The Britannia Project Phase 1B

0042977-BHE-XX-XX-RP-YG-0006

Copyright © 1976 - 2020 BuroHappold Engineering. All Rights Reserved.

The Britannia Project – Phase 1B

Verification Report (Part A - Groundworks)

0042977

13 March 2020

Revision P02

The Britannia Project – Phase 1B Revision P02

Verification Report (Part A - Groundworks) 13 March 2020

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0042977-BHE-XX-XX-RP-YG-0006

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Report\0042977-BHE-XX-XX-RP-YG-0006 P02.docx

This report has been prepared for the sole benefit, use and information of Morgan Sindall for the purposes set out in

the report or instructions commissioning it. The liability of Buro Happold Limited in respect of the information

contained in the report will not extend to any third party.

author Georgina Sopp

date 13/03/2020

approved Hugh Mallett

signature

date 13/03/2020



Copyright © 1976 - 2020 BuroHappold Engineering. All Rights Reserved. Page 5

0042977-BHE-XX-XX-RP-YG-0006

Contents

1 Introduction 6

2 Background information 8

3 Conceptual Site Model (CSM) 9

4 Planned Remediation Actions 11

5 Verification Plan 13

6 Verification of Groundworks 15

7 Conclusions 21

References 22

Appendix A Method statements

Appendix B Site inspection notes

Appendix C Kelbray Remediation works

Appendix D FDL substructure works

Appendix E Below ground infrastructure




1 Introduction

1.1 Report scope and objectives

This Verification Report (Part A) was prepared by BuroHappold Engineering on behalf of Morgan Sindall. It provides

the evidence of the successful completion of the initial elements (Part A - Groundworks) of the approved Remediation

Scheme [1, 2] relevant to the Phase 1B development of The Britannia Project, Britannia School, see Figure 1-1.

As described in the Verification Plan [3], the verification activities for each phase are being reported in two parts. This

part (Part A – Groundworks) has been prepared on completion of the main programme of below ground works

associated with the School development. The second part (Part B – Landscaping) will be prepared on completion of

the landscaping within this development phase. Verification of remediation within Phases 1A, 2A and 2B will be

reported separately.

The particular objectives of this report are to: (i) describe the verification activities that have been carried out; (ii)

present the supporting information on the remedial measures undertaken to mitigate the risks identified by site

investigation; and (iii) describe the presence and remediation of any unforeseen contamination encountered during

the construction works.

This Verification Report has been prepared in general accordance with the Environment Agency Model Procedures [4]

and its replacement currently in draft [5] and has also taken into account the programme of investigation carried out

for the redevelopment [6, 7, 8], the nature of the development activities (School) and the approved Remediation

Scheme [1, 2].

Figure 1-1 – Illustrative phased masterplan for The Britannia Project; Phase 1A is relevant to this report.




1.2 Remediation scheme

There are two documents relevant to the Remediation Scheme for the Britannia School (Phase 1B) development:

1. Site-wide Remediation Scheme (0036399-BHE-XX-XX-RP-YG-0005) [1] – presents the overarching

remediation principles relevant to the entire development; and

2. Phase 1B Remediation Addendum (0042977-BHE-XX-XX-DN-YG-0001) [2] – describes the particular

remediation design or actions specific to Phase 1B that are not included or are a modification, alteration or

omission from that site-wide strategy.

1.3 Relevant planning conditions

This report has been prepared to address the requirements of the Local Planning Authority with respect to land

affected by contamination, set out in the particular conditions of the planning permission. The relevant planning

condition is presented below for ease of reference:

Condition 20 – The remediation scheme for each phase shall be implemented in accordance with the approved

timetable of works. Within 3 months of the completion of measures identified in the approved remediation scheme, a

validation report for each phase (that demonstrates the effectiveness of the remediation carried out) must be submitted

to the Local Planning Authority.

In order to enable discharge of Condition 20, a verification (validation) report is required that demonstrates how the

risks from contamination have been mitigated by the implementation of the Remediation Scheme [1, 2]. As described

above, this report forms the first part of a two-part verification process. A second verification report (Part B –

Landscaping) will be submitted on completion of all imported soils within soft landscaped areas (anticipated to be in

the early months of 2021).

1.4 Responsible parties

The parties with responsibility for various elements of the verification activities are summarised in Table 1-1.

Table 1-1 - Responsible parties.

Name Role Description of activities Contact information

Hackney Council Developer Overall responsibility for activities related to

the development.

