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INTERNATIONAL ASSOCIATION OF DREDGING COMPANIES

International Journal on Public Works, Ports & Waterways Developments

Number 67 - June 1997

Terra et Aqua – Number 67 – June 1997

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 thedevelopment of ports and waterways, and in particular, the associated dredging work.The name Terra et Aqua is a registered trademark.

EditorMarsha R. Cohen

Editorial Advisory CommitteeH. van Diepen, ChairmanJ. Boeter H. de Vlieger E.A.M. StraussH. Fiers C. Paris Solas P.G. RolandP.J.A. Hamburger

Editorial AddressTerra et AquaDuinweg 212585 JV The Hague, The NetherlandsTel. 31 (70) 352 3334Fax 31 (70) 351 2654

Please address inquiries to the editor.Articles in Terra et Aqua do not necessarily reflect the opinion of the IADC Board or of individual members.

© 1997 IADC, The NetherlandsAll 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.

Front cover:Without the intervention of dredging to construct a dam, the coastal zone of the isle of Texel, in the north of The Netherlands, would continue to erode as it has for more than a century (see page 3).

IADCDuinweg 212585 JV The Hague, The NetherlandsTel. 31 (70) 352 3334Fax 31 (70) 351 2654 International Association of Dredging Companies

2 Editorial

3 Seaward Coastal Defence Scheme Eierland

D. Rakhorst, D. de Wilde and C. Schot

Working with the Dutch Ministry of Transport, Public Works and Water Management,dredgers construct a dam as a means to prevent coastal erosion.

14 Dredging for Development (Fourth Edition)

Charles W. Hummer, Jr., Editor

A new edition of this classic manual on dredging in developing countries, with new illustra-tions and an emphasis on environmental issues.

15 2nd Asian and Australasian Ports and Harbours Conference

The second regional conference of the Eastern Dredging Association is held in Ho Chi Minh City, Vietnam.

16 Management of Dredged Material in Germany; a Compromise between

Economy and Ecology

Harald F. Köthe

New environmental priorities demand the development of new German guidelines for theplacement of dredged materials.

26 International Seminars on Dredging and Reclamation 1997

After Singapore and Delft, the next location of this weeklong course will be Buenos Aires,Argentina in October.

27 Books/Periodicals Reviewed

The Proceedings of Hydro ’96 yield many good papers.

29 Seminars/Conferences/Events

Conferences in the US, the UK, Malayasia and New Zealand; and a “Call for Papers” forWODCON XV and ConSoil in 1998.


CO N T E N T S


2

EDITORIAL

As new markets open up in the third world and global trade relations arestrengthened, this is also reflected in the expansion of the international dredgingmarket.

For instance, the recent maritime trade exhibition in Vietnam was enhancedgreatly by the allure of the 2nd Asian and Australian Ports and Harbours Confer-ence, sponsored by the Eastern Dredging Association (EADA), the CentralDredging Association (CEDA) and the International Association of DredgingCompanies (IADC), which ran simultaneously (page 15). The increased atten-dance at the trade show in Ho Chi Minh City was certainly related to the largenumber of participants at the dredging conference. Many fine papers werepresented, some of which may be published at a later date in Terra et Aqua.

Also the decision of the IADC to bring its one-week International Seminar onDredging and Reclamation to Buenos Aires, Argentina, indicates the recognitionof the importance of port and harbour developments in South America.

And lastly, the demand for Dredging for Development (page 14), a book jointlypublished by the IADC/IAPH, which led to its re-issuance this spring in a revised,updated edition, suggests that the interest in dredging in developing countriescontinues to be on the rise.

Marsha CohenEditor

Seaward Coastal Defence Scheme Eierland

3

D. Rakhorst, D. de Wilde and C. Schot

Seaward Coastal DefenceScheme Eierland

Abstract

As early as the 12th and 13th centuries, the unitedsand barrier in the north of The Netherlands, dividedinto the separate islands such as Texel and Vlielandknown as the Wadden Isles. The coast of Eierland inthe NW corner of the Isle of Texel has been eroding formore than a century, and since 1979 this has beensubject to sand replenishment.

The objective of the Netherlands Ministry of Transport,Public Works and Water Management (RijkswaterstaatRWS) was to construct a coastal defence scheme as ameans to prevent coastal erosion. After determiningthe cause of coastal erosion, three possible solutionswere considered: breakwaters, beachheads and dams.

Considering morphological, ecological and economicaleffects, it was decided to construct a dam. Variousalternatives for the dam were considered and a selec-tion was made based on durability, cost and feasibility.Despite difficult weather conditions the construction iscompleted and appears to be meeting expectations tocurtail erosion.

Introduction: Case History

The coast of Eierland in the NW corner of the Isle ofTexel has been declining for more than a century (Figures 1 and 2). A yearly loss of a million cubic metresof sand is recorded. Since 1979 this has been compen-sated by sand replenishment to date, this ± 5 kmregion has received nearly 10 million cubic metres ofsand. Politically seen, replenishment is in line with thepresent Dutch national policy regarding coastal protec-tion (1990), which has opted to maintain the presentcoastline. In taking this approach one has to conclude that inplaces with extremely heavy erosion, the option of aseaward approach might be more effective. The Ministry of Transportation, Public Works and WaterManagement has therefore requested research intothis matter; not only on the effects regarding the coast,but also as it effects landscape, ecology and tourism.

Mr Rakhorst is employed by theMinistry of Transport, Public Worksand Water Management, DirectorateGeneral North Holland, as a seniorpolicymaker for coastal zones. For theEierland project he chaired the work-ing group Morphology and hadoverall responsibility for the design of the works.

Mr de Wilde is also employed by theMinistry of Transport, Public Worksand Water Management, the CivilEngineering Division. He is a special-ist in the field of project design,execution and process management,and initiated the quality managementsystem as it was applied in the Eier-land dam project.

D. Rakhorst

D. de Wilde

Mr Schot graduated from the Zeeuws Technical Institute, The Netherlands and joined HAM in 1963 where he has fulfilled a variety of positions. He is presentlyRegional Manager for several coastalzones of The Netherlands, includingthe Isle of Texel.

C. Schot

The first designs of a seaward defence of Eierland datefrom 1975. Also the policy-analytical research of thecoastal protection of Texel, the so-called SIBAS-study(1982), refers to the possibility of a dam at Eierland.This only appeared to be more advantageous at a sand price for beach replenishment of about NLG 7 per m3.

COASTAL EROSION

The Wadden Isles in the north of The Netherlandswere originally a united sandy barrier. As a result ofstorms in the 12th and 13th century a channel originated between the islands Texel and Vlieland. Also Eierland became a separate island; the construc-tion of a driftsand dam in 1630 reunited it with Texelagain (Figure 3). In time a sandy area formed in front of this dike whichis presently known as the Slufter area. Because of thisbarrier, the flow rate in the Eierlandse Gat increased,the Head of Eierland eroded and the Vliehorstincreased in strength. From 1700 to the beginning ofthe 20th century there was a balance in the situationaround Eierland, even though there was an enormouscoastal increase between 1850 and 1880.

Since 1880 the coast of Eierland has been eroding,presently at about 6 to 8 metres a year. The mostimportant reason for the erosion is the tidal currentsbetween Texel and Vlieland. At high tide the waterflows in along the top of Texel and carries the sandaway from the coast of Eierland. At low tide the waterflows out through a channel, the Engelsmangat, cen-trally located between Texel and Vlieland, to an outerdelta offshore the coast of Vlieland. Eventually wavescarry this sand to the coast of Vlieland.


4

Oude Schild

Robbe

gat

Proje

ct s

ite

Eierlandsegat

Engelsmansgat

Figure 1. (Left) Lap of the Netherlands with the Isle of Texel.

Figure 2. (Above) Detail of the Isle of Texel with names ofareas as they appear in the article.

Figure 3. The coast of Eierland has been eroding for more thana century; shown here erosion between 1860 and 1990.

The Slufter

4. Beachhead series consisting of:550 m dam at km 30.5300 m dam at km 29.5250 m dam at km 28.5200 m dam at km 27.5

All financially attractive solutions require the initialconstruction of the 550 or 600 m dam at km 30.5.From a financial viewpoint, all measures are equallyexpensive, only the 1500 m dam was considerablymore costly. These four solutions as well as sandreplenishment have been considered in the Environ-mental Impact Study [EIS].

EIS RESULTS

Research was done on the effects: - morphological, - ecological, and - economical.

Morphological effectsThe current around the head of Eierland has a tidalinfluence. With a dam or beachhead, at windward sidesedimentation will occur, while the lee side will erode.To what degree this will occur will be determined bythe length and location of the dam. A dam at km 30.5will have hardly any lee side erosion, compared to a

POSSIBLE MEASURES

Having established the cause of the coastal erosion,the search for solutions began (Figures 4 and 5). Afterthe first wide-range selection, the following optionswere selected: – breakwaters (dams parallel to the coast), – beachheads (short dams perpendicular to the coast),

and – dams.

These options were studied by the Delft HydraulicLaboratory with 1- and 2-dimensional models (flow,wave and sand transportation models). With thesemodels the shoreline’s geographical position in timewas determined as well as the areas which would beaffected by sedimentation or erosion. Also determinedwas the amount of sand needed for replenishmentmeasures. The studies showed that breakwaters didnot outperform beachheads, and since they are moreexpensive, they were eliminated.

Further studies were done on beachheads and 1 or 2long dams, whereby location and length were varied.Besides just sand replenishment four other “hard”solutions were considered. These four were:1. 1500 m dam at km 30.52. 600 m dam at km 30.53. 600 m dam at km 30.5 and 800 m dam at km 29.5


5

Figure 4. Combined dam solutions 2 and 4 at the head ofEierland, as explained in the text below.

Figure 5. Combined dam solutions 1 and 3 at the head ofEierland, as explained in the text below.

dam at km 29.5. The sedimentation at the windwardside will be considerably less by a dam at km 30.5 thanat km 29.5. This is caused by the strong coastal curving at km 30.5.In all solutions the sedimentation is rather sluggish andwill have to be (at least temporarily) supplemented.There need not be any concern about the sedimenta-tion of the Slufter mouth. An erosion hole will appear infront of the dam. Since there will be hardly any changein the discharge of the Eierland sea outlet, the presentbalance of the inner delta will be maintained. However,several changes in the outer delta may occur, especial-ly if the dam is longer and closer to the Head of Texel.Since the sand supply will be partially stopped, one canassume that the sedimentation of the NW sector of theinner delta will diminish or even stop (Figure 6).

Ecological effectsNone of the measures will cause serious ecologicalchanges in the inner or outer delta. The shoals andchannel areas will remain the same. Also the Slufterarea will barely be influenced. The main change will bethe creation of a foreshore. A small dam will yield asmall foreshore, a large (lengthy) dam will supply alarge one. The existence of a foreshore will, however,raise the groundwater level in the nearby dunes. The result being a wetter dune area and possibly dunelakes will appear (Figures 7 and 8).

However, judgements about this are debatable. The study group ”Ecology“, which is involved in thismatter, consider dune lakes to be a negative aspect,since they attract seagulls, whose droppings will createeutrophication. Except for the 1500 m long dam thesolutions are acceptable. All solutions will change thelandscape. Also in this respect, the larger the dam orforeshore, the more change in landscape.

Economical effectsNone of the solutions will have a significant effect inregard to recreation or economy. It should be borne inmind that no recreational or agricultural activities shouldbe developed on this newly formed foreshore.

