isle of wight level 2 sfra (2018) · 2018-11-30 · sfra when the level 2 sfra is making...

Isle of Wight Level 2 SFRA (2018)

DRAFT

Wood Environment & Infrastructure Solutions UK Limited – October 2018

2 © Wood Environment & Infrastructure Solutions UK Limited

Draft - see disclaimer

October 2018

Doc Ref. 41017-C005-Draft IoW Level 2 SFRA

Report for

Chris Mills

Planning Policy

Seaclose Offices

Fairlee Road

Newport

Isle of Wight

PO30 2QS

Main contributors

Sam Bray

Ben Thomas

Peter Duffel

Issued by

Sam Bray

.................................................................................

Approved by

John Rampley-Clarke

.................................................................................

Wood

12th Floor, 25 Canada Square,

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United Kingdom


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1 Draft for comment 26-10-18


October 2018


Contents

1. Introduction 5

1.1 Scope of the Level 2 SFRA 5

1.2 Flood Risk and Planning Policy 6

1.3 Isle of Wight Level 2 SFRA Context 7 Level 1 SFRA 7 Level 2 SFRA 7

1.4 SHLAA process – Selection of the 14 Level 2 SFRA Sites 7

2. Level 2 Site Assessments 9

2.1 Sources of information 9

2.2 SFRA Level 2 Approach 9 Overview 9 Level 2 Factsheet Structure 10

3. Supporting the Application of the Exception Test 12

3.1 The Exception Test 12 Application of the Exception Test 13 Passing the Exception Test 13

3.2 Allowing for Climate Change 13 Climate Change and River Flows 13 Climate Change and Peak Rainfall Intensity 16 Climate Change and Sea Level Rise 16

3.3 Site-Specific Flood Risk Assessments 16 Use of SuDS 17

Table 1.1 Sites for Assessment in Level 2 SFRA 8 Table 2.1 SHLAA Site-Specific Assessment Factsheet locations 9 Table 3.1 Flood Risk Vulnerability and Flood Zone ‘Compatibility’ 12 Table 3.2 South East River Basin District – Peak River Flow Allowances (using a 1961 to 190 baseline) 14 Table 3.3 Flood Risk Vulnerability Classifications 14 Table 3.4 Application of Peak River Flow Uplifts Based on Flood Zone and Development Vulnerability 15 Table 3.5 Peak Rainfall Intensity Allowance in Small and Urban Catchments (use 1961 to 1990 baseline) 16

Appendix A IPS027 - Former Flamingo Park, Oakhill Road, Seaview Appendix B IPS035 - Green Gate Industrial Estate, Thetis Road, Cowes Appendix C IPS055 - 6-8 George Street, Ryde Appendix D IPS077 - Former Sandham Middle School Site, Perowne Way, Sandown Appendix E IPS078 - Test Centre site, 23 Medina Avenue, Newport Appendix F IPS117 – Land rear of High Street, Whitwell Appendix G IPS135/217 - Land north of Perowne Way Appendix H IPS138B - Land on the south-west side of Buckbury Lane, Newport Appendix I IPS150 - Westridge Cross Dairy and land to the north of Bullen Road, Ryde Appendix J IPS215 - Manor Farm (West Field), Wellow


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Appendix K IPS342 - Land off Gunville Road, (west) Newport Appendix L IPS350 - Buildings at Lee Farm, Wellow Appendix M IPS371 – Newport Harbour


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1. Introduction

This section of the report describes the scope of the Level 2 SFRA, the organisation of the

data in the Level 2 SFRA and directs the reader to the relevant sections and appendices,

according to the needs of the reader.

1.1 Scope of the Level 2 SFRA

National planning policy is set out in the NPPF1, published by the Government in 2012 and revised in 20182.

The NPPF is accompanied by online Planning Practice Guidance (PPG), published in 20143, which provides

further guidance on specific issues such as flood risk. The NPPF and NPPG supersedes PPS25 and its

associated planning practice guidance. The scope of the Isle of Wight Level 2 SFRA has been aligned to meet

the specific requirements of the Isle of Wight Council as established in 2018 and it is guided by the guidance

provided in the PPG.

The Isle of Wight Council has performed a rigorous and stringent application of the Sequential Test using the

2010 SFRA. The Sequential Test has been carried out by the Council alongside other site suitability

assessments to identify which of the SHLAA (Strategic Housing Land Availability Assessment) sites should be

progressed to site allocation. The application of the Sequential Test resulted in sites identified as being

wholly or partially within a zone of flood risk being discounted. The exception to this rule is where the sites

were in brownfield areas and/or regeneration areas. Under these exceptional circumstances the sites have

been ‘tagged’ for consideration as part this more detailed Level 2 assessment.

Within a Level 2 SFRA the PPG advocates the need to assess the flood risks associated with flood defence

failure in areas benefitting from defences, and to quantify flood hazards in terms of velocities, depths, rates

of onset and duration. The quantification of flood hazards in this way requires detailed hydraulic modelling

to be undertaken, to inform the recommendations for safe and sustainable development which adequately

manages future increases in risk owing to climate change. This additional detail is only required in a Level 2

SFRA when the Level 2 SFRA is making recommendations for safe development in the areas of flood risk. The

scope of this Level 2 SFRA excludes additional hydraulic modelling as the SFRA only provides

recommendations for safe development by developing areas outside of zones of tidal and fluvial flood risk.

Where the Level 2 SFRA cannot recommend safe development of a site, through the principle of avoidance,

the site has not been identified as being suitable for residential development without further site-specific

assessment.

The Structure of the Level 2 SFRA is as follows:

Section 1 – Introductory Section describing the scope of the assessment, provides an

outline of the context of the Level 1 AND Level 2 SFRA and describes the origin of the 14

SHLAA sites in the SFRA

Section 2 – Describes the Level 2 assessment process, the sources of information

underpinning the assessment and the structure and form of the Factsheets in Appendices A

to M.

1 Department for Communities and Local Government, 2012. National Planning Policy Framework, published March 2012.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf 2 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/740441/National_Planning_Policy_Framework_web_accessible_version.pdf 3 https://www.gov.uk/government/collections/planning-practice-guidance

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf


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Section 3 – Provides a summary of the Level 2 assessments presented in the Factsheets and

draws out the recommendations from the Factsheets for further investigation to enable safe

NPPF compliant development in accordance with the requirements of the Exception Test.

1.2 Flood Risk and Planning Policy

The NPPFError! Bookmark not defined. and its associated Flood Risk and Coastal Change PPGError!

