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DPC Dredging Days 2008

Another First For CEDA“I am absolutely delighted that Antwerp has been chosen as the venue for CEDA DreDging Days 2008 – we’ve an exciting programme and I wish all participants a fruitful stay in our city”

Dynamic – Frederik Mink

Winner – Stephanie Janssen

Pilot projects – Frederik Roose

Stripping – Erik van Eekelen

Antwerp’s magnificent town hall hosted a reception for delegates

It’s the first time Dredging Days has been held in Antwerp, the first time it’s been organised by CEDA’s Belgian

Chapter – and with that short speech at the Elzenveld Conference Centre on 1 October, chapter and conference chairman Freddy Aerts got the show on the road, writes Tony Slinn.

First up should have been Flemish minister president Kris Peeters, who apologised for his absence but was ably represented by

Flanders’ chef de cabinet Raf Suys, who addressed the conference theme of Dredging Facing Sustainability.

“Flanders’ government is pleased that sustainability is the theme,” he said, “after all, our ports earn about €14Bn and provide 108,000 full-time jobs. But our ports operate in a very competitive environment and we must assure they remain accessible in the future.”

Dredging, he added, had a vital role to play in the

Freddy Aerts opens the conference

On message – Raf Suys

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DPCDredging Days 2008

of the project, problem solving and innovative ideas were among the benefits,” she added, “and the conclusion is that if well applied, projects can benefit from partnering.”

Understanding problems and applying an innovative approach was also the theme of John-Jack Peters’ paper Can Morphological Dredging Help Improve Natural Values in Rivers and Estuaries?

Using experience he gained working on Africa’s River Congo in the 1960s – plus 90 years of others’ research on working both with and against nature – he showed how minimal dredging in certain parts of a river could have a major impact on other areas.

Morphology was also Frederik Roose’s theme for An Alternative Dumping Strategy to Serve Sustainability in the Scheldt Estuary – “A well-considered sediment disposal strategy may contribute to morphological stability,” he said, describing pilot projects at Walsoorden in the western Scheldt and their ongoing ecological monitoring.

Which was an apt way of introducing...

session Two...whose theme was Monitoring,

chaired by Jos Smits standing in for IMDC’s Kathleen de Wit.

Jan De Nul’s Marcel Van Parys kicked

by European Dredging Association consultant Frederik Mink, who addressed Dredging and Ecosystems in EU Law.

session one“Do we know enough? Can we model

it? It’s a dynamic complex of animals and micro-organisms and their non-living environment functioning as a unit,” he said.

The ecosystem approach had posed problems for legislation/regulations, he added, as it’s “so often at odds with the environmental approach.”

Looking at major dredging projects that were specified in line with the latter – Singapore and Øresund among them – he said they’d been carried out with great care, “but they fall short of the ecosystem approach. The problem is that there’s no available ‘toolbox’ for such an approach...”

Stephanie Janssen is developing her own ‘toolbox’ via a five-part model and her presentation Conceptual Model for Partnering in the Dredging Industry won the IADC Best Paper Award – and will be featured in February’s DPC.

“Analysis of projects shows that increased involvement by contractors with clients depends on the incentives offered to the contractor,” she said, detailing two projects in Holland where partnering took place. “Optimisation

It was a poignant moment for ReweRt wuRpts, his final AGM as president coinciding with CEDA’s 30th anniversary

Looking back, highlights included seven guides produced with IADC on Environmental Aspects of Dredging, establishment of the African Section, the first Middle East conference in Qatar – “and now the first Dredging Days to be held in Antwerp.”

Handing over to new president Anders Jensen (right), Rewert commented that CEDA’s board was now looking to the future and in aiding them: “the importance of our regional chapters’ work can’t be over-emphasised.