THE SOLUTION

The 1500 metre dam was dismissed because of itshigh cost and possible negative morphological andhydrological effects. The choice fell ultimately on the550 m dam with replenishing of 2.0*106 m3 sandduring the construction of the dam, 1.6*106 m3 after 5 years, 1.1*106 m3 after 10 years and afterwards0.6*106 m3 every 5 years. By constructing the 550 mdam with beach replenishment, one has chosen for oneof the less expensive solutions and also one with theleast amount of morphological and ecological changes.If, however, this proves unsatisfactory after all, a furtherseaward approach constructing a 800 m dam at km29.5 or opting for series of beachheads is possible.

THE DESIGN

Morphological interventionIn the first instance the plan consisted of constructionof the dam and the placing of 2*106 m3 of sand, the latter replenishment borrowed further offshore atbelow the NAP (New Amsterdam Level) -20 m-line.However to spread the costs over a two-year periodthe replenishment was split up in 1.3*106 m3 placed in1994 and the remaining 0.7*106 m3 in 1995 when thedam was built. Mid 1994 the idea of a morphologicalintervention arose (Figure 9). The intervention consistedof digging a flow channel between the erosion holewhich would develop between the head of the damand the Robbengat. This plan served three purposes:

1. The channel would cause sand to be deposited atebb tide in the outer delta offshore Eierland. Thewaves then carry the sand to the shore of Eierland,therefore requiring less replenishment in the future.At ebb tide right now, most of the sand is depositedthrough the Engelsmangat and a lesser amountthrough several smaller ebb channels which developed a more westerly orientation in the outerdelta. The new ebb-flood channel could take on thetask of the existing smaller channels.


6

TEXEL

N

VLIELAND

increasing depthsdecreasing depths

0.50

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.50

Figure 6. Sea bottom changes in metres as a result of a 1200-metre-long dam, according to a Delft Hydraulic LaboratorySCOUR model.

port gradations will diminish. The chances of chan-nel-forming will decrease. At the same time part ofthe dam can be made of a somewhat lighter con-struction, and the chances of damage will diminish.There is an analogy with the construction and exten-sion of the harbour breakwater at Amsterdam’souter port IJmuiden. The largest sedimentation wasthere, where sand was placed in the neck.

Longitudinal profile of the damStarting point was a dam length of 550 m, from themost seaward MLW-line. Up to the foot of the dunethe total length of the dam will then be 800 m.

2. The sand released by the construction of the channelcan then be used for the remaining replenishment of0.7*106 m3. Because of the shorter delivery distance,this sand will be cheaper than when having to beborrowed below the NAP -20-line.

3. Some experts are worried about channel-formingalong the south side of the dam. This can possiblyoccur during a southwestern storm, during whichthe water will be driven along the south side of thedam. By depositing 300,000 m3 of sand in the neckof the dam, the current will be brought offshore andthe current gradations and therefore also the trans-


7

Fresh water reservoir

New groundwater level

Figure 7. Groundwater level in the present situation. Figure 8. Groundwater level rise in a situation altered bycoastal accretion.

Figure 9. Drawing with chosen solution and morphological intervention.


8

Figure 10. Top view and longitudinal profile of the dam.

Figure 11. Cross-sections indicated in Figure 10 are shown here: 1) at the head; 2) in the middle section; and 3) at the beach.

Cross - section 1

Cross - section 2

Cross - section 3

After a first selection, 6 varieties remained for furtherconsideration:- rockfill, homogenous;- rockfill, with core;- bitumen penetrated stone, saturated;- bitumen penetrated stone, pattern penetrated;- sand pancakes; and- pile planking.

The last three were deleted because of, respectively, a lack of construction experience, cost, and uncertaintyin regard to life expectancy.

The dam can be divided into three parts, based ondesign and construction aspects:- beach: always dry construction;- body: sandtrapping; and- head: stability point in surf zone.

Therefore the following constructions have been chosen:- beach: sand body covered by rock fill penetrated with

asphalt, in order to obtain a strong and inex-pensive cross-section;

- body: rockfill with core, because of tight and cheapconstruction; and

- head: one type of rock fill, because of solidity andthe lesser importance of sand tightness.

Figure 11 shows three cross-sections: one is a cross-section at the head; two is a cross-section in the mid-dle; and three is at the beach end.

An erosion hole at NAP -10 m will form at the head of the dam. This expectation is based on the flow rate pulling along the dam and on the analogy of the IJmuiden breakwaters. However the same conclusion was reached in themodel research.

Calculating the realistic slopes of the underwater sea-shore, an approximate 300 m seaward displacement ofthe MLW-line was found. Accordingly a shore inclina-tion of 1:100 needs a foreshore of approx. 250 m atNAP +1.5 m. In this section the dam will be at a heightof about 0.5 m above foreshore level, to assure that thesand will be retained. This height is further necessaryto keep the water from flowing across the dam. (About once a year NAP +2 m will be surpassed.) The head of the dam will be at NAP +0.5 m. This damheight was established mainly because of the demandto make the dam passable most of the time. At thesame time eventual sand transport across the dam isnegligible. The height incline of the dam is gradual,from NAP +2 m to NAP +0.5 m (see Figure 10).

Cross-sectionMany alternatives were generated for the constructionof the dam. These alternatives were: - free dumped rockfill (4 varieties); - penetrated rockfill (4 varieties); - concrete elements (3 varieties); - solid construction (3 varieties); and - sand construction (4 varieties).


9

Figure 12. Work in progress at the Eierland dam as at May 1995.

THE CONSTRUCTION

The beach replenishment in 1994 has been executedby a contractors joint venture, consisting of HAM-Van Oord Werkendam bv, Boskalis Oosterwijk bv andD. Blankevoort bv. The project of the dam was tenderedon 16-12-1994 and awarded to the contractors jointventure; HAM-Van Oord Werkendam bv., P. DaaldersContracting Company bv and Van Oord-ACZ bv. The construction was completed on 01-10-1995 (Figure 12).

Special circumstances during execution of the worksThe NW coast of the Isle of Texel is a difficult area towork in, mainly because of weather conditions:- The navigation route from the Waddenzee changes

constantly. Therefore it was necessary to make daily reconnaissance trips along the route due towandering shallowness.

- The dam has been projected in an area with waterdepths varying from NAP -4.50 m to NAP +1.00 m.The average high water is at NAP +0.60 m, the average low water is at NAP -0.80 m.

- The toleration requirement of +/- 10 cm to ensure alevel top layer with 1-3 tons stones is physicallyimpossible.

PreparationsBefore starting the actual construction, 3 stone depo-sits were established at the head of Eierland. The rockfill, originating from Norway, was delivered byship. About 90,000 tons were delivered in Oudeschildand stored in depots; 27,000 tons were depositedstraight from the barges onto the site. Simultaneously two mattresses were constructed onthe parking lot next to the lighthouse, to enable con-tinuous sinking operation. From there the mattresseswere pulled to the shoreline by mechanical shovels andsubsequently towed to the sinking site. At the start ofthe project sinking of the mattresses was much delay-ed by the constant swell. Later the delay was made upwhen it became possible to sink 3 mattresses per day.The execution of the beach part of the dam could onlybe done after the beach was heightened by sandreplenishment. At the start of the construction thebeach had decreased to such extent that it was impos-sible to gain access with the construction equipment.

Beach replenishmentIn 1994 already 1.3*106 m3 of the replenishment of2.0*106 m3 had been placed. This sand was reclaimedby trailing suction hopper dredgers from a borrow areaoff the centre of Texel below the NAP -20 m line. In 1995 the remaining 0.7*106 m3 of the replenish-ment was placed and another 0.3 million cubic metresin the neck of the dam. The latter 1 million cubicmetres has been placed in seven days and has alsobeen used to make the beach passable for constructionequipment. This was borrowed by the cutter suctiondredger Sliedrecht 34 from an area between the futurescour hole at the head of the dam and the Robbengat.In reality 100,000 cubic metres of extra sand wasplaced free of charge, as a result of the less expensiveway of execution (Figure 13).

Dam with sand core Figures 14 and 15 show the site during the executionperiod. This part of the dam with a length of 275 m hasbeen executed by excavating the (heightened) beach. On the excavated sand profile a polypropylene filtercloth with reed cover has been placed topped by alayer of stone 10-60 kg. An asphalt mixture has beenpoured over and in between the stones. The bermshave been finished off with stone 60-300 kg.

Dam with core of rockfill Originally the core would consist of phosphor slag’scovered by stone 10-60 kg. At the request of the contractor this was changed to a core of only stone 10-60 kg. The core of the first 400 m of this part of thedam was delivered by driving over the dam. The crestof the core was temporarily filled with stone 60-300 kg,to create enough work space to be able to use ahydraulic excavator over the first 400 metres, to placethe 1-3 tons stone cover layer in the crest. The work was done seawards to land side and moving


10

Figure 13. Cutter suction dredger Sliedrecht 34 was used forbeach replenishment at the start of the construction.

Figure 14. Close up of stone dumping on the dam.

ing method, but can be done with the help of stonedumpers.

- Extra equipment is required because of the com-bined “dry “ and “wet” working methods.

- The best working method is to extend as much aspossible the “dry” construction from the beach.More security is given by constructing the dam in acompletely “dry” way.

- When confronted by similar work at depths of lessthan 3 metres, the dry method should certainly bechosen to avoid the risks due to weather, waves,swell and so on.

- Driving across rockfill 1-3 tons is impossible withouta fill-in layer.

- The location to assemble the mattresses was fixedin the specifications. At this location it proved difficultto couple the tow beam of the mattress at high tide.

- A floating crane with stone pontoon alongside isoverly sensitive to swell.

- The specification quantities were calculated, bytheoretical means, in cubic metres. By conversion ofcubic metres to tonnes, one should not calculate byvolume weight (mass 2800 kg/m3 x 60% = 1680kg/m3). Practice has proven that, including deviationsof mass, deviations in void percentages, losses and freeboard, a bulk specific gravity of about 2000 kg/m3 should be calculated.

QUALITY GUARANTEE

The construction of the Eierland dam occurred under aquality guarantee. It was one of the first “marine”

backward the 60-300 kg stone were picked up andplaced onto the berm. The cover layer of the mostseaward section, with a length of 150 m, was placedwith the aid of a floating crane, seagoing barges andstone dumping vessel HAM 602.

Head of the damThe body of the head of the dam is completely con-structed from rock 3-6 tons. The berm has, as is thecase along the total dam, a cover layer of rock 1-3 tonsover a 3 m width. This construction was a marineoperation insofar as the navigable depth allowed. The section of bottom protection, outside the coverlayer of stone 1-3 tons is covered with stone 60-300 kg.This stone was placed with a stone dumping vessel, atlower depths with seagoing barges and floating cranes,and, at depths of NAP -1.00 m. and higher, with hydrau-lic excavator and dumpers. The dam was finishedbefore October 1st 1995. Until now the dam has heldits profile very well.

Some conclusions about construction methods- The weather influx was underestimated (wind force

4 nationally in The Netherlands is wind force 6 at theIsle of Texel).

- The supply capacity of the heavy rock and the prog-ress of the bottom protection work define the prog-ress of construction.

- The transportation of rock on stone pontoons, fromOudeschild across the North Sea is an unsafe work-


11

Figure 15. Overview of the Eierland dam as it nearscompletion.

construction projects commissioned by the client TheNetherlands Ministry of Transport, Public Works andWater Management (Rijkswaterstaat RWS) DirectorateNorth Holland done under quality guarantee. The mostimportant considerations in applying the quality guaran-tee were:- Future RWS policy in relationship to contracting

certified contractors.- Gaining experience in this type of working method in

order to learn and apply this to own organisation andfuture projects (Pilot Project).

