Strategic Housing Land Availability Assessment (SHLAA) Draft Methodology

Ended on the 22nd October 2012
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3. The Methodology

3.1. The Council will be following the methodology approach as set out in the Government Guidance published by the DCLG in July 2007.

3.2. The guidance sets out an eight stage assessment process, with two additional optional stages:

  1. Planning the Assessment
  2. Determining which sources of sites will be included in the Assessment.
  3. Desk top review of existing information.
  4. Determining which sites and areas will be surveyed.
  5. Carrying out the survey
  6. Estimating the housing potential of each site.
  7. Assessing when and whether sites are likely to be developed.
    1. Assessing suitability for housing
    2. Assessing availability for housing
    3. Assessing achievability for housing.
    4. Overcoming Constraints.
  8. Review of Assessment

Optional Stages

  1. Identifying and assessing the housing potential of broad locations – This stage may be required.
  2. Determining the housing potential of windfall – whilst windfall has made a significant contribution in the past, it is not expected to have such an impact in the future.

Stage 1: Planning the Assessment

3.3. The guidance recommends that the assessment should be carried out in partnership with local planning authorities in the housing market area. Harlow is in partnership with five other Districts in the M11/LCB East housing market area, although each is at a different stage in preparing their respective SHLAAs.

3.4. Consequently it is considered that joint assessment would be impracticable. However, these Districts will be invited to be part of the partners/stakeholders group.

3.5. Key Stakeholders will be invited to participate in an assessment group. These will include: (details in Appendix 1)

  • Adjoining Districts (Epping Forest District Council, East Hertfordshire DC)
  • Remainder of Market area partnership (Uttlesford, Brentwood and Broxbourne)
  • Registered Social Landlords
  • Developers or their agents with a vested interest in Harlow
  • Local Property Agents
  • Local groups e.g. Civic Society

3.6. The project will be resourced from within the Council’s Planning and Housing teams where there is local knowledge of local policy and detailed knowledge of the town and specific sites and locations.

3.7. Managerial responsibility will remain within Planning Services and will be held by the Forward Planning Manager.

(1) Stage 2: Determining which sources of sites will be included in the Assessment.

3.8. The DCLG Guidance sets out two categories of sources of potential housing sites; those in the planning process; and those not in the planning process.

Sites in the Planning Process
Site Source Data Source
Land Allocated (or with permission for non housing uses) no longer required for that use Council Development Management Database; Adopted Local Plan.
Existing Housing Allocations and site development Briefs Adopted Local Plan; Extant Development Briefs
Unimplemented/outstanding planning permissions for housing Council’s Housing Development Monitoring Database
Planning Permissions for houses under construction Council’s Housing Development Monitoring Database
Sites not currently in planning process
Site Source Data Source
Development Industry identified land Call for Sites
Private Individual identified Site Call for Sites
Essex County Council identified Sites Call for Sites
Harlow Council ownership identified Site Call for Sites (in house request)
Sites Previously Considered Past records now plotted on GIS
Urban Capacity Study 2006 Urban Capacity Study 2006
Other Candidate Sites (sites not identified elsewhere) Including School sites and Allotments Open Spaces Study, desk top study (GIS)
Vacant/Derelict land and buildings National Land Use Database (NLUD)
Opportunity Sites Representations to Adopted Local Plan inquiry;

3.9. Harlow is a former New Town and has been planned from its inception. This means that many sites have a functional use, for example school playing fields, local public open space, arising from the Master Plan for the town prepared by Sir Fredrick Gibberd.

3.10. In preparing this study it is clear that some sources of land will be in areas identified in the Adopted Replacement Harlow Local Plan as Green Belt (national policy) or Green Wedge (local policy) or Internal Open Spaces (local policy). Government guidance makes it clear that for the purposes of this exercise the scope of land assessed should not be excluded because of existing planning policies designed to constrain development.

