Marine Habitat Committee ICES CM 2002/E:06 Ref. D, ACME ACE
Report of the
Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem
Boulogne-sur-Mer, France 9–13 April 2002
This report is not to be quoted without prior consultation with the General Secretary. The document is a report of an expert group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council.
International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer
Palægade 2–4 DK–1261 Copenhagen K Denmark
TABLE OF CONTENTS Section Page
1 INTRODUCTION...... 1 2 TERMS OF REFERENCE, OPENING OF MEETING AND ADOPTION OF AGENDA...... 1 3 REVIEW OF NATIONAL MARINE AGGREGATE EXTRACTION ACTIVITIES...... 1 4 REVIEW OF NATIONAL SEABED RESOURCE MAPPING PROGRAMMES...... 2 5 REVIEW OF DEVELOPMENTS IN NATIONAL AUTHORISATION AND ADMINISTRATIVE FRAMEWORK AND PROCEDURES ...... 3 6 REVIEW OF APPROACHES TO ENVIRONMENTAL IMPACT ASSESSMENT AND RELATED ENVIRONMENTAL RESEARCH ...... 4 7 REVIEW OF THE ELECTRONIC TEMPLATE FOR COLLATING NATIONAL REPORTS THAT WAS ADOPTED DURING WGEXT 2001 ...... 5 8 FINALISATION OF ICES GUIDELINES FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION ...... 5 9 METHODS TO ASSESS LOCALISED IMPACTS OF AGGREGATE EXTRACTION ON FISHERIES AND THE MEANS TO ADEQUATELY PROTECT HERRING SPAWNING AREAS IN THE VICINITY OF EXTRACTION OPERATIONS...... 6 10 REVIEW OF THE APPLICATION OF RISK ASSESSMENT METHODS AS A TOOL FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION...... 7 11 REVIEW OF THE PROCEDURES FOR DEALING WITH INTERNATIONAL TRANSBOUNDARY ISSUES ARISING FROM THE EXTRACTION OF MARINE AGGREGATE ...... 10 12 ESTABLISHMENT OF A LIST OF RESEARCH/MANAGEMENT/POLICY INITIATIVES FOR MARINE SEDIMENT EXTRACTION ...... 10 12.1 Policy Initiatives ...... 10 12.2 Summary of Environmental Impact Studies and Related Research...... 11 13 REVIEW OF THE RESULTS OF COMPARATIVE TRIALS WITH AGDS AND OTHER ASSOCIATED MAPPING SYSTEMS WITH A VIEW TO DETERMINING THE POTENTIAL FOR SUCH SYSTEMS TO DEFINE AND MAP GEOLOGICAL ENVIRONMENTS AND BIOLOGICAL HABITATS...... 13 14 COMMENCE WORK ON SCOPING THE NECESSARY COVERAGE AND CONTENT OF A NEW WGEXT COOPERATIVE RESEARCH REPORT...... 14 15 RECOMMENDATIONS AND DRAFT COUNCIL RESOLUTIONS...... 15 Draft Resolution 1: Future meeting of WGEXT ...... 15 16 CLOSE OF MEETING AND ADOPTION OF THE REPORT ...... 15 ANNEX 1: LIST OF CONTRIBUTORS TO THE 2001 REPORT ...... 16 ANNEX 2: AGENDA ADOPTED BY WGEXT 2002...... 21 ANNEX 3: REVIEW OF NATIONAL MARINE AGGREGATE EXTRACTION ACTIVITIES...... 25 ANNEX 4: REVIEW OF NATIONAL SEABED RESOURCE MAPPING PROGRAMMES ...... 36 ANNEX 5: REVIEW OF DEVELOPMENTS IN NATIONAL AUTHORISATION AND ADMINISTRATIVE FRAMEWORK AND PROCEDURES ...... 49 ANNEX 6: REVIEW OF APPROACHES TO ENVIRONMENTAL IMPACT ASSESSMENT AND RELATED ENVIRONMENTAL RESEARCH ...... 53 ANNEX 7: DRAFT ICES GUIDELINES FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION... 72 ANNEX 8: COOPERATION BETWEEN ICES (WGEXT) AND OSPAR (BDC SUBGROUP SEABED)...... 79 ANNEX 9: EFFECTS OF SAND AND GRAVEL EXTRACTION ON SENSITIVE MACROBENTHIC SPECIES IN THE SOUTHERN BALTIC SEA...... 99 ANNEX 10: EFFECTS OF EXPLOITATION OF MARINE RESOURCES ON EPIFAUNAL SUSPENSION- FEEDERS ...... 104
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ANNEX 11: ENGLISH SUMMARY OF THE REPORT “BIOLOGICAL SCREENING OF EXTRACTION AREA FOR PEBBLES- AND SAND SUCTION BY DIVE AND SONAR” ...... 108 ANNEX 12: APPARENT INCOMPATIBILITY BETWEEN BIOLOGICAL SETTINGS OF WGEXT GUIDELINES AND CURRENT AGGREGATE DREDGING APPLICATIONS IN THE EASTERN ENGLISH CHANNEL. 118 ANNEX 13: RECOMMENDATIONS AND PROPOSED TERMS OF REFERENCE FOR WGEXT 2003...... 119 @#
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1 INTRODUCTION
The Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem (WGEXT) was welcomed to Boulogne-sur-Mer by Dr Marc Morel, Regional Director of IFREMER, and Henri Dernier, Chef d’Arrondissement du Littoral et des Dragages, Pas-de-Calais, France.
Professor Jon Side, Chair of WGEXT, thanked IFREMER for hosting the meeting and Le Service Maritime des Ports de Boulonge-sur-Mer et de Calais (SMBC) for providing facilities to the Working Group. He provided feedback to the WGEXT members on the 2001 ICES Statutory Meeting, and from the ICES Marine Habitat Committee. He thanked the ICES Secretariat for their support in finalising the publication of the Working Group’s ICES Cooperative Research Report No. 247.
Professor Side thanked all WGEXT members who had provided copies of their reports prior to the meeting.
A number of regular contributors had sent apologies for not attending, though many had also been able to provide reports and would contribute by correspondence. A complete list of contributors is appended as Annex 1 to this report.
2 TERMS OF REFERENCE, OPENING OF MEETING AND ADOPTION OF AGENDA
The terms of reference for the WGEXT meeting were adopted as ICES C. Res. 2001/2E06:
The Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem [WGEXT] (Prof. J. Side, UK) will meet in Boulogne-sur-Mer, France from 9–13 April 2002 as guests of IFREMER in order to: a) review data on marine extraction activities, developments in marine resource mapping, information on changes to the legal regime (and associated environmental impact assessment requirements) governing marine aggregate extraction; b) review scientific programmes and research projects relevant to the assessment of environmental effects of the extraction of marine sediments; c) review the electronic template for collating national reports; d) finalise ICES guidelines for the management of marine sediment extraction, taking into account any comments from ACME; e) continue to examine the methods that might be used to assess localised impacts from aggregate extraction on fisheries, and the means to adequately protect known areas sensitive for fisheries resources, e.g., herring spawning beds in the vicinity of extraction operations; f) review the application of risk assessment methods as a tool for the management of marine sediment extraction; g) review the procedures for dealing with international transboundary issues arising from the extraction of marine aggregates; h) establish a list of research/management/policy initiatives for marine sediment extraction; i) review the results of comparative trials with AGDS and other associated mapping systems with a view to determining the potential for such systems to define and map geological environments and biological habitats; j) commence work on scoping the necessary coverage and content of a planned ICES Cooperative Research Report.
WGEXT will report by 30 April 2002 for the attention of the Marine Habitat and Resource Management Committees and ACME and ACE.
The agenda was adopted. This, and the scientific justification for the terms of reference, appear as Annex 2 to this report.
3 REVIEW OF NATIONAL MARINE AGGREGATE EXTRACTION ACTIVITIES
The following text provides a summary of the review of the national reports on marine extraction activities (TOR items a) and b)). A more detailed record is provided in Annexes 3 to 6. Data were presented by all participating countries with the exception of Norway, Poland and Germany.
Almost all of the material extracted from the seabed is sand and gravel (99 % by volume), with the remainder comprising rock, maerl, shell or shelly sand. The majority is used for construction purposes (including bulk fill),
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although significant amounts are also used for beach replenishment, as explained below and summarised in Table 3.1. The relative proportion of sand and gravel extracted by different countries varies depending on the geology and hydrodynamics of the areas being dredged and the extraction techniques used (e.g., whether the material is screened to select particular size fractions).
Extraction activity in 2001 was fairly similar to that in 2000. The Netherlands continued to extract by far the largest quantities of sand and gravel, with a total of 36.4 Mm3 in 2001. Of this, more than 23 Mm3 was supplied to their construction industry, 13 Mm3 was used for beach replenishment projects, and a further 1.5 Mm3 was exported to Belgium. The UK extracted a total of 13.7 Mm3, of which 9.3 Mm3 was supplied to its construction industry, 0.15 Mm3 was used for beach replenishment, and 4.2 Mm3 was exported (mainly to ports in France, the Netherlands and Belgium). In Denmark, approximately 7.8 Mm3 of sand and gravel was extracted, of which 5.4 Mm3 was used as construction aggregate (mainly bulk fill). A further 2.5 Mm3 of sand was extracted for beach replenishment projects. Sand and gravel extraction from the USA, France, and Belgium in 2001 was 3.5 Mm3, 2.4 Mm3, and 1.9 Mm3, respectively. Canada, Finland, and Sweden reported no extraction activity in 2001. Finland indicated there was an unimplemented permission to extract 8 Mm3 of sand from Helsinki Harbour, and an application had been made to extract 12 Mm3 off Helsinki. The federal Canadian Government will shortly make a decision about whether to continue to develop a framework to permit and control extraction. There has been no extraction of sand and gravel for construction purposes in Sweden since 1992.
As indicated above, much smaller quantities of non-aggregate material are extracted by some countries. France recorded the extraction of 0.47 Mm3 of maerl and shelly sand, and the Netherlands extracted approximately 0.28 Mm3 of shells.
Table 3.1. Summary Table of National Marine Aggregate Extraction Activities.
t n d rted o
he y ishme n d (m³) exp e ple (m³) (m³) (m³) Countr h re EIA ongoing EIA finished EIA initiated extract EIA publis Non-aggregate New legislation ac Aggregate Aggregate extracted Be Maps published in 2001 Belgium 1,911,000 0 0 0 No No Yes Yes No No Canada 0 0 0 0 — — — — — — Denmark 7,862,000 0 0 2,460,000 Yes No Yes — Yes Yes Finland 0 0 0 0 — — — — — — France 2,427,000 470,000 0 0 Yes No Yes — — — Germany No data No data No data No data — — — — — — Ireland 0 No data 0 No data No No No * No No Netherlands 36,400,000 282,000 1,500,000 13,140,000 Yes — — — Yes Yes Norway No data No data No data No data — — — — — — Poland No data No data No data No data — — — — — — Sweden 0 0 0 0 Yes No No — No No United Kingdom 13,712,000 0 4,212,500 148,000 No No Yes Yes No No United States 3,509,000 0 0 2,209,000 Yes — — — — —
*a strategic study of aggregate extraction is being undertaken.
4 REVIEW OF NATIONAL SEABED RESOURCE MAPPING PROGRAMMES
Seabed resource mapping programmes have been (or are being) undertaken by most participating countries. Some countries, such as the UK, have already published maps of the seabed within their territorial waters at the reconnaissance level, and for some areas at a more detailed resource assessment level, and have no current
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programmes. In a number of countries, more thematic mapping programmes (e.g., habitat mapping) are also being undertaken.
The national reports (reproduced in Annex 4) vary in their content and detail. Some provide information on completed and ongoing programmes, while others report activity during 2001 only. The summary below focuses only on mapping activity and the related publication of maps for 2001.
Canada has an active mapping programme concentrating, at present, in the south. Studies include habitat mapping, assessment of deep-water slope areas where potential exists for hydrocarbon development, seabed engineering hazard classification, and in newly declared marine protected areas for habitat and terrain characterisation. A proposal for a Canadian regional systematic multibeam mapping project (“SeaMap”) is awaiting approval. This would produce multibeam bathymetric, backscatter and slope assessments as well as geological interpretative products of sediment distribution, habitat, seabed dynamics and hazards. In preparation for the project, a study was undertaken in 2001 to develop standards and a template for map production.