Hackney Town Hall, Mare Street,

London, E8 1EA

Morgan Sindall Principal

Contractor

Overall responsibility for Phase 1B

construction

10th Floor, One Eversholt Street,

London, NW1 2DN

BuroHappold

Engineering

Consultant to

Morgan Sindall

Preparation of the Remediation Strategy,

and management of verification and

preparation of Verification Report

17 Newman Street, London, W1T

1PD

Keltbray Remediation Sub-contractor Responsible for enabling earthworks,

including excavation / treatment of Made

Ground.

Keltbray Group, St Andrew’s House,

Portsmouth Rd, Esher, KT10 9TA

Keltbray Piling Sub-contractor Construction of permanent sheet piled wall. Keltbray Group, St Andrew’s House,

Portsmouth Rd, Esher, KT10 9TA

Foundation

Developments Limited

Sub-contractor Bulk excavation, piling mat installation and

construction of sub-structure

Foundation House, Clarendon

Road, Surrey, SM6 8QX




2 Background information

2.1 Site setting

The Britannia Project masterplan site is located within the London Borough of Hackney. The masterplan area is

bounded to the north by Penn Street and Hyde Road, to the east by Pitfield Street, to the south by Shoreditch Park

and to the west by Bridport Place, with Shoreditch Park beyond. The Phase 1B area sits within the former carpark and

public realm areas external to the original Britannia Leisure Centre.

2.2 Phase 1B development – Britannia School

Britannia School is bounded by Penn Street (north), Pitfield Street (east), Grange Street (south) and Northport Street /

residential properties (west). The building is of 4/5 storeys, with a basement of about 1,100m2 in the northeast part,

and founded on a raft foundation laying on natural strata of the River Terrace Deposits. The basement excavation is

supported by permanent sheet piles.

2.3 Masterplan area history

Previous developments within the masterplan area include a paper manufacturing works, engineering works, a

vicarage and residential properties. Most recently (i.e. prior to this current redevelopment), the masterplan area was

occupied by Britannia Leisure Centre and associated car park, a school playground and part located within Shoreditch

Park.

2.4 Site investigations

A ground investigation across the masterplan area was designed by BuroHappold Engineering and undertaken by

SocoTec in October to December 2017 [7]. A second ground investigation was designed by Morgan Sindall and

undertaken by SocoTec in November 2018 [6]. An archaeological investigation was also undertaken in late 2018, but

no formal report was prepared. The results of these investigations are summarised here in Chapter 3.




3 Conceptual Site Model (CSM)

3.1 Geology, hydrogeology and hydrology

Ground investigation confirmed ground conditions within the masterplan area to be broadly as expected, comprising a

variable thickness of Made Ground (up to 6m) and Alluvium overlying River Terrace Gravels and London Clay. Lambeth

Beds, Thanet Sands and Chalk underly the site.

There are two aquifer bodies of relevance; a Secondary A Aquifer in River Terrace Deposits and Principal Aquifer in

Thanet Sands and Upper Chalk at about 40-50m bgl. Based on the results of groundwater monitoring, a hydrostatic

characteristic groundwater level of +15mOD was adopted for near-surface strata and -20mOD adopted for the lower

aquifer in Thanet Sands and Upper Chalk.

3.2 Profile of residual contamination

3.2.1 Soil

Some heavy metals (particularly lead), PAHs and asbestos fragments have all been identified as the contaminants of

concern where concentrations were found to be elevated above residential screening standards across the site. Less

than 10% of soil samples in the BuroHappold investigation recorded the presence of trace concentrations of asbestos.

No suspect fragments were encountered during the intrusive ground investigations but laboratory analysis identified

asbestos fragments >10mm during the quantification analysis. A proportion of the materials encountered within the

trenches from the archaeological investigation contained asbestos. Based on the evidence from the intrusive ground

investigations and the recent findings from the archaeological investigation, asbestos containing material is likely to

be present as fragments / artefacts within the Made Ground. If present as free fibres disseminated within the soil, it is

most likely that the majority of concentrations will be of trace amounts or as small fragments below the hazardous

waste threshold (0.1%).

3.2.2 Controlled Waters

A total of three samples of shallow groundwater were tested. The majority of inorganic and organic determinands

within the majority of the samples tested did not exceed the relevant thresholds for groundwater. Concentrations of

zinc elevated above the Freshwater EQS threshold were recorded in all three samples. One sample also contained a

concentration of chromium elevated above the Freshwater EQS threshold. No elevated concentrations of speciated

PAHs were recorded with almost all samples recording concentrations below the limit of detection.

