Land at Middlebrook, Bolton - Phase 1 Report · X:\Project Files\2601-2700\2679\Phase 1...

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X:\Project Files\2601-2700\2679\Phase 1 Geo-Environmental Report (Sept 2012)\Land at Middlebrook, Bolton - Phase 1 Report.doc

PHASE 1 GEO-ENVIRONMENTAL GROUND INVESTIGATION

LAND AT MIDDLEBROOK, BOLTON

FOR

BOLTON WANDERERS FOOTBALL CLUB

Integra Consulting Engineers Ref: 2679 Fountain House Rev: - Fountain Street By AE Manchester M2 2EE Tel 0161-237-3400 Fax 0161-237-3635 Date: Sept 2012 Email [email protected]


CONTENTS 1.0 EXECUTIVE SUMMARY 2.0 INTRODUCTION 2.1 General 2.2 Previous Site Investigations 3.0 BRIEF 4.0 LIMITATIONS OF INVESTIGATION WORK AND REPORT 5.0 THIRD PARTIES 6.0 SCOPE OF INVESTIGATION WORK 6.1 Walk Over Survey 6.2 Desk Study Documentation 7.0 FINDINGS 7.1 Description of the Site 7.2 Walk Over Survey 7.3 Geology 7.4 Site History 7.5 Waters and Flooding 7.6 Hazardous Installations, Landfill and Waste 7.7 Mining 7.8 Radon 8.0 CONCLUSIONS 8.1 General 8.2 Geology 8.3 Contaminated Land Legislative Framework 8.4 Sources of Contamination and Probable Contaminants 8.5 Pathways for Contamination 8.6 Targets of Contamination 8.7 Conceptual Model for Human Health Risk Assessment 8.8 Conceptual Model for Waters Risk Assessment 8.9 Preliminary Risk Assessment Summary 8.10 Scope of Intrusive Geotechnical Ground Investigation 9.0 RECOMMENDATIONS


APPENDICES APPENDIX 1 SITE LOCATION PLANS AND AERIAL PHOTOGRAPH APPENDIX 2 WALK OVER SURVEY PHOTOGRAPHS APPENDIX 3 HISTORICAL ORDNANCE SURVEY MAPS APPENDIX 4 ENVIRONMENTAL MAPS APPENDIX 5 LANDMARK ENVIRONMENTAL REPORT APPENDIX 6 EXTRACTS OF BGS GEOLOGICAL MAP AND BOREHOLE LOGS

APPENDIX 7 EXTRACTS OF HPA AND BRE211 RADON ATLAS FOR ENGLAND

AND WALES APPENDIX 8 COAL AUTHORITY MINING REPORT APPENDIX 9 FACTUAL INFORMATION RELATING TO PREVIOUS SITE

INVESTIGATION WORKS APPENDIX 10 PROPOSED DEVELOPMENT PLAN


1.0 EXECUTIVE SUMMARY

1.1 Integra Consulting Engineers Ltd has been instructed by Bolton Wanderers Football

Club to undertake a Phase 1 geo-environmental ground investigation for land at

Middlebrook, Horwich, Bolton.

1.2 It is the Client’s intention for the site to be partially redeveloped to accommodate:

• The construction of 4 No. office / commercial buildings to the north west of

the existing Reebok stadium.

• The construction of a sports hall facility linked to the existing Bolton Arena.

• The construction of a sports stand to the west of the existing floodlit sports

track in the western section of the site.

• The construction of an educational facility in the north western section of the

site to the south of the current Police Station.

• The construction of an office / commercial building abutting the west

elevation of the existing Reebok stadium.

Consequently, the objectives of the report were to assess the probable geological

and contaminated land conditions on and beneath the surface and to identify

potential contaminants present at the site. A preliminary conceptual model was then

to be developed to define the scope and extent of any further investigations

deemed necessary.

1.3 The site is located in an area of sports / recreational development, including Bolton

Wanderers Football Club, in Middlebrook, Horwich, Bolton. The national Ordnance

Survey grid reference for the centre of the site is E 364440, N 409480 and it is

located at post code BL6 6SW. The site is bordered by a railway to the west, open

land, access roads and retail units to the north, retail units and access roads to the

east and access roads and a hotel to the south. The site predominantly consists of

hardstanding covering an irregular shaped area of circa 24 hectares (maximum

dimensions 550m x 600m) and consists of a sports stadium, sports recreational

facilities, car parking and access roads.


1.4 The desk study carried out indicates that the site is underlain by a mixture of soft

clays / silts and loose sands together with peat / organic deposits within the top 3m

below ground level which are in turn underlain by a mixture of soft to firm cohesive

deposits and / or loose to dense granular deposits which are in turn typically

underlain by mudstone at 10m to 13m below current site levels. In order to

determine the ground conditions with a greater degree of certainty following the

variability recorded within the previous site investigation works and allow design of

the proposed building foundations, drainage, services and external areas to be

undertaken, it is recommended that boreholes and trial pits are constructed at the

site. The quantity, depth, specification and location of all the above noted

exploratory holes will naturally be based on the finalised development plan and

proposed building specifications.

1.5 The Coal Authority report ref: 51000141585001 was obtained as the site is within a

recognised coal production area. The report confirms the site is not within the likely

zone of influence from workings on the surface from past underground workings.

Furthermore, the Arley Coal seam located outcropping across the north western

section of the site is not considered to pose a significant risk in relation to previous

mining activities which could have potentially led to ground instability issues at the

development site. However, it is regarded that if sports stand development works

are to be undertaken at the western section of the site, exploratory holes should be

constructed in order to enable this risk to be appropriately assessed.

1.6 After appraising the available historical and contemporary data, the site appears to

have no potentially contaminative sources with the site developed into its present

state from greenfield in the 1990’s. Furthermore, no potential off site contaminative

sources were recorded in proximity to the site.

1.7 Following a review of BRE 211 and HPA / BGS radon reports, no radon protection

measures are deemed necessary at the post development site.


1.8 Utilising the guidance stipulated in CIRIA 665 (2007) and CIRIA 552 (2001), the

probability and consequence of the identified potential ground gas sources,

principally the underlying peat / organic deposits, on the development is considered

to result in a moderate to high risk. Consequently, it is recommended that ground

gas and groundwater monitoring is undertaken across the 5 No. development areas

to allow a Ground Gas Risk Assessment to be undertaken. It is recommended that

ground gas monitoring is undertaken for a minimum period of 3 months with further

ground gas monitoring potentially necessary dependent on the findings from the

initial three month period.

1.9 As a result of the information gathered from this report, there is a low potential risk

to human health and controlled waters at the current and proposed site

development areas principally due to a lack of a contamination sources identified at

the site. Consequently, a Phase 2 environmental intrusive investigation is not

deemed necessary.

1.10 The recommendations of this report are dependent on liaison / agreement with the

Environment Agency and Bolton Council. It should be noted that, if any visual or

olfactory evidence of contamination is encountered during remediation or

construction work, then the Local Authority Environmental Health Officer and

Environment Agency should be contacted immediately in order to agree any

necessary remediation measures.


