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The The issue of Sediment Management is rising on the European agenda. Sediment topics will be an element of River Basin Management Plans to be published in 2009 under the Water Framework Directive. Sediment Management is also an important part of the work of a European Working Group on Estuary Management, organised by DG Environment of the EU Commission. Furthermore, sediments are explicitly mentioned in new EU legislation, like the Directive on Environmental Quality Standards in the field of water policy, the Marine Strategy Directive, and the Waste Directive.
In Europe the largest amounts of sediments have to be dredged in the North Sea region, where the natural sediment regime in the sea leads to high sedimentation in ports, harbours and waterways. Additionally, sediments gain in importance due to sea level rise and loss of fine grained sediments in the Wadden Sea.
On this background SedNet organised its 6th International two-day Conference on Sediment Management in the city of Hamburg to which 150 sediment experts participated.
In Hamburg ongoing river restoration challenges coincide with dredging needs and sediments play a central role. The region is a good example to discuss cross-cutting science-policy issues.
At the beginning of the conference a report was given from the SedNet Round Table Discussion on “Implementation of sediment management issues into the first RBM Plans”.
On day 3, the day after the conference, a Special Session with the title “Managing the Elbe Estuary” was held, covering local challenges and solutions in sediment management.
A poster session formed part of the program during 7-8 October. Springer and the Journal of Soils and Sediments were sponsoring a prize for the best poster. The prize consisted of 250 Euros of Springer books and a free online subscription to the Journal of Soils and Sediments.
The winning poster was “Measurement and modeling of polychlorinated biphenyl bioaccumulation from sediment for a marine polychaete and response to sorbent amendment” by Elisabeth Janssen, Stanford University, USA.
On the website – www.sednet.org – you will find the abstracts and slides of the presentations.
SedNet conference 2009: Session “Report and Key-note presentations”
The conference was opened by Axel Netzband, Chairman of SedNet, and Jens Meier, managing director of the Hamburg Port Authority as co-organiser of the conference.
It was followed be a report from the SedNet Round Table Discussion “Implementation of sediment management issues into the first RBM Plans”, given by Piet den Besten, SedNet Steering Group.
(see separate article further down in this newsletter).
The title of the presentation of Francois Kremer, European Commission / DG Environment was “Natura 2000 and estuaries”. Estuaries and coastal zones are among the most productive ecosystems of the world, with both high ecological and economic values. As Natura 2000 sites they are subject to the protection regimes under the ‘Habitats Directive (92/43/EEC) and/or the ‘Wild Birds Directive’ (79/409/EEC). Inevitably there will be occasions where port and waterways developments and Natura 2000 conservation objectives collide. The directives lay down procedures for ensuring that such developments are done in a sustainable way that is compatible with the conservation of species and natural habitats for which the Natura 2000 sites have been designated.
Since now more than two years the European Commission has been working with stakeholder organisations and environmental NGOs with a view to developing guidelines and recommendations on the implementation of the EU nature legislation in estuaries and coastal zones and for avoiding conflicts between Natura 2000 objectives and economic development needs. Human activities in estuaries include ports & navigation, dredging, sand mining, fisheries, industry, wind farms, flood protection, recreation, urbanism, etc.
Mr. Kremer acknowledged the concept of ‘Working with nature’ of PIANC, the World Association for Water borne Transport Infrastructure. The concept has a focus on achieving project objectives in an ecosystem context rather than assessing consequences of a pre-defined design (-> integrated management) and on identifying win-win solutions rather than simply minimising ecological harm (-> partnership).
So the title of the next presentation “Building with nature” of Martin Scholten, IMARES, The Netherlands, fit perfectly well. EcoShape is a Dutch National Innovation Programme for the time period 2008-2012, partners are from both science, industry, and administration. The main objectives are to develop scientifically sound design rules and norms enabling ‘building with nature’ using practical examples.
Mr. Scholten reported about a shift towards an ecosystem based approach: Ecodesign based on the natural dynamics. It means a turn around from a defensive approach to minimize environmental impacts to an offensive approach in order to optimize full economic and ecologic potential. This means to design a project on the basis of understanding the ecosystem dynamics and functioning as well as on the understanding of ambitions, opinions, concerns and discourse amongst stakeholders in the social system.
A project should be planned in coherence with other functions, such as coastal defence, aquaculture, sand and gravel extraction, land reclamation, nature development or restoration, etc. In the planning it should be determined how natural processes can be used and stimulated to achieve the goals. Project execution should give room for adaptation of the project.
SedNet conference 2009: Session “Conceptual approaches”
The SedNet Roundtable that preceded the Conference recognized the need of developing conceptual models of sediment fluxes and contaminant transport to provide a better understanding of the system. In this respect the session on conceptual approaches provided a good overview of actions taken in Canada and UK to create a basis for sustainable sediment management.
