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TERRA ETAQUA
International Association of Dredging Companies
Maritime Solutions for a Changing World
Number 123 | June 2011
FIXED LINK AT FEHMARNBELTuniting Europe’s transportation network
WHO REGULATES REMEDIATION?global survey on contaminated sediment
FIRST EXAMINE THE SEABEDwhy early sampling and testing matter
In the foreground a small elevated platform for geotechnical sampling through a shallow rock seabed and in the background
a landing craft for soils sampling in excess of 5 m water depth. Conducting a detailed geotechnical site investigation is crucial
to the execution of a successful project, therefore, dredging contractors and consultants need to be involved early on so as to
avoid expensive “surprises” once work starts (see page 24).
TERRA ETAQUA
Guidelines for Authors
Terra et Aqua is a quarterly publication of the International Association of Dredging Companies,
emphasising “maritime solutions for a changing world”. It covers the fields of civil, hydraulic
and mechanical engineering including the technical, economic and environmental aspects
of dredging. Developments in the state of the art of the industry and other topics from the
industry with actual news value will be highlighted.
• As Terra et Aqua is an English language journal, articles must be submitted in English.
• Contributions will be considered primarily from authors who represent the various disciplines
of the dredging industry or professions, which are associated with dredging.
• Students and young professionals are encouraged to submit articles based on their research.
• Articles should be approximately 10-12 A4s. Photographs, graphics and illustrations are
encouraged. Original photographs should be submitted, as these provide the best quality.
Digital photographs should be of the highest resolution.
• Articles should be original and should not have appeared in other magazines or publications.
An exception is made for the proceedings of conferences which have a limited reading public.
• In the case of articles that have previously appeared in conference proceedings, permission
to reprint in Terra et Aqua will be requested.
• Authors are requested to provide in the “Introduction” an insight into the drivers (the Why)
behind the dredging project.
• By submitting an article, authors grant IADC permission to publish said article in both the
printed and digital version of Terra et Aqua without limitations and remunerations.
• All articles will be reviewed by the Editorial Advisory Committee (EAC). Publication of an
article is subject to approval by the EAC and no article will be published without approval
of the EAC.
MEMbERShip liST iADC 2011Through their regional branches or through representatives, members of IADC operate directly at all locations worldwide
AfricAVan Oord Dredging and Marine Contractors, Luanda, Angola Boskalis International Egypt, Cairo, EgyptDredging and Reclamation Jan De Nul Ltd., Lagos, NigeriaDredging International Services Nigeria Ltd, Ikoyi Lagos, NigeriaNigerian Westminster Dredging and Marine Ltd., Lagos, NigeriaVan Oord Nigeria Ltd, Victoria Island, Nigeria
AsiABeijing Boskalis Dredging Technology Co. Ltd., Beijing, P.R. ChinaVan Oord (Shanghai) Dredging Co. Ltd, Shanghai, P.R. ChinaVan Oord Dredging and Marine Contractors bv Hong Kong Branch, P.R. ChinaBoskalis Dredging India Pvt Ltd., Mumbai, IndiaInternational Seaport Dredging Private Ltd., New Delhi, IndiaJan De Nul Dredging India Pvt. Ltd., IndiaVan Oord India Pte Ltd, Mumbai, IndiaP.T. Boskalis International Indonesia, Jakarta, IndonesiaPT Penkonindo LLC, Jakarta, IndonesiaPenta-Ocean Construction Co. Ltd., Tokyo, JapanToa Corporation, Tokyo, JapanHyundai Engineering & Construction Co. Ltd., Seoul, KoreaVan Oord Dredging and Marine Contractors bv Korea Branch, Busan, Republic of KoreaVan Oord (Malaysia) Sdn Bhd, Selangor, MalaysiaVan Oord Dredging and Marine Contractors bv Philippines Branch, Manilla, PhilippinesBoskalis International Pte Ltd., SingaporeDredging International Asia Pacific (Pte) Ltd., SingaporeJan De Nul Singapore Pte. Ltd., SingaporeVan Oord Dredging and Marine Contractors bv Singapore Branch, SingaporeZinkcon Marine Singapore Pte. Ltd., SingaporeVan Oord Thai Ltd, Bangkok, Thailand
AusTrAliA + NEW ZEAlANDBoskalis Australia Pty, Ltd., Sydney, AustraliaDredeco Pty. Ltd., Brisbane, QLD, AustraliaJan De Nul Australia LtdVan Oord Australia Pty Ltd., Brisbane, QLD, AustraliaWA Shell Sands Pty Ltd, Perth, AustraliaNZ Dredging & General Works Ltd, Maunganui, New Zealand
EuropEBaggerwerken Decloedt & Zoon NV, Oostende, BelgiumDEME Building Materials NV (DBM), Zwijndrecht, BelgiumDredging International N.V., Zwijndrecht, BelgiumJan De Nul n.v., Hofstade/Aalst, BelgiumBoskalis Westminster Dredging & Contracting Ltd., CyprusBoskalis Westminster Middle East Ltd., Limassol, CyprusVan Oord Middle East Ltd, Nicosia, CyprusRohde Nielsen, Copenhagen, DenmarkTerramare Eesti OU, Tallinn, EstoniaTerramare Oy, Helsinki, FinlandAtlantique Dragage Sarl, St. Germain en Laye, FranceSociété de Dragage International ‘SDI’ SA, Lambersart, FranceSodraco International S.A.S., Lille, France Sodranord SARL, Le Blanc-Mesnil Cédex, FranceBrewaba Wasserbaugesellschaft Bremen mbH, Bremen, GermanyHeinrich Hirdes G.m.b.H., Hamburg, GermanyNordsee Nassbagger-und Tiefbau GmbH, Bremen, GermanyVan Oord Gibraltar Ltd, GibraltarIrish Dredging Company, Cork, IrelandVan Oord Ireland Ltd, Dublin, IrelandBoskalis Italia, Rome, Italy
Dravo SA, Italia, Amelia (TR), ItalySocieta Italiana Dragaggi SpA ‘SIDRA’, Rome, ItalyBaltic Marine Contractors SIA, Riga, LatviaDredging and Maritime Management s.a., Steinfort, LuxembourgDredging International (Luxembourg) SA, Luxembourg, LuxembourgTOA (LUX) S.A., Luxembourg, LuxembourgAannemingsbedrijf L. Paans & Zonen, Gorinchem, NetherlandsBaggermaatschappij Boskalis B.V., Papendrecht, NetherlandsBoskalis B.V., Rotterdam, NetherlandsBoskalis International B.V., Papendrecht, NetherlandsBoskalis Offshore bv, Papendrecht, NetherlandsDredging and Contracting Rotterdam b.v., Bergen op Zoom, NetherlandsMijnster zand- en grinthandel bv, Gorinchem, NetherlandsTideway B.V., Breda, NetherlandsVan Oord ACZ Marine Contractors bv, Rotterdam, NetherlandsVan Oord Nederland bv, Gorinchem, NetherlandsVan Oord nv, Rotterdam, NetherlandsVan Oord Offshore bv, Gorinchem, NetherlandsDragapor Dragagens de Portugal S.A., Alcochete, PortugalDravo SA, Lisbon, PortugalBallast Ham Dredging, St. Petersburg, RussiaDravo SA, Madrid, SpainFlota Proyectos Singulares S.A., Madrid, SpainSociedade Española de Dragados S.A., Madrid, SpainBoskalis Sweden AB, Gothenburg, SwedenDredging International (UK) Ltd., Weybridge, UKJan De Nul (UK) Ltd., Ascot, UKRock Fall Company Ltd, Aberdeen, UKVan Oord UK Ltd., Newbury, UKWestminster Dredging Co. Ltd., Fareham, UK
MiDDlE EAsTBoskalis Westminster Middle East Ltd., Manama, BahrainBoskalis Westminster (Oman) LLC, Muscat, OmanBoskalis Westminster Middle East, Doha, QatarMiddle East Dredging Company (MEDCO), Doha, QatarBoskalis Westminster Al Rushaid Co. Ltd., Al Khobar, Saudi ArabiaBoskalis Westminster M.E. Ltd., Abu Dhabi, U.A.E.Gulf Cobla (Limited Liability Company), Dubai, U.A.E.Jan De Nul Dredging Ltd. (Dubai Branch), Dubai, U.A.E.National Marine Dredging Company, Abu Dhabi, U.A.E.Van Oord Gulf FZE, Dubai, U.A.E.
ThE AMEricAsBoskalis International bv Sucural Argentina, Buenos Aires, ArgentinaCompañía Sud Americana de Dragados S.A, Buenos Aires, ArgentinaJan De Nul do Brasil Dragagem LtdaVan Oord ACZ Marine Contractors bv Argentina Branch, Buenos Aires, ArgentinaVan Oord Dragagens do Brasil Ltda, Rio de Janeiro, BrazilVan Oord Curaçao nv, Willemstad, CuraçaoDragamex SA de CV, Coatzacoalcos, MexicoDredging International Mexico SA de CV, Veracruz, MexicoMexicana de Dragados S.A. de C.V., Mexico City, MexicoCoastal and Inland Marine Services Inc., Bethania, PanamaDredging International de Panama SA, Panama Westminster Dredging Overseas, TrinidadStuyvesant Dredging Company, Louisiana, U.S.A.Boskalis International Uruguay S.A., Montevideo, UruguayDravensa C.A., Caracas, VenezuelaDredging International NV - Sucursal Venezuela, Caracas, Venezuela
Terra et Aqua is published quarterly by the IADC, The International Association
of Dredging Companies. The journal is available on request to individuals or
organisations with a professional interest in dredging and maritime infrastructure
projects including the development of ports and waterways, coastal protection,
land reclamation, offshore works, environmental remediation and habitat restoration.
The name Terra et Aqua is a registered trademark.
for a free subscription register at www.terra-et-aqua.com
All rights reserved. Electronic storage, reprinting or
abstracting of the contents is allowed for non-commercial
purposes with permission of the publisher.
ISSN 0376-6411
Typesetting and printing by Opmeer Drukkerij bv,
The Hague, The Netherlands.
Contents 1
EDITORIAL 2
THE FEHMARNBELT TUNNEL: 3REGIONAL DEVELOPMENT PERSPECTIVESPETER LUNDHUS AND CHRISTIAN WICHMANN MATTHEISSEN
After almost 2 years of extensive study of conceptual designs, the plans for
the “missing” transportation link across the Fehmarnbelt from Denmark to
Germany are ready to proceed. The present-day ferry takes 45 minutes plus
waiting time. The link will take 7 to 10 minutes.
REMEDIATION OF CONTAMINTED SEDIMENT: A WORLDWIDE 14STATUS SURVEY OF REGULATION AND TECHNOLOGYPHILIP A. SPADARO
Remediation projects are becoming more frequent: Here’s a snapshot of
the current state of the industry, including which countries at present have
a regulatory framework and/or technical framework in place (and which
do not), and what technologies are actively being used.
