A50 Growth Corridor Scheme Phase I Geo- environmental and Geotechnical Assessment Final 47069770 May 2014 Prepared for: Staffordshire County Council
UNITED KINGDOM & IRELAND
A50 Growth Corridor – Staffordshire County Council
Rev Date Details Prepared by Checked by Approved by
Victor Ojambati David Evans David Cragg 1 May 2014 For Client Comment Graduate Geo- Principal Geo- environmental environmental Technical Director Engineer Scientist
Victor Ojambati David Evans David Cragg 2 May 2014 Final Graduate Geo- Principal Geo- environmental environmental Technical Director Engineer Scientist
This document has been prepared in accordance with the scope of URS Infrastructure & Environment UK Limited’s appointment with its client and is subject to the terms of that appointment. It is addressed to and for the sole and confidential use and reliance of URS Infrastructure & Environment UK Limited’s client. URS Infrastructure & Environment UK Limited accepts no liability for any use of this document other than by its client and only for the purposes for which it was prepared and provided. No person other than the client may copy (in whole or in part) use or rely on the contents of this document, without the prior written permission of the Company Secretary of URS Infrastructure & Environment UK Limited. Any advice, opinions, or recommendations within this document should be read and relied upon only in the context of the document as a whole. The contents of this document do not provide legal or tax advice or opinion.
© URS Infrastructure & Environment UK Limited 2014
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TABLE OF CONTENTS 1. INTRODUCTION ...... 1 1.1 Purpose of Report ...... 1 1.2 Proposed Development ...... 1 1.3 Information Sources ...... 1
2. ENVIRONMENTAL SETTING ...... 3
2.1 Location ...... 3 2.2 Hydrology ...... 3 2.3 Geology ...... 3 2.3.1 Made Ground ...... 3 2.3.2 Superficial Deposits...... 3 2.3.3 Solid Geology ...... 4 2.3.4 Geological Faults ...... 4 2.3.5 Potential for Natural Ground Hazards ...... 4 2.4 Soils ...... 4 2.5 Mining ...... 5 2.6 Hydrogeology ...... 5
3. SUMMARY OF ENVIRONMENTAL INFORMATION ...... 7
4. REVIEW OF HISTORICAL DATA REPORT ...... 11
5. CONCEPTUAL SITE MODEL ...... 13
6. ENVIRONMENTAL RISK ASSESSMENT ...... 16
6.1 General ...... 16 6.2 Risk Assessment Principles ...... 16 6.3 Evaluation of Risk ...... 17 6.3.1 General Risk Assessment ...... 17 6.4 Evaluation of Risks to Future Site Users...... 18 6.5 Evaluation of Risks to Controlled Waters ...... 19 6.6 Evaluation of Risks to Development Infrastructure ...... 19 6.7 Evaluation of Risks to Construction Workers ...... 19 6.8 Evaluation of Risks to Off Site Receptors ...... 19 6.9 Evaluation of Risks to On site Flora and Fauna ...... 20
7. PRELIMINARY GEOTECHNICAL APPRAISAL ...... 21
8. CONCLUSIONS & RECOMMENDATIONS ...... 23
9. REFERENCES ...... 24
APPENDIX A ENVIROCHECK REPORT (55377518_1_1 13TH APRIL 2014)
FIGURES DRAWING 47069770/DS/01 SITE LOCATION PLAN
DRAWING CDX8690/P/02 SCHEME EXTENTS
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TABLE OF TABLES TABLE 1 POTENTIAL GROUND STABILITY HAZARDS ...... 4 TABLE 2 BGS RECORDED MINERAL SITES ...... 5
TABLE 3 ABSTRACTION LICENSES ...... 7
TABLE 4 DISCHARGE CONSENTS ...... 7
TABLE 5 POLLUTION INCIDENTS TO CONTROLLED WATERS ..... 8
TABLE 6 REVIEW OF HISTORICAL DATA REPORT...... 11
TABLE 7 DESCRIPTION OF POTENTIAL SOURCES...... 14
TABLE 8 DESCRIPTION OF POTENTIAL RECEPTORS ...... 14
TABLE 9 DESCRIPTION OF POTENTIAL PATHWAYS ...... 15
TABLE 10 POTENTIAL POLLUTANT LINKAGES ...... 15
TABLE 11 SEVERITY OF RISK ...... 16
TABLE 12 PROBABILITY OF RISK OCCURRING ...... 17
TABLE 13 COMPARISON OF SEVERITY AND PROBABILITY ...... 17
TABLE 14 RISK EVALUATION OF POTENTIAL POLLUTANT LINKAGES ...... 18
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1.1 Purpose of Report
URS was commissioned by Staffordshire County Council to undertake a Phase 1 Geo- environmental & Geotechnical Assessment for the proposed A50 Growth Corridor ‘Project A’ near Uttoxeter, Staffordshire. The location of the site is presented in Drawing 47069770/DS/01. The extent of the proposed scheme is presented in Drawing CDX8690/P/14.
This Phase 1 Assessment report aims to identify potential contamination issues from current and historic land use, which may be related to on and off-site sources. This report will also provide a preliminary assessment of the geotechnical factors which have the potential to affect a future development scheme. In addition and where it is required, further details of any necessary ground investigation and associated monitoring will be provided. The report is to be used as the baseline to support the Land Quality, Geology and Soil Contamination chapter of the Environmental Statement.
This Phase 1 Geo-environmental & Geotechnical assessment will review the existing information. This assessment encompasses the following:
Geological conditions; Hydrology and hydrogeology; Contaminated land; Environmental risk assessment; Geotechnical assessment; and, Outline Ground Investigation Proposals.
