Phase I Geo-Environmental Desk Study

Rear of The Deri Dobbs Weir Road Roydon Essex EN11 0BQ

Prepared for:

Mr D Barthram c/o Sole Concepts Ltd Architectural & Structural Services Unit 3 Haslemere Estate Charlton Mead Lane Hoddesdon Hertfordshire EN11 0DJ

EPS Project Reference: UK18.4199

Date Issued: 29th October 2018

Report Status: Issue 1 Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

REAR OF THE DERI, DOBBS WEIR ROAD, ROYDON

NON TECHNICAL CLIENT SUMMARY This report presents the findings of a Phase I Geo-Environmental Desk Study which was carried out to identify potential contamination from previous or current uses of the site and surrounding area and to provide an initial assessment of geological and geotechnical aspects of the site and how the proposed development or surrounding environment might be affected.

• The site is located in Dobbs Weir approximately 1.75km east of Hoddesdon and is comprised of what used to be the garden areas of several properties, with a caravan and soil mound presently on site. • Ground conditions from a previous historic borehole are reported to comprise superficial deposits of Alluvium (predominantly sands and gravels) to a depth of roughly 9-10m, underlain by chalk. The Alluvium is classified as a Secondary Aquifer and the bedrock as a Principal Aquifer. • Historic mapping for the area and records provided by Epping Forest District Council indicate that the site has been developed since 1939 as several residential garden areas with it only recently having been amalgamated into one area. Correspondence with Epping Forest District Council indicates that these areas have previously been developed for small residential garage structures. Historically within the surrounding areas there have been several gravel pits which have historically or are presently being infilled. There have also been nurseries previously sited adjacent to the south and east of the site with the former replaced with a residential property in 2002. • A number of potential contamination risks have been identified due to the possible presence of made ground at the site and the presence of historic and current landfills in the area. It is therefore recommended that these risks be further investigated by means of an exploratory investigation. • A copy of this report should be provided to the Environmental Health department of Epping Forest District Council so that the information may be used to support planning proposals for the site.

By their very nature, the above bullet points represent a simplified summary of our work and should not be relied upon to form the basis for key decisions for the proposed development. A full picture is provided in the following report, or alternatively give us a call and we’ll talk you through it.

Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

Project Reference: UK18.4199 Phase I Geo–Environmental Desk Study Title: Rear of the Deri, Dobbs Weir Road, Roydon Client: Mr D Barthram c/o Sole Concepts Ltd

Date: 29th October 2018

7B Caxton House T: 01954 710666 Broad Street F: 01954 710677 EPS Contact Details: Cambourne E: [email protected] Cambridge CB23 6JN W: www.epstrategies.co.uk

Status: Issue 1

Author: Reviewed: Authorised:

Daryl Bowell Michael Judson Steve Bullock Consultant Senior Consultant Director

This report has been prepared for the client(s) listed on the report title page. EPS accepts no liability or responsibility for use of, or reliance upon, this report and / or the information contained within it by third parties.

If third parties have been contracted / consulted during compilation of this report, the validity of any data they may have supplied, and which are included in the report, have been assessed as far as possible by EPS however, EPS cannot guarantee the validity of these data.

Where ground investigations have been conducted, these have been limited to the level of detail required for the site in order to achieve the objectives of the investigation.

No part of this report, or references to it, may be included in published documents of any kind without approval from EPS. This report and its contents, together with any supporting correspondence or other documentation, remain the property of Environmental Protection Strategies Ltd until paid for in full.

The report has been written, reviewed and authorised by the persons listed above. It has also undergone EPS’ in house quality management inspection. Should you require any further assistance regarding the information provided within the report, please do not hesitate to contact us.

The National Planning Policy Framework requires a competent person to prepare site investigation information, which is defined as a person with a recognised relevant qualification, sufficient experience in dealing with the type(s) of pollution or land instability, and membership of a relevant professional organisation. EPS considers that it fulfils these criteria and would welcome any request for staff CVs or case studies to demonstrate it.

As stated within DEFRA’s Contaminated Land Statutory Guidance, with any complex risk assessment it is possible that different suitably qualified people may reach slightly different conclusions when interpreting the same information. EPS recognises this and considers the conclusions presented within this report to be robust and appropriate but input from the Local Authority and their judgement in line with this guidance would still be welcomed.

Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

TABLE OF CONTENTS

1 INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 Objectives ...... 1 1.3 Project Limitations and Constraints ...... 2 2 GEO-ENVIRONMENTAL SETTING ...... 3 2.1 Site Location and Description ...... 3 2.2 Environmental Setting ...... 4 2.3 Landfill & Waste ...... 5 2.4 Industrial Land Use & Pollution...... 5 2.5 Sensitive Land Use ...... 5 2.6 Epping Forest District Council ...... 6 2.7 Unexploded Ordnance (UXO) Risk ...... 7 2.8 Site History ...... 7 3 CONCEPTUAL MODEL AND PRELIMINARY RISK ASSESSMENT ...... 9 3.1 Source Characterisation ...... 9 3.2 Potential Receptors ...... 9 3.3 Potential Pathways ...... 10 3.4 Summary of Contaminant Linkages ...... 11 4 GEOTECHNICAL GROUND MODEL ...... 14 5 CONCLUSIONS & RECOMMENDATIONS ...... 16

Figures

Figure 1 Site Location Plan Figure 2 Current Site Layout Figure 3 Aerial Photograph

Appendices

Appendix A Site Walkover Notes and Selected Site Photographs Appendix B Proposed Development Plan Appendix C Surrounding Land Use Appendix D Geological Context Appendix E Groundwater Vulnerability Maps Appendix F EFDC Environmental Information Regulations Response Appendix G EFDC GIS Mapping Appendix H A Selection of Historic Maps

Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

1 INTRODUCTION

In September 2018, Environmental Protection Strategies Ltd (EPS) was commissioned by Sole Concepts Ltd on behalf of Mr D Barthram to complete a Phase I Geo-Environmental Desk Study on land rear of the Deri, Dobbs Weir Road, Roydon, Essex, EN11 0BQ (‘the site’); see Figure 1.

The work was commissioned in order to fulfil planning requirements for three residential properties with associated parking and garden areas under Epping Forest District Council’s planning reference EPF/2213-18.

This report presents the findings, conclusions, and recommendations of the Phase I Desk Study undertaken for the site as instructed.

1.1 Background

A Desk Study comprises the first stage of any geo-environmental assessment, the purpose of which is to determine what potentially contaminative activities may have occurred at the property or the surrounding area which may pose an environmental or geological risk to site users, the surrounding environment or proposed development, either at present or in the future.

The method used in this investigation to assess the environmental risk posed is based on the concept of ‘contaminant linkage’, which considers the following three factors:

The location from which an environmentally hazardous / contaminative Source substance is, (or was,) derived. An environmentally sensitive object or condition e.g. person, property, Receptor controlled water, or ecological system, which may be present now or in future. A route or mechanism via which a source could come into contact with a Pathway receptor to cause significant harm.

If all three factors are identified, there is the potential for a ‘contaminant linkage’ to be active, which could result in significant harm being caused to the environment or human health.

1.2 Objectives

The purpose of this desk study is to evaluate the potential contaminant linkages which may be active at the site in its current condition, or could become active in future, and to determine if any action is required to investigate them further or to break them.

This is achieved by carrying out the following activities:

a) Examining the site history - late 1800s to present day, through collection of historical maps of the area, site records, records held by relevant local authorities, the Environment Agency and review of other information databases. b) Characterising the site’s environmental and geological sensitivity through examination of existing geological, hydrogeological, topographical, and historical maps and aerial photographs of the area. c) Identifying Potential Areas of Concern (PAOCs) through a combination of historical map and data review and site inspection.

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d) Consideration of any future plans for the site and the effects any proposed changes may have on contaminant linkages over time. e) Development of a site conceptual model and preliminary risk assessment to determine the potential risks posed by the site and make recommendations for any further work that may be required and to ensure suitability for use and safe development in accordance with the Model Procedures for the Management of Land Contamination - Contaminated Land Report 11 and the National Planning Policy Framework.

1.3 Project Limitations and Constraints

The purpose of this report is to present the findings of a Phase I Geo-Environmental Desk Study conducted at the location(s) specified. When examining the data collected from the investigations made during the assessment, EPS makes the following statements:

This report does not include specific investigation for the presence of either Potential Asbestos Containing Material (PACM) or Japanese Knotweed at the subject site however, if obvious evidence of either is observed during EPS site walkover, details will be provided in this report. Specialist contractors should be commissioned to make detailed assessments and recommendations if these materials are suspected.

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2 GEO-ENVIRONMENTAL SETTING

The following section provides a summary of the information collected in relation to the site location and history.

