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Archive for August, 2011

Chris Ansell

Friday, August 19th, 2011

Chris has a strong environmental focus with a solid understanding of all the products and services Terraqua offers: bioengineering, erosion control, geotextiles and water quality issues. Chris manages the day to day sales operations of Terraqua.

Silt Curtains at Falmouth Marina

Tuesday, August 16th, 2011

Land & Water Services had to provide a sustainable solution for a difficult and unique dredging challenge at Falmouth Marina in Cornwall.

A bespoke silt curtain was designed & manufactured 94m long by 8.4m deep, ballasted to enclose the purpose built Land & Water pontoon and thus prevent contamination leaking into the River Fowey during the dredging operation. The silt curtain weighing approx 2 tonnes was installed by a 15 men team, including 4 divers, in one day.

The marina site falls within the Fal-Helford area, a SSSI, however the site formerly occupied the Empire & Kings wharves, each more than 200m long, which were constructed in the 1930s. The wharves have now been removed and as they have not dredged since 1938 almost 10,000m3 of highly contaminated material containing heavy metals toxins such as TBT- which experts claim is the most toxic substance ever deliberately introduced into the marina environment- needs to be removed from site.

The silt being unsuitable for disposal at sea, due to the local oyster & mussel beds, is being transported in sealed lorries to the redundant China Clay workings at St Austell where, after being mixed with green waste and sewage, it will be used to landscape the former industrial site without the contamination proving to be an on-going issue. 

 See video of the dredging project.

silt curtain arriving on site

Silt curtain arriving on site

silt curtain assembely 1

Silt curtain assembely

silt curtain assembely 2

Silt curtain assembely

Weighing almost 2 tonnes the silt curtain required plenty of labour and an experienced team of divers to fully install

Weighing almost 2 tonnes the silt curtain required plenty of labour and an experienced team of divers to fully install

team work hard to make sure the silt curtain is positioned correctly.

Land & Water team work hard to make sure the silt curtain is positioned correctly.

The silt curtain is continually installed around the floating booms.

The silt curtain is continually installed around the floating booms.

The silt curtain now fully operational and the long reach excavator is ready dredge

The silt curtain now fully operational and the long reach excavator is ready dredge

The silt curtain now fully operational and the long reach excavator is dredging

The silt curtain now fully operational and the long reach excavator is dredging

The silt curtain fully operational and the long reach excavator is dredging

The silt curtain fully operational and the long reach excavator is dredging

During the summer months of 2011, over 32,000 tonnes of contaminated sediments was removed by Land & Water services from the harbour area of Falmouth marina, Cornwall

During the summer months of 2011, over 32,000 tonnes of contaminated sediments was removed by Land & Water services from the harbour area of Falmouth marina, Cornwall