Arup Method Statement

Infrastructure & Public Realm Works Work Method Statement February 2012

Meridian Delta Limited Greenwich Peninsula Infrastructure and Public Realm Works Peninsula Quays Zone A Public Realm Works Method Statement (Planning) EMS/WMS(P)/PQA/REP001 Issue 1 | 29 February 2012

This report takes into account the particular instructions and requirements of our client. Ove Arup & Partners Ltd 13 Fitzroy Street London W1T 4BQ United Kingdom www.arup.com

It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party.

Job number

068006-18

Document Verification Job title

Document title

Greenwich Peninsula Infrastructure and Public Realm Works

Job number

Peninsula Quays Zone A Public Realm Works Method Statement (Planning)

File reference

Document ref

EMS/WMS(P)/PQA/REP001

Revision

Date

Filename

PQ Zone A WMS(P) Draft1.docx

Draft 1

25 Feb 2012

Description

First draft

Name

068006-18 18.44

Prepared by

Checked by

Approved by

Chris Kitley

Richard Owen

Richard Owen

Signature

Issue 1

29 Feb 2012

Filename Description

Name

PQ Zone A WMS(P) Issue 1 Draft Agreed.docx Draft Agreed for EMS Approval

Prepared by

Checked by

Approved by

Chris Kitley

Richard Owen

Richard Owen

Prepared by

Checked by

Approved by

Prepared by

Checked by

Approved by

Signature Filename Description

Name Signature Filename Description

Name Signature Issue Document Verification with Document

EMS/WMS(P)/PQA/REP001 | Issue 1 | 29 February 2012 J:\68000\68006 MERIDIAN DELTA, GREENWICH\18 AD HOC CONSULTING\18.44 ZONE A PUBLIC REALM (AND AEG AND HOTEL ACCESS\PQ ZONE A WMSP\PQ ZONE A WMS(P) ISSUE 1 DRAFT AGREED.DOCX



Meridian Delta Limited

Greenwich Peninsula Infrastructure and Public Realm Works Peninsula Quays Zone A Public Realm Works Method Statement (Planning)

Contents Page

1

2

3

4

Introduction

1

1.1 1.2 1.3 1.4 1.5

1 1 1 2 2

Background Scope Objective of this document Proposed development Document Status

Existing conditions

3

2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

3 3 4 5 6 8 9 9

General Site description Site history summary Geology and hydrogeology Ground conditions Existing remediation systems Existing utilities Unexploded ordnance

Development proposals

11

3.1 3.2 3.3 3.4

11 12 12 13

General Earthworks Remediation and earthworks philosophy EMS procedures

Environmental monitoring

17

4.1 4.2

17 17

Construction monitoring Groundwater monitoring

Figures Figure 1 Figure 2 Figure 3 Figure 4

Site location plan Current Site Layout Plan Ground investigation locations Remediation excavations and historical ground investigation locations

Appendices Appendix A




Landscape Masterplan Appendix B Scheme Design Information Appendix C Historical Remediation Information Appendix D Environmental Risk Assessment Appendix E Location of Long Term Groundwater Monitoring Wells



1

Introduction

1.1

Background


All construction work that is undertaken by developers on Greenwich Peninsula under the planning permission granted by the London Borough of Greenwich (LBG) to Meridian Delta Limited (MDL), the Homes and Communities Agency (HCA) formerly the Urban Regeneration Agency (as English Partnerships)), AEG Dome Arena Limited, and Quintain Estates & Development plc, and which disturbs the ground, is required to follow the Environmental Method Statement (EMS) procedures. The EMS for all of the land was prepared by Atkins and was submitted to the LBG to discharge Outline Planning Condition 97 on December 14, 2004 (OPP reference 02/2903/O) and resubmitted in November 2008. LBG confirmed acceptance of the EMS, and discharge of Condition 97, by their letter dated 23 February 2005. The EMS forms part of the Integrated Management System (IMS) for the re-development of Greenwich Peninsula, as required by clause 41 of the Section 106 Agreement. The EMS has been revised a number of times and the latest approved version is document reference AC1787/D2/6325Rev 5, dated February 2011) 1.