THE IMPORTANCE OF BED MATERIAL CHARACTERISATION IN PLANNING 24DREDGING PROJECTSMICHAEL P. COSTARAS, R.N. BRAY, RICHARD P. LEWIS AND MARK W.E. LEE
Insufficient, inaccurate and irrelevant data about bed material can lead to
unwanted surprises, whereas early advice from contractors and specialist
consultants and adequate testing and sampling early on can offer cost-savings
down the road.
BOOKS/PERIODICALS REVIEWED 31A new book from IOC/UNESCO Understanding Sea-Level Rise and Variabilitytackles this difficult subject; and a new Facts About Dredging Around Coral Reefs is available.
SEMINARS/CONFERENCES/EVENTS 34“Forum on Early Contractor Involvement” is coming up in late June. CEDA Dredging
Days, CHIDA’s conference, PIANC COPEDEC and more follow.
contents
eDItoRIALAmongst the multiple activities of the umbrella organisations that represent the worldwide
dredging community – such as International Association of Dredging Companies (IADC),
the World Dredging Association (WODA) comprising CEDA, WEDA and EADA – are several
publications, including Terra et Aqua, and myriad congresses and conferences that take place
throughout any given year around the world, on a diversity of subjects that impact dredging
and maritime construction projects.
Attending these conferences, and perusing through their proceedings, often known as “grey
literature”, is one significant source of Terra articles which turn grey into black ink – or
downloadable files. Adjoining this are presentations of awards from IADC to young authors at
selected conferences – coming up soon at the 2011 WEDA and CEDA meetings – to encourage
young people to continue working in and doing research for the dredging industry.
Such research is the lifeline of any modern industry and encouraging the flow of innovative,
forward-looking technical, environmental and managerial information has become a focus of
IADC over the years.
But attending conferences is only half the story. In a
cooperative effort, CEDA and IADC, have often joined forces
to launch their own events. This year a new conference
entitled, “Forum on Early Contractor Involvement”, ECI for
short, has gone from the drawing board to reality. Schedule to
take place June 23-24 at the Hilton London Docklands (for
registration information see page 35), this forum represents
the recognition by a diverse group of professionals that the
sooner contractors become involved with a project, the better
it is for everyone – the project owner, the public and other
stakeholders. The theme, “Partnering Creates Possibilities”,
says it clearly – but when is ECI an appropriate solution?
And how do we implement it?
By inviting a broad range of speakers representing clients, consultants, lawyers and engineers,
the organisers have created an unusual formula. These presenters will lay the groundwork for
interactive, facilitated workshops which will follow: Audience participation is a must. In this way,
all attendees – financiers, insurers, engineers, government agents, contractors, consultants and
project owners will get a chance to share their experiences and tackle the questions about the
shared risks and responsibilities implicit in ECI. The overriding question is: How can ECI help
create a future where one can advance “maritime solutions for a changing world”, as our
Terra motto states, in the best, most cost-effective way.
In this issue of Terra et Aqua you will find articles that connect to this theme: one on the
proposed Fehmarnbelt link which will connect Denmark and Germany, where environmental,
technical and other studies are still being prepared; a global status survey of the contaminated
sediment policies, so crucial to the execution of dredging works; and one in which the necessity
for the characterisation of bed materials early on in a project is emphasised. As reflected in
these articles, “early contractor involvement” is more than a conference theme. It is a path to
successfully executing mega projects where complexities and environmental considerations
continue to challenge our best and brightest minds.
Koos van OordPresident, IADC
Koos van OordIADC, President
2 Terra et Aqua | Number 123 | June 2011
Register now
FORUM on
23 - 24 June 2011Hilton London Docklands, UK
• project owners• financiers • contractors • insurers• construction lawyers • regulators • government agencies and NGOs • advisors to decision makers in maritime infrastructure construction
An interactive forum and networking event.
“A paradigm shift is taking place in procurement. And we need to educate the client and contractors”.
Dean Kashiwagi
Organised by:
Partnering Creates Possibilities
Organised by: Supported by:
Early Contractor Involvement
www.dcm-conference.org
FOR WHOM:
WHAT:
WHEN and WHERE:
ABSTRACT
The Fehmarnbelt Link between Denmark and
Germany, for which in September 2008 a
bilateral government treaty was signed, is the
last of the three links uniting transportation
networks in Northern Europe. The three links
(the Great Belt and the Øresund Link being
the other two) are impressive mega structures
(bridges/ tunnels) spanning international
waterways. They concentrate traffic flows
and create strong transport corridors and
are the basis of new regional development
regimes.
In early 2011, following almost two years of
extensive work on different conceptual
designs for the fixed link it was decided that
an immersed tunnel should form the basis for
the continuous planning of the project,
including the environmental impact studies.
Completion of the link is scheduled for 2020.
INTRODUCTION
In the 1980s The European Round Table of
Industrialists identified 14 missing links in the
transportation network of the continent.
Three of them were found around the Danish
island of Zealand (see Figures 1a and 1b).
One link was within Denmark; the other two
were between nations. One link connects
heavy economic centres, one joins more thinly
populated regions and the last one links
peripheral areas. Two of them (the Great Belt
Link – linking the Danish islands of Zealand
and Funen and the Øresund Link between
Denmark and Sweden) have been constructed
and are fully operational. The third – the
Fehmarnbelt Link between Denmark and
Germany – was decided in 2008 on a bilateral
government level. The three links are
impressive mega structures (bridges/ tunnels)
spanning international waterways.
Their lengths are around 20 km (12 miles)
each. They concentrate traffic flows and
create strong transport corridors. They are the
basis of new regional development regimes.
“Ferries connect systems, fixed links unite
systems”. The concept of missing links has
been adapted by the European Union in
different large-scale strategies.
Above: The present situation showing the ferry with
vehicles coming from Puttgarden (Germany)
disembarking at Rødby (Denmark). The fixed
Fehmarnbelt link will not only take over the transport
services now carried out by the ferries between Rødby
and Puttgarden. It will forge new relations between the
communities on both sides of the link.
tHe FeHMARnBeLt tUnneL: ReGIonAL DeVeLoPMent PeRsPectIVes
PeteR LUnDHUs AnD cHRIstIAn WIcHMAnn MAttHIessen
Following these new strategies, the Trans-
European Transport Network was adopted
and implemented nationally in different ways.
Some countries have been focussing on high-
speed railway infrastructures, others have
improved airports and seaways, and in
Denmark the three fixed links totalling a
€13 billion investment have been given high
priority in the national transport action plans.
The revision of the guidelines and the new
EU initiatives regarding “Green Corridors”
intends to substantially affect funding
programmes of the TEN-T towards fostering
sustainable cross-border transport
infrastructure linking up to policies of
regional development, innovation and growth.
The third fixed link, the Fehmarnbelt Link
forms a giant step in the creation of a new
North-European corridor.
The first stage of the Northern European
integration project was completed with the
opening in 1997/1998 of the fixed link across
Denmark’s Storebælt (Great Belt) (Figure 2).
This represented a giant leap into the future
in terms of logistics and physical interaction
between East and West Denmark. Although
networks across Storebælt already existed,
the new link largely increased the potential
for co- operation between the various parts
of Denmark.
The Fehmarnbelt Tunnel : Regional Development Perspectives 3
4 Terra et Aqua | Number 123 | June 2011
The second stage, the Øresund Fixed Link was
ready in 2000 (Figure 3). Despite the fact that
the Øresund Region’s major cities appeared
to provide good pre-bridge opportunities for
integration, only some fairly weak networks
had been established between Scania in
Sweden and Zealand in Denmark. The opening
of the Øresund Bridge/tunnel, therefore,
substantially improved potential networking
across the strait and, following a somewhat
sluggish start, due to lack of updated
administrative rules, such links ever since have
been steadily growing in a learning process.
With the decision by Germany and Denmark
to enter the third stage and build a fixed
Fehmarnbelt link, the two nations not only
embarked on a large-scale project to improve
the infrastructure of Northern Europe and
reduce travel times, but also to stimulate
economic, cultural and social development in
the areas, regions and countries around the
link. With the fixed Fehmarnbelt link, one of
the world’s mega projects in terms of logistics
will be completed. “The missing Scandinavian
link” will no longer be “missing”.
The fixed Fehmarnbelt link will result in
considerably changes. Although differences
between the German and Scandinavian
languages and the fact that the near areas are
sparsely populated will constitute barriers to
the area’s development. Nevertheless, the
potential gains are significant. And one thing
is certain: As new infrastructure projects of
this size have always resulted in major
changes, the link will create growth and
development.
The fixed Fehmarnbelt link will not only take
over the transport services previously carried
out by the ferries between Rødby and
Puttgarden. No less important is the fact that
new relations between the communities on
both sides of the link will be forged –
between southern Zealand, Lolland and
Falster in Denmark and eastern Holstein in
Germany as well as, further afield, between
Copenhagen/the Øresund city and Hamburg.
As a result, new trading opportunities, new
forms of tourism, new jobs and new housing
opportunities will arise. In turn, this will open
up new regional development perspectives
for the entire Fehmarnbelt region. Already a
range of contacts and partnerships are being
formed between Denmark, Germany and
Sweden for the purpose of exploiting the
opportunities created by the fixed
Fehmarnbelt link.
The treaty on the construction of a fixed
Fehmarnbelt link was signed by the Danish
and German governments on 3 September
2008. The decision engendered strong focus
on the development perspectives following
the fixed link’s completion in 2020.
PLAnnInG tHe FeHMARnBeLt tUnneL: stAte oF tHe ARtIn early 2011, following almost two year’s
extensive work on different conceptual
designs for the fixed link it was decided that
an immersed tunnel should form the basis for
the continuous planning of the project
including the environmental impact studies.
However, alternative technical solutions – for
example a cable-stayed bridge – are still being
considered and benchmarked. The decision on
S W E D E N
SCANIA
Malmö
ZEALAND
LOLLAND-FALSTER
Copenhagen
SCHLESWIG-HOLSTEIN
MECKLENBURG-VORPOMMERN
FUNEN
JUTLAND
Hamburg
Kiel
Lübeck
Rostock
D E N M A R K
P O L A N D
G E R M A N Y
0 25 50 75 100 Km
D E N M A R K
P O L A N D
G E R M A N Y
S W E D E N
SCANIA
SCHLESWIG-HOLSTEIN
MECKLENBURG-VORPOMMERN
ZEALAND
LOLLAND-FALSTER
FUNEN
JUTLANDCopenhagen
Hamburg
Malmö
Kiel
Lübeck
Rostock
Great B
elt
F ehmarnbelt
Øre
sund
0 25 50 75 100 Km
Figure 1a. Pre-fixed links:
Southern Scandinavia plus
parts of Northern Europe.
Distance between the
Zealand archipelago and
the rest of the region as
time: 1 hour equals 80 km.
The three ovals indicate the
location of the ferry lines
and the “Missing
Scandinavian Links” as
stated in the late 1980s.
Western oval (left): The
Great Belt. Eastern oval
(right): Øresund. Southern
oval: Fehmarnbelt. Larger
oval at Øresund indicates
several ferry cross
Figure 1b. Post-fixed links:
Southern Scandinavia plus
parts of Northern Europe.
Solid line: Existing
connections and roads.
Broken line: Fehmarnbelt
link to be constructed.
