Developing the seabed: resource extraction and energy development at sea

Many underwater cultural heritage sites, especially however prehistoric (now submerged) landscapes, are impacted by the extraction of sand and gravel. Flint stones and bones are recovered in a go, when the minerals are extracted. 

Developing the seabed in a way that facilitates the protection and research of underwater cultural heritage depends on the collaboration between academia and industry. The seabed is increasingly exploited by extractive industries.

Though these industries are becoming regulated under national and international frameworks, in order to reconcile interests while protecting the sea bed, cultural sites need better monitoring, inventory and accurate data flow. Information about fragile heritage on the seabed is also needed in planning other marine activities such as cabling, dredging, fish farming, extracting gravel, laying pipelines, and renewable energy platform building.

Some examples for consideration below:

The consideration of archaeological sites in oil and gas drilling operations

In the United States, permits are given to Gulf of Mexico oil and gas industry operators pending archaeological assessments conducted by the Bureau of Ocean Energy Management (BOEM). For a presentation on common methods used in assessing the potential presence of submerged archaeological resources and the oil and gas industry activities with the potential to impact underwater cultural resources, click here (text) or here (presentation).



Offshore renewable energy development - wind farms in the North Sea

Marine renewables are starting to become a substitutes for fossil fuels used for large-scale energy generation. Technologies intended to harness waves and tidal currents are being developed, but the main focus of effort in the short to medium term is on the installation of very large wind turbines offshore, often in extensive ‘parks’ or ‘farms’.

Wind farms present particular challenges to underwater cultural heritage. The turbines themselves require foundations that may be relatively extensive or penetrate deep below the seabed. Large amounts of cabling are required between the turbines and sub-stations out at sea. Very long export cables have to be installed between the farms and their landfalls. Excavation at the landfall and onshore where connections are made to national power transmission networks can threaten coastal and on-land cultural heritage. The turbines may have visual impacts on coastal monuments, and on appreciation of historic landscapes and seascapes. There can also be diverse indirect and secondary impacts on cultural heritage from the planning and construction of such massive engineering works.

For more information in the processes involved in the proposed development of offshore wind farms in the Dutch sector of the North Sea, click here.

The Nord Stream Baltic pipeline and underwater cultural heritage

A decade ago, few monuments were known in the Swedish Exclusive Economic Zone (EEZ) of the Baltic Sea. Since then, development projects have become more common and technical development has made it possible for anybody to search for, and to dive on, deeply located shipwrecks. The result is an increasing number of very well preserved shipwrecks in the EEZ. However, monuments in the Swedish EEZ don’t have the same strong legislative protection as monuments in territorial waters.

There is general public support, as well as support among policy makers, for stronger protection of the cultural heritage of the Swedish EEZ, especially since many shipwrecks has proven stunningly well preserved and scientifically valuable. This, in combination with the unclear legal scope of heritage protection within the EEZ, and activities that may threaten the cultural heritage has resulted in management practices that are new and different to practices in the Swedish territorial waters.

Find more information on a case study of the Vasa Museum, here.



The significance and contribution of marine aggregates

Marine aggregates off southern Britain commonly originated in fluvial environments during phases of lower sea level in the Quaternary Period. Aggregate extraction from such fluvial terrace and channel infill deposits has revealed evidence for low sea levels, including faunal remains, peat deposits and, most significantly, flint hand axes. In addition, more recent maritime and aviation remains are occasionally recovered in aggregate cargoes, including timbers, cannon balls and wartime aircraft parts. Artefacts found either in dredged cargoes or at the receiving wharf or other landing point are recorded through a reporting protocol agreed between BMAPA and English Heritage (EH). This involves the participation of dredger crews, wharf and processing plant staff, industry management, archaeological specialists and officials in English Heritage. The protocol, underpinned by a partnership between BMAPA and EH, a joint Guidance Note and a high standard of archaeological investigation and feedback on finds, has been and continues to be a great success.

For more information, you can consult this paper and this presentation.

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