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Nottinghamshire
Level 1 Minerals
SFRA Update
Final Report
July 2015
47071849
UNITED KINGDOM & IRELAND
Prepared for:
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FINAL REPORT
July 2015 47071849
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REVISION SCHEDULE
Rev Date Details Prepared by Reviewed by Approved by
1 January 2015
Draft report for client comment
Ed Byers
Flood Risk Consultant
Penelope Pickerin
Flood Risk Consultant
Jo Somerton
Senior Flood Risk Consultant
Andrew Woodliffe
Associate Director
2 July 2015
Final Report Ed Byers
Flood Risk Consultant
Jo Somerton
Senior Flood Risk Consultant
Carl Pelling
Associate Director
URS Infrastructure and Environment Ltd Royal Court, Basil Close, Chesterfield, S41 7SL, United Kingdom. Phone: +44 (1246) 209221 Fax: +44 (1246) 209229
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Limitations
AECOM and URS have now joined together as one company, and will be known as AECOM moving forward. Whilst the brand is AECOM and operate as one company, contracting entities (all of which are now wholly owned by AECOM) and lines of communication currently remain the same unless specifically agreed or communicated otherwise.
URS Infrastructure & Environment UK Limited (“URS”) has prepared this Report for the sole use of Nottinghamshire County Council (“Client”) in accordance with the Agreement under which our services were performed (Proposal Number: 47065807, dated 21st August 2014). No other warranty, expressed or implied, is made as to the professional advice included in this Report or any other services provided by URS. This Report is confidential and may not be disclosed by the Client nor relied upon by any other party without the prior and express written agreement of URS.
The conclusions and recommendations contained in this Report are based upon information provided by others and upon the assumption that all relevant information has been provided by those parties from whom it has been requested and that such information is accurate. Information obtained by URS has not been independently verified by URS, unless otherwise stated in the Report. The methodology adopted and the sources of information used by URS in providing its services are outlined in this Report. The work described in this Report was undertaken between September 2014 and July 2015 and is based on the conditions encountered and the information available during the said period of time. The scope of this Report and the services are accordingly factually limited by these circumstances.
Where assessments of works or costs identified in this Report are made, such assessments are based upon the information available at the time and where appropriate are subject to further investigations or information which may become available.
URS disclaim any undertaking or obligation to advise any person of any change in any matter affecting the Report, which may come or be brought to URS’ attention after the date of the Report.
Certain statements made in the Report that are not historical facts may constitute estimates, projections or other forward-looking statements and even though they are based on reasonable assumptions as of the date of the Report, such forward-looking statements by their nature involve risks and uncertainties that could cause actual results to differ materially from the results predicted. URS specifically does not guarantee or warrant any estimate or projections contained in this Report.
Copyright
© This Report is the copyright of URS Infrastructure & Environment UK Limited. Any unauthorised reproduction or usage by any person other than the addressee is strictly prohibited.
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TABLE OF CONTENTS 1 INTRODUCTION ............................................................... 1
1.1 Background ...................................................................... 1
1.2 Aims and Objectives........................................................ 2
1.3 SFRA Structure ................................................................ 3 2 STUDY AREA .................................................................... 5
2.1 General overview ............................................................. 5
2.2 Geology ............................................................................. 6
2.3 Current Minerals Extraction Situation ........................... 7
3 POLICY CONTEXT ......................................................... 10
3.2 Flood and Water Management Act ............................... 10 3.3 Amendments to policy on Sustainable Drainage
Systems .......................................................................... 11
3.4 Flood Risk Regulations ................................................. 13
3.5 National Planning Policy ............................................... 14
3.6 Local Planning Policy .................................................... 17 3.7 The Water Framework Directive ................................... 20
4 LEVEL 1 SFRA METHODOLOGY .................................. 21
4.1 Overview ......................................................................... 21
4.2 Tasks ............................................................................... 21
4.3 Stakeholder Consultation ............................................. 21
4.4 Data/Information Requested ......................................... 23 4.5 Data Presentation .......................................................... 25
4.6 GIS Data Review ............................................................. 25
5 FLOOD RISK IN NOTTINGHAMSHIRE .......................... 42
5.1 Introduction .................................................................... 42
5.2 Requirements of the National Planning Policy Framework ...................................................................... 42
5.3 Historical Flooding ........................................................ 42
5.4 Fluvial Flooding ............................................................. 44
5.5 Surface Water Flooding................................................. 52
5.6 Groundwater Flooding .................................................. 53
5.7 Sewer Flooding .............................................................. 53 5.8 Artificial Sources – Canals and Reservoirs ................ 54
5.9 Existing Flood Risk Management in Nottinghamshire57
5.10 Flood Warning Areas ..................................................... 57
5.11 Emergency Planning and Flood Risk .......................... 59
5.12 Potential Future Minerals Sites and Flood Risk ......... 59
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6 FLOOD RISK MANAGEMENT MEASURES .................. 62
6.1 Overview ......................................................................... 62
6.2 Residual Risk ................................................................. 62
6.3 Emergency Planning ..................................................... 63
6.4 Sustainable Flood Risk Management .......................... 63 6.5 Restoration of Minerals Sites ....................................... 64
7 NPPF SEQUENTIAL TEST GUIDANCE......................... 67
7.1 Overview ......................................................................... 67
7.2 Using the SFRA Maps, Data and GIS Layers .............. 71
7.3 How to apply the Sequential Test where there are gaps in data ............................................................................. 73
7.4 The Exception Test ........................................................ 74
7.5 What is a Level 2 SFRA? ............................................... 75
8 SITE SPECIFIC FLOOD RISK ASSESSMENT GUIDANCE ......................................................................................... 76
8.1 Introduction .................................................................... 76
8.2 When is a Flood Risk Assessment required? ............. 76 8.3 Scope of a Site-Specific Flood Risk Assessment ...... 76
8.4 Sequential Approach within Development Sites ........ 79
8.5 Surface Water Management .......................................... 79
8.6 Residual Risk ................................................................. 80
8.7 Summary ......................................................................... 80 9 SUSTAINABLE DRAINAGE SYSTEMS ......................... 82
9.2 What are SuDS? ............................................................. 82
9.3 Why use SuDS? ............................................................. 85
9.4 The SuDS hierarchy ....................................................... 85
9.5 Infiltration SuDS ............................................................. 85
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Table of Tables Table 1-1: NCC Planning Context for the SFRA: Relevant past and future planning documents .................... 2
Table 2-1: Approximate Areas for the Individual LPAs within Nottinghamshire ................................................ 5
Table 4-1: SFRA Mapping Contents ................................................................................................................ 25 Table 4-2: Detailed Modelled Flood Studies provided for use in the SFRA .................................................... 29
Table 4-3: Recommended national precautionary sensitivity ranges for peak rainfall intensity and peak river flow* ................................................................................................................................................................. 30
Table 4-4 Potential Allocation Mineral Extraction Sites ................................................................................... 39
Table 5-1: Flood Risk Areas identified from the Greater Nottingham SFRA for individual Councils............... 51
Table 5-2: Environment Agency Flood Warning Codes .................................................................................. 58 Table 6-1: Potential Allocation Mineral Extraction Sites – Potential Restoration Options ............................... 65
Table 7-1: Flood Risk Vulnerability Classification (PPG, 2014) ...................................................................... 70
Table 7-2: Flood Risk Vulnerability and Flood Zone ‘Compatibility’ (adapted from Planning Practice Guidance, 2014) .............................................................................................................................................. 70
Table 7-3: Sequential Test Key - A Guide to using the SFRA GIS Layers ..................................................... 72
Table 8-1: Site-Specific Flood Risk Assessment Checklist (Planning Practice Guidance) ............................. 77 Table 9-1: Typical SuDS Components ............................................................................................................ 84
Table of Figures Figure 7.1: Application of Sequential Test for Plan-Making ............................................................................ 69
Figure 7.2: Guidance on the application of the Exception Test ....................................................................... 75
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1 INTRODUCTION
1.1 Background
1.1.1 A Level 1 Minerals and Waste Strategic Flood Risk Assessment (SFRA) was produced by
URS/Scott Wilson (now AECOM) for Nottinghamshire County Council (NCC) and Nottingham
City Council (NCiC) in 2011. The SFRA was used as a tool by both parties to support their
emerging Core Strategy, providing information that could be used as part of an evidence base
to support an emerging Joint Waste Development Framework, and by NCC in producing its
Minerals Development Framework.
1.1.2 Since the completion of the initial SFRA in 2011 there have been a number of amendments to
the proposed Mineral Site Allocations as well as the identification of additional sites. Changes
to national planning policy have also occurred since 2011, namely the publication of the
National Planning Policy Framework (NPPF)1 (2012) and accompanying Planning Practice
Guidance (PPG)2 (2014). New and updated flood risk datasets have also been made
available.
1.1.3 These changes must be addressed by a Level 1 SFRA. As such, URS Infrastructure and
Environment UK Ltd (URS) has been commissioned by NCC to produce an updated Level 1
SFRA, with a focus on Minerals Sites.
1.1.4 The updated Level 1 Minerals 1 SFRA represents NCC’s key document assessing flood risk
across the County and will include the following:
• An updated Policy Context which will refer to current national and local mineral and
planning policies;
• Updated methodologies for using the SFRA as a framework for applying the
Sequential Test;
• A review and update of the GIS datasets previously used, for example the updated
SFRA will utilise the Environment Agency’s Updated Flood Maps for Surface Water
(UFMfSW);
• An update of mapping and reporting to include 16 amendments to the 39 sites
reported within the 2011 Level 1 SFRA;
• An update and review of flood risk across Nottinghamshire to account for recent
enhancements in data and understanding following recent flooding events; and,
1 Communities and Local Government (2012) The National Planning Policy Framework https://www.gov.uk/government/publications/national-planning-policy-framework--2 2 Communities and Local Government (2014) National Planning Practice Guidance http://planningguidance.planningportal.gov.uk/
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• An update of appendices to include additional sites and datasets where applicable.
1.2 Aims and Objectives
1.2.1 The aim of this study is to provide an up to date Level 1 SFRA for Nottinghamshire County
which will be used by NCC to inform planning and development policies within the County in
accordance with the NPPF and supporting guidance. The SFRA represents NCC’s primary
document providing a strategic level assessment of flood risk for the County. The report and
accompanying appendices provide an evidence base for flood risk in the County informing the
upcoming Minerals Local Plan and is a key source of information to inform the delivery of
minerals sites within the County.
1.2.2 Table 1-1 provides the planning context for NCC within which the SFRA will sit.
Table 1-1: NCC Planning Context for the SFRA: Relevant past and future planning documents
Planning Document Date of Delivery Context of SFRA
NCC and Nottingham Minerals and Waste Level 1 SFRA April 2011
Minerals Local Plan Issues and Options consultation Jan 2012
Original Minerals and Waste Level 1 SFRA informed consideration of flood risk in Minerals Local Plan
Minerals Local Plan Preferred Approach consultation October 2013
Minerals Local Plan Additional Preferred Approach consultation stages
May 2014 and October 2015
NCC Minerals Level 1 SFRA Update July 2015
Sequential Test To be confirmed
Sequential Test informed primarily by findings of the Minerals Level 1 SFRA Update
Minerals Local Plan Submission Draft consultation September 2015
Flood risk considerations in the Minerals Local Plan informed by the Minerals Level 1 SFRA Update
Submission of Minerals Local Plan December 2015
Examination April 2016
Adoption of Minerals Local Plan June 2016
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1.2.3 The aims of the Level 1 SFRA update will be met through achieving the following objectives:
• To provide an assessment of the impact of all potential sources of flooding in
accordance with NPPF, including an assessment of any future impacts associated with
climate change and sea level rise;
• Enable planning policies to be identified specific to local flooding issues;
• Provide information required to apply the Sequential Test for identification of land
suitable for development in line with the principles of the NPPF;
• To provide baseline data to inform the Sustainability Appraisal of the Development
Plan Documents (DPDs) with regard to catchment-wide flooding issues which affect
the Study Area;
• Provide sufficient information to allow Local Planning Authorities (LPAs) within the
Study Area to assess the flood risk for specific development proposal sites, thereby
setting out the requirements for site specific Flood Risk Assessments (FRAs);
• Provide recommendations of suitable mitigation measures including the objectives of
Sustainable Drainage Systems (SuDS);
• Enable each of the LPAs within the Study Area to use the SFRA as a basis for
decision making at the planning application stage;
• Where necessary, provide technical assessments to demonstrate that development
located in flood risk areas are appropriate and in line with the requirements of the
Exception Test; and,
• Present sufficient information to inform each of the Local Planning Authorities (LPAs)
within the Study Area of acceptable flood risk in relation to emergency planning
capability.
1.3 SFRA Structure
1.3.1 The NCC SFRA report is set out as follows:
• Section 1: Introduction;
• Section 2: Study Area;
• Section 3: Policy Context;
• Section 4: Level 1 SFRA Methodology;
• Section 5: Strategic Assessment of Flood Risk;
• Section 6: Flood Risk Management Measures;
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• Section 7: Sequential Test Guidance;
• Section 8: Site-specific FRA Guidance;
• Section 9: Sustainable Drainage Systems;
• Appendices.
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2 STUDY AREA
2.1 General overview
2.1.1 The study area comprises the administrative area of Nottinghamshire and Nottingham
covering approximately 2,155km2. The study area is illustrated in Appendix A on Figure A-1.
Nottinghamshire is situated within the East Midlands bordering South Yorkshire to the north,
Lincolnshire to the east, Derbyshire to the west and Leicestershire to the south.
Nottinghamshire covers the combined administrative area of the districts/boroughs shown in
Table 2.1.
Table 2-1: Approximate Areas for the Individual LPAs within Nottinghamshire
District / Borough Approximate Area (km2)
Ashfield 109
Bassetlaw 637
Broxtowe 80
Gedling 120
Mansfield 77
Newark and Sherwood 650
Rushcliffe 408
Nottingham City 74
2.1.2 The predominant land uses comprise arable farming and grazing, and urban land use.
Nottingham is the only city within Nottinghamshire. Major towns include Mansfield and
Newark. Other towns include Retford, Worksop, Southwell, Sutton-in-Ashfield, Kirkby-in-
Ashfield, Hucknall, Eastwood, Stapleford, Beeston and West Bridgford.
2.1.3 Nottinghamshire is in the rainfall shadow of the Pennines to the west, so receives relatively
low rainfall at 500–750 mm annually (average over period 1971 - 2000)3.
3 Met Office. Regional Mapped Climate Averages 1971-2000, Annual Rainfall - Midlands. 2011. http://www.metoffice.gov.uk/climate/uk/averages/regmapavge.html#midlands
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2.2 Geology
2.2.1 Clays, sandstone and limestone form the predominant solid bedrock types within
Nottinghamshire. Unconsolidated superficial deposits mainly consist of sands and gravel,
alluvium and glacial till. Contained within the solid and unconsolidated material is a mix of
mineral resources, which have enabled the County to become one of the largest mineral
producers in Great Britain.
2.2.2 The exposed bedrocks range from Upper Carboniferous to Lower Jurassic in age. The main
structural trend is a shallow east-south-east dip which means the oldest rocks are found in the
west with the overlying younger rocks being progressively exposed to the east.
2.2.3 Upper Carboniferous Coal Measures (mudstones, coals and sandstones) occur on the
western border of Nottinghamshire. The overlying Permian age Magnesian Limestone forms a
shallow escarpment running north from Nottingham through Mansfield and intermittently up to
Oldcotes4.
2.2.4 Triassic sandstones of the Sherwood Sandstone Group outcrop through central and eastern
Nottinghamshire. The porous nature of the Sherwood Sandstone gives rise to free-draining
soils in this outcrop area, which includes Sherwood Forest. Much of the central and eastern
part of Nottinghamshire is dominated by mudstones of the Triassic Mercia Mudstone Group.
This is marked by an escarpment along the boundary with the Sherwood Sandstone which to
the east gives rise to the relatively flat, undulating landscape through which the River Trent
has cut its wide floodplain4. Between Nottingham and Newark-on-Trent there is a very distinct
trench. This is believed to have been created during the ice ages when the river’s route to the
Wash via the Ancaster Gap was blocked by ice in the Vale of Belvoir forcing it northwards.
2.2.5 The eastern border of Nottinghamshire is marked by a change to the thick blue clays (Lias) of
the Lower Jurassic age. Areas of open water along the course of the River Trent represent
former workings for gravel, huge quantities of which were deposited by the meandering nature
of the river over the past 15,000 years4. In the far south of Nottinghamshire a thick blanket of
boulder clay forms an undulating landscape known as the ‘Wolds’
4 Natural England. (2011) Nottinghamshire (including City of Nottingham). http://www.naturalengland.org.uk/ourwork/conservation/geodiversity/englands/counties/area_ID26.aspx
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2.3 Current Minerals Extraction Situation
2.3.1 According to the NCC Minerals Local Plan Preferred Approach Consultation Document
(2013)5, Nottinghamshire (excluding Nottingham City in this case) is rich in mineral resources
which serve both local and wider needs. Nottinghamshire is the largest producer of sand and
gravel in the East Midlands and one of the largest in Great Britain. Sand and gravel is worked
from alluvial material found in the Trent and Idle Valleys, with Sherwood Sandstone also
extracted. Gypsum is also identified as a major mineral for extraction within Nottinghamshire.
Although less significant with regards to volume, brick clay, silica sand, building stone,
aggregate limestone and oil are also extracted within Nottinghamshire. Dolomite, located in
the north, and potential shale gas in the north and south of Nottinghamshire are also identified
as mineral resources which may potentially be exploited in the future.
Sand and Gravel
2.3.2 Nottinghamshire’s sand and gravel production has generally mirrored national trends with
production peaking at 3.6 million tonnes in 1988; however production trends began to fall to an
average of 2.7 million tonnes between 1997 and 2001. This trend is believed to reflect a
decline in construction/road activity, a greater use of secondary aggregates and a long-term
national trend that has shifted from sand and gravel to crushed rock. Between 2008 and 2012
annual production has dropped to below 1.75 million tonnes, with a low point of 1.27 million
tonnes in 2009. The drop in production was attributed to the recession and the temporary
relocation of production at Finningley Quarry across the County boundary to Doncaster6. The
latest figure of 1.55 million tonnes was given for 20127.
2.3.3 In 2009 approximately half of the sand and gravel (in addition to Sherwood Sandstone)
produced in Nottinghamshire was used within the County, with 22% exported in the East
Midlands, and the remainder exported elsewhere, particularly Yorkshire and Humberside.
2.3.4 The Local Aggregates Assessment6 identifies that output from the Idle Valley is starting to be
limited by depletion in sand and gravel resources, with capacity decreasing by approximately
half from 1.5 million tonnes in the period of 2003 to 2011.
2.3.5 The Trent Valley will therefore be required to meet nearly all of the requirements in the
medium to long term. Finding sufficient environmentally acceptable sites to continue
production at current levels much beyond the plan period, as other sites close, is likely to be a
fundamental issue for the future. This can only reinforce the need for significant long-term
reductions in dependence on sand and gravel for meeting demand for aggregates.
5 Nottinghamshire County Council (2013) Nottinghamshire Minerals Local Plan Preferred Approach Consultation Document 6 Nottinghamshire County Council (2013) Nottinghamshire Minerals Local Plan – Local Aggregate Assessment 7 Nottinghamshire County Council (2014) Nottinghamshire Minerals Local Plan – Local Aggregate Assessment Update
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Sherwood Sandstone
2.3.6 In Nottinghamshire extraction of Sherwood Sandstone (covering nearly a quarter of the
County) reached a peak of 1.15 million tonnes in 1992; however production reached lows of
0.32 million tonnes in 2009 and 2010, with limited increases in the subsequent two years. The
latest reported 10-year average is 0.44 million tonnes per year7. The Local Aggregates
Assessment identifies production of this resource as historically being in steady decline.
2.3.7 The Local Plan Preferred Approach Consultation Document5 identifies the Sherwood
Sandstone as a major aquifer and important source of water for an extensive area.
Limestone
2.3.8 Limestone is the only ‘hard rock’ of any economic interest to be found in Nottinghamshire, and
Nottinghamshire’s output is very low compared to the regional production which is large.