2.1 Site Location and Description

Detail Description The site is located in Dobbs Weir, an area of Roydon approximately 1.75km Location southeast of Hoddesdon town centre. Grid 538831, 208020 Reference Topographic The site sits at approximately between 27m above ordnance datum (AOD). Elevation Topographic Levels are generally flat. Gradient A walkover was completed on the 2nd October 2018 and the site was noted to be roughly rectangular in shape covering an area of approximately 0.05 hectares. Access could be gained directly from Derby Road however the site was sectioned off with herras fencing.

The site was found to be currently occupied, with a static caravan along the northern boundary. The area surrounding this was noted to have been levelled with road planings to create a drive area to the front. A single one storey garage occupied the centre of the site and appeared to be being used for the storage of general household items and building supplies. Anecdotal evidence from the client suggests that this used to belong to one of the residential houses that border the site to the north and the site consists of an Description amalgamation of several properties’ previous garden/drive areas. This was of Site further evidenced by the presence of a concrete slab in front (to the south) of the garage and in front of Derby Road with two concrete tracks leading between the two. The concrete on the site was noted to be in good condition and the area between the two slabs was overgrown with weeds through a made ground surfacing.

The area to the rear (east) of the site was densely overgrown and occupied with a spoil mound, the client maintained that this material had originated on site and had been removed for the levelling of the current drive/caravan area. Containers and other discarded material were noted to lie along the southern boundary although there was no evidence of chemical or fuel storage. The entirety of the site was noted to be bounded with timber fencing. The site is surrounded by residential housing in each direction. Further afield Surrounding to the north, is a large area of open land while to the south lies a large lake, Land Use Nazeing Mead.

A plan showing the site location is provided as Figure 1, the current site layout is detailed on Figure 2 and an aerial photograph is included as Figure 3. Selected site photographs and walkover notes are included as Appendix A, an indicative proposed development plan as Appendix B and relevant extracts of a Groundsure report as Appendix C.

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2.2 Environmental Setting

Detail Description Geological maps of the area indicate the site to be underlain by superficial Alluvium deposits (clay, silt, sand & gravel) above bedrock of the Lambeth Geology Group (clay, silt & sand), although Lewes Nodular Chalk is shown nearby in the surrounding area. Information on the site’s geological context is included as Appendix D. A previous historic borehole log was supplied by the client for a location drilled on site in 2014 and reports a thin layer of made ground above clay to 1.45m bgl. Sand and gravel deposits then extend to 9.2m bgl, below Historic which lies chalk to the base of the borehole at 15.0m bgl (below ground Borehole Log level). Groundwater was encountered at a depth of approximately 1.45m bgl rising rapidly to 0.5m. A copy of the historic borehole log is included within Appendix D. Hazard On Site Risk Mining No Hazard Collapsible Ground No Hazard Compressible Ground Moderate Geological Ground Dissolution No Hazard Hazards Running Sand Low Landslide Very Low Shrinking / Swelling Clay Moderate Radon No Hazard The BGS and Health Protection Agency (HPA) report entitled ‘Indicative Atlas of Radon in England and Wales’ (November 2007) shows the site to lie within a 1km grid section where the percentage of homes above the radon Radon action level is between 1% and 3%. The joint Building Research Establishment Ltd (BRE) report entitled: ‘Radon: Guidance on Protective Measures for New Buildings - 2007’ reports that the site does not lie within an area where basic radon protection methods will need to be employed. Groundwater vulnerability maps for the area show that the superficial alluvium and bedrock Lambeth Group are both classified as a Secondary A Aquifer. The site does not lie within a Source Protection Zone for local groundwater abstraction. However a zone 3 (total catchment) of a nearby SPZ does lie roughly 12m to the west. Groundwater vulnerability maps Hydrogeology are included as Appendix E.

The Groundsure report lists two groundwater abstractions within a 500m radius, the closest of which lies 315m away to the south east for horticultural watering.

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Detail Description The nearest surface water feature is the Nazeing Mead lake located 85m away to the southeast.

There are no recorded surface water abstractions within 500m and fourteen recorded discharge consents within the same area, the closest located 35m to the south comprising the release of final/treated effluent sewage.

