Jersey- Shaft 3 Connection

Following our feasibility study in 2007/08, we have recently been awarded the detailed design of a challenging underground connection into the existing Surface Water Link tunnel in the centre of St Helier, Jersey.

The connection will be made by a 65m long twin 1200mm ID pipejack from a new 7.0m ID secant piled shaft and include a new CSO just below street level to divert surface water into one pipejack and foul sewage into the other.

As well as the detailed design, Donaldson Associates will specify and supervise additional site investigation, prepare contract documentation, assess the main works tenders and supervise the works.

Particular challenges include :

i) ensuring that the works do not draw down groundwater from the superficial deposits and thus cause settlement to historic buildings built on raft foundations

ii) limiting the  impact on adjacent businesses, residents and the Jersey Art Centre. 

Donaldson Associates will work closely with the Transport and Technical Services Department of the States of Jersey, the client for the scheme.