1.2

Scope

This Works Method Statement (Planning) (WMS(P)) has been prepared by Ove Arup & Partners Limited (Arup) on behalf of MDL (the Applicant) in support of the hybrid planning application to Greenwich Council which comprises detailed planning permission for the infrastructure and public realm works surrounding Plots N0601, N0608 and N0506 including revised vehicle access routes to Plot N0301 (AEG Hotel) and the O2 Arena (Dome). This area is collectively referred to as the Peninsula Quays Zone A infrastructure. The hybrid planning application also includes an outline planning application for Plot N0506. Since the N0506 element of the planning application does not fall under the existing outline planning permission, a WMS(P) for N0506 is not required. However, assuming permission is granted and a condition to comply with the EMS is imposed (as is expected), a WMS(P) for the plot will be completed for the detailed application. Therefore, this document only presents the WMS(P) for the Peninsula Quays (PQ) Zone A infrastructure area. A plan showing the red line boundary of the site is presented in Figure 1. This document has been prepared to discharge Conditions 88 (Remediation Strategy) and 97 (Environmental Method Statement) of the detailed planning permission of the hybrid planning submission.

1.3

Objective of this document

This WMS(P) is prepared for the purposes of compliance with the EMS (and IMS) and will form part of the information to be submitted with the planning 1

Atkins. Greenwich Peninsula Environmental Method Statement. Volume 1 and 2. Revision 5. Document Reference AC1787/D2/6325. February 2011. EMS/WMS(P)/PQA/REP001 | Issue 1 | 29 February 2012 J:\68000\68006 MERIDIAN DELTA, GREENWICH\18 AD HOC CONSULTING\18.44 ZONE A PUBLIC REALM (AND AEG AND HOTEL ACCESS\PQ ZONE A WMSP\PQ ZONE A WMS(P) ISSUE 1 DRAFT AGREED.DOCX

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application for the PQ Zone A site. The objective of this WMS(P) under the EMS system is as follows: 

To outline the existing ground conditions and any previously installed remediation systems.



To outline the development proposals, design philosophy and mitigation measures.



To present an environmental risk assessment.



To identify potential environmental issues that may arise as a direct result of the proposed development.



To discuss the requirements for operational and long term monitoring.

1.4

Proposed development

The proposed development works undertaken on PQ Zone A public realm are outlined below. The landscape architect’s masterplan for the area is presented in Appendix A. 

Development of the public realm around Plots N0601, N0608 and N0506 (comprising Meridian Gardens adjacent to the Thames, Ice House Way, Draw Dock Road, the northern end of Tunnel Avenue and part of Ordnance Crescent and Millennium Way) and for the Hotel Approach Road and AEG Service Access Road.



The public realm works comprise construction vehicle access roads, landscaping, tree planting, intimate gardens, cycle routes and walkways, a climbing wall and outside gym equipment.



The infrastructure works comprise surface and foul drainage and service corridors for utilities and a combined heat and power network. An attenuation tank is proposed under the Meridian Gardens area of the site.



Construction of a retaining wall to the south of the Hotel Access Road to enable the construction of the Hotel Access Road on higher ground to the north. Another retaining wall will be required around the southern extent of the Dome Access Road.



A temporary marketing suite is proposed at the end of Ice House Way near the river that could have an alternative use e.g. a riverside café once it is no longer required

1.5

Document Status

Arup has been appointed by MDL to prepare this WMS(P) for the purposes of compliance with the EMS (and IMS) and as part of the information to be submitted to LBG for the detailed planning conditions 88 and 97 for the PQ Zone A infrastructure and public realm.


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2

Existing conditions

2.1

General

The general geological and hydrogeological conditions across the HCA-owned land, and the history of remediation undertaken at the site, is outlined in Part A of Volume 2 of the EMS. To supplement pre-existing information, detailed desk studies have been undertaken for the Peninsula Quays site and various phases of ground investigation have been undertaken across the different areas of the site. The desk studies and previous site investigations are included in the following reports: 

Arup. Works Method Statement (Planning). Peninsula Quays Access Land – Phase 1b, Phase 2 and Phase 3 Sitewide Highway Works. Issue 1 Agreed, April 2008.



Arup. Works Method Statement (Planning) – Meridian Gardens Central Infrastructure Works. Issue 5 Agreed. July 2007.



RPS. Meridian Gardens North, Greenwich Peninsula Infrastructure & Regrading Factual Geo-Environmental Site Investigation Report. August 2006.



RPS. Meridian Gardens North Greenwich Peninsula West, London. Environmental Desk Study. November 2006.

Outline descriptions of the present ground conditions and of the exisiting remediation systems across parts of PQ Zone A are provided below.