Distance in kilometres.
which solution is finally to be built will be
made pursuant to a specially enacted
construction act in Denmark and subject to
approval by the German authorities. The final
approval is expected in 2013.
The recommendation of the immersed tunnel
is based on a preliminary, comprehensive
assessment of, not least, environmental and
safety issues including navigational safety but
also technical, traffic, time and financial issues.
The state-of-the-art tunnel under the
Fehmarnbelt is set to be one of the safest in
the world (Figure 4) . With a length of about
18 km it will also be the world’s longest
combined road-rail tunnel to date. The tunnel
will be five times the length of the Øresund
tunnel (approx. 4 km) between Copenhagen
and Malmö and three times the length of the
Trans-Bay Tube Bart Tunnel in San Francisco,
which is currently the world’s longest immersed
tunnel. The total length of the Fehmarnbelt
tunnel will be about 18 km from tunnel mouth
to tunnel mouth. At a speed of 110 km per
hour, this will offer motorists a journey time of
approximately 10 minutes through the tunnel.
For train passengers, the journey will take seven
minutes from coast to coast.
Technical challengesAn immersed tunnel will present considerable
technical challenges during the construction
phase, as a result of the intensive shipping
traffic in the Fehmarnbelt. However, unlike a
bridge, an immersed tunnel will not entail as
many technical operations which push the
limits of what has been done before.
Essentially, the procedure will be the same as
it was for construction of the Øresund Fixed
Link’s immersed tunnel under the Drogden
Channel, only many more times over and at
greater depth, i.e., up to 30-40 metres in the
Fehmarnbelt compared to approximately
25 metres in the Øresund.
A cable-stayed bridge across the Fehmarnbelt,
with two free spans of 724 m each, would be
the largest spans ever constructed for
combined road and rail traffic. Compounded
by the high shipping traffic in the area, this
would pose significant risks in the construction
phase in terms of cost overruns, delays and
industrial accidents. One of the key parameters
for the choice of technical solution is the
environmental impact of the projects. Both a
cable-stayed bridge and an immersed tunnel
would impact the marine environment in the
Fehmarnbelt. The preliminary conclusion is that
a bridge would have slightly more significant
permanent environmental impacts than an
immersed tunnel. A number of the
environmental impacts of a fixed link would be
on Natura 2000 sites. In such instances, EU
legislation prescribes that the least intrusive
alternative must be selected.
In the interests of navigation safety, a tunnel
clearly poses fewer risks than a bridge.
The Fehmarnbelt is a heavily trafficked stretch
of water with 47,000 vessel transits per
annum (2006), including many tank vessels.
In the coming years, shipping traffic in the
Fehmarnbelt is expected to increase
substantially to approximately 90,000 vessel
transits in 2030. However, risk analyses for a
bridge show that, from a vessel perspective,
navigation safety would be improved in
relation to a situation with no bridge and
continued ferry crossings. This would require
a cable-stayed bridge with two navigational
spans of at least 724 m each, and the
implementation of permanent, radar-based
vessel monitoring in the form of a Vessel
Traffic Service (VTS) system covering a range
from the south end of the Great Belt to the
Cadet Channel.
Financial factorsIn financial terms, there is at the outset very
little difference between the two projects.
The construction estimate (2008 price level)
for an immersed tunnel is € 5.1 billion and
for a cable-stayed bridge, € 5.2 billion.
Assessment of the overall cost of each of the
two projects must also take into account the
construction time and the cost of operation
and maintenance. The construction time for
the tunnel is estimated at 6.5 years, and for
the bridge, 6 years. The cost of operation
and maintenance is slightly higher for a tunnel
than for a bridge.
All told, the payback time for the two projects
would be essentially the same: approximately
30 years for the coast-to-coast project.
This means that, from an overall financial
perspective, there is no difference between
bridge and tunnel.
PETER LUNDHUS
received his MSc in Civil Engineering,
Technical University of Denmark and Public
Negotiation, Harvard. He worked
internationally for Christiani & Nielsen
covering all aspects of design, bidding and
construction of civil engineering works, e.g.,
tunnels, bridges and harbour works in
Europe, Asia and Africa from 1973-1988.
He then joined the Great Belt Link A/S in
Denmark (1988-1992), in 1990 becoming
Project Director for the 8-km-long bored
twin railway tunnel, a significant part of the
18-km-long, combined tunnel and bridge
toll-funded link for road and rail between
the eastern and western parts of Denmark.
From 1992-2000 he was Technical Director
in Øresundsbrokonsortiet, a joint Danish-
Swedish company tasked with the
construction of the 16-km-long toll-funded
tunnel and bridge link crossing the Øresund
between Denmark and Sweden.
Since 2001 he is Technical Director for
Femern A/S, a state owned company which
is tasked with the planning of a fixed link
between Denmark and Germany across the
Fehmarnbelt.
CHRISTIAN WICHMANN
MATTHIESSEN
earned his MSc, PhD and Dr. Scient at
the University of Copenhagen, Denmark.
He has been Professor, Urban Geography
since 1988. He was head of the
Department 1986-1990 and 1996-1999
and President of the. National Committee
for Geography 1998 and on the
International Union of Geography, Urban
Geography Commission Board of Directors
in 2000 and President 2008-2012. He has
been on the Board of Directors of the Royal
Danish Society of Geography, the European
Institute of Comparative Urban Research,
the Center for Regional and Tourism
Research, and part of the Danish
Government’s Commission on
Infrastructure 2006-2008. His research has
covered a wide range of fields such as
Urban System Structure and Function,
Urban Growth, Large City (Re)-vitalization,
Implications of Infrastructural Investments,
Metropolitan Competition, Regional
Development, Tourism and Triple Helix –
co-operation between universities,
corporate world, regional government.
The Fehmarnbelt Tunnel : Regional Development Perspectives 5
Safety in the tunnelThorough safety analyses have been
conducted and the proposed tunnel more
than meets all relevant safety standards
– including the EU’s tunnel safety directive –
because of the end-to-end emergency lane,
amongst other features. The requirements for
road tunnels have increased a great deal over
the last decade. The design of the
forthcoming Fehmarnbelt tunnel takes all the
new requirements into account.
For motorists, the immersed tunnel will be at
least as safe as a standard motorway.
All traffic will run in separate one-direction
tunnel tubes so there is no oncoming traffic.
To minimise the risk of accidents, a
computerised traffic control system will be
installed and there will be a 24-hour manned
control centre. Moreover, traffic information
will be available on FM radio and signage for
motorists and varied architectural lighting will
be installed in the tunnel so drivers can
maintain concentration for the full 10 minute
journey.
As is the case with flying, studies show that
some few users may feel discomfort when
entering and driving in tunnels. For a very few
users, the discomfort is so intense that it will
make them choose an alternative route.
Correspondingly, a similar number of users
Figure 2. The Great Belt Bridge connecting the Danish islands of Funen and Zealand represented a giant leap into the
future in terms of logistics and physical interaction between eastern and western Denmark.
Figure 3. The Øresund Bridge between Denmark and Sweden. The opening of this bridge/tunnel link has substantially
improved networking across the strait.
LandscapingThe tunnel will be almost invisible in the
landscape, with the exception of the portal
buildings and landfills. The tunnel will not
impact the marine environment once it has
been built. The preliminary environmental
investigations show that an immersed tunnel
has the least permanent environmental effects
and thus also requires fewer measures to
minimise environmental impacts.
The proposal is for the tunnel to be
constructed almost in a straight line from
coast-to-coast. On the German side, motorists
will drive over a small hill and then down-
wards into a green valley before arriving at
the mouth of the tunnel (Figure 8). After
a gradual transition to artificial lighting, they
will continue into a tunnel with light-coloured
walls and architectural decoration.
The approach on the Danish side of Lolland
will be characterised by a designed landscape
and will be marked by a portal containing the
control and monitoring centre. In this way,
the portal building on the Danish side is
envisaged as a landmark for travellers en
route to Germany (Figure 9).
tHe GeoGRAPHY oF tHe FeHMARnBeLt ReGIonThe Fehmarnbelt region comprises the Zealand
archipelago, Bornholm, Schleswig -Holstein,
Hamburg and Scania. Parts of Mecklenburg-
Vorpommern and, when discussing major
cities, Rostock are at relevant occasions
included in the Fehmarnbelt region. The region
comprises 9.3 million people with 1.2 million
in the Swedish part, 2.5 million in the Danish
part and 5.6 million in the German part.
In 1997-1998 the Zealand archipelago was
joined to mainland Europe by the opening
of the Great Belt tunnel and bridge whilst
the fixed link between Zealand and the
Scandinavian peninsula, the Øresund Bridge,
was commissioned in 2000. The two mega
bridges/tunnels have significantly changed the
geographical reality for Southern Scandinavia.
Looking at the diagram in Figure 10, what is
striking are the traffic jumps following the
opening of the fixed links. The traffic jump
was significant after the opening of Great Belt
Bridge and developments subsequently
entailed a new, lasting, growth regime.
The reason was that a series of networks
were already in place and were waiting to
be employed in new and more value creating
ways. Family ties were national, companies
had Denmark as their market and the public
sector, institutions and organisations were
organised on a nationwide basis. What was
needed was simply to change the logistics
and localisation patterns.
There was also a traffic jump following the
opening of the Øresund Bridge, but this took
longer because there were no existing, well-
The Fehmarnbelt Tunnel : Regional Development Perspectives 7
experience anxiety driving across long or high
bridges. When driving in tunnels the anxiety
can be relieved with creative and strong
lighting, decoration, clear information with
frequent signage and a welcoming and
reassuringly safe design for the tunnel portals
(Figure 7).
With the dramatic decrease in hazardous
emissions from cars and trucks in the last ten
years, the “piston effect” – longitudinal
ventilation – of the vehicle traffic will be
sufficient to comply with the requirements
for air quality in the tunnel during normal
operation. In the event of irregular operation,
a fire or discharge of toxic fumes, the
ventilation system will ensure that motorists
can get safely out of the tunnel and that
rescue and emergency teams can work safely.
In addition, a sprinkler system will be installed
in the tunnel, which will limit the extent of
any fire and smoke.
There will be a central gallery between the
road tunnel tubes to which the motorists can
go in the event of an accident. Approximately
every 100 metres there will be cross-
connections between the tunnels, which
means that there will be no more than around
50 metres to the nearest emergency exit.
The over-pressure ventilation in the central
gallery will ensure that there is fresh air and
no smoke in the gallery in the event
of a fire.
Figure 4. The approach ramp and portal structure on the Danish side of a Fehmarnbelt tunnel with the control and monitoring facilities seen from the north towards the south.
8 Terra et Aqua | Number 123 | June 2011
localisation factors for infrastructure, transport
and logistics. Compared to the domestic
regional traffic, traffic across Fehmarnbelt is
weak and cross-border infrastructure consists
of ferry services. Although there are also
ferries across Øresund, the Øresund Bridge
constitutes the significant link between
Zealand and Scania.
