Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Presented to Consortium of Taylor Wimpey, Persimmon Homes and Hopkins Homes Issued: October 2017 Delta-Simons Project No. 17-0337.02
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
Report Details
Client Consortium of Taylor Wimpey, Persimmon Homes and Hopkins Homes
Report Title Preliminary Phase II Geo-Environmental Assessment
Phase 2 – GT20 (Parcels R1-R4), Land off Salhouse Road, Sprowston, Norwich, Site Address NR13 6LB
Project No. 17-0337.02
Report Date October 2017
Delta-Simons Tom Horner ([email protected]) Contact
Quality Assurance
Issue Issue Technical Status Comments Author Authorised No. Date Review
1 Final 20.10.2017 - Gemma Tatton Tom Horner Dan Webb Consultant Principal Unit Manager
About us
Delta-Simons is a trusted, multidisciplinary environmental consultancy, focused on delivering the best possible project outcomes for customers. Specialising in Environment, Health & Safety and Sustainability, Delta-Simons provide support and advice within the property development, asset management, corporate and industrial markets. Operating from eight locations - Lincoln, London, Leeds, Manchester, Norwich, Nottingham, Durham and Dublin - we employ over 70 environmental professionals, bringing experience from across the private consultancy and public sector markets. Delta-Simons is proud to be a founder member of the Inogen® Environmental Alliance, enabling us to efficiently deliver customer projects worldwide by calling upon over 4,330 resources in our global network of consultants, each committed to providing superior EH&S and sustainability consulting expertise to our customers. Inogen Environmental Alliance offers its clients more consultants, with more services in more countries than the traditional multinational consultancy.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
Executive Summary
Brief Delta-Simons Environmental Consultants Limited (‘Delta-Simons’) was instructed by Taylor Wimpey, Persimmon Homes and Hopkins Homes to undertake a Phase II Geo- Environmental Assessment for a parcel of land known as ‘GT20’ (Parcels R1-R4), located off Salhouse Road, Sprowston, Norwich, NR13 6LB (hereafter referred to as the ‘Site’). It is understood that the Site is to be redeveloped for residential use, comprising approximately 460 dwellings, however, at the time of writing, a specific proposed development plan had not been provided to Delta-Simons. The purpose of this assessment is to identify the potential for land contamination issues to be present at the Site in the context of the proposed development, to support the planning application and to provide a geotechnical assessment.
Site Setting The Site was historically occupied by agricultural land, with areas of woodland, Round Hill Plantation and Arnup’s Belt, present in the northern and southern areas of the Site respectively. A Polo Ground was also present in the south of the Site from 1919 to circa 1929. The Site is currently utilised for agricultural purposes.
Ground The current ground investigation recorded Topsoil underlain by the Sherringham Cliffs Conditions Formation. In the north of the Site, the superficial Happisburgh Glacigenic Formation has been identified overlying the Sherringham Cliffs Formation. Both the Happisburgh Glacigenic Formation and the Sherringham Cliffs Formation comprised alternating layers of cohesive and granular deposits to a maximum proven depth of 10.45 m bgl.
Land Human Health Contamination No elevated concentrations of contaminants have been identified compared to their Assessment respective GAC in the context of a residential (with consumption of home grown produce) end use. Controlled Waters Although elevated concentrations of heavy metals including cadmium, chromium, mercury and nickel have been identified within the groundwater across the Site, these are considered to be representative of background concentrations, and therefore, do not pose a significant risk to sensitive receptors. Built Environment Although no significant organic contamination has been identified at the Site, confirmation should be sought from the Local Water Authority as to whether they will require upgraded water supply pipework. Ground Gas Ground gas monitoring data indicates that the Site should be classified as CS2 – Amber 1. This scenario will require the implementation of ground gas protection measures within the proposed development, however, given that elevated concentrations of carbon dioxide and flow rates were only recorded in the south of the Site, it may be possible to ‘zone’ the Site once final development layouts are known and following consultation with the Local Authority.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
Geotechnical Shallow strip foundations are considered to be suitable for the proposed development, Assessment founded within the underlying superficial deposits, at a minimum depth of 1.00 m - 1.50 m bgl. Suspended floor slabs are likely to be a requirement to meet ground gas protection guidance in line with the Site’s CS2 – Amber 1 classification, in the south of the Site. It is recommended that a conservative CBR value of 2% should be adopted for the shallow soils, for preliminary pavement design for external areas. It is recommended that plate CBR tests are undertaken at formation level prior to finalising pavement design. Buried concrete may be designed in accordance with DS-2 and AC-2, as per requirements of BRE Special Digest 1:2005 ‘Concrete in aggressive ground’..
Recommendations Based on the findings of this report, the following recommendations are made: ▲ In order to fully characterise the gas regime at the Site, it is recommended that additional ground gas monitoring is undertaken once development layouts have been finalised; ▲ Waste classification has not been undertaken as part of the scope of works, should it be proposed to dispose of materials from the Site, then specific additional investigations may be needed to classify the materials in accordance with current regulatory requirements; ▲ Any topsoil imported onto the Site as part of the development works, or sourced from the Site and re-used, should be tested to confirm suitability, prior to, and once placed, in landscaped / garden areas; ▲ Additional, unidentified localised areas of contamination may exist at the Site and an appropriate ‘hotspot’ protocol should be in place for groundworkers to act upon should such contamination be identified during the construction process; ▲ As with all development sites, groundworkers who are required to perform sub- surface work at the Site should be made aware of the known contaminants in soil and groundwater and the possibility of encountering additional localised low levels of contamination. Therefore, good standards of personal hygiene should be observed and appropriate levels of PPE utilised where necessary; ▲ Suitable dust suppression techniques will need to be implemented by the groundworkers during construction works; and ▲ Confirmation should be sought from the Local Water Authority as to whether they will require upgraded pipework to be installed for new service installations.
This is intended as a summary only. Further detail and the limitations of the assessment are provided within the main body of the Report.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
Table of Contents
1.0 INTRODUCTION ...... 1 1.1 Appointment ...... 1 1.2 Context & Purpose ...... 1 1.3 Scope of Works ...... 1 1.4 Existing Information ...... 1 1.5 Limitations ...... 1 2.0 SITE DETAILS ...... 2 2.1 Site Setting ...... 2 2.2 Preliminary Conceptual Site Model ...... 3 3.0 SITE INVESTIGATION ...... 5 3.1 Intrusive Investigation ...... 5 3.1.1 Health & Safety Considerations ...... 5 3.2 Scope of Ground Investigation and Rationale ...... 5 3.2.1 Scope ...... 5 3.2.2 Rationale ...... 5 3.3 Ground Investigation Factual Data ...... 5 3.4 In-Situ Testing and Sampling ...... 5 3.5 Geotechnical Laboratory Testing...... 6 3.6 Environmental Sampling, In-Situ Testing and Laboratory Analysis ...... 6 3.7 Monitoring Programme ...... 7 4.0 GROUND SUMMARY ...... 8 4.1 Introduction ...... 8 4.2 Ground Model ...... 8 4.3 Groundwater ...... 8 4.3.1 Strikes During Investigations ...... 8 4.3.2 Levels During Monitoring Programme ...... 9 4.4 Material Properties ...... 9 4.5 Geochemical Testing ...... 10 4.6 Ground Gas Data...... 10 4.7 Visual and Olfactory Evidence of Contamination ...... 10 5.0 GEOTECHNICAL ASSESSMENT ...... 11 5.1 Summary of Development Proposals ...... 11 5.2 Foundations ...... 11 5.2.1 Spread Foundations ...... 11 5.2.2 Volume Change Potential ...... 12 5.2.3 Ground Improvement Techniques ...... 12 5.2.4 Piling ...... 12 5.2.5 Floor Slabs ...... 12 5.3 Roads and Pavements ...... 12 5.4 Drainage and Soakage Tests ...... 13 5.5 Excavations & Obstructions ...... 13 5.6 Groundwater ...... 13 5.7 Slopes & Retaining Features ...... 13 5.8 Earthworks ...... 13 5.9 Chemical Attack on Buried Concrete ...... 13 6.0 GENERIC QUANTITATIVE RISK ASSESSMENT ...... 14 6.1 Introduction ...... 14 6.2 Human Health GQRA ...... 14 6.2.1 Risks from Soil Sources ...... 14 6.2.2 Risks from Groundwater Sources ...... 16 6.2.3 Risks from Non-Aqueous Phase Liquids (NAPL) ...... 16 6.3 Controlled Waters/Water Environment GQRA ...... 16 6.3.1 Groundwater Results ...... 16 6.3.2 Light Non Aqueous Phase Liquid (LNAPL) ...... 18 6.4 Built Environment...... 18
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02
6.4.1 Potable Water Supply Pipes ...... 18 6.4.2 Building Materials ...... 18 6.5 Waste Classification ...... 18 7.0 BULK GROUND GAS RISK ASSESSMENT ...... 19 7.1 Ground Gas Conceptual Site Model ...... 19 7.1.1 Sources ...... 19 7.1.2 Receptors ...... 19 7.1.3 Pathways ...... 19 7.2 Duration & Extent of Monitoring ...... 19 7.3 Ground Gas Risk Assessment ...... 20 7.3.1 Background ...... 20 7.3.2 Gas Screening Value (GSV) ...... 20 7.4 Ground Gas Risk Mitigation ...... 20 7.5 Radon ...... 21 7.6 Organic Vapours ...... 21 8.0 REVISED CONCEPTUAL SITE MODEL ...... 22 9.0 CONCLUSIONS & RECOMMENDATIONS ...... 24 9.1 Geotechnical Summary ...... 24 9.2 Contamination Issues ...... 24 9.2.1 Human Health ...... 24 9.2.2 Controlled Waters ...... 24 9.3 Recommendations for Supplementary Work ...... 24
Figures Figure 1 Site Location Map Figure 2 Exploratory Hole Location Plan Figure 3 Corrected SPT, Depth and Strata Type
Appendices Appendix A Limitations Appendix B Risk Definitions Appendix C BACTEC Explosive Ordnance Desktop Threat Assessment Appendix D Borehole Logs and SPT Calibration Certificate Appendix E Geotechnical Analysis Results Appendix F Soil Chemical Analysis Results Appendix G Groundwater Chemical Analysis Results Appendix H Field Monitoring Data/Gas Monitoring Data
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 1
1.0 Introduction
1.1 Appointment Delta-Simons Environmental Consultants Limited (“Delta-Simons”) was instructed by a consortium of Taylor Wimpey, Persimmon Homes and Hopkins Homes (the “Client”) to prepare a Phase II Geo-Environmental Assessment for a parcel of land known as ‘GT20’ (Parcels R1-R4), located off Salhouse Road, Sprowston, Norwich, NR13 6LB (the “Site”).
1.2 Context & Purpose The aim of the investigation is to complete a preliminary geo-environmental assessment of the proposed development area, specifically to target areas of the Site which might represent an elevated geo-environmental risk in respect of the proposed development of the Site. The investigation will obtain information regarding ground conditions, from which risks to end-users, the environment and structures can be assessed, with mitigation measures outlined, if necessary.
The investigation will provide geotechnical information in order to comment on the preliminary design of foundations and infrastructure. The report will provide recommendations for further work based on the findings of the investigation, if required.
It is understood that the Site is to be redeveloped for residential use, however, at the time of writing, a specific proposed development plan had not been provided to Delta-Simons.
1.3 Scope of Works The scope of the investigation and layout of this report has been designed with consideration of CLR11 (Environment Agency, 2004a) and BS 10175: 2013 Investigation of Potentially Contaminated Sites – Code of Practice (BSI, 2011) and guidance on land contamination reports issued by the Environment Agency (EA) (2010a).
The project was carried out to an agreed brief as set out in Delta-Simons’ proposal dated 6th July 2017 (ref. 17- 0337.02/DRW/TCH/06072017). The scope of works is outlined in Section 3.2.1.
1.4 Existing Information The Phase II Geo-Environmental Assessment was undertaken following completion of Delta-Simons’ Preliminary Geo-Environmental Risk Assessment, GT20, Parcels R1-R4, Land at White House Farm, Sprowston, Norwich, (ref. 17-0337.01), dated June 2017.
1.5 Limitations The assessment is limited to the issues agreed within the proposal for the works. Notes on limitations associated with this assessment are provided in Appendix A. In addition, no specific development plans have been made available for the proposed redevelopment, therefore, an assumption has been made that the majority of the Site will comprise residential properties with associated gardens and roadway infrastructure, which represents the most sensitive end-use for the Site, from a contaminated land perspective.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 2
2.0 Site Details
2.1 Site Setting A summary of the current Site status, environmental setting and key historical features is presented below. This has been summarised from the existing report(s) listed in Section 1.4 which should be consulted for further detail.
Co-ordinates Centred approximately at National Grid Reference Elevation 22 to 34 m AOD 626210, 311950. Area 25 Ha
Site Location The Site is located on the outskirts of Sprowston, off Salhouse Road, approximately 1.8 km east of Sprowston town centre. A Site Location Map is provided as Figure 1. The surrounding area predominantly comprises residential and agricultural land use, with Sprowston Manor Golf Course located adjacent to the north of the Site. White House Farm is located to the east of the Site.
Current Site Use The Site is predominantly occupied by arable farm land with an area of woodland, associated with Round Hill Plantation, present in the southern area of the Site and a small belt of woodland, known as Arnup’s Belt, present in the north of the Site. Laundry Lane crosses through the centre of the Site, providing access to White House Farm from Blue Boar Lane. The Site is predominantly flat, although the areas of woodland in the south and north of the Site are at a higher elevation compared to the remainder of the Site.
Proposed It is understood that the Site is to be redeveloped for residential use, comprising Development approximately 460 dwellings, however, at the time of writing, a specific proposed development plan had not been provided to Delta-Simons. Identified human and built environment receptors (R) relevant to the proposed development comprise: ▲ R1 - Construction workers. ▲ R2 - Third parties during construction (adjacent Site users and adjacent residents). ▲ R3 - Future Site users and maintenance workers. ▲ R4 - The Built Environment (new buildings and infrastructure / utilities). ▲ R5 – Plants in landscaped / garden areas.
Environmental From the British Geological Survey online viewer, the Site is indicated as being Setting underlain by superficial deposits of Glacial Till (Happisburgh Glacigenic Formation) in the north, but otherwise over the Sherringham Cliffs Formation (Sand & Gravel), followed by solid geology comprising the Crag Group (Sand & Gravel) and the Lewes Nodular Chalk. The Envirocheck® Report indicates that the nearest surface water feature is a drain located in the north-east of the Site. Additional water features have also been identified on-Site including a series of balancing ponds in the northern area of the Site, as well as two drains and a pond located within the area of Round Hill Plantation in the south of the Site. The following controlled water / environmental receptors have been identified: ▲ R5 - The drains and ponds located in the north and south of the Site. ▲ R6 - The underlying Secondary A Aquifer and Principal Aquifer at depth.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 3
Key Historical From the earliest available mapping of 1885, the Site appears to have been in Features agricultural use, with an area of woodland, later labelled as Round Hill Plantation, in the southern area of the Site. White House Farm was shown to the east of the Site until present day. By 1908, the northern area of the Site formed part of Sprowston Hall estate until circa 1957 and an area of woodland, labelled as Arnup’s Belt, was shown in the northern area of the Site to present day. By 1919, the southern area of the Site was shown to form part of a Polo Ground but was no longer labelled by 1929. The Site remained in agricultural use to present day, with associated drains, tracks and cattle grids shown on Site between 1971 and 2000. Google Earth aerial photography shows there to be a series of empty balancing ponds in the northern area of the Site which appear to have been constructed at some time between 2013 and present day. It is known that these are associated with a new residential development to the south of the northern-most area of the Site. No potential sources of contamination have been identified on-Site based on the review of historical mapping. Potential sources of contamination within 250 m of the Site include: ▲ A pond located approximately 20 m east of the southern area of the Site from 1882 but no longer shown by 1989 (presumably infilled); ▲ A pond located adjacent to the southern area of the Site from 1928 but no longer shown by 1989 (presumably infilled); and ▲ An electrical sub-station associated with Sprowston Manor Hotel, shown approximately 220 m north of the Site from 1994 until present day, however, this is considered unlikely to represent a risk given that the use of Polychlorinated Biphenyls (PCBs) within such structures was outlawed by the time it was first shown to be present, and is, therefore, not considered further in this Assessment. The ponds off-Site are not considered to pose a significant risk to the Site, given the period of time elapsed since being potentially infilled, any ground gas generation is likely to have ceased. Furthermore, given their relatively small size, these are not considered likely to represent a significant source of ground gas capable of impacting the proposed development on-Site.
Summary of As part of the Preliminary Geo-Environmental Risk Assessment, a Landmark Previous Reports Envirocheck® Report pertaining to the Site was reviewed. The Envirocheck® Report listed a BGS Recorded Mineral Site, located approximately 10 m south-east of the Site, relating to Sprowston Grange Pit (ceased). The Contaminated Land Officer (CLO) at Broadland District Council was contacted by Delta-Simons and noted that there were some small areas of potentially infilled land located on-Site which were considered unlikely to pose a significant risk to current land use, however, if the Site was to be considered for residential use, they may need to be considered further. Delta-Simons was provided with a plan highlighting the locations of the areas of potentially infilled land. The plan showed a small area in the south of the Site, which corresponded to the location of a pond shown adjacent to the Site on historical mapping between 1928 and 1989. As noted in the section above, this is not considered to represent a potential source of contamination, given the period of time elapsed since being potentially infilled. The agricultural use of the Site and the off-Site BGS Recorded Mineral Site were considered to represent potential sources of contamination.
2.2 Preliminary Conceptual Site Model A summary of the preliminary Conceptual Site Model is presented below.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 4
Source(s) Potential Contaminants of Pathway(s) Receptor(s) Preliminary Risk Rating Concern (CoC)
Pesticides, herbicides and localised P1, P2, P3, P4, P5, P6 R1, R2, R3, R4, R5, R6 Low Risk S1 Agricultural use of the Site hydrocarbon contamination
S2 BGS Recorded Mineral Site Hazardous ground gases P1 R1, R2, R3 Low to Moderate Risk
Pathways: ▲ P1 - Direct contact, ingestion or inhalation of soil bound contaminants / dust during or following redevelopment. ▲ P2 - Inhalation of organic vapours associated with contamination. ▲ P3 - Migration of ground gas / vapours into on-site buildings causing asphyxiation or risk of explosion. ▲ P4 - Leaching of contamination into groundwater followed by migration of groundwater to the wider groundwater environment or discharge to surface waters. ▲ P5 - Direct contact between aggressive ground conditions and new infrastructure. ▲ P6 – Root uptake.
Risk ratings are based on the classifications given in Appendix B.
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3.0 Site Investigation
3.1 Intrusive Investigation Delta-Simons carried out intrusive investigation work from 4th to 6th September 2017 to assess the potential linkages identified in the outline conceptual model (see Section 2.2 above) and to provide geotechnical information.
3.1.1 Health & Safety Considerations Service plans for the Site were provided by the Client; and a utilities clearance specialist attended the Site on 24th August 2017 to trace services on and around the Site prior to excavation of exploratory hole locations.
An initial assessment of the Site identified a potential risk in relation to Unexploded Ordnance (UXO) and so a specific UXO study was obtained from BACTEC. The Explosive Ordnance Desktop Threat Assessment is included as Appendix C. Future Contractors should undertake their own assessment of UXO risk in relation to their specific proposed scope of works.
3.2 Scope of Ground Investigation and Rationale
3.2.1 Scope The ground investigation comprised the following items:
▲ Initial service avoidance exercise; ▲ Supervision of all works by a Delta-Simons Geo-Environmental engineer. All intrusive locations were logged in accordance to BS5930:2015 Code of Practice for Site Investigations; ▲ Drilling of three cable percussive boreholes (CP201 to CP203) to a maximum depth of 10.45 m bgl; and ▲ Excavation of six trial pits (TP201 to TP206) to a maximum depth of 3.20 m bgl. 3.2.2 Rationale
Location Rationale
CP203 To target the BGS Recorded Mineral Site, located approximately 10 m south-east of the Site
To provide general Site coverage, and to target the various geological sequences mapped CP201, CP202 and TP201 to TP206 across the Site area.
3.3 Ground Investigation Factual Data The investigation locations were surveyed in by the appointed surveying contractor to an accuracy of approximately +/- 0.1m. An intrusive exploratory hole location plan is presented as Figure 2.
Delta-Simons engineer verified borehole logs are presented as Appendix D. The SPT Calibration Certificate, in accordance with BS EN ISO 22476-3:2005 (incorporating corrigendum No. 1 2007), Geotechnical investigation and testing - Field testing - Part 3: Standard penetration test for SPT trip hammers is also provided in Appendix D.
3.4 In-Situ Testing and Sampling SPT tests were undertaken in all boreholes at 1.00 m intervals until 5.00 m bgl, then every 1.5 m bgl thereafter. The results of these tests are presented in the borehole logs included as Appendix D.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 6
Hand vane shear tests were undertaken on cohesive soils encountered within trial pits. Test results are shown on the trial pit logs presented in Appendix D.
Sampling comprised disturbed tub, jar and bulk bag samples as detailed on the borehole logs.
3.5 Geotechnical Laboratory Testing A selection of soil samples were submitted to the UKAS accredited laboratory for a range of geotechnical testing, the results of which are included in Appendix E.
The programme of geotechnical testing undertaken on samples obtained from the natural soils is presented within the table below. The purpose of the laboratory testing was to assess the classification properties of the soils encountered in order to inform the outline geotechnical design advice.
Analysis No. Tested Rationale
Moisture content 3 To enable geotechnical assessment of cohesive soils
Atterberg Limits 3 To enable geotechnical assessment of cohesive soils
Particle size distribution 3 To enable geotechnical assessment of granular soils
3.6 Environmental Sampling, In-Situ Testing and Laboratory Analysis Soils collected for laboratory analysis were placed in a variety of containers appropriate to the anticipated testing suite. Samples were stored in accordance with Delta-Simons’ quality procedures to maintain sample integrity and preservation and to minimise the chance of cross contamination. Records of the samples taken as part of the site investigation works, including their depths and location, are included within the exploratory hole records in Appendix D.
One groundwater sample was collected from each of the three boreholes on 13th September 2017. The groundwater samples were collected using a dedicated disposable bailer.
Samples analysed for environmental purposes were placed in chilled cool boxes on-Site and transported to the laboratory for analysis on completion of the Site investigation works / groundwater sampling visit.
The rationale for chemical analysis is presented in the table below and the results of the chemical laboratory testing are included in Appendix F and G.
No. of Samples Tested Analytes Rationale Soil Ground- water
Analysed shallow topsoil samples selected for chemical Asbestos 10 - analysis as is common to many sites.
Potential contaminants of concern, common to many sites, Heavy metals 10 3 both naturally occurring and anthropogenic.
Hexavalent chromium 10 - Potential contaminant of concern, common to many sites.
Targeting the Site in relation to petroleum type sources as Total Petroleum Hydrocarbons 8 - identified in the preliminary CSM.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 7
No. of Samples Tested Analytes Rationale Soil Ground- water
Criteria Working Group Method (TPHCWG), Targeting the Site in relation to petroleum type sources as 10 3 speciated Polycyclic Aromatic Hydrocarbons identified in the preliminary CSM.
To assess potential for chemical attack on buried pH, sulphate 10 3 concrete.
To assess the impact of current and historical agricultural Combined Organochlorine and activities on the Site. Note that pesticides are associated 3 - Organophosphorus Pesticides (OCOPP) with arable farming which currently occurs on-Site and may have occurred historically.
3.7 Monitoring Programme
Four rounds of groundwater level and ground gas monitoring were undertaken on the newly installed wells (CP201, CP202 and CP203) between 13th September and 4th October 2017. Measurements of the depth to groundwater within the monitoring wells were taken using an electronic dip meter. The groundwater level monitoring sheets are included as Appendix H.
To characterise the ground gas regime at the site, an infrared gas meter was used to measure gas flow, concentrations of carbon dioxide (CO2), methane (CH4) and oxygen (O2) in percentage by volume. Initial and steady state concentrations were recorded. The atmospheric pressure before and during monitoring, together with the weather conditions, was recorded. All monitoring results obtained to date together with the temporal conditions are contained within Appendix H.
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4.0 Ground Summary
4.1 Introduction The sections below summarise the ground and groundwater conditions encountered during the Site investigation.
4.2 Ground Model A summary of the observed ground conditions at the Site is provided below.
Summary of Observed Ground Conditions
Depth Range Maximum Strata Typical Strata Description of Strata Proven Comments Base (m) Thickness (m)
Topsoil was encountered in all locations A fragment of ceramic was and typically comprised dark brown Topsoil 0.30 to 0.45 0.45 encountered within the slightly sandy slightly gravelly silt, with topsoil in CP201. gravel comprising flint.
Granular deposits identified Granular superficial deposits were were associated with both encountered in all locations and Superficial Deposits the Sherringham Cliffs predominantly comprised medium-dense 0.30 to 10.45 10.15 Formation and the (granular) orangish brown SAND and or GRAVEL, Happisburgh Glacigenic with varying proportions of clay and silt. Formation.
