Can UXO still pose a risk to construction projects in Swansea?
Swansea did not sustain as much bombing as the UK’s largest cities, although it was the most heavily bombed administrative area in Wales, with almost 1,500 recorded H.E. bombs. Much of the bombing targeted the docks and industrial areas, but the sheer quantity, combined with the inaccuracy of WWII-era bombing, meant that bombs fell across the city.
The primary potential risk from UXO in Swansea is from items of German air-delivered ordnance which failed to function as designed. Approximately 10% of munitions deployed during WWII failed to detonate, and whilst efforts were made during, and after the war to locate and make UXBs safe, not all items were discovered. This is evidenced by the regular, on-going discoveries of UXO during construction-related intrusive ground works not only in Swansea, but across the UK.
Occasionally items of British explosive ordnance are also encountered – often associated with WWII defensive measures or troop operations. Anti-aircraft batteries were stationed around Swansea, and as a major coastal city it was well-defended.
As with German bombs, some anti-aircraft shells failed to detonate and ended up in the ground, and other munitions intended for the defence of the city were sometimes disposed of through burial after the risk of invasion had passed.
I am about to start a project in Swansea, what should I do?
Developers and ground workers should consider this potential before intrusive works are planned, through either a Preliminary UXO Risk Assessment or Detailed UXO Risk Assessment. This is the first stage in our UXO risk mitigation strategy and should be undertaken as early in a project lifecycle as possible in accordance with CIRIA C681 guidelines.
It is important that where a viable risk is identified, it is effectively and appropriately mitigated to reduce the risk to as low as reasonably practicable (ALARP). However, it is equally important that UXO risk mitigation measures are not implemented when they are not needed.
While there is certainly potential to encounter UXO during construction projects in Swansea, it does not mean that UXO will pose a risk to all projects. Just because a site is located in Swansea does not mean there is automatically a ‘high’ risk of encountering UXO. It really does depend on the specific location of the site being developed.
A well-researched UXO Risk Assessment will take into account location specific factors – was the actual site footprint affected by bombing, what damage was sustained, what was the site used for, how much would it have been accessed, what were the ground conditions present etc.
It should also consider what has happened post-war – how much development has occurred, to what depths have excavations taken place and so on. This will allow an assessment of the likelihood that UXO could have fallen on site, gone unnoticed and potentially still remain in situ.