Suzan Roe presented the assessment and management framework of sediments in Canadian waters, which is currently under development by the Canadian federal government in cooperation with provincial governments. The aim is to incorporate into the framework the elements of existing assessment and management tools. Within the framework, sediment quality guidelines may be adjusted to account for intended use (i.e., in cases of pollution prevention, a high level of protection is desired while for remediation of contaminated sites, a clean-up target that will help restore ecological function is required).
Kevin Black informed on a management framework that will provide stakeholders in UK with guidelines for the management of contaminated marine sediments in UK waters. The framework will collect information on all relevant data, liability issues, impacts of legislation, pollution prevention methods, contaminated sediments disposal options and future research areas. The implementation of the framework in the UK ports and harbours will reflect the principles of sustainable environmental management.
Sediment risk ranking and management framework and tool development and evaluation was presented by Susan Casper. Adapting DPSIR-based sediment models developed for a number of catchments and a sediment-specific adaptation of the relative risk model, a generic framework is under development in UK to support decision-making in deriving a catchment sediment management plan. This includes evaluation of measures for reducing risk to catchment management objectives in support of the WFD.
Sabine Apitz discussed different aspects of building a decision framework for management of a dredged material in light of a specific scientific and political situation. Various factors influencing the decision framework performance such as chemical action levels, selection of biotests, combination of data and tests and reference conditions changes were addressed.
SedNet conference 2009: Session “Management and Policy”
The session on Management and Policy began with a keynote of Beate Ratter (University of Hamburg / GKSS, Germany) on people’s perception of natural hazards. Beate Ratter concentrated on coastal geoharzards and here especially on the storm surge that hit Hamburg in 1962. For a hundred years (1855–1962) there had not been an extreme flood event. Subsequently, people were little aware of that risk, and the city was unprepared to fight the water and to protect its people. Since today, the flood of 1962 is well imprinted on people’s minds even though there have been higher water levels since then which – due to higher dikes – did not do much damage. Only recently, an extensive new urban area, the “HafenCity” (harbour city) has been allowed to be built in the Hamburg port area – at the water front.
The keynote was followed by a presentation of Amy Oen (NGI, Norway) which continued along the line of public risk perception. Giving details on a controversial sediment management disposal site in Oslo harbour, Amy demonstrated the importance of including the public and addressing its perception in making decisions on sediment management options. Conclusions have been drawn from the challenges, that the process in Oslo had to face, and consequences for coming remediation projects in e.g. Bergen include the establishment of a stakeholder panel early in the process and transparent multicriteria decision making to identify potential remediation alternatives. (Presentation: “Sediment and Society: assessing approaches for including stakeholder interests and contaminated sediment management”).
The next talk by Andrea Barbanti (Thetis SpA, Italy) also demonstrated experiences and lessons learned from former activities, in this case sediment management in the Venice lagoon (“The sediment management issue in the Venice lagoon: lessons learned and future perspectives”). Andrea focussed in his talk on the challenge to connect science and policy making with the final goal of having scientifically sound management solutions. His major criticism being that the technical protocol used for assessing dredged material is outdated and should have been revised for quite some time. He gave conceptual, technical, and administrative recommendations on what to change but clarified the present limitations and difficulties. He concluded that more sustainable and holistic approaches with an updated scientific base would be needed in order to come up with an improved sediment management concept that would help to preserve and restore coastal ecosystems such as the Venice lagoon in future.
Jos Brils (Deltares, the Netherlands) ended this session describing “The EU environmental policy shift towards sustaining of ecosystem services and its possible implications for sediment management”. Jos demonstrated the shift from conservation of single species in the 1970s to preservation of ecosystem services which we know today to be – together with the protection of biodiversity – the core of EU environmental policy. He stated that so far application of the underlying concepts has been scarce – especially for sediment management issues. Often the matrices sediment, soil and water all contribute to specific ecosystem services complicating the issue. A way forward would be to carry out a comparative analysis of projects and real world cases concerned with these topics in order to extract from there a practical guidance to facilitate implementation of the EU environmental policies.
SedNet conference 2009: Session “Risk and Monitoring”
The session started with a presentation of Oscar van Dam focusing on hydro morphological challenges in the WFD and the link to sediments. Both quantity and quality of sediments are closely interfering with hydro morphological conditions and thus with the ecological potential of a water body. Sediments are an essential part of hydro morphological monitoring but the way that it is included differs a lot and should be improved if the data needs to support the implementation and evaluation of a program of measures. Typical measures, which are clearly linked to sediment as part of the hydromorphology, are dredging activities and the creation of new habitats by sand suppletion.