CP201: 3.10 to 3.40 and 9.80 to 10.00 Cohesive deposits identified Cohesive superficial deposits were were associated with both encountered in CP201, CP202, CP203 CP202: 1.30 Superficial Deposits the Sherringham Cliffs and TP205 and predominantly comprised tp 3.00 2.00 Formation and the (cohesive) orangish brown slightly sandy CLAY with CP203: 10.00 Happisburgh Glacigenic occasional flint gravel. to 10.45 Formation. TP205: 1.00 to 3.00
Bedrock is not considered to have been encountered.
4.3 Groundwater
4.3.1 Strikes During Investigations Groundwater strikes recorded as excavation progressed during the Site investigation ranged from 6.00 to 7.50 m bgl. Groundwater was also encountered at 3.00 m bgl in TP205. The groundwater strikes during drilling are summarised below.
Environment | Health & Safety | Sustainability Preliminary Phase II Geo-Environmental Assessment Phase 2 – ‘GT20’ (Parcels R1-R4) Delta-Simons Project Number 17-0337.02 Page 9
Exploratory Hole Water strike Stratum Comment during drilling (m bgl)
CP201 7.50 Happisburgh Medium inflow Glacigenic Formation
CP202 6.00 Happisburgh Slow inflow Glacigenic Formation
4.3.2 Levels During Monitoring Programme Groundwater levels were monitored on a total of four occasions between 13th September and 4th October 2017. Monitoring data and LNAPL measurements are provided in Appendix H and summarised in the table below.
Exploratory Response Zone Water level during LNAPL during Stratum Hole monitoring (m bgl) monitoring (mm)
(m bgl) Min Max. Min Max.
CP201 1 – 10 7.92 7.97 0 0 Happisburgh Glacigenic Formation
CP202 1 – 10 5.02 5.04 0 0 Happisburgh Glacigenic Formation
CP203 1 – 10 7.27 7.35 0 0 Happisburgh Glacigenic Formation
Groundwater levels during monitoring varied between 5.02 and 7.97 m bgl within the Happisburgh Glacigenic Formation.
4.4 Material Properties The table below summarises the factual material properties based upon the results of in-situ and laboratory test data and where appropriate provides derived geotechnical parameters.
Superficial Deposits Superficial Deposits Parameter (granular) (cohesive)
Moisture Content2 - w - 15%
Liquid Limit2 - wL - 34% - 42%
Plastic Limit2 - wP - 16% - 20%
Plasticity Index2 - IP - 18% - 24%
Uncorrected SPT N Value 6 – 50 18
Corrected1 SPT (N60) 7.5 – 62.6 22.5
1. SPT N values corrected for energy delivered to drive rods utilising the determined energy ratio (Er): N60 = (Er x N) / 60 after BS EN ISO 22476-3:2005
2. From laboratory test results
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4.5 Geochemical Testing Geochemical analysis was undertaken on samples of topsoil and underlying superficial deposits, tested for selective contaminants (BRE Special Digest 1:2005 (3rd Edition), Concrete in Aggressive Ground, the results of which are summarised in the table below.
Tests No. of Tests Minimum Maximum
Soil - pH 10 7.1 7.9
Soil - Water Soluble Sulphate 10 <10 mg/L <10 mg/L
Water – pH 3 6.9 7.1
Water - Sulphate 3 27 mg/L 560 mg/L
4.6 Ground Gas Data Gas monitoring results are presented in Appendix H and are summarised in the table below, a total of four rounds of gas monitoring was undertaken over a period of four weeks.
Barometric pressures ranged from 992 mB (visit 1) to 1016 mB (visit 3).
Exploratory Steady Gas Concentration (%v/v) Steady Response Zone Hole Flow Rate (m bgl) (l/hr) Carbon Methane Oxygen Dioxide Stratum Flooded?
Min Max Min Max Min Max Min Max From To
CP201 <0.1 <0.1 <0.1 4.1 15.8 20.6 <0.1 0.4 1 10 Superficial N Deposits
CP202 <0.1 <0.1 <0.1 3.1 17.1 20.8 <0.1 0.3 1 10 Superficial N Deposits
CP203 <0.1 <0.1 2.5 4.4 14.4 15.4 <0.1 2.8 1 10 Superficial N Deposits
4.7 Visual and Olfactory Evidence of Contamination No visual or olfactory evidence of potential gross contamination was observed during the investigation.
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5.0 Geotechnical Assessment
5.1 Summary of Development Proposals It is understood that the Site is to be redeveloped for residential use, comprising approximately 460 houses, however, a specific proposed development plan has not been viewed by Delta-Simons.
At the time of writing, structural and floor loadings and final levels were unknown. Consequently, the information provided below should be treated as preliminary and will be subject to review and further plot specific investigation once a scheme and levels have been finalised.
5.2 Foundations
5.2.1 Spread Foundations The topsoil (and Made Ground should it be found to be present) is considered to be too unpredictable, variable, weak and compressible in its existing condition for conventional shallow foundations at the Site.
Traditional shallow spread foundations formed into the natural Sherringham Cliffs Formation or Happisburgh Glacigenic Formation are considered likely to be suitable for the proposed residential scheme. The ground conditions revealed by the investigations have generally shown variable density (typically ranging from medium dense to very dense) coarse soils to dominate across the Site, although these are occasionally interspersed with bands of fine soils (clays / silts) and / or deeper thicker clay deposits (e.g. location TP205). It will be important that foundations are founded on a consistent medium to avoid issues of differential settlement and that the depth and presence of any fine / coarse material are understood following plot specific investigation and cognisance of proposed formation level prior to final design. Reference to Figure 3 - Corrected SPT, Depth and Strata Type, indicates a minimum design SPT of 10 to be appropriate for granular soils corresponding to an internal angle of friction of ~30 degrees (SPT N-Value and angle of shearing resistance after Peck, Hanson & Thornburn (1963). Where fine soils were encountered, consistencies ranged from firm to stiff corresponding to a minimum shear strength of ~40 kPa.
For preliminary design, the table below shows a number of typical pad and strip foundation sizes and associated allowable bearing capacities that may be assumed, based on the ground conditions proven through this investigation and soil strengths / consistencies assumed above with settlements restricted to <25 mm.
Footing Dimensions Founding Strata Allowable Bearing Capacity Maximum Load
(kN/m2) (kN)
Medium-dense sand ≥ 1.50 m 1.00 x 1.00 m pad 200 200 bgl
2.00 x 2.00 m pad Medium-dense sand ≥ 1.50 m 115 460 bgl
0.50 m wide strip Medium-dense sand ≥ 1.50 m 165 80 kN/m run bgl
1.00 m wide strip Medium-dense sand ≥ 1.50 m 110 110 kN/m run bgl
1.00 x 1.00 m pad Firm clay ≥ 1.00 m bgl 110 110
2.00 x 2.00 m pad Firm clay ≥ 1.00 m bgl 110 440
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0.50 x 8.00 m strip Firm clay ≥ 1.00 m bgl 100 50 kN/m run
1.00 x 8.00 m strip Firm clay ≥ 1.00 m bgl 100 100 kN/m run
All foundation excavations should be inspected by a suitably qualified geotechnical engineer prior to casting to ensure the appropriate depth, founding medium and strength characteristics have been achieved. Consideration should be given to differential settlements likely to result from founding differing ground conditions.
Given that SPTs commenced at 1.5m within the Cable Percussion boreholes, this is the depth from which the current investigation has strength data for the underlying granular deposits, and resultingly, is reflected in the recommended depth for foundations in these deposits. It is considered likely, however, that the recommended founding depth may be shallower following additional plot specific intrusive works which may consider assessment of shallower soils / foundation depths.
5.2.2 Volume Change Potential The volume change potential should be considered in any foundation schedule for structures and services located within the influence zone of trees or bushes (proposed, existing or to be removed) and appropriate precautions and / or founding depths should be designed accordingly. In cohesive soils, foundations will therefore need to be designed in accordance with current NHBC Standard Chapter 4.2 ‘Building Near Trees’ (2017).
The liquid limit and plasticity index results suggest that the cohesive superficial deposits have a potential swell classification of low to medium and therefore, some volume change potential is inherent within shallow cohesive deposits.
5.2.3 Ground Improvement Techniques It is not considered that ground improvement techniques would be required at the Site.
5.2.4 Piling It is not considered that a piled foundation solution would be required for the proposed residential development.
5.2.5 Floor Slabs It is likely that a suspended floor slab will be required to meet ground gas protection guidance in line with the Site’s CS2 – Amber 1 classification, in the south of the Site where elevated ground gas concentrations have been identified.
In the remainder of the Site, ground bearing slabs are likely to be suitable. All topsoil and soft soils should be removed and the formation thoroughly proof rolled. Soft spots should be excavated and replaced with well- compacted granular material.
5.3 Roads and Pavements No CBR testing has been undertaken as part of this Assessment. It is therefore recommended that a conservative CBR value of 2% should be adopted for the shallow soils, for preliminary pavement design for external areas. It is recommended that plate CBR tests are undertaken at formation level prior to finalising pavement design.
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5.4 Drainage and Soakage Tests No permeability testing has been undertaken as part of this Assessment. BRE 365 should be undertaken to provide infiltration design parameters.
5.5 Excavations & Obstructions It is expected that conventional mechanical excavators will readily remove the topsoil and superficial deposits likely to be encountered in shallow excavations.
All shallow foundation or services excavations at the Site should be considered unstable, therefore, temporary support of all excavations should be considered when excavating on-Site.
5.6 Groundwater Based on this ground investigation, significant groundwater would not be anticipated during the excavations required as part of the proposed development. Should any perched groundwater be encountered, then local dewatering via well points or sump and pump should be suitable.
5.7 Slopes & Retaining Features The Site is relatively flat and level in relation to surrounding topography, therefore slopes and retaining features are not anticipated at the Site.
5.8 Earthworks At the time of writing, finished levels were unclear, however, significant earthworks are not anticipated at the Site.
5.9 Chemical Attack on Buried Concrete In accordance with the recommendations of BRE Special Digest 1, ‘Concrete in Aggressive Ground’ 2005, the conditions of the soils at the Site would therefore be classified as Design Sulphate Class DS-2 and ACEC Class AC-2 for soils and groundwater, when considering the most appropriate type of concrete to be used at the Site in order to resist chemical attack from elevated sulphate present in the soils (assuming mobile groundwater in non-pyritic soils).
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6.0 Generic Quantitative Risk Assessment
6.1 Introduction The presence of hazardous substances in or on a site is generally only of concern if an actual or potential unacceptable risk exists. Legislation and guidance on the assessment of contaminated sites, consistent with UK best practice, acknowledges the need for a tiered risk based approach. A Preliminary Risk Assessment is presented in Section 2.2. This section represents a Generic Quantitative Risk Assessment (GQRA) being a comparison of site contaminant levels against Generic Assessment Criteria.
6.2 Human Health GQRA The assessment of risks in relation to human health has been undertaken using Generic Assessment Criteria as detailed within the appropriate tables. Risks from soil, groundwater and Non-Aqueous Phase Liquids (NAPL) have been considered.
The end use scenario adopted for the assessment is a residential end use, considered appropriate based on the proposed redevelopment of the Site.
6.2.1 Risks from Soil Sources Based on the proposed use of the Site for residential use, the soil and groundwater chemical data has been compared against a residential with consumption of home grown produce end use GAC for 1% soil organic matter (SOM) content.
The laboratory results for contaminants exceeding detection limit compared to their respective GAC are presented in the table below.
The primary exposure pathways given in the table are as follows:
P1 Ingestion of soil and indoor dust and / or oral background exposure
P2 Consumption of home-grown produce and attached soil
P3 Inhalation of dust (background and indoor)
P4 Inhalation of vapour (background and indoor)
P5 Direct dermal contact
P6 Root Uptake
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Contaminant No. Max GAC GAC No. Relevant Location of Exceedances (depth) Area of Site of Samples Conc. (mg/kg) Source Exceed Pathways Exceedance (mg/kg) GAC Metals and metalloids Arsenic 10 11 37 C4SL - 1 ,2, 3, 5 Boron 10 0.53 290 LQM - 1 ,2, 3, 5 Cadmium 10 0.20 10 SGV - 1 ,2, 3, 5 Copper 10 23 2400 LQM - 1 ,2, 3, 5, 6 - - Lead 10 78 200 C4SL - 1 ,2, 3, 5, 6 Mercury 10 0.22 7.4 DS-GAC - 1 ,2, 3, 4, 5 Nickel 10 12 130 LQM - 1 ,2, 3, 5, 6 Zinc 10 590 3700 LQM - 1 ,2, 3, 5 Polyaromatic Hydrocarbons Phenanthrene 10 0.51 95 LQM - 1 ,2, 3, 5 Fluoranthene 10 1.30 280 LQM - 1 ,2, 3, 5 - - Pyrene 10 1.40 620 LQM - 1 ,2, 3, 5 Petroleum Hydrocarbons Total Petroleum Hydrocarbons 10 21 5000 DS - 1 ,2, 3, 4, 5 - -
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None of the Site-specific contaminants of concern were recorded at concentrations in excess of their respective GAC. Furthermore, no asbestos fibres or pesticide compounds were identified within the samples analysed.
The soil analysis results are considered further in the Conceptual Site Model (CSM) presented in Section 8.0 with regard to potential pollutant linkages.
6.2.2 Risks from Groundwater Sources Based on the proposed use of the Site for residential use, the soil and groundwater chemical data has been compared against a residential with consumption of home grown produce GAC to assess risks from groundwater sources to indoor air and subsequent vapour inhalation indoors.
No concentrations of volatile contaminants have been identified above the laboratory limit of detection within the groundwater samples analysed.
6.2.3 Risks from Non-Aqueous Phase Liquids (NAPL) Soil and groundwater exposure models used in generating Generic Assessment Criteria do not account for the potential for NAPL to represent a source of risk to human health, principally due to the production of vapours. Whilst it is possible to calculate theoretical soil saturation limits, in reality, due to co-solubility effects, these are not an appropriate indicator of the presence of NAPL. In order to assess the presence of NAPL, for petroleum hydrocarbons, an assessment criteria of 5000 mg/kg has been applied based on professional experience.
The following has been identified in relation to NAPL at the Site:
▲ No observations of NAPL were made within the soils observed during drilling; ▲ No concentrations of Total Petroleum Hydrocarbons in excess of 5000 mg/kg were recorded; and ▲ No NAPL was measured during groundwater monitoring works. On this basis, there is no evidence of NAPL being present on the Site.
6.3 Controlled Waters/Water Environment GQRA
6.3.1 Groundwater Results The approach adopted to assessing risks to Controlled Waters / Water Environment is based principally on considering the concentrations of contaminants identified within the groundwater samples obtained in comparison to relevant GAC.
Given the ‘prevent and limit’ approach of the Water Framework Directive (2000/60/EC) and the identified receptors, a range of Water Quality Standards (WQS) have been applied as Generic Assessment Criteria (GAC), these include the Freshwater Environmental Quality Standards (FEQS), the UK Drinking Water Quality Standards (DWQS), WHO Guidelines for Drinking Water Quality or Surface Waters Regulations which have been used as initial conservative GAC to assess whether groundwater contamination requires further assessment or discussion in terms of the risks to controlled waters.
Groundwater contaminant concentrations that exceed the applied GAC are then considered in the context of the Site’s environmental setting as to whether further qualitative or quantitative assessment is required as described in subsequent sections. Laboratory results above relevant detection limits are summarised in the table below with a comparison to the GAC applied.
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Contaminant No. Max GAC GAC No. Location of Exceedances (depth) Area of Site of Samples Conc. (ug/l) Source Exceed Exceedance (ug/l) GAC
Metals and Metalloids
Cadmium 3 0.69 0.25 EQS 2 CP201 and CP203 North and south
North, centre and Chromium III 3 21 4.7 EQS 3 CP201, CP202 and CP203 south
Copper 3 2.4 28 EQS - - -
Lead 3 1.1 7.2 EQS - - -
North, centre and Mercury 3 2.7 0.05 EQS 3 CP201, CP202 and CP203 south
Nickel 3 30 20 EQS 1 CP203 South
Selenium 3 2.1 10 DWS - - -
Zinc 3 28 125 EQS - - -
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Marginally elevated concentrations of cadmium have been identified in CP201 and CP203 in the northern and southern areas of the Site respectively. Elevated concentrations of chromium and mercury have also been identified in all three boreholes, with an elevated concentration of nickel identified in CP203 in the south of the Site. Given the lack of contamination sources on-Site, and that elevated concentrations of heavy metals were not identified within the soil samples, it is considered that these concentrations are representative of background concentrations, and therefore, do not pose a significant risk to controlled waters. In addition to this, there are no potable water abstractions located within 1 km of the Site.
The groundwater analysis results are considered further in the CSM presented in Section 8.0 with regard to potential pollutant linkages.
6.3.2 Light Non Aqueous Phase Liquid (LNAPL) No LNAPL has been identified at the Site.
6.4 Built Environment
6.4.1 Potable Water Supply Pipes The investigation requirements for the selection of potable water pipe material are set out in UKWIR Report 10/WM/03/21. Guidance for the Selection of Water Supply Pipes to be used in Brownfield Sites (UKWIR, 2010). This report has very specific and onerous investigation requirements and as such the detailed investigation of each utility route was not within the scope of this investigation.
A preliminary review of the results indicates that a relevant linkage is unlikely to exist associated with organic contaminants and therefore pollutant polyethylene (PE) and / or polyvinyl chloride (PVC) water supply pipes may be suitable for use on the development.
It should be noted that at the time of this investigation the future routes of water supply pipes had not been established, hence the investigation and sampling strategy is not likely to be considered fully compliant with UKWIR recommendations. Consequently, a targeted investigation and specific sampling / analytical strategy may be required at a later date once the route(s) of the supply pipe(s) are known. In addition, it is recommended that the relevant water supply company be contacted at an early stage to confirm its requirements for assessment, which may not necessarily be the same as those recommended by UKWIR.
6.4.2 Building Materials Risks to building materials associated with aggressive ground conditions is addressed in Section 5.9.
6.5 Waste Classification This investigation was not undertaken to classify materials in terms of waste disposal. Where waste disposal is required, then a specific and detailed investigation in accordance with Environment Agency Guidance WM3 would typically be required.
Should soils be required to be disposed of from Site, the results of the chemical analysis should be forwarded to the proposed receiving facility who will determine what criteria they will accept the waste from Site as. Further investigation in addition to specific waste acceptance criteria (WAC) analysis may be required.
Considering the nature of the materials encountered, more cost efficient and sustainable methods of removing the material should be considered prior to disposal at landfill (e.g. registering with the CL:AIRE Register of Materials) in an attempt to find a site with a requirement for import of material, or use of a Materials Management Plan (MMP).
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7.0 Bulk Ground Gas Risk Assessment
7.1 Ground Gas Conceptual Site Model
7.1.1 Sources No plausible potential sources of ground gas have been identified on-Site. However, the BGS Recorded Mineral Site, located approximately 10 m south-east of the Site is considered to represent a potential off-Site source of ground gas. The ponds located off-Site are not considered to pose a significant risk to the Site, given the period of time elapsed since being potentially infilled, any ground gas generation is likely to have ceased. Furthermore, given their relatively small size, these are not considered likely to represent a significant source of ground gas capable of impacting the proposed development.
7.1.2 Receptors The principal receptors under consideration are future residents. Other receptors include adjacent site users / residents and future maintenance / construction workers.
7.1.3 Pathways The underlying geology is likely to allow preferential migration of ground gases, given that the superficial deposits underlying the Site have predominantly been encountered as sand and / or gravel.
Based on the above, migration from the off-Site BGS Recorded Mineral Site is considered a possibility, given its proximity to the Site and the superficial deposits encountered. Furthermore, given the absence of details concerning the period of operation and subsequent infilling of the mineral site, the potential for migration of gas from this source should not be discounted at this stage.
The most significant pathways with respect to future residents relate to the potential for gases to enter future dwellings. At present, no gas protections measures are assumed. Consequently, ingress into dwellings may be possible through voids in the floor including service entry points and cracks.
Future maintenance / construction workers may come into contact with hazardous ground gases via entry into below ground confined spaces such as excavations or service entries / inspection points.
7.2 Duration & Extent of Monitoring Tables 5.5a and 5.5b within CIRIA C665 detail current recommended monitoring duration and frequency for sites in the UK. Based on the identification of potential sources in the preceding section, the gas generation potential is considered to be low to moderate, whilst the sensitivity of the proposed development is high.
Gas monitoring has been carried out at the Site during four return monitoring visits between 13th September and 5th October 2017.
During the four monitoring visits, gas concentrations above detection limits have been recorded in all three monitoring positions. The locations of the monitoring wells are highlighted on Figure 2 and indicate representative coverage across the whole study area. CP203 has been positioned close to the southern boundary of the Site, in the vicinity of the off-Site former BGS Recorded Mineral Site.
Barometric pressures during the gas monitoring period ranged from 992 mB to 1016 mB, as such, worst case conditions are considered to have been captured (<1000 mB).
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7.3 Ground Gas Risk Assessment
7.3.1 Background Based on the proposed residential end use, the following documents have been consulted when assessing the gas regime at the site:
▲ NHBC/RSK Group PLC (2007), Guidance on Evaluation of Development Proposals on Sites where Methane and Carbon Dioxide are Present, Report Edition No. 4. ▲ British Standards Institute (BSI, 2015): Code of practice for the design of protective measures for methane and carbon dioxide ground gases for new buildings, BS:8485. The presence of a source of hazardous gas within the ground does not necessarily indicate a risk will be present. Consideration of recorded gas flows together with source concentrations can allow an initial assessment to be made of the potential both for generation and subsequent migration of gas. A Characteristic Situation (CS) is derived from an assessment of the ground gas data and forms the basis of determining mitigation measures.
7.3.2 Gas Screening Value (GSV) The Gas Screening Value (gas concentration as a fraction x maximum recorded flow) is used to provide an initial assessment of risks to future site users. The GSVs calculated for the monitoring wells are presented in the following table.
Maximum GSV / Characteristic Situation Methane Maximum Carbon Maximum Flow Location Methane Carbon Dioxide (%v/v) Dioxide (%v/v) Rate (l/hr)
GSV CS GSV CS
CP201 <0.1 4.1 0.4 0.0001 CS1 0.0164 CS1
CP202 <0.1 4.0 0.3 0.0003 CS1 0.012 CS1
CP203 <0.1 4.4 2.8 0.0028 CS1 0.1232 CS2
Notes:
GSV = Gas Screening Value
In accordance with NHBC and BSI guidance, and using maximum recorded parameters and the calculated GSV’s, the proposed residential development has an Amber 1 Traffic Light Classification and has been classified as CS2 (Low Risk) respectively. This is due to the maximum carbon dioxide concentration of 4.4% v/v and maximum flow rate of 2.8 l/hr, both recorded in CP203 in the south of the Site. The remainder of the Site would be classified as CS1 / Green.
7.4 Ground Gas Risk Mitigation The ground gas regime at the Site has been classified as Amber 1 in accordance with the NHBC guidance and it is recommended that this situation is assumed for design purposes. Given that elevated carbon dioxide concentrations and flow rates were only recorded in the south of the Site, it may be possible to ‘zone’ the Site once fully approved layouts are known, with less stringent gas protection measures in those areas that have continually exhibited low ground gas levels.
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BS:8485 provides a scoring system to determine the appropriate protection measures for a proposed development in accordance with the identified ground gas regime. Table 3 of BS:8485 summarises typical UK building types, which for this development will comprise Type A (private). Table 4 details the points required for the Characteristic Situation, which for CS2 is 3.5. This can be achieved by a combination of the following:
▲ Structural barriers (Table 5) ▲ Ventilation (Table 6) ▲ Gas Membrane (Table 7) The above should be considered in conjunction with the proposed foundation / floor slab design to achieve the minimum score required within BS 8485:2015.
The above assessment relates solely to future residential occupiers. Given the nature of the ground gas regime at the Site, no further works are considered necessary to protect 3rd parties / surrounding occupiers. Entry to excavations / confined spaces should be restricted to personnel with relevant Confined Spaces training and with prior conformation of atmospheric conditions.
7.5 Radon The Site is not located within an area where radon protective measures are required.
7.6 Organic Vapours Sources of volatile vapours have not been identified on-Site, therefore, specific vapour resistant membranes are not considered to be necessary within the proposed development.
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8.0 Revised Conceptual Site Model
A revised CSM is presented in the table below, and has been formulated taking into account all of the available data from the Delta-Simons intrusive investigation, suitable for a Site with a proposed residential end-use with consumption of home grown produce.
Revised Conceptual Site Model
Source Pathways Receptors Confirmed Justification / Mitigation Risk?
