Consultation Draft
Urban Capacity Study
 

 

 

 

 

 


June 2002

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



Urban Capacity Study

 

1.  Introduction

 

1.1              As part of the Unitary Development Plan (UDP) review, the Isle of Wight Council has undertaken an urban capacity study to assess the potential of the settlements on the Island to accommodate new development.  It was agreed that an immediate review of the UDP be undertaken after it was adopted to fully take into account the implication of the new PPG3 and in particular the issue of phasing of development sites using the sequential approach as indicated in PPG3.  This report is the first stage of a review of the UDP.

 

1.2              Recent Government Guidance in revised PPG3 highlighted the Government’s commitment to promote more sustainable patterns of development, by maximising the re-use of previously developed land.  The reasoning behind such an approach is twofold.  Firstly it will promote urban regeneration; and secondly it will reduce the amount of greenfield land being taken for development.  The national target for the re-use of previously developed land is that by 2008, 60% of additional housing should be provided on previously developed land and through conversion of existing buildings.

 

1.3              The aim of the study is to provide a realistic estimate of the level of additional development that could potentially be accommodated within the existing urban areas on the Island.  For the purposes of the study, urban areas have been defined as “areas within the development envelope of Towns and villages”.  The information within the report will be used to inform the process for the review of the Unitary Development Plan, and will help in providing a baseline for a sequential approach to the allocation of housing sites, and the managed release of sites.

 

1.4              This document outlines the methodology used by the Council.  It will form a background paper to the review of the UDP, which was adopted on 18th May 2001.  It is not subject to formal representations as part of the development plan process, but the Council do intend to consult with regard to the methodology and assumptions used.  

 

1.5              This study has been undertaken in line with the Government guidance outlined in the DETR document “Tapping the Potential” (December 2000) It is therefore considered that the methodology used meets the principles and advice outlined in the DETR guidance.

 

1.6              It is anticipated that this study will continue to be monitored on a regular basis.

 

1.7              Because of the issue of confidentiality, this paper is not site specific, but provides a broad indication of the level of development that could be achieved on the Island.

 

Should you have any queries with regard to this document, please contact:

 

Wendy Perera

Planning Policy, Corporate & Environment Services,

Seaclose Offices, Fairlee Road, Newport, IW.

Tel: (01983) 823596

Email: [email protected]


 

2. Study Method

 

2.1              The study has focussed wholly upon the identification of previously developed land that could potentially be suitable for new development.  However, it should be recognised that some sites identified may be more appropriately utilised for uses other than housing, such as retail, or employment.

 

2.2              The study has been undertaken in a series of stages, which can be broadly described as follows:

 

1.      Identifying capacity resources

2.      Surveying the capacity

3.      Assessing yield

4.      Discount the potential to provide an assessment of the capacity that can be realised.

 

The remainder of this document deals with more detailed information with regard to the four stages listed above.

 

Identifying the area to be Assessed

 

2.3       The development envelope boundaries for urban areas (regardless of size) have recently been confirmed through the UDP process.  At the UDP Inquiry the Inspector heard a number of in depth arguments with regard to development envelope issues, and his report contained very few suggestions for changing either the Council’s approach to the use of development envelope boundaries to define the built extent of settlements; or site/settlement specific issues.  The Unitary Development Plan was adopted on 18th May 2001, and the study uses as its baseline the Development Envelope Boundaries as defined within Policy G1 of the adopted UDP.

 

2.4              There may be other settlements, which do not have defined development envelopes, but contain previously developed sites.  These settlements are however deemed to be “countryside”, and not generally appropriate for new development (other than specific exceptions) and therefore they have not been included within this study.   Policy H9 of the UDP deals with such exception sites, which are by definition, sites only to be released where exceptional needs become evident, and they could be previously developed or greenfield sites.  This approach is in line with government guidance which states that rural exception sites are in addition to identified capacity and that they relate to land that would not normally be released for housing. In any case, the capacity in such areas would be minimal.

 

2.5              Initial fieldwork included a full survey of all towns/villages with development envelopes, involving a comprehensive survey of all areas.  The survey identified sources of capacity as outlines in the table over the page.

 


Identification of Capacity Sources

 

2.6       The table below outlines the sources of capacity that were identified and are included within the urban capacity study.

 

Source

Description

Large sites – those previously developed sites that are over 1 ha in size.

Sites within existing defined development envelopes, which can be considered to be brownfield sites, as defined in Annex A of PPG3 have been identified.  This included sites within single or multiple ownership, all previously developed vacant land, vacant land not previously developed and sites not otherwise allocated. Sites with the benefit of planning permission at December 2001 have been excluded from the survey.

Small sites – sites under 1 ha in size.