2.0 INTRODUCTION 2.1 General

This Phase 1 geo-environmental ground investigation and report has been prepared

at the request of Bolton Wanderers Football Club.

Instructions to proceed were received in August 2012. Desk study work was

undertaken between 10 September 2012 and 28 September 2012. The walk over

survey was carried out on 21 September 2012.

This Phase 1 report is to be used for submission to the Local Authority as part of a

planning application as it is the Client’s intention for the site to be partially

redeveloped.

The proposed redevelopment works consist of:








• The construction of an office / commercial building abutting the west

elevation of the existing Reebok stadium.

The proposed development plan is contained in Appendix 10 - it should be noted

that this proposed development plan is provisional at this stage.


2.2 Previous Site Investigations

Two previous site investigation reports that focused on the development of the site

into its present day site use were made available through the Client and have been

reviewed and summarised below.

These reports are:

• The ‘Bolton Sportsworld, Horwich - Factual Report on Ground Investigation’

undertaken by Exploration Associates Ltd following instructions to proceed

from Deakin Callard and Partners, consulting engineers on behalf of Alfred

McAlpine Building (North) in August 1995.

• A ‘Report on Gas Protection Measures’ undertaken by Card Geotechnics

following instructions to proceed from Deakin Callard and Partners,

consulting engineers on behalf of Alfred McAlpine Building (North) in

November 1996.

Factual information relating to the above reports including borehole logs,

exploratory holes, monitoring data and testing are contained in Appendix 9.

Bolton Sportsworld, Horwich - Factual Report on Ground Investigation by

Exploration Associates Ltd

The aim of the report was to provide information on the ground conditions for the

design and construction of the existing site development in 1995.

The ground investigation consisted of:

• 39 No. shell and auger boreholes to depths ranging from 2.85m to 15.50m

below ground level

• 28 No. trial pits to depths ranging from 1.40m to 4.05m below ground level

• 22 No. static cone penetration tests

• Groundwater identification and sampling

• Geotechnical classification and testing including shear strength, index

properties, California bearing ratio (CBR), particle size distribution (PSD),

compressibility and aggressiveness of the soils and groundwater


The Exploration Associates Ltd investigation covered an extensive area including

the re-development site under investigation within this report. Consequently, the

following review and associated comments are focused on the proposed

development plan contained within Appendix 10 particularly covering:








• The construction of an office / commercial building abutting the western

section of the existing Reebok stadium.

The previous site investigation works undertaken in 1995 indicate the following

typical ground conditions beneath the envelope of the 5 No. proposed buildings at

the time of undertaking the site investigation works:

The typical ground conditions beneath the envelope of the proposed 4 No. office /

commercial buildings to the north west of the existing Reebok stadium consisted of:

• Topsoil to a depth of 0.1m underlain by

• Made ground consisting of firm to very stiff, sandy, silty, gravelly clay with

occasional organic debris, granular deposits and brick fragments to depths of

between 0.6m and 0.9m underlain by

• Loose / soft, pale grey, silty sand or sandy silt to a depth of 3.5m underlain

by

• Grey brown, gravelly sand with occasional silt inclusions to a minimum depth

of 4.0m below ground level.


Peat / peat pockets were recorded on numerous occasions:

• In TP14 between 0.9m and 1.25m (0.35m thick) at 106.3m AOD


• In TP7 between 1.85m and 2.9m (1.0m thick) at 106m AOD



• In TP8 in excess of 3.8m at 103m AOD

Groundwater was recorded in the following exploratory holes:

• TP7 at 3.9m (103.9m AOD) and was classified as a seepage


• TP19 at 1.9m (106.7m) and was classified as a seepage

The exploratory holes regarded as relevant to the proposed 4 No. office /

commercial buildings include trial pits TP7, TP8, TP14, CPT14 and CPT15.

These trial holes were excavated from ground levels varying between 106.82m

AOD and 108.52m AOD.

The typical ground conditions beneath the envelope the proposed construction of

sports hall facility linked to the existing Bolton Arena consisted of:


• Made ground consisting of loose / soft, brown, silty, clay or sand with brick

fragments to depths of between 0.5m and 0.8m underlain by

• Very soft / soft, grey, silty clay or clayey silt from a minimum depth of 4.0m to

termination.

Peat / organic clays were recorded on numerous occasions:


• In TP12 between 2.7m and at least 4.0m (in excess of 1.3m thick) at 103.5m

AOD



Furthermore, a tree stump was recorded in TP12 at a depth of 1.6m (104.6m AOD)

below ground level.




The exploratory holes regarded as relevant to the proposed sports hall include trial

pits TP9 and TP12 - these holes were excavated from ground levels of 105.85m

AOD and 106.18m AOD respectively.

The typical ground conditions beneath the envelope the proposed sports stand

consists of:

• Topsoil to a depth of between 0.1m and 0.3m underlain by

• Made ground consisting of clayey, silty sand and silty clay to a depth of 0.7m

underlain by

• Soft to firm, orange/grey, silty, very sandy, gravelly clay between a depth of

1.5m and 1.8m underlain by

• Soft / loose, brown / grey, clayey, slightly sandy silt or very silty, sand to a

depth of between 2.3m and 2.9m underlain by

• Firm to stiff, grey, silty, sandy, slightly gravelly clay with occasional 0.2m

thick sand bands from a depth of approximately 3.0m (104.5m – 107m AOD).

At 4.5m to 6.0m (101m AOD to 102.6m AOD), the clay becomes very stiff

underlain by

• Highly weathered mudstone to a depth of between 10.0m and 11.6m

(97.11m AOD and 98.08m AOD)

No peat or organic material was recorded within these exploratory holes.


• TP25 at 2.4m (107m AOD) and was classified as a seepage

• BH26 at 3.9m (103m AOD) and was classified as a seepage


The exploratory holes regarded as relevant to the proposed sports stand include

boreholes BH25 and BH26 together with trial pit TP25. These holes were excavated

from ground levels varying between 107.11m AOD and 109.68m AOD.

The typical ground conditions beneath the envelope the proposed educational

facility consists of:

• Topsoil to a depth of between 0.1m and 0.2m underlain by

• Very soft / soft, very clayey silt or silty clay with occasional sand bands to a

depth of between 0.6m and 1.5m (105.2m AOD and 105.3m AOD) underlain

by

• Spongy peat to depths of between 3.5m and 3.8m (103.3m AOD and 101.9m

AOD) with a thickness of 2.9m and 2.3m, respectively underlain by

• Very soft, very clayey silt or silty sand with pockets of organic material to a

depth of between 3.8m and 3.9m (103m AOD and 101.9m AOD).

Groundwater seepages were recorded in TP8 and TP13 at depths of 1.2m and

1.5m below ground level.