Consumption of home Human health – future The risk to human health is anticipated to be very low based on the grown produce and No residents recorded contaminant concentrations. attached soil
Despite no elevated contamination concentrations being recorded Ingestion and / or Human health – No within the soils, short term risk to construction workers would be inhalation of soil / dust construction workers mitigated by use of PPE and provision of suitable welfare facilities.
Secondary A Aquifer (Sherringham Cliffs Migration of contaminants No elevated concentrations of contaminants have been identified Formation) and Principal into groundwater within the soils at the Site. The elevated heavy metals identified Detectable concentrations of heavy metals Aquifer at depth (Chalk within the groundwater are considered to be representative of No have been identified within the soils across Formation) background levels, and therefore, are not considered to pose a the Site. significant risk to controlled waters. In addition to this, there are no Migration of contaminants potable abstractions located within 1 km of the Site. Marginally elevated concentrations of heavy Drains and ponds on-Site metals have been identified in the into surface waters groundwater across the Site. Hydrocarbons, especially aromatics and chlorinated solvents, are known to permeate plastic pipes. Assessment of the risk to water Direct infiltration in water pipes for any new supply will have to be undertaken as a Drinking water supply pipes No supply pipes requirement of the statutory undertakers who should be provided with a copy of this Assessment and provide recommendations for upgrading of potable water supply pipes, if considered necessary.
No elevated concentrations of contaminants have been identified within the soils across the Site. Any topsoil imported onto the Site Plants in landscaped and Root uptake No as part of the development works, or sourced from the Site and re- garden areas used, should be tested to confirm suitability, prior to, and once placed, in landscaped/garden areas.
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The Site has been classified as CS2 / Amber 1. This presents a low risk rating from ground gas to future Site residents. Ground gas protection measures will be necessary within the proposed Indoor exposure / development and should achieve a minimum score of 3.5 in line explosive hazard via with BS 8485:2015; however, given that elevated carbon dioxide BGS Recorded Mineral Site enclosed space Future residents Yes concentrations and flow rates were only recorded in the south of accumulation of ground the Site, it may be possible to ‘zone’ the Site once final gas development layouts are known, with less stringent gas protection measures in those areas that have continuously exhibited low ground gas levels.
Potentially unidentified ‘hotspots’ of As with all redevelopment works, a ‘hotspot’ protocol should be in contamination, which may be present in All pathways All receptors Unknown place for groundworkers to act upon during any future areas of the Site that have not been directly redevelopment of the Site. investigated
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9.0 Conclusions & Recommendations
9.1 Geotechnical Summary Shallow strip foundations are considered to be suitable for the Site, founded at a minimum depth of 1.00 m bgl to 1.50 m bgl within the firm clay strata encountered in the central area of the Site, and within the medium-dense sand deposits encountered across the remainder of the Site, respectively.
9.2 Contamination Issues The investigation has been carried out in order to provide information on the quality of the soil and groundwater beneath the Site in the context of land contamination and provide information on the ground gas regime beneath the Site for a residential end use. The assessment is being completed prior to the proposed redevelopment of the Site.
9.2.1 Human Health No elevated concentrations of Site-specific contaminants have been identified above their respective GAC in the context of a residential (with consumption of home grown produce) end use. No asbestos containing materials (ACM) or pesticide compounds were identified within the samples analysed.
Ground gas monitoring data indicates that the Site should be classified as CS2 – Amber 1, although this is only relevant to a location in the south of the Site area.
9.2.2 Controlled Waters Although elevated concentrations of heavy metals including cadmium, chromium, mercury and nickel have been identified within the groundwater at the Site, it is considered that the concentrations are representative of background concentrations, given that no potential source of heavy metal contamination has been identified, and that no elevated concentrations have been identified within the soil samples analysed. In addition, there are no potable abstractions located within 1 km of the Site. Therefore, it is considered that no further action is required.
9.3 Recommendations for Supplementary Work Based on the findings of this report, the following recommendations for supplementary works are made:
▲ In order to robustly characterise the ground gas regime at the Site, it is recommended that further ground gas monitoring is undertaken once development layouts have been finalised; ▲ Waste classification has not been undertaken as part of the scope of works, should it be proposed to dispose of materials from the Site, then specific additional investigations may be needed to classify the materials in accordance with current regulatory requirements; ▲ Any topsoil imported onto the Site as part of the development works, or sourced from the Site and re-used, should be tested to confirm suitability, prior to, and once placed, in landscaped / garden areas; ▲ Additional, unidentified localised areas of contamination may exist at the Site and an appropriate ‘hotspot’ protocol should be in place for groundworkers to act upon should such contamination be identified during the construction process; ▲ As with all development sites, groundworkers who are required to perform sub-surface work at the Site should be made aware of the known contaminants in soil and groundwater and the possibility of encountering additional localised low levels of contamination. Therefore, good standards of personal hygiene should be observed and appropriate levels of PPE utilised where necessary; ▲ Suitable dust suppression techniques will need to be implemented by the groundworkers during construction works; and
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▲ Confirmation should be sought from the Local Water Authority as to whether they will require upgraded pipework to be installed for new service installations.
Environment | Health & Safety | Sustainability Figure 1 – Site Location Map
Environment | Health & Safety | Sustainability Site Location
Scale: 1 / 500,000 @ A4
LEGEND
Site Boundary
Scale: 1 / 20,000 @ A4 Contains OS data © , Crown Copyright and Database Right (2016/2017)
TITLE: DRAWN BY: SCALE: PROJECT NO: Site Location Map EN To Scale@A4 CHECKED BY: REVISION: 17-0337.02 'GT20' (Parcels R1-R4), Sprowston GT 1 FIGURE NO: DATE: Norwich 12 September 2017 1 Figure 2 – Exploratory Hole Location Plan
Environment | Health & Safety | Sustainability LEGEND
Site Boundary
CPx Cable Percussion
TPx Trial Pit
CP201 TP202
TP201 CP202
TP203
TP204
TP205
TP206
CP203
TITLE: DRAWN BY: SCALE: PROJECT NO: Exploratory Hole Location Plan EN Not to Scale CHECKED BY: REVISION: 17-0337.02 'GT20' (Parcels R1-R4), Sprowston GT 1 FIGURE NO: DATE: Norwich 12 September 2017 2 Figure 3 – Corrected SPT, Depth and Strata Type
Environment | Health & Safety | Sustainability Corrected* SPT 'N'
0 10203040506070
0 17-0337.02 Phase 2 - GT20, Sprowston
Consortium of Taylor Wimpey, Persimmon Homes and Hopkins Homes
2
4
6 Depth (m bgl) (m Depth
8
10
HAPPISBURGH GLACIGENIC FORMATION SHERRINGHAM CLIFFS FORMATION
12 * Corrected for Energy Ratio only
TITLE: DWN: PROJECT NO: Corrected* SPT, Depth and Strata Type NH 17-0337.02 Phase 2 - GT20, Sprowston, Norwich DATE: FIGURE NO: 25/09/17 3
Appendix A - Limitations
Environment | Health & Safety | Sustainability
Limitations
The recommendations contained in this Report represent Delta-Simons professional opinions, based upon the information listed in the Report, exercising the duty of care required of an experienced Environmental Consultant. Delta-Simons does not warrant or guarantee that the Site is free of hazardous or potentially hazardous materials or conditions. Delta-Simons obtained, reviewed and evaluated information in preparing this Report from the Client and others. Delta-Simons conclusions, opinions and recommendations has been determined using this information. Delta- Simons does not warrant the accuracy of the information provided to it and will not be responsible for any opinions which Delta-Simons has expressed, or conclusions which it has reached in reliance upon information which is subsequently proven to be inaccurate. This Report was prepared by Delta-Simons for the sole and exclusive use of the Client and for the specific purpose for which Delta-Simons was instructed. Nothing contained in this Report shall be construed to give any rights or benefits to anyone other than the Client and Delta-Simons, and all duties and responsibilities undertaken are for the sole and exclusive benefit of the Client and not for the benefit of any other party. In particular, Delta-Simons does not intend, without its written consent, for this Report to be disseminated to anyone other than the Client or to be used or relied upon by anyone other than the Client. Use of the Report by any other person is unauthorised and such use is at the sole risk of the user. Anyone using or relying upon this Report, other than the Client, agrees by virtue of its use to indemnify and hold harmless Delta-Simons from and against all claims, losses and damages (of whatsoever nature and howsoever or whensoever arising), arising out of or resulting from the performance of the work by the Consultant.
Environment | Health & Safety | Sustainability
Appendix B – Risk Definitions
Environment | Health & Safety | Sustainability
Contaminated Land Risk Definitions
The following methodology is based on the methodology presented in CIRIA C552 Contaminated Land Risk Assessment: A Guide to Good Practice 2001. It requires the classification of the: ∆ Magnitude of the potential consequence (severity) of the Risk occurring: and ∆ Magnitude of the Probability (likelihood) of the Risk occurring.
The classifications are then compared to indicate the risk presented by each pollutant linkage.
Consequence to Receptor Definition Matrix
Human Health Controlled Waters Buildings/Services
Sensitive controlled water Severe Acute or chronic permanent pollution ongoing, or just Catastrophic collapse Consequence impact on human health. about to occur.
Medium Chronic permanent impact on Gradual pollution of sensitive Degradation of materials Consequence human health controlled water
Damage to building rendering it Mild Chronic temporary impact on Gradual pollution of non- unsafe.to occupy (eg foundation Consequence human health sensitive controlled water damage resulting in instability).
Non-permanent health effects Easily repairable effects of to human health (easily Minor damage to buildings, structures prevented by means such as Slight discoloration of water Consequence and services, i.e discoloration of personal protective clothing concrete etc).
Probability Definitions Probability Definition in Context Higher There is a pollution linkage and an event that either appears very likely in the short term and almost inevitable over the long term, or there is evidence at the receptor of harm or pollution. Positive evidence of source, pathway and receptor.
Likely There is a pollution linkage and all the elements are present and in the right place, which means that it is probable that an event will occur. Circumstances are such that an event is not inevitable, but possible in the short term and likely over the long term. Suspect source, pathway, and receptor
Low There is a pollution linkage and circumstances are possible under which an event could Likelihood occur. However, it is by no means certain that even over a longer period such event would take place, and is less likely in the shorter term.
Unlikely There is a pollution linkage but circumstances are such that it is improbable that an event would occur even in the very long term No evidence of hazard, pathway, and receptor
Document No: D124 Version: 1.0 Issue Date: 13/01/17 Author: R Griffiths Authorised by: Exec Group Page: 1 of 3 © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted.
Standard Risk Matrix
Consequence/ Magnitude of impact
Severe Medium Mild Minor
High Very High High Moderate Moderate/Low
Likely High Moderate Moderate/low Low
Low Likelihood Moderate Moderate/low Low Very Low Probability Unlikely Moderate/low Low Very Low Very Low
Classified risks and likely action
Significance Definition/Comments Level Very High Risk There is a high probability that severe harm could arise to a designated receptor from an identified hazard, OR, there is evidence that severe harm to a designated receptor is currently happening. This risk, if realised, is likely to result in a substantial liability. Urgent investigation (if not undertaken already) and remediation are likely to be required. Demonstrable contaminated land situation, highest threat & liability level, urgent action recommended.
High Risk Harm is likely to arise to a designated receptor from an identified hazard. Realisation of the risk is likely to present a substantial liability. Urgent investigation (if not undertaken already) is required and remedial works may be necessary in the short term and are likely over the longer term. Likely contaminated land situation, risk assessment and action recommended. Moderate It is possible that harm could arise to a designated receptor from an identified hazard. However, if is either relatively unlikely that any such harm would be severe, or if any harm were to occur it is more likely that the harm would be relatively mild Investigation (if not already undertaken) is normally required to clarify the risk and to determine the potential liability. Some remedial works may be required in the longer term. Plausible contaminated land situation, risk assessment and possible action recommended. Low Risk It is possible that harm could arise to a designated receptor from an identified hazard, but it is likely that this harm, if realised, would at worst normally be mild. Unlikely contaminated land situation, possible risk assessment and possible action. Very Low Risk There is a low possibility that harm could arise to a receptor. In the event of such harm being realised it is not likely to be severe. Negligible risk, no action recommended except vigilance for changes in conditions.
Document No: D124 Version: 1.0 Issue Date: 13/01/17 Author: R Griffiths Authorised by: Exec Group Page: 2 of 3 © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted.
Geotechnical Risk Classification
The geohazards listed in the report within Section 4 follow guidance presented in Clayton, C.R.I. (2001) Managing Geotechnical Risk, Thomas Telford and the Highways Agency document HD22/08 ‘Managing Geotechnical Risk’ (2008) which aims to identify and manage the geotechnical risks associated with a scheme throughout its lifespan, from planning to construction to maintenance.
For each geohazard the probability of the hazard occurring (P) has been considered together with the impact it would have (I) if it were to happen to calculate the risk rating between 1 and 25.
Risks that fall within Moderate, Significant and Severe categories below are considered to be substantial and are therefore listed within the report.
Probability (P) Impact (I) (R) Risk
Very Likely (VLk) 5 Very High (VH) 5 20 – Severe 25
Likely (Lk) 4 High (H) 4 15 – Substantial X = 19 Plausible (P) 3 Medium (M) 3 10 – Moderate 14
Unlikely (U) 2 Low (L) 2 5 – 9 Minor
Very Unlikely 1 Very Low (VL) 1 1 – 4 Negligible (VU)
Document No: D124 Version: 1.0 Issue Date: 13/01/17 Author: R Griffiths Authorised by: Exec Group Page: 3 of 3 © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted.
Appendix C – BACTEC Explosive Ordnance Desktop Threat Assessment
Environment | Health & Safety | Sustainability Explosive Ordnance Desktop Threat Assessment
Site: Sprowston, Norwich Client: Delta Simons
Ref: 7286TA Date: 5th September 2017
Dynasafe BACTEC Limited Make the world a safer place 9, Waterside Court, Galleon Boulevard, Crossways Business Park, Dartford, Kent, DA2 6NX, UK Office: +44 (0) 1322 284 550 www.bactec.com www.dynasafe.com Delta Simons Sprowston, Norwich
This document was written by, belongs to and is copyright to Dynasafe BACTEC Limited. It contains valuable Dynasafe BACTEC proprietary and confidential information which is disclosed only for the purposes of the client’s assessment and evaluation of the project which is the subject of this report. The contents of this document shall not, in whole or in part (i) be used for any other purposes except such assessment and evaluation of the project; (ii) be relied upon in any way by the person other than the client (iii) be disclosed to any member of the client’s organisation who is not required to know such information nor to any third party individual, organisation or government, or (iv) be copied or stored in any retrieval system nor otherwise be reproduced or transmitted in any form by photocopying or any optical, electronic, mechanical or other means, without prior written consent of the Managing Director, Dynasafe BACTEC Limited, 9 Waterside Court, Galleon Boulevard, Crossways Business Park, Dartford, Kent, DA2 6NX, United Kingdom to whom all requests should be sent. Accordingly, no responsibility or liability is accepted by Dynasafe BACTEC Limited towards any other person in respect of the use of this document or reliance on the information contained within it, except as may be designated by law for any matter outside the scope of this document.
Distribution
Copy No. Format Recipient
1 PDF Copy Delta Simons
2 PDF Copy Dynasafe BACTEC Limited
Date of Issue: 5th September 2017 Copy no. 1
Originator: ED
This Report has been produced in compliance with the Construction Industry Research and Information Association guidelines for the preparation of Detailed Risk Assessments in the management of UXO risks in the construction industry.
Dynasafe BACTEC Limited 9 Waterside Court, Galleon Boulevard, Crossways Business Park, Dartford, Kent, DA2 6NX Tel: +44 (0)1322 284550 Fax: +44 (0)1322 628150 Email: [email protected] www.bactecuxo.com
Registered in England No. 2601923. VAT Registration No. GB 573 6627 13 Delta Simons Sprowston, Norwich
Glossary of Terms
AAA Anti-Aircraft Artillery
ARP Air-raid Precautions
BDO Bomb Disposal Officer
EOD Explosive Ordnance Disposal (current term for “bomb” disposal)
HE High Explosive
HG Home Guard
IB Incendiary Bomb kg Kilogram
LCC London County Council
LM Land Mine
LSA Land Service Ammunition (includes grenades, mortars, etc.)
Luftwaffe German Air Force m bgl Metres Below Ground Level
MoD Ministry of Defence
OB Oil Bomb
PM Parachute Mine
RAF Royal Air Force
SI Site Investigation
SAA Small Arms Ammunition (small calibre cartridges used in rifles & machine guns)
UXB Unexploded Bomb
UXO Unexploded Ordnance
V-1 “Doodlebug” the first cruise type missile, used against London from June 1944. Also known as ‘Flying Bomb’.
V-2 The first ballistic missile, used against London from September 1944
WWI First World War (1914 -1918)
WWII Second World War (1939 – 1945)
Report: 7286TA ii Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
Table of Contents
Distribution ...... i Glossary of Terms ...... ii Table of Contents ...... iii Executive Summary ...... v Annexes ...... viii 1 Introduction ...... 1 1.1 Background ...... 1 2 Construction Industry Duties and Responsibilities ...... 1 2.1 The UK Regulatory Environment...... 1 2.2 The Health and Safety at Work Act, 1974 ...... 2 2.3 Construction (Design and Management) Regulation 2015 ...... 2 3 The Role of the Authorities and Commercial Contractors ...... 2 3.1 The Authorities ...... 2 3.2 Commercial Contractors ...... 3 4 This Report ...... 3 4.1 Aims and Objectives ...... 3 4.2 Risk Assessment Methodology ...... 3 4.3 Approach ...... 3 4.4 Sources of Information ...... 4 4.5 Reliability of Historical Records ...... 4 4.5.1 General Considerations ...... 4 4.5.2 Bombing Records ...... 4 5 The Site ...... 5 5.1 Site Location ...... 5 5.2 Site Description ...... 5 6 Scope of the Proposed Works ...... 5 7 Ground Conditions ...... 5 8 Site History ...... 5 8.1 Historical OS Mapping ...... 5 8.1.1 Pre-WWII ...... 6 8.1.2 Post-WWII...... 6 9 The Threat from Aerial Bombing ...... 6 9.1 General Bombing History of Norfolk and Norwich ...... 6 9.1.1 First World War ...... 6 9.1.2 Second World War ...... 6 9.1 Generic Types of WWII German Air-delivered Ordnance ...... 7 9.2 German Air-delivered Ordnance Failure Rate ...... 8 9.3 UXB Ground Penetration ...... 8 9.3.1 General Considerations ...... 8 9.3.2 The “j” Curve Effect ...... 9 9.3.3 Second World War Bomb Penetration Studies ...... 9 9.4 Initiation of Unexploded Bombs ...... 9 9.5 Bombing History of Sprowston ...... 10 9.5.1 Second World War Overview ...... 10 9.6 Second World War Bombing Records ...... 10 9.6.1 Bombing Statistics ...... 10 9.6.2 Written ARP Bombing Incident Records ...... 11 9.6.3 Anecdotal Evidence / Secondary Sources ...... 11 9.6.4 WWII-era RAF Aerial Photography ...... 12
Report: 7286TA iii Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
9.6.5 Abandoned Bombs ...... 12 9.7 Site Specific Bomb Penetration Considerations ...... 13 9.8 Likelihood of Post-raid UXO Detection ...... 13 9.8.1 Density of Bombing ...... 13 9.8.2 Bomb Damage Assessment ...... 14 9.8.3 Frequency of Access ...... 15 9.8.4 Ground Cover ...... 16 9.8.5 Bomb Failure Rate Assessment: ...... 18 10 The Threat from Allied Military Ordnance ...... 18 10.1 General ...... 18 10.2 Potential Sources of Explosive Ordnance ...... 19 10.2.1 WWII Army Activity ...... 19 10.2.2 WWII Anti-Invasion Defence Activity ...... 20 10.2.3 Anti-Aircraft Artillery ...... 21 10.3 The Threat Posed by British Unexploded Ordnance ...... 21 10.3.1 Land Service Ammunition (LSA) ...... 21 10.3.2 Small Arms Ammunition (SAA) ...... 22 10.3.3 Anti-Aircraft Shells ...... 22 11 Ordnance Clearance and Post-WWII Ground Works ...... 23 11.1 General ...... 23 11.2 EOD Bomb Disposal and Clearance Tasks ...... 23 11.3 Post War Redevelopment ...... 23 12 The Overall Explosive Ordnance Threat Assessment ...... 23 12.1 General Considerations ...... 23 12.2 The Risk that the Site was Contaminated with Unexploded Ordnance ...... 24 12.3 The Risk that Unexploded Ordnance Remains on Site ...... 25 12.4 The Risk that Ordnance may be Encountered during the Works ...... 25 12.5 The Risk that Ordnance may be Initiated ...... 25 12.6 The Consequences of Encountering or Initiating Ordnance ...... 25 12.7 Dynasafe BACTEC’s Assessment ...... 26 13 Proposed Risk Mitigation Strategy ...... 27 13.1 General ...... 27 13.2 Scope Specific Risk Mitigation Measures ...... 27 Bibliography ...... 28
Report: 7286TA iv Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
Executive Summary
THE SITE:
The site, centred on the approximate OS National Grid Reference: TG 26395 12272, is located in the Sprowston area, on the outskirts of Norwich, approximately 180m south of Sprowston Manor Hotel and Golf Club. It is bound to the north and east by open fields and agricultural land, to the south by Salhouse Road and to the west by an unnamed roadway and a housing development estate.
The site comprises several fields occupied by a mixture of grassland, pasture and dense vegetation. A number of cleared areas and hard-surfaced access roads are located across the site. Laundry Lane cuts across the centre of the study area.
THE PROPOSED WORKS:
It is understood that the site is to be redeveloped for residential use, comprising approximately 460 houses. No further details regarding the required ground works and no proposed development plan were available during the timeframe of this report.
Risk Assessment Methodology: In accordance with CIRIA guidelines this assessment has carried out research, analysed the evidence and considered the risks that the site has been contaminated with unexploded ordnance; that such items remained on site; that they could be encountered during any intrusive works and the consequences that could result. Appropriate risk mitigation measures have been proposed.
Explosive Ordnance Risk Rating: Taking into consideration the findings of this study, Dynasafe BACTEC considers the site to be heterogeneous and can therefore be divided into areas of LOW RISK and MEDIUM RISK from Unexploded Ordnance (UXO). This is based on the following:
GERMAN AIR-DELIVERED UXO:
• The Rural District of St Faiths & Aylesham, within which Sprowston was historically located, was predominantly agricultural in nature and sustained a low bombing density. However, the parish of Sprowston (and the site) bordered the county borough of Norwich, which sustained a high bombing density. • Therefore, as a town on the outskirts of Norwich, the site would likely have sustained a higher bombing density than the rest of the rural district. Note, however, no viable bombing targets were present in the vicinity of the site during WWII. • Anecdotal evidence indicates that the surrounding area, including the site, were subject to tip-and-run raids. A post-WWII aerial photograph shows two bomb craters forming a stick in line with the study area, approximately 130m to the south-west of the northern extent. Therefore, the possibility that a UXB from the same bomb load struck the site cannot be discounted. • The site was located within a sparsely populated agricultural area during the war. Therefore, there is a heightened risk of a UXB falling unnoticed within the site boundary. This is especially pertinent as the heaviest German air raids on the wider Norwich area took place at night. • The majority of the study area comprised open farm land or dense vegetation during the German bombing campaign. Had a UXB fallen here, it could easily have remained undetected, since the land will not have been accessed either regularly or frequently
Report: 7286TA v Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
during the Blitz. Additionally, due to its distance from any developed areas and relative lack of importance it is unlikely to have been subject to specific post-raid searches for UXO. • Furthermore, the resulting entry hole could easily have become obscured. Note, the entry hole of an SC50 UXB (the most commonly deployed German HE bombs) could have been as little as 20cm in diameter and therefore easily overlooked in dense crops, unmaintained pasture or ploughed soil.
BRITISH / ALLIED UXO
• The northern extent of the site encroaches onto the grounds of Sprowston Hall, which was requisitioned by the army during WWII for use by the Norfolk Division of Eastern Command. • Evidence obtained from external sources has indicated a number of features within the vicinity of the site regarding military activity. A rifle range, practice trenches and Nissen huts and unspecified stores (possibly ammunition related) have all been identified within a 315m radius of the site. It is therefore conceivable that surplus or unwanted ammunition may have been discarded within the grounds of Sprowston Hall, and therefore within the site boundary. Such activity has been consistently substantiated throughout England by recent ammunition finds of WWII vintage. • The 10th (Sprowston) Platoon formed the HG Company No. 3 with Catton, N.E. Norwich and Barnards Works Platoons to defend the area throughout WWII. HG units were reported to have assisted in guarding Sprowston Hall, and one pillbox was located approximately 140m south-west of the site. • Experience has shown that the ‘housekeeping’ of WWII soldiers was often poor with items of faulty, surplus or expended UXO often burnt, buried, misplaced or otherwise discarded on requisitioned civilian land. • No permanent HAA batteries were constructed within a 5km radius of the study area during WWII, however the possibility that temporary HAA guns were also brought to this area of Norfolk during the war cannot be discounted. Anecdotal evidence suggests that an AA and searchlight battery was brought to Sprowston Hall in 1939. Additionally, temporary guns would have been brought to the two local RAF airfields, RAF Rackheath and RAF Horesham St Faith (both within 5km of the site), during WWII. Therefore, the risk of unexploded AA shell contamination cannot be entirely ruled out.
