Strategic Environmental Assessment (SEA) for the Shenley Park SPD

6. Reasonable alternatives assessment

Introduction

6.1 The aim of this section is to present assessment findings in relation to the concept masterplan reasonable alternatives introduced above.

N.B. the assessment is as per that presented in the Non-technical Summary.

Assessment findings

6.2 Table 6.1 presents the assessment.

6.3 With regards to assessment methodology:

Within each row (i.e. for each of the SEA framework topics) the columns to the right hand firstly rank the alternatives in order of preference and then, secondly, highlight instances of a predicted significant positive effects (green), moderate or uncertain positive effects (light green), moderate or uncertain negative effects (amber) and significant negative effects (red) significant effect on the baseline (mindful of established objectives). Also, '=' is used where it is not possible to confidently differentiate between the alternatives.

Table 6.1: Reasonable alternatives assessment findings

Topic	Option 1 Emerging preferred option	Option 2 Archaeology in situ	Option 3 Avoid the south	Option 4 Whaddon buffer
	Rank (number) and significant effects (shading)
Biodiversity	2	3		3
Climate change		2	2	2
Communities		2	2
Historic env	=	=	=	=
Landscape	2	3		3
Land and water	=	=	=	=
Transport		2	2	2

Discussion

The assessment shows a mixed picture, with each option associated with a degree of relative merit. Option 1 performs well in a number of respects; however, it is important to be clear that it is not for SEA to arrive at an overall conclusion on which of the options is 'best'. That is because SEA is undertaken without any assumptions made in respect of the degree of importance, or 'weight', that should be assigned to each of the topics that make up the SEA framework. It is for the plan-maker to assign weight and then decide which option is preferred on balance.

Having made these initial points, the following bullets consider each topic in turn:

• Biodiversity – the key consideration here is Whaddon Chase, which is a collection of woodlands associated with a former royal hunting forest. Key components of Whaddon Chase surround the southern part of the site. Also, within the southern part of the site is the Tattenhoe Brook corridor along with several linked areas of woodland that likely contribute to ecological functioning within the Whaddon Chase landscape (a Biodiversity Opportunity Area).
  
  On the face of things, the Whaddon Chase constraint / opportunity might serve to indicate a preference for Option 3, which would avoid development in the sensitive southern part of the site. However, under this scenario there would still need to be a road corridor through the southern parcel, and the landowner might well still continue to promote the southern parcel for development, as opposed to making the land available for green infrastructure in perpetuity.
  
  With regards to Options 2 and 4, there is limited biodiversity argument for a new area of parkland over the archaeological site (Option 2) or larger landscape gap to Whaddon (Option 4) at the expense of increased housing delivery in the southwest of the site, including in proximity to Whaddon Chase woodlands.
  
  In conclusion, it is fair to highlight Option 3 as having a degree of merit in theory; however, in practice, and with a long-term perspective, this is less clear. Option 1 also performs well given that this approach to broad layout within the site has formed the basis for recent work to consider link road options (see Figure A above, also discussion below) as part of a wider effort to ensure that the SPD is suitably 'future-proofed', including mindful of long-term strategic planning for Whaddon Chase, including the possibility of woodland creation (see Appendix 9 of the DLA Evidence Study, also Section 9 of the main report).
   
• Climate change – beginning with the matter of climate change adaptation / resilience, flood risk is typically a primary consideration, and this is the case for Shenley Park, where a small brook passes through the southern half of the site. There might be a theoretical argument in support of Option 3, with a view to extensively buffering the river corridor; however, in practice, and with a long-term perspective, it is not clear that this is the case, for the reasons discussed above, under 'Biodiversity. The assumption under all of the alternatives is that the brook would be integrated within an extended Tattenhoe Valley Park.
  
  Moving onto climate change mitigation / decarbonisation, the primary consideration is minimising per capita greenhouse gas emissions from transport, which primarily means minimising the need to travel and supporting a modal shift away from the private car towards public and active transport.
  