Mapping continues in Denmark, and last year was concentrated in the North Sea, Kattegat and the Baltic. A summary is given in the Annex of surface sediment map and seismic survey coverage. The results of a number of projects will be published shortly, including a surface sediment map of the Jutland Bank.
Finland is conducting a survey of late-Quaternary deposits on the seabed using acoustic and seismic methods to acquire data on the distribution and thickness of sediments, and to provide information on stratigraphy, mineralogy and geochemistry of deposits. New methods of sounding, sampling and data processing are also being developed and tested.
In France, the Marine Geosciences Department of IFREMER has been undertaking seabed mapping since 2000. This includes side-scan sonar, multibeam bathymetry, echo-sounder, high-resolution seismics, grabs, corers and video techniques. A morphological map of the Gulf of Lyon (Mediterranean) was published in 2001.
The Netherlands reported programmes of reconnaissance surveys at 1:250,000, and geology and resource mapping at 1:100,000 (see Annex 4). Six sheets of the 1:250,000 series have been published since 1984. A seventh sheet is in preparation. Only two sheets at 1:100,000 have been printed. It is proposed that all sheets will eventually be available in digital format. Survey methods employed include use of the Hamon grab, electric and hydraulic vibrocorers, echo- sounders, multibeam bathymetry, side-scan sonar, sub-bottom profilers and sleeve guns. A research programme, started in 2000, is looking at the relationship between seabed morphodynamics, sediment transport and ecology. Results are expected in 2002. Geochemical distribution graphs of surface sediments are being prepared for the entire Dutch sector. This is to provide reliable information on natural background levels allowing assessment of the influence of human activity.
Sweden continued its mapping programme, with mapping at 1:50,000 and 1:100,000 last year of the Norrköping area and Lake Malaren. Reconnaissance mapping of the whole of the Swedish EEZ at 1:500,000 started in 2000 and is continuing. The programme for 2002 involves mapping off Gavle (1:100,000) and the Swedish EEZ of the southern Bothnian Sea (1:500,000).
The UK has continued its work on seabed characterisation in the inshore zone (to 12 n.m.), and has looked at the potential use of geological data for habitat mapping.
The USA is undertaking mapping to identify sand resources for beach nourishment and to identify benthic habitats. A number of reports and papers covering geological and habitat mapping were published and are listed in Annex 4.
5 REVIEW OF DEVELOPMENTS IN NATIONAL AUTHORISATION AND ADMINISTRATIVE FRAMEWORK AND PROCEDURES
All countries that reported in 2001 indicated that some form of administrative framework was already in place to authorise dredging activities. These vary from general legislation, covering a range of activities in the maritime area (e.g., the Oceans Act 1997 in Canada), to more specific legislation dealing with dredging activities (e.g., the Raw Materials Act 1997 in Denmark), to the Government View Procedure currently operating in the UK. No new legislation was reported, although the UK indicated that preparation of Regulations to introduce a statutory system of control was in progress. Further details are provided in Annex 5.
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6 REVIEW OF APPROACHES TO ENVIRONMENTAL IMPACT ASSESSMENT AND RELATED ENVIRONMENTAL RESEARCH
The national reports (see Annex 6) demonstrate a great deal of activity on the assessment of the effects of dredging activities. This includes individual Environmental Impact Assessments (EIAs) associated with specific applications for new dredging areas, the results of monitoring the effects of ongoing dredging, a strategic assessment study in Ireland, and any relevant research projects.
Belgium indicated that changes to their legislation in 1999 meant that an EIA is required for every new application, although legislation to enforce this requirement is in preparation.
There is no aggregate dredging activity in Canada at present, as recorded above. However, studies have been undertaken of the effects of disposal of dredged sediments and the effects of seabed trawling and clam dredging on seabed habitats. A study to define and map essential fish habitats on the Scotian Shelf was started in 2001. A pilot study has been completed. Another pilot study was undertaken in 2001, which used a QTC seabed acoustic characterisation system with high-resolution fish detection systems, to evaluate, in part, the ability of QTC to characterise and differentiate the variety of benthic habitats in comparison with high-resolution side-scan sonar data. The evaluation of data is ongoing.
Denmark reported on a study of the effect of extracting 8 Mm3 of sand from the Harbour of Århus, and the preparation and publication in 2001 of a new EIA to dredge a further 7 Mm3 from the harbour. A number of earlier EIAs are also recorded. Denmark also reported on a number of research projects, including one on the impact of dredge spill on benthos and a study to evaluate different seismic and diver techniques to develop reliable low-cost screening methods for identification of the most important benthic flora and fauna communities. The Forest and Nature Agency and the Coastal Protection Agency have also initiated a monitoring programme off the West Coast of Jutland to study the effects of dredging for beach protection.
France reported on a research programme aimed at developing a better understanding of the impact of sandpits on seabed morphology in shallow waters. The aim is also to develop a methodological guide to define a number of indicators to be investigated as part of an environmental impact study, along with accepted values for these indicators. An update is also given of the results of last year’s monitoring at the Dieppe Case Study site (which has been monitored since 1980), including initial findings. A further study initiated in 2002 seeks to assess the impact of marine aggregate extraction, and includes monitoring of fish in the extraction and surrounding areas, the assessment of trophic relationships between benthic and demersal fish species and benthic preys, and assessment of rehabilitation processes within the former extraction site.
The Netherlands reported on the fourth and final year’s monitoring of the recovery of the benthic community on an infilled borrow pit located in 7 m of water. It was concluded that, within such a dynamic environment, the sediment recovers within one year, but it takes four years to have complete recovery of the benthic community. Another study (PUTMOR) is looking at the effects of a large extraction pit on surrounding areas. Measurements are being taken of bathymetry, flow velocities, water levels, temperature, conductivity, turbidity, oxygen content and seabed sediments. A study to improve knowledge on the relationship between different natural processes affecting benthic life was started in 2000 and continues. A study to integrate present knowledge and site-specific information in order to understand and predict the possible environmental impacts of different human activities started in 2001. Ecotope maps will be produced at a scale applicable to detailed EIAs. Ongoing EIAs are reported for areas off the coast of South-Holland, the Cleaverbank and off the coast of Zeeland.
The UK provided updated information on 1) the Southern North Sea Transport Study, which is due to finish in July/August 2002, 2) the MarLIN project which seeks to identify sources of marine biological data and to assess, grade and use that data to identify distributions of biotopes and species, 3) a study on the potential for cumulative environmental effects arising from marine aggregate extraction which is due for completion in April 2002, 4) the assessment of the rehabilitation of the seabed following marine aggregate dredging, and 5) progress with the procedural guidelines for the conduct of benthic studies at aggregate dredging sites. A number of new studies were reported, including one to develop and test hypotheses on the impact of climate change on rocky intertidal animals and plants, a scoping study to assess the applicability of a development plan for the seabed, a study assessing the utility of seabed habitat mapping for the monitoring and management of several human activities that disturb the seabed (including aggregate dredging), and a study examining the direct and indirect biological impacts of aggregate extraction in the Southern North Sea.
The USA is undertaking research to produce a predictive desktop package that links the various phases of sediment plumes that arise from aggregate dredging.
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Two projects funded by the European Union were reported. One, SANDPIT, seeks to assess the physical implications of large-scale marine sand extraction and to produce a handbook synthesising scientific results and practical guidelines for sandpits, and to produce publications on sand transport in coastal areas. The second, EUMARSAND, seeks to establish a European research trainee network to develop integrated strategies for the prospecting and extraction of marine aggregates, including assessment of the physical and biological impacts of dredging activities. A third EU- funded research project, SUMARE, has reported previously at WGEXT 2001 and will provide a further report of progress next year.
7 REVIEW OF THE ELECTRONIC TEMPLATE FOR COLLATING NATIONAL REPORTS THAT WAS ADOPTED DURING WGEXT 2001
WGEXT reviewed a draft form for submitting national data by regions through the Internet. The submission form will be trialled in reporting data to WGEXT. It consists of an HTML form, which can be filled out and then sent as an e- mail message to the member(s) managing the database.
WGEXT discussed whether it was necessary to include reports distinguishing between aggregate from navigational dredging and commercial extraction. Members decided that it was premature to try to distinguish between the two categories of information in the database as several member countries did not provide their data in such a form.
Figure 7.1. WGEXT electronic template for submission of national reports.
8 FINALISATION OF ICES GUIDELINES FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION
The draft guidance for the management of marine sediment extraction, which was drafted last year, had circulated widely and comments had been received from a number of authorities including OSPAR. Following discussions on these comments at WGEXT, relevant changes were incorporated into the document, and WGEXT agreed that these should represent the final guidelines, even though WGEXT would continue to examine risk assessment and risk management approaches in the context of the management of extraction activities. Previously published work by ICES (ICES, 1989, 1992, 1993), and the more recent guidance by HELCOM (HELCOM recommendation 19/1), were taken
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into account in preparing these draft guidelines. The new finalised guidelines are appended to this report as Annex 7, and are designed to be an update to both the previous Code of Practice and guidelines on EIA.
References
Annex 7 (to this report) Guidelines for the Management of Marine Sediment Extraction.
ICES. 1989. Code of Practice for the Commercial Extraction of Marine Sediments, pp. 48–50 in ICES (1992), see below.
ICES. 1992. Report of the ICES Working Group on the Effects of Extraction of Marine Sediments on Fisheries Cooperative Research Report, 182, 78pp.
ICES. 1993. Draft Guidance on Environmental Assessment for Marine Aggregates Dredging Proposals, pp. 18–27 in the Report of the Working Group on the Effects of Extraction of Marine Sediments on Fisheries, May 1993, ICES CM 1993/E:7.
9 METHODS TO ASSESS LOCALISED IMPACTS OF AGGREGATE EXTRACTION ON FISHERIES AND THE MEANS TO ADEQUATELY PROTECT HERRING SPAWNING AREAS IN THE VICINITY OF EXTRACTION OPERATIONS
The results of the studies being undertaken in Ireland on herring spawning grounds were not yet available for reporting back to WGEXT. It was agreed to check the status of this work with a view to further discussions next year.
A presentation to the Working Group by Michel Lemoine, based on work by Michel and Frédéric Courbet at IFREMER, showed a significant lack of correspondence between generalised thematic maps of fish spawning grounds in the English Channel, particularly for plaice. Observing the importance placed by WGEXT in its guidelines and work generally on the protection of biologically sensitive areas and in particular for spawning fishes, the authors concluded that such information conflicts required careful examination, particularly where the assessments of specific projects were making use of such maps. The presentation suggested that:
• a large uncertainty exists in the outlines of spawning areas in such thematic maps, and that it was these uncertainties that had resulted in the use of presence/absence of spawning grounds instead of a measure of intensity as mapping parameters; • a large number of aggregate extraction applications overlapped biologically sensitive areas such as spawning grounds; • such sensitive areas in any event cover large areas of the seabed and hence avoiding such overlaps is a practical impossibility.
Furthermore, it is unlikely that new studies could rapidly resolve such uncertainties or provide significant new information, and thus the assessment of these applications would have to take into account the uncertainties and make judgements of acceptable risk. (A summary of the presentation is attached as Annex 12.)
Further discussion led to the following observations.
There was some doubt that spawning grounds could be precisely located in space and time, or in terms of the nature of the sediment and behaviour of the fish stock. There is often a suggestion that there is a strong relationship between stocks of herring and localised spawning grounds. The number of spawning grounds for herring in the North Sea seems to have reduced in recent years and had showed a great deal of variability. WGEXT was uncertain of the usefulness of any project that tried to pinpoint all actual spawning grounds from recent data, though obviously specific grounds were identifiable in this way (for example, herring egg surveys have been used to identify protected areas for herring spawning in the Baltic). It was suggested that, instead, it would be desirable to develop a clearer picture of potential spawning grounds, but using information on known locations (past and present) and by looking to correspondence with other physical parameters such as substrate. In the Baltic Sea, there appears to be a correlation with oxygen conditions; elsewhere, current velocity ranges may have a bearing. One suggestion was to identify areas where herring were unlikely to spawn.
In France, the concept of potential nursery grounds has been used to identify corresponding areas of biological sensitivity using actual survey data, bathymetry and sedimentology, and outline boundaries of potential coastal nursery
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areas have been delineated in this way for several species such as plaice, sole, dab, bass, etc. It has also been shown that areas of successful scallop settlement appear to have a very specific granulometry.