THE RISK THAT UXO REMAINS ON SITE:
The lack of significant post-WWII redevelopment, development or substantial earthworks on site suggests the risk from UXO has not been mitigated to any significant degree.
Post-war agricultural activity or shallow groundworks across the site may have mitigated the risk from very shallow buried UXO however, would not have extended deep enough to completely mitigate this risk.
BOMB PENETRATION ASSESSMENT:
It has been assessed that a 500kg bomb would have had an approximate maximum bomb penetration depth of between 8-10m below WWII ground level. Penetration depth could potentially have been greater if the UXB was larger (though only 4% of German bombs used in WWII over Britain were of that size). Note that UXBs may be found at any depth between just below the WWII ground level and the maximum penetration depth.
Report: 7286TA vi Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
RECOMMENDED RISK MITIGATION MEASURES:
Dynasafe BACTEC recommends the following risk mitigation measures be deployed to support the proposed works:
• Site Specific Explosive Ordnance Safety and Awareness Briefings to all personnel conducting intrusive works within both Risk Zones • The Provision of Unexploded Ordnance Site Safety Instructions • Non-Intrusive Magnetometer Survey and Target Investigation (greenfield land only) • Explosive Ordnance Disposal (EOD) Engineer presence on site to support shallow intrusive works (brownfield alternative to a Non-Intrusive Survey) • Intrusive Magnetometer Survey of all pile locations deeper than 4m bgl, down to the maximum bomb penetration depth
Risk Map:
Report: 7286TA vii Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
Annexes
Annex A Site Location Maps
Annex B Recent Aerial Photograph
Annex C Site Plan
Annex D Pre and Post-WWII OS Maps
Annex E German Air-Delivered Ordnance
Annex F UXO Press Articles
Annex G RAF Aerial Photograph –1946
Annex H Recent UXO Incidents – Home Guard Phosphorus Incendiary Grenades
Annex I Land Service Ammunition
Annex J Small Arms Ammunition
Annex K Anti-Aircraft Artillery
Annex L Risk Map
Report: 7286TA viii Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich Explosive Ordnance Threat Assessment
In Respect of Sprowston, Norwich
1 Introduction
1.1 Background
Delta Simons has commissioned Dynasafe BACTEC Limited to conduct an Explosive Ordnance Threat Assessment for the Sprowston, Norwich site.
Unexploded Ordnance (UXO) presents a significant threat to construction projects in parts of the UK as a result of enemy actions during the two 20th Century World Wars and historic British and Allied military activity.
One of the legacies of this conflict is buried unexploded air-dropped bombs or anti-aircraft projectiles resulting from the failure of a proportion of the weapons to function as designed. It is commonly accepted that the failure rate of these munitions was approximately 10% and, depending on their shape, weight, velocity and ground conditions, many penetrated the ground and came to rest at depth.
In addition, it is estimated that over 20% of the UK landmass has been used by the military at some point and between 2006 and 2009, over 15,000 items of British / Allied ordnance (excluding small arms ammunition) were found on UK construction sites (CIRIA).
Intensive efforts were made during and after the war to locate and render safe all UXO but, unsurprisingly, not all were found and dealt with. This is evidenced by the regular, on-going discoveries of UXO during construction-related intrusive ground works.
As a result of a generally increased risk awareness amongst professionals involved in ground engineering works and proactive health and safety measures, the threat to life and limb from UXO has been minimised. However even the simple discovery of a suspected device during on-going works can cause considerable disruption to production and cause unwanted delays and expense.
Such risks can be more fully addressed by a better understanding of the site-specific threat and the implementation of appropriate risk mitigation measures.
2 Construction Industry Duties and Responsibilities
2.1 The UK Regulatory Environment
There is no specific legislation covering the management and control of the UXO risk in the UK construction industry but issues regarding health and safety are addressed under a number of regulatory instruments, as outlined below.
In practice, the regulations impose a responsibility on the construction industry to ensure that they discharge their obligations to protect those engaged in ground-intrusive operations (such as archaeology, site investigation, drilling, piling or excavations) from any reasonably foreseeable UXO risk.
Report: 7286TA 1 Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
2.2 The Health and Safety at Work Act, 1974
The Act places a duty of care on an employer to put in place safe systems of work to address, as far as is reasonably practicable, all risks (to employees and the general public) that are reasonably foreseeable.
2.3 Construction (Design and Management) Regulation 2015 CDM 2015 ensures that health and safety within the construction industry is continually improved: • Works are sensibly planned and managed. • Competent staff are engaged in the works. • Risks are identified and managed. • All parties cooperate and coordinate activities. • Communication flows to those who require it. • Workers are consulted and engaged about risks and how they are being managed. In line with CDM2 015 legislation, Dynasafe BACTEC Limited are able to assist parties in their discharge of CDM duties as follows: • Assist Principal Designers with pre-construction information and risk assessments. • Assist the Designer with the Designer’s Risk Assessment. • Issue UXO risks as have been identified, and manage risks accordingly. • Assist the Principal Contractor with the construction phase information, in particular risk assessments and mitigation strategies. • Plan, manage and monitor survey and clearance works under Dynasafe BACTEC Limited’s control.
Other relevant legislation includes the “Management of Health and Safety at Work Regulations 1999” and “The Corporate Manslaughter and Corporate Homicide Act 2007”.
3 The Role of the Authorities and Commercial Contractors
3.1 The Authorities
The Police have the responsibilities for co-ordinating the emergency services in the case of an ordnance-related incident on a construction site. They will make an initial assessment (i.e. is there a risk that the find is ordnance or not?) and if they judge necessary impose a safety cordon and/or evacuation and call the military authorities (JSEODOC - Joint Services Explosive Ordnance Disposal Operations Centre) to arrange for investigation and/or disposal. In the absence of an EOD specialist on site many Police Officers will use the precautionary principle, impose cordon(s)/evacuation and await advice from the JSEODOC.
The priority given to the request by JSEODOC will depend on their judgement of the nature of the threat (ordnance, location, people and assets at risk) and the availability of resources. They will respond immediately or as resources are freed up. Depending on the on-site risk assessment the item of ordnance may be removed or demolished (by controlled explosion) in situ. In the latter case additional cordons and/or evacuations may be necessary.
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Note that the military authorities will only carry out further investigations or clearances in very high profile or high-risk situations. If there are regular ordnance finds on a site, the JSEODOC may not treat each occurrence as an emergency and will encourage the construction company to put in place alternative procedures (i.e. the appointment of a commercial contractor) to manage the situation and relieve pressure from the JSEOD disposal teams.
3.2 Commercial Contractors
In addition to pre-construction site surveys and follow-on clearance work, a commercial contractor is able to provide a reactive service on construction sites. The presence of a qualified EOD Engineer with ordnance recognition skills will avoid unnecessary call-outs to the authorities and the Contractor will be able to arrange for the removal and disposal of low risk ordnance. If high risk ordnance is discovered actions will be co-ordinated with the authorities with the objective of causing the minimum possible disruption to site operations whilst putting immediate, safe and appropriate measures in place.
4 This Report
4.1 Aims and Objectives
The aim of this report is to examine the possibility of encountering any explosive ordnance during any intrusive works at the Sprowston, Norwich site. Risk mitigation measures will be recommended, if deemed necessary, to eliminate or reduce the threat from explosive ordnance during the envisaged works. The report follows the CIRIA Guidelines.
4.2 Risk Assessment Methodology
The following issues will be addressed in the report:
• The risk that the site was contaminated with unexploded ordnance. • The risk that UXO remains on site. • The risk that ordnance may be encountered during any intrusive works. • The risk that ordnance may be initiated. • The consequences of initiating or encountering ordnance.
Risk mitigation measures, appropriate to the assessed level of risk and site conditions, will be recommended if required.
4.3 Approach
In preparing this Explosive Ordnance Threat Assessment Report, Dynasafe BACTEC has considered general and, as far as possible, site specific factors including:
• Evidence of German bombing and delivery of UXBs. • Site history, occupancy and conditions during WWII. • The legacy of Allied military activity. • Details of any known EOD clearance activity. • The extent of any post war redevelopment. • Scope of the current proposed works.
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4.4 Sources of Information
Dynasafe BACTEC has carried out detailed historical research for this Explosive Ordnance Threat Assessment including accessing military records and archived material held in the public domain and in the MoD.
Material from the following sources has been consulted:
• The National Archives. • Norfolk County Council. • Landmark Maps. • Relevant information supplied by Delta Simons. • Available material from 33 Engineer Regiment (EOD) Archive. • Dynasafe BACTEC’s extensive archives built up over many years of research and hands- on Explosive Ordnance Disposal activities in the UK. • Open sources such as published books, local historical records and the internet.
4.5 Reliability of Historical Records
4.5.1 General Considerations
This report is based upon research of historical evidence. Whilst every effort has been made to locate all relevant material Dynasafe BACTEC cannot be held responsible for any changes to the assessed level of risk or risk mitigation measures based on documentation or other information that may come to light at a later date.
The accuracy and comprehensiveness of wartime records is frequently difficult or impossible to verify. As a result, conclusions as to the exact location, quantity and nature of the ordnance threat can never be definitive but must be based on the accumulation and careful analysis of all accessible evidence. Dynasafe BACTEC cannot be held responsible for inaccuracies or gaps in the available historical information.
4.5.2 Bombing Records
During WWII, considerable efforts were expended in recording enemy air raids. Air Raid Precautions (ARP) wardens were responsible for making records of bomb strikes either through direct observation or by post-raid surveys. However, their immediate priority was to deal with casualties and limit damage, so it is to be expected that records are often incomplete and sometimes contradictory. Record keeping in the early days of bombing was not comprehensive and details of bombing in the early part of the war were sometimes destroyed in subsequent attacks. Some reports may cover a single attack, others a period of months or the entire war.
Records of raids that took place on sparsely or uninhabited areas were often based upon third party or hearsay information and are not always reliable; records of attacks on military or strategic targets were often maintained separately from the general records and have not always survived.
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5 The Site
5.1 Site Location
The site is located in the Sprowston area, on the outskirts of Norwich, approximately 180m south of Sprowston Manor Hotel and Golf Club. It is bound to the north and east by open fields and agricultural land, to the south by Salhouse Road and to the west by an unnamed roadway and a housing development estate.
The site is centred on the approximate OS National Grid Reference: TG 26395 12272.
Site Location Maps are presented in Annex A.
5.2 Site Description
The site comprises several fields occupied by a mixture of grassland, pasture and dense vegetation. A number of cleared areas and hard-surfaced access roads are located across the site. Laundry Lane cuts across the centre of the study area.
A Recent Aerial Photograph of the site presented in Annex B.
6 Scope of the Proposed Works
It is understood that the site is to be redeveloped for residential use, comprising approximately 460 houses. No further details regarding the required ground works and no proposed development plan were available during the timeframe of this report.
A Site Plan is presented in Annex C.
7 Ground Conditions
Published data obtained from the British Geological Survey for a borehole sunk 270m north of the site in 1981 records the following shallow geology: • 0.3m of Topsoil • 0.6m of Loam • 13.4m of Brown Sand Note, the BGS 1:50,000 scale mapping indicates that the site passes through two types of geology. The south of the site is underlain by Sheringham Cliffs Formation (Sand & Gravel) superficial deposits and Crag Group (Sand and Gravel) bedrock. The north of the site is generally underlain by Happisburgh Glacigenic Formation (Diamicton) superficial deposits and Crag Formation bedrock.
8 Site History
8.1 Historical OS Mapping
Latest available pre-WWII and earliest available post-WWII 1:10,560 scale OS maps of the site were acquired from Landmark Maps and provided by Delta Simons. These are presented in Annex D and described below.
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8.1.1 Pre-WWII
The 1938 map shows the site to be occupied by several fields. Those at the north and south of the study area are occupied by more dense vegetation / mature trees. Also, Arnup’s Belt is labelled in the centre of the northern section and the Round Hill Plantation in the south.
The surrounding area is predominantly agricultural in nature, with Sprowston Hall located to the north and White House to the east being the nearest residential areas.
The immediate surrounding area is predominantly agricultural / rural in nature.
8.1.2 Post-WWII
The 1950 map does not show any significant changes within the site boundary or across the wider surrounding area.
9 The Threat from Aerial Bombing
9.1 General Bombing History of Norfolk and Norwich
9.1.1 First World War
London and Eastern England suffered aerial bombardment during WWI, beginning with indiscriminate night raids by Zeppelin airships. However as British defensive measures became more effective and aircraft development progressed, the German military switched to daylight raids by fixed wing aircraft in June 1917.
A WWI bomb plot map and air raid sketch map (not annexed) indicate that WWI ordnance was dropped on Norwich and its surrounding area. Furthermore, a map showing the air raids and naval bombardments over the whole of England was reviewed (not annexed), which indicates that bombs were dropped from Zeppelins just east of Norwich. This may have affected the site.
Due to the small scale of the maps it is impossible to pinpoint exactly where bombs fell and therefore the risk from encountering WWI ordnance cannot be totally discounted. Note, that the map does only show one air raid over the area.
However, WWI bombs were generally smaller than those used in WWII and were dropped from a lower altitude, resulting in limited UXB penetration depths. Aerial bombing was often such a novelty at the time that it attracted public interest and even spectators to watch the raids in progress. For these reasons, there is a limited risk that UXBs passed undiscovered in the urban environment. When combined with the relative infrequency of attacks and an overall low bombing density the threat from WWI UXBs is considered low and will not be further addressed in this report.
9.1.2 Second World War
At the start of WWII, the Luftwaffe planned to destroy key military installations, including RAF airfields and Royal Navy bases, during a series of daylight bombing raids. After the Battle of Britain these tactics were modified to include both economic and industrial sites. Targets included dock facilities, railway infrastructure, power stations, weapon manufacturing plants and gas works. As a result of aircraft losses, daylight raids were reduced in favour of attacking targets under the cover of darkness.
As the war progressed the strategy changed to one of attempting to destroy the morale of the civilian population by the “carpet bombing” of British towns. Located near the eastern coast of England, Norfolk and the city of Norwich provided an easily accessible target for Luftwaffe
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bombing raids. 27 air raids occurred over Norwich throughout the early years of the war, resulting in 81 deaths.
However, the greatest destruction caused to the city came in 1942 with the commencement of the Baedeker Raids against culturally important cities and towns in England. Carried out as retaliation for British raids on the German port of Lubeck, the targets had little or no military value and aimed to spread terror amongst the civilian population.
On the night of the 27th - 28th April 1942 Norwich experienced a heavy raid, with the greatest damage caused to the north and north-western areas of the city. German bombers returned on the night of the 29th April, dropping a combination of incendiary and HE bombs over large areas of the city. The final night of the Baedeker Blitz occurred on the 1st May.
The unexpected nature of the raids meant that insufficient defences were in place. By the time barrage balloons had been positioned over the town in the following days, it was too late.
There were further attacks in May 1942 and a heavy bombardment on 26th and 27th June in which the Cathedral was badly damaged. Sporadic air raids by small numbers of or solitary aircraft then continued until the end of the war.
The Norwich air-raid casualty list amounted to 340 killed and 1,092 seriously injured. A total of 681 high explosive bombs were dropped within the city boundary during the war. As a result, 30,354 dwellings and 975 industrial establishments, offices / businesses or public buildings were damaged or destroyed.
9.1 Generic Types of WWII German Air-delivered Ordnance
The nature and characteristics of the ordnance used by the Luftwaffe allows an informed assessment of the hazards posed by any unexploded items that may remain today. Detailed illustrations of German air delivered ordnance are presented at Annex E.
• HE Bombs: In terms of weight of ordnance dropped, HE bombs were the most frequent weapon deployed. Most bombs were 50kg, 250kg or 500kg (overall weight, about half of which was the high explosive) though large bombs of up to 2,000kg were also used. HE bombs had the weight, velocity and shape to easily penetrate the ground intact if they failed to explode. Post-raid surveys would not always have spotted the entry hole or other indications that a bomb penetrated the ground and failed to explode and contemporary ARP documents describe the danger of assuming that damage, actually caused by a large UXB, was due to an exploded 50kg bomb. Unexploded HE bombs therefore present the greatest risk to present–day intrusive works. • Blast Bombs/Parachute Mines: Blast bombs generally had a slow rate of descent and were extremely unlikely to have penetrated the ground. Non-retarded mines would have shattered on most ground types, if they had failed to explode. There have been extreme cases when these items have been found unexploded, but this was where the ground was either very soft or where standing water had reduced the impact. BACTEC does not consider there to be a significant threat from this type of munition on land. • Large incendiary bombs: This type of bomb ranged in size from 36kg to 255kg and had a number of inflammable fill materials (including oil and white phosphorus), and a small explosive charge. They were designed to explode and burn close to the surface but their shape and weight meant that they did have penetration capability. If they penetrated the ground complete combustion did not always occur and in such cases they remain a risk to intrusive works.
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• 1kg Incendiary Bombs (IB): These bombs, which were jettisoned from air-dropped containers, were unlikely to penetrate the ground and in urban areas would usually have been located in post-raid surveys. However, if bombs did not initiate and fell in water or dense vegetation, or became mixed with rubble in bomb damaged areas they could have been overlooked. Some variants had explosive heads and these present a risk of detonation during intrusive works. • Anti-personnel (AP) Bomblets: AP bombs had little ground penetration ability and should have been located by the post-raid survey unless they fell into water, dense vegetation or bomb rubble. • Specialist Bombs (smoke, flare, etc): These types do not contain high explosive and therefore a detonation consequence is unlikely. They were not designed to penetrate the ground.
9.2 German Air-delivered Ordnance Failure Rate
Based on empirical evidence, it is generally accepted that 10% of the German HE bombs dropped during WWII failed to explode as designed. This estimate is probably based on the statistics of wartime recovered UXBs and therefore will not have taken account of the unknown numbers of UXBs that were not recorded at the time, and is probably an underestimate.
The reasons for failures include:
• Fuze or gaine malfunction due to manufacturing fault, sabotage (by forced labour) or faulty installation. • Clockwork mechanism failure in delayed action bombs. • Failure of the bomber aircraft to arm the bombs (charge the electrical condensers which supplied the energy to initiate the detonation sequence) due to human error or equipment defect. • Jettison of the bomb before it was armed or from a very low altitude. Most likely if the bomber was under attack or crashing.
War Office Statistics document that a daily average of 84 bombs which failed to function were dropped on civilian targets in Great Britain between 21st September 1940 and 5th July 1941. 1 in 12 of these (probably mostly fitted with time delay fuzes) exploded sometime after they fell - the remainder were unintentional failures.
From 1940 to 1945 bomb disposal teams dealt with a total of 50,000 explosive items of 50kg and over (i.e. German bombs), 7,000 AAA shells and 300,000 beach mines. These operations resulted in the deaths of 394 officers and men. However, UXO is still regularly encountered across the UK (see recent press articles, Annex F-1).
9.3 UXB Ground Penetration
9.3.1 General Considerations
The actual penetration depth of aerial delivered bombs into the ground will have been determined by the mass and shape of the bomb, the velocity and angle of the bomb on impact (dependent on the height of release) and the nature of the ground and ground cover; the softer the ground, the greater the potential penetration. Peat, alluvium and soft clays are easier to penetrate than gravel and sand. Bombs are brought to rest or are commonly deflected by bedrock or large boulders.
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9.3.2 The “j” Curve Effect
An air-dropped bomb falling from normal bombing altitude (say 5,000m) into homogeneous ground will continue its line of flight but turn in an upwards curve towards the surface as it comes to rest. This offset from vertical is generally thought to be about one third of the penetration depth, but can be up to 15m depending on ground conditions or the bomb’s angle of impact.
9.3.3 Second World War Bomb Penetration Studies
During WWII, the Ministry of Home Security undertook a major study on actual bomb penetration depths, carrying out statistical analysis on the measured depths of 1,328 bombs as reported by Bomb Disposal, mostly in the London area. They then came to conclusions as to the likely average and maximum depths of penetration of different sized bombs in different geological strata.
The median penetration of 430 x 50kg German bombs in London Clay was 4.6m and the maximum penetration observed for the SC50 bomb was 9m.
They concluded that the largest common German bomb, 500kg, had a likely penetration depth of 6m in sand or gravel but 8.7m in clay. The maximum observed depth for a 500kg bomb was 10.2m and for a 1,000kg bomb 12.7m. Theoretical calculations suggested that significantly greater penetration depths were probable.
9.4 Initiation of Unexploded Bombs
Unexploded bombs do not spontaneously explode. All high explosive requires significant energy to create the conditions for detonation to occur. In the case of unexploded German bombs discovered within the construction site environment, there are a number of potential initiation mechanisms:
• Direct impact onto the main body of the bomb: Unless the fuze or fuze pocket is struck, there needs to be a significant impact (e.g. from piling or large and violent mechanical excavation) to initiate a buried iron bomb. Such violent action can cause the bomb to detonate. • Re-starting the clock timer in the fuze: Only a small proportion of German WWII bombs employed clockwork fuzes. It is probable that significant corrosion has taken place within the fuze mechanism over the last 60 years that would prevent clockwork mechanisms from functioning, nevertheless it was reported that the fuze in a UXB dealt with by 33 EOD Regiment in Surrey in 2002 did re-commence. • Induction of a static charge, causing a current in an electric fuze: The majority of German WWII bombs employed electric fuzes. It is probable that significant corrosion has taken place within the fuze mechanism over the last 60 years such that the fuze circuit could not be activated. • Friction impact initiating the (shock-sensitive) fuze explosive: This is the most likely scenario resulting in the bomb detonating.
Annex F-2 details UXB incidents where intrusive works have caused UXBs to detonate, resulting in death or injury and damage to plant.
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9.5 Bombing History of Sprowston
9.5.1 Second World War Overview
During WWII, Sprowston, on the outskirts of Norwich, was predominantly agricultural in character and subsequently experienced moderate levels of enemy bombing.
A Luftwaffe Target Map (not annexed) identifies Barnards factory, situated approximately 1.2km south-west of the site, as a viable Luftwaffe bombing target. This was reportedly bombed several times over the course of WWII. Additionally, the town’s proximity to the centre of Norwich meant that the area was also vulnerable to overspill bombing and ‘Tip and Run’ incidents, in which the enemy would prematurely jettison its load if confronted with anti- aircraft fire or fighters based at nearby batteries / airfields (the nearest fighter squadrons based at RAF Horsham St Faith, approximately 3.5km north-west of the site). Consequently, Sprowston reportedly sustained several attacks during the war.
Records of bombing incidents in the civilian areas of Norfolk were collected by the Air Raid Precautions wardens and collated by the Civil Defence Office. Some other organisations, such as the railways, maintained separate records.
Records would be in the form of typed or hand-written incident notes, maps and statistics. Bombing data was carefully analysed, not only due to the requirement to identify those parts of the capital most needing assistance, but also in an attempt to find patterns in the Germans’ bombing strategy in order to predict where future raids might take place. Site specific bombing records were obtained and are described below.
9.6 Second World War Bombing Records
9.6.1 Bombing Statistics
The following table summarises the quantity of German bombs (excluding 1kg incendiaries and anti-personnel bombs) falling on the Rural District of St Faiths & Aylesham, within which the site was historically located, and also the County Borough of Norwich, neighbouring the Parish of Sprowston, between 1940 and 1945:
Record of German Ordnance Dropped
Administrative Area RD of St Faiths & Aylesham CB of Norwich Area Acreage 93,119 7,898 High Explosive Bombs (all types) 506 561 Parachute Mines 11 0 Oil Bombs 1 2 Phosphorus Bombs 3 24 Fire Pot 48 84 Pilotless Missile (V1) 0 0 Long Range Rocket (V2) 7 0 Total 576 671 Items Per 1,000 Acres 6.2 85.0
Detailed records of the quantity and locations of the 1kg incendiary and anti-personnel bombs were not routinely maintained by the authorities as they were frequently too numerous to record. However, Bowyer, in his publication Air Raid! The Enemy Air Offensive
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Against East Anglia 1939-451, notes that 19,620 x 1kg incendiary bombs were dropped over Norwich during WWII.
Although the incendiaries are not particularly significant in the threat they pose, they nevertheless are items of ordnance that were designed to cause damage and inflict injury and should not be overlooked in assessing the general risk to personnel and equipment. The anti-personnel bombs were used in much smaller quantities and are rarely found today but are potentially more dangerous. This table does not include UXO found during or after WWII.
Note, as Sprowston Parish (and the site) was historically situated near to the border of Norwich, the bombing density is likely to be higher than for much of the Rural District of St Faiths & Aylesham.
