UTILITIES APPRAISAL

Prepared by WSP JULY 2012 CONTACTS/THE TEAM

CONSORTIUM

CONSULTANTS

Sellwood Planning Ian D Bull Stoughton Cross House, Somerset, BS28 4QP 1 Mountbatten Way, Lees, Ashford, T. +44 (0)1934 712041 F. +44 (0)1934 712118 TN25 6PZ T. +44 (0)1303 814153 M. +44 (0)7738 584221

WSP - Ecology Grontmij WSP House, 70 Chancery Lane, London WC2A 1AF 36-40 York Way, London N1 9AB T. +44 (0)20 20 7314 5000 F. +44 (0)20 7314 5111 T. +44 (0)20 7843 3140 F. +44 (0)20 7587 3839 www.wspgroup.com www.grontmij.co.uk

WSP - Heritage and Archaeology Mountbatten House, Basing View, Basingstoke RG21 4HJ T. +44 (0)1256 318 800 F. +44 (0)1256 318 700 www.wspgroup.com

WSP - Sustainability WSP House, 70 Chancery Lane, London WC2A 1AF T. +44 (0)20 20 7314 5000 F. +44 (0)20 7314 5111 www.wspgroup.com

WSP - Transport Mountbatten House, Basing View, Basingstoke RG21 4HJ T. +44 (0)1256 318 800 F. +44 (0)1256 318 700 www.wspgroup.com John Thompson & Partners 23-25 Great Sutton Street, London EC1V 0DN T. +44 (0)20 7017 1780 F. +44 (0)20 7017 1781 www.jtp.co.uk

QM

Issue/revision Issue 1 Revision 1 Revision 2 Revision 3

Remarks First Draft

Date 12/01/2012 25/5/12

Prepared by M. Warner A. Atkinson

Signature

Checked by J. Greene A. Atkinson

Signature

Authorised by A. Atkinson A. Atkinson

Signature

Project number 11012761 11012761

File reference 2761/SERVSUM 2761/SERVSUM

Cover photograph courtesy of John Morton WSP Remediation, UK. Depicts a number of flow meters forming part of the most complex treatment system ever built by WSP Remediation thus far, encircling the main stadium at the 2012 Olympic Park.

WSP UK Limited | Registered Address WSP House, 70 Chancery Lane, London, WC2A 1AF, UK | Reg No. 01383511 | WSP Group plc | Offices worldwide

Contents

1 Introduction 4 2 Foul Water Drainage 5 3 Surface Water Drainage 7 4 Water Supply 9 5 Electricity Supply 11 6 Gas Supply 13 7 Pipelines 14 8 Telecommunications 15 9 Conclusions and Recommendations 16

Appendix A Site Location Plan – Figure 1

1 Introduction

1.1 BACKGROUND

1.1.1 WSP Development and Transportation has been appointed by a development consortium comprising Ward Homes (a Trading Name of BDW Trading Ltd), Pentland Homes, Hodson Developments and Malcolm Jarvis Homes to carry out a baseline utilities appraisal for development on land at Chilmington Green, South West Ashford, Kent, hereafter known as the site. 1.1.2 This report assesses the utility requirements to support the planning application for 5750 dwellings and schools and other associated developments. 1.1.3 As part of the work undertaken, WSP has assessed the supply of the site for the proposed 5750 dwellings and determined the upgrade works required. 1.1.4 The site is located south west of Ashford and bordered on the north west side by the A28 Ashford Road, on the south east by the Long Length Road and Tally Ho Road. Refer to Figure 1 – Site Location Plan, Appendix A. 1.1.5 The majority of the site consists of large areas of open arable, improved grassland and pasture land. Development within the site boundaries includes a small industrial estate, a farm area of agriculture buildings and many private dwellings. 1.1.6 Preliminary letters of enquiry were sent to the relevant Statutory Undertakers and Authorities requesting information on the location of existing services, the need for diversionary measures, capacities of existing networks and preliminary broad brush costs. In addition, consultation and meetings with Ashford's Futures regarding strategic utilities development local to the site and the Greater Ashford area has been carried out.