After further consideration, WGEXT agreed that it would be useful to attempt the following (commencing work inter- sessionally and refining and discussing the outcomes at its next meeting):
Employ a risk assessment approach (similar to that mentioned in Section 10, below, on risk management being developed by Stuart Rogers at CEFAS) taking 20 or so species and for each separating life histories into adults (feeding grounds), migrations, spawning grounds, juvenile drift and nursery grounds. For each of these, the risk matrix would use “potential sensitivity” of the species at this stage in its life history and “actual vulnerability” to dredging operations. The selection of species would be based on the target list discussed by WGEXT at its meeting in 1998, and on the detailed study undertaken on the English Channel in 1993 by IFREMER/MAFF experts to identify the biogeographic distribution of stocks for 25 species. Some attempt to undertake a deterministic calculation of the likely magnitude of the direct and indirect effects of dredging activity at each stage on the subsequent fish stock was considered worthwhile, and while it would require caution it may assist in developing a better appreciation of the scale of any likely effect, and the identification of the nature of effects which are essential to risk mitigation.
It was stressed that seabed alteration as a result of dredging activity of itself will not result in any proportionate reduction. Moreover, the replacement of certain seabed biotopes by others may result in more productive feeding grounds for other species—a picture that seems to be emerging from some of the work in France. It would be interesting to see whether this idea could be developed further. Work being undertaken by WGECO was suggesting that, in general, the seabed disturbance caused by beam trawling was greater than that resulting from dredging activity, though this work had ignored plume effects.
It was agreed that a case study of plaice spawning grounds in the English Channel should be attempted, drawing on the literature of surveys conducted in this area and any recent data that could be made available. The purpose is simply to examine the extent to which this knowledge is captured in the thematic maps, and the variability between such maps. Some comparison might then be undertaken with sediment and bed load transport maps for these areas. It was reported that RIVO was considering a similar exercise for flatfish nursery grounds in the Wadden Sea area.
It was agreed that this particular aspect of the potential effects of dredging activities should be a major theme in the planned ICES Cooperative Research Report.
10 REVIEW OF THE APPLICATION OF RISK ASSESSMENT METHODS AS A TOOL FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION
WGEXT reviewed risk assessment methods drawing the following distinctions in terminology:
Risk analysis - the analysis of data and information for determining levels of risk;
Risk assessment - the acceptability of risk from an activity and judgements on mitigation, etc.;
Risk management - the framework under which risk assessment is conducted and mitigation measures and targets are set.
Risk assessment developed originally as a technique for examining the risk of human injury from accidental events. Following the war, it was widely used in NASA and, more recently, has been adopted by the chemical, oil and related processing industries.
In the context of accidental events. risk is a measure of both the frequency (or likelihood) of an undesired event and the consequences should it occur. Risk assessment is the determination of whether this level of risk is acceptable or whether risk reduction should be sought. Risk reduction can be achieved by reducing the likelihood of an undesirable event, or by reducing the consequences should it occur, or both.
A number of industrial activities now apply risk assessment techniques to the evaluation of environmental rather than human risk. Among the best-known examples of this is the use of environmental risk assessment in the examination of risk of an oil spill. Here, another form of endpoint is required for the consequence analysis and, rather than human injury, oil impinging the coastline or another vulnerable environmental receptor such as seabirds at sea, are often adopted.
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While in many countries risk analyses of human safety can be assessed against known benchmarks of acceptability, it is rather more problematic when judgements of the acceptability of environmental risk are required. Most discussion on risk assessment, however, with regard to routine or planned, rather than accidental, events is concerned with reducing uncertainties, arising from lack of knowledge, in the environmental impact assessment.
The Working Group observed that there are two types of uncertainty:
• reducible uncertainty (where we know that we don’t know); • irreducible uncertainty (where we do not know that we don’t know).
As an illustration of the latter, an EIA conducted in the early 1970s notes that the release of halon is unlikely to have environmental effects and that none were known. Following this, the mechanism for CFC interaction with the ozone layer was published and finally the British Antarctic Survey discovered a hole in the ozone layer. At the time of the EIA, this uncertainty was irreducible. There is little that risk management or risk assessment can do to assist decision- makers where irreducible uncertainty is concerned.
Reducible uncertainty arises from lack of knowledge of ecosystems and industrial systems and also where knowledge of both of these is combined to provide predictions of impact and effects (or impact hypothesis).
Equally at the present time there remains uncertainty regarding the acceptance criteria that would be applied in determining whether the impacts (and uncertainties associated with these) are acceptable.
The Working Group suggested that one approach to this is to see EcoQOs as a means by which the acceptability of impacts and risks can be gauged. A general approach to the assessment and management of risk in relation to marine aggregate extraction projects was elaborated following further discussion and this is reproduced diagrammatically in Figure 10.1.
The general principles are as follows:
1) The approach distinguishes between accidental events and impacts (where a conventional environmental risk assessment is used, e.g., for oil spills) and planned events and impacts arising from the project (where an EIA would be used to attempt the prediction of these). 2) Within the EIA process, the uncertainties associated with the predictions of effects and uncertainties arising from lack of knowledge of:
i) the ecosystem; ii) the marine aggregate extraction operation (industry system); and iii) the compounding of these uncertainties in making predictions of effects and impacts.
WGEXT emphasised the importance of uncertainties that arise, in particular, in relation to spatial and temporal scales and that in many cases the range and boundaries of uncertainty could at least be estimated.
3) Importantly in the assessment of impacts and uncertainties, one approach already adopted is that of setting acceptable limits. This approach is evident in the management of the Øresund link project where, for example, while the actual amounts of fines that might arise from the dredging operation were not known, a target was imposed which they could not exceed.
The Working Group also examined risk matrix approaches, such as the one adopted by Stuart Rogers at CEFAS for risk assessment of uncertainties concerning impacts of aggregate extraction on fisheries.
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It was agreed that there were many approaches to risk assessment at this stage, and that WGEXT would seek further examples to continue its discussions at its next meeting, and for inclusion in the planned ICES Cooperative Research Report.
Figure 10.1. Risk Assessment Framework considered for further discussion.
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11 REVIEW OF THE PROCEDURES FOR DEALING WITH INTERNATIONAL TRANSBOUNDARY ISSUES ARISING FROM THE EXTRACTION OF MARINE AGGREGATE
The Convention on Environmental Impact Assessment in a Transboundary Context (Espoo, 1991) sets out the process for notification, consultation, and assessment of projects that may have an environmental impact in a transboundary context. The Convention defines transboundary impacts as “…any impact, not exclusively of a global nature, within an area under the jurisdiction of a Party caused by a proposed activity the physical origin of which is situated wholly or in part within the area under jurisdiction of another Party.”
Following developments in the practice of EIA, it is now customary in many countries to include a scoping stage early in the EIA process. This enables the identification of significant issues associated with the proposed development, which then must be addressed in the EIA.
This stage usually involves extensive informal exchanges with relevant stakeholders which, at the present time, are not specifically provided for by the Espoo Convention.
Thus, in addition to the requirements of the Convention, many States would now seek to identify practical issues (and the relevant stakeholders) at an early stage to inform the EIA process. This will often entail formal and informal consultation, at both an administrative (regulatory/political) and scientific level. It may also be useful for the developer to be involved in the early stages of communication directly, particularly where it is the developer who is responsible for preparing EIA documents.
In these circumstances, the competent authorities in all of the States concerned should be encouraged to reach agreement on how these requirements can be met in practice. WGEXT offers the following observations on some matters that such agreement should seek to clarify, in the context of marine aggregate extraction projects:
i. Whether it is necessary to contact – the Espoo Convention states that the Competent Authority in the country with jurisdiction over the activity is required to consider whether it is likely to cause a “…significant adverse transboundary impact.” If a proposed extraction activity could have an impact on the environment of an adjacent country, then consultation is encouraged. ii. When to contact – the Espoo Convention provides for the notification of an adjacent Party where a project/development may potentially have transboundary implications, and formally consult on the completed EIA. There is a benefit in engaging in consultation with adjacent Parties as early as possible, and certainly at the scoping stage of an EIA, to ensure that all relevant issues are identified, and therefore adequately addressed in the EIA process. iii. Who to contact – the early identification of the point of contact in the Competent Authority is important to ensure that unnecessary delays are avoided, and appropriate information/views (administrative and scientific) can be exchanged. iv. Who carries out the consultation/contact – the Competent Authority is responsible for the formal transboundary contact and consultation. Additionally, it may be appropriate for informal exchanges concerning scientific aspects, particularly associated with the scoping stage of the EIA, to be agreed by the competent authorities. v. What to do on receipt – the Competent Authority in the adjacent country is encouraged to circulate information associated with the transboundary project development to appropriate stakeholders, and coordinate further exchanges. vi. Timescale – Appropriate and realistic timescales for formal responses are very important if the consultation process is to be effective. Timescales for responding should be agreed between the Competent Authorities involved, taking into account differences in the level of scientific and policy understanding that may exist between them.
WGEXT would encourage Competent International Authorities such as OSPAR and HELCOM to consider these matters further.
12 ESTABLISHMENT OF A LIST OF RESEARCH/MANAGEMENT/POLICY INITIATIVES FOR MARINE SEDIMENT EXTRACTION
12.1 Policy Initiatives
At the present time, there are two overarching policy issues that have the potential to significantly influence marine aggregate extraction in Northwest Europe:
10 2002 WGEXT Report
• Annex 5 of the OSPAR Convention; • Spatial planning.
Annex 5 expanded the OSPAR Convention’s horizons to encompass an ecosystem approach to the management of the Convention Area and developed the general obligations given in Article 1(2)(a) of the Convention. The strategy for the implementation of Annex 5 requires the assessment of a number of human activities, including “sand and gravel dredging”, that are likely to have an actual or potential adverse effect on species and habitats or on ecological processes. The OSPAR Commission is then required to draw up programmes and measures for the control of those human activities identified by the application of the criteria in Appendix 3 as requiring control. Sand and gravel extraction is currently under review by OSPAR based on information from ICES WGEXT.
The 5th North Sea Conference recently requested OSPAR to develop approaches to spatial planning in the North Sea and the wider OSPAR maritime area. It is too early to tell what approaches will be developed, but it is likely that all human activities in the OSPAR area could be influenced by this initiative. In addition, the EU announced an Integrated Coastal Zone Management initiative in 2001.
12.2 Summary of Environmental Impact Studies and Related Research
Table 12.2.1. Summary Table of Environmental Impact Studies and Related Research.
Project Country Description Start Contact Reported Bay of Fundy Canada Impact of dredge disposal in the Bay of Fundy Northumberland Strait Canada Evaluation of the disposal and attempted creation of new marine habitat from dredged material Canada Effects of seabed trawling and clam dredging on seabed habitat Eastern Scotian Shelf Canada Definition and mapping of essential 2001 fish habitat on the Scotian Shelf The Harbour of Århus Denmark EIA for dredging of up to 7 mio. m³ of 2001 P.E. Nielsen Y sand fill for a further enlargement of the harbour Stigsnæs Denmark EIA for the construction of a Container 2000 P.E. Nielsen Y Terminal Hub near Stigsnæs, Western Zealand North Sea Denmark EIA for 4 new dredging areas in the 2001 P.E. Nielsen Y North Sea to be used for dredging of sand for beach nourishment North Sea Denmark EIA for both onshore and nearshore 2001 P.E. Nielsen Y nourishment.
