The Permo-Triassic Sandstone Aquifer of Shropshire
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Baseline Report Series: 20. The Permo-Triassic Sandstone Aquifer of Shropshire Groundwater Systems and Water Quality Commissioned Report CR/05/061N Environment Agency Science Group Technical Report NC/99/74/20 The Natural Quality of Groundwater in England and Wales A joint programme of research by the British Geological Survey and the Environment Agency BRITISH GEOLOGICAL SURVEY Commissioned Report CR/05/061N ENVIRONMENT AGENCY Science Group: Air, Land & Water Technical Report NC/99/74/20 This report is the result of a study jointly funded by the British Geological Baseline Report Series: Survey’s National Groundwater Survey and the Environment Agency’s Science 20. The Permo-Triassic Sandstone Group. No part of this work may be reproduced or transmitted in any form or Aquifer of Shropshire by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright proprietors. All rights are reserved by the copyright P L Smedley, I Neumann and S Brown* proprietors. Disclaimer Contributors The officers, servants or agents of both R Hargreaves (GIS), C J Milne (databasing) the British Geological Survey and the Environment Agency accept no liability whatsoever for loss or damage arising from the interpretation or use of the information, or reliance on the views contained herein. *Environment Agency Environment Agency Dissemination status Internal: Release to Regions External: Public Domain Project No. NC/99/74/20 ©Environment Agency, 2005 Statement of use This document forms one of a series of reports describing the baseline chemistry of selected reference aquifers in England and Wales. Cover illustration Outcrop of the Kidderminster Sandstone at Grindleforge [SJ 753 034] Environment Agency Project Manager: (©NERC 2005). Dr Rob Ward / Jonathan Smith / Dr Sean Burke Key words Science Group: Air, Land & Water Baseline, Permo-Triassic Sandstone, groundwater quality, hydrogeochemistry, British Geological Survey Project Manager: UK aquifer. Bibliographic Reference Dr Paul Shand Smedley, P.L., Neumann I. and Brown, Groundwater Systems & Water Quality Programme S. 2005 Baseline Report Series 20: The Permo-Triassic Sandstone Aquifer of Shropshire. British Geological Survey Commissioned Environment Agency Science Group, Solihull 2005 Report No. CR/05/061N British Geological Survey, Keyworth, Nottingham 2005 ©Environment Agency 2005 ©NERC 2005 BRITISH GEOLOGICAL SURVEY ENVIRONMENT AGENCY The full range of Survey publications is available from BGS The Environment Agency is a non-departmental public body with Sales Desk at the Survey headquarters, Keyworth, Nottingham. particular responsibilities for aspects of environmental regulation The more popular maps and books may be purchased from and management in England and Wales. In discharging these BGS-approved stockists and agents and over the counter at the responsibilities the Agency carries out projects both alone and in Bookshop, Gallert 37, Natural History Museum, (Earth collaboration with others. Galleries), Cromwell Road, London. 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EXECUTIVE SUMMARY 1 2. PERSPECTIVE 3 2.1 Study area 3 2.2 Current issues in groundwater quality 5 3. BACKGROUND TO UNDERSTANDING BASELINE QUALITY 8 3.1 Introduction 8 3.2 Geology 8 3.3 Hydrogeology 14 3.4 Mineralogy and mineral chemistry 19 3.5 Rainfall chemistry 21 3.6 Land use 22 4. DATA AND INTERPRETATION 23 4.1 Data sources 23 4.2 Data quality and handling 23 5. HYDROCHEMICAL CHARACTERISTICS 25 5.1 Introduction 25 5.2 Major constituents 27 5.3 Trace elements 29 5.4 Organic compounds 30 6. GEOCHEMICAL CONTROLS AND REGIONAL CHARACTERISTICS 32 6.1 Introduction 32 6.2 Geochemical controls 32 6.3 Regional trends 44 6.4 Groundwater dating 45 6.5 Temporal variations 46 6.6 Depth variations 48 7. BASELINE CHEMISTRY OF THE AQUIFER 50 8. SUMMARY AND CONCLUSIONS 51 9. REFERENCES 52 ACKNOWLEDGEMENTS 55 i List of Figures Figure 2.1. Map of the study area in Shropshire showing the location of the Permo-Triassic Sandstone aquifer outcrop.............................................................................................3 Figure 2.2. Rolling hills of the Shropshire Permo-Triassic Sandstone looking east towards the Coalbrookdale power station [SJ 655 038] (photograph: I. Neumann).........................4 Figure 2.3. The River Severn at Shrewsbury [SJ 496 122] (photograph: S. Brown). ....................4 Figure 2.4. View of a large meander in the River Severn near Leighton with rolling hills formed by the Permo-Triassic Sandstone [SJ 620 045] (photograph: I. Neumann)..................5 Figure 3.1 Geological map of Shropshire showing the area of outcrop of the Permo-Triassic Sandstone. .....................................................................................................................9 Figure 3.2 Geological cross-section of the Permo-Triassic Sandstone extending along the course of the River Tern (see Figure 2.1) (from Bridge et al., 2002). ....................................10 Figure 3.3. View of quarry face in the Permo-Triassic Sandstone near Grindleforge [SJ 753 035] (photograph: I. Neumann)...........................................................................................10 Figure 3.4. Outcrop of the Sherwood Sandstone showing the typical red-bed lithology with cross- bedding and local yellow mottling [SJ 753 035] (photograph: I. Neumann)..............11 Figure 3.5. Map of the distribution of Drift deposits in the study area. ........................................12 Figure 3.6. Outcrop showing detail of dune-bedded Bridgnorth Sandstone cross-bedded with fluvial Kidderminster Conglomerate [SO 733 959] (photograph: S. Brown).............13 Figure 3.7. Detail of cross-bedding in the Sherwood Sandstone showing variation in iron-oxide concentration and possibly redox condition (red/yellow coloration) from a stone wall, Beckbury Church [SJ 764 016] (photograph: I. Neumann). .......................................13 Figure 3.8. Simplified map of land use in the study area showing location of landfill sites. Land- use data are from Land Cover Map 1990, supplied courtesy of the Centre for Ecology & Hydrology, ©NERC................................................................................................22 Figure 5.1. Piper diagram for groundwater samples from the Shropshire