Ecohydrological Conditions at Braunton Burrows: activities to date including work supported by BGS Opportunity Funds FY 2011/2012 Groundwater Science Programme Open Report OR/12/041 If you have a cover picture delete this text and insert it here. Scale the picture to fit the cell BRITISH GEOLOGICAL SURVEY GROUNDWATER SCIENCE PROGRAMME OPEN REPORT OR/12/041 Ecohydrological Conditions at Braunton Burrows: activities to date including work supported by The National Grid and other BGS Opportunity Funds FY Ordnance Survey data © Crown Copyright and database rights 2012. Ordnance Survey Licence 2011/2012 No. 100021290. Keywords Opportunity Funds, coastal 1 1 2 3 dunes, Brauton Burrows. D Allen , W G Darling , M L M Jones , Mountford O , Robins N S1, Stratford C J3 and Wallace H4 Front cover Pulling out the continuous sleeved core after drilling down one metre core length. Bibliographical reference ALLEN D, DARLING W G, JONES M L M, MOUNTFORD O, ROBINS N S, STRAFORD C J AND WALLACE H . 2012. Ecohydrological Conditions at 1British Geological Survey, Crowmarsh Gifford, Wallingford, OX10 8BB, UK. Braunton Burrows: activities to date including work supported by 2Centre for Ecology and Hydrology, Bangor, Gwynedd, LL57 2UW, UK. BGS Opportunity Funds FY 2011/2012. British Geological 3Centre for Ecology and Hydrology, Crowmarsh Gifford, Wallingford, OX10 Survey Open Report, OR/12/041. 8BB, UK. 29pp. 4 Copyright in materials derived Ecological Surveys (Bangor), Canon Pyon, Hereford, HR4 8PF, UK. from the British Geological Survey’s work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, e-mail [email protected]. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract. Maps and diagrams in this book use topography based on Ordnance Survey mapping. © NERC 2012. All rights reserved Keyworth, Nottingham British Geological Survey 2012 BRITISH GEOLOGICAL SURVEY The full range of our publications is available from BGS shops at British Geological Survey offices Nottingham, Edinburgh, London and Cardiff (Welsh publications only) see contact details below or shop online at www.geologyshop.com BGS Central Enquiries Desk Tel 0115 936 3143 Fax 0115 936 3276 The London Information Office also maintains a reference collection of BGS publications, including maps, for consultation. email [email protected] We publish an annual catalogue of our maps and other publications; this catalogue is available online or from any of the Environmental Science Centre, Keyworth, Nottingham BGS shops. 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Natural History Museum, Cromwell Road, London SW7 5BD Tel 020 7589 4090 Fax 020 7584 8270 Tel 020 7942 5344/45 email [email protected] Columbus House, Greenmeadow Springs, Tongwynlais, Cardiff CF15 7NE Tel 029 2052 1962 Fax 029 2052 1963 Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB Tel 01491 838800 Fax 01491 692345 Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Belfast BT9 5BF Tel 028 9038 8462 Fax 028 9038 8461 www.bgs.ac.uk/gsni/ Parent Body Natural Environment Research Council, Polaris House, North Star Avenue, Swindon SN2 1EU Tel 01793 411500 Fax 01793 411501 www.nerc.ac.uk Website www.bgs.ac.uk Shop online at www.geologyshop.com OR/12/041 Contents Contents ........................................................................................................................................... i Summary ....................................................................................................................................... iii 1 Introduction and background information ......................................................................... 1 1.1 Hydrological Monitoring ................................................................................................ 2 1.2 Topographic Surveys ...................................................................................................... 6 1.3 Vegetation Surveys ......................................................................................................... 8 1.4 Opportunity Fund Project ............................................................................................... 8 2 Deep core drilling of dry dune hills ...................................................................................... 9 3 Hydrochemical and isotopic analysis of vadose moisture and groundwater .................. 10 3.1 Introduction .................................................................................................................. 10 3.2 Groundwater chemistry below Dune slacks ................................................................. 10 3.3 Residence time below dune slacks ............................................................................... 12 3.4 Deep drilling at Braunton Burrows .............................................................................. 14 4 Future activities .................................................................................................................... 19 5 References ............................................................................................................................. 19 Appendix 1 Review of existing unpublished hydrological and vegetation data for all dune sites in order to refine list of sites for full dune wetland vegetation surveys in 2013. 20 Braunton Burrows .................................................................................................................. 20 Lindisfarne ............................................................................................................................. 20 Saltfleetby .............................................................................................................................. 20 Sandscale ................................................................................................................................ 20 Sefton Coast ........................................................................................................................... 21 Winterton ................................................................................................................................ 21 Seascale .................................................................................................................................. 22 Sandscale ................................................................................................................................ 22 FIGURES Figure 1 Idealised conceptual cross section across a coastal dune field. .................................... 1 Figure 2 Typical hydrographs from each of the three transects with 24 month moving average for Bideford rainfall and declining linear trends for each hydrograph. ........................ 2 Figure 3 The older southern transects and the new Transect No. 1. ........................................... 3 Figure 4 1991 to 2010 water level data for dipwells on Transect No. 1. .................................... 4 Figure 5 Continuous water level data, Environment Agency rainfall data, Natural England manual water level data and ground surface level for dipwell CEH 2, in Cotton Slack. ............................................................................................................................ 5 i OR/12/041 Figure 6 Continuous water level data, Environment Agency rainfall data, Natural England manual water level data and ground surface level for dipwell CEH 4. ........................ 5 Figure 7 Continuous water level data, Environment Agency rainfall data, Natural England manual water level data and ground surface level for dipwell CEH 6, Beach Head Slack. ............................................................................................................................ 6 Figure 8 Surface map of Cotton Slack. Green dots indicate locations of vegetation survey quadrats. ....................................................................................................................... 7 Figure 9 Surface map of Beach Head Slack. Green dots indicate locations of vegetation survey quadrats. ....................................................................................................................... 7 Figure 10 Piper diagram of dune slack groundwater chemistry. The diagram is annotated to show where seawater and fresh water would plot. ..................................................... 12 Figure 11 Profiles of δ2H in sand moisture obtained by direct reaction of sand samples from BHs D2 and D4, autumn 2011. Blue datapoints represent analyses of water extracted by centrifuge, showing generally good agreement. Also shown is the rainfall isotope record from Wallingford