southsea and north portsea island coastal flood and erosion risk

Transcription

SOUTHSEA AND NORTH
PORTSEA ISLAND COASTAL
FLOOD AND EROSION RISK
MANAGEMENT SCHEMES
SCOPING STAGE REPORT
Technical Report 5: Contaminated Land
November 2012
Final Report
A partnership project by
Eastern Solent Coastal Partnership
Public Service Plaza
Civic Centre Road
Havant Borough Council
Havant
PO9 2AX
Telephone: +44 2392
Email: [email protected]
Internet: www.escp.org.uk
Document title
Southsea and North Portsea Island Coastal Flood
and Erosion Risk Management Schemes
Scoping Stage Report
Contaminated Land
Document short title
Technical Report 5: Contaminated Land
Status
Version
Date
Client
Final
Draft
1.0
0.1
06 February 2013
Portsmouth City Council
2 | SOUTHSEA AND NORTH PORTSEA ISLAND COASTAL FLOOD AND EROSION RISK MANAGEMENT SCHEMES
Contents
GLOSSARY ........................................................................................................5
1
1.1
1.2
1.3
VISION, AIMS AND OBJECTIVES.............................................................6
The Vision...................................................................................................6
The Aims.....................................................................................................6
The Objectives............................................................................................6
2
2.1
2.2
2.3
INTRODUCTION.........................................................................................7
Background to the Scoping Study...............................................................7
Purpose of the Scoping Study.....................................................................7
Format of the Scoping Study.......................................................................9
3
OBJECTIVE AND FORMAT OF THE TECHNICAL REPORT.................10
3.1 Technical Report Objective.......................................................................10
3.2 Technical Report Format...........................................................................12
4
4.1
4.2
4.3
APPROACH..............................................................................................13
Scoping Stage Scheme Parameters.........................................................13
Working in Partnership..............................................................................15
Links to the Wider Scoping Stage ............................................................16
5
REVIEW OF EXISTING DATA..................................................................17
5.1 PICSS Review . ........................................................................................17
5.2 Scoping Stage Data Collation and Review...............................................17
6
SITE LOCATION AND LAND USE . ........................................................18
6.1 Current Land Use......................................................................................18
6.2 Former Land Use (Historical Map Review)...............................................21
7
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
ENVIRONMENTAL SETTING...................................................................27
Published Geology ...................................................................................27
Coal Mining Affected Areas and Ground Stability ....................................30
Hydrogeology and Groundwater Vulnerability . ........................................30
Hydrology..................................................................................................31
Flood Risk ................................................................................................33
Environmentally Sensitive Land Uses . ....................................................33
Radon Gas ...............................................................................................33
Underground Utilities.................................................................................34
8
AUTHORISATIONS, CONSENTS & LICENCES FROM REGULATORY
AUTHORITIES..........................................................................................35
8.1 Flood Cell 1 – Southsea............................................................................35
8.2 Flood Cell 2 – Fraser Battery/ Eastney.....................................................36
8.3 Flood Cell 4 – North Portsea Island..........................................................37
Technical Report 5: Contaminated Land | 3
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
9.11
EXISTING CONTAMINATED LAND INVESTIGATION REPORTS..........41
PICSS Contamination/Risk Assessment Report.......................................41
Reports from the Portsmouth City Council Contaminated Land Archive...42
Canoe Lake...............................................................................................44
The Glory Hole, Eastney and Remediation of the Eastney Barracks
Married Quarters (within Flood Cell 2)......................................................45
Tangier Road Ground Investigation (adjacent to Flood Cell 4).................48
Kendalls Wharf (within Flood Cell 4).........................................................50
H&S Aviation Site (adjacent to Flood Cell 4).............................................51
Alexandra Park (within Flood Cell 4).........................................................52
Horsea Allotments (within Flood Cell 4)....................................................53
Tipner Quay (adjacent to Flood Cell 4).....................................................54
Former HMS Phoenix Site, Matapan Road, Stamshaw, Portsmouth
(partially within Flood Cell 4).....................................................................56
10
INITIAL CONCEPTUAL SITE MODEL AND PRELIMINARY RISK
ASSESSMENT ........................................................................................58
10.1 Conceptual Site Model..............................................................................58
10.2 Summary of Pollutant Linkages and Preliminary Qualitative Risk
Assessment...............................................................................................62
11 CONCLUSIONS AND RECOMMENDATIONS.........................................68
11.1 Conclusions . ............................................................................................68
11.2 Recommendations....................................................................................69
12
BIBLIOGRAPHY.......................................................................................74
Annex 1: Report Limitations..........................................................75
Annex 2: Figures................................................................................76
Annex 3: Envirocheck Report......................................................77
Annex 4: Outputs from the PCC Contaminated Land Archive Search..................................................................................78
GLOSSARY
AEP
Annual Exceedence Probability (of flooding)
BGS
British Geological Survey
cSAC
Candidate Special Area of Conservation
DETR
Former Department of the Environment Transport and the Regions
EIA
Environmental Impact Assessment
FDGiA
Flood Defence Grant in Aid
ICRCL
Interdepartmental Committee on the Redevelopment of
Contaminated Land
LPRG
Large Project Review Group
MoD
Ministry of Defence
PAH
Polycyclic Aromatic Hydrocarbon
PAR
Project Appraisal Report
PCB
Polychlorinated Biphenyl
PRBD
Portsmouth River Basin District
PCC
Portsmouth City Council
PICSS
Portsea Island Coastal Strategy Study
SAC
Special Area of Conservation
SoP
Standard of Protection
SPA
Special Protection Area
SPOSH
Significant Possibility of Significant Harm
SSSI
Site of Special Scientific Interest
StAR
Strategy Appraisal Report
TPH
Total Petroleum Hydrocarbons
WFD
Water Framework Directive
1
VISION, AIMS AND OBJECTIVES
1.1 The Vision
The vision for this and subsequent phases of the Southsea and North
Portsea Island Coastal Flood and Erosion Risk Management Schemes is to:
“Ensure the sustainable future of the City of Portsmouth by managing
coastal flood and erosion risk.”
1.2 The Aims
We will achieve this vision by:
1. Working together with our partners;
2. Providing cost effective methods for adapting to climate change;
3. Recognising the importance of communities, cultural heritage and the
environment;
4. Maximising funding and contributions.
We will use this opportunity to explore and deliver broader benefits to
shape the future of Portsmouth
1.3 The Objectives
The objectives of the next phase of the project are to:
●● Manage the risk of flooding and coastal erosion to people and their
property, now and in the future;
●● Develop and prepare an adaptable flood and coastal risk management
scheme to provide a safe standard of protection;
●● Develop a robust business case to deliver the scheme;
●● Obtain the necessary licenses, consents and approvals to deliver and
manage the scheme;
●● Provide a clear action and implementation plan for scheme delivery.
2
INTRODUCTION
2.1 Background to the Scoping Study
In accordance with Defra and the Environment Agency’s guidance on
coastal and flood risk management, the Eastern Solent Coastal Partnership
completed a Strategy Appraisal Report (StAR) in 2011. The StAR identifies
that the City is at significant risk of flooding with 4,211 residecCLntial, 364
commercial and 48 Ministry of Defence (MoD) properties currently at risk
from a 0.5% annual exceedance probability of flooding (AEP) due to
breaching of the existing coastal defences.
The StAR described the proposals for a 100 year flood and coastal erosion
risk management strategy for Portsea Island, Portsmouth, Hampshire. In
2012, the Eastern Solent Coastal Partnership, in collaboration with the
Environment Agency, gained formal approval to proceed with the Project
Appraisal Report (PAR) development for Cells 1 and 4 of the StAR
(Southsea and North Portsea Island respectively).
The coverage of Flood Cells 1 and 4 is shown in Figure 2.1 and can be
described as follows:
●● Flood Cell 1: Southsea (Portsmouth Harbour Railway Station to the
Royal Marine Museum);
●● Flood Cell 4: North Portsea Island (The Mountbatten Centre to, and
including, Milton Common).
In addition, the eastern part of the southern frontage is included within the
study area to inform potential future beach management activities.
2.2 Purpose of the Scoping Study
Due to the importance of reducing flood risk to the City and due to the
complexity of developing a robust scheme, that maximises benefits and
funding opportunities, the Eastern Solent Coastal Partnership has scoped
the work required to deliver the Southsea and North Portsea Island
Coastal Flood and Erosion Risk Management Schemes (the Schemes).
This Scoping Stage guides all subsequent work towards the realisation of
the Schemes, and is focused toward the next stage; the development of
the PARs.
The purpose of the Scoping study is, therefore, to:
●● Document the role and requirements of the PAR Stage to inform any
future schemes’ technical content and future approval processes such as;
○○ PAR for Large Project Review Group (LPRG) approval;
○○ Planning Permissions and other approvals for the Schemes by the
Local Planning Authority (LPA) and other statutory regulators and/or
consultees;
Figure 2.1: Flood Cell
1: Southsea (shown in
Red) and Flood Cell 4:
North Portsea (shown
in Yellow). The blue
zone is included to
inform potential future
beach management
activities.
© Crown Copyright. All first rights reserved. Licence No. LA 1000019217 2013
○○ Preparation, completion and submission of an Environmental Impact
Assessment (EIA) for any Schemes to support any approval processes.
●● Understand and identify the suitability and limitations of the existing
Portsea Island Coastal Strategy Study (2002-2012) (PICSS);
●● Identify the data requirements to support any scheme approval, design
and construction process, including the sourcing of existing data and
the identification, commissioning and collation of additional data;
●● Identify a robust and resilient approach for managing data through the
Scoping Stage and future scheme stages;
●● Identify an engaging and proactive approach to communication within
the project team, Council Members and influential internal and external
stakeholders;
●● Identify, share, allocate and cost project risks for managing and
monitoring throughout the project;
●● Generate a Project Implementation Plan;
●● Produce a methodology for undertaking the PAR, and summarise this
methodology in an Overview and Urgency Report.
2.3 Format of the Scoping Study
The Scoping Study comprises an Overview and Urgency Report and a
number of individual assessments, which explore the requirement for
delivering the PAR to achieve the necessary consents and funding to
deliver an appropriate flood and coastal risk management scheme. These
individual assessments are contained in the 14 Technical Reports noted in
Figure 2.2 below, with key aspects highlighted further in Technical Report
1: Overview and Urgency.
Figure 2.2: Format of
the Scoping Study
Scoping stage
Sets the requirements and process for preparing a
successful business case to deliver the schemes
Current Strategies, Plans and Data
Key deliverables of the Scoping Stage
North Solent Shoreline Management Plan
1. Overview and Urgency Report
2. Flood Risk Modelling
3. Economics
4. Contributions
5. Contaminated Land
6. Surveys
7. Asset Condition
8. Data Management
9. Risk and Programme Management
10.Communications Plan
11.Environmental
12.Archeology, Heritage and Monuments
13.Landscape Character Report
14.Beach Management Plan Scope
Portsea Island Coastal Strategy Study
Portsmouth Strategic Flood Risk Assessment
Portsea Island Surface Water Management
Shaping the Future of Portsmouth
Portsmouth Seafront Masterplan
++ extensive existing studies and data, held
both internally and externally
Project Delivery
Project Appraisal Report
Including:
Business Case
Funding
Licenses & Consents
Approvals
Detailed design
Construction
Operation and Maintenance
3
OBJECTIVE AND FORMAT OF THE TECHNICAL
REPORT
3.1 Technical Report Objective
This report has been prepared by Royal Haskoning for the sole benefit of
the Eastern Solent Coastal Defence Partnership on behalf of Portsmouth
City Council (PCC) (the Client). The objectives of the report are to identify,
as far as is reasonably possible, any potential sources of land
contamination within or in the vicinity of the study area in question at the
time of the study, which could impact works associated with the Schemes.
Contaminated Land assessments assist in understanding both how a
development will be affected by land contamination (e.g. additional costs
to ensure development site users do not come into contact with harmful
levels of contaminants) and how a development may affect land
contamination on or around the site (e.g. whether it will introduce new
pathways for contaminant migration to other sites or sensitive receptors).
In this case, the assessment is intended to assist in understanding issues
such as:
●● Where land contamination exists in an area which may need to be
protected by flood defences to prevent pollution of the environment;
●● Where contamination is present which may place constraints on
changes of land use (e.g. if the Schemes, once the design is further
developed, include giving public access to land which was previously
not accessible);
●● Where contamination is present which may increase the costs of the
Schemes (e.g. through the need for disposal of contaminated soils
during construction).
It is intended that this assessment should provide the starting point of a
process and that the relevance of land contamination issues to the
Schemes should be further assessed in conjunction with the development
of the Schemes’ engineering options and design. The steps of this
process are likely to include:
●● Refining of the conceptual model – with further design detail for the
Schemes and narrowing of the study area, refinement of desk based
assessment can be undertaken to look at specific pollutant linkages at
these locations to allow targeting (and therefore cost reduction) of any
site investigation required.
●● Intrusive site investigation – where the conceptual model identifies
potential contaminant risks from pollutant linkages either in relation
to specific work in specific locations associated with the Schemes or
within areas identified as at risk (e.g. from erosion), site investigation
is likely to be required to allow quantification of actual contaminant
concentrations.
●● Quantitative Risk Assessment – following intrusive site investigation
and laboratory analysis of soil and water samples, evaluation of
contaminant concentrations involves risk assessment of the identified
pollutant linkages to establish whether there are any unacceptable risks
to human health or controlled waters in any part of the Schemes’ area.
●● Remediation – should unacceptable risks be identified, it may be
necessary to implement a remediation process in order to reduce
these risks to acceptable levels. The remediation process involves
an appraisal of appropriate remediation options, development of
a remediation strategy, implementation of the chosen option and
verification after completion that the remediation has been successful.
Remediation options include altering the scheme design which can be
a highly cost-effective approach to risk reduction.
●● Materials Management – In relation to the potential construction
methodology of the Schemes, results from the site investigation and
risk assessment should be used to control potential movements
of excavated soil. As a waste, excavated soil requires a suitability
assessment before it can be re-used within a development scheme for
instance as landscaping or flood prevention bunds. Using the results of
the site investigation and undertaking ‘suitability for use’ assessments
for waste soils is intended to ensure maximum use is made of soils
which are safe to reuse on site and to minimise the need to import
additional clean soil to site, benefiting both sustainability and cost
efficiencies.
3.1.1 Context of this Assessment
This report has been produced as part of a wider assessment for the
Schemes, to identify any potential constraints with respect to any land
contamination issues which may impact the Schemes. Figure 1 in Annex
2 illustrates the process required for best practice to investigate, assess
and manage land contamination. This report provides the initial Preliminary
Risk Assessment and shows the iterative approach employed whereby, if
risks are identified, further collection and assessment of data is required.
This may be through further gathering of desk based information or by
intrusive site investigation and recovery of soil, water and gas samples (as
appropriate). Within this report, desk based data sources and information
from a site walkover have been assessed to build a source-pathway-receptor
pollutant linkage model (conceptual site model) for the three Flood Cells.
This report has been prepared with all reasonable skill and care, within the
terms of the contract with the Client. The conclusions in this report are
professional opinions, based on interpretation of environmental and historical
information identified in this report. This report should be read in conjunction
with the limitations provided in Annex 1 of this report. Geotechnical risks
and risks from unexploded ordnance are excluded from this assessment
and are discussed in Technical Report 6: Surveys.
3.2 Technical Report Format
The remainder of the report comprises the following principal sections:
●● Section 4 Approach – presents the agreed potential Scheme
parameters to be considered at Scoping Stage in the context of this
Technical Report, the partnership approach to working and links to the
wider Technical Reports prepared as part of this Scoping Study;
●● Section 5 Review of existing data – outlines the data available from the
PICSS and data obtained for this Technical Report;
●● Section 6 Site Location and Land Use – presents observations made
during the site walkover and potentially contaminative land uses
identified from historical maps;
●● Section 7 Environmental Setting – summarises current site conditions
including geology, hydrogeology, hydrology and nearby environmentally
sensitive land uses;
●● Section 8 Authorisations, Consents and Licences from Regulatory
Authorities presents a review of additional information on potentially
contaminative land uses;
●● Section 9 Existing Contaminated Land Investigation Reports - provides
summarised information gathered from for selected sites in or near the
study area;
●● Section 10 Initial Conceptual Site model and Preliminary Risk
Assessment - uses the information in Sections 6 to 9 to construct a
conceptual site model (source-pathway-receptor pollutant linkage
model) and to assign qualitative risk levels for each Flood Cell;
●● Section 11 presents the conclusions and recommendations;
●● Section 12 provides a bibliography.
4
APPROACH
4.1 Scoping Stage Scheme Parameters
A long-term strategic approach to the management of the Portsea Island
coastline has been developed through the PICSS completed in April 2010
and approved by Defra in May 2012.
The Strategy identified flood and coastal risk management proposals for
the whole of Portsea Island (Flood Cells 1 to 7) over a 100 year horizon.
Based on the findings of the Strategy, proposals for Flood Cells 1 and 4
(the highest risk areas) are being progressed as a priority, within the first
10 years of the Strategy.