- It was possible to appeal to the Bouwdienst RWS(Construction Service RWS), which had experiencein working with quality guarantee, so that they couldbe counted on for support during the tender, awardand construction phases.

- To put the responsibility during the constructionwhere it belongs, namely, with the contractor.

The purpose of quality guaranteeSocial relations have changed and equality between theparties entails working together, each in the realm ofthe specific tasks, although each party ultimately has itsown interests.The modern working method entails,client and contractor, each with their own tasks,responsibilities and qualifications. In construction atendency toward product liability continues, therebyrequiring the producers to be more and more responsi-ble to deliver quality goods. Accepting product responsibility goes hand in handwith the competency to make one’s own decisions.The traditional work method in which the supervisordetermines the quality, does not fit into this philosophy.Quality guarantee means that the contractor mustshow the products made meet the requirementsagreed upon in the tender specifications. In this waythe party which can influence the processes most is incharge of the quality. The client’s role shifts to one ofauditing the work, through which he becomes respon-sible for eventually proven faults in construction.

Working methodIn the preparatory phase much emphasis has been putinto drawing up the product-oriented tender specifica-tions, including quality assurance aspects, and into theeducation of the project employees. Prior to the start of the project, the quality controlsystem handed in by the contractor has, by means ofNEN ISO 9002-norm, been commented on and eventu-ally been accepted. By means of the contractor’s technical evaluation plan,based on the critical parts, properties of constructionand processes, the execution and inspection planpresented by the contractors has been judged, discus-sed and accepted. Various construction processes andmeasuring methods were described in the executionplan, while executed measurements and controls, to be executed per subproduct were described in theinspection plan. Also the attendance, report and stop

items, requested by the client were described. These items were meant to give the client the opportu-nity to be present at the inspections and measure-ments or do them itself. In addition, the client madeseveral system and product audits to ascertain that thecontractors adhered to the procedures and workingmethods as described in the plans.

Findings about quality guaranteeThe project’s most important findings in regard toworking under quality guarantee, as experienced by theclient are:- Communication between client and contractor is of

utmost importance to guarantee a final quality plan.- At the start of the project “double work” occurred

during a certain period, because the client’s side”held on” to the existing security. Only after thecontractor proved to be able to hold his own securitydid more trust developed.

- Uncertainty existed on the part of the auditors as towhen they could intervene in the contractor’s pro-cess. The traditional type of supervision to whichthey were accustomed, and working with qualitycontrol demanded a subtle combination. Therefore,on the one hand all project employees need to haveenough know-how about and ability to deal withquality control. On the other hand the client alsoneeds to follow its own quality system in which thequalifications, procedures and working methods aredetermined.

- The project quality system was based on the certi-fied system of one of the contractors and imposed,more or less via a “top down” system, on all projectemployees. This led to a bit of a problematic start.

- In case of increased pressure on cost and planning,quality control is easily dropped.

- Audits implemented by the client are an importantmeans to measure the quality control. The auditshad a positive influence on the quality awareness ofthe employees of both parties.

COSTS

The total project exists of the construction of a ± 800metres dam at km 30.5 and of a sand replenishment of2.0*106 m3. Included in the cost of the dam is the sandreplenishment of 300,000 m3 in the neck of the dam.There is no cost involved for the excavation of the ebbchannel of the cutter dredge at the head of the damand the Robbengat since this was part of the sandborrow area.

Scope of the worksAccording to the tender documents the scope of theworks was as follows:- beach replenishment 300,000 m3

- rock; all types 95,800 tonnes- mattresses 24,000 m2


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- a much deeper scour hole (up to NAP -18 m) thanexpected. This led to placement of an extra rubblelayer, after the completion of the dam, and again atthe end of 1996. Expectations were for a muchwider and more shallow hole. Possibly because ofthe position in the outer delta which causes sandpressure, a smaller and deeper hole was formed;

- sedimentation on the south side of the dam. Closeto the dam the MLG-line has moved more seawardthan expected. As the coastal curve is too sharp, thisled initially to a disappointing amount of sedimen-tation;

- the dredged ebb channel indeed did place a largequantity of sand at the coastline of Eierland. UntilNovember 1996, this sand was not mobile becauseof the lack of storms. As expected, however, afterthe November/early December storms a fair part ofthe sand has moved to shore. Because of thestorms, the shoal north of the dam has been re-duced in height and the sand has moved to theedges of the shoal. After the storms the scour holehas been reduced with 1.5 m;

- the dredged ebb channel has not silted but unfortu-nately has moved in the same manner as the originalsmall ebb channels. The expectation is that this dis-placement will continue and that the ebb channel willeventually be extinguished. Unfortunately this meansthat in time much less sand will be carried through theebb channel to the NW part of the outer delta.

Up to now the main purpose of the dam has met theoriginal objective, which was to limit the erosion of thecoastal plain of Eierland. If, as expected, a replenish-ment of ± 1.5*106 m3 is necessary in 1999 remains tobe seen.

In 1992 it was estimated that, if the work was done in1994, the total cost of the project would be ± NLG. 30million. Total project cost, including VAT were as fol-lows:– dam: NLG 16.0 million– beach replenishment: NLG 21.0 million– Total: NLG 37.0 million

For this amount more than 100,000 m3 extra sand hasbeen placed.

Conclusions

Regarding the morphological evaluation, the expecteddevelopments were:- sedimentation on the south side of the dam;- the forming of an erosion hole with a depth of

± NAP -10 m at the head of the dam;- sedimentation offshore Eierland resulting from the

digging of the ebb channel;- light sedimentation of the Robbengat and erosion in

the Engelsmangat caused by altered flow rates, but also lee side erosion in the Robbengat;

- displacement of the ebb channel in NW direction.

Actual morphological developments are (Figure 16):- major, unexpected sedimentation on the north side

of the dam. The total area between the dam and thehead of Eierland is sedimented with nearly 1 millioncubic metres of sand;

- major erosion in the Robbengat;


13

30

30

30

30

30

01

21

41

61

81

+2

+2+3

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+1

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+1

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0

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0

0

0

0

0

0

0

0

0

Figure 16. Sea bottom changes in metres as at December1996.

Dredging forDevelopment(Fourth Edition)

Continuing its policy to support educational programmes,the IADC is happy to present a newly revised andupdated fourth edition of IAPH’s introduction to thecomplexity of dredging. Although particularly directedto an audience in developing countries, the book is alsoan excellent introduction for legislators, regulators andthe public-at-large in developed countries.

Since its first appearance in 1983, the book has been inconstant demand and has undergone several revisionsto keep pace with new developments, first in 1987 and then again in 1991. Retaining the non-technicallanguage of former editions, this fourth edition remainsan excellent primer on port development, with specialemphasis on capital and maintentance dredgingaspects. It takes into account issues and technologicaldevelopments of the last four years, and additionalattention has been given to environmental dredging.

Chapter One discusses the nature, need and impor-tance of dredging. The basic objectives of dredging areexplained including: navigation, flood control, construc-tion and reclamation, mining, beach nourishment, andenvironmental remediation. The types of material generally dredged are listed andcharacterised, and an overview of the dredging industryis presented.

Chapter Two highlights the process of port develop-ment and dredging. Issues such as planning, design,financing and construction of port projects, includingthe process of tenders and bidding are described. The execution or construction as well as operation andmaintenance of completed projects are also discussed.

Chapter Three elaborates on the usual contract provi-sions involved in tenders and bidding, such as bills ofquantity, rates, unit cost or lumpsum, and alternativetenders. A section on “conditions of contract” empha-sises important issues such as risk allocation, the rolesof engineer and supervisor, soil conditions, and insur-ance to name a few. The need for inspection andmeasurement of operations, and permits for dredgingoperations are explained.

In Chapter Four types of equipment employed andfactors affecting the choice of equipment are alsodiscussed at length. A good description of varioustypes of dredgers, embellished with a wealth of illustra-tions, helps the reader understand the techniques ofdredging and which dredger is suitable for which activi-ty. The transport and placement of dredged material isanother integral part of the process which is clearlyexplained and the need to consider this early on in aproject is emphasised.

In this new edition, environmental factors related todredging receive increased attention. Both ChaptersFive and Six delve into the environmental aspects of dredging, discussing the variety of impacts, water,


14

EDITED BY CHARLES W. HUMMER, JR.

INTERNATIONAL ASSOCIATION OFDREDGING COMPANIES

THE INTERNATIONAL ASSOCIATION OFPORTS AND HARBORS

F O R D E V E L O P M E N TD R E D G I N G

Fourth EditionMarch 1997

A joint publicationof IADC and IAPH

Charles W. Hummer, Jr.Editor

numbers. And Appendix B includes an extensive refer-ence list of books, reports and monographs. Alsoincluded is a complete index of articles published inTerra et Aqua, as well as abstracts of articles which areparticularly pertinent to the subject of the book.

Combining the same clear, concise language of earliereditions with recent, information, this new edition ofDredging for Development offers an extremely useful,updated reference source for officials and managersresponsible for port projects.

Available free of charge from the International Association of Dredging Companies, Duinweg 21, 2585 JV The Hague, The Netherlands, tel. +31 70 352 3334, fax +31 70 351 2654.

air and land, as well as socio-economic. Again theplacement or relocation of dredged materials is viewedas an essential environmental consideration and recei-ves special attention.

Chapter Seven expands the information on the role ofthe World Bank in the development of ports and har-bours. When considering applying for financial supportfrom the Bank and its affiliates, port authorities need tobe aware of its policies and long term strategies. Reor-ganisation, management, and environmental issues aretop priorities and are described in this closing chapter.

In addition, Appendix A provides a comprehensive listof pertinent international organisations and develop-ment banks, with contact addresses and telephone

Dredging for Development (Fourth Edition)

15

With the dramatic economic growth occurring inAsia and the opening up of Vietnam to world mar-kets, the Eastern Dredging Association (EADA)decided to hold its second regional conference inHo Chi Minh City in association with the tradeexhibitiion Maritime Vietnam '97. This secondEADA conference was co-organised by the CentralDredging Association (CEDA), the InternationalAssociation of Dredging Companies (IADC) and theVietnam National Maritime Bureau (Vinamarine).

The three-day conference featured a full programmeduring which some 35 papers were presented. The subjects of papers covered a broad area ofexpertise within the theme "Developing and Main-taining Operational Ports and Harbours into the 21stCentury". These included discussions of the devel-opment and opportunities for dredging, reclamation,and port construction in Vietnam, Indonesia,Malaysia and Singapore, as well as the privatisationof ports in Asia and elsewhere.

Other papers addressed the technology of dredgingwith subjects such as the design of revetments;the application of fluorescent artificial sand and silttracers; studies of siltation, and hydraulic and sedi-mentological surveys at the Port of Hai Phong;environmental modelling in a tropical environment,as well as up-to-date reports on environmentaldredgers such as the auger suction dredger.

On the fourth and final day a boat trip on the SaigonRiver provided a suitable close to the conference,and gave attendees the opportunity to see the portdevelopments of the host city in action.

The complete Proceedings of the conference are being published this summer by the IADC, in cooperation with EADA and CEDA, and areavailable for US$70. To order please contact theIADC for further information.

2nd Asian and Australasian Ports and Harbours ConferenceApril 16-18, 1997

Ho Chi Minh City, Vietnam

The IADC booth at the trade exhibition Maritime Vietnam '97, held in the Ho Chi Minh City ConferenceCentre. Some 130 companies from 18 different countriesparticipated.