Horns Rev Windfarm Denmark EIA for dredging operations necessary P.E. Nielsen for the construction of marine windfarms
Low cost screening of Denmark Investigation of different methods for 2000 P.E. Nielsen Y biological interests screening of biological interests in proposed dredging areas Dredger Emissions Denmark Study of the energy consumption and P.E. Nielsen Y emissions from dredging and transport Statistics Denmark Study on the use of statistical analyses P.E. Nielsen Y in environmental monitoring of dredging spill
2002 WGEXT Report 11
Project Country Description Start Contact Reported Effects of exploitation Denmark Effects of suspended and settled 2001 P.E. Nielsen Y of marine resources on material on selected benthic epifaunal suspension- suspension-feeders feeders France The impact of sandpits on the bottom 2001 C. Augris morphology in shallow water REBENT Study France Relation between macrobenthos and oil 2001 B.Guillaumont Y pollution and long-term climate change Dieppe Case Study France Impact of extraction, oversanding and 2001 M. Desprez 2002 recolonisation Impact of marine France Impacts on fish and benthos in 2002 M. Desprez aggregate extraction extraction sites and surrounding areas Punaise*3 Project Netherlands Recovery of the benthic community in 2001 J. van Dalfsen Y an area of a former temporary borrow pit Aggregate extraction Netherlands Environmental impact of the extraction 1998 A. Stolk South Holland of a maximum of 40 million tonnes of aggregate sand from a depth of 5 to 30 metres below the seabed Cleaver Bank Netherlands EIA for aggregate sand and gravel from 2001 A. Stolk the Cleaver Bank Area (DCS) Westerschelde Netherlands EIA for fill sand off the coast of 2001 A. Stolk Container Terminal Zeeland PUTMOR Netherlands Study of physical parameters in an A. Stolk Y extraction pit in order to qualify and to quantify the morphological and ecological effects of sand extraction pits Archaeological and Netherlands Production of maps with archaeological 2001 A. Stolk Y cultural heritage cultural heritage values and geomorphological and geological values Kust*2005 Zeebodem Netherlands Impact of (large-scale) extraction of 2001 A. Stolk sand in relation to the licence conditions SANDPIT Netherlands Study of the (physical) implications in A. Stolk time and space of large-scale extraction of marine sand FLYLAND Netherlands 4-year study on ecological and 1999 H. Welleman Y morphological effects of a possible new airport built on a sea island BEAST Netherlands Integration of knowledge and site- 2001 J. van Dalfsen specific information in order to understand and predict the possible environmental impacts of different human activities Ecomorphodynamics Netherlands Study of the relationship between 2000 J. van Dalfsen different natural processes affecting benthic life Southern North Sea United Sediment transport in the southern T. Murray Summer Transport Study Phase Kingdom North Sea 2002 2 Marine Life United Identification of sources of marine T. Murray Information Network Kingdom biological data (MarLIN)
12 2002 WGEXT Report
Project Country Description Start Contact Reported Marine Biodiversity United Synthesis of existing long-term data on and Climate Change Kingdom temperature-sensitive, readily observed (MarClim) intertidal climate indicator species United Investigation of the Potential for Kingdom Cumulative Environmental Effects Arising from Marine Aggregate Extraction United Assessment of rehabilitation of the Kingdom seabed following marine aggregate dredging United Procedural guidelines for the conduct Kingdom of benthic studies at aggregate dredging sites United Development Plan for Marine Kingdom Aggregate Dredging North Nab Research United Biological and physical impact of Kingdom marine aggregate extraction Area 408 United Examining the direct and indirect 2000 M. Russel Kingdom biological impacts of marine aggregate (BMAPA) extraction at an isolated production licence in the Southern North Sea Project A1033 United Role of seabed mapping techniques in Kingdom environmental monitoring and management Sediment Plume United States Plume modelling programme to predict 2001 M. Russel Modelling of America various phases of plumes that arise (BMAPA) from sand and aggregate dredging EUMARSAND EC Integrated strategies for the prospecting 2002 A. Stolk and extraction of marine aggregates, including the environmental effects
13 REVIEW OF THE RESULTS OF COMPARATIVE TRIALS WITH AGDS AND OTHER ASSOCIATED MAPPING SYSTEMS WITH A VIEW TO DETERMINING THE POTENTIAL FOR SUCH SYSTEMS TO DEFINE AND MAP GEOLOGICAL ENVIRONMENTS AND BIOLOGICAL HABITATS
WGEXT discussed the use of AGDS as a tool for mapping seabed characteristics taking into account:
CEFAS Technical Report No. 114 (2001) “Mapping of gravel biotopes and an examination of the factors controlling the distribution, type and diversity of their biological communities”.
CEFAS/University of Newcastle Report (2001) “Ensuring continuity in the development of broad-scale mapping methodology - direct comparison of RoxAnn and QTC-VIEW technologies”.
The information from Canada in the final paragraph of the Canadian section in Annex 6 of this report.
The Group concluded that the points made in Section 9.2.1–9.2.4 of the 2001 WGEXT report were still valid. They also endorsed the conclusion in CEFAS Technical Report No. 114 that “Acoustic methods should not be used in isolation as a tool for the prediction of seabed traits (biological and physical) and ground-truthing methods should always be used to confirm interpretations”.
WGEXT approved the final text of a manuscript to be submitted to the ICES Journal of Marine Science based on the studies undertaken by the Working Group in recent years on this subject. The Chair agreed to oversee submission to the journal and keep members informed of its progress.
2002 WGEXT Report 13
14 COMMENCE WORK ON SCOPING THE NECESSARY COVERAGE AND CONTENT OF A NEW WGEXT ICES COOPERATIVE RESEARCH REPORT
WGEXT discussed the scope proposed for a new ICES Cooperative Research Report. It was emphasised that the new report should, inter alia, reflect any progress made, and research undertaken, that provided new knowledge and understanding on the research recommendations made in the previous reports (ICES Cooperative Research Report Nos. 182 and 247). It was also emphasised that decisions on extraction projects, while based on the best possible knowledge and understanding, often relied on imperfect and incomplete knowledge of the marine environment and its dynamics. Contributions were therefore encouraged which would examine the implications of this more explicitly, in the new Report, adopting for example some of the ideas emerging during the Working Group’s discussions on risk assessment and management.
The following structure was adopted as the basis for progressing the ICES Cooperative Research Report, and the names identified against each theme record those indicating that they would give further thought to the detail of the material content to be included and reviewed, and coordinate the input from other WGEXT members and experts as required. It was agreed that discussion on these and the development of outline text should form a substantial part of the next WGEXT annual meeting.
Introduction
1) Aggregate Extraction • dredging operations and techniques (e.g., screening), with a focus on recent and forthcoming developments in these [Mark Russell] • resource management by the operators [Mark Russell] • extraction amounts with a focus on trends and future demand [Hans Hillewaert]
2) Environmental Research • to include update on mapping programmes (with details of maps in Appendix) [Ingemar Cato] • to include review of the adequacy/reliability of environmental knowledge and understanding applied to the evaluation of the effects of extraction activities [Henny Welleman and Jochen Christian Krause] • to include assessment of gaps in this which may be addressed by further research [Henny Welleman and Jochen Christian Krause]
3) Effects • overall update on progress made in the evaluation of ecosystem effects [Siân Boyd and Chris Vivian] • examination of the special implications for vulnerable/sensitive and rare systems (e.g., biotopes) and species [Michel Desprez] • examination/review of the effects on fishes, fisheries, fishers and fishing activities [Jon Side and Michel Lemoine]
4) Management [Chris Vivian] • detail of regulating regime, etc., to appear only as an Appendix • reviewing especially risk assessment and risk management approaches • reviewing especially developments in EIA approaches and monitoring • (ICES Guidelines and other relevant material to be included in Appendices)
5) Conclusions
Provisional Timetable
WGEXT 2003 – Outline of substance and structure for each contribution. WGEXT 2004 – Production of draft Report. WGEXT 2005 – Agree and release final Report for publication.
14 2002 WGEXT Report
15 RECOMMENDATIONS AND DRAFT COUNCIL RESOLUTIONS
Draft Resolution 1: Future meeting of WGEXT
The Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem [WGEXT] (Chair: Prof. J. Side, UK) will meet in Oostende, Belgium from 1–5 April 2003 as guests of MUMM and DvZ in order to: a) review data on marine extraction activities, developments in marine resource mapping, information on changes to the legal regime (and associated environmental impact assessment requirements) governing marine aggregate extraction; b) review scientific programmes and research projects relevant to the assessment of environmental effects of the extraction of marine sediments; c) review the template and electronic submission procedures for recording and collating national reports; d) receive feedback on the use of the new ICES Guidelines for the Management of Marine Sediment Extraction, and consider whether further specific guidance is required in special cases of extraction activities where unusual environmental conditions prevail, discussing also any feedback received on observations for procedures dealing with transboundary issues; e) continue work on the planned ICES Cooperative Research Report, and in particular to this end: (i) provide a review of the quantity, quality, location, and uses of marine sediments extracted annually since 1980; (ii) continue to review the application of risk assessment methods as a tool for the management of marine sediment extraction; (iii) continue to assess localised impacts from aggregate extraction on fisheries, and the means to adequately protect known areas sensitive for fisheries resources, e.g., herring spawning beds in the vicinity of extraction operations, particularly in the light of methods for determining impacts and the use of risk assessment; (iv) review progress made by contributors in scoping the detail of the content of sections of the report.
As requested by the ICES Secretariat, the full resolution on terms of reference and the accompanying scientific justification, explanations and administrative details are attached as the final annex to this report, Annex 13.
16 CLOSE OF MEETING AND ADOPTION OF THE REPORT
Professor Side thanked those attending, and those who had worked intersessionally on various items. He thanked in particular Sarah Lindop for agreeing to take over the reins as rapporteur from Sian Boyd at such short notice, and Hans Hillewaert for his continuous support of the electronic submission procedures and related web infrastructure. WGEXT thanked IFREMER for hosting the meeting, and their hard work in support of WGEXT activities during the meeting. WGEXT adopted its report of the meeting.