Bookmark not defined. form the primary source of statutory planning guidance with regard to new

development and flood risk for England. The overall thrust of national planning policy with regards to flood

risk is to steer new development away from areas of flood risk, as far as possible, through the application of

the ‘Sequential Test’. Development in areas of higher flood risk should only be permitted where application

of the Sequential Test has determined that it is required in order to fulfil local plan policy requirements. A

further test, the ‘Exception Test’ has to be satisfied to demonstrate that development in areas of high flood

risk:

Has wider sustainability benefits to the community that outweigh flood risk; and

The development will be safe for its lifetime (considering the impacts of climate change on

flood risk), taking account of the vulnerability of its users, without increasing flood risk

elsewhere, and, where possible, will reduce flood risk overall.

Requirements for the application of the Sequential and Exception Test are determined through consideration

of the Vulnerability Classification of the proposed development and the Flood Zone in which it is located, as

set out in Table 3 of the PPG. Flood Zone and Vulnerability Classification definitions are provided in Tables 1

and 2 of the PPG respectively.

NPPF requires local planning authorities such as the SDNPA to take flood risk into account when developing

policies and land allocations for Local Plans. Preparation of a SFRA provides the evidence base to facilitate

this. In particular, the NPPF PPG (paragraph 010) states that local planning authorities should use a SFRA to:

Determine the variations in risk from all sources of flooding across their areas, and also the

risks to and from surrounding areas in the same flood catchment;

Inform the sustainability appraisal of the Local Plan, so that flood risk is fully taken into

account when considering allocation options and in the preparation of plan policies,

including policies for flood risk management to ensure that flood risk is not increased;

Apply the Sequential Test and, where necessary, the Exception Test when determining land

use allocations;

Identify the requirements for site-specific flood risk assessments in particular locations,

including those at risk from sources other than river and sea flooding;

Determine the acceptability of flood risk in relation to emergency planning capability; and

Consider opportunities to reduce flood risk to existing communities and developments

through better management of surface water, provision for conveyance and of storage for

flood water.

The NPPF PPG sets out two levels of SFRA (paragraph 011):

A Level 1 Assessment should be carried out in local authority areas where flooding is not a

major issue and where development pressures are low. The assessment should be

sufficiently detailed to allow application of the Sequential Test to the location of

development and to identify whether the development can be allocated outside high and


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medium flood risk areas, based on all sources of flooding, without application of the

Exception Test; and

Where a Level 1 assessment shows that land outside flood risk areas cannot appropriately

accommodate all the necessary development, it may be necessary to increase the scope of

the assessment to a Level 2 to provide the information necessary for application of the

Exception Test where appropriate. A Level 2 SFRA should consider the detailed nature of the

flood characteristics within a flood zone, including flood probability, depth, velocity, rate of

onset, and duration of flooding.

1.3 Isle of Wight Level 2 SFRA Context

Level 1 SFRA

The 2018 Level 1 SFRA represents an update of the 2010 Level 1 SFRA, this is an island wide assessment

which represents the latest flood risk data held by the Environment Agency. The main emphasis of the

update was to ensure that the policy guidance and references were up to date and to ensure that the latest

fluvial flood risk zones were incorporated as the Environment Agency had undertaken some updates since

the publication of the 2010 Level 1 SFRA. In many cases the 2010 Level 1 data and mapping remained the

best available data and has been retained without change. The Level 1 SFRA provides island wide mapping

and island wide commentary. Recommendations for safe development, the scope of Flood Risk Assessments

(FRAs) and drainage assessments are provided generically, location specific discussions are not provided

within the Level 1 SFRA.

The 2018 Level 1 SFRA does however provide the platform for which the Level 2 SFRA has been developed.

In line with the NPPF and PPG, there is consistency between the data underpinning the 2018 Level 1 and

Level 2 SFRAs. The 2018 Level 1 SFRA performed a screening exercise on the 379 SHLAA sites, in which sites

were assigned with a risk score based on the highest risk flood zone that intersected the site. The screening

resulted in sites being assigned a red, amber or green traffic light colour depending on whether the

interested flood zone 3, only interested flood zone 2 or if they were completely within flood zone 1. The

sites are mapped in Figure A11 in Appendix A of the 2018 Level 1 SFRA.

Level 2 SFRA

The scope of the Level 2 SFRA is described in Section 1.1, the focus of this activity is to describe the flood

risks at 14 of the SHLAA sites being proposed for allocation by the Council. The site-specific Level 2

assessments are provided in Appendix A to M, the format of the Factsheets, and supporting information, is

described in Section 1.3 and further expanded in Section 2. The purpose of the Level 2 SFRA Assessment is

two-fold; firstly this was to provide a conclusion, based on available information (as listed in Table 1.1,

Section 1 of the 2018 Level 1 SFRA), as to the suitability of the 14 SHLAA sites for allocation as residential

development. Secondly it is to recommend site layout and design advice to facilitate safe NPPF compliant

development at those sites. This Level 2 SFRA recognises that there are strong other considerations which

the Council has to manage which maintain pressure for making residential allocations at some sites where

flood risks have resulted in the Level 2 SFRA concluding these sites are not suitable. To this end the SFRA, in

the respective Fact Sheets sets out what additional information is required to enable safe development

considerations to be undertaken at the sites assessed to be at higher risk of flooding.

1.4 SHLAA process – Selection of the 14 Level 2 SFRA Sites

The Level 2 SFRA is focused on the assessment of flood risk at 14 SHLAA sites and on the safe, NPPF

compliant development of these sites. The points below describe the process the Isle of Wight Council have

followed to arrive at the 14 sites forming the basis of the Level 2 SFRA.


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A total of 379 potential development sites have been considered by the Isle of Wight

Council (See Figure A 11 in Appendix A of the Level 1 SFRA);

The sites put forward were recorded in GIS, registered in a database and visited, either

onsite or from public vantage points;

The Council has conducted a desk based/GIS based assessment against key criteria to form

an early view on potential suitability;

The overriding principle of selection has been that if a site was in Flood Zone 2 or 3 then it

was discounted. However, if the site was in a brownfield and/or in a regeneration area then

the site has been tagged ‘for review’, and thereby making it the subject of this Level 2 SFRA;

All sites have then been considered by an officer steering group before being put before the

SHLAA panel; and

Where a site has been concluded to be suitable, available and either deliverable and

developable, these have or will be considered in more depth for potential allocation;

The resulting 14 sites, presented in Table 1.1.