The exploratory holes regarded as relevant to the proposed education facility are

trial pits TP8 and TP13 which were excavated at ground levels of 106.82m AOD

and 105.78m AOD respectively.


The typical ground conditions beneath the envelope the proposed office /

commercial building abutting the western elevation of the existing Reebok stadium

consists of:

• Firm to stiff, brown / grey, silty, sandy, slightly gravelly clay to a depth of

between 1.8m and 2.45m underlain by

• Soft, grey / brown, sandy, silty, clay or clayey silt to a depth of between

4.45m and 4.90m (104.8m AOD and 105.3m AOD)

• Medium dense, brown, slightly clayey / silty gravel with occasional cobbles

from a depth of approximately 5.0m (103.4m AOD to 104.8m AOD) underlain

by very dense gravel at a depth of 9.0m to 12.0m (100m AOD to 101m AOD)

underlain by

• Weathered siltstone at a depth of between 95m AOD and 95.9m AOD

Peat / peat pockets were recorded on numerous occasions:

• In BH3 between 3.0m and 3.4m (0.40m thick) at 105.9m AOD

• In BH35 between 2.45m and 3.45m (1.0m thick) at 105.5m AOD

• In TP6 in excess of 3.4m at 105.9m AOD

It should be noted that trial pit TP6 recorded made ground consisting of firm to stiff

clay with brick fragments to a depth of 2.2m below ground level.

Groundwater was recorded on numerous occasions across the development area

but, at its shallowest, was identified at approximately 2.0m below ground level.

The exploratory holes regarded as relevant to the proposed office / commercial

development abutting the western elevation of the Reebok stadium include

boreholes BH3, BH4 and BH35 and trial pit TP6 - these holes were excavated /

constructed at ground levels varying between 107.9m AOD and 109.7m AOD.


Card Geotechnics for Deakin Callard and Partners

Card Geotechnics were appointed by Deakin Callard and Partners to undertake an

investigation following the discovery that, during the construction of the pile caps for

the sports stadium, gas had been recorded ‘bubbling up’ through standing water

from the base of certain excavations.

Accordingly, Card Geotechnics installed gas monitoring wells to characterise the

underlying ground gas regime. Subsequent ground gas monitoring recorded

maximum methane concentrations of 64% v/v and maximum carbon dioxide

concentrations of 45% v/v at the site with associated emission rates recorded at low

but variable levels.

Card Geotechnics noted that, over the southern half of the site, the peat became

absent as a distinct layer but was present as pockets within the alluvium which also

contained organic matter.

The source of the methane and carbon dioxide present below the site is noted by

Card Geotechnics to be the underlying peat deposits which is reflected by the

associated consistent concentrations. The variable emission rates were stated by

Card Geotechnics to be a result of the variations in groundwater levels creating

changes in gas driving pressure.

Following a risk assessment, Card Geotechnics state that nominal protection

measures against methane ingress will be required potentially comprising either:

• Below ground floor slab ventilation. Under slab ventilation would need to be

connected to atmosphere, venting stacks or manholes located both inside

and outside the Reebok stadium structure. The under slab venting system

should compromise a 200mm blanket of single size (20mm) aggregate

incorporating gas venting strips connected to atmosphere at either side of

the stadium or


• A gas impermeable membrane incorporated into the floor slab. A ‘Visqueen’

membrane (minimum 0.5mm thick) is already required for the southern part

of the stadium and this could be upgraded to a more robust gas-proof

membrane at minimal extra cost.

Furthermore and consequentially, these measures will be effective in protecting the

structures from the potential ingress of carbon dioxide.

Additionally, removal of the peat from beneath the car park to the north of the

Reebok stadium will remove part of the gas producing source which could

potentially migrate beneath the stadium.


3.0 BRIEF

The brief was to carry out a Phase 1 geo-environmental ground investigation for

land at Middlebrook, Bolton. The extent of the site is shown on the aerial

photograph and site plans contained in Appendix 1. The investigation was to

include for the following studies:

a) A desk study involving examination of available geological maps, BGS

borehole logs, historical Ordnance Survey maps, environmental maps,

previous site investigation work (when available) and accessible historical

records to assess the probable geological and contaminated land conditions

on and below the site.

b) A walk over study of the site to ascertain any evidence of previous and

current site uses that may have caused contamination of the ground and

surface waters at the site. During the walk over survey, the topography of the

site was to be noted along with any land features that could give an

indication of probable sub-surface features and formations.

c) Identify probable contaminants that may be present at the site using current

contaminated land guidance and identify potential receptors which could be

at risk from potential contaminants.

d) Develop a conceptual model for the site to assess the potential risks of

contamination and to undertake a preliminary risk assessment.

e) Determine whether further investigation and assessment is required.

f) Define the scope and extent of further investigations.

A detailed report was to be provided to summarise findings and recommendations.


4.0 LIMITATIONS OF INVESTIGATION WORK AND REPORT

Desk Study References

The desk study has been produced using historical Ordnance Survey maps and

environmental maps available at the time the report has been produced. The

environmental information used was the current information available at the time of

writing but there is no absolute guarantee of accuracy.

Historical Ordnance Survey maps do no provide a comprehensive description of a

site’s history. They provide details of the site from a date prior to the publication of

the map (i.e. a snapshot in time). The period between map editions can be

substantial (i.e. several decades). Not all map series are available for every date

range in many areas of the UK and therefore there will be gaps in this mapped

record for some sites. Potentially contaminative land uses could have been present

and removed during such periods and may therefore not form a part of this

particular record. In addition, there will be potentially contaminative land uses which

are not identified on the map records such as small scale storage / use of

hazardous materials, illegal / unlicensed waste disposal activities etc.

Different map series identify different features utilising different symbols which can

result in features that remain on site being removed from maps. Some features are

also not mapped for security reasons i.e. airfields and other military installations.

These areas are mostly shown as blank areas on historical maps.

Exploratory Holes

Where the spacing of exploratory holes for future intrusive investigation work has

been presented as part of this report, the spacing has been determined to provide a

reasonable indication of the general ground conditions and extent of land /

groundwater contamination on the site but the number has ultimately been limited

by commercial constraints. The ground conditions at the proposed exploratory holes

are no absolute guarantee of the ground conditions between such locations. Due

allowance should be made for the possibility of variation in conditions between

exploratory hole locations when preparing any assessments of the final foundation

and land / groundwater remediation proposals.


Extent of Contamination Studies

This report is strictly limited to the nature of contamination contained within the

ground and groundwater at the site. The report does not cover environmental

aspects such as air or noise pollution and ground vibrations and the like. In

addition, ecological matters relating to wildlife, flora and fauna have not been

investigated as part of this report. In particular, the site has not been inspected for

the presence or otherwise of Japanese Knotweed. It is recommended that the

Client appoints a specialist in this subject to carry out a detailed inspection of the

site if its presence is suspected.