Harald F. Köthe

Management of DredgedMaterial in Germany; A Compromise betweenEconomy and Ecology

Abstract

Each year in Germany construction and maintenance ofwaterways produce considerable volumes of dredgedmaterial, which may contain varying amounts of con-taminants. New priorities of waste and environmentalpolicies entail considerable consequences for thehandling of contaminated dredged material, since it isnow mandatory to consider ecologically and economi-cally reasonable uses before opting for upland or aqua-tic disposal. Guidelines for the dumping or relocation of dredgedmaterial in waters have to be developed. A professionalapproach to dredged material management is requiredto work out a time-saving and cost-efficient solution -- a compromise between economy and ecology -- tailored to the specific circumstances of each project.

Introduction

Maintenance or capital dredging works on water bodiesin Germany fall either under the responsibility of theFederal Administration, or the designated authorities ofthe 16 Federal States (LAENDER) or 16,099 municipali-ties (structured in 416 districts, 15,982 communities,117 communities without district affiliation; DEUT-SCHER STAEDTETAG, 1993) with overlapping occur-ring (see Figure 1). The Federal Ministry of Transportand its subordinated authorities are responsible for theFederal coastal and inland waterways (with a totallength of 7700 km).

Dependent on the type of project, dredged materialmay consist of- sediments or subaquatic soils of the water bottom;- subsoils and their parent material from the immedi-

ate vicinity of the river bed, or- top soil from the banks or the floodplains of the river

(DIN 19731).

The fresh sediments on the river bottom usually makeup only a small portion of the removed material incapital dredging, while they predominate in mainte-nance operations. A nationwide inventory of volumes of dredged materialand its contamination has not yet been made in Germany. Studies to acquire more knowledge andexperiences from all 16 LAENDER about the real dimen-sion of the volumes dredged in Germany are planned.

Maintenance worksThe total volume of material dredged from mainte-nance works on Federal Waterways (inland and coastalwaters) can be estimated around some 50 million m3

each year or more, with merely 1-3 million m3 originat-ing from inland waterways upstream of the tidal reach.Consequently, most of the total volume being dredgedannually stems from coastal waters. Although thismaterial is mostly sandy and clean or only very slightlycontaminated, the general image of dredged material is


16

Mr Köthe graduated in 1988 from theUniversity of Bonn, Germany with adegree in geology. He is presentlyemployed at the Bundesanstalt fürGewässerkunde (Federal Institute ofHydrology), Koblenz, Germany,where he is responsible for themanagement of dredged materialsfrom federal waterways and thedevelopment of national and interna-tional guidelines about dredged mate-rials.

Management of Dredged Material in Germany

17

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very negative. This negative image is dominated byhigher contaminated fine-grained sediments, whichoccur mostly inland more or less close to the sourcesof pollution. This problem is well known from manyother countries too (Vellinga, 1995; PIANC, 1996).

The volumes of potentially fine-grained material fromannual maintenance dredgings in all German inlandwaters (Federal Waterways and LAENDER waters) canbe estimated very roughly at about 5-10 million m3.About three million m3 of this amount is being dredgedannually in the LAENDER harbours of Hamburg andBremen (Koethe, 1995a) (Figure 2).

Construction worksAdditionally, the dredged volumes from water con-struction projects have to be regarded. The currentplanning of the Federal Ministry of Transport for in-stance provides for 29 major projects to adjust water-ways to the larger, more efficient and competitive

barges of today (WaStrAbG, [E. 1995]). Experienceshows that the total volume dredged during a capitaldredging project ranges mostly between 100,000 m3

and 10,000,000 m3. Although usually only 1 to 10% ofthe huges masses moved in these capital dredgingprojects are contaminated, this portion may cause greatproblems in disposal and beneficial use, especially inlarger projects (Figure 3).

It is obvious that construction and maintenance workon waterways in Germany each year produce consid-erable volumes of dredged material, which may containvarying amounts of contaminants. The handling ofdredged material has increasingly become a problem,last but not least because dumping or relocation inwaters is becoming more and more restricted withregard to the protection of the environment. Moreover there is a general shortage of upland disposalor dumping capacities in Germany, which may causeproblems even for the disposal of clean dredgedmaterial. A professional dredged material managementscheme is needed to coordinate all the differentrequirements to run a dredging project successfully.

CONSEQUENCES OF WASTE AND

ENVIRONMENTAL POLICIES FOR DREDGED

MATERIAL HANDLING

Every dredging project has to deal with the decision,whether the dredged material has to be classified aswaste. Owing to the lack of specific laws or nationwideregulations for handling dredged material, the new “Acton Waste Management and Recycling” (Kreislaufwirt-schafts- und Abfallgesetz, KrW-/AbfG 1994), which willcome into force in October 1996, has to answer thesequestions. Pursuant to §3 KrW-/AbfG the “will to dis-pose of” (in the sense of throwing away) is the decisivecriterion for the classification of a substance as waste.


18

Figure 2. Old ”workhorse” WD Gateway doing maintenancedredging in Hamburg.

Figure 3. The new “jumbo” TSHD Amsterdam pumping her first load of sand ashore for the reclamation of the Europa quay at acontainer terminal in Hamburg. The sand was dredged from the North Sea, 120 km away.

Avoidance (AbfG, KrW-/AbfG)

Relocationin Federal Waterways

(WaStrG)

Waste Disposal

Beneficial Useafter pretreatment, treatment

upland(AbfG, KrW-/AbfG)

subaquatic(WHG)

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WaterwaysDumping/

Incineration

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Beneficial Use(AbfG, KrW-/AbfG:

no waste)

simplified legislative scheme for dredging projects onfederal waterways. It gives an overview which lawsapply dependent upon the handling of the dredgedmaterial (HABAB, draft 1996).

As mentioned before, most of the material dredged inGermany is clean or only slightly contaminated. There is no doubt, relocation of the dredged material inthe water is the most cost-efficient way to handle thematerial. Consequently, there is a need to define criteria for the relocation of dredged material in water,which has not yet been done in any nationwide regula-tion. To date there is neither a specific law to governthe handling of dredged material nor nationwide criteriafor the relocation of dredged material in the water inGermany.

The Federal Ministry of Environment and the 16 LAEN-DER-Ministries of Environment are responsible for the

Thus, if dredged material is abandoned without anyfurther beneficial use, it has to be classified as “waste”irrespective of its contamination (§3 KrW-/AbfG). “Waste” that is beneficially used, is “usable waste”and “waste” that is disposed of is “disposable waste”(§4 KrW-/AbfG). §4 KrW-/AbfG sets the following priori-ty if this notion of “waste” is applied to dredged mate-rial:1st: Avoidance2nd: Beneficial use3rd: Dumping

These new priorities entail considerable consequencesfor the handling of contaminated dredged material,since it is now mandatory to consider ecologically andeconomically reasonable uses before opting for uplanddisposal or dumping. This makes the application oftreatment technologies to remove or isolate the con-taminants more and more necessary. Figure 4 is a


19

Figure 4. Legislative framework for the management of dredged material in the Federal Republic of Germany.

Explanation of abbreviations for German laws:

AbfG – Waste ActKrW-/AbfG – Waste Recycling ActWaStrG – Federal Waterway ActWHG – Water Balance Act

protection of the environment. They have appointedexpert groups with delegates from all LAENDER andthe Federal Administration to define target values forthe water, suspended solids, and the sediments of thewaters in Germany (Schudoma, 1993).

These values are very strong and they can be under-stood as a political aim to bring back better water andsediment qualities in German waters in the future(ecological aim). To keep the present maintenance andcapital dredging work running (economical aim), it isnecessary to have a different regulation, practicallyorientated, for dredged material including criteria for therelocation of dredged material in the water. Conse-quently for the Federal Waterways two directives -- onefor coastal (HABAK-WSV, 1992) and one for inlandwaterways (HABAB-WSV, draft 1996) -- contain suchcriteria with regard to the aims of the environmentalpolicy mentioned above, but with the first priority not toallow the present environmental situation to deterio-rate. Besides this there are also activities in differentLAENDER to develop guidelines and criteria for singlerivers with regard to the special environmental andpolitical situation around this river (e.g. Arge Elbe,1996).

In this context many controversial discussions aboutenvironmentally acceptable contamination limits for therelocation in waters, about cost-participation of theproducer of the contamination, and about improvedpractices of source control have taken place and arestill going on with the intention of developing guidelinesand criteria that find nationwide acceptance.

Contrasting viewpointsTwo extreme points of view stand in contrast to eachother about how best to handle the material:a) the immediate observance of target values for waterand sediment quality intended by environmental policy.Enacting this would create very high costs for thehandling and treatment of large amounts of only slightlycontaminated dredged material, so that many mainte-nance or construction projects could not be realised.This would have severe economic consequences.b) the permission to relocate all sediments within thesame hydrological system, irrespective of the degree ofcontamination, is supported by two important argu-ments:- the contaminated sediments dredged annually

represent only a small percentage of the totalamount of contaminated suspended solids flowingdownstream every year; and

- the authorities responsible for the maintenance orconstruction of waterways are not usually the produ-cer of the pollution and to get cost-participation ofthe producers of the pollution is often very difficult orimpossible.

Though there may be truth in this argumentation, fromthe view of environmental protection policy, this ex-

treme way of acting cannot be allowed. However indeveloping policy one tries to strike a happy medium.This means that the important aims and target valuesintended by environmental policy should be adhered toin daily routine practice. Therefore, a step by stepdevelopment is needed to come closer and closer tothese aims, in order to be able to continue our dailybusiness.Consequently, a compromise between ecological aimsand economic possibilities has to be worked out andtailored to the specific circumstances of each project.Insofar the handling and treatment of dredged materialhas become a very complex affair (PIANC, 1996). Everyproject leader (maintenance or construction) in order tosave cost and time is well advised to use a professionalapproach to dredged material man0agement (DMM)from the early planning phase on.

TASKS AND BENEFITS OF A DREDGED

MATERIAL MANAGEMENT (DMM) SCHEME

As mentioned before it is difficult in many projects tofind a cost-efficient and environmentally acceptablesolution for the ultimate destination of the dredgedmaterial (DM). For projects on inland waters some-times even clean dredged material has become aproblem, especially when large volumes have to behandled. The decision whether the material can berelocated in the water, used beneficially, disposed of ortreated is dependent on the following main factors:- the volumes of DM- the degree of contamination in the DM- the physical, chemical, and biological composition of

the DM- realistic alternatives in the region - the use-dependent risks to the environment- the budget of the project owner- political movements and interest groups in the

region.

The main task of a DMM scheme is to coordinate thework on all those aspects in a time-saving and cost-efficient way and with regard to the environment. The main aspects of the tasks and the benefits of aDMM scheme are described briefly in the followingparagraphs.

A good communications plan It is not difficult to imagine that many interests mayconflict with the project plans. It is essential to establishcontact with the competent authorities, associations orinterest groups in an early stage to create an atmos-phere for open and trustful cooperation. Consequently,a very important element of the DMM scheme is agood communication plan, which will help to preventtime-consuming and cost-intensive interferencesthrough fundamental political objections in a later project phase, e.g. in plan approval procedure.


20

the decision to split the total volume of dredged mate-rial into partitial streams with different destinations. As shown below, this can be a very complex decision-making process. Only when the sum of all partitialcosts have been established can it be decided whetherthe whole project plan is cost-efficient or not.