1.2 Proposed Development
The A50 Growth Corridor is located to the north of the Staffordshire town of Uttoxeter, in the administrative area of East Staffordshire Borough Council. Staffordshire County Council is leading the A50 Growth Corridor improvement works, which involves upgrade of the A50 between Blythe Bridge (Tean Roundabout) and the Doveridge Bypass.
This will include the closure of the current A50-A522 slip roads and the construction of a completely new junction to the west of Uttoxeter. This new junction, which consists of entry and exit slip roads will provide access to the proposed housing and business park to the south of the A50, and the existing JCB factories to the north of the A50.
1.3 Information Sources
BGS Solid and Drift for Burton Upon Trent (Sheet 140) 1:50,000; BGS map (SK03SE) 1:10,560; BGS Open Geoscience, 2014 (http://www.bgs.ac.uk/opengeoscience); Envirocheck Report, Landmark Group, 16th April 2014, Order No. 55377518_1_1 (Appendix A); Environment Agency Website (http://maps.environment-agency.gov.uk/); DEFRA website ‘MAGIC’ (http://magic.defra.gov.uk/);
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National Soils Resource Institute, (2014) Soil Site Report. Full Soil Report No 553775182 (NGR Sk0734134862)
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2.1 Location
The site is located to the north of the town of Uttoxeter in Staffordshire. The site is centred on national grid co-ordinates SK 407220, 334610 and is shown on Figure 1. The scheme extent plan is shown on Figure 2. The section of road and junction improvement covers approximately 1.5km west to east. The site is approximately 85m to 90m above ordnance datum (aOD) based on spot heights noted on a recent Ordnance Survey map (1:25,000 scale).
A JCB products distribution centre is located to the northwest of the site. There are agricultural properties, including the ‘Anfield House’ and Park’s Farms, in the vicinity of the site. Residential properties are present to the south of the road. A restaurant is present to the west of the point where the A522 crosses the A50. A farm is present to the south of the road at the eastern end of the proposed scheme
2.2 Hydrology
The key hydrological feature in the vicinity of the site is the River Tean, which flows approximately 50-100m to the north of the site boundary. The River Tean is a tributary of the River Dove, which is a tributary of the River Trent. The River Tean flows in an easterly direction into the River Dove. The current Ecological Quality of the River is classed as ‘Moderate’ by the Environment Agency, whilst the current Chemical Quality is classed as ‘Good’. The EA predicted that both the Ecological and Chemical Quality of the River will remain unchanged until at least 2015.
The land in the vicinity of The River Tean on the northern side of the site is mainly located within the Flood Zone 3 on the Environment Agency Flood Map. An issue flows west to east along the northern scheme boundary. The issue then flows into the River Tean.
2.3 Geology
For geological information on the site, the BGS Solid and Drift Maps for Burton upon Trent, (Sheet 140) 1:50,000, and the 1:10,560 scale BGS map SK03SE were reviewed.
2.3.1 Made Ground
Review of the BGS maps and the BGS borehole records from the Envirocheck Report (55377518_1_1), indicates that there is no Made Ground expected to be present on site. However, Made Ground may be encountered on site as a result of the earthworks materials from the A50 construction and the backfill of the former Sand and Gravel pits located to the south of the scheme. If the sand and gravel pits were excavated into the river alluvium there is a possibility that they will contain saturated backfill below the water table. Topsoil with approximately 0.3m thickness was observed from the borehole records.
2.3.2 Superficial Deposits
The BGS Map for Burton upon Trent Solid & Drift (Sheet 140) 1:50,000, indicates that Alluvium Deposits (Clay, Silt, Sand and Gravel) are present across most of the area of the existing A50 road within the site boundary. The Alluvium Deposits are underlain by Glacial Sand and Gravel (Glaciofluvial Deposits). The Glaciofluvial Deposits are more prominent in the centre of the scheme along the A50 road. An area in the western side of the site (between A50 and A522) and to the south of the A50 road are shown to be underlain by Till (Boulder Clay) deposits. The current route of the A50 is on the same level as surrounding land.
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2.3.3 Solid Geology
The BGS Solid Map for Burton upon Trent Solid & Drift (Sheet 140) 1:50,000 and the 1:10,560 scale BGS map SK03SE indicated that the underlying solid geology is comprised of Mercia Mudstone Group – Mudstone (formerly Keuper Marl). The Mercia Mudstone Group is described by the British Geological Survey as ‘dominantly red, less commonly green-grey, mudstones and subordinate siltstones with thick halite-bearing units in some basinal areas; thin beds of gypsum/anhydrite widespread; sandstones are also present’.
2.3.4 Geological Faults
No geological faults have been noted within or in close vicinity (ca. 1km) to the site.
2.3.5 Potential for Natural Ground Hazards
The Envirocheck Report (55377518_1_1) has been reviewed to determine the potential for Natural Ground Movement within a nominal 500m corridor. The range of Hazard Potentials used to describe the site is presented in Table 1 below.
Table 1 Potential Ground Stability Hazards
Hazard Hazard Potential on Site
Potential for Collapsible Ground Stability Hazards No Hazard to Very Low
Potential for Compressible Ground Stability Hazards No Hazard to Moderate
Potential for Ground Dissolution Stability Hazards No Hazard
Potential for Landslide Ground Stability Hazards Very Low to Low
Potential for Running Sand Ground Stability Hazards No Hazard to Low
Potential for Shrinking or Swelling Clay Ground Stability Hazards No Hazard to Low
2.4 Soils
The National Soil Resources Institute (NSRI) Soils Site Report and the DEFRA’s Magic website were reviewed for the site soils information.