Review of the EA Flood Zone Map for the area indicates that the site lies within Flood Zone 3, which is defined as the area with a highest potential Hydrology risk of flooding from fluvial or tidal sources. It should be noted that the EA maps do not take in to account the presence of flood defences when designating the flood zones although the areas benefiting from flood defences are shown. They also do not account for flooding from other sources such as poor drainage, or groundwater. Planning policy designates that all sites that lie within Flood Zone 3 require a site specific Flood Risk Assessment to be undertaken prior to the submission of a planning application. It is understood that this is being undertaken by another consultant. A copy of the flood map for the site and surrounding area is also included within Appendix E.

2.3 Landfill & Waste

The EA public database lists five areas of current landfill within 1km, the closest of which lies 182m to the east and is listed as an A05 landfill taking non-biodegradable wastes. There are also thirteen areas of historic landfill within the same radius, the closest of which is listed approximately 40m to the north and appears to have been infilled in 2006 prior to which it was a lake.

There are twelve areas of additional potentially infilled land within a 500m radius, the closest of which is located 96m to the east.

2.4 Industrial Land Use & Pollution

Two sites licensed for industrial activity are listed within the surrounding 500m at 6m and 142m to the south and northwest respectively, listed as Capital Blinds (Curtains and Blinds) and Ace Cars of Hertfordshire Ltd (Vehicle Hire and Rental). There are no fuel station entries within 500m.

One pollution incident to controlled waters is reported 143m to the north east, listed as a category 3 minor incident, involving the release of firefighting run off in 2002.

2.5 Sensitive Land Use

The site lies within a Nitrate Vulnerable Zone where surface water is identified as being at risk from nitrates leaching from agricultural land, whilst an area of Green Belt lies roughly 30m to the north.

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2.6 Epping Forest District Council

Detail Description Information supplied by Epping Forest District Council (EFDC) requested under the Environmental Information Regulations has reported that the site and surrounding land has previously been used as a horticultural nursery, in addition to this the site is reported to be surrounded by areas of landfill with regards to the Environment & Neighbourhood’s response and the Public Health response. No pollution incidents were reported within EFDC 500m of the site. Environmental Information The information confirmed that the site has not been subject to any Regulations investigations or determinations (Under Part 2A of the Environmental Request Protection Act 1990) and the Council has no current plans to investigate the land under this legislation. Council records show that there have been three pollution incidents within the past 10 years in a 500m radius.

The Drainage response indicated no registered private water supplies within 500m. The Environmental Information Regulations Request response is included as Appendix F. A contaminated land screening search was undertaken by EFDC using their GIS database. This search does not indicate the site to have been formerly used for potentially contaminating land use. However, land adjacent to EFDC GIS the east and south have been highlighted to have been used as nurseries Database with the east also hosting livestock and asbestos roofed structures. In addition, an area of open ground approximately 45 metres to the north has been highlighted as being part of an historic landfill.

A copy of the EFDC GIS map and key are also included as Appendix G. Review of publicly available aerial photos show that in 2001 the site was divided into separate plots with an access road running to the rear which grants access to ‘Meadow View’ and ‘The Deri’ from Derby Road. There is a large tree in the garden of ‘The White House’ and the garage noted during the site walkover is on site while a nursery is adjacent to the east of Review of the site. By 2006 the tree to the south of ‘The White House’ has been Aerial cleared and the single storey garage can be seen clearly, the nursery to the Photography east of the site has been converted to a residential property. Around 2014 the site is shown to have been combined into a single plot with the garage to the rear of ‘The White House’ cleared and the garage to the rear of ‘The Deri’ as it is today. The layout of the site is shown to be as it is presently with a static caravan along the northern boundary. Following consultation with the planning department at EFDC, a number of planning records were supplied for the three properties to the north of Review of the site of which it used to be a part, ‘The Deri’, ‘Meadow View’ and ‘The Planning White House’. These can be made available upon request and with regards Records to ‘The Deri’ the most pertinent of these relates to the construction of a detached garage, permitted in 1984, which is the same structure noted on site today. The microfiche records for ‘Meadow View’ relate to permitted

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Detail Description war damage repairs in 1946 and the emptying of a cesspool in 1962. Records pertaining to ‘The White House’, formerly known as ‘Fleur’ and before this ‘Cromer’, relate to an application for a two storey rear extension granted in 1971 and approval for a single garage given in 1979 with access road running to the rear. This garage is shown to be sited on a concrete pad 17 square feet which is likely the competent concrete slab noted on site during the walkover it should be noted that drawings for this detail the concrete structure as having asbestos roofing.