The flowchart in Figure 5 is a simplified schemeshowing the cost-relevant handling steps of the partitialstreams. The more handling steps necessary, the morecomplex and expensive is the DMM plan (Thibodeauxet al., 1994). The only exception (which proves the rule)is the case, when the whole mass runs on a short waydirectly to a waste facility. Because of the high costsfor dumping on a waste facility it can be cost-efficientto increase the number of handling steps by usingpretreatment and treatment technologies, which allowa beneficial use afterwards instead of dumping. In thiscase the aim of the waste policy would be reachedperfectly (see above under Consequences of Waste). The general aim of the waste policy (KrW-/AbfG, 1994)is to save scarce dumping capacities by finding environ-mentally acceptable beneficial uses, with or withoutpretreatment and treatment (Figure 5). Only smallquantities of residues from pretreatment and treatmentprocesses, which are highly enriched with contami-nants (concentrates), should end up on waste facilities.

Characterisation of DMEvery DMM scheme needs a precise physical, chemi-cal and biological characterisation of the material to bedredged over the whole dredging area and depth.These data provide the basis for all following decisions. Before starting surveying and collection of data oneshould have a concrete idea about the potential desti-nation of DM including alternatives. Every investigation(in the field and in the lab) which can be combined withthe survey in this early phase will be cheaper thanstudies at a later phase of the project.

Separation of DMThe next decision to be made is whether contaminatedareas should be dredged separately. This can avoid theneed of cost-intensive separation technologies at a laterstage. The separation of clean material of differentphysical composition (e.g. gravel/sand from silt/clay)may be another interesting aspect for a further benefi-cial use (e.g. as construction material). There are manyenvironmentally acceptable, selective dredging technol-ogies available on the international market, which canbe chosen for the specific demands in each project(Palermo, 1991; Rokosch, 1993; Van Der Veen, 1993;PIANC, 1997).

If it is cost-efficient the DMM scheme should favour


21

Figure 5. Management scheme for dredged material: Cost-relevant handling steps of the partitial streams.

Flowchart 1

Relocationin waters

Directbeneficial useupland /aquatic

Transport

Transport

TreatmentPretreatmentTransport Transport

Transport

Transport

Dredging

Beneficial use / Saving landfill capacities

Beneficial use after pretreatment and/or treatment

- of clean or slightly contaminated, physically suitable dredged material

- of decontaminated dredged material

- in form of products (bricks, pellets, foamed glas ...)

chemical-physical,biological,thermal

not required in acombined plant

e.g. grain-size separationdewateringe.g. ship, truck, pipeline

selection of thesuitable technique

Dumping (upland / aquatic)on existing or new confined disposal site / landfill

Disposal without further purpose / Use of landfill capacities

Flowchart 2

yes no

Separationof problematicportions with

selectivedredging

technologies

Total volume,separated in

partitial streams

Unseparated,total volume

1 2 3 4

Relocation in waterdirect beneficial use;

upland / aquatic

Residue

(Sub)aquaticplacement / disposal

Residue

Residue

Pretreatment,treatment andbeneficial use;

upland / aquatic

Uplanddumping,

LAGA-classesZ1.1 - Z2

Upland dumping onmunicipal (Z3 - Z4)

or hazardouswaste (Z5) facilites

1.3

1.2

1.1

2.2

2.1

3.2

3.1

costs

deg

ree of co

ntam

inatio

n

Management-Pathways for Dredged Material

Physical, chemical and biological characterisation of thematerial to be dredged

Figure 6. Basic possibilities for the management of dredged material.


22

1995; Laboyrie, 1995) needs technical planning andconstruction. But again, this is less expensive thanapplying treatment technologies to the whole mass(Pathway 3, Figure 6). The cost-ranking of destinationalternatives in Figure 6 is based on the assumption thatthe residues in Pathways 1 and 2 are partital streamsdredged by selective dredging technologies. The resi-due in Pathway 3 may be a product of a pretreatmentor treatment technology too.

With regard to the Pathways 3 and 4 in Figure 6, thecentral question in the decision-process on the DMMreads: “Is the use of pretreatment and treatmenttechnologies to enable a beneficial use (in the sense ofenvironmental policy) of the DM cost-efficient againstupland dumping?” Usually the use of treatment technologies is only cost-efficient when the contamination is so high, that thematerial has to be dumped upland on a waste facility.

LAGA classificationsIn Germany the LAGA (federal government/federalstates expert group for waste) has drafted a regulationfor the beneficial use of mineral residuals includingcriteria for upland dumping of soil material (LAGA,1994). A classification with the classes Z0 (unrestricteduse) to Z5 (hazardous waste facility) is defined bycontaminant concentration values in the solids and theeluate. A classification of the DM in Z2 and higherapplies the dumping on a waste facility. There arespecial regulations for dumping material on a municipalwaste facility (TASi, 1993) or on a hazardous wastefacility (TA Abfall, 1991), which accept only consolida-ted and dewatered material.

Furthermore, a special restriction on municipal wastedumps is the limit set for the ignition loss (as a mea-sure for all organic substance) at 3% (= LAGA-class Z3)or 5% (= LAGA-class Z4), aiming to keep the formationof digestion gases low. Problems for DM are foresee-able, in particular for highly polluted wet dredged mate-rial, as the ignition loss in contaminated dredged mate-rials is practically always higher than 5%. Furthermorethe material has to have a stability of a minimum shearstrength of 20 KN/cm2 (TASi, 1993).

Because most of the highly contaminated dredgedmaterial is wet, fine-grained and contains organic mat-ter, it has to be treated at very high costs to render itsuitable for dumping on these waste facilities. Fromthe dumping of sewage sludge, which has some simi-larities in composition with wet, fine-grained dredgedmaterial (sediments), it is known that the total costs pertonne (dry weight) for waste dumping (including treat-ment, transport and dumping) ranges regionallybetween 1,500 and 2,000 German marks (Drescher,1995; Wittchen and Püschel, 1995).

Under these circumstances it is obvious that suitable

Ranking destinationsFrom the view of cost-efficiency a general ranking ofdestinations can be made (Figure 6). Beneficial use – asintended by waste and environmental policies – is notalways the cheapest solution compared with disposal,especially when treatment technologies are needed.

Sometimes this raises problems between the compe-tent authorities who issue the permits, and the projectowner who has to deal with a limited budget. In projectson Federal Waterways for instance, the project owneris an subordinated office of the government. In this case the project owner receives the money forthe project from the Federal Budget. The project ownerhas to take care that the costs for the project do notexceed the budget given for the project. On the otherside the competent authorities for permits, which arefunded by public money to take care for the environ-ment, often have to impose cost-relevant demands intheir permits, which may prohibit the cheapest solu-tion. In order to deal carefully and responsibly with theFederal Budget and the environment, a compromisebetween economy and ecology is needed. Conse-quently, the question is: “How much do we want tospend for the protection of environment?” Because theFederal Budget is limited it may be better to ask: “On which other values do we want to renounce tofinance the protection of the environment?” Decisions on these questions have to be made on apolitical level. The purpose of a DMM scheme is not tomake policy, but to bring the project on the practicaland technical level to an economically and ecologicallyacceptable solution.

First realistic destination alternatives in the vicinity ofthe dredging area have to be found. Depending on localand regional circumstances not every possibility is ofcourse practicable.

Using the flowchartA use-dependent assessment of the collected datafrom the survey helps to decide whether the plannedsolution is environmentally acceptable or not (Figure 6).To find the most cost-efficient possibilities one has tostart in Pathway 1 in Figure 6). If relocation in the wateror direct beneficial use is not possible, one has to startwith other alternatives in Pathways 2 and 3, which willbe more expensive. In general, one can say in thedirection towards Pathway 3, ever more technicalrequirements are needed in the handling-train. For instance in the case of Pathway 1 it is possible thatresidues have to be introduced into other pathways(1.1, 1.2, 1.3 in Figure 6). This is less expensive thanhandling the whole volume on another, generally morecost-intensive pathway.

The subaquatic placement of dredged material (Path-way 2, Figure 6) in suitable gravel pits (Koethe andBertsch, 1996) or in confined disposal sites (Vellinga,


23

and cost-effective pretreatment and treatment technol-ogies have to be chosen, which change the chemicaland physical composition of the contaminated dredgedmaterial for an environmentally acceptable beneficialuse (Koethe, 1995b). This aim can be reached at con-siderably lower costs compared with the dumping onwaste facilities. The magnitude of these costs can beroughly estimated between 100 and 500 Germanmarks per tonne. In general one can say the bigger thevolumes for treatment are, the cheaper is the cost pertreated tonne.

For less contaminated material (LAGA-class Z2 andlower) mono-dumps for dredged material with lowertechnological requirements are often chosen. Uplandmono-dumps for dredged material are less expensivecompared with the costs for dumping on waste facilities including the use of treatment technologies.

Depending upon the technical requirements the costsare more or less clearly less than 50 German marks/m3.Another important reason to prefer mono-dumps lies in the physical composition of the DM. In contrast tocoarse DM, beneficial uses without treatment arerarely possible with wet, fine-grained sediments. The aim of environmental policy to protect dumpingcapacities will not be reached for this dredged material,which is a considerable portion of the total volumebeing dredged annually, as long as dumping solutionsoutside waste facilities are cheaper than solutionsincluding treatment technologies.

Conclusion: Outlook

There is no doubt, the fastest way to reach the targetvalues for water and sediment quality intended by theenvironmental policy is to close the sources of pollutionand to observe discharges into the rivers and water-ways very carefully. Clean dredged material can be relocated in the water ormay be used for many beneficial purposes withoutdanger for the environment, when this is done properly.

Until this objective is met, more or less contaminateddredged material has to be handled in a very complexprocess, that is organised and executed in form of adredged material management (DMM) scheme. In thesense of waste and environmental policy, pretreatmentand treatment technologies have to be included, preferentially in those projects where they have a cost-efficient effect too.Besides the technical project control, a good dredgedmaterial management has the function of an eco-controlling too, which helps to work cost-efficiently.Together with a strong responsibility for the environ-ment the chances are very good that a compromisebetween ecology and economy can be found for everyproject on a case-by-case decision.

References

Arge Elbe Umgang mit belastetem Baggergut an der Elbe, Zustand und

Empfehlungen.- Ad-hoc AK Baggergut; Wassergütestelle Elbe;

Hamburg. 1996. (Management of contaminated dredged material

at the river Elbe, present situation and recommendations).

Deutscher Staedtetag Statistisches Jahrbuch deutscher Gemeinden, 80. Jg. 193; Koeln.

1993. (Statistical yearbook of German municipalities).

DIN 19731 “Bodenbeschaffenheit - Verwertung von Bodenmaterial”. DIN

Deutsches Institut für Normung e.V., Normenausschuß Wasser-

wesen (NAW); Berlin. (Soil quality - utilisation of soil material).

Drescher, D. Maßnahmen zur vollständigen Klärschlammverwertung beim

Abwasserverband Saar.- gwf Abwasser Special II, 136, Nr.15:

32-39. 1995. (Measures for the complete utilisation of sewage

sludge in the Wastewater Association Saar-Region)

HABAK-WSV Handlungsanweisung zur Anwendung der Baggergut-Richt-

linien der Oslo- und der Helsinki-Kommission in der Wasser-

und Schiffahrtsverwaltung des Bundes.- Bundesanastalt für

Gewaesserkunde, BfG-0700, 102 S., Koblenz, Berlin. 1992.

(Directive for the Application of the OSLO AND HELSINKI

Guidelines on the Disposal of Dredged Material).

HABAB-WSV Handlungsanweisung fuer den Umgang mit Baggergut aus dem

Binnenland.- Bundesanastalt für Gewaesserkunde Koblenz.

Draft 1996. (Directive for the management of dredged material

in federal inland waterways).

Koethe, H.“Legislative framework and technological improvement for the

management of contaminated dredged material in Germany”.

Paper for the 5th KfK/TNO Conference on Contaminated Soil

in Maastricht (30 Oct- 3 Nov 1995). 1995a.