Flooding

Flooding in this report is defined as flooding caused by the sea, ditches, rivers,

streams, ponds, lakes, reservoirs and the like. It does not extend to flooding

caused by surcharged piped drainage systems and investigations into flooding of

this nature are excluded from this report.


5.0 THIRD PARTIES

This report has been prepared for the sole use of Bolton Wanderers Football Club.

It must not be copied or passed onto any third party or used for any purpose other

than which it was prepared without the permission of the author. This report is

copyright.


6.0 SCOPE OF INVESTIGATION WORK

6.1 Walk Over Survey

The site was visited during wet and overcast conditions and the objectives of the

site walkover were, where applicable:

• to identify and assess visual and olfactory evidence of contamination e.g.

staining of concrete / soils, odours, presence of gas protection measures etc;

• to identify locations of potential sources of contamination and assess their

conditions i.e. tank location, presence / condition of secondary containment /

bunds, location of fill points, process areas;

• to identify surrounding land uses and any potentially contaminating activities;

• to identify / verify the presence of potential receptors (on site and off site)

which may be affected by identified sources;

• to obtain information on activities / procedures and standards of

housekeeping etc.

• to assess site access and potential investigation locations and constraints.

• to assess any visual subsurface geotechnical features / anomalies e.g.

foundations, made ground, subsidence etc

Photographs were taken of the site during the walkover survey and these

photographs are contained in Appendix 2.

6.2 Desk Study Documentation

The following documents were obtained and examined during the desk study:

a) An aerial photograph of the site dated 2000. The photograph is contained in

Appendix 1.


b) Historical Ordnance Survey maps as follows:

• 1:2500 dated 1863

• 1:10560 dated 1868

• 1:2500 dated 1901

• 1:10560 dated 1901

• 1:2500 dated 1926

• 1:10560 dated 1927

• 1:2500 dated 1938

• 1:10560 dated 1938 – 1952

• 1:10560 dated 1951

• 1:10000 dated 1957

• 1:2500 dated 1967 – 1968

• 1:10000 dated 1970 – 1976

• 1:2500 dated 1973

• 1:10000 dated 1975

• 1:2500 dated 1987 – 1990

• 1:10000 dated 1988

• 1:10000 dated 1992

• 1:1250 / 2500 dated 1993

• 1:10000 dated 2000

• 1:10000 dated 2006

• 1:10000 dated 2011

These maps are contained in Appendix 3.

c) Environmental maps obtained through Envirocheck as follows:

• Environment Agency and hydrological map dated 1999 - 2012

• Groundwater vulnerability map dated 1999

• Sensitive land uses map dated 1997 - 2012

• Summary maps showing locations of recorded waste sites, industrial

land use sites and hazardous substances sites in adjacent areas.

These maps are contained in Appendix 4.


d) An environmental report obtained from Landmark, the environmental

database company, which provides a list of recorded past and present

activities at or adjacent to the site which could have an impact on the levels

of contamination in the soils and groundwater at the site. This report is

contained in Appendix 5.

e) The British Geological Survey (BGS) 1:10,560 solid and drift map (reference

Lancashire 86 SW). A part extract of the map covering the area under

consideration is contained in Appendix 6. Seven BGS boreholes were

obtained in close proximity to the proposed buildings including:

• SD60NW 232 and 251 located within close proximity to the proposed

office / commercial buildings to north west of the existing Reebok

stadium

• SD60NW 296 and 322 located beneath the envelope of the proposed

construction of a sports hall facility linked to the existing Bolton Arena

• SD60NW 299 and 300 located beneath the envelope of the proposed

sports stand in the western section of the site

• SD60NW 242 located beneath the envelope of the proposed

educational facility in the north western section of the site

No relevant BGS borehole information was available for the proposed office /

commercial building abutting the western section of the existing Reebok

stadium. The extracts noted above have been copied under licence from the

British Geological Society.

f) The Indicative Atlas of Radon for England and Wales published by the British

Geological Survey and the Health Protection Agency was examined to

assess the probable presence or otherwise of radon gas in the ground.

Extracts of the relevant maps are contained in Appendix 7.

g) Factual information relating to the site investigation works undertaken by

Exploration Associates Ltd and Card Geotechnics, as detailed in section 2.2,

are contained within Appendix 9.

h) Coal Authority Mining report reference 51000141585001. This report is

contained in Appendix 8.


7.0 FINDINGS

7.1 Description of the Site

The site is located in an area of sports / recreational development, including Bolton

Wanderers Football Club, in Middlebrook, Horwich, Bolton. The location is shown

on the site location plans in Appendix 1. The national Ordnance Survey grid

reference for the centre of the site is E 364440, N 409480 and it is located at post

code BL6 6SW. The site is bordered by a railway to the west, open land, access

roads and retail units to the north, retail units and access roads to the east and

access roads and a hotel to the south.

An aerial photograph of the site prior to works commencing is also contained in

Appendix 1.

The site predominantly consists of hardstanding covering an irregular shaped area

of circa 24 hectares (maximum dimensions 550m x 600m) and consists of a sports

stadium, sports recreational facilities, car parking and access roads.

As discussed in section 2.1, only localised areas of the overall site are to be

redeveloped and consequently this report focuses primarily on these 5 No. areas as

opposed to the site as a whole.


7.2 Walk Over Survey

During the walk over survey, the following features were noted relating to geology

and contaminated land matters with respect to the 5 No. areas at the site identified

for redevelopment.

Geology

At each of the 5 No. development areas the existing site uses were inspected:

• The envelopes of the proposed 4 No. office / commercial buildings to the

north west of sports stadium are being utilised as a car park

• The envelope of the proposed sports hall facility linked to the existing Bolton

Arena is being utilised as an Astroturf sports pitch, car parking, access

pathway and an area of soft landscaping

• The envelope of the proposed sports stand to the west of the existing floodlit

sports track is being utilised a running track and soft landscaping

• The envelope of the proposed educational facility in the north western site

section had no site use and is overlain by dense gravel materials

• The envelope of the proposed office / commercial buildings abutting the

western section of the existing Reebok stadium is overlain by hardstanding

materials utilised for accessing the stadium

The majority of the site development areas are topographically flat with only a slight

gradient across the current car parking area identified for the proposed office /

commercial development to the north of the Reebok stadium.

Due to the developed / hardstanding nature of the site, no information relating to the

underlying geology was observed although areas of standing water were noted

across the site.

Numerous overhead and underground services were noted across the site.

Contaminated Land

No potential contaminative sources were identified at the site.

Photographs taken during the walkover survey are contained in Appendix 2.


7.3 Geology

The BGS 1:10,500 geological map of the area shows the site to be underlain by

glacial till (boulder clay) in the eastern and western site sections and alluvium

deposits across the central site section. These superficial deposits are underlain by

shale deposits of the Lower Coal Measures.

It should be noted that the Arley Mine (coal seam) is conjectured to outcrop,

trending from south east to north west across the extreme north western section of

the site, dipping towards the south west. This outcrop is postulated to lie in close

proximity to the proposed sports stand.