Monitoring the ecotoxicological risk of sediments is not incorporated in the WFD, but several other international guidelines focusing on dredged material emphasise the importance of ecotoxicological testing of the sediments in addition to chemical, physical and biological characterization as was shown by Carolin Floeter. However the results of the ecotoxicological sediment assessment in the Port of Hamburg that was carried so far was linked with high uncertainty. The results showed high variability and the classification itself was based on the result of the most sensitive test, irrespective of the results of the other tests. Therefore a new concept is under construction in which the ecotoxicological risk assessment is better harmonised and validated.
Birgit Schubert gave an overview of chemical monitoring of sediments and suspended solids in estuarine environments in Germany. This monitoring is mainly carried out in function of dredging activities and to study the transport of fine particulate matter. The results showed clearly that sediment quality is improving in the estuary in downstream direction, but also that recently deposited sediments are containing lower concentrations of metals such as cadmium. This can be explained by an increased upstream transport of marine particulate matter into the estuary but also due to the fact that the suspended solids coming from upstream river basins are less contaminated.
Transport of contaminated sediments was also the focus of the presentation of Jos Van Gils. It was shown that due to the mixing of cleaner marine suspended solids with contaminated freshwater suspended solids in the estuarine environments, net fluxes of contaminants to the North Sea are overestimated if these take not into account this mixing. It was shown also that achieving the Water Quality Objectives (WQO) for priority pollutants in coastal waters in 2015 or even 2027 can only be successful when the transport of contaminated suspended solids and the exchange of contaminants between water, suspended solids and the sediment is considered. This was clearly shown by the timeframe that TBT concentrations are exceeding the WQO in the years after 2008 when the application of TBT containing antifouling paints is. Exceedence will occur much longer due to the interaction between the water and the sediment.
SedNet conference 2009: Session “Sediment Management”
This session comprised of four talks. It started with a key-note presentation given by Giovanni Cecconi who considered the role of sediments as a fundamental resource in coastal areas, especially in systems affected by sea level rise and erosion. Based on the results of works conducted in the Venice lagoon during more than twenty years he demonstrated that wind, wave and tide driven sediments can settle and be stabilized by stimulating natural processes creating a variety of structuring and self-preserving habitats, such as beaches, dunes, salt marshes, eel-grass prairies, and inter-tidal flats. The second presentation by Yves M.G. Plancke focussed on the morphological management of the Western Scheldt. The concept developed by an expert team from the Antwerp Port Authority aims both at improving the morphological status of the estuary and at reducing the quantity of dredged material. Since 2002 the new strategy is being investigated a pilot project on the Walsoorden sandbar. The present results are promising both in terms of economy and ecology. The following presentation was given by Gunnel Göransson. She emphasised the role of extreme events, partly caused by climate changes, and their impact on the risk for mass failure. How prepared are we to meet such events? Based on the climate change scenarios for the Swedish west coast, calculations clearly indicate an increase in the risk for mass failure of sediment. Possible hydraulic effects as well as effects to the water quality have to be considered, which in term may have consequences for a variety of uses. Tools are needed to manage such events of low frequency but high magnitude. In his last presentation, Renaat de Sutter dealt with climate change and socio-economic impacts on the long-term sediment balance in the Belgian part of the North Sea. Preliminary results of two ongoing projects were presented. The one project aims at differentiating the anthropogenic climate change effects from the natural evolution at the North Sea scale. The other focuses on sedimentation/erosion processes on different scales both in terms of geography and time.
SedNet conference 2009: Session “Sediment Balance and Transport”
This session comprised of 3 presentations.
The first presentation by Jens Laugesen dealt with the use of tracer particles as a new technique to monitor and quantify transport of contaminated sediments. This was tested in two studies in Norway. These studies show that it is a promising technology. The method needs however a large amount of sediment samples which have to be analysed for tracer particles to be able to give good results. A further refinement of the technology is necessary.
The second presentation by Sabine Gerbersdorf focussed on biological engineering and its consequences for sediment stability and floc entrainment and transport. The study shows that bacterial assemblages cannot be neglected when considering mircrobial sediment stabilization and secondly, that a change in abiotic conditions can affect their stabilization potential significantly. This is of particular importance when considering the expected changes due to climate change in the future. Next to this the characteristics of the eroded flocs have shown distinct patterns depending on the biological origin, with severe consequences to sediment transport and –deposition.
The last presentation by Benjamin Dewals showed a modelling system, handling the wide range of time scales involved in sediment transport processes. It described a modelling system dedicated to depth-averaged simulations of flow and sediment transport, as support for sustainable management of sediments. As a result of the flexibility offered in the levels of coupling between flow and sediment transport models, stable and accurate numerical solutions are obtained for predictions of erosion and sedimentation patterns in the short, medium or long term, considering both bed load and suspended load.