(see description above)..  Small sites make up a large proportion of the housing land availability stock on the Island.  An assessment based upon past trends is considered to be the appropriate way of assessing the potential from such sites.  Examples of such sites would be: flats over shops; infill plots; conversion of commercial buildings and existing housing.

Vacant dwellings/empty properties

The annual average number of properties brought back into use via Housing Section funds.

Car Parks and Employment Land

All car parks, allocated employment land, and existing employment land within defined development envelopes was totalled.  Assumptions will be made as to the proportion that is likely to come forward.  Allocated employment land OUTSIDE of development envelopes has not been included

Conversions

Conversion of non-residential buildings.

 

2.7       The results of the initial fieldwork have been plotted onto a GIS and the data collated with regard to site size.

 

Assessment of Potential Yield.

 

2.8              This section assesses the potential for housing development within defined development envelopes for each of the listed sources in turn.  The results have been achieved through a combination of site surveys and desk studies (as already discussed).  The results provide a unconstrained capacity figure, which is the theoretical total number of dwellings that could be accommodated if all the potential capacity was developed optimally.  Each capacity source outlined in the table above is discussed in more detail, and as assessed potential calculated.

 

Discounting the potential

 

2.9              It is however unrealistic to assume that the theoretical number of dwellings will be developed and the unconstrained figure needs to be adjusted based on the prediction of how much capacity can be brought forward by 2011.  This is addressed through a “discounting” procedure, taking into account what is likely to be realistically achieved within the context established by PPG3.

 

2.10          In reaching appropriate discounting rates, “Tapping the Potential” draws attention to the need to take into account the developability of sites, including the willingness of owners to release the site for development, as well as physical constraints, market viability and character of the area.  It provides ranges for each of the capacity sources and emphasises that the appropriate discount rate should be established by planning authorities, based on professional judgements, and knowledge of the area.  For each of the capacity sources, an appropriate discount rate has therefore been applied and is explained in the discussion of each source.

 

Large Capacity Sites (over 1 ha)

 

2.11     A total of 19 sites have been identified, amounting to some 27.39 hectares of land.  Current trends show that large housing sites are being developed at densities of 29 dph.  This however includes all sites, both green and brownfield.  Brownfield sites alone are currently being developed at densities of 28 dph.    This figure is based on all sites currently included within the housing land availability database.  In comparison, the 2000/2001 Local Best Value Performance Indicator shows that the average density of large housing sites was 26dph.  Assumptions have therefore been based upon a minimum density of 30 dph and maximum density of 30dph (net).  

 

2.12     An assessment has been made on the housing potential for each site, having taken into account any obvious constraints on development.  The approach taken was consistent with the guidance in “Tapping the Potential”, in that a density multiplier was applied to each site. The density multiplier used was dependant upon the site size:  1-2 ha 75-90%; .2 ha 50-75%; and under 1 ha 100%. On larger sites there may be a need to take account of the provision of distributor roads, schools, open space serving a wider area and landscape strips, all of which reduce the developable area of a site.   

 

2.13     This methodology has the benefit of being a practical way of dealing with sites and makes assessment more manageable because figures may be produced quickly and are consistent. The assessed capacity of this source amounts to between 600-700 units at a net density of 30dph and between 650-800 units at a net density of 35 dph.

 

2.14     Not all large sites identified as suitable for housing are likely to be released and will be affected by factors such as willingness of owners to release land, infrastructure capacity, market viability and site amalgamation.  They could also be affected by policy decisions such as compulsory purchase or revised parking standards.

 

2.15     For this reason, it has been assumed that such sites will be released in line with past trends.  Large windfall sites are currently yielding an average of 27 dwellings per annum (based on data from the last 4 years).  These sites have been single ownership sites that have been “easy” to develop.  Only a small proportion of the urban capacity sites identified are single ownership, and it is felt that this will have an impact on the likelihood of the sites coming forward.   Using this trend of approximately 30  units, per annum, and taking into consideration the multiple ownership issue, and assuming that the trend will continue, approximately 40% of assessed capacity is likely to come forward. 

 

2.16     Using past trends the assessed capacity of this source amounts to between 250 to 320 units.


 

Small Capacity Sites (under 1 ha)

 

A total of 1000 sites were identified, covering some 143 hectares.   The average site size was 0.13 ha.  The study assumes that the majority of these sites will yield only 1 dwelling.  Small sites make up the largest proportion of capacity on the Island, as can be illustrated by the graph opposite. 

 

2.17          In particular, this could have implications for the provision of affordable housing units, which can only currently be negotiated on sites meeting threshold criteria. 

 

2.18     Projected small site figures based upon the last five years data suggest that an average of 140 dwellings per annum could come forward.  Whilst this figure is higher than that identified from the capacity survey, it is considered inappropriate to use this trend, because the supply of small sites will be declining over the years.

