Flood Risk Assessment

Transcription

1 15T788 Proposed Lidl Store, Stanley Street, South Shields 07 December 2015 Prepared By Billinghurst George & Partners Waterloo House, Teesdale South, Thornaby, Stockton on Tees TS17 6SA Tel: , Fax: E: Suite 58 Design Works, William St, Felling, Gateshead, NE10 0JP Tel: , FAX: E:

2 Project: Proposed Lidl Store, Stanley Street, South Shields Client: Lidl LLFA: South Shields Council BGP Job No: 15T788 Document Checking: Prepared By: R Lee Checked By: J Conway - Bsc CEng MICE Issue Date Status Checked for Issue /12/15 Planning 2 P a g e

3 CONTENTS 1 Introduction 2 Development Description and Location 3 Definition of the Flood Hazard 4 Probability of Flooding 5 Climate Change 6 Detailed Development Proposals 7 Flood Risk Management Measures 8 Off-Site Impacts and Residual Risks 9 Conclusions APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H Site Location Plan Proposed Site Layout BGP Drainage Strategy Plan EA Flood Map Northumbrian Water Records Topographic Survey Borehole Location Plan Reference Documents List 3 P a g e

4 1. Introduction Lidl UK GmbH have appointed Billinghurst George & Partners (BGP) to prepare a for the proposed Lidl Store off Stanley Street, West Harton, South Shields (see Appendix A and B). This report has been prepared to supplement the planning application. This report has been prepared in accordance with the requirements of The National Planning Policy Framework (Department for Communities and Local Government March 2012) [The Framework] and the Planning Practice Guidance to the National Planning Policy Framework Website (Launched 6 th March 2014) [The Technical Guidance]. Specific Areas of consultation and information gathered for the preparation of the report are as follows: 1 A site visit has been carried out. 2 Topographic Survey (Landform Surveys June 2014) 3 South Tyneside Council Level 1 Volume 1 & 2 Strategic [SFRA] report (JBA Consulting February 2011) has been reviewed. 4 The Environment Agency Flood Map information has been reviewed. 5 Northumbrian Water have been consulted and their records are included. 6 Preliminary Borehole Logs 4 P a g e

5 2. Development Description and Location The proposal is to construct a new Lidl store building together with associated car parking and infrastructure on a brownfield site that is currently used as an existing Lidl store together with a former care home, Oakdale Lodge. The development site occupies an area of 0.82 hectares and the National Grid Reference for the centre of the site is E , N The site is located in West Harton, South Shields. The site is bounded by South Dene Road with residential housing to the North round to the West, the B103 to the East and a public house and community centre to the South. A site location plan is included in Appendix A. The designation for the scheme is Building used for shops, which has a vulnerability classification of Less Vulnerable as defined in Table 2 of the NPPF Technical Guidance. The development is consistent with the Local Development Documents and the Local Planning Authority are consultees during the design development stages. The involvement of the Local Authority in the design development process demonstrates that the Sequential Test has been applied in the selection of this site for this development type. 5 P a g e

6 3. Definition of the Flood Hazard 3.1. Tidal Flood Risk: The site is 3.3km from the sea and located at an elevation of approximately 20-21m AOD. It is therefore considered that the site will NOT be affected by flooding from the sea. The risk of flooding from tidal sources is categorised as LOW Fluvial Flood Risk: The nearest named watercourse is the River Tyne (Main River), which is located 1.4km North of the site. The watercourse runs from West to East along the North of South Tyneside. Figure 1 Environment Agency Flood Map for Planning The Environment Agency flood map (Figure 1 and Appendix C) shows that the site is unaffected by this watercourse. The entire site is located within Flood Zone 1 which is 6 P a g e

7 categorised as having less than 0.1 per cent (1 in 1000) chance of flooding each year. The South Shields Council Strategic Volume 2 (SSC SFRA V2) states that the risk from tidal and fluvial flood risk from the River Wear are low and relatively few properties are at risk. The risk of flooding from fluvial sources is categorised as LOW Overland Flood Risk: Intensive rainfall, often of short duration, that is unable to soak into the ground or enter drainage systems can run quickly off land and result in localised flooding. The proposed building finished floor levels will be designed slightly higher than final ground levels and will direct overland flows towards the curtilages. South Dene Road runs along the entire Northern and Western boundaries and contains a number of road gullies which are positively drained by either Highway drainage or via the adopted Combined Northumbrian Water sewer system (see Appendix E for NWL records). The site is unlikely to be affected by overland flows from this area. The B103 Road runs along the entire Eastern boundary and contains a number of road gullies which are positively drained by either Highway drainage or via the adopted Combined Northumbrian Water sewer system (see Appendix E for NWL records). The site is unlikely to be affected by overland flows from this area. Stanley Street runs along the entire Southern boundary and contains a number of road gullies which are positively drained by either Highway drainage or via the adopted Combined Northumbrian Water sewer system (see Appendix E for NWL records). The site is unlikely to be affected by overland flows from this area. 7 P a g e