Today production of aggregate limestone is limited to one quarry immediately south-east of
Nether Langwith. Small quantities of building stone are also produced at a quarry near Linby.
This works a local variation of the Magnesian Limestone known as the Bulwell Stone.
2.3.9 Whilst the 10-year average is 0.06 million tonnes, no production was recorded between 2009
and 2012.
Brick Clay
2.3.10 Prior to the recent recession in Britain, Nottinghamshire’s production of brick clay was
estimated to be around 350,000 to 400,000 tonnes per annum. The Minerals Local Plan Brick
Clay Background Paper8 states that only the Mercia Mudstone formation has been exploited
for Brick Clay since the late 1970’s. This is extracted at brick pits at Dorket Head near Arnold
and Kirton which support associated modern brickworks that manufacture high quality facing
bricks. Together these make a significant contribution towards regional brick production.
2.3.11 There is no national demand forecast for clay but it is reasonable to assume that demand will
remain broadly similar to recent levels.
Gypsum
2.3.12 Nottinghamshire is one of the UK’s largest gypsum producing areas. High quality mineral is
extracted from a quarry at Balderton near Newark, with mill and cement grade mineral won
from a drift mine at East Leake. These supply associated plasterboard and plaster works.
Reserves of both resources are believed to be high.
8 Nottinghamshire County Council (January 2012) Nottinghamshire Minerals Local Plan Background Paper: Brick Clay
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Coal
2.3.13 The exposed coalfield in the Erewash Valley has been worked extensively, mined by opencast
methods but no opencast coal mining has occurred since 19999. Significant resources are
known to remain and proposals to exploit this mineral in the future may occur especially if
energy prices remain high. Nottinghamshire’s ‘deep mined’ coal industry has collapsed over
the last 30 years, falling from 29 collieries in 1980 to just one active colliery at Thorseby today.
Another colliery (Harworth) is currently mothballed. Most former collieries including the
associated spoil heaps have been reclaimed although some tips have and are being washed
to recover coal.
2.3.14 A surface coal mine was granted planning permission, subject to the signing of a legal
agreement, in 2013 at Shortwood Farm towards the west of the County.
Hydrocarbons – Oil and Gas
2.3.15 Nottinghamshire has been producing oil on a small scale since the Second World War. Today
there are nine active fields10. The Local Plan Preferred Approach Consultation Document
states that major increases in oil production are unlikely to occur in the near future. In 2010
planning permission was given to explore for coal bed methane in four locations but no drilling
has yet commenced. Mine gas, which represents a separate source to coal bed methane,
exploits the build-up of methane gas which occurs following cessation of mine ventilation as a
result of closure of a mine. The Hydrocarbons Background Paper10 indicates that in 2010 there
were eleven mine gas schemes, with a further four proposed.
Other Minerals
2.3.16 Silica sand is a non-aggregate form of Sherwood Sandstone5 and prices for such minerals are
higher than aggregate sands. The mineral has been extracted within Nottinghamshire for the
past 150 years. From 1999 Ratcher Hill Quarry east of Mansfield was the sole source of silica
sand within Nottinghamshire and currently produces approximately 200,000 to 250,000 tonnes
per annum.
2.3.17 Industrial Dolomite is predominantly utilised in the iron and steel industry, however no
industrial dolomite is currently extracted within Nottinghamshire.
2.3.18 Building stone is identified in the Local Plan Preferred Approach Consultation Document as
important for the purposes of repair of historic buildings and the development of new buildings
in historic areas. The only building stone currently extracted is Bulwell Stone.
9 Nottinghamshire County Council (January 2012) Nottinghamshire Minerals Local Plan Background Paper: Coal 10 Nottinghamshire County Council (January 2012) Nottinghamshire Minerals Local Plan Background Paper: Hydrocarbons
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3 POLICY CONTEXT
3.1.1 Since the 2011 SFRA was completed, updates to national and local planning policy and flood
risk have been implemented. This section provides an updated summary of policy relevant to
the SFRA.
3.2 Flood and Water Management Act
3.2.1 In response to the severe flooding across large parts of England and Wales in summer 2007,
the Government commissioned Sir Michael Pitt to undertake a review of flood risk
management. The Pitt Review – Learning Lessons from the 2007 Floods11 and subsequent
progress reviews outlined the need for changes in the way the UK is adapting to the increased
risk of flooding and the role different organisations have to deliver this function.
3.2.2 The Flood and Water Management Act 2010 (FWMA)12, enacted by Government in response
to The Pitt Review, designated unitary authorities, including NCC, as Lead Local Flood
Authorities (LLFAs). As LLFA for Nottinghamshire, NCC has responsibilities to lead and co-
ordinate local flood risk management. Local flood risk is defined as the risk of flooding from
surface water runoff, groundwater and small ditches and watercourses (collectively known as
ordinary watercourses).
3.2.3 The FWMA formalises the flood risk management roles and responsibilities for other
organisations including the Environment Agency, water companies and highways authorities.
The responsibility to lead and co-ordinate the management of tidal and (main river) fluvial
flood risk remains that of the Environment Agency.
3.2.4 The FWMA initially gave LLFAs the role of Sustainable Drainage Systems Approval Body
(SAB) where the LLFA is responsible for adopting and maintaining SuDS. However, as
detailed below, the use of SuDS in new development will now be enforced by LPAs through
the planning system, and not through the LLFA SABs.
11 Cabinet Office (2008) Sir Michael Pitt Report ‘Learning lessons learned from the 2007 floods’ http://www.environment-agency.gov.uk/research/library/publications/33889.aspx 12 HMSO (2010) The Flood and Water Management Act 2010 http://www.legislation.gov.uk/ukpga/2010/29/contents
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3.3 Amendments to policy on Sustainable Drainage Systems
3.3.1 Following a consultation by Defra on the delivery of SuDS13 in 2014 the Department for
Communities and Local Government (DCLG) issued a Written Statement14 outlining the
Government’s response regarding the future of SuDS. This was followed by a consultation
exercise carried out in December 201415 by DCLG on the proposal to make LLFAs statutory
consultees for planning applications with regards to surface water management, and the
Government published its formal response in March 201516. The PPG has subsequently been
amended to reflect the new approach to implementation of SuDS in development.
3.3.2 The proposed approach is to strengthen the planning system as a way of delivering SuDS,
rather than implement Schedule 3 of the FWMA, as written, which would establish a new SAB
that would sit outside the existing planning system. This will be achieved principally by
amending planning policy so that LPAs can give increased weight to the provision and
maintenance of SuDS, alongside other material considerations, during the determination of a
planning application.
3.3.3 From 6 April 2015 LPAs, including those within NCC, will be expected to ensure that local
planning policies and decisions on planning applications relating to major development include
SuDS for the management of run-off, unless demonstrated to be inappropriate. Minor
developments with drainage implications would continue to be subject to existing planning
policy (Section 103 of the NPPF) and smaller developments in flood risk areas should still give
priority to the use of SuDS.
3.3.4 The PPG has been amended to state:
3.3.5 “Sustainable drainage systems may not be practicable for some forms of development (for
example, mineral extraction). New development should only be considered appropriate in
areas at risk of flooding if priority has been given to the use of sustainable drainage systems.
Additionally, and more widely, when considering major development, sustainable drainage
systems should be provided unless demonstrated to be inappropriate.”
3.3.6 LPAs within Nottinghamshire should consult NCC, as LLFA, on the management of surface
water for major development. NCC, as the LLFA, is a statutory consultee for planning
applications for major developments that have a drainage implication. As a statutory
consultee, NCC will be under a duty to respond to the LPA and report on their performance on
providing a substantive response within deadlines set out in legislation. 13 Defra / DCLG (September 2014) Delivering Sustainable Drainage Systems: Consultation 14 Department for Communities and Local Government (December 2014) House of Commons Written Statement (HCWS161) Sustainable Drainage Systems 15 DCLG (December 2014) Consultation on Further changes to statutory consultee arrangements for the planning application process 16 DCLG (March 2015) Further changes to statutory consultee arrangements for the planning application process: Government response to consultation.
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LPAs will be required to
• Satisfy themselves that the proposed minimum standards of operation are appropriate,
and;
• Ensure, through the use of planning conditions or planning obligations, that there are
clear arrangements in place for ongoing maintenance over the lifetime of the
development.
3.3.7 “Local planning authorities are also advised to consult as appropriate:
• The relevant sewerage undertaker where a connection with a public sewer is
proposed;
• The Environment Agency, if the drainage system directly or indirectly involves the
discharge of water into a watercourse;
• The relevant highway authority for an affected road;
• The Canal and Rivers Trust, if the drainage system may directly or indirectly involve
the discharge of water into or under a waterway managed by them;
• An Internal Drainage Board, if the drainage system may directly or indirectly involve
the discharge of water into an ordinary watercourse (within the meaning of section 72
of the Land Drainage Act 1991) within the board's district.”
3.3.8 “The decision on whether a sustainable drainage system would be inappropriate in relation to
a particular development proposal is a matter of judgement for the local planning authority. In
making this judgement the local planning authority will seek advice from the relevant flood risk
management bodies, principally the lead local flood authority.”
National Strategy for Flood and Coastal Erosion Risk Management
3.3.9 In accordance with the FWMA, the Environment Agency has developed a National Strategy for
Flood and Coastal Erosion Risk Management (FCERM) in England17. This Strategy provides a
framework for the work of all flood and coastal erosion risk management authorities.
3.3.10 The National FCERM Strategy sets out the long-term objectives for managing flood and
coastal erosion risks and the measures proposed to achieve them. It sets the context for, and
informs the production of, Local Flood Risk Management Strategies (LFRMS) by LLFAs, which
will in turn provide the framework to deliver local improvements needed to help communities
manage local flood risk. It also aims to encourage more effective risk management by
enabling people, communities, business and the public sector to work together to:
17 Defra, Environment Agency (2011) The National Flood and Coastal Erosion Risk Management Strategy for England.
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• Ensure a clear understanding of the risks of flooding and coastal erosion, nationally
and locally, so that investment in risk management can be prioritised more effectively;
• Set out clear and consistent plans for risk management so that communities and
businesses can make informed decisions about the management of the remaining
risks;
• Encourage innovative management of risks taking account of the needs of
communities and the environment; and,
• Ensure that emergency responses to flood incidents are effective and that
communities are able to respond properly to flood warnings.
3.3.11 The Environment Agency’s ‘Adapting to Climate Change: Advice for Flood and Coastal
Erosion Risk Management Authorities’18 guidance is a supporting note for the National
FCERM Strategy. It provides the UK Climate Projections (UKCP09)19 climate change factors
for river flood flows and extreme rainfall for each river basin district, and provides advice on
applying climate change projections in the FCERM. It is essential that land use planning
decisions consider the impact of a changing climate where appropriate.
Local Flood Risk Management Strategy
3.3.12 As a LLFA, NCC has a statutory duty to develop, maintain, apply and monitor a strategy for
local flood risk management. NCC is currently in the process of preparing their LFRMS and
should use this Level 1 SFRA update as a vital source of baseline information.
3.4 Flood Risk Regulations
3.4.1 As well as the duties under the FWMA to prepare a LFRMS, NCC has legal obligations, under
the EU Floods Directive20, which was transposed into UK Law through the Flood Risk
Regulations 200921 (‘the Regulations’). LLFAs must prepare FRMPs for formally identified
Flood Risk Areas where the risk of flooding from local sources is significant (i.e. surface water,
groundwater, ordinary watercourses), and the Environment Agency is required to prepare
FRMPs for all of England covering flooding from Main Rivers, the sea and reservoirs.
18 Environment Agency (2010) Adapting to Climate Change: Advice for Flood and Coastal Erosion Risk Management Authorities 19 The Met Office (2015) UKCP09 climate projections http://ukclimateprojections.metoffice.gov.uk/ 20 European Union (2007) EU Floods Directive http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32007L0060:EN:NOT 21 HSMO (2009) The Flood Risk Regulations http://www.legislation.gov.uk/uksi/2009/3042/contents/made
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Preliminary Flood Risk Assessment
3.4.2 Under the Regulations, all LLFAs were required to prepare a PFRA report. This is a high level
screening exercise to identify areas of significant risk as Indicative Flood Risk Areas across
England where 30,000 people or more are at risk from flooding for reporting to Europe. NCC
delivered its PFRA22 in 2011. The PFRA seeks to provide a high level overview of flood risk
from local flood sources and includes flooding from surface water (i.e. rainfall resulting in
overland runoff), groundwater, ordinary watercourses (smaller watercourses and ditches) and
canals. It excludes flood risk from main rivers, the sea and reservoirs as these are assessed
nationally by the Environment Agency.
3.4.3 The PFRA report looks at past flooding and where future flooding might occur across the area
and the consequences it might have to people, properties and the environment. Analysis in the
PFRA indicates that Nottingham could be considered as a Flood Risk Area, however the
report recommended that Nottingham should be considered jointly in the NCC and NCiC
LFRMS. The report also concluded that it is not necessary for NCC to prepare a FRMP.
Humber River Basin District draft Flood Risk Management Plan
3.4.4 The EU Floods Directive, transposed into UK Law through the Flood Risk Regulations,
requires the Environment Agency prepare FRMPs for all of England covering flooding from
Main Rivers, the sea and reservoirs.
3.4.5 As such, the Humber River Basin District FRMP23 has been published for consultation by the
Environment Agency and sets out the proposed measures to manage flood risk in the Humber
River Basin District from 2015 to 2021 and beyond. This document draws on existing reports
and plans which have been prepared in the past.
3.5 National Planning Policy
National Planning Policy Framework
3.5.1 The NPPF was published on 27th March 2012 together with accompanying Technical
Guidance24. The NPPF revoked most of the previous Planning Policy Statements (PPS) and
Planning Policy Guidance, including PPS25: Development and Flood Risk Practice Guide25.
However, NPPF did not revoke the PPS25 Practice Guide. This was revoked on the
6th March 2014 along with the NPPF Technical Guidance, when it was replaced by the PPG.
22 JBA Consulting (June 2011) Nottinghamshire County Council Preliminary Flood Risk Assessment. http://www.nottinghamshire.gov.uk/enjoying/countryside/flooding/lead-local-flood-authority/pfra/ 23 Environment Agency (October 2014) Humber River Basin District Consultation on the draft Flood Risk Management Plan https://consult.environment-agency.gov.uk/portal/ho/flood/draft_frmp/consult?pointId=s1407245182324#section-s1407245182324 24 Communities and Local Government. (March 2012) Technical Guidance to the National Planning Policy Framework 25 Department for Communities and Local Government. (2009) Planning Policy Statement 25: Development and Flood Risk Practice Guide
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3.5.2 The NPPF consists of a framework within which LPAs and local people can produce local and
neighbourhood plans that reflect the needs and priorities of their communities.
3.5.3 The overall approach to flood risk is broadly summarised in NPPF Paragraph 103:
3.5.4 “When determining planning applications, local planning authorities should ensure flood risk is
not increased elsewhere and only consider development appropriate in areas at risk of
flooding where, informed by a site-specific FRA following the Sequential Test, and if required
the Exception Test, it can be demonstrated that:
• Within the site, the most vulnerable development is located in areas of lowest flood
risk unless there are overriding reasons to prefer a different location, and
• Development is appropriately flood resilient and resistant, including safe access and
escape routes where required, and that any residual risk can be safely managed,
including by emergency planning; and it gives priority to the use of sustainable
drainage systems.”
3.5.5 The NPPF and supporting guidance require LPAs to undertake SFRAs and to use their
findings, and those of other studies, to inform strategic land use planning, including the
application of the Sequential Test which seeks to steer development towards areas of lowest
flood risk prior to consideration of areas of greater risk.
3.5.6 The PPG states that:
3.5.7 “County level assessments may also be appropriate where minerals and waste issues can be
considered at the same time.”
3.5.8 As the Minerals Planning Authority (MPA) for Nottinghamshire, it is therefore appropriate for
NCC to deliver the Level 1 Minerals SFRA.
3.5.9 In preparing its Minerals Local Plan NCC should:
3.5.10 “set out environmental criteria, in line with the policies in [the NPPF], against which planning
applications will be assessed so as to ensure that permitted operations do not have
unacceptable adverse impacts on the natural and historic environment or human health,
including from… flood risk, impacts on the flow and quantity of surface and groundwater and
migration of contamination from the site; and take into account the cumulative effects of
multiple impacts from individual sites and/or a number of sites in a locality.”
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National Planning Practice Guidance
3.5.11 The NPPF is supported by a series of Planning Practice Documents referred to as the PPG.
The PPG: Flood Risk and Coastal Change document outlines how LPAs, or MPAs, should use
the SFRA, as follows:
• SFRAs should assess the flood risk to an area from all sources, both in the present
day, and in the future. The impacts of climate change should be considered when
assessing future flood risk;
• The impact on flood risk of future development and changes to land use should also
be considered;
• The SFRA should provide the foundation from which to apply the Sequential Test and
Exception Test in the development allocation and development control process. Where
decision-makers have been unable to allocate all proposed development and
infrastructure in accordance with the Sequential Test, taking account of the flood
vulnerability category of the intended use, it will be necessary to increase the scope of
the SFRA (Level 2 SFRA) to provide the information necessary for application of the
Exception Test;
• The SFRA should inform the sustainability appraisal of the Local Plan;
• The SFRA should outline requirements for site-specific FRAs, with specific
requirements for particular locations;
• The SFRA should define the flood risk in relation to emergency planning’s capacity to
manage flooding;
• Opportunities to decrease the existing flood risk within the study areas should be
explored, such as surface water management, provision of flood storage and
managing conveyance of flood flows.
3.5.12 SFRAs should be prepared in consultation with the Environment Agency, emergency
response and drainage authority functions of LPAs, LLFAs and where appropriate Internal
Drainage Boards (IDBs).
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3.5.13 With regards to development of Minerals and Waste Local Plans, the PPG states that:
3.5.14 “Waste and mineral planning authorities need to take account of flood risk when allocating
land for development. They should prepare their plan policies with regard to any available
Strategic Flood Risk Assessments. The location of Mineral Safeguarding Areas and site
allocations, in particular in relation to sand and gravel workings which are often located in
functional floodplains, need to be identified. It is possible to explore benefits, such as restoring
mineral working located in flood risk areas to increase flood water storage, which can also
enhance the natural environment.”
Minerals and Waste Policy
3.5.15 The majority of Minerals Planning Guidance (MPG) Notes and Minerals Policy Statements
were cancelled with the publication of the NPPF. The following documents remain in force until
they are cancelled or replaced:
• National and Regional guidelines for aggregates provision in England 2005-2020;
• Letter to Chief Planning Officers: National and regional guidelines for aggregates
provision in England - 2005-2020.
3.5.16 To assist Mineral Planning Authorities (MPAs) and Waste Planning Authorities (WPAs) in their
strategic land use planning, SFRAs should present sufficient information to enable them to
apply the sequential approach where possible to the allocation of sites. It is acknowledged
within the NPPF that minerals have to be extracted and processed where the minerals are
located but that the operational workings "should not increase flood risk elsewhere and need
to be designed, worked and restored accordingly”.
3.6 Local Planning Policy
Nottinghamshire Minerals Local Plan Preferred Approach Consultation Document
3.6.1 In 2013 consultation on the New Minerals Local Plan took place. Once adopted, the Plan will
form the land use planning strategy for mineral development within Nottinghamshire. The plan
will provide a basis for the determination of mineral planning applications within
Nottinghamshire with the overarching aim of promoting sustainable development and
achieving high quality restoration where possible. It is envisaged that long term environmental
gains can be actualised through the creation of wildlife habitats for instance whilst facilitating
the safeguarding of mineral resources for future generations.
3.6.2 The plan will provide a long term vision for mineral development in Nottinghamshire,
supported by strategic objectives to deliver this aim up to a plan period of 2030.
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3.6.3 Strategic policies relevant to flood risk and the water environment in Nottinghamshire are
summarised below.
3.6.4 Policy SP2 – Biodiversity-Led Restoration: Where appropriate, schemes will be expected
to demonstrate how restoration will contribute to the delivery of the Water Framework Directive
(WFD) targets.
