Van Oord wins contract to dredge Devon estuary

Van Oord has been awarded a contract to carry out dredging works in the Kingsbridge and Salcombe Estuary in South Devon (Kingsbridge Gazette).

The works will commence later this month (Jan 2016) after Van Oord was awarded the contract to undertake maintenance dredging, following a competitive tendering process.

The Kingsbridge and Salcombe Estuary is unusual because it has no large river feeding it, just a series of small streams rising at springs some 140 metres above sea level.

The estuary is tidal up as far as Kingsbridge five miles inland. Like other South Devon estuaries, the original deep river valley has been inundated by later sea level rise, with the tide flooding in to create a wide expanse of water.

The works will be carried out utilising Van Oord’s newest dredger ‘Borr’, a water injection dredging vessel almost 14m in length and more than 5.8m wide.

Water injection dredging involves pumping water into the sediment on the estuary floor, lifting it and allowing tides and other natural forces to disperse it  into a high energy environment. It is a proven technique for small-scale dredging or working at locations that are difficult to reach.

It is expected that more than 10,000 cubic metres of silt will be shifted over a number of outgoing tides to significantly improve safety of navigation in the main dredged areas. The dredging should take between one to two weeks to complete, weather permitting.

Borr, Van Oord’s 12th water injection dredging vessel (pictured above), can dredge to a depth of 14m. Developed with a special focus on ergonomics and economics, it can be transported by road and is equipped with a multi-purpose unit for a cutter system, various grabs or pile drivers.

19 January 2016