Table 1.1 Sites for Assessment in Level 2 SFRA

SHLAA Reference

Number

Address Brownfield or

Greenfield

Flood risk synopsis

IPS027 Former Flamingo Park, Oakhill Road, Seaview

Mixed Partial - To eastern edges only

IPS035 Green Gate Industrial Estate, Thetis Road, Cowes

Brownfield Whole site

IPS055 6-8 George Street, Ryde Brownfield Whole site

IPS077 Former Sandham Middle School Site, Perowne Way, Sandown

Mixed Partial - To north eastern edge only

IPS078 Test Centre site, 23 Medina Avenue, Newport

Brownfield Partial - To south east corner only

IPS117 LAND REAR OF HIGH STREET WHITWELL Greenfield Partial site western edge

IPS135/217 Land north of Perowne Way Greenfield Partial - To west and north area

IPS138B Land on the south-west side of Buckbury Lane, Newport

Greenfield Partial - To west and north area

IPS150 Westridge Cross Dairy and land to the north of Bullen Road, Ryde

Greenfield Partial - Small area to south east tip

IPS215 Manor Farm (West Field), Wellow Greenfield Partial - across south west of the site

IPS342 Land off Gunville Road, (west) Newport Greenfield Partial - across middle of site

IPS350 Buildings at Lee Farm, Wellow Mixed Partial - to south of site and access


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SHLAA Reference

Number

Address Brownfield or

Greenfield

Flood risk synopsis

IPS371 Newport Harbour Brownfield Whole site


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2. Level 2 Site Assessments

This section of the Level 2 SFRA presents the assessment methodology applied to create

the Level 2 Factsheets and associated mapping.

2.1 Sources of information

The Level 2 SFRA utilises the same flood risk information as the Level 1 SFRA, which is described in Section 3

of the Level 1 SFRA. The Level 2 SFRA, analyses this data at a site-specific rather than island wide level. The

same climate change uplift factors are applied as described in Section 4 of the Level 1 SFRA.

Recommendations for accounting for climate change are separately provided in Section 2.3.

2.2 SFRA Level 2 Approach

Overview

The Level 2 SFRA approach has been to undertake site-specific assessments and to record these in a series of

14 Factsheets with one corresponding to each of the 14 SHLAA sites, put forward for assessment by the

Council. The specific contents of the Factsheets are outlined later in this section. Table 2.1 details where

each of the Factsheets can be found in the Level 2 SFRA. Associated with each Factsheet are the four

following maps:

Site location map;

LiDAR ground elevation map;

Surface water flood risk extent map

Flood Zone 2 and 3 extents and tidal flood extent maps for 2115

Table 2.1 SHLAA Site-Specific Assessment Factsheet locations

SHLAA Reference Number Address Located in

Appendix

IPS027 Former Flamingo Park, Oakhill Road, Seaview A

IPS035 Green Gate Industrial Estate, Thetis Road, Cowes B

IPS055 6-8 George Street, Ryde C

IPS077 Former Sandham Middle School Site, Perowne Way, Sandown D

IPS078 Test Centre site, 23 Medina Avenue, Newport E

IPS117 LAND REAR OF HIGH STREET WHITWELL F

IPS135/217 Land north of Perowne Way G

IPS138B Land on the south-west side of Buckbury Lane, Newport H

IPS150 Westridge Cross Dairy and land to the north of Bullen Road, Ryde I


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SHLAA Reference Number Address Located in

Appendix

IPS215 Manor Farm (West Field), Wellow J

IPS342 Land off Gunville Road, (west) Newport K

IPS350 Buildings at Lee Farm, Wellow L

IPS371 Newport Harbour M

Level 2 Factsheet Structure

The 14 Factsheets are comprised of consistent set of six sections, the generic contents of which are described

below.

General Information

The introductory section of each Factsheet sets out the site address, a brief description of the site, the size of

the site, potential yields and proposed allocations – information all provided by the Council

Baseline Flood Risk Summary

This section of the Factsheet provides a site-specific qualitative assessment of flood risk, using the same

datasets from the 2018 Level 1 SFRA (see Section 2.1). Additional numerical quantitative analysis additional

to the Level 1 SFRA has not been undertaken as this is not necessary (See Section 1.1). Where relevant the

site-specific assessment includes:

Commentary on the tidal flood risk and the location of any sea defences along with the

identification of relevant areas benefiting from defences. The performance of the defences

is not assessed nor are defence failure scenarios;

Commentary on the fluvial flood risk and the location of any fluvial defences along with the

identification of relevant areas benefiting from defences. The performance of the defences

is not assessed nor are defence failure scenarios;

A description of the surface water flood risk maps and their proximity to the site and where

relevant the pathways through the site are discussed;

The underlying geology and superficial geology is reviewed to provide a high level

assessment of groundwater flood risk potential;

Reservoir flooding is reviewed and reported where relevant; and

Sewer flooding incidents are reported where they have been captured in the Level 1 SFRA.

Site Suitability

Based on the assessment in the ‘Baseline Flood Risk Summary’ section, an assessment of the suitability of the

site for the proposed allocation is made. This assessment typically falls into one of three categories:

considered suitable;

considered suitable, subject to further consideration of specific risks; or

further work required to determine suitability.


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Policy Recommendations

This section summarises the pertinent flood risk related policy requirements which apply to the development

of the site

Site-Specific Recommendations for NPPF Compliant Development

The recommendation in this section are subject to the risks identified in the baseline flood risk assessment in

part 1 of the Factsheet. The intention of this section of the Factsheet is to provide a series of site-specific

design recommendations which a developer may wish to consider when designing the site. Please note that

the recommendations listed are not exhaustive and are recommendations for consideration only and do not

guarantee that alone will secure planning approval, full consideration of the risks are required as part of the

completion of a competent FRA by the applicant.

Drainage Management Recommendations

The intention of this section of the Factsheet is to provide a series of site-specific design recommendations

which a developer may wish to consider when considering the sustainable management of surface water

from the site. Please note that the recommendations listed are not exhaustive and are recommendations for

consideration only and do not guarantee that alone will secure planning approval, full consideration of the

risks are required as part of the completion of a competent FRA by the applicant.


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3. Supporting the Application of the Exception

Test

The information provided in this section should be reviewed alongside Section 7, 8 and 9

of the Level 1 SFRA – only a summary is provided here in the Level 2 SFRA. The guidance

in this section is in addition to the development recommendations provided on a sit-

specific level in Appendices A to M.

3.1 The Exception Test

Developments are also classified according to their flood risk vulnerability as set out in Table 2 (presented in

Table 3.3 below) of the NPPF planning guidance on Flood Risk and Coastal Change. The allocations assessed

in this SFRA fall in to two of the five vulnerability classes. The Gypsy and Traveller sites are classed as ‘Highly

Vulnerable’ as they provide pitches for caravans to be used for permanent residential homes. Buildings used

for dwelling houses are classified as ‘More Vulnerable’. The mixed use allocations will also fall into the ‘More

Vulnerable’ class even though shops, restaurants, office space, and similar non-residential developments

alone are classified as ‘Less Vulnerable’. Table 3 of the NPPF guidance combines the information in Tables 1

and 2 of the guidance to provide flood risk vulnerability and flood zone ‘compatibility’ matrix as shown in

Table 3.1

Table 3.1 Flood Risk Vulnerability and Flood Zone ‘Compatibility’

Flood Zones Highly Vulnerable

Development

More Vulnerable

(Residential, Mixed Use)

Less Vulnerable

(Commercial)

1 - Land having a less than 1 in 1,000 AEP of river or sea flooding

2 - Land having between a 1 in 100 and 1 in 1,000 AEP of river flooding; or land having between a 1 in 200 and 1 in 1,000 AEP of sea flooding

Exception Test required

3a - Land having a 1 in 100 or greater AEP of river flooding; or Land having a 1 in 200 or greater AEP of sea flooding.