An extract of the geological map is contained in Appendix 6.

7.3.1 BGS Borehole Logs

As detailed in section 6.2, 7 No. BGS borehole logs were obtained which are

located within the envelope or in close proximity to the 5 No. areas identified for

redevelopment. Consequently, each of the proposed redevelopment areas will be

appraised separately.

Proposed 4 No. Offices / Commercial Development

Two BGS borehole logs, SD299NW 251 and 323 are located approximately 50m

from the proposed development envelope.

The SD299NW 251 borehole is located to the east of the proposed development

and was undertaken in September 1979, based at 113.36m AOD.

The second borehole, SD299NW 323, was located approximately 50m to the north

of the proposed development and was undertaken in February 1987m AOD, based

at 106.3m AOD.

The two BGS boreholes recorded significantly variable ground conditions and were

constructed at significantly different AOD levels as noted above.


Ground conditions recorded immediately to the north of the site (SD299NW 323)

consisted of:

• Topsoil to a depth of 0.2m (106.1m AOD) underlain by

• Yellow / brown, sandy clay to a depth of 0.6m (105.7m AOD) underlain by

• Soft, brown peat to a depth of 3.8m (102.5m AOD) underlain by

• Dense, grey / brown, slightly silty, sandy gravel with cobbles to a depth of

10.2m (96.1.0m AOD) with occasional firm clay bands underlain by

• Grey, weathered mudstone.

Groundwater was noted to rise from 3.8m (102.5m AOD) to a depth of 0.8m

(105.5m AOD) after 20 minutes.

Conversely, the borehole to the east of the proposed development (SD299NW 251)

was undertaken from level approximately 7m higher and recorded significantly

different ground conditions consisting of:

• Topsoil to a depth of 0.3m (113m AOD) underlain by

• Firm, brown, silty sandy, gravelly clay to a depth of 1.8m (111.5m AOD)

underlain by

• Medium dense, brown sand and gravel to a depth of 7.4m (106m AOD)

underlain by

• Firm to stiff, grey, very silty clay to a depth of at least 10.0m (103.3m AOD).

Groundwater was noted to rise from 7.0m (106.4m AOD) and 9.5m (103.8m AOD)

to a depth of 5.3m (108m AOD).

Proposed sports hall facility linked to the existing Bolton Arena

Borehole logs SD60NW 299 and 322 are located in the south western section of the

envelope of the proposed sports hall facility linked to the existing Bolton Arena.

Furthermore, SD60NW 296 was undertaken in December 1980 at 106.4m AOD in

the extreme south western corner of the proposed development envelope.

Borehole SD60NW 322 was undertaken in February 1987 at 105.82m AOD and

was located in the central section of the site approximately 30m north east of the

borehole SD60NW 296..


BGS boreholes SD60NW 299 and 322 recorded significantly different ground

conditions from those recorded in the extreme south western corner (SD60NW

296). Ground conditions in the extreme south west corner consisted of:


• Soft to stiff, sandy, gravelly clay with gravel bands to a depth of 6.1m

(100.3m AOD) underlain by

• Medium dense, slightly clayey sand and gravel to a depth of 7.2m (99.2m

AOD) underlain by

• Weathered, brown clayey mudstone.

Groundwater was noted to rise from 2.8m (103.6m AOD) to a standing depth of

1.7m (104.7m AOD).

Conversely, the borehole further to the north east (SD60NW 322) undertaken

approximately 0.6m lower in elevation and seven years later than the previous

borehole recorded vastly different ground conditions, namely:


• Brown and grey, silty, sandy clay to a depth of 1.4m (104.4m AOD) underlain

by

• Brown peat to a depth of 3.8m (102m AOD) underlain by

• Loose, grey clayey, silty becoming gravelly at greater depth sand to a depth

of 11.6m (94.2m AOD) underlain by

• Highly weathered, weak mudstone.

Groundwater was noted to rise from 3.8m (102m AOD) to a depth of 0.76m (105m

AOD) after 20 minutes.

Proposed Sports Stand

Two BGS borehole logs, SD60NW 299 and 300 are located in the envelope of the

proposed sports stand. Both boreholes were undertaken utilising cable percussive

methods in December 1980 and at similar elevations, namely 109.6m AOD and

109.9m AOD, respectively.


Both boreholes recorded similar underlying ground conditions, namely:


• Soft to firm sandy clay to a maximum depth of 2.4m (107.5m AOD) underlain

by

• Firm to stiff, brown sandy, gravelly clay to a depth of at least 6.0m (103.6m

AOD).

Groundwater was recorded at 2.5m (107.1m AOD) and 4.3m (105.6m AOD) and

rose to a depth of between 2.2m and 2.9m.

Proposed Educational Facility

A single BGS borehole, SD60NW 242 was recorded beneath the envelope of the

proposed educational facility. The borehole was undertaken utilising cable

percussive methods in September 1979 and was based at 105.543m AOD. The

ground conditions recorded were:


• Soft, brown peat to a depth of 5.0m (100.54m AOD) underlain by

• Soft, grey, silty, sandy clay to a depth of 5.8m (99.7m AOD) underlain by

• Loose, grey, silty, sand with gravel bands to a depth of 7.5m (98m AOD)

underlain by

• Firm, grey, silty, sandy, gravelly clay to a depth 8.5m (98m AOD) underlain

by

• Sandstone.

Groundwater was struck at a depth of 8.5m (97m AOD) and rose to a standing

depth of 0.5m (105m AOD).

No BGS borehole information was available for the proposed office / commercial

building abutting the western section of the current sports stadium.


7.4 Site History

The site development history has been researched with reference to historical maps

and street plans. These are included in Appendix 3 to this report and the principal

observations, divided into site and off site history are summarised below.

Site History

Off Site History

The majority of the off site history consisted of rural land with nominal site uses,

with the exception of these pertinent land uses:

• Red Moss (large peat deposits) and later refuse tip from <1850 located

approximately 100m north of site boundary.

• Mineshaft (Barton Fold Colliery) and associated chimney disused by early

twentieth century located approximately 200m west of site

• Numerous infilled surface water features and quarries within 250m of site

boundaries.

It should be noted that the 5 No. areas identified for development are located in

excess of 250m of the above off site land uses.

Dates Site Features

<1849 – 1990s

The site consisted of rural land including field boundaries, land drains, trees and surface water courses (Middle Brook). Middle Brook was noted to flow from north to south through the central and western site sections. In the northern site section, the surface water feature is met by a second surface water course flowing from east to west. Only nominal changes to the site are recorded during this period including construction of bridges and modifications to field boundaries.

1990s - 2012

The site was developed into its present day site use which includes a sports stadium and associated sports facilities, access roads and car parking.


