Review of Alternative Sites
for:
Slate Meadow, Bourne End, High Wycombe
Prepared on behalf of
Croudace Homes, Avant Homes & High Wycombe District Council
September 2016 Prepared by Kember Loudon Williams Slate Meadow, Bourne End Sequential Test – D9
REVIEW OF ALTERNATIVE SITES
PREPARED FOR
CROUDACE HOMES, AVANT HOMES & HIGH WYCOMBE DISTRICT COUNCIL
LAND AT SLATE MEADOW, BOURNE END, BUCKINGHAMSHIRE
WITHIN THE DISTRICT OF HIGH WYCOMBE
Kember Loudon Williams LLP, Ridgers Barn, Bunny Lane, Eridge, Nr. Tunbridge Wells, Kent, TN3 9HA.
Tel: 01892 750018 Ref: KLW/14/0043 E-Mail: [email protected] Date: September 2016 2 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9
CONTENTS
1.0 Introduction ……………………………………………………………………………… 4
2.0 Slate Meadow and Environs …………………………………………………………... 6
(i) Site and Characteristics (ii) Sustainability – Key Indicators (iii) Water Environment (iv) Slate Meadow – Realising the Potential
3.0 Planning Policy Position ………………………………………………………………. 17
(i) National Planning Policy on Flood Risk (NPPF) (ii) High Wycombe District Council Policy Position
- Development Plan - Slate Meadow and the Reserve Sites - Housing Land Supply Position - Flood Risk Sequential Test Background Paper - Strategic Flood Risk Assessment
4.0 Scope of Assessment …………………………………………………………………. 28
(i) Need for Sequential Test (ii) Geographical Test Area and Methodology
5.0 Available Sites and Sequential Assessment .………………………………………. 31
- All Available Sites - HELAA - Potential Comparable sites for Sequential Consideration
6.0 Sequential Test and Exceptions Test ………………………………………………. 40
7.0 Conclusion …………………………………………………………………………….. 45
Figures: Figure 1 Slate Meadow and its Context Figure 2 Environment Agency Flood Predictions Figure 3 Predicated Peak Flow Depths – 100 year + 35% Figure 4 District Wide Local Plan (June 2016 Consultation) Housing Delivery Figure 5 Slate Meadow – Areas of Control Figure 6 Flood Zone Classifications for Slate Meadow Figure 7 Slate Meadow and the Reserve Sites Figure 8 Extract from SFRA 2014 centred on Slate Meadow
Appendices: App’ 1 Sustainability Appraisal Plan Extracts App’ 2 Environment Agency Review and Acceptance of Flood Model App’ 3 Extracts from NPPG – Definitions App’ 4 Extracts from Site Delivery and Allocations Supporting Document 2012 App’ 5 Extracts from Site Delivery and Allocations Supporting Document 2012 App’ 6 Draft Local Plan 2016 – Proposed Housing Sites
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1.0 INTRODUCTION
1.1 This report has been prepared by Kember Loudon Williams LLP, on behalf of Avant Homes and Croudace Homes, to review the merits of the land at Slate Meadow, Bourne End for a residential end use against the sequential flood risk testing regime and a review of alternative sites and options. This sequential test has been prepared against the backdrop of the preparation of a development brief and will, ultimately, accompany a full planning application to Wycombe District Council for the erection of up to 170 new homes on Slate Meadow. The site extends to 10.94 hectares. The majority of the land lies within Flood Zones 1, with a smaller area in zone 2 and a very small pocket within flood zone 3a.
1.2 The report has been prepared with the benefit of technical and specialist input from HR Wallingford and High Wycombe District Council. The assessment forms part of a wider suite of documents, including a site wide development brief and masterplan, that have been prepared to support the early release of Slate Meadow for the provision of new homes. The site is one of five ‘reserve sites’ that have historically been excluded or removed from the Green Belt and treated as land safeguarded to meet future development needs. A combination of increased pressure for new housing and the Council being unable to demonstrate a five-year supply of land for housing has heightened the need and importance of delivering new homes on the ground in the short term – in fulfillment of the land having been removed from the Green Belt some 15 years prior. Wycombe District Council’s Cabinet formally sanctioned the release of Slate Meadow for housing on 17th November 2014.
1.3 A joint-working delivery strategy has been established between Avant Homes, Croudace Homes and the Council. Working practices are framed through a binding Planning Performance Agreement - formally signed by all three parties on 21st September and 5th October 2015. The resultant working group, established to realize the potential of the site, has made great strides in the preparation of a site wide masterplan and development framework.
1.4 It has come to light through this process that, despite the identification of Slate Meadow and the setting aside of the land for development for over 15 years in successive iterations of the Council’s development plan documents, an up to date assessment of the sequential merits of the site (in flood risk terms) in relation to other available housing sites within the District is needed to underpin the preparation of the development brief and to support the delivery of new homes on the site. The aim of the Sequential Approach is to direct developments to land with a low risk of flooding. In view of this, this report considers a variety of factors, including the future needs for development for housing, land and potential sites, within a defined area. In this case this is District wide. The sequential test also considers the flood zones and other constraints –
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such as environmental and land use designations. These will often influence the suitability of other potential sites that are comparable in scale and location to Slate Meadow.
1.5 The Sequential Test is usually carried out by the Local Planning Authority as part of the preparation of its development plans and land use planning policy documents. The test is informed by the local Strategic Flood Risk Assessment, which uses flood zone information provided by the Environment Agency (EA) as a starting point for assessment. Against this context the report compares all reasonably available sites with Slate Meadow to establish whether there are any more suitable locations in flood risk terms having regard to the wider environmental, planning and sustainability benefits of each site and wider, demonstrable, need for the Council to deliver new homes as a matter of urgency.
1.6 As a precursor to this, the statement details the national planning policy position on flood risk before reviewing the development plan for the District, including the historic identification of Slate Meadow and the other reserve sites for development within the adopted Core Strategy and the emergence of the new District wide Local Plan dated June 2016. Within this context, a synopsis of the Council’s housing land supply position and rates of delivery is presented to set out the importance of housing provision and the delivery of the application site into context. The Council is demonstrably failing to meet its housing targets, which has a direct impact on the need for housing and the importance of realising allocated sites that are deliverable. This is reviewed in the context of the sequential test and has a bearing on the identification of “reasonably available sites.” The latter are identified from a combination of the Delivery and Site Allocations Development Plan 2013, the Council’s Housing and Employment Land Availability Assessment (HELAA), November 2015 and the emerging district wide local plan 2016.
1.7 The HELAA, in particular, presents a comprehensive list of deliverable and developable sites across the District, together with sites ‘requiring further assessment’ and has been employed as the basis of this review.
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2.0 SLATE MEADOW AND ENVIRONS
(i) Site and Characteristics
2.1 Slate Meadow lies between Bourne End and Wooburn, immediately north of the River Wye and south of the former High Wycombe to Maidenhead railway line. The nine-kilometer section of the railway line between High Wycombe and Bourne End was closed in 1970 and is now used as an informal footpath. It provides an important and tangible edge to the north western boundary of the site. The land to the north of the site, beyond the dismantled section of railway line, is steeply sloping and rises to a level some 100 metres AOD to the north of the site. This area is identified as a Local Landscape Area on the steeply sloping hillside. The area comprises open grassland on steeply sloping land with mature hedgerows and fields.
Figure 1: Slate Meadow and its Context
2.2 The combination of rising land to the north and the ‘hard’ edge of the railway line has the effect of containing Slate Meadow, which lies on the flat valley bottom. The River Wye is a significant feature on the southeastern part of the site - it creates a clear boundary between the rest of the site and the grass verge adjacent to Brookbank. The containment of the river and the associated grassland form a green corridor between Brookbank and Stratford Drive and create an attractive feature of the area.
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2.3 Slate Meadow is surrounded by residential development on three sides. To the north east the site is adjoined by medium density ‘estate’ housing, which is serviced off Stratford and Orchard Drives. St Paul’s Church of England Primary School lies directly opposite the site on Stratford Drive. The site is adjoined to the southeast (on the opposite side of Brookbank) by residential areas that exhibit much lower densities and significant tree cover. The areas around Grange Drive and Brookhouse Drive are characterised by larger detached properties set within generous sylvan plots. The south-western boundary of the site adjoins properties that front onto Cores End Road. Here, the character is more varied with some medium to high density housing from the nineteenth century interspersed with more recent high density housing, comprising terraced homes and apartments: most notably in the area of Frank Lunnon Close. More details are set out below.
(ii) Sustainable Advantage
The Government’s guiding principles, set out within the NPPF, are framed with a clear and unequivocal emphasis on the need for the delivery of key facilities and services including, in particular, the provision of new homes to be underpinned by the principles of sustainability. Achieving sustainable development is arguably, therefore, the most important goal of the planning system. In view of this, an integral and important part of this sequential test is to review the sustainable credentials of Slate Meadow.
Whilst the proposals for the provision of up to 170 new homes have been carefully developed with the Council through the Planning Performance Agreement Process to ensure that the development platform of the site is exclusively within the sequentially preferential Flood Zone 1 land, it is acknowledged that parts of the western fringe of the site lie within flood zone 2. A small, triangulated parcel of land in the south western corner of the site lies within flood zone 3a. In view of this it is important that the sustainability merits of the site are considered in order that an holistic assessment can be made of the site. The NPPF advises that whilst flood risk and its amelioration are material planning considerations, any impacts must be weighed in the round against other interests of acknowledged importance.
A sustainability appraisal has been undertaken of the site. The following presents a synopsis of findings within the key areas of: Highways and Movement, Landscape and Visual, Ecology, Social and Community and Economic considerations. The synopsis should be read in parallel with the plans and diagrams included as Appendix 1.
Highways & Movement: Slate Meadow lies six miles south-east of High Wycombe, between Bourne End and Wooburn Green. There are two pairs of bus stops (inbound and outbound) on Brookbank and Town Lane. One set of these bus stops is directly to the south of the site, with
7 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9 the other lying to the east of Stratford Drive. These stops are served by the following bus routes: Route 1: High Wycombe – Woodbourn Green – Bourne End and Route 1B: Bourne End - Wycombe Marsh, with 13 buses per day, Route 317: Maidenhead - Bourne End – High Wycombe, with 24 buses per day, Route 35: Bourne End - High Wycombe, with 5 buses per day (bpd) (evenings only). There is another pair of bus stops on Cores End Road near Willows Road, also served by bus routes 1 and 317
The site is located approximately 1km from Bourne End Rail Station. The station is a branch line with the following services: one train every thirty minutes to Maidenhead during peak hours and then one per hour, and one train every thirty minutes to Marlow during peak hours and then one per hour.