  In this respect, key considerations are: A) all options can deliver a new public transport route through H7 (with a link to the local centre); B) Option 2 would not align well with a desire to make best use of Shenley Road as an active travel route, nor weight growth in proximity to the MK-edge (particularly the nearby Westcroft District Centre); and C) Option 1 has formed the basis for detailed work to consider link road options (as discussed above), including work around future-proofing for a possible Mass Rapid Transit system for MK and/or a Park and Ride to the SW of the City (potentially west of the Bottledump roundabout).
  
  Finally, with regards to the objective of minimising per capita greenhouse gas emissions from the built environment, the scale of Shenley Park gives rise to a theoretical opportunity, as does the potential to support fairly high-density development and a mix of uses in the northern half of the site (i.e. housing alongside a community centre). Specifically, there could be an opportunity in respect of achieving a standard of regulated operational emissions that exceeds the requirements of Building Regulations, and feasibly even achievement of net zero emissions (ideally without offsetting, i.e. 'onsite net zero'). Also, there might be an opportunity in respect of non-operational emissions, which are unregulated, e.g. embodied carbon in building materials.
  
  In this light, a consideration is whether any of the alternatives would necessitate a higher density local centre / higher density scheme in the northern half of the site; however, it is not clear that this is a significant consideration.
  
  Another consideration is development viability, with a need to ensure that funding is available for decarbonisation / net zero focused measures. There is a viability argument for supporting growth across the site (Option 1), including within the southern area where new homes would need to be lower density (reflecting the sensitivities) and hence would have strong viability credentials. Furthermore, in the absence of support for new homes in the southern part of the site there could well continue to be pressure for growth here in the future, leading to a risk of 'piecemeal' growth with opportunities missed for securing developer contributions and investment in zero carbon focused measures.
  
  In conclusion, Option 1 is supported from a perspective of both transport and built environment decarbonisation and does not give rise to any significant concerns from an adaptation perspective. Under Option 1 the effect of the SPD would certainly be to secure an improvement on the baseline, but it is not clear that this benefit would be 'significant' in the context of a climate emergency.
   
• Communities, health and wellbeing – focusing on Option 4, this would see a much larger landscape gap to Whaddon, which is a historic and by all accounts thriving village community. However, there is a clear argument for a buffer that is 'the right size' in terms of both ensuring separation and enabling good integration between the communities either side. In this light, there is thought to be a widespread understanding that, whilst the Whaddon buffer must be of a good size, what is of equal or similar importance is that it is of a high quality, including via investment in landscaping and measures to support active use.
  
  Also, under Option 4 the effect would also be that a major emphasis of open space delivery within the site would be at the northwest extent, with a very strong concentration in this one area, potentially at the expense of open space elsewhere within the site (in terms of land availability and potentially also investment), including locations accessible from the existing MK edge. In this respect Option 2 potentially has a degree of merit, as there would be a new strategic open space adjacent to the current MK edge. However, in practice, it is not clear that there is a particular need for this (albeit it could be high quality including with measures around archaeological interpretation). The primary green infrastructure opportunity is around the Tatternhoe Valley Park extension.
  
  Finally, under Option 4, there is a need to consider possible issues around road and public transport connectivity, including from a future-proofing perspective, and mindful of the importance of avoiding problematic levels of traffic through Shenley Park (with resulting 'communities' impacts).
  
  In conclusion, it is fair to highlight theoretical support for Option 4, mindful of the views of Whaddon Parish Council around ensuring a good-sized landscape buffer. However, it is important to recognise potential drawbacks / challenges.
   
• Historic environment – as discussed, the archaeological constraint affecting the central eastern part of the site (a Roman settlement, associated with the Shenley Road, which was a minor Roman road) was a key focus of discussion and technical work over the period 2022 to 2023. This culminated in a CHIA (2023) recommending that it is not necessary to preserve the site in situ, as it is of only local significance. Also, there is a need to consider the benefits of excavation (in terms of research etc), and also an understanding that the remains could be at risk of damage under a baseline scenario involving continued agricultural use of the land. In this light, it would not be appropriate to conclude a preference for Option 2, mindful of knock on implications for planning within the other land parcels within Shenley Park as well as, feasibly, implications for futureproofing, terms of strategic planning for the Whaddon area, Bottlehouse Farm (locally significant) and the Whaddon Chase landscape.
  
