Understanding cultural marine archaeology and identifying UXOs for offshore wind development

The construction of offshore wind farms requires careful consideration and understanding of cultural marine archaeology to ensure the protection of subsea environments. Additionally, the identification and mitigation of unexploded ordnances (UXOs) in these areas are crucial to ensuring the safety and success of a project. In this blog, we will explore the importance of cultural marine archaeology in offshore wind development and the methods used to identify UXOs.

Understanding cultural marine archaeology

Cultural marine archaeology focuses on studying and preserving submerged archaeological sites, artifacts, and cultural heritage found in marine environments. This can include shipwrecks, ancient settlements, submerged landscapes, and other artifacts that provide valuable insights into human history and civilization. Offshore wind development projects often intersect with these sites, requiring a thorough understanding of the potential impact and the implementation of appropriate mitigation measures. Preserving and respecting these archaeological resources ensures that future generations can benefit from the knowledge and insights they provide.

A comprehensive site characterisation assessment of the marine area conducted prior to the construction phase will – amongst other things – identify any potential archaeological sites or culturally sensitive artifacts. This involves a combination of remote sensing techniques such as side-scan sonar, multibeam bathymetry, and magnetometer surveys, which help create detailed maps of the seafloor and detect anomalies that may indicate the presence of archaeological remains.

If a potential site is identified, further investigation takes place through underwater archaeological surveys. Remotely operated vehicles (ROVs) are deployed to examine and document the site, record any findings, and determine its cultural and historical significance. These surveys provide crucial data for assessing the impact of the proposed wind farm and devising appropriate mitigation strategies to avoid or minimise disturbance to the archaeological resources.

Photo of rusty metal structure lying on sea bed

The identification and management of UXOs are vital to guarantee the safety and success of offshore wind farms.

Optimising the site investigation phase

Although geophysical results inform later geotechnical site investigations, there are significant advantages to a collaborative, integrated approach that combines geophysical and geotechnical surveys. More efficient surveys can help to deliver faster site assessments and, combined with the lower administrative burden from using a single interface, contact person and contract can help to reduce costs. Effective knowledge transfer and improved ground models can better inform geotechnical site investigation locations for de-risked, cost-effective structure designs and, ultimately, better long-term project outcomes for a lower levelised cost of energy.

Photo of rusty bomb wreck laying in the sea bed in Croatia

Image generated using Kapwing AI for illustrative purposes only

Identifying and managing UXOs

In addition to cultural marine archaeology, the identification and management of UXOs is a critical aspect of the site investigation phase. UXOs are remnants from munitions training and test sites and past conflicts, and include unexploded bombs, mines, or shells present in the marine environment. These UXOs pose risks to both the construction and operation of offshore wind farms, as well as to the safety of marine life and personnel.

While typical site-characterisation surveys are performed for permitting, siting and design of the wind development area and potential offshore export cable corridor routes, UXO surveys require a greater density of data to mitigate any risk during construction and installation. This includes tighter line spacing, and increased ping density of sensors to identify targets.

TerraSond, a geo-services brand in Acteon’s Data and Robotics division collects data, conducts analysis, and reports for as low as reasonably practicable (ALARP) UXO certification. An array of towed magnetometers identify potential targets and analysis of the data informs the quantity, type, and location of potential UXOs across the site for later identification with an ROV to determine appropriate mitigation actions.

If UXOs are found, specialised teams are engaged to assess and safely dispose of them following established protocols. This process ensures that construction activities can proceed safely.

Conclusion

Cultural marine archaeology plays a crucial role in offshore wind development by safeguarding our historical and cultural heritage. It ensures that archaeological sites and artifacts are identified, assessed, and appropriately managed, minimising any potential impact from construction activities. Likewise, the identification and management of UXOs are vital to guarantee the safety and success of offshore wind farms.

Through the integration of site characterisation surveys, offshore wind developers can strike a balance between renewable energy generation and the preservation of the subsea environment. By understanding and respecting the underwater cultural resources and addressing potential hazards, we can continue to harness the power of offshore wind sustainably and responsibly.

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