2.7 Unexploded Ordnance (UXO) Risk

The planning records obtained from Epping Forest District Council refers to repairs made to the properties adjacent to the north of the site due to damage sustained from the war. Given this and the fact that the Charlton Mead Industrial estate sits within the surrounding area a search of publicly available data from bombsight.org and zeticaUXO.co.uk has indicated a moderate risk posed by UXO at the site. It is therefore recommended that a preliminary UXO assessment is performed prior to any groundworks taking place. A detailed UXO assessment may be required depending on the findings of this preliminary assessment.

2.8 Site History

A summary of historical map data from 1873 to 2014 is provided below and copies of relevant historic maps and any others examined during the investigation are included in this report as Appendix H.

• Mapping from the early 1870’s shows Dobbs Weir Road to be in place and the site to stand in an area of undeveloped fields, the nearest development is the Fish and Eels public house 275m away to the north west. • This situation remains unchanged until 1920 where some limited residential development has taken place mainly along Dobbs Weir Road but also along several new roads that run perpendicular to this. The large open field to the north is marked ‘liable to flooding’. • Derby Road has been constructed by 1939 and the site has now divided across several properties, the eastern of which is occupied by a nursery building. There is also a large greenhouse adjacent to the south of the site and both of these features are shown to be clear by 2002. Part of the north western extent of a pit is present just over 250m away and a large nursery is shown the same distance away to the east. Between the late 1930’s and 1960 the boating lake (Nazeing Mead) was created, thought to be from old gravel pits, and further lakes were created in the area in the 1980’s. • In the early 1960’s the Charlton Mead Industrial Estate approximately 300m to the northwest had started to develop whilst there had also been increased residential development in the area. Towards the end of the 1960’s the site is comprised of the garden areas of four residential properties and an electricity substation lies approximately 100m to the northwest. • As part of these gardens mapping from the mid-1980’s shows that there are structures on site as part of the gardens, either sheds or garages. Between this point and the present day the site has been amalgamated into one area and is as it is today. Satellite imagery from 2000 shows the large open area 40m to the north as a large pit, possibly for the extraction of sand and

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gravel and this is shown to be a lake by 2003 before being totally infilled in approximately 2006 and left as an open field.

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3 CONCEPTUAL MODEL AND PRELIMINARY RISK ASSESSMENT

The following section provides a review of the contaminant linkages that may be active at the site through examination of the potential sources that may be present as a result of historic and / or current site activities and where potential interaction between these sources and the identified human / environmental receptors may occur.

3.1 Source Characterisation

The following potential contaminant sources have been identified at the site and in the surrounding area:

Principal Potential Source Description Contaminants of Source Concern In-fill material of unknown origin (Made Ground) used to level areas beneath existing / historic buildings and hardstanding. PAH, Metals, ACM Current & Stockpile of unknown material reported to have Historic Site originated from on site. Use

Pesticides & Potential historic use of the site as a nursery. Herbicides

Several large areas of current and historic landfill Landfill Gas within the surrounding area, the closest of which is (CO , CH ) located 40m to the north. 2 4 Current & Metals, SVOC Historic Land adjacent to the south and east historically used (including PAH), Surrounding as nurseries along with the presence of other TPH, ACM, Land Site Use historic structures. Pesticides & Herbicides Electricity sub station located approximately 100m PCB’s, TPH offsite. Notes: TPH Total Petroleum Hydrocarbons PAH Polycyclic Aromatic Hydrocarbons PCB Poly Chlorinated Biphenyls SVOC Semi-Volatile Organic Compounds ACM Asbestos Containing Material CO2 Carbon Dioxide CH4 Methane

3.2 Potential Receptors

A framework for the assessment of risks arising from the presence of contamination in soils has been produced by the Environment Agency and the Department for the Environment, Food and Rural Affairs (DEFRA) and is presented with the report: ‘Using Science to Create A Better Place: Updated Technical Background to the CLEA Model – Science Report SC050021/SR3’. This guidance document defines a series of standard land-uses, which form a basis for the development of an Environmental Conceptual Model.

