The Constraints & Opportunities for Deenethorpe Airfield Development
The Joint Core Strategy Policy 14 establishes criteria, which will need to be met in order for a proposal to be supported. This section presents the preliminary environmental, social and economic assessment work and conclusions, to inform the plan preparation process and initial Master planning; and sets the scene for the emerging design and master plan ideas which accord with Policy 14 (Section 3).
a) Landscape Character and Visual Amenity
A detailed landscape and visual appraisal has been undertaken and confirms that the site does not fall within a statutory or local landscape designation.
The site is located on a plateau with a valley associated with the Willow Brook to the west of the site. The ridgeline runs to the west of the retained main runway on the site with the land falling away gently towards Upper Benefield. The new garden village will be sited to ensure that it does not break the ridgeline.
The landscape assessment concludes that the proposed development would not result in significant levels of adverse visual effects. A series of viewpoints have been taken around the site (following consultation with the local authority) and these have identified that any impact is both limited and localised in nature. Long distance views of the site are restricted both by the topography and existing vegetation cover. The assessment concludes that the proposed garden village can be accommodated into the rural environment without having direct impacts on the adjoining villages of Deenethorpe and Upper Benefield. The appraisal recommends that the access from the A43 will need to be carefully designed by following suitable contours within a landscaped corridor.
The landscape/visual impact appraisal has been used to inform a preliminary master plan and the landscape strategy for the site. It includes extensive new woodland planting to complement the existing structure and create greater connectivity with the wider Rockingham Forest landscape and setting.
The preliminary conclusions are;
(i) The setting of existing villages can be comprehensively protected and enhanced. There will be no clear views from existing settlements as a consequence of retained existing vegetation and views will be screened and filtered by extensive areas of new woodland;
(ii) The scale and nature of new green infrastructure will be very beneficial and structural planting will create robust green edges and landscape enhancement;
(iii) Strong green links will be created through the new village which respond to the existing and proposed landscape features and create amenity space and significant potential for pedestrian and cycle connectivity, including links to nearby villages – eg. Deenethorpe, Upper Benefield, and the new Weldon Park development.
b) Ecology and Biodiversity
An ecological appraisal has been concluded including a desktop survey with full stakeholder engagement and a complete range of field surveys;
- Extended Phase 1 Habitat Survey;
- Badger Survey;
- Bat Activity and Emergence Surveys;
- Breeding Bird Survey;
- Brown Hare Survey;
- Botanical Survey;
- Dormouse Scoping Survey;
- Invertebrate Scoping Survey; and
- Reptile Survey.
Species and habitat diversity at the Airfield are restricted with key features being the airfield infrastructure and ancient woodland blocks in the wider landscape. Notable species include brown hare, skylark and lapwing. Over such a large site and the wider Deene Estate there are significant opportunities for major biodiversity gains through habitat enhancement and creation arising from a comprehensive green infrastructure strategy and programme. These habitat creation concepts include the following;
- Planting some 35ha of new woodland to buffer ancient and SSSI woodland on the periphery of the airfield to connect two woodland blocks.
- Creating some 80ha of parkland grassland and meadows that will provide the open character habitats for the skylark, lapwing and brown hare currently present both enabling expansions in these populations or use by additional notable species.
- Wetland creation as part of a SUDS drainage system and habitat creation works to provide wet meadow, wet woodland, permanent and ephemeral water bodies, ditches and connection to the Willow Brook.
- Willow Brook water course and ecosystem improvements including; flooding of riparian grassland for water quality and habitat; creation of pooled areas for water slowing/ silt removal; and creation of rifle gravel fast flowing areas for habitat and species interest.
With the space available at the Deenethorpe Airfield site there are several options available for habitat creation and how it can overlap and complement the creation of public access routes and areas, drainage systems, productive areas and commercial farming.
The support of the Brudenell Estate further extends the potential of the enhancements for biodiversity through connections to the wildlife friendly farming initiatives in practice on the wider estate.
There are no overriding constraints to the garden village proposal. On the contrary this is a major opportunity to meet, for example, Natural England’s and Core Strategy policies and aspirations for implementation of high quality, well-connected and accessible green spaces, significant biodiversity enhancement through the creation of new habitats and key contributions to Rockingham Forest and Nene Valley Nature Improvement Area objectives.