Bowyer also notes that 396 x HE bombs, 28 x unexploded HE bombs and 121 unclassified HE bombs (18 x unexploded) landed on Norwich during WWII. Also, 2 x 50kg Phosphorus bombs (22 x unexploded), 76 fire Pots (8 x unexploded), and 2 x oil bombs also landed on the city. This is roughly in line with the official statistics.
9.6.2 Written ARP Bombing Incident Records
Written ARP records for the Rural District of St Faiths & Aylesham were sought from Norfolk Record Office. However, no records for Sprowston were available within the timeframe of this report. The local archives have been contacted. Should their response indicate any findings that affect this report, Delta Simons will be immediately contacted.
9.6.3 Anecdotal Evidence / Secondary Sources
Evidence of bombing incidents in Sprowston was sought from a variety of online and published sources. The following table records bombing in the vicinity of the site and the surrounding area. Note, this cannot be considered a comprehensive list of all bombing over the site during WWII.2
Date Weapon Location Remarks
German bomber flew unopposed from the Thorpe direction towards Sprowston Hall, almost parallel with Blue Boar Blue Boar Woods, Lane (possibly over the site), dropping Sprowston (approx. about 8 bombs but failing to hit n/k ~8 x HE bombs 395m south-west of anything. They exploded in Blue Boar site) Woods and in the present-day Tesco car park (290m south-west of the site). Barnards factory was likely the target but instead was a tip & run.
Mousehold Lane 13/08/1942 HE bombs (2.15km south- All houses on the road caught the blast west)
1 Bowyer, 1986 2 http://www.sprowstonheritage.org.uk Ramsey, 1987 Bowyer, 1986
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Tip and Run raid over Norwich: Barnards Factory 09/07/1940 HE bombs (1.5km south-west) Factory was bombed very badly, damaged Salhouse Road One bomb blast caused blast damage n/k HE bomb (0km – 2.2km north to Mousehold Lane or south east) Cozens Hardy n/k HE bomb Road (1.2km south- Bomb fell into a pond west) Edwards Road n/k HE bomb Direct hit on the shop (1.3km west) Possibly anti- 26 unexplained bombs fell, thought to RD of St Faiths & 31/08/1940 personnel be anti-personnel. Exact locations Aylesham bombs unknown.
29/04/1941 IBs St Faiths Location unspecified
Barnards Factory, Several bombs dropped on the factory, 27/02/1941 HE bombs Salhouse Road some damage caused to the building. (1.5km south-west) No casualties.
9.6.4 WWII-era RAF Aerial Photography
Historical RAF aerial photography of the site, dated 1946, was obtained from Norfolk County Council and is presented in Annex G.
This image, taken approximately one year after the end of WWII, shows the site as it appears on the OS mapping. The majority of the study area is occupied by agricultural fields, with a small area of dense vegetation in the south. The northern extent, however, occupies part of the grounds of Sprowston Hall (see Section 10.2.1).
No evidence of severe bomb damage, such as HE bomb craters or ground disturbance, is visible within the site boundary. However, two likely bomb craters are evident approximately 130m south-west of the northern half of the site. Note, this stick of bombs is aligned with the northern extent of the site.
Such features could have remained only temporarily in worked / agricultural land, being in- filled and ploughed prior to this photograph being taken. Therefore, the possibility of further craters on or close to the site cannot be discounted.
9.6.5 Abandoned Bombs
A post-air raid survey of buildings, facilities and installations would have included a search for evidence of bomb entry holes. If evidence were encountered, Bomb Disposal Officer teams would normally have been requested to attempt to locate, render safe and dispose of the bomb. Occasionally evidence of UXBs was discovered but due to a relatively benign position, access problems or a shortage of resources the UXB could not be exposed and rendered safe. Such an incident may have been recorded and noted as an Abandoned Bomb.
Given the inaccuracy of WWII records and the fact that these bombs were ‘abandoned’, their locations cannot be considered definitive, nor the lists exhaustive. The MoD states that ‘action to make the devices safe would be taken only if it was thought they were unstable’. It should be noted that other than the ‘officially’ abandoned bombs, there will inevitably be
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UXBs that were never recorded. Dynasafe BACTEC holds no records of officially registered abandoned bombs at or near the site.
9.7 Site Specific Bomb Penetration Considerations
When considering an assessment of the bomb penetration at Sprowston, Norwich site, the following parameters would be used:
• WWII Geology - The south of the site is underlain by Sheringham Cliffs Formation (Sand & Gravel) superficial deposits and Crag Group (Sand and Gravel) bedrock. The north of the site is underlain by Happisburgh Glacigenic Formation (Diamicton) superficial deposits and Crag Formation bedrock. • Impact Angle and Velocity - 80-90O from horizontal and 267 metres per second. • Bomb Mass and Configuration - The 500kg SC (General Purpose) HE bomb, without retarder units or armour piercing nose. This was the largest of the common bombs used against Britain.
Taking into account the above-mentioned factors it has been assessed that a 500kg bomb would have had an approximate maximum bomb penetration depth of 8-10m below WWII ground level. Penetration depth could potentially have been greater if the UXB was larger (though only 4% of German bombs used in WWII over Britain were of that size). Note that UXBs may be found at any depth between just below the WWII ground level and the maximum penetration depth.
9.8 Likelihood of Post-raid UXO Detection
Utilising the available historical bombing records as reviewed in Section 9.6, it is possible to make an assessment of the likelihood that evidence of UXO would have been noted on a site during the war and the incident dealt with or recorded at the time. Factors such as bombing density, frequency of access, ground cover, damage and failure rate have been taken into consideration.
9.8.1 Density of Bombing
Bombing density is an important consideration for assessing the possibility that UXBs remain in an area. A very high density of bombs will have increased the likelihood of errors in record keeping at the time, as civil defence personnel and emergency services may have been overwhelmed. A higher density of bombing also increases the number of UXBs actually occurring in a given area.
The type and specific location of recorded bomb strikes is also an important consideration. If a stick of bombs (one individual aircraft’s bomb load) is plotted in line with a site or is shown to straddle a site, then this raises the possibility that an unrecorded UXB from the same stick struck that site.
Based on wartime records or secondary source information, what was Low-Moderate the bombing density over the site?
Was the site ever subjected to one or more large-scale (>100 tons of No ordnance) night time Blitz raids? How many HE, Parachute Mine, Oil Incendiary, Phosphorus Incendiary or Fire Pot bombs (large bombs) were recorded within a At least 3 300m radius of the site?
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What is the distance between the site boundary and the closest 130m south-west recorded large bomb strike?
Were any nearby sticks of large bombs recorded in line with the site? Yes
Were any 1kg incendiary bomb showers recorded over the site? Not known
Additional Anecdotal evidence of an undated raid notes at least 8 HE bombs dropped near Sprowston Hall, with the flight path of the bomber possibly passing over the site. comments: This raid could conceivably have resulted in a UXB strike on site.
9.8.2 Bomb Damage Assessment
If structures or hard-standing sustained substantial HE blast damage or fire damage (resulting from incendiary bombs), quantities of rubble will have persisted on site for a time and debris will have been strewn across any adjacent open ground. Note, in Blitzed cities / towns throughout Britain, bomb sites were often not cleared of rubble until after the war and mid-war repairs to buildings were only carried out on the most vital facilities, such as power stations, gas works, weapons factories, etc.
If a building sustained bomb damage to its upper floors, but the ground floor survived the incident intact, then any subsequent UXB strike to the structure will still have caused obvious damage, at ground floor level, which would have been reported and dealt with at the time.
A HE bomb strike in open ground will have resulted in a large crater and a degree of soil disturbance in the immediate vicinity. Any subsequent UXB strike to such ground conditions will not have resulted in an easily identifiable entry hole and as such is likely to have gone unnoticed.
A comparison of the historical records confirms that buildings within the site n/a boundary sustained serious bomb damage.
Direct or indirect evidence of HE bomb craters in open ground (within the site boundary) has been found. In London and south-east England, the German V1 Flying Bomb and V2 Long Range Rocket campaigns caused widespread devastation. However, these weapons began to fall on Britain after the final significant Luftwaffe air raids had occurred. Therefore, any serious bomb damage caused by a nearby V Weapon strike does not necessarily indicate an increased risk of Luftwaffe freefall UXB contamination, as is described above.
Buildings on site were seriously damaged by a V1 and / or V2 strike. n/a
However, if Luftwaffe freefall bombs are recorded in close proximity to buildings which appear to have also been damaged by a V Weapon strike, then it is quite possible that these buildings suffered serious damage during the September 1940 – May 1944 Blitz campaigns and the resulting evidence of this initial damage was then erased by the post- May 1944 V Weapon strike.
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Buildings on site could have been seriously damaged prior to the nearby V1 n/a or V2 strike?
Additional comments: n/a
9.8.3 Frequency of Access
A UXB strike at a site where human access was frequent would have had a greater chance of being observed, reported and recorded than at a site which was unoccupied / undeveloped / subject to infrequent or irregular access. The importance of a site or facility to the war effort is also an important consideration. Many vital factories, gas works, power stations, docks, etc had a team of Fire Watchers tasked with observing local air raids. They were mainly responsible for extinguishing 1kg incendiaries before they could start a fire as well as reporting any UXB strikes. However anecdotal evidence indicates that Fire Watchers did not always turn up for their shifts, in part due to the danger associated with the job, and therefore this factor should not be taken into account unless site specific evidence has been identified.
In frequently bombed cities / towns, ARP Wardens were tasked with carrying out searches for UXBs within recently bombed residential areas and schools. Similarly, many large organisations, such as the docks or large factory complexes, had their own dedicated ARP teams who would perform similar duties at these commercial sites. However, such UXB mitigating activities should not be assumed in the absence of site specific evidence.
With the mass evacuation of children to the countryside, many schools in the largest cities were closed during the Blitz. However, many of these schools were then requisitioned by the Civil Defence authorities to be utilised as night time First Aid posts and reception centres (providing emergency accommodation for bombed out civilians). Therefore, an increased level of access is likely at these locations.
The site was situated in a densely populated urban area during WWII and therefore would have been accessed at the outbreak of WWII.
The site was exclusively developed during WWII.
The site was partially developed during WWII.
Buildings on site survived WWII intact and therefore likely remained inhabited or in use, suggesting these localities and their immediate environs were n/a accessed throughout the war. The site was crossed by roads / pavements or footpaths which would have been regularly used / subject to daily footfall. The site was occupied by small residential back yards / gardens, likely to have been put to use for cultivation as a result of the government’s Dig for Victory Campaign.
The site was occupied by a school during WWII.
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Part of the site is likely to have been subject to post-raid searches for UXO.
Buildings on site sustained serious bomb damage and as a result were likely abandoned (along with any associated gardens / open ground) for the n/a remainder of the war.
A UXB strike at a site where human access was infrequent would have had a lesser chance of being observed, reported and recorded than at a site which was developed and subject to frequent and / or regular access. A UXB strike during a night time raid is more likely to have fallen unobserved than one dropped during a daylight attack. Note, the Luftwaffe tended to carry out its large-scale air raids over heavily defended cities / towns at night, to hamper the British anti-aircraft defences.
If buildings sustained bomb damage, they would have been abandoned until repairs could be made, greatly decreasing the level of access to that site. Furthermore, such repairs would likely have taken place after the German bombing campaign in that area had ceased, to avoid repeat damage.
The site was occupied by peripheral open ground / wasteland, with no apparent use, which may have been neglected. ✓
The site was occupied by recreational land / sports fields which may have only experienced seasonal access.
The site was occupied by a graveyard which would have experienced limited access.
The site was occupied by agricultural land, rural countryside or woodland which would not have been accessed in full, either regularly or frequently. ✓
The site was occupied by railway sidings which may not have been as regularly checked for buckling as mainline railway tracks.
The site was occupied by soft railway embankments which are likely to have been neglected during the war.
Additional comments: n/a
9.8.4 Ground Cover
The quantity and type of ground cover present on a site during WWII would have had a significant effect, at ground level, on the visual evidence of buried UXO.
A UXB strike to dense vegetation could easily have remained undetected and during periods of frequent / heavy rainfall, very soft or even waterlogged fields could have obscured evidence of a UXB. Note that the entry hole of a 50kg UXB (the most commonly deployed German HE bomb) could have been as little as 20cm in diameter.
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If railway tracks (supported by ballast) were laid upon soft ground, the possibility cannot be entirely discounted that a UXB entry hole within these unconsolidated aggregate conditions could have been immediately in-filled by the crushed rock surrounding the hole.
Stockpiled material, such as aggregate, coal, refuse heaps, etc would also provide conditions into which a UXB might be leave little trace of its incidence.
Wartime records confirm that small German Incendiary Bombs, weighing just 1kg, were also capable of significant penetration into soil, resulting in complete burial. Furthermore, these sub-munitions (dispersed from large cluster bomb canisters) produced very small entry holes; approximately 5cm.
A UXB strike to any body of water would have been immediately obscured from view beneath the waterline. Had such an incident occurred within a tidal mudflat or river bank, the resulting entry hole will have remained only temporally, before becoming in-filled by water and sediment.
The site was partially or entirely abandoned, due to bomb damage, resulting in associated open ground likely becoming overgrown.
The site was occupied by dense, inaccessible vegetation during WWII. ✓
The site may have been susceptible to waterlogged conditions during WWII. Possibly
The site was occupied by (possibly) unmaintained grass field during WWII. ✓
The site was part occupied by a canal, river or dock basin during WWII.
The site was occupied by tidal mud or marshland during WWII.
The site was occupied by railway tracks crossing soft ground during WWII.
The site was occupied by stockpiled material during WWII.
Evidence of UXO will have been obvious at developed, yet undamaged / insignificantly damaged sites as a UXB strike to buildings or hard-surfaced ground will still have caused substantial damage or an easily identifiable and persistent entry hole, without detonating. As a result, the incident would have been reported and the UXB subsequently exhumed / removed. Similarly, although greenfield land, it is unlikely that a HE UXB entry hole on well- maintained / manicured lawns (tennis courts, bowling greens, gold course fairways / greens, gardens in affluent areas etc), would have been overlooked.
The site was occupied by buildings, hard-standing or other manmade structures that did not sustain any degree of bomb damage.
A comparison of the historical records confirms that buildings on site sustained inconsequential minor / moderate damage.
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The site was occupied by well-maintained, manicured lawn during WWII.
Any HE UXB strike to elevated risk ground cover (ruins, dense vegetation, etc) could potentially have come to rest beneath neighbouring undamaged buildings or hard- standing due to the ‘J-Curve’ Effect.
Undamaged, developed parts of the site would have been vulnerable to the J-Curve Effect.
Additional comments: n/a
9.8.5 Bomb Failure Rate Assessment:
Based on empirical evidence, it is generally accepted that 10% of the German HE bombs dropped during WWII failed to explode as designed.
Note, due to manufacturing fault or failure of the bomber crew to correctly arm their munitions, whole bomb loads often failed to detonate. Therefore, the presence of reported UXBs increases the likelihood of an additional unrecorded UXB in the vicinity.
There is no evidence to suggest that the bomb failure rate in the vicinity of the site would have been different from the “approximately 10%” figure normally ✓ used.
Additional comments: n/a
10 The Threat from Allied Military Ordnance
10.1 General
The following historical and modern facilities / activities / incidents have been considered:
• Army, Navy and RAF Bases / Installations • Military Training Areas / Weapons Ranges • Ordnance / Explosives Factories and Storage Depots • Sites requisitioned for military use • Military Fortifications and Coastal Defences • Locations of Army Explosive Ordnance Clearance Tasks • WWII Anti-Aircraft Batteries • WWII Pipe Mined Locations and Beach Minefields
The most likely source of British / Allied ordnance is anti-aircraft fire and local army activity, as discussed in the following sections.
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10.2 Potential Sources of Explosive Ordnance
10.2.1 WWII Army Activity
During WWII, the site comprised a section of the grounds of Sprowston Hall, located approximately 180m north of the site. This was requisitioned by the army for use by the Forward HQ of the Norfolk Division of Eastern Command. The site was taken over as a holding base with many types of vehicles and stores.3
Evidence states that troops from many nations were stationed at Sprowston Hall on a short- term basis. However, at one time a unit from Newfoundland were there for around a year.
A National Monument Record assessment (http://www.heritage.norfolk.gov.uk/record- details?MNF57508) has analysed a May 1944 dated photograph (taken in the weeks leading up to Operation Overlord, the invasion of France). At this time, military activity in southern England would have been at its height.
It has identified some key military features at Sprowston Hall and in the surrounding area.4 Evidence of a rifle range, practice trenches, an earthwork bank and ditch and several Nissen huts (presumably for accommodation of troops) has been noted. The site appears to have been involved with the training of troops, as these features would suggest.
The practice trenches to the south of Sprowston Hall (immediately north of the study area) were backfilled by early 1947. A further area of disturbed ground to the north of the park, less than 180m north of the site, was also visible on the photography and has been tentatively identified as a further practice trench area.
To the west of Sprowston Manor itself, less than 115m north of the site, a shooting range was visible, as an excavated ditch with semi-circular reinforced wall at its southern end, and this was filled in by 1951.
The accommodation for this site appears to have been in the form of three groups of Nissen huts, situated north-adjacent to Sprowston Hall itself. However, the most western group of huts may have had a separate function, as there are two pairs of huts surrounded by blast walls, as well as other related structures in the vicinity, and a possible slit trench located approximately 220m north of the site. A further ancillary concrete structure was visible, partially obscured by trees approximately 315m north.
To the east of the accommodation huts, a linear bank feature with intermittent ditches on either side was visible, running north-south across the field approximately 110m north of the site, as a relatively fresh-looking earthwork on the aerial photographs, and, as it was not recorded on the historic maps of the area, it seems possible that this earthwork was related to WWII activity at the site. The bank was levelled by 1947, which further suggests that it was a temporary feature relating to the WWII activity here.
The 1946 photograph presented in Annex G is of small scale / low resolution and therefore accurate analysis of small features, small structures or ground disturbance relating too previous activity cannot be made. Furthermore, as a post-war image, any evidence of WWII activity may now not be visible by this time.
3 http://www.sprowstonheritage.org.uk/Residents_Recollections_%E2%80%93_Wartime
4 http://www.heritage.norfolk.gov.uk/record-details?MNF57508
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Experience has shown that the risk of UXO contamination is highest at sites with a confirmed history of weapons training, such as Sprowston Hall. When it comes to periods of conflict and more specifically matters of surplus / unwanted ammunition during WWII, anecdotal evidence confirms an “out of sight, out of mind” culture within the British and Allied militaries. Official procedures were often ignored and unauthorised disposal of ammunition was not uncommon. Furthermore, experience has shown that the “housekeeping” of WWII soldiers was often poor with surplus, faulty or partially expended ammunition often buried, misplaced or otherwise discarded on civilian land. Therefore, it is quite possible that such activity could have occurred within the grounds of Sprowston Hall and therefore within the site boundary.
10.2.2 WWII Anti-Invasion Defence Activity
The Home Guard (HG) was a defence organisation of the British Army, operational between 1940 and 1944. It comprised 1.5 million local volunteers, otherwise ineligible for military service, and acted as a secondary defence force, in case of enemy invasion. The HG guarded the coastal areas of Britain and other important facilities such as RAF airfields, weapons factories, explosives stores, radar sites, etc. They were also very active in towns, villages and countryside within the most at-risk coastal counties.
Norfolk, situated in the east of the country, was one of the most vulnerable to attack or invasion during WWII. Consequently, the county was heavily fortified and occupied by numerous army and HG units.
The activities carried out by the HG during WWII included; road patrols, reporting on enemy airborne landings, delay the enemy at specified road-blocks, manning Observation Posts at commanding points and organising mobile fighting patrols to harry the enemy. HG patrols were issued with a variety of weapons including; rifles, shotguns, Molotov Cocktails, various grenades, Northover anti-tank Projector, Spigot mortars, Lewis machine-guns, etc.
Official records were rarely kept by the HG and therefore any present-day evidence is usually anecdotal. Anecdotal evidence suggests that members of the HG reportedly assisted in guarding the site at Sprowston Hall HG at the beginning of WWII.5 It is also well known that HG personnel often carried out anti-invasion training on requisitioned open ground. Therefore, HG activity with live ammunition is likely to have occurred within the study area during WWII.
Furthermore, HG personnel are known to have purposefully buried caches of ammunition and weapons in tactical positions, to be exhumed and used in case of invasion. This is substantiated by several recent HG UXO finds (see Annex H).
The 10th (Sprowston) Platoon formed Company No. 3 with Catton, N.E. Norwich and Barnards Works Platoons to defend the area throughout WWII. The HQ was situated on Cannerby Lane, approximately 1.6km south-west of the site and training exercises took place on Sprowston recreation ground and pavilion. Drills and manoeuvres within wooded areas, tank traps, concrete blocks, a pillbox and concertina barbed wire were reportedly used. One particular exercise involved the defence and attack of the Salhouse Road works.6
5 http://www.sprowstonheritage.org.uk/Residents_Recollections_%E2%80%93_Wartime
6 http://www.sprowstonheritage.org.uk/Local_Home_Guard
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10.2.3 Anti-Aircraft Artillery
At the start of the war two types of AAA guns were deployed: Heavy Anti-Aircraft Artillery (HAA), using large calibre weapons such as the 3.7” QF (Quick Firing) gun and Light Anti- Aircraft Artillery (LAA) using smaller calibre weapons such as 40mm Bofors gun.
During the early war period, there was a severe shortage of AAA available and older WWI 3” and modified naval 4.5” guns were deployed alongside those available 3.7” weapons. The maximum ceiling height of fire at that time was around 11,000m (for the 3.7” gun and less for other weapons). As the war progressed improved variants of the 3.7” gun were introduced and, from 1942, large 5.25 inch weapons began to be brought into service. These had significantly improved ceiling heights of fire reaching over 18,000m.
Before the war all the clockwork fuses used by the Royal Artillery had come from Switzerland. When that source of supply was cut off, Britain had been forced to make its own. After four years of war, the country still lacked the engineering skills to produce a reliable fuse.
This resulted in a considerable number of AA projectiles exploding prematurely, killing the gunners or failing to explode at all; falling to the ground as UXBs. In January 1944 more people in London were killed by HAA shells than by German bombs.
The LAA batteries were intended to engage fast low flying aircraft and were typically deployed around airfields or strategic installations. These batteries were mobile and could be moved to new positions with relative ease when required. The most numerous of these was the 40mm Bofors gun which could fire up to 120 x 40mm HE shells per minute to over 1,800m.
No permanent HAA batteries were constructed within a 5km radius of the study area during WWII, however the possibility that temporary HAA guns were also brought to this area of Norfolk during the war cannot be discounted. Anecdotal evidence suggests that an AA and searchlight battery was brought to Sprowston Hall in 1939. Additionally, temporary guns would have been brought to the two local RAF airfields, RAF Rackheath and RAF Horesham St Faith (both within 5km of the site), during WWII.
With four guns per battery firing several rounds per minute, HAA batteries could expel numerous shells in even the shortest engagements. Note, however, unexploded AA projectiles could land several kilometres from their batteries and therefore the risk of unexploded AA shell contamination cannot be entirely ruled out.
10.3 The Threat Posed by British Unexploded Ordnance
10.3.1 Land Service Ammunition (LSA)
10.3.1.1 General
The term Land Service Ammunition covers all items of ordnance that are propelled, placed or thrown during land warfare. They may be filled or charged with explosives, smoke, incendiary or pyrotechnics. They can be broken into five main groups:
a. Mortars
b. Grenades
c. Projectiles
d. Rockets
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e. Landmines
Unexploded or partially unexploded Mortars and Grenades are among the most common items of UXO encountered in the UK and therefore the possibility cannot be discounted that they were stores on site. They are commonly encountered in areas used by the military for training and are often found discarded on or near historic military bases. Examples of Grenades, Mortars and Home Guard weapons are presented in Annex I.
Items of ordnance do not become inert or lose their effectiveness with age. Time can indeed cause items to become more sensitive and less stable. This applies equally to items submerged in water or embedded in silts, clays or similar materials. The greatest risk occurs when an item of ordnance is struck or interfered with. This is likely to occur when mechanical equipment is used or when unqualified personnel pick up munitions.
10.3.1.2 Mortars
A mortar bomb is a fin-stabilised munition, normally nose-fuzed and fitted with its own propelling charge (primary cartridge). Range is increased by adding extra propellant (augmenting charges). They are either HE or Carrier and generally identified by their tear- dropped shape (older variants however are parallel sided) and a finned ‘spigot tube’ screwed or welded to the rear end of the body housing the propellant charge.
A mortar relies on a striker hitting a detonator for explosion to occur. It is possible that the striker may already be in contact with the detonator and that only a slight increase in pressure would be required for initiation. Discarded augmenting charges are often encountered around mortar firing areas/bases.
10.3.1.3 Grenades
A grenade is a short-range weapon which may be thrown by hand, fired from the end of a rifle or projected/propelled from a special purpose grenade launcher. They are divided into two categories; HE and Carrier (generally smoke). As with mortars, a grenade striker may either be in contact with the detonator or still be retained by a spring under tension, and therefore shock may cause it to function. A grenade can have an explosive range of 15-20m. Common older variants have a classic ‘pineapple’ shape; modern grenades tend to be smooth-sided.