3.11. Much of Harlow’s allocated employment land is concentrated in two designated and self-contained employment areas. Residential development on sites within these areas would, in most instances, relate poorly to their surroundings notwithstanding the potential environmental conflicts that would occur. However, this does not preclude any of these sites coming forward, or being put forward for consideration.

Stage 3: Desktop review of existing information

3.12. Sources identified in Stage 2: have been mapped along with associated site data.

3.13. The Council carried out a ‘Call for Sites’ in late 2009. This involved sending letters out to interested parties (Developers, land owners, agents etc.), adverts in the local press and articles in the local press. This attracted a number of candidate sites, which were plotted on Geographical Information System (GIS).

3.14. The ‘Call for Sites’ remains open for new submissions.

3.15. A key factor in the assessment is determining which sites should be included in the study. The bulk of the town’s housing supply has been dependant on a few strategic sites set out in the Adopted Replacement Harlow Local Plan such as Church Langley, Newhall, and the Gateway Scheme. Indeed Newhall continues to be developed.

3.16. Harlow was planned to ensure the provision of a considerable amount of open land between neighbourhoods and within neighbourhoods. These have been plotted and will be assessed alongside other sites.

3.17. The planned nature of Harlow arising from its New Town heritage has meant that unlike more traditional towns there has been little scope for contributions to the housing land supply from windfall development. Windfall sites have not been specifically identified as available in the Local Plan process. They normally comprise previously-developed sites that have unexpectedly become available. Indeed the Housing Trajectory for 2010-2011 indicates that around 15 dwellings per annum would be completed from extant planning permissions consisting of sites of less than 10 dwellings.

3.18. Historically as part of the Land Availability studies development sites of less than 11 dwellings were considered a small site, and were amalgamated as part of the overall assessment. However, a number of these sites make a valuable contribution to the land supply and should not be considered windfall sites.

3.19. To recognise the contribution that small sites make in Harlow the minimum size threshold of 6 dwellings or 0.2hectares (equivalent to 30 dwellings per hectare) will be included within the assessment. Site sizes smaller than this will be outside the scope of the assessment.

Stage 4: Determining which sites and areas will be surveyed.

3.20. The study will be confined to land within the District boundary. Adjoining authorities are at different stages in the preparation of their plans. Harlow Council together with both Epping Forest DC and East Hertfordshire DC have cooperated on a number of planning issues and evidence studies, and it is clear having regard to the provisions in the Localism Act 2011 this cooperation will continue, indeed both Districts have identified Harlow Council as a key stakeholder.

3.21. The compact size of Harlow and its planned nature means that many of the sites known to the local planning authority, and consequently may not need additional site surveys. Sites from previous land studies have been incorporated into the assessment.

3.22. Sites with planning permission are monitored with site visits as part of an ongoing programme to inform development progress for housing trajectories for the AMR.

3.23. Outcomes from the “Open Space Study” have already helped identify additional candidate sites for further assessment. This study is a comprehensive review of open land in the town. The outcome of this study will give further information to assess sites suitability for development.

Stage 5: Carrying out the survey

3.24. Site surveys and desktop assessments will be carried out by Planning Officers following consistent practice in identifying sites and recording information.

3.25. Comprehensive information supplied as part of the call for sites (public and private) may mean that detailed site surveys will not be required. However, if it is clear that it is not possible to assess the site from given or known information then an officer will visit the site.

3.26. The “Open Space Study” identifies additional candidate sites which will warrant a site visit particularly if its characteristics are unfamiliar to the surveying officer.

3.27. Characteristics recorded are where possible:

  • Site Size
  • Boundary
  • Current Use
  • Preferred Use
  • Surrounding land use
  • Character of surrounding area
  • Access to services/highway
  • Physical constraints
  • Current policy impacts
  • Development progress
  • Initial assessment of housing potential

3.28. Generally this information was recorded at the ‘Call for Sites’ phase, and is contained in a database linked to GIS overlays. Further sites have been identified as part of a going process, and plotted on a GIS system.