3.2.3 Ground gas and vapour

The assessed level of risk related to ground gas was low (associated with slightly elevated concentrations of CO2). This

is further mitigated by the planned construction, namely the removal of the source by basement excavation and by the

presence / structure of the basement slab.




3.3 Summary of potential pollutant linkages

In the UK, the assessment of risk from contamination follows the source-pathway-receptor approach. Site-specific

pathway-receptor linkages have been identified with respect to the sources summarised above and with respect to the

proposed use as a school (for Phase 1B). A summary of the potential pollutant linkages relevant to this proposed

development are tabulated below for ease of reference.

Table 3-1 - Summary of pollutant linkages.

Receptor Pathway Source

Human

Health

Offsite residents

/ visitors

Soil and dust inhalation / ingestion

during construction/earthworks.

Made Ground with elevated concentrations of some

heavy metals (in particular lead), some PAHs,

petroleum hydrocarbons and asbestos.

Construction

workers

Direct contact and dermal uptake,

soil and dust ingestion during

construction/earthworks.

Controlled

Waters

River Terrace

Gravels

[Secondary

aquifer]

Migration via permeable strata and

surface water drainage

Made Ground with elevated concentrations of some

heavy metals (in particular lead), some PAHs and

petroleum hydrocarbons.

Environment Flora Direct contact / uptake by plant roots Made Ground with elevated copper and zinc with

phytotoxic effects on plants in soft landscape areas.

Buildings/

Services

Proposed

buildings and

structures.

Direct contact / permeation of plastic

pipe work by contaminants in soil

and leachate. Degradation of below

ground concrete.

The Aggressive Chemical Environment for Concrete

(ACEC) classification for brownfield locations (Made

Ground) is DS-2 and AC-2. The ACEC classification

for natural ground is DS-3 and AC-2s.

Where Made Ground remains in situ barrier pipe

materials are required due to elevated

concentrations of heavy end TPHs and PAHs.




4 Planned Remediation Actions

4.1 Remediation Aims and Objectives

The remediation actions are set out in the Site-wide Remediation Scheme [1] and Phase 1B Addendum [2] is

summarised in the text below (Note: Not all of these objectives are relevant to the groundworks on Phase 1B but are

included here for completeness). In a departure from the site-wide scheme, the Phase 1B Addendum [2] did identify

additional remedial design / actions (see Section 4.2). The overall aim of the strategy is to ensure that potential risks

from land contamination at the site to future site users, neighbours, controlled waters, property and ecological

systems are appropriately mitigated. The strategy also aims to ensure that the development itself can be carried out

safely without unacceptable risks to workers, neighbours and other offsite receptors, in accordance with the National

Planning Policy Framework [9].

The specific aims of the strategy can be defined in three categories (i) contamination related; (ii) engineering relations;

and (iii) management / amenity related. These objectives are set out in turn below.

4.1.1 Contamination Related Objectives

1. To ensure workers engaged in the redevelopment are not exposed to concentrations of contamination in

the solid, liquid or gaseous/vapour phase at concentrations that could give rise to acute risks;

2. To ensure site neighbours are not exposed to concentrations of contamination in dusts at concentration

that could give rise to acute risks;

3. To ensure future site occupiers and/or visitors are not exposed to concentrations of contamination in the

solid or gaseous/vapour phase that could give rise to acute or chronic risks;

4. To ensure the quality of groundwater resources (Secondary Aquifer) are not significantly impacted by any

potentially mobile inorganic or organic contaminants in both the short and long terms;

5. To ensure soils in areas of soft landscaping meet appropriate physical and chemical criteria to enable

health / growth of on-site plants; and

6. To ensure that the redeveloped site cannot be determined as ‘Contaminated Land’.

4.1.2 Engineering Related Objectives

1. To ensure integration of the engineering design with the remediation (in particular related to the

basement construction);

2. To ensure that building materials are not subject to chemical degradation;

3. To ensure that the foundation design does not give rise to preferential pathways for migration of

contamination that could significantly impact upon the quality of the Principal aquifer.