10.3.2 Small Arms Ammunition (SAA)
The most likely type of ordnance to be encountered on site are items of SAA (bullets), especially .303” ammunition which was the standard British and Commonwealth military cartridge from 1889 until the 1950s.
However even if an item such as this functioned, the explosion would not be contained within a barrel and detonation would only result in local overpressure and very minor fragmentation from the cartridge case.
Some LAA guns and RAF fighter cannons in use with British forces during WWII utilised the 20mm round. These bullets had a small fuse and a ~4gram HE or incendiary charge. Although small, this fill quantity still has the potential to cause serious injury. Images of SAA are presented in Annex J.
10.3.3 Anti-Aircraft Shells
These shells are frequently mistakenly identified as small German air-delivered bombs, but are differentiated by the copper driving band found in front of the base. Although the larger unexploded projectiles could enter the ground they did not have great penetration ability and
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are therefore likely to be found close to WWII ground level. With a HE fill and fragmentation hazard these items of UXO also present a significant risk if encountered.
The smaller 40mm projectiles are similar in appearance and effect to small arms ammunition and, although still dangerous, present a lower risk. Pictures of AAA projectiles are presented in Annex K. Details of the most commonly deployed WWII AAA projectiles are shown below:
Gun type Calibre Shell Dimensions Shell Weight HE Fill Weight
3.7 Inch 94mm 94mm x 438mm 12.7kg 1.1kg 4.5 Inch 114mm 114mm x 578mm 24.7kg 1.7kg 40mm 40mm 40mm x 311mm 0.84kg 70g
11 Ordnance Clearance and Post-WWII Ground Works
11.1 General
The extent to which any ordnance clearance activities have taken place on site or extensive ground works have occurred is relevant since on the one hand they may indicate previous ordnance contamination but also may have reduced the risk that ordnance remains undiscovered.
11.2 EOD Bomb Disposal and Clearance Tasks
Dynasafe BACTEC holds a number of official records of explosive ordnance disposal operations during and following WWII, obtained from the Explosive Ordnance Disposal (EOD) Archive Information Office at 33 Engineer Regiment (EOD), British Army. However, no records could be found to indicate that any Army EOD tasks have taken place on site.
11.3 Post War Redevelopment
No evidence of significant post-WWII development or substantial earthworks across the study area have been found. The northern extent appears to have been cleared of dense vegetation / mature trees, and a cleared roadway has been installed in the centre. Therefore, regular agricultural activity / shallow groundworks are likely to represent the only post-war ground disturbance across the majority of the site.
12 The Overall Explosive Ordnance Threat Assessment
12.1 General Considerations
Taking into account the quality of the historical evidence, the assessment of the overall threat to any intrusive works from UXO must evaluate the following risks:
• That the site was contaminated with unexploded ordnance • That UXO remains on site • That such items could be encountered during any intrusive works • That ordnance may be activated by the works operations • The consequences of encountering or initiating ordnance
Report: 7286TA 23 Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
12.2 The Risk that the Site was Contaminated with Unexploded Ordnance
For the reasons discussed in Section 9 and 10 Dynasafe BACTEC believes that there is a risk that UXO contaminated the study area. This is based on the following:
GERMAN AIR-DELIVERED UXO
• The Rural District of St Faiths & Aylesham, within which Sprowston was historically located, was predominantly agricultural in nature and sustained a low bombing density. However, the parish of Sprowston (and the site) bordered the county borough of Norwich, which sustained a high bombing density. • Therefore, as a town on the outskirts of Norwich, the site would likely have sustained a higher bombing density than the rest of the rural district. Note, however, no viable bombing targets were present in the vicinity of the site during WWII. • Anecdotal evidence indicates that the surrounding area, including the site, were subject to tip-and-run raids. A post-WWII aerial photograph shows two bomb craters forming a stick in line with the study area, approximately 130m to the south-west of the northern extent. Therefore, the possibility that a UXB from the same bomb load struck the site cannot be discounted. • The site was located within a sparsely populated agricultural area during the war. Therefore, there is a heightened risk of a UXB falling unnoticed within the site boundary. This is especially pertinent as the heaviest German air raids on the wider Norwich area took place at night. • The majority of the study area comprised open farm land or dense vegetation during the German bombing campaign. Had a UXB fallen here, it could easily have remained undetected, since the land will not have been accessed either regularly or frequently during the Blitz. Additionally, due to its distance from any developed areas and relative lack of importance it is unlikely to have been subject to specific post-raid searches for UXO. • Furthermore, the resulting entry hole could easily have become obscured. Note, the entry hole of an SC50 UXB (the most commonly deployed German HE bombs) could have been as little as 20cm in diameter and therefore easily overlooked in dense crops, unmaintained pasture or ploughed soil.
BRITISH / ALLIED UXO
• The northern extent of the site encroaches onto the grounds of Sprowston Hall, which was requisitioned by the army during WWII for use by the Norfolk Division of Eastern Command. • Evidence obtained from external sources has indicated a number of features within the vicinity of the site regarding military activity. A rifle range, practice trenches and Nissen huts and unspecified stores (possibly ammunition related) have all been identified within a 315m radius of the site. It is therefore conceivable that surplus or unwanted ammunition may have been discarded within the grounds of Sprowston Hall, and therefore within the site boundary. Such activity has been consistently substantiated throughout England by recent ammunition finds of WWII vintage. • The 10th (Sprowston) Platoon formed the HG Company No. 3 with Catton, N.E. Norwich and Barnards Works Platoons to defend the area throughout WWII. HG units
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were reported to have assisted in guarding Sprowston Hall, and one pillbox was located approximately 140m south-west of the site. • Experience has shown that the ‘housekeeping’ of WWII soldiers was often poor with items of faulty, surplus or expended UXO often burnt, buried, misplaced or otherwise discarded on requisitioned civilian land. • No permanent HAA batteries were constructed within a 5km radius of the study area during WWII, however the possibility that temporary HAA guns were also brought to this area of Norfolk during the war cannot be discounted. Anecdotal evidence suggests that an AA and searchlight battery was brought to Sprowston Hall in 1939. Additionally, temporary guns would have been brought to the two local RAF airfields, RAF Rackheath and RAF Horesham St Faith (both within 5km of the site), during WWII. Therefore, the risk of unexploded AA shell contamination cannot be entirely ruled out.
12.3 The Risk that Unexploded Ordnance Remains on Site
The lack of significant post-WWII redevelopment, development or substantial earthworks on site suggests the risk from UXO has not been mitigated to any significant degree.
Post-war agricultural activity or shallow groundworks across the site may have mitigated the risk from very shallow buried UXO however, would not have extended deep enough to completely mitigate this risk.
12.4 The Risk that Ordnance may be Encountered during the Works
The most likely scenarios under which UXO could be encountered during construction works is during piling, drilling operations or bulk excavations. The overall risk will depend on the extent of the works, such as the numbers of boreholes/piles and the volume of the excavations.
Since an air-dropped bomb may come to rest at any depth between just below ground level and its maximum penetration depth there is also a chance that such an item could be encountered at any point below the original WWII ground level.
12.5 The Risk that Ordnance may be Initiated
The risk that UXO could be initiated if encountered will depend on its condition, how it is found and the energy with which it is struck. The most violent activity on most construction sites is percussive piling. As a result, items that are shallow buried present a slightly lower risk than those that are deep buried, since the force of impact is usually lower and they are more likely to be observed – when immediate mitigating actions can be taken.
12.6 The Consequences of Encountering or Initiating Ordnance
Clearly the consequences of an inadvertent detonation of UXO during construction operations would be catastrophic with a serious risk to life, damage to plant and a total site shutdown during follow-up investigations.
Since the risk of initiating ordnance is significantly reduced if appropriate mitigation measures are undertaken, the most important consequence of the discovery of ordnance will be economic. This would be particularly so in the case of high profile locations and could involve the evacuation of the public.
The unexpected discovery of ordnance may require the closing of the site for any time between a few hours and a week with a potentially significant cost in lost time. Note also that
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the suspected find of ordnance, if handled solely through the authorities, may also involve loss of production since the first action of the Police in most cases will be to isolate the locale whilst awaiting military assistance, even if this turns out to have been unnecessary.
12.7 Dynasafe BACTEC’s Assessment
Taking into consideration the findings of this study, Dynasafe BACTEC considers the UXO risk at the Sprowston site to be to be heterogeneous and can therefore be divided into Low and Medium Risk Zones. These are described below and illustrated on a Risk Map presented in Annex L.
Low Risk Zone:
• No sticks of German bombs in line with the site • No military activity recorded
Level of Risk
Type of Ordnance Negligible Low Medium High
German High Explosive Bombs ✓
German 1kg Incendiary Bombs ✓
British Anti-Aircraft Shells ✓
British Small Arms and Land Service Ammunition ✓
Medium Risk Zone:
• Evidence of military activity • Stick of German bombs in line with the site
Level of Risk
Type of Ordnance Negligible Low Medium High
German High Explosive Bombs ✓
German 1kg Incendiary Bombs ✓
British Anti-Aircraft Shells ✓
British Small Arms and Land Service Ammunition ✓
Report: 7286TA 26 Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
13 Proposed Risk Mitigation Strategy
13.1 General
Dynasafe BACTEC recommends the following risk mitigation measures should be deployed to support the proposed works at the Sprowston, Norwich site:
13.2 Scope Specific Risk Mitigation Measures
Both Risk Zones:
• Site Specific Explosive Ordnance Safety and Awareness Briefings to all personnel conducting intrusive works: A specialised briefing is always advisable when there is a possibility of explosive ordnance contamination. It is an essential component of the Health & Safety Plan for the site and conforms to requirements of CDM Regulations 2015. All personnel working on the site should be instructed on the identification of UXB, actions to be taken to alert site management and to keep people and equipment away from the hazard. Posters and information of a general nature on the UXB threat should be held in the site office for reference and as a reminder.
• The Provision of Unexploded Ordnance Site Safety Instructions: These written instructions contain information detailing actions to be taken in the event that unexploded ordnance is discovered. They are to be retained on site and will both assist in making a preliminary assessment of a suspect object and provide guidance on the immediate steps to be taken in the event that ordnance is believed to have been found.
Medium Risk Zone only:
• Non-Intrusive Magnetometer Survey and Target Investigation (greenfield land only): This survey is carried out using caesium vapour magnetometers linked to a data logger. Data is interpreted using advanced proprietary software which is capable of modelling the magnetic anomalies for mass, depth and location, thus providing information which can be used to locate discrete buried objects that may be ordnance. The system will typically locate buried ordnance to a depth of 4m for a 50kg bomb (the smallest HE bomb used by the Luftwaffe) and deeper for larger bombs. Additionally, the survey will locate any buried services with a magnetic signature, will indicate areas of gross magnetic “contamination” (which may indicate unknown underground obstructions) and provide information on archaeological features.
• Explosive Ordnance Disposal (EOD) Engineer presence on site to support shallow excavations (brownfield alternative to a Non-Intrusive Survey): When on site the role of the EOD Engineer would include; monitoring works using visual recognition and instrumentation and immediate response to reports of suspicious objects or suspected items of ordnance that have been recovered by the ground workers on site; providing Explosive Ordnance Safety and Awareness briefings to any staff that have not received them earlier and advise staff of the need to modify working practices to take account of the ordnance threat, and finally to aid Incident Management which would involve liaison with the local authorities and Police should ordnance be identified and present an explosive hazard.
• Intrusive Magnetometer Survey of any pile locations deeper than 4m bgl, down to the maximum bomb penetration depth: Dynasafe BACTEC can deploy a range of intrusive magnetometry techniques to clear ahead of all the pile locations. The appropriate technique is governed by a number of factors, but most importantly the site’s ground conditions. The appropriate survey methodology would be confirmed once the enabling works have been completed. A site meeting would be required between BACTEC and the client to determine the methodology suitable for this site. Target investigation or avoidance will be recommended as appropriate.
Should the planned works be modified or additional intrusive engineering works be considered, Dynasafe BACTEC should be consulted to see if re-assessment of the risk or mitigation recommendations is necessary. Dynasafe BACTEC Limited 5th September 2017
Report: 7286TA 27 Dynasafe BACTEC Limited Delta Simons Sprowston, Norwich
Bibliography
The key sources consulted during this assessment are listed below;
Bates, H, E., Flying Bombs over England, Frogletts Publications Ltd. 1994.
Bowyer, M. J. F., Air Raid! The Enemy Air Offensive against East Anglia 1939-45, P. Stephens. 1986.
Dobinson, C., AA Command: Britain’s Anti-Aircraft Defences of the Second World War, Methuen. 2001.
Fegan, T., The Baby Killers’: German Air raids on Britain in the First World War, Leo Cooper Ltd. 2002.
Fleischer, W., German Air-Dropped Weapons to 1945, Midland Publishing. 2004.
Jappy, M. J., Danger UXB: The Remarkable Story of the Disposal of Unexploded Bombs during the Second World War. Channel 4 Books, 2001.
Price, A., Blitz on Britain, The Bomber Attacks on the United Kingdom 1939 – 1945, Purnell Book Services Ltd. 1977.
Ramsey, W., The Blitz Then and Now, Volume 1, Battle of Britain Prints International Limited. 1987.
Ramsey, W., The Blitz Then and Now, Volume 2, Battle of Britain Prints International Limited. 1988.
Ramsey, W., The Blitz Then and Now, Volume 3, Battle of Britain Prints International Limited. 1990.
Whiting, C., Britain Under Fire: The Bombing of Britain’s Cities 1940-1945, Pen & Sword Books Ltd. 1999.
Report: 7286TA 28 Dynasafe BACTEC Limited Site Location Maps Annex A
North
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: © Crown copyright. All rights reserved. Licence number AL100033639 Recent Aerial Photograph Annex B
North
Approximate site boundary
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Google Earth TM Mapping Services Site Plan Annex C
North
Site boundary
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Google Earth TM Mapping Services 1938 OS Map Annex D-1
North
Approximate site boundary
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Landmark Maps 1950 OS Map Annex D-2
North
Approximate site boundary
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Landmark Maps German Air-Delivered Ordnance Annex Most Commonly Deployed German Bombs E
SC 50
Bomb Weight: 40-54kg (110-119lb) Explosive Weight: c25kg (55lb) Fuze Type: Impact fuze/electro- mechanical time delay fuze Bomb Dimensions: 1,090 x 280mm (42.9 x 11.0in) Body Diameter: 200mm (7.87in) Use: Against lightly damageable materials, hangars, railway rolling stock, ammunition depots, light bridges and buildings up to three stories. 50kg bomb, London Docklands Remarks: The smallest and most common conventional German 400mm bomb. Nearly 70% of bombs dropped on the UK were 50kg.
Minus tail section
SC 250
Bomb weight: 245-256kg (540-564lb) Explosive weight: 125-130kg (276-287lb) Fuze type: Electrical impact/mechanical time delay fuze. Bomb dimensions: 1640 x 512mm (64.57 x 20.16in) Body diameter: 368mm (14.5in) Use: Against railway installations, embankments, flyovers, underpasses, large buildings and below-ground installations.
250kg bomb, Hawkinge
1kg Incendiary Bomb 1 2 3
Bomb weight: 1.0 and 1.3kg (2.2 and 2.87lb) Filling: 680gm (1.3lb) Thermite Fuze type: Impact fuze Bomb dimensions: 350 x 50mm (13.8 x 1.97in) Body diameter: 50mm (1.97in) Use: As incendiary – dropped in clusters against towns and industrial complexes Remarks: Jettisoned from air-dropped containers. Magnesium alloy case. Sometimes fitted with high explosive charge
1. Scaffold pipe 2. Incendiary 1kg bomb 3. Incendiary bomb recently found on site in UK
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources UXO Press Articles - Recent UK Finds Annex F-1
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Various News Sources UXO Press Articles – Fatal Incidents at Annex Construction Sites F-2
1994 2008
2006
2010 2006
Top Left: WWII bomb killed 3 and injured 8 in Berlin – 1994. Middle Left: WWII bomb killed 3 in Goettingen, Germany – 2010. Bottom Left: Excavator operator killed by WWII bomb in Euskirchen, Germany – 2014. Top Right: WWII bomb injures 17 at construction site in Hattingen, Germany - 2008. Middle Right: A highway construction worker in Germany accidentally struck a WWII bomb, killing himself and wrecking several passing cars - 2006. Bottom Right: Destroyed piling rig and dump truck after 2014 detonation of WWII UXB in Austria - 2006.
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Various News Sources RAF Aerial Photography – 1946 Annex G
North
Approximate site boundary Likely HE bomb craters
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Norfolk County Council Recent UXO Incidents - Home Guard Annex Incendiary Grenades H
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Various news sources Annex Land Service Ammunition Grenades I-1
No. 36 ‘Mills’ Grenade
Weight: 0.7kg filled (1lb 6oz) Type: Hand or discharger, fragmentation Dimensions: 95 x 61mm (3.7 x 2.4in) Filling: Alumatol, Amatol 2 or TNT Remarks: 4 second hand- throwing fuse with approximate 30m range. First introduced May 1918.
No. 69 Grenade
Weight: 0.38kg filled (0.8lb) Type: Percussion/Blast Date Introduced: December 1940 Remarks: Black Bakelite body. Blast rather than fragmentation type. After unscrewing the safety cap, a tape is held when throwing the grenade releasing the safety bolt in the throwing motion. Detection is problematic due to its very low metal content.
Typical Smoke Grenade
Dimensions: Approx. 65 x 115mm (2.5 x 4.5in) Type: Smoke Date Introduced: Current MoD issue Remarks: Smoke grenades are used as ground-to-ground or ground- to-air signalling devices, target or landing zone marking devices, and screening devices for unit movement.
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources Annex Land Service Ammunition Mortars I-2
Typical 2 inch High Explosive Mortar
Bomb Weight: 1.02kg (2.25lb) Type: High Explosive Dimensions: 51 x 290mm (2in x 11.4in) Filling: 200g RDX/TNT Maximum Range: 457m (500yds) Remarks: Fitted with an impact fuze which detonates the fuze booster charge (exploder) and, in turn, the high explosive charge. The main charge shatters the mortar bomb body, producing near optimum fragmentation and blast effect at the target.
Typical 3 inch Smoke Mortar
Type: Smoke Dimensions: c490 x 76mm (19.3in x 3in) Filling: Typically white phosphorous Maximum Range: 2515m (2,750yds) Remarks: On impact, the fuze functions and initiates the bursting charge. The bursting charge ruptures the mortar bomb body and disperses the white phosphorous filler. The white phosphorous produces smoke upon exposure to the air.
Typical 2 inch Illuminating Mortar
Type: Illum. Dimensions: 51 x 290mm Filling: Various Remarks: The expulsion charge ignites and ejects the candle assembly. A spring ejects the parachute from the tail cone. The parachute opens, slowing the descent of the burning candle which illuminates the target.
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources Annex Land Service Ammunition Home Guard I-3
Self Igniting Phosphorous (SIP) Grenades
Filling: White Phosphorous and Benzene Remarks: The grenade comprised a glass bottle with a total volume of approximately one pint. It was filled with White Phosphorus, benzene, a piece of rubber and water. Over time the rubber dissolved to create a sticky fluid which would self ignite when the bottle broke. Fired by hand or Northover Projector. Sometimes called the “A & W” (Albright & Wilson) grenade.
No 74 Grenade (Sticky Bomb)
Remarks: Designed as an anti-tank grenade and used by the Home Guard. The grenade consisted of a glass ball on the end of a Bakelite (plastic) handle. Inside the glass ball was an explosive filling whilst on the outside was a very sticky adhesive covering. Until used, this adhesive covering was encased in a metal outer casing.
Flame Fougasse Bomb
Remarks: A Flame Fougasse was a weapon in which the projectile was a flammable liquid, typically a mixture of petrol and oil. It was usually constructed from a 40- gallon drum dug into the roadside and camouflaged. Ammonal provided the propellant charge which, when triggered, caused the weapon to shoot a flame 3m (10ft) wide and 27m (30 yards) long. Initially a mixture of 40% petrol and 60% gas oil was used, this was later replaced by an adhesive gel of tar, lime and petrol known as 5B.
www.pillbox-study-group.org.uk
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources Annex Small Arms Ammunition J
20mm Hispano HEI Ammunition
Type: Live canon round Markings: Upper half of projectile painted ‘buff’ colour, lower half is red. Cartridge Weight: 256 grams Dimensions: Total cartridge / projectile length - 182mm Fuzed: Contact fuze – No.253, No.254 or No.917 Filling: 108 grains of contact explosive + 68 grains of SR.379 incendiary composition. Threat: Explosives within unspent cartridge as well as the projectile. Deployment: Royal Navy, RAF and British Army Light Anti- Aircraft guns. Also RAF aircraft canons. Remarks: Cartridges are belted or supplied lose in cartons.
.303” Ammunition
Type: Rifle / machine gun round Markings: Regular round - none. Tracer round – red Primer Bullet Weight: 150 - 180 grams Dimensions: Total cartridge /projectile length - 78mm Filling: Regular round – none. Tracer round - small incendiary fill Threat: Explosive cordite within unspent cartridge Deployment: Royal Navy, RAF and British Army Light Anti- Aircraft guns, machine guns and rifles. Standard British and Commonwealth military cartridge from 1889 until the 1950s. Remarks: Cartridges are belted or supplied lose in cartons.
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources Anti-Aircraft Artillery Annex Anti-Aircraft Projectiles K
3.7 inch Anti-Aircraft Projectile
Weight: 12.7kg (28lb) Dimensions: 94 x 360mm (3.7 x 14.7in) Carriage: Mobile and Static Versions Rate of Fire: 10-20 rounds per minute Ceiling: 9-18,000m (29-59,000ft) Muzzle Velocity: 792m/s (2,598ft/s) Remarks: 4.5 inch projectiles were also This AA shell was uncovered on a construction site in North commonly utilised London in February 2009.
Layout plan for a typical HAA battery site. 3.7 inch AA Projectile Minus Fuze Hyde Park 1939 3.7 Inch QF gun on mobile mounting Rockets / Unrotating Projectiles
Weight: Overall: 24.5kg (54lb) Warhead: 1.94kg (4.28lb) Dimensions: 1930mm x 82.6mm (76 x 3.25in) Carriage: Mobile – transported on trailers Ceiling: 6770m (22,200ft) Maximum Velocity: 457mps (1,500 fps)
MK II HE Shell (3.5kg) Rocket Battery in action Home Guard soldiers load an anti-aircraft rocket at a 'Z' Battery 2” U.P AA Rocket
40mm Bofors Gun Projectile
Weight: 0.86kg (1.96lb) Dimensions: 40mm x 310mm (1.6in x 12.2in) Rate of Fire: 120 rounds per minute Ceiling: 23,000ft (7000m ) Muzzle Velocity: 2,890 ft/s (881m/s) Remarks: Mobile batteries – normally few records of where these guns were located
40mm Bofors gun and crew at Stanmore in Middlesex, 28 June 1940.
Unexploded 40mm Bofors projectile
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited and various historical sources Risk Map Annex L
North Note: image for information only
Approximate site boundary
Low Risk Zone Medium Risk Zone
• No sticks of German bombs in line with the site • Evidence of military activity • No military activity recorded • Stick of German bombs in line with the site
Recommended Risk Mitigation Measures:
Medium Risk Zones only:
• Explosive Ordnance Disposal (EOD) Engineer presence on site to support shallow investigations.