2.2

Site description

A aerial photograph showing the current land use on the PQ Zone A area is presented in Figure 2. Currently the site includes: 

The western area of PQ Zone A. This is the largest area of Zone A and is currently used for stockpiling site won soil material from other development works on Greenwich Peninsula. A BAM compound is also located in this area adjacent to the Blackwall Tunnel vent shaft;



Existing roads: the current route of Drawdock Road, the northern end of Tunnel Avenue and part of Ordnance Crescent and Millennium Way, with associated pedestrian paving and grassed embankments; and



The current AEG service road and AEG compound to the south east of the O2 dome.

Current site levels are variable due to the presence of stockpiles within the PQ area of the site, and the presence of an embankment between Draw Dock Road and the current route of the AEG Access Road. The levels range between +2m OD and +6m OD. The levels adjacent to the river wall on the western side of Zone A are approximately +5m OD and reduce to +2m OD to the east of Tunnel Avenue (allowing for localised high points associated with the stockpiles on this area).


Page 3


2.3


Site history summary

The potential for ground contamination to exist at a site is closely linked to its past uses, particularly if those uses have been industrial or commercial. The PQ Zone A site covers two areas of land which were referred to in the Environment Statement for Greenwich Peninsula as the ‘Western Development Area’ and the ‘Millennium Exhibition Site’ (now referred to as the HCA land). The location and boundary of these areas is presented below. Areas of Greenwich Peninsula discussed in the Environmental Statement with approximate site boundary.

The history of the land associated with the Millennium Exhibition Site (HCA Land) is summarised below 

This area of land was occupied by one of the largest gasworks in Europe from the early 1900s up until the 1970s. The gasworks complex had a range of associated industries, including a large tar works, a chemical works for the manufacture of sulphuric acid and ammonium sulphate fertiliser, and a power station. The generation of coal gas and associated by-products were undertaken on the site for nearly 80 years.



The HCA land within and adjacent to the PQ Zone A included tar acid plants, a naphthalene plant, a naphthalene house and workshops and stores. Notably, a a area containing numerous tar tanks and a large tar wall was located approximately 100m north of the northern boundary of PQ Zone A. Details on the historical gasworks infrastructure in this area is presented in Appendix C.



Following the industrial use of the site, the Millennium Exhibition land was subject to two phases of remediation. These stages were:


Page 4





‘Statutory Remediation’, undertaken by Port Greenwich Limited (British Gas plc) in 1996/97; and



‘Development Remediation’, undertaken by EP during the period 1997 – 1999.

Details of the remediation works undertaken on the Millennium Exhibition site are discussed further in Section 2.6. The Western Development Area, which makes up the majority of the PQ Zone A area has also had a long and complex history of industrial uses, and over the period from 1869 has been occupied by a shipbuilding yard, large metal works, oil mills, ice works, asbestos works, chemical works, wood paving works, a linoleum factory and demolition waste handling operations. No statutory or development remediation works were undertaken on the Western Development area. During the 1960’s the northern part of Peninsula Quays was occupied by the Delta metal works. From the 1990s until about 2002 to 2004, the northern end of the Peninsula Quays was occupied by a marine aggregates processing plant, a cement batching plant and a demolition waste sorting operation. Since that time the area has been vacant (except for the storage of stockpiled soil material).

2.4

Geology and hydrogeology

The sequence of strata at PQ and depths and typical thickness of the strata as revealed by the previous ground investigations, are given in Table 1 below. Table 1. Assumed geological sequence at Peninsula Quay Strata

Elevation (top of strata) mOD

Typical Thickness (m)

Made Ground

Ground Level

2m

Alluvium Clay

+4.0m to -0.2m

3m

Alluvium Peat

+0m to -1.35m

1m

River Terrace Deposits

-1.37m to -2.4m

6.5m

London Clay

-7.67m to -9.57m

15m

Lambeth Group

-13.57m to -26.11m

6.5m to 16m

Thanet Sand

-28.37m to -30.01m

Not proven

Notes: Based on a summary of the stratigraphy for Peninsula Quays presented in previous WMS(P)2 repots. Stockpiles of site won materials are also present across the surface on Peninsula Quays. These are not included in the elevation or thickness details of the Made Ground. Made Ground will also include various concrete obstructions that have been identified on Peninsula Quays.