4.1.3 Management and Amenity Related Objectives

1. To deliver the redeveloped site to time and budget;

2. To enable discharge of the relevant planning condition(s);

3. To minimise environmental impacts and ensure that ‘nuisance’ effects to neighbours are mitigated to

acceptably low levels; and

4. To ensure the remedial works undertaken are cost effective.




4.2 Additional remedial / design actions for Phase 1B

The Secondary School will be founded on a raft foundation. This approach reflects the requirements of the

substructure above and the proposed rail tunnels (Crossrail) below. A basement of approximately 1,100m2 is proposed

beneath the northeast part of the school. Accordingly, large volumes of near surface soils (mostly Made Ground) will

require removal in order to reach competent bearing strata, the underlying River Terrace Deposits. In departure from

the Site-Wide Remediation Scheme, a proportion of the Made Ground arising from this excavation (2,911m3) was

planned to be treated (by lime / cement) if required, placed and compacted as specified [10] in layers to bring the

ground elevation beneath the structural slab up to formation level. This activity was planned to be carried out in

accordance with the approved Materials Management Plan [11]. The verification of these activities is described in

Section 6.3.3.

4.3 Critical performance characteristics

4.3.1 Principles and preferred option

For the main contaminants of concern (e.g. heavy metals, PAHs and asbestos), there are no known methods of

treatment that would have the potential to remove or reduce or remove this contaminant concentration by

degradation. However, risks from contamination can only exist if there is a source of contamination present, a receptor

to be impacted upon and a plausible pathway by which the two may be linked. Breaking the pollutant linkages can be

achieved by one or more of the following methods:

i. Source control (e.g. removal); and/or

ii. Pathway control or receptor control.

Contamination in the Made Ground has been found on a widespread basis. Accordingly, the preferred remediation

option was control by;

i. Prevention or at least minimising the potential for site users to come into direct contact with contaminants

in the Made Ground soils in areas of soft landscaping.

4.3.2 Control measures for direct contact

The proposed landscaping for Phase 1B has not been confirmed, however it is anticipated there will be soft

landscaped areas in the building surrounds.

Where areas of soft landscaping are to be lain on top of existing site materials, a marker layer will be required. This is a

highly visible layer (i.e. colourful geotextile) which shall act as a visual barrier separating the existing materials from the

clean imported material.

All topsoil to be used as part of the landscaped areas of the development must comply with the physical, biological

and chemical parameters set out in the Scheme [1]. Made Ground unsuitable as a sub soil (i.e. not complying with the

physical and chemical parameters set out in this specification) will not be re-used on site in landscaped areas.

For imported soils within the planters, the horticultural specification will define the thickness requirement, for areas

where landscaping is underlain by natural soils a minimum thickness of 600mm of clean materials suitable for the

protection of human health will be required. This is in addition to any suitability requirements set out by the landscape

architect.




5 Verification Plan

5.1 General

BuroHappold Engineering prepare a Verification Plan for the Phase 1B – Secondary School, relevant to the local

planning authority Conditions 13 and 20 [3]. The planned verification work included: periodic site inspection; recording

of relevant works and provision for urgent response in the event of encountering unexpected contamination. A

summary of the Plan is presented below.

5.2 Construction workforce - Health safety and hygiene regime

The planned activities under this heading comprised;

• Review of the Contractor’s HSE/CCoC Plan and its implementation

• Periodic inspection by BuroHappold Engineering.

• Provision for immediate attendance by BuroHappold Engineering if unforeseen hazards were encountered.

5.3 Earthworks

5.3.1 Excavated soils

Made Ground

Substantial volumes of Made Ground arisings were planned to be derived from the basement excavation as described

above (section 4.2). In a departure from the site-wide strategy, a proportion of the Made Ground spoil arising from this

excavation (2,911m3) planned to be treated (by the addition of lime / cement) if required, placed and compacted as

specified [10] in layers in the excavated area to bring the ground elevation up to formation level (in accordance with

the approved Materials Management Plan [11]). Surplus spoil (approximately 6,970m3) planned to be sent off site for

treatment / disposal.

Consistent with the site-wide strategy, during the excavation and handling of spoil material a watching brief planned

to be maintained and any unsuitable materials segregated, stockpiled and subject to laboratory testing to enable

appropriate treatment / disposal off-site.

Natural Strata

The basement (and other deep) excavations (e.g. piling) was anticipated to result in spoil arisings of natural material

(sands and gravels from the RTDs and clays from the London Clay formation) which would be classified as Inert and

chemically suitable for reuse either on or off site.

Records of off-site spoil disposal were planned to be obtained and reported. Those records will include: volume;

description; classification; destination etc. Copies of the waste tickets will be retained by the Contractor in accordance

with the Duty of Care Regulations (selected records to be presented in the Verification Report). Copies of any

additional chemical testing (e.g. carried out/ required by the receiving landfill) were planned to be retained by the

Contractor to be presented in the Verification Report.