8 Figure 2 Environment Agency Surface Water Flooding Map for Planning The Environment Agency Surface Water Flooding Map (Figure 2 below) indicates that a small area within the site to have a Low potential for surface water flooding. This appears to be caused by a low point within the service/delivery ramp to the West of the store. The lower levels of this part of the site will be adequately drained from this area in to the revised drainage proposals for the new development. See appendix C It is unlikely that the site will be affected by overland flooding from any of the surrounding areas. The risk of flooding from overland sources is therefore categorised as LOW Groundwater Flood Risk: Groundwater flooding occurs when water levels in the ground rise above surface elevations. It is most likely to occur in low lying areas underlain by permeable rocks. 8 P a g e

9 Over the majority of the site the Made Ground comprises hardstanding over subbase type materials of crushed stone, over gravel of brick and stone and disturbed sandy gravelly clay with fragments of brick and stone. The deeper Made Ground on the western side of the site comprises predominantly disturbed clay or sand with anthropogenic debris of brick, concrete, sandstone, pottery, glass, timber and ash. The deeper made ground on the western side of the site may possibly relate to historic activity including rail lines on this portion of the site. The natural deposits were relatively uniform across the whole site, including below the area of the proposed store, comprising firm becoming stiff brown, mottled grey, slightly sandy gravelly clay with fragments of coal. The gravel content of the clay was noted to increase from depths of approximately 2.00m bgl s. However, a band of clayey sandy gravel was encountered within TP01 from a depth of 2.00m to 3.40m bcgl s. The majority of the investigation positions remained dry on completion. However, some isolated water ingresses were noted at the base of the made ground within TP04 and TP05, within the gravel layer within TP01 and at approximately 2.00m in BH02. Based upon these observations a shallow continuous water surface (water table) is not anticipated to be present below the site. Drainage and perched water with the more permeable layers. It is unlikely that the proposed site would be affected by groundwater due to the type and nature of soil material and the likely depth of the water table. The risk of flooding from ground water is therefore categorised as LOW Flooding from Sewers: The Northumbrian Water (NWL) sewer records show that South Dene Road and Stanley Street, along the Northern and Southern boundary of the site, are positively drained by the combined NWL sewers. Any flooding of these sewers would likely be retained within the kerb line of the respective residential developments and would not affect the proposed site. 9 P a g e

10 The NWL combined sewer within the site will need to be abandoned. Discussions with NWL will be required to approve this. The B103 road to the East of the site is also positively drained by the combined sewer that runs South to North falling away down Stanhope Road. Any flooding of these sewers would likely be retained within the kerb line of the respective residential developments and would not affect the proposed site. Based on the above the risk of flooding from sewers is categorised as LOW Artificial Source Flood Risk: Based on the Environment Agency map Risk of Flooding from Reservoirs the site is not at risk from any artificial sources such as reservoirs. The risk of flooding from artificial sources is categorised as LOW. 4. Probability of Flooding The South Shields Council Level 1 Strategic has been examined and the Environment Agency maps reviewed (see Appendix D and F). The site is identified as being in Flood Zone 1 as categorised by the National Planning Policy Framework (NPPF) and Technical Guidance. Flood Zone 1 describes the land assessed as having a less than 1 in 1000 annual probability of river or sea flooding in any one year. The previous section describes other flood hazards and the risk they pose to this project. Based on the previous section the overall assessment of the probability of flooding to the site is LOW. 5. Climate Change NPPF Planning Practice Guidance website provides information on the impacts of climate change, which include sea level changes, river flash flooding and more frequent high intensity, short-duration rainfall. 10 P a g e

11 As concluded previously the risk of flooding from the sea and rivers is low. The risk of flooding from land again is low; both are, therefore unlikely to be affected by climate change. 6. Detailed Development Proposals Refer to Appendix B for the Proposed Site Layout. The proposal is to construct a new Lidl store building together with associated car parking and infrastructure on a brownfield site that previously contained a bus depot. The topographic survey indicates that existing connections from the site to the Northumbrian Water adopted sewer network exist. These existing connections will be utilised where possible. It is expected that the existing surface water discharge rate into the public sewerage system will need to be reduced. Following the publication of Written Statement HCWS 161 and the DEFRA Non-statutory Technical Standards (March 2015) which encourages planning authorities to restrict flows to as close to Greenfield rates as far as is reasonably practicable, but should not exceed the rate of the discharge from the site prior to re-development. Pre planning advice received from David Rogerson at South Shields council on stated that The development should aim for a minimum reduction in surface water run off rates of 50% to what is currently discharged, and if possible aim to reduce run-off to greenfield rates of up to a 1 in 100 year storm even considering climate change Any flows above the discharge rate will be kept on site within attenuation storage. The drainage proposals for the site is covered within the BGP Drainage Philosophy report. The plan of the drainage proposals is included in Appendix C for reference. 7. Flood Risk Management Measures 11 P a g e

