PROJECT No. RML 6994 SITE INVESTIGATION at STAR COURT
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Unit 10 Coopers Place Combe Lane, Godalming Surrey GU8 5SZ Tel: 01883 343572 Fax: 01883 344060 email: [email protected] Web: www.riskmanagementltd.co.uk PROJECT No. RML 6994 SITE INVESTIGATION AT STAR COURT, THAMES STREET, SONNING ON BEHALF OF MR MARK SAUNDERS July 2020 Risk Management Limited Registered Office: 344 Croydon Road, Kent BR3 4EX Registered in England 03752505 CONTENTS 1.0 INTRODUCTION & SCOPE OF WORKS 2.0 WALKOVER SURVEY 3.0 PHASE 1 ENVIRONMENTAL RISK ASSESSMENT 4.0 HISTORICAL MAPS 5.0 FIELDWORK 6.0 GROUND CONDITIONS 7.0 LABORATORY TESTING 8.0 DISCUSSION APPENDICES • EnviroCheck Report • EnviroCheck Plans • Historical Maps (10 Sheets) • Plates 1-4, General Site Photographs • Light Percussion Borehole Records (BH1-BH4) • SPT versus Depth Profile • Figure 1 - Trial Pit Record (TP1) • BRE 365 Percolation Test Calculation Sheets (SA1) • Falling Head Permeability Test Results Sheets (SA2-SA4) • Laboratory Test Results • Gas/Groundwater Monitoring Test Results • Messrs. Inspiration Chartered Architects Ltd, Site Plan, Project No. 17003, Drawing No. S_000.3 • Sketch Fieldwork Location Plan, Drawing No. RML 6994/1 Project No. RML 6994 Page 1 of 28 “Star Court”, Sonning July 2020 1.0 INTRODUCTION & SCOPE OF WORKS 1.1 This report has been prepared by Risk Management Limited under cover of Messrs. Inspiration Chartered Architects Limited’s e-mailed Instructions to Proceed, dated 29th June 2020. 1.2 The Client for the project is Mr. Mark Saunders. 1.3 The site under consideration is the residential property known as “Star Court” located off Thames Street, Sonning, Reading RG4 6UR. 1.4 The approximate six-figure grid reference for the centre of the site is 475760E, 175680N. 1.5 It is understood that the proposed development at this site will comprise erection of a new property and ancillary garage with habitable accommodation to the first-floor following demolition of the existing dwelling and garage plus associated landscape and an outdoor swimming pool. Further details of the development can be found on the appended Messrs. Inspiration Chartered Architects Ltd, Site Plan, Project No. 17003, Drawing No. S_000.3. 1.6 Risk Management Limited have now been commissioned to carry out an investigation into the site comprising both a Phase I, Non-Intrusive, Desk Study and a Phase II, Intrusive, Site Investigation. 1.7 The Desk Study comprises a Walkover Survey, an Environmental Disclosure Report, and Historical Map Search and covers the whole of the site. 1.8 It should be noted that the current Desk Study is designed for geo-environmental purposes only and does not include a Structural Survey, Ecological Survey, above ground or building Asbestos Survey or an Invasive Plant Survey for Japanese Knotweed, Giant Hogweed etc. 1.9 The Intrusive site investigation provides information on the sub-soil conditions at this site and the results of laboratory testing. 1.10 This report presents the work carried out and discusses the findings. Project No. RML 6994 Page 2 of 28 “Star Court”, Sonning July 2020 2.0 WALKOVER SURVEY 2.1 A Walkover Survey of the current property, and that of the immediate surrounding area, was carried out by Risk Management Limited on the 15th July 2020. 2.2 The site is an irregular shape in plan, covers an area of approximately 0.33ha and is generally flat with a slope down from south to north. Access to the site is gained via a shared tarmac access area off of Thames Street to the south. 2.3 The site consists of a large, generally square-shaped, parcel of land comprising the majority of the site with a gravel access driveway to the southern portion of the site. The driveway is bordered by flower beds and trees/shrubs and curves to the north east as the site opens. The gravel continues and surrounds a large two-storey brick-built property with a pitched tiled roof. The dwelling is generally rectangular with single-storey projections on the north-west flank and an entrance porch on the south-west flank. To the west, north and north-east of the dwelling are landscaped areas of grass, bordered by beds of trees/shrubs. To the south of the dwelling beyond the gravel driveway are retaining sleepers with a raised area of sparse trees. To the south-east of the property is a single-storey brick built outbuilding. 2.4 The north-eastern boundary to the current site is formed in part by a brickwork wall and a timber panel fence. Beyond this boundary are the grounds of another residential property. 2.5 The eastern boundary to the current site is formed by a brickwork wall and the outbuilding, beyond which are, again, the grounds of a residential property. 2.6 The southern boundary to the current site is formed by a timber panel fence. Beyond this boundary are the grounds of another residential property. 