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2 Foul Water Drainage

2.1 EXISTING FOUL WATER INFRASTRUCTURE

2.1.1 Southern Water Services (SWS) records indicate an existing network of public foul sewers off-site. This network drains the existing development situated to the south and north of the development site. 2.1.2 The area to the south of the site around Stubbs Cross is drained via an off-site network of 150mm diameter sewers, to a pumping station on Magpie Hall Road (at the eastern edge of Stubbs Cross). In addition to this, the pumping station (PS) receives flows from the development extending east along Magpie Hall Road and the south-west along Tally Ho Road. Flows are pumped north to a second PS situated north of the junction of Chart Road and Millbank road. This second PS receives additional flows from areas to the north and north-east of the application site in the vicinity of Chart Road and Washford Farm Road. 2.1.3 There is an existing 150mm diameter foul sewer situated to the north of the application site, south-east of the junction of Chart Road and Mock Lane. This sewer drains via gravity north towards Ashford along Singleton Hill. 2.1.4 SWS has completed investment in K4 (2005-10) to provide trunk sewerage capacity required for new development in Ashford. 2.1.5 In addition, SWS has upgraded their Bybrook Waste Water Treatment Works (WWTW) to cater for capacity required for new development in Ashford. This treatment works employs waste to energy generation and as such provides the Chilmington Green proposals with a level of off-site carbon offsetting. 2.2 PROPOSED FOUL DRAINAGE

2.2.1 Based on Sewers for Adoption 6 th Edition load calculation methodology, peak foul flows generated by 5,751 residential units would generate flow of 266 l/s. This figure is a peak (factored by 6) flow and equates to a daily (24hr) flow of 3,485m3/day. It should be considered that this peak flow is likely to increase with the addition of other land uses, i.e. commercial, educational, etc. In turn this figure will reduce if water efficiency measures are used on this site. 2.2.2 Proposals for an on-site waste to energy treatment works are not supported by Southern Water on the basis that their existing infrastructure has capacity available and the downstream Bybrook WWTW already employs waste to energy generation. It is understood that the Environment Agency also do not support proposals for an on-site WWTW.

Main Development

2.2.3 SWS confirmed there is existing capacity within their sewerage infrastructure and at Bybrook WWTW to support the entire 5,750 property development (plus supporting development) due to recent upgrades which were paid for by the last business plan (AMP period) and therefore covered by the infrastructure payment. 2.2.4 SWS has identified a suitable connection point for the site where capacity exists in in the Bucksford Park area between the A28 and B2229, roughly 1.5km north of the site.

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2.2.5 Owing to the topography, around 3 to 4 pumping stations will be required on- site to achieve connection to off-site sewers, depending on final layout and phasing. Potentially this may see smaller individual pumping stations on each development parcel on-site, or a strategic approach to the site may be taken.

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3 Surface Water Drainage

3.1 EXISTING SURFACE WATER HYDROLOGY

3.1.1 The site generally falls in elevation from north to south with the exception of the Brisley Farm area which falls east. A review of OS mapping and Wallingford FEH catchment descriptions confirms that the site straddles two main catchment areas: the River Stour to the east; and River Beult to the west. 3.1.2 There are numerous ponds, ditches and springs within the site. These features form the hydrological source for tributaries running off-site to the east (to the River Stour) and west (to the River Beult). 3.1.3 The topography of the areas immediately north and north-east of the site ensures that surface water run-off from these areas is routed through the site as part of the drainage regimes for both the Rivers Beult and Stour. Subsequent hydraulic assessment which need to take account of these off-site flows. 3.1.4 Historically, there has been a number of flooding incidents in Ashford associated with the Stour. As a result, Ashford Borough Council has produced a Draft Sustainable Drainage Supplementary Planning Document (SPD) adopted in October 2010 which builds on existing Core Strategy Policies. This document sets out Ashford Borough Council’s requirements for SUDS design including maximum engineered discharge rates. 3.1.5 In the case of Chilmington Green which drains to both the Rivers Beult and Stour, post development discharge rates will be restricted to reduce the risk of flooding downstream of the development. The Sustainable Drainage SPD states that there is a maximum discharge rate of 4 l/s/ha to the Stour and if possible, 4 l/s/ha to the Beult is encouraged, otherwise no more than 6 l/s/ha unless unavoidable. 3.1.6 The betterment provided by this over attenuation will require larger storage volumes within proposed basins and SUDS features on-site. 3.1.7 The proposed surface water drainage strategy seeks to reduce discharge rates in-line with the Ashford SUDS SPD. 3.1.8 A fundamental principle of sustainable development in terms of flood defence is the reduction of surface water run-off from new developments. 3.1.9 The Environment Agency’s national policy for sustainability requires that rainfall run off from new developments is limited to that of existing run off rates. 3.1.10 Any increase in run off above the allowable discharge limit must be attenuated on-site. Therefore an assessment of attenuation storage volumes has been carried out for a range of impermeability factors and run off restrictions (i.e. existing greenfield rates and 4 l/s/ha). 3.1.11 The inclusion of source control SUDS measures within the development could provide a number of benefits such as: additional control of run-off from the site; minimising the impact of the development on flood risk in other areas; increasing wildlife and amenity value; and contributing to the improvement of water quality of surface water run-off discharged from the site, which would contribute to protecting the water quality of the receiving watercourses. 3.1.12 A desktop review of known geological characteristics for the site indicates that in general the site is underlain by clay with an area of alluvial deposits in southern parts of the site. In terms of the potential for application of SUDS on-site in the future it is likely