2

Arup. Greenwich Peninsula Re-Development. Works Method Statement (Planning) - Peninsula Quays (formerly Meridian Gardens) Infrastructure Works. Issue 5 Agreed 22/11/07. EMS/WMS(P)/PQA/REP001 | Issue 1 | 29 February 2012 J:\68000\68006 MERIDIAN DELTA, GREENWICH\18 AD HOC CONSULTING\18.44 ZONE A PUBLIC REALM (AND AEG AND HOTEL ACCESS\PQ ZONE A WMSP\PQ ZONE A WMS(P) ISSUE 1 DRAFT AGREED.DOCX

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The hydrogeological conditions beneath the HCA land on Greenwich Peninsula are outlined in Part A of Volume 2 of the EMS. Three hydrogeological units are identified, as follows: 

Perched water. This is discontinuous water within the Made Ground. Where present, it occurs at the base of the Made Ground ‘perched’ on the underlying low permeability Alluvium layer, or occasionally at a higher level ‘perched’ on lenses of lower permeability Made Ground, or buried structures. Perched water is not a ‘Controlled Water’ and therefore is not regarded as a water resource by the Environment Agency.



River Terrace Deposits (RTD) secondary aquifer. Groundwater is present within the RTD and it is a Controlled Water, classified as a water resource by the Environment Agency.



Chalk and Basal Sands Aquifer. At depth groundwater is present within the Upper Chalk and the overlying Thanet Sands Formation and lower sandy members of the Lambeth Group, which are hydraulically connected. The Chalk is classified as a principal aquifer and the Thanet Sands Formation / Lambeth Group as a secondary aquifer. The clay strata within the Lambeth Group will act as an aquitard, hydraulically separating the Chalk - Basal Sands and RTD aquifers.

The River Thames which loops around Greenwich Peninsula is the primary hydrological feature in vicinity of the Site. Long term groundwater monitoring is undertaken across Greenwich Peninsula, as discussed in Section 2.5 below.

2.5

Ground conditions

A summary of the investigations undertaken in different parts of PQ Zone A (is given in Table 2 below and a composite plan all the investigation locations is included as Figure 3. Table 2. Summary of site investigation report on or in the vicinity of the northern end of Peninsula Quays Zone A Prepared By:

Prepared For:

Title

Date (of report)

Summary Scope

RPS

Quintain Estates & Development

Blackwall Aggregates Preliminary Site Investigation KE2060027R

May 1999

5 BHs, 3 WS boreholes

Atkins

Not Known

Not known

1999

3 BHs

RPS


Blackwall Aggregates Environmental Site Investigation LI5186074R

March 2000

14 Trial Trenches

RPS


Meridian Delta Supplementary Environmental Site Investigation LI5186075R

January 2001

14 BHs

Quintain

Former Blackwall

RPS


Page 6


Prepared By:


Prepared For:

Title

Estates plc

Aggregate and Hennelleys Site – Groundwater Assessment Report, FLI1498/022R

Quintain Estates plc

Former Blackwall Aggregate and Hennelleys Site Environmental Summary Report FLI1498/024R

RPS


RPS

RPS

RPS

Date (of report) April 2005

Summary Scope

April 2005

Desk Study

Greenwich Plot N0601 Factual GeoEnvironmental Site Investigation Report, HLC0593/035R

August 2006

1 BH, 3 TPs


Greenwich Plot N0608 Factual GeoEnvironmental Site Investigation Report, HLC0593/039R

August 2006

1 BH, 3 TPs


Meridian Gardens North – Environmental Desk Study HLC0593/046R

November 2006

Desk Study

4 BHs

No recent ground investigations have been undertaken on the infrastructure corridors around Plot N0506 or along the Hotel Access Road and the AEG Service Road. Historical ground investigation has been undertaken as part of the remediation works on these areas of land. The locations are also presented on Figure 3 although the factual report and borehole logs are not available for these investigations. The investigations indicate that the Made Ground is not significantly impacted by contamination, except for occasional localised hotspots. Much of the Made Ground that will be excavated for future development may be suitable for re-use. The shallow perched groundwater is impacted by contamination, but this has not been found to be severe. The Alluvium is not significantly contaminated however there are peat layers to the base of the stratum, which are a source of methane and carbon dioxide (as found elsewhere on Greenwich Peninsula). The RTD soil quality and the water quality of the groundwater contained within this deposit are not significantly impacted by contamination, except along the northern and north-western edges of Peninsula Quays. In this area there is heavy dissolved phase and free phase hydrocarbon contamination present, which is interpreted as most likely having migrated from the former tar tank areas to the north on Peninsula Quays. A detailed assessment of the ground conditions presented in the site investigation reports will be included in the Works Method Statement (Design).