Stage 6: Estimating the housing potential of each site

3.29. Government guidance suggests that estimation of the housing potential of each site should be guided by the existing or emerging plan policies, at the local level.

3.30. The Adopted Replacement Harlow Local Plan (ARHLP) indicates that new residential development should be built at 30 dwellings per hectare or more (policy H1). Preamble to the policy suggests that in town centre locations this may be higher and that hese densities should be compatible with the character of the area and any urban design policies and guidance.

3.31. The Local Plan also allows for higher densities than existing on previously developed land (Policy BE3).

3.32. The Council has an adopted Design Guide Supplementary Planning Document (SPD). Whilst it is not specific in housing density it is clear that one of the adopted design principles is new development should be ‘compact’ to ensure that land is used efficiently, and density of development is one measure of compactness. The SPD point out that developing compact neighbourhoods is one of Gibberd’s founding principles for the New Town. The Design Guide Principle is as follows:

Principle DG3: Compact Development

Neighbourhoods should continue to be developed in a compact, well-defined pattern, supported by an identifiable and accessible centre.

New development should maintain the pattern of separate, distinct neighbourhoods; building on Harlow’s existing character and avoiding the creation of continuous extensions to existing neighbourhoods (urban sprawl).

3.33. The Design Guide includes a further Principle which states:

Principle DG27: Housing Groups

Large scale new development will be expected to create ‘housing groups’, each with a distinct character. A cohesive character should be achieved through the careful use of building materials and architectural styles.

Housing groups should contain a mix of tenures. They should form compact and easily identifiable places. They should not be so large as to result in bland or monotonous urban sprawl. Excessive or tokenistic variety which would create an incoherent character should be avoided.

Mixed tenure developments are encouraged.

Buildings must be designed in the context of surrounding built development and in conjunction with the spaces between them.

3.34. Neither of these principles sets out specific density requirements for new housing development.

3.35. A study commissioned by the Council reviews the Master Planning Principles of the town as set down by Sir Fredrick Gibberd originally1. This study was to provide a technical baseline of understanding that will assist with guiding any further regeneration and growth in the Harlow Area. It is considered that this particular study provides an excellent basis for estimating housing potential, and allows for comparison with existing areas in Harlow.

3.36. The study includes a set of overarching sustainability objectives which indicate densities which reflect the ‘Gibberd Principles’ for the growth and regeneration of the town.

3.37. These are as follows:

  • Maintain Harlow’s tradition of high density neighbourhoods. Achieve minimum densities of 40dph, in line with Gibberd Plan;
  • Achieve higher densities (up to 50 dph) in locations closer to Neighbourhood and Town Centres.
  • Redevelop ‘hatches’ as new higher density mixed use sites incorporating retail.
  • Consider allowing part redevelopment of hatches for new higher density housing.
  • Introduce new higher density building forms along edges of strategic open space/openspaces
  • Density should decrease as you move away from the most highly serviced locations.
  • Based on walkable catchment areas.

3.38. It should be noted that the NPPF, does not prescribe densities, however the guidance states that local planning authorities set out their own approach to housing density to reflect local circumstances.

3.39. For the purposes of the SHLAA an overall view needs to be taken of the contribution that these sites may make, and an objective scheme of assessing the potential yield needs to be provided.

3.40. Design and layout for individual assessed sites is probably the best way to establish the yield of new housing. Some of the sites which will be assessed have already provided tentative layouts and/or proposed dwelling yield, and where this is the case those figures will be used. However, for those sites where numbers of dwellings have not been indicated, the following table will be applied for the assessment to arrive at a notional capacity.