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The proposed development plan for the site includes the erection of four residential properties. This proposed future land use, as defined within Science Report SC050021/SR3, has been considered as:

• Residential

In view of the environmental setting, current and potential future land use of the site and surrounding sites, the potential receptors for any contaminant impact are discussed below:

Receptor Site Specific Description Future site users, site workers involved in the site redevelopment, and Human those working and living in the surrounding area have the potential to be at risk from exposure to potential contaminants of concern (CoCs). The site is reported to be underlain by superficial Alluvium deposits and underlying bedrock of the Lambeth Group, both of which is defined by the EA as a Secondary ‘A’ Aquifer, and the historic borehole log does indicate that shallow groundwater is likely to be present. Whilst the site does not Groundwater lie within a SPZ for nearby groundwater abstraction, one is located roughly 12m away and therefore the underlying geology may have some resource potential and groundwater should be considered as a potential receptor to site derived contaminants. A number of surface watercourses are present within the surrounding area including the Nazeing Mead Lake around 87m south of the site. It is possible that site derived contaminants of concern may enter these Surface Water watercourses by overland flow, migration through unsaturated soils or entering shallow surface drainage / historical land drainage which discharges to these drains, therefore surface waters must also be considered as a sensitive receptor within the conceptual site model. The proposed development includes the provision of domestic garden Flora and areas. Some of the identified contaminants of concern are known to be Fauna phytotoxic and as such, the potential for this impact should be considered.

Subsurface structures are likely to be present at the site which may be Buildings & adversely affected by the potential presence of the identified contaminants Infrastructure of concern. These include concrete used in building foundations, buried potable water supply pipes and other service lines and pipes. Adjacent properties including private residential dwellings could also be at Adjacent Land risk from potential contaminants found at the site.

3.3 Potential Pathways

Where contaminants may be present in soil, there are a number of potential pathways that enable human receptors to come into contact with or be exposed to them. The most direct pathways, considered under current UK legislation, can be summarised as follows:

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• Direct ingestion of contaminated soil • Dermal contact with household dust • Ingestion of household dust • Inhalation of fugitive soil dust • Ingestion of contaminated vegetables • Inhalation of fugitive household dust • Ingestion of soil attached to vegetables • Inhalation of vapours outdoors • Dermal contact with contaminated soil • Inhalation of vapours indoors

Clearly, not all of these potential pathways apply for every standard land-use; the simplest example for exclusions being a commercial / industrial site which is covered by concrete hardstanding. The concrete precludes the direct exposure of humans working at the site to any contaminated soils.

However, in addition to direct exposure pathways, a number of physical transport mechanisms / pathways may also exist at a site that allow remote or less accessible contaminants in soil or groundwater to reach human or environmental receptors both at a site and beyond the site boundary. These include the following:

• Downward and lateral movement of • Direct seepage or leaching of contaminants in soil either by gravity or contaminants from soil into subsurface through being ‘leached’ by percolating drains or supply pipework. rainwater. • Lateral migration of contaminants • Volatilisation of contaminants from dissolved in groundwater. groundwater or unsaturated soils into buildings or outdoor air.

Through examination of the standard land use and environmental setting at each site, the presence of pathways and transport mechanisms described above must be considered when assessing whether a contaminant linkage may plausibly be active, and therefore be included in the conceptual site model.

3.4 Summary of Contaminant Linkages

Considering the site use and environmental setting, and the proposed land use; the plausible contaminant linkages that require further investigation are summarised in the following table:

Source Pathway Receptor Direct contact and inadvertent Construction workers during ingestion by eating or smoking with redevelopment & site users dirty hands

Inhalation of fugitive dusts Contaminated soil Ingress / diffusion through permeable potable water supply Site users pipes Migration of ground gas to indoor and outdoor air

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Direct uptake via root systems Plants

The following comments are made with respect to contaminant linkages which have been considered through development of the conceptual model, but have not been concluded as ‘plausible’ – i.e. through which a significant possibility of significant harm could occur to an identified receptor:

• PAHs and metals have been identified as contaminants of concern associated with the historic onsite infill (made ground) and mounds of spoil, however these contaminants are considered to be relatively immobile in the environment by virtue of their very low solubility and volatility. On this basis, and due to the presence of a layer of low permeability cohesive soils encountered above the sands and gravels in the historic borehole log, plausible pathways by which these potential contaminants could pose a significant risk to groundwater or the nearby surface watercourses are not considered to be active. • Whilst the majority of relatively modern electrical transformers do not contain insulation oils containing PCBs, the electricity sub-station identified nearby to the site does represent a potential off-site source that could contain PCBs. However, given the distance of this sub- station and limited mobility of PCBs in the environment, this source is not considered to pose a significant risk to the proposed development. • Although the correspondence obtained from Epping Forest District Council suggests that the site was previously used as a nursery a review of historical mapping and microfiche documents does not show any evidence for this. Whilst it is still recognised that land adjacent to the south and east of the site have hosted horticultural nurseries there are not considered to be risks associated with usage on site.