The adjoining highway to the south, Brookbank, has a carriageway width of 7.1 metres and a 2 metre wide footway along its northern side. There is no footway along the southern side between Kiln Lane and Grange Drive. Cores End Road to the west is narrow with a carriageway width of 5.1 metres and sub-standard footways of around 1.0 - 1.2 metres in width. There is a public footpath from Cores End Road going north towards Willows Road, near the site.
Slate Meadow is relatively flat with hills rising from the northern end. There is no significant level difference between Brookbank and the site. The existing bridged entrance to Stratford Drive from Brookbank will provide the main access. This bridge is 6m wide at its narrowest point. The Brookbank/Stratford Drive junction is a T-junction with a Give Way control and a right turn reservoir provided on Brookbank. It was observed that due to relatively high through flows along Brookbank, queues could form on Stratford Drive during busy periods. Parked vehicles on Stratford Drive exacerbate this issue. The Brookbank/Cores End Road junction currently takes the form of a mini roundabout.
A secondary access is feasible for a limited number of homes via Frank Lunnon Close, off Cores End Road. Given that Cores End Road is narrow and busy, it is likely that if a secondary access was provided to the site via Frank Lunnon Close, it may have to be a left-turn in only vehicle access and/or a pedestrian and cycle access only.
There are a number of public rights of way in close proximity to the site. Footpaths adjoin the western edge of the site and the disused railway provides a well-used footpath route along its northern boundary. The latter links the site with the residential and employment areas to the east, the countryside to the north and Bourne End Academy and the town centre to the west. A number of paths run through Slate Meadow. Whilst informal in nature, these ‘desire lines’ will inform and be accommodated within the development of the site.
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In the round, therefore, the land may be served within existing highway infrastructure with minimal remediation work. The site benefits from proximity to a network of available footpaths and established bus and train infrastructure, which together with the central and locational advantages offers a truly sustainable solution in terms of movement.
Landscape & Visual: Slate Meadow is flat comprising three distinct parcels of land, peppered with occasional scrub and small trees. In the main, hedgerows define the boundaries. One identifiable copse lies along the western edge of the site, with hedgerows denoting the ownership boundary towards the woodland between Wye Valley School and the site. The northern land parcel, under the control of High Wycombe District Council, has village green status and will not, therefore, form part of the proposals.
A Local Landscape Area lies to the west of the site. The site lies in the Chilterns River valley character area Z9. The site is overlooked by properties to the northeast and the properties to the east and south are visible, which affects the character of the site such that it has a semi urban character. Beyond the northern boundary, defined by the disused railway line (public footpath), the countryside is open and forms part of the Green Belt. The visual envelope of the site extends some 800m to the west and a similar distance to the southeast over the intervening residential to the upper slopes of the valley side. The visual envelope is contained to the southwest and northeast by buildings.
A small triangular area of land within the north west corner of the site contains a small area of broadleaved woodland. The trees are covered under Tree Preservation Order 27/1989 and will be retained in perpetuity.
The River Wye runs along and defines the southern boundary. Mature trees are found along the southern bank with a concentration at the south-western corner. Larger shrubs and hedgerows marking the pedestrian footpath define the northern boundary. It is considered that the site has a low to moderate visual sensitivity because of its visual relationship with the urban area and the presence of built development on three sides of the site. Overall the landscape quality of the site is limited.
Ecology: Slate Meadow is not subject to any nature conservation designations nor are there any within two kilometers of the site. Some of the field boundaries are mature and include a mix of mature broadleaf trees, shrubs and other plants, particularly along the disused railway line. The majority of the site consists of semi-improved grassland with small areas of scrub encroachment and tree saplings. There are two recently planted poor species hedgerows within the site.
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Social & Community: The commercial hub and focus of Bourne End lies just under 1 km to the west of the site. The community hall and public library are located within the centre of Bourne End. These facilities, along with a variety of health care facilities are readily accessible from the site on foot. The same is true of retail facilities in the centre.
A total of five schools lie within 2 kms of the site. These include four Primary Schools: Claytons Primary School and Nursery, Westfield School (children with behavioral, social and emotional difficulties – ‘BSED’), St Paul’s C of E School and The Meadow School. St Paul’s adjoins the site to the east with access directly off Stratford Drive. Wye Valley School is a Secondary College accommodating 762 pupils aged 11 – 18 and lies 0.5 kms to the north west of the site.
The closest playing field is within 500 metres, just beside Wye Valley School. Open countryside adjoins the playing field to the north. A Public Footpath provides access to other recreation facilities such as Wooburn Park. The park is within 1 km of the site, along with two other recreation grounds in the same distance.
Economic: The site lies centrally between the four principal employment sites of Soho Mills Industrial Estate, Millboard Industrial Estate, Wessex Road Industrial Estate and Boston Drive Office complex. The former lies 400 metres to the east, of the site with direct pedestrian access along the disused railway line (footpath) on the northern boundary of the site. Small office complexes are located at the corner of the mini roundabout on the south west corner of the site. This links to footpaths leading to the Industrial Estates on Millboard Road and Wessex Industrial Estate (both are within 800 metres of the site). Within the retail core at Bourne End there are business centres, offices and a builder's yard. 1.5 km to the east of the site at Wooburn Green is a secondary retail area with restaurants, pubs, post office, shops and other services.
Detail of Significant Effects (summary): The synopsis above, together with the plans presented within Appendix 1 sets out the sustainable credentials of the site. Within each of the identified indicators Slate Meadow scores highly. There are no negative effects with landscape designations and the ecological interest may be managed and mitigated on site, with improvements to the semi- natural grassland habitat on the village green and the mitigation of ecological interest on the flood zone 2 land on the western side of the site. Slate Meadow has a good relationship, with ease of access on foot, to existing employment, daily shopping and community facilities.
The land is located at the bottom of a hill on a flat field and is surrounded by existing residential development on three sides. The site is well contained, being screened by mature trees and hedging around the site boundary. The sensitive introduction of new homes on the site would
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support further linkages between existing communities and is firmly underpinned by the principles of sustainability.
(iii) The Water Environment
2.4 Slate Meadow lies approximately 700 metres to the north east of the convergence of the River Thames and the River Wye. Whilst there is a history of flooding in the general Bourne End area, this has been remote from the Slate Meadow site and has been attributed to high flow conditions in the River Thames, rather than flows in the River Wye. The latter adjoins the south eastern boundary of Slate Meadow and runs parallel with Brookbank. Whilst flooding occurred in parts of Cores End Road in early 2014, the Section 19 flood investigation report attributes this, at least in part, to insufficient drainage capacity in the local drains and culverts.
Figure 2: Environment Agency Flood Predictions
2.5 The Environment Agency Flood Outline Maps provide a helpful starting point to understand the water environment and to set the various flood events into context for the purposes of this assessment. It is important to bear in mind though, that the flood outline maps are based on an ‘old’ hydraulic model dating back fifteen years to 2001. The model used by the Environment Agency adopts a simplistic approach and lacks the sophistication of contemporary modeling techniques. As a consequence the flood information for Slate Meadow and its surroundings, presented in figure 2 above provides indicative flood predictions only. The predictions understandably take a precautionary approach and as such are not necessarily an accurate reflection of the water regime for the purposes of preparing development proposals.
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2.6 Figure 2 presents the indicative predicted flood profiles (flood Zones 2 and 3) for the River Thames, to the west and south west of the diagram, and the River Wye, centered on Cores End and the southern and western part of Slate Meadow. As depicted, approximately fifty percent of the landmass of Slate Meadow is shown to lie within the flood plain: admittedly within the lesser Flood Zone 2: with a medium probability of flooding. In order to fully understand the flood risks associated with the site and to review its suitability and capacity to deliver new housing, relative to other comparable sites within the District, it is essential that the EA’s indicative flood zone be reviewed and updated with modern modeling techniques. The Agency has already recognized the limitations of its old modeling and its results and is planning to develop a new hydraulic model of the River Wye. However, this work is yet to commence. It is anticipated that results will not be available for perhaps two years or so. Consequently the EA flood map for this area will not be updated – it will remain out of date until that time. The EA is fully aware of this anomaly.
2.7 HR Wallingford has been commissioned to undertake a comprehensive review of the hydrology of the River Wye and its influence on Slate Meadow. A comprehensive hydraulic modeling report has been prepared with the benefit of a previous hydrology study of the area in 2013 (its findings were accepted by the EA), together with more recent river flow information. The model and the associated report have been reviewed by the EA.
Figure 3: Predicated Peak Flow Depths – 100 year + 35% Climate Change
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2.8 In the meantime, HR Wallingford has been commissioned by Croudace Homes and Avant Homes to undertake a comprehensive review of the hydrology of the River Wye and its influence on Slate Meadow. A comprehensive hydraulic modeling report has been prepared with the benefit of a previous hydrology study of the area in 2013 (its findings were accepted by the EA), together with more recent river information. The new model of the river system has been run with flows representing the twenty-year, one hundred year and one thousand year peak period flows. In addition, the one in one hundred year flow has been increased to reflect potential climate change effects. The predicted peak flood depths of the latter (100 year flow + 35% - the “Higher Central” climate change allowance) are presented in figure 3. This shows the flood area for Slate Meadow and its surroundings including, in particular, the Cores End area to the west of the site. It is worthy of note that the one in one thousand year flow is approximately eight percent more than highlighted in figure 3 on page 11.
2.9 The model and the associated report were formally submitted to the Environment Agency for review in June 2016 in accordance with their standard model audit procedures. The Agency confirmed its acceptance of the modeling parameters, methodology and conclusions on 7th September 2016 formally advising that: “…the modelling has been re-reviewed and has been deemed acceptable…” This is significant on a number of levels, namely:
• Sequential Test: For the purposes of sequentially testing the site the new model provides an updated and more accurate basis upon which to review the site and to test its capacity for the delivery of new houses against other comparable sites within the District. The one in one hundred year (plus thirty five percent for climate change) flood profile presented in figure 3 significantly reduces the area of land prone to flood waters when compared with the Environment Agency’s indicative profiles presented in figure 2.
This has obvious implications of the delivery of new homes on the site as the larger proportion of the land under the control of Croudace and Avant demonstrably lies within Flood Zone 1: where it has a low probability of flooding and is suitable for residential development. The facility, therefore, exists to realise the potential of the site and to provide around 170 new homes in a central and demonstrably sustainable location.
