BAE Systems Operations Ltd Woodford Aerodrome
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Woodford Aerodrome BAE Systems Operations Ltd Desk Study for Potential Contamination Woodford Aerodrome BAE Systems Operations Ltd DOCUMENT CONTROL FS38745 EMS 54524 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental EXECUTIVE SUMMARY Introduction and Objectives BAE Systems Environmental was commissioned by BAE Systems Operations Ltd to conduct a Preliminary Risk Assessment for Land Contamination (PRALC) on the BAE Systems Woodford Aerodrome at Chester Road, Woodford, Cheshire; an airfield and an aircraft assembly facility. The objective of the desk study is to carry out a contaminated land assessment of Woodford Aerodrome as part of the corporate Contaminated Land Strategy. The desk study and site reconnaissance will also enable appropriate information about the Site to be collected to assist any potential intrusive investigations. Site Characteristics The Site, which is centered on National Grid Reference SJ 900 825, occupies an area of approximately 205 hectares with an elevation of approximately 90mAOD. The Site is bound to the north by residential and commercial properties. To the east is a railway line, beyond which are residential properties and Adlington industrial estate. To the south is mostly agricultural land with a small group of residential properties. To the west is a small residential development and agricultural land. BAE Systems Woodford is currently involved with the assembly of aircraft (currently Nimrod) and the painting and paint stripping of aircraft. The Site consists of one main runway and four taxiways. The buildings on the Site are concentrated mainly into two areas: the main assembly areas to the north of the Site, and the main painting and stripping area located at the south of the Site. A large number of the buildings across the Site that were formerly used for assembly are now utilised for storage of aircraft components. Six named surface water courses are located on the Site, the majority of which flow to the River Dean located in the southern area of Site, an exception to this is Poynton Brook to the east of the Site as this is a tributary to the Mersey. The use of the Site has changed very little from the development of the Airfield on what was a greenfield site in 1920’s and 1930’s. Environmental Setting Geological records and borehole logs indicate the majority of the Site to be underlain by Glacial Till. Glacial Sand and Gravel and Peat deposits are identified within the centre of the Site. Fluvio- Glacial Gravel deposits are located to the east and south east of the Site. Glacial Sand and Gravel and Alluvium deposits are mapped adjacent to the southern boundary of the Site. A BGS borehole located to the south east of the Site records clays and sands to the base of the borehole, which was terminated at 8.0m below ground level The solid geology beneath the Site comprises of Pebble Beds to the east and the Upper Mottled Sandstone to the west of the Site. Both stratum form part of the Sherwood Sandstone Group, of Permian Triassic age. Four faults are indicated on the geological map across the Site, running in a north – south direction. A borehole located 700m to the west of Site confirms the presence of solid geology at 20.7 mbgl. The report identifies Glacial Till underlying the Site to be a non aquifer due, to its negligible permeability. The presence of groundwater within the Glacial Till is likely to be restricted to any sand and gravel horizons and may not be laterally continuous. The Glacial Sands and Gravels are classified as a Secondary B Aquifer due to their moderate permeability. Groundwater within the solid geology beneath the Site is identified to be a Principal Aquifer. This classification relates A0787-00-R2-1 i OCTOBER 2011 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental to deposits with high intergranular and/or fracture permeability implying they provide a high level of water storage. The Site lies within a Zone II and a Zone III Source Protection Zone. Two source protection boreholes are located within 1000m of the Site, borehole reference NW001 is located 375m to the south of Site and borehole NW148 is located 705m to the northwest of the Site. Initial Conceptual Model and Potential Pollutant Linkages The Conceptual Site Model (CSM) is a simplified representation of the environmental conditions at the Site and its surroundings that enables third parties to build up a picture of the Site. Due to the large number of potential sources of contamination identified on the Site there remains the possibility that on Site sources of contamination may exist. These potential sources are listed below. Made Ground placed during Ash fill area near coal fired Plating activities (e.g the construction of the boiler house as detailed in the degreasing, alchroming etc) factory. Environ Report. The paint store, painting and The Ordnance depot, explosives Waste storage areas (both stripping processes. store and positions of anti- historic and current waste