It is noted in the (NSRI) Soils Site Report that the soils spatial distribution within the scheme boundary is of the Wigton Moor soil association. This is described as ‘permeable fine and coarse loamy soils variably affected by groundwater. The drier soils being on slightly raised sites’. The soils within the boundary scheme are described as naturally wet loamy soils with naturally high groundwater, with low fertility.
The soils have low potential for ground movement and minor flood vulnerability risk. Under the Groundwater Protection Policy (GWPP) Soil Leaching Class, they are noted as ‘soils of high leaching potential, which readily transmit liquid discharges because they are either shallow, or susceptible to rapid bypass flow directly to rock, gravel or groundwater’.
The Agricultural Land Classification for most of the scheme extent along the A50 road is classed as Grade 4 (Poor). The agricultural land in the north and southwest areas of the scheme are classed as Grade 3 (Good to Moderate). The land in the southeast area of the scheme is classed Non-Agricultural Land (predominantly in urban use).
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2.5 Mining
The site is located within a Mineral Consultation Area according to the BGS Revision of Mineral Consultation Areas for Staffordshire County Council. There are five (5) BGS Recorded Mineral Sites within 250m of the site as presented in Table 2. These are opencast mines for Sand and Gravel and Common Clay and Shale. All the mineral sites have ceased operation.
The site is not within a Coal Mining area.
Table 2 BGS Recorded Mineral Sites
Distance Site Name Location Type Commodity Status
Sand and 0m Park’s Farm Uttoxeter, Staffordshire Opencast Ceased Gravel
Sand and 39m (S) The Park Uttoxeter, Staffordshire Opencast Ceased Gravel
Common Clay 109m (N) Stramshall Stramshall, Uttoxeter Opencast Ceased and Shale
Sand and 202m (NE) Stramshall Stramshall, Uttoxeter Opencast Ceased Gravel
Sand and 221m (NE) Stramshall Stramshall, Uttoxeter Opencast Ceased Gravel
2.6 Hydrogeology
The underlying Alluvium and Glacial Sand and Gravel Deposits (Superficial Deposits), which are present along the A50 route are classified as Secondary B Aquifer according to the Envirocheck Report. The Till (Boulder Clay) deposits which underlie the southern part of the site and the area between A50 and A522 roads are classed as Unproductive Strata.
The Environment Agency defines Secondary B aquifers as ‘predominantly lower permeability layers which may store and yield limited amounts of groundwater due to localised features such as fissures, thin permeable horizons and weathering. These are generally the water- bearing parts of the former non-aquifers’.
The Unproductive Strata are defined as “rock layers or drift deposits with low permeability that has negligible significance for water supply or river base flow”.
The underlying bedrock of the Mercia Mudstone Group in the area of the site is classified by the Environment Agency as a Secondary B aquifer. This type of aquifer is described by the EA as ‘predominantly lower permeability layers which may store and yield limited amounts of groundwater due to localised features such as fissures, thin permeable horizons and weathering’. This type of aquifer is noted by the EA as generally the water-bearing parts of the former non-aquifers. The Mercia Mudstone sequence contains thin siltstone / sandstone bands known as ‘skerries’, which are thin permeable horizons and which can be water bearing.
The current Ecological Quality and Chemical Quality of the groundwater is classed ‘Good’ by the Environment Agency. It is predicted that both the groundwater Ecological and Chemical Quality will remain unchanged until at least 2015.
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There are no Source Protection Zones located within 500m of the site. However, a Source Protection Zone III (Total Catchment) is located 744m to the NW of the site. This SPZ is associated with the Tarporley Siltstone Formation. The Total Catchment Zone is defined by the EA as ‘the area around a source within which all groundwater recharge is presumed to be discharged at the source. In confined aquifers, the source catchment may be displaced some distance from the source’.
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3.1 Water Abstractions
Information obtained from the Envirocheck report indicates that there are no groundwater abstraction points within 500m. However, there are four groundwater abstraction points within 2km of the site boundary. The details are listed in Table 3. Three of the abstraction points abstract water from groundwater source.
Table 3 Abstraction Licenses
Permit Start Distance Operator Location Abstraction Permit End Data Date
820m Deggs Leasows General Farming th Mr T Tideswell 16 Nov. 1965 Not Supplied (NW) Farm, Uttoxeter and Domestic
1053m Bramshall Park General Agriculture: th Mr T R Statham 27 May 1971 Not Supplied (SW) Farm Spray Irrigation
1053m Bramshall Park General Farming th Mr T R Statham 27 May 1971 Not Supplied (SW) Farm and Domestic
Borough of East Bramshall Municipal Grounds: 1232m th Staffordshire Recreation Lake and Pond 18 Aug. 1995 Not Supplied (SE) Council Ground Throughflow
3.2 Discharge Consents
The Envirocheck report (55377518_1_1) indicates that there is one discharge consent within the boundary of the scheme and additionally five within 500m of the scheme boundary. The details of these abstractions within 500m are given in Table 4 below.