3.6.5 Policy SP3 – Climate Change: All minerals development, including site preparation,
operational practices and restoration proposals should minimise their impact on the causes of
climate change for the lifetime of the development. Where applicable development should
assist in the reduction of vulnerability and provide resilience to the impacts of climate change
by:
a) Being located, designed and operated to help reduce greenhouse gas emissions and move towards a low-carbon economy;
b) Avoiding areas of vulnerability to climate change and flood risk. Where avoidance is not possible, impacts should be fully mitigated;
c) Developing restoration schemes which will contribute to addressing future climate change adaptation.
3.6.6 Policy DM2 – Water Resources and Flood Risk: Water Resources
1. Proposals for minerals development will be supported where it can be demonstrated that:
a) Surface water flows at or in the vicinity of the site are not detrimentally altered;
b) Groundwater quality and levels, where critical, are not altered;
c) There are no risks of polluting ground or surface waters;
d) Water resources, where required, should be used as efficiently as possible.
3.6.7 Policy DM2 – Water Resources and Flood Risk: Flooding
2. Proposals for minerals development will be supported where it can be demonstrated there will be no unacceptable impact on:
a) Flood flows and storage capacity;
b) The integrity or function of flood defences or structures acting as flood defences;
c) Local land drainage systems;
d) Local communities.
3. Where the opportunity exists, restoration proposals should seek to incorporate flood risk reduction measures e.g. floodplain storage, flood defence structures, land management, land practices etc. to benefit local communities.
4. Proposals for mineral extraction that increase flood risk to local communities must be fully mitigated.
5. Proposals for minerals development should consider the potential for flood storage
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schemes to be incorporated into restoration proposals to reduce future flooding issues.
6. Minerals development should include SuDS to manage surface water drainage.
3.6.8 Policy DM4 – Protection and Enhancement of Biodiversity and Geodiversity:
1. Proposals for minerals development will be supported where it can be demonstrated that:
a) There will be no significant adverse impacts on habitats or species or, where impacts cannot be avoided, adequate mitigation and/or compensation relative to the importance of the resource can be put in place; and
b) They will not give rise to any significant effects on the integrity of a European site, either alone or in combination with other plans or projects, as a result of changes to water quality [and] hydrology.
Nottinghamshire Minerals Local Plan
3.6.9 The Nottinghamshire Minerals Local Plan26 was adopted in December 2005 replacing the
previous Minerals Local Plan27 adopted in 1997 and has a plan period which extends up to
2014. The Minerals Local Plan provides a detailed set of minerals policies which can be used
to test the acceptability of all minerals planning proposals within Nottinghamshire.
3.6.10 The current Minerals Local Plan will be replaced by the new Minerals Local Plan which will
contain all policies and site-specific allocations for the County. Until the new Minerals Local
Plan is adopted, most of the current Minerals Local Plan policies have been saved by the
Secretary of State. Those which are relevant to flood risk and the water environment in
Nottinghamshire are summarised below.
3.6.11 Policy M3.9 ‘Flooding’ states that planning permission for minerals development will not be
granted where there is an unacceptable impact on flood flows and flood storage capacity or on
the integrity or function of flood defences and local land drainage systems unless conditions
can be imposed to protect flood defences from both the temporary and permanent adverse
effects of the development;
3.6.12 Policy M3.8 ‘Water Environment’ states that planning permission for minerals development
will only be granted where (a) surface water flows are not detrimentally altered; (b)
groundwater levels, where critical, are not affected; and (c) there are no risks of polluting
ground or surface waters. Unless engineering measures and/ or operational management
systems can adequately mitigate such risks; and
26 Nottinghamshire County Council (2005) Nottinghamshire County Council Adopted Minerals Local Plan 27 Nottinghamshire County Council (1997) Nottinghamshire County Council Minerals Local Plan (superseded)
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3.6.13 Policy M9.1 ‘Stockpiling of Dredgings’ - Proposals for the stockpiling of river dredgings prior
to their use as aggregate will be permitted subject to measures to protect the integrity of the
floodplain.
3.7 The Water Framework Directive
3.7.1 The EU Water Framework Directive (WFD) (2000/60/EC)28 establishes a framework for the
protection and improvement of inland surface waters (rivers and lakes), transitional waters
(estuaries), coastal waters and groundwater.
3.7.2 The Directive requires the UK to classify the current condition of key waterbodies (giving a
‘Status’ or ‘Potential’) and set objectives to either maintain their condition, or improve it where
a waterbody is failing minimum targets. The chemical quality status obtainable by a
watercourse is either ‘Good’ or ‘Fail’ and the ecological quality status obtainable ranges from
‘High’ to ‘Bad’. The target for all watercourses should be to achieve at least ‘Good’ chemical
and ecological status. Any activities or developments that could cause deterioration within a
nearby waterbody, or prevent the future ability of a waterbody to reach its target Status, must
be mitigated so as to reduce the potential for harm and allow the aims of the WFD to be
realised.
3.7.3 As well as ensuring that development does not result in deterioration in the Status of a
waterbody, development can contribute towards attainment of WFD objectives, as well as
other environmental benefits. Restoration of minerals sites may provide such opportunities
within Nottinghamshire.
28 Commission of the European Communities (2000) Directive 2000/60/EC 'The Water Framework Directive'
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4 LEVEL 1 SFRA METHODOLOGY
4.1 Overview
4.1.1 As outlined in Section 1, one of the objectives of the Level 1 SFRA update is to collect, collate
and review available information relating to flooding in the Study Area. The information is then
presented in a format to enable NCC to apply the NPPF Sequential Test to their preferred
sites for future development and to identify potential development sites which require the
application of the Exception Test through a Level 2 SFRA.
4.2 Tasks
4.2.1 The sequence of tasks undertaken in Stage 1 of the preparation of the Level 1 SFRA was, in
chronological order:
• Establish the local Stakeholders;
• Contact Stakeholders requesting data/information;
• Collate and review data and populate data register;
• Presentation of available relevant information on flood sources and flood risk;
• Review received data against the SFRA objectives; and
• Identify gaps in data.
4.2.2 The above tasks were completed between September 2014 and December 2014.
4.3 Stakeholder Consultation
4.3.1 In the preparation of this Level 1 SFRA update, the following stakeholders were contacted to
provide data and information:
• Nottinghamshire County Council;
• Environment Agency;
• Severn Trent Water;
• Anglian Water Services;
• Isle of Axholme and North Nottinghamshire Water Level Management Board
(IOANNWLMB);
• Trent Valley Internal Drainage Board;
• Doncaster East Internal Drainage Board;
• Highways Agency; and,
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• Canal and Rivers Trust.
4.3.2 The Study Area falls within the Environment Agency’s Derbyshire, Nottinghamshire and
Leicestershire Area of responsibility. The Environment Agency has discretionary powers under
the Water Resources Act (1991)29 for all Main Rivers and their associated flood defences
within the Study Area.
4.3.3 NCC, as the LLFA for Nottinghamshire, is responsible under the FWMA for managing flood
risk from local sources; groundwater, surface water and ordinary watercourses.
4.3.4 Severn Trent Water (STW) is the statutory water supply and sewerage provider for the
majority of the Study Area. However, Anglian Water (AWS) provide potable water distribution
for a small area along the north eastern boundary of the Study Area.
4.3.5 AWS confirmed that they held no records of sewer flooding within the Study Area.
4.3.6 STW provided records of surface, foul and combined (surface and foul) sewer flooding
incidents within Nottinghamshire.
4.3.7 The Canal and Rivers Trust (C&RT) is responsible for maintaining the inland navigable
waterway network across the UK including the Nottingham, Erewash, Beeston, Grantham and
Chesterfield canals located in the Study Area.
4.3.8 Nottinghamshire's administrative area includes watercourses that are administered by various
IDBs. IDBs are statutory bodies under the Land Drainage Act 1991. Trent Valley IDB,
Doncaster East IDB and Upper Witham IDB were all contacted for information, as well as the
IOANNWLMB. Upper Witham IDB covers only small sections of the very east of
Nottinghamshire. All four Boards were given an opportunity to provide comment on the draft
Minerals Level 1 SFRA Update and their responses are outlined below.
4.3.9 The IOANNWLMB and Trent Valley IDB both stated a commitment to participate at an early
stage should any relevant potential mineral sites be brought forward for development. Both
Boards highlighted that some potential mineral sites may have an impact on the drainage
network and therefore should be included in discussions relating to development of such sites.
4.3.10 The IOANNWLMB identified the following sites as being located within the Board’s district, and
may have Board maintained watercourses within or in close proximity to the site:
• PA01, PA02, PA06
29 HMSO (1991) The Water Resources Act
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4.3.11 The IOANNWLMB also identified the following sites as being outside the Board’s district,
though within the Board’s catchment:
• PA31, PA32, PA33
4.3.12 The Trent Valley IDB identified the following sites as being located within the Board’s district,
and may have Board maintained watercourses within or in close proximity to the site:
• PA03, PA04, PA07, PA08, PA10, PA11, PA14, PA16, PA17, PA18, PA19, PA21,
PA22, PA23, PA24, PA25, PA26, PA27, PA35, PA37, PA40, PA41
4.3.13 The Trent Valley IDB also identified the following sites as being outside the Board’s district,
though within the Board’s catchment:
• PA14, PA15
4.3.14 The Upper Witham IDB identified that the potential mineral sites PA27 and PA19, and the
adjacent existing site of Girton are split by an existing raised flood defence. Raised flood
defences are also present along the nearby section of the River Piddle. Upper Witham IDB
stated that it is essential that the raised flood defences are protected or enhanced.
4.3.15 The Upper Witham IDB stated that the potential mineral site PA10 is located upstream of the
village of Stapleford, which lies approximately 2km to the east of Nottinghamshire, and is
known to be at risk of flooding. The IDB stated that restoration of the site would present an
opportunity to reduce the flood risk posed to the settlement.
4.3.16 Doncaster East IDB was consulted on the draft Minerals Level 1 SFRA, though did not provide
a response. However the potential mineral sites PA02 and PA38 are located within the IDB
district and therefore Doncaster East IDB should be consulted should these sites be brought
forward for development.
4.3.17 Consent is required from IDBs for any works in, over, under or within 9 metres of any Board
maintained watercourse. Any alterations to a watercourse, for example infilling, diversion or
culverting within an IDB district, would also require consent from the relevant IDB.
4.4 Data/Information Requested
4.4.1 The following data was collected from the above stakeholders and integrated in a GIS system
to facilitate a review of the datasets:
• Records of overtopping and breach events associated with C&RT assets within and in
proximity to Nottinghamshire;
• Details of any management that was carried out by the C&RT to maintain water levels
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in the network during a flood event;
• IDB data:
– Asset location data;
– Historic records of flooding;
– GIS layer of IDB area;
• Environment Agency modelling outputs for Main Rivers;
• National Flood and Coastal Defence Database (NFCDD) / Asset Information
Management System (AIMS);
• Areas Benefiting from Flood Defences;
• Any records of flooding/flood warning areas/flood zones;
• Details of any upcoming flood risk management work / studies;
• Details of any flood alleviation schemes;
• Any locations or particular assets that are susceptible to flooding;
• GIS layers of assets (including mineral site boundaries, historic landfills etc.);
• Ordnance Survey (OS) Mapping;
• Emergency service details of flood incident callouts;
• National Receptor Database;
• Source Protection Zones; and
• WFD Classifications.
4.4.2 Additional data was acquired through the Environment Agency’s GeoStore:
• Flood Map for Planning (Rivers and Sea) Flood Zones 2 and 3;
• Statutory Main Rivers and Detailed River Network;
• The updated Flood Map for Surface Water;
• Flood Warning Areas;
• Historical Flood Map;
• Bedrock and Superficial Deposits Aquifer Designations;
• Areas Susceptible to Groundwater Flooding.
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4.5 Data Presentation
4.5.1 Using the GIS layers collected, nine Nottinghamshire-wide overview maps and four sets of
thirteen detailed 1:50, 000 scale map insets covering the whole of Nottinghamshire were
produced as shown in Table 4.1 to visually assist NCC in their site allocation decision making
process.
Table 4-1: SFRA Mapping Contents
Contents Appendix Figures
County Overviews
Study Area, Main Watercourses & Inset Index A-1
Environment Agency Flood Zones (Undefended) A-2
IDB Areas A-3
Groundwater Source Protection Zones A-4
Environment Agency Bedrock and Superficial Deposits Aquifer Designations
A-5(a-b)
Areas Susceptible to Groundwater Flooding A-6
Flood Warning Areas A-7
Existing (Active and Worked Out) and Potential Minerals Sites A-8(a-b)
1:50,000 Scale County Insets
Fluvial (River Flooding) B1 to B13
Pluvial (Surface Water Flooding) C1 to C13
Other Potential Sources of Flooding & Historical Flooding D1 to D13
Detailed Modelled Flood Outlines (Defended)
E1 to E13.
(excl. E5 and E7 where no data available)
4.6 GIS Data Review
Fluvial and Tidal Flood Data
4.6.1 GIS layers of the Environment Agency’s undefended Flood Zone 2 (0.1% annual exceedance
probability (AEP) event) and Flood Zone 3 (1% AEP event) outlines were provided.
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4.6.2 The Environment Agency’s Flood Zone Maps consist of a mixture of flood outlines derived
through detailed numerical hydraulic modelling, where available and national broad-scale
(coarse) modelled flood outlines. The Environment Agency updates their Flood Map on a
quarterly basis to include the results of new flood mapping studies undertaken to improve and
refine the Flood Zones.
4.6.3 These Flood Zone Maps define the extent of flooding ignoring the presence of defences and
the fact that their presence cannot always be assured. The reason for this approach is to
make an allowance for residual flood risk in the event of a failure or breach/overtopping of the
flood defences. This conservative approach over time will reduce reliance on flood defences
and raises the awareness of flood risk in defended areas to help ensure that it is managed
appropriately as part of development proposals.
4.6.4 If a potential minerals site falls within an undefended Environment Agency Flood Zone 2 or
Flood Zone 3, all available detailed modelled Flood Zones (GIS layers) should then be
referred to.
4.6.5 A number of detailed hydraulic modelling studies have been undertaken along watercourses
within the Study Area as part of the SFRAs (as mentioned in Section 5) or Environment
Agency Strategic Flood Risk Mapping (SFRM) and Water and Environmental Management
(WEM) framework studies. Table 4.2 details the availability of modelled output provided by the
Environment Agency. All modelled outputs take account of the presence of flood defences.
4.6.6 The various defended scenario detailed modelled outlines however provide an incomplete
picture across Nottinghamshire for all the required Flood Zones. Therefore the latest
undefended Flood Zone 2 and Flood Zone 3 maps should be used to provide the first basis for
assessing the risk of fluvial and, in the case of the River Trent downstream of Cromwell Weir,
tidal flooding against the potential minerals sites for the purposes of the Sequential Test.
These are provided in Figure A-2 at Appendix A and in the Fluvial Flooding map insets
provided in Figures B1 to B13 at Appendix B. The Environment Agency regularly updates its
flood zones following new modelling studies and therefore the Environment Agency website
should also be consulted for the most up-to-date flood zone information.
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4.6.7 Flood Zone 3b is defined in the NPPF as land where water has to flow or be stored in times of
flood. For the purposes of this Level 1 SFRA Flood Zone 3b is identified as the 4% AEP event
or 5% AEP event defended outline, utilising detailed model outputs where available. Where no detailed hydraulic modelled data is available for Flood Zone 3b, the Flood Zone 3a extent illustrated should be adopted as a conservative proxy for the functional floodplain until such a time that more detailed information is available, such as completion of
a Level 2 SFRA, an Environment Agency study or a site-specific FRA, as recommended by
the NPPF. Flood Zone 3b is mapped in Figures E1 to E13.
4.6.8 Flood defences are structures which affect flow in times of flooding and therefore reduce the
risk of water from entering property. They generally fall into one of two categories; 'formal' or
'informal'.
4.6.9 A 'formal' flood defence is a structure which has been specifically built to control floodwater. It
is maintained by its owner or statutory undertaker so that it remains in the necessary condition
to function. In accordance with the FWMA, the Environment Agency has powers to construct
and maintain defences to help protect against flooding. NCC has similar powers on ordinary
watercourses within Nottinghamshire.
4.6.10 An 'informal' defence is a structure that has not necessarily been built to control floodwater
and is not maintained for this purpose. This includes road and rail embankments and other
linear infrastructure (buildings and boundary walls) which may act as water retaining structures
or create enclosures to form flood storage areas in addition to their primary function.
4.6.11 Information on ‘formal’ raised flood defences was provided by the Environment Agency’s
Asset Information Management System (AIMS). The dataset lists major structures and flood
defences maintained by the Environment Agency, providing information on the location, type,
condition and standard of protection.
4.6.12 Raised defences may present a residual risk of flooding in the unlikely event of a major breach
failure. The likelihood of this and potential locations where it could occur are dependent on the
condition of the defences, maintenance regime and level of inspection/monitoring undertaken.
The extent and impact of such an event is inevitably linked to the location at which the breach
occurs and how long it is left to continue after the onset.
4.6.13 A study of informal flood defences has not been made as part of this assessment. Part 1,
Section 21 of the FWMA states that:
4.6.14 “(1) A lead local flood authority must establish and maintain:
a) a register of structures or features which, in the opinion of the authority, are likely to have a significant effect on flood risk in its area; and
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b) a record of information about each of those structures or features, including information about ownership and state of repair.”
4.6.15 Should any changes be planned in the vicinity of road or railway crossings over rivers in the
study area it would be necessary to assess the potential impact on flood risk to ensure that
flooding is not made worse either upstream or downstream. Smaller scale informal flood
defences should be identified as part of site specific FRAs and the residual risk of their failure
assessed. As NCC develops an Asset Register, this will provide a database which can be
consulted in the process of developing a site-specific FRA. It should be noted that, currently,
limited information is available regarding third party flood defences.
4.6.16 The locations of ‘formal’ raised flood defences in the study area are presented in Figures B1-
B13 included at Appendix B, and the Figures E1-E13 at Appendix E. The Environment Agency
has provided a GIS layer of official Flood Storage Areas. There are none located within
Nottinghamshire on this layer.
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Table 4-2: Detailed Modelled Flood Studies provided for use in the SFRA Section of Watercourse Study
Trent (Sawley to Radcliffe Viaduct) Greater Nottingham SFRA, Revised Oct 2010
Trent (Radcliffe Viaduct to Cromwell Weir)
River Trent and Tributaries at Newark SFRM2, Halcrow, July 2011
Trent (Cromwell Weir to Keadby)
Tidal Trent Flood Risk Management Study, Black and Veatch, April 2005
Trent (Winthorpe Bridge to Trent Falls)
Tidal Trent Modelling & Mapping Study, Mott MacDonald, December 2013.
Tidal Trent Modelling and Mapping Study Addendum, January 2015.
Idle River Wye SFRM, Halcrow, August 2010
Baker Lane Baker Lane Brook, SFRM, March 2009
Leen Leen (QMC) and Day Brook Hydraulic Modelling Study, Black and Veatch, May 2011
Leen
River Leen and Day Brook SFRA, Black and Veatch, Sept 2008 (where this overlaps with the Leen (QMC) and Day Brook Hydraulic Modelling Study the former is superseded).
Fairham Fairham Brook Flood Risk Mapping Study. Final Report, Environment Agency September 2008
Greet Nottingham Tributaries SFRM, JBA, January 2014
Meden River Meden Flood Risk Mapping Strategy, JBA, June 2008
Ryton River Ryton SFRM, JBA, March 2008
Maun River Maun Flood Risk Mapping, JBA, March 2007
Dover Beck Nottingham Tributaries SFRM, JBA, January 2014
Crock Dumble Nottingham Tributaries SFRM, JBA, January 2014
Cocker Beck Nottingham Tributaries SFRM, JBA, January 2014
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4.6.17 The Environment Agency has also provided its Areas Benefiting from Defences (ABDs)
dataset showing areas benefitting from protection from flooding to a 1% AEP Standard of
Protection (SoP) as is included in the selection of Figures at Appendix E.