• Non-Intrusive Magnetometer Survey and Target Investigation (greenfield land only)
• Intrusive Magnetometer Survey of all pile locations deeper than 4m bgl, down to the maximum bomb penetration depth
Both Risk Zones:
• Site Specific Explosive Ordnance Safety and Awareness Briefings to all personnel conducting intrusive works within both Risk Zones
• The Provision of Unexploded Ordnance Site Safety Instructions
Report Reference: Client: Delta Simons 7286TA Project: Sprowston, Norwich
Source: Dynasafe BACTEC Limited
Appendix D – Borehole Logs & SPT Calibrations Certificate
Environment | Health & Safety | Sustainability Project No: Hole ID: Page: Head Office 17-0337.02 CP201 3 Henley Way, Doddington Road 1 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Cable Percussive Borehole Log 05/09/2017 Persimmon Homes and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Dark brown slightly sandy silt with rare gravel of fine to medium subrounded to subangular flint and one fragment of (0.40) 0.20 ES 1 ceramic. Sand is medium. (TOPSOIL). 0.40 27.39 Orangish brown slightly clayey silty fine to medium SAND with rare gravel of fine to 0.50 - B 1 medium subrounded to rounded flint. 0.90 (SHERRINGHAM CLIFFS FORMATION) 0.80 ES 2 (1.00) 1.00 D 1
1.40 26.39 Medium-dense orangish brown sandy GRAVEL of fine to medium subangular to 1.50 - B 2 1.50 SPT(C)N=22 subrounded flint. Sand is medium to coarse. 1.95 (2,3/4,5,6,7) (SHERRINGHAM CLIFFS FORMATION)
(1.70)
2.50 - B 3 2.50 SPT(C)N=22 2.95 (1,3/4,5,6,7)
3.10 24.69 3.10 D 1 Firm orangish brown slightly sandy CLAY 3.10 D 2 with occasional gravel of fine subangular to (0.30) subrounded flint. 3.40 24.39 (HAPPISBURGH GLACIGENIC FORMATION) 3.50 - D 3 3.50 SPT(S)N=10 Medium-dense, becoming loose at 4.50 m 3.95 (1,1/2,2,3,3) bgl, orangish brown slightly clayey slightly gravelly silty fine to medium SAND. Gravel is fine to medium subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
(1.80)
4.50 - D 4 4.50 SPT(S)N=8 4.95 (1,0/1,1,2,4)
5.20 22.59 Very dense, becoming dense at 7.50 m bgl, light yellowish brown gravelly medium to coarse SAND. Gravel is fine to medium subangular to subrounded flint. 5.50 - B 4 5.50 SPT(C)N=50 (HAPPISBURGH GLACIGENIC 5.95 (3,5/50 for FORMATION) 255mm)
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Groundwater Date Time Strike Duration Standing Depth (m) Time (h:m) encountered at 7.50 m bgl. 5. Borehole completed at 10.00 m bgl due to required depth 7.50 m 20 min 6.00 m being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E625866.68 N312412.61 27.79 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 CP201 3 Henley Way, Doddington Road 2 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Cable Percussive Borehole Log 05/09/2017 Persimmon Homes and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Very dense, becoming dense at 7.50 m bgl, light yellowish brown gravelly medium to coarse SAND. Gravel is fine to medium 6.00 subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
7.00 - B 5 7.00 SPT(C)N=41 7.45 (4,6/41 for 265mm)
7.50
(4.60)
8.50 - B 6 8.50 SPT(C)N=31 8.95 (1,3/5,7,9,10)
9.80 17.99 9.80 D 2 Firm orangish brown mottled grey slightly (0.20) sandy CLAY with occasional gravel of fine 10.00 17.79 150 to medium subrounded to rounded flint. 10.00 D 5 (HAPPISBURGH GLACIGENIC FORMATION) Borehole complete at 10.00 m bgl.
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Groundwater Date Time Strike Duration Standing Depth (m) Time (h:m) encountered at 7.50 m bgl. 5. Borehole completed at 10.00 m bgl due to required depth 7.50 m 20 min 6.00 m being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E625866.68 N312412.61 27.79 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 CP202 3 Henley Way, Doddington Road 1 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of Taylor Wimpey, Date: 04/09/2017 - Client: Cable Percussive Borehole Log Persimmon Homes 05/09/2017 and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Dark brown slightly sandy silt with rare gravel of fine to medium subrounded to (0.30) subangular flint. Sand is medium. 0.30 23.88 0.25 ES 1 (TOPSOIL). Orangish brown fine to medium SAND with occasional gravel of fine to medium (0.45) 0.50 D 1 subangular to subrounded flint. 0.50 ES 2 (HAPPISBURGH GLACIGENIC FORMATION) 0.75 23.43 Yellowish orange very sandy GRAVEL of fine to coarse subangular to subrounded flint. Sand is medium. 1.00 D 2 (HAPPISBURGH GLACIGENIC (0.55) FORMATION) 1.30 22.88 Firm to stiff orangish brown slightly sandy CLAY with occasional gravel of fine to medium subrounded to rounded flint. Sand 1.50 D 1 1.50 SPT(C)N=18 is medium. 1.50 - B 1 (1,2/3,4,5,6) (HAPPISBURGH GLACIGENIC 1.95 FORMATION)
(1.70)
2.50 - B 2 2.50 SPT(C)N=29 2.95 (3,4/5,7,8,9)
3.00 21.18 3.00 D 3 Very dense light brown silty fine to medium SAND with occasional gravel of fine subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION) (0.70) 3.50 - D 4 3.50 SPT(S)N=50 3.95 (1,3/50 for 3.70 20.48 295mm) Dense, becoming medium-dense from 5.50 m bgl, orangish brown sandy GRAVEL of fine to medium subangular to subrounded flint. Sand is medium to coarse. (HAPPISBURGH GLACIGENIC FORMATION) 4.30
4.50 - B 3 4.50 SPT(C)N=39 4.95 (2,5/6,9,10,14) (2.30)
5.50 - B 4 5.50 SPT(C)N=18 5.95 (1,2/3,4,5,6)
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Groundwater Date Time Strike Duration Standing Depth (m) Time (h:m) encountered at 6.00 m bgl. 5. Borehole completed at 10.00 m bgl due to required depth 6.00 m 20 min 4.30 m being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E626529.58 N312283.35 24.18 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 CP202 3 Henley Way, Doddington Road 2 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of Taylor Wimpey, Date: 04/09/2017 - Client: Cable Percussive Borehole Log Persimmon Homes 05/09/2017 and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Dense, becoming medium-dense from 5.50 m bgl, orangish brown sandy GRAVEL of fine to medium subangular to subrounded 6.00 18.18 6.00 flint. Sand is medium to coarse. (HAPPISBURGH GLACIGENIC FORMATION) Medium-dense orangish brown SAND and GRAVEL. Sand is medium to coarse. Gravel is fine to medium subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
7.00 - B 5 7.00 SPT(C)N=24 7.45 (1,3/5,6,6,7)
(3.50)
8.50 - B 6 8.50 SPT(C)N=29 8.95 (2,3/6,7,8,8)
9.50 14.68 9.50 - B 7 Medium-dense greyish brown medium 10.00 SAND with occasional gravel of fine to medium subangular to subrounded flint and shell fragments. (HAPPISBURGH GLACIGENIC 150 FORMATION) (0.95) 10.00 SPT(C)N=24 (1,3/3,5,7,9)
10.45 13.73 Borehole complete at 10.45 m bgl.
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Groundwater Date Time Strike Duration Standing Depth (m) Time (h:m) encountered at 6.00 m bgl. 5. Borehole completed at 10.00 m bgl due to required depth 6.00 m 20 min 4.30 m being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E626529.58 N312283.35 24.18 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 CP203 3 Henley Way, Doddington Road 1 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Cable Percussive Borehole Log 04/09/2017 Persimmon Homes and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Dark brown slightly sandy slightly gravelly silt. Sand is fine to medium. Gravel is fine to medium subangular flint. (TOPSOIL). (0.40) 0.20 ES 1 0.40 32.74 Very dense orangish brown slightly gravelly fine to medium SAND, becoming gravelly 0.50 D 1 from 1.00 m bgl. Gravel is fine to medium 0.60 ES 1 subangular to subrounded flint. 0.60 - B 2 (SHERRINGHAM CLIFFS FORMATION) 1.00
(1.60)
1.50 - B 2 1.50 SPT(C)50 (6,18/50 1.95 for 125mm)
2.00 31.14 2.00 D 2 Loose orangish brown slightly sandy GRAVEL of fine subangular to subrounded flint. Sand is coarse. (SHERRINGHAM CLIFFS FORMATION)
(1.00) 2.50 SPT(C)N=9 (2,1/2,1,3,3)
3.00 30.14 150 3.00 D 3 Medium-dense, locally loose from 4.50 m bgl to 7.00 m bgl, orangish brown slightly clayey slightly silty fine to medium SAND with rare gravel of fine to medium subangular to subrounded flint. (SHERRINGHAM CLIFFS FORMATION) 3.50 - D 4 3.50 SPT(S)N=10 3.95 (1,2/2,2,3,3)
4.50 - B 3 4.50 SPT(S)N=6 4.95 (1,0/1,1,2,2)
5.50 - D 5 5.50 SPT(S)N=8 5.95 (1,2/1,2,2,3)
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Borehole Date Time Strike Duration Standing Depth (m) Time (h:m) remained dry upon completion. 5. Borehole completed at 10.00 m bgl due to required depth being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E626913.50 N311499.87 33.14 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 CP203 3 Henley Way, Doddington Road 2 of 2 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Cable Percussive Borehole Log 04/09/2017 Persimmon Homes and Hopkins Sample Details Test Details Strata Strata Reduced Casing Homes Description of Strata Legend Depth Thickness Level Diameter Water Backfill Depth Depth (m bgl) (m) (mAOD) (mm) Type Ref Results (m) (m) Medium-dense, locally loose from 4.50 m bgl to 7.00 m bgl, orangish brown slightly clayey slightly silty fine to medium SAND with rare gravel of fine to medium subangular to subrounded flint. (SHERRINGHAM CLIFFS FORMATION)
6.50 D 6
7.00 - D 7 7.00 SPT(S)N=12 7.45 (2,2/3,3,3,3)
(7.00) 8.00 D 8
8.50 - D 9 8.50 SPT(S)N=12 8.95 (2,2/3,3,3,3)
10.00 23.14 10.00 D 1 10.00 SPT(S)N=18 Stiff dark brown slightly sandy CLAY with 10.00 - D 10 (1,2/3,4,5,6) rare gravel of fine subangular flint. 10.45 (HAPPISBURGH GLACIGENIC (0.45) FORMATION) 10.45 22.69 Borehole complete at 10.45 m bgl.
Remarks: Water Stike Water Level Chiselling 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Borehole Date Time Strike Duration Standing Depth (m) Time (h:m) remained dry upon completion. 5. Borehole completed at 10.00 m bgl due to required depth being achieved. 6. Borehole installed with a 50 mm HDPE standpipe to 10.00 m bgl with gas bung and lockable tophat cover.
Coordinates: Elevation (mAOD): Drilled By: Plant Used: Logged: Checked: Approved: Scale (m): E626913.50 N311499.87 33.14 SI Drilling Dando 2000 GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP201 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy slightly gravelly silt. Sand is fine to medium. Gravel is fine to medium subangular flint. 0.10 ES 1 (TOPSOIL). 0.40 26.74 Dark orangish brown very gravelly medium to coarse SAND. Gravel is fine to coarse subangular to subrounded flint. (SHERRINGHAM CLIFFS FORMATION) 0.70 ES 2
1.00 26.14 Orangish brown slightly clayey slightly silty gravelly medium to coarse SAND. Gravel is fine to medium subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
1.50 B 1
2.20 24.94 Yellowish orange slightly clayey slightly gravelly silty SAND. Gravel is fine to medium subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
3.00 24.14 Trial pit complete at 3.00 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Excavation remained dry upon completion. 5. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626170.13 N312285.67 27.14 GB Digger Hire JCB 3CX GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP202 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy slightly gravelly silt. Sand is fine to medium. Gravel is fine to medium subangular flint. (TOPSOIL). 0.20 ES 1
0.45 22.35 Orangish brown SAND and GRAVEL. Sand is medium to 0.50 ES 2 coarse. Gravel is fine to medium angular to subangular flint. (SHERRINGHAM CLIFFS FORMATION)
1.20 21.60 1.20 B 1 Orange slightly clayey slightly gravelly fine to medium SAND, becoming gravelly from 1.80 m bgl. Gravel is fine to coarse angular to subangular flint. (HAPPISBURGH GLACIGENIC FORMATION)
2.00 20.80 Light yellowish brown slightly clayey slightly gravelly medium to coarse SAND. Gravel is fine to medium subangular to subrounded flint. 2.20 B 2 (HAPPISBURGH GLACIGENIC FORMATION)
3.20 19.60 Trial pit complete at 3.20 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Excavation remained dry upon completion. 5. Trial pit unstable below 2.00 m bgl. 6. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626452.81 N312416.00 22.80 GB Digger Hire JCB 3CX GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP203 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy silt with occasional gravel of fine to medium subangular to subrounded flint. Sand is fine to medium. (TOPSOIL). 0.30 ES 1 0.40 25.86 Orange gravelly silty medium to coarse SAND. Gravel is fine to coarse subrounded to angular flint. (HAPPISBURGH GLACIGENIC FORMATION) 0.60 ES 2
0.80 B 1
1.00 25.26 Orangish brown slightly clayey fine to medium SAND with occasional gravel of fine to coarse subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
2.00 24.26 Yellow slightly gravelly fine to medium SAND. Gravel is fine to medium subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
2.50 B 2
3.00 23.26 Trial pit complete at 3.00 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Excavation remained dry upon completion. 5. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626377.68 N312211.94 26.26 GB Digger Hire JCB 3CX GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP204 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy slightly gravelly silt. Sand is medium. Gravel is fine to coarse subangular to rounded flint. 0.10 ES 1 (TOPSOIL). 0.40 28.67 Orange silty fine to medium SAND with occasional gravel of fine to medium subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION) 0.60 ES 2
1.00 28.07 1.00 B 1 Light greyish brown slightly clayey silty fine to medium SAND with occasional gravel of fine to coarse subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION)
2.00 B 2
2.90 26.17 Light brown gravelly medium to coarse SAND. Gravel is fine to 3.00 26.07 medium subrounded to rounded flint. (HAPPISBURGH GLACIGENIC FORMATION) Trial pit complete at 3.00 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Excavation remained dry upon completion. 5. Trial pit unstable below 1.50 m bgl. 6. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626511.05 N312002.69 29.07 GB Digger Hire JCB 3CX GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP205 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy silt with frequent gravel of fine to coarse subangular to subrounded flint. Sand is medium. (TOPSOIL). 0.20 ES 1 0.40 27.21 Orange slightly clayey slightly gravelly fine to medium SAND. Gravel is fine to medium subangular to subrounded flint. 0.50 B 1 (HAPPISBURGH GLACIGENIC FORMATION) 0.50 ES 2
1.00 26.61 Firm orangish brown slightly sandy CLAY with occasional gravel of fine to coarse subangular to subrounded flint. (HAPPISBURGH GLACIGENIC FORMATION) 1.20 D 1
2.00 B 2 2.00 HV= 42 kPa 2.00 HV= 50 kPa 2.00 HV= 55 kPa
3.00 24.61 3.00 Trial pit complete at 3.00 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Groundwater encountered at 3.00 m bgl. 5. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626637.38 N311894.46 27.61 GB Digger Hire JCB 3CX GT TH DW 1:30 Project No: Hole ID: Page: Head Office 17-0337.02 TP206 3 Henley Way, Doddington Road 1 of 1 Lincoln, LN6 3QR Project: Tel: +44 (0) 1522 882555 Email: [email protected] Phase 2 - GT20, Sprowston Consortium of
Date: Client: Taylor Wimpey, Trial Pit Log 05/09/2017 Persimmon Homes and Hopkins Strata Reduced Water Sample Details HomesTest Details Description of Strata Legend Depth Level Strike Depth Depth (m) (mAOD) (m) Type Ref Results (m) (m) Dark brown slightly sandy slightly gravelly silt. Sand is medium. Gravel is fine to medium subangular to rounded flint. 0.10 ES 1 (TOPSOIL). 0.40 30.26 0.40 ES 2 Yellowish orangish brown gravelly fine to medium SAND. Gravel is fine to coarse subangular to subrounded flint. (SHERRINGHAM CLIFFS FORMATION)
1.00 B 1
3.00 27.66 Trial pit complete at 3.00 m bgl.
Dimensions and Orientation: Remarks: Length = 2.10 m Orientation: 1. Engineer verified logged in general accordance to BS 5930:2015. 2. Area CAT scanned prior to excavation. 3. Elevation/location data obtained from GPS survey. 4. Excavation remained dry upon completion. 5. Excavation backfilled with arising. Width = 0.60 m Inclination:
Coordinates: Elevation (mAOD): Excavated By: Plant Used: Logged: Checked: Approved: Scale: E626831.52 N311677.40 30.66 GB Digger Hire JCB 3CX GT TH DW 1:30
Appendix E – Geotechnical Analysis Results
Environment | Health & Safety | Sustainability
Appendix F – Soil Chemical Analysis Results
Environment | Health & Safety | Sustainability Chemtest Ltd. Depot Road Newmarket CB8 0AL Tel: 01638 606070 Email: [email protected] Final Report
Report No.: 17-23685-1
Initial Date of Issue: 14-Sep-2017
Client Delta Simons
Client Address: 3 Henley Office Park Doddington Road Lincoln Lincolnshire LN6 3QR
Contact(s): Tom Horner Gemma Tatton
Project 17-0337.02 - Sprowston
Quotation No.: Date Received: 08-Sep-2017
Order No.: DS34488 Date Instructed: 08-Sep-2017
No. of Samples: 18
Turnaround (Wkdays): 5 Results Due: 14-Sep-2017
Date Approved: 14-Sep-2017
Approved By:
Details: Glynn Harvey, Laboratory Manager
Page 1 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508489 508490 508491 508492 508493 508494 508495 508496 508497 Order No.: DS34488 Client Sample Ref.: CP201 CP201 CP202 CP202 CP203 CP203 TP201 TP201 TP202 Client Sample ID.: ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.20 0.80 0.25 0.50 0.20 0.60 0.10 0.70 0.20 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD ACM Type U 2192 N/A ------No Asbestos No Asbestos No Asbestos No Asbestos No Asbestos No Asbestos Asbestos Identification U 2192 % 0.001 Detected Detected Detected Detected Detected Detected Moisture N 2030 % 0.020 10 6.6 14 4.6 13 6.5 11 5.5 12 Soil Colour N 2040 N/A Brown Brown Brown Brown Brown Brown Brown Brown Brown Other Material N 2040 N/A Stones Stones Stones Stones Stones Stones Stones Stones Stones Soil Texture N 2040 N/A Sand Sand Sand Sand Sand Sand Sand Sand Sand pH M 2010 N/A 7.1 7.9 7.2 7.8 7.3 7.7 Boron (Hot Water Soluble) M 2120 mg/kg 0.40 < 0.40 0.43 < 0.40 < 0.40 0.53 < 0.40 Sulphate (2:1 Water Soluble) as SO4 M 2120 g/l 0.010 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 < 0.010 Arsenic M 2450 mg/kg 1.0 8.6 8.6 6.9 8.9 9.6 11 Cadmium M 2450 mg/kg 0.10 0.15 < 0.10 0.20 < 0.10 0.16 0.16 Chromium M 2450 mg/kg 1.0 12 19 12 13 12 13 Copper M 2450 mg/kg 0.50 16 6.2 15 5.8 23 21 Mercury M 2450 mg/kg 0.10 0.17 < 0.10 < 0.10 < 0.10 0.22 0.16 Nickel M 2450 mg/kg 0.50 8.1 12 7.7 5.6 8.8 8.1 Lead M 2450 mg/kg 0.50 51 11 49 21 78 60 Selenium M 2450 mg/kg 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 < 0.20 Zinc M 2450 mg/kg 0.50 31 29 590 18 39 45 Chromium (Hexavalent) N 2490 mg/kg 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 < 0.50 Total TPH >C6-C40 M 2670 mg/kg 10 < 10 < 10 < 10 21 Aliphatic TPH >C5-C6 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C6-C8 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C8-C10 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C10-C12 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C12-C16 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C16-C21 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C21-C35 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C35-C44 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Total Aliphatic Hydrocarbons N 2680 mg/kg 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 Aromatic TPH >C5-C7 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C7-C8 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C8-C10 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C10-C12 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C12-C16 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C16-C21 U 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C21-C35 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C35-C44 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Page 2 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508489 508490 508491 508492 508493 508494 508495 508496 508497 Order No.: DS34488 Client Sample Ref.: CP201 CP201 CP202 CP202 CP203 CP203 TP201 TP201 TP202 Client Sample ID.: ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.20 0.80 0.25 0.50 0.20 0.60 0.10 0.70 0.20 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD Total Aromatic Hydrocarbons N 2680 mg/kg 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 Total Petroleum Hydrocarbons N 2680 mg/kg 10.0 < 10 < 10 < 10 < 10 < 10 Naphthalene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Acenaphthylene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Acenaphthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Fluorene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Phenanthrene M 2700 mg/kg 0.10 0.51 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Fluoranthene M 2700 mg/kg 0.10 1.3 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Pyrene M 2700 mg/kg 0.10 1.4 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Chrysene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[b]fluoranthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[k]fluoranthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]pyrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Indeno(1,2,3-c,d)Pyrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Dibenz(a,h)Anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[g,h,i]perylene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Total Of 16 PAH's M 2700 mg/kg 2.0 3.2 < 2.0 < 2.0 < 2.0 < 2.0 < 2.0 Demeton-O N 2820 mg/kg 0.20 < 0.20 Phorate N 2820 mg/kg 0.20 < 0.20 Demeton-S N 2820 mg/kg 0.20 < 0.20 Disulfoton N 2820 mg/kg 0.20 < 0.20 Fenthion N 2820 mg/kg 0.20 < 0.20 Trichloronate N 2820 mg/kg 0.20 < 0.20 Prothiofos N 2820 mg/kg 0.20 < 0.20 Fensulphothion N 2820 mg/kg 0.20 < 0.20 Sulprofos N 2820 mg/kg 0.20 < 0.20 Azinphos-Methyl N 2820 mg/kg 0.20 < 0.20 Coumaphos N 2820 mg/kg 0.20 < 0.20 Alpha-HCH N 2840 mg/kg 0.20 < 0.20 Gamma-HCH (Lindane) N 2840 mg/kg 0.20 < 0.20 Beta-HCH N 2840 mg/kg 0.20 < 0.20 Delta-HCH N 2840 mg/kg 0.20 < 0.20 Heptachlor N 2840 mg/kg 0.20 < 0.20 Aldrin N 2840 mg/kg 0.20 < 0.20 Heptachlor Epoxide N 2840 mg/kg 0.20 < 0.20 Gamma-Chlordane N 2840 mg/kg 0.20 < 0.20 Page 3 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508489 508490 508491 508492 508493 508494 508495 508496 508497 Order No.: DS34488 Client Sample Ref.: CP201 CP201 CP202 CP202 CP203 CP203 TP201 TP201 TP202 Client Sample ID.: ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.20 0.80 0.25 0.50 0.20 0.60 0.10 0.70 0.20 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD Alpha-Chlordane N 2840 mg/kg 0.20 < 0.20 Endosulfan I N 2840 mg/kg 0.20 < 0.20 4,4-DDE N 2840 mg/kg 0.20 < 0.20 Dieldrin N 2840 mg/kg 0.20 < 0.20 Endrin N 2840 mg/kg 0.20 < 0.20 4,4-DDD N 2840 mg/kg 0.20 < 0.20 Endosulfan II N 2840 mg/kg 0.20 < 0.20 Endrin Aldehyde N 2840 mg/kg 0.20 < 0.20 4,4-DDT N 2840 mg/kg 0.20 < 0.20 Endosulfan Sulphate N 2840 mg/kg 0.20 < 0.20 Methoxychlor N 2840 mg/kg 0.20 < 0.20 Endrin Ketone N 2840 mg/kg 0.20 < 0.20
Page 4 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508498 508499 508500 508501 508502 508503 508504 508505 508506 Order No.: DS34488 Client Sample Ref.: TP202 TP203 TP203 TP204 TP204 TP205 TP205 TP206 TP206 Client Sample ID.: ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.50 0.30 0.60 0.10 0.60 0.20 0.50 0.10 0.40 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD ACM Type U 2192 N/A - - - - No Asbestos No Asbestos No Asbestos No Asbestos Asbestos Identification U 2192 % 0.001 Detected Detected Detected Detected Moisture N 2030 % 0.020 10 12 7.5 12 8.9 14 9.5 12 4.6 Soil Colour N 2040 N/A Brown Brown Brown Brown Orange Brown Orange Stones Brown Other Material N 2040 N/A Stones Stones Stones, Stones Stones Stones Stones Stones, Ash Stones Soil Texture N 2040 N/A Sand Sand Sand Sand Sand Sand Sand Sand Sand pH M 2010 N/A 7.8 7.6 7.5 7.5 Boron (Hot Water Soluble) M 2120 mg/kg 0.40 < 0.40 < 0.40 < 0.40 < 0.40 Sulphate (2:1 Water Soluble) as SO4 M 2120 g/l 0.010 < 0.010 < 0.010 < 0.010 < 0.010 Arsenic M 2450 mg/kg 1.0 6.5 3.5 5.3 3.7 Cadmium M 2450 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Chromium M 2450 mg/kg 1.0 13 7.8 11 11 Copper M 2450 mg/kg 0.50 5.2 3.4 7.2 2.7 Mercury M 2450 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Nickel M 2450 mg/kg 0.50 8.1 2.4 7.2 6.5 Lead M 2450 mg/kg 0.50 10 18 5.7 7.0 Selenium M 2450 mg/kg 0.20 < 0.20 < 0.20 < 0.20 < 0.20 Zinc M 2450 mg/kg 0.50 14 13 17 12 Chromium (Hexavalent) N 2490 mg/kg 0.50 < 0.50 < 0.50 < 0.50 < 0.50 Total TPH >C6-C40 M 2670 mg/kg 10 < 10 < 10 < 10 < 10 Aliphatic TPH >C5-C6 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C6-C8 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C8-C10 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C10-C12 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C12-C16 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C16-C21 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C21-C35 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aliphatic TPH >C35-C44 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Total Aliphatic Hydrocarbons N 2680 mg/kg 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 Aromatic TPH >C5-C7 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C7-C8 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C8-C10 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C10-C12 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C12-C16 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C16-C21 U 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C21-C35 M 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Aromatic TPH >C35-C44 N 2680 mg/kg 1.0 < 1.0 < 1.0 < 1.0 < 1.0 < 1.0 Page 5 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508498 508499 508500 508501 508502 508503 508504 508505 508506 Order No.: DS34488 Client Sample Ref.: TP202 TP203 TP203 TP204 TP204 TP205 TP205 TP206 TP206 Client Sample ID.: ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.50 0.30 0.60 0.10 0.60 0.20 0.50 0.10 0.40 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD Total Aromatic Hydrocarbons N 2680 mg/kg 5.0 < 5.0 < 5.0 < 5.0 < 5.0 < 5.0 Total Petroleum Hydrocarbons N 2680 mg/kg 10.0 < 10 < 10 < 10 < 10 < 10 Naphthalene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Acenaphthylene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Acenaphthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Fluorene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Phenanthrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Fluoranthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Pyrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Chrysene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[b]fluoranthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[k]fluoranthene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]pyrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Indeno(1,2,3-c,d)Pyrene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Dibenz(a,h)Anthracene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Benzo[g,h,i]perylene M 2700 mg/kg 0.10 < 0.10 < 0.10 < 0.10 < 0.10 Total Of 16 PAH's M 2700 mg/kg 2.0 < 2.0 < 2.0 < 2.0 < 2.0 Demeton-O N 2820 mg/kg 0.20 < 0.20 < 0.20 Phorate N 2820 mg/kg 0.20 < 0.20 < 0.20 Demeton-S N 2820 mg/kg 0.20 < 0.20 < 0.20 Disulfoton N 2820 mg/kg 0.20 < 0.20 < 0.20 Fenthion N 2820 mg/kg 0.20 < 0.20 < 0.20 Trichloronate N 2820 mg/kg 0.20 < 0.20 < 0.20 Prothiofos N 2820 mg/kg 0.20 < 0.20 < 0.20 Fensulphothion N 2820 mg/kg 0.20 < 0.20 < 0.20 Sulprofos N 2820 mg/kg 0.20 < 0.20 < 0.20 Azinphos-Methyl N 2820 mg/kg 0.20 < 0.20 < 0.20 Coumaphos N 2820 mg/kg 0.20 < 0.20 < 0.20 Alpha-HCH N 2840 mg/kg 0.20 < 0.20 < 0.20 Gamma-HCH (Lindane) N 2840 mg/kg 0.20 < 0.20 < 0.20 Beta-HCH N 2840 mg/kg 0.20 < 0.20 < 0.20 Delta-HCH N 2840 mg/kg 0.20 < 0.20 < 0.20 Heptachlor N 2840 mg/kg 0.20 < 0.20 < 0.20 Aldrin N 2840 mg/kg 0.20 < 0.20 < 0.20 Heptachlor Epoxide N 2840 mg/kg 0.20 < 0.20 < 0.20 Gamma-Chlordane N 2840 mg/kg 0.20 < 0.20 < 0.20 Page 6 of 9 Results - Soil
Project: 17-0337.02 - Sprowston Client: Delta Simons Chemtest Job No.: 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 17-23685 Quotation No.: Chemtest Sample ID.: 508498 508499 508500 508501 508502 508503 508504 508505 508506 Order No.: DS34488 Client Sample Ref.: TP202 TP203 TP203 TP204 TP204 TP205 TP205 TP206 TP206 Client Sample ID.: ES2 ES1 ES2 ES1 ES2 ES1 ES2 ES1 ES2 Sample Type: SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL SOIL Top Depth (m): 0.50 0.30 0.60 0.10 0.60 0.20 0.50 0.10 0.40 Date Sampled: 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 05-Sep-2017 Asbestos Lab: COVENTRY COVENTRY COVENTRY COVENTRY Determinand Accred. SOP Units LOD Alpha-Chlordane N 2840 mg/kg 0.20 < 0.20 < 0.20 Endosulfan I N 2840 mg/kg 0.20 < 0.20 < 0.20 4,4-DDE N 2840 mg/kg 0.20 < 0.20 < 0.20 Dieldrin N 2840 mg/kg 0.20 < 0.20 < 0.20 Endrin N 2840 mg/kg 0.20 < 0.20 < 0.20 4,4-DDD N 2840 mg/kg 0.20 < 0.20 < 0.20 Endosulfan II N 2840 mg/kg 0.20 < 0.20 < 0.20 Endrin Aldehyde N 2840 mg/kg 0.20 < 0.20 < 0.20 4,4-DDT N 2840 mg/kg 0.20 < 0.20 < 0.20 Endosulfan Sulphate N 2840 mg/kg 0.20 < 0.20 < 0.20 Methoxychlor N 2840 mg/kg 0.20 < 0.20 < 0.20 Endrin Ketone N 2840 mg/kg 0.20 < 0.20 < 0.20
Page 7 of 9 Test Methods
SOP Title Parameters included Method summary 2010 pH Value of Soils pH pH Meter Moisture and Stone Content of Determination of moisture content of soil as a 2030 Soils(Requirement of Moisture content percentage of its as received mass obtained at MCERTS) <37°C.