Site Characteristic

Density (Dwellings Per Hectare) Net


6 dwellings or less 30 average Policy H1 RHLP
Within new neighbourhoods 40 average To reflect Harlow’s average
Adjacent to transport nodes or neighbourhood centres or Hatches 50 average As recommended in “Harlow Study Area Masterplanning Principles & Sustainability Criteria”
Matrix Partnership with Halcrow & Levett-Therivel
Location is within Town centre Neighbourhood centre or Hatches 50 -100

3.41. The yield from each of the identified sites is based on the net developable area not the gross. On those sites where a net area has not been indicated the table below will set the ratio. For the smaller sites it is generally accepted that existing services, roads, and open space will serve the new development.

3.42. To calculate the net developable area in line with common practice the following table sets out the gross to net ratios.

Site Size Gross to Net
Ratio Standard
Up to 0.4 hectare 100%
0.4 to 2 hectares 90%
2 hectares and above 75%

Stage 7: Assessing when and whether sites are likely to be developed.

3.43. By assessing a site’s suitability, availability, and achievability will enable a judgement to be made in the plan making context as to whether a site can be considered deliverable, developable, or not currently developable. These are defined as follows::

  • Deliverable – a site is available now, offers a suitable location for housing development now and there is reasonable prospect that housing will be delivered on site within 5 years from the date of adoption of the plan, and
  • Developable - a site should be in a suitable location for housing development, and there should be a reasonable prospect that it will be available for and could be developed at a specific point in time.
  • Not currently developable – not deemed to meet above two criteria.

3.44. Stage 7 of the guidance is split into 4 parts to assess the suitability, availability, and achievability of a site.

Stage 7a: Assessing suitability for housing.

3.45. A site is considered suitable for housing if it offers a suitable location and would contribute to the creation of sustainable, mixed communities. Sites allocated in existing plans will generally be suitable; however it may be necessary to revisit them to ascertain if the circumstances have changed which will have a bearing on the sites suitability and/or availability.

3.46. To ensure consistency of the study a site appraisal form has been devised (Appendix 3) to assess the suitability of sites.

3.47. As already stated the adjoining districts SHLAAs are at a different stage to Harlow. However, whilst this SHLAA will be looking at sites within the Harlow boundary, some sites straddle the boundary, and consequently these will be appraised if appropriate.

3.48. The Matrix study reviewing the Master Planning Principles of the town as set down by Sir Fredrick Gibberd1 has been referenced to help establish the criteria to appraise the sites. The study is a high level document which sets out a broad principles and criteria for new development. The study suggests some principles which are relevant for this stage of the assessment. These have been identified as follows:

  • Maintains a link to open countryside that respects the green wedge principle.
  • Respects/enhances original local landscape character
  • Respects/enhances original masterplan principles
  • Minimise need to travel
  • Potential to minimise car reliance
  • Use of Brownfield land a priority
  • Minimise greenfield landtake
  • Avoid spread of development outside of 5-10 minute catchment of local amenities
  • Utilisation of undeveloped walkable catchment locations for new high density mixed use development
  • Achieve minimum densities of 40dph
  • Achieve higher up to 50dph closer to neighbourhoods and town centre.
  • Redevelops local hatches
  • Restructures Neighbourhood Centres
  • Utilisation of ‘non-functional’ open space

3.49. Where possible these principles have been incorporated into the criteria which will be used to assess suitability (Detailed Criteria are in Appendix 2). These are:

Major Affect on Suitability – Nationally recognised designations, which may affect suitability.

  • Impact on flood risk
    • Flood zones 2 and 3
  • Impact on biodiversity assets
    • RAMSAR
    • National Nature Reserve (NNR)
    • Special Areas of Conservation (SAC)
    • Sites of Special Scientific Interest (SSSI)
    • Ancient Woodland
    • Tree Preservation Order (TPO)
  • Impact on historic, cultural and built environment
    • Scheduled Ancient Monument
    • Historic Park/Garden
    • Listed Building
  • National Policy
    • Green Belt

Local Affect on Suitability – Local Policy designations that may affect suitability.

