Offshore topics

The North Falls PEIR assesses a wide range of potential impacts for physical, biological and human environmental topics for the whole project lifecycle. This page takes a high-level look at the key topics that are relevant to the offshore element of the project.

For full details on each of the specific offshore topics you can click on the relevant chapter link opposite.

Download offshore map

Marine geology, oceanography and physical processes

Boat-based geophysical and benthic surveys and desk-reviews of available data were undertaken to assess impacts on marine geology, oceanography and physical processes such as changes to suspended sediment concentrations, changes in seabed level, interruptions to bedload sediment transport and indentations on the seabed. Mitigation will be incorporated into the project design where practicable: including effective and strategic turbine spacing, piling instead of drilling and micro-siting, and burying cables.

Above: Seabed survey

Marine water and sediment quality

The surveys mentioned above also enabled assessment of potential increases in suspended sediment and the potential deterioration of water quality due to the release of existing contaminants. Through the commitment to use best practice techniques to reduce the likelihood of any accidental release of pollutants the project is predicted to have no significant impact on marine water and sediment quality.

North Falls' seabed sampling and intertidal surveys, as well as desk-based research, specifically identified habitats or species in the Kentish Knock East Marine Conservation Zone (MCZ) which overlaps North Falls' southern array area and the Margate and Long Sands Special Area of Conservation (SAC), south of the offshore cable corridor. Impacts identified include: temporary physical disturbance, increased suspended sediment concentrations, re-mobilisation of contaminated sediments and underwater noise and vibration. Mitigation incorporated into the project design, such as selection of export cable route and cable burial, means effects would not be significant, even when cumulated with other projects. As well as the relevant PEIR chapter, more can be read on the SAC in the Report to Inform Appropriate Assessment and MCZ Assessment.

Above: Fugro Mercator survey vessel

North Falls undertook 24 monthly digital aerial surveys flown along transects across the array site plus buffer zones to record existing bird populations. The impacts assessed for the project include direct disturbance, displacement, collision risk and indirect effects on prey species and habitat. Mitigation measures include sensitive site selection of the offshore cable corridor to minimise overlap with the Outer Thames Estuary SPA, and a minimum air gap of 27 metres (five metres above the gap proposed in the North Falls Scoping Report) to reduce the risk of collisions, and a best-practice shipping protocol which may include actions such as designing transit routes to minimise disturbance within the SPA, restricting and minimising vessel movements, avoiding over-revving of engines and crew training.

Through the use of mitigation measures, the project should not have significant effects on ornithology, even in cumulation with other projects except for some specific species such as the kittiwake and black-backed gull, where there may be a significant impact in terms of collision risk.

Above: Common seagull

Assessments have identified the project is likely to have a number of potential impacts on commercial fisheries such as loss or restricted access to fishing grounds; displacement of fishing activities into other areas; increased sailing times; interference with fishing activities, and safety issues for fishing. Ways these will be dealt with include the appointment of a fisheries liaison officer for the duration of the construction phase and development of a Fisheries Liaison and Coexistence Plan detailing the approach to liaison with fisheries stakeholders, and development of a Code of Good Practice for project vessels.

In terms of the project design there is a commitment to bury subsea cables, with cable protection to be used where this is not possible, Cable protection will be designed to minimise potential risk of gear snagging and the locations of protected cables will be shared.

Above: Fisheries survey

This refers to such issues as ship or plane wreck sites, or marine geophysical anomalies of archaeological interest, which were assessed during a marine geophysical survey in 2021, alongside desk-based research. Potential impacts related to direct (physical) impacts to known and also to potential heritage sites, as well as indirect impacts to the heritage assets and seascape character for example, changes to physical processes. There are no known sites within the study area that are subject to statutory protection. North Falls will use archaeological exclusion zones or minor siting adjustments as mitigation with full details on the proposed approach, and investigation into the final design of North Falls, to be covered in an Outlined Written Scheme of Investigation (WSI).

Above: Sunken passenger ship Mecklenburg

Aviation and radar assessments focussed on potential impacts to civil and military radars for example due to: the height of construction vessels, the creation of an aviation obstacle environment causing permanent interference, or increased air traffic in areas related to wind farm activity. The project will use obstacle location charts in aeronautical documents, marking and lighting turbines and application of minimum separation distances, as well as targeted communication, to ensure there are no significant impacts.