Climate Change
4.6.18 To ensure sustainable development now and in the future, the NPPF requires that the effects
of climate change should be taken into account in an SFRA and that flood outlines delineating
climate change should be presented. The Environment Agency document: ‘Climate change
allowances for planners’30 provides guidance on how to account for potential future climate
change.
4.6.19 Table 4.3 outlines allowances for climate change when considering river flow and rainfall
intensity:
Table 4-3: Recommended national precautionary sensitivity ranges for peak rainfall intensity and peak river flow*
Parameter 1990 to 2025 2025 – 2055 2055 – 2085 2085 – 2115
Peak rainfall intensity +5% +10% +20% +30%
Peak river flow +10% +20%
*Adapted from Table 2 of ‘Climate change allowance for planners’
4.6.20 Detailed modelled fluvial outlines for Flood Zone 3, including a 20% increase in peak flows
allowing for the effects of climate change up to 2114, where available, have been presented in
Appendix E for the defended scenarios.
4.6.21 In areas where no detailed hydraulic modelled data is available to define Flood Zone 3 plus
climate change, Flood Zone 2 may be adopted as a conservative proxy until such time that
more detailed information is available, such as completion of a Level 2 SFRA, an Environment
Agency SFRM study or a site-specific FRA, as recommended by the NPPF. This is not to say
that the entire area used as a proxy is representative of Flood Zone 3 plus an allowance for
climate change, but moreover that the boundary of Flood Zone 3 plus an allowance for climate
change falls somewhere within that area.
30 Environment Agency (2013) Climate change allowances for planners: Guidance to support the National Planning Policy Framework
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4.6.22 Sites illustrated alongside raised defences or within ABDs will require consideration of residual
risk of flooding in the event of catastrophic failure of the defences (e.g. breach) as part of a
Level 2 SFRA or a site specific FRA. The Environment Agency should be consulted to confirm
existing availability of any such modelling, which may already have performed breach
analyses.
4.6.23 Using proxy data to define Flood Zones presents a series of issues, limitations and
uncertainties. This is especially true when Flood Zone 3a is used as a proxy for Flood Zone
3b. In urban areas, watercourses often flow in deep and canalised channels and through
culverts or tunnels. However, broad-scale modelled outlines assume a ‘bank-full’ state prior to
flooding and therefore, large areas are shown to be flooded at both Flood Zone 3 and Flood
Zone 2.
4.6.24 The level of confidence assigned to each Flood Zone is a result of the level of assumptions
and limitations in the modelling approach when deriving that Flood Zone.
Flood Warnings
Data Sources and Requirements
4.6.25 The Civil Contingencies Bill requires that the Environment Agency “maintain arrangements to
warn the public of emergencies”. As a Category 1 responder, the Environment Agency has a
duty to maintain arrangements to warn, inform, and advise the public in relation to particular
emergencies.
4.6.26 NCC also has a duty under the Civil Contingencies Act (CCA) to warn and inform the public
and this is done mainly through the Communications Unit.
4.6.27 The Environment Agency has provided a GIS layer of areas benefiting from the Environment
Agency Flood Warning system which should be used by emergency planners in conjunction
with the Flood Zone maps and flood defence information to assist in developing emergency
plans for areas at risk of flooding with the study area.
Mapping
4.6.28 Figure A-7 at Appendix A illustrates coverage of the Environment Agency’s Flood Warning
Areas within Nottinghamshire.
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Flooding from Surface Water
4.6.29 Overland flow and surface water flooding typically arise following periods of intense rainfall,
often of short duration, that is unable to soak into the ground or enter drainage systems. It can
run quickly off the land and result in localised flooding.
Updated Flood Map for Surface Water
4.6.30 The Environment Agency has undertaken modelling of surface water flood risk at a national
scale and produced mapping identifying those areas at risk of surface water flooding during
three events, 3.33% AEP, 1% AEP and 0.1% AEP. The latest version of the mapping is
referred to as the uFMfSW and the extents have been made available to NCC as GIS layers.
4.6.31 The modelling represents a significant improvement on previous mapping, namely the Flood
Map for Surface Water (FMfSW) (2010) and the Areas Susceptible to Surface Water Flooding
(AStSWF) (2009).
Mapping
4.6.32 The uFMfSW is illustrated in Figures C1 to C13 at Appendix C, highlighting areas at risk of
surface water flooding in the future. To support the 2011 SFRA, Ashfield District Council
(ADC) provided data from its 2007 Flood Risk Survey. This is provided in Figures D1 to D13 at
Appendix D.
Climate Change
4.6.33 The uFMfSW does not include a specific scenario to determine the impact of climate change
on the risk of surface water flooding. However a range of three annual exceedance probability
events have been undertaken, 3.3%, 1% and 0.1% and therefore it is considered appropriate
to use the 0.1% AEP event as a substitute dataset to provide an indication of the implications
of climate change.
Flooding from Groundwater
4.6.34 Groundwater flooding usually occurs in low lying areas underlain by permeable rock and
aquifers that allow groundwater to rise to the surface through the permeable subsoil following
long periods of wet weather.
4.6.35 Low lying areas may be more susceptible to groundwater flooding because the water table is
usually at a much shallower depth and groundwater paths tend to travel from high to low
ground.
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4.6.36 Figure A-6 in Appendix A presents the Environment Agency’s dataset: Areas Susceptible to
Groundwater Flooding (AStGWF), which indicates where groundwater may emerge due to
certain geological and hydrogeological conditions. This information is shown as a proportion of
1km grid squares where there is potential for groundwater emergence. It does not take
account of the chance of flooding from groundwater rebound.
4.6.37 The susceptible areas are represented by one of four area categories (listed below) showing
the percentage of each 1km2 that is susceptible to groundwater emergence.
• < 25%;
• >= 25% <50%;
• >= 50% <75%; and
• >= 75%.
4.6.38 The data does not show where flooding is likely to occur, but instead should be used at a
strategic level to indicate areas for further investigation. The data is relatively broad and
susceptibility varies greatly throughout NCC.
Groundwater Source Protection Zones
4.6.39 The Environment Agency has also provided their Groundwater Source Protection Zones
(GWSPZs) for Nottinghamshire to assist with this SFRA. The GWSPZs are defined for 2000
groundwater sources such as wells, boreholes and springs used for public drinking water
supply. These zones show the risk of contamination from any activities that might cause
pollution in the area. Generally, the closer the contaminating activity, the greater the risk
posed to the aquifer. The maps show three main zones (inner, outer and total catchment).
4.6.40 The zones are used in conjunction with the Environment Agency’s Groundwater Protection
Policy (GPP) to set up pollution prevention measures in areas which are at a higher risk, and
to monitor the activities of potential polluters nearby. The shape and size of a zone depends
on the condition of the ground, how the groundwater is removed, and other environmental
factors. Groundwater source catchments are divided into three Source Protection Zones as
follows:
• SPZ1 – Inner Protection Zone - Defined as a 50 day travel time from any point below
the water table to the source. This zone has a minimum radius of 50 metres;
• SPZ2 – Outer protection zone - Defined by a 400 day travel time from a point below
the water table. This zone has a minimum radius of 250m or 500m around the source,
depending on the size of the abstraction;
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• SPZ3 – Total Catchment Zone - Defined as the area around a source within which all
groundwater recharge is presumed to be discharged at the source. In confined
aquifers, the source catchment may be displaced some distance from the source. For
heavily exploited aquifers, the final Source Catchment Protection Zone can be defined
as the whole aquifer recharge area where the ratio of groundwater abstraction to
aquifer recharge (average recharge multiplied by outcrop area) is >0.75. There is still
the need to define individual source protection areas to assist operators in catchment
management.
Mapping
4.6.41 The Environment Agency’s GWSPZs have been presented as a thematic map in Figure A-5(a)
at Appendix A.
Aquifer Designation
4.6.42 The Environment Agency has provided their Aquifer Designation Maps for Nottinghamshire in
digital GIS format to assist with this SFRA.
4.6.43 Groundwater is an important strategic resource with three-quarters of all the groundwater
pumped from boreholes or taken from springs used for mains water supply. It directly supplies
nearly a third of the drinking water in England and Wales. In some areas it is the only available
drinking water resource. It also supplies nearly all those who do not have mains water.
4.6.44 Groundwater is not just for private domestic use: many hospitals, bottling and food processing
plants also rely on their own groundwater supplies, as do major manufacturing and other
industries. There are advantages in using groundwater for both public and private supplies:
compared to surface water, it is of relatively high quality and usually requires less treatment
prior to use, even for drinking and other potable purposes.
4.6.45 The widespread presence of groundwater means that any material spilt on or applied to the
ground has the potential to reach the water table. Whether it will or not depends on the
material involved and the ground conditions at that site. Pollutants introduced by people can
overwhelm the natural capacity of the ground to deal with them.
4.6.46 If human activities do pollute groundwater, it is very difficult to return it to its original condition.
Processes that take days or weeks in surface water systems may take decades to centuries in
groundwater. This is because of the relatively slow rates of groundwater flow and the reduced
microbiological activity below the soil zone (due to the general lack of oxygen and nutrients).
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4.6.47 Protecting groundwater is therefore essential. The subsurface environment is inaccessible and
complex and groundwater pollution can be very difficult to detect and may not become evident
until a water supply or spring is affected. Pollutants may take months or years to migrate from
the source to a receptor or to a point where they can be detected.
4.6.48 Aquifer designation relates to the importance of aquifers as groundwater resources such as
drinking water supply, as well as for supporting surface water flow31. The use of infiltration
techniques will be dependent on the ground and groundwater conditions. However, other
SuDS techniques may be suitable even if groundwater conditions preclude infiltration.
The Environment Agency provides the following definitions for the Aquifer Designations:
• “Principal Aquifer - layers of rock or drift deposits that…usually provide a high level of
water storage. They may support water supply and/or river base flow on a strategic
scale. In most cases, principal aquifers are aquifers previously designated as major
aquifer;
• Secondary Aquifer A - permeable layers capable of supporting water supplies at a
local rather than strategic scale, and in some cases forming an important source of
base flow to rivers. These are generally aquifers formerly classified as minor aquifers;
• Secondary Aquifer B - predominantly lower permeability layers which may store and
yield limited amounts of groundwater due to localised features such as fissures, thin
permeable horizons and weathering. These are generally the water-bearing parts of
the former non-aquifers;
• Undifferentiated Strata - has been assigned in cases where it has not been possible to
attribute either category A or B to a rock type. In most cases, this means that the layer
in question has previously been designated as both minor and non-aquifer in different
locations due to the variable characteristics of the rock type.”
4.6.49 Factors that will influence the vulnerability of an aquifer to contamination include whether the
aquifer is classed as confined or unconfined; the depth of the aquifer; whether a pathway
exists to the aquifer i.e. if impermeable layers lie above an aquifer; and the soil vulnerability.
4.6.50 Some strata have a high leaching potential and have very little ability to slow or halt the
progress of contaminants and transmit them readily to the underlying aquifer. Other strata
have a low leaching potential and are thus either impermeable or have a number of natural
factors that can slow or stop the leaching of contaminants. Principal Aquifers with a high
vulnerability tend to be those with a more permeable surface geology.
31 Environment Agency (2015) Aquifer Designation Maps. http://apps.environment-agency.gov.uk/wiyby/117020.aspx
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4.6.51 It is important to note that Aquifer Designation mapping is intended to be used at a strategic
scale and further site-level investigation may be necessary.
Mapping
4.6.52 The Environment Agency’s Aquifer Maps have been presented as thematic maps in Figure A-
5(b) and Figure A-5(c) at Appendix A.
Sewer Flooding
4.6.53 During heavy rainfall, flooding from the sewer system may occur if:
1. The rainfall event exceeds the capacity of the sewer system/drainage system:
Sewer systems are typically designed and constructed to accommodate rainfall events
with a 3.3% AEP or less. Therefore, rainfall events with a return period of frequency
greater than 3.3% AEP would be expected to result in surcharging of some of the sewer
system. While TWUL and AWS are concerned about the frequency of extreme rainfall
events, it is not economically viable to build sewers that could cope with every extreme
rainfall event.
2. The system becomes blocked by debris or sediment:
Over time there is potential that road gullies and drains become blocked from fallen
leaves, build-up of sediment and debris (e.g. litter).
3. The system surcharges due to high water levels in receiving watercourses:
Within the study area there is potential for river outlets to become submerged due to high
river levels. When this happens, water is unable to discharge. Once storage capacity
within the sewer system itself is exceeded, the water will overflow into streets and
potentially into houses. Where the local area is served by ‘combined’ sewers i.e.
containing both foul and storm water, if rainfall entering the sewer exceeds the capacity of
the combined sewer and storm overflows are blocked by high water levels in receiving
watercourses, surcharging and surface flooding may again occur but in this instance
floodwaters will contain untreated sewage.
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Historic Records
4.6.54 Areas at risk from sewer flooding have been determined through review of records from DG5
registers provided by STW and AWS. In order to fulfil statutory commitments set by OFWAT,
water companies must maintain verifiable records of sewer flooding, which is achieved
through their DG5 registers. Water companies are required to record flooding arising from
public foul, combined or surface water sewers and identify where properties have suffered
internal or external flooding. The DG5 register does not however indicate areas or properties
at risk of future flooding.
4.6.55 The data provided by STW is limited as it simply indicates areas reported to STW that have
experienced flooding during the last 35 year period as a result of insufficient hydraulic capacity
in the sewer network. This causes overloading and is considered by STW to be due to a
permanent problem such as a small pipe, flat gradient etc. STW has stated that the records do
not include instances where flooding has occurred due to temporary operational problems
such as blockage, collapse or operational failure etc. Properties remain on the register until
they are removed due to;
• implementation of a flood alleviation scheme which provides a robust level of
protection against flooding; or
• new information becoming available such that the property or area no longer meets
the required criteria to be on the register, for example a blockage, flooding from a
watercourse or private sewer etc.
4.6.56 Whilst a property or area remains on the register, it may benefit from a short-term measure to
protect it from recurring flooding until a flood alleviation scheme is developed to provide more
robust flood protection.
4.6.57 It should be noted that records only appear on the DG5 register where they have been
reported to STW, and as such they may not include all instances of sewer flooding.
4.6.58 AWS confirmed that they held no records of sewer flooding within the Study Area. Instances of
STW sewer flooding were also provided by ADC within their 2007 Flood Risk Survey GIS
layer.
4.6.59 STW should be consulted for further information to support site-specific FRAs within
Nottinghamshire.
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Mapping
4.6.60 Detailed maps provided in Figures D1 to D13 at Appendix D illustrate incidents of internal and
external surface water, foul and combined water flooding for Nottinghamshire. Instances of
sewer flooding provided by ADC included within their 2007 Flood Risk Survey have also been
included in Figures D1 to D13 at Appendix D.
Artificial Sources
4.6.61 The Environment Agency’s Risk of Flooding from Reservoirs Mapping32 identifies areas that
could be flooded if a large33 reservoir were to fail and release the water it holds.
4.6.62 Reservoirs in the UK have an extremely good safety record. The Environment Agency is the
regulatory authority for the Reservoirs Act 1975 in England and Wales. All large reservoirs
must be inspected and supervised by reservoir panel engineers on an annual basis.
4.6.63 NCC provided a record of reservoirs located with Nottinghamshire, identified in Figures D1-
D13 at Appendix D. A number of 79 reservoirs having a capacity of 25,00m3 of greater are
identified within Nottinghamshire. Of these, one reservoir has been abandoned and four are
identified as being under construction.
4.6.64 The C&RT maintains over 2,000 miles of canals and rivers in the UK, including a number of
canals running through Nottinghamshire. The C&RT provided records of breaching and
overtopping events associated with canals they operate within Nottinghamshire. These have
been presented in Figure E1-13 at Appendix E.
Minerals and Waste Sites
Data Sources and Requirements
4.6.65 NCC has provided a GIS layer of 37 potential future minerals extraction site allocations put
forward by the industry in response to a call for sites exercise for consideration at the site
allocation phase. A number of these sites are currently unused allocations from the Adopted
Minerals Local Plan (2005). A summary of the sites is detailed below in Table 4.4. A GIS layer
of the existing operational mineral extraction sites was also provided to illustrate potential
extensions.
32 Environment Agency (2014) Risk of Flooding from Reservoirs. Accessed: 21/05/14. http://watermaps.environment-agency.gov.uk/wiyby/wiyby.aspx?lang=_e&topic=reservoir&layer=0&x=456500&y=341500&scale=10&location=Nottingham%2c+City+of+Nottingham#x=463151&y=363063&scale=5 33 A large reservoir is one that holds over 25,000 cubic metres of water, equivalent to approximately 10 Olympic sized swimming pools.
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Table 4-4 Potential Allocation Mineral Extraction Sites
Proposed Allocation Site Reference
Site Name Mineral Type Area (Ha) OSNGR Easting
OSNGR Northing
PA01 Barnby Moor Sand and Gravel 45 466474 385341
PA02 Bawtry Road, Bryans Close
Sand and Gravel 18 467680 395140
PA03 Besthorpe East
Sand and Gravel 24 482320 363130
PA04 Besthorpe South
Sand and Gravel 66 481230 361970
PA05 Bestwood 2 East
Sherwood Sandstone 9 457258 352543
PA06 Botony Bay Sand and Gravel 113 467480 383141
PA07 Bulcote Farm Sand and Gravel 146 466670 344213
PA08 Burridge Farm Sand and Gravel 54 480382 357250
PA09 Carlton Forest Extention
Sherwood Sandstone 14 459894 382556
PA10 Coddington Sand and Gravel 129 484118 355449
PA11 Cromwell South
Sand and Gravel 52 480376 361090
PA14 East Leake East
Sand and Gravel 28 456954 324791
PA16 East Leake North
Sand and Gravel 15 456719 325264
PA17 Flash Farm Sand and Gravel 71 475873 355388
PA18 Foxholes Farm Sand and Gravel 34 478685 360175
PA19 Girton West Sand and Gravel 14 482098 368703
PA20 Holbeck Magnesian Limestone 35 453711 373515
PA21 Home Farm Sand and Gravel 170 477954 355137
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Proposed Allocation Site Reference
Site Name Mineral Type Area (Ha) OSNGR Easting
OSNGR Northing
PA22 Langford Quarry East
Sand and Gravel 31 481995 359580
PA23 Langford Quarry North
Sand and Gravel 31 481731 361073
PA24 Langford Quarry South
Sand and Gravel 47 481146 359580
PA25 Langford Quarry West
Sand and Gravel 35 480635 360552
PA26 Little Carlton Sand and Gravel 73 477494 357698
PA27 Manor Farm Sand and Gravel 151 483863 370054
PA28 Nether Langwith West
Magnesian Limestone 31 453435 369431
PA29 Red Barn Sherwood Sandstone 13 461039 383369
PA31 Scrooby North Sand and Gravel 9 465436 389794
PA32 Scrooby South Sand and Gravel 9 465744 388861
PA33 Scrooby Top Sherwood Sandstone 20 465010 389570
PA35 Sturton Le Steeple East
Sand and gravel 32 481788 384702
PA37 Kirton West Brick Clay 25 469509 368834
PA38 Steetley Limestone 20 455570 379460
PA38 Finningley Extension
Sand and gravel 30 469770 398804
PA39 Bantycock Extn Gypsum 109 481484 348473
PA40 Shelford East Sand and Gravel 140 467546 342840
PA41 Shelford West Sand and Gravel 228 465590 342358
PA46 Barton in Fabis Sand and gravel 79 453142 333774
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Mapping
4.6.66 The existing and potential future minerals sites have been included in all maps presented in
Appendices A-E. When overlain with flood risk and historical flooding GIS layers, it is possible
to determine which of the potential minerals sites are located in areas at risk of flooding and to
what extent to allow informed decisions regarding site allocation to be made.
4.6.67 Flood risk information for the potential future minerals sites is presented in tabular form in
Appendix F.
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5 FLOOD RISK IN NOTTINGHAMSHIRE
5.1 Introduction
5.1.1 This section describes the methodology used in the production of mapping deliverables for the
project and the assessment of flood risk.
