Update on the Cheapside men, mud, machines & a monster mollusc!
The Land & Water Team engaged in the dredging and piling of the Cheapside Pound have been hard at work all through April.
Eucalyptus piling progressing
Land & Water’s Mike Hill explains the methodology…
“We have already installed 160 of the Eucalyptus piles. These are the heavyweight timber poles that will stabilise the base of the embankment. We have another 160 being delivered and will have used up to 480 by the end of the job.
“The piles are 4.3 metres in length. They are driven down into the bed of the canal to a depth of 3 metres. We have used an auger to start the hole in some places, whilst we have been able to drive others in using the hydraulic power of the Water King amphibious excavators. We use a chainsaw to level out any slight unevenness along the line. The final stage is to backfill behind the piles with dredged material”
Nicospan for natural drainage
An impressive line of timber and high tensile fabric is now to be seen forming the channel edge on other sections of the Cheapside Pound. See picture below.
The piling and fabric system known as Nicospan provides high-quality and economic erosion control as it stabilises the ‘toe’, or lowest point, of the embankment.
The system allows natural drainage and vegetation growth.
Nicospan is a prefabricated, double woven polyethylene revetment fabric made from strong Ultra Violet stabilised mono-filament yarn. The fabric is heat sealed to form a series of open pockets each 220mm wide to allow timber posts to be placed into the sleeve. The 3 metre long timber posts inserted into the Nicospan are smooth, machine rounded & pointed. They have also been pressure treated with an environmentally safe wood preservative.
The Nicospan poles are also installed using the hydraulic power of the 7 tonne, Water King, amphibious excavator. See photo below.
Silt settling pond created
In the meantime, natural drainage evident along the Cheapside Pound has created a slow but steady flow of very black silt moving downstream towards Wallbridge Upper Lock.
Nicospan filtration screens have been placed across the channel whilst a settling pond has been created in the canal bed to gather the result of decades of vegetation decomposing in the clogged channel.
High level skills are again being applied by the Land & Water machine operators who move the silt to the draining & drying lagoon on what was once Stroud’s coal wharf.
The ‘Black Lagoon’
The silt is poured into the drying lagoon from the excavator buckets. Recent rains may have slowed the drying process somewhat but the system does work.
After a few days the excavators are able to scoop up the black morass and place it onto a growing pile of nutrient rich material.
The Monster Mollusc from the Black Lagoon
Click here if you dare — or on the picture below, to gain a close up view of the remains of a surprisingly large freshwater mussel found in the silt.
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