• Flood Risk Assessment: The model reviewed and approved by the EA provides the platform to progress and to refine the proposals for Slate Meadow. The careful adjustment of ground levels in the development area could further improve the position by ensuring that there is no increase in flood risk at or near the site. In the fullness of time a Flood Risk Assessment will be prepared for the site and its surroundings. A key
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component of this work will be to ensure that the new homes do not increase the overall flood risk at Slate Meadow or the neighbouring properties. Homes will not be provided in flood zone 3 areas.
2.10 For completeness a copy of the Environment Agency’s response is attached at Appendix 2 of this report. On flood predictions the Agency raises the point of setting the finished floor levels of the new homes. This is noted and will be designed for in any event – all finished floor levels will be set well above the local flood levels. The predicted flood levels in the lower part of the site area do not increase rapidly with increase in flood return period so the provision of a suitable freeboard of a 100 year event with climate change effects, will also provide a substantial freeboard for a 1,000 year flood event. This is very helpful, with the Environment Agency confirming that in practice a high level of protection will be provided to the new properties for the 100-year, 1,000-year and well beyond.
2.11 The Environment Agency’s confirmation that the model is acceptable for modelling the existing regime is welcome in the context of this sequential test. In combination with the flood model it provides a platform to resolve the site and the small parcels of land that fall within flood zone 2. The detailed proposals for Slate Meadow have correctly followed normal practice and provided a freeboard above the peak predicted flood levels, ensuring that the properties are well above the flood levels. This is well in excess of the small changes in predicted flood levels that might be associated with the potential small changes in the ground levels at the river bank that the EA mentions. It also ensures that there is no increase in flood risk for other properties in the area - providing the “conservative approach to the consideration of flood risk” referenced by the Agency.
2.12 Through the Planning Performance Agreement process, consultation will continue with the Environment Agency and local stakeholders, including the Slate Meadow Liaison Group, to ensure that any properties that are built will not be at risk of flooding, and importantly do not cause an increased risk of flooding to neighbouring properties. We understand that further, exploratory work will be undertaken to establish whether, through the process of building new homes on the site, improvements could be made to reduce the existing flood risk in the Cores End area.
2.13 With regard to surface water, any increases in the runoff rates or volumes as a result of the development will be mitigated for through the use of Sustainable Drainage Systems (SuDS) features - such as permeable paving, open surface water storage systems, etc. These facilities will be contained within the development platform. The peak surface water runoff rates following development will be no more than current Greenfield run off rates.
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(iv) Slate Meadow – Realising the Potential
2.14 Slate Meadow, along with four other sites on the edge of High Wycombe, is identified within Policy CS8 of the Council’s adopted Core Strategy as a Reserve Location for Development. This is a long-standing policy, having been carried forward from the adopted Local Plan, 2004. Slate Meadow and the other sites are treated as “land safeguarded to meet future development needs” in circumstances where the demand for new homes exceeds the supply of deliverable sites on previously developed land within urban boundaries. Through a combination of factors, the demand for new homes far outstrips supply and the Council is failing to meet its objectively assessed housing need and to demonstrate a five-year supply of deliverable land for housing. In view of this, the Council’s Cabinet resolved on 20th October 2014 to release all of the reserve sites for housing to help plug the supply gap while work continues on the emerging local plan policy through the preparation of a new District Wide Local Plan.
Figure 4: District Wide Local Plan (June 2016 Consultation Draft) Housing Delivery
2.15 The draft Consultation Document of the Council’s emerging District Wide Local Plan was formally published in June 2016. The ‘new’ plan contains a specific policy allocating Slate Meadow for residential development - policy BE1 identifies the site indicatively for between 150 and 190 dwellings. The land, therefore, forms and important and integral part of a strategic release of land for the provision of housing in the Bourne End and Wooburn catchment area. The site particulars, together with illustrative housing numbers, are presented in figure 4 above.
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Figure 5: Slate Meadow – Areas of Control
The combination of Policy BE1 and the spatial strategy for Bourne End and Wooburn lift Slate Meadow through the hierarchy from reserved site to draft allocation, which is consistent with urgent need for housing within the District
2.16 It is intended to construct up to 170 homes on the site on a combination of the land controlled by Croudace and Avant Homes – figure 5 above refers. The status of the village green (coloured green in figure 5), its location and availability will remain unaltered by the proposals. In view of this and having careful regard to the site wide flood constraint identified in figures 2 and 3 the lion’s share of housing development will be within the south eastern portion of the site: broadly within the area coloured purple and falling within flood zone 1. A small number of houses (approximately 15 in number) will be located on the north western corner of the site. These homes will be accessed from Cores End and will, again, be sited outside the flood plan in flood zone 1.
2.17 The combination of these areas will provide a development platform to accommodate approximately 170 new homes. This quantum of development forms the baseline for this sequential appraisal: there being a natural emphasis on sites that are comparable in size and capable of delivering a similar number of units.
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3.0 PLANNING POLICY POSITION
3.1 The following presents a synopsis of the national and local planning policies that are relevant to flood risk within Wycombe District. The review is not exhaustive. It serves to present the main points for consideration in the sequential testing of Slate Meadow, including a review of alternatives.
(i) National Planning Policy on Flood Risk
3.2 The National Planning Policy Framework (NPPF), March 2012, and the associated National Planning Policy Guidance (NPPG) - now available online - cover the full range of planning issues underpinned by the central ambition of fostering sustainable forms of development. The framework sets out the process by which Local Planning Authorities are to account for flood risk as an integral part of the planning process. The basic Sequential Test requirements and the process remain largely the same as those presented in Planning Policy Statement 25 on Flood Risk (PPS25 – now withdrawn) in terms of the way vulnerable land uses and flood risk is assessed. Generally, development and other planning decisions have to accord with the presumption in favour of sustainable development as set out at paragraph 14 of NPPF.
3.3 Within the NPPF guidance documentation it states: “For individual developments on sites allocated in development plans through the Sequential Test, applicants need not apply the Sequential Test.”
3.4 In this case the Council has determined that whilst the site is safeguarded for future development it is not specifically allocated and so a sequential test is required. Policy DM17 of the adopted Delivery and Site Allocations Development Plan confirms that developments that are in flood zone 2 or 3 and have not been allocated in the Local Plan will only be permitted where it has been demonstrated that there are no other sites available at a lower flood risk zone. In view of this the Council has adopted the position that although Policy CS8 of the Core Strategy, identifies the Slate Meadow as a location for development within the plan period a sequential test will be required. Clearly the nature of “allocation” is a ‘grey area’ in this case. However, and for the avoidance of doubt, this sequential test has been prepared to ensure that Slate Meadow is sequentially tested in accordance with the provisions of the NPPF.
3.5 The overall aims set in the NPPF for the management of flood risk in the preparation of local plans and land-use policies are encapsulated by paragraph 100 as follows:
“Local Plans should apply a sequential, risk-based approach to the location of development to avoid where possible flood risk to people and property and manage any residual risk, taking account of the impacts of climate change, by: 17 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9
• Applying the Sequential Test; • If necessary, applying the Exceptions Test; • Safeguarding land from development that is required for current and future flood management; • Using opportunities offered by new development to reduce the causes and impacts of flooding; and • Where climate change is expected to increase flood risk so that some existing development may not be sustainable in the long-term, seeking opportunities to facilitate the relocation of development, including housing, to more sustainable locations.”
With these ambitions in mind there is a wealth of existing studies on flood risk that this assessment can draw on.
3.6 Generally the approach to a sequential test is that it ensures that areas at little or no risk of flooding are developed in preference to areas at higher risk. As far as possible the aim is, quite rightly, to identify the areas liable to flood, define which land uses are sensitive to flood risk and then to direct development to appropriate locations. For ease of reference figure 6 below presents the flood zone classifications by area for Slate Meadow. This is from work carried out by HR Wallingford and approved by the Environment Agency.
Figure 6: Flood Zone Classifications for Slate Meadow
3.7 Tables 1, 2 and 3 of the NPPF guidance (on line facility) set out the definitions and classifications of the flood zones, definitions of vulnerability in land use terms and flood risk vulnerability classifications respectively. Table 1 defines four flood zones. Zone 1 has the lowest probability of flooding, having less than a 1 in 1000-year annual probability of flooding. Zone 2,
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has a medium probability, having between 1 in 100 year and 1 in 1000 annual probability of river flooding, while Zone 3 (split into a and b) has a high probability of flooding. For completeness the definitions, along with clarification on essential infrastructure, are provided in full at Appendix 3.
3.8 Table 2 sets out a definition of different land uses and development and their vulnerability to flood impacts. The residential end use being sought for Slate Meadow falls within the “More Vulnerable” classification (see Table 2 of Appendix 3). Table 3 in Appendix 3 explains the relationship of the vulnerability of the use and its compatibility to a particular flood zone. The objective is to direct development to Flood Zone 1 in the first instance and only consider other Flood Zone land if necessary to meet development needs. So Flood Zone 1 is deemed suitable for all types of development whether they are classified as highly vulnerable or not. Flood Zone 2 is also deemed suitable for all types of development but for highly vulnerable types of development an Exceptions Test must first be applied. In Flood Zone 3a and 3b certain types of development are precluded all together and for others Exceptions Tests must be applied.
3.9 In this context, and with particular reference to Slate Meadow, it is important to note that:
• The vast majority of the site to be developed is in Flood Zone 1; • Whilst only approximately twenty-five percent of the site is in Flood Zone 2 it is only intended to develop in a very small part of this. The small part of Zone 2 included in the development will be raised well above the 100 year plus climate change and the 1,000 year flood levels; • Although a very small part of the site is in Flood Zone 3a, this will not be built on; • None of the site is in Flood Zone 3b (the functional flood plain, flooding on a 1 in 20 year event); and • Whilst this sequential test has been prepared, the whole approach is to develop on the higher land within Flood Zone 1 – the sequential approach promoted with the guidance.
3.10 Paragraph 102 of the NPPF explains that the Exception Test is a method to demonstrate and ensure that people and property will be managed in relation to their flood risk where Flood Zone 1 and potentially Flood Zone 2 sites are not available as alternatives. In relation to this Exceptions Test it is necessary to first identify the housing development needs of the local authority area as a whole, in this case Wycombe District, and estimate whether all of this development can be contained on land within Flood Zone 1. If this is not possible then it will be necessary to identify whether it is appropriate to identify sites in Flood Zone 2 with lowest risk sites being favoured.
