Lustre Letter Template
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2nd Floor North The Fitted Rigging House The Historic Dockyard Chatham Kent ME4 4TZ t 01634 757 705 28/09/2020 e [email protected] Our Ref: 3626 - 200604 - SS w www.lustreconsulting.com Jean-Pierre Popat 2020 Group Enterprises Limited 177 Rushey Green Catford London IG7 5BQ Sent via email Dear Jean-Pierre, 150 HIGH ROAD – STATEMENT ON CONTAMINATION This Statement on Contamination has been prepared for the site clearance and development of a site located off High Road, in Chigwell, Essex, IG7 5BQ by Lustre Consulting Limited (Lustre) for 2020 Group Enterprises Limited (the Client). The purpose of this letter report is to provide a high-level overview of the contamination risk of this property. The site, rectangular shaped in plan, is centered at National Grid Reference 543480, 192630 and occupies an approximate area of 0.22ha as shown in Figure 1. The site currently comprises a low-rise residential dwelling with front drive/garden and a large rear garden, complete with a pond and small swimming pool. The subject site is located within a residential area. Figure 1: Site Location Plan Registered Office: 2nd Floor North, The Fitted Rigging House, The Historic Dockyard, Chatham, ME4 4TZ Registered in England & Wales Registered No. 7111541 [Lustre Consulting Limited], 9911815 [Lustre Consulting (South West) Limited] Proposed Development Redevelopment is proposed involving the clearance of the site and subsequent construction of a large detached residential building at the front of the site within the general location of the existing dwelling, complete with a basement that extends from the footprint of the new building across the current rear garden area. At the southern end of the basement, a second above ground building/structure will be constructed to provide further accommodation. As such, the basement will extend across circa 50% of the site area, leaving only the front drive and a section of rear garden adjoining an off-site golf course as in-situ soft landscaping. Figures 2 and 3 illustrate the proposed development scheme. Figure 2: Proposed Site Plan Figure 3: Proposed Basement Plan Site Layout A site walkover was undertaken by a qualified consultant from Lustre on 15th June 2020. A representative of the client was present throughout the site walkover. Access was not granted to the residential building present on site; only the external areas were assessed. Figure 4: Aerial Photograph The site is accessed via High Road which forms the north-western site boundary. A U-shaped driveway is present at the front of the site with a small grassed area. Evidence of a row of former trees was noted immediately adjacent to the north-western in the form of cut down tree stumps. An existing mature tree is present in the north-western corner of the site adjoining 152 High Road. It is understood from the Client that this tree has a TPO. The driveway is laid to block paving and slopes up from the road (39.66m AOD) to the single detached dwelling (41.44m AOD). The detached dwelling was orientated north-east/ south-west and extended across the full width of the site. A double garage was present in the northern part of the building. To the rear of the building a long private garden (laid to lawn) was present. Within the garden a small patio area was noted near the dwelling with a small swimming pool and flower beds. Further up the garden an ornamental pond was present with a small area of wooden decking and a shed. In this area a heating oil tank was noted, which was of modern plastic construction with internal bunding. No evidence of spills or leaks were noted. It is assumed that the heating oil tank heats water for use within the swimming pool. Ground elevation increased from the dwelling adjacent the rear wall of the house at 41.5m AOD to the rear of the garden at 45.15m AOD. Heating oil tank – modern plastic construction Small swimming pool View off-site: 152 High Road with grass over a View off-site: Golf Course to south-east basement in foreground Off-site to the east and south was a golf course. A disused and blocked drainage ditch formed the boundary between the subject site and the golf course. Several mature trees were present circa 20-30m east of the site within the golf course, and a semi-mature tree was noted on the north-eastern boundary close to the on-site pond. Tree species are not known. Site History The site history has been assessed by reviewing historical Ordnance Survey maps provided by Landmark and aerial photographic imagery from Google Earth. Relevant maps are enclosed. The historical development of the site and the surrounding area are summarised in the following tables. Date Feature Date Feature On Site Land Use Present Removed Open undeveloped space. Likely a garden associated with the residential dwelling Broom Hill 1872 1983 off-site to the north-east Southern and eastern part