Table 4 Discharge Consents
Receiving Distance Operator Location Discharge Type Status Water
Park View, Uttoxeter Giltan 0m Road, Beamhurst, Sewage Effluent Not Supplied Not Supplied Homes Ltd Uttoxeter
Longmead House, Sewage Discharges 27m Steven Westfield House, – Final/Treated Groundwaters New Consent (S) Russell Parks Cottage, New Effluent – Not water via Soakaway Road, Uttoxeter company
Sewage Discharges Pre National Rivers Tributary of 100m Trust Inns The Parks, New – Final/Treated Authority Legislation the River (S) Limited Road, Uttoxeter Effluent – Not water where issue date Tean company <01/09/1989
Pre National Rivers Severn Trent Kimberly Drive, Public Sewage: 200m Park Brook Authority Legislation Water Parks Cottage Farm Storm Sewage (S) (River Tean) where issue date Limited Estate, Uttoxeter Overflow <01/09/1989
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Receiving Distance Operator Location Discharge Type Status Water
Severn Trent Public Sewage: 200m Kimberly Drive, Varied under EPR Water Storm Sewage Local Ditch (S) Uttoxeter 2010 Limited Overflow
Sewage Discharges Pre National Rivers 270m J A Lawn Farm, – Final/Treated Authority Legislation Not Defined (NE) Hemingway Stramshall, Uttoxeter Effluent – Not water where issue date company <01/09/1989
3.3 Pollution Incidents to Controlled Waters
The Envirocheck report (55377518_1_1) indicates that five pollution incidents to controlled waters have been reported within a radius of 1km from the site. Two of these incidents are within the site boundary, between 1995 and 1999. The details for these pollution incidents are given in Table 5 below.
Table 5 Pollution Incidents to Controlled Waters
Cause of Receiving Distance Date Pollutant Severity Incident Water
24th August Sewage – Septic Tank Treatment System Category 3 – Minor 0m Not Given 1999 Effluent Failure Incident
22nd August Oils – Diesel Accidental Category 3 – Minor 0m Watercourse 1995 (Including Agricultural) Spillage/Leakage Incident
25th February Accidental Category 3 – Minor 246m (NW) Organic Waste – Milk Not Given 1999 Spillage/Leakage Incident
th Leaking Tank Category 3 – Minor 329m (SE) 17 June 1998 Oils – Petrol Not Given Incident
th Sewage – Septic Tank Leaking Category 3 – Minor 952m (SE) 30 May 1996 Groundwater Effluent Underground Pipe Incident
3.4 Local Authority Pollution Prevention and Controls
There are five sites which are operated under a Local Authority Pollution Prevention and Control permit within 500m of the site, two are associated with the JCB distribution depot and 3 relate to the petrol station adjacent to the eastern extent of the proposed scheme. There are no sites which operated: under the Integrated Pollution Controls; under the Integrated Pollution and Prevention and Control; under Local Authority Integrated Pollution Prevention and Control and no Local Authority Pollution Prevention and Control Enforcement permits within 1km of the Site.
3.5 Environmental Prosecutions
There has been no Prosecutions Relating to Authorised Processes within 1km of the site.
3.6 Potentially Hazardous Sites
There are no sites within 1km of the site, which are classed under the following headings within the Envirocheck report (55377518_1_1): Control of Major Accident Hazards Sites
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(COMAH), Explosive Sites, Notification of Installations Handling Hazardous Substances (NIHHS), Planning Hazardous Substance Consents and Planning Hazardous Substance Enforcements.
3.7 Contemporary Trade Land Use
There are six Contemporary Trade Directory Entries listed within the Envirocheck report (55377518_1_1) located within 250m of the site, four of which are within the site boundary. Two of the Six are noted as active. These encompass the following classifications:
New Road Garage (Car Dealers) - Onsite Dust Fairies (Cleaning Services – Domestic) – 74m (E) In addition, there are three fuel station entries adjacent to the site boundary listed in the Envirocheck report (55377518_1_1), with only one of them still operating.
3.8 Registered Landfill Sites
There are no Registered Landfills sites within 1km of the site presented within the Envirocheck report (55377518_1_1).
3.9 Historic Landfill Sites
There is one Historic Landfill site within 1km of the site presented within the Envirocheck report (55377518_1_1). This received Industrial Waste and it is located 991m (S) of the site. The Last Input Date was 31st December 1958.
3.10 Licensed Waste Management Facilities
There are no Licensed Waste Management Facilities within 1km of the site as presented within the Envirocheck report (55377518_1_1).
3.11 Local Authority Recorded Landfill Sites
There are no Local Authority Recorded Landfill sites within 1km of the site as presented within the Envirocheck report (55377518_1_1).
3.12 Registered Waste Treatment or Disposal Sites
No Registered Waste Treatment or Disposal Sites are noted to be present within 1km of the site as presented within the Envirocheck report (55377518_1_1).
3.13 Radon
The Envirocheck report (55377518_1_1) indicates that the site is ‘in a lower probability radon area, as less than 1% of homes are above the action level’. This data is supplied by the British Geological Survey.
It is also noted in the Envirocheck report that “No radon protection measures are necessary in the construction of new dwellings or extensions” anywhere within the site boundary. This is based on data supplied by the British Geological Survey.
This is for information and relevant, only, if the use of the site changes to residential in future.
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3.14 Sensitive Land Uses
The site is located within a Nitrate Vulnerable Zone (NVZ).
A field to the south of the road scheme centred on NGR 407571, 334678 is identified as ‘undetermined grassland BAP Priority Habitat (England)’.
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A summary of historical land uses for the site are presented in Table 6. The historical ordnance survey maps were not available and only the information presented in the Historical Data Report Datasheet of the Envirocheck Report (55377518_1_1) were used. URS cannot confirm that all relevant features have been identified as we have not viewed the historical OS maps. The table describes significant changes in industry and land development within the site boundary from 1889 to present day, and significant developments within 250m of the site boundary. This discussion of historical land use is focused primarily on potentially contaminative land use.
Table 6 describes the main features present on and in the vicinity of the development site. Where dates are given, these refer to dates shown in the Envirocheck Report, and do not necessarily refer to the exact date of operation of any particular facility.
Table 6 Review of Historical Data Report
Description Date Scale Within Site Boundary Outside Site Boundary
A feature identified as an ‘Old Canal’ is identified on the eastern half of the general route of the current A50, Quarrying of sand & clay around the Park’s adjacent to the southern side of the Farm located to the south of the current A50 to road and crosses the road and heads 1889 1:10,560 the west of the site boundary. Clay bricks and north. The ‘Old Canal’ is identified tiles factory located on New Road to the east within the Envirocheck Historical Data of the site boundary. Report as an infilled feature. The area adjacent to the ‘Old Canal’ appears to be in agricultural use.
