Marine Aggregate Dredging: Helpingto Determine Good Practice
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Marine aggregate extraction Helping to determine good practice Cover Photograph Credits Top Row: Left - British Marine Aggregate Producers Association Centre - Crown Copyright 2007, Courtesy of Cefas Right - St Andrews University & English Heritage Middle Row: Left - Wessex Archaeology & English Heritage Centre - Marine Ecological Surveys Ltd Right - British Marine Aggregate Producers Association Bottom Row: Left - Crown Copyright 2007, Courtesy of Cefas Centre - British Marine Aggregate Producers Association Right - Wessex Archaeology & English Heritage Designed by Graphics Matter Limited Printed by Healeys Printers Limited Printed on paper containing 75% recycled fibre content MARINE AGGREGATE DREDGING: HELPINGTO DETERMINE GOOD PRACTICE MARINE AGGREGATE LEVY SUSTAINABILITY FUND (ALSF) CONFERENCE PROCEEDINGS: SEPTEMBER 2006 Edited by R.C. Newell D.Sc(Lond.)1, 2 and D.J. Garner M.Sc2 The past and present contributions of the following individuals and organisations to the Marine ALSF Steering Group is gratefully acknowledged: Defra: Andy Greaves (Chair), Paul Leonard, Jamie Rendell, John Maslin The Crown Estate: Mike Cowling, Tony Murray Marine Ecological Surveys: Richard Newell, Dave Garner CEFAS: Kate Francis, Sian Boyd, Dave Carlin, Chris Vivian BMAPA: Mark Russell, Richard Griffiths JNCC: Zoe Crutchfield, Tracy Edwards Natural England: Ian Reach, David Hodson, Victoria Copley, Neil Clark, Keith Duff CLG: Bill MacKenzie, Brian Marker English Heritage: Vir Dellino- Musgrave, Kath Buxton, Ian Oxley, Chris Pater MIRO: Derren Cresswell, Kate Barton HR Wallingford: Alan Brampton This publication, and references within it to any methodology, process, service, manufacturer, or company does not necessarily constitute its endorsement or recommendation by Defra or any of the delivery partners. A limited number of copies of this publication are available from Kate Francis, E-mail [email protected] 1 Marine ALSF Science Co-ordinator 2 Marine Ecological Surveys Limited, 24A Monmouth Place, Bath BA1 2AY FOREWORD Much of Britain’s infrastructure has been built using marine aggregates. They are in homes and hospitals, shops and schools, roads, and even the Channel Tunnel. In some cases they are in the fabric of the very defences that protect our coastal communities from the sea. But their extraction inevitably comes at a price for the marine environment. Some of the impacts of aggregate dredging may, over time, be repaired. Some species may return to a dredged area, but others may not, and geological or archaeological resources can be lost forever in the extraction process. Government has long recognised that it is essential to balance the needs of the environment with the social and economic needs of the nation. It is what that well worn phrase ‘sustainable development’ is all about. We have to ensure that, in taking natural resources, we minimise the impact of our actions on both the surrounding environment and on future generations. In short, we have to live within our means. With this in mind, the Government launched the Aggregates Levy, and the Aggregates Levy Sustainability Fund in 2002. The Aggregates Levy is an environmental tax on industry for the extraction of aggregates. It reduces demand for primary aggregates by increasing their cost, making the use of recycled materials more viable. The Aggregates Levy Sustainability Fund provides money to reduce the environmental impacts of extraction, supporting research to assess and mitigate damage caused by dredging. Since the Fund’s creation, Defra has allocated around £9 million on marine-related research. The range of research has been wide, it has needed to be because historically we have had relatively limited knowledge of the ability of the sea to recover from the aggregate dredging process. We have got little baseline information on what can recover and what could be lost forever. Without this information, it’s very difficult to assess where aggregate extraction is acceptable, where it is not, and where its impact can be minimised. Another gap in our knowledge is knowing what variety of marine resources are actually in the areas where extraction is proposed. After all, neither industry, conservationists, nor regulators can make informed decisions on where dredging can go ahead, unless they have information on what is happening in that area and what the potential impacts may be. The Fund has therefore supported projects like the British Geological Survey (BGS) seabed habitat mapping in the eastern English Channel, and surveys of archaeological finds from the southern North Sea. In the Marine area, in particular, we have placed considerable emphasis on sharing the information the Funds projects have collected, with