SedNet conference 2009: Special Session “Managing the Elbe Estuary”
In a Special Session “Managing the Elbe Estuary” on Friday, 9th October 2009, participants of the SedNet conference were invited to learn about the tidal Elbe and its environmental and economic importance for the port of Hamburg. Comprehensive maintenance operation for a safe navigation and environmental protection of the sensitive natural habitats along the 100km long tidal Elbe is a challenging task for all involved stakeholders. The related management concepts and their diverse aspects were the key issues of this special session which was attended by 75 participants.
Heinz Glindemann from Hamburg Port Authority held an illustrative introductory speech on challenges and visions affiliated with the Elbe estuary from a user’s perspective. Hydrodynamic changes during the past decades claim permanent attention to the Elbe estuary and the port of Hamburg, especially in terms of water level and sediment management. As part of his speech Heinz Glindemann introduced the “Tideelbe” concept which combines the elements (1) attenuation of the tidal energy through river engineering, (2) implementation of more tidal volume and (3) an optimized sediment management of the river. New measures such as the pilot project “Spadenlander Busch” were presented to demonstrate the possibility for improving the hydrological situation of the river Elbe through new tidal areas within the city of Hamburg (www.tideelbe.de).
The following presentation by Harro Heier from the Federal Waterways Engineering and Research Institute (BAW) articulated the need for tools to improve the predictability of river basin processes and sediment management strategies, especially under consideration of future tasks such as the sealevel rise because of climate change. Due to Harro Heyer this could be achieved through the analysis of more tidal parameters on the basis of mathematical model results.
An overview on the Natura 2000 managementplan for the Elbe estuary was given by Elisabeth Klocke, Ministry for Urban Development and Environment, Hamburg.
The crucial issue of sediment management within the area of Hamburg and its harbor was shown in respect of relating environmental issues. An integrated concept including the steady adjustment of the relocation strategy and monitoring scheme in reconciliation with environmental administrations and NGOs was suggested.
Sediment management measures in the port of Hamburg were presented by Claudia Flecken, head of the division Port Infrastructure, Hamburg Port Authority. The presentation clarified, that dredging operation is a key element for guaranteeing safe navigation in the port of Hamburg. Hamburg Port Authority implemented a land treatment concept which includes operation of the METHA, the largest treatment plant for dredged material worldwide.
Finally participants of the Elbe Session were given the opportunity to visit the METHA plant and the Francop land disposal site for sediments. The fieldtrip was accompanied by presentations of Heinz-Dieter Detzner (Overview), Ulrich Döring (METHA) and Hubert Urich (Francop land treatment).
Linked to the Hamburg SedNet Conference, a Round Table discussion was held 6 and 7 October 2009. This Round Table discussion built on the results of the SedNet Round Table Discussion on River Basin Sediment Management held in Venice in 2006 (see/roundtable). In the SedNet e-newsletter special on river basin management plans (spring 2009 – see our website – pdf) the SedNet steering group concluded: “These few pages on WFD compliant River Basin Management and sediment management show a great variety. The river basins are different in size and challenges, and the solutions are as diverse as the recognition of sediments in the plans is.”
On this background SedNet organised another Round Table discussion preceding the Hamburg conference. The goal was to discuss the position of sediment management in water management and in regional or local developments and to explore new pathways to effectively link sediment management initiatives to RBMP’s.
The invited participants represented river commissions, governmental bodies, water agencies, port authorities, research institutes, consultancies, NGO’s, etc. Rivers represented where Douro, Ebro, Danube, Sava, Drava/Mura, Elbe, Rhine, Scheldt and Thames. The program of the Round Table was based on the outcome of a questionnaire sent earlier to the participants and an illustrative river basin case. During two days, a large number of topics were covered: holistic system understanding, dealing with uncertainty, better linkage of sediment management to WFD objectives or to other plans, communication (especially about the link between sediments and ecosystem integrity), stakeholder involvement and ecosystem services as a model to help the stakeholder process.
A report about the outcome of the Round Table discussion will be prepared and is intended to be available spring next year. It is also thought to be base for the development of a guidance document that should explain how to include sediment management in River Basin Management Plans, with examples that demonstrate how sediment management makes RBM more effective.
Published in the Journal of Soils and Sediments: Volume 9, Issue 5 (2009), Page 393.
Since its foundation in 2002, it has been the aim of SedNet, the European Sediment Network, to communicate on the importance of sediments at both the scientific and the political level. The unusual but beneficial property of SedNet is that, in the steering group, scientists work alongside harbour managers and representatives of environment administrations, which results in sometimes necessarily controversial, but always constructive discussions. With the round table event in Venice in 2007, we facilitated an exchange amongst stakeholders from a number of European rivers on the integration of sediment-related issues into River Basin Management Plans (RBMP), as required by the Water Framework Directive (WFD). In 2009, we organize another round table in order to examine recent experiences with regard to addressing sediment issues at the river basin scale.