2.7 The western boundary to the current site is formed by the wooden entrance gates and is part undefined and part timber panel fence. Beyond this boundary is a forecourt area with garages and Deanery Lodge with Thames Street further beyond. 2.8 The north-western boundary to the current site is formed by a timber panel fence. Beyond the boundary are the grounds of a residential property. Project No. RML 6994 Page 3 of 28 “Star Court”, Sonning July 2020 2.9 On the site itself are drainage manholes to the rear of the dwelling. No evidence of other major services were visually evident during the Walkover Survey. 2.10 The site lies in a mainly residential location with Sonning High Street and the River Thames close by. 2.11 No visual, or olfactory evidence of contamination was noted during the walkover survey. 2.12 Plates 1-4, appended, show general photographs of the site at the time of the current Walkover Survey. Project No. RML 6994 Page 4 of 28 “Star Court”, Sonning July 2020 3.0 PHASE 1 ENVIRONMENTAL RISK ASSESSMENT 3.1 An Envirocheck Report was commissioned for the current site covering an area of up to 1000m from the centre of the site. 3.2 Only criteria within 250m of the centre of the site are discussed in detail below but full results of all the search criteria up to 1000m from the centre of the site are summarised within the relevant pages of the appended EnviroCheck Report. 3.3 From reference to the local Ordnance Survey mapping the nearest watercourse would be the River Thames which lies approximately 150m to the north-west of the current site at its nearest point. 3.4 The general hydraulic gradient for the catchment is assumed to be in a north-westerly or westerly direction towards the River Thames. Therefore, only potential sources of contamination to the south-east and possibly the east of the current site are considered likely to have any significant impact. Geo-Environmental Hazards 3.5 The following table summarises the potential geo-environmental hazards and mitigation measures for this site. Data Type Hazard Mitigation Measures for currently proposed development Landfill & Waste The Local Authority Landfill Coverage is designated as Gas monitoring Management Facilities Wokingham District Council and Oxfordshire County will be undertaken Council who have both supplied landfill data. There are as part of the no Licensed Waste Management Facilities, Registered, current Phase II Recorded or Historic Landfills, or Registered Waste intrusive site Transfer Treatment or Disposal Sites noted within the 0- investigation. 500m search band. There is one Potentially Infilled Land (non-water) entry within the 0-250m search band. This relates to unknown filled ground 57m to the east. Project No. RML 6994 Page 5 of 28 “Star Court”, Sonning July 2020 Local Authority Pollution There is one Local Authority Pollution Prevention and Contamination Prevention and Controls Control entry noted within the 0-250m search band. testing will be This relates to H. C. Motors located some 86m to the undertaken as south of the site and is for Waste Oil Burners. There are part of the current no further Local Authority Pollution Prevention and Phase II, Intrusive, Controls noted within the 251-1000m search band. contamination site investigation. Hazardous Substances There are no Hazardous Substances entries noted within None required. the 0-1000m search band. Coal Mining The site lies within an area which would not normally be None required. affected by coal mining activity. Collapsible Ground “Very Low Hazard” None required. Stability Compressible Ground “No Hazard” None required. Stability Ground Dissolution “Low Hazard” None required. Landslide Stability “Very Low Hazard” None required. Running Sand “Very Low Hazard” None required. Swelling or Shrinking Clay “Very Low Hazard” None required. Radon The site does not fall within shaded sections of Annexe None required. A of BRE Report 211 (2007) “Radon: guidance on protective measures for new dwellings”. Therefore, No Radon Protective Measures will be necessary in the construction of new buildings at this location Contemporary Trade There are no Contemporary Trade Directory Entries None required. Directory Entries noted within the 0-250m search band. The nearest Some active entry relates to a Breakdown and Recovery contamination service located some 567m to the west of the current testing will be site. undertaken as part of the current Phase II intrusive site investigation. Historic Contemporary There are no Historic Trade Directory Entries noted Some Trade Directory Entries within the 0-250m search band. The nearest historic contamination entry relates to Toiletries at Sheabutter Cottage some testing will be 325m to the south-east of the current site. undertaken as part of the current Phase II intrusive site investigation. Fuel Station Entries There are no Fuel Station entries within the 0-1000m None required search band.