Koethe, H. “Criteria for the beneficial use or the disposal of contaminated

dredged material in the Federal Republic of Germany”.

Proceedings of the XIVth World Dredging Congress Dredging

Benefits, 14-17 Nov 1995, Amsterdam, The Netherlands. 1995b.

Koethe, H. and Bertsch, W.“Legal and technical requirements in Germany for the subaqua-

tic disposal of contaminated dredged material in gravel pits”.

Proceedings of the International Congress CATS III: Characteri-

sation and Treatment of Sludge, March 18-20, 1996, Ostend,

Belgium. 1996.

Kreislaufwirtschafts- und Abfallgesetz KrW-/AbfG vom 27. September 1994, BGBl I S 2705.

(Waste Recycling Act).


24

Thibodeaux, L.J., Reible, D.D. and Valsaray, K.T. “So you want to remediate contaminated mud! These are your

five choices.” Proceedings of the Second International Confer-

ence on Dredging and Dredged Material Placement. Volume 1,

pp 588-595. Lake Buena Vista, Florida, USA. ASCE,

New York. 13-16 November 1994.

Van Der Veen, R. “Contaminated Sediment Remediation, Dredging polluted bed

materials - A study of environmentally effective dredging

methods” (draft report). North Sea Directorate, Directorate-

General for Public Works and Water Management (Rijkswater-

staat); The Netherlands. 1993.

Vellinga, T. “Treatment and beneficial use of contaminated sediment, past

and present: Port of Rotterdam case study”. European Water

Pollution Control. Volume 5, number 5, p. 31-37. 1995.

WaStrAbG - Wasserstrassenausbausgesetz (E. 1995): Entwurf eines Gesetzes ueber den Ausbau der

Bundeswasserstraßen und zur Aenderung anderer Gesetze.-

Bundesministerium fuer Verkehr, Entwurf vom 20.02.1995;

Bonn. (Draft Act on development construction of Federal

Waterways and on amendments of pertinent other laws).

Wittchen, F. and Püschel, M. Ausgangsituation und Zielstellung der Klärschlammbehand-

lung und -entsorgung.- gwf Abwasser Special II, 136, Nr.15:

22-31. 1995. (Initial situation and objectives of sewage sludge

treatment and disposal).

Laboyrie, H.P. “The construction of large scale disposal sites for contaminated

dredged material”. Proceedings of XIVth World Dredging

Congress “Dredging Benefits, 14-17 Nov 1995, Amsterdam,

The Netherlands. 1995.

LAGA - Länderarbeitsgemeinschaft AbfallAnforderungen an die stoffliche Verwertung von mineralischen

Reststoffen/Abfällen. Technische Regeln (Stand: 7 September

1994). (Requirements for the beneficial use of mineral residuals).

Palermo, M. “Equipment choices for dredging contaminated sediments”.

Remediation, Autumn 1991, p. 473-492. 1991.

PIANC Handling and treatment of contaminated dredged material from

ports and inland waterways”, Volume 1. Report of PIANC-PTC

I-WG No.17. Brussels, Belgium. 1996.

PIANC Handling and treatment of contaminated dredged material from

ports and inland waterways”, Volume 2. Report of PIANC-PTC

I-WG No.17. Brussels, Belgium. 1997 in preparation.

Rokosch, W.D.“Dredging: A clean up technique for contaminated aquatic

sediments”. Terra et Aqua, number 50, January 1993.

Schudoma, D.Ableitung von Zielvorgaben zum Schutz oberirdischer Binnen-

gewässer für die Schwermetalle Blei, Cadmium, Chrom, Kupf-

er, Nickel, Quecksilber und Zink.- Erarbeitet im Auftrag des

Bund/Länder-Arbeitskreises „Qualitätsziele“ (BLAK QZ);

Umweltbundesamt Berlin. 1993. (Development of target values

for the heavy metals lead, cadmium, chromium, copper, nickel

and zinc for the protection of inland waters).

TASi - Technische Anleitung SiedlungsabfallDritte Allgemeine Verwaltungvorschrift zum Abfallgesetz

(TA Siedlungsabfall). Technische Anleitung zur Verwertung,

Behandlung und sonstigen Entsorgung von Siedlungsabfaellen

vom 14. Mai 1993.- Bundesministerium der Justiz [Hrsg.],

Bundesanzeiger Jhrg.45, Nr. 99a vom 29.05.1993; Bonn.

(Technical Instruction for Municipal Waste. Third administrative

ordinance on the utilisation, treatment, or other disposal of

municipal wastes).

TA Abfall - Technische Anleitung AbfallGesamtfassung der Zweiten allgemeinen Verwaltungsvorschrift

zum Abfallgesetz (TA Abfall). Teil 1: Technische Anleitung zur

Lagerung, chemisch/physikalischen, biologischen Behandlung,

Verbrennung und Ablagerung von besondes ueberwachungs-

beduerftigen Abfaellen vom Maerz 1991.- GMBl Nr.8, 139-214;

Bundesminister f. Umwelt, Naturschutz u. Reaktorsichrheit

[Hrsg.]. 1991. (Technical Instruction for Waste. Part 1: Techni-

cal instruction for the storage, chemical/physical, biological

treatment, incineration, and dumping of wastes requiring special

surveillance).


25

International Seminars on Dredging andReclamation 1997Delft, Singapore and Buenos Aires

In association with the Universidad Nacional de La Plataand Estudio de Ingenieria Hidráulica S.A., the Interna-tional Association of Dredging Companies (IADC) willorganise its intensive, one-week course on dredgingand reclamation in Buenos Aires, Argentina. This pastFebruary in Singapore the IADC in cooperation with theNational University of Singapore (NUS) and the AppliedResearch Corporation (ARC) presented the seminar forthe third time. And in March 1997 the IADC and theInternational Institute of Hydraulic Engineering (IHE)joined forces to present the programme for the fifthtime in Delft, The Netherlands.

By combining the expertise of the universities with thatof the dredging companies, the IADC hopes that thesepostgraduate students and professionals will gain abetter understanding of the need for dredging, and thepositive effects dredging can have on an area's econo-my, environment and the quality of life.

Each year at the Delft and Singapore course locations,participants from many parts of the world are able totake part in the course. In Delft this year participantsfrom India, Bangladesh, Sri Lanka, Tanzania, Turkey,

as well as Vietnam, China PR, Philippines, Cuba, Israeland Egypt were represented. In Singapore the studentscame primarily from Indonesia, Malaysia, Singaporeitself, Korea, although people from Bahrain, SouthAfrica, the UK, France, and even Mexico and Ukrainewere enrolled.

New in 1997 -- Buenos AiresIn an effort to reach beyond Europe and Asia, the IADChas now decided to extend this seminar to SouthAmerica -- Buenos Aires, Argentina to be exact -- wherethe course is scheduled to be held the week of Octo-ber 13-17, 1997.

As at the other programmes, the five-day course inBuenos Aires will be divided into two types of presen-tations: - classroom lectures by experts in the field, and - workshops in which the students confront real-lifedredging situations.

Amongst the subjects to be covered are:- the development of new ports and maintenance ofexisting ports;

- project phasing (identification, investigation, feasibilitystudies, design, construction, maintenance);

- descriptions of types of dredging equipment andboundary conditions for their use;

- state-of-the-art dredging techniques as well asenvironmentally sound techniques;

- pre-dredging investigations, designing and estimatingfrom the contractor’s view;

- costing of projects and types of contracts such as char-ter, unit rates, lump sum and risk-sharing agreements;

A day-long visit on board a dredger to an actual worksite is an added highlight of the week and will give theparticipants the opportunity for a firsthand experience.

Parties interested in enrolling in this short course inBuenos Aires are encouraged to contact the IADCSecretariat in The Hague for details as soon as possi-ble, or complete the application form on page 32.


26

Participants in the International Dredging Seminar enjoy a dayon board a dredger in the Ijsselmeer at a reclamation site forthe extension of the city of Almere, The Netherlands.

Charles W. Hummer, Jr.

Books/PeriodicalsReviewed

- the reports on operational results of heretoforeexperimental bathymetric methods such as SHOALS and TIBS, both of which appear to be moreeffective than earlier reported.

Paper 17 on the introduction of an integrated systemfor the Port of Conakry in Africa was particularly inter-esting both in terms of approach, scope and reportedresults. Likewise, the case-like reports from the Port ofHamburg (Paper 7) and Aberdeen Harbour (Paper 6)were very useful and instructional with potential appli-cation to other ports and situations. All of the papers ondigital global positioning systems (DGPS) and therapidly growing application of multibeam acousticsounding equipment coupled with on-board data pro-cessing were excellent.

Although outside the realm of technology, it was notedwith interest that Paper 4 on the privatisation of portsand the technology subsequently adopted, involved thecontinued use of port-owned rather than contractordredgers and support equipment.

For the dredging community, these proceedings are anexcellent source of maintaining currency in the manyaspects of hydrographic surveying and related areas ofinterest.

The A4 size publication makes the type and figuresreadable to a greater extent than smaller book-sizedpublications. For all of the foregoing reasons, it is arecommended acquisition for most individuals, organi-sations and companies involved in hydrographic sur-veys, dredging, manufacture and sales of related equip-ment and/or systems and academia. Although a fact of life when organising a technicalconference where the organisers are at the mercy ofthe authors, it is always disappointing to note thatsome papers are represented only by their abstracts ofshort summaries. Those papers where this was thecase are noted in the listing below.

Port & Coastal Hydrography, HYDRO ’96.Proceedings of The Tenth Biennial InternationalSymposium of The Hydrographic Society. (Special Publication No. 36). 294 pp. Illustrated.

The Hydrographic Society, Benelux Branch

This biennial conference is an opportunity for interna-tional experts in the field of hydrography to participatein the presentation of technical papers and discussions.The proceedings of such conferences are uniqueopportunities to capture the most recent and relevantadvances in the field. As is generally the case through-out the realm of engineering, science and technology,the advances in computers, communications andmultidimensional geographic positioning has resulted ingreat leaps in the state-of-the-art and practices in hydro-graphic surveying. These proceedings typify the docu-mentation of these advances.

The conference was held over a period of three fulldays in Rotterdam, The Netherlands, in September1996. The programme was divided into 5 technicalsessions with the papers presented at each grouped bysubject matter, with those papers which did not fallclearly into any one group or apparently were morepolicy oriented being presented in the last session.

A total 34 of papers are summarised in the proceed-ings. They are of a generally high quality and certainlyare of value to those in the field of dredging and marineconstruction. A complete listing of the papers is shownbelow. The preponderance of papers were of highinterest and applicability to dredging activities. Some ofthe reports on the application of experimental methodswere very optimistic in being applied to routine opera-tions. This was true as it relates to:- the use of high frequency (HF) and standard naviga-

tion radar to determine water current and bottomsurface mapping;

- the use of satellite imaging to determine bathyme-try; and

Books/Periodicals Reviewed

27

Session I: PORT HYDROGRAPHYPaper 1: Progress by IHO (International

Hydrographic Organisation) and itsMember States on a WorldwideElectronics Navigational Chart Data-base (WEND).

Paper 2: The Waterdepth ManagementSystem, a tool to use hydrographicdata for nautical admission purpos-es.

Paper 3: A new generation of instrumenta-tion for hydrographic launches.

Paper 4: The Bristol Port – Port developmentin the mid-nineties

Paper 5:(*) Up and running in 18 months –Experience of the Hong KongHydrographic Office.

Paper 6: Automation of hydrographic surveysa Aberdeen Harbour and the bene-fits.