  • Impact on biodiversity assets
    • Local Nature Reserves (LNR)
    • Wildlife Sites
    • Wildlife Verges
  • Noise impact
    • Potential impact from existing noise sources
  • Air Quality
    • Potential impact on the site
    • Sites Potential impact on the area
  • Contaminated Land
    • May affect viability of any development potential.
  • Development affecting a conservation area.
    • Impact on character or appearance
    • Proposed use is compatible within a conservation area.
  • Known or suspected archaeological remains.
    • May affect viability of any development potential.
  • Green Wedge principle
    • Site is in a Green Wedge.
  • Respects or enhances original landscape character
    • Minimises greenfield landtake
    • Utilises ‘non-functional’ open space (based on Open Space Study)
  • Utilises Previously Developed Land
    • Redevelops a local shopping hatch
    • Restructures a neighbourhood centre
    • On Previously Developed Land
  • Regeneration
    • Contribution site could make to regeneration of the area

Access to Community and Social Infrastructure

  • Access to Sustainable Transport Modes
    • Distance to train station
    • Distance to bus stop
    • Accessibility to cycle network
  • Access to Schools
    • Travel mode and distance to primary school
    • Travel mode to secondary school
  • Access to health facilities
    • Accessible by public transport to GP surgery
    • Accessible by public transport to Hospital
  • Access to retail centres
    • Walking distance to shopping hatch
    • Access by public transport to neighbourhood centre and town centre.
  • Access to Employment Areas
    • Accessible by public transport to major employment areas at Pinnacles/Templefields
  • Access to provision for children and young people
    • Local Area for Play (LAP)
    • Locally Equipped Areas for Play (LEAP)
    • Neighbourhood Equipped Areas for Play (NEAP)

Other Factors – additional issues which may affect the sites suitability for development

  • Access
    • Is there direct access to the site
    • Does access need upgrading to current highway standards
    • Does the access serve existing development
  • Site specific impacts
    • Does the site relate well to adjacent land or development
    • Does the topography affect the suitability
    • Does the site’s shape affect development potential
    • Does development of this site land lock adjacent potential sites
    • Is the site affected by adjacent land uses
    • Does the site’s planning history have a bearing on the suitability

3.50. A copy of the appraisal form is contained in Appendix 3. It uses a “traffic light method of assessment (red: amber: green), which provides a visual reference to help understand the issues/constraints the proposed site may have. The number of ‘red’ or ‘green’ does not necessarily rule in or out a particular site but indicates how likely its development may be. For example issues/constraints on a ‘red’ indicated site may be mitigated, or it falls foul of a policy designation cannot automatically be rejected (as recommended by Government guidance)

3.51. In addition a scoring system has been assigned to compare in absolute terms one site with another. Red would score 1; Amber 2; and Green 3. Whilst this does allow some comparison to assist in sites suitability, it must be weighed against the other factors of availability and achievability.

Stage 7b: Assessing availability for housing.

3.52. The call for sites exercise and other identification of potential sites was carried out in early 2010. It is possible that the status of some of these sites has changed in that period. It is proposed that developers and their agents and other respondents are contacted to appraise them of the latest progress, but specifically to ascertain if:

  1. Is the site still available for housing?
  2. If not how have circumstances changed

3.53. If there is no response from the contact, the Council will endeavour to ascertain the new owner/agent. If this is not forthcoming it will be assumed that there is doubt over the availability of the site, and will be considered not currently developable.

3.54. In addition other tests to assess availability will be as follows:

  • Legal Issues
    • Is there a ransom strip to be overcome
    • Multi ownerships
    • Is there a restrictive covenant on the site
  • Ownership
    • Not in the ownership of the sites’ sponsor
    • Ownership not known
    • Owner intention (see paragraph 3.52)
  • Current use
    • Is there an established use on the site
    • Is it a non conforming use

Stage 7c: Assessing achievability for housing.