3.11 In summary NPPF is seeking to direct development to sites within areas of lowest flood risk in the first instance (Flood Zone 1). Only if it can be demonstrated that there are no suitable sites within these areas should alternative sites (i.e. within areas that may potentially be at greater
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risk of flooding) be contemplated (seeking sites in Flood Zone 2 and then, failing that, sites in Flood Zone 3), taking account of the vulnerability of the proposed land use – Appendix 3 refers.
3.12 Whilst this hierarchy forms the basis of the sequential assessment, it is very important to place flood risk within the wider planning context. The NPPF covers a wide range of planning issues – not just flooding. In this regard the formulation of planning policy and the allocation of land for future development must also meet the requirements of other material considerations within the NPPF, including inter alia, aspects relating to environmental protection, meeting housing need, economic growth and so on. Wider spatial planning issues and the emphasis on sustainable merit/advantages in locational and movement terms are equally important and, quite rightly, lie at the heart of the current planning system. A synopsis of the key sustainability indicators in relation to Slate Meadow is presented within Section 2.0.
3.13 This is particularly relevant in the case of High Wycombe with its heavily constrained rural environment, much of it forming part of the Chilterns Area of Outstanding Natural Beauty and/or the Metropolitan Green Belt – each has long standing presumptions against development. Alongside this, of course, is the urgent and demonstrable need to provide new homes to meet identified current housing need and growth targets to 2033. The lack of housing supply is particularly acute within Wycombe District. The Council’s five-year housing land supply is 3.8 years based on the latest 5-year supply and 2015 assessment. Significantly, this does not take account of the shortfall against the most up to date information within the Council’s objectively assessed housing need requirement in its emerging plan to cover the period of the emerging District Wide Plan to 2033. This ratchets the delivery requirement even higher and is considered further in Section 5.0.
3.14 In the round, therefore, the provision of sustainable forms of development requires the balancing of a wide range of social, economic and environmental factors – all of them, along with managing the water environment, important.
(ii) High Wycombe District Council Policy Position
The Development Plan
3.15 Presently, local planning policy in Wycombe District is broadly covered by:
• The Core Strategy (2008); • The Delivery and Site Allocations Plan (2013); and • The remaining ‘saved’ policies from the Local Plan (2004).
3.16 Wycombe District Council is also in the process of producing a ‘new’ district wide Local Plan that will replace the saved policies of the 2004 adopted Local Plan and Core Strategy, 2008. 20 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9
The existing policies of the Plans noted above include policies, which govern the location of new development and seek to avoid areas of flood risk for new development unless the risk of flooding can be reduced and/or the wider sustainable benefits outweigh the identified harm. Core Strategy policies CS2 (Main Principles for Development) and CS 18 (Waste/Natural Resources and Pollution) are particularly relevant in these terms. The latter requires proposals for new development to ‘avoid increasing risks of or from flooding, including fluvial flooding, sewer flooding, surface water flooding and groundwater flooding..’.
3.17 Policy CS8 of the Core Strategy is a long-standing interpretation of Council policy that identifies reserve locations for future development. The parcels of land, including Slate Meadow, have long been excluded from the Green Belt to meet future development needs – the sites are identified in figure 5. The Council’s Cabinet meeting on 20th October 2014 approved the release of all of the reserve sites to assist in delivering housing to contribute towards making up the shortfall in the Council’s rolling five year housing land supply.
3.18 The adopted Delivery and Site Allocations Plan includes Policy DM17, Planning for Flood Risk Management’, which seeks to manage development within flood risk zones 2 and 3 by reference to a sequential assessment and the exceptions test unless otherwise allocated for specific development – referenced above. Specifically, the policy confirms that development will be permitted where it has been demonstrated that ‘..there are no other sites available in a lower flood risk zone as a result of sequential assessment… and that the requirements of the exceptions test as set out in national policy have been met…’
Figure7: Slate Meadow & the Reserve Sites
3.19 High Wycombe District Council has produced a series of reports relating to strategic flood risk assessment and its emerging Local Plan. These provide a useful starting point for this review.
Draft Wycombe District Local Plan June 2016
3.20 The District Council recently published its draft Local Plan for consultation purposes. In that Plan it explained a need to deliver 15,100 homes between 2013 and 2033. This equates to 750 new homes per year – significantly greater than the current delivery rate of 450 homes per year. The Policy aims to deliver 10,000 homes within High Wycombe District and a further 5000
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homes in neighbouring Aylesbury Vale District. Of the homes within High Wycombe, 750 new homes are expected to be located at Bourne End and Wooburn, 5,250 at High Wycombe, 2,600 homes at Princes Risborough, 300 homes at Marlow and 1,100 homes within the rural areas (draft Policy CP4 refers). Table 2 overleaf presents a summary of the sources of the Council’s housing supply.
3.21 A combination of the details contained within Appendix 6 and Section 5.0 of this report set out the areas where development is to occur. Importantly, Slate Meadow is proposed to be elevated from safeguarded site to a residential housing allocation. The net supply of new homes is to be broken down in accordance with table 2 overleaf.
Aylesbury Vale District Council – Emerging Local Plan
3.22 Aylesbury Vale, the adjoining administrative district to the north, is also in the early stages of preparing a district wide local plan to cover the period 2013 to 2033. The first consultation exercise under Regulation 18 is programmed between July and September 2016. The Consultation Draft of the Local Plan includes proposals for some 33,300 new dwellings across the district of Aylesbury Vale. This includes the provision of 5,000 new homes contained within High Wycombe District Council’s objectively assessed needs – this requirement has been addressed through the duty to co-operate. The draft Local Plan is programmed for submission to the Inspectorate in March 2017 with a view to adoption later that year. Consequently, the plan is at a very early stage in its preparation and little material weight can be attached to it.
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The plan will pass through a number of rounds of local authority review, before proceeding to examination and perhaps, thereafter, modification.
3.23 Interestingly, and perhaps unsurprisingly, there has been a substantial body of opposition from the communities of Aylesbury Vale against accommodating some 5,000 houses from High Wycombe District Council’s objectively assessed housing need. It is anticipated, therefore, that the planned decampment of housing will be the subject of further review and be subject to the rigours of public scrutiny through the Examination process.
Wycombe District Housing Land Supply Position
3.24 As stated above the provisions of the NPPF and the range of planning issues are far-reaching and is not limited to the water environment and flood risk: particularly given the growth figures for High Wycombe and Aylesbury Vale districts. There is a natural tension between the acknowledged importance of directing development towards areas with the lowest probability of flooding and the need to deliver new homes to meet growth targets in areas that are centrally located and benefit from sustainable advantage. In view of this and in order to provide a context for this sequential test, it is necessary first; to consider the strategic housing land availability assessments and the Council’s objectively assessed housing need, relative to housing delivery. It is the combination of these assessments/studies that underpin the quantum of housing that is demonstrably required to meet the provisions of the adopted Core Strategy and, now those, of the emerging District Wide Local Plan.
3.25 The High Wycombe Core Strategy was adopted in July 2008 and establishes the framework and spatial strategy for the delivery of development within the District to 2026. The Strategy identifies 8,050 new homes during this period – based on the provisions of the South East Plan. As established, Slate Meadow site is identified as a reserve location for future development alongside four other safeguarded/reserve sites. More recently, the adoption of the Council’s Delivery and Site Allocations Plan in July 2013 interpreted the provision of the Core Strategy and allocated land and sites necessary to deliver 8,050 new homes by 2026.
3.26 However, in response to the changes made at national level and the change in emphasis towards the growth agenda and sustainable forms of development within the NPPF, the Council published its draft Local Plan in June 2016. This Plan established an objectively assessed housing need of 15,100 new homes between 2013 and 2033. Of the 15,000 houses the draft plan makes provision for some 10,000 homes to be allocated within the District – the allocation includes the Slate Meadow site. It is anticipated that Aylesbury Vale will accommodate the residual, although as stated earlier there are now serious question marks
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over this strategy and the quantum of housing that can/will be provided within the adjoining district.
3.27 The evidence base for this draft Plan includes the Housing and Economic Land Availability Assessment (HELAA), dated November 2015. The HELLA identifies some 9,100 dwellings as a potential housing land supply. Significantly, in this context, this figure also includes the release and delivery of the reserve sites for housing and includes Slate Meadow. As a consequence, and in the absence of an adopted Plan to deliver both the 10,000 homes earmarked for High Wycombe District and the 5,000 homes identified to meet High Wycombe’s need within Aylesbury Vale District, Wycombe District Council still cannot demonstrate a 5 year housing land supply. This is a mimimum requirement under the provisions of the NPPF. Paragraph 47 refers and highlights the need to make provision for an additional buffer of 5% to support choice.
3.28 In November 2015, the Council published its 5-year housing land supply assessment. The assessment concluded that the Council could only deliver sites totaling 3,642 houses - equivalent to 3.8-years’ worth of housing land supply. To meet the requisite minimum five-year period of supply of some 4,756 dwellings is required. Consequently the report concludes that ‘..a five year supply cannot currently be demonstrated in Wycombe District when assessed against the objectively assessed need..’. This is now substantially out of date and the 5-year housing land undersupply continues to be serious.
3.29 It is an unfortunate reality that this position of undersupply of housing and growth (in terms of the immediate 5-year supply horizon and the objectively assessed need during the new Local Plan period) provides the backdrop to this sequential test for Slate Meadow. In brief the wider issues of planning delivery and the Government’s unwaivering commitment to the growth agenda, particularly in housing provision, weigh heavily in favour of the urgent release of Slate Meadow for housing. The Council too, is in full agreement on the need to release the site as a matter of urgency.
Flood Risk Sequential Test Background Paper
3.30 The Council’s background paper relating to the flood risk sequential test sets out the methodology and sequential test relating to proposed site allocations in the Delivery and Site Allocations Plan (June 2012). The paper updates an earlier version from 2009. The Delivery and Site Allocations Plan focuses mainly on the town centres of High Wycombe, Marlow and
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Princes Risborough and so the assessment is specific to those areas. The Background Paper concluded that the Delivery and Site Allocations (DSA) sites:
• HWTC10, Swan Frontage, High Wycombe; • HWTC15, Collins House and Corner of Bridge Street/Desborough Road; • HWTC16, Oxford Road Roundabout; • HWTC17, Bridge Street, High Wycombe; • HWTC18, Baker Street, High Wycombe, and a small part of; • HTWC8, Council Offices and Royal Mail sorting Office
were within Flood Zone 2 but in relation to sites within Marlow and Princes Risborough the allocations were outside Flood zone 2 and 3. The paper concluded that 20% of the High Wycombe sites were located in higher flood risk zones (Zones 2 and 3). Whilst some of the sites delivered a mix of uses including residential uses their allocation was necessary to deliver Core Strategy objectives.