“I’ve enjoyed the opportunity to meet so many people in our profession in such a variety of locations,” he concluded,

thanking all who’d helped him over the years.Vice-president Jos Claessens gave a formal tribute to

Rewert – you can read more about that on page 2.The AGM also saw Prof Wim Vlasblom’s final

report as treasurer, with Prof Cees van Rhee taking over, and the retirement of Jan van ‘t Hoff from the

board (see DPC Nov 08 and page two).“Thank you for trusting me with the presidency, it’s a real

honour,” said Anders. “In a changing world we have a bright future by working as an NGO with authorities such as the EU – it’s the best way to give value to our members. Delays in

project planning are unfortunately becoming the rule, not the exception,” he continued, “and CEDA will have to work hard to turn this around.”

Pledging to work with ‘sister’ organisations, such as EuDA, PIANC and the IADC, he concluded: “You cannot overestimate the importance of communities like this that enable people from all over Europe and beyond to meet and exchange experiences.”

CEDA’s AGM

Wind power – Kenneth Piere

Stable – Piet Haerens

Lagoons – Sofie Herman

Deeper – Gijsbert Van Holland

Holistic – Robby de Backer

Environmentalist – Polite Laborie

country’s future: “Our policy fits in with sustainable development and future projects, such as the €830M Flemish-Dutch deepening of the Scheldt, will see dredged material being used to benefit the environment as well as navigation.”

Antwerp University’s Prof Patrick Meire followed with the day’s keynote speech: Can Dredging Improve Ecosystem Services to Achieve Sustainability?

“Ecosystem services drill down the food chain and you’ll find that products with a high market value are often dependent on species with no market value – a sole, for example, will feed on about 70 species,” he pointed out.

Touching on how recent legislation had produced a conflict between economic and ecological development, he felt the ecosystem services concept could be the link between them. “We need an integrated approach that looks at the entire food chain,” he continued, “including measures to maintain and restore habitats – which is where the dredging industry comes in.”

Looking at projects that have created vital wetlands, he concluded: “With a good understanding of past and future development of ecosystem services, dredging can certainly improve them.”

With the Flemish government’s Youri Meersschaut in the chair, session one on Decision Processes was introduced

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“Quotes”

“When I started as a young scientist, dredgers were the enemy!” – Prof Patrick Meire

“If you are dredging without an understanding of a river’s morphology, then you are dredging blind” – John-Jack Peters

“It’s a very strange looking construction, but...engineers were not drunk when they designed it”– Marcel Van Parys on Abu Dhabi settlement ponds

“In this time of financial maelstroms, it’s my task to talk to you about turbidity!” – Jan Vandenbroeck

“A gredger – sorry, a grab dredger! Or is that going to be a new word?!” – Dr Caroline Fletcher

“There’re people in this room with ships that this project wouldn’t fill even once” – Martin Maloney on Milford Haven dredging

“Dredging is a niche business and sometimes it’s very nice to be in a niche” – Rewert Wurpts passing the presidency to Anders Jensen

off, describing the massive Saadiyat reclamation project in Abu Dhabi (see DPC April 2008) which involved about 45M m3 of dredged material.

“Compliance monitoring and remedial work included diver inspections of sea grass and coral, cleaning barnacle-encrusted turtles and even rescuing a young gazelle stranded by high water and returning it to its mother!” he told delegates.

Marseille’s ongoing Fos Terminal dredging project was Jan Vandenbroeck’s subject, the major problem being a nearby mussel farm.

“Environmental conditions included no overflow and minimal turbidity from CSDs, backhoes and hoppers,” he said. Measurements were taken by sensor every 10 minutes – “If the maximum turbidity levels were reached, the operators were warned by an alarm over their phones.”

Stripping of Dynamic Dredge Overflow Plumes was the unusual theme of Van Oord’s Erik van Eekelen who investigated the phenomenon – 3% to 5% removal of fines by dynamic plumes – using a tank.

“One experiment showed that a small vortex was created at the edge of the plume, which separated and formed a passive plume high in the water column – but it’s not a feature I’ve been able to replicate,” he said. Future research should look at irregularities in the overflow, ship movement, propeller suction and water density, he felt.

