Installations
Pontoon & Dock Presents
The Pontoon & Dock team has recently returned from Rotterdam where we gave two specific presentations for PRISMA (Promoting Integrated Sediment Management).
This conference was established to discuss current and innovative sustainable dredging and treatment techniques for inland water-ways. PRISMA is an initiative intended to develop and test adapted methods of dredging, treatment of dredge spoil and to develop beneficial reuse opportunities through field trials and pilot projects. It is part funded by the European INTERREG IVA “2 Seas” Cross border cooperation programme 2007–2013. The project partners of PRISMA are Waterwegen en Zeekanaal NV (Belgium), Broads Authority (UK), Hoogheemraadschap van Schieland en de Krimpenerwaard (Netherlands) and Ecole Mines de Douai (France).
This technical conference was organised for managers of governmental and non-governmental organisations in the field of dredging, aggregates, land and water management and dewatering across the partner countries and was attended by representatives of all three partners. Presentations were given by companies from Belgium, Holland, the USA and Germany and The Pontoon & Dock Company (UK) represented IMS Dredge and its Versi-Dredge self-propelled dredger and Tri-flo dewatering systems.
PRISMA aims to develop and stimulate improved techniques in dredging with the final process for sediment being re-use rather than storage or disposal. This will result in better and more environmentally friendly removal.
In its presentations, Pontoon & Dock were able to show the benefits of the IMS Versi-Dredge cutter-suction dredger which provides for a low-turbidity dredge and the pumping of high volumes of dredged material to distant disposal or re-use sites. Pumping is, of course, the most cost-effective and environmentally-friendly method of moving dredged material. The Tri-flo Dewatering System system, which was also presented to the conference by Pontoon & Dock, provides for the removal of dredged material from the water and its subsequent production as sorted, dried material – thus it is possible to produce re-usable material, such as garden compost, building sand etc. Tri-flo can handle many thousands of gallons/litres of water per minute fed directly from a dredger and can therefore produce tons of dry material per day.
The Versi-Dredge’s primary use is in dredging marinas, lakes and rivers. In these environments it is demonstrating its value in helping to alleviate the effects of flooding.
The dredge can also be used to tackle dredging projects in many other environments. The Versi-Dredge has been successfully used to remove many other products including:
- aquatic weeds
- sand
- fly and bottom ash
- coal fines
- rock flour and mine tailings
- mud and silt
- paper mill and municipal sludge
- lime and alum sludge.
7012 Versi-Dredge used to dredge Auginish Alumina Storm Water Pond on Aughinish Island,
County Limerick
This contract involved removal of approximately 40,000m3 of
soft contaminated mud from a settlement pond, and delivery to a
long term storage pond at approximately 700m distance. The
material was excavated at depths of 2.5 to 5m and was severely
caustic, therefore extensive Health and Safety Procedures were
implemented to safeguard personnel working in this
environment.
The principal plant employed by L&M Keating Ltd was their Versi-Dredge
7012 self propelled cutter-suction dredging machine.
In order to minimise disturbance of the caustic sediment the
Versi-Dredge's unique star wheel drive was not used, and
instead the machine travelled along a wire rope tensioned across
the pond.
Deliveries of up to 2000m3 per day were achieved, pumping the
material through a 300mm diameter delivery line to the receiving
pond.
7012 Versi-Dredge used to dredge Foynes Yacht Club in County Limerick
L&M Keating Ltd used their Versi-Dredge 7012 to move
approximately 6000m3 of mud from pontoon berths at Foynes
Yacht Club on the Shannon Estuary. The dredging work took
approximately one week to complete.
7012 Versi-Dredge used in Inishbofin coastal protection works and pier improvement works in County Galway
This project consists of the construction of a 300m long retaining
wall in precast and in-situ concrete, the dredging of
approximately 30,000m3 of silt, sand and gravel which will be
placed behind the concrete retaining wall and the formation of a
slope between the top of the wall and the top of the existing
cliffs. The work is topped off ith a precast revetment surface,
and improvement works was carried out to the existing quay,
including provision of a new slipway.
Because of the location of the project on an offshore island,
significant logistical obstacles must be overcome, including
extensive off site precasting, on site concrete production, and
restricted plant availability. The dredging element is heavily
restricted by environmental considerations, which impose severe
limitations on the methodology to bring the dredged material
ashore.
To execute this piece of the work L&M Keating Ltd acquired a Versi Dredge
7012 and it is intended that the dredge material will be pumped
ashore from the floating plant.
The existing ‘new’ pier is also presently being refurbished. Works
involved include installation of a sheet-piled wall around the
existing pier which will be tied into the existing structure. This
will then be infilled with dredged material and a new concrete
deck and steps constructed.
IMS Dredger features in an article on coping with flooding
The IMS Dredge was featured in an article in the Borneo Times on how dredging can alleviate flooding. Read this article.
Cutter-suction Versi-Dredge 5012HP dredger removes the need for offshore disposal
Every marina operator faces the ongoing challenge of the need to dredge their basin to maintain serviceable navigation depths, and whilst the frequency of dredge-campaigns is a symptom of the morphology, geology and local tidal, estuarial or waterway constraints, the inevitable need to dredge is a fact of life. Principally the deposition of sediments occurs where the behaviours of the water body change, a sheltered, calm, deep basin is an ideal silt trap for the million of tonnes of semi-fluid ("suspended") sediments that are present within our catchments in the UK.
The largest single cost and risk to any dredging-campaign is the disposal of the materials generated, whether it be the risk of weather delays as the contractors cannot journey to the licensed offshore disposal site in heavy seas, or the astronomic costs of disposal of materials to landfill or agriculture. Thus, the key to an economic dredging contract is the early identification of the most cost-effective/lowest risk disposal route.
"The influences here can have several magnitudes of cost effect on a project" explains Mike Ridding, Regional Contracts Manager for Land and Water Services Ltd, national Dredging Contractors. "Dredging contaminated sediments can cost £5-9/m3 to dredge, £15-45/m3 to pre-treat and a further £20-85 per m3 to transport and dispose of depending on material types, whereas conventional offshore disposal of unpolluted materials to a licensed site can be £7-15/m3 and cutter-suction dredging considerably lower again, the variances are colossal".
A 7012 HP Versi-Dredge is used at Marina Del Rey near LAX International Airport
 A 7012 HP Versi-Dredge has been put to good use at Marina Del Rey near LAX International Airport. The majority of the project was sand removal from the Marina channel but the massive amount of trash deposited by years of tourists and boaters visiting the area has now been cleaned from the channel creating a safer environment for the many species of fish and birds that inhabit the area.
The Environment Agency and Versi-Dredge
The Environment Agency has recently contracted Versi-Dredge to work on the River Thames near Oxford. Once this dredging work has been completed, the dredge’s next task will be to create some lakes. The spoil will be used as landfill for a new housing project in the Cotswolds.
Versi-Dredge installation at Cotswold Water Park
These pictures show a 5012 Versi-Dredge being delivered to the Cotswold Water Park. The dredge will be used to open up a new lake as part of a new leisure housing development.
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