Potentially infilled land (water) noted between A50 and A522 (around Ch. 700) at eastern side of the site. This is 1:10,560 Four additional sand & clay quarries located to 1901 described as ‘Unknown Filled Ground the north of River Tean. (pond, marsh, river, stream, dock etc). No other significant changes are noted.
Only one sand and clay quarry now present at The potentially infilled land is no longer the north of River Tean. The Clay bricks and 1:10,560 1924 present. No other significant changes tiles factory on the New Road is no longer are noted. present. No other significant changes are noted.
Potentially infilled land (water) present 1:10,560 No significant changes are noted. 1938 on the A50 road (around Ch. 700). No significant changes are noted.
The potentially infilled land is no longer No significant changes are noted. 1955 1:10,560 present. No other significant changes are noted.
Potentially Infilled Lands (Non-Water) described as ‘Unknown Filled Ground (Pit, Tanks noted on A50 (around Ch. 850) quarry etc)’ not around the Park’s Farm and 1:2,500 1976 No other significant changes are very close to the south of New Road (around 1:10,000 noted. MC11). Electrical Sub Station Facilities present to the south east of the site. The sand and clay quarries are no longer noted.
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Date Scale Description
Gas monitoring facilities present to the south 1981 1:2,500 No significant changes are noted. east of the site.
The tanks on A50 are no longer 1987 1:2,500 present. No other significant changes No significant changes noted. noted.
Five potentially infilled lands (Non-Water) are seen to the north east of River Tean. The 1992 1:10,000 No significant changes noted. electrical substation and gas monitoring facilities are no longer present.
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Current legislation relating to contaminated land in the UK is contained within Part 2A of the Environmental Protection Act 1990, which was inserted by section 57 of the Environment Act 1995, and by section 86 of the Water Act 2003.
The “suitable for use” approach is adopted for the assessment of contaminated land where remedial measures are only undertaken where unacceptable risks to human health or the environment are realised taking into account the use (or proposed use) of the land in question and the environmental setting.
Current best practice recommends that the determination of health hazards due to contaminated land is based on the principle of risk assessment, as outlined in Part 2A of the Environmental Protection Act 1990.
The risk assessment process for the environmental contaminants is based on a source- pathway-receptor analysis. These terms can be defined as follows:
Source: Hazardous substance that has the potential to cause adverse impacts;
Pathway: Route whereby a hazardous substance may come into contact with the receptor: examples include ingestion of contaminated soil and leaching of contaminants from soil into watercourses;
Receptor: Target that may be affected by contamination: examples include human occupants/users of site, water resources (surface waters or groundwater), or structures.
For a risk to be present, there must be a viable contaminant linkage; i.e. a mechanism whereby a source impacts on a sensitive receptor via a pathway.
The following sections detail the conceptual site model which has been developed for the site with the view to assessing the potential risks during construction and upon completion of the proposed new development. The potential sources of contamination, potential receptors and potential pollutant pathways are identified (and are presented in Tables 7 to 9) for the site. The associated contaminant linkages between these sources, pathways and receptors are presented in Table 10.
5.1 Sources of Potential Contamination
Table 7 lists sources of potential contamination at the site of the proposed development.
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Table 7 Description of Potential Sources
Potential Source Description
Made Ground Made ground (infilled canal) is present along the southern side of the A50, eastern half of Project A. The infilled canal crosses the route of the A50. Made Ground could also be present from the previous earthworks for the A50, the quarrying and farming activities in the vicinity of the site vicinity.
Natural Strata The natural strata will consist of Alluvium, Glaciofluvial and Till deposits overlying Mercia Mudstone Group – Mudstone [formerly Keuper Marl].
Soil Leachate Potential contaminants may be leached from possible made ground sources if present at the site.
Groundwater Shallow groundwater is likely to be present within the Glaciofluvial deposits.
Ground Gas Concentrations of ground gases (methane and carbon dioxide) may originate from Made Ground if present. Ground gases are also likely to be present due to the natural Glaciofluvial deposit [dependent on the organic matter content of these deposits].
Offsite Sources Leaks, spills and emissions from surrounding sources e.g. industrial park present to the northwest of the side boundary. A petrol filling station is located adjacent to the eastern boundary of the scheme extent.
5.2 Potential Receptors
Table 8 lists potential receptors at the site of the proposed development.
Table 8 Description of Potential Receptors
Potential Receptor Description
Future Site Users Road users, pedestrians, maintenance workers.
Controlled Waters River Tean 50-100m to the north of the scheme. Water wells located in the vicinity of the site, nearest water well is located ca.1km to the west of scheme western extent. The underlying Secondary B aquifers.
Development Concrete is a receptor of chemical aggressivity in contaminated soils with a low pH and high Infrastructure sulphate concentrations.
Construction Exposures experienced by construction workers are much less than for future site users due workers to the limited period of exposure. Construction workers are therefore not considered as sensitive receptors.
Off-site receptors This includes visitors to and workers of nearby commercial / industrial properties to the northwest the site. Residents of properties to the south and southeast of the site. Users of water wells located in the vicinity of the site.
Flora and Fauna There are landscaped areas currently to the north and south of the site.