7.5 Waters and Flooding

Environmental data relevant to the site and its immediately surrounding area has

been obtained from sources available in the public domain. In addition, an

environmental report was obtained from Landmark, the commercial suppliers of

environmental data. The Landmark report and associated maps that have been

inspected are presented in Appendices 4 and 5 and the principal observations in

relation to waters and flooding can be summarised as follows:

Flooding

• The majority of the site is located within an area designated as Flood Zone 1,

2 and 3

Surface Water

• The nearest surface water feature, Middle Brook is located on site and is

classified as GQA Grade River Quality B

• There are no surface water abstraction points within 1km of the site

Hydrogeology

• The site is underlain by bedrock which is classified as a low permeability

Secondary A (major) aquifer of low leaching potential

• The superficial deposits located across the central section of the site is

classified as a Secondary A (minor aquifer) with the remaining site area

overlain by unproductive low permeability glacial till

• The site is not located within 1km of a Source Protection Zone

• There are 6 No. groundwater abstraction points within 1km of the site with

the nearest located approximately 588m north of the site. These abstraction

points are associated with industrial process water, general cooling and

spray irrigation

Pollution Incidents to Controlled Waters

• No recent significant pollution incidents have occurred to controlled waters

within 250m of the site


7.6 Hazardous Installations, Landfill and Waste

The following information relating to hazardous installations, landfill and waste

obtained from the Landmark report, published information and the walkover survey

can be summarised as follows:

• There are 2 No. Local Authority Pollution Prevention and Controls (LAPPC)

located within 500m of the site namely:

o A Petrol Filling Station (ref: PG1/14) associated with the food retail

unit approximately 30m to the north of the site

o The coating of metal and plastic (ref: PG6/23) associated with Watson

Steel Ltd located approximately 370m south east of the site

• There are 2 No. recorded historic landfills and / or registered contemporary

landfills within 250m of the site namely:

o Red Moss located approximately 50m north west of the site, dated

from 1900 to 1994 and accepted inert, industrial, commercial,

household, special and liquid sludge types of waste.

o Barton Fold Farm located approximately 230m south of the site, dated

1980 to 1990 and accepted between 75,000 and 250,000 tones per

year of inert, industrial, commercial, household and special types of

wastes including asbestos, construction and demolition wastes.

• There are no contemporary potentially contaminative industrial land uses

within 250m of the site

• BGS Estimated Soil Chemistry indicated the following concentrations for the

selected determinands across the site envelope:

o Arsenic 15 - 25mg/kg

o Cadmium <1.8mg/kg

o Chromium 60 - 90 mg/kg

o Lead <150mg/kg

o Nickel <15 - 30mg/kg


7.7 Mining

7.7.1 Coal / Fireclay Mining

The Coal Authority report ref 51000141585001 was obtained as the site is within a



This information is consistent with the findings of the geological map desk study.

No other issues were raised relating to present or future working (other than the

usual reserved rights for extraction of remaining coal) or undocumented historical

shallow mine workings.

As discussed in section 7.3., the Arley Mine (coal seam) is conjectured to outcrop in

close proximity to the proposed sports stand in the western section of the site.

Barton Fold Colliery, located approximately 150m south west of the site, indicates

that the Arley Mine is proven at 129 feet and 4 inches (approximately 38m) below

ground level (approximately 30m below bedrock level).

The Arley Mine is known to between 0.9m and 1.2m in thickness.

7.7.2 Brine Extraction

The site lies outside a recognised salt / brine extraction area.

7.8 Radon

The Indicative Atlas of Radon in England and Wales produced by the Health

Protection Agency and British Geological Survey indicates that the site lies in an

area where less than 1% of homes are above the action level.

BRE211 ‘Guidance on Protective Measures for New Buildings’ indicates the site to

be in an area where radon protection is not required.

Map 13 of the Indicative Atlas of Radon in England and Wales and Map 13 of BRE

211 ‘Guidance on Protective Measures for New Buildings’ contain information on

the region in which the site is located and are presented in Appendix 7.


8.0 CONCLUSIONS

8.1 General

As a result of undertaking a walkover survey of the site and reviewing the

documented historical activities including previous site investigation works, it is

concluded that the site is at low risk of land contamination, moderate to high risk of

potential ground gas issues and moderate to high risk of potential geotechnical

discontinuities resulting from previous site uses and underlying ground conditions

that could affect the 5 No. proposed development areas.

Proposed Development

As stated in section 2.1 of this report, it is the Client’s intention that the site is locally

re-developed covering:








• The construction of an office / commercial building abutting the western

section of the existing Reebok stadium.

It should be noted that these development proposals are provisional and will require

confirmation at a later date.

The proposed development plan is contained in Appendix 10.


8.2 Geology

The desk study carried out indicates that the site is underlain by a mixture of soft

shallow clays / silts and loose sands together with peat / organic deposits within the

top 3m of the site, underlain by a mixture of soft to firm cohesive deposits and / or

loose to dense granular deposits which are in turn underlain typically by mudstone

at 10m to 13m below current site levels.

The current site levels across the envelope of the 5 No. development areas are

approximately:

• Proposed 4 No. office / commercial development – between 108m AOD and

108.3m AOD

• Proposed construction of sports hall facility linked to the existing Bolton

Arena – 106.5m AOD

• Proposed sports stand – 107.3m AOD

• Proposed educational facility – 105.8m AOD

• Proposed office / commercial building abutting the western section of the

existing Reebok stadium – 109.7m AOD

Based on the current site levels and utilising the previous site investigation works,

the BGS geological map and the BGS borehole logs, it is anticipated that the

ground conditions beneath each of the 5 No. proposed developments will consist of:

• Proposed 4 No. office / commercial development:

o Highly compressible or variable natured deposits including topsoil,

made ground and loose / soft granular or cohesive deposits including

peat deposits were recorded to a depth of typically 5.5m below current

site ground level underlain by

o Suspected medium dense to dense sand and gravel deposits to a

depth of approximately 10m below current site ground level which is in

turn underlain by bedrock (weathered mudstone).

o Groundwater was recorded at a typical depth of between 2m and 6m

below current site ground level.


As noted in section 2.2, Card Geotechnics state that all peat deposits

below the northern stadium car park should be excavated. Removal of

these peat deposits will ideally require confirmation prior to undertaking

any site investigation works.

• Proposed construction of sports hall facility linked to the existing Bolton

Arena:


loose / soft granular or cohesive deposits including peat deposits to a

depth in excess of 11m below current site ground level underlain by

bedrock (weathered mudstone).

o Groundwater was recorded within 1m of the current site ground level

Please note that the secondary information reviewed recorded variable

conditions with stiff clay recorded beneath the envelope of the proposed

development in a single BGS borehole.

• Proposed sports stand development:


made ground and soft cohesive deposits were recorded to a depth of

typically 2m below current site ground level underlain by

o Firm, grey, silty, sandy, slightly gravelly clay to a depth of

approximately 5m below current site ground level where it becomes

very stiff underlain by bedrock (highly weathered mudstone) at a

depth of approximately 10m below current site ground level.

