Kriegers Flak Offshore Wind Farm
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Kriegers Flak Offshore Wind Farm Benthic Flora, Fauna and Habitats EIA - Technical Report June 2015 a Energinet.dk This report is prepared for Energinet.dk as part of the EIA for Kriegers Flak Offshore Wind Farm. The report is prepared by MariLim in collaboration with NIRAS. www.niras.dk Kriegers Flak Offshore Wind Farm Cable corridor Kriegers Flak Kriegers Flak Offshore Wind Farm Baseline and EIA report on benthic flora, fauna and habitats Client NIRAS for ENERGINET DK Tonne Kjærsvej 65 7000 Fredericia Contractor MariLim Aquatic Research GmbH Heinrich-Wöhlk-Str. 14 Baseline/EIA study 24232 Schönkirchen Dipl. Biol. T. Berg, K. Fürhaupter, H. Wilken & Th. Meyer 2 Kriegers Flak OWF: Baseline & EIA report on benthic flora, fauna and habitats Date: June 2015 Version: Final Authors: Torsten Berg, Karin Fürhaupter, Henrike Wilken, Thomas Meyer Kriegers Flak OWF: Baseline & EIA report on benthic flora, fauna and habitats 3 Content 1 Non-technical summary ............................................................................................................... 7 2 Introduction .................................................................................................................................. 8 3 Technical project description .................................................................................................... 10 3.1 General description ....................................................................................................... 10 3.2 Turbines ......................................................................................................................... 12 3.2.1 Driven steel monopile ............................................................................................... 12 3.2.2 Concrete gravity base ............................................................................................... 14 3.2.3 Jacket foundations ..................................................................................................... 17 3.2.4 Suction Buckets ......................................................................................................... 18 3.2.5 Offshore foundation ancillary features .................................................................... 19 3.3 Offshore substation at Kriegers Flak ........................................................................... 20 3.3.1 Foundations for substation platforms ..................................................................... 21 3.4 Submarine cables .......................................................................................................... 24 3.4.1 Inter-array cables ....................................................................................................... 24 3.4.2 Export cables ............................................................................................................. 25 3.5 Wind farm decommissioning ........................................................................................ 26 3.5.1 Extent of decommissioning ...................................................................................... 26 3.5.2 Decommissioning of wind turbines ......................................................................... 27 3.5.3 Decommissioning of offshore substation platform ................................................ 27 3.5.4 Decommissioning of buried cables .......................................................................... 27 3.5.5 Decommissioning of foundations ............................................................................ 27 3.5.6 Decommissioning of scour protection..................................................................... 27 4 Methods and material ................................................................................................................ 29 4.1 Definitions ...................................................................................................................... 29 4.2 Investigation area .......................................................................................................... 29 4.3 Field programme and survey methods ........................................................................ 30 4.3.1 Grab stations ............................................................................................................. 36 4.3.2 Diving stations ........................................................................................................... 38 4.4 Supplementary Data ...................................................................................................... 39 4 Kriegers Flak OWF: Baseline & EIA report on benthic flora, fauna and habitats 4.5 Analysis methods .......................................................................................................... 40 4.5.1 Species Diversity ........................................................................................................ 40 4.5.2 Abundance, biomass and shell length ..................................................................... 40 4.5.3 Habitat classification and mapping ......................................................................... 40 4.6 Assessment methods .................................................................................................... 43 5 Baseline conditions .................................................................................................................... 45 5.1 Abiotic conditions .......................................................................................................... 45 5.1.1 Kriegers Flak .............................................................................................................. 45 5.1.2 Cable corridor ............................................................................................................ 46 5.2 Macrozoobenthic communities .................................................................................... 48 5.2.1 Kriegers Flak .............................................................................................................. 48 5.2.2 Cable corridor ............................................................................................................ 52 5.3 Macrophyte communities .............................................................................................. 55 5.3.1 Kriegers Flak .............................................................................................................. 55 5.3.2 Cable corridor ............................................................................................................ 56 5.4 Benthic Habitats ............................................................................................................. 58 5.4.1 Kriegers Flak .............................................................................................................. 60 5.4.2 Cable corridor ............................................................................................................ 61 6 Description of project pressures and potential impacts ......................................................... 65 6.1 Project activities and pressures .................................................................................... 65 6.1.1 Suspended sediments ............................................................................................... 66 6.1.2 Sedimentation ............................................................................................................ 67 6.1.3 Footprint .................................................................................................................... 69 6.1.4 Solid substrate ........................................................................................................... 69 6.2 Worst case scenarios ..................................................................................................... 70 6.2.1 Suspended sediments ............................................................................................... 70 6.2.2 Sedimentation ............................................................................................................ 71 6.2.3 Footprint .................................................................................................................... 71 6.2.4 Solid substrate ........................................................................................................... 72 7 Impact assessment for the construction phase ....................................................................... 73 7.1 Kriegers Flak .................................................................................................................. 73 7.1.1 Suspended sediments ............................................................................................... 73 Kriegers Flak OWF: Baseline & EIA report on benthic flora, fauna and habitats 5 7.1.2 Sedimentation ............................................................................................................ 74 7.1.3 Footprint .................................................................................................................... 77 7.1.4 Solid substrate ........................................................................................................... 79 7.2 Cable corridor ................................................................................................................ 82 7.2.1 Suspended sediments ............................................................................................... 82