Consultancies APEM and NIRAS are to carry out pre-construction ornithology surveys for RWE’s 1400MW Sofia offshore wind farm off east England by integrating light detection and ranging (Lidar) and traditional digital aerial surveys.
The duo have been engaged by RWE to develop the project’s Ornithology Monitoring Plan.
Twelve surveys, gathering data on potentially thousands of individual birds, will be carried out over two years before offshore construction begins in late 2023.
The surveys will look primarily at kittiwakes during their breeding season although data on other bird species and marine mammals will also be collected.
Two aircraft provided by UK aviation firm Ravenair will be equipped with APEM’s combined Lidar and digital hi-resolution camera equipment to capture data and images of birds and marine mammals.
“By collecting the height data and images at the same time, individual flying birds can be matched with Lidar points, therefore recording their flight height much more accurately than via other available methods,” RWE said.
Through a remote sensing technique that uses light pulses to measure ranges, when installed on a survey aircraft, Lidar can identify the height of birds in flight to an estimated accuracy of within one metre over the sea surface, and can rapidly cover large areas of open habitat, the company said.
“This combined Lidar and digital photography method enables the recording and analysis of flight heights and direction, age classes, distribution and bird numbers, providing a wealth of information for the project and also for the wider offshore wind sector,” it added.
The team will also investigate the potential for using this technique for estimating seabird flight speeds.
All data will be made publicly available for further strategic research projects.
The two aircraft carrying out Sofia’s pre-construction surveys will fly at 450 metres altitude to minimise any risk of disturbance to the birds being measured.
They will traverse survey lines spaced two kilometres apart across the whole array area, with each aircraft will survey half of the transects to ensure the full 593km squared wind farm site is covered.
The surveys will be completed by the end of summer 2022.