the wider world. This book is in that tradition and forms both a valuable record of the work undertaken and a reference source for those working in this area. Ben Bradshaw MP, Minister of State for Local Environment, Marine and Animal Welfare CONTENTS FOREWORD 2 Ben Bradshaw MP CONTENTS 3 PREFACE 7 Roger Bright, Chief Executive, The Crown Estate THE MARINE ALSF - OBJECTIVES AND ACHIEVEMENTS R.C. Newell, Marine ALSF Science Co-ordinator 8 SECTION I NATURAL SEABED RESOURCES 14 Identification of seabed resources 16 T. Tew A summary of the Defra R&D funded research project ‘The role of seabed mapping techniques in 18 environmental monitoring and management’ R.A. Coggan & S.E. Boyd Eastern English Channel marine habitat map 24 J.W.C. James, R.A. Coggan, V.J. Blyth-Skyrme, A. Morando, S.N.R. Birchenough, E. Bee, D.L. Limpenny, E. Verling, K. Vanstaen, B. Pearce, C.M. Johnston, K.F. Rocks, S.L. Philpott and H.L. Rees Outer Bristol Channel marine habitat study 40 J.W.C. James, A.S.Y. Mackie, E.I.S. Rees, T. Darbyshire, S.L. Philpott, K. Mortimer, G.O. Jenkins & A. Morando Building GIS and environmental data management capabilities of the sea fisheries committees 50 P.D. Eastwood The seabed and inshore fishing activity: Assessment & relationships 54 R.W. Clark, T.M. Dapling, R.L. Foster-Smith, D.R. Hume, R. Irving & K. Rhynas Sand banks and offshore river channels: Examples of geodiversity from aggregate industry sites 58 C.D.R. Evans Marine aggregates and biodiversity in both a 2 and 3 dimensional context 62 N. Thomas & J.W.C. James Recoverability of Sabellaria spinulosa following aggregate extraction 68 B. Pearce, J.A. Taylor & L.J. Seiderer Best methods for identifying and evaluating biogenic and cobbley reefs 76 D. Limpenny, R.L. Foster-Smith, W. Meadows, J. Eggleton & Z. Crutchfield 3 SECTION II RESOURCES OF ARCHAEOLOGICAL & HISTORIC SIGNIFICANCE 80 The importance of archaeological & historic resources 82 I. Oxley & V. Dellino-Musgrave The seabed prehistory project 86 S. Leather, J. Russell, L. Tizzard, D. Paddenburgh & N. Callan Archaeology of continental shelves: A submerged pre-history 90 J. Dix & K. Westley Submerged Palaeo-Arun & Solent Rivers: Reconstruction of prehistoric landscapes 94 S. Gupta, J. Collier, A. Palmer-Felgate, J. Dickinson, K. Bushe & S. Humber Mapping marine historic environment character: England’s historic seascapes programme 98 D. Hooley England’s historic seascapes: Liverpool bay pilot project 102 D. Groom England’s historic seascapes: Solent and Wight and adjacent marine zone pilot area 106 N. Pee & J. Satchell England’s historic seascapes: Scarborough to Hartlepool pilot 108 B. Tapper England’s historic seascapes: Southwold to Clacton and adjacent marine zone pilot area 110 K. Powell England’s historic seascapes: Withernsea to Skegness pilot 112 J. Lyon The North Sea palaeolandscapes project 114 V. Gaffney & K. Thomson Rapid archaeological site surveying and evaluation 120 R. Bates, M. Lawrence, M. Dean, P. Robertson & L. Atallah Wrecks on the seabed: Assessment, evaluation & recording 124 J. Gribble Enhancing our understanding of the marine historic environment: Mapping navigational hazards 128 as areas of maritime archaeological potential O. Merritt, D. Parham & D. McElvogue Identification of historically important shipwrecks 132 D. Parham & P. Palma 4 SECTION III MITIGATION & MANAGEMENT 136 Mitigation and management of marine aggregate dredging 138 M. Russell & I. Selby Marine aggregate extraction – Risk assessment (MARA) framework 142 V. Bain, P. Sayers, C. Adnitt, M. Walkden, S. John & J. Hall An environmental context to the effects of marine aggregate dredging 146 H. Hinz, M. Frost & S. Jenkins Dredge lane management – computational fluid dynamic simulations 150 J. Rees Use of shell to speed recovery of dredged aggregate seabed 152 K. Collins & J. Mallinson Gravel seeding – a suitable technique for restoration of the seabed following aggregate dredging? 156 K.M. Cooper, S. Ware, K. Vanstaen & S.E. Boyd A predictive framework for the assessment of recoverability of marine benthic communities 158 following cessation of aggregate dredging R.C. Newell, J.E. Robinson, B. Pearce, L.J. Seiderer, R.M. Warwick, P.M. Somerfield, K.R. Clarke, H. Jenkins, N. Beer, F. Burlinson & K. Stacey Coupling physical and ecological models: A new approach to predicting the impacts of aggregate 164 extraction on biological recoverability N.J. Frost, J.M. Harris, J.E. Saunders, S.R. Bishop, S.A. Schinaia, R.R. Simons & R.C. Newell Direct measurement of seabed stability at a marine aggregate extraction site using benthic 168 flume technology K. Black, S. Athey & P. Wilson Modelling exclusion zones for marine aggregate dredging 172 J. Dix, D.O. Lambkin, M. Thomas & P. Cazenave A protocol for reporting of archaeological finds at marine aggregate extraction