5.2 Requirements of the National Planning Policy Framework
5.2.1 The NPPF and the accompanying PPG requires SFRAs to present sufficient information on all
flood sources to enable the LPAs and the MPA within the Study Area to apply the Sequential
Test in their administrative areas. This information should be presented graphically where
possible as a series of figures and/or maps. In addition, the assessment of probability should
also account for the effects of climate change on a flood source for the lifetime of any
development that is proposed.
5.3 Historical Flooding
5.3.1 There have been numerous historical flood events in Nottinghamshire. A GIS layer of the
Environment Agency’s Historic Flood Map (HFM) was obtained to support this SFRA Update
and is illustrated within Figures D1-D13 at Appendix D.
5.3.2 Records of major historical flooding events along the River Trent through Nottinghamshire as
provided within the Trent Catchment Flood Management Plan (CFMP)34 have been
summarised below.
5.3.3 The River Trent catchment has a long history of flooding, with the earliest reports dating back
to 530 A.D. More detailed reports start to appear in the 1200s, making reference to
embankments being overtopped or breached and the damage that was done. The flooding
history provided by the British Hydrological Society (BHS) Chronology of British Hydrological
Events35 provides evidence of flooding from a wide range of sources, including fluvial and
tidal, and, to a relatively lesser extent, surface water and groundwater. Overtopping and
breach of flood embankments has long been a common cause of flooding. Table 3.1.1 of the
CFMP details some of the most notable flooding events that have occurred in the Trent
catchment.
34 Environment Agency (2010) River Trent Catchment Flood Management Plan. http://www.environment-agency.gov.uk/research/planning/114350.aspx 35 British Hydrological Society (2014) Chronology of British Hydrological Events. http://www.dundee.ac.uk/geography/cbhe
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5.3.4 The most significant river flooding on record occurred in February 1795. Widespread fluvial
flooding resulting from a rapid thaw and over a week of constant heavy rainfall occurred on the
River Trent at Burton, Nottingham and Newark. Tidal flooding breached embankments at
Morton and Spalford, with flooding extending to Lincoln. The extent and depth of flooding was
considered by The Fluvial Trent Strategy36 to be the worst on record. The flooding covered an
area of more than 8,000 ha to a depth of more than 3 m in places.
5.3.5 The most severe tidal flooding took place in October/November 1954 as a result of a series of
tidal surges. Other large events occurred in October 1875, March 1932, March 1947,
December 1965, winter 2000 and summer 2007.
5.3.6 More minor flood incidents have been recorded along the Day Brook and River Greet in June
2010 and November 2012 respectively.
5.3.7 Flooding resulting from overtopping of the Nottingham Canal was experienced pre 1952 in
Cossall (in Broxtowe).
5.3.8 The individual SFRAs for Nottingham City and the other seven districts/boroughs within
Nottinghamshire provide further details of historical flooding events within their locality.
5.3.9 It is noted that the number of properties having suffered internal flooding may be greater than
those recorded as some residents may have chosen not to report flooding for fear of impact on
household insurance.
5.3.10 Widespread flooding occurred during the 23rd of July 2013, as a result of heavy rainfall during
the 22nd and 23rd of July 2013. A number of settlements in Nottinghamshire were affected by
flooding during this event37;
36 Environment Agency (2004) The Fluvial Trent Strategy. 37 Environment Agency (2013) Final Nottinghamshire Event Analysis Report.
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• Arnold
• Calverton
• Carlton
• East
Bridgford
• Eastwood
• Gedling
• Hucknall
• Kimberley
• Lowdham
• Mapperley
• Newthorpe
• Nuthall
• Southwell
• Thurgarton
5.3.11 In Southwell over 400 properties experienced exterior flooding, of which over 250 were also
flooded internally. Southwell has also been affected by flooding on a number of other
occasions, including a notable extreme event in June 2007.
5.3.12 None of the historical flooding incidents recorded as part of the ADC Flood Risk Survey
undertaken in 2007 coincide with the potential minerals sites or within their immediate vicinity.
The Environment Agency’s Historic Flood Map illustrates a number of potential sand and
gravel sites were inundated in the past, predominantly those along the Trent Valley and at two
isolated sites on the western outskirts of Mission (PA02, Bawtry Road) and close to Finningley
(PA38, Finningley Extension) as a result of flooding from the River Idle.
5.4 Fluvial Flooding
5.4.1 The predominant risk of flooding within Nottinghamshire is fluvial and tidal flooding from the
overtopping of surface watercourses including rivers, streams and drainage channels (i.e.
flows exceeding their bank-full capacity). The main watercourses within the SFRA Study Area
are illustrated in Appendix A, Figure A-1.
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River Trent
5.4.2 The River Trent is the dominant catchment draining Nottinghamshire. Major tributaries join the
River Trent from three main areas including;
• Peak District (River Dove, River Derwent and River Erewash);
• South Midlands (River Sow, River Tame and River Soar); and
• Lower catchment (River Torne and River Idle).
5.4.3 The River Trent bisects the Greater Nottingham administrative area, flowing in a north-easterly
direction through all of the LPAs administrative areas (except Ashfield and Mansfield) across a
broad and low relief alluvial floodplain. The River Trent rises in the Staffordshire Moorlands
and is joined by its major tributaries in the upper catchment before flowing northeast towards
the Humber Estuary.
5.4.4 A review of the National River Flow Archive (NRFA) database38 highlighted that the Trent
catchment is predominantly impervious with the catchment consisting largely of glacial clay
and alluvium on top of Mercia Mudstone, but also of some sandstone and limestone. The
River Trent has little or no hydrological interaction with the underlying aquifer however the
catchment through the study area comprises extensive terrace gravels and alluvium within the
river valleys which maintain its base flow.
5.4.5 The Environment Agency confirmed that the River Trent is tidally influenced downstream from
Cromwell Lock in the Newark and Sherwood District Council (NSDC) area and its tidal
dominance is downstream of Gainsborough, which includes the left bank within the Bassetlaw
District Council (BDC) area.
River Soar
5.4.6 The River Soar is a major tributary of the River Trent flowing generally northwards through
Leicestershire. It forms the south-western border of Rushcliffe where it is joined by Kingston
Brook and continues towards its confluence with the River Trent at Trentlock between Long
Eaton and Ratcliffe-on-Soar.
5.4.7 The source of the river originates near Hinckley in Leicestershire proceeding to flow north east
through Leicester where it is joined by the Grand Union Canal, River Sence, River Wreake
and Rothley Brook upstream of the Greater Nottingham area.
38 Environment Agency (2004) The Fluvial Trent Strategy.
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5.4.8 The River Soar catchment is largely characterised by clay and alluvium, and is known to be
rapidly responsive to rainfall events39. A review of the NRFA database40 highlighted that the
predominant geology of the River Soar catchment is Mercia Mudstone with some sandstones
in the west and Lias clays and limestone in the east. It has a moderate to low relief.
River Erewash
5.4.9 The River Erewash is a tributary of the River Trent comprising a moderate to low relief
catchment which drains Carboniferous Coal Measures with Permian and Triassic bedrock on
the east and southern extents. Approximately 30% of the catchment is urban, whilst the
remaining area is characterised by arable and grazing land uses41. The river flows from north
to south forming the border between Erewash and Broxtowe where it flows through
Attenborough Lakes via breaches caused by mineral extraction before finally discharging into
the River Trent.
River Leen
5.4.10 The River Leen comprises a moderate to low relief catchment flowing from Newstead Abbey
south through Gedling and Ashfield through the centre of Nottingham City towards its
confluence with the River Trent near Lenton. It has a complicated base flow hydrology. The
River Leen drains Magnesian Limestone in the west with Permian Mudstone and Sherwood
Sandstone outcrops in the east, crossing the boundary between the two units several times
before reaching the River Trent to the south-west of Nottingham. A significant fraction of the
lower catchment is urban (approximately 50%). Other land uses include arable and grazing42.
5.4.11 In the past, the Greater Nottingham area contained a large number of springs, many of which
were located to the mudstone/sandstone boundary and drained into local river systems
including the Rivers Leen and Trent. However, many tributaries of these rivers and related
springs are believed to have now dried up.
39 Environment Agency, November (2006) River Trent Catchment Flood Management Plan – Scoping Report, Page 38. 40 Centre for Ecology and Hydrology (2011) National River Flow Archive. Soar at Kegworth. http://www.ceh.ac.uk/data/nrfa/data/station.html?28074 41 Centre for Ecology and Hydrology (2011) National River Flow Archive. Erewash at Sandiacre. http://www.ceh.ac.uk/data/nrfa/data/station.html?28027 42 Centre for Ecology and Hydrology (2011) National River Flow Archive. Leen at Triumph Road, Nottingham. http://www.ceh.ac.uk/data/nrfa/data/station.html?28035
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River Maun, River Meden and River Idle
5.4.12 The River Maun and River Meden form the upper catchment of the River Idle, originating in
Ashfield. The River Meden flows generally north eastwards through Market Warsop. The River
Maun also flows north eastwards through Ollerton before converging with the Meden at West
Drayton in Bassetlaw. Continuing northwards through Retford as the River Idle, it is joined by
the River Ryton west of Scafworth and redirects eastwards towards Misterton.
5.4.13 Downstream of Retford, the River Idle drains bedrock of Nottingham Castle Sandstone
Formation and then Mercia Mudstone Group (Mudstone) downstream of its confluence with
the River Ryton and the small settlement of Misson. The underlying bedrock formations are
classified by the Environment Agency as Principal and Secondary B Aquifers respectively.
Downstream of Retford, the River Idle has well defined floodplains34. Between Retford and
Bawtry the floodplain contains a number of Sand and Gravel Minerals Sites, which are
identified as worked out in (see Figure A8) and in the present day form a series of lakes.
5.4.14 The draft Humber River Basin District Flood Risk Management Plan states that there are
significant lengths of minor embankments along the River Idle. The embankments have been
designed to overtop during flood events with a low return period with the intention of
inundating adjacent washland areas.
5.4.15 At its downstream end, the River Idle discharges into the River Trent at the West Stockwith
Pumping Station
5.4.16 A review of the NRFA database43 highlighted that the catchment is comprised predominantly
of low relief, but more moderate relief in the headwaters. Its tributaries rise on Magnesian
Limestone and then traverse an outcrop of Sherwood Sandstone. The lower reaches are
underlain by alluvium and Mercia Mudstone. Approximately 15% of the catchment is urban;
therefore the land use is predominantly rural, inclusive of arable farming.
5.4.17 The River Maun and River Meden are not currently defended by any formal flood defences. A
significant tributary of the River Idle is the Retford Beck joining the right bank from the east.
The lower reaches of the Retford Beck are heavily culverted and are considerably under
capacity to convey resulting flows, causing frequent flooding at culvert entrances.
43 Centre for Ecology and Hydrology (2011) National River Flow Archive. Idle at Mattersey. http://www.ceh.ac.uk/data/nrfa/data/station.html?28015
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5.4.18 The BDC SFRA44 (2009) states the River Idle has very few formal defences as it flows through
Retford. Previously, the channel has been widened to now contain much of the 1 in 20 year
(5% AEP) flows within bank. There are very few features along the River Idle banks to prevent
a 1 in 100 year (1% AEP) flood spilling out of bank onto the adjacent land. Culverts present
along the River Idle cause some backing up of flood water to occur due to the culverts under
Albert Road and Bridgegate.
River Ryton
5.4.19 The River Ryton enters Bassetlaw from the west and flows eastwards through Worksop before
redirecting northwards through Blyth and Bircotes to its confluence with the River Idle.
5.4.20 A review of the NRFA database45 highlighted that the catchment is comprised of moderate
and low relief. The headwaters drain part of the Magnesian Limestone outcrop; with the bulk
underlain by Permian Marl and Sherwood Sandstone with little Superficial Drift deposits. Apart
from Worksop, the catchment is wholly rural and is characterised by mainly arable farming.
5.4.21 The Bassetlaw SFRA (2009) states in Worksop, the River Ryton has few maintained formal
defences. The river passes through culverts in the town centre which are too small to carry a 1
in 100 year (1% AEP) flood event, resulting in water backing up and flooding out of bank onto
the surrounding land.
River Smite
5.4.22 The River Smite flows north eastwards through eastern Rushcliffe in proximity to the
settlements of Barnstone, Aslockton and Flawborough. The river is joined by the River
Whipling east of Aslockton and is a tributary of the River Devon flowing northwards
immediately north east of the study area boundary.
Smaller Watercourses
5.4.23 In addition to these major watercourses, there is an extensive system of streams and smaller
watercourses including:
• River Greet, • Lambley Dumble, • Mill Dame Dyke;
• River Torne, • Carlton Beck, • Beauvale Brook,
• River Poulter, • Grassthorpe Beck, • Boundary Brook,
44 JBA Consulting (2009) Bassetlaw Strategic Flood Risk Assessment 45 Centre for Ecology and Hydrology (2011) National River Flow Archive. Ryton at Blyth. http://www.ceh.ac.uk/data/nrfa/data/station.html?28091
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• Day Brook, • Lowfield Drain, • Nut Brook,
• River Whipling, • Slough Dyke, • Ock Brook,
• Kingston Brook, • Middle Beck, • Golden Brook.
• Fairham Brook,
• Woodborough
Brook, • Laneham Beck,
• Nethergate Brook, • Tinkers Leen, • Saundby Beck,
• Dover Beck, • Retford Beck, • Cocker Beck,
• Ouse Dyke, • Tottle Brook, • Greythorne Dyke,
• Crock Dumble, • Robins Wood Dyke, • Lees Brook, and
• Baker Lane Brook, • Oldcoates Dyke, • Adbolton Brook.
• Polser Brook • Gamston Brook,
Local SFRAs
Ashfield District Council SFRA
5.4.24 ADC completed a Level 1 SFRA46 in February 2009. Flood risk for the district of Ashfield is
considered to be low however some specific locations require further investigation including
the valley of Cuttail Brook, the valley below Sutton Lawn Dam, Mill Lane in Huthwaite and land
to the north of Ashlands Road.
Bassetlaw District Council SFRA
5.4.25 In July 2009 JBA Consulting Ltd completed a Level 1 and Level 2 SFRA44 for BDC. BDC is
mainly at risk of flooding from fluvial sources. The main rivers in the district that pose a risk are
the River Ryton which has few maintained formal defences, the River Idle which has few
formal flood defences and the lower reaches of Retford Beck which are culverted and are
already restricted in their capacity to carry catchment flows.
46 Ashfield District Council (2009) Ashfield Level 1 Strategic Flood Risk Assessment
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Mansfield District Council SFRA
5.4.26 RPS Group undertook a Level 1 SFRA47 in June 2008 for Mansfield District Council (MDC).
The SFRA concluded that Mansfield District Council (MDC) was generally at low risk from
flooding.
Newark and Sherwood District Council SFRA
5.4.27 In July 2009 WSP produced a Level 1 SFRA48 for NSDC. In June 2010 WSP produced a
Level 2 assessment49 which focussed on three strategic sites which are centred on Newark’s
Growth Point. The key finding for the Level 2 SFRA was that the majority of the land fell within
areas of low fluvial flood risk; other sources of flooding also posed a low risk for flooding. A
second phase Level 2 SFRA50 was delivered in 2012 by WSP.
Greater Nottingham SFRA
5.4.28 The Greater Nottingham SFRA51 was completed by Black and Veatch in 2008. The urban area
of Nottingham extends beyond the boundaries of its City Council taking in several surrounding
towns and villages. The SFRA states that within the urban extent there are 20,000 properties
at risk of flooding, on the right and left bank of the River Trent, from a 1 in 100 year event. In a
1 in 100 year event the existing flood defences in Sawley, Attenborough, Rylands, Nottingham
City Centre, Colwick and Burton Joyce overtop into Sawley, Long Eaton, Attenborough,
Dunkirk, Rylands, Nottingham City centre, Colwick, Netherfield and Burton Joyce. For the less
frequent 1 in 1000 year event there is modelled to be more extensive flooding of urban areas
including flooding into West Bridgford, Wilford and Barton- in- Fabis which is presently
protected for the 1 in 100 year event.
5.4.29 Table 5.1 summarises the flood risk findings of each individual district of which the urban area
of Nottingham extends into.
47 RPS Group (2008) Mansfield Level 1 Strategic Flood Risk Assessment 48 WSP (2009) Newark and Sherwood Level 1 Strategic Flood Risk Assessment 49 WSP (2010) Newark and Sherwood Level 2 Part 1 Strategic Flood Risk Assessment 50 WSP (2012) Newark and Sherwood Level 2 Part 2 Strategic Flood Risk Assessment 51 Black and Veatch (2008) Greater Nottingham Level 1 Strategic Flood Risk Assessment
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Table 5-1: Flood Risk Areas identified from the Greater Nottingham SFRA for individual Councils District/Borough SFRA Comments
Broxtowe
River Trent flooding would likely impact Beeston, Toton, Stapleford and Rylands areas.
Some limited locations adjacent to Boundary and Beauvale Brooks (previously modelled by using HECRAS) are at risk of flooding in a 1 in 100 year (1% AEP) event. These locations include around the cricket pitch and upstream of Mansfield Road (Boundary Brook), and at Devonshire Drive and Roehampton Drive (Beauvale Brook). Flooding along Beauvale Brook is affected by the flap valve under the River Erewash defences
Gedling Ouse Dyke modelling revealed a small number of properties at risk from Day Brook.
Nottingham City
Fairham and Nethergate Brooks were modelled by ISIS. This showed that four properties and Fairham Community College at risk from a 1 in 100 year (1% AEP) flood event; with more properties affected in a 1 in 1000 year (0.1% AEP) flood event.
Rushcliffe
Fairham Brook was modelled by ISIS. The 1 in 100 annual flood event is likely to affect many properties in Wilford and Clifton Boulevard.
Grantham Canal and Adbolton, Gamston and Polser Brooks are likely to cause additional flooding behind the River Trent defences.
5.4.30 The Environment Agency provided the hydraulic modelling outlines (in GIS format) used within
the Greater Nottingham SFRA to assist in this SFRA, and included revised flood outlines for
the River Trent completed more recently in October 2010.
River Leen and Day Brook SFRA
5.4.31 Black and Veatch were also commissioned by the Environment Agency, NCiC and Nottingham
Regeneration Limited to carry out a SFRA of the River Leen and Day Brook52. This was
completed in 2008.
5.4.32 The SFRA predicts that major overtopping of the flood defences occurs at Bulwell, Basford,
Bobbers Mill, Radford and Sherwood. Overtopping also affects major transport infrastructure
such as the railway line, tram line and arterial roads in the north and west of Nottingham City.
Generally, the River Leen channel and flood defences are considered to provide around a 1 in
25 year (4% AEP) SoP although flooding commences at a 1 in 5 year (20% AEP) flood event
in parts of Bulwell, Basford and Sherwood.
52 Black and Veatch (2008) River Leen and Day Brook Strategic Flood Risk Assessment
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5.5 Surface Water Flooding
5.5.1 During periods of prolonged rainfall events and sudden intense downpours, overland flow
generated from adjacent higher ground may flow across land and ‘pond’ in low-lying areas
without draining into watercourses, surface water drainage systems or the ground. Intense
rainfall that is unable to infiltrate into the ground or enter drainage systems can quickly run
overland and result in local flooding.
5.5.2 One of the main issues with pluvial flooding is that relatively small changes to hard surfacing
and surface gradients can cause flooding (garden loss and reuse of brownfield sites for
example). This type of flooding is frequently experienced and often very destructive and is
possibly a more serious problem than suggested by historic records. Surface water flooding
does not need a watercourse in close proximity to occur and is exacerbated by areas of highly
impermeable hard standing such as tarmac, or low permeability soils and geology (such as
clayey soils). In developed areas, this flood water can be polluted with domestic sewage
where foul sewers surcharge and overflow.
5.5.3 As a result, minerals development, inclusive of stockpiles and ancillary buildings, could lead to
more frequent surface water flooding and, although not on the same scale as fluvial flooding,
can still cause significant disruption to the site and surrounding land. However, any problems
encountered from pluvial flooding are more likely to inconvenience the operator and are
unlikely to be significant in assessing the suitability of sites.