Basically, there are three different perspectives
for regional development. The first comprises
the interaction between the major heavy
centres, i.e. between Copenhagen–Malmö-
Lund (the Øresund City) on the one side and
especially Hamburg, but also Kiel, Lübeck and
Rostock on the other. Within this perspective,
short term, this will probably be less dramatic
than it was following the two other mega
projects (the Great Belt and Øresund links)
because there are no well established
networks across the Fehmarnbelt or heavy
centres near the future fixed link. By contrast,
predictions suggest that the project will create
a new lasting growth regime based on its
considerable value creating potential,
particularly brought about by the establish-
ment of new networks and because a new
border regional framework calls for action.
ReGIonAL AnALYsIs PeRsPectIVesIn the Fehmarnbelt region, the national sea
borders act both as system separators and as
developed networks to build upon. Rather,
developments following the Øresund Bridge
can be described as something entirely new
with a learning process in which all
localisation decisions were taken in light of
the fixed link as a reality, where logistics
acquired new development opportunities and
where new economies of scale were added to
the agenda with their starting point in an
overall Danish/Swedish metropolitan region.
The question now is how the transport picture
at Fehmarnbelt will change post fixed link.
There is no doubt that changes will occur and
that the fixed Fehmarnbelt link will result in a
traffic jump and new growth potential. In the
Figure 5. The Fehmarnbelt tunnel will be constructed from 79 standard elements each 217 m long and 10 shorter special elements to be located every 1.8 km.
Figure 6. The special elements will ensure that ongoing operations and maintenance can be carried out without disrupting traffic. Beneath the road lanes and the rail track, there
will be access to all technical rooms. Personnel, therefore, do not have to cross the traffic.
The Fehmarnbelt Tunnel : Regional Development Perspectives 9
have a substantial and statistically significant
positive impact on house prices. These
estimates do not take other future dynamic
changes into account, such as new property
developments or new commuting trends. An
8 per cent increase in the price of the average
house on the German side corresponds to an
absolute increase in 2009 prices of €16,000.
The estimates for the Danish side are some-
what more uncertain, but can be expected to
fall within the same range. Using data from
housing markets in other areas with high-
speed train links shows an overall increase in
residential property values of €1.6 billion on
the German side of the Fehmarnbelt.
The total increase for the local housing
markets on the Danish side would amount
to at least €1.4 billion. The total minimum
increase – assuming high-speed rail service
links – thus amounts to €3 billion in 2009
prices (providing the economic structure in
Denmark and Germany remains unchanged).
One can assume, therefore, that the improved
infrastructure in the areas near the fixed
Fehmarnbelt link will result in relocations from
Greater Copenhagen to the Danish areas near
the link and similarly, relocations from
Hamburg to the North German areas near
the link.
Differences in property prices will not, to the
same extent as has been seen around Øresund,
promote border commuting although the new
increasingly set to become the backbone
of Europe’s mass transport system. These
opportunities are too good to miss.
Those areas (Lolland-Falster, the Northeastern
part of Schleswig- Holstein), which border the
future fixed link, can expect job losses when
the link opens and the ferry services cease
operating. This is unavoidable, but it could
mean that these areas mobilise and demand
new localisation of government assets.
This was, for instance, the case with West
Zealand’s success in connection with the
construction of the Great Belt Bridge where
the Danish government came under pressure
to move the Copenhagen naval station to
Korsør and did so. However, there are also
gains to be had. The property market will
respond to more efficient transport
connections and to the fact that access to
major cities in the neighbouring country will
be much faster and more convenient.
The areas that border the fixed link will
become “real” border regions with
neighbours in another country within daily
reach and commuting areas to the centres
expanded.
Property price increaseAs part of the project of reference
(Matthiessen, ed. 2011), the impact of
accessibility on house prices is estimated.
These estimates confirm that a fixed link will
there are almost exclusively potential gains.
The second perspective comprises those parts
of the region that are close to the
Fehmarnbelt. Here it is not only about
potential winners, but also realising that once
the fixed link is completed, jobs linked to the
ferries and crossings will disappear and that at
the same time construction work will cease.
The third perspective encompasses the other
ferry towns, which will experience new tough
competition (compare Figures 11 and 12).
The major cities will experience new growth
potential. First and foremost, this will apply to
the Øresund City and Hamburg and secondly
to Kiel, Lübeck and Rostock which, however,
will see some negative development potential
in that ferry services in these towns will be
exposed to strong competition. The major
cities will also see a strengthening of their
crossing point function, which will make them
more attractive as localisation targets for a
wide range of activities. They themselves will
be occupied by strengthening the interaction
within areas that create new value by
exploiting both the complementary
opportunities and supplementing each other’s
activities. They will be better positioned within
the international metropolitan competition.
Moreover, the construction of the fixed
Fehmarnbelt link will provide great
opportunities for linking the Øresund City
and the heavy Scandinavian centres to the
network of high-speed trains that are
Figure 7. Three colored zones
and illustrations on the walls
of the road tunnel will help to
give motorists a varied journey
during their 10 minute drive
through the Fehmarnbelt
tunnel.
10 Terra et Aqua | Number 123 | June 2011
and prosperity and future prospects. Without
these cities, the region would not have an
international format.
These two cities, however, are not alone as
high level centres. Berlin, Frankfurt and
Stockholm also play significant roles in the
region, Berlin as Germany’s capital and a so
far failed bid to establish itself in the elite of
world cities. Frankfurt and Stockholm are in
a class to which Berlin aspires. Frankfurt has
a dominating role within Europe’s financial
world, which in other major nations is often
located in the capital. In addition, the city is
one of the world’s large intercontinental
airport centres. Stockholm occupies a
significant role in terms of large international
business groups as well as being Sweden’s
capital, but is nevertheless more isolated in
respect of global integration than the other
heavy centres.
Interaction is always an expression of added
value. As a result, it makes sense to examine
new opportunities and what these analyses
can be used for. The view is that if stronger
links, first between Copenhagen and
Hamburg and second with Stockholm and
Berlin could be created, a new North
European axis could result, i.e., a network of
mutually strongly linked cities with uniform
partnership relations with the rest of the
world. Such an axis could claim a position at
a higher level within the continent’s urban
hierarchy and thus contribute to development,
growth and wealth.
motorways and railroads (inclusive high speed
train lines), whilst the Øresund city plays the
same role for Scandinavia (excluding high
speed train lines).
International air transport indicates the
potential accessibility for the flow of people
and the handling of high value cargo.
Copenhagen is an important centre with flight
connections to cities on four continents and
a strong European network whilst Hamburg
is served by relatively few international flights
and has a modest European network.
On non-material accessibility the Internet
backbone network Copenhagen performs well
and Hamburg is also a central hub, but not as
important as Copenhagen.
The Fehmarnbelt link and the Øresund Bridge
will bring Schleswig-Holstein and Hamburg
closer to the Øresund regional market. Perhaps
even more important, they will create a direct
portal for the entire Scandinavian market of
almost 20 million inhabitants (Sweden,
Denmark and Norway). The same scenario is
presented by Scania and Zealand, which will
have a great improvement in accessibility to
the German market of 80 million inhabitants.
Urban systemThe Fehmarnbelt Region’s urban system is
structured with a number of large heavy
centres within and outside the region as
important nodes (co-ordinating network
centres). The Øresund City and Hamburg are
crucial for the region’s function, activity level,
role as a hinterland for Copenhagen and
Hamburg, Lübeck and Kiel will create new
opportunities for what is today regarded as
peripheral areas in Lolland-Falster and in the
North East Schleswig- Holstein. Similarly, the
tourist market and the market for border
localisation will react to the new found
accessibility. This also means significantly
more realistic efforts within the European
Union’s range of border regional policies.
Logistic changeCopenhagen Airport is the leading air traffic
centre for Denmark and large parts of
Northern Europe – and since the opening of
the Øresund Bridge, Southern Sweden is part
of the local hinterland. Traffic across the
Øresund Bridge reflects the increasing
integration of Greater Copenhagen–Malmö-
Lund. Due to the short and frequent ferry
services between Helsingborg and Elsinore,
this border area is also displaying some signs
of integration. The Fehmarnbelt currently
shows no evidence of developing cross-border
systems except within some retail areas driven
by price differences.
The network position of the two major
conurbations within the Fehmarnbelt region –
Copenhagen and Hamburg is of high quality.
Hamburg is the second harbour of the
European continent with a global network of
lines, whilst the harbours of the Øresund
region plays more modest roles with feeder
traffic as their mission. When it comes to land
traffic Hamburg is the North German hub for
Figure 8. On the German side
the proposal is to make the
approach area as green as
possible and thus integrate it
into the existing landscape as
much as possible.
The Fehmarnbelt Tunnel : Regional Development Perspectives 11
come from the Lübeck area in Schleswig-
Holstein. In the Danish and Swedish parts of
the region, Copenhagen and adjoining areas
attract most of the commuting from the
surrounding areas, i.e., 66,500 commuters.
74 per cent of regional commuters into the
metropolitan area of Copenhagen come from
Region Zealand with 26 per cent from Scania.
The many commuters from Scania to
Copenhagen are largely a result of the
increased integration between Denmark and
Sweden that followed in the wake of the
opening of the Øresund Bridge in 2000.
The urban system within and close to the
Fehmarnbelt region includes a number of
other centres. There are other large cities of
which some with larger or smaller justification
claim metropolitan status. Three large German
cities are found on a somewhat lower level in
the urban hierarchy than the Øresund City,
Hamburg and Berlin. They consist of the
special ised centres Braunschweig–Wolfsburg,
Hannover and Bremen and are overshadowed
by Hamburg but nevertheless play strong
independent roles as industrial centres,
meeting places and gateway cities.
The region’s urban system is also structured
by a number of other major cities that play
the role as regional centres with a strong
concentration of hinterland-oriented public
service activities. Most of these cities have a
university, some have gateway function and
all have considerable industrial niches. As part
of the picture, there are a series of medium-
sized cities in the Fehmarnbelt region whose
roles are mainly local although a few like
some of the major centres also function as a
supplement to, and interact with, the larger
gateway cities.
Commuting and labour marketCommuting statistics reveal that the region’s
Pakistan 9870 Saint Vincent and the Grenadines 5220 Qatar 3680
Iran 9850 Laos 5190 Saint Lucia 3670
were made for size of country, length of
coastline, or degree of industrialisation.
The searches were conducted only in English.
Testing the results with a comparable
nonsense search phrase suggests that results
of 10,000 or less generally indicate little or
no sediment management activity within a
country. Results of 6,000 or less appear to
be “noise” in the search results.
Quality standards related to dredgingAs of March 2010, about 35 countries appear
to have some type of regulatory framework
relating to contaminated sediment
management, primarily in the form of
environmental quality standards related to
dredging. Many of these frameworks are
relatively new, appearing to have been
promulgated within the past decade.
And only a few of them appear to be more
than guidance; strict requirements for cleanup
are not prevalent. About the same number of
countries (largely, but not exclusively, the
same countries) appear to have some type of
technical framework available to evaluate risks
from sediment contamination.
The technologies employed tend significantly
toward removal (dredging) and off-site
disposal. A small minority of countries appear
to be intentionally employing techniques other
than dredging, such as capping or monitored
natural recovery (Figure 2).
oBseRVAtIons Although we have made significant progress
over the past 30 years, the challenges seem
daunting. We are still struggling to find the
best way to apply a scientifically sound, risk-
based approach to the screening and cleanup
of contaminated sediment sites. A diversity of
approaches exists and these are often used
and sometimes combined in less than
scientific ways.