5.3 Potential Pathways
Table 9 provides a summary of the potential pathways associated with identified sources considered most appropriate to the site in its developed condition:
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Table 9 Description of Potential Pathways
Potential Pathway Description
Dermal contact with contaminated soils, soil derived dust, Dermal Contact. soil leachate and perched groundwater. Soil Pathway Direct contact of building materials with contaminated Direct Contact. Including the following sources: soils, soil leachate and perched groundwater. Made Ground; Ingestion. Direct or indirect ingestion of soil and soil derived dust. Soil Derived Leachate. Inhalation of soil derived dust, organic vapours or ground Inhalation. generated gas.
Rainfall Infiltration & Vertical / Lateral Rainfall infiltration can generate and mobilise soil-derived Groundwater Pathways migration via leachate impacting on surface waters and groundwater. permeable strata Including the following sources: Groundwater within the site is likely to flow towards River and service Tean to the north of the proposed road scheme. Soil Leachate; conduits. Perched Groundwater. Lateral Migration As well as being a receptor, aquifers allow transportation through Aquifer. of contaminants through the permeable strata.
Gas Pathways Vertical / Lateral Permeable strata and service trenches may allow Migration via Including the following sources: transportation of ground gases. permeable strata. Ground gas.
5.4 Potential Contaminant Linkages
The potential contaminant linkages and associated risks identified for the site in its proposed use as a road scheme development with associated infrastructure and landscaping are summarised in Table 10.
Table 10 Potential Pollutant linkages
Source Pathway Receptor
Ingestion of contaminated soil Future Site Users. Diffuse metal, inorganic Inhalation/ingestion of soil derived Construction Workers. and organic dust. Development Infrastructure. contamination within the Made Ground. Inhalation of organic vapours Flora and Fauna. Direct contact with soils/dusts. Off-Site Receptors.
Leaching into groundwater and Surface Watercourses. Generated leachate migration to surface watercourses. Perched Groundwater. from Made Ground. Plant uptake. Off-site Flora and Fauna.
River Tean. Contaminants in Deeper Groundwater (in Secondary Migration and diffusion. groundwater. ‘B’ Aquifer). Water Wells. Future Site Users. Construction Workers. Migration and diffusion via permeable Ground Gases. Flora and Fauna. strata. Development Infrastructure. Off-site receptors.
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6.1 General
From information obtained for the desk study, a conceptual site model was developed for the site, as detailed in Section 6. Based on the subsequent risk assessment, the various components of the model are discussed in the following sections and take into account the site in its current condition and potential future use as a road scheme. An assessment of the various contaminant linkages is presented in Table 14.
6.2 Risk Assessment Principles
Current best practice recommends that the determination of hazards due to contaminated land is based on the principle of risk assessment, as outlined in Part 2A of the Environmental Protection Act 1990.
For a risk to be present, there must be a viable contaminant linkage; i.e. a mechanism whereby a source impacts on a sensitive receptor via a pathway. The potential contaminant linkages that have been identified for this site are presented in section 6.
Assessments of risks associated with each of these contaminant linkages, following review of available information for the site is discussed in the following sections.
Using criteria broadly based on those presented in Section 6.3 of the CIRIA Report “Contaminated Land Risk Assessment: A Guide to Good Practice” (CIRIA Report C552) the magnitude of the risk associated with potential contamination at the site has been assessed.
To do this an estimate is made of: the potential severity of the risk; the likelihood of the risk occurring. The severity of the risk is classified according to the criteria in Table 11.
Table 11 Severity of risk
Severity Description
Severe Acute risks to human health likely to result in “significant harm” (e.g. very high concentrations of contaminants / ground gases). Catastrophic damage to buildings/property (e.g. by explosion, sites with high gassing potential, extensive VOC contamination). Major pollution of controlled waters (e.g. surface watercourses or Principal aquifers/source protection zones) Short term risk to a particular ecosystem.
Medium Chronic (long-term) risk to human health likely to result in “significant harm” (e.g. elevated concentration of contaminants/ground gases). Pollution of sensitive controlled waters (e.g. surface watercourses or Principal / Secondary aquifers). Significant effects on sensitive ecosystems or species.
Mild Pollution of non-sensitive waters (e.g. smaller surface watercourses or Unproductive Strata). Significant damage to crops, buildings, structures or services (e.g. by explosion, sites with medium gassing potential, elevated concentrations of contaminants).
Minor Non-permanent human health effects (requirement for protective equipment during site works to mitigate health effects). Damage to non-sensitive ecosystems or species. Minor (easily repairable) damage to buildings, structures or services (e.g. by explosion, sites with low gassing potential).
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The probability of the risk occurring is classified according to criteria given in Table 12 below.
Table 12 Probability of Risk Occurring
Probability Description
Contaminant linkage may be present that appears very likely in the short-term and risk is almost High likelihood certain to occur in the long term, or there is evidence of harm to the receptor
Likely Contaminant linkage may be present, and it is probable that the risk will occur over the long term
Contaminant linkage may be present and there is a possibility of the risk occurring, although Low likelihood there is no certainty that it will do so.
Contaminant linkage may be present but the circumstances under which harm would occur even Unlikely in the long-term are improbable.
An overall evaluation of the level of risk is gained from a comparison of the severity and probability, as shown in Table 13 below.
Table 13 Comparison of Severity and Probability
Severity
Severe Medium Mild Minor
High Likelihood Very High High Moderate Moderate/Low
Likely High Moderate Moderate/Low Low
Low Likelihood Moderate Moderate/Low Low Very Low Probability
Unlikely Moderate/Low Low Very Low Very Low
6.3 Evaluation of Risk
6.3.1 General Risk Assessment
An evaluation of the potential risks associated with the identified sources at the site to the various receptors is discussed and presented in the following section. The level of risk is determined based on the current condition of the site (i.e. the effects of mitigation measures are not included) and takes into account the outline development proposals.