✘ Exception Test required

3b - This zone comprises land where water has to flow or be stored in times of flood. For the purposes of this report, and where appropriate modelling outputs are available, it has been defined as land having a less than or equal to 1 in 20 AEP risk of river or sea flooding.

✘ ✘ ✘

Where: indicates development is appropriate and ✘indicates development is inappropriate. The full table is provided in the NPPF.


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Application of the Exception Test

The Factsheets provided in Appendices A to M provide an overview of flooding from all sources, the baseline

risk information and safe development recommendations can be used to establish the likely type and scale of

mitigation measures that will be required to make a site safe for habitation.

The Exception Test recognises that there will be some exceptional circumstances when development within

higher risk zones is unavoidable. The allocation of necessary development must still follow the sequential

approach and where exceptions are proposed, the Exception Test must be satisfied when the development is

classified as:

highly vulnerable and in flood zone 2;

essential infrastructure in flood zone 3a or 3b; and

more vulnerable in flood zone 3a.

Passing the Exception Test

NPPF states that the Exception Test should only be undertaken after the Sequential Test has been applied.

The successfully applied Sequential Test must demonstrate that there are no other reasonably alternative

sites available in zones of lower flood risk. The allocation of the site by the Isle of Wight Council for

residential purposes confirms that the Sequential Test for the Site has been passed.

Once the Sequential Test has been applied and passed, NPPF requires the following criteria to be met to pass

the Exception Test:

it must be demonstrated that the development provides wider sustainability benefits to the

community that outweigh flood risk, informed by a Strategic Flood Risk Assessment where

one has been prepared; and

a site-specific flood risk assessment must demonstrate that the development will be safe for

its lifetime taking account of the vulnerability of its users, without increasing flood risk

elsewhere, and, where possible, will reduce flood risk overall.

Both elements of the test will have to be passed for development to be permitted. The Isle of Wight Council

should be approached for information supporting the evidencing of the application of the Sequential Test

during the site allocation process.

3.2 Allowing for Climate Change

The climate change guidance relates to river flows, rainfall intensity and sea levels, these are addressed in the

following three sections and should be accounted for when performing site-specific flood risk assessments.

The climate change guidance to inform site-specific FRAs and the application of the Exception Test is the

2017 Environment Agency Guidance - Flood risk assessments: climate change allowances4

Climate Change and River Flows

The climate change uplift values reflect different future emissions scenarios and they are based on

percentiles to reflect the uncertainty within the estimates. The guidance promotes a risk-based approach to

the level of conservatism in the climate change uplift to apply, depending upon the vulnerability of the

development type and the risk zone within which the development is proposed. Table 1 in the 20174

Environment Agency Guidance presents a full list of fluvial uplift percentages for river flows. When

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


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interpreting the guidance, note that the Isle of Wight is in the South East River Basin District, as defined by

the Environment Agency, the pertinent values to the Isle of Wight are presented in Table 3.2

Table 3.2 South East River Basin District – Peak River Flow Allowances (using a 1961 to 1990 baseline)

Allowance Category Total potential change

anticipated for the ‘2020s’

(2015 to 2039)

Total potential change


(2040 to 2069)



(2070 to 2115)

Upper end 25% 50% 105%

Higher Central 15% 30% 45%

Central 10% 20% 35%

Source – Table 1 https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances#table-1

The flood zone designation at the site in question needs to be considered along with the development type

classification, see Table 3.3. This will enable the developer to understand the range of potential impacts that

need to be considered to facilitate safe development, the guidance on which uplift factor to apply is

presented in Table 3.4.

Table 3.3 Flood Risk Vulnerability Classifications

Flood Risk Vulnerability

Classification

Examples

Essential infrastructure Essential transport infrastructure (including mass evacuation routes) which has to cross

the area at risk.

Essential utility infrastructure which has to be located in a flood risk area for

operational reasons, including electricity generating power stations and grid and

primary substations; and water treatment works that need to remain operational in

times of flood.

Wind turbines

Highly vulnerable Police and ambulance stations; fire stations and command centres;

telecommunications installations required to be operational during flooding.

Emergency dispersal points.

Basement dwellings.

Caravans, mobile homes and park homes intended for permanent residential use.

Installations requiring hazardous substances consent. (Where there is a demonstrable

need to locate such installations for bulk storage of materials with port or other similar

facilities, or such installations with energy infrastructure or carbon capture and storage

installations, that require coastal or water-side locations, or need to be located in other

high flood risk areas, in these instances the facilities should be classified as ‘Essential

Infrastructure’).

More vulnerable Hospitals

Residential institutions such as residential care homes, children’s homes, social services

homes, prisons and hostels.

Buildings used for dwelling houses, student halls of residence, drinking establishments,

nightclubs and hotels.

Non–residential uses for health services, nurseries and educational establishments.

Landfill* and sites used for waste management facilities for hazardous waste.

Sites used for holiday or short-let caravans and camping, subject to a specific warning

and evacuation plan.

Less vulnerable Police, ambulance and fire stations which are not required to be operational during

flooding.


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Flood Risk Vulnerability

Classification

Examples

Buildings used for shops; financial, professional and other services; restaurants, cafes

and hot food takeaways; offices; general industry, storage and distribution; non-

residential institutions not included in the ‘more vulnerable’ class; and assembly and

leisure.

Land and buildings used for agriculture and forestry.

Waste treatment (except landfill* and hazardous waste facilities).

Minerals working and processing (except for sand and gravel working).

Water treatment works which do not need to remain operational during times of flood.

Sewage treatment works, if adequate measures to control pollution and manage

sewage during flooding events are in place.

Water-compatible

development

Flood control infrastructure.

Water transmission infrastructure and pumping stations.

Sewage transmission infrastructure and pumping stations.

Sand and gravel working.

Docks, marinas and wharves.

Navigation facilities.

Ministry of Defence defence installations.

Ship building, repairing and dismantling, dockside fish processing and refrigeration

and compatible activities requiring a waterside location.

Water-based recreation (excluding sleeping accommodation).

Lifeguard and coastguard stations.

Amenity open space, nature conservation and biodiversity, outdoor sports and

recreation and essential facilities such as changing rooms.

Essential ancillary sleeping or residential accommodation for staff required by uses in

this category, subject to a specific warning and evacuation plan.