The Scoping Stage will form the basis for subsequent work towards the
realisation of the Schemes, which will go through a number of stages over
a period of several years. It is therefore crucial to undertake this stage of
work with an understanding of the desired outcomes of the Schemes and
also the approval, design and construction process that should be followed.
In order to prepare this Contaminated Land Technical Report, it is
important to define the parameters that future flood and coastal
management schemes for Flood Cells 1 and 4 may include.
The PICSS identified preferred options for Flood Cells 1 and 4 based on
considered analysis from a long list of options and these preferred options
are illustrated in Table 4.1.
Table 4.1: PICSS Preferred Options
Flood Cell
Strategy recommended
management approach
Strategy preferred scheme
options
1 Southsea
“Raise (improve) the current
Standard of Protection (SoP)
from 100% to 0.5% Annual
Exceedence Probability (AEP)
to protect properties in 100
years’ time”.
“Raising sea walls,
improving sea wall integrity
and establishing sustainable
methods of retaining beach
material”.
Sustain 0.5% AEP to keep
pace with sea level rise”.
“Raising sea wall and
embankment crest heights
and replacing some of the
existing structures with
enhanced defences”.
4 North Portsea Island
In addition, the Strategy confirmed the Shoreline Management Plan policy
for Portsea Island of ‘Hold the Line’, to protect the populated frontages
and to reduce the risk of contaminating the harbours from erosion of the
landfill sites.
The Outline Implementation Programme identified in the Strategy gives
some detail about the potential scheme works. The programme includes
detail on the lengths of defences to be improved or sustained and the
footprint of the scheme works.
However, while the Strategy clearly establishes preferred options and
develops a business case for central government funding based on
scheme costs and economic damage avoided from coastal flooding, it is
important to note that at this Scoping Stage, the Scheme development
needs to be progressed in a manner which does not preclude possible
changes to the Strategy proposals. Such changes may arise through
factors such as stakeholder engagement, changes in national policy and
guidance. A recent example of this is the change to the national Flood
Defence Grant in Aid (FDGiA) funding. Schemes are now expected to be
part funded via contributions, as set out by the Environment Agency’s
Flood and Coastal Resilience Partnership Funding Policy. This links well
with PCC’s aspirations for the Schemes to deliver broader outcomes,
wider benefits and increasing the opportunity for contributions through
appropriate stakeholder engagement.
It is recognised that an adaptive management approach to achieving an
improved standard of protection will be needed to maximise the alternative
funding opportunities. The project should not, therefore, constrain itself
simply to the Strategy preferred options and footprint.
Table 4.2: Potential
Scheme Works
(PICSS, 2012)
Flood Cell
On this basis we have therefore considered the following potential scheme
works and scheme footprint in the context of this Contaminated Land
Scoping Stage Technical Report, generally broadening the Schemes’
parameters and possible scheme construction area (footprint) which were
established through the Strategy (Table 4.2).
Strategy Management
approach
Strategy Scheme works
Scoping Stage potential
Scheme works
●● Raising existing walls
“Raise (improve) the
current SoP from 100%
1 Southsea to 0.5% AEP to protect
properties in 100 year
time”.
4 North
Portsea
“Sustain the current AEP
provided by the defences
to keep pace with sea level
rise”.
“Raising sea walls,
improving sea wall
integrity and establishing
sustainable methods of
retaining beach material”.
“Raising sea wall and
embankment crest heights
and replacing some of the
existing structures with
enhanced defences”.
●● Creating a new line of
defence (set back)
●● Active beach
management
●● Removal of certain
structures
●● Raising existing walls
●● Creating a new line of
defence (set back)
●● Removal of certain
structures
●● Tidal barrier
Scoping Stage potential
build/construction
approach
●● Steel Sheet Piling
●● Reinforced concrete
●● Mass concrete
●● Rock armour
●● Groynes
●● Gabion baskets
●● Earth embankments
●● Shingle management
●● Steel Sheet Piling
●● Reinforced concrete
●● Mass concrete
●● Rock armour
●● Groynes
●● Gabion baskets
●● Earth embankments
The potential future schemes footprint considered at this Scoping Stage
for this Technical Report was reduced in size from the overall Scoping
Stage study area as presented in Figure 4.1.
Figure 4.1: Potential
Schemes Footprint
at Scoping Stage
considered for
Contaminated Land
Technical Report.
4.2 Working in Partnership
This Technical Report has been produced as a partnership between Royal
Haskoning and the Eastern Solent Coastal Partnership, with key members
of the team as follows (Table 4.3):
Table 4.3: Team Members
Team member
Organisation
Alison Hallas (Author)
Royal Haskoning
Gavin Holder
Sarah Hayne
Portsmouth City Council Contaminated Land Team
Caroline Timlett
Bret Davies
Liz Williams
PCC Contaminated Land Team
4.3 Links to the Wider Scoping Stage
As part of the suite of stand-alone Technical Reports produced as part of
this Scoping Stage, the data collated and produced and the findings from
this Technical Report will contribute to the wider outputs from the Scoping
Stage.
This Technical Report, however, is particularly key in developing the
understanding of risks, opportunities and constraints to scheme option
development in terms of contaminated land.
The Scoping Stage Technical Reports that will, therefore, directly draw on
the findings presented in this Technical Report are presented in Table 4.4.
able 4.4: Wider Technical Reports with Direct Links to this Technical
T
Report
Technical Report
reference number
Technical Report title
1
Overview and Urgency
6
Surveys
9
Risk and Programme Management
11
Environment
5
REVIEW OF EXISTING DATA
5.1 PICSS Review
The Strategy considered potentially contaminated land within Portsea
Island, which included a contaminated land risk assessment report. It
specifically focused on the risks from landfills and areas of fill to
ecologically designated sites under the Habitats Regulations, 1994.
The following aspects have not been assessed:
●● Risks from sources of land or water contamination other than landfill or
areas of infill;
●● Risks to other sensitive receptors (including human health and
groundwater) from the development from contamination;
●● Risks to the development from contamination in terms of the quality of
material which may need to be moved within the Schemes or disposed
of off-site.
In addition, since the Contamination Risk Assessment Report (2004) was
completed, additional contamination events may have occurred and/or
additional land quality reports may have been completed.
5.2 Scoping Stage Data Collation and Review
The data presented in Table 5.1 was requested for this Technical Report,
with notes to record whether such data was made available to inform the
Technical Report and whether it may be available for any further related
studies.
Table 5.1: Data Request at Scoping Stage and Availability
Data
Source
Format
Procurement
route
Licensing
& IPR
Received
(date)
Future availability and
other comment
Environmental
Sensitivity Report
(Envirocheck® Report)
Landmark
Information
Group
pdf
Direct
purchase
Licenced
to PCC
March/April
2012
Available on Box
PCC Contaminated
Land Archive reports
PCC
Contaminated
Land Team
Via PCC
word/pdf Contaminated
Land Team
Archive
reports
are part of
the public
record
April/May
2012
10 reports received as
listed in Section 9.2 and
available on Box
6
SITE LOCATION AND LAND USE
6.1 Current Land Use
The site comprises three areas of the Portsea Island coastal frontage,
known as Flood Cells 1, 4 and part of 2 (Eastney area). The locations of
the Flood Cells are shown in Figure 2.1. In order to maximise the costeffectiveness of data purchases, the study area for the contaminated land
assessment has been restricted to areas considered likely to be within the
construction footprint of the Schemes and those areas where pollutant
linkages are likely to be directly affected by the construction works.
6.1.1 Flood Cell 1- Southsea
Flood Cell 1 comprises a stretch of coastal defences and land behind in
the urban south west of Portsea Island. Land use within the Cell includes
residential areas, light industrial and commercial uses and public open
space. Anecdotal evidence from PCC gathered during the site visit
indicates that raised embankments at Southsea Common are of unknown
fill and subject to wave overtopping; that land behind the embankments is
former MoD land and may be used to allow flood waters to drain away
(Plate 1); and that some parts of the Cell 1, including the Gunwharf Quays
area in the west, have been recently redeveloped.
Currently, the area known as the Great Morass is in mainly residential use
(Plate 2), although anecdotal evidence from PCC gathered during the site
visit indicates that site investigations in this area have encountered Made
Ground/rubble with high metal and Polycyclic Aromatic Hydrocarbon
(PAH) concentrations and peat deposits. Groundwater is reported to
collect in cellars in this area and pumping is sometimes required to drain
these. Combined sewers in the area are also reported to flood.
Plate 1: Embankments
and open space at
Southsea Common
Plate 2: Great Morass
Area
According to information provided by PCC, Canoe Lake is a site at which
site investigation for land contamination was undertaken (see Section
9.3). The water level in the lake is understood to be controlled via a
connection to a tidal sluice and it is understood to flood regularly, from
anecdotal information provided by PCC during the site walkover.
6.1.2 Flood Cell 2 – Fraser Battery/Eastney
Flood Cell 2 comprises open and derelict land in the south east with
residential estates (Plate 3) and a marina behind. Current coastal protection
along the shore of Lock Lake is restricted to rock armour (Plate 4).
Plate 3: Residential
Use in Flood Cell 2
Plate 4: Shoreline of
Lock Lake
Anecdotal evidence from the walkover suggests that there are extensive
former MoD landfills in this area and that industrial uses on the currently
derelict land included chemical testing and weathering of plastics.
6.1.3 Flood Cell 4 – North Portsea Island (described from south east
to north west)
The far south east of Flood Cell 4 comprises a former landfill at Milton
Common. This is currently used as public open space and vegetated with
rough grass, brambles/scrub vegetation and footpaths. A concrete structure
passes through the landfill (Plate 5) which is indicated to be a continuation
of the sea wall which currently protects the south of the landfill. The north
of the landfill is protected by rock armour (Plate 6). At the time of the site
walkover there was visual evidence that leachate may be permeating the
sea wall (Plate 7).
Great Salterns Quay lies to the north of Milton Common and comprises a
short quay structure fully covered with concrete. Immediately behind this
is the A2030 Eastney Road and, behind this, open land and a golf course.
The coastal defences along this stretch of the Flood Cell comprise a
concrete wall.
Anecdotal information suggests that the north east corner of Flood Cell 4
includes a former airfield. This area currently incorporates residential and
commercial/industrial uses. Along the north of Flood Cell 4, Ports Creek is
bordered by a concrete wall and earth embankment (Plate 8) with a
bastion structure and open land behind.
Plate 5: Concrete
wall structure passing
through Milton Common
Plate 6: Rock armour
protecting north of
Milton Common (in
distance)
6.2 Former Land Use (Historical Map Review)
Historical maps from 1878 to 2011 were obtained from Landmark Information
Group as part of an Envirocheck® Report, copies of which are included in
Annex 3. In this initial desk based study of land quality constraints, only
the 1:10,000 scale maps have been reviewed. Once engineering options
have been developed further, assessment of relevant 1:2,500 and 1:1,250
may be required to provide additional detail on the historic land uses.
These have been provided as part of the Envirocheck® reports for the
Plate 7: Evidence of
seepage through Milton
Common sea wall
Plate 8: Wall and
embankment at Ports
Creek
flood cells. PCC Contaminated Land team should be consulted to
establish if such a review has already been undertaken.
The distances provided within this section are in relation to the approximate
site boundary, shown on Figure 4.1. Potentially contaminative land uses
are summarised in Tables 6.1 to 6.3 with those considered to pose a
potentially significant risk to the Schemes in terms of land or water quality
highlighted in bold. They are shown on Figure 2 of Annex 2. These
potential sources, together with the environmental setting information in
Section 7 and information on consents and licences in Section 8 have
been considered in constructing the Conceptual Site Model in Section 10.
The Conceptual Site Model, and the Preliminary Risk Assessment, focus
on potential sources, pathways and receptors which may pose a
potentially significant risk to the Schemes.
6.2.1 Flood Cell 1 -Southsea
Table 6.1: Potentially Contaminative Land Uses based on Historical Maps: Flood Cell 1
Envirocheck Map
Feature
Slice Ref
Ref1
Approximate
distance/
direction
from Site
First
shown
Last
shown
Comments2
C
1
Wharves – Gunwharf
Quays Area5
On-site
1870
2000
In N of flood Cell. Majority of wharf buildings no
longer shown by 2000. Wharves redeveloped
by 2006.
C
2
Basin
Partially
on-site
1870
1938
Basin crosses the NE site boundary. Indicated
now to be partially infilled.
C
3
Royal Dockyard4
200m N/NE
1870
20113
Dockyards already well developed to the north
including jetties, basins, timber pond, timber
yards etc.
C
4
Railway Line
Partially
on-site
1870
20113
Railway lines and sidings serving the Royal
Dockyard, Portsmouth Harbour station and the
wharf buildings on-site.
C
5
Works
150m to E
1962
1978
On Gunwharf Road. Circular structures (tanks?)
shown on 1978 map.
A
6
Point Battery
On-site
1931
20114
On coastal frontage in W of Flood Cell.
A
7
West Battery and
Embankments
On-site
1931
20114
In area of Southsea Castle.
A
8
King’s Bastion
Embankments
On-site
1931
20113
-
A
9
Depot
On-site
1991
20114
North of the West Battery.
A
10
Infirmary
50m to N
1931
1938
To S of Clarence Barracks. Last labelled as
infirmary in 1938 although buildings remained
on site on later maps.
B
11
Canoe Lake
On-site
1870
20113
Outline of lake changes between 1870 and
1898 indicating possible infilling.
B
12
Lumps Fort
Embankments
On-site
1931
20114
To E of Canoe Lake. Already marked as
dismantled in 1931.
B
13
Highland Road
Cemetery
350m to N
1898
20114
(See also Flood Cell 2.)
B
14
Railway – Southsea
Branch
200m N
1898
1938
Redeveloped by 1972.
B
15
Old Gravel Pit
Adjacent to N
flood cell
boundary
1898
1998
To W of Canoe Lake. Indicated to be infilled by
1911; redeveloped by 1931.
B
16
Eastney Fort
Embankments
250m to E
1932
20114
1.
2.
3.
4.
5.
Map reference relates to Figure 2 of Annex 2
Comments have been made in the Table only where the historical maps or photographs supplied additional information.
Still present at time of site walkover
Possibly still present
The wharf buildings and Naval Base are not shown in detail on the 1898 or 1911 historical maps, but the outline of their coastal
frontages is unchanged. It is assumed that the detail was removed from these maps for security reasons
Envirocheck Map
Feature
Slice Ref
Ref1
Approximate
distance/
direction
from Site
First
shown
Last
shown
Comments2
A
17
Glory Hole Landfill
On-site near
NW flood cell
boundary
1871
1911
Shown as mud on historical maps.
A
18
Gravel Pit
On-site
1871
1911
S of Glory Hole. Redeveloped by 1932.
A
19
Brickfields/Gravel pits
350m NW
of flood cell
boundary
1871
1898
Gravel Pit shown on brickfield site in 1898;
redeveloped by 1911.
A
20
Old Canal
400m to N
1872
1911
Embankments shown to either side of canal.
Partially infilled by 1911.
A
21
Rifle Ranges
On-site
1898
1972
Crossing the Flood Cell NE - SW to the SE
of the Glory Hole and SE to NW to S of Glory
Hole. Targets labelled close to the shoreline.
Disused by 1972. Mainly redeveloped by 2000.
A
22
Sewage Pumping
Station
Adjacent to
site boundary
to W
1898
20113
Shown as Sewage Pumping station and Refuse
Destructor, and tramway shown linking site to
Eastney Lake shore in 1932.
A
23
Eastney Barracks and
Hospital
50m to NW
1898
1972
A
13
Highland Road
Cemetery
450m to NW
1898
20114
-
A
24
Possible Refuse/Slag
Heap
On-site
1911
1911
Adjacent to NW site boundary. Developed into
caravan site by 1962.
A
25
Isolation Hospital
450m to N
1911
1962
Later Langstone Hospital/Sanatorium.
A
26
Possible Refuse/Slag
Heap
200m NW
1911
1911
Part of Eastney Recreation Ground by 1932.
A
27
Royal Marines
Infirmary
On-site
1911
1972
In W of Flood Cell. Redeveloped by 2000.
A
16
Embankments
Partially
within site
1932
20113
Embankments along southern boundary of
Eastney Barracks. Partially removed by 1962.
B
28
Old Battery
On-site
1871
1871
In east of site on spit.
B
29
Old Gravel Pit
On-site
1898
1911
In east of site on spit; redeveloped by 1972.
B
30
Sewage Outfalls
On eastern
site boundary
1911
20114
-
B
31
Embankments
On-site
1932
20114
Associated with Fort Cumberland in east of
flood cell.
B
32
Sewage Tanks
On-site
1932
1962
Associated with Fort Cumberland in east of
flood cell. Northernmost sewage tanks replaced
by sewage works by 1972.
1.
2.
3.
4.
