 Portland Bypass
Port of Portland Sand bypassing
The Sand Shifter system was first commercially proven in the Port of
Portland Sands Bypassing System where it was adopted to dredge the harbour
entrance as well as provide a fixed sands bypass system for the ongoing
transfer of littoral drift sand on a long term basis.
The system recovers sand from a trap 60 metres offshore on the eastern
side of the Main Breakwater. The sand is pumped under the entrance and
discharges 3 km North of the harbour at Anderson Point.
The system is normally operated weekly to transport accumulated sand. The
fixed pumping equipment is electrically driven and is installed in two
containerised pump stations on the main breakwater.
Fully Automatic System
The system is automated using a programmable logic controller (PLC) and
personal computer for operation.
Sand production rates are continuously metered via the use of a flow
meter and densitometer. Production capacity is 70 - 150 cu.m of in-situ sand
per hour.
The harbour crossing pipeline is fully welded, heavy wall steel. It is
entrenched under the main shipping channel. Cathodic protection is by
sacrificial anodes at each end of the pipe. The on-shore pipeline is medium
density polyethylene.
click on images for larger
view
|