Table 3.4 Application of Peak River Flow Uplifts Based on Flood Zone and Development Vulnerability

Flood Zone River flow allowances

In Flood Zone 2 essential infrastructure – use the higher central and upper end to assess a range of

allowances

highly vulnerable – use the higher central and upper end to assess a range of

allowances

more vulnerable – use the central and higher central to assess a range of allowances

less vulnerable – use the central allowance

water compatible – use none of the allowance

In Flood Zone 3a essential infrastructure – use the upper end allowance

highly vulnerable – development should not be permitted

more vulnerable – use the higher central and upper end to assess a range of

allowances

less vulnerable – use the central and higher central to assess a range of allowances

water compatible – use the central allowance

In Flood Zone 3b essential infrastructure – use the upper end allowance

highly vulnerable – development should not be permitted

more vulnerable – development should not be permitted

less vulnerable – development should not be permitted

water compatible – use the central allowance


October 2018


Climate Change and Peak Rainfall Intensity

The 20174 Environment Agency Guidance provides a nationwide consideration of climate change impacts on

peak rainfall intensity. Site-specific FRAs should assess both the central and upper end allowances to

understand the range of impacts, these are presented in Table 3.5.

Table 3.5 Peak Rainfall Intensity Allowance in Small and Urban Catchments (use 1961 to 1990 baseline)

Allowance Category Total potential change


(2015 to 2039)



(2040 to 2069)



(2070 to 2115)

Upper end 10% 20% 40%

Central 5% 10% 20%

Source – Table 2 https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances#table-2

Climate Change and Sea Level Rise

The 2018 Isle of Wight Level 1 SFRA presents the flood risk extent predictions associated with the 1:200yr and

1:1000yr sea level in the year 2115, these results are based on the uplift factors in Table 4 of NPPF1 which are

consistent with the 2017 Environment Agency Guidance4 sea level rise uplifts. The coastal flood risk

assessments undertaken in the Fact sheets in Appendices A to M, account for the 2115 sea level rise

estimates, the associated peak water levels are provided in Figure E1 of Appendix E in the Isle of Wight Level

1 SFRA.

3.3 Site-Specific Flood Risk Assessments

Site-specific FRAs should accurately define the baseline flood risk at development sites, infilling gaps in the

understanding of flood risk as necessary to assess the risk to proposed development. This information can

be assessed against the characteristics/vulnerability of the proposed development to understand the

potential consequences and to inform the appropriate flood risk mitigation measures and SuDS strategies

(summary below) to manage flood risk and surface water. The FRA requirements are intended to ensure that

development at each site is consistent with policy recommendations and the latest climate change

allowances (see Section 3.2). Key recommendations for site specific FRAs are summarised below in Box 3.1:

Flood risk management recommendations for each site are provided in the fact sheets in Appendices A to M.

These recommendations are key considerations for the site in question. However, application of these

principles is good practice for all new developments. These measures are intended to guide the approach to

managing flood risk at the site from the earliest stages of site assessment, through to finalisation of the

masterplan and development form.


October 2018


Use of SuDS

SuDS should be incorporated in all developments, as far as practically possible. For sites with fewer

constraints on drainage, a broad range of SuDS techniques may be applicable. Conversely, the range of

SuDS options may be limited where there are constraints, particularly brownfield sites or within areas of flood

risk. In all cases, pre-planning consultation with the organisation (Council, Environment Agency or Southern

Water) responsible for the receiving watercourse or drainage system will be needed to agree acceptable rates

and volumes for the site’s runoff. If SuDS are genuinely unfeasible, agreement will need to be reached at this

stage.

The developer should consider the SuDS guidance provided in Section 8 of the Isle of Wight Level 1 SFRA. In

particular, the CIRIA SuDS Manual (C753)5 provides detailed guidance on how to incorporate SuDS

techniques into new developments. Developers of sites should consider and incorporate SuDS at the outset

of site master planning, in order to best incorporate SuDS and design well-conceived sites with quality green

and blue infrastructure. Early consultation with the Council is required to agree the principles for a site

drainage system and to determine any site-specific drainage measures. This process will also need to

consider key design parameters, as set out in Defra’s SuDS Non-Statutory Technical Standards guidance6.

5 The SuDS Manual (C753). CIRIA, London. 6 Defra, (March 2015). Sustainable drainage systems, non-statutory technical standards for sustainable drainage systems.

Box 3.1 Summary of considerations for a site-specific FRA

l Design flood level for sites to be defined using current, up to date, climate change

allowances. If undertaking additional modelling is disproportionate to the size of the

proposed development, an appropriate freeboard allowance for raising may need to be

agreed with the EA and the Council in lieu of detailed level information.

l New site masterplans should be designed to ‘managed for exceedance’, such that

above the design event surface water flows are safely conveyed through the site in a

similar manner/direction to existing runoff pathways (typically by the road

network/greenspaces), to minimise the risk of property flooding.

l Site masterplans should avoid directing new development to areas at significant risk of

surface water flooding (i.e. mapping indicates flow paths crossing the site or deep

ponding in depressions and upslope of embankments). Developments should avoid

displacing flood water off-site.

l Development access routes should be suitably designed to ensure access and egress

are maintained to the design event, with arrangements for residual risk clearly

stated. New roads should be designed so as not to block or divert surface water flow

paths such that flood risk to existing or new development is increased.

l Where ground raising is proposed in Flood Zone 3, level-for-level compensatory

storage will typically be required in fluvial flood risk and defended tidal flood risk zones

to avoid displacing flood water off-site. Compensatory storage should be designed to

ensure that flood risk to third parties is not increased.

l Further site-specific assessment of groundwater flood risk, considering potential

climate change impacts over the lifetime of the development.

l Drainage impact assessment.


October 2018


SuDS design should consider the management of exceedance flows for events that exceed the design

standard for the SuDS system. Proposed measures for maintenance and adoption must be considered

throughout the design process,and set out in accordance with LLFA guidance for planning applications.

A1 © Wood Environment & Infrastructure Solutions UK Limited


October 2018


Appendix A

IPS027 - Former Flamingo Park, Oakhill Road,

Seaview


October 2018

Isle of Wight Level 2 SFRA – Flood Risk Information Sheet

General information

Site Address Former Flamingo Park, Oakhill Road, Seaview, PO34 5AP

Site Description Former wildlife park. The site slopes from north to east and has a mix of trees, hedgerows and ponds within and bounding

the site.

Site ID IPS027 Area (ha) 6.4

Current land use Mix Proposed allocation type Residential

Indicative yield 9 units Proposed development Aspirational housing


There is a risk of tidal flooding. The site is approximately 130 m south-west of the coast. There are coastal defences comprising 856 m of sea wall and a flood

gate, built in 2008 to a 1% AEP standard of protection. EA spatial defences mapping indicates these structures are of good condition. EA flood mapping

shows an area of FZ2 and 3 along the entire eastern side of the site at an average width of 40 m. The area of FZ3 is shown as being an area benefitting from

defences whereas the area of FZ2 does not due to the SoP of the flood defences. SFRA Level 1 modelling shows that the 2115 0.5% & 0.1% AEP tidal events

would increase the flood extent along the eastern boundary by approximately 50 m.