5.3.2 Imported soil materials

The physical and chemical suitability of imported materials for temporary use (e.g. pile mat, or similar) was planned to

be determined by the provision of data from the supplier. If that data is inadequate (with respect to frequency or

suspect quality) it was planned to be supplemented by analysis at a frequency of approximately 1 sample per 500m³

and at least three samples per source (whichever is greater). Each source of imported material was to be approved

before the material is transported to site. It was required to comply with the requirements set out in Table 4-1 within

the Site-wide Remediation Scheme [1]. Non-compliance

5.3.3 Non-compliance

The Plan required the Contractor to either carry out further testing to demonstrate compliance or to excavate and

remove the non-compliant soils and replace them with fresh imported materials with further sampling of the fresh

imported material to confirm suitability.

5.4 Unexpected contamination

The site investigations indicate variably impacted materials with a potential to encounter relatively localised more

grossly contaminated materials. The potential risks related to any such localised / gross or otherwise unforeseen

contamination was planned to be mitigated by the following management regime:

i. A ‘watching brief’ by the Engineer to involve periodic inspection,

ii. The Contractor’s toolbox talk to alert the construction workforce to the potential for unforeseen

contamination etc.

iii. In the event of any unforeseen contamination being encountered an appropriately qualified

environmental specialist from the Engineer was to visit the site as soon as practicable (but within a

maximum of 24 hours) to determine the need for and scope of any remedial action,

iv. Any such action was to be appropriately recorded and included in the Verification Report.

5.5 Environmental monitoring

In the event that significant amounts of suspected asbestos containing material were identified, air monitoring was

planned to be carried out in accordance with HSE guidance and the Contractors Method Statement.

5.6 Independent inspection

The Plan identified BuroHappold Engineering as responsible for the provision of a watching brief comprising;

i. Periodic site inspection,

ii. Ad hoc responses to requests for advice (e.g. if unexpected contamination is encountered)

iii. Liaison with the local authority if unforeseen contamination is encountered.




6 Verification of Groundworks

6.1 Introduction

The following text describes the data obtained providing the necessary lines of evidence set out in the Verification

Plan. Much of this information is presented in a series of Appendices to this report which are cross referenced in the

appropriate section of the text.

6.2 Construction workforce – health, safety and hygiene regime

During the groundwork activities, standard health, safety and hygiene practises were adopted in accordance with the

relevant management plans / works method statements (Appendix A), the most pertinent being:

• Keltbray Remediation – Enabling and Remediation Works – KREM-6068-PMS-001;

• Keltbray Remediation – Excavation Activities – KREM-6068-TSMS-001;

• Keltbray Remediation – Obstruction Removal – KREM-6068-TSMS-001-00;

• Keltbray Piling – Steel Sheet Pile Installation with Kowan WP150 Tosa – KSP-SP4108-MS-001; and

• Keltbray Remediation – Phasing Plan – V1-BX-KRE-X-000-XX-DR-CE-0003 to 14.

During periodic site inspections (Appendix B), BuroHappold observed enabling / earthworks to be undertaken in

general accordance with the above method statements, with no evidence of environmental nuisance or hazard. Good

construction practice and housekeeping ensured that the potential risks to construction workers and site neighbours

associated with the potential for presence of hazardous materials in Made Ground was appropriately managed and

mitigated. Dust suppression methodologies were in place and observed throughout the earthworks, as documented in

the site inspection notes (Appendix B). Both Morgan Sindall and Keltbray have confirmed that no relevant incidents

were recorded.

6.3 Earthworks

6.3.1 Excavated soils

6.3.1.1 Keltbray Piling

Prior to bulk excavation, Keltbray Piling constructed permanent sheet piles to support the basement dig. All the works

completed to enable this piling (i.e. tree stump removal, excavation of a leader trench and associated spoil removal)

were undertaken by Keltbray Remediation (see below).

6.3.1.2 Keltbray Remediation

Keltbray Remediation were responsible for: (i) tree stump removal, (ii) completion of a leader trench to 3m begl to

identify obstructions ahead of sheet piling works, (iii) placement of piling mat and (iv) the bulk excavation necessary

for the basement construction / to reach the specified formation level. Prior to bulk excavation, Keltbray undertook a

trial pitting exercise for waste classification purposes – the location of these trial pits and associated chemical data are

provided in Appendix C. This exercise identified Made Ground generally to a shallower depth than expected and with

relatively few anthropogenic inclusions.