It was HR Wallingford’s Dr Caroline Fletcher who wrapped up the session with Measuring in the Grey: from Dredger to Sensitive Receiver.

“I want to question whether we’re hiding behind a lack of knowledge and whether we can do better than now. Are we actually recording and measuring the right information?” she asked, pointing out that while turbidity is an indicator of sediment in the water

column, “calibration is really important – turbidity will not give you the rate of sedimentation at a site.”

Given that different species of fauna and flora have different tolerances to sedimentation, she called for post-project monitoring – “I don’t think we’re learning enough from existing projects, more discussion is needed,” she said, asking those involved in ongoing sensitive projects to talk to her about them.

session ThreeChaired by DEME’s Bart Verboomen,

we moved to Case Studies with Martin Maloney’s cautionary tale of deepening an existing berth at the UK’s Port of Milford Haven first up.

“The project was to upgrade the berth to take ships up to 60,000dwt and was very simple – any engineer could do it in his sleep.” But the berth was in a heavily protected marine conservation area and the complications and wrangles that followed took 20 months and about £100,000 in man-hours before the dredging licence was granted.

Kenneth Piere, on the other hand, has environmentalists on his side in building

“To my great joy, more and more women are carrying out research in our industry,” said IADC secretary general Constantijn Dolmans, presenting the award to stephanie Janssen

Worth €1,000 plus publication in the IADC magazine Terra et Aqua, the award’s designed to encourage young people to carry out research and present their findings. And Stephanie’s paper on trust and partnering is “not only a contribution to theory, but to practice,” said Constantijn.

“It’s not a typical paper for a CEDA conference,” said Stephanie, “but partnering is a method of improving trust and projects.”

IADC Best Paper Award

Taking the prize

CEDA’s working to attract young professionals and conference chairman Freddy Aerts (centre, back row) was delighted with the turnout in Antwerp

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DPC Dredging Days 2008

Sponsored by DEME, it was another first for Dredging Days

A gloomy, rain-spattered evening couldn’t spoil delegates’ enjoyment as we headed off in groups to some of Antwerp’s most famous pubs, including the icon-filled 11 de Gebod (11th Commandment) underground drinking dens in the 16th century network of little alleys called Vlaeykensgang and finally the Groote Witte Arend (Great White Eagle) where dinner awaited.

Dredging Days 2009 will have to come up with something special to beat it!

Pub Crawling

Called the KRuibeKe-bazel-Rupelmonde pRoJect after the three villages, the 600ha area combines anti-flood measures with the restoration of the Scheldt’s estuarine environment – and was the site of Dredging Days’ technical visit

The Scheldt estuary basin area measures around 21,863km2 and the 1976 post-flood SIGMA plan gave it protection against a storm surge with an average return period of 70 years. Under the KBR Project, protection levels will climb to a return period of 350 years via enclosure by two different dyke constructions:1). A long river dyke – or ‘overflow dyke’

2). A high ring dyke – which protects the hinterland’s inhabitants.

At high tide and when a storm surge strikes, water’s allowed to flow over the river dyke, but the ring dyke ensures it remains in the controlled inundation area. By this method, any storm surge is capped, water upstream rises less and protection of local villages is improved.

At low tide and when any surge abates, the water’s allowed to flow back into the river via sluice gate outlet valves.

We arrived at Dredging International’s FCA-KBR office aboard a Jan De Nul-sponsored Flandria riverboat and, following a short

presentation, the visit included an outlet valve station as well as both the under-construction dykes. And a fascinating day was had by all.

Europe’s Biggest

gravity-based foundations for the Thornton Bank wind farm’s turbines.

It includes dredging 50m x 80m foundation pits and using concrete caissons ballasted with infill material – “Phase one involves six massive 5mW turbines whose rotors span 126m and Thornton Bank will have 60 of them,” Piere explained.

Piet Haerens followed up by looking at Thornton Bank’s morphology and the scour protection needed for the turbines – “the seabed morphology is relatively stable, but the installation of such structures leads to increased tidal velocity and thus scour,” he said.