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that infiltration SUDS would only be achievable in the alluvial area subject to groundwater levels. Therefore, the remainder of the site is likely to be unsuitable for infiltration and thus surface water would require attenuation on-site. Attenuation may be achieved through a range of measures including ponds, swales, green roofs and tanked porous pavement. 3.2 DRAINAGE CONSTRAINTS

3.2.1 The key drainage constraint on-site will be that of off-site restriction. However the topography of the site in relation to potential point of discharge also needs to be considered. 3.2.2 Areas along the south east boundary of the site (along Long Length Lane) and along the south west boundary of the site (north-west of Criol Road) are relatively flat and are also low points on the site. Given the topography within these areas a gravity drainage solution may prove difficult to achieve. Land raising to provide suitable levels should be considered at this time as a potential option. 3.2.3 With respect to the area of flood risk in the east and south of the site, the flood risk extent would need to be considered when choosing a suitable location and form for attenuation storage. 3.2.4 SWS’s view is that all surface water systems with SUDS will be adopted by the SAB under the Flood and Water Management Act provisions, whether or not they ultimately connect to existing SWS infrastructure. Guidance relating to SUDS and surface water sewer adoption is currently unclear and further clarification will be required. 3.3 DRAINAGE STRATEGY

3.3.1 Refer to the WSP PPS25 Flood Risk Assessment report for details of the drainage strategy. 3.3.2 In summary, SUDS will be utilised on-site in order to reduce the surface water discharge rate from the site to 4 l/s/ha. This will reduce the risk of flooding off-site while providing ecological and amenity benefits on-site.

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4 Water Supply

4.1 EXISTING WATER SUPPLY INFRASTRUCTURE

4.1.1 Historically Mid Kent Water was the statutory undertaker for water supply in Ashford, however, in December 2007, South East Water (SEW) and Mid Kent Water merged. South East Water is now responsible for water supply in this area. 4.1.2 A major new SEW transfer main has recently been completed which secures water supplies for Ashford’s growth. The pipeline brings treated water from Bewl Reservoir to Ashford and supplies up to 6 Ml/d (6000 m 3/day) to the Ashford growth area. 4.1.3 This new main crosses part of the AAP Boundary Area and therefore will constrain development along its route. However, it does not cross land identified for development in the Master Plan. 4.1.4 In addition there are various smaller supply mains which supply the existing developments within the site boundary. 4.2 PROPOSED WATER SUPPLY

4.2.1 SEW has confirmed that they are able to supply the site with potable water. 4.2.2 The water required by the development is available from the new SEW transfer main, however; supplies cannot be made directly to this main as it pumps periodically in order to top-up service reservoirs in the Ashford area. 4.2.3 SEW confirmed in a meeting with them on 16 November 2010 & then in an email on the 13 March 2012, the following advice has been given by SEW:

 SEW have sufficient strategic bulk supplies to cater for this development.

 Up to 335 properties can be supplied from the existing network adjacent to the northern boundary of the site with minor reinforcement to their existing network. This area is supplied from Potters Corner reservoir to the north of Ashford.

 The reservoir to the east of the site can supply an additional 2000 properties at the site. A new link to the site from this reservoir would be required.