The approach to the bulk excavation was to divide the site into two areas (Area A and Area B). The excavation was first

undertaken in Area B, which was handed over to the substructure contractor (FDL) on completion, before being

progressed in Area A - see Figure 6-1 and Keltbray Phasing Plan (Appendix A).

Figure 6-1 - Areas A and B within the Britannia School site, excerpt from Keltbray Phasing Plan (Appendix A).

Throughout these works, BuroHappold observed appropriate stockpiling of Made Ground (Figure 6-2) and natural

strata in accordance with the Remediation Scheme [1], the Materials Management Plan [11] and Keltbray’s Phasing

Plan (Appendix A). Very little visual or olfactory evidence of contamination and very few anthropogenic components

(aside for cobbles of concrete / brick) were encountered. Keltbray attempted to use a screener with meshes to identify

granular Made Ground of suitable clast size for use as structural fill. However due to high fines content of the material

and programme / space constraints, no material was reused, and all excavated spoil was suitably removed from site.

Confirmatory sampling and chemical analysis were undertaken from these stockpiles to support waste classification

(data provided in Appendix C).

Keltbray Remediation removed 1006 loads (~9095m3 based on assumed loads of 9m3) of spoil from site between

31/05/2019 and 09/09/2019 – with final handover to FDL on 13/09/2019. The end destinations, classification and

volumes removed from site are summarised in Table 6-1 and reproduced in full in Appendix C. During the periodic site

inspections, BuroHappold observed the correct transfer of data from the Waste Transfer Notes to the maintained

export log (see Appendix B). Samples of these Waste Transfer Notes are also provided in Appendix C.




Table 6-1 - Material removed from site by Keltbray Remediation.

End destination [permit. no] EWC code Volume (m3)

Ferry Lane, Rainham [WML80378] 17-09-04 – Mixed construction & demo. waste / 17-02-01 - Wood 86 / 30

Hamstow Wharf, London 17-09-07 – Mixed metals 4

Plaistow Wharf, London [CP3902KF/A001] 17-01-01 - Concrete 513

Powerday, Brixton [JB3637RK/T001] 17-04-07 – Mixed metals 24

SRC, Barking [EB3602UW] 17-01-01 – Concrete 189

Sydenham Gasholders [CB3902KF/A001] 17-05-04 – Soil and stones 6444

Veolia, Rainham [EP3136GK] 17-05-04 – Soil and stones 1809

Total: 9095

Figure 6-2 - Stockpile of Made Ground (07/08/2019). Material

held on site but no attempt to screen fractions suitable for

reuse being undertaken.

Figure 6-3 - Screener present 22/08/2019, removed by

following visit (05/09/2019).

6.3.1.3 FDL

FDL undertook relatively limited earthworks, having received Areas A and B at formation level with structural fill

already placed as required (see section 6.3.2). Any excavation principally related to construction of crane bases, lift pits,

and removal of material used to construct site access ramps. Throughout periodic site inspections, BuroHappold

observed appropriate excavation, segregation and stockpiling of material. In general, waste classification was based on

the data obtained by Keltbray. Since much of the material excavated by FDL was natural strata or used structural fill

(imported by Keltbray), further chemical testing was not undertaken / required.

FDL removed 155 loads (~1395m3 based on assumed loads of 9m3) of spoil from site between September 2019 and

February 2020. The end destinations, classification and volumes removed from site are summarised in Table 6-2. FDL’s

summary of material removed from site and samples of Waste Transfer Notes are provided in Appendix D. Waste

Transfer Notes were available for inspection over the course of the works.




Table 6-2 - Material removed from site by FDL.

End destination [permit. no] EWC code Volume (m3)

DB Schenker Rail Ltd, Pudding Mill Lane [EPR/BP3698EQ] 17-05-04 – Soil and stones 1287

Brocks Haulage Limited, Watson Close, West Thurrock [EAWML/71500] 17-01-01 - Concrete 108

Total: 1395

Figure 6-4 - Site overview on 05/09/2019, central stockpile of

Made Ground being worked by FDL.

Figure 6-5 - Example of FDL excavation / substructure

construction in natural ground (23/09/2019).