In the interim, in May 2008, a conference was held in Oslo, Norway, which focused on experiences and scientific assessments of sediment management issues at local and river basin scales. The major conclusions from this conference can be viewed at/events/sednet-conference-2008/. A short introduction to the conference was presented by Förstner and Heinrich (2009), and a special issue on the Norwegian cases addressed at the conference will be published in Journal of Soils and Sediments in 2010.
Why then this article? As all presentations and abstracts can be downloaded from /library/sednet-conference-5/, we will not summarize each presentation. Instead, with this article, we would like to draw the conclusions from the individual sessions further and put them into the perspective of the scientific and political discussion 1 year after the conference.
Full article available on SpringerLink.
In 2005, analysis of dredged material from the Upper Rhine indicated a too high degree of sediment contamination. Thus, in 2005 a coordinated sediment management plan for the Rhine was commissioned. The result we now dispose of is the first plan for an international river basin district giving a global survey of the contamination of sediments in the main stream of the Rhine and in its main tributaries.
The sediment management plan for the Rhine is based on the following classification:
(1) In a first step, the most important contaminants and the areas polluted by them were identified.
(2) In a second step, sedimentation areas with more than 1000 m³ of contaminated sediments were identified. These sedimentation areas are called „areas of concern“, if there is no natural or man-made risk of re-mobilisation.
(3) In a third step it was investigated, in how far a re-mobilisation of contaminated sediments is liable to detrimentally impact the good status of water bodies further downstream. For these investigations, the assessment of the risk of re-mobilisation due to floods, wind, and anthropogenic impacts (dredging, navigation) plays an important role. In cases of considerable contamination and great amounts of sediments liable to be re-mobilised the area is classified as area presenting a risk.
18 of the 93 analysed sedimentation areas have been classified as „areas of concern“, 22 as areas presenting a risk. For areas presenting a risk, decontamination measures will be presented while it is recommended to intensively monitor the “areas of concern”.
The summary can be dowloaded here.
TThis is likely to remain reality unless we boost our ambition and boost our willingness to learn-by-doing. In its final events in Brussels (16 November) and Mechelen (17 & 18 November) the EC FP6 project RISKBASE advocated that the actual improvement of the ecological quality of our river basins, and thus sustaining of the ecosystem services they provide, calls for a different approach to river basin management. This approach involves the integrated application of the three key-principles to risk-based management: informed, adaptive and participatory.
Informed: a sound understanding of the functioning of the natural soil-sediment-water system and of its interaction with the social system is the basis to river basin management. EC projects, like FP6 AquaTerra and Modelkey, have delivered new, natural system understanding, relevant to support the achievement of the WFD objectives. They identified not yet (1st RBMPs) addressed sources of risk and deliver knowledge for improving of the effectiveness of measures. AquaTerra demonstrated, for example, that contaminated ground water hinders good status achievement of surface water and that flooding mobilizes historic contamination from floodplain soils and river bottom sediments, thus hindering status achievement. A remaining and ongoing challenge is to connect this new science to management and policy making.
Adaptive: we have to learn-by-doing as social/natural systems are extremely complex and dynamic and can respond in non-linear and unexpected ways.
Participatory: involvement of stakeholders will improve management, e.g. because they may bring in local knowledge. However, involvement of stakeholders calls for the use of a common language to enable participation. RISKBASE believes that the ‘ecosystem services’ approach provides that language.
RISKBASE has observed that leading initiatives, like the management of the Llonsko-Polje catchment (part of the Sava basin in Croatia), already demonstrate some of these aspects. However, more well coordinated and monitored pilot projects (aimed at stepwise improving of the effectiveness of measures) are needed to transform our general framing and develop best practice. The WFD also demands that we learn from the experiences in the 1st RBMP. In WFD, annex VII (page 67) it is stated: “The first update of the river basin management plan and all subsequent updates shall also include: … an assessment of the progress made towards the achievement of the environmental objectives, … and an explanation for any environmental objectives which have not been reached.”
By the end of 2009 a brochure/booklet will be made available via the RISKBASE website in which the key-messages are further elucidated. The more detailed motivation and duly scientific underpinning of the key-messages can be found in a scientific book that will be published by Springer next year. For more information, please visit the RISKBASE website or contact the RISKBASE coordinator: Jos Brils, email:firstname.lastname@example.org
The LOICZ report entitled “Dynamics and Vulnerability of Delta Systems” discusses the changes and vulnerabilities of world deltas resulting from anthropogenic alteration of upstream freshwater and sediment inflows; anthropogenic alteration of sediment and water routing through deltas; hydrocarbon and groundwater extraction from deltas; sea-level change; and the increased frequency of extreme climate events. Download here (pdf).