In many cases, guidance on concentrations
intended for screening of sites is applied as
clean up criteria resulting in overly
conservative approaches. We are engaged in a
debate over the relative merits of the
watershed approach to contaminated
sediment management (Apitz et al. 2006)
and an approach more focussed on cleanup
of sediment contamination hot-spots.
The former approach articulates the value of
management of sediments within an entire
watershed in mind while the latter approach
seeks to address sediment contamination on
a smaller scale, typically in proximity to legacy
sources of industrial pollution. Thus far, we
have not found a highly effective and
reasonably priced “silver bullet” technology for
sediment treatment (Van der Laan et al. 2007).
New contaminants, such as personal care
products and pharmaceuticals, are presenting
themselves faster than we have been able to
address the classic contaminants of mercury,
polychlorinated biphenyls, and pesticides.
And the more experts press for source control
to prevent the recontamination of sediment
after cleanup, the more the realisation dawns
that the runoff from our agricultural and
urban settings, as much as from any industry,
is also responsible for sediment
contamination.
PHILIP A. SPADARO
is a leading international expert in
sediment cleanup and waterfront
redevelopment and a Senior Vice President
in the Waterfront and Sediment Group
of ARCADIS. He has degrees in chemistry
and geophysical sciences and more than
26 years of experience applying his
expertise and management skills to
projects where sediment quality is a
prominent issue. As the senior scientist in
the Waterfront and Sediment Group, he
advises ARCADIS’s clients and coordinates
sediment management and remediation
projects worldwide.
APPRoAcHSearch criteria were developed for generating
an informal Internet “snapshot” of the state
of contaminated sediment issues around the
world in 2010. For each of 196 countries
(the 192 member states of the United Nations
plus Kosovo, Palestine, Taiwan, and Vatican
City), a phrase in the format of “country +
contaminated sediments” was searched, and
the number of results was recorded. Results
for this type of search are of course qualitative
and time-dependent.
The searches were conducted over a few days
in March 2010 so the results would be
contemporaneous and internally consistent.
The tabulated results are presented in Table I.
Using the results from these initial searches,
key documents were identified and reviewed
to address the larger regulatory and technical
questions. The results of this review are
presented in Table II and depicted graphically
on Figure 1. The figure and tables are color
coded to indicate countries with both
regulatory and technical frameworks (green),
countries with one or the other (red),
and countries with neither (gray).
FInDInGsInternet search results vary from a high of
239,000 (United States of America) to a low
of 1,490 (Andorra). The results make intuitive
sense, with countries having well-known
sediment management programmes producing
more Internet search results. No allowances
Remediation of Contaminated Sediment : A Worldwide Status Survey of Regulation and Technology 17
Figure 2. Remedial design at the Thea Foss Waterway,
Tacoma Washington, USA included evaluations of
source control measures and potential disposal sites,
natural recovery analysis, cap, dredging and confined
disposal facility designs, a hydrographic survey and
habitat mitigation plans.
18 Terra et Aqua | Number 123 | June 2011
United States of America
Yes Yes d, c, nr, ss, sp, it, et, b 239000 Linkov 2006
Canada Yes Yes d, c, nr, ss, sp, it, et 133000 Canadian Council of Ministers of the Environment 1999, 2001, Sydney Tar Ponds Agency 2010, British Columbia Laws, 2003
United Kingdom Yes d, c 106000 Brewer 1997
Germany Yes Yes d, c, ss, l, sp, it, et, b 85400 Federal Ministry for the Environment, Nature Conservation and Nuclear Safety 1998, Löser 2001
China (PRC) Unknown Yes d 76900 Liu 1999, Chen 2007
Japan Yes Yes d, c, ss, sp, it, et 74800 Ministry of the Environment - Japan 1994, Hosokawa 1993
Australia Yes Yes d 70700 Department of Environment and Conservation, 2003, Guerin 2001, Rae 2006, New South Wales Consolidated Acts, 1997
Netherlands Yes Yes d, c, nr, ss, l, sp, it, et, b 67900 Ministry of Housing, Spatial Planning and the Environment 1998, 2009
and Sanborn, H.R. (1985). “Bioavailability and Bio-
transformation of Aromatic Hydrocarbons in Benthic
Organisms Exposed to Sediment from an Urban Estuary.”
Environmental Science and Technology, 19, 836.
Vervaeke, P., Luyssaert, S., Mertens, J., Meers, E.,
Tack, F.M.G., and Lust, N. (2003). “Phytoremediation
prospects of willow stands on contaminated sediment:
a field trial.” Environmental Pollution, 126 (2). Elsevier
(275-282).
Wildi, W., Dominik, J., Loizeau, J., Thomas, R.L.,
Favarger, P., Haller, L., Perroud, A., and Peytremann, C.
(2004). “River, reservoir and lake sediment
contamination by heavy metals downstream from
urban areas of Switzerland.” Lakes & Reservoirs:
Research and Manage ment, 2004 (9). Blackwell
Publishing, Oxford, UK (75-87).
24 Terra et Aqua | Number 123 | June 2011
tHe IMPoRtAnce oF BeD MAteRIAL cHARActeRIsAtIon In PLAnnInG DReDGInG PRoJects
MIcHAeL P. costARAs, R.n. BRAY, RIcHARD P. LeWIs AnD MARK W.e. Lee
ABSTRACT
Practical experience of dredging projects has
demonstrated the importance of understanding
the nature and composition of seabed material
before dredging starts. The dredging industry
strongly encourages clients to undertake
detailed geotechnical investigations at an early
stage in project design to avoid any expensive
“surprises” once work starts. Despite this,
mainstream engineering consultants are not
taking specialist advice and proponents are not
being advised about what to do, nor does it
appear that dredging contractors and specialist
consultants are being consulted at an early
enough stage in project development.
Attempts to make very minor cost savings
early in a project by undertaking inadequate
sampling and testing of bed materials routinely
leads to serious project problems with
significant consequences in terms of project
schedule, project cost and company profit.
Consequently, the reputation of the dredging
industry suffers and the perception of
dredging being a claim-ridden activity persists.
This article focusses on when, how and why
projects suffer as a consequence of
inadequate sampling and testing of bed
materials. Having identified the problems
guidelines are set out to allow these to be
avoided in the future. This article is based on
a paper which appeared in the Proceedings of the WODCON XIX in Beijing, China in
September 2011 and has been published
here in a revised version with permission.
INTRODUCTION
When planning dredging projects, a key factor
is the ability to describe the site and define
the nature of the ground. This information,
together with physical, environmental,
operational, statutory and legal constraints
provide the tendering Contractor vital
information which, in conjunction with the
Specification, helps the Contractor understand
what work has to be done.
There is little doubt that the importance of
accurate and comprehensive geotechnical
information is necessary to facilitate the design
and execution of any construction project
(Figure 1). However, time and again it is found
that insufficient, inaccurate and irrelevant data
are used to inform dredging projects.
The purpose of this article is to address factors
that are of specific relevance to dredging
rather than maritime structures as a whole,
and which therefore have a significance that
may not be recognised when planning the
development of a maritime project. Model
results are used to help illustrate the points
made within the article.
24 Terra et Aqua | Number 123 | June 2011
Above: A geotechnical site investigation for a major
marine development with, nearshore, a small elevated
platform for geotechnical sampling through a shallow
rock seabed and, offshore, a landing craft for soils
sampling in excess of 5 m water depth. Characterising
bed material prior to dredging is essential.
Figure 1. Close-up of the elevated platform for
geotechnical sampling through a shallow rock seabed.
The Importance of Bed Material Characterisation in Planning Dredging Projects 25
Whilst many examples of bad practice (and
resultant delays, costs and legal action) exist,
discussion of specific projects is not considered
appropriate and is not undertaken here.
For any dredging project, the understanding
of the bed material, its variability, how it
behaves when it is dredged, transported,
placed or enters the water column is vital to
determining how best to dredge it and how
best to mitigate impacts both in the near and
far field.
WHAt Is WRonGDredging works are frequently a component
of a large maritime engineering development
scheme, such as a new harbour, barrage or
immersed tube crossing. Dredging is perceived
as being a simple operation, far less complex,
in terms of design, than berthing structures,
barrages, locking structures and immersed
tubes. In some ways the dredging design is simple and this traps the design engineer into
thinking that the dredging activity is less
important than other construction activities
in the project. This is not so; it is quite the
opposite in fact.
The value of the dredging work often equals
and may exceed the value of the other works
being carried out. A small change in the sub-
soils along a berthing line may cause there to
be increases in construction cost because of
the need to lengthen piles or carry out soil
replacement. A similar small change in the
sub-soil in the dredging area may have a
profound effect on dredging productivity and
cost the contractor 10% or 15% more – which may be the difference, for the dredging
contractor, in making a profit or loss on the
project. In some cases, where for instance
environmental sensitivities are heightened, the
costs or impact of the differences may be far
more fundamental – possibly bringing the
works to a halt until the problems have been
overcome.
Another factor that influences the amount of
preliminary sub-soil investigation carried out
for dredging works is that this type of work is
expensive and moderately difficult to execute
with the necessary quality, both on site and
during laboratory testing. Clients are thus
faced with significant expenditure upfront,
sometimes on a project that only has a slim
chance of getting past the planning stages.
They are naturally reticent about spending this
risk money. This makes it difficult for design
engineers to convince clients that they should
spend money upfront. One objective of this
article is to assist design engineers in
educating clients to understand the site
investigation needs for their work.
A third problem that is found is that the
design engineer is unaware of the factors that
influence the environmental effects of
dredging works. This is unsurprising. Dredging
itself is a sub-set of maritime civil engineering,
and the environmental effects of dredging are
a sub-set of dredging works. As a result,
specialist support is needed to understand the
site investigation requirements (Figure 2).
PLAnnInG A sIte InVestIGAtIon FoR DReDGInG WoRKsThe scope of the worksWhen site investigation works are going to be
expensive, such as in maritime sub-soil
investigation, a tiered approach to
investigation is recommended. This approach
has been described elsewhere (Bray 2008),
both in terms of the approach to the
investigation and the evaluation of the data
so collected. The intent is to reduce the
quantity of upfront expenditure in the initial
stages, so that only sufficient data are
collected to determine:
• determine whether the project is likely
to be technically and financially feasible;
• identify how more detailed investigations
can be tailored to suit both the project
envisaged and the ground conditions
found in the initial stage; and
• ensure that investigation methods, and
sample collecting and testing, are all
suitable in extent and relevant to the types
of dredgers to be used in the works.
Subsequently, further investigations can be
planned if it is determined that the project
is going forward. However, at this stage the
client is likely to be more favourably disposed
to carry out more extensive investigations,
because the project is moving forward and
the investigations are being moulded to the
type and nature of the project and the
construction methods likely to be needed.
For example, the initial investigations may
have shown that a seismic survey would
reduce considerably the cost of future
investigations, combined with only a limited
borehole campaign.
