Coastal Squeeze Evidence and Monitoring Requirement Review Oaten, J., Brooks, A. and Frost, N. ABPmer NRW Evidence Report No. 307 Date www.naturalresourceswales.gov.uk About Natural Resources Wales Natural Resources Wales’ purpose is to pursue sustainable management of natural resources. This means looking after air, land, water, wildlife, plants and soil to improve Wales’ well-being, and provide a better future for everyone. Evidence at Natural Resources Wales Natural Resources Wales is an evidence based organisation. We seek to ensure that our strategy, decisions, operations and advice to Welsh Government and others are underpinned by sound and quality-assured evidence. We recognise that it is critically important to have a good understanding of our changing environment. We will realise this vision by: Maintaining and developing the technical specialist skills of our staff; Securing our data and information; Having a well resourced proactive programme of evidence work; Continuing to review and add to our evidence to ensure it is fit for the challenges facing us; and Communicating our evidence in an open and transparent way. This Evidence Report series serves as a record of work carried out or commissioned by Natural Resources Wales. It also helps us to share and promote use of our evidence by others and develop future collaborations. However, the views and recommendations presented in this report are not necessarily those of NRW and should, therefore, not be attributed to NRW. www.naturalresourceswales.gov.uk Page 1 Report series: NRW Evidence Report Report number: 307 Publication date: November 2018 Contract number: WAO000E/000A/1174A - CE0529 Contractor: ABPmer Contract Manager: Park, R. Title: Coastal Squeeze Evidence and Monitoring Requirement Review Author(s): Oaten, J., Brooks, A. Frost, N. Peer Reviewer(s) Hull, S. (ABPmer), Park, R. (NRW), Rimington, N. (NRW) Approved By: Park, R., Rimington, N. Restrictions: None Distribution List (core) NRW Library, Bangor (One Electronic) 3 National Library of Wales (Electronic Only) 1 British Library (Electronic Only) 1 Welsh Government Library (Electronic Only) 1 Scottish Natural Heritage Library (Electronic Only) 1 Natural England Library (Electronic Only) 1 Recommended citation for this volume: Oaten, J., Brooks, A. and Frost, N. 2018. Coastal Squeeze Evidence and Monitoring Requirement Review. NRW Report No: 307, 188pp, Natural Resources Wales, Cardiff. www.naturalresourceswales.gov.uk Page 2 Contents Crynodeb Gweithredol .............................................................................................................. 8 Executive Summary ............................................................................................................... 18 1. Introduction ..................................................................................................................... 27 1.1. Overview ........................................................................................................................... 27 1.2. Report structure ................................................................................................................ 29 2. Project Background ........................................................................................................ 30 2.1. Shoreline Management Plans ...........................................................................................30 2.2. Defining coastal squeeze ..................................................................................................33 2.3. Sea level rise .................................................................................................................... 35 2.4. Predicted habitat losses in Wales .....................................................................................40 2.4.1. National Habitat Creation Programme ...........................................................................42 3. Calculating coastal squeeze ........................................................................................... 46 3.1. Causes of change to intertidal areas ................................................................................46 3.2. Establishing a baseline .....................................................................................................50 3.3. Calculating losses ............................................................................................................. 52 4. Review of Possible Monitoring Techniques .................................................................... 54 4.1. Introduction ....................................................................................................................... 54 4.2. Sea level ........................................................................................................................... 56 4.2.1. Overview of monitoring techniques ................................................................................56 4.2.2. Processing and analysis of data .....................................................................................60 4.2.3. Technical review .............................................................................................................61 4.3. Topography/bathymetry ....................................................................................................64 4.3.1. Overview of monitoring techniques ................................................................................64 4.3.2. Processing and analysis of data .....................................................................................66 4.3.3. Technical review .............................................................................................................67 4.4. Habitat types, boundaries and condition ...........................................................................71 4.4.1. Overview of techniques ..................................................................................................71 4.4.2. Processing and analysis of data .....................................................................................72 4.4.3. Technical review .............................................................................................................74 4.5. Summary ........................................................................................................................... 78 5. Current Monitoring and Other Relevant Data ................................................................. 80 5.1. Overview ........................................................................................................................... 80 5.2. Sea level monitoring .........................................................................................................81 5.2.1. Tide gauges .................................................................................................................... 81 5.2.2. Satellite altimetry ............................................................................................................ 81 5.3. Water Framework Directive monitoring ............................................................................82 5.4. Marine Protected Area monitoring ....................................................................................82 5.4.1. Marine Regulation 35 Habitat Features ..........................................................................83 5.4.2. Marine Article 17 Reporting Habitat Features ................................................................83 5.5. Other monitoring ............................................................................................................... 84 www.naturalresourceswales.gov.uk Page 3 5.5.1. Light Detection and Ranging (LiDAR) ............................................................................ 84 5.5.2. Multispectral imagery ......................................................................................................84 5.5.3. Hydrographic monitoring ................................................................................................85 5.6. Hydrodynamic modelling data ..........................................................................................86 5.7. Wales Coastal Monitoring Centre .....................................................................................86 5.8. Summary ........................................................................................................................... 87 6. Uncertainty ..................................................................................................................... 93 6.1. Overview ........................................................................................................................... 93 6.2. Instrument measurement uncertainty ...............................................................................93 6.3. Thematic uncertainty .........................................................................................................95 6.4. Causes of change and effects to intertidal habitat ............................................................96 6.5. Upscaling observed records of change from a local to regional scale .............................96 6.6. Using records of observed change to estimate future habitat losses ............................... 97 6.7. Statistical evaluation of overall uncertainty .......................................................................97 7. Options Appraisal Assessment ......................................................................................