Paper 7: HydroCAD: the first step of the GISfor the Port of Hamburg – Basicinformation for prospective applica-tions.

Paper 8: “Diver Shoal” – A scheme to im-prove channel depths within acritical area of the River Thames.

Session II: NEW TECHNOLOGYPaper 9: ADCP (Acoustic Doppler Current

Profiler) current measurement in thehorizontal plane.

Paper 10: The application of shore-based HFradarsystems for mapping seasurface currents in the Dutch coas-tal zones.

Paper 11: Wave and current measurementswith a navigation radar.

Paper 12: The Bathymetry Assessment Sys-tem – to assess depths from (satel-lite) radar imagery.

Paper 13: The Towed Inflight BathymetrySystem (TIBS) – airborne electro-magnetic bathymetry.

Paper 14: Two years of operating the SHOALS airborne hydrographic lidarsurvey system.

Session III: DREDGING AND SILTPaper 15: Dredging survey strategy for an

intake pipeline in karstic limestone.Paper 16; New survey techniques for silt

density measurement systems.Paper 17: Technical cooperation with ports

in West Africa – supervision of dredging operations in the Port ofAutome de Conarky (PAC) Guinea –an integrated approach.

Session IV: 3D POSITIONINGPaper 18: DGPS vertical postioning for ship

squat and trim determinationPaper 19: On-the-fly GPS for vertical control of

hydrographic surveys.Paper 20: Dual Antenna GPS/Inertial integra-

tion provides precision attidue, trueeading and position for multibeamsystems.

Paper 21: GPS Tides and Water Levels.Paper 22: Assessing the integrity of electronic

chart systems for berthing andmanoeuvring inconfined waterways– a prudent perspective.

Session V: MULTIBEAM SONARSPaper 23: What are the future trends in multi-

beam technology?Paper 24: Applications of shallow water multi-

beam systems in NOAA hydrogra-phic surveys.

Paper 25:(*) A review of interferometer tech-niques in seafloor mapping.

Paper 26: A new generation of multibeamsweeping echosounder for sur-veying – ATLAS FANSWEEP 20.

Session V: SPARE PAPERSPaper 27: Progress by IHO (International

Hydrographic Organisation) and FIG(FQdQration Internationale desGQomFtres) on technical coope-ration for hydrography.

Paper 28:(*) IHO and other technical organi-sations working together to bringimproved technology to port development.

Paper 29:(*) The promulgation of maritime safetyinformation.

Paper 30:(*) New standards for the IHO forhydrograpic surveying.

Paper 31:(*) Water uprising of Van and HazarLake (Turkey-Azerbaijan) and theeffects to the environment.

Paper 32:(*) Digital data transfer of tide informa-tion: an absolute necessity.

Paper 33:(*) Port environment information sys-tems.

Paper 34: Research for Optimal FairwayManagement with respect to Silta-tion.

(*) denotes papers that were represented by abstractsor short summaries in the proceedings.

This publication may be ordered from:The Hydrographic Society, Benelux BranchRijkswaterstaat - Noordzee DirectorateP. O. Box 5807 2280 HV Rijswijk, The Netherlands


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Seminars/Conferences/Events

Conference topics include: Harbour planning and con-struction design; port operation and maintenance;advancement construction technologies; coastal engineering and management; environmental issues;and monitoring and modelling.A two day Seminar on Port Managment will be heldwith lectures on the themes:Port Management -- the challenge of the 21st century;Long-term strategic planning; Port privatisation; Berthleasing and charge structures; and Creating additionalincome from ports. An exhibition of specialised software, computer relatedproducts and services, and monitoring and hydrograp-hic survey equipment will accompany the conference.

For further information contact:PCE’97 Bulgarian Coastal Association“Valdislav Varenchik” 63-a, 9000 Varna, Bulgariatel. +359 52 250 058, fax +359 52 256 701telex +77 500 BG

Coastal Zone ’97Boston Park Plaza Hotel,

Boston, MassachusettsJuly 20-26 1997

This is the tenth in a series of biennial internationalconferences with the permanent theme “Spotlights onSolutions”, and takes place during the 25th anniversaryof the enactment of the Coastal Zone ManagementAct. The conference entitled “Charting the Future ofCoastal Zone Management” will examine the issues ofcoastal zone management over the last 25 years, andattempt to define goals for the next 25 years. Domesticand international planners, public and private policymakers, non-governmental organisations, business andindustry, managers and scholars are all invited to partici-pate.

For further information contact:Dr Martin C. MillerUSAE Waterways Experiment Station, Attn: CEWES-CR-O, 3909 Halls Ferry Road, Vicksburg, MS 39180 USA

WEDA XVIII Conference Charleston Place, Charleston, South Carolina

June 28-July 3 1997

The Western Dredging Association’s Eighteenth Annual Meeting and Technical Conference and the30th Texas A&M Annual Dredging Seminar will have as its theme, “Dredging: The International Business”.Subjects at this annual meeting and exhibition willinclude amongst others:consortiums for large dredging jobs; dredging environ-mental issues in the US and abroad; Jones Act andforeign hulls; capping of contaminated sediments;remediation technologies; innovations in dredgingtechnologies; deep water dredging; and mining andoffshore islands and causeways.An exhibition of dredging and marine construction-related equipment and displays will also be on exhibit.

For further information about the exhibiton contact:L.M. PatellaWestern Dredging AssociationPO Box 5797, VAncouver, WA 98668-5797, USAtel. +1 360 750-1186/ +1 503 285 5521fax +1 360 750 1445/ +1 502 240 2209

For conference information contact:Robert E. RandallDepartment of Civil EngineeringTexas A&M University, College Station, TX 77843-4568, USAtel. +1 409 845 4568

Port - Coast - EnvironmentVarna, Bulgaria

June 30-July 4 1997

The First International Conference on Port - Coast -Environment organised by the Bulgarian Coastal Asso-ciation and the Environmental Engineering & SafetyCentre, Moscow State Technology University, Russia.The conference will provide a forum for informationexchange on port development, coastal managementand environmental protection.


29

International Conference on Land Reclamation andRehabilitation (LARREN ’97)

Penang, MalaysiaAugust 25-28 1997

The School of Civil Engineering, Universiti Sains Malaysia, Perak Branch Campus, in cooperation withthe Department of Environment, the Mines ResearchInstitute, and The Institution of Engineers, all of Malaysia, and the University of Newcastle upon Tyne(UK) are organising a conference on new technologiesin land reclamation and rehabilitation. Areas to be covered are: geotechnics, geology, environ-mental engineering, hydrology, water resources, soilscience, agriculture, biology, aquaculture, civil engineer-ing (construction) and forestry.A trade exhibition will be organised in conjunction withthe conference.

For further information contact:Land Reclamation and RehabilitationSchool of Civil Engineering, Universiti Sains Malaysia,Perak Branch Campus31750 Tronoh, Perak, Malaysiatel. +605 367 6901, fax +605 367 7440email: [email protected]

Pacific Coasts and Ports ’97 Christchurch Convention Centre

Christchurch, New ZealandSeptember 7-11 1997

The purpose of the conference is to provide an interna-tional forum for coastal, ocean, port and harbour, engineering, scientific and management issues. Topics will include: coastal oceanography and meteorolo-gy; coastal sediment processes; shore protection;coastal structures and environment; harbours andports; and coastal zone management. Five well-recognisedkeynote speakers have been invited from Australia, Canada, Japan and the USA.

The conference is being organised by the New ZealandCoastal Society incorporating the 13th AustralasianCoastal and Ocean Engineering Conference and the6th Australasian Port and Harbour Conference.

For further information please contact:Megan O’BrienConference Innovators, P.O. Box 10330Christchurch, New Zealandtel. +64 3 379 0390, fax +64 3 379 0460email: [email protected] or visit the conference website athttp://www.cae.canterbury.ac.nz/coastal/pacific.htm

International Conference on Contaminated SedimentsCongress Centre “De Doelen”

Rotterdam, The NetherlandsSeptember 7-11 1997

The International Conference on Contaminated Sedi-ments (ICCS) is an excellent opportunity for gover-nments, port authorities, the industry and academia topresent and discuss their problems with and solutionsfor contaminated sediments. Subjects will include,national policies and strategies; site investigations; thefate of contaminants; physico-chemical analysis; risksand quality criteria; ecological effects, management andcontrol; treatment technologies (in situ and ex situ);disposal of dredged material; beneficial uses of dredg-ed material; and source control strategies.

For further information please contact the conferencesecretariat:Van Namen & WesterlakenCongress Organization ServicesP.O. Box 1558, 6501 BN Nijmegen, The Netherlandstel. +31 24 323 4471, fax +31 24 360 1159

Offshore Europe ’97Aberdeen Exhibition and Conference Centre

Aberdeen, ScotlandSeptember 9-12 1997

This Oil and Gas exhibition and conference is organisedby the Offshore Europe Partnership -- a partnershipbetween Spearhead Exhibitions Ltd and the Society ofPetroleum Engineers. The theme of the conference is“Continuous Change -- Learning from the 21st Centu-ry”. Technical papers and panel discussions are plan-ned on: Time to Market; Commissioning and Decom-missioning; Exploration: Deeper Water, DeeperTargets; Innovative Technology; Reservoir Manage-ment; Beyond CRINE.

For further conference information contact:Val Johnston-Jones, Society of Petroleum Engineers4 Mandeville Place, London W1M 5LA, UKtel. +44 171 487 4250, fax +44 171 487 4229email: [email protected]

Exhibitors include manufacturers and providers ofservices relevant to the technical and operatingmanagement of offshore oil and gas exploration andproduction companies, drilling contractors, and offshoreengineering contractors. For information about theexhibition contact:Offshore Europe PartnershipOcean House, 50 Kingston RoadNew Malden, Surrey KT3 3LZ, UKtel. +44 181 949 9222, fax +44 181 949 8168/8193email: [email protected]


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Call for PapersWODCON XV, “Dredging Into the 21st Century”and Exhibition

Las Vegas, Nevada, USAJune 28-July 2, 1998

This announcement is a call for papers for the four-daytechnical programme and exhibition with the theme“Dredging Into the 21st Century”. Suggested topicsinclude but are not limited to: computerised dredging;dredge automation; disposal of dredged materials;beneficial uses of dredged material; environmentalissues; dredging and the economy. Interested authorsshould submit a one-page abstract to the TechnicalPapers Committee, which will review all submissionsand notify authors of acceptance. Papers must besubmitted to be included in the proceeding which willbe published prior to the Congress. Submission dead-lines are: Abstracts must be received by October 30,1997; authors will be notified by December 1, 1997; final manuscripts must be submitted by March 1, 1998.The conference will be accompanied by an Exhibitionof dredging and marine construction-related equipment/displays which will also be hosted by the Western Dredging Association (WEDA).

For further information about submitting a paper orabout hiring boot please contact: Executive Director, Western Dredging AssociationPO Box 5797, Vancouver, WA 98668-5797, USAtel. +1 360 750 1445, fax +1 360 750 1445 ortel. +1 503 285 5521, fax +1 503 240-2209

ConSoil ’98Edinburgh International

Conference Centre, ScotlandMay 17-21 1998

The Sixth International FZK/TNO Conference on Contaminated Soil will be taking place in May 1998.The fifth conference in 1995 in Maastricht saw anattendance of 1000 delegates from 31 countries. The siers focusses on policies, research, development,regulations, practical implementations and experiencesrelated to contaminated sites. ConSoil ’98 is organisedby Forshungszentrum Karlsruhe (FZK) and the Nether-lands Organisation for Applied Scientific Research(TNO) in cooperation with Scottish Enterprise.