The following diagram provides an illustration of the plausible contaminant linkages that may be active at the site and which may need further investigation or control to ensure safe development:

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Rear of the Deri, Dobbs Weir – Illustrative Conceptual Site Model

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4 GEOTECHNICAL GROUND MODEL

Geological records indicate the site to lie on superficial alluvium (sands and gravels) above bedrock of the Lambeth Formation with the Lewes Nodular Chalk Formation below. Although given the historic use, some limited/localised made ground is anticipated to be present at the surface. A conceptual geotechnical ground model is provided in the table below which assesses design elements, anticipated strata and ground conditions:

Anticipated Element Parameter(s) Anticipated Conditions Strata Allowable Not appropriate as a bearing strata Bearing Pressure Made Ground Settlement High sensitivity

Volume Change Depends upon the soil composition Allowable 75kN/m2 to 125kN/ m2 Bearing Pressure Foundations Alluvium Settlement Moderate Sensitivity Low to moderate volume change Volume Change potential Allowable 95kN/m2 to 125kN/ m2 Bearing Pressure Lambeth Low sensitivity / Long term Settlement Formation consolidation under loading Moderate to high volume change Volume Change potential Not suitable for infiltration Made Ground drainage May to be suitable for infiltration Drainage Alluvium Permeability drainage Lambeth Unlikely to be suitable Formation Made Ground Low to moderate risk of high Alluvium Concrete Grade Grade sulphate levels Lambeth Formation

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Potential Hazard Comment Trees were not identified at or near the site that could impact Trees & Vegetation foundation design, particularly given that the near surface geology is expected to be predominantly granular. Foundations are anticipated to be present on site associated Below Ground Structures with the existing structures. Granular soils are expected at the site and may not be reliable Excavation Stability for short term excavations. Slopes No slopes were identified during the walkover.

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5 CONCLUSIONS & RECOMMENDATIONS

This Phase I Desk Study has identified that a number of plausible contaminant linkages have the potential to become active as a result of the historic use of the site and presence of large historic landfills in the area.

The contaminant linkages which carry the greatest potential risks at this site comprise the following:

• Human health risks associated with interaction between future residents and potentially contaminated shallow soils, especially within domestic garden areas. • Potential exposure of site workers to contaminated soils during the proposed redevelopment. • Migration of landfill gas to indoor and outdoor air

In accordance with the Model Procedures for Management of Land Contamination (Contaminated Land Report 11) the risks identified by this work will require further assessment in order to determine the most appropriate action for this site.

It is therefore recommended that, initially, the identified plausible contaminant linkages should be further investigated by means of exploratory intrusive investigation. This should consist of undertaking point sampling of the shallow soils in sensitive areas i.e. proposed garden areas, as well as the installation of gas monitoring wells and a detailed gas monitoring programme to assess the risks posed by landfill gas potentially originating from landfills within the surrounding area. It may be prudent to undertake this investigation subsequent to the removal of the large soil mound on site which would currently obstruct appropriate investigation. A detailed scope will be presented for review by Epping Forest District Council prior to commencement which will be in accordance with the guidance outlined in Section 1.2 and the British Standard 10175:2011+A2:2017, the Code of Practise for Investigation of Potentially Contaminated Sites.

Any impacts to soil quality by source contaminants which are identified by the exploratory investigation may require further targeted intrusive investigations in order to delineate the contaminants found and quantitatively evaluate the risks posed.

It is recommended that a preliminary UXO assessment is undertaken at the site prior to any groundworks taking place to quantify the risk posed at the site.

A copy of this report should be provided to the Environmental Health department of Epping Forest District Council so that the information may be used to support planning proposals for the site.

16 Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

FIGURES

Approximate Site Location Crown Copyright. All rights reserved. Licence Number: 100054115

Title: Site Location Plan

Scale: NTS Project: Rear of the Deri, Dobbs Wier Road, Roydon, Drawn By: DB Approved By: MJ Essex, EN11 0BQ Job No: UK18.4199 Fig No: 1 Dwg No: RearofDeri/1018/01 Date: October 2018 Key: Approximate Site Boundary Crown Copyright. All rights reserved. Licence Number: 100054115

Title: Current Site Layout Plan

Scale: NTS Project: Rear of the Deri, Dobbs Wier Road, Roydon, Drawn By: DB Approved By: MJ Essex, EN11 0BQ Job No: UK18.4199 Fig No: 2 Dwg No: RearofDeri/1018/02 Date: October 2018 Key: Approximate Site Boundary Crown Copyright. All rights reserved. Licence Number: 100054115

