Chapter 9: Road drainage and the water environment

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Memorandum (Continued) Page 2 of 6 Lower Lias Clay The solid geology comprises Lower Lias Clay of varying strength from stiff to hard. This material is likely to comprise of closely fissured bluish grey clay with fossil fragments. Within this strata, bands of mudstone and limestone bands are common. 4. Groundwater Data River Terrace Deposits and Alluvium The River Terrace Deposits and Alluvium are classified as minor aquifers usually only of local importance for supporting abstractions or providing baseflow to surface waters. Lower Lias Clay and Glacial Till The Lower Lias strata and Glacial Till deposits are generally classified as non aquifers, however, there is potential for groundwater flow through fissures and rock inclusions within the solid deposits. Also, specific units within the Lower Lias Clay can have minor aquifer status as some of the thin limestones within the strata can yield significant quantities of water. The proportion of water bearing limestones increases towards the base of the Lower Lias Group, forming the Blue Lias or Scunthorpe Mudstone Formation, which is classified as a minor aquifer. On the basis of interpretation of the published geological map, the strata below the proposed scheme are towards the top of the Lower Lias Group sequence, and therefore would indicate non-aquifer status. Correspondence from the EA (2003) indicates that the underlying geology is a minor aquifer, but it is not specific with respect to the various geological formations being referred to. An earlier EA /National River Authority publication classifies the Lias Group as a non-aquifer which is also in accordance with the Envirocheck report and published groundwater vulnerability mapping. The geological memoir notes a cutting for the M1 located approximately 30 m south of the proposed A14- M6 Link at NGR [56137858], where 1.5 m of Glacial Till is underlain by 3m of Lower Lias Clay overlying 6 m of Mudstone. At the foot of the cutting a 15 m limestone band was encountered, described as yielding large quantities of water. Groundwater Abstractions Abstractions below 20 m 3 /day (with a number of exceptions) do not require a licence from the EA; these private supplies are registered with the relevant Local Authority. There is one private well (NGR SP 5610 7775), located at Station House, Lilbourne, approximately 1 km south of the A14-M6 Link. No other information is available. On the basis of location, it would appear to be sourced by groundwater within the river terrace gravels /alluvial deposits. There is one licensed abstraction for 2 wells (NGR SP 5621 798) located approximately 1 km northeast of the A14-M6 Link at Swinford Lodge. The license is for general farming and domestic use all year round but for a relatively small annual volume of 1637 m 3 (and maximum daily rate of 5.5 m 3 ). Groundwater Monitoring Exploratory holes relevant to the Swinford Road Cutting and A14-M6 Link are listed in Table 4.1, including groundwater strikes and other pertinent information. Monthly groundwater monitoring data collected between April 2004 and August 2006 is summarised in Figures 4.1 and 4.2 with average groundwater levels recorded in Table 4.1. Jacobs Engineering U.K. Limited Jacobs_MemoA4.doc
Memorandum (Continued) Page 3 of 6 Table 4.1 Groundwater Data Underpass Swinford Road Cutting Exploratory Hole Groundwater Strike Comments Response Zone ( mAOD) BH216 (04) - - 91.8-89.8 Lower Lias BH3009 (87) - - - - BH1389 (65) 110 Strike within Glacial Till - - BH1390 (65) 111.3 Strike within Made Ground - - BH212 (04) 111.3 BH323 (05) 108.5 Strike within Made Ground, BH dry from 109 mAOD Strike within River Terrace Deposits, BH dry from 106.3 mAOD 100.6-98.6 Lower Lias 106.5-107.8 River Terrace Deposits Average Groundwater Level (mAOD) 113.3 111.9 110.8 A14-M6 Link BH217 (04) - - - - BH210 (04) - - 104.6-102.6 Lower Lias BH22 (04) 97.35 BH102A (04) - BH24 (04) 103.79 BH25 (04) - - BH201 (04) 109.65 BH103(04) 110.71 BH322s (05) BH322d (05) BH203 (04) 111.55 BH321s (05) BH32d (05) - - Strike within Lower Lias Mudstone band at base of borehole Damp within Made Ground at 114.25 and Lower Lias Clay 85.25 mAOD Groundwater not apparent during boring but entered borehole over night Strike within Lower Lias Clay, groundwater present for remainder of boring Strike within Lower Lias Clay, BH dry from 109.7 mAOD Strike within Lower Lias Clay, groundwater present for remainder of boring Strike within Lower Lias Clay, BH dry from 107 mAOD BH dry with slight seepage within Lower Lias Clay at 106.9, 101.7 & 92.7 mAOD 94.35-93.35 Lower Lias 101.25-100.25 Lower Lias 87.89-86.59 Lower Lias 87.43-85.93 Lower Lias 92.65-90.65 Lower Lias 110.71-109.71 Lower Lias 118.72-115.72 Lower Lias 114.72-100.22 Lower Lias 114.55-107.25 Lower Lias 108.79-106.68 Lower Lias 105.68-89.68 Lower Lias 109.4 105.5 110.2 109.5 108.7 108.1 110.8 Dry 110.3 110.8 108.3 107.6 Jacobs Engineering U.K. Limited Jacobs_MemoA4.doc
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M1 Junction 19 Improvement Environm
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M1 JUNCTION 19 IMPROVEMENT ENVIRONM
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Appendix A - Pollution and Spillage
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Method D - Assessment of Pollution
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Groundwater: Hydrocarbons Hydrogeol
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Page 83 and 84: Non Technical Summary Skanska Const
Page 85 and 86: Contents 1 Introduction 1 1.1 Overv
Page 87 and 88: 1 Introduction 1.1 Overview Jacobs
Page 89 and 90: 2 Policy Review 2.1 Planning Contex
Page 91 and 92: When the both the ‘Flood Zone’
Page 93 and 94: 3 Flood Risk to the Proposed Develo
Page 95 and 96: 3.2 Fluvial Flooding - Ordinary Wat
Page 97 and 98: Major earthworks affecting surface
Page 99 and 100: 3.7 Flooding from Infrastructure Fa
Page 101 and 102: 3.9 Summary of Risks to Site Table
Page 103 and 104: 4 Impacts of the Proposed Developme
Page 105 and 106: 4.6 Summary of Flood Impacts from D
Page 107 and 108: 5 Proposed Mitigation Measures 5.1
Page 109 and 110: The extents of this problem are cur
Page 111 and 112: 5.7 Summary of Recommended Mitigati
Page 113 and 114: 6 Residual Risks The level of flood
Page 115 and 116: 7 PPS25 Sequential and Exception Te
Page 117 and 118: 8 Conclusion The M1 Junction 19 Imp
Page 119 and 120: Appendix A Existing Layout, Environ
Page 127 and 128: Appendix B Contractor’s Proposals
Page 129 and 130: Appendix C Hydrogeological Assessme
Page 131: Memorandum Fairbairn House, Ashton
Page 135 and 136: Memorandum (Continued) Page 5 of 6
Page 141 and 142: Appendix D Volume Distribution for
Page 143 and 144: Floodplain compensation area - elev
Page 145: Depth Bands (m) TOTAL (m³) Area Re
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Chapter 9: Road drainage and the water environment

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