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Marine unexploded ordnance, clearance and marine licensing – what developers need to know

In an effort to fulfil their UK Marine Strategy and the associated underwater noise target, the UK Government has considered new ways to clear unexploded ordnance (UXO) in the marine environment. The proposals have been compiled in an interim position statement until more robust evidence is available on the benefits of low noise alternatives to high order detonation.

The position statement was published jointly with the Department for Business, Energy and Industrial Strategy (BEIS), the Marine Management Organisation (MMO), the Joint Nature Conservation Committee (JNCC), Natural England (NE) the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED), the Department of Agriculture, Environment and Rural Affairs (DAERA), NatureScot Marine Scotland and Natural Resources Wales.

What is a UXO?

UXO can generally be considered as any type of military ammunition or explosive which has failed to detonate. Since World War I and II, a large volume of UXO has been sitting dormant in the marine environment, including:

  • sea mines;
  • torpedoes;
  • depth charges;
  • air-dropped charges;
  • artillery projectiles;
  • rockets;
  • land mines; and
  • land service ammunition (e.g., mortars and hand-grenades).

UXO is often discovered during routine maintenance surveys of offshore infrastructure, dredging activities and marine construction. However, with ever-increasing development in the marine environment, more and more UXO deposits are being discovered.

The Ordtek Mine Map has been developed as an interactive tool to display offshore UXO contamination (although it should not be relied on as complete). In particular, it pin-points various known munition dump sites, reported munitions findings, WWII British Armament Training Areas and WWI and II British/German Mining Areas.

High order detonation vs low noise alternatives

Wherever UXO is discovered, marine licences are required to authorise clearance and the method proposed to achieve this. 

High order detonation is the most-commonly used method. It involves detonating large explosive donor charges next to the UXO, causing any live explosive material in the UXO to detonate along with it. This method is criticised for causing loud underwater blasts which disturb protected marine environments.

Low noise alternatives similarly use explosive donor charges but in much smaller volumes. They result in only the donor charge itself detonating and not the UXO, thus mitigating any impact on the surrounding environment. The UXO is still rendered inert. These alternatives are now widely available to the commercial market and are encouraged to be used. There is, however, very limited robust evidence as to the effectiveness of low noise alternatives (hence the interim nature of the position statement).

What impact does this have on marine development?

Marine licence applications for UXO clearance are made to the following bodies:

All applications of this nature will require detailed impact assessment and mitigation plans, and low noise alternatives should be prioritised in accordance with the interim position statement. If high order detonation appears to be the only viable option, it should be justified within the application, and special consideration should be given in the context of Marine Protected Areas (MPAs).  

Although authorisation of UXO clearance is highly fact-dependant and considered on a case-by-case basis, it is recommended that the relevant Statutory Nature Conservation Bodies and regulators are consulted at the earliest opportunity to avoid consent delays. It is, however, recognised that this may not always be feasible e.g., where the clearance of the UXO is required urgently in the interests of immediate safety.

What can we expect for the future?

The UK Government will continue to consult widely to obtain further evidence on the effectiveness of low noise alternatives. At the time of writing, there are no updates as to whether robust supportive evidence in favour of low noise alternatives has been found, but it can be expected in due course. As a result, the consideration of low noise alternatives is likely to play a key part in the future of UXO clearance.

For more information on this article, please contact Tommy Fox.

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