3.31 Again, the need to find an appropriate planning balance between the management of flood risk and the demonstrable need to accommodate housing and economic growth has, quite rightly, come to the fore.
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Strategic Flood Risk Assessment
3.32 The consultancy, Jacobs, updated the Level 1 Strategic Flood Risk Assessment (SFRA) in November 2014 on behalf of the District Council. It is noted that the flood mapping used in the SFRA was updated prior to the new SFRA, but the changes were small. It is stated, “none of these changes occur within the allocated development sites in the Delivery and Site Allocations Plan (DSAP).” Whilst an update, the findings do not therefore invalidate the conclusion of the 2009 Sequential Test. Amongst other things, the conclusions of this test clearly state that there is a need to progress all of the Flood Zone 2 sites, including Slate Meadow.
Figure 8 – Extract from SFRA 2014 centered on Slate Meadow
3.33 The SFRA requires all sources of flooding to be considered. In particular this will mean the potential for pluvial (surface water) flooding. Whilst there is some potential flooding shown on the EA pluvial flood map in the Slate Meadow area this is in similar areas to the fluvial flooding. As such its impact will be comparatively limited on the overall site and will be considered in more detail as part of the site layout development process and any mitigation presented within the site-specific Flood Risk Assessment. Surface waters are likely to be accommodated through on-site SuDS. Calculations will be undertaken at the right time to
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ensure that the storage and management of surface waters is controlled to best effect - this work is being undertaken by HR Wallingford.
3.34 The November 2014 SFRA mapped the areas within Wycombe District that have a low, medium and high probability of fluvial flooding. The full extent of the Bourne End/Wooburn Flood Zone is presented within figure 8 on page 25. The area coloured turquoise on Slate Meadow, aligns with flood zone 2, and is based on the Environment Agency’s flood maps and how these would alter with climate change. The purpose of the document was to support the housing delivery strategy in the emerging Local Plan. It is important to note though, that the Jacobs 2014 update and its associated mapping were carried out prior to the HR Wallingford modeling. Whilst the Jacobs mapping is useful information it is important to recognize that the flood extents shown are not accurate. In view of this the SFRA is useful only as background information.
3.35 The work undertaken by HR Wallingford this year (set and out in sections 2 and 3 of this report) as accepted by the Environment Agency, contains more up-to-date and accurate information. This work can and should form the basis of reliance.
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4.0 SCOPE OF ASSESSMENT
Need for Sequential Test
4.1 Wycombe District Council have determined that a sequential test is necessary despite the site being identified as a Reserve site, under the adopted Local Plan 2004 and more recently under Policy CS8 of the Core Strategy.
4.2 This sequential test examines whether there is an opportunity for the residential development to be carried out on an alternative site that is less susceptible to flooding. This approach needs to be set against the overarching objectives of sustainable development and the need to meet objectively assessed housing needs laid down in NPPF and presented in earlier sections of this report.
4.3 The vast majority of the Slate Meadow site is located within Flood Zone 1. The wider area comprising the village green on the north eastern portion of the site and, below it, the substantial grazing paddocks bounded by the River Wye to the south and Stratford Drive to the east lie within flood zone 1. Parts of the linear parcel of land to the west (running approximately north/south) and controlled by Croudace Homes currently fall within Flood Zone 2. Figure 6 presents the land classification: flood zone 2 is presented in green. In any areas where small parcels of land stray into the zone 2 classification these will be carefully engineered to become Flood Zone 1.
4.4 The built residential part of the site, which is defined as ‘more vulnerable’ will be located solely within Flood Zone 1: subject to the re-engineering referenced above. A small, triangulated parcel of land in the south west corner of the site (coloured orange in Figure 6) - amounting to approximately two percent of the land area - falls within flood zone 3a. This area will be unaffected by the proposals. If it is accepted that all the necessary built residential development can be accommodated within Flood Zone 1, then it is not necessary to pursue the sequential test any further.
4.5 If the Council considers that the small area of re-engineered and re-graded Flood Zone 2 land ought to be considered in the sequential test, then the assessment of sites outlined below demonstrates that some housing located within Flood Zone 2 within the District as a whole is essential in delivering the much needed housing identified in the Objectively Assessed Need. On this basis it is the case that both Flood Zone 1 and some Flood Zone 2 land is necessary to deliver the housing growth agenda in High Wycombe. The Slate Meadow site, with only a small proportion of Zone 2 land, therefore, ought to be considered favourably in this regard.
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This is consistent with the joint working arrangements between Wycombe District Council, Croudace Homes and Avant Homes through the Planning Performance Agreement process.
4.6 The fact that a small triangular pocket of the wider site is described as Flood Zone 3a (orange land within figure 6) is not considered material to the sequential test. This area is restricted to the south western corner of the site and some way distant from the planned location/siting of the new homes of zone 1 land to the north and east. No housing is proposed on this area and, as such, there should not be a need to move the assessment towards the Exceptions Test. However, and for the avoidance of doubt the exceptions test has been applied in Section 6.0.
4.7 It is important to note that locations for more vulnerable development such as housing within Flood Zone 3 can still be considered as appropriate if they meet the Exceptions Test.
Geographical Test Area and Methodology
4.8 Agreement has been reached that the ‘search area’ for the sequential test should cover the whole of Wycombe District. The District is located to the North West of London, within Buckinghamshire. The main rivers running through the District are the River Thames and River Wye together with its associated tributaries. The Wye runs parallel with the southern boundary of the site between it and Brookbank.
4.9 The main urban centre and built up area is High Wycombe but there are other settlements including Marlow and Prince Risborough nearby. The outlying villages are generally modest settlements that are not of a sufficient scale or population to support significant development. They also lack the requisite levels of public transport infrastructure, retail, employment and community/social infrastructure to support (and sustainably justify) comparable levels of growth to that planned for Slate Meadow.
Site Search Methodology
4.10 The aim of the site search is to identify ‘reasonably available’ residential sites that, due to their location and characteristics are sequentially favourable in flood risk terms (Flood Zone 1). The development proposals are for a ‘more vulnerable’ residential use. In view of this the assessment will examine the available sites identified either as housing allocations or sites, which are identified as being available within the HELAA document, together with those in the emerging draft Local Plan. The combination will be used to establish whether there is scope to choose Flood Zone 1 sites only, as viable and deliverable alternatives to Slate Meadow. This ties in with the aims of NPPF. Setting aside the identification of the site as a Reserve site, and its allocation for 150 – 190 new homes in the emerging District Plan, the NPPF seeks to direct new development to areas with the least possible risk of flooding. This is generally appropriate 29 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9
subject to the wider considerations of whether alternative sites are sustainable in other respects and are not encumbered by landscape, ecological or other land use designations or constraints that would render the site unsuitable for development.
4.11 The wider assessment criteria used when comparing sites is provided below. This is based on Environment Agency (EA) guidance and that found in the NPPF.
• Whether flood risk on the reasonably available alternative site options is higher or lower than the application site? Only sites with lower or equal flood risk probability can be considered as genuine alternative sites; • The policy status of each site? Whether reasonably available options being considered are allocated within the development plan or have been identified in the HELAA as suitable, and available sites that might come forward in the emerging Local Plan. • The approximate capacity/residential yield of each reasonable available site being considered; • Sustainability credentials of each available site; and • Details of any constraints to the delivery of the identified reasonably available options. For example, availability, lack of appropriate infrastructure, access issues etc.
The Environment Agency Flood Maps and the previous Strategic Flood Risk Assessment work will be assessed to identify the level of flood risk on a particular site.
4.12 Based on these criteria, there are three stages to the appraisal process, namely: (i) to identify available sites, (ii) to discount sites that do not meet relevant assessment criteria, and, (iii) to compare the remaining sites against Slate Meadow having regard to flood risk and the wider planning and sustainability considerations.
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5.0 AVAILABLE SITES AND SEQUENTIAL ASSESSMENT
5.1 Available evidence sources were considered to support the initial process of site identification – inter alia these included the Council’s adopted Local Plan, the Core Strategy, the Delivery Site Allocation Document, the Housing and Economic Land Availability Assessment (HELAA) and the recently published draft Local Plan June 2016.
5.2 The most current and up-to-date documents are the HELAA - dated November 2015 and the draft High Wycombe Local Plan 2016. The latter presents a comprehensive strategic appraisal of all potential housing, economic and retail sites within Wycombe District, while the former, the HELAA, presents a district wide picture of the availability and suitability of land for development. The document forms an important and fundamental part of the evidence base for the preparation of the new Local Plan for the period 2013 – 2033. In the context of this sequential test, therefore, the HELAA covers the relevant period of time and the full geographical extent of the District: two key areas of scope agreed with the Council at the outset.
5.3 The land availability assessment includes Appendices that set out sites under construction, sites with planning permission but not yet implemented (which may or may not include sites that are also allocated for housing) and other deliverable sites that are allocated in the Delivery and Site Allocation Plan 2013. The document also identifies ‘other deliverable sites’ that are not allocated, but are worthy of further consideration. This document, therefore, provides an up-to-date district wide baseline to identify all available sites to be considered against the provisions of the sequential test. Extracts from the Draft Local Plan 2016, including those sites being promoted for development, are addressed later in this section.
Housing and Economic Land Availability Assessment
5.4 The HELAA identifies the full extent of land and sites that are available across the district. In this context, paragraph 1.8 of the document confirms that ‘…whilst the HELAA must be grounded in reality (sites must be realistic and viable), nonetheless its key role is to identify the volume and geography of potential supply..’. In view this, and given that the appraisal is only nine months old, the HELAA identifies those ‘current’ sites that ought to be considered in this appraisal and forms the point of departure for the sequential test.
5.5 The scope of assessment within the HELAA (presented within tables 1 – 18 of Appendices 2 - 6 of the document) includes an appraisal of flood risk and surface water issues for each of the identified sites. Considering this evidence alongside the survey data contained in the Flood
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Risk Sequential Test Background paper, November 2009, and the Council’s Delivery and Site Allocations Plan Supporting Document (CD3.5.3) provides a useful baseline for the sequential test and is helpful in establishing the position of Slate Meadow within the sequential hierarchy. Relevant extracts of flood risk maps are provided in Appendix 2 of the HELAA.
5.6 Table 9 of Appendix 2 of the HELAA identifies sites under construction. These amount to 1,057 units, net. On the basis that these developments benefit from extant planning permissions and are ‘under construction’ they fall beyond the scope of the sequential test and do not need to be assessed here.