Figure 2. An acoustic instrument (Nortek AWAC, used for the measurement of currents and waves in the marine
environment, is one of many tools for gathering essential geotechnical information.
26 Terra et Aqua | Number 123 | June 2011
Focus of the investigationsWhen design engineers are considering the
information they require for a berthing
structure or reclamation area, the focus tends
to be on bearing strata and the compressibility
of any weak overlying soils. This is not so for
the dredging engineer or contractor, where
a number of other parameters are of vital
importance.
Firstly, the engineer/contractor needs to know
what type of dredger is best suited to the
materials on site and the method of excavating
and moving this material to its final destination.
Secondly, they need to evaluate how
productive the dredging equipment will be
and, finally, what the environmental effects of
the dredging works and construc tion methods
are likely to be. In addition, if the material is to
be used for some beneficial purpose, the
engineer will need to know whether its
characteristics have changed during the
dredging, transport and placing processes,
and, if so, what its final state is.
• Weak soils need to be collected with
minimum disturbance. Hence wash boring
is not particularly useful. Ideally, the
traditional shell and auger methods should
be used. Not only do they allow for
identification of every change of strata, but
samples taken during the boring, although
disturbed, are generally representative of
the material at the sampling depth;
• Vibrocoring is an alternative method for
obtaining information about weak material,
but it must be recognised that the depth of
investigation may be limited by the
maximum length of core recoverable
relative to the required dredge depth or
material that is too strong to be penetrated
(Figure 3);
• Weak soils need to be sampled and tested
frequently. It is almost always the case that
there are not enough samples or the testing
carried out has been limited. Engineers are
not just interested in a range of values.
They need to know how the strength and
size characteristics vary across the site
(Figure 4);
To carry out these evaluations, information
about both the strong and the weak materials
on the site is needed. Therefore the number
and locations of the boreholes, vibrocores or
other sampling methods used to investigate
and collect samples must be adjusted
accordingly. It is too prescriptive to suggest
a formula for determining the optimum
number of investigative points. These will be
determined by the overall geology of the site,
the sensitivity of the probable dredging
method and, to some extent the stage of the
development at that time.
A potential method for determining where
to focus marine site investigation resources is
given in the following section. Additional
information can also be gained by talking to
Dredging Contractors during the planning of
the site investigation works.
sAMPLInG AnD testInGSamplingThe following points are particularly relevant
when considering sampling:
Figure 3. A Vibrocorer in use during site investigation works.
Figure 4. Undertaking undisturbed soil sampling using a ship-mounted rotary drilling rig as part of
offshore site investigation works for a major marine development.
The Importance of Bed Material Characterisation in Planning Dredging Projects 27
• Detecting the variability of the materials on
the site is one of the most important
objectives of the site investigation;
• Correct logging of rock cores is vital.
The quality of the rock is as important as
its strength. Hence core recovery, RQD and
Fracture Index should be recorded on all
cores.
TestingTesting of samples needs to reflect the
sensitivity of the dredging method to changes
in soil or rock characteristics. For example, the
standard sieve sizes are not necessarily ideal for
testing loose granular materials, particularly
when hydraulic methods of excavation are
envisaged.
The shape of the PSD curve between 80 and
200 microns is very influential in determining
overflow losses from trailing suction hopper
dredgers (TSHD, see below) and the sizes
below 20 microns are also very important for
determining the fill characteristics of materials
and the permeability, which will affect
consolidation of fill.
Where soils or rocks are particularly weak,
it may be necessary to carry out specific tests
to assess degradation of dredged materials
during the dredging process or thereafter.
Testing of materials to determine the way in
which they break-up can be important for
two primary reasons:
1. there can be a very significant impact on
the losses from a dredging project and,
consequently, the likely environmental
impact (potentially affecting the viability
of the project); and
2. if the material is to be used for reclamation
then the design and construction of the
reclamation and the mechanical properties
of the fill will be very heavily influenced by
the character of the material which is
liberated by the dredging process.
Dredging has the potential to degrade bed
materials in different ways. These can be
summarised as follows:
a) Mechanical breakage where the plant
comes into contact with the bed (e.g., at
a cutter head or a backhoe bucket);
b) Impacts / contacts between clasts / particles
(e.g., in pumps and pipelines);
c) Material coming into contact with pipe and
pump surfaces; and
d) Flow of water around fragments / grains.
A number of established lab tests exist for
measuring the breakage / abrasion of rocks /
MICHAEL COSTARAS
is the Manager of the Dredging Group at
HR Wallingford. He has extensive
experience of estuary and marine
developments and port siltation and
specialises in the provision of dredging
impact assessments and dredging
contracts. He is a Board Member of the
International Board of the Central Dredging
Association (CEDA) and is a past Chairman
of the British Section Committee.
NICK BRAY
is a Consultant to HR Wallingford. He is
a dredging and reclamation specialist, with
a broad knowledge of maritime civil
engineering gained through his 44-year
involvement in the sector. With a
background in project management,
he has experience of both consulting
and contracting organisations. He was a
founder member of the British Section of
CEDA and has been a regular contributor
to the literature of dredging.
RICHARD LEWIS
is a Scientist within the Dredging Group
at HR Wallingford. He has a detailed
knowledge of coastal and estuarine
sediment dynamics and is experienced in
data manipulation and analysis, including
data quality control and the associated
limitations. He specialises in undertaking
dredger simulation modelling for projects
which require the development of dredging
strategies, the determination of likely
production rates and their associated costs.
MARK LEE
is a Principal Scientist in the Dredging
Group at HR Wallingford. He has a
background in marine monitoring and
surveying, and has over 13 years
experience during which time he has
specialised in coastal oceanographic
surveys and coastal and fluvial sediment
transport measurements. Mark has also
contributed to both vessel-based and
shore-based marine surveys. He has
worked extensively on projects in the
following sectors: dredging; construction;
energy; oil and gas and water.
Figure 5. Laboratory tumbling equipment is sometimes used to simulate the degrading of sediment during dredging.
28 Terra et Aqua | Number 123 | June 2011
granular material, these include:
• Los Angeles test
• Deval Test (aggregate attrition value)
• Micro-Deval test
• Aggregate Abrasion Value (AAV) test
• Polished Stone Value (PSV) test
• Slake Durability test
However, none of these tests has been
designed to assess the impact of dredging
processes on materials; instead they tend to
have origins in industries such as road
construction. As a consequence, none of the
tests represents well the physical conditions
that materials are subject to during dredging.
For example, both the Los Angeles test and
the Micro-Deval test both involve placing
samples in a rotating cylinder with steel balls,
while the Aggregate Abrasion Value test
involves pressing samples against the surface
of a steel disc while feeding with Leighton
Buzzard sand.
Previous studies of abrasion of both grains
and shelly material have shown that failure to
properly represent the physics that materials
are subject to can lead to unexpected /
incorrect results. Ngan-Tillard et al. (2009)
found that, using the French Micro-Deval test,
quartzitic sand suffered unexpectedly high
degradation as compared with carbonate sand
(the shape of the carbonate grains leading to
them being suspended away from the bottom
of the cylinder). The authors sought to
address this perceived anomaly by changing
the rotation speed and the character of the
steel balls used. Similarly, the use of tumbling
barrel experiments to simulate shell abrasion
in fluvial environments has been shown to
have serious shortcomings (Newell et al. 2007)
(Figure 5).
More representative, specifically designed,
tests are required to properly represent the
physical processes that materials are subject
to during dredging. In the absence of such
tests, existing laboratory methods should be
used with careful thought, thorough
procedures and caution.
exAMPLes oF sItUAtIons WHeRe sIte InVestIGAtIon ResULts ARe cRItIcALFor the examples presented in the following
section, costs have been developed using the
suite of HR Wallingford Dredging Research
0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000 10000
Grain size (microns)
% P
assi
ng
PSD A
PSD B
Figure 6(a). Parallel shift in PSD.
0
10
20
30
40
50
60
70
80
90
100
1 10 100 1000 10000
Grain size (microns)
% P
assi
ng
PSD C
PSD D
Figure 6(b). Rotational shift in PSD.
Table I. Cost uncertainty resulting from varied ground conditions
Item SandSoft Clay
Medium
Clay
Stiff Clay
WK Rock
MS Rock
VS Rock
Marine operations platformBase
Case+20% +10% same +10% +20% +30%
Berth Base
Case+20% +10% same +10% +20% +30%
TrestleBase
Case+20% +10% same +10% +20% +30%
BreakwaterBase
Case+50% +10% same same same same
Construction DockBase
Case+30% +10% same +5% +10% +20%
DredgingBase Case
+5% +10% +20% +100% +300% +500%
Shoreline protectionBase
Case+30% same same same same same
The Importance of Bed Material Characterisation in Planning Dredging Projects 29
Dredger Simulation Models. The HR
Wallingford Dredging Research Dredger
Simulation Models are a set of proprietary
models that take into account the physical
processes involved in the excavation and
transport of material for a variety of standard
dredge plant. Each model has the ability to
deal with operator controlled usage and
variable ground conditions to estimate
production. The costing modules use the soil
characteristics and production estimates
to develop wear rates and incorporate the
CIRIA Cost Standards for Dredging Equipment
(2009) to calculate the depreciation and
interest, maintenance and repair, insurances,
crew and fuel costs that all factor into the
cost of the plant and the unit rates produced.
Trailing suction hopper dredger (TSHD) operationsJust a small parallel shift in the particle size
distribution (PSD) of material being dredged
can have a marked effect on the cost and
execution of a dredging project. The example
is given whereby the initial site investigations
for a sand sourcing study are limited with only
a small number of samples taken to
characterise the area.
The results of PSD analysis identify an average
PSD akin to PSD A as shown in Figure 6(a).
The dredging contractor tenders for the work
and is successful on the basis of his price for
dredging PSD A. Throughout the execution of
the works the contractor discovers that the soils
being dredged are better described by PSD B in
Figure 6(a), a coarser PSD which produces a
higher quality fill. This puts the dredging
contractor in an advantageous position as he/
she will have to dredge less material in situ to
provide the same quantity of fill.
Assuming that PSD A and PSD B both have
the same characteristics (density, angularity
and mineralogical composition), this leads to
lower overall wear on the moving parts of the
dredger than had been budgeted for in the
tender price, but higher wear in the pipelines
ashore. Furthermore, the amount of material
lost through the overflow process will also be
reduced giving the contractor more freedom
to work unrestricted should there be any
environmental restrictions in place.
The differences in the required in situ
productivities to achieve the same fill output
are small (~ 5%) but in the context of a
€ 50M dredge contract this may amount to
a difference in excess of €2.5M, which in this
case would be an additional 50% profit to the
contractor.
This sensitivity is also present for a shift about
the D50
of the PSD as illustrated by PSD C and
PSD D in Figure 6(b), where the two average
soil PSDs have the same D50
, but a marginally
different amount of sorting. Thus, a similar cost
result is obtained if the degree of sorting of a
granular material is not assessed adequately.
Cutter suction dredger (CSD) operationsFor rock dredging projects, the impact of
poorly characterised materials has the
potential to have a far more significant impact
on the total cost and schedule of a dredging
project. Figure 5 shows rock strength
distributions obtained from two differently
targeted site investigations at the same site:
- The strength distribution obtained from
Investigation A is based around limited
geotechnical data in the dredge area and
comprehensive coverage around the piled
structures.