 Additional demand will have to come from a proposed new service reservoir 4.5km from the site. 4.2.4 Due to level supply pressure differences between the Potters Corner and Kingsnorth supply zones, it is suggested that the 335 property capacity from the north be used to supply properties at the highest elevation on the site. This approach will reduce the amount of pumping when/if required from other zones.

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Main Development

4.2.5 Subsequent to meeting with South East Water, they have further assessed the site requirements but have been unable to provide details for the full development proposals. The information provided caters for the first 3,500 units. The information provided by SEW includes:

 In order to supply 3500 unit at Chilmington Green, connections to three of their service reservoirs will be needed. These are situated to the north west (adjacent to the A20 Maidstone Road), Kingsnorth (to the east) and a third proposed reservoir approx. 4.5km to the south east of the site.

 The majority of the site will be supplied from Kingsnorth.

 The developer will be required to pay a contribution towards the new reservoir and off-site mains.

Brisley Farm

4.2.6 South East Water has stated that Brisley Farm may be accommodated for separately without the need for off-site mains reinforcement

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5 Electricity Supply

5.1 EXISTING INFRASTRUCTURE

5.1.1 Plant plans provided by UK Power Networks Services (UKPN) (formerly EDF Energy) highlight the presence of low voltage (LV), high voltage (HV) and extra high voltage (EHV) located on or adjacent to the site. Plans also highlight the existence of a number of substations situated on and adjacent to the site. 5.1.2 UKPN Plans indicate an overhead (O/H) 132kV (EHV) cable traversing the eastern corner of the site. This (O/H) cable enters the site 150m south-west of Willowded Farm and travels (via 3 No. suspension towers) north-west to exit the site to the west of Chart Road. 5.1.3 UKPN Plans indicate an underground (HV) supply cable traversing the site. This cable enters the site at the site's southern boundary and runs north-east along Criol Road and supplies the existing development in the vicinity of Great Chilmington. This same cable continues to proceed north-east to Chilmington Green farm, which it re- orientates to the north-west and exits the site at the western boundary at the junction of Goldwell Lane and the Ashford Road. 5.1.4 UKPN Plans indicate an underground (LV) supply network servicing the existing development in the area of Chilmington Green in the centre of the site. 5.1.5 UKPN Plans indicate a (HV) cable off-site within Chart Road (off-site) which terminates at a sub-station situated at the site's eastern boundary at the southern end of Ploughmans Way. 5.1.6 UKPN Plans indicate a number of primary sub-stations on or adjacent to the site:

 65m south-east of the site at Stubbs Cross

 280m south-west of the site at

 Adjacent to the site's western boundary at the junction of Goldwell Lane and the A28 Ashford Road 5.1.7 The plant plans provided show locations of plant as installed. Alterations to road alignments and surface levels may not have been recorded and therefore the exact location of plant cannot be guaranteed. The charted positions cannot be accurately relied upon for excavation works and probing / hand dug trial holes will be required to accurately identify the positions of the laid services. 5.2 PROPOSED SUPPLY

5.2.1 UKPN has confirmed that they can supply the site and that it should be possible to provide some power to serve the first few houses without reinforcement of both the main site and Brisley Farm. The exact number will need to be confirmed at the time when a detailed design work strategy is set out.

Main Development Area

5.2.2 UKPN has provided a number of options which supply increasing amounts of power to the site. These options provide the possibility of phasing off-site upgrades in order to reduce initial costs to the developer. Option 1 – 200kVA connection from local network, comprising:

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 Establish 1No Secondary Distribution Substation at a suitable location on-site.

 Lay 2No. 11kV cables, ducted, approximately 200m to the existing HV main. Option 2 – 2.5MVA connection from Singleton Primary, Comprising:

 Establish 2No 11kV feeder circuit breakers at Richborough Primary.

 Lay 2No. 11kV cables, ducted, approximately 5,250m to the site.

 Establish 2No metered feeder CBs, complete with ancillary plant, at the site. Option 3 – 19MVA connection from Ashford Grid, Comprising:

 Establish 2No 33kV feeder circuit breakers at Ashford Grid.

 Lay 2No. 33kV cables, ducted, approximately 6km to the site.