There is no risk of fluvial flooding.

There is an area of SW flood risk (primarily high) contained within the site along the eastern side with an average width of 25 m. However, this area coincides

with an existing pond and is indicative of the underlying topography. It is noted that this area does not appear to be in connectivity with the wider area (i.e. it

has no upstream catchment).

The risk of GW flooding is inconclusive. While the solid geology comprises clay, silt and sand, this in overlain by Alluvium in the east of the site together with

slowly permeable, seasonally waterlogged fine loams over clay, there are a number of ponds / lagoons in the surrounding area, possibly in connectivity with

the pond on-site, water levels in which may be influenced by groundwater levels.

There is no risk of reservoir flooding to the site.

Sewer flooding was not identified as an issue in Seaview by the Level 1 SFRA.

Site Suitability

On the basis of the information provided, this site is considered suitable for residential development subject to the consideration of policy and NPPF

compliance recommendations below.


In accordance with PPG Tables 2 & 3, housing is classed as more vulnerable and thus development should not be permitted within FZ3.

The Exception test would need to robustly demonstrate that the wider sustainability benefits outweigh flood risk and that the development will be

safe throughout its lifetime, to include allowances for climate change.

Drainage water discharge points (i.e. to waterbodies) will be subject to a FRAP from the EA for main rivers and/or OWC from the LLFA for ordinary

watercourses.


Sustainable drainage solutions should be implemented, where possible (see drainage management recommendations below).

Site access/egress should be to/from the west of the site.

Development of housing should be directed away from the areas within the site which fall within the FZ3 extent.

It should be demonstrated that developed areas avoid the areas of SW and GW flood risk or that those issues are adequately mitigated.

It should be demonstrated that the SW and GW baseline flood issues are not made worse via hydraulic structures or obstructions to flow that might

exacerbate on site flooding and also increase off-site flood risk.

Further investigation into areas benefitting from defences should be undertaken, as the current data is inconclusive.


All feasible SuDS options should be assessed, whilst adhering to the SuDS hierarchy, as set out in the SRFA report.

Assessing the feasibly of using infiltration techniques via site investigation. The underlying soil and geology characteristics indicate that infiltration

may be possible and, if it is, this would be the preferred method of partially/wholly discharging water from the site.

The greenfield runoff rate should be determined for the site using current best practice. This will allow for the appropriate sizing of attenuation and

conveyance SuDS to ensure that sufficient space for drainage infrastructure is provided in developing site masterplans.

Drainage design should include recommended allowances for climate change.

The topography of the site should be taken in to consideration to ensure that gravity drainage is possible throughout the whole site.

An appropriate discharge location should be identified (if not all infiltration) and appropriate consultations should be had regarding FRAP and OWC

considerations.

© Crown Copyright. All rights reserved. Licence number AL100001776.

Isle of WightStrategic Flood Risk Assessment

1:4,000Scale at A3:

Site location planIPS027Former Flamingo Park, Oakhill Road,Seaview, PO34 5AP

October 2018

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Is le of WightStrate gic Flood Ris k As s e s s m e nt

Present day fluvial and tidal Flood Zoneextents, and future tidal flood zone extentswith climate change to 2115IPS027Former Flamingo Park, Oakhill Road,Seaview, PO34 5APOc tobe r 2018

Key

Site Boundary

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Are as Be ne fiting from Flood De fe nc e s

Historic al Flood ing

Flood Z one 2

Flood Z one 3

Tidal Flood Z one 2 with c lim ate c hangeto 2115Tidal Flood Z one 3 with c lim ate c hangeto 2115

G:\MODEL\PROJECTS\HM-250\41017 LDN IoW SFRA\GIS\MXD\41017Ld n018.mxd Originator: sarah.butler

© Crown Copyright. All rights re s e rve d . Lic e nc e num be r AL100001776.1:4,000Sc ale at A3:

0 40 80 120 160 200m

Flood Z one 2 - land as s e s s e d as having be twe e n a 1 in 100and 1 in 1,000 annual probability of rive r flood ing (1% –0.1%), or be twe e n a 1 in 200 and 1 in 1,000 annualprobability of s e a flood ing (0.5% – 0.1%) in any ye ar.Flood Z one 3 - land as s e s s e d as having a 1 in 100 orgre ate r annual probability of rive r flood ing (>1%), or a 1 in200 or gre ate r annual probability of flood ing from the s e a(>0.5%) in any ye ar.

Future flood zone s 2 and 3 dis play tidal flood e xte nt only(not fluvial).

Isle of Wig htStra te g ic Flood Risk Asse ssm e nt

Surface water flood risk extentIPS027Former Flamingo Park, Oakhill Road,Seaview, PO34 5APO ctob e r 2018

Key

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G:\MODEL\PROJECTS\HM-250\41017 LDN IoW SFRA\GIS\MXD\41017Ldn019.mxd Originator: sarah.b utler

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Hig h risk – la nd a sse sse d a s having a 1 in 30 or g re a te ra nnu a l prob a b ility of su rfa ce wa te r flooding (3.33%) in a nyye a r.Me diu m risk – la nd a sse sse d a s having b e twe e n a 1 in 30and 1 in 100 a nnu a l prob a b ility of su rfa ce wa te r flooding(3.33% - 1%) in a ny ye a r.Low risk – la nd a sse sse d a s having a b e twe e n a 1 in 100and 1 in 1,000 a nnu a l prob a b ility of su rfa ce wa te r flooding(0.1% - 1%) in a ny ye a r.


LiDAR ground elevationIPS027Former Flamingo Park, Oakhill Road,Seaview, PO34 5AP

October 2018

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Site BoundaryContour line (interval 2m)

Elevation - 1m LiDAR DTM

Light Detection and Ranging (LiDAR) is an airbornemapping technique, which uses a laser to measurethe distance between the aircraft and the ground. The spatial resolution is 1m. This can be used to provide information about the elevation andgradient of the site.

0 m

39

B1 © Wood Environment & Infrastructure Solutions UK Limited


October 2018


Appendix B

IPS035 - Green Gate Industrial Estate, Thetis Road,

Cowes


October 2018


General information

Site Address Green Gate Industrial Estate, Thetis Road, Cowes PO31 7DJ

Site Description Former industrial site that has remnants of industrial buildings and plant. Site is adjacent to Thetis Road and mostly

comprises hardstanding.