5.7 Table 10 and parts of Table 11, also within Appendix 2 of the HELAA, identify sites with non implemented planning permissions (5 dwellings or more), planning applications pending or schemes that are likely to be resubmitted to overcome planning issues. The combination of these sites generate a total of 700 net additional dwellings for those unimplemented permissions in Table 10 and 1,846 net additional dwellings for the other sites – total 2546 homes. On the basis that these sites benefit from extant planning permissions they too, should not be considered as part of the sequential test - permission has been granted and implementation can occur irrespective of the matters under consideration in this report.
5.8 ‘Other deliverable sites’ are identified within Table 11 of Appendix 2 of the HELAA. These parcels of land are those that are likely to come forward within a period of five-years and can provide five dwellings or more. Some have the benefit of planning permission and so have not been considered. The remaining sites that have been assessed are a combination of those, which appear in the Delivery Site Allocations Plan 2013, the Adopted Core Strategy 2008 and the draft district wide Local Plan 2016. These parcels of land ought to be considered in this sequential test and are set out in tabulated form below by reference to location, yield (expressed by number of dwellings) and flood zone classification:
Site Reference Location Flood Zone SHW0323 Lilys Walk (240 dwellings) Zone 1 SHW0339 Collins House/32 Bridge St (47 Zone 1 dwellings) SMA0068 Portlands Gardens, Marlow (73 Zone 1 dwellings) SHW0421 Netley Works, Queens Rd, High Zone 1 Wycombe (11 dwellings) SHW0408 RAF Daws Hill Lane, High Zone 1 Wycombe (214 dwellings)
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Site Reference Location Flood Zone SBE0033 Slate Meadow, Bourne End (160 Zone 1 and 2 (if the dwellings) re-engineered area is deemed not to become zone 1 land) SHW0004 Gomm Valley, High Wycombe Zone 1 (200 dwellings) SHW0283 Terriers Farm, Kingshill Road, Zone 1 High Wycombe (250 dwellings) SHW0429 Abbey Barn South, High Zone 1 Wycombe (160 dwellings) SHW0428 Abbey Barn North, High Zone 1 Wycombe (75 dwellings) SWC0067 Ashwell’s Field, Cock Lane, High Zone 1 Wycombe (95 dwellings)
Other Sites – 6 – 10 year Horizon
5.9 Table 12 of Appendix 2 of the HELAA lists further ‘Developable Sites’ within the longer 6-10 year horizon. Whilst some of these sites are small (yield highlighted by reference to dwelling numbers) and not comparable with Slate Meadow (150 – 190 new homes) it is considered that they should be reviewed in relation to whether they are sequentially preferable. Whilst some of these sites may not come forward, it provides a review of the potential.
Site Reference Location Flood Zone SBE0050 Windrush House, Bourne End (12 Zone 1 dwellings) SHW0337 Baker Street Car Park, Baker Street, Zone 2 (90%) High Wycombe (96 dwellings) SHW0390 Westwood, High Wycombe (45 Zone 1 dwellings) SHW0436 Garages between Chiltern Avenue and Zone 1 Rutland Avenue, High Wycombe (10 dwellings) SHW0526 Garages at Havenfield Road, High Zone 1
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Wycombe (5 dwellings) SHW0584 1-9 Shaftesbury Street, High Wycombe Zone 1 (9 dwellings) SHW0600 27 High Street, High Wycombe (9 Zone 1 dwellings) SHW0589 7-8 High Street, High Wycombe (14 Zone 1 dwellings) SLW0028 Queensmead House, Queensmead Zone 1 Road, Loudwater (25 dwellings) SPR0051 BCC Highways Depot, Corporation Zone 1 Yard, Longwick Road, Princes Risborough. (7 dwellings) SPR0023 Whiteleaf, Picts Lane, Princes Zone 1 (remainder) Risborough (84 dwellings) SPR0054 Land Fronting New Road, Princes Zone 1 Risborough 8 dwellings) SWB0021 Lincoln House, Wooburn Green (20 Zone 1 dwellings) SFH0018 Hughes Builders Merchants, Rear of Zone 1 26-30 Whitepit Lane, Flackwell Heath (6 dwellings) SHW0020 Dashwood Avenue, High Wycombe Some surface water (25 dwellings) flooding SHW0210 34 Dashwood Avenue High Wycombe Some surface water (5 dwellings) flooding SHW0325 Buckingham House and Castle House, Zone 1 West End Road, High Wycombe (46 dwellings) SHW0402 Frank Hudson Furniture Factory, Most of site subject to Rosebery Avenue, High Wycombe (10 surface water dwellings) flooding SHW0406 Ogilvie Road, High Wycombe (9 Zone 1 dwellings) SHW0419 JC and MP Smith, Princes Gate (also Zone 1 known as Rickett Road, Ryedale), High Wycombe (5 dwellings) SHW0440 Brook Street, High Wycombe (10 Zone 1
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dwellings) SHW0524 Remainder of Leigh Street Zone 1 Employment Area (54 dwellings) SPR0032 Hypnos, Pict's Lane, Princes Zone 1 Risborough (90 dwellings) SWC0082 Westhorpe House, Westhorpe Park, Zone 1 Little Marlow (12 dwellings) SHW0400 Longland Way / Pettifer Way (South) Zone 1 (previously known as Flats off Chairborough Road) (35 dwellings) SHW0466 Garages at Tyzack Road, High Zone 1 Wycombe (6 dwellings) SHW0565 Burrows House, Jubilee Road Downley Potential surface High Wycombe (25 dwellings) water flooding SHW0579 Mentmore, The Greenway, High Zone 1 Wycombe (6 dwellings) SMA0044 Foxes Piece Marlow Buckinghamshire Zone 1 (10 dw) SMA0096 New Court / Liston Court, Marlow (15 Zone 1 dwellings) SSC0031 Bangalore House, Falcon Court, Zone 1 Wycombe Road, Stokenchurch (25 dwellings) SRD0008 Coal Yard Smalldean Lane Saunderton Zone 1 (10 dwellings) SRD0148 Uplands House Hotel, Four Ashes Zone 1 Road, Cryers Hill (52 dwellings) SWC0064 Orchard House Amersham Road Zone 1 Hazlemere Buckinghamshire HP15 7JH (5 dwellings) SWC0048 Penn School Church Road Penn (75 Zone 1 dwellings) SHW0420 Land to the rear of Quebec Road, High Zone 1 Wycombe (5 dwellings) SSC0023 Land adjacent Longburrow Hall, Potential surface Stokenchurch (10 dwellings) Water flooding issues SHW0326 Swan Frontage (50 dwellings) Zone 2 (fluvial) 90%
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and surface water flooding SHW0334 Land forming part of the former Green Zone 1 Street County First School site, Desborough Street, High Wycombe (27 dwellings) SMA0050 Liston Road Car Park, Marlow (15 dw) Zone 1 SPR0034 Horns Lane Car Park, Princes Zone 1 Risborough (15 dwellings) SHW0463 Corner of Bridge Street /Oxford Road, Zone 1 and part Zone High Wycombe (7 dwellings) 2 (20%) SHW0326 Kingsmead Depot, London Road (50 Zone 2 (70%) and dwellings) potential surface water flooding SHW0017 Rapid House/ Zone 1 Bellfield Road (50 dwellings) SHW0499 RailCo, Boundary Road, Loudwater, Zone 1 High Wycombe (27 dwellings) SHW0561 Notcutts Garden Centre, Clay Lane, Zone 1 High Wycombe (15 dwellings) SLK0004 Land at Thame Road, Longwick (36 Zone 1 dwellings) SLK0006 Land off Barn Road, Longwick (50 Potential Surface dwellings) Water Flooding SLK0007 Land off Bar Lane, Longwick (32 Potential Surface dwellings) Water Flooding SLK0008 Rose Farm, Longwick (21 dwellings) Potential Surface Water Flooding SLK0010 Land off Thame Road to the south of Potential Surface Chestnut Way Junction, Longwick (20 Water Flooding dwellings)
5.10 Appendix 6 of this report includes those sites and parcels of land that are being promoted through the draft Local Plan 2016. Below is a summary of the sites and their characteristics.
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High Wycombe
• Queensway - land near the allotments is identified for a possible cemetery - not for housing. The land is currently Green Belt and could remain as such (ref 1 on Plan).
• Land Off Amersham Road (Tralee Farm). This site is in the Green Belt and could provide a mix of dwellings plus open space. No known Flood Risk. Chiltern District Council is considering further land adjacent to this site for allocation. Again, its Green belt status is a significant constraint. (Ref 2 on Plan).
• Land off Penn Road, Hazlemere. This site is in the Green Belt. No known Flood Risk. Chiltern District Council is considering further land adjacent to this site – its Green belt status is a significant constraint. (Ref 3 on Plan).
• Wycombe Air Park is identified for business use and so not relevant to housing site assessment. Located within Green Belt. (Ref 4 on Plan)
• Land off Horns Lane. This site is within the Green Belt and not subject to any known Flood Risk. It is a small site and its Green Belt status is a significant constraint. (Ref 5 on Plan).
• High Heavens. This is a proposed industrial site and not relevant to the housing site assessment. (Ref 6 on Plan).
• Bassetsbury Lane. This site is noted as being disused allotments and contaminated land. Whilst being available, the contamination issues would indicate that some issue of constraint exists that may restrict development – particularly for a residential end use. (Ref 7 on Plan).
• Land off Glynswood (Green Hill). This site is within the Green Belt and not subject to any known Flood Risk. It is a small site and its Green Belt status is again a significant constraint. (Ref 8 on Plan).
• Leigh Street area – this brownfield land has scope for housing and business development to help regenerate the area. No known Flood Risk. (Ref 9 on Plan)
Princes Risborough
• A large strategic expansion option is identified to the north of the town for around 2,000 to 2,500 homes to contribute to the district’s objectively assessed needs. This site includes
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ponds and drainage channels throughout a field based landscape and so some degree of Flood Risk is likely. The site is not in the Green Belt.
• Culverton Farm Area. This zone has been identified as having potential for residential development growth to south of Princes Risborough. However, the site is a mix of Green belt, Area of Outstanding natural Beauty and is subject to Flood Risk. The land is, therefore, severely constrained.
Woobourn and Bourne End
• Slate Meadow. This site is assessed above. (Ref 1 on Plan)
• Hollands Farm. This is an option for a release of land to the south of Slate Meadow that is currently subject to Green Belt constraint. A small part of the southwest corner may be subject to Flood Risk. (Ref 2 on Plan).