2002 WGEXT Report 15
ANNEX 1: LIST OF CONTRIBUTORS TO THE 2002 REPORT
Dr Claude Augris Département Géosciences Marines (by Correspondence) Technopôle Brest-Iroise P 70 29280 Plouzané France TEL: +33 (0) 2 98 22 42 42 FAX: +33 (0) 2 98 22 45 70 E-mail: [email protected]
Prof. Henry Bokuniewicz State University of New York (by Correspondence) Stony Brook New York 11794–5000 USA TEL + 1 516 632 8701 FAX + 1 516 632 8820
Dr Sian Boyd CEFAS Burnham Laboratory (by Correspondence) Remembrance Avenue Burnham-on-Crouch Essex CMO 8HA United Kingdom TEL: + 44 1621 787200/245 FAX: + 44 1621 784989 E-mail: [email protected]
Ms. Sarah Lindop CEFAS Burnham Laboratory (Rapporteur) Remembrance Avenue Burnham-on-Crouch Essex CMO 8HA United Kingdom TEL: + 44 1621 787200/262 FAX: + 44 1621 784989 E-mail: [email protected]
André Carpentier IFREMER Laboratoire Ressources Halieutiques 150 quai Gambetta 62200 Boulogne-Sur-Mer France TEL: + 33 (0) 3 2199 5609 FAX: + 33 (0) 3 2199 5601 E-mail: [email protected]
Dr Ingemar Cato Geological Survey of Sweden Division of Marine Geology Box 670 S-751 28 Uppsala Sweden TEL: + 46 18 179 188 FAX: + 46 18 179 420/179 210 E-mail: [email protected]
16 2002 WGEXT Report
Mr Jan van Dalfsen TNO Environment, Energy and Process Innovation Department for Ecological Risk Studies Ambachtsweg 8a P.O. Box 57 1700 AB Den Helder The Netherlands TEL: + 31 223 638838 FAX: + 31 223 63 0607 E-mail: [email protected]
Dr Michel Desprez GEMEL Stn d'Etudes en Baie de Somme Quai Jeanne d'Arc 80230 St Valery-s/Somme France TEL: + 33 322 26 85 25 FAX: + 33 322 26 87 74 E-mail: [email protected]
Mr Chris Dijkshoorn Ministry of Transport, Public Works and Water Management North Sea Directorate PO Box 5807 2280 HV Rijswijk The Netherlands TEL: + 31 70 3366642 FAX: + 31 70 3900691 and 31 70 3194238 E-mail: [email protected]
Dr Gordon Fader Geological Survey of Canada (by Correspondence) Bedford Institute of Oceanography PO Box 1006 Dartmouth N.S. B2Y 4A2 Canada TEL: + 1 902 426 2159 FAX + 1 903 426 4104 E-mail: [email protected]
Dr S. J. de Groot Aquaculture Research PO Box 97 2080 AB Santpoort – Zuid The Netherlands TEL: + 31 (0) 23 5370769 FAX: + 31 (0) 23 5393334 E-mail: [email protected]
2002 WGEXT Report 17
Mr Stig Helmig Marine and Habitat Division (by Correspondence) Danish Forest and Nature Agency Haraldsgade 53 DK-2100 Copenhagen O Denmark TEL: + 45 39472265 FAX: + 45 39279899 E-mail: [email protected]
Mr Hans Hillewaert Sea Fisheries Department, Agricultural Research Centre Ankerstraat 1 B-8400 Oostende Belgium TEL: + 32 59 342259 FAX: + 32 59 330629 E-mail: [email protected]
Jochen Christian Krause Ernst-Moritz-Arndt University Institute of Ecology Plantecology Grimmerstr. 88 D-17489 Greifswald E-mail: [email protected] [email protected] (please correspond to both addresses)
Ms. Brigitte Lauwaert Prime Minister Services Management Unit of the North Sea Mathematical Models (MUMM) Gulledelle 100 1200 Brussels Belgium TEL: + 32 2 773 21 20 FAX: + 32 2 770 69 72 E-mail: [email protected]
Michel Lemoine IFREMER Laboratoire Ressources Halieutiques Av. du Général de Gaulle 14520 Port-en-Bessin France TEL: + 33 (0) 2 3151 1300 ext 9 FAX: + 33 (0) 2 3151 1301 E-mail: [email protected]
Dr Tony Murray The Crown Estate 16 Carlton House Terrace London SW1Y 5AH TEL +44 0207 210 4322 E-mail: [email protected]
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Dr Poul Erik Nielsen Raw Material Division Danish Forest and Nature Agency Haraldsgade 53 DK-2100 Copenhagen O Denmark TEL: + 45 39 472252 FAX: + 45 39 279899 E-mail: [email protected]
Dr Dag Ottesen Geological Survey of Norway (by Correspondence) Leiv Erikssons vei 39 N-7040 Trondheim Norway TEL: + 47 73 904000 FAX: + 47 73 921620 E-mail: [email protected]
Dr Jouko Rissanen Finnish Environment Institute (by Correspondence) Impacts Research Division Kesakatu 6 00260 Helsinki Finland TEL: + 358–9-40300357 FAX: + 358–9-40300390 E-mail: [email protected]
Dr Stuart Rogers CEFAS (by Correspondence) Lowestoft Laboratory Pakefield Road Lowestoft Suffolk NR33 OHT United Kingdom TEL + 44 (0)1502 562244 FAX + 44 (0)1502 513865 E-mail: [email protected]
Mr Mark Russell BMAPA 25A Astral Gardens Hamble Southampton SO31 4RQ United Kingdom TEL: + 44 (0) 2380 458710 FAX: + 44 (0) 2380 457705 E-mail: [email protected]
Dr Ruud Schüttenhelm Netherlands Institute of Applied Geosience TNO Geo- Marine and Coast Department PO Box 80015 NL-3508 TA Utrecht The Netherlands TEL: + 31 30 2564559/4550 FAX: + 31 30 2564555 E-mail: [email protected]
2002 WGEXT Report 19
Mr Ad Stolk Ministry of Transport, Public Works and Water Management (by Correspondence) Koopmansstraat 1 P. O. Box 5807 2280 HV Rijswijk The Netherlands TEL: +31 70 3366787 FAX: +31 70 3900691 E-mail: [email protected]
Prof. Jon Side ICIT Heriot-Watt University (Chair) Old Academy Back Road Strommness, Orkney KW16 3AW United Kingdom TEL: +44 1856 850 605 FAX: + 44 1856 851 349 E-mail: [email protected]
Dr Tom Simpson Department for Transport, Local Government and the Regions Zone 4/A2 Eland House Bressenden Place London SW1E 5DU United Kingdom TEL + 44 020 7944 3868 FAX + 44 020 7944 3859 E-mail: [email protected]
Dr Chris Vivian CEFAS Burnham Laboratory Remembrance Avenue Burnham-on-Crouch Essex CMO 8HA United Kingdom TEL + 44 1621 787200/253 FAX + 44 1621 784989 E-mail: [email protected]
Ms. Henny Welleman Netherlands Institute for Fisheries Research (RIVO) P.O. Box 68 NL – 1970 AB IJmuiden The Netherlands TEL: + 31 (0) 255 564 644 FAX:+ 31 (0) 255 564 696 E-mail:[email protected]
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ANNEX 2: AGENDA ADOPTED BY WGEXT 2002
IFREMER, Boulogne-sur-mer, France, 9–13 April 2002
Host Institute for WGEXT 2002:
IFREMER Direction des Ressources Vivantes BP 32, 14520 Port en Bession Tel +33 02 31 51 13 22 Fax +33 02 31 51 13 01
Contact e-mails: Alain Grotte ([email protected]), Michel Lemoine ([email protected]) Benedict Nempont ([email protected])
THE ICES WORKING GROUP ON THE EFFECTS OF EXTRACTION OF MARINE SEDIMENTS ON THE MARINE ECOSYSTEM (WGEXT)
Tuesday 9 April 10.00–10.10 Assemble at IFREMER, Coffee 10.10–10.20 Welcome by representative of IFREMER Welcome by WGEXT Chair Appointment of Rapporteur Terms of Reference (see ICES C.Res. 2001/2E06 attached) Adoption of Agenda 10.30–12:00 Terms of reference item (a) – please supply material on disk 12.00–13.00 Lunch 13.00–14.45 Terms of reference item (a) – report on item (c) [Siân]/[Hans] 14.45–15.00 Coffee 15.00–18.30 Terms of reference (b) and finalise (c)
Aim to complete (a), (b) and (c) by day 1
Wednesday 10 April 09.00–10.30 Terms of reference item (f) and (g) 10.30–10.45 Coffee 10.45–12.00 Terms of Reference item (d) – review guidelines on the management of marine extraction operations and decide how to complete 12.00–13.00 Lunch 13.00–14.45 Terms of reference item (d) 14.45–15.00 Coffee 15.00–18.30 Parallel groups Terms of Reference items (i) and (h) – please advise if you have material to review/contribute.
Aim to know what we have to do on (f), (g) and (d)
2002 WGEXT Report 21
Thursday 11 April 09.00–10.30 Continue (and Report back) items (f), (g) and (d) and formulate report on these 10.30–10.45 Coffee (and Group photographs). 10.45–13.30 Terms of Reference item (e) 13.30–14.15 Lunch 14.30 Terms of reference (j) 15.30 Visit to the Museum of Oceanography and Dinner as guests of IFREMER
Friday 11 April 09.00–10.30 10.30–10.45 Terms of Reference item (j) 10.45–12.00 Coffee 12.00–13.00 Work on any outstanding agenda items/new agenda items/Executive Summary Any outstanding presentations 13.00–14.45 Lunch 14.45–15.00 Final agenda items and Recommendations for follow-up work 15.00–17.00 Coffee Agree text of Working Group Annual Report for 2002. Review and agree Recommendations for next Annual Meeting. Date and place of next Annual Meeting 17.00 Close of Annual Meeting Saturday 13 April 9.30–15.00 Final session for reviewing ongoing EU research projects involving WGEXT Members (SUMARE/EUMARSAND and EU SAND PIT) End User considerations. Discussion on future research projects and related initiatives.
22 2002 WGEXT Report
Scientific Justification and Supporting Information (for the Terms of Reference)
Priority: Current activities are concerned with developing the understanding necessary to ensure that marine sand and gravel extraction is managed in a sustainable manner, and that any ecosystem effects of this activity are better understood so that mitigative measures can be adopted where appropriate. These activities are considered to have a very high priority. Scientific Justification: a,b) An increasing number of ICES Member Countries undertake sand and gravel extraction activities and others (e.g., Canada) are looking at the potential for future exploitation. Each year relevant developments under these headings are reviewed and summarised. This provides a useful forum for information exchange and discussion. National reports are submitted electronically prior to the meeting and this year a new electronic reporting format has been adopted. National Reports should be submitted, using the new reporting template, no later than 16 March 2002. c) This request was made by ACME and a reporting format was adopted at WGEXT 2001. It will be tested for data returns in the coming year and reviewed at WGEXT 2002. d) The new draft guidelines (produced at WGEXT 2001) incorporate both guidance on EIA for aggregate extraction activities and guidance contained in the previous ICES Code of Practice on sand and gravel extraction. Any comments or feedback from ICES ACME and Member Countries will be reviewed and any necessary changes incorporated in the final version. e) This work is ongoing, having examined in particular studies on herring spawning grounds and on sensitivity analysis in relation to fish spawning areas generally. The means of protecting such habitats from localised effects needs further discussion, and recent work that correlates benthic data with fish occurrence will be examined as part of this. One aim is to review and develop methods for assessing the localised impact of extraction operations on fisheries. f) Risk assessment is being used in a number of ICES Member Countries for the examination of effects of, in particular, large-scale extraction projects. Its function, however, can be different in different contexts for aggregate extraction. WGEXT 2001 expressed a desire to review the uses of risk assessment methods in the management of marine sediment extraction. Those most involved in these risk assessments will meet intersessionally to prepare a summary for WGEXT 2002. It is anticipated that some members of the Working Group will meet intersessionally to initiate work to prepare a draft review for discussion at WGEXT 2002. g) Following discussions on the new draft guidelines (item c), above,) WGEXT noted that there may be agreed procedures in some ICES Member Countries for dealing with transboundary aspects of scientific research studies and EIA (under the Espoo Convention, for example). WGEXT felt it was important to establish what these arrangements were, if any, before finalising the new guidance (see item c), above). h) This information is to be provided and collated in advance of the meeting and reviewed in relation to item a). i) Following the WGEXT 2001 work on this subject, it was noted that results from a number of research studies that have employed comparative trials will be available for review. Some of these examine the applicability for geological and biological mapping. Results of this review should be exchanged with BEWG and WGMHM. j) Noting that there have been some significant developments in recent years, particularly in research on the recovery of dredged areas and in the use of a variety of acoustic techniques in monitoring studies, WGEXT felt that it was time to begin scoping the appropriate coverage and content for a follow on to the existing cooperative research report.
2002 WGEXT Report 23
Relation to Strategic Plan The principal focus of WGEXT work is in relation to Objective 2(c), but other terms of reference also relate to Objectives 1(a), 1(c), 1(e), and 4(a). Resource Requirements: Most countries collect data and information routinely on aggregate extraction activities. The additional work in presenting these data in a standardised form for the new electronic template is considered small, but will be reviewed. Reviews of research activity are of programmes that are already under way and have resources committed. Participants: WGEXT is normally attended by 20–25 members and guests.
Secretariat Facilities: WGEXT 2002 will be hosted by IFREMER in France.
Financial: No additional financial implications.
Linkages to Advisory Committees: ACME
Linkages to other Committees or BEWG, WGMHM Groups:
Linkages to other Organisations: Work is of direct interest to OSPAR and HELCOM.
Cost share ICES 100 %
24 2002 WGEXT Report
ANNEX 3: REVIEW OF NATIONAL MARINE AGGREGATE EXTRACTION ACTIVITIES
A detailed breakdown of each country’s sediment extraction dredging activities is provided below:
1 Belgium
Figure A3.1 Extraction areas on the Belgian shelf.
During 2001, a quantity of 1,911,057 m³ sand has been extracted on the Belgian continental shelf, in the same areas (Zone 1 and Zone 2, see Figure A3.1) as in previous years. Today, sixteen licences have been granted, three new applications are under consideration, and also one application for exploration is under study. An historical overview of all extractions since 1988 is given in Figure A3.2.
Total extraction of marine aggregate
4,500,000
4,000,000
3,500,000
3,000,000 ) ³ m
( 2,500,000 n o i t c
a 2,000,000 r ext 1,500,000
1,000,000
500,000
0 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year Figure4: Historical pattern of extraction
Figure A3.2 Historical pattern of extraction in Belgium.
2002 WGEXT Report 25
2 Canada
Under the leadership of Natural Resources Canada, the federal Canadian government is about to (April 2002) make a decision on the continuance of developing a framework to permit and control marine mining through a project termed OMMI (Offshore Minerals Management Initiative) which began in 1998. The Provinces of British Columbia, Nova Scotia and Newfoundland were the prime provinces in requesting the initiative. Over the past four years, documents have been prepared on the resource potential, socio-economic implications, technological assessment, environmental assessment and risks and opportunities associated with a marine mining regime for Canada.
Consultations that were planned with focus groups for 2001 and 2002 have been cancelled. Web-based ocean mining information documents and a questionnaire designed to receive feedback on risks and opportunities associated with marine mining have not been released. Present plans are to make factual background information on environment, socio-economic and technical resource aspects available over a longer term to the public.
The marine mineral extraction industry continues to express interest in mining for offshore placers and aggregates, but the absence of a government legislative framework remains as a deterrent to further investment and investigation. Two industrial companies have expressed a strong interest in mining titanium from river and nearshore sands and large coarse, sand wave aggregate deposits in the Bay of Fundy. These waters are considered under provincial control and may not involve the federal government on resource management issues.