Comments have been made in the Table only where the historical maps or photographs supplied additional information
6.2.3 Flood Cell 4 – North Portsea Island
Envirocheck Map
Feature
Slice Ref
Ref1
Approximate
distance/
direction
from Site
First
shown
Last
shown
A
33
Sand Pit
150m S
1871
1871
A
34
Sanatorium
400m to SW
1898
20114
A
35
Gravel Pit
350m to SW
1898
1910
A
36
Sand Pit
325m to SW
1898
1910
A
37
Possible Gravel Pit
Adjacent to
S Flood Cell
Boundary
1910
1910
A
25
Isolation Hospital
200m to S
1911
1962
A
38
Sewage Lifting
Station/Pumping
Station
400m to NW
1910
20114
Last labelled as pumping station in 2000;
buildings still indicated to be present.
Comments2
Later St James Hospital.
A
39
Isolation Hospital
300m to W
1910
2006
Later Infectious Diseases Hospital and St
Mary’s General Hospital. South of hospital site
redeveloped as a school by 2006. Remainder
redeveloped by 2011.
A
40
Milton cemetery
100m to SW
1932
20114
-
A
41
Bafffins Refuse
Destructor/Works
150m to NW
1932
1963
Labelled ‘works’ in 1963.
A
42
Works
350m to NW
1963
1963
-
A
43
Central Depot
Adjacent to
SW Flood
1963
Cell Boundary
2000
A
44
Milton Common
On-site
1972
20113
Indicated to be mainly infilled and protected by
a sea wall.
A
45
Great Salterns Quay
On-site
1973
20113
Quay structure shown.
C
46
Railway
Partially onsite
1870
20113
Railway line crosses Flood Cell in NE
C
47
Coastal
Embankments
On-site
1870
20113
Embankments indicated to be present for large
stretches of the coastal frontage.
C
48
Rifle Range
On-site
1898
1932
In NE of Flood Cell.
C
49
Hilsea Gas Works(5)
850m to W
1910
2006
Gasholders still shown as present in 2006;
removed by 2011.
C
50
Embankments of
Hilsea Lines and
Bastions
Partially onsite
1910
20114
-
D
51
Pumping Station
200m to N
of Flood Cell
Boundary
1932
1938
On N side of Ports Creek.
Envirocheck Map
Feature
Slice Ref
Ref1
Approximate
distance/
direction
from Site
First
shown
Last
shown
Comments2
C
52
Works
200m to N
of Flood Cell
Boundary
1973
20114
On N side of Ports Creek .
D
53
Works
500m to NW
of Flood Cell
Boundary
1978
20114
On N side of Ports Creek Outline of buildings
present in 2006.
C
54
Aerodrome &
Associated Industrial
Estate
Adjacent to
W Flood Cell
Boundary
1942
1983
Latter labelled Portsmouth City Airport. Works,
stores, factories and tanks shown on this site
from 1963. Aerodrome last shown on 1983
(Russian) map. Site later developed into Bilton
Business Park.
C
55
Hilsea Lines Depot/
Industrial Park
Adjacent to
S Flood Cell
Boundary
1932
20114
Timber yard and tanks shown from 1973.
C
56
Factory
300m to S
1963
20114
Later marked as Broad Oak Works and Browns
Lane Works.
C
57
Works
100m to S
1963
20114
-
1973
20114
To N of Ports Creek. Shown as Industrial Estate
by 2000.
1990
20114
At Kendalls Wharf.
C
58
Works
250m to N
of Flood Cell
Boundary
C
59
Works
On-site
B
60
Stamshaw Brick
Works / Shamshaw
Chemical Works
Adjacent to
W Flood Cell
Boundary
1870
20114
Labelled as Brick Works in 1970. Shown as
Chemical Works in 1898. Tanks shown on-site
from 1932. Works buildings removed by 1962
and replaced by Coal Depot by 1973. Buildings
subsequently marked as ‘Depot’.
B
61
Brick Works
200m to S
1870
1870
-
B
62
Alexandra Park Area
On-site
1898
20114
Outline of seafront altered, indicating possible
infilling in area later labelled Alexandra Park.
B
63
Laundry
450m to S
1898
1898
On Gladys Avenue.
B
64
Hospital
400m to E
1911
1973
At Hilsea Artillery Barracks; redeveloped by
1990.
B
65
Tank
250m to S
1962
1962
At TA centre on Military Road.
B
66
Depot
100m to W
1962
2011
North of Stamshaw Chemical Works.
B
67
Works
450m to S
1963
1990
In Hilsea area on Copnor Road. Redeveloped
by 2000 – new development not labelled.
B
68
Motorway
Adjacent to
N Flood Cell
Boundary
1973
20113
North side of Ports Creek rebuilt to construct
motorway.
1.
2.
3.
4.
5.
4
Comments have been made in the Table only where the historical maps or photographs supplied additional information
Potentially significant source of contamination identified greater than 500m from the Flood Cell boundary
7
ENVIRONMENTAL SETTING
7.1 Published Geology
To obtain information about the geology of the area, reference has been
made to the British Geological Survey (BGS) Maps of Portsmouth (Sheet
331) and Fareham (Sheet 316) in the 1:50,000 series (Solid and Drift
Edition). In this initial desk based study of land quality constraints, BGS
borehole logs have not been assessed. Once engineering options have
been developed further, logs may be required to provide additional detail
on the geology which is likely to be encountered during excavations or
which may affect the Schemes. Information from BGS logs and local
thicknesses of strata has been summarised in Technical Report 6: Surveys.
The three Flood Cells are indicated to be underlain by a variety of
superficial and bedrock geologies. These are described below and an
extract from the geological maps is shown in Figure 3 of Annex 2.
7.1.1 Flood Cell 1 - Southsea
The majority of Cell 1 is shown as underlain by Storm Gravel Beach
deposits underlain by the Bracklesham Group Formations (Earnley Sand
and Marsh Farm Formation underlain by the Wittering Formation). In the
north of the Flood Cell the bedrock changes to the Wittering Formation,
which is generally overlain by Second River Terrace Gravels. In the far
west of the Flood Cell, a large deposit of Made Ground is shown to overlie
the natural strata. Towards the centre, north of the site, localised
superficial deposits of Marine and Estuarine Alluvium and Peat are shown
to overlie the Second River Terrace deposits. The area of the Great
Morass is clearly visible on the geological map as an area overlain by
alluvium, with overlying discrete peat deposits.
Towards the east of the Flood Cell, the River Terrace Gravels are overlain
by River Terrace and Aolian Deposits (‘Brickearth’) which is described as
mainly loam and clay. A second small deposit of Made Ground is shown to
overlie the Brickearth and Storm Gravel Beach Deposits in this area.
The Bracklesham Group is underlain by the Thames Group (London Clay
Formation), which overlies the Lambeth Group (Reading Formation) and
the Upper Chalk.
Almost the entire area of Flood Cell 2 is indicated to be underlain by
Storm Gravel Beach deposits over the Bracklesham Group (Formations
not specified). In the north and north east of the Flood Cell, deposits of
Made Ground are present and, at the western boundary of the Flood Cell,
Second River Terrace Gravels are indicated to overly the Bracklesham
Group bedrock.
Flood Cell 4 extends north along the eastern coast of Portsea Island
through several changes of bedrock geology. At its southernmost point
(underlying the Milton Common area) the bedrock is indicated to be
London Clay, overlain by Marine and Estuarine Alluvium or Marine Beach
and Tidal Flat Deposits. A large deposit of Made Ground is shown in this
area corresponding to known areas of landfilling (see Section 8).
Immediately to the north of Milton Common, the superficial Marine and
Estuarine deposits are shown to be underlain by Bognor Sand of the
London Clay Formation, with London Clay beneath and, to the north of
this, in the Great Salterns Quay area, the superficial deposits are again
directly underlain by London Clay. Immediately to the west of these areas,
significant deposits of Made Ground are shown, again corresponding to
known areas of landfilling (see Section 8). North of Salterns Quay, the
superficial deposits are underlain by the Reading Formation.
In the north east of Flood Cell 4 a significant deposit of Made Ground
does shown, overlying bedrock geology comprise the Upper Chalk. It is
not clear whether there is an intervening stratum of Marine and Estuarine
Alluvium.
In the north of Flood Cell 4 and in the north west, the Upper Chalk is
indicated to be overlain by Marine and Estuarine Alluvial deposits adjacent
to Ports Creek, and by Brickearth in the central northern part of Portsea
Island.
7.1.4 Geological Descriptions
Table 7.1 presents a generalised summary of nature of the geological
strata in Sections 7.1.1 to 7.1.3. The descriptions were obtained from the
BGS Lexicon of Rock Units web site (http://www.bgs.ac.uk/Lexicon/) and
Geology of the Fareham and Portsmouth District, BGS, 2000.
Table 7.1: Generalised Summary Descriptions of Geological Strata
Group
Quaternary
Superficial
Deposits
Stratum
Bedrock Geology
Aeolian (Brickearth) Deposits
Yellow/brown mainly non-calcareous
silt or clayey silt which may locally
contain a few flint and chalk fragments
Alluvium
Soft organic mottled silty and sandy
clay
Second River Terrace Gravels
Gravels and sandy gravels (only the
higher terraces are described as
clayey). In the south of the Portsmouth
district, the gravels are predominately
flint
Estuarine Alluvium
Brown and grey mottled soft silty clay
and silt
Storm Gravel Beach Deposits
Fine to medium gravels with some
interstitial sand and shell debris
Group
Stratum
Bedrock Geology
Earnley Sand Formation
Glauconitic silty sands and sandy silts,
with thickness given as 22-25m. The
Earnley Sand rests on the Wittering
Formation, with the base of the
Formation marked by the transgressive
surface (a boundary formed by rapid
sea level rise) overlain by glauconitic
silty sands and pebble bed
The Earnley Sand is overlain by the
Marsh Farm Formation. The boundary
is marked by the upward change from
the Glauconitic Sands of the Earnley
Sand Formation to the thin-bedded
clays and silts with Glauconitic Sand
laminae of the Marsh Farm Formation
Bracklesham
Group
Marsh Farm Formation
Wittering Formation
Laminated clay; sand interbedded with
clay in equal proportions; and fine- to
medium-grained sparsely Glauconitic
Sand with laminae and intercalations
of clay, with a thickness of 12 – 13.5m.
As noted above, the formation rests on
the Earnley Sand. It is overlain by the
Selsey Sand Formation whose base is
marked by a sharply change to thinly
bedded clays and silts with glauconitic
sand laminae.
Greyish brown laminated clay;
sand interbedded with clay in equal
proportions; and fine- to mediumgrained sparsely Glauconitic Sand.
It rests on London Clay, a dark grey
bioturbated clay and its thickness is
given as 40-53m.
The Wittering formation is overlain
by Earnley Sand Formation, with the
boundary marked by the transgressive
basal surface of Glauconitic silty sands
with pebbles
Thames
Group
London Clay Formation
Grey, pyritic, bioturbaded silty and
fine-grained sandy clay with seams
of calcareous cementstone and flint
pebble beds. It has a sandy bed at the
base
Bognor Sand
5-10m thick and comprising Glauconitic
bioturbated or cross-bedded fineand medium-grained sands, partially
cemented
Upper Chalk
White chalk with flint seams
Chalk Group
7.2 Coal Mining Affected Areas and Ground Stability
No coal-bearing formations have been identified underlying the site.
Hazards relating to ground stability have not been considered as they are
outside the scope of this report. These are considered as part of the
geotechnical assessment for the Schemes. The Schemes, as currently
developed, will undergo geotechnical risk assessment with particular
reference to ground stability.
7.3 Hydrogeology and Groundwater Vulnerability
The site is not indicated to lie within a groundwater Source Protection
Zone. It is, however, shown as being partially underlain by a Secondary
Aquifer (Class A) which is interpreted as relating to the Brickearth Second
River Terrace Gravels and Storm Gravel Beach Deposits. The remainder
(mainly eastern, northern and western coastal areas) are underlain by a
Secondary Undifferentiated Aquifer, which corresponds to the Marine and
Estuarine Alluvium.
In terms of the bedrock geology, the southern part of Portsea Island is
underlain by a further Secondary Aquifer (Class A), corresponding to the
Bracklesham Group, Whitecliff Sand and Portsmouth Sand (see Annex 3).
The central part of Portsea Island is mainly underlain by unproductive
strata (London Clay), although the Bognor Sand is also classed as a
Secondary Aquifer (Class A). In the north of the Island, the Reading
Formation is a Secondary Aquifer (Class A) and the Upper Chalk is
classed as a Principal Aquifer.
A summary of the status of the aquifers underlying each Flood Cell is
provided in Table 7.2 and on Figure 4 of Annex 2. The aquifer
classification definitions provided by the Environment Agency are provided
in Table 7.3.
Table 7.2: Generalised Summary of Aquifers Underlying the Flood Cells
Flood Cell Superficial Geology
1
2
4
Mainly Secondary A
Some unproductive strata
Secondary A
Mainly unproductive strata
Secondary A in northern central area
Bedrock Geology
Secondary A
Secondary A
Unproductive Strata (south east)
Secondary A (east/west)
Principal (north)
Table 7.3: Generalised Summary of Aquifers Underlying the Flood Cells
Aquifer Classification
Bedrock Geology
Principal Aquifer
Strata that have high inter-granular and/or fracture
permeability - meaning they usually provide a high level of
water storage. They may support water supply and/or river
base flow on a strategic scale
Secondary A Aquifer
Permeable layers capable of supporting water supplies at a
local rather than strategic scale, and in some cases forming
an important source of base flow to rivers
Secondary
Undifferentiated Aquifer
A stratum which has previously been designated as both
minor and non-aquifer in different locations due to the
variable characteristics of the rock type
Non-productive Strata
Strata with low permeability that have negligible significance
for water supply or river base flow.
According to Environment Agency information on groundwater vulnerability
(see Annex 3) soils overlying Portsea Island are likely to be of high
permeability, with limited capacity to attenuate pollutants. Groundwater
vulnerability is, therefore designated as high. No groundwater abstractions
were identified within the study area. No licensed groundwater abstractions
were identified; however private water abstractions may be present within
or close to the study area.
The Environment Agency website1 indicates that the Water Framework
Directive (WFD) status of groundwater chemical quality beneath the majority
of Portsea Island is ‘good’ (relating to water quality within the Bracklesham
Group). In the north of the island, where the superficial geology is underlain
by the Upper Chalk Group, the WFD status is shown as ‘poor’ relating to
the quality of water within the Chalk (due to abstraction and water quality
pressures).
7.4 Hydrology
Table 7.4 and Figure 5 in Annex 2 shows the main surface water features
identified in the vicinity of the site.
able 7.4: Surface Water Features identified within 500m of the Site
T
Boundary
Flood Cell Feature
Distance and Direction
Canoe Lake
On-site
1
King’s Bastion Moat
On-site
Portsmouth Harbour and the Solent
Adjacent to S and W
2
Chichester and Langstone Harbours and the Solent Adjacent to N, E and S
4
Ponds on Milton Common (Frog Lake, Duck
Lake and Swan Lake)
On-site
Great Saltern’s Lake
Adjacent to W (fed by
drain flowing south east
through Great Salterns
Golf Course)
Ponds on Great Saltern’s Golf Course
200m-350m to W
Baffins Pond
125m to W
Ports Creek
Adjacent to N
Hilsea Lines Bastion Moat
Adjacent to S
Chichester and Langstone Harbours
Adjacent to E
Portsmouth Harbour
Adjacent to W
There are eight transitional and coastal water bodies in the wider Portsmouth
River Basin District (PRBD) whose catchments fall within the study area1.
The current status, objectives, mitigation and risks to these water bodies are
detailed in Table 6.1 in Technical Report 11: Environmental. The objective
for all these water bodies is for Good Ecological Potential by 2027, with 4
having a target of Good Chemical Status by 2015 or 2027, of which 3 already
achieve this target but one (C4 - Solent) is currently failing. The key risk or
constraint is to ensure that any scheme preserves and where possible enhances
ecological value of marginal aquatic habitat, banks and riparian zone.
A summary of surface water abstractions licensed by the Environment
Agency is provided in Table 7.5.
Table 7.5: Generalised Summary of Surface Water Abstractions
Flood
Cell
1. http://maps.environmentagency.gov.uk/wiyby/
accessed on 22nd March
2012.
On-site abstractions
Abstractions within 500m of Flood
Cell boundary
1
Two abstractions from tidal waters
located at Gunwharf Quays for
‘lake and pond throughflow)
None
None
2
One abstraction from tidal waters
located at Hayling Island Ferry
Pontoon for fish farm/cress pond
throughflow
None
Three abstractions at 480-490m from
the Flood Cell boundary (tidal water).
All are for spray irrigation at North
Harbour, Cosham
4
7.5 Flood Risk
Flood risk within the Flood Cells is assessed within the PICSS and is not
considered further within this assessment.
7.6 Environmentally Sensitive Land Uses
The whole of Portsea Island lies within a Nitrate Vulnerable Zone. The
Schemes are not expected to be impacted by this designation2.