5.5.4 The Environment Agency has undertaken pluvial modelling at a national scale and produced
mapping identifying those areas at risk of surface water flooding during 3.33% AEP, 1% AEP
and 0.1% AEP rainfall events. The uFMfSW extents have been made available to NCC as GIS
layers and are illustrated within Figures C1-C13 at Appendix D.
5.5.5 The uFMfSW provides all relevant stakeholders, such as the Environment Agency, NCC as
the LLFA and the public, access to information on surface water flood risk which is consistent
across England and Wales. The modelling will help the Environment Agency take a strategic
overview of flooding, and assist NCC (as the LLFA) in their duties relating to management of
surface water flood risk. For the purposes of this Level 1 Minerals SFRA Update, the mapping
also allows an improved understanding of areas within the County which may have a surface
water flood risk.
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5.6 Groundwater Flooding
5.6.1 Groundwater flooding occurs where groundwater levels rise above ground surface levels. The
local geology is an important factor when assessing the risk of groundwater flooding.
Groundwater flooding is most likely to occur in low-lying areas underlain by permeable rocks
(aquifers), usually associated with chalk, sandstone and limestone catchments that allow
groundwater to rise to the surface through permeable subsoil following long periods of wet
weather.
5.6.2 High water tables may result in standing water on low lying ground that is unable to reach a
ditch or watercourse and is unable to percolate through the ground due to seasonally high
perched groundwater levels.
5.6.3 Minerals workings in most cases excavate below the natural water table, which during periods
of heavy rainfall, may rise. Mineral workings often operate a pumped drainage system and can
therefore interfere with groundwater flow. These issues would be most appropriately
addressed in a site specific FRA at the planning application stage.
5.6.4 Industrial flooding can also occur when pumping ceases and groundwater returns to its natural
level, for example in former mineral workings and urban areas where industrial water
abstraction is reduced from its former rate. Some of this flooding may also be contaminated.
5.6.5 The Environment Agency’s AStGWF map is presented in Figure A-6 at Appendix A.
5.7 Sewer Flooding
5.7.1 Sewer flooding generally results in localised short-term flooding caused by intense rainfall
events overloading the capacity of sewers. Flooding can also occur as a result of blockage,
poor maintenance or structural failure; however this is not included in the STW flooding
records.
5.7.2 Detailed maps provided in Figures D1 to D13 at Appendix D illustrate incidents of internal and
external surface water, foul water and combined sewer flooding for Nottinghamshire.
5.7.3 The DG5 data register provided by STW (Figures D1 to D13 at Appendix D) has recorded a
total of 1923 instances of flooding from overloaded sewers for the whole of Nottinghamshire
since 1980. However no sewer flooding incidents have been recorded within, or within 100m
of, any of the potential mineral sites.
5.7.4 Sewer and surface water flooding are likely to become more frequent and widespread under
urbanisation and climate change scenarios as the amount of impermeable surfaces and runoff
increase, highlighting the importance of SuDS.
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5.8 Artificial Sources – Canals and Reservoirs
5.8.1 Reservoir or canal flooding may occur as a result of the facility being overwhelmed and/or as a
result of dam or bank failure. The latter can happen suddenly resulting in rapidly flowing, deep
water that can cause significant threat to life and major property damage. The Nottingham,
Beeston, Erewash, Grantham and Chesterfield canals are all situated within the Study Area as
illustrated Figure A-1 at Appendix A.
5.8.2 To support this SFRA Update, the C&RT provided records of overtopping and breach events.
A number of overtopping and breach events have previously occurred along the Chesterfield
Canal, as well as the Grantham and Erewash Canals. No historic breach or overtopping
events have been recorded in proximity to the Proposed Allocation Sites.
Nottingham Canal
5.8.3 The Nottingham Canal, opened in 1796, was formerly a 23.6 km long canal stretching
between Langley Mill in Derbyshire and Nottingham. The majority of its length was closed in
1937. The southern section is now part of the River Trent Navigation, and the northern section
is a designated nature reserve. The downstream section of the canal, through Nottingham and
where it connects to the River Trent, remains in use as part of the Beeston and Nottingham
Canal53.
Grantham Canal
5.8.4 The Grantham Canal stretches 53 km from Grantham to West Bridgford via 18 locks where it
joins the River Trent. It was used as a water supply for agriculture, and as such most of the
channel remains in water. Since the 1970s, the Grantham Canal Society has been working
towards its restoration, and two stretches are now navigable to small vessels54.
Erewash Canal
5.8.5 The Erewash Canal starts from the River Trent at Trentlock and proceeds through Long
Eaton. After passing Long Eaton, the canal runs roughly parallel to the River Erewash,
alongside the towns of Sandiacre and Ilkeston, crossing the River Erewash near Eastwood.
The canal ceases at the Langley Mill (Great Northern) basin, where it joins the Nottingham
Canal and the Cromford Canal (both now in a state of abandonment)55.
53 Wikipedia, The free encyclopedia (2011) Nottingham Canal. http://en.wikipedia.org/wiki/Nottingham_Canal 54 Wikipedia, The free encyclopedia (2011) Grantham Canal. http://en.wikipedia.org/wiki/Grantham_Canal 55 Wikipedia, The free encyclopedia (2011) Erewash Canal. http://en.wikipedia.org/wiki/Erewash_Canal
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Chesterfield Canal
5.8.6 The Chesterfield Canal is known locally as 'Cuckoo Dyke'. It was opened in 1777 and ran
74km from the River Trent at West Stockwith in Nottinghamshire through Worksop to
Chesterfield, Derbyshire56. The canal comprises 65 locks and two tunnels, of which one at
Norwood collapsed at the start of the 20th century. As commercial traffic ceased, the lower
reaches were retained and remain popular with pleasure boats. Much of the rest of the canal
has been restored57.
Flooding Mechanisms
5.8.7 Flood risk posed by the canals is at present un-quantified but they can represent as a potential
flood risk.
5.8.8 Canals are considered to be controlled water bodies so flood risk is deemed to be minimal
unless overtopped in storm conditions. There is, however, a residual risk of structural failure.
The C&RT is not a flood defence body, although they do manage some critical flood defence
structures including the Beeston, Sawley and Cranfleet flood gates.
5.8.9 In general, the canal system is hydraulically closed down at relatively low river levels prior to
the issuing of a flood alert from the Environment Agency. This is to protect the canal corridors
from slightly high river levels which would overtop the banks, and to protect craft from
venturing onto rivers at dangerous flows. The system however is dependent on the levels of
associated Environment Agency flood defences. Overtopping or breach of river defences into
the canal corridor could result in transfer of flood waters to other vulnerable areas, for example
problems at Beeston could lead to flooding in Nottingham itself.
5.8.10 Canals generally work at relatively stable water levels with the various lock by-passes, and
waste weirs passing and controlling excess feeds without leading to overtopping of the banks.
5.8.11 The main causes of flooding are likely to be vandalism and a failure of a canal embankment.
This has been known to happen occasionally but the impact is not considered to be as
extensive as a failure of a reservoir dam as studies have shown that maximum discharges are
limited to the volume held within the canal cross section between two locks. This risk is
managed by the C&RT.
56 Wikipedia, The free encyclopedia (2011) Chesterfield Canal. http://en.wikipedia.org/wiki/Chesterfield_Canal 57 British Waterways. Waterscape (2011) Chesterfield Canal. http://www.waterscape.com/canals-and-rivers/chesterfield-canal
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5.8.12 For potential mineral sites located adjacent to a canal, a detailed site specific FRA should be
undertaken to determine the risk of overtopping. For those located adjacent to raised canal
embankments, the detailed site specific FRA should determine the residual risks from
breaching or overtopping as a result of water level control infrastructure failure. If the
development proposals are of a significant scale, consideration should be given to undertaking
a Level 2 SFRA study for that area to determine these residual risks.
Flooding from Reservoirs
5.8.13 From the data provided by the Environment Agency, 79 reservoirs classified under the
Reservoirs Act (1975) (>25,000m3 capacity) are located either within Nottinghamshire or
upstream of the County boundary. These reservoirs are illustrated within Figures D-1 to D-13
of Appendix D.
5.8.14 The Environment Agency’s Risk of Flooding from Reservoirs Mapping58 identifies areas that
could be flooded if a large reservoir were to fail and release the water it holds. The
Environment Agency website should be consulted for further information on risk from
reservoirs:
http://watermaps.environment-
agency.gov.uk/wiyby/wiyby.aspx?&topic=reservoir#x=357683&y=355134&scale=2
Infrastructure Failure
5.8.15 Flooding may result from the failure of engineering installations such as flood defences, land
drainage pumping stations, sluice gates, floodgates and weirs. Hard defences may fail through
the slow deterioration of structural components such as the rusting of sheet piling, erosion of
concrete reinforcement and toe protection or the failure of ground anchors. Such deterioration
is often difficult to detect, so that failure, when it occurs, is often sudden and unexpected.
Failure is more likely when the structure is under maximum stress, such as extreme fluvial
events when pressures on the structure are at its most extreme.
5.8.16 NCC presumes, as a principle, that they are maintained effectively but will consider for each of
them the effect of a catastrophic structural failure resulting in rapid inundation of protected
areas. It is considered that overtopping of such structures during conditions more severe than
for which they have been designed would not itself lead to rapid inundation.
58 Environment Agency (2014) Risk of Flooding from Reservoirs. Accessed: 21/05/14. http://watermaps.environment-agency.gov.uk/wiyby/wiyby.aspx?topic=reservoir#x=528087&y=186344&scale=10
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5.8.17 The Environment Agency’s Areas Benefitting from Flood Defences dataset is presented in
Appendix E, Figures E1-E13. Areas benefitting from the protection of flood defences are at
residual risk from flooding in the event of a breach of the defences.
Redundant Industrial Processes
5.8.18 Operational and redundant industrial processes such as mining, quarrying and sand and
gravel extraction can pose a flood risk when pumping ceases and groundwater returns to its
natural level.
5.8.19 The locations of all existing operational minerals sites are included in the mapping provided in
Appendices A-E.
5.9 Existing Flood Risk Management in Nottinghamshire
5.9.1 The Environment Agency AIMS dataset identifies a significant number of flood defences
throughout the study area, which are classified as fluvial defences. These include major flood
defence assets along the River Trent.
5.9.2 The River Trent defences in Nottinghamshire consist of a range of methods of protection
including embankments, walls and culverts with varying SoPs.
5.10 Flood Warning Areas
5.10.1 Ensuring people in areas of flood risk are aware of potential flooding is key to ensuring they
are prepared, facilitating the protection of property and evacuation where necessary.
5.10.2 The Environment Agency operates a flood warning service for many areas at risk of fluvial and
tidal flooding. The service currently consists of three stages as outlined in Table 5.2.
.
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Table 5-2: Environment Agency Flood Warning Codes Code What it Means? When it is used? What to do?
Flood Alert: Flood is possible. Be prepared.
Two hours to two days in advance of flooding
Be prepared to act on your flood plan.
Prepare a flood kit of essential items.
Monitor local water levels and the flood forecast on the Environment Agency website
Flood Warning: Flooding is expected. Immediate action required.
Half an hour to one day in advance of flooding.
Move staff, stock and valuables to a safe place.
Turn off gas, electricity and water supplies if safe to do so.
Put flood protection equipment in place.
Severe Flood Warning: Severe flooding is expected. There is extreme danger to life and property. Act now!
When flooding poses a significant risk to life.
Stay in a safe place with means of escape.
Be ready should you need to evacuate.
Co-operate with the emergency services.
Call 999 if you are in immediate danger.
Warning no longer in force
Warning no longer in force: No further flooding is currently expected in your area.
When river or sea conditions begin to return to normal.
Be careful. Flood water may still be around for several days.
If you’ve been flooded, ring your insurance company as soon as possible.
5.10.3 All stages of warning are disseminated via Floodline Warnings Direct, which is a free service
that provides warnings to registered customers by telephone, mobile, email, SMS text
message and fax.
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5.10.4 Further information on Flood Warnings in force and Flood Warning Areas can be found from
the Environment Agency website, under Flood Warnings and Midlands Region. The
Environment Agency’s Flood Warning Areas within the Nottinghamshire Study Area are
presented in Appendix A Figure A-7.
5.11 Emergency Planning and Flood Risk
5.11.1 LPAs are classified as Category 1 responders in the context of the CCA. As such their
responsibilities include risk assessment, emergency planning and warning and informing the
public. Emergency Plans are in place in Nottinghamshire. The LPAs work closely with other
Category 1 Responders, such as the Emergency Services, to minimise the impact of flooding.
5.11.2 When dealing with flood risk the multi-agency approach is as follows:
• Preparation – raising flood awareness, ensuring no inappropriate use of the floodplain,
ensuring emergency access and egress routes are available, protecting vital
infrastructure, ensuring adequate flood resilience measures are employed;
• Response – The emergency services would be responsible for rescue operations with
LPAs taking responsibility for providing safe refuge and short term accommodation;
• Recovery – A LPA led Recovery Working Group co-ordinates efforts to provide
support to the community providing longer term temporary accommodation where
appropriate.
5.11.3 NCC has a Flood Response Plan in place, produced by the Local Resilience Forum. The
Flood Response Plan can be requested via NCC’s website.
5.12 Potential Future Minerals Sites and Flood Risk
5.12.1 Appendix F presents flood risk information relating to NCC’s potential future minerals sites in
tabular format, with flood risk in relation to the sites also discussed below.
5.12.2 BGS data illustrates that a large proportion of Nottinghamshire’s sand and gravel deposits
occur in the valley bottom of the Trent and its tributaries and Figure A-2 at Appendix A
illustrates that many of the mineral extraction sites so far identified for potential development
lie wholly or at least partially within Flood Zones 2 and 3. Therefore, these sites are
considered to be at a medium to high risk of fluvial flooding.
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5.12.3 In the absence of a 5% AEP detailed modelled Flood Zone 3b (functional floodplain) outline,
all sites located within Flood Zone 3a are conservatively reclassified as being located within
Flood Zone 3b. Additionally, in the absence of a 1% AEP detailed modelled Flood Zone 3
including an allowance for climate change outline, all sites located within Flood Zone 2 are
conservatively reclassified as being located within Flood Zone 3 plus climate change.
5.12.4 Stockpiles and ancillary buildings can reduce the storage capacity of the floodplain. In
addition, they could alter the natural flow of the flood water by blocking flow paths and
increasing flood risk to adjacent land. Typically in floodplain quarries, sand and gravel
extracted in the spring and summer months is sold directly resulting in small stockpiles.
However, stockpiles are often increased in late summer and autumn to provide sales during
the winter months when pumps are switched off and excavation is inhibited.
5.12.5 This leads to a larger potential impact in the winter months. In order to mitigate this, the
sequential approach should be applied on a site level to ensure that stockpiles and ancillary
offices are located in areas at lowest flood risk to avoid being adversely affected by flooding or
increasing flood risk elsewhere. Site specific FRAs submitted at the application stage can
ensure that sites are designed, worked and restored accordingly.
5.12.6 Flood risk information contained within this Level 1 SFRA Update will form the evidence base
to carry out the Sequential Test for the potential minerals sites. The Sequential Test is a
simple decision-making tool designed to ensure that sites at little or no risk of flooding are
developed in preference to sites at higher risk. Section 7 provides further detail on the
application of the Sequential Test.
5.12.7 The PPG states that where decision-makers have been unable to allocate all proposed
development and infrastructure in accordance with the Sequential Test, taking account of the
flood vulnerability category of the intended use (see Table 7-1 and Table 7-2), it will be
necessary to increase the scope of the SFRA (to a Level 2 SFRA) to provide the information
necessary for application of the Exception Test. A Level 2 would present more detailed flood
risk information for potential mineral sites, such as flood depths and hazard.
5.12.8 Whilst the Sequential Test has not yet been completed by NCC, based on existing and
potential locations available at the time of writing, the following comments can be made
regarding the need for an Exception Test or potential Level 2 SFRA.
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5.12.9 The potential Sherwood Sandstone, gypsum, brick clay and limestone extraction sites
classified as ‘less vulnerable’ developments in the NPPF (see Table 7.1) are predominantly
located within Flood Zone 1 (<=0.1% AEP event) and therefore considered to be at a ‘low risk’
of fluvial flooding. NCC will therefore not be required to apply the Exception Test to these
particular sites and it is not expected that a Level 2 SFRA study will need to be undertaken.
5.12.10 Potential limestone quarry PA38 at Steetley has a watercourse entitled Darfoulds Drain
running through the centre of the site. A small area contained narrowly along the channel is
illustrated as being located within Flood Zones 2 and 3 derived from what appears to be
national broad-scale modelling (i.e. not a detailed model). It is recommended that any
development within this site be limited to within a suitable margin of the extent of the relatively
narrow Flood Zone 2 outline, meaning the site is located wholly within Flood Zone 1 (<=0.1%
AEP). Neither an Exception Test nor a Level 2 SFRA would therefore be considered
necessary for this site.
5.12.11 Sand and gravel sites are often located on low lying ground characteristic of lowland
meandering floodplain deposits where there may be limited surface water drainage due to the
water table being close to the ground surface. Therefore, these may be at increased risk of
surface water and groundwater flooding resulting in standing water and overland flow from
adjacent higher ground. Overland flow paths should therefore be taken into account in spatial
planning for mineral developments.
5.12.12 Such sand and gravel workings are classified as ‘water compatible’ development (Table 7-1 in
Section 7) and it is not expected that an Exception Test will need to be undertaken for such
sites. A Level 2 SFRA however may be required to determine the areas within these flood
zones that pose the least hazard resulting from a combination of flood depth and velocity,
within which to suitably locate the buildings and stockpiles.
5.12.13 The potential minerals sites are generally located in rural areas remote from settlements and
scattered housing, therefore, sewer flooding is not thought to be a significant issue with regard
to flood risk at potential minerals sites.
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6 FLOOD RISK MANAGEMENT MEASURES
6.1 Overview
6.1.1 All new minerals development should have flood risk management factored in at the planning
stage to include the rigorous application of the requirements of the NPPF and PPG with the
use of sustainable flood management measures encouraged where possible. This Chapter
describes how flood risk management can be applied within Nottinghamshire.
6.1.2 Sustainable flood risk management promotes a catchment-wide approach to flooding that
uses natural processes and systems (such as floodplains and wetlands) to slow down and
store water. The use of softer engineering techniques is also promoted as is flood risk
mapping, flood warning, education and emergency response.
6.1.3 Once mineral sites have become redundant, opportunities exist for floodplain creation and
restoration. In addition to flood risk management, a range of opportunities to deliver other
environmental benefits may exist at disused mineral sites, for example biodiversity
improvements such as wetlands and measures to improve water quality to meet WFD
objectives.
6.2 Residual Risk
6.2.1 Residual risks, as defined in the NPPF, are ‘those remaining after applying the sequential
approach and taking mitigating actions’. In a flood risk context, this residual risk pertains to the
flood risk that remains after flood avoidance and alleviation measures have been put in place.
6.2.2 Residual risk management therefore aims to prevent or mitigate the consequences of flooding
that can occur despite the presence of flood alleviation measures.
6.2.3 Application of the Sequential Test aims to preferentially develop or relocate potential
development sites into areas with low flood risk. Where this is not realistically possible, some
development sites may be located in higher flood risk areas, such as Flood Zones 2 and 3. As
a result, such developments will require residual risk management to minimise the
consequences of potential flooding, e.g. following a breach or overtopping of local defences.
6.2.4 Ensuring development is defended to an appropriate design standard reduces flood risk.
However, further options are also available should the residual risk to a development prove
unacceptable.
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6.3 Emergency Planning
6.3.1 A key consideration for any new development is whether adequate flood warning systems and
procedures are in place to ensure that occupants of the site are able to act upon the warnings
and are equipped to take steps to remain safe in the event of a flood.
6.3.2 For sand and gravel workings, the PPG states that any essential ancillary sleeping or
residential accommodation for staff required by the workings will only be permitted in areas of
flood risk subject to a specific warning and evacuation plan.