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2.6


Existing remediation systems

As mentioned in Section 2.3, remediation works have been carried out across the ‘Millenium Exhibition’ (HCA Land) area of PQ Zone A. No remediation works have been undertaken on the ‘Western Development’ area of the site. The extent of the remediation works previous undertaken on the HCA land is summarised below.

Statutory Remediation The statutory remediation works were designed to remove the major source areas of contamination. This was largely achieved by excavation and disposal of heavily contaminated soils off-site to landfill. However it also included in-situ remediation of benzene contamination by dual-phase groundwater and soil vapour extraction and the very deep excavation of a large diameter bomb-damaged tar well in two areas at the northern end of the peninsula (to the north of PQ Zone A). The extent of the statutory remediation dig area at the northern end of the peninsula is illustrated on Figure 3 of this report. Further information on the statutory remediation is presented in Appendix C. There is the potential for residual contamination to be present at the edge or below the former remediation dig at the northern end of the Hotel Approach Road.

Development Remediation Following English Partnership’s purchase of land on the northern and eastern side of Greenwich Peninsula from British Gas in 1997, it was necessary to supplement elements of the statutory remediation scheme in order to prepare the land for the Millennium Exhibition, and some areas for their long term use. The development remediation (and site enabling) works were completed under a number of contracts and in summary comprised the following: 

Demolition of buildings and removal of foundations and slabs to a depth of 1m below the 1998 initial and final re-graded ground levels, across the whole area.



Re-grading of the site, including scarifying the near-surface layer to remove obstructions, and excavation and removal (disposal off-site) of contaminated ground from localised hotspots encountered during the enabling earthworks.



Construction, across the whole site, of a clean surface capping layer to prevent direct contact with potentially contaminated ground, and upward migration of potential contaminants from the underlying ground to the surface. A brightly coloured, permeable plastic ‘marker sheet’ was placed at the base of this layer to delineate the boundary of the clean layer and the underlying (potentially locally contaminated) ground. The nature of the clean capping layer was different depending on the use of the area for the Millennium Exhibition (public hard landscaping, soft landscaped areas, car and coach parking).



The capping system in roadways comprised a marker layer placed on the existing ground, overlain with 450 mm depth of clean hardcore. Road build-up is on top of this typically 200 mm thick of clean backfill or cement bound material overlaid by ‘Fibredeck’. Note that cement/lime stabilisation of soft


Page 8



alluvium was used to improve the geotechnical properties below car parks and some roadways. 

The Dome area capping system consists of a marker layer placed on the existing ground, overlain with 450 mm depth of clean hardcore a fabric separator, 1mm LDPE gas membrane, sand blinding layer and concrete slab.



Provision of service corridors of clean soil for site wide services (electricity, water, gas, telecommunications), underlain and surrounded by a clay liner.



Installation of foul and surface water drainage with measures to prevent migration of contaminants and cross-contamination of clean and untreated ground.

The schematic details of the development remediation are presented below and discussed in Volume 1 of the EMS.

2.7

Existing utilities

Details of the existing utilities are presented on the scheme design plans presented in Appendix B.

2.8

Unexploded ordnance

A report by BACTEC International Ltd was commissioned by Port Greenwich Ltd in 1996 to examine the threat by bombs and ordnance to the larger Greenwich Peninsula development site. The impact location map included in the BACTEC report shows selected bomb strikes identified from documentary sources. While this report did not specifically include the Peninsula Quays area the impact location map shows approximately nine hits within the PQ area. An additional UXO report by BAE Systems Environmental was commissioned for the Greenwich Peninsula Development by Atkins on behalf of MDL in September 2006. The report examined the potential risk to site investigation and development works on the wider MDL development site, and the potential for risk mitigation measures to be required. The BAE Systems report concluded that the potential zone of influence for the site was the upper 8m of undisturbed ground and the western part of the PQ Zone A area was classified with a low to moderate likelihood of UXO remaining after WWII. The eastern and area of PQ Zone was classified with high risk however, as shown below. EMS/WMS(P)/PQA/REP001 | Issue 1 | 29 February 2012 J:\68000\68006 MERIDIAN DELTA, GREENWICH\18 AD HOC CONSULTING\18.44 ZONE A PUBLIC REALM (AND AEG AND HOTEL ACCESS\PQ ZONE A WMSP\PQ ZONE A WMS(P) ISSUE 1 DRAFT AGREED.DOCX

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Plan of high risk areas (shaded in red) as presented in the BAE Systems Report (2006).


