2fc4d6e8de2cf06687d7f81463b97375 English series Matthew Jeans Vattenfall Wind Power Ltd matthew.jeans@vattenfall.com pointOfContact 2024-10-02 MEDIN Discovery metadata standard 2.3.8 urn:ogc:def:crs:EPSG::4326 2024, Natural Power Consultants Ltd, Thanet Offshore Wind Farm, Benthic Survey 2024-06-24 publication 2024-06-24 revision MSE-TCE-131-4051 Within the Environmental Statement (ES) for the development of the Thanet OWF, Thanet Offshore Wind Limited committed to undertaking three post-construction monitoring surveys over a ten-year period to help ascertain impacts of the wind farm during the construction and operational phases, or longer-term changes from those recorded pre-construction. In addition, post-construction surveys would help to provide further information where uncertainty remained and test predictions made in the ES. A FEPA Licence was granted for the construction and operation of the project in 2006 and was subsequently converted to a Marine Licence in 2013 (L/2013/00011/14), for which the accompanying Annex 1 described the requirements for post-construction benthic surveys as required under Marine Licence conditions 3.1.8 and 3.1.9. In line with Licence requirements, a Post-Construction Environmental Monitoring Plan (PCEMP) was produced (Thanet Offshore Wind Farm Limited, 2010) and agreed with the MMO which set out the survey programme and objectives for all post construction monitoring. The survey programme confirmed that changes would be monitored over a ten-year period, with surveys being undertaken in years one, five and ten following the completion of construction (2012, 2017 and 2022 respectively). The second post-construction monitoring survey (originally due in 2017) was completed in 2019, and the Licencing Authority has indicated that in order for Thanet Offshore Wind Limited to remain compliant with consent conditions, the third post-construction monitoring survey was then completed in in 2022. The objective of this third post construction survey is the assessment of any long-term changes in the benthic ecology resulting from the construction and subsequent operation of the OWF. This report details the findings of the third and final post-construction monitoring survey, completed in September 2022 and a comparison of results across pre-construction monitoring and all post-construction monitoring years. Natural Power Consultants Consultant sayhello@naturalpower.com originator The Crown Estate +44 020 7851 5000 16 New Burlington Place London W1S 2HX enquiries@thecrownestate.co.uk custodian notPlanned Database Marine Environmental Data and Information Network NDGO0005 Habitats and biotopes Oceanographic geographical features Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Zoobenthos taxonomic abundance Habitat extent Habitat characterisation Suspended particulate material aggregates Benthic primary production SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision https://www.marinedataexchange.co.uk/content/info/terms-of-use otherRestrictions Publicly Available English biota oceans biota Charting Progress 2 Sea Areas 2009-06-18 creation Southern North Sea SeaDataNet vertical extent keywords 2010-01-01 revision bathybenthic 1.5695 1.6878 51.4026 51.4607 2022-09-08 2022-09-11 http://www.marinedataexchange.co.uk/ Marine Data Exchange A link to the general host site series MEDIN data guideline for sediment sampling by grab or core for benthos 2011-02-02 publication See the referenced specification true MEDIN data guideline for video surveys of species and benthos. 2018-01-23 publication See the referenced specification true To allow for a full comparison between survey campaigns, benthic grab sampling stations were selected to mirror those surveyed during the first post-construction survey in 2012 (Figure 3.1). A total of 20 sampling stations within the array and five reference stations outside the array were sampled, in line with the sampling regime of 2012 and 2019. Triplicate grab samples (as per agreement with MMO on the second benthic survey scope - discharged on the 21/10/2019 document reference number 33119/051108/R10.1) were obtained from each station, depending on the situation. Prior to the grab being deployed at each station, a drop-down video (DDV) system was used to obtain seabed imagery to ensure that the grab was not deployed on any potential S. spinulosa aggregations. This also allowed for the epibenthic community to be characterised at each location. Data was analysed alongside all previously collected comparable data in order to evaluate the change over time from baseline to the current post-construction phase. This entailed: Infauna analysed to species level in accordance with the NMAQC protocol (Wordsfold et al., 2010); PSA (and TOC) with comparable fractionation to that undertaken during baseline, 2012 and 2019; Video and still images to be reviewed, processed and analysed in accordance with national guidelines; Turner et al., (2016), standards for analysis in Visual Seabed Surveys (BS EN 16260:2012) and Coggan et al., (2007); and Reefiness assessment for any Sabellaria aggregations observed during the DDV survey (Turner et al., 2016, Gubbay, 2007; Irving, 2009; Golding et al., 2020). Prior to any statistical analysis, all data was collated in excel spreadsheets and made suitable for statistical analysis through the assignation of factors which included project phase and location as treatment groups. The names of species recorded during pre-construction (EIA) characterisation were checked for any taxonomical changes on the WoRMs database and amended. In order to undertake full and comprehensive statistical analysis between phases, species recorded as present were assigned an abundance value of one and species identified as juveniles remained as such for the analysis. Sampling stations surveyed in triplicate were treated as individual samples and were not aggregated.