3 Denmark
The extraction of marine sand and gravel represent 10–20 % of the total production of materials for construction and reclamation.
Figure A3.3 Production of sand and gravel in Denmark 1978–2001 (the figures for 2001 are preliminary).
14000000
12000000
10000000
8000000 m³
6000000
4000000
2000000
0
8 7 4 6 81 90 93 99 980 986 989 998 197 1979 1 19 1982 1983 1984 1985 1 198 1988 1 19 1991 1992 19 199 1995 199 1997 1 19 2000 2001
Sand Fine gravel Coarse gravel Sand fill Total
The production of construction aggregates has remained stable over the past five years. However, the production of coarse aggregates has been slightly decreasing.
The dredging of sand fill for land reclamation has increased markedly over the past ten years caused by several large construction works in coastal areas (Figure A3.3).
26 2002 WGEXT Report
From 1989 to 1993 more than 9 million m3 of sand fill and till were dredged for the construction of the Great Belt Bridge and tunnel project.
During the construction of the fixed link between Denmark and Sweden 1.3 million m³ of sand was dredged with a spill rate of only 2.8 %. In the same period 7 million m³ of dredged materials, glacial till and limestone was reused for reclamation and as hydraulic fill in ramps for the bridge and tunnel.
A major enlargement of the harbour of Århus has required more than 8 million m³ of sand fill. The construction works started in the autumn of 1998 and were completed in 2000. A total of 8 million m³ was dredged from two areas in Århus Bight. The spill from the dredging operations was 3.7 %. Only a few reclamation projects have been carried out in 2001. Approximately 200,000 m³ of sand fill was exported to Germany in 2001.
The consumption of sand for beach nourishment at the West Coast of Jutland has shown a pronounced increase from 40,000 m³ in 1980 to more than 3.5 million m³ in 1998 (Figure A3.4) The consumption has now stabilised around 2.5 million m³/year.
8000000
7000000
6000000
5000000
4000000 m³
3000000
2000000
1000000
0
5 5 86 87 96 97 978 979 988 989 998 999 1 1 1980 1981 1982 1983 1984 198 19 19 1 1 1990 1991 1992 1993 1994 199 19 19 1 1 2000 2001
Beach Nourishment Reclamation
Figure A3.4 Production of sand for beach nourishment and reclamation in Denmark. (The figures for 2001 are preliminary).
No detailed forecast for the future extraction has been prepared. In general, the extraction varies in line with the development of the national economy.
Several major construction works considerably increased the demand for sand fill between 1995 and 2000. These projects finished during 2000 and the demand has decreased considerably since.
However, a further enlargement of the Århus Harbour is expected to take place from 2002–2003 and will require up to 7 million m³ of sand fill.
A project for the construction of a major container terminal near Stigsnæs, southern Sjælland, is being planned. The project will require 1–3 million m³ of sand fill from resource areas within the vicinity of the construction area. The construction is expected to start in 2003.
2002 WGEXT Report 27
It is expected that the total marine extraction of construction aggregates will remain at the current level over the next five years.
4 Finland
Sand and gravel extraction from Finnish coastal areas has been negligible in recent years. Since 1996 no major marine sand or gravel extractions have been reported. The Harbour of Helsinki has permission to extract 8 million m3, but the extraction has not started. The Forest and Park Service has applied for permission to extract 12 million m3 of sand off Helsinki between 2002 and 2011. The Environmental Impact Assessment of this application was completed in 2001.
5 France
Table A3.1 Marine aggregate (sand and gravel) extraction figures for France for 2000/2001.
DREDGING AREA AMOUNT * Normandy 444 000 m3 Brittany 38 000 m3 Atlantic coast 1 945 000 m3 TOTAL 2 427 000 m3 Siliceous aggregate 1.6 t/ m3
The amount of aggregate extraction has remained stable in France for many years.
Table A3.2. Historic patterns of marine aggregate extraction in France.
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Total 1990–2000 2 1.9 1.9 2.5 2.5 2.3 2.6 2.6 2.6 2.6 23.5
Table A3.3. Non-aggregate (e.g., shell, maerl, boulders etc) extraction figures for France for 2000/2001.
DREDGING AREA MATERIAL AMOUNT * North Brittany Maerl 215 000 m3 North Brittany Shelly sands 143 000 m3 West Brittany Maerl 2 700 m3 West Brittany Shelly sands 26 700 m3 South Brittany Maerl 82 000 m3 Total 469 400 m3 Note that for calcareous aggregate a conversion rate of 1.3 t m–3 has been used.
Current licence position and forecasts for future exploitation of marine aggregates
• 12 sites are being exploited; • 2 licences for exploitation are under consideration; • 2 licences for research purposes are under consideration.
28 2002 WGEXT Report
6 Ireland
No permits for commercial marine aggregate extraction were issued in 2001. There were no data available on other extraction activities.
7 The Netherlands
Table A3.4. Marine aggregate (sand and gravel) extraction figures for the Netherlands for 2001/2002.
DREDGING AREA AMOUNT Euro-/Maas access-channel to Rotterdam 10.3 Mm3 IJ-access-channel to Amsterdam 2.3 Mm3 Dutch Continental Shelf 23.8 Mm3 Total 36.4 Mm3
Of the total, 13.14 Mm3 has been used for beach replenishment projects.
Table A3.5. Non-aggregate (e.g., shell, maerl, boulders etc) extraction figures for the Netherlands for 2001/2002.
DREDGING AREA MATERIAL AMOUNT Wadden Sea Shells 90,474 m3 Wadden Sea inlets Shells 105,997 m3 Western Scheldt Shells 5,360 m3 North Sea Shells 59,685 m3 Voordelta of the North Sea Shells 20,865 m3
Description of non-aggregate extraction activities in 2001/2002
As a result of the National Policy Note and EIA for shell extraction (15 December 1998), there are maximum permissible amounts defined from 1999 onwards.
The permissible amounts (in m³) of shell to be extracted from: the Wadden Sea is 120,000; the sea inlets between the isles 90,000; the Voordelta of the North Sea 40,000; the Western Scheldt 40,000; the rest of the North Sea up to a distance of 50 km offshore (there is no fixed amount).
Table A3.6 Exports of marine aggregate from the Netherlands in 2001/2002.
PORT (landing) AMOUNT Belgium Approx. 1.5 Mm3 (exact figures are not known)
2002 WGEXT Report 29
Marine aggregate exports in 2001/2002
There is a continuous flow of sand extracted from the extraction areas in the southern part of the Dutch sector of the North Sea, which is used for landfill and for concrete and building industries.
Table A3.7 Amount of material extracted in the Netherlands for beach replenishment projects in 2001/2002.
DREDGING AREA MATERIAL AMOUNT * L 12D (coast of Vlieland) Sand 1.52 Mm3 Q10F (coast of Noord-Holland) Sand 0.93 Mm3 Q2A (coast of Noord-Holland) Sand 1.51 Mm3 Q5C (coast of Noord-Holland) Sand 1.98 Mm3 Q16C-5 (coast of Zuid-Holland) Sand 0.11 Mm3 Q16D (coast of Zuid-Holland) Sand 0.19 Mm3 Q16E (coast of Zuid-Holland) Sand 4.18 Mm3 S3B (coast of Zuid-Holland) Sand 0.65 Mm3 S8B (coast of Zeeland) Sand 2.08 Mm3 Total Sand 13.14 Mm3
Table A3.8 Historic patterns of marine aggregate extraction in the Netherlands in Mm3.
Extraction Area 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Total 1990– 2001 Euro-/Maas channel 2.31 2.56 6.76 0.35 4.80 7.51 9.97 8.31 5.71 1.36 6.83 10.32 66.79 IJ-channel 4.98 3.61 2.67 2.84 4.15 3.30 4.78 4.18 6.33 5.06 4.78 2.31 48.99 Dutch Continental 6.07 6.60 5.36 9.83 4.61 6.02 8.39 10.26 10.46 15.99 13.82 23.81 121.22 Shelf Total extracted 13.36 12.77 14.80 13.02 13.55 16.83 23.15 22.75 22.51 22.40 25.42 36.45 237.00
Historic patterns of marine aggregate extraction from 1974 out of the Dutch part of the North Sea 40,000,000 35,000,000 IJ-Channel + Maas-/Euro-Channel Dutch Continental Shelf. 30,000,000 Total 25,000,000 20,000,000 m³ 15,000,000 10,000,000 5,000,000 - 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 year
Figure A3.5 Historic patterns of marine aggregate extraction from 1974 out of the Dutch part of the North Sea.
30 2002 WGEXT Report
Description of historic extraction activities for 1990–2001
The higher financial contribution from the Ministry of Transport, Public Works and Water Management and the choice for beach replenishments by means of sand re-nourishment on the foreshore instead or on the beach is the cause for the increase in sand-demand shown above.
Summary of current licence position and forecasts for future exploitation of marine aggregates
Table A3.9 Licences considered and issued by Rijkswaterstaat North Sea Directorate over the past three years.
In the year: Number 1998 35 1999 30 2000 25 2001 27 2002 April 17
In April 2002, 56 licences were in preparation.
8 Sweden
Marine aggregate extraction of sand for construction and industrial purposes ended in Sweden in 1992. This change was due partly to environmental concerns and partly to the use of land resources (mainly in the form of crushed bedrock). In 1998, new stretches of the Flint shipping channel between the Saltholm Island and the coast of Scania were dredged in connection with the construction of the new Øresund Link between Sweden and Denmark. All the materials dredged were used for the construction of two islands south of the Saltholm Island on the Danish side of the Sound.
Table A3.10 Historic patterns of marine aggregate extraction in Sweden during 1989 to 2001.
Extraction Area 1989 1990 1991 1992 1993–97 1998 1999–2001 Total in m3 m3 m3 m3 m3 m3 m3 m3 1989–2001 Sandflyttan 1, 692 1, 692 423 3, 807 Vastra Haken 35, 509 31, 302 33, 840 52, 739 152, 390 St. Middelgrund 30, 768 138, 776 82, 534 252, 078 Faro 2, 400 2, 400 Øresund Link* 2, 500, 000 2, 500, 000 Yearly total 70, 369 171, 770 116, 797 52, 739 0 2, 500, 000 0 911, 675 * Used for landfill.
Current licence position
The municipality of Ystad, southern Scania is applying for permission to extract 500,000 m3 for ten years on the bank of Sandhammaren for beach nourishment. The application is being processed by SGU.
2002 WGEXT Report 31
9 United Kingdom
Table A3.11 Marine aggregate (sand and gravel) extraction figures for 2001 for the UK. (Includes aggregate and material for beach replenishment and fill contract)
DREDGING AREA AMOUNT (tonnes) Humber 3,168,218 East Coast 9,636,697 Thames 1,121,084 South Coast 5,638,694 South West Coast 1,549,431 North West Coast 421,068 Rivers and Miscellaneous 1,227,135 TOTAL 22,762,327
Licences especially for fill contracts and beach replenishment were as follows:
• Contract Fill 1,366,031 tonnes; • Beach Replenishment 245,281 tonnes.
Non-aggregate (e.g., shell, maerl, boulders, etc.) extraction figures for 2001.
There was no calcareous seaweed extracted from Crown Estate licences during 2001.
Table A3.12 Exports of marine aggregate from the UK in 2001.
PORT (landing) AMOUNT (tonnes) Amsterdam 2,208,989 Antwerp 715,552 Brugge 447,458 Calais 135,916 Dunkirk 623,128 Fecamp 98,016 Flushing 972,176 Harlingen 341,632 Honfleur 60,646 Nieupoort 137,763 Ostend 482,907 Roscoff 47,234 Rotterdam 338,740 Vatteville 13,809 Zeebrugge 368,765 TOTAL 6,992,731
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Table A3.13 Amount of material extracted for beach replenishment projects in 2001.