• Proposed Educational Facility development:


loose / soft granular or cohesive deposits including peat deposits to a

depth in excess of 7m below current site ground level underlain by

o Firm, grey, silty, sandy clay to a depth of approximately 9m below

current site ground level underlain by bedrock (sandstone).


• Proposed office / commercial building abutting the western section of the

existing Reebok stadium

o Highly compressible or variable natured cohesive including peat

deposits to a depth of 5.5m below current site levels underlain by

o Medium dense, brown, slightly clayey / silty gravel, becoming very

dense at a depth of 9m below current site level extending to a depth of

12m below current site level underlain by

o Weathered siltstone

However, it should be noted that as a result of the underlying foundations

associated with the existing Reebok stadium, these ground conditions may

not be representative.

Conclusion

In order to determine the ground conditions with a greater degree of certainty

following the variability recorded within the previous site investigation works and

allow design of the proposed building foundations, drainage, services and external

areas to be undertaken, it is recommended that boreholes and trial pits are

constructed at the site.

Furthermore, the Arley Coal seam located across the north western site section is

not regarded as posing a significant risk in relation to previous mining activities

which could potentially have led to ground instability issues at the proposed

development. However, it is regarded that if sports stand development works are to

be undertaken across this section of the site, exploratory holes should be

constructed in order to enable this risk to be appropriately assessed.

The quantity, depth, specification and location of all the above noted exploratory

holes will be naturally be finalised following receipt of the finalised proposed

development plan and proposed building specifications.


8.3 Contaminated Land Legislative Framework

The assessment of contaminated soils is carried out within the current legal

framework, which is based upon the Environmental Protection Act Part 2A and

current national planning guidelines. Under this framework, the potential

contamination of a proposed development site is a material planning consideration.

In addition, land that is deemed harmful to human health or has the potential to

pollute waters can be designated as contaminated land and appropriate

remediation can be enforced by the Local Authority.

Following the “Way Forward” report undertaken by Department for Environment,

Food and Rural Affairs (DEFRA) a new approach to land contamination was issued

by DEFRA and the Environment Agency (EA). Two documents have been produced

which supersede the previous Contaminated Land Reports (CLR) 7 – 10. The two

reports are ‘Human health toxicological assessment of contaminants in soil’

(formerly CLR 9) and ‘Updated technical background to the CLEA model’ (formerly

CLR 10) and other supporting documentation including revised toxicological reports.

Broadly, the approach consists of preparation of conceptual models to illustrate how

potential contamination (source) can reach (through a pathway) humans or

receptors (targets).

As a result of these conceptual models, each of which are site specific, a risk

analysis can be carried out to determine the frequency of testing to establish levels

of source contamination, possible mobility of those contaminants and the potential

hazards those mobilised contaminants could cause to human receptors.

In addition to direct human receptors, water courses, aquifers and agricultural

resources must be considered as these are potential indirect pathways to humans.

The government is part way through the publication of a number of updated

toxicological reports and associated updated Soil Guideline Values which give

guidance on acceptable soil contamination for a limited number of contaminants

and further authoritative guidance on the toxicity of other contaminants for risk

assessment purposes.


As of March 2009, updated toxicological reports and revised Soil Guideline Values

have been published for the following determinands:

• Arsenic

• Nickel

• Selenium

• Benzene

• Toluene

• Ethylbenzene

• Mercury (elemental, methyl and inorganic)

• Xylene (O, M and P)

• Cadmium

• Phenol

• Dioxins, furans etc.

Where no updated toxicological reports or Soil Guideline Values are available, the

existing toxicological reports and associated Soil Guideline Values will naturally be

used to classify the risk and toxicity posed by the selected determinands.

In addition, where updated Soil Guideline Values and/or toxicological reports are

not available, guidance is available from the Environment Agency on acceptable

methods of assessing human health risks utilising recognised methodology

developed in the UK and abroad. The means available to assess human health

risks and to be utilised on this site are as follows:


Assessment

Means

Production of conceptual models Human health toxicological assessment of contaminants in soil and Contaminated Land Report 11

Scope of contamination testing Human health toxicological assessment of contaminants in soil (2009) and DEFRA Industry Profiles

Contamination sampling rates Contaminated Land Report 4 Laboratory testing MCERTS Accreditation Acceptable contamination levels for Arsenic, Nickel, Mercury, Selenium, Ethylbenzene, Toluene, Benzene, Cadmium, Phenol and Xylenes

Updated Published Soil Guideline Value Reports (March 2009 onwards)

Acceptable contamination levels for Chromium and Lead.

Current Published Soil Guideline Value Reports (2002 – 2004)

Acceptable levels for other contaminants except cyanide and except where the conceptual model includes dermal absorption

LQM CIEH (2nd

Edition 2009) / CL:AIRE (GAC January 2010)

Acceptable contamination levels for cyanide and where the conceptual model includes dermal absorption

Updated technical background to the CLEA model

Assessment of Total Petroleum Hydrocarbons within the above framework as adopted by the Environment Agency

Total Petroleum Hydrocarbon Criteria Working Group and updated technical background to the CLEA model

Acceptable contamination levels for selected aqueous determinands

Environmental Quality Standards (EQS) , UK Drinking Water Standards (UK DWS) and River Basin Management Plan Standards

8.4 Sources of Contamination and Probable Contaminants

Evidence obtained from the historical Ordnance Survey maps, the Envirocheck

report with associated BGS estimated geological concentration data, previous site

investigation works and an appraisal of the current site use indicates that no

identified significant source of contamination in relation to the 5 No. areas of

proposed development was recorded.

Consequently, no environmental chemical testing is deemed necessary on the

basis of appraisal of risk to human health and / or controlled waters.

8.5 Pathways for Contamination

Waters

Due to the shallow nature of the underlying perched water and the variable granular

and cohesive nature of the underlying superficial deposits, it is regarded that lateral

and vertical contaminative pathways are present with respect to the surface water

receptor (Middle Brook) and the underlying Secondary A aquifers associated with

superficial and solid geology.


Site Occupants

The pathways along which contamination could potentially reach the targets on site

during use and after completion of development works are detailed in ‘Updated

Technical Background to the CLEA Model’ (Environment Agency 2009) and can be

summarised as follows:

a) Ingestion of soil directly and indoor dust *

b) Inhalation of soil dust (indoor and outdoor)

c) Dermal contact with soil (indoor and outdoor)

d) Inhalation of soil vapours (indoor and outdoor)

e) Oral background

f) Inhalation background

* Treated as one pathway

8.6 Targets of Contamination

Targets for these pathways include the following:

a) Site occupants

b) Construction workers

c) The general public

d) Groundwater contained within Secondary A Aquifer (Westphalian Pennine

Lower Coal Measures Formation).

e) Surface water features (nearby surface water land drain)

f) Subsurface plastic e.g. potable plastic water pipe

g) Building fabric e.g. concrete foundations etc


8.7 Conceptual Model for Human Health Risk Assessment

On the basis that no potential contaminative sources were identified on the site, it is

deemed that the site (5 No. development site areas) does not pose a significant risk

to current or proposed site human health receptors. Consequently, no chemical

testing of the site material is proposed to be undertaken.