Page 10



3

Development proposals

3.1

General

The scope of the public realm and infrastructure development in PQ Zone A has been outlined in Section 1.4. The landscape masterplan is presented Appendix A and plans of the infrastructure development are presented in Appendix B. In summary the proposed development works along each of the corridors is as follows. Table 3. Summary of the PQ Zone A public realm development works. Meridian Gardens

The majority of this area will be public realm with a hard landscaped cyclepath and footpath located adjacent to the river wall on the western site boundary. Intimate garden spaces are included in the western side of Plot N0601, which will include soft landscaping, an informal adventure play area for toddlers and planting of cherry trees. An ornamental maze will also be includes in the soft landscaping works. A marketing suite building may be constructed on the southern end of the Meridian Gardens area which could be used as a cafe in future, following completion of the development. The infrastructure services in this area includes surface water drainage, an attenuation tank, outfalls to the River Thames and service corridors for low voltage electricity cables, potable water pipes and telecoms ducts.

Ice House Way

This is a mixed vehicle and pedestrian route with limited car parking spaces. The route will be lined with trees, placed within tree pits. The infrastructure will include surface and foul water drainage and services corridors for water, telecoms, gas, electricity and combined heat and power.

Delta Strand

Delta Strand, between N0601 and N0608 will be constructed over the joint basement between the two plots. This route will be considered under a separate application and therefore is not considered in this report..

Draw Dock Road

This is a mixed vehicle and pedestrian route, linking with the Draw Dock slipway to the west. The infrastructure services will include surface water drainage and services corridors for water, telecoms and electricity supply.

Tunnel Avenue

This area will be modified from its current highway use to include a mixed vehicle and pedestrian route with some landscaping features (trees within pits and some ground cover planting). The tree planting will include cherry trees and external gym equipment and a rock climbing/traversing wall is proposed for the northern end of the route.

Hotel Approach Road and AEG Service Access Road

This area will principally comprise vehicle access routes to the Hotel and the AEG service areas. The routes will be tree lined and a pedestrian footpath will be present along the top of the retaining wall which will be constructed as part of the development. In addition, minor alterations to the roundabout at the northern end of Millennium Way and the public realm to the north of the bus turning area will be required. Service corridors and surface water drainage will be included in the infrastructure below the vehicle access roads


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3.2


Earthworks

Cross sections through the site are presented in Appendix B. These show the current ground level and the proposed formation levels within the public realm corridors. Earthworks fill will be required across the majority of Meriden Gardens and Ice House Way to raise ground levels. Ground levels will be raised by approximately 1.0 to 1.5m adjacent to the river wall using the existing stockpiled soils presently situated on the Peninsula Quays site. The proposed ground levels will slope down to the east, with an area of cut required towards the eastern end of Ice House Way. The maximum cut required is approximately 1.5m. Along the proposed Hotel Approach Road and AEG Service Access Road, the proposed levels will generally require an earthworks cut of approximately 0.2 to 0.5m. However, a large fill area has been identified midway along the Hotel Approach Road, where the route crosses the current corner between Tunnel Avenue and Draw Dock Road. Deeper earthworks excavations will be required for the installation of the service corridors, surface and foul sewer and for landscaping, such as tree pits. Scheme design depths of the infrastructure elements are presented in Appendix B. Materials used in the earthworks re-profiling of the site will be sourced from both existing site soils (arising from site re-grading and excavation for services and foundations) and from imported select materials for particular purposes. All sitederived and imported earthworks materials will be required to meet the particular physical and chemical specification for their purpose. A site specific risk assessment approach has been used to establish chemical acceptance criteria to categorise site-won material into Suitable and Unsuitable Materials in the Arup Remediation Strategy Framework report3. These criteria will be described and presented in the WMS (Design). The chemical criteria are not intended for application in ‘non-standard’ land-uses such as gardens with fruit or vegetable cultivation, schools, playing fields, large areas of public open space (such as parkland) or commercial land-uses which are designed for children, such as crèche, playground or leisure facilities. Further work may be required to assess the appropriate criteria to be used for nonstandard end uses, such as the gardens, trees or informal play areas within Meridian Gardens or Tunnel Avenue. The details of any additional assessment will be presented in the WMS(D).