DREDGING AREA MATERIAL AMOUNT (tonnes) Mapplethorpe/Skegness Sand 234,595 Pevensey Bay Shingle 10,686 TOTAL 245,281
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2002 WGEXT Re Table A3.14. Historic patterns of marine aggregate extraction in the UK (tonnes). (Figures exclude beach replenishment and fill contracts)
Extraction Area 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Total p ort Humber 0 0 0 1,910,064 1,788,452 1,903,678 2,351,233 2,694,977 2,840,261 3,122,080 2,933,623 19,544,368 East Coast 9,220,517 10,255,813 9,812,236 9,384,860 10,497,352 9,306,920 9,397,705 8,923,562 9,131,512 9,129,635 9,636,697 104,696,809 Thames 1,505,111 1,504,471 1,223,190 2,001,208 1,661,324 1,115,597 1,125,921 862,834 971,960 854,483 909,141 13,735,240 South Coast 5,280,685 4,794,290 4,361,796 4,932,372 4,428,357 4,738,402 4,733,825 5,821,701 5,885,332 5,613,538 5,628,008 56,218,306 South West Coast 2,065,841 2,388,148 2,172,576 2,259,046 2,285,899 2,019,305 2,048,014 1,886,289 1,719,803 1,602,394 1,549,431 21,996,746 North West Coast 305,654 310,782 380,336 290,846 278,126 287,251 284,497 275,590 355,044 316,090 421,068 3,505,284 Rivers and Misc. 40,236 17,998 12,651 14,491 14,114 21,784 18,587 6,238 6,273 46,120 73,047 271,539 Yearly Total 18,418,044 19,271,502 17,962,785 20,792,887 20,953,624 19,392,937 19,959,782 20,471,191 20,910,185 20,684,340 21,151,015 219,968,292
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34 2002 WGEXT Report
Summary of the current licence position and forecasts for the future exploitation of marine aggregates (01/03/2002):
• 72 Extraction licences containing approximately 263 million tonnes of marine sand and gravel; • 20 Applications in the Government View Procedure containing approximately 553 million tonnes of marine sand and gravel; • 25 Pre-Government View Procedure licences; • 4 Current prospecting licences.
10 United States of America
Little has changed in the United States. There is only one commercial sand and gravel company using offshore sand sources. They mine sand from the main shipping channel into NY Harbour (Ambrose Channel). This material is often mixed with crushed rock to provide the grade required by users in the NY metropolitan region. They extract about 1.3 million cubic metres per year.
Larger but similar volumes are extracted annually for beach renourishment, often from sand deposits that have accumulated in navigable inlets or waterways but in some instances, from designated borrow areas. The total volume of sand used for beach nourishment in the NE Atlantic coast was about 2,129,000 cubic metres in 2001.
Table A3.15 Marine aggregate (sand and gravel) extraction figures for 2001/2002 for the U.S.
DREDGING AREA AMOUNT New York Harbor 1,300,000 m3
Table A3.16 Amount of material extracted for beach replenishment projects 2001/2002 for the U.S.
DREDGING AREA MATERIAL AMOUNT New York Intercoastal Waterway Sand 479,000m3 New York Bight Sand 1,650,000m3 New York Harbor Sand 80,000m3
Description of beach replenishment schemes on 2001/2002
A total of 2,129,000 m3 of sand was placed on the Atlantic beaches of Long Island, New York. Within New York Harbor, sand was backpassed to maintain the renourishment project at Coney Island in New York City. There were no renourishment projects in New Jersey, or other areas in the NE Atlantic Coast.
Table A3.17 Historic patterns of marine aggregate extraction in the U.S.
Extraction 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Total Area 1990– 2001 NE Atl. 0.2 0.8 0.8 1.5 1.7 1.4 c1.4 c1.4 c1.3 1.3 1.1 1.3 14.2
2002 WGEXT Report 35
ANNEX 4: REVIEW OF NATIONAL SEABED RESOURCE MAPPING PROGRAMMES
1 Belgium
Resource mapping is within the responsibility of the Belgian geological survey. No seabed mapping was undertaken in 2001.
2 Canada
Marine geoscience mapping is the responsibility of the Geological Survey of Canada (GSC), with projects on the Atlantic, Pacific and Arctic coasts. Surveys are conducted in the nearshore, on the continental shelf, and slope. A second round (Spring 2002) of changes to the scientific project definition and selection process by the Geological Survey of Canada has resulted in further curtailment to projects of seabed resource assessment and regional mapping. Existing mapping programs are presently focusing on the southern areas of Canada where societal pressures are the greatest and partners exist. These include programs for habitat mapping; in deep water slope areas where potential exists for hydrocarbon development; studies associated with seabed engineering hazard characterisation; and in newly declared marine protected areas for habitat and terrain characterisation.
A renewed interest in the Beaufort Sea over the past year, after a 10-year hiatus, resulted in the application of multibeam bathymetry to an assessment of sea ice pressure ridge keels on the seabed and the long-term fate of artificial islands constructed for hydrocarbon drilling platforms. The islands were made from seabed and subsurface granular materials and at the time these projects represented some of the world’s largest offshore mining operations. The results of the surveys showed spectacular images as some of the islands have migrated shoreward and have been eroded on their upper surfaces. New pressure ridge ice scouring has in some areas completely rearranged seabed sediments and the previous pattern of scour marks. Gas-escape pockmarks are present in some areas.
The collection of multibeam bathymetric data is considered the most important first step in seabed resource mapping. Cooperative survey efforts are in place with the Canadian Hydrographic Service to collect this information.
Other projects regarding seabed habitat characterisation will continue in the Gulf of Maine. Many in the fishing community have embraced the new seafloor mapping technologies as essential tools for a sustainable fishery and to maximise their operations for efficient and safe fishing practices.
A proposal for a Canadian regional systematic multibeam mapping project called “SeaMap” has not yet been approved. The proposal document was intended to be presented to government for approval in 2001 but was not initially funded and remains on the list of projects for future consideration. If implemented, Canada would establish a new long-term high-resolution seabed-mapping program to serve a multitude of users. It would include the production of multibeam bathymetric, backscatter and slope assessments as well as geological interpretative products of sediment distribution, habitat, seabed dynamics and hazards. To prepare for the SeaMap project, a new study was undertaken during the past year to develop Canadian standards and a template for map production including scales, projections, legends, formats and a release and storage protocol for digital maps.
3 Denmark
Mapping of the seabed is an integrated part of the systematic reconnaissance resource mapping programme in Danish Waters.
The mapping programme continues and is concentrated in The North Sea, Kattegat and The Baltic. Since 1991, mapping programs have been carried out on Jutland Bank and Horns Reef in The North Sea and in Femer Belt, Adler Ground, Rønne Banke and Kriegers Flak in The Baltic. Maps of surface sediments, Quaternary geology and sand and gravel resources have been prepared at 1: 100,000. At present, between 80 % and 90 % of potential resource areas in the Inner Danish Waters have been mapped (Figures A4.1 and A4.2).
In 1999 and 2000 reconnaissance mapping was carried out in deeper water in the central part of Kattegat and in the North Sea. The preliminary results indicate the presence of potential resources in the deeper parts of the Kattegat area.
36 2002 WGEXT Report
Figure A4.1 Mapping programme in Danish Waters. Dark shaded areas indicate where surface sediment maps have been prepared during the reconnaissance mapping program (unpublished and published data).
Detailed resource mapping programmes have been carried out in some of the regional extraction areas with materials of high quality and in areas licensed for bridge and tunnel projects.
In 1999, detailed seabed mapping was carried out for a possible fixed link between Germany and Denmark in the Femer Belt between Putgarten and Rødby.
2002 WGEXT Report 37
Figure A4.2. Seismic surveys in the North Sea and the Baltic, January 2001. The figure shows the coverage of seismic data collected during resource mapping and scientific projects. (Recent data from the Skagerrak have not been processed.)
A surface sediment map of the Jutland Bank, North Sea will be published in 2002.
In 2000, detailed seabed mapping programs were carried out in relation to applications for dredging permits, e.g., in the Bay of Århus, Kattegat, Great Belt and North Sea.
Along the Jutland west coast GEUS has completed a major mapping project commissioned by the Danish Coastal Authority (DCA). The study is using seismic surveys, samplings and corings (Leth et al., 2001).
Results from the projects will be published in the near future, e.g., Anthony and Leth, 2002.
On Horns Rev west of Jutland, GEUS has completed a major sediment transport study also commissioned by the Danish Coastal Authority (DCA).
The existing map “Bottom Sediments around Denmark and the Western Sweden” has been updated with results from the recent mapping projects and has been published on a CD-ROM. The CD-ROM is available from GEUS.
4 Finland
A study of marine geology by the Geological Survey of Finland (GTK) concerning late-Quaternary deposits on the seabed is being conducted using acoustic and seismic methods: echo sounders, single-channel seismics and side-scan sonar. Investigations are supplemented with seabed sampling and visual observations. The basic scope of the study is to acquire data on the distribution and thickness of various types of sediments and information on stratigraphy, mineralogy and geochemistry of the deposits. New methods of sounding and sampling as well as data processing and analysis of samples are also being developed and tested. The aim of the study is also to increase knowledge of the physical properties and the geochemical variations in seabed sediments induced both naturally and by the human activity. Also the demand of various practical and scientific needs arising in the surrounding community should be met. The annual goal of the seabed survey is 700 km². Some information on survey methods and data processing can be found at http://www.gtk.fi/marine.html. Meta-data of samples carried out by GTK are available from the EU- SEASED meta-database (http://www.eu-seased.net).
38 2002 WGEXT Report
5 France
IFREMER (Marine Geosciences Department) has undertaken seabed mapping programmes since 2000. The general survey methods employed include side-scan sonar, multibeam bathymetry, echosounder, high resolution seismics, grabs, corers and video techniques.
Published seabed resource maps in 2001/2002:
Morphological map of The Gulf of Lion (Mediterranean).
More information on seabed mapping programmes can be obtained from the following web address: http://www.ifremer.fr/drogm/Realisation/Bathy_Carto/Plateau/index.html
Biosedimentary Mapping
In 1976, Chassé and Glemarec proposed maps of sedimentary ecology (biosedimentary maps) for marine soft substrates should be completed.
These should be based on:
• distribution of macrobenthic species, their affinities between them and with sediment. Epifauna, macrofauna and fish are not considered; • efficient ecological characteristics of sediment (stability, trophic value) rather than on a single granulometric parameter. This characterisation takes in account: - sediment dynamics linked to hydrodynamism (currents, shoal); - granulometric characteristics; - the qualitative and quantitative determination of the different communities.
In the Gulf of Biscay, Chassé and Glemarec identified 10 biosedimentary facies according to the nature and granulometry of bottom sediments, from clean gravels with bivalves to muds with annelids and sea-urchins.
Note: Substrate characteristics are less selective with depth; for each kind of substrate, three zones are considered (infralittoral, coastal and offshore). Only a few species differ between infralittoral and coastal communities, but the former are more densely populated (numerously more abundant); on the other side, offshore communities are qualitatively very different and less abundant. The most diversified communities are found in each zone in muddy fine sands; diversity is increasing for each sedimentary type from the coast to offshore.
Mapping at 1:100,000 is an appropriate scale for detailed studies such as on environmental impact prior to extraction operations.
Production of such maps needs a standardisation of existing data to get a framework in which all benthic studies can become integrated.
This biosedimentary mapping can be used to assess the biological richness of the different marine bottoms and their quantitative relationships with fishing activity.
Most of aggregate extraction areas are located in the infralittoral zone (15 m to 30 m depth) where temperature variations are maximal.
Edaphic conditions are the most selective in this zone, communities the most abundant but less diversified than offshore; thus, the muddy fine sand facies is the richest in species, densities and biomass (up to more than 30 g/m2): it is the coastal nurseries; at the opposite, this zone includes the poorest facies for biomass (lower than 5 g/m2) corresponding to coarse sands and gravels and mainly mobile sand-dunes.
2002 WGEXT Report 39
2002 WGEXT Report Table A4.1 Classification of seabed sediments according to a Biological Sensitivity Index based on the trophic value (biomass in g. m−2) and the habitat importance (rarity, functionality, biodiversity).
Biological Facies 1969–1977 1976 1975–1977 1980–1999 1980 1995–1999 1994–1999 Sensitivity Bay of Pertuis Bay of Seine Dieppe North Sea Terschell (NL) Norfolk(GB) Index Biscay Atlantic Coast
1 Mobile medium sands Biomass ~0 0.4 1–3 Abundance 100–500 2 Clean gravels Biomass 1–2 Abundance 3 Coarse sands with Biomass 2–4 2–6 8–12 7–12 Amphioxus Abundance 1000–2500 1000–3000 1000–2000 4 Clean fine sands Biomass 4–10 1 4 5– 25 Abundance 700 4000–10000 5 Heterogeneous muddy Biomass 5– 30 1–55 30 sands Abundance 210 6 Muddy fine sands Biomass 10–30 11 7–125 40 20–400 Abundance 1400–6000 up to 5000 2000 7 Sandy muds Biomass 15–30 27 Abundance 8 Maerl Biomass 20–30 Abundance 9 Shingle Biomass 1000–2000 250 Abundance 2000–3000
39
40 2002 WGEXT Report
Table A4.1 summarises quantitative data available on the different biosedimentary facies along the French coast where aggregate resources have been located.
