TY - RPRT
TI - London Array Offshore Wind Farm Year 1 Post-Construction Monitoring Report
AU - MarineSpace Ltd
AB - MarineSpace Ltd was commissioned by London Array Ltd to undertake a post-construction Annual Monitoring Report (AMR) for the London Array Offshore Wind Farm (OWF). The London Array OWF is located approximately 20 km from the Kent and Essex coasts, on, and between two subtidal sandbanks, Long Sand and Kentish Knock in the outer Thames Estuary.The post-construction AMR summarises the findings of the Year 1 post-construction monitoring surveys that have been conducted within the London Array OWF study area, consisting of the OWF site and along the export cable corridor. The monitoring survey reports that have been summarised within this report are attached as appendices to this document. The monitoring report focusses on the delivery of Marine Licence conditions relevant to post-construction monitoring requirements. The report also addresses specific issues identified as requiring further assessment, or analysis, during future post-construction monitoring surveys. Future monitoring will occur for all receptors and this will provide more detail from which further conclusions can be drawn.The bathymetric surveys reviewed within this report were conducted along the export cable and within the OWF site in 2013 and 2014, consisting of multibeam bathymetry and sidescan sonar data. A number of areas of interest were identified during the surveys, most noticeably the BritNed Cable Crossing, where increased levels of scour have occurred, resulting in cable free-spans. However, since the surveys have been conducted a marine licence has been granted for cable protection and scour remediation works, with these works being completed in Q4 2014. Scour has also been observed at all wind turbine foundations surveyed, with the degree of scouring at some turbine foundations exceeding predictions assessed within the Environmental Statement. However, there have been no cumulative interactions of scour pits observed between contiguous turbine foundations. Currently the effects are discrete, with no spatial overlap.The post-construction monitoring survey for benthic habitats was conducted in summer 2014. Results have highlighted statistically significant differences between some tests conducted on the benthos during different project phases, and across seasons. However, given that these changes occurred across all project phases it is difficult to attribute them to the construction and operation of the London Array OWF.The aforementioned change in seabed condition associated with the scour pits does not appear to be linked to the observed changes in benthic communities. The observed changes in the benthos are considered a result of natural variation.The post-construction fish surveys were conducted within the OWF array, and at reference locations also used within the pre-construction surveys. The surveys were conducted in November 2013 and April 2014. The results of the post-construction surveys showed that there has been little change in species numbers since the 2009/2010 pre-construction surveys. Some fluctuations were observed in the presence, abundance and location of particular species, however the changes noted have been attributed to natural fluctuation. The results of the surveys suggest that there has been no statistically significant effects on fish populations within the London Array OWF.Post-construction aerial bird and mammal surveys were carried out during November 2013-February 2014. The focus of the aerial surveys was to ascertain the density and distribution of Red-throated Diver Gavia stellata within the study area. Red-throated Diver are the qualifying feature of the Outer Thames Estuary Special Protection Area within which the London Array OWF is located. Red-throated Diver are sensitive to several effect pathways associated with construction and operation of the OWF. Comparing the post-construction and pre-construction survey results/reports shows that the number (and density) of Red-throated Diver within the study area declined during the construction of the OWF. However, based on the data acquired to date, it has been observed that numbers, density and distribution are now recovering to levels similar to those recorded pre-construction. More detailed modelling will be conducted within future reports utilising subsequent monitoring data that has yet to be obtained. These data will more clearly illustrate the changes in distribution patterns of Red-throated Diver within the OWF site.Other bird species and marine mammals were also recorded during the aerial surveys. There has been a slight decrease in the number of Gannet recorded, and the numbers of Cormorant and Shag have increased, but these changes are not thought to have a negative effect overall on population levels associated with the study area.The overall conclusion of the report is that the physical and biological changes observed in the post-construction monitoring surveys are typical of changes observed at other OWF sites and in-line with the EIA predictions. Based on the data collected to date, no statistically significant effects have been identified that are attributable to the OWF. Future monitoring will be conducted to provide a clear illustration of any changes within the study areas.
DA - 2015/05//
PY - 2015
SP - 78
PB - MarineSpace Ltd
UR - https://www.marinedataexchange.co.uk/details/TCE-1007/2013---2015-marinespace-ltd-london-array-year-1-post-construction-monitoring-report/packages/4178?type=Report&directory=%2F
LA - English
KW - Wind Energy
KW - Fixed Offshore Wind
KW - Birds
KW - Fish
KW - Marine Mammals
KW - Physical Environment
ER -