His work is ongoing and defines stone sizes, layer thicknesses, the armour needed and more – “What we haven’t done yet is test the impact of breaking waves,” he said, wrapping up the session in the process.

The day concluded with CEDA’s AGM (see panel) followed by a guided tour and reception at Antwerp’s very beautiful 16th century town hall.

session FourDredging and European Ports

– Challenges and Opportunities was the theme of Prof Theo Notteboom’s keynote speech on Thursday 2 October – “We are slowly approaching the end of an era of large port infrastructure projects in Europe,” he said. “What role will the dredging industry have in future sustainable port development? What areas will grow and which will decline? Do upstream river ports have a future – and what about transhipment?” he asked.

His following detailed analysis looked at emerging gateways in the Black Sea and in Russia, the challenges posed by the economic downturn, capacity pressures and new environmental and security measures.

But he was optimistic: “I always try to reassure people that, even if there’s a recession, port traffic still increases.”

Remediation Techniques was session

a long-term project – the 500,000m3

means there’s work there for 10 years,” she commented, concluding the session.

session FiveThemed Dredging in Sensitive Areas,

the session began with Jeroen Gheysens’ study of the Brazilian Port of Sepetiba’s access channel, harbour basin and turning circle campaign – “We were dredging contaminated material, mostly zinc, in an area notable for fisheries and mangroves,” he said.

Apart from thorough monitoring, dredging equipment selection to minimise spillage proved a vital factor: “We used an environmental disk cutter and we also built a dyke to protect the mangroves, though the soil conditions were so poor it had to be maintained on a daily basis,” he concluded.

Salt marsh development in the eastern Scheldt was the subject of Bart Grasmeijer’s presentation and as he pointed out: “It’s about one-third its original size and still decreasing because of lack of sediment flow.”

four’s theme and with Karel Allaert in the chair, Joris Dockx got us under way with AMORAS, Antwerp’s new sediment treatment and dewatering concept (see DPC October 2008), including a film premiere of the plant.

“It has a smaller environmental footprint, should be in full operation by the second half of 2011 and is sustainable for the future,” he said.

The 30-month, €75M Taparura project in the Tunisian coastal city of Sfax (see DPC February 2007) shows what can be done to clean up and transform even the most contaminated sites, as Jan De Nul’s Bart Callaert described – “About 3M m3 of soil, plus an area in the sea, were heavily contaminated, mostly by heavy metals,” he told the audience.

Contaminated dredged material was also Sofie Herman’s theme, a study of the Port of Dunkirk’s concept of using settlement lagoons to deal with the 500,000m3 problem.

“It’s the first site in France to cope with contaminated sediment and is

WEDA exec director Larry Patella and wife Nancy at 11 de Gebod

Sluice gates in the river dyke

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“Quotes”

“A shipper told me that the annual cost of fuel for one vessel is what it would cost to build that vessel” – Prof Theo Notteboom

“After your breakfast I’m now going to serve you a dessert of cakes” – Joris Dockx on the sediment cakes formed by the AMORAS concept

“A well-trained and environmentally-aware crew is also important when you’re dredging sensitive areas” – Jeroen Gheysens

“Here’s the Netherlands – but I hope you all knew that!” – Bart Grasmeijer pointing to his project area on a map of Europe

“The trick in designing a dredger for reservoirs is to have a tool for everything, just like a Swiss Army knife” – Marcus Winkelman

“It’s not easy!” – Henk van Muijen on the complexities of building green dredgers

“The audience was asked ‘do you trust dredging contractors?’ I was the only one who raised his hand” – Constantijn Dolmans, IADC SG

The aim is to create new areas and four different methods of doing that had been studied, Bart said, with a plan to create about 12ha of salt marsh by building new channels coming out top. “It’s now up to Rijkswaterstaat [Dutch transport/water ministry] to decide when to start a pilot project,” he said.