For further information about submitting papers orattending the conference please contact: Forshungszentrum Karlsruhe -- PSAPO Box 3640 D-76021 Karlsruhe, Germanytel. +49 7247 82 3967, fax +49 7247 82 3949email: [email protected]: http://www.iai.fzk.de.soil98/

Europort 97Rai Congress Centre

Amsterdam, The NetherlandsNovember 18-22 1997

Europort is one of the major international marine exhibi-tions and marketing events in Europe. Its participantsinclude all those involved in ship operations; shipdesign and construction; port and harbour building andoperation; design, construction and operation of ves-sels for inland waterways; and dredging. The eventtakes place every other year and attracts hundreds ofparticipants and many thousands of visitors from allover the world. IADC has been asked to function aspart of the Exhibition Committee.

For further information please contact:Europort 97Amsterdam RAI, Post Box 777771070 MS Amsterdam, The Netherlandstel. +31 20 549 1212, fax +31 20 646 4469

CEDA Dredging DaysRAI International Exhibition

and Convention CentreAmsterdam, The Netherlands

November 20-21 1997

Continuing a tradition started in 1980, “CEDA DredgingDays” will take place during the Europort Exhibition ’97week in Amsterdam. This year’s theme is “New Developments in DredgingEquipment and Technology”. The emphasis will beupon innovative solutions which achieve higher effi-ciency, increased accuracy, cost-effectiveness andenvironmental compliance. Presentations, delivered by highly qualified invitedspeakers, with long-standing international experience,will cover various aspects of dredging with specialemphasis on the improved results achieved throughthe use of innovative equipment and techniques. An International Technical Paper Committee appointedby CEDA will invite authors to present and publish theirpapers. A panel discussion will follow the presenta-tions.The Annual General Meeting of CEDA will be held afterthe conference, but the conference itself is open toanyone concerned with dredging.

Please address all enquiries to: Secretariat of CEDAPO Box 3168 2601 DD DelftThe Netherlandstel. +31 15 278 3145, fax +31 15 278 7104email: [email protected]


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Day 1: Why Dredging?The Need for Dredging/Project Phasing

Day 2: What is Dredging?Dredging Equipment/Survey Systems

Day 3: How Dredging?Dredging Projects

Day 4: Preparation of DredgingContract

Day 5: Cost/Pricing and Contracts

Representatives of port authorities, companies, andindividuals interested in attending are requested tocomplete the preliminary registration form below assoon as possible and prior to September 1 1997, andreturn to:

IADC Secretariat, Duinweg 21,2585 JV The Hague, The Netherlandstel. 31 (0)70 352 3334, fax 31 (0)70 351 2654telex 31102 (dune nl)

Place: Buenos Aires, ArgentinaDate: October 13-17, 1997

In cooperation with the Universidad Nacional de LaPlata and Estudio de Ingenieria Hidráulica S.A., theInternational Association of Dredging Companies ispleased to organise for the first time in Buenos Aires anintensive, one-week seminar on dredging and recla-mation. This seminar has been successfully presentedfor the last five years in Delft, The Netherlands with theInternational Institute for Hydraulic Engineering, and forthe third time in Singapore with the National Universityof Singapore and the Applied Research Corporation.The costs are US$ 2950, which includes six nightsaccommodation at the conference hotel, breakfast andlunch daily, one special participants dinner, and a gene-ral insurance for the week.

The seminar includes workshops and a site visit to adredging project. Highlights of the programme are:

International Seminar onDredging and Reclamation

(please print)

Name ..........................................................................................................................................................................

Title ..........................................................................................................................................................................

Company ..........................................................................................................................................................................

Address ..........................................................................................................................................................................

..........................................................................................................................................................................

Tel. ................................................................................... Fax ...............................................................................

Please send this form and your deposit by cheque or credit card for US$ 500 in order to guarantee your place atthe seminar. Upon receipt of this form and your deposit your place in the seminar is confirmed. We will then sendyou further detailed information, final registration forms, and an invoice for the correct amount.

Without your deposit we cannot guarantee your place and accommodations at the seminar.

■■ A Cheque is enclosed.

■■ Please charge my credit card:

■■ American Express ■■ Eurocard/Master Card ■■ Diners Club

Account no.:

Expiry date:

Signature .............................................................................................................. Date ................................................

AfricaBoskalis South Africa (Pty.) Ltd., Capetown, South AfricaBoskalis Togo Sarl., Lomé, TogoBoskalis Westminster Cameroun Sarl., Douala, CamerounDredging International Services Nigeria Ltd., Lagos, NigeriaHAM Dredging (Nigeria) Ltd., Ikeja, NigeriaNigerian Dredging and Marine Ltd., Apapa, NigeriaWestminster Dredging Nigeria Ltd., Lagos, NigeriaZinkcon Nigeria Ltd., Lagos, Nigeria

The AmericasACZ Marine Contractors Ltd., Brampton, Ont., CanadaBeaver Dredging Company Ltd., Calgary, Alta., CanadaDragamex SA de CV, Coatzacoalcos, MexicoGulf Coast Trailing Company, New Orleans, LA, USAHAM Caribbean Office, Curaçao, NANorham/Consub S.A., Rio de Janeiro, BrazilStuyvesant Dredging Company, Metairie, LA, USAUscodi, Wilmington, DE, USA

AsiaBallast Nedam Malaysia Ltd., Kuala Lumpur, MalaysiaBallast Nedam Dredging, Hong Kong Branch, Hong KongBoskalis International BV., Hong KongBoskalis International Far East, SingaporeBoskalis Taiwan Ltd., Hualien, TaiwanDredging International N.V., Hong KongDredging International N.V., SingaporeFar East Dredging Ltd., Hong KongHAM Dredging (M) Sdn Bhd, Kuala Lumpur, MalaysiaHAM East Asia Pacific Branch, Wanchai, Hong KongHAM Singapore Branch, SingaporeHAM Taiwan Office, Taipei, TaiwanHAM Thai Ltd., Bangkok, ThailandJan De Nul Singapore Pte. Ltd., SingaporeMumbai Project Office, Mumbai, IndiaPT Penkonindo, Jakarta, IndonesiaTideway DI Sdn. Bhd., Selangor, MalaysiaVan Oord ACZ B.V., Dhaka, BangladeshVan Oord ACZ B.V., Hong KongVan Oord ACZ B.V., SingaporeVan Oord ACZ Overseas B.V., Karachi, PakistanVomsi India Ltd., New Delhi, IndiaZinkcon Marine Malaysia Sdn. Bhd., Kuala Lumpur, MalaysiaZinkcon Marine Singapore Pte. Ltd., Singapore

Middle EastBoskalis Westminster Al Rushaid Ltd., Dhahran, Saudi ArabiaBoskalis Westminster M.E. Ltd., Abu Dhabi, UAEDredging International N.V., Middle East, DubaiDredging International N.V., Tehran Branch, Tehran, IranGulf Cobla (Limited Liability Company), Dubai, UAEHAM Dredging Company, Abu Dhabi, UAEHAM Saudi Arabia Ltd., Jeddah, Saudi ArabiaJan De Nul Dredging, Abu Dhabi, UAEVan Oord ACZ Overseas BV., Abu Dhabi, UAE

AustraliaCondreco Pty. Ltd., Sydney, NSW, AustraliaDredeco Pty. Ltd., Bulimba, QUE., AustraliaJan De Nul Australia Pty. Ltd., Brisbane, QUE., AustraliaNew Zealand Dredging & General Works Ltd., WellingtonVan Oord ACZ B.V., Victoria, AustraliaWestHam Dredging Co. Pty. Ltd., Sydney, NSW, Australia

EuropeACZ Ingeniører & Entreprenører A/S, Copenhagen, DenmarkAnglo-Dutch Dredging Company Ltd., Beaconsfield,United KingdomA/S Jebsens ACZ, Bergen, NorwayAtlantique Dragage S.A., Nanterre, FranceBaggermaatschappij Boskalis B.V., Papendrecht, NetherlandsBaggermaatschappij Breejenbout B.V., Rotterdam, NetherlandsBallast Nassbaggergesellschaft, Hamburg, GermanyBallast Nedam Dredging, Zeist, NetherlandsBallast Nedam Dragage, Paris, FranceBoskalis Dolman B.V., Dordrecht, NetherlandsBoskalis International B.V., Papendrecht, NetherlandsBoskalis Oosterwijk B.V., Rotterdam, NetherlandsBoskalis Westminster Aannemers N.V., Antwerp, BelgiumBoskalis Westminster Dredging B.V., Papendrecht, NetherlandsBoskalis Westminster Dredging & Contracting Ltd., CyprusBoskalis Zinkcon B.V., Papendrecht, NetherlandsBrewaba Wasserbaugesellschaft Bremen mbH, Bremen, GermanyCEI Construct NV, Afdeling Bagger- en Grondwerken, Zele, BelgiumDelta G.m.b.H., Bremen, GermanyDraflumar SA., Neuville Les Dieppe, FranceDragados y Construcciones S.A., Madrid, SpainDravo S.A., Madrid, SpainDredging International N.V., Madrid, SpainDredging International N.V., Zwijndrecht, BelgiumDredging International Scandinavia NS, Copenhagen, DenmarkDredging International (UK), Ltd., Weybridge, United KingdomEnka-Boskalis, Istanbul, TurkeyEspadraga, Los Alcázares (Murcia), SpainHAM Dredging Ltd., Camberley, United KingdomHAM, dredging and marine contractors, Capelle a/d IJssel,NetherlandsHAM-Van Oord Werkendam B.V., Werkendam, NetherlandsHeinrich Hirdes G.m.b.H., Hamburg, GermanyHolland Dredging Company, Papendrecht, NetherlandsImpresa SIDER SpA., Rome, ItalyJan De Nul N.V., Aalst, BelgiumJan De Nul Dredging N.V., Aalst, BelgiumJan De Nul (U.K.) Ltd., Ascot, United KingdomNordsee Nassbagger- und Tiefbau GmbH, Wilhelmshaven,GermanyN.V. Baggerwerken Decloedt & Zoon, Brussels, BelgiumPhilipp Holzmann Aktiengesellschaft, Hamburg, GermanyS.A. Overseas Decloedt & Fils, Brussels, BelgiumSider-Almagià S.p.A., Rome, ItalySkanska Dredging AB, Gothenborg, SwedenSociedade Portuguesa de Dragagens Lda., Lisbon, PortugalSociedad Española de Dragados SA., Madrid, SpainSocietà Italiana Dragaggi SpA. “SIDRA”, Rome, ItalySociété de Dragage International “S.D.I.” S.A., Marly le Roi, FranceSodranord SARL, Paris, FranceTideway B.V., Breda, NetherlandsVan Oord ACZ B.V., Gorinchem, NetherlandsVan Oord ACZ Ltd., Newbury, United KingdomVan Oord ACZ B.V., Zwijndrecht, BelgiumVolker Stevin Baggermaatschappij Nederland B.V.,Rotterdam,NetherlandsVolker Stevin Dredging B.V., Rotterdam, NetherlandsWasserbau ACZ GmbH, Bremen, GermanyWestminster Dredging Co. Ltd., Fareham, United KingdomZanen Verstoep B.V., Papendrecht, NetherlandsZinkcon Contractors Ltd., Fareham, United KingdomZinkcon Dekker B.V., Rotterdam, NetherlandsZinkcon Dekker Wasserbau GmbH, Bremen, Germany

Membership List IADC 1997Through their regional branches or through representatives, members of IADC operate directly at all locations worldwide.

INTERNATIONAL ASSOCIATION OF DREDGING COMPANIES

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