A Landscape and Ecology Management Plan will provide strong benefits through long-term sensitive management of existing and proposed biodiversity over an extensive area.
c) Flood Risk and Drainage
A Phase 1 Flood Risk Assessment (FRA) and Drainage Study has been undertaken.
The FRA considers the potential flood risk to the development and the potential risk posed by the garden village development to areas downstream of the site.
The site is located in Flood Zone 1 (lowest risk) and therefore has a less than 0.1% probability of flooding – it is a preferred location for new development on this issue. Surface water on site will be managed through a sustainable urban drainage system. Based on the scale of development envisaged this will need a total capacity of approximately 39,000m3 on site. The site can easily accommodate this volume and these water features will be designed into the garden village master plan to maximise green infrastructure and ecological benefits.
The site will ultimately drain to the east via Glapthorn Brook and to the west via Willow Brook. In order to enhance water quality, a series of reed beds will be established on site prior to discharge and a scheme for the Willow Brook will be brought forward in consultation with Environment Agency in line with Water Framework Directive objectives.
Hydraulic modeling has been commenced to confirm a suitable solution for foul drainage.
d) Transport and Access traffic and access strategy
The Airfield site is well related to the A43 and A427.
Ongoing appraisal work has been undertaken for the North Northamptonshire Core Strategy augmented by additional studies commissioned by the Deenethorpe Airfield Partnership. The site-specific analysis is based on an agreed set of traffic surveys and utilises the Northamptonshire Strategic Transport Model. Preliminary conclusions confirm that the Airfield proposal can be accommodated subject to minor improvements to a small number of locations on the A43 based on a design year of 2031.
Options for accessing the proposal have been evaluated in discussion with the County Highways Authority. A primary access to the A43 (a roundabout proposal) with a secondary (ghost-island) link to A427 is the agreed in-principle access strategy, confirming that the site can be accessed in a safe, viable and deliverable way.
The status and detail of the main route through the garden village is the subject of ongoing evaluation, mindful of proposals in the wider area.
The Airfield location adjacent A427 benefits from a high quality and frequent bus service – the X4 – which runs between Peterborough and Kettering via Oundle and Corby centres. The operator supports the prospect of diversion through the Airfield site to serve the new Garden Village. Transport choice and convenient connections to local and higher order facilities will, therefore, be available from the outset. The potential for additional local shuttle bus services to be introduced as the garden village progresses is also being examined.
Pedestrian and cycle routes
The new village will include a full range of day-to-day services and facilities, employment opportunities and excellent access to attractive surrounding countryside. A pleasant and safe footpath and cycle network will form a core component of the garden village design to ensure that people can readily connect within the garden village without the need to use a car. It is important too, that convenient pedestrian and cycle routes are provided to connect with Corby, Oundle and existing villages. Detailed consideration is already being given to the routes to main destinations as part of Neighbourhood Plan and Working Party assessment and discussion.
Garden village design
The master planning and engagement processes will include the transport and access considerations above to ensure, for example, that the garden village is suitably connected to the strategic road network and the layout of the primary roads through the development provides the best route for bus access. It is also important that the comprehensive network of pedestrian and cycle routes will be integrated with the extensive green infrastructure proposals providing attractive green links.
e) Archaeology and Cultural Heritage Assessment
A desk-based heritage appraisal of the site and surrounding area has been concluded having consulted the available archaeological historical and cartographic evidence for the site and surrounding area. The evidence has confirmed that there are no Scheduled Monuments, or Grade 1 and II* listed buildings within a 1km search area. Deene Park, a Registered Park and Garden, lies some 600 metres to the northwest.
The site is currently used for agriculture, with remnants of its former use as a military airfield still surviving. The site was originally utilised as a United States Air Force bomber base, which was operational from 1943-1945 and subsequently used as an RAF training base. Many of the former buildings including the control tower have been removed.
The garden village will have limited impact on archaeological or wider cultural heritage assets.