Current land use Brownfield Proposed allocation type Residential

Indicative yield 10 Proposed development Flats


The site is at risk of tidal flooding, due to its location approximately 80 m west of the mouth of the River Medina. Flood defences in the form of bank

protection end approximately 120 m north-east of the site. As such, the site is not in an ABD. Approximately 60% of the east portion of the site is located in

FZ3. Nearly all of the site is at risk of tidal flooding under the 2115 FZ3 scenario.

There is no risk of fluvial flooding at the site. Due to the proximity to the estuary mouth, any fluvial events, either at low tide or in joint probability with a tidal

event, would be of no consequence.

Approximately 25% of the site to the east is subject to a low risk of SW flooding. This SW originates at the site and does not run off. There is no SW flood risk

to the access road, west of the site.

There is a low risk of GW flooding at the site. Solid geology at the site comprises clay, silt and sand, overlain by alluvium and soils which are slowly

permeable, seasonally waterlogged and consist of fine loam over clay. The site and the surrounding area are covered by impermeable surfaces (as it was an

industrial site), hence GW flooding is unlikely.


Sewer flooding was not identified as an issue in Cowes by the Level 1 SFRA.

Site Suitability

On the basis of the information provided, further work is required to determine the suitability of this site for residential development, mainly due to the tidal

flood risk.


In accordance with PPG Tables 2 & 3, housing is classed as more vulnerable and thus development should not be permitted within FZ3.



In accordance with NPPF Footnote 50, a site-specific FRA is required, as the site is located within Flood Zone 3.


Safe access and egress to the site should be from Thetis Road.


The construction and operation of the development should not exacerbate flood risk to the site or 3rd parties.

Further investigation is required to establish the protection from defences.

Further investigation is needed into GW flood risk.


As the existing site has hard surfaces, housing development will not increase the impermeable area.


Discharge at this site will likely be to the sewer network. Appropriate consultations should be conducted with Southern Water regarding capacity,

requirements and outfall location.



1:4,000Scale at A3:

Site location planIPS035Green Gate Industrial Estate, Thetis Road,Cowes PO31 7DJ

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Present day fluvial and tidal Flood Zoneextents, and future tidal flood zone extentswith climate change to 2115IPS035Green Gate Industrial Estate, Thetis Road,Cowes PO31 7DJOc tobe r 2018

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Surface water flood risk extentIPS035Green Gate Industrial Estate, Thetis Road,Cowes PO31 7DJO ctob e r 2018

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LiDAR ground elevationIPS035Green Gate Industrial Estate, Thetis Road,Cowes PO31 7DJ

C1 © Wood Environment & Infrastructure Solutions UK Limited


October 2018


Appendix C

IPS055 - 6-8 George Street, Ryde


October 2018


General information

Site Address 6-8 George Street, Ryde, IOW, PO33 2EB

Site Description Currently a garage, showroom and car park located in Ryde. The building is mostly single storey with a two-storey element at

the back beyond the parking/internal courtyard.



Indicative yield 10 Units Proposed development Flats


The whole site is at risk of tidal flooding under the 2115 FZ3 scenario. Under current conditions, the site is located entirely within FZ1. However the site is

within 100m of the coast and at an elevation of approx. 4-6 mAOD.

There is no risk of fluvial flooding at the site. The nearest watercourse (Monktonmead Brook) is approx. 600 m east of the site.

There is a large area through the middle of the site, at low-medium risk of flooding from SW, which appears to arise as a result of SW flowing down Union Rd

and George St and ponding in a low point on the site.

There is a risk of GW flooding. While the solid geology comprises clay, silt and sand, this is overlain by slowly permeable, seasonally waterlogged fine loams

over clay. However the site itself is covered by impermeable surfaces, but the Level 1 SFRA found the Ryde area has a history of basement flooding.


Sewer flooding was identified as an issue in Ryde. The Level 1 SFRA found that Ryde sustained severe damage during the floods in 2000. 72 properties were

flooded, because sewers became overwhelmed and because high water levels in Monkton Mead Brook prevented free discharge of storm drains.

Site Suitability

On the basis of the information provided the site is considered suitable for residential development, subject the consideration of residual risk arising during

overtopping and breach events under climate change scenarios and the policy and recommendations sections below.


In accordance with PPG Table 2, previous land use (garage, showroom and car park) is categorised as ‘general industry’ and classed as less vulnerable.

In accordance with PPG Tables 2 & 3, housing is classed as more vulnerable, so development in Flood Zone 1 is appropriate.

In accordance with NPPF Footnote 50, a site-specific FRA would be required, as the land may be subject to surface water flooding and the

development will introduce a more vulnerable use.


The inclusion of basement units should be given careful consideration in terms of adequate tanking due to the risk of GW flooding.

The development should be made safe for its lifetime, including mitigating against the residual risk of future tidal flooding.

The flow of SW on to the site should be investigated and mitigated without increasing the off-site risk of surface water flooding relative to the

baseline.

Access and egress to the site from Castle St or George St should be made safe from SW flooding.



As the site is already home to a garage, showroom and car park on brownfield land, it already has impermeable surfaces and conversion to flats

should not result in an increase of impermeable surfaces.

All feasible SuDS options should be assessed, whilst adhering the SuDS hierarchy, as set out in the SRFA report.

Drainage design should include allowances for CC.

Due to the brownfield nature of the site, and because of its small size, the incorporation of SuDS may not be feasible and thus Discharge at this site

will likely be to the sewer network. Appropriate consultations should be conducted with Southern Water regarding capacity, requirements and outfall

location.



1:4,000Scale at A3:

Site location planIPS0556-8 George Street, Ryde, IOW, PO33 2EB

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Present day fluvial and tidal Flood Zoneextents, and future tidal flood zone extentswith climate change to 2115IPS0556-8 George Street, Ryde, IOW, PO33 2EB

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Surface water flood risk extentIPS0556-8 George Street, Ryde, IOW, PO33 2EB

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LiDAR ground elevationIPS0556-8 George Street, Ryde, IOW, PO33 2EB


D1 © Wood Environment & Infrastructure Solutions UK Limited


October 2018


Appendix D

IPS077 - Former Sandham Middle School Site,

Perowne Way, Sandown


October 2018


General information

Site Address Former Sandham Middle School Site, Perowne Way Sandown

Site Description The site comprises part of the old former Sandham Middle School site. The buildings have been demolished and the area is

now vacant. Part of the site is covered by scrub and concrete pads.


Current land use Mix Proposed allocation type Residential

Indicative yield 82 Proposed development Older persons’ accommodation


The site is at risk of tidal under the 2115 0.5% and 0.1% AEP scenarios. Under current conditions, the site is located entirely within FZ1. The site is located

within 850 m of the coast, at an elevation of 4-10 mAOD. However the site is also located within 150 m of the tidal reach of the River Yar. SFRA 2115 0.5%

AEP tidal flood outline shows that under the 0.1% AEP with CC uplift to 2115, approximately 40% of the north and east of the site would be flooded.