7.6.1 Flood Cell 1 - Southsea
The boundary of the Portsmouth Harbour Site of Special Scientific Interest
lies 430m to the north west and south west. This is discussed further in
Technical Report 11: Environmental.
To the north east and east, the Flood Cell borders a Ramsar Site/Special
Protection Area (Chichester and Langstone Harbours) and a Site of Special
Scientific Interest (Langstone Harbour). To the north east, east and south
east, the site borders a Special Area of Conservation (Solent Maritime SAC).
Approximately 340m to the east lies the Sinah Common Local Nature
Reserve. This is discussed further in Technical Report 11: Environmental.
The Chichester and Langstone Harbours Ramsar Site and Special Protection
Areas, Langstone Harbour Site of Special Scientific Interest and the Solent
Maritime Special Area of Conservation lie adjacent to Flood Cell 4 to the
east. Langstone Harbour is also designated as a Local Nature Reserve
and Local Wildlife Trust Reserve.
Portsmouth Harbour Ramsar Site, Site of Special Scientific Interest and
Special Protection Area lie adjacent to the Flood Cell to the west. The
Portsmouth Harbour Site of Special Scientific Interest also extends to the
north, along Ports Creek. This is discussed further in Technical Report 11:
Environmental.
7.7 Radon Gas
The Envirocheck® report states that some areas of the Flood Cells are within
radon affected areas but that radon protective measures are unlikely to be
required for dwellings and extensions within the Flood Cell areas. However,
the Health Protection Agency has recently indicated that radon risk may
not be restricted to the defined ‘radon affected areas’3. Should any
confined spaces be proposed as part of the Schemes, risks from radon
should be further considered.
2. Nitrate Vulnerable Zones
are areas in which water
quality has been impacted
by concentrations of nitrate.
The largest contributor to
nitrate pollution is farming,
mainly by application of
nitrogen-rich fertilisers,
and hence controls within
Nitrate Vulnerable Zones
focus on farming practices.
Given that the Flood Cells
are not predominantly in
agricultural use, it is
considered unlikely that
the Schemes will have a
significant impact on
nitrate pollution in water
receptors.
3. Radon and Public Health:
Report of the
independent Advisory
Group on Ionising Radiation,
Health Protection Agency,
June 2009
7.8 Underground Utilities
An underground utilities assessment is beyond the scope of this report at
this scoping stage; however, data have been collected and are reported in
Technical Report 6: Surveys. Underground service conduits can act as
preferential pathways for contaminant migration and some underground
services (e.g. drinking water supply pipes) can be at risk of impact from
contamination. Potential pathways should be assessed further once the
Schemes design is known in more detail.
8
AUTHORISATIONS, CONSENTS & LICENCES
FROM REGULATORY AUTHORITIES
A search was carried out of Environment Agency and Local Authority
records for potentially polluting processes, discharge consents, landfill
sites, water abstraction points and other potential sources of pollution that
have been registered and are present on public registers within 500m of
the site. The results are summarised in Tables 8.1 to 8.3. These searches
provide additional indications (to those identified from the historical map
review and site walkover) of potentially contaminated areas within or close
to the study area.
The information referred to herein is contained within the appended
Envirocheck® report (Annex 3) produced by Landmark Information Group.
In this section, all distances are approximate and are in relation to the site
boundary as shown in Figure 4.1. Where an authorisation type is not listed
in the table, the Envirocheck® report indicates that no such records exist
within 500m of the site. Entries which are considered to be associated
with a potentially significant risk to the Schemes in terms of land or water
quality are shown on Figure 2 of Annex 2 and assessed in Section 9.
8.1 Flood Cell 1 – Southsea
Table 8.1: Summary of Records for Potentially Polluting Processes: Flood Cell 1
Authorisation
Type
Comments
Number Number
on-site off-site within
500m of the
site boundary
Discharge
consents
1
7
On-site licence relates to storm sewage overflow from Pembroke Road
Pumping Station
Off-site licences all relate to sewage discharges (four revoked) except one
which is for trade effluent discharge from a warehouse on East Street
Integrated
Pollution
Prevention
and Control
Permits
0
9
Four current and five superseded permits for BAE Systems fleet support
services on HM Naval Base
Local
Authority
Pollution
Prevention
and Control
Permits
0
8
Permits refer to: waste oil burners on ‘The Hard’ for; coating of metal and plastic
on Fleet Way; dry cleaning on Palmerston Road; waste oil burning on Malvern
Road; Petrol filling station on Richmond Road; Waste oil burning on Richmond
Road; dry cleaning on Albert Road; Petrol filling station on Highland Road
Radioactive
Substances
Registrations
0
12
All relate to HM Naval Base for the disposal of radioactive waste (nine
superseded and three current)
Authorisation
Type
Comments
Number Number
on-site off-site within
500m of the
site boundary
Pollution
Incidents
3
6
On-site incidents relate to bund overtopping at Gun Wharf in 1999 (the
pollutant is listed as clay); release of oils from Southsea beach in 1999; release
of oils from a road traffic accident on Clarence Esplanade in 1995.
Off-site incidents relate to surcharged sewage release at the Harbour Road slipway
in 1993 and released of caustic wash down chemicals to sea 380m north of the
Flood Cell in 1994; release of diesel due to a containment failure at camber dock
in 1999; release of oils from Clarence Parade in 1992; release of oils from a
traffic accident on Alhambra Road in 1996; release of petrol from a domestic
residence on St Romans Road in 1997. All incidents were categorised as minor
Prosecutions
relating to
Authorised
Processes
0
1
Prosecution for failure to ensure correct disposal of household waste 106m
east of the Flood Cell in 2003
Substantiated
Pollution
Incident
Register
0
1
Relates to significant impact to water by storm sewage discharge in 2001,
356m north of the Flood Cell
Contemporary
Trade
Directory
Entries
5
7
Active industries identified on-site are: marine engineers and chandlers.
Licensed
Waste
management
Facilities
0
1
Relates to a special waste transfer station operated on HM Naval Base 340m
NW of the Flood Cell
Fuel Stations
0
3
Fuel station entries refer to:
Inactive entries for the site include: domestic door manufacture, boat builders
and repairers, sail makers and repairers.
Off-site industries include manufacturers (unspecified, active) at The
Admirals, Gunwharf Quays; commercial cleaning services (inactive)
(1) White Heather Garage, Richmond Road, 273m west of the Flood Cell (open)
(2) Southsea Service Station, Victoria Road South, 411m north west of the
Flood Cell (closed)
(3) Highland road Service Station, 386m north east of the Flood Cell (closed).
8.2 Flood Cell 2 – Fraser Battery/ Eastney
Authorisation
Type
Comments
Number Number offon-site site within
500m of the
site boundary
Discharge
consents
2
19
On-site consents:
(1) Marples International Ltd Decontamination Unit, Langstone Marina Dev.
Revoked 1997
(2) Daniel Homes Ltd, Langstone Marina Village. Revoked 1996
Off-site consents refer to trade effluent and sewage discharges to the harbour
Authorisation
Type
Comments
500m of the
site boundary
Pollution
Incidents
0
10
All relate to minor releases, mainly of oils or sewage. Most recent 1998
Substantiated
Pollution
Incident
Register
0
3
(1) significant impact to water; minor impact to air – gas and fuel oil release
in 2001, 23m from site
(2) significant impact on water and land – sewage release in 2010, 140m
from site
(3) significant impact on water; minor impact on land – storm sewage release
in 2006, 169m from site
Contemporary
Trade
Directory
Entries
8
2
On-site industries include boat builders and repairers and marine engineers
on Fort Cumberland Road (both active); diesel engine equipment and
services (inactive) on Henderson Road; commercial cleaning services on
Lumsden Road (inactive)
Historical
landfill Sites
4
0
Locations named as:
(1) The Glory Hole, Ferry Road – accepted wastes including commercial and
household (Fig 2 Ref 17)
(2) Eastney Lake – accepted wastes including industrial, commercial and
(3) Henderson Road Caravan Park – accepted wastes including industrial
and commercial (Fig 2 Ref 70)
(4) Site B South of Ferry Road – accepted wastes including commercial and
8.3 Flood Cell 4 – North Portsea Island
Authorisation
Type
Comments
500m of the
site boundary
Discharge
consents
8
23
On-site consents:
(1) 4 for storm sewage overflow from Cosham Pumping Station (3 revoked)
(2) 2 for trade effluent discharge from Kendalls Wharf (both revoked)
(3) discharge of treated sewage from a site at Ports Creek (revoked)
(4) storm sewage overflow from Court Lane Pumping Station (revoked)
(5) surface water discharge from Alexandra Park
Off- site consents refer to discharge of treated sewage to soakaway, storm
sewage overflow from Mainland Pumping Station; St Andrews Road, Burrfields
Road and Kirtley Close Drayton Combined Sewer Overflows, cooling water,
trade effluent and surface water from sites on Walston Road; site drainage
from Paulsgrove Landfill Site; surface water from Trafalgar Wharfs, Tipner
Authorisation
Type
Comments
500m of the
site boundary
Integrated
Pollution
Control
Permits
0
4
Integrated
Pollution
Prevention
and Control
Permits
0
2
Local Authority
Integrated
Pollution
Prevention
and Control
Permits
0
1
Relates to revoked permit for printing activities on Limberline Road, Hilsea
Local
Authority
Pollution
Prevention
and Control
Permits
1
29
On-site permit is for blending, packing, loading and use of bulk cement at
Kendall’s Wharf (Fig 1 Ref 59).
Radioactive
Substances
Registrations
0
6
All relate to activities of Pall Europe Limited on Walton Road for the disposal of
radioactive waste. All either revoked or superseded
Pollution
Incidents
2
18
On-site incidents were both minor and occurred in 1995 and 1998. Both
related to releases of oils into Port Creek
Relate to inorganic chemical processes (use of mercury and cadmium
compounds) at Portsmouth Aviation Ltd, Airport Service Road (Fig 1 Ref 72)
Off-site permits relate to Star Service Station (Fig 1 Ref 73), Eastern Road,
coating of metal and plastic/spraying of road vehicles/
waste oil burners /quarry processes on Ackworth Road, coating processes at
Airport Service Road (Fig 1 Ref 54), surface treatment of metals/coating of
metal and plastic/blending, packing, loading and use of bulk cement/
di-isocyanate processes/manufacture of plastics on Walton Road, aluminium
& aluminium alloy processes/coating of metal and plastic at Broad Oak
Works on The Airport site (Fig 1 Ref 54); textile coating/rubber processing on
Airport Service Road; coating of metal and plastic on Dundas Lane;
Portsbridge Service Station (Fig 1 Ref 74); blending, packing, loading and use
of bulk cement at Tipnor Point & Tipnor Wharf(Fig 1 Ref 75), spraying of road
vehicles/ petrol filling stations/dry cleaning/printworks on London Road;
waste oil burners on Hartley Road; coating of metal and plastic on Gunstore
Road
Two off-site incidents were classed as ‘significant’. These relate to gas
oil releases to water at Walton Road in 1965 and 1996 respectively. The
remainder were classed as minor incidents and occurred in 1998 or before
Substantiated
Pollution
Incident
Register
0
Contemporary 3
Trade Directory
Entries
7
(1) significant impact to air by dust emission; no impact to land or water in 2010
(2) significant impact to water by an unidentified contaminant in 2003 near
Hilsea Bastion Gardens/recreation ground
(3) four incidents in 2002 and 2003 at the same location in the Tipner area,
three relating to construction/demolition and asbestos wastes and one to
release of fumes to atmosphere
13
On-site entries relate to cleaning services (inactive) on Salterns Avenue and
aggregates/concrete at Kendal Wharf (active)
Authorisation
Type
Comments
500m of the
site boundary
BGS Recorded 0
Landfill Sites
1
Licence refers to Paulsgrove Tip on Southampton Road (Fig 2 Ref 76)
Historical
landfill Sites
11
On-site landfills relate to:
8
(1) Land South of Burfields Road – accepted wastes including household (Fig
1 Ref 77)
(2) Land East of Baffins Pond – accepted wastes including household (Fig 1
Ref 78)
(3) Milton Common – accepted wastes including industrial and household
(Fig 1 Ref 44)
(4) Great Salterns Quay – accepted wastes including household (Fig 1 Ref 45)
(5) Sports Field East of Eastern Road – accepted wastes including
household. Last accepted waste in 1960 (Fig 1 Ref 79)
(6) Kendalls Quay, Anchorage Park – deposited wastes unknown (Fig 1 Ref 59)
(7) Alexandra Park, Normandy Road – accepted wastes including household
(Fig 1 Ref 62)
(8) Horsea Allotments – accepted wastes including household (Fig 1 Ref 80)
Of-site landfills relate to:
(1) Site at North Harbour – accepted wastes including industrial and
(2) Reclaimed Land in Paulsgrove Area – accepted wastes including
commercial and household (Fig 1 Ref 76)
(3) Stamshaw Area Site A – accepted wastes including inert (Fig 1 Ref 82)
(4) Stamshaw Chemical Works – accepted wastes including industrial (Fig 1
Ref 60)
(5) King Geroge V Playing Field, North Harbour – accepted wastes including
industrial and household (Fig 1 Ref 83)
(6) Tipner – Stamshaw, Gladys Avenue – accepted wastes including inert,
industrial and household(Fig 1 Ref 84)
(7) Tipner – Stamshaw Area 1, North of Newcomb Road – accepted wastes
including inert, industrial and household (Fig 1 Ref 85)
(8) Stamshaw Area Site B, adjacent to Waldern Road – accepted wastes
including inert (Fig 1 Ref 85)
(9) Reclaimed land In Pauslgrove Area – accepted wastes including
commercial and household (Fig 1 Ref 76)
(10) MoD site, Tipner – no waste types supplied. Last accepted waste in
1970 (Fig 1 Ref 85)
(11) Paulsgrove Tip, Southampton Road – accepted wastes including inert,
industrial, commercial, household, special waste and liquid sludge (Fig 1 Ref 77)
Registered
Landfill Sites
0
1
Paulsgrove Landfill Site accepted degradable commercial, household and
industrial wastes, difficult wastes, inert materials and special wastes (Fig 1
Ref 76)
Authorisation
Type
Comments
500m of the
site boundary
Licensed
Waste
Management
Facilities
0
9
Registered
0
Waste Transfer
Sites
5
Registered
Waste
Treatment or
Disposal Sites
0
3
Relate to:
(1) An operational scrapyard on the Ackworth Road Industrial Estate, Hilsea
(2) A former cardboard and plastic recycling centre at Venture Industrial Park, Hilsea
(3) An operational scrapyard on the Airport Industrial Estate
0
Control of
Major Accident
Hazards
(COMAH) sites
1
This relates to a site operated by RS Hill & Sons at Limberline Industrial
Estate (Fig 1 Ref 86), Hilsea but is indicated no longer to be in use
Explosive Sites 0
1
This relates to a site owned by Portsmouth Aviation Ltd at Portsmouth Airport
Notification of
Installations
Handling
Hazardous
Substances
(NIHHS)
0
2
These relate to:
- The RS Hill & Sons site, (see above) and is listed as active (Fig 1 Ref 86)
- PD Wharfage Ltd at Tipner Wharf (Fig 1 Ref 75)
Planning
Hazardous
Substances
Consents
0
3
These relate to
- The RS Hill & Sons site (see above) for use of gases flammable in air (Fig 1
Ref 86)
- Stagecoach South Ltd on Walton road for use of flammable liquids
- PD Wharfage at Tipner Wharf for use of flammable gases (Fig 1 Ref 75)
7
These relate to :
- Portsbridge Service Station on Portsmouth Road (open) (Fig 1 Ref 74)
- Eastern Road Service Station (open) (Fig 1 Ref 73)
- Portsmouth Truckstop & Lorry Park, Walton Road (status not known)
- Hilsea Service Station, London Road (closed)
- Shell Bastion, London Road (open) (Fig 1 Ref 87)
- Ophir Service Station, London Road (closed)
- Boundary Filling Station on London Road (closed)
Fuel Stations
These licences and registrations identify:
(1) Two household/commercial/industrial waste transfer stations at Central
Depot on Eastern Road which handles inert and non-hazardous wastes
including metals, paper, plastics, litter and green wastes and also asbestos
and construction/demolition/road maintenance wastes
(2) A metal recycling site at Artillery Row, Ackworth Road Industrial Estate, Hilsea
(3) A physical treatment facility (Bridge Skips Ltd) and a household/
commercial/industrial transfer station at Howards yard, Ackworth Road
(4) A household/commercial/industrial waste transfer station at Walkers Yard,
Ackworth Road Industrial Estate
(5) A recycling/reclamation centre at Venture Industrial Park, Hilsea,
accepting cardboard and plastic for recycling
(6) Pyramids at Paulsgrove Landfill Site, Port Way
(7) Portsmouth Water Plc transfer station at Portsbridge Depot, handling
highways construction/maintenance wastes
(8) Scrapyard at Airport Industrial Estate (Fig 1 Ref 54)
9
EXISTING CONTAMINATED LAND INVESTIGATION
REPORTS
9.1 PICSS Contamination/Risk Assessment Report
This report, completed by Halcrow Group Ltd for PCC as part of the
PICSS in 2004, provides valuable summaries of land quality reports
connected with areas of landfilling around the Portsea Island coast. The
report was therefore reviewed in order to capture information from the
previous phase of assessment. A summary of the findings of this review is
provided in Table 9.1.