ThRecently published: “Erosion, Transport and Deposition of Sediment – Case Study Rhine”.
CHR, 2009. Erosion, Transport and Deposition of Sediment – Case Study Rhine. Spreafico M., Lehmann C. (Eds.). Contribution to the International Sediment Initiative of UNESCO/IHP. Report no II-20 of the International Commission for the Hydrology of the Rhine Basin (CHR). ISBN 978-90-70980-34-4.
The report can be ordered or downloaded via this link (scroll down to II-20).
SProjected climatic conditions for Germany may favour both increased flood frequencies and severities, which in return may lead to a re-mobilisation of contaminated sediments in rivers. The research project „Risks from cohesive sediments“ is part of the recently established research program KLIWAS (2009-2013) by the German Federal Ministry of Transport, Building and Urban Affairs. The project aims to develop tools for estimating and mitigating risks from cohesive sediments by an integrated research approach that combines the expertise of the scientific fields of environmental chemistry and hydraulic engineering. The research area covers the Rhine and Elbe catchments. The Upper Rhine has been identified as an “area of risk“ by the International Commission for The Protection of the Rhine because of historic hexachlorobenzene contaminations. Similarly, the Mid-Elbe is focussed on because of heavy metal and PCB pollution.
The methodology comprises laboratory sorption experiments for deriving basic physico-chemical parameters of pollutants, time-continuous, in-situ measurements of suspended matter based on turbidity as well as acoustic backscatter, and the application of various hydraulic transport models (HT-models) within a model cascade. Regional climate projections are used within KLIWAS as input for hydrologic catchment models to produce runoff and water level data. This output is then used to run different HT-models on various scales. The 3D-model SSIIM is employed for small-scale simulation of the Upper Rhine impoundments to estimate re-suspension and sedimentation of hexachlorobenzene. The MIKE software suite is used for modelling the Mid-Elbe including the complex interaction of the open stream and groyne fields. Finally, the SOBEK River model that was developed by DELTARES is used for long term, meso-scale simulations of particle bound contaminant transport. The work is conducted in close collaboration with environmental agencies, research centers, and universities; e.g. the Elbe modelling is conducted by the Hamburg University of Applied Sciences. The project contributes to a fundamental understanding of river systems that is essential for successful river sediment management.
T. Pohlert, G. Hillebrand, V. Breitung, S. Vollmer
Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, PO Box 200253,
D-56002 Koblenz, Germany
PThe Gesellschaft Deutscher Chemiker (GDCh) is the largest chemical society in continental Europe with members from academe, industry and other areas. The society was founded in 1949 but builds on a long tradition that began in 1867 when its first predecessor organization, the Deutsche Chemische Gesellschaft was founded in Berlin. The work of the society is structured by divisions and working groups, among them the Waterchemical Society. Under the umbrella of the Waterchemical Society in 2002 a working group on “Sediments and Water quality” was established. The recent meeting of this group was held in November 2009 in Frankfurt/Main. One of the topics dealt with the role of stable isotopes in following sediment dynamics.
Stable isotopes as natural tracers for river and sediment dynamics
Stable isotopes ratios of water (18O/16O, D/H) and carbon (13C/12C of dissolved inorganic, and particulate as well as dissolved organic carbon) were analysed in various river systems including the St. Lawrence (Canada) and the Lagan River (N. Ireland) and the Elbe River in Germany. For instance, mass balances calculations with stable water isotopes helped to outline the relative importance of water masses in an ecologically important embayment in the St. Lawrence River. It showed that despite inland influxes of a small stream and groundwater input, the main channel of the St. Lawrence had a strong influence on this ecosystem most times of the year. This has important implications for transport of chemical goods on the main channel. Discrepancies between stable isotope ratios of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) showed that most of the suspended sediment carbon was generated inside the St. Lawrence River through phytoplankton activity. In a similar manner such mass balances showed contributions for estuarine and inland river water as well fluxes as groundwater in the Elbe River (Germany) during the millenium flood in 2002. In another study on the Lagan River in Northern Ireland a noticeable influence of carbonates on the dissolved load of inorganic carbon could be demonstrated via stable carbon isotope analyses. Further differentiation between photosynthetic enrichment in 13C of the DIC might be outlined with stable isotope analyses of dissolved oxygen. The presented studies show that stable isotopes are ideal biogeochemical tracers to quantify exchanges of water masses as well as turnover of carbon in rivers and suspended and bottom sediments. Such techniques can further apply to German rivers with particular focus on smaller river systems that have more potential to clearly outline endmembers of influence.