3.55. A site is considered achievable for development where there is reasonable prospect of that the housing will be developed on the site at a particular point in time. This is a question of economic viability of the site, and the capacity of the developer to build and sell the housing over a certain period. This will be affected by, market factors at the time (viability of existing use, land value of alternative uses, location, demand, projected sale); cost factors (site preparation costs, planning obligations, funding prospects); and delivery factors (phasing, build rates, single or several developers, capacity of the developer).

3.56. The call for sites exercise identified a number of sites that may have significant infrastructure costs associated with them. If possible these will be identified in the site appraisal along with other potential costs such as contributions to Essex County Council for education, and the requirement to provide 33% affordable housing on sites providing 15 or more dwellings. On sites where there is doubt that development is achievable, the Council will consult the Assessment Group (appendix 1), to ascertain if this conclusion is supported.

Work of the Assessment Group

3.57. Group members will be drawn from the sectors identified in paragraph 3.5 above. It is anticipated that the consultation within the group can be carried out using electronic means. However, it may be necessary to hold group meetings if required.

3.58. Group members will be provided with information for each site which will include:

  • Location plan
  • Site plan
  • Aerial Photo if available
  • Details of potential uses
  • An assessment as to whether the site is: achievable; and suitable. Sites will only be assessed if they are available (see paragraph 3.49).

3.59. Group members will review the information and the Planning Officers’ assessment. Group members can then append their assessment. The consensus view can then be used to determine if the site is deliverable and developable.

Stage 7d: Overcoming Constraints

3.60. If the assessment identifies any constraints, then it should include what actions would be needed to remove them. Actions to remove them may include:

  • Investment in new infrastructure
  • Dealing with fragmented land ownership
  • Environmental improvement
  • Assessment of relevance of the Planning Policy constraining development.

Stage 8: Review of the Assessment

3.61. Once the assessment of the deliverability/developability has been completed, an assessment of whether there are sufficient or surplus sites to meet the Council’s housing requirement will need to be made. The housing potential can then be incorporated into the Council’s housing trajectory.

3.62. The test for sufficiency depends on the assessment being carried out as part of a plan review to identify sites required for the first 10 years of a plan, and preferably for 15 years of the plan, or whether the assessment is being reviewed to help the 5 year land supply.

3.63. If there are sufficient sites to meet these requirements then the most sustainable and deliverable sites (depending on policy reviews) will be supported but if there is insufficient housing arising from the sites identified then it is necessary to investigate how this shortfall can be planned for. See stages 9 and 10.

Stage 9: Identifying and assessing the potential of broad locations

3.64. If sufficient specific sites cannot be identified to meet Harlow’s housing requirement then guidance suggests that broad locations for growth can be considered. The guidance states this is a proactive approach to planning.

3.65. The guidance suggests examples of broad locations, which in Harlow’s case is likely be outside the District boundary. If that is the case the emerging Development Plan Strategy will identify broad locations for growth, working with other public bodies, if there is insufficient capacity within Harlow’s boundaries to meet Harlow’s housing requirement.

Stage 10: Determine the housing potential of windfall (where justified)

3.66. Government advice states that the supply of land for housing should be based upon specific sites, and possibly broad locations. However, guidance recognises that in some authorities there are local circumstances where a windfall allowance is justified.

3.67. Whilst each year the Council approves a number of sites which have not been identified as available as part of the local plan process, the number has not been consistant or predictable. Sources of past windfall have come from a wide range, for example developing the garden of an existing house to the conversion of a major town centre office block.

3.68. Harlow’s new town master planning means that there is little scope for windfall development to make a major contribution to housing supply. Monitoring of housing completions has not indicated any pattern in windfall that could be reliably used to predict future supply.

3.69. Consequently it is considered that an allowance for windfall as part of the housing land supply is not justified.

1 Harlow Study Area Masterplanning Principles and Sustainability Criteria. Matrix Partnership with Halcrow and Levett-Therivel
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