OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 Town and Country Planning (Environmental Impact Assessment) Regulations 2017 Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions Document Reference 163390-JAC-REP-EEN-070001 Author Jacobs Date June 2021 Revision Number A01 OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 Environmental Impact Assessment – Appendix 7.1 Geology and Soils Baseline Conditions Document Version Control Version Date Authors Reviewer Approver A01 Jun 2021 J. Thompson & M. Williams A. Naik F. Giacomello Report for: Authored by: Network Rail Jacobs SN1 1180 Eskdale Rd Station Road Winnersh Swindon Reading SN11DG RG41 5TU © Copyright 2021 . The concepts and information contained in this document are the property of Network Rail. Use or copying of this document in whole or in part without the written permission of constitutes an infringement of copyright. Limitation: This document has been prepared on behalf of Network Rail, and for the exclusive use of Network Rail, and is subject to, and issued in accordance with, the provisions of the contract between Jacobs and the Network Rail. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or reliance upon, this document by any third party. OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 Contents 1. INTRODUCTION ................................................................................................. 1 2. SOURCES OF INFORMATION ........................................................................... 2 2.1 Geological .................................................................................................... 2 2.2 Groundsure .................................................................................................. 2 2.3 Other ............................................................................................................ 2 3. SITE SETTING .................................................................................................... 3 3.2 Made Ground ............................................................................................... 3 3.3 Superficial Deposits ...................................................................................... 3 3.4 Bedrock Geology .......................................................................................... 3 3.5 Historical Borehole Logs .............................................................................. 3 3.6 Landfills and Waste ...................................................................................... 6 3.7 Environment Agency and Oxford City Council Consultation ......................... 6 3.8 Pollution Incidents ........................................................................................ 9 3.9 Radon ........................................................................................................... 9 4. SITE HISTORY .................................................................................................. 10 5. SITE RECONNAISSANCE ................................................................................ 17 5.1 Soils and Geology Site Walkover Notes ..................................................... 17 REFERENCES ......................................................................................................... 20 i OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 Tables Table A3.1: Summary of borehole data. .................................................................................. 4 Table A3.2: Consultation responses ....................................................................................... 7 Table A3.3: Pollution incidents ................................................................................................ 9 Table A4.1: Site history ......................................................................................................... 11 Table A5.1: Site walkover findings ........................................................................................ 18 ii OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 1. INTRODUCTION 1.1.1 As part of the Environmental Statement this document presents further detail regarding soils and geology baseline conditions for the Scheme and provides information on historical land use, geology, hydrogeology, site reconnaissance information and consultation responses. These are summarised in the geology and soils main chapter (Volume 2 – Chapter 7). 1.1.2 The site layout is shown in Figure 7.1 in Volume 3 of the Environmental Statement. For definitions, please see Appendix 1.5 – Glossary and Acronyms. For the purposes of this report the Scheme has been divided into four sections: • Botley Road Bridge realignment and replacement; • Western entrance to Oxford Station; • Platform 5 and subway; and • Sheepwash Bridge replacement. Page 1 of 20 OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 2. SOURCES OF INFORMATION 2.1 Geological 2.1.1 The following published geological information available for the area has been reviewed: • British Geological Society (BGS), Geo Index Onshore; • BGS Lexicon of Named Rock Units; • BGS 1:50,000 geological Sheet No.237 Thame, solid and Drift, dated 1994; and • Phase 1 and 2 ground investigation report (Tata Halcrow Joint Venture (THJV), 2014). 2.2 Groundsure • Groundsure Map Insights Report and associated historical maps were reviewed. (Dated January 2020. Reference 6552685). 2.3 Other 2.3.1 The following additional documents and data sources have also been reviewed as part of this desk study: • Multi-Agency Geographic Information for the Countryside (MAGIC); • Contaminated Land Risk Assessment (THJV, 2014); and • Historical reports. Page 2 of 20 OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 3. SITE SETTING 3.1.1 The study area for this assessment is Oxford Station. The extent of the study area is defined by the red line boundary, with an approximate 500m buffer extending from the boundary. This is shown on Figure 7.1 in Volume 3 of the Environmental Statement. 3.2 Made Ground 3.2.1 Made ground is recorded on site along the sidings and offsite to the east, north east and south east. Made ground areas are also present at historical landfill locations. The BGS borehole log SP60NW80 shows made ground to a maximum depth of 0.61m below ground level (bgl). Historical ground investigations show made ground present across the site at various depths. These are described per area of the site in Table A3.1. 3.3 Superficial Deposits 3.3.1 The site is underlain by alluvium. The BGS Lexicon describes alluvium as “unconsolidated detrital material deposited by a river, stream or other body of running water. Alluvium is a general term for clay, silt, sand and gravel.” 3.4 Bedrock Geology 3.4.1 The Oxford Clay Formation and West Walton Formation is known to underlie the site. This is known as a Mudstone. Through review of available nearby borehole data, the full thickness is unknown but is greater than 20m. The material is described as stiff bluish-grey calcareous, shaly clay. The Lambeth Group underlies the Oxford Clay with the Upper Chalk present at depth. The Oxford Clay is known to be absent at scour hollows in the region. 3.5 Historical Borehole Logs 3.5.1 One borehole log 20m east of the station building is available on the BGS Onshore Geoindex. Boreholes were drilled across the site for historical ground investigations. The boreholes are summarised in Table A3.1; locations are shown on Figure 7.2 in Volume 3 of the Environmental Statement. Page 3 of 20 OFFICIAL Network Rail Oxford Corridor Phase 2 Capacity Improvement Scheme Environmental Impact Assessment – Appendix 7.1: Geology and Soils Baseline Conditions 163390-JAC-REP-EEN-070001 Revision A01 Table A3.1: Summary of borehole data. Site Area Geology Description Depth (m.bgl) Comment Boreholes Botley Road Made Variable across site. Locally variant Thickness of made ground related to the height of BH01, WS01, realignment and Ground including ash, brick, Maximum depth the railway embankment. BH06, WS14 bridge replacement; wood, hydrocarbons. 4.2 Superficial Alluvium Locally absent Thickness of Alluvium is variable influenced by the Deposits Where present thickness of made ground as a result of material excavation and placement of made ground 3 – 4.10 River Terrace 4.0 – 9.60 Thickness has great variety across site from 0.97m Deposits – 5.5m due to evolution of river valley Bedrock