aircraft guns. storage). Historic Fuel tanks (UST’s) The demolition of Site buildings Made Ground where new associated pipework and that were undertaken at the Site. site levels required infilling engines containing aviation of the existing ponds. fuel and diesel. The garage processes. The old fire training pit. AST’s, associated pipework and engines. Landfill area within pit area. Boiler houses. Sewerage treatment areas. Chemical storage Substations. Airfield Known pollution incidents The occurrence of any contamination is most likely to be within localised hotspots around drains and floor slabs of the former process buildings, around fuel storage tanks and areas of previous landfilling. Several pathways have been identified on Site. A pathway is a means by which a receptor can be exposed to, or affected by, a contaminant. The current pathways on Site include migration through the unsaturated zone, via underground services, groundwater, via soil and service trenches, from ingestion of contaminated soil, inhalation of vapour and direct contact with contaminated soil. A total of four receptors have been identified that could be adversely affected by potential on site sources. The first of these is groundwater this includes the shallow groundwater within the Glacial Till, perched water within Made Ground and the deeper groundwater within the major aquifer. The second identified receptor is the six surface waters located on the Site. Also identified as a potential receptor are future site users following any future redevelopment and maintenance personnel. The final receptor identified on Site is any buildings in particular the building fabric and underground services. A0787-00-R2-1 ii OCTOBER 2011 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental Recommendations To address the potential distribution of contaminants, and the pollutant linkages that may be associated with them, it is recommended that an intrusive investigation is undertaken. The investigation should concentrate on establishing firstly whether contamination sources exist at the Site and whether these have caused, are causing or are likely to cause harm or pollution to receptors at the Site. The investigation should comprise the sampling of soils (including appropriate leachability testing of soils) and surface and ground water’s with testing for contaminants of concern and subsequent appropriate risk assessments. In addition surface water sampling off the Site should also be undertaken in order to assess if the Site is impacting on the quality of the local surface waters. The investigation should also be undertaken to determine the nature of the underlying geology at the Site and the depth to the solid strata. An intrusive investigation would also assist in setting an environmental baseline for the Site from which future potential environmental impacts can be measured. A0787-00-R2-1 iii OCTOBER 2011 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental CONTENTS PAGE NO 1. INTRODUCTION 1 2. SITE DETAILS AND DESCRIPTION 2 3. ENVIRONMENTAL SETTING 4 4. EXISTING REPORTS AND SITE INVESTIGATIONS 8 5. HISTORICAL DEVELOPMENT & SITE ACTIVITIES 10 6. WALKOVER SURVEY 14 7. UNEXPLODED ORDNANCE 23 8. ADDITIONAL ENVIRONMENTAL INFORMATION 25 9. INITIAL CONCEPTUAL SITE MODEL 30 10. PRELIMINARY RISK ASSESSMENT 38 11. RECOMMENDATIONS 40 TABLES TABLE 1 PROPERTY DETAILS TABLE 2 GEOLOGY TABLE 3 LICENSED WATER ABSTRACTIONS ONE KILOMETRE RADIUS OF SITE TABLE 4 UXO FREQUENCY TABLE 5 POTENTIAL SOURCES TABLE 6 POTENTIAL PATHWAYS TABLE 7 POTENTIAL RECEPTORS A0787-00-R2-1 iv OCTOBER 2011 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental FIGURES FIGURE 1 SITE LOCATION PLAN FIGURE 2 SITE LAYOUT PLAN FIGURE 3 EXTRACT OF GEOLOGICAL MAP FIGURE 4 EXTRACT OF GROUNDWATER VULNERABILTY MAP APPENDICES APPENDIX 1 SITE WALKOVER PHOTOGRAPHS APPENDIX 2 BGS LOGS – SUPERFICIAL DEPOSITS APPENDIX 3 BGS LOGS – SOLID GEOLOGY APPENDIX 4 ENVIROCHECK REPORT APPENDIX 5 COAL AUTHORITY LETTER APPENDIX 6 HISTORICAL MAPS APPENDIX 7 AERIAL PHOTOGRAPHS APPENDIX 8 ANNOTATED SITE LAYOUT PLAN APPENDIX 9 BUILDING NUMBER PLAN APPENDIX 10 TANK LOCATION PLAN APPENDIX 11 SERVICE PLANS APPENDIX 12 ASBESTOS REGISTER APPENDIX 13 POLLUTION INCIDENT LETTERS APPENDIX 14 LOCAL AUTHORITY SEARCH A0787-00-R2-1 v OCTOBER 2011 Woodford Aerodrome, Cheshire BAE Systems Operations Ltd. BAE Systems Environmental 1. INTRODUCTION 1.1. Background and Objectives BAE Systems Environmental was commissioned by BAE Systems Operations Ltd to conduct a Preliminary Risk Assessment for Land Contamination (PRALC) on the BAE Systems Woodford Aerodrome at Chester Road, Woodford, Cheshire; an airfield and an aircraft assembly facility. The objective of the desk study was to carry out a contaminated land assessment of Woodford as part of the corporate Contaminated Land Strategy. This assessment has been conducted in general accordance with current industry good practice guidance documents and within the UK legislative and policy framework. 1.2. Scope of Work The Site is located and delineated in Figures 1 and 2 respectively.