6.3.2 Imported material

6.3.2.1 Keltbray Remediation

Keltbray’s complete records of material import are provided in Appendix C. Material classified as 6F5 was imported to

form the piling mat during June-July 2019 (Figure 6-6). This material was originally placed in Area B and then reused in

Area A. Material classified as 6F5 was also imported for use as structural fill for the underside of the raft foundation

[Note: This was because the Made Ground encountered was unsuitable / impractical to reuse as originally planned

(Figure 6-7). Import for Area B was approximately between August and early September 2019, and for Area A in mid-

September 2019. An asbestos screen was undertaken on this imported material at a rate of 1 sample per 500m3. The

analyses did not record the presence of any asbestos containing materials and are provided in Appendix C. The

volumes and sources of import are summarised in Table 6-3 below.

Table 6-3 - Summary of Keltbray import.

Source Material type Volume (m3)

DAY Aggregates, Murphy’s Wharf, Lombard Wall, Charlton, SE7 7SH 6F5 / Type 2 117 / 9

Recycled Material Supplies Ltd, Sunshine Wharf, Bradfield Road, E16 2AX 6F5 171

SRC Group, Barking Riverside Main Entrance, Barking, IG11 0YN 6F5 2781

STEMA, Alexandra House, Lakeside, Grays, Essex, RM20 1WL Type 1 144

Total 3282




Figure 6-6 - Piling mat placed along eastern boundary

(10/07/2019).

Figure 6-7 - Imported 6F5 structural fill placed on River

Terrace Deposits (05/09/2019). Excavation was to 300mm

below underside of slab, to allow build-up of subbase

beneath the raft foundation. No Made Ground was reused for

this purpose.

6.3.2.2 FDL

FDL imported 4 loads of 6F2 (60m3) and 7 loads of Type 1 (105m3) for backfill behind the retaining wall on the north

elevation of the site (along Hyde Road). Two samples of this material were subject to asbestos screen testing. The

analyses did not record the presence of any asbestos containing materials and the data are provided in Appendix D.

The volumes and sources of import are summarised in Table 6-4 below.

Table 6-4 - Summary of FDL import.

Source Material type Volume (m3)

O’Donovan Waste Disposal Depot, Markfield Road, Tottenham, N15 4QF 6F2 / Type 1 60 / 105

Total 150

6.3.3 Compliance with Materials Management Plan

As described in Section 5.3.1, a Materials Management Plan was prepared for the Phase 1B area to enable use of site-

won Made Ground soils in place of imported structural fill to bring ground elevation up to formation level. However,

also as previously described (Section 6.3.1.2) due to the high fines content of the material and programme / space

constraints, no Made Ground soils were reused and all structural fill was imported. The MMP stated that up to 2991m3

of Made Ground would be treated, placed and compacted – however a total of 3069m3 of 6F5 was instead imported

for this use. Similarly, the MMP states that approximately 6970m3 of surplus spoil would be sent off site for treatment /

disposal. This implies a total excavation volume of about 9961m3, which broadly corresponds with the total volume of

soils removed from site of 10490m3. BuroHappold observed this removal of Made Ground from site and import of 6F5

over two days of full-time site attendance (05/09/2019 and 06/09/2019), see Appendix B.

6.4 Groundwater management

No groundwater was encountered during the earthwork activities.




6.5 Below ground infrastructure

The appropriateness of the design of the below ground concrete as detailed in the Remediation Scheme [1, 2]

(minimum DC3 / AC2S) has been demonstrated by the supplier’s certification records, provided in Appendix E.

The layout of potable water supplies is shown by a drawing provided in Appendix E. Potable water supply used

Polyguard (barrier pipe) where potable water supply was placed in Made Ground.

6.6 Unexpected contamination

During the periodic site inspections carried out by BuroHappold, Morgan Sindall / Keltbray / FDL reported no

occurrences of encountering unexpected contamination. Across the Phase 1B area, Made Ground was generally

encountered to a shallower depth than anticipated and free of visual / olfactory evidence of contamination.

6.7 Environmental monitoring

The Remediation Scheme identified a requirement for air monitoring in the event that significant amounts of ACMs

were identified. Consequently, no environmental monitoring was undertaken over the duration of the earthworks.

However, as noted in Section 6.2, good construction practice including dust suppression measures was adopted.

6.8 Independent inspection

6.8.1 Periodic site inspections

BuroHappold undertook nine site inspections between May and November 2019. These inspections were timed to

observe key aspects of the initial enabling works through to construction of the substructure. This was supplemented

with two days of full-time site attendance (05/09/19 and 06/09/19) to witness the placement of imported structural fill

as opposed to the reuse of Made Ground intended by the approved Materials Management Plan [11]. Throughout

these inspections, BuroHappold found the site to be in good working order with appropriate environmental

management in place. The records of these site inspections are presented in Appendix B.