 Establish 1No new primary substation at a suitable location on the customer’s site. 5.2.3 An on-site primary substation will require a typical area of 40m x 40m with access close to a main road. Brisley Farm 5.2.4 UK Power Network has provided a separate response regarding the Brisley Farm area of the development proposals. 5.2.5 UKPN have assumed connection to their HV network along Harrow Way with a load not exceeding 300kVA. 5.2.6 A substation will be required on-site, requiring land up to 5m x 5m with access from the highway.

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6 Gas Supply

6.1 EXISTING INFRASTRUCTURE

6.1.1 National Grid Records confirm that the areas to the east and north-east of the site are served by an existing gas network. 6.1.2 National Grid Records confirm the presence of an 18" High Pressure (HP) gas main traversing the southern portion of the site in an east-west direction. This main enters the site from the east approximately 80m north-west of the junction at Tally Ho Road and Maypole Hall Road. This main exits the site at the south-west boundary approximately 570m west of the junction of Tally Ho Road and Magpie Hall Road. 6.1.3 Correspondence from Scotia Gas Networks (SGN) confirms that the easement along the 18” HP Gas main is 6m in width, hence covering 3m on either side of the gas main. 6.1.4 A high pressure gas main is defined as a "Major Accident Hazard" by the HSE and therefore has consultation zones around the route of the pipeline. There will also be a Building Proximity Zone associated with the pipeline which depends on the pressure of the pipeline and the material of the pipe. This may mean that certain high density development may be precluded closer than 50-60m to the pipe. However, low density uses may only be restricted 12m from the pipe. 6.2 PROPOSED SUPPLY

6.2.1 From a strategic point of view there are no known major reinforcement works required for the Ashford gas supply network to accommodate the proposed expansion of south-west Ashford including Chilmington Green and Brisley Farm. 6.2.2 SGN has confirmed (December 2011) that there is sufficient capacity available from the 12” steel intermediate pressure main in Cuckoo Lane to serve the development proposals and that off-site reinforcement is not anticipated.

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7 Pipelines

7.1 HAZARDOUS PIPELINES

7.1.1 Esso, Mainline, BPA, GPSS, Total UK, Conaco Phillips, Manchester Jetline, Shell UK, Sabic UK, BPTSEP, BP GEO, E-ON UK, BP Explanation and Scottish Power have all confirmed that they do not have any pipelines on or within the vicinity of the site.

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8 Telecommunications

8.1 EXISTING INFRASTRUCTURE

8.1.1 BT plant records identify existing infrastructure, off-site along the Ashford Road to the west of the site, within residential areas east of the site and to the south of the site within the area of Stubbs Cross. BT plant records further identify existing plant on-site serving the existing development in the area of Chilmington Green. 8.1.2 BT recommends that mechanical excavators or bores are not used within 600mm of their apparatus. 8.1.3 BT Plans provide guidance on the location of their plant but cannot guarantee the exact position. BT should be instructed prior to any works on-site. 8.1.4 COLT and Fujitsu Tele Communications have confirmed the presence of a fibre optic cable within the boundaries of the site. This fibre optic cable enters the site along the north-west boundary at the junction of Magpie Hall Road and the A28 Ashford Road and exits the site at the junction of Magpie Hall Road and Long Length Lane. This cable is the main fibre optic cable from Folkestone to Paddock Wood. 8.1.5 Optilan and EasyNet have confirmed they have no apparatus located on-site. 8.2 PROPOSED SUPPLY

8.2.1 BT Openreach have stated that the development could be a potential flagship site for Fibre to the Premises (FTTP) which is currently scheduled to launch from 2012- 2013. This provides up to 100Mbit/s with trials of 1Gbit/s taking place in 2011-2012. 8.2.2 Due to the competitive nature of the telecoms market, new supplies can be readily provided to the site and are not a constraining feature in this location.

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9 Conclusions and Recommendations

9.1 CONCLUSIONS

9.1.1 The strategic reinforcement works for both water supply and foul sewage are now complete and do not constrain development proposals. As such, there are no strategic utility capacity constraints associated with serving the development site. 9.1.2 In order to make use of the available capacity from UKPN, Southern Water and South East Water, significant connecting infrastructure will be required.

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Appendices, Figures & Tables

Appendix A Site Location Plan – Figure 1