Table 9.1: Summary of PICSS Contamination Report
Aspect
●● Description
Scope
●● An initial assessment of risks from waste landfill areas on
Portsea Island to the adjacent nature conservation sites under
the Habitats Regulations should the coastal defences not be
maintained
●● Did not consider the wider risk posed by land contamination to
human health, controlled waters and the environment
Information
Sources Used
●● Previous consultants’ reports
●● Information from PCC (a search of records office for landfill
licensing information; numerous desk studies and site
investigations at several sites commissioned/undertaken by
PCC)
●● Consultation with the Environment Agency (on current and
former landfill site, abstraction licences, discharge consents,
water quality data and pollution incidents)
Contamination
Sources
Considered
●● Landfill sites – numerous landfills operated since the 18th Century
Receptors
Considered
●● Harbour water quality
●● Contaminants listed as metals, oils/tars, sulphates, cyanides
and asbestos
○○ Portsmouth Harbour to the west (the northern part is a SPA for
birds and a Ramsar site and the Harbour is a SSSI)
○○ Langstone Harbour to the east (forms part of a SPA, Ramsar
Site and The Solent candidate SAC and the harbour is a SSSI)
●● Flora and fauna – particularly species protected under the
Habitats Regulations
●● SSSIs, cSACs, SPAs and Ramsar sites were identified as
ecological receptors for contaminated land (DETR Circular,
September 1999)
Pollutant Linkages ●● Release of wastes into the harbour via coastal defence breach
Considered
●● Release of leachate into the harbour through the sea wall
●● Accelerated release of leachate due to flooding
●● Migration of surface runoff
●● Migration of liquates via permeable strata (either through or over
sea defences)
●● Release of landfill material due to a collapse of the sea defence
●● Potential for leachate to build up behind sea walls and overflow
during long periods of wet weather
Aspect
●● Description
Identified Landfill
Sites
●● Within the study areas (Flood Cells 1 and 4)
●● Kendall’s Quay
●● Sportsfield Est of Eastern Road
●● Great Saltern Quay
●● Land South of Burfields Road
●● Land East of Baffins Pond
●● Milton Common
●● Horsea Allotments
●● Alexandra Park
●● Landfills inland of study area
●● Victoria Trading Estate
●● Hilsea Gasworks
●● Longmeadow Allotments
●● Moneyfield Allotments
Reported Risk
Assessment
Conclusions
Release of contaminants following a breach (landfill waste
release): Moderate risk
Continuing release of leachate via permeable sections of sea wall
and drains: Moderate risk
Release of leachate due to coastal flooding via permeable
sections of sea wall and drains: Low risk
Uncertainties/
Relevance to
Schemes
●● Risk of unexploded ordnance in waste due to presence of rifle
ranges and potential historic explosive manufacturing
●● Cell 2 indicated to contain ship breaking wastes and asbestos
●● Cell 4 Indicated to contain unlined domestic refuse, clinker and
ash, demolition waste, incinerator ash
●● The report notes evidence of possible disposal of ‘toxic waste’
from chemical works, but the date, composition and locations
were not certain
The collation of site investigation data indicates elevated levels of
some contaminants (e.g. metals, total PAHs, sulphate) but testing
did not include speciated PAH, Total Petroleum Hydrocarbons
(TPH) or asbestos
N.B. The report text and appendices were available for review but
some report figures were missing
9.2 Reports from the Portsmouth City Council Contaminated Land
Archive
In order to provide additional information on areas of land which may be
affected by the Schemes, the Eastern Solent Coastal Partnership provided
ten reports from the PCC Contaminated Land archive for review as part of
this Scoping Stage.
These reports were selected from the archives by limiting the archive
search to land in, or within 250m of the study areas, in partnership with
the PCC Contaminated Land team and Eastern Solent Coastal
Partnership. The reports were then selected on the following basis:
●● Contaminated land focused reports (rather than geotechnical);
●● Sites for which there is little information in the Envirocheck on the
actual use;
●● Reports not already reviewed in the PICSS (Halcrow, 2004) report;
●● In general, reports were selected for review for each site with the
following order of preference; remediation reports, site investigation
and desk studies. This approach has been taken to reflect the order in
which these reports will have been produced i.e. a remediation report
will have been produced most recently giving information on the most
recent condition of the site;
●● Reports for more sensitive areas of the site (e.g. not those for sites
north of Ports Creek since the creek is likely to act as a hydraulic barrier).
The outputs from the archive search are provided in Annex 4 and give
details of all the reports available, from which the ten were selected.
The study area may be impacted by areas of contaminated land within its
boundary or by off-site sources where contaminants are able to migrate
onto the study area. Areas of contaminated land or groundwater outside
the study area boundary might also be affected by the Schemes if the
development causes any changes in the groundwater regime. Changes in
groundwater levels or flow direction might, for example, provide pathways
for contaminant migration. The sites selected were therefore either in or
very close to the study area
The reports selected were:
1. ESI (2010). Canoe Lake Contaminated Land Investigation: Detailed
Inspection and Assessment of Canoe Lake, Portsmouth
2. Parkman Buck Ltd (1993). The Glory Hole Eastney Quantified Risk
Assessment for the Glory Hole Eastney Vol 1 & 2
3. Hyder Consulting (2000). Eastney Married Quarters, Portsmouth:
Method Statement in Support of Planning Application
4. Clayton Environmental Consultants Limited (1995). Ground
Investigation, Tangier Road Portsmouth
5. Soils Limited (2007). Report on a Ground Investigation on Kendalls
Wharf, Eastern Road, Portsmouth
6. ERM (2009). H&S Aviation, Portsmouth, Human Health Generic
Quantitative Risk Assessment
7. Parkman Buck Limited (1993). Alexandra Park, Portsmouth
Contaminated Land Site Investigation Report
8. Leigh Analytical Services (1994). Horsea Allotment Ground
Investigation
9. Parkman Buck Limited (1993). Tipner Quay, Twyford Avenue, Desk
Study
10.PCC and Wimpey Homes Holdings Limited (1997). Agreement in
Pursuance of Section 106 of the Town and Country Planning Act 1990
and Section 111 of the Local Government Act 1972 relating to Former
HMS Phoenix Site, Matapan Road, Stamshaw, Portsmouth
The information contained within these reports and its potential significance
for the next stages of the project is summarised in the sections below. The
approximate locations and extent of the sites are shown on Figure 6 in Annex
2. Although the reports contain information which is considered useful in
understanding the history of contamination issues associated with the
sites, many are several years old and produced before publication of the
current contaminated land quantitative risk assessment frameworks were
published. The fieldwork data may no longer be representative of current
site conditions and the assessments are unlikely to be against currently
acceptable criteria. Further testing and assessment is therefore likely to
be necessary should works be planned in the vicinity of these sites.
9.3 Canoe Lake
able 9.2: Summary of Land Quality Report for the Site at Canoe Lake
T
(within Flood Cell 1)
Aspect
Description
Site Location/
Extent
Public open space surrounding Canoe Lake
Scope of
Assessment
This report was prepared for PCC to support their investigation
of the site under Part 2A of the Environmental Protection Act
and focused on human health risks and excluded risks to other
receptors, including controlled waters
Land Use Site
History
Part of the Great Morass extended beneath the lake. Made into
public gardens and Canoe Lake constructed in the late 19th
century with later additions of car parks, public conveniences,
children’s playground etc. During World War II the area between
Canoe Lake and Lumps Fort was used by the military. Canoe
Lake is indicated to be clay lined
Geology and
Hydrogeology
Tidal Flat Deposits (an Undifferentiated Secondary Aquifer) and
River Terrace Gravels (Secondary A Aquifer). These are underlain by
Earnley Sand and Marsh Farm Formations (Secondary A Aquifers)
Aspect
Description
Assessment of
Contamination
A desk study for the site indicated that the area had been used to
dispose of rubbish. The origin of any fill material used to landscape
the site when the lake and gardens were created was not known.
An infilled gravel pit was also identified to the north east of the site.
Elevated concentrations of lead and benzo(a)pyrene were detected
within the top 2.5m of soil during a preliminary site investigation
centred on a new playground area. The origin of the contamination
was not established. A subsequent detailed investigation of the site
focussed on shallow soil samples (between 0.1mbgl and 0.5mbgl).
The materials encountered in the shallow excavations were
consistent with infill material deposited in the late 19th Century
(i.e. containing brick and glass but not plastics). The assessment
concluded that elevated lead (and zinc) concentrations were likely
to be only in very localised areas. No asbestos was detected. Elevated
heavy fraction TPH and PAHs were noted. TPH was attributed to
two separate sources. The assessment concluded that none of the
contaminants were assessed as posing a ‘significant possibility of
significant harm’ (SPOSH) to human health
Uncertainties/
Relevance to
Scheme
No assessment of risks to controlled waters was undertaken.
The site investigation focussed mainly on shallow contamination.
Additional contamination may be present at depth
Although shallow soil contaminant levels were found not to constitute
SPOSH, they may not be suitable for reuse if excavated as part
of the Scheme, since risk assessment for development planning
applications is undertaken at a lower risk level than SPOSH
9.4 The Glory Hole, Eastney and Remediation of the Eastney Barracks
Married Quarters (within Flood Cell 2)
The PCC Contaminated Land archive GIS reports indicate that the Eastney
Barracks Married Quarters appear to overlie the former Glory Hole area of
landfilling. The Quantitative Risk Assessment reports (volumes 1 and 2)
for the Glory Hole (1993) have therefore been reviewed in order to provide
information on the contamination originally present as a result of the
landfilling and military use. The Remediation Method Statement report for
the Married Quarters (2000) has been reviewed in order to establish
whether all risks were addressed by remediation or whether some may
remain. No verification report for the remediation was identified.
Table 9.3: Summary of Land Quality Report for the Eastney Barracks
Aspect
Description
Site Location/
Extent
The remediation area comprised:
Front of Finch Road Flats “North East”
Finch Road Flats North Areas – Odd Numbers 1-69 inclusive
Finch Road Flats South Areas – Odd Numbers 1-47 inclusive
Ferry Road South and Gibraltar Road North West Houses
Finch Road Flats – Even Nos 2-36 and 38-48
Finch Road Flats – Works to the Rear of Even Nos 2-36
Communal Area to Rear of Even Nos 2-8 Gibraltar Road
Gibraltar Road North – Front Gardens Nos 24-2
Gibraltar Road South – Front Gardens Nos 27-13
Gibraltar Road South – Front Gardens Nos 11-1
Ferry Road Flats – Fenced Back Garden Areas
Scope of
Assessment
The report risk assesses data gathered by previous investigations:
AEA Harwell August 1985
AEA Harwell August 1991
AEA Harwell November 1991
AEA Harwell December 1991
PSA August 1886
PSA October 1986
J. Locke March 1993
PCC November – February 1992
Land Use Site
History
Historic use as a landfill for naval wastes. MoD commenced
landfilling in 1930. No records were kept.
Between 1956 and 1966 the MoD built housing on the former tip.
Investigations indicated no capping layer was installed.
In 1971 the Council bought a section of the site (Eastern
Glory Hole). Between 1980 and 1985 a site investigation was
undertaken prior to construction of a marina in 1985-1987 and
marina village in 1986-1992. In 1986 and 1987 the council
“leased sections of the Lumsden Road Estate in order to fulfil its
commitments to Council housing stock”.
Further testing carried out by both the MoD and Portsmouth
Housing Association in 1991. PCC took a precautionary step of
removing its tenants from the site.
In 1992 MoD asked for bids for purchase of some of the housing.
1992 an enquiry was carried out to determine whether all
practicable steps were taken to safeguard the future wellbeing of
residents and users of the site.
Geology and
Hydrogeology
Not discussed.
Aspect
Description
Assessment of
Contamination
Previous investigations identified the presence of contaminants
including asbestos, cadmium, lead and mercury. Boron, chromium,
cobalt, molybdenum and cyanide were concluded probably to
“exist at the site in background levels”.
The risk assessment cited the following principal concerns:
●● Potentially toxic dose for children from consuming soil;
●● Potential chronic risks to children mainly from soil lead
concentrations;
●● Risks from inhalation of asbestos (mainly from children playing
in soils where asbestos matting or rope is exposed);
●● Insufficient data on soils and tars to allow full risk assessment;
●● No analysis of PCBs, pesticides, dioxins or radionuclides;
●● No chromium speciation;
●● No assessment of exposure from ingestion of contaminated fish
and shellfish from the adjacent creek; and
●● No testing for PAHs or chlorinated solvents.
Remediation
Method Proposed
A thickness of contaminated soil to be removed from gardens and
open space and replaced with a barrier system of clean granular
material and topsoil. Installation of a gas venting system. It is
indicated that residents remained in-situ during remediation.
Gibraltar Road front gardens – excavation of 350mm of material,
laying of a geotextile separator and backfilling with clean material.
Communal areas – excavation of 100mm of material, laying of a
geotextile separator and backfilling with clean material.
In some communal areas, no excavation but raising of existing
ground level using 250mm of clean material.
Noted that contaminated groundwater existed beneath the site,
although this was described as ‘relatively immobile’ and posting
‘an acceptable risk to the wider environment’. Excess application
of water prohibited to avoid leachates being formed which could
impact surface water or groundwater quality.
Radiological screening. The report notes that “there is a high
degree of confidence that the radioactive dial which was located
and has since been removed is the only significant source within
soil to 500mm depth”.
A principal concern during remediation appears to have been the
release of asbestos fibres.
Uncertainties/
Relevance to
Scheme
●● Due to the age of this study, the quantitative risk assessment
approach used may not be compliant with current guidelines
●● The majority of soil samples appeared to be from shallow depth,
with the maximum depth of sample being 2.9mbgl. All results
appeared to be for total contaminant concentrations in soil, with
no soil leachate or groundwater testing
●● Contamination is indicated to remain below the capping layer
and some contaminants may be present in leachable form,
potentially presenting a risk if the land is eroded or inundated or
if groundwater conditions change
9.5 Tangier Road Ground Investigation (adjacent to Flood Cell 4)
Table 9.4: Summary of Ground Investigation, Tangier Road
Aspect
Description
Site Location/
Extent
An area of approximately 8.5ha of predominantly grassed, flat
public open space in the east of Portsea Island, to the west of
Portsmouth Sixth Form Collage and to the east of Baffins Pond
Scope of
Assessment
Drilling of 79 window sample holes either to 2mbgl or to base of fill
(maximum of 4mbgl) on a 30m grid, and an additional 13 on land
previously occupied by an incinerator and two highway depots.
These supplemented 18 existing boreholes. 85 soil samples
recovered from 0.2- 0.5mbgl and 26 deeper samples.
The aims were to:
●● Characterise the nature, degree and extent of contamination
including in groundwater beneath the site;
●● Provide data for risk assessment for the current and intended
future use of the site; and
●● To determine the concentrations of methane, carbon dioxide and
oxygen in probe holes in the south and east corner of the site.
Gas monitoring was undertaken within 44 probe holes in the
south and east of the site, where domestic waste landfilling was
suspected during drilling.
Water and sludge samples recovered from land drain interceptors.
Land Use Site
History
An area of public open space intended for redevelopment as
a secondary school. The report references a potential area of
domestic landfilling in the south and east of the site.
Geology and
Hydrogeology
The site investigation encountered grass over an average of 0.1m
of topsoil containing fragments of brick, ash etc. in places. This
was found to overlie Made Ground of gravelly sandy ash, glass
and brick fill often mixed with clay fill (maximum depth 3.55mbgl)
overlying alluvium (with an intervening layer of black peaty gravel
in places), with clay beneath.
Groundwater was encountered at an average depth of 1.6mbgl.
The report concluded that groundwater was probably in continuity
between the different strata encountered and that groundwater flow
was likely to be towards the north east but could not be confirmed.
Aspect
Description
Assessment of
Contamination
Contaminant concentrations were assessed against the (now
withdrawn) ICRCL trigger values for parks playing fields and open
space and, for some areas, domestic gardens. Soil leachate and
groundwater contaminant concentrations were assessed against
the Dutch Intervention Values.
A yellow viscous oil was encountered at one location, possibly due
to the window sampler puncturing an oil container.
pH was noted to be generally neutral or alkaline, although an
acidic pH of 3.7 was recorded in one location.
Elevated concentrations of lead, PAHs, mercury, arsenic, copper,
zinc, antimony and phenol were found in shallow samples with
similar but generally lower concentrations in the saturated zone.
Leachability testing indicated mobile lead, barium, mercury and PAHs.
Groundwater sampling indicated elevated lead, mercury,
zinc, copper and PAHs so it was considered possible that
leachable contamination was able to migrate off-site. Significant
concentrations of methane and carbon dioxide, with depleted
oxygen levels, were detected in the south east of the site.