 

2.19     This gives a potential assessed capacity  of 1000 units. 

 

Vacant/Empty Properties

 

2.20     The scope for bringing a significant number of vacant dwellings back into use is considered to be limited.  The vacancy rate on the Island is comparable with the national rate.  For this reason the Housing Section target figures have been used to make assumptions about the number of dwellings likely to come back into use.  The target figure for re-use of empty properties is 26 dwellings per annum, however, the Housing Section is actually achieving approximately 30 dwellings per annum.  It is assumed that this rate will continue for the foreseeable future.

 

2.21     The assessed potential of this source amounts to 300 dwellings.

 

Conversions

 

2.22     These are usually small sites, providing between 1 and 9 units per site.  Conversions of non-residential properties and conversions of residential properties are currently providing an average of 75 units per annum.  This study assumes that this rate will continue. 

 

2.23     The assessed potential of this source amounts to  750 units.

 

Other Potential Sources

 

2.24     These sources include existing employment uses, allocated employment sites and existing car park sites.  Open spaces and other green sites within development envelopes have been excluded from this study.  The amount of employment land identified totalled 33.38 ha, and a further 13.44 ha of land currently used for car parking was also identified.

 

2.25     Car parks in particular are a sensitive subject, with PPG13 seeking less car parking and “Tapping the potential” advising that even well used car parks can yield capacity.  On the other hand, local businesses and town centre users often call for more car parking. 

 

2.26     Existing employment uses and employment allocations  probably offer the only real opportunity for large brownfield sites to come forward.  However, the UDP includes employment policies that seek to retain existing employment uses and promote the employment allocations.  Whilst mixed uses is also promoted on some sites, it is difficult to estimate the potential from such sources, therefore it has been assumed that a minimum of 7% of the total area of car parks and employment uses will become available for residential development, at an average net density of 30 dph.

 

2.27     The assessed potential of this source  amounts to 160 units.

 

2.28     The table below illustrates the total assessed yield from capacity sources.

 

Capacity Source

Assessed Yield

Large Sites

250-320

Small Sites

1000

Empty Properties

300

Conversions

750

Car Parks/Employment Sites

160

Total

2460-2530

3.      Overview of Supply of Housing Land

 

3.1       Current completion rates are over the minimum provision required by RPG9.  This means that completion rates could fall below 520 per annum, but the total requirement from RPG9 could still be met.  The chart below illustrates the completion data since 1991

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


3.2              The elements of urban capacity discussed above are all subject to potential variations.  The overall picture of supply of housing land also involves the housing allocations and extant approvals, which combine to make up the residential land availability database (not including greenfield sites).  Assumptions have been made that 70% of residential land availability will be developed during the plan period.  This allows for the fact that some allocations, which were based upon existing commitments may not be considered appropriate for renewal if the developments are not completed under existing approvals.

 

 

3.3              The overall picture is shown in the table below:

 

Capacity Source

Yield (2001/2011)

Residential Land availability

2800

Large urban capacity sites

250-320

Small urban capacity sites

1000

Empty properties

300

Conversions

750

Car parks/employment sites

160

Provision

5260-5330

RPG9 requirement to 2011

5200

 

3.4              The Council recognises that the potential identified on previously developed land through the urban capacity study may not be as great as some parties would wish, conversely it will be seen as an overestimate by others.  The Council believes it is a realistic assessment.

4.      Implications of the Urban Capacity Study for the UDP

 

4.1       The Urban capacity study cannot be seen in isolation.  The results of the Urban Capacity Study will inevitably have implications in a number of areas, including the Council’s development resources, bids to other agencies, land assembly requirements, decontamination and parking and density standards and more importantly the potential revision of housing allocations.  As already discussed in the introduction, the review of land allocations is the main reason for undertaking this study.

 

4.2                          The UDP will need to manage provision within an overall threshold and the end result of this study will be the identification policy decisions needed and the implications of achieving a particular target for housing provision.

 

4.3       PPG3 provides guidance on a sequential approach to housing development, and the need to phase sites.  The urban capacity study has illustrated that there is not enough brownfield land likely to become available to meet our housing need in the long-term.

5.      Conclusion

 

5.1              Using the realistic capacity potential, the greenfield allocations contained within the UDP will still be required, but decisions remain to be made as to when these sites should come on-line.  Consideration of phasing the release of allocated greenfield sites will form the second stage of the review of the UDP.


Appendix A

 

Breakdown of Potential Capacity sites by Area

 

Area

Type

Ha

Cowes

Large sites

0.00

Small sites

14.17

East Cowes

Large sites

0.00

Small sites

8.92

Newport

Large sites

14.13

Small sites

26.34

North East Wight

Large sites

2.61

Small sites

42.58

South East Wight

Large sites

2.67

Small sites

20.86

West Wight

Large sites

4.35

Small sites

9.28

Rural towns & Villages

Large sites

5.06

Small sites

21.62