- The strength distribution obtained from
Investigation B is based upon a well-
targeted and comprehensive investigation
across all areas and clearly shows the
presence of stronger material that had been
missed by Investigation A.
Faulty testing equipment has also been known
to be another contributing factor towards
producing similar variations in testing results
as shown in Figure 7 (i.e., the rock strength is
biased downwards).
Investigation A
Investigation B
0 to 5
30 16
5 to 15
65 44
15 to 25
5 31
25 to 35
0 9
Distribution (%)
Unconfined
compressive strength (Mpa)
0
10
20
30
40
50
60
0 5 10 15 20 25 30 35
Unconfined compressive strength (MPa)
Nu
mb
er o
f re
sult
s
Investigation AInvestigation B
Figure 7. Two rock strength distributions from the same site.
30 Terra et Aqua | Number 123 | June 2011
Newell et al., (2007). “Bedload abrasion and the
in situ fragmentation of bivalve shells”.
Sedimentology, 54, 835-845.
Ngan-Tillard et al. (2009). “Index test for the
degradation potential of carbonate sands during
hydraulic transportation.” Engineering Geology,
108, 54-64.
If a comparison of costs is made, based upon
the results of Investigations A and B, the total
cost of dredging is 51% higher for the rock
strength distribution described by Investigation
B which would result in the filing of a
substantial claim against the client.
The effect of poor Site Investigation results in the context of the overall projectA typical Phase 1 LNG project (up to 8 MTPA)
may consist of two berths, one marine
operations platform and a 2.5 km trestle,
1300 m of breakwater in 10 m water depth
and 15M m3 of dredging. In total this may
amount to an investment of approximately
US$ 1 billion. The figures shown in Table I are
based on a cost analysis of several Phase 1
LNG projects around the world.
Table I illustrates the cost sensitivity of the
individual engineering components of a typical
Phase 1 LNG project to variations in ground
conditions relative to a base case condition.
Table I clearly demonstrates that the potential
variability in cost and the level of risk linked to
each individual engineering component is the
most significant for dredging. The examples
presented above show the importance of
undertaking adequate site investigations to
inform the tendering process and highlighted
the relevance for both client and contractor.
Based upon the figures presented in Table I,
and bearing in mind that the monetary value
of the dredging works could represent 50%
of the cost of the marine works, the current
definition of an “adequate” site investigation
for dredging should be revised. This article
suggests that the design engineer should
weight geotechnical investigations such that
the number of cores drilled is biased towards
characterising the areas to be dredged.
Involving the Contractor early on is one of
the ways of developing the right focus for
these investigations. Alternatively, a procedure
should be adopted that results in the engineer
allocating a sufficiently high enough number
of boreholes in the dredging area to permit a
reasonable estimate of the cost of dredging to
be made. This could be based on a system
that takes account of the rough estimates of
the values of the marine components of the
project (see Figure 8).
REFERENCES
Bray, R.N. (Editor) (2008). Environmental Aspects of
Dredging. CEDA-IADC-Taylor and Francis, Leiden,
The Netherlands.
Bray, R.N. (2009). A guide to cost standards for
dredging equipment 2009. CIRIA, London, UK.
Is Geology Complex?
Is Seismic Investigation Feasible?
Plan Site Investigation and Seismic Survey to Suit Overall Ground Conditions
Produce Rough Costing of Marine Components
Split Between Value of Jetty and Dredging
Propose Number of Boreholes to Suit Budget Available
YES
NO
YES
NO
Figure 8. Proposed system to define the number of boreholes to characterise dredged areas relative to other marine
components.
CONCLUSIONS
Bed material characterisation for dredging
projects is a significant factor in defining how
dredging works will be undertaken. It also
demands an understanding of the dredging
process and how this influences/impacts both
the marine environment and areas where
dredged material is placed – intentionally or
otherwise.
Comprehensive geotechnical information is
important for any construction project. How
this is collected, assessed and extrapolated is
vital to understanding the risk associated
with dredging works and ensuring the right
equipment is selected first time. This requires
an acceptance that the requirements of a
dredging site investigation are not the same
as those for a construction project. Further,
it demands a change in the mindset away
from the idea that any site investigation
should be developed proportionally to the
capital investment per unit area for the
project as a whole.
Recognising that the comprehensive all-
embracing site investigation is a utopian ideal,
this article highlights the key attributes of
soils that need to be determined and where
testing should be focussed. It explains the
significance of material characteristics in
the context of TSHD and CSD operations.
Following on from this, it highlights a
weighting or procedural approach to
focussing the marine site investigation
resources and encourages project owners
to consult dredging contractors and specialist
consultants at an early stage in project
development.
Books / Periodicals Reviewed 31
UnDeRstAnDInG seA-LeVeL RIse AnD VARIABILItYEditEd by John A. ChurCh, PhiliP l. WoodWorth, thorkild AAruP And W. StAnlEy WilSon428 pp. Wiley-Blackwell Publishers. Colour illustrations. 2010. ISBN: 978-1-4443-3452-7 (hardcover). ISBN: 978-1-4443-3452-4 (paperback).
In June 2006, the World Climate Research Programme (WCRP),
responding to the work of the Intergovernmental Panel on Climate
Change (IPCC), organised a workshop in Paris, France that brought
together the world’s specialists on the science of sea-level change.
The core motivation for the workshop was the ever-increasing
population growth along coastal zones, combined with the
assessment of IPCC that sea-level rise is also continuing. The aim of
the workshop was to identify “the major uncertainties associated with
sea-level rise and variability, as well as the research and observational
activities need for narrowing those uncertainties…”.
After examining all aspects of sea-level rise, the workshop determined
uncertainties in the knowledge of contributing factors and generated
a summary set of recommendations focussed on reducing those
uncertainties. Many of the recommendations made by the workshop
seek to guide ongoing research that should be enhanced, including a
10-Year Implementation Plan for the Global Earth Observation System
of Systems (GEOSS). Other recommendations encourage open data
sharing, data archaeology, and better use of data already in hand.
Finally new needs based on emerging science and technological
development were ascertained.
The book reflects the discussions and deliberations of some 163
scientists from 29 countries who attended the workshop and their
assessments of our current understanding of sea-level rise.
The expressed hope of the book is to help set priorities for future
research and to help governments, industry and society to formulate
sound policy to respond to greenhouse gas concentrations and sea-
level rise and their consequences.
The supporting organisations, in addition to WCRP, were the World
Meteorological Organization (WMO), the Intergovernmental
Oceanographic Commission (IOC) of UNESCO and the International
Council for Science (ICSU). In addition, a multitude of international
organisations and agencies have sponsored and participated in
making the workshop and the book a reliable and definitive
contribution to the literature on this sometimes controversial subject.
Approximately one hundred authors from a wide range of institutions,
research laboratories and universities have contributed to the text.
The basic point of departure of the book (and the reason for the
workshop) is that coastal zones have changed profoundly during
the 20th century with increasing populations, economies and
urbanisation. About 10% of the world’s population today live in
coastal zones below 10-metres elevation. Adding up the populations
of the 136 port cities around the world with more than 1 million
inhabitants comes to a total of 400 million people. About 10% of this
population are exposed to the possibility of a 1-in-100-year coastal
flood event. Clearly, given the attractiveness of living near water,
coastal development is not about to cease, and thus society is
becoming increasingly vulnerable to the effects of sea-level rise and
variability, as witnessed by the tsunami in Southeast Asia in 2004,
Hurricane Katrina in New Orleans in 2005 and the recent tsunami
in Japan where the consequences are yet to be overseen.
The underlying principle guiding the book is that “Improved
understanding of sea-level rise and variability is required to reduce
the uncertainties associated with sea-level rise projections, and hence
to contribute to more effective coastal planning, management and
adaptation in the presence of the many pressures on coastal regions”.
This theme of uncertainty is evident starting in Chapter 1,
the Introduction, which gives an overview of the coastal situation
globally – including many colour photographs depicting highly dense
coastal populations, erosion episodes and measurement techniques.
Chapter 2, Impacts and Response to Sea-Level Rise, and Chapter 3,
A First-Order Assessment of the Impact of Long-Term Trends in
Extreme Sea Levels on Offshore Structures and Coastal Refineries, give
insight into the vulnerabilities of coastal communities and the need for
adaptation and mitigation and improved understanding of sea-level
rise in order to reduce costs associated with sea-level rise.
This requires improving observation and modelling of the oceans,
glaciers and ice caps and of the Greenland and Antarctic Ice Sheets.
Detecting early signs of any growing ice sheet contributions is critical
to decision-making about the required level of greenhouse gas
mitigation and adaptation planning. These chapters form the basis for
why the research presented in subsequent chapters is so necessary
and should be continued and in fact enhanced.
BooKs / PeRIoDIcALs ReVIeWeD
32 Terra et Aqua | Number 123 | June 2011
Chapter 4, Paleoenvironmental Records, Geophysical Modeling, and
Reconstruction of Sea-Level Trends and Variability on Centennial and
Longer Timescales, approaches the subject with the aim of reducing
some of the uncertainties that arise during research. The fact is that
global mean sea level has always changed. But putting it in a historical
context, research which looks at glacial cycles in the last million years
gives evidence for observing the phenomena today. According to
researchers, “sea level has oscillated by more than 100 metres as the
ice sheets, particularly those of northern Europe and North America,
waxed and waned”. Paleo data indicates rates of sea-level rise of
about 6 to 9 m per millenia with sea level reaching 6-9 m above
present day values and with polar temperatures about 3°C to 5°C
higher than today. Over the following 100,000 years sea levels fell
until about 20,000 years ago until about 7,000 years ago the ice
sheets collapsed. Thereafter sea level rose rapidly for many millennia,
with peak rates during the deglaciation potentially exceeding several
metres per century. From about 6000 to 2000 years ago, and up to
the 18th century, sea level rose more slowly. Predictions for the latter
part of the 21st century are for global temperatures similar to those
that occurred about 125,000 years ago.
Chapter 5, Modern Sea-Level Change Estimates, presents the more
precise observational techniques that have been developed recently
which have led to new conclusions about sea-level rise. For instance,
by examining coastal sediment cores and other paleo sea-level data,
the indication is that “the rate of sea level rise has increased since
1993, with a rate of over 3 mm/year, greater than any similar length
period during the 20th century”.
Whilst it is not always clear why sea level is rising, this chapter presents
a broad approach to the many different physical processes contributing
to sea level change, such as the melting of glaciers and ice caps and
upper ocean thermal expansion, as well as some contributions from
deep-ocean thermal expansion and the ice sheets. Sea level also
changes as a result of storage of water in dams and extraction of
water from aquifers. The chapter also examines the use of satellite
altimetry to measure changes in the ocean and ice sheet volume,
satellite gravity to measure changes in ocean and ice sheet mass.