Widespread elevated sulphate concentrations were noted.
Cement sheeting was found in one location.
The yellow oil was found not to contain either PCBs or PAHs (at a
level considered to be significant).
A maximum of 17% methane was detected but this was noted to be
associated with the alluvium rather than the fill material. Carbon
dioxide up to 2.25% and depleted oxygen levels were also recorded.
Uncertainties/
Relevance to
Scheme
Four reports were available for this site:
●● A risk assessment of public open space
●● A ground investigation report
●● A geotechnical report
●● A risk assessment of open space to be developed into a
secondary school
Of these, the ground investigation report was reviewed since the
risk assessments did not follow current best practice methodologies
and the geotechnical report was considered unlikely to be relevant
to contaminated land assessment. The risk assessment contained
in the site investigation report uses thresholds which have since
been withdrawn, therefore the results should be treated with caution.
The site investigation report recommended the preparation
of a method statement for remedial works at the site prior to
redevelopment. If remediation was subsequently carried out,
risks from contamination may have been significantly reduced.
However, it is possible that this area of the Flood Cell still
contains contaminated soil with some contaminants present in
leachable form, potentially allowing migration of contamination
as a result of inundation, infiltration or change in groundwater
regime. Contamination may also remain in shallow soils, if left
unremediated, potentially posing a risk to human health.
9.6 Kendalls Wharf (within Flood Cell 4)
Table 9.5: Summary of Land Quality Report for the Site at Kendalls Wharf
Aspect
Description
Site Location/
Extent
Site investigation covered an industrial site between the A2030
Eastern Road and the access road to Kendalls Wharf, north of the
sports ground
Scope of
Assessment
Geo-environmental investigation for contaminated land
assessment and foundation design for a new development. The
nature of the development was not described
Land Use Site
History
The Site Investigation Report does not provide a summary of the
site history but does make reference to the presence of reclaimed
land in proximity to the site
Geology and
Hydrogeology
Made Ground underlain by Head Deposits (orange brown to
dark blue/grey slightly sandy gravelly clay) and the Upper Chalk
Formation (classified at the time the report was written as a Major
Aquifer; now a Principal Aquifer)
Assessment of
Contamination
Made Ground was described as dark brown/orange brown sandy
gravelly clay with abundant brick, ash, clinker and concrete fragments.
Shallow soil samples (taken from the top 1.1m) were analysed for
heavy metal, benzo(a)pyrene and asbestos and assessed against
residential with plant uptake assessment criteria (assuming that
the development might include residential use with gardens).
Elevated concentrations of several metals and benzo(a)pyrene
were noted in the Made Ground, but no asbestos fibres were
detected. During initial gas monitoring, elevated concentrations
of carbon dioxide were detected but no methane. Further gas
monitoring accompanied by groundwater monitoring was planned.
No leachate or groundwater testing was reported. The report
recommended removal of Made Ground if the site was
redeveloped for residential use but also recommended further
monitoring, testing and assessment of risks to groundwater and
risks from ground gases
Uncertainties/
Relevance to
Scheme
●● No assessment of risks to controlled waters was undertaken
●● Some contamination was detected in soils
●● Unless remediation has since been undertaken at the site to
address the contamination, risks may remain to human health
and potentially also to controlled waters
●● Any soils excavated as part of the Scheme may not be suitable
for reuse. Any contamination in leachable form may be mobilised
by inundation, infiltration or change in groundwater regime
9.7 H&S Aviation Site (adjacent to Flood Cell 4)
Table 9.6: Summary of Land Quality Report for the Site at H&S Aviation
Aspect
Description
Site Location/
Extent
H&S Aviation site of approximately 5.2 acres, located off Airport
Service Road on an industrial estate to the south of the A27 and
west of the A2030. The site comprised four workshops, two test
bed buildings, a chemical store and an office block
Scope of
Assessment
Site investigation was undertaken in 2008, with additional
investigation, designed to fill data gaps in the human health
quantitative risk assessment, in 2009.
Restricted to two specific areas of the site proposed for the construction
of new test beds; one located on the site of a chemical store.
This included indoor air monitoring for volatile organic compounds.
Land Use Site
History
The site is indicated to have been reclaimed from marshland before
becoming part of the Napoleonic Hilsea Lines fortifications. These
were later reconstructed with brick, earth and a moat. With the
development of Portsmouth Airport in the 1920’s areas of the site
were levelled, resulting in the partial infilling of the moat. Aeroengineering development followed, with hangars, engine test cells
and associated waste processing and storage, and chemicals and
oil storage. Other industrial usages of adjacent land were noted,
including a timber yard.
The airport site was later redeveloped for housing and industrial use.
Several previous ground investigations had been carried out between
1996 and 2007 which highlighted contaminated groundwater (and
some soil) by chlorinated and non-chlorinated hydrocarbons
(including petroleum hydrocarbon free product). The petroleum
hydrocarbons were indicated to be derived from kerosene from
accidental spills or leaks from underground storage tanks and pipes.
In 1999 remediation was undertaken to treat volatile organic
compounds in the chalk groundwater which is indicated to have
been a combinations of hydraulic containment and ‘pump and treat’.
Simultaneously, free product was pumped from the shallow strata.
Further impacted soil and groundwater were removed during site
redevelopment in 2005.
Geology and
Hydrogeology
Identified, by site investigation, to be concrete over Made Ground
(aggregate over varied cohesive and granular soils). Beneath this
were Holocene silty clays, cut through in the west of the site by a
channel complex of gravelly and silty sands overlain by silty clay.
These overlay Head Deposits and the Upper Chalk.
The Made Ground and drift deposits contained water.
A layer of putty chalk confined groundwater in the Upper Chalk
and was indicated to inhibit contaminant migration.
Aspect
Description
Assessment of
Contamination
The QRA undertaken focused only on risks to human health. Risks
to controlled waters were not discussed in detail.
Given similar industrial uses on nearby sites, off-site contaminant
sources were not ruled out.
Risks to human health from direct contact were not considered to
be significant due to the presence of a layer of hard standing
across much of the site.
The assessment focussed on risk from organic vapours from soil
and groundwater, dust inhalation and risks from soil gases.
The report concluded that risk to human health did not warrant
additional remediation, assuming continued industrial usage of the
site but recommended further routine monitoring. Ground gas
protection measures were recommended for the new development
Uncertainties/
Relevance to
Scheme
The report indicates that remediation was undertaken at this site
to address soil and groundwater contamination. However, it notes
that nearby sites have had a similar industrial past. It is not known
if these were also contaminated and whether they have since
been remediated. It is considered possible that significant soil and
groundwater contamination may remain in this industrial area
Soils excavated in this area as part of the Scheme may not be
suitable for reuse
Care should be exercised should any dewatering operations
encounter contaminated groundwater
Any leachable or dissolved contaminants present could be mobilised
by inundation, infiltration or change in groundwater regime.
9.8 Alexandra Park (within Flood Cell 4)
Table 9.7: Summary of Land Quality Report for the Site at Alexandra Park
Aspect
Description
Site Location/
Extent
An area covering 12.9ha located in the north west of Portsea Island.
Scope of
Assessment
Focused on the need to identify the nature of fill material and
assess the risk to local residents and site users and the potential
for landfill gas generation and migration.
Land Use Site
History
Indicated to have been a landfill site before 1989.
Geology and
Hydrogeology
Reported as consisting of alluvium and brickearth over Reading
Beds in the South and Upper Chalk in the remainder of the site.
The site investigation recorded fill comprising clays, silts and
domestic refuse (in isolated pockets) including bottles, ceramics,
ash and tins.
The clay and silt fill material encountered was considered likely to
be derived from estuarine deposits dredged from the nearby channels.
Aspect
Description
Assessment of
Contamination
A series of trial pits and boreholes were completed in 1993 and
samples were tested for phenols, cyanides and metals. Ground
gas measurements were also taken. Little degradable matter was
found in the Made Ground and, on this basis, no long term gas
monitoring was undertaken. A spike survey was completed. This
methodology is no longer considered best practice.
Chemical testing results were compared against the ICRCL levels
(which have since been withdrawn). There were exceedences
noted for copper, boron and zinc.
High arsenic concentrations were noted to be consistent with
background levels in Portsmouth. PAHs, recorded at up to
270mg/kg would now be considered elevated. However no
speciated testing was completed, which would now be required for
quantitative risk assessment. Occasional elevated levels of lead
were noted. Neutral to alkaline soil conditions were considered
likely to inhibit mobility and uptake of contaminants. Contamination
in groundwater was considered to be at a generally low level.
The report concluded that the site was suitable for its use as park
and playing fields without remediation. Some physical hazards
were highlighted due to the presence of broken glass in shallow
soils. Low levels of gas encountered were considered to be
consistent with estuarine/alluvial deposits. Asbestos was not
tested but considered unlikely to be present due to the age of the
fill and was not observed visually during the site investigation.
Uncertainties/
Relevance to
Scheme
●● The risk assessment compared contaminant concentrations
against thresholds which have now been withdrawn. The
report concluded that contaminant concentrations were not
unacceptably high. However, risk assessment using current best
practice methodologies might not produce the same conclusion.
●● Further testing and assessment would be needed to establish if
soils at the site were suitable for reuse, should excavations be
planned in this area.
9.9 Horsea Allotments (within Flood Cell 4)
Table 9.8: Summary of Land Quality Report for the Site at Horsea Allotments
Aspect
Description
Site Location/
Extent
Horsea Lane Allotments covering approximately 3.5ha at OS grid
reference SU650040 in the north west of Portsea Island.
Scope of
Assessment
An investigation of shallow soils was undertaken due to reported
crop failures and poor growth even of weeds in one area of
the allotments. 20 shallow pits were excavated on a 20m grid
to sample topsoil and some groundwater samples were also
recovered. Samples were tested for phenols, Total Organic
Carbon, Total PAHs, metals and pH.
Aspect
Description
Land Use Site
History
No history of industrial use was recorded but the land was
formerly owned by the war department. The site was indicated
to be pasture until after 1910; purchased by PCC from the War
Department in 1926; and to have been used as allotments since
before 1932.
Geology and
Hydrogeology
The investigation encountered topsoil with small amounts of
Made Ground (attributed to localised tipping of domestic waste
by allotment users) over clayey alluvium. A very high water table
was encountered at 0.3mbgl) perched in the topsoil overlying
clay. Brick fragments, china, glass rusted metal fragments, clinker
and ash as well as burnt and degraded paper, magazines and
cardboard were encountered in the Made Ground.
Assessment of
Contamination
Exceedences of zinc, mercury, lead, copper, cadmium, cyanide
and phenols were recorded when compared against the (now
withdrawn) ICRCL trigger levels. The report noted indications of
some hydrocarbons being present.
6 groundwater samples were tested and the results compared
against drinking water standards and the Dutch guidelines. The
results were reported to be generally below the ‘action levels’
used, although exceedences were reported for lead ,cadmium,
mercury, chromium, copper, molybdenum, cyanide and phenols.
Results from the testing of soil leachates were recorded as
being similar to groundwater results, indicating that groundwater
quality was related to the quality of the topsoil. Some limited
concentrations of methane were detected (to a maximum of
1.3%). Higher than background levels of zinc were attributed to
the use of gardening products at the site. Concentrations of many
contaminants were higher in topsoil than in Made Ground or
natural ground. This was attributed, in the report, to cultivation.
Uncertainties/
Relevance to
Scheme
●● The site investigation detected contaminants in both soil and
perched groundwater.
●● The risk assessment compared contaminant concentrations
against thresholds which have now been withdrawn. Risk
assessment using current best practice methodologies might not
produce the same conclusion.
●● Further testing and assessment would be needed to establish if
soils at the site were suitable for reuse, should excavations be
planned in this area.
9.10 Tipner Quay (adjacent to Flood Cell 4)
Table 9.9: Summary of Land Quality Report for the Site at Tipner Quay
Aspect
Description
Site Location/
Extent
The desk study covered an area of 2.3ha of industrial land around
OS grid reference SU644030.
Scope of
Assessment
Assessed published records and previous site investigation results
for the site.
Aspect
Description
Land Use Site
History
At the time of the desk study the northern third of the site was occupied
by a container stockyard; the centre was a cement loading depot;
and the southern third was a coal merchant’s yard. A military
hardware dismantlers (scrapyard) was adjacent to the north west.
The site was reported to be in agricultural use with fortifications in
1773 in the south, the northern two thirds not having been
reclaimed yet from the sea.
Part of the site was marked as ‘waste’ in 1838. Small clay pits and
brick works were indicated in 1840-1870. A chemical works was
visible in 1870-1923 with the clay pit infilled. A further brick pit was
shown in 1979 but infilled by 1898. By 1929 the chemical works had
become a tar distillery and National Benzole occupied the north of
the site with a tank farm including a road tanker filling depot and
quary. Some of the north of the site is assumed to have been
reclaimed by land raising. The tar distillery was sold in 1949 and
planning permission granted for conversion into a timber yard.
However, there are indications that this was never built and by 1956
the southern third of the site was occupied by a coal merchant’s.
The centre of the site was recorded as a cement depot by 1962
with the north sold to a shipbreaking company.
The quay may have become disused with the building of the
motorway in the 1970’s.
In 1985 consent was granted to change the benzole plant into a
plant hire yard.
Geology and
Hydrogeology
Site investigation in 1969 encountered up to 33m of blue and
brown sandy soft clay (Reading Beds); the top 4m comprised
loose yellow sand with Chalk beneath.
Made Ground was described as sandy clay (likely to be dredged
material). Green ash deposits were encountered on the sports field
to the south of the site, considered likely to have come from the tar
distillery. Groundwater was encountered between 1.5 and 2.0mbgl.
Assessment of
Contamination
The desk study highlighted contaminants associated with tar
distillation (including benzene, phenol, PAHs, and aliphatic
hydrocarbons and possibly cyanides, sulphur and ammonia
from associated processing). Fill material was considered likely
to contain boiler ash and clinker and coal dust was considered
likely to be present from coal storage. Methane, carbon dioxide,
hydrogen sulphide and hydrogen cyanide gases were considered
to be potentially present due to infilling and distillery activities.
Uncertainties/
Relevance to
Scheme
A number of intrusive site investigations are indicated to have been
undertaken on or around this site (which have not been reviewed at
this stage), although the site is not indicated to have remediation
reports associated with it. Information from the PCC Contaminated
Land Team (personal communication from L Williams to G Holder
01/05/2012) notes that “a lot of this area bordering the south shore of
Tipner Lake has contamination issues and a major redevelopment
is planned including housing and a new slip road from the motorway”.
It is understood that the Team have undertaken a review of a
number of contaminated land reports associated with this area.
Further information is therefore available from the Team should
this area be of concern to the Scheme.
9.11 Former HMS Phoenix Site, Matapan Road, Stamshaw, Portsmouth
(partially within Flood Cell 4)
Table 9.10: Summary of Land Quality Report for the Site at Matapan Road
Aspect
Description
Site Location/
Extent
An area of land lying to the north of Alexandra Park and to the
south of Horsea Allotments, adjacent to the coastal frontage.
Scope of
Assessment
Section 106 agreement between PCC and Wimpey Homes
Holdings Limited, October 1997, associated with planning
permission for development including the constructions of homes,
garages and parking, a children’s play area, public open space
and landscaping at the site. Schedule 5 provides a method
statement for remediation.
Land Use Site
History
Noted to be a former naval training school including workshops.
The method statement states that the majority of the site’s
drainage runs were contaminated with hydrocarbons and that
some were constructed with asbestos containing material. Pockets
or layers of ash were noted to have been found in a number of
locations. Hydrocarbon contamination was indicated to be present
in the south east corner of the site, identified by black streaks and
staining of the clay.
Geology and
Hydrogeology
Not described.
Aspect
Description
Assessment of
Contamination
The method statement included:
●● Demolition of remaining buildings, including those with asbestos
roofs.
●● Marking out of areas of contamination (the method statement
references a desk study completed by the Laboratory of the
Government Chemist which identified “ a number of locations
across the site where it was considered that contamination was
possible”).
●● Removal of the concrete slab in the north of the site and
remaining road with inspection of the ground underneath by an
environmental scientist.
●● Analysis of any areas considered likely to be contaminated.
●● Removal off-site to a licensed facility of any material found to be
contaminated.
●● Removal of contaminated drainage runs.
●● Removal and off-site disposal of ashy material encountered
within the soils.
●● Removal of hydrocarbon contaminated material beneath the
proposed housing area, and in any other areas where it was
encountered, for off-site disposal.
●● Placement of imported, clean topsoil and subsoil in garden
areas.
●● Placement of uncontaminated material from on-site and
imported topsoil to raise ground levels in the area of public open
space.
●● Control of stockpiling of contaminated and uncontaminated
materials.
●● Aeration of the Public Open Space (Southern Area) 6 months
prior to placement of clean material to reduce hydrocarbon
contamination.
Uncertainties/
Relevance to
Scheme
The site investigation and risk assessment reports for this site
have not been reviewed. However, if the Section 106 agreement
was adhered to, significant remediation appears to have taken
place at the site to remove shallow contaminated soils.