6.4 Sustainable Flood Risk Management
6.4.1 Traditional flood risk management measures have used hard engineering, the building of flood
walls, embankments and large concrete bridges and culverts. Rivers have been straightened
and floodplains drained to allow for farming and urban development. The result of these
activities is that rivers flow faster and over smaller, more restricted areas than they would
under natural conditions. This restricts the flow of water and can increase flood risk in other
areas of the catchment. Climate change is threatening to make the situation worse so a more
sustainable solution is required.
6.4.2 Once mineral sites have become redundant, opportunities exist for floodplain creation and
restoration.
6.4.3 The Draft Humber River Basin District FRMP23 identifies key flood risks and hazards within the
Humber River Basin and outlines priorities for flood risk management. It should be noted that
the FRMP is currently in draft form and will be revised once consultation responses have been
collated. However the draft FRMP does highlight likely key issues and options within the study
area.
6.4.4 The Idle and Torne Catchment covers the north-west of Nottinghamshire, as well as areas of
North Lincolnshire, Doncaster, Rotherham and Derbyshire. The River Idle Partnership and
Torne Catchment Partnership Forums have been created with the aim of addressing multiple
environmental issues and improving the WFD status of waterbodies. The Forums also look to
enhance flood risk management within the area.. The forums are formed of local councils,
conservation groups, landowners and other stakeholders. The FRMP also identifies the
Bassetlaw Drainage Coordination group, which is a multi-agency partnership focussing on
flood risk issues.
6.4.5 The FRMP identifies the key management issue within the catchment as finding a compromise
between flood risk management and environmental priorities. The Plan outlines a number of
social, economic and environmental objectives for the catchment; however there are currently
no agreed measures for flood risk management.
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6.4.6 The Lower Trent and Erewash Catchment covers the majority of Nottinghamshire. The FRMP
states that a number of measures to prevent risk and prepare for flood risk are currently
ongoing. Measures to prevent risk include looking at the potential to reduce management
costs by changing future maintenance regimes. Measures to reconnect the river with its
floodplain are being investigated, as well as the potential for re-alignment projects and
strategic studies. The FRMP states that a particular focus for the Newark to Gainsborough
area should be to “maximise benefits from disused aggregate workings.”
6.4.7 The Nottinghamshire Biodiversity Action Plan59 outlines the County’s (including Nottingham
City) strategy towards biodiversity and states that opportunities for enhancing biodiversity
include “restoring flooded gravel pits to maximise their value for biodiversity”. There are
opportunities with sustainable flood risk management techniques to enhance or create these
and the following priority habitats; Grazing Marsh/ Wet Grassland, Wetland and Aquatic.
6.5 Restoration of Minerals Sites
6.5.1 Restoration of minerals sites can be designed to reduce flood risk by providing flood storage
and attenuation once extraction of minerals has ceased.
6.5.2 Sand and gravel extraction in a floodplain is likely to create a void that can be used to provide
potential storage during a flood event, generally reducing flow and water levels in the vicinity
of the extraction. Opportunities may also exist to re-position old flood defences in order to
reconnect the floodplain, offering multiple benefits, whilst ensuring that flood risk is not
increased to receptors.
6.5.3 Restoration of minerals sites is likely to be most effective at a strategic (County) scale and is
suggested in PPG. There are potential catchment-scale benefits of carrying out restoration at
numerous disused minerals sites throughout the County.
6.5.4 When restoring minerals sites, opportunities to deliver multiple environmental benefits, such
as enhancements in biodiversity and WFD objectives, should be explored in addition to flood
risk reduction. Areas of open water also provide wildlife benefits and are a method of
sustainable flood management. Water filled mineral extraction sites are valuable stopping off
points for migrating wildfowl. Where marginal vegetation is present they can also provide
nesting sites and a good habitat for invertebrates. In order to explore all potential restoration
options, collaborative working between the site operator, and relevant flood risk, wildlife and
environmental organisations is strongly encouraged.
59 Nottinghamshire Biodiversity action Group (2011) Nottinghamshire Local Biodiversity Action Plan. http://www.nottsbag.org.uk/projects.htm#bap
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6.5.5 NCC has provided the following provisional restoration options detailed in Table 6.1 for their
current potential minerals sites.
Table 6-1: Potential Allocation Mineral Extraction Sites – Potential Restoration Options Proposed Allocation Site Reference
Site Name Mineral Type Area (Ha)
Potential Restoration Options
PA01 Barnby Moor Sand and Gravel 45 Agriculture & Nature
PA02 Bawtry Road, Bryans Close Sand and Gravel 18 Heathland & Grassland
PA03 Besthorpe East Sand and Gravel 24 Water Nature Conservation
PA04 Besthorpe South Sand and Gravel 66 Water
PA05 Bestwood 2 East Sherwood Sandstone 9 Nature Conservation
PA06 Botony Bay Sand and Gravel 113 Agriculture & Wetland
PA07 Bulcote Farm Sand and Gravel 146 Agriculture & Water
PA08 Burridge Farm Sand and Gravel 54 Water Nature Conservation
PA09 Carlton Forest Extention
Sherwood Sandstone 14 Agriculture & Nature
Conservation
PA10 Coddington Sand and Gravel 129 Nature Conservation / Water
PA11 Cromwell South Sand and Gravel 52 Water / Nature Conservation
PA14 East Leake East Sand and Gravel 28 Agriculture Nature Conservation
PA16 East Leake North Sand and Gravel 15 Agriculture & Water
PA17 Flash Farm Sand and Gravel 71 Agriculture & Water
PA18 Foxholes Farm Sand and Gravel 34 Water
PA19 Girton West Sand and Gravel 14 Agriculture & Water
PA20 Holbeck Magnesian Limestone 35 Water & Low Level
Restoration
PA21 Home Farm Sand and Gravel 170 Agriculture
PA22 Langford Quarry East Sand and Gravel 31 Agriculture
PA23 Langford Quarry North Sand and Gravel 31 Water & Nature Conservation
PA24 Langford Quarry South Sand and Gravel 47 Wetland
PA25 Langford Quarry Sand and Gravel 35 Wetland Nature Conservation
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Proposed Allocation Site Reference
Site Name Mineral Type Area (Ha)
Potential Restoration Options
West
PA26 Little Carlton Sand and Gravel 73 Agriculture & Wetland
PA27 Manor Farm Sand and Gravel 151 -
PA28 Nether Langwith West
Magnesian Limestone 31 Water & Nature Conservation
PA29 Red Barn Sherwood Sandstone 13 -
PA31 Scrooby North Sand and Gravel 9 Agricultural Land / Water
PA32 Scrooby South Sand and Gravel 9 Agricultural Land / Water
PA33 Scrooby Top Sherwood Sandstone 20 Agriculture
PA35 Sturton Le Steeple East Sand and gravel 32 Water & Nature Conservation
PA37 Kirton West Brick Clay 25 Water area & Nature Conservation
PA38 Steetley Limestone 20 -
PA38 Finningley Extension Sand and gravel 30 Agricultural Land / Wetland
PA39 Bantycock Extn Gypsum 109 Agriculture
PA40 Shelford East Sand and Gravel 140 Nature Conservation / Water
PA41 Shelford West Sand and Gravel 228 Nature Conservation / Water
PA46 Barton in Fabis Sand and gravel 79 Nature Conservation / Water
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7 NPPF SEQUENTIAL TEST GUIDANCE
7.1 Overview
7.1.1 NCC is required to identify specific deliverable minerals sites to meet their targets and ensure
maintenance of land banks, defined as the minimum quantity of a particular mineral that must
be permitted for extraction at any given time, of at least 7 years for sand and gravel and at
least 10 years for crushed rock. A windfall allowance should only be included where there is
robust evidence of genuine local circumstances that prevent specific sites being identified.
7.1.2 The NPPF states that Local Plans should be supported by an SFRA, and that SFRA’s should
allow a LPA or MPA to steer development towards low flood vulnerability areas by applying
the Sequential Test and, where necessary, the Exception Test.
7.1.3 This Level 1 SFRA Update represents NCCs key document providing the flood risk evidence
base for Nottinghamshire, informing both the upcoming Minerals Local Plan and application of
the Sequential Test. Flood risk information relating to the potential mineral sites is provided in
Appendix F of this SFRA.
7.1.4 The sequential approach is a decision-making tool designed to ensure that sites at little or no
risk of flooding are developed in preference to areas at higher risk in accordance with the
requirements of the NPPF. The test can be applied at all levels and scales of the planning
process, both between and within Flood Zones.
7.1.5 The Sequential Test allows the determination of site allocations based on flood risk and
development vulnerability. Additionally, within each Flood Zone development should be
directed to the areas of least flood risk first, referred to as the sequential approach.
Development should be directed to Flood Zone 1 wherever possible, and then sequentially to
Flood Zones 2 and 3.
7.1.6 The NPPF acknowledges that some areas will be at risk of flooding from flood sources other
than fluvial or tidal systems. All sources of flooding must be considered when looking to locate
new development. Other sources of flooding that require consideration when situating new
development allocations include:
• Flooding from the Land - Surface Water;
• Flooding from Groundwater;
• Flooding from Sewers and Drains; and,
• Flooding from Manmade or Artificial Sources.
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7.1.7 NCC must demonstrate that it has considered a range of possible sites in conjunction with the
flood zone information from the SFRA and the Environment Agency and has applied the
Sequential Test in the mineral site allocation process.
7.1.8 It is acknowledged within the NPPF and PPG that minerals have to be extracted where they
are located but that their operational workings 'should not increase flood risk elsewhere and
need to be designed, worked and restored accordingly'. For this reason sand and gravel
extraction sites are classified as Water Compatible development notwithstanding that such
development can still give rise to flooding problems.
7.1.9 The PPG states that mineral extraction sites often cover large areas, thereby offering the
potential to apply the sequential approach at the site level. Such an approach may allow
ancillary buildings and supporting infrastructure and buildings to be located within areas of a
site at lowest risk from flooding, in order to reduce the risk of being adversely affected by
flooding or increasing flood risk elsewhere.
7.1.10 It should also be noted that essential ancillary sleeping or residential accommodation for staff
required by all Water Compatible development including sand and gravel workings are subject
to a specific flood warning and evacuation plan. NCC should assess whether the requirement
for the mineral could first be met from areas at no risk of flooding and, if not, that there is
justification for the level of development that may ultimately need to take place in areas that
are at risk of flooding.
7.1.11 A flow diagram for the application of the Sequential Test from the PPG is provided in Figure
7.1.
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Figure 7.1: Application of Sequential Test for Plan-Making
7.1.12 The Sequential Test requires an understanding of the flood zones in the study area and the
vulnerability classification of the proposed developments.
7.1.13 Table 7.1 provides a summary of the vulnerability classifications for mineral sites based on
Table 2 of the PPG. Table 7.2 demonstrates which types of mineral development site are
appropriate within each flood zone and where the Exception Test is required.
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Table 7-1: Flood Risk Vulnerability Classification (PPG, 2014)
Development Type Vulnerability Classification
Minerals working and processing (except for sand and gravel working but including Sherwood Sandstone, Limestone, Clay and Gypsum).
Less Vulnerable
Sand and Gravel Working. Essential ancillary sleeping or residential accommodation for staff required by this use, subject to a specific flood warning and evacuation plan.
Water Compatible
Secondary Aggregate Re-cycling Less Vulnerable
Concrete Block Manufacture Less Vulnerable
Concrete Batching Plant Less Vulnerable
Table 7-2: Flood Risk Vulnerability and Flood Zone ‘Compatibility’ (adapted from Planning Practice Guidance, 2014) Flood Risk Vulnerability Classification
Essential Infrastructure
Highly Vulnerable
More Vulnerable
Less Vulnerable
Water Compatible
Floo
d Zo
ne
1
2 Exception Test Required
3a Exception Test Required Exception Test
Required
3b* Exception Test Required† *
- Development is appropriate - Development should not be permitted
† - In Flood Zone 3a essential infrastructure should be designed and constructed to remain operational and safe in times of flood.
* - In Flood Zone 3b (functional floodplain) essential infrastructure that has to be there and has passed the Exception Test, and water-compatible uses, should be designed and constructed to:
• Remain operational and safe for users in times of flood;
• Result in no net loss of floodplain storage;
• Not impede water flows and not increase flood risk elsewhere.
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7.1.14 Table 7-1 and Table 7.2 demonstrate that mineral developments are classified as either Water
Compatible or Less Vulnerable development and as such are permitted within Flood Zone 1,
Flood Zone 2 and Flood Zone 3a, subject to the satisfaction of the Sequential Test. Table 7.2
confirms that the Exception Test is not usually applicable to minerals development sites due to
their vulnerability classification; however any essential ancillary sleeping or residential
accommodation for staff required by Water Compatible development, such as sand and gravel
workings, are subject to a specific flood warning and evacuation plan.
7.1.15 Any proposed development on a windfall site will by definition differ to a site allocated in the
Minerals Local Plan that has been sequentially tested. Therefore, the Sequential Test will
need to be applied at the planning application stage and should be subject to the same
consideration of flood risk as other development sites.
7.1.16 Where a flood source other than tidal and fluvial is identified that does not affect the ability of a
site to pass the Sequential Test, a site specific FRA should still be completed to assess the full
impacts of flooding to the site from all sources. i.e. a site may be located in Flood Zone 1 and
be considered to pass the Sequential Test but still be at risk from surface water or
groundwater flooding which should be fully investigated in a site specific FRA.
7.1.17 The maps presented in Appendix A to Appendix E are designed to assist NCC in determining
the flood risk classification for each site and in completing the Sequential Test. This will aid the
determination of the most suitable type of land use at each site based on the vulnerability and
flood risk.
7.1.18 The spatial strategy for minerals development is primarily driven by geology as minerals can
only be worked where they naturally occur. This has implications when carrying out the
Sequential Test in accordance with the NPPF (steering development to lowest flood risk) as
reasonable alternative sites may not always be available. This is particularly the case with
deposits of sand and gravel as many of the deposits are located within natural river floodplains
which are often inundated during flood events, therefore not 'preferred' in accordance with the
Sequential Test.
7.2 Using the SFRA Maps, Data and GIS Layers
7.2.1 Table 7.3 highlights which GIS layers and SFRA data should be used in carrying out the
Sequential Test. The table poses some example questions which provide some guidance in
where to look within the SFRA for the information.
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Table 7-3: Sequential Test Key - A Guide to using the SFRA GIS Layers Category GIS Layer & Figure Example Questions
Dev
elop
men
t Vu
lner
abili
ty
Not applicable refer to Table 2 in PPG
Question 1 - Is the proposed development defined as ‘More Vulnerable’ according to Table 2 of PPG?
Question 2 - Is the proposed development defined as ‘Less Vulnerable’ according to Table 2 of PPG?
Question 3 - Is the proposed development defined as ‘Water Compatible development’ according to Table 2 of PPG?
Floo
d Zo
ne C
lass
ifica
tion
Environment Agency main river maps. Question 4 - Is the site located near a watercourse?
SFRA fluvial FZ2, FZ3a & FZ3b layers. Also examine historical floodplain and take into consideration climate change outlines. See Figures 3.0 – 3.7 in Appendix B.
Question 5 – Through consultation of the Environment Agency’s Flood Zone maps, is the development site located in Flood Zone 1?
Question 6 - Through consultation of the Environment Agency’s Flood Zone maps, is the development site located in Flood Zone 2?
Question 7 - Through consultation of the Environment Agency’s Flood Zone maps, is the development site located in Flood Zone 3a?
Question 8 - Through consultation of the Environment Agency’s Flood Zone maps, is the development site located in Flood Zone 3b?
Question 9 - Can the development be located in Flood Zone 1?
Question 10 - Can the development be located in Flood Zone 2?
Question 11 - Can the development be located in Flood Zone 3a?
Oth
er F
lood
Sou
rces
SFRA fluvial FZ2 & FZ3 outlines plus climate change
Question 12 – Is the site impacted by the effects of climate change
Sewer Flood Layer & Historical Flood Outlines
Question 13 - Is the site in an area potentially at risk from sewer flooding?
uFMfSW, historical Flood Outlines, groundwater vulnerability maps
Question 14 - Is the site in an area potentially at risk from overland flow flooding?
Question 15 - Is the site located in an area of rising groundwater levels?
Question 16 - Does the site have a history of flooding from any other source?
Floo
d R
isk
Man
agem
ent Flood Defence Layer
(AIMS), Flood Warning Layer, Areas Benefiting from Flood Defences Layer
Question 17 - Does the site benefit from flood risk management measures?
Question 18 - Can the development be relocated to an area benefiting from flood risk management measures or of lower flood risk?
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7.3 How to apply the Sequential Test where there are gaps in data
7.3.1 It should be noted that some watercourses in the study area do not have flood zones
associated with them or do not have all flood zones defined. This is not to suggest these
watercourses do not flood, moreover that modelled data is not currently available. Therefore,
allocations adjacent to watercourses where flood zones have not been defined cannot be
assessed against all aspects of the Sequential Test using the existing data.
7.3.2 To overcome gaps in existing data and to enable NCC to proceed with application of the
Sequential Test the following criteria should be considered:
• For watercourses where no flood zones have been defined:
– For application of the Sequential Test, the site should be considered as lying
within Flood Zone 3a until proven otherwise.
– If a site is within 8m of a watercourse and promoted for development, further
investigation should be undertaken to determine the suitability of the site for the
proposed development.
– If, following further investigation, the site is found to lie within Flood Zone 3b the
development may not be appropriate against the policies presented in the NPPF;
• For watercourses where Flood Zone 3b (functional floodplain) has not been defined:
– If a proposed development site is located in Flood Zone 3a, there is a possibility
it may also fall within Flood Zone 3b. Further investigation should be undertaken
to define Flood Zone 3b for the local watercourse(s).
– According to the NPPF, when applying the Sequential Test the site should be
considered as lying within Flood Zone 3b until proven otherwise.
– If, following further investigation, the site is found to lie within Flood Zone 3b the
development may not be appropriate against the polices presented in the NPPF;
• For watercourses where the effect of climate change on flood zones has not been
defined:
– For any development located in or adjacent to a flood zone boundary, there is a
possibility that when considering the effects of climate change the site may be at
greater flood risk. For example if a site is clearly identified to be located in Flood
Zone 2 (present day), when the effects of climate change are considered the site
may be found to lie within Flood Zone 3.
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– For application of the Sequential Test sites located in Flood Zone 3 or at the
boundary of Flood Zone 2 and 3, where the effects of climate change are not
defined, the sites can be considered to lie within the higher risk flood zone.
However, the effects of climate change should be investigated further as part of a
site specific FRA.
– If following further investigation the site is found to lie within a different flood
zone, the Sequential Test should be re-applied to determine if the proposed
development is appropriate.
7.4 The Exception Test
7.4.1 The purpose of the Exception Test is to ensure that new development is only permitted in
Flood Zone 2 and Flood Zone 3 where flood risk is clearly outweighed by other sustainability
factors and where the development will be safe during its lifetime, considering climate change.
7.4.2 The NPPF states that for the Exception Test to be passed:
• It must be demonstrated that the development provides wider sustainability benefits to
the community that outweigh flood risk, informed by the SFRA where one has been
prepared; and
• A site-specific Flood Risk Assessment must demonstrate that the development will be
safe for its lifetime taking account of the vulnerability of its users, without increasing
flood risk elsewhere, and, where possible, will reduce flood risk overall.
7.4.3 Both elements of the test will have to be passed for development to be allocated or permitted.
7.4.4 Whilst it is acknowledged that the Exception Test is not usually applicable to minerals
development sites due to their vulnerability classification, a final decision on whether the
Exception Test is required should be taken following application of the Sequential Test.
7.4.5 A flow diagram for application of the Exception Test from the PPG is provided in Figure 7.2:
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Figure 7.2: Guidance on the application of the Exception Test
7.5 What is a Level 2 SFRA?
7.5.1 Where decision makers have been unable to allocate all potential future minerals sites and
infrastructure in accordance with the Sequential Test using the Level 1 SFRA, it will be
necessary to increase the scope of the SFRA to provide the information necessary for
application of the Exception Test.
7.5.2 A Level 2 SFRA will assess the nature of the flood risk in more detail to include hazard and
depth mapping including the presence of flood defence measures. This will allow a sequential
approach to development within the flood zone, as areas with lower hazard and depth can be
highlighted and developed ahead of areas at higher risk with regard to hazard and depth of
water.
