Ecological Surveys of Welsh Lakes 2015 Goldsmith, B., Turner, S., Shilland, E. and Goodrich, S. ENSIS Ltd. London NRW Evidence Report No. 145 Date www.naturalresourceswales.gov.uk About Natural Resources Wales Natural Resources Wales is the organisation responsible for the work carried out by the three former organisations, the Countryside Council for Wales, Environment Agency Wales and Forestry Commission Wales. It is also responsible for some functions previously undertaken by Welsh Government. Our purpose is to ensure that the natural resources of Wales are sustainably maintained, used and enhanced, now and in the future. We work for the communities of Wales to protect people and their homes as much as possible from environmental incidents like flooding and pollution. We provide opportunities for people to learn, use and benefit from Wales' natural resources. We work to support Wales' economy by enabling the sustainable use of natural resources to support jobs and enterprise. We help businesses and developers to understand and consider environmental limits when they make important decisions. We work to maintain and improve the quality of the environment for everyone and we work towards making the environment and our natural resources more resilient to climate change and other pressures. www.naturalresourceswales.gov.uk Page 1 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 2 Report series: NRW Evidence Report Report number: 145 Publication date: February 2016 Contract number: 00058 Contractor: ENSIS Ltd. Environmental Change Research Centre, UCL, London. Contract Manager: B. Goldsmith Title: Macrophyte Surveys of Welsh Lakes 2015 Author(s): Goldsmith, B., Turner, S., Shilland, E. and Goodrich, S. Technical Editor: Tristan Hatton-Ellis Peer Reviewer(s) Tristan Hatton-Ellis Restrictions: None Distribution List (core) NRW Library, Bangor 2 National Library of Wales 1 British Library 1 Welsh Government Library 1 Scottish Natural Heritage Library 1 Natural England Library (Electronic Only) 1 Distribution List (others) Nicola Broadbridge, NRW Bob Edwards, NRW Sally Ellis, NRW Richard Facey, NRW Carol Fielding, NRW Tom Harrison, NRW Jenny Higgins, NRW Emyr Humphreys, NRW Dave Johnston, NRW Melissa Lacan, NRW Claire Liversage, NRW Graham Motley, NRW John Ratcliffe, NRW Graham Rutt, NRW Paul Williams, NRW Ian Hawkins, RSPB Jo-Anne Pitt, Environment Agency Lizzie Wilberforce, Wildlife Trust of South and West Wales Chris Wynne, North Wales Wildlife Trust Recommended citation for this volume: Goldsmith, B., Turner, S., Shilland, E. & Goodrich, S. 2016. Ecological Surveys of Welsh Lakes 2015. NRW Evidence Report No 145. 25 pp, Natural Resources Wales, Bangor www.naturalresourceswales.gov.uk Page 3 Contents 1. Crynodeb Gweithredol .................................................................................................... 9 Executive Summary ............................................................................................................. 10 2. Introduction ................................................................................................................... 11 2.1. Background .......................................................................................................................11 2.2. Aim of the Report ..............................................................................................................11 3. Methods ........................................................................................................................ 12 3.1. Sites ..................................................................................................................................12 3.2. Aquatic Macrophyte Surveys – JNCC ..............................................................................12 3.3. Physico-Chemical Survey and Other Data Sources .........................................................14 3.4. Bathymetric Survey ...........................................................................................................15 4. Survey Results and Metrics. ......................................................................................... 16 4.1. Lake metrics ......................................................................................................................16 4.2. Site Overviews ..................................................................................................................16 4.2.1. Ysceifiog Lake ................................................................................................................16 4.2.2. Llyn Cwellyn 34002 ........................................................................................................18 4.2.3. Llyn Cwmffynnon 33974 .................................................................................................21 4.2.4. Llyn Arenig Fawr 34864 ..................................................................................................24 4.2.5. Llyn Hesgyn 34531 .........................................................................................................26 4.2.6. Llyn Hiraethlyn 34928 .....................................................................................................28 4.2.7. Llyn y Garn 34895 ..........................................................................................................31 4.2.8. Ffynnon Lloer 33736 .......................................................................................................33 4.2.9. Llyn Hîr 34928 ................................................................................................................35 4.2.10. Llyn y Gader ...................................................................................................................37 4.2.11. Llyn Nantlle Uchaf...........................................................................................................39 4.2.12. Llyn Dinam ......................................................................................................................42 4.2.13. Llyn Coron ......................................................................................................................44 4.2.14. Llyn Traffwll .....................................................................................................................46 4.2.15. Llyn Penrhyn ...................................................................................................................49 4.2.16. Llyn Glasfryn ...................................................................................................................51 4.2.17. Llangorse Lake ...............................................................................................................54 4.2.18. Kenfig Pool .....................................................................................................................57 4.2.19. Llandegfedd Reservoir ...................................................................................................60 4.3. Bathymetric Surveys .........................................................................................................62 4.3.1. Llyn Nantlle Uchaf...........................................................................................................62 4.3.2. Llyn y Gader ...................................................................................................................63 4.3.3. Bathymetric data .............................................................................................................64 5. References ................................................................................................................... 66 6. Appendices ................................................................................................................... 68 6.1. Appendix I: Aquatic species data for all sites ...................................................................68 6.2. Appendix II: Data Archiving ...............................................................................................72 www.naturalresourceswales.gov.uk Page 4 6.3. Appendix III: Structure of Bathymetric Data ......................................................................73 6.3.1. Folder structure for bathymetric maps ............................................................................73 6.3.2. Bathymetric data folders .................................................................................................73 www.naturalresourceswales.gov.uk