It is not clear if the contamination extended deeper and whether
risks to groundwater were considered.
A review of the relevant reports and further testing and
assessment would be needed to establish if soils at the site were
suitable for reuse, should excavations be planned in this area.
Should deep foundations or other potential pathways to
groundwater be planned as part of the Scheme, further
assessment of the risks to groundwater quality are likely to be
needed as this site is indicated to overlie the Upper Chalk.
10 INITIAL CONCEPTUAL SITE MODEL AND
PRELIMINARY RISK ASSESSMENT
In accordance with the Environmental Protection Act 1990, for contaminated
land to exist there should be a source of contamination, a receptor where
‘significant harm’ or ‘significant possibility of harm’ may be caused or pollution
of controlled waters is being or is likely to be caused and a pathway which
connects the two. Should any element of this contaminant linkage not be
present (or severed) then the land may not be regarded as contaminated
land, as defined in Part 2A of the Environmental Protection Act, 1990.
10.1 Conceptual Site Model
In accordance with the above approach, a conceptual model (sourcepathway-receptor linkage model) of the site has been produced, based on
the review summarised in Sections 6 to 9, and describes the likely sources
and pathways associated with the site and the potential receptors which
may be adversely impacted by a pollutant linkage.
This initial appraisal of land quality risks has identified a large number of
potentially contaminated sites within, or close to, the study area. The
following sections summarise some of the likely pollutant linkages which
may impact the Schemes. The conceptual model should be refined as the
design of the Schemes progresses.
10.1.1 Potential Contaminant Sources
Contamination sources can include neighbouring land uses and historical
activities both on and off-site. Within this contaminated land assessment,
a number of potential contamination sources have been identified in
Sections 6 to 9. These are shown in Figure 2 of Annex 2 and discussed
below. The potential sources can be grouped into seven broad categories:
●● Historic Landfilling – extensive landfilling appears to have taken place
along the eastern and north western coastal frontages of Portsea Island,
with low lying coastal land being reclaimed by infilling. A range of wastes
are indicated to have been disposed of in these areas, including domestic
and industrial wastes and military wastes within landfills operated by
the Ministry of Defence. Landfill sites also have the potential to produce
landfill leachate and hazardous gases, with the potential to migrate and
impact nearby receptors. Landfill sites may be associated with a very wide
range of contaminants, depending on the waste types accepted. These
may include (but not be limited to) asbestos, heavy metals, PAH, TPH,
Volatile Organic Compounds (VOC), Semi-volatile Organic Compounds
(SVOC), pesticides, explosives, pathogens, phenols, cyanides,
ammonium, chlorides and sulphates.
●● Industrial Estates and Industrial Premises – The Trade Directory entries
and authorisation records indicate the presence of a range of activities
including:
○○ Engineering- potentially associated with contaminants such as fuel
and lubricating oils, degreasing solvents and metals;
○○ Chandlery – may be associated with potentially contaminative
materials depending on the boating equipment stocked and whether
any manufacturing or repair activities are undertaken
○○ Cleaning – activities such as dry cleaning may use organic solvents
including chlorinated solvents
○○ Aggregate/concrete storage/processing – may be associated with
contaminants including fuels and lubricating oils from vehicles and
machinery and sediments (including alkaline sediments) from
concrete products,
○○ Waste management – waste management sites may be associated
with a range of contaminants depending on the wastes accepted
and the activities undertaken. These might include fuels, oils, metals
and antifreeze from vehicle dismantling but a much wider range of
potential contaminants from municipal wastes (see ‘historic
landfilling’ above); and
○○ Fuel stations – these may have been associated with releases from
underground fuel tanks.
A number of electricity substations are also likely to be present. Industrial
estates may, over time, be impacted by a range of potentially contaminative
activities. Older electricity substations may be associated with polychlorinated
biphenyl contamination. A substantial gas works site (Hilsea Gas Works)
was also present 850m to the west of Flood Cell 4 prior to 2006. Gas
works sites are most commonly associated with TPH (including benzene),
PAH, metals and inorganic cyanides.
●● Military Sites – Portsea Island has a military presence stretching back
several centuries. Over the years defence embankments, batteries and
fortifications have been constructed with barracks, rifle ranges, training
centres and depots some of which were also associated with areas of
landfilling (see above). Military sites can, depending on their precise
uses, be associated with contaminants such as fuels and lubricating
oils from vehicles and machinery, heavy metals and asbestos from
plant, buildings and munitions, solvents and a wide range of chemicals
from manufacturing and maintenance activities. Radioactive sources
may also have been used or stored on these sites, for example
luminous dials used in aircraft.
●● Hospitals – Hospital sites may be associated with a number of potential
contaminants or sources of contamination, include radioisotopes,
asbestos from demolished buildings and areas of landfilling.
●● Sewage Works – As a result of leaks or spills from equipment and
pipework, sewage works may become a source of contaminants such
as heavy metals, nutrients and pathogens.
●● Cemetery – Cemeteries may be sources of contamination, such as
metals, nutrients and pathogens and are also sites which may be
associated with ground gases are potentially highly sensitive to
changes in groundwater level.
●● Made Ground (including embankments and potentially infilled gravel or
clay pits) – PCC records indicate extensive areas of ‘waste disposal
and unknown infill’ within or close to the study area. It is likely that there
are some extensive deposits of Made Ground within the study area in
addition to the identified areas of landfilling. Some fill may have been
derived from estuarine sediments dredged from the harbour channel.
However, as the origin of the fill is often not known, it may also have
come from industrial sites and be associated with a range of contaminants.
10.1.2 Potential Pathways
The precise nature and location of flood management works which will be
implemented as part of the Schemes have not yet been established.
However, as outlined in section 3.1, elements of work may include raising
or replacing walls and measures for retaining beach material. Technical
Report 6: Surveys gives initial indications of possible foundation types and
engineering solutions including sheet piled walls, gravity structures, earth
embankments and Groynes. In the north of Flood Cell 4, indications are
that any piled foundations would be founded in the Upper Chalk. The
Schemes have also not ruled out the need for temporary storage of water,
either saline water from overtopping or rainwater retained until the tide
falls sufficiently for it to be discharged to sea.
A number of migration pathways may therefore be present currently or as a
result of any of the Schemes, which may aid the migration of contamination
either to the site from adjacent land or from the site towards sensitive
receptors. These include:
●● Permeable ground – Groundwater vulnerability information indicates
that the study area is underlain by high permeability soils with limited
capacity to attenuate pollutants. Where present, Made Ground may
also be permeable. The review of site geology indicates that large parts
of the site are underlain by superficial deposits which are classed as
Secondary Aquifers. These deposits may allow the migration of mobile
contaminants including ground gases.
●● Groundwater – The aquifers beneath the study area (both the
superficial Secondary Aquifers and the Bedrock Secondary and
Principal Aquifers) may hold quantities of groundwater which may allow
the migration of contaminants.
●● Surface water – Several lakes/ponds, ditches and moats were
identified in, or close to, the study area. In addition, the flood cells
boarder Portsmouth, Chichester and Langstone Harbours and the
Solent. Where overland flow occurs, surface waters may rapidly
transmit contaminants deposited at the ground surface. Additionally,
where surface water flooding occurs (for example due to overtopping or
planned temporary storage of water), contaminants may be
redistributed across the land surface. Surface water and groundwater
may be in hydraulic continuity in the study site and surrounding area
where permeable strata are present.
●● Erosion – Where landfill sites or other areas of contaminated soil lie
adjacent to the coast, erosion of the waste/soils may allow
contamination to enter the water environment. Infiltration of seawater
into the waste/soil may also mobilise contamination and allow this to
leach out into the water environment.
●● Direct contact – Ingestion or dermal contact may occur where
contaminants are present at or near the surface or are exposed as a
result of construction activities. Ingestion may include consumption of
home grown vegetables in areas of residential or allotment land use.
●● Inhalation – From airborne particles, ground gases and vapours that
may be present on site and/or mobilised by construction activities.
●● Drains / underground utilities – Contaminants may be transported onto
or off the site through surface water drains, field drains, sewers or other
underground service conduits.
●● Contact with underground structures – Direct contact of contaminants to
buildings/ construction where foundations are laid in contaminated soils.
10.1.3 Potential Receptors
Receptors which may be significantly harmed or polluted by contaminative
materials (if present) are considered to be:
●● Human health (Future users of the site – residents, visitors,
trespassers, neighbours) – it is understood that land use within the
study area will remain the same i.e. domestic, commercial, industry and
amenity uses.
●● Human health (Contractors and construction workers) – construction
workers may be required to work close to potentially contaminated soils
and water, although it is recognised that there may be limited exposure
due to the short-term nature of the proposed earthworks activity. Short
term risks may be mitigated by the use of appropriate personal protective
equipment (PPE) and health and safety regulations but will require
further assessment by the contractor (this is discussed in Table 10.1).
●● Groundwater – Shallow groundwater may be present in the vicinity of
the site within the Secondary and Principal Aquifers. No Environment
Agency licensed groundwater abstractions have been identified on the
site; however additional private water abstractions may exist in the
vicinity of the study area.
●● Surface water – Several lakes/ponds, ditches and moats were
identified in, or close to, the study area which could be impacted by
mobile contamination. In addition, the flood cells boarder Portsmouth,
Chichester and Langstone Harbours and the Solent, which are
ecologically designated sites.
●● Ecological receptors – The flood cells boarder Portsmouth, Chichester
and Langstone harbours and the Solent, all of which are designated for
ecological sensitivity .
●● Buildings and Structures – Some contaminants such as hydrocarbons
and sulphates, if present, may be deleterious to building materials used
in below ground structure, for example concrete piled foundations.
Structures including confined spaces may also be susceptible to the
accumulation of ground gases.
10.2 Summary of Pollutant Linkages and Preliminary Qualitative Risk
Assessment
10.2.1 Methodology
The preliminary qualitative assessment is based on guidance presented in
CIRIA C552 ‘Contaminated Land Risk Assessment’, London 2001. The
process involves the classification of the following:
●● The magnitude of the potential consequence, which takes into account
both the potential severity of the hazard and the sensitivity of the
receptor;
●● The magnitude of the probability (likelihood) which takes into account
both the presence of the hazard and the receptor and the integrity of
the pathway.
The resultant risk categories are shown in Table 10.1 and 10.2.
Table 10.1: Contamination Risk Categories
Probability
Consequence
Severe
Medium
Mild
Minor
High
Likelihood
Very High Risk
High Risk
Moderate Risk
Moderate /
Low Risk
Likely
High Risk
Moderate Risk
Moderate /
Low Risk
Low Risk
Low
Likelihood
Moderate Risk
Moderate /
Low Risk
Low Risk
Very Low Risk
Unlikely
Moderate /
Low Risk
Low Risk
Very Low Risk
Very Low Risk
Table 10.2: Definition of Risk Categories
Risk Category
Definition
Very High Risk
There is a high probability that severe harm could arise to a
designated receptor from an identified hazard or there is evidence
that severe harm to a designated receptor is currently happening.
The risk, if realised is likely to result in a substantial liability. Urgent
investigation (if not undertaken already) and remediation are likely
to be required
High Risk
Harm is likely to arise to a designated receptor from an identified
hazard. Realisation of the risk is likely to present a substantial
liability. Urgent investigation (if not undertaken already) is required
and remedial works may be necessary in the short term and are
likely over the longer term
Moderate Risk
It is possible that, harm could arise to a designated receptor from
an identified hazard. However it is either relatively unlikely that
any such harm would be severe, or if any harm were to occur, it is
more likely that the harm would be relatively mild. Investigation (if
not already undertaken) is normally required to clarify the risk and
to determine the potential liability. Some remedial works may be
required in the longer term
Low Risk
It is possible that harm could arise to a designated receptor from
an identified hazard but it is likely that at worst this harm if realised
would at worst normally be mild
Very Low Risk
There is a low probability that harm could arise to a receptor, in the
event of such being realised it is not likely to be severe
10.2.2 Assessment
Through the review of historic and current environmental information, and
the development of the conceptual site model (source, pathway and
receptor contaminant linkage model) a number of potential pollutant
linkages may be present. The following tables (Tables 10.3 and 10.5)
provide further assessment of these potential linkages.
This preliminary risk assessment has been undertaken at the scoping
stage of the Schemes. Information has been brought together from a
range of data sources which has identified the potential for contamination
across significant parts of the study area. Details of the Schemes’ design
are not yet available and hence the following risk assessment has been
undertaken at the Flood Cell scale, with risks identified at a high level. It is
strongly recommended that, in close conjunction with the development of
engineering options, these risks are considered further and both the
conceptual site model and the preliminary risk assessment refined as the
Schemes’ progress. The information provided in this report, particularly
Sections 6 to 9 and Annex 3 should be reviewed, supplemented and
updated as further information becomes available. This is in accordance
with the process detailed in CLR11 (Figure 1, Annex 2).
able 10.3: Summary of Potential Pollutant Linkages and Preliminary Risk
T
Assessment: Flood Cell 1 – Southsea
Receptor
Likely Risk
Level
Human Health
(Future Site Users /
Land Owners)
Moderate
Land use in Flood Cell 1 is predominantly
residential and public open space, with some
industrial and commercial sites. Risks may
already exist from site users coming into contact
with contaminated soil/water. Without mitigation,
earthworks and structures introduced as part of
the scheme may provide additional pathways
for exposure to contamination by bringing
contaminated soils to the surface or influencing
shallow groundwater levels
Moderate
Significant areas of historic potential infilling
have been identified in Flood Cell 1, together
with a number of historical industrial land uses.
Some sites already have remediation reports
associated with them; however the extent of that
remediation is unknown (whether this extends to
removal of all contaminated material, treatment
of any deeper contamination or was restricted to
treatment or covering of shallow contamination).
Construction workers may therefore encounter
significant areas of contaminated soil/water
during the construction period
Moderate
The majority of Flood Cell 1 is underlain by
Secondary A Superficial Aquifers underlain by
Secondary A Bedrock Aquifers. Groundwater
vulnerability is classified as high. Groundwater
is therefore likely to be relatively sensitive to
impacts from contaminated land including
migration of mobile contamination via
preferential pathways such as piled foundations
Human Health
(Contractors /
Construction
Workers)
Groundwater
Surface Waters
High
Ecological
Receptors (i.e fauna
and flora)
Buildings,
Structures and
Construction
Materials
Comment / Linkage
High
Moderate
Flood cell 1 lies adjacent to coastal waters which
are designated for environmental sensitivity.
These are therefore considered to be sensitive
receptors to impacts from contamination via
pathways such as coastal erosion of soils or
wastes and leaching of contamination due to
infiltration of surface water
Underground structures may be affected by
some contaminants such as hydrocarbons and
sulphates. Areas of fill material may have the
potential to generate hazardous gas which may
migrate via permeable strata or preferential
structures such as pipework ducts and
accumulate in confined spaces and / or buildings
Table 10.4: Summary of Potential Pollutant Linkages Flood Cell 2 and
Preliminary Risk Assessment – Fraser Battery/Eastney
Receptor
Likely Risk
Level
Comment / Linkage
Human Health
Land Owners)
Land use in Flood Cell 2 is mixed residential,
public open space, commercial (including a
marina) and industrial, with historic areas of
landfilling and infilling, sewage works and former
military sites. Risks may already exist from site
Moderate/
users coming into contact with contaminated
high in some
soil/water. Without mitigation, earthworks and
areas
structures introduced as part of the scheme may
provide additional pathways for exposure to
contamination by bringing contaminated soils to
the surface or influencing shallow groundwater
levels
Human Health
(Construction
Workers)
Moderate/
high in some
areas
Groundwater
Moderate
Surface Waters
Ecological
and flora)
Buildings,
Structures and
Construction
Materials
High
High
Moderate
The majority of Flood Cell 2 is underlain by
Secondary A Superficial and Bedrock Aquifers.
In the north of the cell, a small area is underlain
by a Superficial Secondary Undifferentiated
Aquifer over the Secondary A Bedrock Aquifer.
Groundwater vulnerability is classified as high.
