Van Oord’s water injection dredger Borr ready for Parrett job

Dredging is due to start again this week on the River Parrett, organised by Somerset Drainage Boards Consortium for Somerset Rivers Authority.

Somerset Rivers Authority

Van Oord’s water injection dredger Borr will remove silt between Saltmoor Pumping Station – just down from the Thatchers Arms where the overhead power lines cross the river.

The Borr is due to arrive at Dunball Wharf this week.

Under the project, large quantities of silt will be removed to increase the river’s capacity to carry floodwater.

Somerset Rivers Authority photo

The bed of the Parrett is characterised by fine sediments including sands, silts and clays.

The injection of water separates and mobilises these particles so they can be washed away in what Van Oord call a ‘density current’ in the lower third of the water column.

The ‘density current’ travels downriver on an outgoing tide and disperses through natural processes, usually wave action. This disruptive force breaks the bonds in the ‘density current’ and releases sediments from suspension.