Professor Johannes Barth, PhD
Lehrstuhl für Angewandte Geologie, GeoZentrum Nordbayern,
Schlossgarten 5, D- 91054 Erlangen / Germany
Terra et Aqua Is a free magasin published by the International Association of Dredging Companies. Sediment experts can find regularly interesting articles in the magazine.
Please click link below to download Terra et Aqua 115:
73 per cent of the world’s 33 major river deltas are sinking, according to new research. Results indicate that the sinking is worsened by the impacts of human activity, such as upstream sediment collection caused by reservoirs, dams, accelerated sediment compaction, and control of river channels.
About 500 million people live in or near river deltas, which are formed when rivers deposit sediment as they flow into the sea. The 2007 Intergovernmental Panel on Climate Change1 report concluded that many deltas will experience sea level rises due to climate change. The effects of twentieth century development and population growth will also increase the risk of deltas flooding. The EU’s Floods Directive aims to assess and manage areas at risk of flooding, including coast lines2.
The research analysed high resolution satellite data, historical maps and infrared images of 33 world river deltas. Four of these were EU deltas, in Italy, France, Poland and Romania. The results indicated that 85 per cent of deltas experienced severe flooding in the past decade, causing 260,000 km2 of land to be temporarily submerged.
The study investigated the possible role of compaction of sediment in the increase in flooding, particularly compaction caused by human activities, such as removal of gas and water, trapping of sediments upstream in reservoirs and floodplain engineering. For example, the Po Delta in Italy subsided 3.7 metres in the twentieth century; 81 per cent of this is attributed to methane mining. This research is the first to estimate the volume of sediment delivered to the deltas both before and after substantial human activity.
The results demonstrated that sediment delivery has been reduced or eliminated at the majority of the deltas. Much of this can be attributed to upstream damming, e.g. in the Ganges (India) and the Mekong (Vietnam). Another factor is the reduction in the number of side channels. The number of distributary channels has dropped for 13 of the major deltas, including the Vistula (Poland) and the Nile (Egypt) which both suffered a 70 to 80 per cent reduction in distributary channels.
This reduction in sediment delivery has caused deltas to sink and makes them more vulnerable to flooding from sea level rises. A few deltas have remained largely unchanged over the twentieth century, such as the Amazon (Brazil) and the Congo (Western Africa).
The research also identified three categories of delta, listed in order of increasing risk of flooding:
1. Those with decreasing sediment deposition that can no longer keep up with local sea level rise, e.g. the Vistula (Poland), the Brahmani (India) and the Godavari (India)
2. Those with decreasing sediment deposition plus accelerated compaction of sediment, e.g. the Ganges and the Mekong.
3. Those with virtually no sediment deposition or very high compaction of sediment, e.g. the Po (Italy), the Rhone (France) and the Nile (Egypt).
Altogether, the surface area of delta that is vulnerable to flooding could increase by 50 per cent under IPCC projections for sea level rise in the twenty-first century. The flooding will increase further if sediment continues to be trapped upstream by reservoirs and other human activities.
Source: Syvitski, J.P.M., Kettner, A.J., Overeem, I. et al. (2009). Sinking deltas due to human activities. Nature Geoscience. Doi: 10.1038/NGE0629
• The EU Floods Directive
• Results of the EU Eurosion project in the brochure ‘Living with coastal erosion in Europe: Sediment and Space for Sustainability’
• SedNet (The European Sediment Network)
tThe quality of surface water is best assessed using the status of both the water and underlying sediment. A recent study concluded that water bodies risk being misclassified if sediment assessment is not included, which can lead to unnecessary recovery costs.
Under the Water Framework Directive1 (WFD), Member States are required to achieve at least ‘good water status’ for surface water (inland, estuarine and coastal water bodies) in Europe by 2015. Surface water quality is assessed on both its ecological status and chemical status. Ecological status includes the physical and chemical conditions that affect the water’s biological quality, such as nutrients and oxygen levels. The chemical status is also determined according to levels (or environmental quality standards (EQS)) of important pollutants, including metals, found in the water, as listed under the EC’s Directive2 on priority dangerous substances.
In this study, Spanish researchers investigated the quality of Basque coastal and estuarine waters in northern Spain. The study focused on the long-term trend (from 1995-2007) of water and sediment contamination by metal pollutants (arsenic, cadmium, copper, chromium, mercury, nickel, lead and zinc) and the response of these areas to water treatment programmes.
In addition, the chemical status of these water bodies was assessed using two approaches: (1) following the principle of ‘one out, all out’ under the WFD, whereby any metal in waters over the EQS will result in the whole station failing to achieve the chemical status (and for concentrations below the EQS, the chemical status is met), and (2) Combining the chemical quality of both the surface waters and the underlying sediment, using a methodology proposed by these researchers.