Title: Aerial Photograph

Scale: NTS Project: Rear of the Deri, Dobbs Wier Road, Roydon, Drawn By: DB Approved By: MJ Essex, EN11 0BQ Job No: UK18.4199 Fig No: 3 Dwg No: RearofDeri/1018/03 Date: October 2018 Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

APPENDICES

Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

APPENDIX A

Site Walkover Notes and Selected Site Photographs

4 5 1 3

2 6

Key: Approximate Site Boundary Crown Copyright. All rights reserved. 1 Approximate Site Boundary Licence Number: 100054115

Title: Photograph Location Plan

Scale: NTS Project: Rear of the Deri, Dobbs Wier Road, Roydon, Drawn By: DB Approved By: MJ Essex, EN11 0BQ Job No: UK18.4199 Fig No: Appendix A Dwg No: RearofDeri/1018/A Date: October 2018 Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

Photo 1: View across the east of the site with the overgrown Photo 2: Image of the west of the site. area to the rear.

Photo 3: View of the south west with the storage container in Photo 4: Image of the levelled area for the static caravan on the area of the former garage. site.

Photo 5: Photograph of the concrete pad from the previous Photo 6: The garage building on site to the rear of the garage. Deri.

Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

APPENDIX B

Indicative Proposed Development Plan

soleconcepts ltd Architectural, Structural Services

Unit 3, Haslemere estate, Charlton Mead Lane, Hoddesdon, Hertfordshire, EN11 0DJ T. 01992 446250 E. [email protected]

Rev Date Description

Disclaimer Note: 1. This drawing is copyright. 2. Contractors must check all dimension on site. 3. Figured dimensions are to be used in preference to scaled dimensions. 4. Discrepancies must be reported immediately. 5. Owner(s) to comply with all requirements to Party Wall Act 1996 prior to commencement of work. 6. Construction (Design & Management) Regulation 2007:

All persons associated with this project in particular (but not exclusively) the instructing Client, The Principal Contractor, Sub-Contractors and other Designers are hereby notified and/or reminded of their obligations under Health & Safety legislation in general and in particular under the Construction (Design & Management) Regulation 2007 and any subsequent amendments that may be issued from time to time).

Sole Concepts Ltd states that, in developing the design of the works, the Health & Safety of the builders and the users of the construction have been considered in accordance with the above regulations and declare that all reasonable efforts have been made to see that the construction and the use of the work/building will be without any risks greater than those associated with the normal construction and use of a building of this type and size

Scale Bar 1:100 Orientation: 0 1 2 3 4 5

0 0.5 1 1.5 2 2.5 Scale Bar 1:50

Project: Project Number: 2890 2x 4 Bedroom Semi Detached house 2 Bedroom Bungalow Issue Type: Planning

Site: Date: Aug 18 Land Rear of the Deri Scale: 1:200 @ A3

Title: Drawn by: MO Proposed Location Plan Checked by:

Drawing No: Revision: 2890-18A3-07 Phase I Geo-Environmental Desk Study Rear of the Deri, Dobbs Weir Road, Roydon EPS Ref: UK18.4199

APPENDIX C

Surrounding Land Use

1. Historical Land Use

NW N NE

W E

SW S SE © Crown copyright and database rights 2018. Ordnance Survey licence 100035207.

Report Reference: GS-5476355 Client Reference: UK18_4199_PO20514 2. Environmental Permits, Incidents and Registers Map

NW N NE

W E

SW S SE © Crown copyright and database rights 2018. Ordnance Survey licence 100035207.

Report Reference: GS-5476355 Client Reference: UK18_4199_PO20514 3. Landfill and Other Waste Sites Map

NW N NE

W E

SW S SE © Crown copyright and database rights 2018. Ordnance Survey licence 100035207.

Report Reference: GS-5476355 Client Reference: UK18_4199_PO20514 4. Current Land Use Map

NW N NE

W E

SW S SE © Crown copyright and database rights 2018. Ordnance Survey licence 100035207.

Report Reference: GS-5476355 Client Reference: UK18_4199_PO20514 8. Designated Environmentally Sensitive Sites Map

NW N NE

W E

SW S SE © Crown copyright and database rights 2018. Ordnance Survey licence 100035207.

Report Reference: GS-5476355 Client Reference: UK18_4199_PO20514