of the site separated by 1920 1964 fencing Current dwelling present on site. Aerial photograph 1964 - dated 1999 shows swimming pool as present. The approximate bearing of identified features is abbreviated with the first letter (e.g. south-west = SW). Approximate distances are interpreted from historical mapping and in metres. Environmentally pertinent historical information from the immediate surrounding area (within 250m) has been summarised in the following table. Date Date Distance / Surrounding Land Use Feature Feature Bearing Present Absent Residential Properties 0m, NE and SW 1964 Present Golf Course 0m, E and S 1964 Present Nursery Gardens 100m NW 1972 Present The approximate bearing of identified features is abbreviated with the first letter (e.g. south-west = SW). Approximate distances are interpreted from historical mapping and in metres. A review of planning records held by Epping Forest District Council has revealed that the current building on the subject site was granted planning permission in 1959 (ref: CHI/0064/59). Geology The 1:50,000 British Geological Survey (BGS) map (Sheet 257)1 and the BGS website (National Geoscience Information Service)2 show the site to be directly underlain by bedrock geology of the London Clay Formation comprising poorly laminated, blue-grey or grey-brown, silty to very silty clay. No superficial deposits are anticipated on site. A narrow deposit of superficial Alluvium is shown circa 75m south associated with a former stream within the grounds of the off-site golf course. It is understood that the watercourse is now culverted. Periods of construction and demolition are not noted within mapping records and therefore a significant thickness of Made Ground is not anticipated on site. Reworked natural soils are likely present. Historical borehole records have been identified relating to boreholes drilled within the general vicinity of the site and surrounding area. The closest historical borehole was recorded approximately 400m south- west of the site (TQ49SW333). A summary of ground conditions encountered is provided below. • Made Ground to 0.6m bgl, • Soft to firm greyish brown silty CLAY with some gravel to 1.7m bgl over firm yellowish brown silty sandy CLAY and GRAVEL to 2.1m bgl (superficial deposits), • Stiff and very stiff silty CLAY of the London Clay Formation proved to 10m bgl. • No groundwater was encountered during drilling. It is noted that the above borehole log is located within an area of mapped superficial deposits of the Boyn Hill Gravel Member (a sand and gravel deposit). As noted above, no superficial deposits are anticipated on the subject site. Information on ground conditions has also been obtained from the limited Phase 2 site investigation undertaken at the adjacent property, 152 High Road. The investigation was undertaken through a former tennis court as this was an area of suspected Made Ground. The exploratory holes proved between 0.62m to 1.1m of Made Ground, which comprised a light brown, slightly sandy gravelly clay. The Made Ground 1 BGS Solid and Drift Map Sheet 257 2 Information from BGS website: www.bgs.ac.uk consulted in month of report issue was noted to contain fine angular brick fragments, ash, glass fragments and coal fragments. The Made Ground was limited to the area of the former tennis court. Underlying the Made Ground, natural soils of the London Clay Formation were recorded which were described as a light orange brown mottled grey brown, slightly silty CLAY. No visual or olfactory evidence of contamination was noted in the investigation and no groundwater strikes or seepages were recorded. All boreholes were dry on completion of drilling. Hydrogeology The Groundwater Vulnerability Map of England and the Environment Agency website3 have been reviewed to determine the aquifer designations. The London Clay Formation is listed as being an unproductive stratum. These are low permeability strata which are not considered to retain significant quantities of groundwater. If groundwater is present within unproductive strata, for example within more permeable lenses or small fissures, it is typically discontinuous, of low value and very low sensitivity. The Environment Agency has defined Source Protection Zones (SPZs) for groundwater sources used for public drinking water supply. These zones show the risk of contamination from any activities that might cause pollution in the area. The maps show three main zones (inner, outer and total catchment) and a fourth zone of special interest. No groundwater Source Protection Zones have been identified within 1km of the subject site. No groundwater abstractions are recorded within 1km of the site. A single discharge consent is listed within 1km from the subject site located 110m west and held by Mr. R.A. Warner & Mr. J.S. Lloyd. The now transferred consent relates to the discharge of sewage (final/treated effluent) to land/soakaway under license no.