• Land off Northern Heights. This site is subject to Green Belt constraints. In addition there is an acknowledged access constraint. The site would only provide for a small quantum of housing. No known Flood Risk. (Ref 3 on Plan)
Marlow
• Seymour Court Road. This site is extremely small and is subject to significant Green Belt constraints. Not know Flood Risk. (Ref 1 on Plan).
• Oak Tree Road. This site is also subject to Green Belt constraints and affected by AONB designation. Whilst there is no known Flood Risk, the site is heavily constrained. (Ref 2 on Plan)
Rural Areas – Lane End
• Land off Finings Road. This site is also within the AONB and is, therefore, also subject to severe landscape and character designation constraints. (Ref 1 on Plan)
• Land off Simmons Way. This is a brownfield site and not believed to be constrained. (Ref 2 on Plan)
• Land off Ellis Way. This site is within the AONB. (Ref 3 on Plan)
• Land off Marlow Road. This site is within the AONB. (Ref 4 on Plan)
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• land to rear of Sidney House is within the Green Belt and also within AONB. (Ref 5 on Plan)
Rural Areas – Longwick
• Land at Thame Road/Bar Lane. This site is in the countryside but not subject to any known constraints. (Ref 1 on Plan).
• Land at Rose Farm. This site is in the countryside but not subject to any known constraints. (Ref 2 on Plan).
• Land off Thame Road. This site is in the countryside but not subject to any known constraints. (South of Chestnut Way) (Ref 3 on Plan).
Rural Areas – Stokenchurch
• Land off Mill Road could provide opportunities for housing, but lies within the AONB where there are severe landscape/character constraints. (Ref 1 on plan).
• Land adjoining Stokenchurch Business Park. An option to extend the business park and so not relevant to the housing assessment. (Ref 2 on plan).
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6.0 SEQUENTIAL TEST
6.1 As noted above, the housing development needs of the District are 15,100 new dwellings during the period 2013 to 2033. The recently published draft Local Plan notes that some 10,000 new dwellings are to be accommodated within the High Wycombe area. At present the remaining need of 5,000 new dwellings is to be provided in the adjoining Aylesbury Vale District, although with the body of response from the communities in Aylesbury Vale objecting to this strategy there are serious questions over the ability of the Council to deliver housing in the adjoining district. It is envisaged that a proportion of High Wycombe District’s objectively assessed housing need will ‘come back’ to the district placing further pressure on the need to urgently release land for housing.
6.2 Importantly, the emerging Local Plan 2016 elevates the Slate Meadow site from a safeguarded site, which has historically been removed from the Green Belt in successive iterations of local plans, to provide the facility to meet future growth needs, to a draft housing allocation. The need for Slate Meadow, and the other identified reserve sites to be release for housing, in fulfillment of their long-standing role has arrived.
6.3 In appraising all the sites identified in the tables above, together with those emerging through the draft Local Plan 2016, it is clear that the Council will need to find housing sites that are beyond Flood Zone 1 (some in Flood Zone 2). The Council has already identified sites and assessed these as being necessary:
• Swan Frontage 90% within Flood Zone 2 (50 dwelling units); • Baker Street car park 90% within Flood Zone 2 (96 dwelling units); • Kingsmead Depot, London Road 70% within Flood Zone 2 (50 dwelling units); • Slate Meadow 70% Flood Zone 1, 30% Flood Zone 2 and a small pocket of flood zone 3a (150 - 190 dwelling units); and • Land at Culverton Farm and to the rear of Poppy Road.
Slate Meadow compares favourably with the Swan Frontage, Baker Street and Kings Mead Depot sites insofar as the land has significantly less area affected by Flood Zone 2. It is also important to clarify that the previous thirty percent figure for Slate Meadow (above) is based on the old flood mapping. Taking into account the newer and approved flood modeling this figure is too high and is actually misleading, as development is not envisaged on the vast majority of the flood zone 2 land. Thus the ‘correct’ percentage for the Slate Meadow site is significantly lower and the site is markedly better than it appears above and within the Council’s papers.
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6.4 In view of this High Wycombe is unable to meet all its objectively assessed needs within its own District on Flood Zone 1 land and it needs Flood Zone 2 land. There is no evidence that alternative Flood Zone 1 sites are either deliverable or viable and consistent with sustainability principles that could be identified as an alternative to Slate Meadow. The summary review of the accompanying sustainability appraisal presented in Section 2.0 of this report confirms that Slate Meadow scores very highly on all key indicators of sustainability – a key Government driver for the delivery of new homes.
6.5 In addition to this and, at a more specific level, it is important to bear in mind that the majority of the site to be developed is in Flood Zone 1 which is the sequentially preferred location for new housing. Approximately 25% of the overall site lies within Flood Zone 2. Of this area a small proportion (a few percent at the most) will be raised above the 100-year plus climate change and the 1,000-year flood levels to return it to flood zone 1 classification. Whilst a very small part of the site is in Flood Zone 3a it is not intended to build in there – none of the land falls within Flood Zone 3b. In real and practical terms, therefore, the new homes on the site will be provided on flood zone 1 land with the residual designed, engineered and managed to protect future and existing residents from flooding.
6.6 In view of this and taking the wider benefits into account it is considered that the site meets the terms of the sequential test.
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Exceptions Test
6.7 A small, triangulated parcel of land in the south western corner of Slate Meadow lies within flood zone 3a - figure 6 refers. This parcel of land lies beyond the flood zone 1 area of the site that will form the development platform for the new homes. The area will remain undeveloped and will not, therefore, have a material effect on the delivery of the site. In view of this it is debatable whether the exceptions test is needed.
6.8 However, a precautionary approach has been adopted and the principles of the exception test have been followed with the provision of:
• Evidence that there will be wider sustainability benefits to the community – this is demonstrated through the accompanying sustainability appraisal referenced briefly in Section 2.0 of this report; and
• A site-specific flood risk assessment that clearly demonstrates that the development will be safe for its lifetime taking account of the vulnerability of its users. The assessment also demonstrates that flood risk will not be increased elsewhere – particularly in the Cores End area, and that flood risk is mitigated and reduced overall.
6.9 The parcel of land identified in figure 6 (coloured orange) is particularly small amounting to approximately two percent of the overall land area of Slate Meadow. It is, therefore, arguably de minimus in flood risk and planning terms. However, it is acknowledged that in the normal course of events that the presence of Flood Zone 3a land requires the Exceptions Test to be undertaken. HR Wallingford has undertaken a full/detailed flood modeling exercise of the site and its surroundings. The scope, methodology and modeling parameters were agreed by the Environment Agency on 7th September 2016, following formal consultation, collaborative working and refinement. The preparation of the site-specific flood risk assessment and mitigation will be carefully developed to ensure that the baseline complies with the 1 in 100 year (plus thirty-five percent) parameter and, indeed, the 1 in 1,000 year event. All housing will be provided on flood zone 1.
6.10 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 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.
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6.11 In this particular case both criteria are complied with. The proposal demonstrates that it is highly sustainable – details are presented within a combination of section 2.0 and the plans within Appendix 1, together with the site wide development brief prepared by the District Council and Croudace and Avant Hones. The site is exceptionally well located and integrated with the existing built up area and facilities and services. It is not in a location, which might affect landscape character and provides the facility to provide centrally located and accessible affordable homes, together with contributions. The site is opposite St Paul’s Church of England Primary School, significant employment areas lies within walking distance, along with a wealth of retail and community uses, which are readily accessible on foot or via established bus links which are nearby.
6.12 The development proposals are designed in such a way that there is no flood impact as a result of the development. Whilst a small undeveloped part of the site is defined as Flood Zone 3a, the practical implications of this designation together with the mitigation proposed and agreed with the Environment Agency, ensures that the significant benefits of providing up to 170 new homes in a demonstrably sustainable location clearly outweigh the negligible flood risk. A Flood Risk Assessment will be prepared to clearly demonstrate that the development will be safe. The finished floor levels of properties will be set well above the local flood levels with a freeboard to accommodate a 100 year event plus climate change effects. In practice a high level of protection will be afforded with flood risk being mitigated and reduced overall, together with improvements in the Cores End area.
6.13 The Slate Meadow site is necessary now given the fact that High Wycombe cannot demonstrate a 5-year housing land supply and required to contribute towards the delivery of a minimum requirement of 10,000 homes within High Wycombe District. With the uncertainties surrounding the re-apportionment of 5,000 houses to Ayelsbury Vale District this figure may well increase.
6.14 In this particular case the evidence is clear that:
• The site is needed to help meet the objectively assessed housing needs of the District and that there are no sequentially preferable alternative sites that are comparable in size and are available within either Flood Zone 1 or Flood Zone 2 given the level of housing need. • The site proposals will be accompanied by a Flood Risk Assessment that demonstrates that the development proposals will not increase flood risk to others and that the surface water drainage and flood risk from the nearby river are able to be managed. • The site is in a sustainable location and attached at Appendix 1 are extracts of the sustainability appraisal prepared for the site, clearly demonstrating that the site meets the
43 Kember Loudon Williams September 2016 Slate Meadow, Bourne End Sequential Test – D9 presumption in favour of sustainable development (paragraph 14 of NPPF) and its release for housing accords with paragraph 49 of NPPF.
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7.0 CONCLUSION
7.1 This sequential assessment has been prepared to accompany a planning application and to assist Wycombe District Council in the collaborative preparation of a development brief to realize housing on Slate Meadow in fulfillment of the long standing removal of the site from the Green Belt to support the sustainable delivery of new homes. It is anticipated that the appraisal will support the Council’s assessment of a full planning application for the development of the land up to 170 new homes.
7.2 The site is located mainly located within Flood Zone 1, with Flood Zone 2 making up a small proportion and Flood Zone 3a being restricted to a small pocket of land close to the river. The proposed built development described as a ‘more vulnerable’ use is confined to Flood Zone 1 and a small area currently defined as Flood Zone 2 but which will be re-engineered to, in practical terms, lift it out of this particular zone and into Flood Zone 1.
7.3 If the Council accept that the ‘more vulnerable’ residential use is all contained within Flood Zone 1 then the proposals have met the sequential test and are in an appropriate location. If, by virtue of the development being partially on a small area of Flood Zone 2, it is concluded that the sequential test needs to consider other, alternative sites that lie within Flood Zone 1, then the review of sites clearly demonstrates that the Slate Meadow site is necessary in order to meet a severe current shortage in housing land supply and to meet a future planned delivery of some 15,100 new homes.
