Bennett Associates, M & E Consultants to the public services
Department of the State of Jersey.
Bennett Associates’ expertise has been put to good use in the
design and project management of a large proportion of a flood relief scheme,
formally known as "The Weighbridge to Town Centre, St Helier Surface Water Link
and Storage Tank", constructed in Jersey.
The purpose of the scheme was to relieve the situation when in
times of heavy rainfall the sewerage system became overloaded, resulting in the
flooding of properties in St Helier. In addition, during heavy rainfall, diluted
foul sewage also overflowed to sea before it reached the sewage treatment works
at Bellozanne.
The project was approved in 1993 and included a 25000m3 capacity
cavern, excavated by drill and blast in The Fort Regent granite rock intrusion
at St Helier.
The cavern is accessed from an existing surface car park by
underground roadway and shaft as well as having an emergency egress shaft.
Once the project was completed, overflows from the existing
combined sewerage system weirs were conveyed via two pipes located within
surface water syphon tunnels and discharged into the cavern.
Automatic level sensing and discharge pumping enables the stored
effluent to be pumped from the cavern back into the existing sewerage system
automatically as sufficient capacity becomes available downstream.
In addition to the discharge pumping system and in order to prevent the release
of noxious gases, a comprehensive system has been designed by Bennett
Associates. This system includes automatic wall and walkway cleansing,
ventilation and discharge gas odour control. To avoid the problems of corrosion
virtually all the walkways, stairways and much of the pipework within the cavern
is manufactured from Glass Reinforced Plastic (GRP) materials.
Bennett Associates designed the scheme in conjunction with the
Jersey PSD and Geo-Engineering/Donaldson Associates, the project Civil
Consulting Engineers. Bennett Associates prepared a detailed reference design
together with a technical specification. Commercial and contractual aspects of
the specification were prepared with assistance from Faithful & Gould, the
international Quantity Surveyors.
For more information, contact us on 01709-373782
|