Soil Description(Requirement of As received soil is described based upon 2040 Soil description MCERTS) BS5930
Water Soluble Boron, Sulphate, 2120 Boron; Sulphate; Magnesium; Chromium Aqueous extraction / ICP-OES Magnesium & Chromium
2192 Asbestos Asbestos Polarised light microscopy / Gravimetry
Metals, including: Arsenic; Barium; Beryllium; Cadmium; Chromium; Cobalt; Copper; Lead; Acid digestion followed by determination of 2450 Acid Soluble Metals in Soils Manganese; Mercury; Molybdenum; Nickel; metals in extract by ICP-MS. Selenium; Vanadium; Zinc
Soil extracts are prepared by extracting dried and ground soil samples into boiling water. 2490 Hexavalent Chromium in Soils Chromium [VI] Chromium [VI] is determined by ‘Aquakem 600’ Discrete Analyser using 1,5-diphenylcarbazide.
Total Petroleum Hydrocarbons TPH (C6–C40); optional carbon banding, e.g. 3- 2670 Dichloromethane extraction / GC-FID (TPH) in Soils by GC-FID band – GRO, DRO & LRO*TPH C8–C40
Aliphatics: >C5–C6, >C6–C8,>C8–C10, >C10–C12, >C12–C16, >C16–C21, >C21– Dichloromethane extraction / GCxGC FID 2680 TPH A/A Split C35, >C35– C44Aromatics: >C5–C7, >C7–C8, detection >C8– C10, >C10–C12, >C12–C16, >C16– C21, >C21– C35, >C35– C44
Acenaphthene; Acenaphthylene; Anthracene; Benzo[a]Anthracene; Benzo[a]Pyrene; Speciated Polynuclear Benzo[b]Fluoranthene; Benzo[ghi]Perylene; 2700 Aromatic Hydrocarbons (PAH) Benzo[k]Fluoranthene; Chrysene; Dichloromethane extraction / GC-FID in Soil by GC-FID Dibenz[ah]Anthracene; Fluoranthene; Fluorene; Indeno[123cd]Pyrene; Naphthalene; Phenanthrene; Pyrene
Organophosphorus pesticide representative Organophosphorus (O-P) 2820 suite including Parathion, Malathion etc, plus Dichloromethane extraction / GC-MS Pesticides in Soils by GC-MS client specific determinands
Organochlorine pesticide representative suite Organochlorine (O-Cl) 2840 including DDT and its metabolites, ‘drins’ and Dichloromethane extraction / GC-MS Pesticides in Soils by GC-MS HCH etc, plus client specific determinands
Page 8 of 9 Report Information
Key U UKAS accredited M MCERTS and UKAS accredited N Unaccredited S This analysis has been subcontracted to a UKAS accredited laboratory that is accredited for this analysis SN This analysis has been subcontracted to a UKAS accredited laboratory that is not accredited for this analysis T This analysis has been subcontracted to an unaccredited laboratory I/S Insufficient Sample U/S Unsuitable Sample N/E not evaluated < "less than" > "greater than"
Comments or interpretations are beyond the scope of UKAS accreditation The results relate only to the items tested Uncertainty of measurement for the determinands tested are available upon request None of the results in this report have been recovery corrected All results are expressed on a dry weight basis The following tests were analysed on samples as received and the results subsequently corrected to a dry weight basis TPH, BTEX, VOCs, SVOCs, PCBs, Phenols For all other tests the samples were dried at < 37°C prior to analysis All Asbestos testing is performed at the indicated laboratory Issue numbers are sequential starting with 1 all subsequent reports are incremented by 1
Sample Deviation Codes A - Date of sampling not supplied B - Sample age exceeds stability time (sampling to extraction) C - Sample not received in appropriate containers D - Broken Container E - Insufficient Sample
Sample Retention and Disposal All soil samples will be retained for a period of 45 days from the date of receipt All water samples will be retained for 14 days from the date of receipt Charges may apply to extended sample storage
If you require extended retention of samples, please email your requirements to: [email protected]
Page 9 of 9
Appendix G – Groundwater Chemical Analysis Results
Environment | Health & Safety | Sustainability Chemtest Ltd. Depot Road Newmarket CB8 0AL Tel: 01638 606070 Email: [email protected] Final Report
Report No.: 17-24316-1
Initial Date of Issue: 19-Sep-2017
Client Delta Simons
Client Address: 3 Henley Office Park Doddington Road Lincoln Lincolnshire LN6 3QR
Contact(s): Gemma Tatton Tom Horner
Project 17-0337.02 Sprowston
Quotation No.: Date Received: 15-Sep-2017
Order No.: DS34576 Date Instructed: 15-Sep-2017
No. of Samples: 3
Turnaround (Wkdays): 3 Results Due: 19-Sep-2017
Date Approved: 19-Sep-2017
Approved By:
Details: Keith Jones, Technical Manager
Page 1 of 5 Results - Water
Project: 17-0337.02 Sprowston Client: Delta Simons Chemtest Job No.: 17-24316 17-24316 17-24316 Quotation No.: Chemtest Sample ID.: 511584 511585 511586 Order No.: DS34576 Client Sample Ref.: CP201 CP202 CP203 Sample Type: WATER WATER WATER Date Sampled: 13-Sep-2017 13-Sep-2017 13-Sep-2017 Determinand Accred. SOP Units LOD pH U 1010 N/A 6.9 7.1 6.9 Sulphate U 1220 µg/l 1000 27000 140000 560000 Arsenic (Dissolved) U 1450 µg/l 1.0 < 1.0 < 1.0 < 1.0 Boron (Dissolved) U 1450 µg/l 20 240 57 100 Cadmium (Dissolved) U 1450 µg/l 0.080 0.084 < 0.080 0.69 Chromium (Dissolved) U 1450 µg/l 1.0 21 8.6 17 Copper (Dissolved) U 1450 µg/l 1.0 2.4 < 1.0 1.4 Mercury (Dissolved) U 1450 µg/l 0.50 2.7 1.6 2.3 Nickel (Dissolved) U 1450 µg/l 1.0 < 1.0 < 1.0 30 Lead (Dissolved) U 1450 µg/l 1.0 1.1 < 1.0 < 1.0 Selenium (Dissolved) U 1450 µg/l 1.0 2.1 2.1 2.1 Zinc (Dissolved) U 1450 µg/l 1.0 18 18 28 Aliphatic TPH >C5-C6 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C6-C8 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C8-C10 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C10-C12 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C12-C16 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C16-C21 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C21-C35 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aliphatic TPH >C35-C44 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Total Aliphatic Hydrocarbons N 1675 µg/l 5.0 < 5.0 < 5.0 < 5.0 Aromatic TPH >C5-C7 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C7-C8 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C8-C10 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C10-C12 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C12-C16 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C16-C21 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C21-C35 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Aromatic TPH >C35-C44 N 1675 µg/l 0.10 < 0.10 < 0.10 < 0.10 Total Aromatic Hydrocarbons N 1675 µg/l 5.0 < 5.0 < 5.0 < 5.0 Total Petroleum Hydrocarbons N 1675 µg/l 10 < 10 < 10 < 10 Naphthalene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Acenaphthylene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Acenaphthene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Fluorene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Phenanthrene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Anthracene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Fluoranthene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Pyrene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]anthracene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Chrysene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Page 2 of 5 Results - Water
Project: 17-0337.02 Sprowston Client: Delta Simons Chemtest Job No.: 17-24316 17-24316 17-24316 Quotation No.: Chemtest Sample ID.: 511584 511585 511586 Order No.: DS34576 Client Sample Ref.: CP201 CP202 CP203 Sample Type: WATER WATER WATER Date Sampled: 13-Sep-2017 13-Sep-2017 13-Sep-2017 Determinand Accred. SOP Units LOD Benzo[b]fluoranthene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Benzo[k]fluoranthene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Benzo[a]pyrene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Indeno(1,2,3-c,d)Pyrene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Dibenz(a,h)Anthracene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Benzo[g,h,i]perylene U 1700 µg/l 0.10 < 0.10 < 0.10 < 0.10 Total Of 16 PAH's U 1700 µg/l 2.0 < 2.0 < 2.0 < 2.0 Benzene U 1760 µg/l 1.0 < 1.0 < 1.0 < 1.0 Toluene U 1760 µg/l 1.0 < 1.0 < 1.0 < 1.0 Ethylbenzene U 1760 µg/l 1.0 < 1.0 < 1.0 < 1.0 m & p-Xylene U 1760 µg/l 1.0 < 1.0 < 1.0 < 1.0 o-Xylene U 1760 µg/l 1.0 < 1.0 < 1.0 < 1.0
Page 3 of 5 Test Methods
SOP Title Parameters included Method summary 1010 pH Value of Waters pH pH Meter Fluoride; Chloride; Nitrite; Nitrate; Total; Anions, Alkalinity & Ammonium Automated colorimetric analysis using 1220 Oxidisable Nitrogen (TON); Sulfate; Phosphate; in Waters ‘Aquakem 600’ Discrete Analyser. Alkalinity; Ammonium Metals, including: Antimony; Arsenic; Barium; Beryllium; Boron; Cadmium; Chromium; Cobalt; Filtration of samples followed by direct 1450 Metals in Waters by ICP-MS Copper; Lead; Manganese; Mercury; determination by inductively coupled plasma Molybdenum; Nickel; Selenium; Tin; Vanadium; mass spectrometry (ICP-MS). Zinc
Aliphatics: >C5–C6, >C6–C8, >C8– C10, TPH Aliphatic/Aromatic split in >C10–C12, >C12–C16, >C16–C21, >C21– 1675 Waters by GC-FID(cf. Texas C35, >C35– C44Aromatics: >C5–C7, >C7–C8, Pentane extraction / GCxGC FID detection Method 1006 / TPH CWG) >C8– C10, >C10–C12, >C12–C16, >C16– C21, >C21– C35, >C35– C44
Acenaphthene; Acenaphthylene; Anthracene; Benzo[a]Anthracene; Benzo[a]Pyrene; Speciated Polynuclear Benzo[b]Fluoranthene; Benzo[ghi]Perylene; 1700 Aromatic Hydrocarbons (PAH) Benzo[k]Fluoranthene; Chrysene; Pentane extraction / GC FID detection in Waters by GC-FID Dibenz[ah]Anthracene; Fluoranthene; Fluorene; Indeno[123cd]Pyrene; Naphthalene; Phenanthrene; Pyrene
Automated headspace gas chromatographic Volatile Organic Compounds Volatile organic compounds, including BTEX (GC) analysis of water samples with mass 1760 (VOCs) in Waters by and halogenated Aliphatic/Aromatics. (cf. spectrometric (MS) detection of volatile organic Headspace GC-MS USEPA Method 8260) compounds.
Page 4 of 5 Report Information
Key U UKAS accredited M MCERTS and UKAS accredited N Unaccredited S This analysis has been subcontracted to a UKAS accredited laboratory that is accredited for this analysis SN This analysis has been subcontracted to a UKAS accredited laboratory that is not accredited for this analysis T This analysis has been subcontracted to an unaccredited laboratory I/S Insufficient Sample U/S Unsuitable Sample N/E not evaluated < "less than" > "greater than"
Comments or interpretations are beyond the scope of UKAS accreditation The results relate only to the items tested Uncertainty of measurement for the determinands tested are available upon request None of the results in this report have been recovery corrected All results are expressed on a dry weight basis The following tests were analysed on samples as received and the results subsequently corrected to a dry weight basis TPH, BTEX, VOCs, SVOCs, PCBs, Phenols For all other tests the samples were dried at < 37°C prior to analysis All Asbestos testing is performed at the indicated laboratory Issue numbers are sequential starting with 1 all subsequent reports are incremented by 1
Sample Deviation Codes A - Date of sampling not supplied B - Sample age exceeds stability time (sampling to extraction) C - Sample not received in appropriate containers D - Broken Container E - Insufficient Sample
Sample Retention and Disposal All soil samples will be retained for a period of 45 days from the date of receipt All water samples will be retained for 14 days from the date of receipt Charges may apply to extended sample storage
If you require extended retention of samples, please email your requirements to: [email protected]
Page 5 of 5
Appendix H – Field Monitoring Data/Gas Monitoring Data
Environment | Health & Safety | Sustainability WEATHER Start End Site Name GT20 (Parcels R1-R4), Sprowston Job number 17-0337.02 Time N/A N/A Pressure (mb) 992 994 Client Taylor Wimpey, Persimmon Homes and Hopkins Homes Recorded by Gemma Tatton Wind speed (m/s) NR NR Date (DD/MM/YYYY) 13/09/2017 Wind Dir. (from) NR NR Gas Analyser GFM435 (Gas Kit 5) - 12233 Visit Number 1 Temperature (°C) 14.00 14.00
Readings at start CH4 (% v/v) NR CO2 (% v/v) NR O2 (% v/v) NR H2S (ppm) NR Dry/Rain/Snow/Ice Dry Dry Rising/Falling Trend (for the General comments Falling three days before visit) GROUND GAS GROUNDWATER
Flow CH4 CO2 O2 H2S CO VOC Notes
Ref Diff.
Atmos. Atmos. Pressure
l/hr % v/v % v/v % v/v ppm Pressure product product
product product (e.g. water colour, sheen, odour, damage to well or gas tap, flooded ground etc.)
Depth to free free free to to Depth Depth
Depth to base base to to Depth Depth Depth to water to Depth mb mb water to Depth Max Max Max Min Max Max Max Steady Steady Steady Steady m m m The formulae require that only numbers, "<0.1" for ground gas and flow or "DRY" for groundwater are entered in the sheet CP201 <0.1 <0.1 <0.1 <0.1 4.1 4.0 15.8 15.9 992 7.92 9.56 Orangish brown water. CP202 0.3 <0.1 <0.1 <0.1 3.1 1.3 18.8 19.0 994 5.03 9.20 Orangish brown water. CP203 2.8 0.7 <0.1 <0.1 4.4 4.3 15.4 15.4 994 7.27 10.06 Orangish brown water.
Document No. C101 Version: 1.0 Issue Date: 11/07/17 Author: J Rhoades / S Steele Authorised By:K Hughes © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted. WEATHER Start End Site Name GT20 (Parcels R1-R4), Sprowston Job number 17-0337.02 Time N/A N/A Pressure (mb) 1016 1015 Client Taylor Wimpey, Persimmon Homes and Hopkins Homes Recorded by Gemma Tatton Wind speed (m/s) NR NR Date (DD/MM/YYYY) 19/09/2017 Wind Dir. (from) NR NR Gas Analyser GFM435 (Gas Kit 5) - 12233 Visit Number 2 Temperature (°C) 15.00 15.00
Readings at start CH4 (% v/v) NR CO2 (% v/v) NR O2 (% v/v) NR H2S (ppm) NR Dry/Rain/Snow/Ice Dry Dry Rising/Falling Trend (for the General comments Rising three days before visit) GROUND GAS GROUNDWATER
Flow CH4 CO2 O2 H2S CO VOC Notes
Ref Diff.
Atmos. Atmos. Pressure
l/hr % v/v % v/v % v/v ppm Pressure product product
product product (e.g. water colour, sheen, odour, damage to well or gas tap, flooded ground etc.)
Depth to free free free to to Depth Depth
Depth to base base to to Depth Depth Depth to water to Depth mb mb water to Depth Max Max Max Min Max Max Max Steady Steady Steady Steady m m m The formulae require that only numbers, "<0.1" for ground gas and flow or "DRY" for groundwater are entered in the sheet CP201 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 19.7 20.6 1016 7.97 9.62 CP202 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 20.5 20.8 1018 5.04 8.78 CP203 <0.1 <0.1 <0.1 <0.1 2.5 2.5 14.4 14.5 1015 7.33 9.78
Document No. C101 Version: 1.0 Issue Date: 11/07/17 Author: J Rhoades / S Steele Authorised By:K Hughes © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted. WEATHER Start End Site Name GT20 (Parcels R1-R4), Sprowston Job number 17-0337.02 Time N/A N/A Pressure (mb) 1013 1012 Client Taylor Wimpey, Persimmon Homes and Hopkins Homes Recorded by Gemma Tatton & Aidan Nelson Wind speed (m/s) NR NR Date (DD/MM/YYYY) 28/09/2017 Wind Dir. (from) NR NR Gas Analyser GFM435 (Gas Kit 5) - 12233 Visit Number 3 Temperature (°C) 15.00 15.00
Readings at start CH4 (% v/v) NR CO2 (% v/v) NR O2 (% v/v) NR H2S (ppm) NR Dry/Rain/Snow/Ice Rain Dry Rising/Falling Trend (for the General comments Rising three days before visit) GROUND GAS GROUNDWATER
Flow CH4 CO2 O2 H2S CO VOC Notes
Ref Diff.
Atmos. Atmos. Pressure
l/hr % v/v % v/v % v/v ppm Pressure product product
product product (e.g. water colour, sheen, odour, damage to well or gas tap, flooded ground etc.)
Depth to free free free to to Depth Depth
Depth to base base to to Depth Depth Depth to water to Depth mb mb water to Depth Max Max Max Min Max Max Max Steady Steady Steady Steady m m m The formulae require that only numbers, "<0.1" for ground gas and flow or "DRY" for groundwater are entered in the sheet CP201 <0.1 <0.1 <0.1 <0.1 3.8 3.8 15.8 15.8 1013 7.97 9.44 CP202 <0.1 <0.1 <0.1 <0.1 4.0 4.0 17.1 17.1 1014 5.02 8.62 CP203 0.4 0.2 <0.1 <0.1 3.7 3.7 15.1 15.1 1012 7.35 9.65
Document No. C101 Version: 1.0 Issue Date: 11/07/17 Author: J Rhoades / S Steele Authorised By:K Hughes © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted. WEATHER Start End Site Name GT20 (Parcels R1-R4), Sprowston Job number 17-0337.02 Time 10:30 12:00 Pressure (mb) 1014 1014 Client Taylor Wimpey, Persimmon Homes and Hopkins Homes Recorded by DK Wind speed (m/s) NR NR Date (DD/MM/YYYY) 04/10/2017 Wind Dir. (from) NR NR Gas Analyser GFM435 (Gas Kit 5) - 12233 Visit Number 4 Temperature (°C) 15.00 16.00
Readings at start CH4 (% v/v) 0.0 CO2 (% v/v) 0.1 O2 (% v/v) 20.6 H2S (ppm) -50 Dry/Rain/Snow/Ice DRY DRY Rising/Falling Trend (for the General comments N/A three days before visit) GROUND GAS GROUNDWATER
Flow CH4 CO2 O2 H2S CO VOC Notes
Ref Diff.
Atmos. Atmos. Pressure
l/hr % v/v % v/v % v/v ppm Pressure product product
product product (e.g. water colour, sheen, odour, damage to well or gas tap, flooded ground etc.)
Depth to free free free to to Depth Depth
Depth to base base to to Depth Depth Depth to water to Depth mb mb water to Depth Max Max Max Min Max Max Max Steady Steady Steady Steady m m m The formulae require that only numbers, "<0.1" for ground gas and flow or "DRY" for groundwater are entered in the sheet CP201 0.4 0.4 0.0 0.0 3.3 3.3 16.7 16.7 0 0 1014 7.95 9.47 CP202 0.0 0.0 0.0 0.0 0.1 0.1 20.8 20.8 0 0 1014 5.02 8.60 CP203 0.3 0.3 0.0 0.0 3.2 3.2 15.2 15.2 0 0 1014 7.35 8.68
Document No. C101 Version: 1.0 Issue Date: 11/07/17 Author: J Rhoades / S Steele Authorised By:K Hughes © Delta-Simons Environmental Consultants Limited. No part of this document may be reproduced unless prior written permission has been granted.