The evaluation includes an assessment of the significance of the potential contaminant linkages. Where it is considered that a particular contaminant linkage is not plausible in the context of the site and the proposed development, the overall risk is determined as very low.
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Table 14 Risk Evaluation of Potential Pollutant Linkages
Potential Risk Evaluation Source Pathway Receptor Contaminant Linkage Severity Source Pathway
Direct contact/ ingestion / Future Site Users Y Minor Low Very Low inhalation likelihood
Direct contact/ ingestion / Construction Workers Y Mild Low Low inhalation likelihood Contaminants Infiltration/ Migration Controlled Waters Y Mild Low Low in Made likelihood Ground / Direct contact Development Y Mild Low Low Natural Strata Infrastructure likelihood Inhalation of vapours/ Off-Site Receptors Y Minor Low Very Low dusts likelihood Direct contact / uptake Flora & Fauna Y Mild Low Low likelihood Direct contact/ ingestion / Future Site Users Y Minor Low Very Low inhalation likelihood
Direct contact/ ingestion / Construction Workers Y Mild Low Low inhalation likelihood
Infiltration/ Migration Controlled Waters Y Mild Low Low likelihood
Contaminants Infiltration/ Migration Water Wells Y Mild Low Low in Leachate / likelihood Groundwater Direct contact Development Y Minor Low Very Low Infrastructure likelihood
Infiltration/ Off-Site Off-Site Receptors Y Minor Low Very Low Migration likelihood
Direct contact / uptake Flora & Fauna Y Mild Low Low likelihood
Migration & Inhalation / Future Site Users Y Mild Low Low Explosion likelihood
Migration & Inhalation / Construction Workers Y Minor Low Very Low Explosion likelihood
Migration & Explosion Development Y Minor Low Very Low Ground Gases Infrastructure likelihood
Migration & Inhalation / Off-Site Receptors Y Minor Low Very Low Explosion likelihood
Direct contact/ uptake Flora & Fauna Y Minor Low Very Low likelihood
6.4 Evaluation of Risks to Future Site Users
The potential exposure of the future users of the site by direct contact to likely contaminants in the ground is very low, since the road will be paved and direct contact will be limited. Made ground is likely to be present along the southern side of the A50 and crosses the road to head
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north. Therefore, the risk to future site users from direct contact with the underlying soils is considered low.
The risk to future site users from direct contact with contaminated leachate or groundwater is considered low. It is considered there is a low likelihood of future site users coming into contact with leachate or groundwater at the site.
There is a low potential risk to future site users from ground gas sourced from the underlying Superficial (Glaciofluvial) deposits and Made Ground. Review of borehole records does not indicate the presence of Peat within the ground which can lead to ground gas generation. However, other natural sources of organic matter may be present.
There is potential risk to maintenance workers entering confined spaces, such as services trenches. It is considered that the risk to maintenance workers will be low as it is assumed they will be wearing appropriate PPE suitable for the task and monitoring the atmospheric conditions, and that entry into underground structures or excavations should comply with confined space legislation and assessed prior to entry.
It should be noted that to date, no ground gas monitoring has been undertaken at the site. Ground gas monitoring would be required to assess the gas regime for the site.
6.5 Evaluation of Risks to Controlled Waters
The risks to controlled waters are considered to be low. Made ground is understood to be present along the southern side of the A50. In terms of groundwater, the risk is considered to be low as the Till deposit underlying part of the site is classified by the EA as an Unproductive Strata and the Mercia Mudstone Group is classified by the EA as a Secondary ‘B’ aquifer. There are no source protection zones within 10km of the site and there are no groundwater abstraction points within 500m of the site boundary.
6.6 Evaluation of Risks to Development Infrastructure
The risks to the development infrastructure from soil, leachate and groundwater contaminants have been classed as very low. It is assumed that any potential risks would be mitigated by using materials appropriate for aggressive ground conditions, where identified, at the site.
6.7 Evaluation of Risks to Construction Workers
The assessment has identified a low risk to construction workers at the site. This takes into consideration that whilst construction/site workers might be expected to come into contact with soils, the use of personal protective equipment will be a pre-requisite to them being on site.
Prior to work commencing, a health and safety risk assessment should be carried out in accordance with current health and safety regulations. This assessment should cover potential risks to both construction staff and the local population. Based on the findings of this risk assessment, appropriate mitigation measures should be implemented during the course of the earthworks.
It is considered prudent that entry into excavations should comply with confined space legislation and assessed prior to entry.
6.8 Evaluation of Risks to Off Site Receptors
The potential risk to off-site receptors is considered to be very low.
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Any risks to local off-site receptors would be associated with off-site migration of contamination, for instance, in the form of wind-blown dust and / or organic vapours. Exposure via inhalation of dust is considered to be negligible for off-site receptors following development works, and as such there is not considered to be a plausible pollutant linkage. The greatest potential for dust generation will be during the construction phase. Dust generation should be kept to a minimum in accordance with general best practice, as outlined in, for example, “Environmental Good Practice on Site”, 3rd Edition, CIRIA Publication C692. Overall the risks to off-site receptors from on-site soil derived dusts are considered to be Very Low.
6.9 Evaluation of Risks to On site Flora and Fauna
The risks to flora and fauna on the site have been classified as low.
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7.1 General
The site which includes a section of the A50 and A522 roads is currently being used for transportation. There are small areas of agricultural land both to the north and south of the A50.
A number of potential geotechnical issues have been identified that will need to be investigated further and addressed in the design and construction of the proposed new development. These are discussed in the following sections.
7.2 Depth to Rockhead
Review of the BGS borehole records in the vicinity of the site as provided in the Envirocheck Report indicates that the depth to weathered rockhead varies approximately from 11m to 20m below ground level (bgl). Weathered Mudstone was encountered in most of the borehole records reviewed.