12 As stated in previous sections, the site is not at risk from flooding. All impermeable areas will be positively drained via a suitable drainage system that will incorporate typical gravity drainage systems and attenuation of flows. 8. Off Site Impacts The proposals for this site should not increase the flood risk elsewhere off site for the following reasons: - The total flow off site will be reduced by 50% or greater and attenuated for the 100 year storm event plus 20% climate change. The impermeable areas within the site will be positively drained via a proposed drainage network. Therefore any surface water flows will be prevented from reaching adjacent sites. 9. Conclusions From the above analysis it can be seen that the risk to the proposed Lidl Store development on land off Stanley Road, South Shields is LOW from all forms of flooding as categorised in the Framework and the Technical Guidance and confirms the Flood Zone designation for the site. The proposed uses of land are appropriate in this Flood Zone. (Tables 1 & 2 the Technical Guidance. This report has been prepared with reference to the information available at the time of writing. The summary and recommendations may be revised upon receipt of additional or further information. 12 P a g e

13 Report No: 15T788/FRA Report Title: Proposed Lidl Store, Stanley Road, South Shields, Tyne and Wear Prepared by: Richard Lee Date: 07/12/2015 Checked by: J Conway BSc CEng MICE Date: 07/12/ P a g e

14 Appendix A Site Location Plan 14 P a g e

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16 Appendix B Proposed Site Layout 15 P a g e

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18 Appendix C BGP Drainage Strategy Plan 16 P a g e

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20 Appendix D EA Flood Map 17 P a g e

21 Flooding From Rivers and Sea Flooding from Surface Water

22 Appendix E Northumbrian Water Records 18 P a g e

23 UPVC 6 CICL 8509 UPVC VC 1.04 MDPE " 150 VC 8512 UPVC VC VC UPVC 4" MDPE 225 VC VC " 225 VC 1.43 WO 8602 UPVC 63 SOUTH DENE " MDPE 225 VC m 225 VC VC 300 CO 150 VC VC El Sub Sta CO H 150 Council Offices 300 CO 150 VC BELLE VUE PC to VC 1 CRESCENT HPPE v " m CICL " WO v CICL TCB 4" H Bank VC H M " m FC " FC STANHOPE ROAD S15A " 2 to " 378 LB CICL " " 511 BRINKBURN STREET WO " H " " 150 VC 225 VC 225 VC VC NOMH NOMH MDPE WO 150 VC SOUTH DENE 4" H H Community Centre Tennis Courts H 2.19 Waste Water - NWL Responsibility Private/Non NWL Combined Combined 150 VC UPVC STANLEY STREET Foul Foul Surface Surface Treated Eff Trade Eff Untreated Eff Watercourse Overflow Oakdale Lodge 6" FC UPVC Medical Centre 3" M Proposed Combined Foul Surface TCB VC FC " 3 PH 9" 9405 UPVC VC CICL 21.3m 2.93 CICL 9" CICL " 3" STRAKER TERRACE 3" CI 9403 WO 3.61 Bank 1.61 FC Water Network - Network Types Distribution Treated Raw Fire Supply Private FC H 4" AB Asbestos Abandoned Out of Comm BRINKBURN STREET " User : CAPEL Title : Centre Point : , Date : 02/12/ :55:13 Map Sheet : NZ3564NE Paper / Scale : A4@1:1250 The material contained on this plot has been reproduced from an Ordnance Survey map with permission of the controller of H.M.S.O. Crown Copyright Reserved. Licence No. WU The information shown on this plan should be regarded as approximate and is intended for guidance only. No Liability of any kind whatsoever is accepted by Northumbrian Water, it's servants or agents for any omission. The actual position of any water mains or sewers shown on the plan must be established by taking trial holes in all cases. In the case of water mains 10 m Northumbrian Water must be given two working days notice of their intention to excavate trial holes. Private connections are not shown but their presence should be anticipated. WARNING...Where indicated on the plan there could be abandoned asbestos cement materials or shards of pipe. If excavating in the vicinity of these abandoned asbestos cement materials, the appropriate Health & Safety precautions should be taken. Northumbrian Water accepts no liability in respect of claims, costs, losses or other liabilities which arise as the result of the presence of the pipes or any failure to take adequate precautions. Emergency Telephone Number:

24 Appendix F Topographic Survey 19 P a g e

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26 Appendix G Borehole Location Plan 20 P a g e

27 DO NOT SCALE Key BH Windowless Sampling Borehole TP Mechanically Excavated Trial Pit WS 1 CLIENT: Lidl UK GmbH PROJECT: Lidl Tyne Dock TITLE: Site Investigation Location Plan DESIGN / DRAWN: MWH PROJECT NO: DATE: December 2015 DRAWING NO: Grey Street, Newcastle upon Tyne, NE1 6EE Tel: +44 (0)

28 Appendix G Reference Documents List The National Planning Policy Framework (March 2012) Communities and Local Government The Technical Guidance to the NPPF (March 2012) Communities and Local Government Guidance Note 1 Environment Agency Sunderland City Council Level 1 SFRA Report (June 2010) JBA Consulting 21 P a g e