Groundwater is therefore considered to be of
moderate sensitivity
Flood Cell 2 lies adjacent to coastal waters which
infiltration of surface water
some contaminants such as hydrocarbons and
sulphates. Areas of fill material may have the
potential to generate hazardous gas which may
migrate via permeable strata or preferential
structures such as pipework ducts and
accumulate in confined spaces and / or buildings
able 10.5: Summary of Potential Pollutant Linkages Flood Cell 4 and
T
Preliminary Risk Assessment – North Portsea Island
Receptor
Likely Risk
Level
Human Health
Land Owners)
Moderate
Land use in the Flood Cell is predominantly
public open space, incorporating significant
areas of former landfill or other infilling,
together with a number of industrial and
commercial sites. The industrial sites include
the former aerodrome, which once included
aero-engineering facilities, hospitals, wharves,
factories depots and, inland of the Flood Cell,
a former gas works site. Risks may already
exist from site users coming into contact with
contaminated soil/water. Without mitigation,
earthworks and structures introduced as part of
the scheme may provide additional pathways
for exposure to contamination by bringing
contaminated soils to the surface or influencing
shallow groundwater levels
Moderate
Human Health
(Construction
Workers)
Groundwater
Comment / Linkage
The north of Flood Cell 4 is underlain by a
Principal Bedrock Aquifer (the Upper Chalk)
Low
(unproductive which is overlain predominantly by a Secondary
Undifferentiated Superficial Aquifer. Groundwater
strata)
vulnerability is classified as high. Groundwater is
therefore likely to be more sensitive to impacts
from contaminated land (including migration of
Moderate
mobile contamination via preferential pathways
(Secondary such as piled foundations) than in other parts
Aquifers)
of the study area. Further south, along the
east coast of Portsea Island, Flood Cell 4 is
underlain by a Secondary A Bedrock Aquifer
(moderate sensitivity) or unproductive strata (low
High
sensitivity), with a Secondary Undifferentiated
(Principal
Superficial Aquifer overlying these. Groundwater
Aquifer)
is therefore likely to be less sensitive to impacts
from contaminated land in these areas
Receptor
Likely Risk
Level
Surface Waters
High
Ecological
and flora)
Buildings,
Structures and
Construction
Materials
High
Moderate
Comment / Linkage
Flood Cell 4 lies adjacent to coastal waters which
infiltration of surface water. Visual evidence from
the site walkover indicated that this pathway
might currently be active in some places
(indications were noted of leachate potentially
seeping through the existing sea wall).
some contaminants such as hydrocarbons
and sulphates. Areas of fill material may
have the potential to generate hazardous gas
which may migrate via permeable strata or
preferential structures such as pipework ducts
and accumulate in confined spaces and / or
buildings. Extensive areas of fill have been
identified within this Flood Cell
11 CONCLUSIONS AND RECOMMENDATIONS
11.1 Conclusions
A desk-based assessment of contamination risks has been undertaken for
the Scoping Stage of the proposed Schemes. The Schemes have been
divided into three Flood Cells and a number of potential sources of
contamination have been identified both within and near each Flood Cell.
These include extensive areas of historic landfilling and infilling.
Within each Flood Cell, land use is mixed, with residential, commercial and
industrial premises and public open space. Each of the Flood Cells borders
coastal waters which are designated for environmental sensitivity and are
therefore a sensitive receptor to contaminated material eroded from the
coastal frontage or leached from contaminated land by infiltrated water.
Risks to groundwater receptors are likely to be higher in the north of Flood
Cell 4, which is underlain by the Chalk Principal Bedrock Aquifer (the
Upper Chalk), than in the remainder of the study area. The south eastern
areas of Flood Cell 4 are mainly underlain by unproductive bedrock strata
(London Clay). However, all parts of Flood Cells 1 and 2 are underlain by
Secondary Superficial and Bedrock Aquifers.
Foundations, particularly piled foundations which extend into the aquifers
can act as preferential pathways for the transfer of contamination. Care
will need to be exercised to ensure that appropriate piling methods and
pile types are used and that contamination levels in strata surrounding the
piles is adequately characterised in order to manage these risks to
groundwater quality.
All three Flood Cells have historical and/or current industrial and
potentially contaminative land uses indicating that significant areas of soil
and/or groundwater contamination may exist. Extensive areas of historical
landfilling have been identified in Flood Cells 2 and 4; however significant
areas of historic infilling have also been indicated in Flood Cell 1. Some
sites already have remediation reports associated with them; however the
extent of that remediation is unknown (whether this extends to removal of
all contaminated material, treatment of any deeper contamination or was
restricted to treatment or covering of shallow contamination).
Risks via direct contact may exist already within the Flood Cells, although
remediation reports obtained for some key sites of concern indicate that
capping layers have been introduced in order to limit risks to human
receptors. Risks could be increased by the Schemes’ works if contaminated
material is brought to the surface by excavation or if contaminated
materials are used in the construction of earth flood embankments. Care
will be needed to ensure that only uncontaminated materials are used
where sensitive receptors could come into contact with the soil.
Given the likelihood of contamination and landfilled waste being present at
the coastal frontage, risked posed by these areas as a result of erosion
and inundation (e.g. by wave overtopping and/or flood storage) are likely
to be significant.
Based on the information reviewed, it is considered that soils at the site
may contain significant levels of contamination, including deeper soils
beneath remedial capping layers. The risk from contamination has been
assessed as:
●● Medium for human health receptors;
●● High for surface water ecological receptors;
●● Low to high for groundwater receptors, depending on the classification
of the aquifers.
Care will need to be taken throughout the design, construction and
operational phases of the Schemes to ensure that sensitive receptors are
protected and that excavated materials are suitable for re-use.
A conservative approach has been applied to the preliminary risk
assessment due to current uncertainties concerning the location and
design of the works associated with the Schemes and the presence of a
large number of potential sources of contamination. The risk levels may
be able to be reduced significantly by more detailed characterisation of
individual locations of flood defence works and as a result of knowledge of
the Schemes’ detailed design.
11.2 Recommendations
Recommendations for managing risks associated with land quality and
materials management are presented below, with additional detail
provided in Table 11.1.
This preliminary risk assessment has been undertaken at the scoping
stage of the Schemes. Information has been brought together from a
range of data sources which has identified the potential for contamination
across significant parts of the study area. Details of the Schemes’ design
are not yet available and hence the following risk assessment has been
undertaken at the Flood Cell scale, with risks identified at a high level. It is
strongly recommended that, in close conjunction with the development of
engineering options, these risks are considered further and both the
conceptual site model and the preliminary risk assessment refined as the
Schemes progress. The information provided in this report, particularly
Sections 6 to 9 and Annex 3 should be reviewed, supplemented and
updated as further information becomes available. This is in accordance
with the process detailed in CLR11 (Figure 1, Annex 2).
As discussed in Section 3.1, it is intended that the assessment contained
in this report should provide the starting point of an ongoing assessment
process and that the relevance of land contamination issues to the
Schemes should be further assessed in conjunction with the development
of the Schemes engineering options and design. Depending on the level
of risk identified, the steps of this process may include some or all of the
following:
●● Refining of the conceptual model;
●● Intrusive Site Investigation;
●● Quantitative Risk Assessment;
●● Remediation;
●● Controls during construction including materials management controls.
It is not possible to determine next steps on a site-specific basis until the
outline design stage. As part of this assessment general recommendations
have been made on likely next steps.
In particular, elements of further work have been highlighted throughout
this report which should be undertaken as the design is progressed.
These include:
●● Review of the smaller scale historical maps (1:2,500 and 1:1250 scale)
which may provide additional information on site history for specific areas
of concern. These have been provided as part of the Envirocheck®
reports for the flood cells. PCC Contaminated Land team should be
consulted to establish if such a review has already been undertaken.
●● Review all remaining available reports held within the PCC contaminated
land archive for specific areas of concern. Further intrusive site
investigation is likely to be needed for areas of concern since some of
the reports reviewed are a number of years old and site conditions may
since have changed. Other reports reviewed were focused on particular
pathways or particular areas of the site and hence may not provide all
the information necessary for the assessment of the Schemes.
●● In considering the potential contaminants associated with each land
use, reference should be made to publications including the former
Department of Environment Industry Profiles.
●● Obtaining and review of private water supply information available from
the Local Planning Authority records.
●● Review of underground utilities information to establish whether
preferential pathways or sensitive utilities may be affected by the Schemes.
●● Assessment of risks from radon on any confined spaces.
●● A specification for ground investigation should be produced once the
desk based investigations have been completed (bullet points 1 to 3
above) and sufficient design information is available concerning where
the construction works will take place and the nature of the works.
This will enable expenditure on ground investigation to be focused on
particular areas of concern and/or risk to the Schemes.
Table 11.1: Recommendations
Aspect of
Schemes
Concern
Recommendation
Potential costs and benefits to
the Schemes
Potential
for areas of
contamination
to be present
Protection of
sensitive receptors
●● Undertake further focused desk based
assessment once the preferred option has
been developed and the footprint of the
proposed works is more defined with the
objective of refining the initial Conceptual
Site Model presented in this report
-- The cost of ground investigation,
soil and water analysis and
production of assessments
and reports can be significant,
but can be minimised by
investigating only those areas
identified by the outline design as
being affected by the Schemes.
This may include the footprint
of excavation works, any areas
where land use will change and
any areas where surface water
will be stored or the groundwater/
infiltration regime will be altered
by the Schemes
●● Based on this focused study, appropriate
contamination testing, focused on areas to
be excavated and, if necessary, any areas
where material will be placed on site. This
should be combined, where possible, with
geotechnical ground investigation in order
to achieve cost efficiencies
●● Completion of a Land Quality interpretative
assessment (risk assessment) for all
appropriate sensitive receptors
++ Site investigation will allow
any necessary remediation or
mitigation to be developed and,
if possible, integrated into the
Schemes design to maximise
cost efficiency
Note that, if samples are required
from the intertidal zone, a marine
licence would be required from the
Marine Management Organisation
and consent from Natural
England for work in any European
designated sites. These works
may require an EIA, Appropriate
Assessment, and potentially Water
Framework Directive Assessment,
which could constrain or impact on
the project programme and cost.
Materials
Reuse
●● Use results of the Land Quality
Compliance with
interpretative assessment (see above)
the CL :AIRE Code
to complete Materials Management Plan
of Practice entitled
(MMP). This should be completed prior to
‘The definition of
soils being reused or removed from the site
waste: Development
Industry Code of
●● Complete Site Waste Management Plan
Practice’ for any
(SWMP) if required. This should be started
materials reused onduring the design phase, refined and
site or intended to
completed prior to the construction phase
be used on another
site via ‘direct
transfer’
-- Costs for production of the MMP
and SWMP
++ Benefits in avoiding the disposal
costs for material which is
suitable for reuse within the
Schemes; minimising costs for
purchasing and importing of soils
needed for the Schemes; and
avoiding (wherever possible) the
costs/time involved in applying
for Environmental Permits or
Exemptions
Aspect of
Schemes
Concern
Recommendation
the Schemes
Disposal of
unsuitable
materials and
importation of
clean fill
Compliance with
waste management
legislation including
the Landfill
Regulations 2002
(as amended) and
the Hazardous
Waste Regulations
2005
Characterisation (prior to disposal)
and disposal off-site of any materials
demonstrated not to be suitable for reuse
-- Possible costs for completion
of waste characterisation if any
soil arisings are proven to be
unsuitable for reuse
Pre-treatment prior to disposal to either
reduce the volume of hazardous waste
requiring disposal or to reduce the hazardous
nature of the material
Disposal of wastes in accordance with the
waste hierarchy
Testing and verification of any soils imported
to the site to ensure that they do not pose
an unacceptable risk to human health or
controlled waters (prior to importation). They
will also need to be accompanied by all
relevant Duty of Care documentation
Control of
groundwater
Best practice for
construction site
management.
Avoidance of
pollution incidents
++ Benefits of managing potential
risks and compliance with
legislation
-- Costs –disposal costs of
unusable waste (possibly
including landfill tax and gate
fees if no other disposal route is
found)
If dewatering of excavations is undertaken as
part of the proposed Schemes these should
be contained and disposed of appropriately
to ensure that sediment and/or contaminated
water is not discharged to water
-- Possible costs to supply
containment of groundwater and
obtain consent to discharge to
foul sewer or for appropriate offsite disposal
Best practice guidance should be followed
(for example, Pollution Prevention Guidance
Note (PPG) 5: Works and maintenance
in or near water and PPG6: Working at
construction and demolition sites)
++ Benefits of managing potential
risks and compliance with
legislation
Preparation of a method statement prior to
construction, identifying the procedures to
be followed should previously unidentified
contamination be encountered. This should
include seeking professional advice from a
suitably qualified environmental consultant
Aspect of
Schemes
Concern
Recommendation
the Schemes
Construction
Phase Health
and Safety
- potential
exposure of
construction
workers to
contaminants
in soil or
water
Compliance with
Health and Safety
Legislation including
the Health and
Safety at Work
Act 1974 and
Construction Design
& Management)
Regulations 2007
Good site practice and hygiene in addition to
the use of appropriate Personal Protective
Equipment (PPE) and Respiratory Protective
Equipment (RPE), where necessary
-- Costs for provision of PPE, RPE
if necessary and for production
of method statements and risk
assessments
Method statements and risk assessments
should be developed prior to construction for
all site works to aid identification of such risks
and appropriate risk avoidance and reduction
measures. The works should be undertaken
in accordance with the requirements of
the Construction (Design & Management)
Regulations 2007 where appropriate
++ Benefits of managing risks and
compliance with legislation;
-- Costs for specialist contractors
/ appropriate training etc (e.g.
Asbestos removal)
Should any work be undertaken in confined
spaces on the site, an appropriate risk
assessment should be undertaken and
appropriate PPE used. Particularly as logs
indicate that made ground or peaty layers
may be present in alluvial deposits and
reports indicate historic landfill containing
domestic and unknown wastes may be
present.
Specification
of materials
for below
ground
structures
Impact of
aggressive ground
conditions
Soil and water sampling and testing may be
required to characterise ground conditions
where underground structures are planned
to enable suitable materials to be specified.
This should be undertaken once the footprint
of the proposed works is more defined and
the design of the works has been further
progressed.
Where sensitive underground utilities are to
be introduced or moved as a result of the
Schemes (e.g. potable water supply pipes)
the utility provider should be contacted in
order to agree a suitable specification
++ Protection of human health
and integrity of below ground
structures
-- Cost of sampling and analysis of
soils
-- Possible cost of material disposal
if excess material is unable to be
reused.
12 BIBLIOGRAPHY
British Geological Survey (BGS) Map of Portsmouth 1:50,000 series, Sheet 331
(Solid and Drift Edition).
British Geological Survey (BGS) Map of Fareham 1:50,000 series, Sheet 316
(Solid and Drift Edition).
CIRIA, 2005 Environmental Good Practice on site (second edition), London
CL:AIRE (2008). The Definition of Waste: Development Industry Code of
Practice.
Clayton Environmental Consultants Limited (1995) Ground Investigation,
Tangier Road Portsmouth.
Environment Agency website: http://maps.environment-agency.gov.uk/wiyby
Environment Agency (2000) Pollution Prevention Guidelines. Works in, near or
liable to affect watercourses: PPG5 and Pollution Prevention Guidelines. Works
in, near or liable to affect watercourses: PPG5.
Environment Agency (2004) Contaminated Land Report 11 (CLR11): Model
Procedures for the Management of Land Contamination
ERM (2009) H&S Aviation, Portsmouth, Human Health Generic Quantitative
Risk Assessment
ESI (2010). Canoe Lake Contaminated Land Investigation: Detailed Inspection
and Assessment of Canoe Lake, Portsmouth.
Halcrow Group Limited (2004) Portsea Island Coastal Strategy Study:
Contamination Risk Assessment Report
Hyder Consulting (2000) Eastney Married Quarters, Portsmouth: Method
Statement in Support of Planning Application.
Leigh Analytical Services (1994) Horsea Allotment Ground Investigation
Parkman Buck Limited (1993) Alexandra Park, Portsmouth Contaminated Land
Site Investigation Report
Parkman Buck Ltd (1993) The Glory Hole Eastney Quantified Risk Assessment
for the Glory Hole Eastney Vol 1 & 2.
Parkman Buck Limited (1993) Tipner Quay, Twyford Avenue, Desk Study
PCC and Wimpey Homes Holdings Limited (1997) Agreement in Pursuance
of Section 106 of the Town and Country Planning Act 1990 and Section 111 of
the Local Government Act 1972 relating to Former HMS Phoenix Site Matapan
Road Stamshaw Portsmouth.
Soils Limited (2007) Report on a Ground Investigation on Kendalls Wharf,
Eastern Road, Portsmouth.
Annex 1: Report Limitations
LIMITATIONS
The direct assessments and judgements given in this report are limited by
both the finite data on which they are based and the proposed works to which
they are addressed. The acquisition of data is constrained by both physical
and economic factors and, by definition, is subject to limitations. Conditions at
the site will change over time due to natural variations and may be affected by
human activities.
This document has been prepared for the titled project and should not be relied
upon or used for any other project. Royal Haskoning accepts no responsibility
or liability for the consequences of this document being used for a purpose
other than that purpose for which it was commissioned. The assessments and
judgements contained herein should not be relied upon as legal opinion.
The findings and opinions are relevant to the dates of the information reviewed
and should not be relied upon to represent conditions at later dates. The
opinions included herein are based on the information obtained from the
assessments undertaken in the study area and from the experience of the
reviewers.
This Phase I Land Quality Assessment has utilised a variety of publicly available
data sources such as the Environment Agency, Landmark Group, historical
maps and the British Geological Survey. Therefore, the study is limited by the
age and limitations inherent in the data described.
Annex 2: Figures
Annex 3: Envirocheck Report
Annex 4: Outputs from the PCC Contaminated Land Archive Search

southsea and north portsea island coastal flood and erosion risk

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