Cornwall Beach & Dune Management Plans – Harvey's Towans
Total Page:16
File Type:pdf, Size:1020Kb
REPORT ( FINAL) Cornwall Beach & Dune Management Plans – Harvey’s Towans Prepared for Cornwall Council October 2016 CH2M Ash House Falcon Road Sowton, Exeter EX2 7LB Contents Section Page Executive Summary ...................................................................................................................... v Introduction ................................................................................................................................ 1 1.1 Project Background ....................................................................................................... 1 1.2 Project Aims .................................................................................................................. 3 1.3 Dune Management Plan ............................................................................................... 3 1.4 Key Contacts ................................................................................................................. 3 Site Description ........................................................................................................................... 5 2.1 Location......................................................................................................................... 5 2.2 Setting ........................................................................................................................... 7 2.3 Key Characteristics ........................................................................................................ 7 2.3.1 Present Site ...................................................................................................... 7 2.4 Natural and Historic Environment ................................................................................ 7 2.4.1 Ecology ........................................................................................................... 10 2.4.2 Designated Geological Conservation Sites .................................................... 13 2.4.3 Landscape Setting .......................................................................................... 13 2.4.4 Archaeology and Cultural Heritage ................................................................ 13 2.5 Land Use ...................................................................................................................... 13 2.6 Value of the Dunes ...................................................................................................... 14 2.7 Key Problems Experienced.......................................................................................... 14 2.8 Other Studies .............................................................................................................. 14 2.8.1 Shoreline Management Plan (SMP) Policy .................................................... 14 Factors Affecting the Beach Dune System .................................................................................. 16 3.1 Wind, Wave Climate and Tides ................................................................................... 16 3.1.1 Wave Climate ................................................................................................. 16 3.1.2 Storm Waves .................................................................................................. 17 3.1.3 Tides ............................................................................................................... 18 3.1.4 Climate Change and Sea Level Rise ................................................................ 19 3.2 Sediment Budget and Linkages ................................................................................... 20 3.3 Historical Changes ....................................................................................................... 21 3.3.1 General Description ....................................................................................... 21 3.3.2 Long Term Evolution ...................................................................................... 22 3.4 Summary of Site Influences ........................................................................................ 29 3.5 Future Changes ........................................................................................................... 29 Beach & Dune Management Plan .............................................................................................. 31 4.1 Key Issues .................................................................................................................... 31 4.2 Management Techniques to Apply at Harvey’s Towans ............................................ 31 4.2.1 Dune Stabilisation .......................................................................................... 31 4.2.2 Morphological Modification .......................................................................... 34 4.2.3 Sediment Modification .................................................................................. 35 4.2.4 Ecological Modification .................................................................................. 36 4.2.5 Adapt Backshore ............................................................................................ 36 4.2.6 Access Management ...................................................................................... 37 4.2.7 Manual Maintenance ..................................................................................... 39 4.2.8 Public Awareness ........................................................................................... 39 4.2.9 Monitoring ..................................................................................................... 42 4.2.10 Funding .......................................................................................................... 42 4.3 Plan of Action .............................................................................................................. 44 III CONTENTS Section Page 4.4 Monitoring and Response ........................................................................................... 50 4.4.1 Survey Requirements ..................................................................................... 50 4.4.2 Trigger Conditions .......................................................................................... 52 References ................................................................................................................................ 56 Appendices Appendix A Sand Dune Management Techniques & Preliminary Decision Support Tool v2.0 Appendix B An Overview of Coastal Sand Dunes Appendix C Baseline Report Appendix D Options Appraisal Appendix E Site Actions Summary Map Appendix F Summary Leaflet Document history This document has been issued and amended as follows: Version Date Description Created by Verified by Approved by 0.1 08-03-16 Initial Draft for CC, EA and NE AF, SB, EH JR JR comment 0.2 14-06-16 Draft for stakeholder comment AF, SB, EH JR JR 1.0 07-10-16 Final AF, SB, EH JR JR IV EXECUTIVE SUMMARY Executive Summary This Beach & Dune Management Plan (BDMP) for Harvey’s Towans has been produced as part of the Cornwall Beach & Sand Dune Management Project commissioned by Cornwall Council in 2015. The BDMP has two purposes: 1. Identify the best management approach; in terms of monitoring and intervention (when trigger levels are reached) requirements for the beach and dune system at Harvey’s Towans; based upon the best practice framework developed as part of the Cornwall Sand Dune and Beach Management Strategy produced by Halcrow in 2009, and updated as part of developing the new BDMPs by CH2M in 2015 (see Appendix A). 2. Provide a long-term (50 year) approach to beach and dune management at Harvey’s Towans that is based upon an up-to-date understanding of the beach-dune system and coastal processes at the site, as well as predictions of future coastal evolution. For background information, Appendix B provides an overview of how beach-dune systems work. This BDMP report provides: • An introduction to the project and BDMP (Section 1); • A summary of the characteristics (Section 2) and coastal process drivers at Harvey’s Towans (Section 3); and • Discussion and definition of suitable management techniques to apply at Harvey’s Towans, including a plan of action and the recommended monitoring and response programme (Section 4). The key issues to be addressed by beach and dune management activities include: • Potential for dune erosion during storm events. • Uncontrolled public access within the dunes resulting in dune erosion and trampling and littering. • Limited funding to undertake management activities. • Planning for adaptation of backshore assets in the future. • Lack of information / data relating to beach and dune levels and BAP habitats to inform management. • Consideration of environmental impacts on designated features. • Control of non-native invasive species within dune vegetation. • Partnership working to achieve sustainable management. • Ensuring future management practices do not impact on the Wave Hub cable. Management at Harvey’s Towans must encompass the management of both the natural pressures of wind and wave erosion and the pressures caused by human activity. Visitors to the dunes need to be encouraged, as tourism forms the main basis of the local economy, but visitors must be managed to minimise the damage to the dunes which attract them. V SECTION 1 – INTRODUCTION Introduction 1.1 Project Background Many of the sand dunes and beaches around Cornwall’s