Chapter 6, Ocean Temperature and Salinity Contributions to Global
and Regional Sea-Level Change, also addresses the uncertainties of
previous measurements and new methods such as Argo profiling
floats to measure changes in upper-ocean temperatures and thermal
expansion which since 2003 have led to improved understanding of
the sea-level. Of particular concern is the rapid dynamic thinning of
the margins of the Greenland and Antarctic Ice Sheets. But with
FActs ABoUtDReDGInG ARoUnD coRAL ReeFsINTERNATIONAL ASSOCIATION OF DREDGING COMPANIESAn Information Update from the IADC. Number 1-2011. 4 pp. Available free of
charge online and in print.
Facts About Dredging Around Coral Reefs was published this spring as part of
the IADC series of concise, easy-to-read “management summaries” on specific
dredging and maritime construction subjects.
Since coral reefs are one of our most valuable marine assets and, one which
dredging projects often encounter, they often become a subject of concern.
Although coral reefs are robust and can withstand the forces of storms, climatic
change, sea level changes and predators, they are still vulnerable and sensitive
to their surroundings. Healthy coral reefs provide food, protect shorelines and
support the livelihoods of local communities such as fishing and tourism.
Unhealthy coral reefs can have a negative socio-economic impact.
Studying the interrelationship between dredging activities and coral reefs has
become crucial as the rapid development of our coastal infrastructure with
ports, waterways, land reclamation and beach nourishment increases.
These necessary economic developments can impact coral reefs and cause
disturbances in their ecosystem thus giving the impression that economic
growth is in conflict with environmental considerations. To ensure that this is
not the case, close examination of the coral reefs and potential impacts must
be conducted in a timely matter. Transparency and clarity must be achieved
through systematic evaluations to determine what can and should be done,
taking into consideration that not all impacts are permanent or detrimental,
and some risks can certainly be avoided by sound strategic planning.
Facts About Dredging Around Coral Reefs offers suggestions for the best
technical practices that can be used to prevent, minimise, mitigate or
compensate for impacts incurred when dredging is schedule to take place in
the vicinity of coral reefs. For instance, site investigations, an Environmental
Management Plan and continuous monitoring can reduce risks considerably.
Achieving a successful dredging project in a sensitive coral reef environment
demands that all parties think ahead and cooperate.
In the foreground a small elevated platform for geotechnical sampling through a shallow rock seabed and in the background
a landing craft for soils sampling in excess of 5 m water depth. Conducting a detailed geotechnical site investigation is crucial
to the execution of a successful project, therefore, dredging contractors and consultants need to be involved early on so as to
avoid expensive “surprises” once work starts (see page 24).
TERRA ETAQUA
Guidelines for Authors
Terra et Aqua is a quarterly publication of the International Association of Dredging Companies,
emphasising “maritime solutions for a changing world”. It covers the fields of civil, hydraulic
and mechanical engineering including the technical, economic and environmental aspects
of dredging. Developments in the state of the art of the industry and other topics from the
industry with actual news value will be highlighted.
• As Terra et Aqua is an English language journal, articles must be submitted in English.
• Contributions will be considered primarily from authors who represent the various disciplines
of the dredging industry or professions, which are associated with dredging.
• Students and young professionals are encouraged to submit articles based on their research.
• Articles should be approximately 10-12 A4s. Photographs, graphics and illustrations are
encouraged. Original photographs should be submitted, as these provide the best quality.
Digital photographs should be of the highest resolution.
• Articles should be original and should not have appeared in other magazines or publications.
An exception is made for the proceedings of conferences which have a limited reading public.
• In the case of articles that have previously appeared in conference proceedings, permission
to reprint in Terra et Aqua will be requested.
• Authors are requested to provide in the “Introduction” an insight into the drivers (the Why)
behind the dredging project.
• By submitting an article, authors grant IADC permission to publish said article in both the
printed and digital version of Terra et Aqua without limitations and remunerations.
• All articles will be reviewed by the Editorial Advisory Committee (EAC). Publication of an
article is subject to approval by the EAC and no article will be published without approval
of the EAC.
MEMbERShip liST iADC 2011Through their regional branches or through representatives, members of IADC operate directly at all locations worldwide
AfricAVan Oord Dredging and Marine Contractors, Luanda, Angola Boskalis International Egypt, Cairo, EgyptDredging and Reclamation Jan De Nul Ltd., Lagos, NigeriaDredging International Services Nigeria Ltd, Ikoyi Lagos, NigeriaNigerian Westminster Dredging and Marine Ltd., Lagos, NigeriaVan Oord Nigeria Ltd, Victoria Island, Nigeria
AsiABeijing Boskalis Dredging Technology Co. Ltd., Beijing, P.R. ChinaVan Oord (Shanghai) Dredging Co. Ltd, Shanghai, P.R. ChinaVan Oord Dredging and Marine Contractors bv Hong Kong Branch, P.R. ChinaBoskalis Dredging India Pvt Ltd., Mumbai, IndiaInternational Seaport Dredging Private Ltd., New Delhi, IndiaJan De Nul Dredging India Pvt. Ltd., IndiaVan Oord India Pte Ltd, Mumbai, IndiaP.T. Boskalis International Indonesia, Jakarta, IndonesiaPT Penkonindo LLC, Jakarta, IndonesiaPenta-Ocean Construction Co. Ltd., Tokyo, JapanToa Corporation, Tokyo, JapanHyundai Engineering & Construction Co. Ltd., Seoul, KoreaVan Oord Dredging and Marine Contractors bv Korea Branch, Busan, Republic of KoreaVan Oord (Malaysia) Sdn Bhd, Selangor, MalaysiaVan Oord Dredging and Marine Contractors bv Philippines Branch, Manilla, PhilippinesBoskalis International Pte Ltd., SingaporeDredging International Asia Pacific (Pte) Ltd., SingaporeJan De Nul Singapore Pte. Ltd., SingaporeVan Oord Dredging and Marine Contractors bv Singapore Branch, SingaporeZinkcon Marine Singapore Pte. Ltd., SingaporeVan Oord Thai Ltd, Bangkok, Thailand
AusTrAliA + NEW ZEAlANDBoskalis Australia Pty, Ltd., Sydney, AustraliaDredeco Pty. Ltd., Brisbane, QLD, AustraliaJan De Nul Australia LtdVan Oord Australia Pty Ltd., Brisbane, QLD, AustraliaWA Shell Sands Pty Ltd, Perth, AustraliaNZ Dredging & General Works Ltd, Maunganui, New Zealand
EuropEBaggerwerken Decloedt & Zoon NV, Oostende, BelgiumDEME Building Materials NV (DBM), Zwijndrecht, BelgiumDredging International N.V., Zwijndrecht, BelgiumJan De Nul n.v., Hofstade/Aalst, BelgiumBoskalis Westminster Dredging & Contracting Ltd., CyprusBoskalis Westminster Middle East Ltd., Limassol, CyprusVan Oord Middle East Ltd, Nicosia, CyprusRohde Nielsen, Copenhagen, DenmarkTerramare Eesti OU, Tallinn, EstoniaTerramare Oy, Helsinki, FinlandAtlantique Dragage Sarl, St. Germain en Laye, FranceSociété de Dragage International ‘SDI’ SA, Lambersart, FranceSodraco International S.A.S., Lille, France Sodranord SARL, Le Blanc-Mesnil Cédex, FranceBrewaba Wasserbaugesellschaft Bremen mbH, Bremen, GermanyHeinrich Hirdes G.m.b.H., Hamburg, GermanyNordsee Nassbagger-und Tiefbau GmbH, Bremen, GermanyVan Oord Gibraltar Ltd, GibraltarIrish Dredging Company, Cork, IrelandVan Oord Ireland Ltd, Dublin, IrelandBoskalis Italia, Rome, Italy
Dravo SA, Italia, Amelia (TR), ItalySocieta Italiana Dragaggi SpA ‘SIDRA’, Rome, ItalyBaltic Marine Contractors SIA, Riga, LatviaDredging and Maritime Management s.a., Steinfort, LuxembourgDredging International (Luxembourg) SA, Luxembourg, LuxembourgTOA (LUX) S.A., Luxembourg, LuxembourgAannemingsbedrijf L. Paans & Zonen, Gorinchem, NetherlandsBaggermaatschappij Boskalis B.V., Papendrecht, NetherlandsBoskalis B.V., Rotterdam, NetherlandsBoskalis International B.V., Papendrecht, NetherlandsBoskalis Offshore bv, Papendrecht, NetherlandsDredging and Contracting Rotterdam b.v., Bergen op Zoom, NetherlandsMijnster zand- en grinthandel bv, Gorinchem, NetherlandsTideway B.V., Breda, NetherlandsVan Oord ACZ Marine Contractors bv, Rotterdam, NetherlandsVan Oord Nederland bv, Gorinchem, NetherlandsVan Oord nv, Rotterdam, NetherlandsVan Oord Offshore bv, Gorinchem, NetherlandsDragapor Dragagens de Portugal S.A., Alcochete, PortugalDravo SA, Lisbon, PortugalBallast Ham Dredging, St. Petersburg, RussiaDravo SA, Madrid, SpainFlota Proyectos Singulares S.A., Madrid, SpainSociedade Española de Dragados S.A., Madrid, SpainBoskalis Sweden AB, Gothenburg, SwedenDredging International (UK) Ltd., Weybridge, UKJan De Nul (UK) Ltd., Ascot, UKRock Fall Company Ltd, Aberdeen, UKVan Oord UK Ltd., Newbury, UKWestminster Dredging Co. Ltd., Fareham, UK
MiDDlE EAsTBoskalis Westminster Middle East Ltd., Manama, BahrainBoskalis Westminster (Oman) LLC, Muscat, OmanBoskalis Westminster Middle East, Doha, QatarMiddle East Dredging Company (MEDCO), Doha, QatarBoskalis Westminster Al Rushaid Co. Ltd., Al Khobar, Saudi ArabiaBoskalis Westminster M.E. Ltd., Abu Dhabi, U.A.E.Gulf Cobla (Limited Liability Company), Dubai, U.A.E.Jan De Nul Dredging Ltd. (Dubai Branch), Dubai, U.A.E.National Marine Dredging Company, Abu Dhabi, U.A.E.Van Oord Gulf FZE, Dubai, U.A.E.
ThE AMEricAsBoskalis International bv Sucural Argentina, Buenos Aires, ArgentinaCompañía Sud Americana de Dragados S.A, Buenos Aires, ArgentinaJan De Nul do Brasil Dragagem LtdaVan Oord ACZ Marine Contractors bv Argentina Branch, Buenos Aires, ArgentinaVan Oord Dragagens do Brasil Ltda, Rio de Janeiro, BrazilVan Oord Curaçao nv, Willemstad, CuraçaoDragamex SA de CV, Coatzacoalcos, MexicoDredging International Mexico SA de CV, Veracruz, MexicoMexicana de Dragados S.A. de C.V., Mexico City, MexicoCoastal and Inland Marine Services Inc., Bethania, PanamaDredging International de Panama SA, Panama Westminster Dredging Overseas, TrinidadStuyvesant Dredging Company, Louisiana, U.S.A.Boskalis International Uruguay S.A., Montevideo, UruguayDravensa C.A., Caracas, VenezuelaDredging International NV - Sucursal Venezuela, Caracas, Venezuela
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