8.7.1 Conceptual Model for Ground Gas Risk Assessment

As discussed in section 2.2, the ground gas investigation undertaken by Card

Geotechnics recorded maximum methane concentrations of 64% v/v and maximum

carbon dioxide concentrations of 45% v/v across the site (generated at very low

rates) by the underlying peat deposits.

Further potential ground gas sources have been identified at the site, namely:

• Underlying alluvium deposits

• Underlying shallow made ground deposits (unknown constituents and

quantity)

• Off site organic natural strata and refuse material deposits approximately

100m north of the site associated with Red Moss

• Infilled surface water features and former quarries within 250m of the site

However, due to the prevalence of the peat deposits beneath the site and the

associated significant concentrations recorded as part of the previous ground gas

monitoring work, the other identified ground gas sources are not regarded as

significant to the proposed 5 No. development areas.

Utilising the guidance stipulated in CIRIA 665 (2007) and CIRIA 552 (2001), the

probability and consequence of the identified potential ground gas sources at the

development is considered to result in a moderate to high level of risk.

If any previously unrecorded potential ground gas sources are recorded during the

site investigation works, for instance infilled ground of potentially ground gas

producing materials, then further appropriate ground gas monitoring will naturally be

undertaken.


Source Pollutant Pathways Receptors Risk

Underlying peat / organic deposits

Methane /

Carbon dioxide / Hydrogen Sulphide

High

Alluvium deposits

Carbon dioxide Very low

Shallow made ground deposits

Methane /

Carbon dioxide

Very Low

Off site infilled ground Methane /

Carbon dioxide

Very low

Off site peat and refuse material

Methane /

Carbon dioxide / Hydrogen Sulphide

Ingress and accumulation

Migration, ingress and accumulation

Inhalation of

vapours

Human occupant

Building and Structures

Site Workers

Low

It is recommended that ground gas and groundwater monitoring is undertaken

across the 5 No. development areas to allow a Ground Gas Risk Assessment to be

undertaken. It is recommended that ground gas monitoring is undertaken for a

minimum of 3 months, with further ground gas monitoring undertaken dependent on

the previous findings.

8.8 Conceptual Model For Waters Risk Assessment

On the basis that no potential contaminative sources were identified on the site, it is

deemed that the site (5 No. development site areas only) does not pose a

significant risk to current or proposed site controlled waters receptors.

Consequently, no chemical testing of the site material will be undertaken.


8.9 Preliminary Risk Assessment Summary

Human Health

There is a low potential risk to human health due to the lack of previous site uses /

lack of contaminative source and the anticipated relatively chemically inert nature of

the site materials.

However, it is anticipated that the ground gas poses a moderate to high risk to the

proposed developments.

Waters / Groundwater

There is a low potential risk to controlled waters due to the lack of previous site use

/ lack of contaminative source. If significant contamination concentrations are

recorded then the risk to potential controlled waters will be substantially increased

due to the highly sensitive receptors and anticipated pathways.

8.10 Scope of Phase 2 Intrusive Geo-Environmental Ground Investigation

On the basis that no potential historical or contaminative sources were identified at

the site, it is deemed that the site does not pose a risk to current or proposed site

human health or controlled waters receptors. Consequently environmental testing

will not be required as part of any intrusive investigation.

However, the installation of boreholes and trial pits across the site should be

conducted to allow appropriate tests to be undertaken to allow sufficient

geotechnical data to be collected in order to inform foundation, ground floor slab

and external works design.

Finally, ground gas and groundwater monitoring should be undertaken across the 5

No. development areas to allow appropriate assessment and potential design of

ground gas protection measures or dewatering measures to be undertaken.

The quantity, depth, specification and location of these exploratory holes will be

finalised following receipt of the finalised proposed development plan and proposed

building specifications.


9.0 RECOMMENDATIONS

9.1 As a result of the information gathered from this report, there is considered to be a

low potential risk to human and controlled waters at the current and proposed site,

principally due to the lack of a contamination sources identified at the site.

9.2 Due to geotechnical requirements, site investigation works should be undertaken

across the entire site envelope including sufficient boreholes, trial pits and

associated geotechnical laboratory tests in order to establish the actual ground

conditions with a greater degree of certainty following the variability recorded within

the previous site investigation works at the site in order that designs for foundations

/ roads and underground drainage can be undertaken. The quantity, depth,

specification and location of these exploratory holes will be finalised following

receipt of the finalised proposed development plan and proposed building

specifications.

9.3 Utilising the guidance stipulated in CIRIA 665 (2007) and CIRIA 552 (2001), the

probability and consequence of the identified potential ground gas sources,

principally the underlying peat / organic deposits, on the development is considered

to result in a moderate to high risk. Consequently, it is recommended that ground

gas and groundwater monitoring is undertaken across the 5 No. development areas

to allow a Ground Gas Risk Assessment to be undertaken. It is recommended that

ground gas monitoring is undertaken for a minimum of 3 months, with further

ground gas monitoring undertaken dependent on the initial three month period

findings.

9.4 From the results of the geotechnical intrusive works, the type of foundation

constructions and associated capacities can be calculated and the type of highway

and drainage constructions can be established.

9.5 The recommendations of this report are dependent on the liaison / agreement with

the Environment Agency and Bolton Council. It should be noted that, if any visual or

olfactory evidence of contamination is encountered during remediation or

construction work, then the Local Authority Environmental Health Officer and

Environment Agency should be contacted immediately in order to agree any

necessary remediation measures.


9.6 The Coal Authority report ref 51000141585001 was obtained as the site is within a



Furthermore, the Arley Coal seam located outcropping across the north western site

section is not regarded as posing a significant risk in relation to previous mining

activities which could potentially have led to ground instability issues at the

proposed development. However, it is regarded that if sports stand development

works are to be undertaken across this section of the site, exploratory holes should

be constructed in order to enable this risk to be appropriately assessed.


APPENDIX 1

SITE LOCATION PLANS AND AERIAL PHOTOGRAPH


APPENDIX 2

WALK OVER SURVEY PHOTOGRAPHS


APPENDIX 3

HISTORICAL ORDNANCE SURVEY MAPS


APPENDIX 4

ENVIRONMENTAL MAPS


APPENDIX 5

LANDMARK ENVIRONMENTAL REPORT


APPENDIX 6

EXTRACTS OF BGS GEOLOGICAL MAP AND BOREHOLE LOGS


APPENDIX 7

EXTRACTS OF HPA AND BRE211 RADON ATLAS FOR ENGLAND AND WALES


APPENDIX 8

COAL AUTHORITY MINING REPORT


APPENDIX 9

FACTUAL INFORMATION RELATING TO PREVIOUS SITE INVESTIGATION WORKS


APPENDIX 10

PROPOSED DEVELOPMENT PLAN

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