3.3

Remediation and earthworks philosophy

Remediation works will comprise the over-excavation of any heavily contaminated soil identified during ground investigation, or encountered within development excavations (“hotspot areas”). Similarly, any zones of heavily contaminated shallow (perched) groundwater will be removed during development. The depth of over-excavation of soils will be determined on a human health and environmental risk-assessment basis, taking into account the 3

Arup. Greenwich Peninsula Remediation Strategy Framework Report. AEC-SITEWIDE-REP01 Issue 1 dated 05/12/07 EMS/WMS(P)/PQA/REP001 | Issue 1 | 29 February 2012 J:\68000\68006 MERIDIAN DELTA, GREENWICH\18 AD HOC CONSULTING\18.44 ZONE A PUBLIC REALM (AND AEG AND HOTEL ACCESS\PQ ZONE A WMSP\PQ ZONE A WMS(P) ISSUE 1 DRAFT AGREED.DOCX

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nature and degree of contamination, and the form of construction and end use in the localised area in question. Any hotspot areas will be identified in the WMS(D). It is not considered necessary to install a plastic marker sheet beneath an engineered capping layer in the land associated with the Western Development area. This is consistent with the principles of the Remediation Strategy Framework. However, an upper capping layer will be placed and a marker sheet may be installed in any localised areas where significantly contaminated ground will remain beneath the capping layer Across the former Millennium Exhibition site (HCA land), the remediation strategy in infrastructure areas (i.e. non building plots) will include: 

A marker sheet installed beneath an engineered capping layer.



The provision of a capping layer consisting of either Landscape Material or Upper Capping Material, above General Fill Material as defined in the Remediation Strategy Framework Report.



The perforated ‘marker sheet’, separating the upper capping material from underlying potentially contaminated ground will be maintained across the whole site and will extend across the top of backfill to new foul and surface water sewers.



A 200mm capillary break layer above the ‘marker sheet’ in soft landscape areas only sufficient to prevent the capillary rise of moisture through the Landscape Material above.



Underground services will be laid in clean service corridors with, where necessary, a liner to restrict cross-contamination by the surrounding ground.



Measures to control potential lateral migration of contaminated perched groundwater installed within backfill to drainage trenches, and elsewhere, where this is necessary.



Rainfall infiltration into the ground (which could cause the build up of contaminated perched water) will be minimised by the provision of hard landscaping with piped surface water drainage, and soft landscaping underdrainage.

3.4

EMS procedures

3.4.1

General

The philosophy of the development works will include the remedial requirement of the EMS so that in carrying the development works the necessary remediation requirements will be included to prevent, minimise, remedy or mitigate the effects of any harm to the Environment as a result of any pre-development site conditions or off-site migration. Remedial requirements will be incorporated into the detailed design of the earthworks to ensure that the development does not pose additional risks to future site users and the environment, in accordance with the EMS Codes of Practice (EMS-COP), and confirms to the principles of the site wide Remediation Strategy Framework.


Page 13



The relevant EMS procedures which are relevant to the works described in this WMS(P) are presented below. 

EMS-EMP-01 Works Method Statement: the contractor will be required to prepare and submit a Works Method Statement Construction for the works in accordance with the EMS procedure.



EMS-EMP-02 Permit to Dig: the contractor will be required to prepare and submit the relevant application for the Permit to Dig for any works which may penetrate the ground and/or disturb the existing ground conditions in accordance with the EMS procedure.



EMS-EMP-03 Competent Authority Interface: the contractor will be required to give reasonable notice of works being undertaken on site and shall allow access to the site for routine visits by the Authority to observe progress in accordance with Condition 97 and specifically to observe remediation works and measures in order to ultimately agree a validation report in accordance with the EMS procedure.



EMS –EMP-04 Audit of Site Works: the contractor will be required to allow the EMS Consultant access to the site for the purposes of conducting site audits in accordance with the EMS procedure.



EMS-EMP-05 Validation of remediation works; the contractor will be required to collect relevant information as required for the preparation of validation reports for submission in accordance with the EMS procedure.



EMS-EMP-06 As Built Records: the contractor will be required to provide asbuilt drawings of all construction works which impact, or may impact on the environment, such as monitoring wells and decommissioning, all services and service corridors and other items including, but not limited to, those listed in the procedure



EMS-EMP-07 Developer Environmental Monitoring: the Competent Authority’s requirements for environmental monitoring will be confirmed in accordance with the EMS procedure.



EMS-ADD-01 Electronic Transfer of Geo-environmental Data; the contractor will be required to submit all ongoing environmental monitoring data, site investigation and remediation data to the EMS Consultant in AGS 3 format and with the accompanying metadata in accordance with the EMS procedure

3.4.2

Relevant codes of practice

A preliminary environmental risk assessment has been prepared for the works to identify where potential environmental impact may occur and where mitigation measures may be required. The environmental risk assessment is presented in Appendix D. The following Codes of Practice have been identified as applicable to the works in general: 

EMS-COP-01: Ground investigation. Additional ground investigation works will be required to characterise areas of PQ Zone A where limited information is available (along the Hotel Approach Road and AEG Service Access Road for example). Ground investigation will be implemented in accordance with


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industry best practice and methods will be employed to prevent cross contamination. 