7.5.3 The PPG also states that:
7.5.4 “A Level 2 Strategic Flood Risk Assessment should also reduce burdens on developers, in
particular, at windfall sites, in preparation of site-specific flood risk assessments,”
7.5.5 It may be the case that whilst the Exception Test is not required for the potential minerals
sites, due to the location of a number of sites in Flood Zones further detailed modelling may be
required to define flood risk as part of a site-specific FRA.
7.5.6 Discussion within the Council as to the requirement for a Level 2 SFRA is currently ongoing.
Where sites require detailed flood risk modelling, this may be delivered within a Level 2 SFRA,
or required as part of the planning application process.
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8 SITE SPECIFIC FLOOD RISK ASSESSMENT GUIDANCE
8.1 Introduction
8.1.1 This Level 1 SFRA for NCC provides a high level assessment of the flood risk posed to the
area. However, this document has a strategic scope and therefore it is essential that site-
specific FRAs are also developed for individual development proposals and that where
necessary and appropriate, suitable mitigation measures are incorporated.
8.1.2 This section presents recommendations and guidance for site-specific FRAs prepared for
submission with planning applications for mineral sites in Nottinghamshire.
8.2 When is a Flood Risk Assessment required?
8.2.1 The NPPF states that a site-specific FRA is required in the following circumstances:
• For proposals of 1 hectare or greater in Flood Zone 1;
• All proposals for new development (including minor development and change of use)
in Flood Zone 2 and Flood Zone 3, or in an area within Flood Zone 1 which has critical
drainage problems (as notified to the LPA by the Environment Agency); and,
• Where proposed development or a change of use to a more vulnerable class may be
subject to other sources of flooding.
8.2.2 A FRA should be proportionate to the degree of flood risk as well as the scale, nature and
location of the proposed development.
8.2.3 All of the minerals sites that have been assessed in this SFRA are greater than 1 hectare in
site area and would therefore require a site-specific FRA.
8.2.4 The Environment Agency Guidance Note for FRAs in Flood Zone 160
(https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311502/LIT_91
93.pdf) should be consulted for advice on the approach and content of a FRA.
8.3 Scope of a Site-Specific Flood Risk Assessment
8.3.1 The NPPF and PPG states that site-specific FRAs should always be proportionate to the
degree of flood risk and make optimum use of readily available information, for example the
mapping presented within this SFRA.
8.3.2 The PPG states the objectives of a site-specific FRA are to establish:
• Whether a proposed development is likely to be affected by current or future flooding 60 Environment Agency (April 2012) Flood Risk Assessment (FRA) Guidance Note 1 (https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/311502/LIT_9193.pdf
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from any source;
• Whether a proposed development will increase flood risk elsewhere;
• Whether the measures proposed to deal with these effects and risks are appropriate;
• The evidence for the local planning authority to apply (if necessary) the Sequential
Test, and;
• Whether the development will be safe and pass the Exception Test, if applicable.
8.3.3 Table 8.1 is based on the checklist for site specific FRAs provided in the PPG. Where
appropriate, references have been added to determine where the information can be found
within the SFRA to support each required item.
Table 8-1: Site-Specific Flood Risk Assessment Checklist (Planning Practice Guidance) 1. Development description and location
1a. What type of development is proposed (e.g., new development, an extension to existing development, a change of use etc.) and where will it be located?
1b. What is its flood risk vulnerability classification?
Refer to Section 7.1 Table 7.1.
1c. Is the proposed development consistent with the Local Plan for the area?
NCC is currently carrying out a review of the Minerals Local Plan and is due to publish its Draft Minerals Local Plan in 2015.
1d. What evidence can be provided that the Sequential Test and where necessary the Exception Test has/have been applied in the selection of this site for this development type?
1e. Will your proposal increase overall the number of occupants and/or users of the building/land, or the nature or times of occupation or use, such that it may affect the degree of flood risk to these people?
This is particularly relevant to minor developments (alterations & extensions) & changes of use.
2. Definition of the flood hazard
2a. What sources of flooding could affect the site?
Refer to Section 5
2b. For each identified source under 2a above, can you describe how flooding would occur, with reference to any historic records where these are available?
Refer to Section 5
2c. What are the existing surface water drainage arrangements for the site?
Undertake a site survey to determine specific details. Where appropriate an asset location survey can be provided by Severn Trent Water at http://www.stwater.co.uk/developers/request-a-water/sewer-map/.
3. Probability
3a. Which flood zone is the site within?
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3b. Does the SFRA show the same or a different flood zone compared with the Environment Agency’s flood map?
The Flood Map for Planning (Rivers and Sea) is available on the Environment Agency’s website http://maps.environment-agency.gov.uk/wiyby. If different you should seek advice from the local planning authority and, if necessary, the Environment Agency enquiries@environment-agency.gov.uk.
3c. What is the probability of the site flooding, taking account of the maps of flood risk from rivers and the s and from surface water, on the Environment Agency’s website, and the SFRA, and of any further flood risk information for the site?
Refer to mapping in Appendices B and C, as well as the Flood Map for Planning (Rivers and Sea) and the Flood Risk from Surface Water mapping on the Environment Agency’s website http://maps.environment-agency.gov.uk/wiyby.
3d. If known, what (approximately) are the existing rates and volumes of surface water run-off generated by the site?
4. Climate change
How is flood risk at the site likely to be affected by climate change?
Refer to Section 4.7 for a description of how climate change will impact sources of flooding.
5. Detailed development proposals
Where appropriate, are you able to demonstrate how land uses most sensitive to flood damage have been placed in areas within the site that are at least risk of flooding (including providing details of the development layout)?
Refer to Section 7 regarding the use of the sequential approach within development sites.
6. Flood risk management measures
How will the site/building be protected from flooding, including the potential impacts of climate change, over the development’s lifetime?
Refer to Section 6 for details regarding flood risk management measures.
7. Off-site impacts
7a. How will you ensure that your proposed development and the measures to protect your site from flooding will not increase flood risk elsewhere?
7b. How will you prevent run-off from the completed development causing an impact elsewhere?
7c. Are there any opportunities offered by the development to reduce flood risk elsewhere?
Refer to guidance regarding surface water management and SuDS
8. Residual risks
8a. What flood-related risks will remain after you have implemented the measures to protect the site from flooding?
8b. How, and by whom, will these risks be managed over the lifetime of the development? (E.g., flood warning and evacuation procedures).
8.3.4 The requirement to undertake a site specific FRA to support applications for development
proposed in flood risk areas or where proposed development may increase flood risk to third
parties still applies under the NPPF.
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8.3.5 The NPPF states that site-specific FRAs should be carried out to the appropriate degree, at all
levels of the planning process and to inform the application of the sequential approach. They
should assess the risks of all forms of flooding to and from development, taking climate
change into account.
8.3.6 It is the responsibility of applicants to consider the flood risk to a site as early as possible.
Applicants should refer to the SFRA at the start of the pre-application stage, or if this is not
carried out, at the earliest stage in the preparation of development proposals and a planning
application.
8.3.7 The preparation of this SFRA does not remove the need for site-specific FRAs to be
undertaken to support planning applications. A site-specific FRA will need to demonstrate that
flood risk to the development can be managed now and over the lifetime of the development
for all sources of flooding. It should show that the development is safe.
8.3.8 A site-specific FRA should demonstrate also that the development does not increase the risk
of flooding to third parties from all sources and that the proposals are compliant with local
planning policy. Where possible the development should aim to reduce flood risk overall, and
the site-specific FRA should demonstrate this where it is the case.
8.4 Sequential Approach within Development Sites
8.4.1 Flood risk should be considered at an early stage in deciding the layout and design of a site to
provide an opportunity to reduce flood risk within the development.
8.4.2 The sequential approach should be applied within development sites to locate the most
vulnerable elements of a development in the lowest risk areas. The PPG acknowledges that
minerals sites tend to cover large areas, which may provide the opportunity to locate ancillary
facilities and buildings in areas at lowest risk from flooding.
8.4.3 Should development pressure create a need to develop more vulnerable land uses within the
site in higher flood risk areas appropriate mitigation measures should be incorporated that are
proportionate to the flood risk and would not increase the risk of flooding to surrounding areas.
8.4.4 Structures located in areas with a high flood risk should be flood resilient.
8.5 Surface Water Management
8.5.1 The NPPF requires the use of SuDS as an opportunity for managing flood risk, improving
water quality and increasing amenity and biodiversity.
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8.5.2 The NPPF states that flood risk should not be increased elsewhere as a result of development
and therefore surface water runoff leaving a site should not increase from existing rates. The
PPG states that this should be applicable over the lifetime of the development, allowing for
climate change. As per the NPPF, PPG and Environment Agency Standing Advice ‘Climate
change allowances for planners’ peak rates of surface water runoff should not exceed existing
rates up to and including the 1 in 100 year storm with an allowance for climate change.
8.6 Residual Risk
8.6.1 The NPPF states that the residual risks of flooding should be identified as part of a FRA, and it
should be demonstrated how this residual risk would be safely managed. Like other parts of
the FRA the assessment should be proportionate to the scale of the development and the
risks involved. This SFRA provides a starting point for obtaining information on the residual
risk (see locations of raised fluvial flood defences in Appendix B).
8.6.2 As with all aspects of development and flood risk, this is best considered early in the
development process so that measures to manage residual risk can be incorporated into site
layout to make the best use of the developable land.
8.6.3 Measures to manage residual flood risk include:
• Developer contributions towards publicly-funded flood alleviation schemes;
• Flood resilience and resistance measures;
• Flood warning and evacuation plans; and
• Designing new SuDS taking account of storm events which exceed the design
standard.
8.7 Summary
8.7.1 To achieve the aims of the NPPF with regard to site-specific FRAs, NCC should:
• Ensure the Sequential Test is undertaken for all occasions and windfall sites promoted
for development within their administrative areas;
• Have regard to the vulnerability classification of developments and local emergency
planning issues when determining suitable locations for minerals development sites;
• Have regard to the cumulative impact of development on flood risk; In Flood Zone 2
and Flood Zone 3 the mapped/known risk of flooding comes from either rivers or the
sea. In these areas the impact of minor developments on flooding by causing flood
levels to rise is usually small. In some circumstances however, the cumulative effect of
many minor developments in the same area can have a serious impact and must
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therefore be considered. It should be noted that minerals sites typically cover a large
area and therefore the cumulative impact may be considerable;
• Determine decisions for windfall development through application of the Sequential
Test. Where this is not practical NCC should balance the flood risk at an individual
site, the type of development proposed, including the proposed mineral to be
extracted, emergency planning and the contribution the development would make to
the wider sustainability of the area before determining a decision;
• Consider flood risk as one of a number of policies that in tandem can provide
mechanisms to deliver sustainable developments with multiple benefits;
• Engage with developers and local regulators throughout the development process to
develop and instigate initiatives for the reduction of flood risk;
• Require site-specific FRAs in accordance with NPPF guidelines.
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9 SUSTAINABLE DRAINAGE SYSTEMS
9.1.1 An overview of SuDS and why they should be used is included below.
9.1.2 Dewatering and pumping during mineral extraction will require the use of appropriate SuDS
techniques to ensure that the risk of flooding in the surrounding area is not increased and
where possible is reduced.
9.1.3 The construction of any ancillary buildings and paved areas as part of the mineral sites will
also need to comply with the requirements for surface water management and be addressed
as part of the site-specific FRA.
9.1.4 Site promoters should consult with the Environment Agency, LPAs and NCC about their
proposals for surface water management and site drainage through the use of SuDS to ensure
that they are adopting the most effective methods for their site.
9.1.5 NCC, as LLFA for Nottinghamshire, is a statutory consultee for planning applications for major
developments that have a drainage implication. As outlined in Section 3.3.6, NCC will be
under a duty to respond to the LPA and report on their performance on providing a substantive
response within deadlines set out in legislation.
9.2 What are SuDS?
9.2.1 SuDS are typically softer engineering solutions inspired by natural drainage processes such
as ponds and swales which manage water as close to its source as possible. Wherever
possible, a SuDS technique should seek to contribute to each of the three goals identified
below with the preferred system contributing significantly to each objective. Where possible
SuDS solutions for a site should seek to:
1. Reduce flood risk (to the site and neighbouring areas);
2. Reduce pollution; and,
3. Provide landscape and wildlife benefits.
9.2.2 These goals can be achieved by utilising a management plan incorporating a chain of
techniques, as outlined in the Interim Code of Practice for Sustainable Drainage Systems61,
where each component adds to the performance of the whole system:
• Prevention: Good site design and upkeep to prevent runoff and pollution (e.g. limited
paved areas, regular pavement sweeping);
• Source Control: Runoff control at/near to source (e.g. rainwater harvesting, green
roofs, pervious pavements);
61 Defra (July 2004). National SUDS working group. Interim Code of Practice for Sustainable Drainage Systems
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• Site Control: Water management from a multitude of catchments (e.g. route water
from roofs, impermeable paved areas to one infiltration/holding site);
• Regional Control: Integrate runoff management systems from a number of sites (e.g.
into a detention pond).
9.2.3 The application of SuDS is not limited to a single technique per site. Often a successful SuDS
solution will utilise a combination of techniques, providing flood risk, pollution and
landscape/wildlife benefits. In addition, SuDS can be employed on a strategic scale, for
example with a number of sites contributing to large scale jointly funded and managed SuDS.
It should be noted that each development site must offset its own increase in runoff and
attenuation cannot be "traded" between developments.
9.2.4 SuDS techniques can be used to reduce the rate and volume and improve the water quality of
surface water discharges from sites to the receiving environment (i.e. natural watercourse or
public sewer etc.), which is of particular importance for mineral sites. Various SuDS
techniques are available and operate on two main principles:
• Infiltration;
• Attenuation.
9.2.5 All systems generally fall into one of these two categories, or a combination of the two.
9.2.6 As part of any SuDS scheme, consideration should be given to the long-term maintenance of
the SuDS to ensure that it remains functional for the lifetime of the development.
9.2.7 Table 9.1 has been reproduced from the SuDS Manual, CIRIA C67962 and outlines typical
SuDS options and details their typical components.
62 CIRIA (2008) Invasive Species Management for Infrastructure Managers and the Construction Industry (C679)
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Table 9-1: Typical SuDS Components (Y = primary process. * = some opportunities, subject to design)
Technique Description
Con
veya
nce
Det
entio
n
Infil
trat
ion
Har
vest
ing
Pervious Surfaces
Pervious surfaces allow rainwater to infiltrate through the surface into an underlying storage layer, where water is stored before infiltration to the ground, reuse, or release to surface water.
Y Y *
Filter Drains
Linear drains/trenches filled with a permeable material, often with perforated pipe in the base of the trench. Surface water from the edge of paved areas flows into the trenches, is filtered and conveyed to other parts of the site.
Y Y
Filter Strips Vegetated strips of gently sloping ground designed to drain water evenly from impermeable areas and filter out silt and particulates.
* * *
Swales Shallow vegetated channels that conduct and/or retain water, and can permit infiltration when unlined. Y Y *
Ponds Depressions used for storing and treating water. Y * Y
Wetlands
As ponds, but the runoff flows slowly but continuously through aquatic vegetation that attenuates and filters the flow. Shallower than ponds. Based on geology these measures can also incorporate some degree of infiltration.
* Y * Y
Detention Basin Dry depressions designed to store water for a specified retention time. Y
Soakaways Sub-surface structures that store and dispose of water via infiltration. Y
Infiltration Trenches
As filter drains, but allowing infiltration through trench base and sides. * Y Y
Infiltration Basins Depressions that store and dispose of water via infiltration. Y Y
Green Roofs
Green roofs are systems which cover a building’s roof with vegetation. They are laid over a drainage layer, with other layers providing protection, waterproofing and insulation. It is noted that the use of brown/green roofs should be for betterment purposes and not to be counted towards the provision of on-site storage for surface water. This is because the hydraulic performance during extreme events is similar to a standard roof (CIRIA C697).
Y
Rainwater Harvesting
Storage and use of rainwater for non-potable uses within a building, e.g. toilet flushing. It is noted that storage in these types of systems is not usually considered to count towards the provision of on-site storage for surface water balancing because, given the sporadic nature of the use of harvested water, it cannot be guaranteed that the tanks are available to provide sufficient attenuation for the storm event.
* * * Y
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9.3 Why use SuDS?
9.3.1 Traditionally, built developments have utilised piped drainage systems to manage storm water
and convey surface water run-off away from developed areas as quickly as possible. Typically,
these systems connect to the public sewer system for treatment and/or disposal to local
watercourses. Whilst this approach rapidly transfers storm water from developed areas, the
alteration of natural drainage processes can potentially impact on downstream areas by
increasing flood risk, reduction in water quality, loss of water resource and detriment to
wildlife. Therefore, receiving watercourses have greater sensitivity to rainfall intensity, volume
and catchment land uses post development.
9.3.2 Certain measures can be taken to protect more sensitive areas by reducing or prohibiting
infiltration. In marginal areas where polluted water may have an impact on the groundwater,
runoff can pass through one or more treatment stages depending on the potential level of
pollution and hydro-geological conditions. If all infiltration was prohibited it is likely that a SuDS
attenuation system would still represent an improved system over a traditional piped system
enabling an improvement to the quality of the surface water runoff.
9.3.3 Current planning policy outlines that runoff rates post development must not exceed the
existing (pre-development) rates. In addition, opportunities should be sought to achieve
Greenfield runoff rates.
9.4 The SuDS hierarchy
9.4.1 The National Standards for sustainable drainage systems63 states that “the following
destinations must be considered for surface runoff in order of preference”:
1. Discharge into the ground;
2. Discharge to a surface water body;
3. Discharge to a surface water sewer;
4. Discharge to a combined sewer.”
9.5 Infiltration SuDS
9.5.1 The underlying ground conditions of a development site will often determine the type of SuDS
approach to be used at development sites. In the design of any drainage system and SuDS
approach, consideration should be given to site-specific characteristics and where possible be
based on primary data from site investigations.
63 Defra, December (2011) National Standards for sustainable drainage systems https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/82421/suds-consult-annexa-national-standards-111221.pdf
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9.5.2 Infiltration SuDS rely on discharges to ground, where ground conditions are suitable.
Therefore, infiltration SuDS are reliant on the local ground conditions (i.e. permeability of soils
and geology, the groundwater table depth and the importance of underlying aquifers as a
potable resource) for their successful operation.
9.5.3 Various infiltration SuDS techniques are available for directing the surface water run-off to
ground. Development pressures and maximisation of the developable area may reduce the
area available for infiltration systems but this should not be a limiting factor for the use of
SuDS.
9.5.4 Either sufficient area is required for infiltration or a combined approach with attenuation could
be used to manage surface water runoff. Attenuation storage may be provided in the sub-base
of a permeable surface, within the chamber of a soakaway or as a pond/water feature.
9.5.5 Infiltration measures include the use of permeable surfaces and other systems that are
generally located below ground.
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APPENDIX A – FIGURES A1-A8 Figure A-1 – Study Area, Main Watercourses & Minerals Sites Figure A-2 – Environment Agency Flood Zones (Undefended) Figure A-3 – Internal Drainage Board Areas Figure A-4 – Groundwater Source Protection Zones Figure A-5a – Environment Agency Bedrock Aquifer Designations Figure A-5b – Environment Agency Bedrock and Superficial Deposits Aquifer Designations Figure A-6 – Areas Susceptible to Groundwater Flooding Figure A-7 – Flood Warning Areas Figure A-8 – Worked Out and Existing Mineral Sites
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APPENDIX B – FIGURES B1-B13 Figures B1-B13 – Fluvial (River) Flooding
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APPENDIX C – FIGURES C1-C13 Figures C1-C13 – Pluvial (Surface Water) Flooding
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APPENDIX D – FIGURES D1-D13 Figures D1-D13 – Other Potential Sources of Flooding and Historical Flooding
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APPENDIX E – FIGURES E1-E13 Figures E1-E13 – Detailed Modelled Flood Outlines (Defended)
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APPENDIX F – POTENTIAL MINERALS SITES
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APPENDIX G – DATA REGISTER
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