The river catchments, estuaries and coastal waters of the study area have been polluted by urban and industrial discharges, particularly from iron ore mining in the region. Additional pollution comes from the construction of ports, dredging, sediment disposal, and land reclamation. Emission control measures and water treatment programmes have been implemented to help tackle these pressures.
Using the first approach, few of the water bodies achieved good status, and the percentage of systems meeting this status falls over time. Using the second approach, more than 50 per cent of the water bodies achieved ‘good status’, with the percentage of systems meeting this status remaining steady over time.
The researchers argue that the second approach is more accurate in assessing chemical status as it is better at discriminating between less polluted water, which has less impact on wildlife, and that which is highly polluted. In addition, this approach reflects the drop in pollution of river catchments in recent years, which has improved water quality in many bodies.
By considering both water and sediment analysis in determining the status of water quality, resources could better be targeted at those bodies of water where levels of pollution have a greater negative effect on fish and other living organisms in the water. However, the researchers say further research is needed on EQS measurements in water and the interpretation of chemical concentrations of contaminants in sediments.
Source: Tueros, I., Borja, A., Larreta, J. et al. (2009). Integrating long-term water and sediment pollution data, in assessing chemical status within the European Water Framework Directive. Marine Pollution Bulletin. 58:1389-1400.
First phase of Hudson River dredging project complete
(From the US-EPA website)
The dredging work of the first phase of the Hudson River cleanup concluded in late October, after five-and-a-half months of dredging in a six-mile stretch of the Upper Hudson River near Fort Edward in New York State.
General Electric Co. (GE) conducted the dredging, with EPA oversight, and the company targeted 265,000 cubic yards (cy) of PCB-contaminated sediment. During Phase 1, dredging occurred 24 hours a day, six days a week, with the seventh day reserved for maintenance and make-up time for unplanned project interruptions. Dredging was conducted 133 days between May 15 and October 26, 2009. Backfilling and capping in some areas will continue through November 2009, until the Champlain Canal closes for the season.
Phase 1, the first year of dredging, was designed to address approximately 10 percent of the material to be dredged over the six-year project timeframe. At the end of Phase 1, an estimated 293,000 cy of PCB-contaminated sediment had been removed from the river. Although the volume of dredged sediment exceeded established goals for Phase 1, not all of the dredge areas originally targeted for Phase 1 were completed, (10 out of 18 areas were completed) due to sediment contamination in some areas that was deeper than expected. The presence of woody debris and PCB oil in the sediment also made the Phase 1 work challenging. Phase 2 will begin with the dredge areas that could not be completed during Phase 1.
Rail transport of the dewatered sediment from GE’s processing facility to a PCB-approved landfill in Andrews, Texas will continue through fall and winter 2009. Habitat reconstruction work will be conducted in the completed Phase 1 areas in spring 2010. Phase 2 will start full production only after an evaluation of Phase 1 is made and reviewed by the public and an independent panel of experts. Phase 2 is expected to begin in 2011 and will address the remaining contamination over five years.
The European Geosciences Union (EGU) annual conference is probably the main annual conference in Europe for sediment research. In 2010, the conference will be in Vienna again and will run between 2nd and 7th May 2010. There are many sessions dedicated to sediment-related research, mainly in the Hydrological Sciences (HS) and Geomorphology (GM) divisions. Below are some of the main sediment-related sessions. The call for abstracts is open to the public. The deadline for submission is early January 2010. For further details, please see here.
26-28 April 2010: Integrated River Basin Management Conference; action programs and monitoring under the Water Framework Directive. Lille, France.
2-7 May 2010: European Geosciences Union (EGU) annual conference, Vienna, Austria.
11-13 May 2010: 2nd International Symposium on Sediment Management, Casablanca, Morocco www.amce.ma
23-27 May 2010: SETAC Europe annual meeting, Seville, Spain.
Abstracts can be submitted until 30th November 2009.
9–14 September 2010: A conference of the World Organisation of Dredging Associations, WODCON XIX, Beijing, China. Organised by EADA in association of its Chinese Chapter, CHIDA.
A Call for Papers will be issued early 2009. See furtherhttp://www.woda.org/
22-24 September 2010: ConSoil 2010 – 11th UFZ-Deltares/TNO conference on the management of soil, groundwater and sediment. Call for abstracts open until 21 December 2009. http://www.consoil.de
19-23 June 2011: 12th International Symposium on the Interactions between Sediments and Water, Dartington, Devon, England. Organised by the International Association for Sediment Water Science (IASWS)
http://www.IASWS.org and www.geog.plymouth.ac.uk/IASWS2011
Mrs. Marjan Euser
Deltares / TNO
P.O. Box 342
NL-7300 AH Apeldoorn