EMS-COP-02 Remediation Works. The requirement for any specific remediation works will be defined following completion of the ground investigation works and an assessment of the ground conditions in accordance with the remediation strategy for Greenwich Peninsula. Any remediation measures will be compatible with any exiting remediation measures.



EMS-COP-03 Waste Management. The works shall be designed to minimise the generation of waste and seek to recover and re-use as much material as possible.



EMS-COP-04 Dewatering. Any contaminated perched water encountered during the works will need to be suitably disposed of. No waters shall be discharged to the Thames.



EMS-COP-05 General Earthworks. All earthworks will be undertaken in accordance with the Remediation Strategy Framework and the Earthworks and Remediation Scheme Design for Greenwich Peninsula.



EMS-COP-06 Foundations and Underground Structures. The design and installation of any foundations and underground structures shall protect the groundwater environment and mitigate the potential for creating pathways between aquifer units. The design of the retaining wall will need to consider these requirements.



EMS-COP-07 Underground Services and Drainage. The design of the service and drainage routes will include measures to prevent the migration of perched water along service corridors and ensure long term durability to the services through the use and replacement of existing barrier systems.



EMS-COP-10 Soft Landscaping Works. Soft landscaping will be designed to minimise infiltration from rainfall. Where water features are included, these shall include leak prevention measures and consideration given to water quality monitoring.



EMS-COP-11 Control of Soil Gases. Control measures for soil gases and vapours will be designed and constructed with reference to industry best practice and guidelines. All works shall include appropriate personal protective equipment (PPE) for construction workers, and for adequate protection of future services maintenance personnel where appropriate



EMS-COP-12 Boundary Interfaces. All boundary interfaces, ie. between remediation measures or edges or development plots, require appropriate continuity and compatibility to be incorporated into their design and implementation. Where a boundary is identified the EMS Consultant shall review and agree upon the proposed solution prior to agreeing the Works Method Statement (Design).



EMS-COP-13 Environmental Health and Safety. All works shall comply and implement all relevant legislation and guidance relating to environmental health and safety. Best practice working methods used to minimise risk and/or exposure are preferable to the increased use of protective equipment by those involved in the works.



EMS-COP-14: Selection, Supervision and Management of Contractors. Contractors with a proven experience of undertaking similar work in


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potentially contaminated conditions shall be chosen. Contractors shall be adequately supervised and instructed by an Engineer or Environmental Scientist experienced in supervising equivalent works in contaminated land. No works are to proceed or continue without the supervisor being present on site. The management and supervision of waste shall be controlled and documented in accordance with industry requirements and details shall be provided with the Works Method Statement Construction 

EMS-COP-15 Roads and Parking Areas. Consideration for the infiltration of rainfall and the provision of surface water drainage shall be included within the design scope and refer to the existing environmental ground conditions present. Road and Parking area surfacing should be specified as impermeable. All run off should be piped and discharged to the appropriate storm water system.

The details on how the design of the public realm and infrastructure works will comply with the EMS codes of practice will be contained within the WMS(D) for these works.


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4

Environmental monitoring

4.1

Construction monitoring

Monitoring of dust, effluent discharge arising from dewatering operations, ground gases in confined spaces, and testing of spoil leaving the site for disposal will be undertaken during the construction works. Details of specific proposals will be included in the Design and Construction WMSs as required by EMS-EMP-07 Developer Environmental Monitoring

4.2

Groundwater monitoring

The proposed development work is unlikely to extend into the underlying RTD controlled waters aquifer. Therefore no groundwater monitoring is considered necessary during these works and none is proposed. However this approach will be agreed with the Local Authority and Environment Agency prior to the works. None of the wells being sampled by Atkins (for HCA) for the long term groundwater monitoring being undertaken across the Greenwich Peninsula, described in EMS-EMP-08 (English Partnerships Groundwater Monitoring), will be affected by the works. The location of the long term groundwater monitoring wells is presented in Appendix E.


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Figures


Figure 1 Figure 2 Figure 3 Figure 4


Site location plan Current Site Layout Plan Ground investigation locations Remediation excavations and historical ground investigation locations


Arup Method Statement

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