 m - 1.00 m

!( > 1m

!( Historical Flooding Incident !( !( Indicative Overland Flow Route

!( !( Durham County !( !( !(

!( !( !( !( !( !( !(!(

!( !( (! !( !( !( !( !( !(!( !( 00.511.522.5 !( !(!(!( !(!(!(!( !( !( !(!(!( !( !(!( (! Kilometres !( !( !(!(!( Client !( !( !( !(!( Durham County Council !( !( Project !( !( Durham County Strategic Flood !( !( !( Risk Assessment (SFRA) !(!( !( Title !( !( !( Surface Water Risk !( !( !(!( !( Created by Project Manager Reviewer !( !( !( !( File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status !( !( A3 1:50,000 For Information !( Drawing No. Rev !( !( !( !( !( M6 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. !( Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

!( M19 M20 M21

Legend

!( Surface Water Flood Depth (1% (1in 100) event) !( !( !( 0.00 m - 0.10 m 0.10 m - 0.25 m

!( 0.25 m - 0.50 m !( !( 0.50 m - 1.00 m

> 1m !( !( Historical Flooding Incident

Indicative Overland Flow Route !( Durham County !( !(

!(

!(

!( 00.511.522.5 !( !( !(!( !( !( Kilometres Client Durham County Council !( Project !( Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk !( Created by Project Manager Reviewer !( File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev

!( M7 - Notes !( !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and !( Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 !( Size Status A3 1:50,000 For Information Drawing No. Rev M8 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18 !( M19 M20 M21

!( !( !(!( !( !( Legend

Surface Water Flood Depth (1% (1in 100) event) !( 0.00 m - 0.10 m !( 0.10 m - 0.25 m

0.25 m - 0.50 m !( !( 0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M9 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m !( !( 0.10 m - 0.25 m !( !( !( 0.25 m - 0.50 m !( !( 0.50 m - 1.00 m !( > 1m

!( Historical Flooding Incident !( Indicative Overland Flow Route !( Durham County !( !(

!(

00.511.522.5

!( Kilometres !( !( Client !( !( !( !( Durham County Council !( !( Project !( Durham County Strategic Flood Risk Assessment (SFRA) !( Title !( !( Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date !( Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M10 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( !( (! !( !( M1 M2 !( !( !( ¶ !( M3 M4 M5 M6 M7 M8M9 M10 M11 M12 M13 !( M14 M15M16 M17 M18

M19 M20 M21

!( !(

Legend !( Surface Water Flood Depth (1% (1in 100) event) (! !( 0.00 m - 0.10 m !( !( !( 0.10 m - 0.25 m

!( 0.25 m - 0.50 m

!( 0.50 m - 1.00 m

!( > 1m

!( Historical Flooding Incident !( !( !( !( Indicative Overland Flow Route !( !( !( !( Durham County !( !(

!( !( !(

!(

!( !(

00.511.522.5

!( Kilometres !( !( Client !( !( !( Durham County Council Project Durham County Strategic Flood !( Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 !( Size Status A3 1:50,000 For Information Drawing No. Rev !( !( M11 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and !( !( Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). !( SL6 8BY +44 (0)1628 586 200 M1 M2 !( !( ¶ !( !( M3 M4 M5 M6 M7 !( M8M9 M10 M11 M12 M13 !( !( M14 M15M16 M17 M18 M19 M20 M21

Legend !( !( !( Surface Water Flood Depth (1% (1in 100) event) !( !( 0.00 m - 0.10 m !( !( 0.10 m - 0.25 m !( 0.25 m - 0.50 m

!( 0.50 m - 1.00 m

!(!( !( > 1m !( !( !( !( Historical Flooding Incident !( Indicative Overland Flow Route

Durham County

!(

00.511.522.5

Kilometres Client !( Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale !( - 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M12 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and !( Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY !( +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) !( 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M13 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M14 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

!( !( !( Legend Surface Water Flood Depth (1% (1in 100) event) !( 0.00 m - 0.10 m !( 0.10 m - 0.25 m !( 0.25 m - 0.50 m

0.50 m - 1.00 m

!( > 1m !( !( !( Historical Flooding Incident

!( Indicative Overland Flow Route Durham County

!(

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M15 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

!( Surface Water Flood Depth (1% (1in 100) event) !(!( 0.00 m - 0.10 m !( !( !( 0.10 m - 0.25 m !( !( !( 0.25 m - 0.50 m

0.50 m - 1.00 m

!( > 1m

!( Historical Flooding Incident !( Indicative Overland Flow Route

Durham County

00.511.522.5

!( Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer !( File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M16 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. !( Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !(

M1 M2 !( ¶ !( !( M3 M4 M5 M6 M7 M8M9 M10 M11 M12 M13

!( M14 M15M16 M17 M18 !( !( M19 M20 M21 !( !( !( !(!( !( !(

Legend !( !( !( !( !( Surface Water Flood Depth (1% (1in 100) event) !( !( !( !( !( !( !( 0.00 m - 0.10 m !( !( !( 0.10 m - 0.25 m

!( 0.25 m - 0.50 m

0.50 m - 1.00 m

!( > 1m

!( Historical Flooding Incident

Indicative Overland Flow Route !( Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information !( Drawing No. Rev M17 - Notes !( © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes!( Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18 !( !( M19 M20 M21

Legend ( Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route !( Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date OS map not available Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M18 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ M3 M4 M5 M6 M7

M8M9 M10 M11 M12 M13

M14 M15M16 M17 M18

M19 M20 M21

Legend

Surface Water Flood Depth (1% (1in 100) event) 0.00 m - 0.10 m

0.10 m - 0.25 m !( 0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident

Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M19 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 M1 M2 ¶ !( M3 M4 M5 M6 M7 M8M9 M10 M11 M12 M13 !( M14 M15M16 M17 M18

!( M19 M20 M21 !(!(

!( !( Legend

!( Surface Water Flood Depth (1% (1in 100) event) !(!( !( !( !( 0.00 m - 0.10 m !( !( !( 0.10 m - 0.25 m !( 0.25 m - 0.50 m !( 0.50 m - 1.00 m !( > 1m

!( Historical Flooding Incident !( Indicative Overland Flow Route

Durham County

!(

!(

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M20 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200 !( M1 M2 ¶ M3 M4 M5 M6 M7 !( M8M9 M10 M11 M12 M13

!( M14 M15M16 M17 M18

M19 M20 M21

!( Legend

!( Surface Water Flood Depth (1% (1in 100) event) !(!( !( !( 0.00 m - 0.10 m

0.10 m - 0.25 m

0.25 m - 0.50 m

0.50 m - 1.00 m

> 1m

!( Historical Flooding Incident !( Indicative Overland Flow Route

Durham County

00.511.522.5

Kilometres Client Durham County Council Project Durham County Strategic Flood Risk Assessment (SFRA) Title Surface Water Risk Created by Project Manager Reviewer File No.RE KD ProjectKD No. 04/02/2010Date Scale- 09514100112 Size Status A3 1:50,000 For Information Drawing No. Rev M21 - Notes © Golder Associates (UK) Ltd. This map is based upon Ordnance Survey material with the Clyde House permission of Ordnance Survey on behalf of the Controller of Reform Road Her Majesty's Stationary Office © Crown copyright. Maidenhead Unauthorised reproduction infringes Crown copyright and Berkshire may lead to prosecution or civil proceedings. 100049055 (2009). SL6 8BY +44 (0)1628 586 200