  In conclusion, it is not possible to differentiate between the alternatives with any certainty. With regards to significant effects, neutral effects are predicted; however, there is an argument for predicting positive effects on the baseline, which is a 'no SPD' scenario. There is an urgent need for the SPD to be in place so that it can inform and guide the forthcoming planning application.
   
• Landscape – there is a clear theoretical argument in support of Option 3. However, in practice, and with a long-term perspective, this theoretical argument can be questioned, as has been discussed. It is crucially important that the SPD supports comprehensive and future-proofed growth, as opposed to risking piecemeal growth, which might even be described as 'sprawl'. It is hard to imagine the southern part of Shenley Park being left undeveloped in the long term and, in this light, there is a need to ensure a strategic approach is taken to sympathetic development, potentially to include strategic infrastructure, within what is a sensitive landscape including Tattenhoe Brook and Whaddon Chase.
  
  Under Option 1 there would be the potential for lower density and high-quality housing growth in the southern part of the site. For example, the DLA Report (2023) discusses "opportunities for development running along, not across, the contours, using the south facing slopes and the linear park as key design influences, resulting in more varied and bespoke design responses..."
  
  In conclusion, it is fair to highlight theoretical support for Option 3; however, in practice, there is an argument to suggest that Option 1 could be preferable. With regards to significant effects, there is a need to recall that there are no nationally designated landscapes in the area, albeit there is a case for 'larger-than-local' significance in the context of committed and possible further strategic growth elsewhere to the south / southwest of MK.
   
• Land and water – the majority of the site has been surveyed in detail and found to comprise land that is not of 'best and most versatile' (BMV) quality, as defined by the NPPF. Specifically, the land is of Grade 3b quality, whilst the NPPF defines BMV as land that is of Grade 1, 2 or 3a quality. In this light, there is limited argument for leaving the southern part of the site undeveloped and in continued use of agriculture, given that the effect could be to increase pressure for growth at locations elsewhere associated with higher quality land. There are some parts of the MK-edge known to be associated with Grade 2 quality land.
  
  With regards to water, the only matter for consideration (recalling the scope of the SPD) is water quality within the brook that bisects the southern part of the site. However, there is no reason to suggest a particular concern, or any particular opportunity, under any of the reasonable alternatives. It is fair to assume high quality Sustainable Drainage Systems (SuDS) under all scenarios.
  
  In conclusion, the alternatives perform on a par with neutral effects predicted.
   
• Transport – this is a key issue, and one that has already been explored above. Detailed work has been undertaken to explore options for road connectivity (see Figure A), with this work assuming a broad approach in line with Option 1. This preferred approach involves an inner 'street', but also land reserved for a new strategic link / grid road. A final decision on the most appropriate approach will need to be made in light of future transport modelling. Also, there may be a need to account for proposals in the early stages of development for a Mass Rapid Transit system for MK and/or the potential for a Park and Ride to the SW of the City (which may be sited to the west of the Bottledump roundabout).
  
  It is difficult to conclude with certainty that options other than Option 1 would conflict with strategic transport objectives, including from a future-proofing perspective. However, issues could arise, for example under: Option 4, including due to pressure for housing growth at the southwest extent of the site; and Option 3, where there would be a need for a new road link – strategic or otherwise – through the southern parcel without housing growth alongside.
  
  Aside from the configuration of road / public transport links within the site and the wider area, the other key consideration is active travel links to key destinations including Westcroft District Centre, Salden Chase (where there is an approved reserve site for a new secondary school) and Central MK. Matters have already been discussed above, under the 'Climate change' heading.
  
  In conclusion, Option 1 preferred and differential effects are judged to be of some significance, albeit there is uncertainty ahead of further work. There is a need to recall the baseline ('no SPD') situation, which could involve pressure for higher growth within the site without suitably strategic infrastructure planning.