The cultural heritage related to the former airfield use is a key influence on the footprint and layout of the new garden village. As part of the development framework concept, the main runway is retained as a major public amenity and the subsidiary runways respected in the Movement Framework of the Master plan. This historic interest has played a significant part in developing the master plan from the earlier conceptual work (Appendix 1 – appendix 1 p4).
f) Ground Conditions
A Phase 1 desk-based assessment has been carried out which examines the geoenvironmental, geological and geotechnical settings of the site. Potential environmental and geotechnical constraints to the proposed development are identified and discussed. Recommendations for prospective remedial/protective measures and/or future design considerations, which could be required as part of the development have also been set out.
Historically the site was used as a WW2 bomber airfield. The records show several identified buildings/areas indicated as fuel storage areas, a ‘technical site’, bomb dump and gun range, together with various buildings of unidentified use. The site was previously and, in parts, subsequently used for agriculture. Part of the overall site remains an active airfield and an area of the site is also used now for caravan storage. The site has experienced some demolition and made ground is known to be present. In addition, several ponds have previously been in filled with unknown material as part of the Airfield construction and operation.
The nature of the made ground is not known at this stage and will require intrusive investigation. Airfield operations can result in several sources of contamination and there could be sources of ground gas, for example, from made ground deposits. There is no reason, at present, to suspect that this is a matter of any particular concern for the site, although detailed investigations will be required as a matter of course.
The constraints identified are common to many brownfield sites and will be addressed as part of the mast planning and planning approval processes. There will be a requirement for intrusive investigation, a detailed risk assessment and an appropriate remediation strategy.
The availability and capacity of existing utility services have been assessed. No major constraints have been identified but some works will be required to create additional network capacity.
- Foul drainage: Anglian Water has requested that additional hydraulic modeling is carried out to assess the effect on the existing network.
- Clean water supplies: Anglian Water confirms that an existing 6”clean water main runs directly through the centre of the garden village site north to south. Two connection points have been identified.
- Gas supplies: National Grid has confirmed that the nearest connection point with sufficient capacity for the site is a main located 2.5km to the south-west, on Corby Road. No diversions or easements are required.
- Electricity supplies: Western Power Distribution has provided budget costs to supply the site with electricity and costs for prospective diversion of overhead and underground cables located within the site. A substation will be required.
- Telecommunications: Diversion may be required for the relocation of BT Openreach underground and overhead cables which enter the site from both north and south. No Virgin Media diversions are anticipated.
h) Renewable Energy and Carbon Reduction Appraisal
A preliminary renewable energy and carbon reduction appraisal has been undertaken which assesses how the garden village will meet the Policy 14 requirements in this regard.
The appraisal considers the resources available to implement renewable energy technologies – both as building integrated and as stand-alone options to serve the community. Policy 14 requires a minimum of 80% of the energy requirement to be from renewable and low carbon sources. The appraisal identifies that this is achievable. Indeed it is possible to generate 100% of the development’s energy requirement just from a stand-alone solar PV facility and a biomass-fuelled combined heat and power plant (CHP) linked to a district heat network. The use of a biomass CHP could provide an opportunity for waste arising associated with forest management including major tree planting within the immediate vicinity of the site.
The Garden Village can achieve exemplary standards of design in this regard incorporating low and zero carbon design methodologies wherever practical. This will include the use of thermally efficient materials and architectural design to maximise the benefit from solar radiation, minimise air leakage and reduce thermal bridging heat loss routes.
The initial assessment concludes that the Garden Village has excellent potential (particularly because of its scale, space and single ownership) to utilise renewable and low-carbon technologies to achieve the renewable energy generation and energy efficiency requirements of Policy 14.
i) Agricultural Land Quality
The soils and agricultural quality of land at Deenethorpe Airfield have been assessed. The assessment focuses on an area of about 68 hectares ( from the overall 150-hectare Airfield ) where the built form of the Garden Village is sited and a further 7-hectare access corridor to the A43.
The soils, which belong to the Hanslope series and the Faulkbourne series, have high clay content. This allows them to retain large amounts of water and consequently limits the agricultural quality of the land to Subgrade 3b and Grade 4 due to excessive wetness and droughtiness. None of the land within the surveyed area is classed as best and most versatile.