Dependent on the anticipated loads that will be placed on any proposed structure e.g. bridges information on depth to rockhead, and the profile of strength with depth in the mudstone, will be required.
7.3 Weak and Compressible Ground
Data from the BGS contained within the Envirocheck Report indicates that the potential for collapsible ground stability hazards ranges from ‘No Hazard’ to ‘Very Low’. There is a ‘No Hazard’ to ‘Moderate’ potential for compressible ground stability hazards at the site. There is no hazard relating to potential for ground dissolution stability. Excavations below the water table may require temporary support and/or suitable dewatering control in some areas.
There is a Very Low to Low potential for landslide ground stability hazards. The potentials for running sand ground stability and shrinking or swelling clay ground stability hazards ranges from ‘No Hazard’ to ‘Low’.
Where alluvial clays / silts, and / or infilled ground are present there is the potential for weak and compressible ground, which would be the subject of intrusive investigation and design assessment at design stage.
7.4 Shallow Groundwater
The review of the BGS borehole records shows that groundwater was encountered at shallow depths (1.4m to 4m bgl) in the vicinity of the scheme. The presence of groundwater at shallow depths may have an effect on any excavation or foundations on the site.
7.5 Buried Foundations
The likelihood of unknown buried foundations being present is low as the site currently contains sections of the A50 and A522 roads, agricultural land and few buildings. If present, buried foundations including potential old pile foundations can represent hard spots within the ground. This can cause delays where they are encountered, unforeseen, in initial foundation ground works as they need to be broken out. When left in place, buried foundations can also promote differential settlement in new structures, leading to cracking and damage to the new construction.
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7.6 Aggressive Ground Conditions
The likelihood of aggressive ground conditions being present at the site is low as the underlying superficial deposits and bedrock (Mercia Mudstone) do not have significant pyrite content. However, the Mercia Mudstone is high in sulphates, please refer to CIRIA document “Engineering in Mercia Mudstone” There is a possibility that Made Ground may be present from the old gravel pits, the infilled former canal along the southern side of the eastern extent of the current A50 and previous construction works on the A50.
If aggressive ground conditions are present, the main hazard and associated risk relates to sulfates and chlorides that, in sufficient quantities, may be aggressive to concrete and steel causing degradation and damage. This can be overcome through the specification of more resistant concrete and anti-corrosion measures on steel, but requires testing and assessment of the soils beneath the site in order to determine the level of risk.
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8.1 Conclusions
The proposed development includes the closure of the current A50-A522 slip roads and the construction of a completely new junction to the west of Uttoxeter. This new junction, which consists of entry and exit slip roads will provide access to the proposed housing and business park to the south of the A50, and the existing and new JCB factories to the north of the A50. The majority of the site is currently covered by macadam hardstanding associated with the A50 and A522 roads. The areas in the vicinity of the roads are well vegetated.
It is considered, based on the information obtained, that geo-environmental risks are low to very low. The potential Made Ground is a likely, but limited, source of ground contamination at the site. There are limited sources of ground gas within the site boundaries which may be associated with Natural Ground or Made Ground if present.
The main geotechnical issues at the site are considered to be the potential compressibility of the alluvial materials; the infill materials associated with the old canal and the former quarries may not have been deposited in an engineered manner; the presence of groundwater at shallow depths and the variation in depth to rockhead over a relatively short distance.
8.2 Recommendations
It is recommended that a ground investigation of the site is undertaken to assess the geo- environmental, and geotechnical ground conditions, with particular attention to the following: Investigate the nature and extent of Made Ground across the site including the infilled canal; Investigate the nature of the underlying natural strata, where present, including determination of in-situ soil properties; Investigate depths to rockhead; Investigate the properties of the Mercia Mudstone within the depth of interest for foundation design; Obtain soil and groundwater samples for chemical testing and geotechnical testing; Install gas and groundwater monitoring wells and undertake monitoring of ground gas concentrations and groundwater levels; Undertake a range of suitable soil, leachate and groundwater chemical tests, including BRE sulfate tests. Any ground investigation would be expected to comprise cable percussion boreholes and machine-dug trial pits. Rotary cored drillholes may be required to sample the Mercia Mudstone within the depth of interest. The most cost effective approach would be to combine the requirements of the geo-environmental and geotechnical assessments into a single investigation.
Following the ground investigation, an interpretative report comprising human health, controlled waters and ground gas risk assessments should be undertaken to fully assess the levels of contamination across the site, to identify mitigation measures where required and make recommendations to allow the redevelopment of the site. This report would also review the geotechnical conditions based on the ground investigation results and provide outline guidance on the need for ground improvement and advice on foundation options, typical allowable bearing pressures and potential settlement ranges for the ground conditions.
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BGS (1982) Burton upon Trent (Sheet 140) Solid and Drift 1:50,000 scale
BGS (1947) Solid and Drift Map (SK03SE) 1:10,560 scale
BGS (2006), Provision of Geological Information and a Revision of Mineral Consultation Areas for Staffordshire County Council.
CIRIA (2010) Environmental Good Practice on site. 3rd Edition, CIRIA Report C692
CIRIA (2001) Contaminated Land Risk Assessment: A Guide to Good Practice. CIRIA Report C552.
Environment Agency (2004) Model Procedures for the Management of Land Contamination, CLR 11.
Landmark Information Group Ltd (2014) Envirocheck Report (Site at 407350, 334970) 55377518_1_1 (16/04/2014)
National Soil Resources Institute (2014) Full Soils Site Report for location 407341E, 334862N, 1km x 1km, National Soil Resources Institute, Cranfield University.
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