6.8.2 Ad hoc advice

No ad hoc requests for advice were made by Morgan Sindall or sub-contractors due to encountering unexpected

contamination during the earthworks process.

6.8.3 Liaison with local authority

No liaison with the local authority was required or carried out.




7 Conclusions

7.1 Achievement of remedial objectives

The Remediation Scheme [1] and Phase 1B Addendum [3] (summarised in Chapter 4) have been successfully delivered

and the remediation objectives achieved with respect to the groundworks elements of the work on Phase 1B.

1. Workers engaged in the redevelopment have not been exposed to contamination in the solid, liquid or

gaseous/vapour phase at concentrations that could give rise to acute risks;

2. Site neighbours have not been exposed to contamination in dusts at concentration that could give rise to

acute risks;

3. The quality of groundwater resources (Secondary Aquifer) has not been significantly impacted by any

potentially mobile inorganic or organic contaminants in both the short and long terms;

4. The redeveloped Phase 1B site is most unlikely to be determined as ‘Contaminated Land’.

5. Relevant building materials (below ground concrete and water supply pipework) are designed not to be

subject to chemical degradation;

6. No preferential pathways for migration of contamination have been created.

7.2 Compliance with remediation strategy

The contractors engaged with the enabling earthworks (Keltbray / FDL) managed excavated soils suitably, with

appropriate segregating, stockpiling and testing of the material to enable classification for appropriate disposal. All

soils were removed from site as either inert or non-hazardous waste, with supporting tickets held.

7.3 Compliance with Materials Management Plan

A Materials Management Plan was prepared for the Phase 1B site area to enable up to 2911m3 of Made Ground spoil

to be reused in place of imported structural fill. Due to the high fines content of the Made Ground soils and space /

programme constraints, no Made Ground was reused and 6F5 fill was instead imported. This is substantiated by the

records of material import and disposal and was independently verified by BuroHappold over two days of full-time site

attendance.

7.4 Status of site at completion of works

This report (Verification Report – Part A) forms part of a two-part Verification process. A later report (Part B –

Landscaping) will be submitted on completion of the placement of imported topsoil / subsoil within soft landscaped

areas / planters as set out in Chapter 5 of the Verification Plan [3].

Based on the above, it is concluded that the provisions of the local authority Planning Condition 20 has been met

(reflecting the implementation of the Remediation Scheme). This report presents the evidence demonstrating the

effective implementation of the agreed remedial strategy with respect to Part A – Earthworks on Phase 1B.

Accordingly, this report should be submitted to the local authority for their consideration with respect to discharge of

this condition relevant to Part A – Earthworks on Phase 1B.




References

[1] BuroHappold Engineering, “Site-wide Remediation Scheme. 0036399-BHE-XX-XX-RP-YG-0005.,” 2019.

[2] BuroHappold Engineering, “The Britannia Project - Phase 1B Remediation Addendum. 0042977-BHE-XX-XX-DN-

YG-0001,” 2019.

[3] BuroHappold Engineering, “The Britannia Project. Phase 1B (Secondary School) Verification Plan.,” 2019.

[4] Environment Agency, “Model Procedures for the Management of Land Contamination - Contaminated Land

Report 11 (CLR11),” 2004.

[5] gov.uk, “Land contamination: risk management,” 2019 December 23. [Online]. Available:

https://www.gov.uk/guidance/land-contamination-how-to-manage-the-risks. [Accessed 03 February 2020].

[6] SocoTec UK Limited, “Britannia Leisure Centre, Hackney - Factual Report on Ground Investigation,” 2018.

[7] SocoTec UK Limited, “Britannia Project, Hackney - Factual Report on Ground Investigation,” 2017.

[8] BuroHappold Engineering, “Remediation Assessment and Spoil Management,” 2019.

[9] Ministry of Housing, Communities & Local Government, “National Planning Policy Framework,” Ministry of

Housing, Communities & Local Government, 2019.

[10] BuroHappold Engineering, “The Britannia Project. Specification for Earthworks. T5073-ZZ-BHE-XX-SP-C-9010.,”

2018.

[11] BuroHappold Engineering, “The Britannia Project. Materials Management Plan. 0042977-BHE-XX-XX-RP-YG-

0009.,” 2019.

[12] BuroHappold Engineering, “Project Specification for Piling and Embedded Retaining Walls. TP5073-ZZ-BHE-XX-

SP-C-9000,” 2019.

Documents

The Britannia Project Phase 1B