Joint Core Strategy - Proposed Main Modifications

11 Conclusions

The influence of the SA Addendum on the JCS

11.1 This SA Addendum Report brings together the results of an intense period of work over seven months that has sought to identify the effects of a range of alternatives to the JCS as submitted in order to ensure that the final adopted JCS will be the most sustainable one for West Northamptonshire.

11.2 The SA Addendum work builds on the earlier SA work on the JCS as submitted. It is not intended to replace the earlier SA work, but to supplement it, by providing further more detailed assessment as necessary in order to help the JPU make decisions and choose the most appropriate strategy for development over the period covered by the plan.

11.3 The SA Addendum work has involved close working between LUC, as the appointed SA consultants, and the JPU, with the findings of the SA work feeding into the decision-making process throughout.  The SA Addendum work takes into account an extension to the end date of the JCS plan period from 2026 to 2029.  It has also taken into account up-to-date evidence on the objectively assessed housing and jobs provided by independent consultants, plus other technical studies as relevant.

11.4 The aim of the SA Addendum work has been to be as objective and consistent as possible.  It used the same SA objectives that were developed for the earlier SA work up until submission of the JCS.  However, the work on the SA Addendum has been undertaken in much more detail than the earlier SA work drawing on up-to-date evidence base, using Geographical Information Systems (GIS) techniques for analysis of data, and using a new and comprehensive set of assumptions to underpin judgements of effects.

11.5 Although the SA has considered the sustainability effects of all the Proposed Main Modifications, the primary focus of the work has been on the alternative options for the SUEs that are needed at the four main towns of Northampton, Daventry, Towcester and Brackley and the options for new settlements and strategic employment sites.

11.6 To ensure that all reasonable alternatives were subject to SA on a consistent basis, a full and thorough assessment of the potential of all the undeveloped areas adjoining each of the four towns to act as SUEs was undertaken.   The only exceptions were those areas that were considered not to be reasonable alternatives under policy guidance contained in the NPPF, or because they did not meet the objectives and strategy of the JCS as submitted.  In practice, this meant that there was almost complete coverage of the areas surrounding all four towns.

11.7 In turn, this meant that those areas already allocated as SUEs in the JCS as submitted were re-assessed, plus alternative areas put forward by other stakeholders, and sites identified through the SHLAA process.

11.8 It was from this comprehensive and detailed work, and the additional technical work gathered by the JPU, that the Preferred Choice that is presented in the Proposed Main Modifications was prepared by the JPU for consideration by the West Northamptonshire Joint Strategic Planning Committee.  Compared to the JCS as submitted, it results in changes primarily at Northampton, with three SUEs considered capable of accepting more development (Northampton North, Northampton West, and Northampton South of Brackmills), plus a new SUE at Northampton Upton Lodge/Norwood Farm, which is a committed site but is now allocated as an SUE with increased development proposed.  The SUEs at Daventry, Towcester and Brackley remained largely unchanged.

11.9 The JPU considered all other options would have either unacceptable impacts or would be undeliverable over the plan period for a variety of reasons, taking into account all the SA and other technical work it had at its disposal.

11.10 The SA work involved carrying out an assessment on an equivalent basis of the alternative approach to SUEs at Northampton put forward by Northamptonshire County Council.  This alternative would have meant deleting two SUEs (Northampton South and Northampton West), and expanding Northampton North SUE by the equivalent amount of housing (2,500 dwellings).  The assessment found that although the areas of greenfield land to the west and south of Northampton would remain undeveloped and the potential positive and negative effects of the Northampton West, Northampton South SUEs would therefore not occur, the significant effects identified for Northampton North would extend over a greater area.

11.11 In addition to the SUEs, the SA also assessed reasonable alternative strategic employment sites, including the new M1 Junction 16 site that is included in the Proposed Main Modifications, and two potential new settlement alternatives.  With respect to the Junction 16 strategic employment site, potentially significant negative effects were identified with respect to landscape and air quality and noise, although its potential for negative effects on biodiversity were considered to be less than any of the other alternatives considered.  With respect to the new settlement alternatives, it was found that the two specific site options considered, as well as the broad approach of allocating new settlements, had generally less positive sustainability effects than the preferred approach in the JCS of focusing development within and adjoining the urban areas.