Furthermore, in some places in and around the site, the historic flood outline is more extensive than the 2115 01% AEP extent.

As mentioned above, the site is located entirely within FZ1 although there may be a risk of fluvial flooding to the site from the River Yar and an unnamed

tributary of the Yar, to the immediate west of the northwest corner of the site, the latter may not necessarily have been included in the flood mapping due to

its small size. LiDAR and SW mapping indicate that there is small unnamed (possibly ephemeral) watercourse, running from Perowne Way, along the eastern

edge of the site, which may also pose a flood risk.

There are areas of SW flood risk at the site. There is a high risk of SW flooding along the eastern edge of the site, with an average width of 9 m which appears

to coincide with an unnamed small watercourse, and it is unclear if this is actually a SW or fluvial flood risk. Along the north-western edge of the site, there is

a low risk of flooding from SW, which originates from the nearby sports ground and flows offsite towards the River Yar. Additionally there is a small area of

SW flood risk, contained within the site in the vicinity of the old school car park.

There is a potential risk of GW flooding at the site despite the solid geology comprising mudstone overlain by slowly permeable seasonally waterlogged clay.

The Level 1 SFRA did find that high groundwater levels can impose a high baseflow on the River Yar and exacerbate fluvial flooding and, due to the proximity

to the watercourse to the west and the smaller feature along the east of the site, and the fact that these watercourses drain to an area of lowing marshland

(inc. nature reserves) along the riparian zone within 250 m of the Yar to the north.


Sewer flooding was not identified as an issue in Sandown by the Level 1 SFRA.

Site Suitability

On the basis of the information provided the site is considered suitable for residential development, subject to developing a greater understanding of the

tidal and fluvial flood risks, including in context of historic outlines and 2115 scenarios, and subject to the considerations set out in the policy and

recommendations sections below.


In accordance with PPG Tables 2 & 3, housing is classed as more vulnerable, so development in FZ1 is appropriate.

In accordance with NPPF Footnote 50, a site-specific FRA would be required, as the site area is >1 ha.

Drainage water discharge points (i.e. to watercourses) will be subject to a FRAP from the EA for any discharge to the River Yar and/or an OWC from

the LLFA for any discharge to an ordinary watercourse.


Further investigation should be conducted into the watercourses to the west and east of the site with respect to better understanding fluvial flood

risk from these sources.

Development of housing should be directed towards the south of the site, which is not at risk from SW flooding, may be at less risk of future tidal

flooding as a result of CC, and potentially at least risk of fluvial flooding should this be shown to be an issue.

If it’s not possible to direct housing development to the south of the site the priority should be to ensure it is directed away from the watercourse on

the eastern edge of the site; and the development should be made safe for its lifetime, including mitigating against future tidal flood risk.

SW should be directed away from the housing, without increasing flood risk to 3rd parties and this should be detailed in a drainage strategy.

The construction and operation of the development should not exacerbate SW or fluvial flood risk (if identified).



The site is currently a mix of greenfield and brownfield land and the initial proposed site plan will also be a mix of greenfield and brownfield land. It is

recommended that impermeable surfaces are not increased, if possible.

All feasible SuDS options should be assessed, whilst adhering to the SuDS hierarchy, as set out in the SRFA report, to include assessing the feasibility

of infiltration SuDS via site investigations.

The greenfield runoff rate should be determined for the site, using current best practice.

The surface water storage requirements should be determined for the site, using current best practice, to determine the appropriate volume of

attenuation SuDS needed. This should inform the site masterplans.

Drainage design should include allowances for climate change.

The initial proposed site plan (Option 1) includes a biodiversity / nature zone in the north of the site. This could potentially be a good location for

SuDS attenuation storage, subject to confirming whether fluvial flooding is an issue in this area.

An appropriate discharge location should be identified and appropriate consultations should be had regarding FRAP and/or OWC applications.



1:4,000Scale at A3:

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October 2018

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33Elevation - 1m LiDAR DTM

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E1 © Wood Environment & Infrastructure Solutions UK Limited


October 2018


Appendix E

IPS078 - Test Centre site, 23 Medina Avenue,

Newport


October 2018


General information

Site Address Test Centre site, 23 Medina Avenue, Newport PO30 1EL

Site Description Currently a driving test centre and offices within Newport. The site is lower than the adjacent highway with trees to the

northern boundary.



Indicative yield 5-10 Proposed development Standard detached/semi


There is no risk of tidal flooding at the site. The 2115 0.1% AEP tidal event extent ends approximately 150 m north of the site.

The site is located approximately 20 m west of the River Medina. Approximately 20% of the site on the south-eastern side is located in FZ3. The River Medina

does have a natural river bank defence, but this is only designed to withstand the 2% AEP fluvial event. As such, the site is not in an ABD.

The central 20% of the site is subject to a medium risk of SW flooding. A further 20% of the site is subject to a low risk of SW flooding. There is also a low risk

of SW flooding on the access road, to the west of the site corresponding with the existing car park. The SW area is entirely within the site boundary and not in

connectivity with off-site areas.

There is a risk of GW flooding, due to the semi-permeable nature of the soils and geology. The solid geology comprises clay, silt and sand, overlain by

medium loamy soils, variably affected by GW.


Sewer flooding was not identified as an issue in Newport by the Level 1 SFRA.

Site Suitability

On the basis of the information provided, this site is considered suitable for residential development subject to the consideration of policy and NPPF

compliance recommendations below.


In accordance with PPG Tables 2 & 3, housing is classed as more vulnerable and thus areas within FZ3 should be avoided or the Exception Test would

need to be passed.



In accordance with NPPF Footnote 50, a site-specific FRA is required, as part of the site is in FZ3.

Drainage water discharge points to the River Medina (if used) will be subject to a FRAP from the EA.


Development of housing should be directed towards the north of the site.

Further investigation is required into the current state of flood defences and any potential future plans for improvement.

Further investigation is needed into GW flood risk, particularly if basements are to be considered as part of the development.

Sustainable drainage solutions should be implemented where possible (see drainage management recommendations below), and located outside of

FZ3 with an allowance for climate change.

The construction and operation of the development should not exacerbate fluvial or SW flood risk to the site or 3rd parties.


As the current site is on hardstanding land, housing development will not increase the impermeable area.

All feasible SuDS options should be assessed, whilst adhering to the SuDS hierarchy, as set out in the SRFA report.

Infiltration techniques are unlikely to be feasible, due to the proximity to the Medina and the seasonally impacted soils.

The greenfield runoff rate should be determined for the site using current best practice. This will allow for the appropriate sizing of attenuation and

conveyance SuDS to ensure that sufficient space for drainage infrastructure is provided in developing site masterplans.


isle of wight level 2 sfra (2018) · 2018-11-30 · sfra when the level 2 sfra is making...

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