7.4 The sites that have been reviewed through the Council’s Housing and Economic Land Availability Assessment, in November of last year (incorporating February 2014 SHLAA sites) all come with opportunities and constraints, but fundamentally each must be achievable, sustainable and deliverable to meet the tests of NPPF. Given the Council’s continued failure to meet its five-year land supply position and the need now to provide circa 15,000 houses up to 2033, the urgent delivery of sites is key. In the Council’s evidence base for the Core Strategy and in all its other documents and reports the Slate Meadow site is identified as being necessary to help meet that housing need.
7.5 The review of all sites that are reasonably available demonstrates that if the delivery of new homes was limited solely to land falling within flood risk zone 1, the Council will continue to be faced with a significant housing land supply shortfall of several thousand new homes. This need is such that some of the Council’s objectively assessed need is being promoted within Aylesbury Vale District, although for the reasons stated this strategy may, by necessity, need to change.
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7.6 The Council is also endorsing the formal allocation of all of the reserve sites including Slate Meadow. Until this plan is adopted the Council is in severe shortfall in terms of housing land. No reasonable alternatives have been identified that outperform Slate Meadow in flood risk or sustainability terms: which are not encumbered by policies of restraint such as Green Belt and Area of Outstanding Natural Beauty designations. Consequently Slate Meadow is necessary to contribute towards the Council’s shortfall in housing supply. The sustainability appraisal presented in summary within this report demonstrates the locational, social, economic and environmental advantages of the site that support its release for housing.
7.7 The history of under delivery within the District, together with the identified constraints, market conditions and viability issues, all support the urgent delivery of Slate Meadow, which has historically been identified for development. With the formal engagement of the principal controlling interests, Croudace and Avant Homes, with the Council through the Planning Performance Agreement process and the collaborative preparation of a site-wide masterplan and development brief, Slate Meadow is available and deliverable now. The site will provide a meaningful contribution to the District’s housing needs in a sustainable location, whilst reducing the pressure to release less sustainable parcels of land, often within the Green Belt or the Chilterns AONB, on the edges of settlements.
7.8 If it is concluded that the Exceptions Test ought to apply because of the small pocket of Flood Zone 3a land then the assessment confirms that the risk through flooding would be negligible. A site-specific flood risk assessment will be prepared to demonstrate that there will be no adverse impact on occupiers of the development and that the new homes will be safe for their lifetime. The Slate Meadow development would meet wider sustainability benefits, which clearly outweigh the minimal risk given the Flood Zone designations affecting this site (Flood Zone 3a is a tiny portion of the while site and will not be built upon).
7.9 The review of alternative sites demonstrates that Slate Meadow, through the collaborative workings of HR Wallingford and the Environment Agency, can accommodate up to 170 homes in flood zone 1, where there is a low probability of flooding. This can be achieved without increasing the risk of flooding to others. The homes can be provided in part fulfillment of the Council’s housing need and with the benefit of the sustainable advantages of the site, can be provided in accordance with the presumption in favour of sustainable development.
7.10 In summary then:
• Slate Meadow has been removed from the Green Belt and identified as a reserved site for development in successive iterations of Local Plan and Core Strategy policy documents;
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• The Council has not met its five-year housing land supply target and, added to the objectively assessed need requirement for the district of some 15,100 new homes to 2033 the site, along with the other reserve sites is required urgently to provide new homes; • The vast majority of the site that will be developed lies within Flood Zone 1 – the sequentially preferable location for the provision of new homes; • Whilst a small proportion of the site (approximately 25% of the overall site area) is in Flood Zone 2 it is only intended to develop in a very small part of this. The small part of Zone 2 to be included in the development will be raised well above the 100 year plus climate change and the 1,000 year flood levels; • Although a very small part of the site is in Flood Zone 3a (approximately two percent) it is not intended to build in this area; • None of the site is in Flood Zone 3b (the functional flood plain, flooding on a 1 in 20 year event); • Whilst a Sequential Test is required, the whole approach is to develop in the higher land – the Sequential Approach promoted with the Sequential Test; • Whilst the need for an exception test is questionable as none of the actual housing is in Zone 3a, evidence demonstrates that the release of the site for new homes would convey sustainability advantages for the community; and • A flood risk assessment will be prepared to demonstrate that the development will be safe over its lifetime and that flood risk will not be increased elsewhere as a result of the development.
7.11 In view of this and in the absence of any viable alternative sites, therefore, it is incumbent upon the Council to take a balanced and pragmatic approach in accordance with the Government’s stated aims established within the NPPF.
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Appendix 1
Sustainability Appraisal Plans
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Highways & Movement
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Landscape Designations and Features
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Community & Social Facilities
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Retail and Employment, Slate Meadow
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Appendix 2
Environment Agency Review and Acceptance of Flood Model
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11 KEY FINDINGS AND RECOMMENDED ACTIONS Findings: Original Action Final Comment RED: Action required AMBER: Action recommended GREEN: Satisfactory Overall, a good, well-constructed model with adequate Required changes have been schematisation of the various processes required in the study reach. made. Some minor omissions of structures do not detract from the results for the proposed housing area. However, uncertainty in bank levels could be the difference between the site flooding or not. Survey has not been provided with Provide survey to verify Survey has been provided. the review to verify decisions parameters/dimensions Structure dimensions and types regarding structure dimensions, match those expected. coefficients and roughness. Panel markers and roughness changes Justify panel marker Reason for error has been appear to be applied in illogical selection or amend adequately justified and places in the middle of the channel described as appropriately amended with little difference to results. CONFIRMED BY MODEL Weir W3A requires a void polygon to Add void polygon Polygon stated as added. Little prevent the ingress of flooding difference observed to results. CONFIRMED BY MODEL Both weirs in the model require Add bypassing spills Spills stated as added. Little bypassing spills difference observed to results. CONFIRMED BY MODEL Reporting is missing statements of Add statements on model Section added to report. model parameters, uncertainties and parameters, uncertainties However, it is worth noting that assumptions. and assumptions to report. whilst the cumulative effect of changes to modelled levels arising from this review are small, changes to flood extents are larger. As model extents are sensitive to small changes in level, a conservative approach to the consideration of flood risk would be required. Hydrologically, a slightly higher flow than previous studies has been used. The 0.1% AEP event begins flooding Lower initial flow for this This has been stated as amended. at the first time step event to prevent flooding CONFIRMED BY MODEL. at first time step The source of flooding to the study Sensitivity test bank A review of modelled animation area is very sensitive to the reliability elevations in this area. Re- results shows that this low point of its input data as the width of bank survey bank to verify is the sole source of flooding to overtopping is only 9 m. correct level. the site up to the 100 year (although expanded to 25m in
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width for higher RPs) and for the 1000 year event provides the majority of flood flow to the site (~0.6 m3/s peak flow relative to an ingress point to the east with a flow of ~0.02 m3/s). It is entirely possible that additional animal trampling of this point, or small errors in surveyed levels of the effective bank crest (<0.1m) may result in bank levels being lower (or possibly higher) and therefore a large change in flood extent given that: a) It is stated in the report that large changes in extent are observed despite small changes in level. b) Roughness sensitivity of 20% generates changes in water level from 0.03 to 0.08m (which is also plausible change in bank level due to error or trampling) c) Flow sensitivity through climate change varies levels up to 0.05m
It is not considered that further modelling is required. The justification for the elevations in this area, and the additional evidence supplied are sufficient. However, from review of the model, results and report, it can be concluded that flood extents, and the onset of flooding, are highly variable depending on roughness, flow and bank levels. Flood depths are less susceptible. For the proposed site, it would be expected that this variability is taken into account when considering the finished floor levels, containing exceedance flows and number or properties at risk.
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Appendix 3
Extracts from National Planning Policy Guidance – Definitions
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Table1 – Flood Zones
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Table 2 – Flood Risk Vulnerability Classification
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Table 3 – Flood Risk Vulnerability and Flood Zone ‘Compatibility.’
Appendix 2
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Appendix 4 Extracts from Site Delivery and Allocations Supporting Document 2012
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Appendix 5 Extracts from Site Delivery and Allocations Supporting Document 2012
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Appendix 6
Draft Local Plan 2016 – proposed housing sites
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• Queensway - land near the allotments could provide a new cemetery whilst staying in the green belt (1) • Land Off Amersham Road (Tralee Farm) releasing this large site from the green belt could provide homes and green areas. Chiltern District Council is considering further land adjacent to this site. (2) • Land off Penn Road, Hazlemere – considering the option to take this land out of the green belt for new homes. Chiltern District Council is considering further land adjacent to this site. (3) • Wycombe Air Park could be used to attract new businesses and create new jobs. It would mean intensifying how the existing site is used and identifying some undeveloped land and the airfield will remain in use. This would involve making some changes to the green belt boundaries to allow controlled expansion whilst the remainder of the airfield remains in the green belt. (4) • Land off Horns Lane—taking this land out of the green belt could provide a limited number of homes. (5) • High Heavens – land next to the household waste-recycling centre could be used for low value industry. This would involve changing the green belt boundary including around the waste-recycling centre. (6) • Bassetsbury Lane –these disused allotments (which are contaminated) could provide starter and affordable homes. (7) • Land off Glynswood (Green Hill) – releasing this site from the green belt could provide a limited amount of homes. (8) • Leigh Street area – this brownfield land has scope for housing and business development to help regenerate the area. (9)
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Allocates an expansion area to the town for around 2,000 to 2,500 homes to contribute to the districts objectively assessed needs.
Option for further growth to south of Princes Risborough
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• Slate Meadow - is a reserve which we have already decided to release for development. We are working with the local liaison group to set out a detailed development brief which potential developers will have to adhere to. (1) • Hollands Farm - releasing this large site from the green belt could provide homes and green areas. This might provide the opportunity for a new link road between Cores End Road and Ferry Lane delivering an alternative to some traffic going through Bourne End. (2) • Land off Northern Heights - releasing this site from the green belt might provide a limited number of homes but only if a satisfactory access to the site can be secured. (3)
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• Seymour Court Road – release of a very small site from the green belt for a few homes. (1) • Oak Tree Road – considering the option of taking land out of the Green Belt for housing at the northern end of the road. (2)
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Rural Areas
• Land off Finings Road (1) • Land off Simmons Way (2) • Land off Ellis Way (3)
• Land off Marlow Road (4) • land to rear of Sidney House is proposed to be taken out of the green belt. (5)
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• Land at Thame Road/Bar Lane (1) • Land at Rose Farm (2) • Land off Thame Road (south of Chestnut Way) (3)
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• Land off Mill Road could provide a large site for homes. (1) • Land adjoining Stokenchurch Business Park –extending the business park could provide more jobs. (2)
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