11.12 The objectively assessed housing and jobs needs work has indicated that a very significant amount of development is required in the JCS area.  Delivery of this development will have significant positive social and economic effects.  The SA Addendum work has confirmed that there are no alternatives for delivering the scale of development needed in the JCS area without some significant negative effects occurring.  Given that it is impossible, and probably undesirable in sustainability terms, to concentrate even more development within the urban areas than is presented in the Proposed Main Modifications, it is inevitable that greenfield land will need to be developed.  This in turn will mean that there will be some significant negative effects on the landscape, biodiversity and cultural heritage, both for some individual SUEs but also cumulatively across the JCS area as a whole.  Mitigation can be provided through high quality design, the provision of green infrastructure including habitat creation, encouragement of sustainable modes of transport, and the development of balanced neighbourhoods integrated with existing development.  But effects will still occur, wherever the development takes place. 

11.13 The SA Addendum has identified the effects of developing in different locations in the JCS area, primarily around the four main settlements, and the JPU in turn has sought to avoid where possible the most sensitive environmental locations, while also having to be guided by other factors (e.g. transport implications).  For example, the JPU has deliberately avoided choosing locations for SUEs that could affect the integrity of the internationally important Upper Nene Valley Gravel Pits nature conservation site.  This does not mean that all potentially sensitive locations have been avoided, but it is reasonable to conclude that the alternatives would also result in significant effects, although they would be experienced in different locations.

Cumulative effects

11.14 The earlier SA work on the JCS as submitted identified a number of potential cumulative effects.  In addition to the cumulative effects identified in the earlier SA work, there is the potential for cumulative effects arising from the proposed strategic employment site at Junction 16 on air quality and noise associated with traffic using the M1.  There is also the potential for cumulative effects of increasing the amount of development to be delivered through ‘urban capacity’ sites (likely to be a large number of smaller sites) on the townscape of Northampton and flood risk of both existing and new development.  The overall increase in development in the Proposed Main Modifications will inevitably put pressure on natural resources, and in this respect there could be cumulative significant negative effects on the achievement of Water Framework Directive objectives and targets.

Difficulties encountered

11.15 The main difficulty encountered while carrying out the SA work was determining the appropriate method for assessing all the areas of land that, at least in theory, had the potential to become SUEs, and then ensuring that each was appraised on a consistent and objective basis.

11.16 It is for this reason that detailed assumption tables were drawn up in order to make the process for making judgements as transparent and systematic as possible.  This resulted in a large number of appraisal matrices being produced but it was felt this needed to be done if the SA work, and the decisions linked to the work, was to prove robust and reliable.


11.17 Once the JCS is adopted, the significant effects identified in the earlier SA work and this SA Addendum will need to be monitored.  In addition to the monitoring framework contained in the earlier SA work, it is considered that the JPU will need to work with partners to monitor the following significant effects:

  • Effects on noise and air quality associated with Northampton South SUE, development within the Northampton urban area, and Junction 16 strategic and DIRFT employment sites.
  • Effects on cultural heritage associated with the SUEs at Northampton South of Brackmills, Northampton North of Whitehills, Northampton Upton Park, Northampton Upton Lodge/Norwood Farm, Daventry North East, and from development within the urban area at Northampton.
  • Effects on biodiversity, flora and fauna at virtually all the SUEs, and the DIRFT strategic employment site.
  • Effects on access to educational facilities for virtually all the SUEs and from development within the urban area of Northampton.
  • Effects on health including access to health facilities at virtually all the SUEs and from development within the urban area of Northampton.
  • Effects on employment land take-up and job creation of SUEs at Northampton North, Northampton Kings Heath SUE, Brackley East, Towcester South East, development within the urban area of Northampton, and at the two strategic employment sites.
  • Effects on the landscape from development at virtually all the SUEs, the Junction 16 strategic employment site, and the significant positive effects identified from development in the urban area of Northampton.
  • Effects on objectively assessed housing needs and community facilities and service provision at all the SUEs, and from development in the urban area of Northampton.
  • Effects on loss of best and most versatile agricultural land at Northampton North SUE, and Daventry North East SUE, and effects on land stability at Daventry North East SUE.
  • Effects on flood risk from development within the urban area of Northampton.

11.18 It is recommended that a comprehensive combined monitoring framework is provided in the SA Adoption Statement to accompany the JCS when adopted.



December 2013