That left Gijsbert van Holland to bring the session to a close with a highly topical view of the third Scheldt deepening project that will enable ships of up to 13.1m draught to reach the Port of Antwerp at all states of the tide. And around 7M m3 from the 14 dredging locations will create new ecological areas.

“We want to be sure they’ll be stable,” he noted, “as we don’t want the sediment flowing back into the channels where we’ll have to dredge it again!”

And on that note we all boarded one of the Flandria fleet of riverboats, sponsored by Jan De Nul, for the trip to DEME’s Kruibeke site office for a visit to Europe’s largest anti-flood project (see panel).

As for the evening, if you’ve never tasted Trappist beer with an alcoholic strength of up to 14%, Antwerp’s the place and the DEME-sponsored pub crawl was the trip to be on (see panel)!

LasT DayWith Robert van der Ketterij in

the chair, Friday’s session six on Technology and Equipment began with a surprisingly full audience given the night before! And Marcus Winkelman’s paper on dredging reservoirs and hydro-power dams explored the multiple uses of Damen’s DOP pump.

Challenges, as he pointed out, include remote sites, often high in mountain ranges, making maintenance a problem – “You also need a dredger small enough to pack into a container for shipment,” he said.

Choosing appropriate technology for dredger newbuilds was the theme of Jan De Nul’s Robby de Backer – and since his firm’s spending €1.8Bn building 25 vessels at present, he had plenty of scope.

“The dredger should have the least possible impact on the environment, as should the dredging operation, but how do you achieve this?” he asked. Efficiency in terms of kW per knot per ton and a holistic approach – “you have to look at all aspects” – were key, he said, along with modern design tools to ensure an optimised vessel.

IHC’s Henk van Muijen used the Brundtland Commission’s definition – Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs – as the basis of his study on developing green dredging equipment.

“For IHC that means long-term R&D, a focus on products, development

of a ‘people, planet, profit’ sustainability strategy, plus intensive co-operation with stakeholders,” he said. Today’s focus is on turbidity control, energy and emissions, plus sustainable equipment and production, he added, with examples of IHC’s work on these.

CEDA Environmental Commission chairman Politie Laborie then brought delegates up-to-date with the CEC’s work and events. “It’s very important to be proactive in legislation,” he commented, “and to that end we keep a close eye on EU legislation that will affect the dredging industry.”

The CEC’s also proactive in its guidance and work with partner organisations such as SEDNET, PIANC, ESPO and IADC – “We pass on knowledge that thinks of dredging as a tool for sustainable development and try to make life easier by advising governments,” he said, asking delegates to keep in touch and give feedback.

your viewThe conference concluded with a

panel discussion moderated by myself and beginning with short, positional statements on dredging and sustainable development from: Delft University's Prof Cees van Rhee, who gave the technical view Natuurpunt's Peter Symens, with the ecological view Cefas' Andrew Birchenough, gave the permit view Antwerp University's Prof Willy Winkelmans, economic view Jan De Nul's Bernard Malherbe, taking the place of the unavoidably absent Pascal Grégoire, gave the contractor’s view, and HR Wallingford's Caroline Fletcher stood in for colleague Nick Bray and gave the planning view.

A very lively discussion ensued over the next 75 minutes and many of the points made will be discussed by the CEDA board and the Environment Commission as to how they could influence future policy and activities.

FinaLLy...“I believe we’ve kept our finger on

the pulse over the past few days,” said Freddy Aerts in his closing remarks.

“Sustainable targets confront all of us and the end is not yet in sight – the ultimate goal is sustainable development in all our projects.”

Thanking the sponsors, his fellow chapter members and all who’d worked to make the conference a success, he concluded: “In short, as chairman of CEDA Belgium, I’m a happy man!”

Which just left new CEDA president Anders Jensen to thank the Belgian chapter – and invite delegates to Dredging Days 2009, 5-6 November in Rotterdam.You’ll find the full conference proceedings at www.dredging.org