These facies are classified along a growing Biological Sensitiveness Index based on their biomass (trophic value); supplementary data from two European extraction sites are given for comparison.
This classification shows that clean coarse bottoms, generally located in high energy areas, are less sensitive to extractions in terms of benthic richness and thus of trophic interest for demersal fish.
Note: coarse sand and gravel bottoms can be of high sensitiveness when they are spawning grounds for fish and shellfish resources.
Chassé and Glemarec “translate” biomass values in richness index:
• the biological richness of a facies is expressed in organic matter production per time and surface area; it is the benthic food available for consumers; • the economic richness of a facies is its ability to sustain commercial fishing of molluscs, crustaceans and fish.
This index is expressed in kg of commercial fish per ha for every area of equivalent biomass:
Benthic biomass Richness Index (g m–2) (Kg ha –1) 40 20 20 10 10 5 5 2,5 1 0,5
Reference
Chassé C., and Glemarec M. 1976 Principes généraux de la classification des fonds pour la cartographie biosédimentaire. J. Rech. Océanogr, I (3): 1–18.
6 Ireland
Developments in Marine Resource Mapping are ongoing and as reported last year.
7 The Netherlands
Resource mapping is the responsibility of the national geological survey. The survey is a component body of the national applied science and technology conglomerate TNO named “Netherlands Institute of Applied Geoscience TNO, - national geological survey”.
A review of the progress in the field of seabed resource mapping in 2001/2002 is presented below, including corresponding maps that show the advancement of the mapping programmes.
1:250,000 geological reconnaissance map series
This map series consists amongst others of a surface geology (seabed sediments) sheet, which includes a main map in UTM (ED 50) at 1:250,000 showing the uppermost 10 cm of the seabed following the Folk classification system and various subsidiary maps. These maps at 1:1,000,000 include the seismic line grid, thickness of Holocene sediments, depth to the base of the Holocene sediments, distribution of (older) Holocene formations, mean grain size, biogenic and lithic gravel content and/or carbonate content of sand fraction, geochemistry of surface sediments (Oyster Grounds map), a key to colours and symbols and a short description. Each mapped area covers 1° latitude and 2° longitude.
All the sheets of the 6 mapped areas are now available in digital format. A seabed sediment map of Terschelling Bank (53°–54ºN, 4°–6ºE) is in preparation.
2002 WGEXT Report 41
Figure A4.3 Map of the Dutch sector of the North Sea with the 1:250,000 map sheet subdivision and the progress of this mapping programme.
1:100,000 geology and resource map series
This map series consists of digital map sheets with both geological and resource information.
The geological component includes a fence diagram with the geological structure of the younger layers (1:100,000), a bathymetric map at 1:150,000, 1:250,000 maps on geomorphology, on the occurrence of Holocene formations, on thickness of Holocene and of Pleistocene deposits, a fence diagram of older sediments, nature and depth of the top Pleistocene and of the top Tertiary and a short description of, amongst others, the stratigraphic units.
The resource component includes a map of the mean grain size and mud content of the uppermost metre on 1:100,000, a similar map of the metre below at 1:150,000 and 1:250,000 maps of the carbonate content in the first and the second metre, on lithic and biogenic gravel contents in the first and second metre, on interfering (clayey) layers in the first and
42 2002 WGEXT Report
in the second metre and a short note on methodology, sediment classification and on the availability of further information. Digital grain-size information is also available for the 2–3 m and 3–4 m below seabed intervals.
The map sheet for Rabsbank (51°20’–51°40’N, 3°–3°40’E) and Buitenbanken (51º 40’–52ºN, 3°–3º 40’E) have been published as well (in 1992 and 1996 respectively). Schouwenbank (51º 40’–52ºN, 3º 40’–4º 30’E) was the first sheet to become available in digital form only. The Indusbank (52°–52º 20’N, 3º 50’–4º 30’E) and IJmuiden Ground (52º 20’– 52º 40’N, 4°–4º 40’E) sheets are in various states of progress. Work on the Indus Bank sheet has almost been completed, the digital resource maps have been finalised. Data acquisition on the next sheets to the north i.e., Egmond Gronden (52˚ 40’–53˚ 00’N, 3˚ 50’–4˚ 30’E) as well as the offshore part of the adjoining Fransche Bank sheet (52˚ 40’–53˚ 00’N, 4˚ 30’–5˚ 10’E) is completed, the inshore part of the latter sheet remains to be done. The Keysersplaat sheet (53˚ 00–53˚ 20’N, 4˚ 20’–5˚ 00’E) survey programme is currently under way. This sheet covers the marine areas around Texel island. A geophysical survey programme has started on all map sheets immediately north of the Frisian Islands.
The survey methods employed in the data acquisition phase of the mapping programmes include sampling and coring devices such as the Hamon grab (for sand and gravel down to 0.2 m), electric and hydraulic vibrocorers (for short cores 1 m and 4–5 m in length, respectively), and Geodoff and Roflush counterflush sampling systems (for disturbed sub- seabed samples down to 12 m and 25 m respectively). Seabed and sub-seabed information is obtained by conventional echo-sounders and multibeam (bathymetry), side-scan sonar and multibeam (morphology), various subbottom profilers (the uppermost few tens of metres max.) and sleeve guns (the Quaternary succession reaching thicknesses of many hundreds of metres).
Figure A4.4 Map of the Dutch sector of the North Sea with the 1:100,000 map sheet subdivision.
2002 WGEXT Report 43
Published seabed resource maps in 2001/2002
As stated above, six sheets of the 1:250,000 series have been published from 1984 onwards, a seventh sheet is currently in preparation. Only the first two sheets of the 1:100,000 series have been printed in 1992 and 1996, respectively. These and all further sheets are available in digital format. Based on the institute’s digital database a specific map of any part of the (sub)seabed of the Dutch sector can be produced.
Future marine resource mapping programmes
Currently a few research initiatives are being carried out that focus on seabed dynamics and so, have a direct relation with survey techniques, resource mapping, extraction policies and environmental monitoring.
In 1999 a 3-year research project was started to investigate the grain size variability in relation to crest stability in space and time of a North Sea sandwave in block S2. TNO-NITG and Rijkswaterstaat North Sea Directorate are surveying twice a year to establish the grain size at and near the surface and the nature and evolution of the bedforms present. The outcome of this study scheduled for 2002 will be useful not only for detailed extraction policies in areas with sandwaves and/or other bedforms but also for (natural) variability of grain size data and reliability of archive data.
A research project, begun in 2000, is running on the relation between seabed morphodynamics, sediment transport and ecology. Study areas include a small area on the toe of the shoreface, a small part of a shoreface-connected ridge and a short transect in a sandwave field. Results are expected by 2002. A related project is aiming to classify seabed sediment using sonar.
Applied and other geological investigations in 2001
A number of studies have been carried out in the past year to evaluate potential deep and seabed extraction sites for raw materials especially industrial sand (concrete and mortar sand) and gravel. Infill sand is a by-product.
Several were related to the evaluation of industrial sand resources present in fluvial deposits dating from the last sea- level low-stand. The target last year was the course of the River Rhine when the North Sea was dry land. Any finer- grained (d50 < 500 mµ) seabed sands covering the industrial sand resources could be used as either infill sand or beach recharge material.
Of interest was the performance of NITGs’ Roflush counterflush drilling equipment which successfully completed a few hundred borings down to 25 metres below seabed.
Reports include:
Kok, P.T.J. et al. 2001. Onderzoek voorkomen beton- en metselzand Noordzee, Interimrapportage tweede tranche. (Study of Concrete and Mortar sand occurrences in the North Sea, Interim Report, 2d part), Rept. NITG 01–088- C (in Dutch), 18 p. + appendices.
Kok, P.T.J. et al. 2001. Onderzoek voorkomen beton- en metselzand Noordzee, Interimrapportage derde tranche. (Study of Concrete and Mortar sand occurrences in the North Sea, Interim Report, 3d part), Rept. NITG 01–172- C (in Dutch), 20 p. + appendices.
Kok, P.T.J. et al. 2002. Onderzoek voorkomen beton- en metselzand Noordzee, Interimrapportage zuidwestelijk deel gebied van onderzoek, vierde tranche (zandwingebied WCT). (Study of Concrete and Mortar sand occurrences in the North Sea, Interim Report, SW part of the study area, 4th part (WCT sand extraction area)), Rept. NITG 02– 002-C (in Dutch), 15 p. + appendices.
Another group of studies related to the evaluation of gravel and associated concrete and mortar sand deposits on Cleaver Bank. Both quantity and quality were studied. These deposits are of glacial origin and date from the Late Weichselian (Devensian) ice advance c. 20,000 years ago).
44 2002 WGEXT Report
Reports include:
Laban, C. 2002. Geologisch Onderzoek grindgebied Klaverbank – Samenvattend rapport onderzoek uitgevoerd van 1979 tot en met 2001. (Geological investigations Cleaverbank gravel area – Report summarising the 1979–2001 investigations), Rept. NITG 01–003-A (in Dutch), 27 p. + appendices.
Geochemical distribution graphs of surface sediments, as outlined in an earlier ICES progress report, are now being prepared for the entire Dutch sector. The aim is to have reliable information on natural background values and their variation and therefore to be able to distinguish human-induced changes. Occasionally longer cores are investigated as well. In doing so, the thickness of the youngest layer (mobile since the start of the industrial revolution) may be estimated.
8 Sweden
The distribution of seabed sediments within the Swedish EEZ is well known on a mere 17 % of the area, i.e., about 25,000 km2 out of a total zone of 160,000 km2. The knowledge of this area is due to the marine geological mapping programme carried out by the Geological Survey of Sweden (SGU), and the subsequent production by SGU of a marine geological database and a series of maps at scales of either 1:50,000 or 1:100,000. The areas mapped at these scales are (within brackets the years of fieldwork):
• the Sound (1973–1977); • the area north of Gotland (1978–1983); • the Swedish EEZ of Kattegat (1985–1992, 1999–2000); • the Swedish EEZ south of Scania (1993–1994); • the Stockholm archipelago (1995–1999); • the southern part of the Swedish Skagerrak coast (2000); • the Norrköping area (2001); • the Lake Malaren (2001).
In order to get a relatively fast overview of the Swedish seabed, SGU started a reconnaissance survey in 2000, on behalf of the government, aimed to cover the total EEZ with a sparse grid of survey lines within eight years. These data will be saved in databases and finally compiled in maps at a scale of 1:500,000. The following area has been mapped:
• the Swedish EEZ of Skagerrak (2000).
The present knowledge of the Swedish seabed outside mapped areas is limited to sparse information in old bathymetric surveys carried out by the Maritime Board (Navigational Charts) and patchy information given by fishermen and from scientific and applied research carried out by universities and companies. The latter type of information together with surveys carried out by Geological Surveys in Sweden and other countries around the Baltic Sea have been compiled to outlined bottom sediment maps of the Central Baltic (Rupecka and Cato 1998) and the southwestern Baltic, Kattegatt and Skagerrak (Kuijpers et al., 1994) at the scale of 1:500,000.
In 2002, the mapping programme will continue with the area off Gavle (in the scale 1:100,000) and the Swedish EEZ of the southern Bothnian Sea (in the scale 1:500,000).
2002 WGEXT Report 45
Figure12: The plan of marine geological mapping activities in Sweden in 2002. Field-work will be carried out in the area marked Gavle – southern Bothnian Sea (Gävle södra Bottenhavet) The other areas marked are in the process of
Figure A4.5 The plan of marine geological mapping activities in Sweden in 2002. Field-work will be carried out in the area marked Gavle–southern Bothnian Sea (Gävle– södra Bottenhavet). The other areas marked are in the process of interpretation of collected data.
46 2002 WGEXT Report
Figure A4.6 Areas surveyed by the Geological Survey of Sweden. Current state at the end of 2001.
2002 WGEXT Report 47
9 United Kingdom
Inshore seabed characterisation
The 2001 WGEXT report explained the aims of the work being undertaken by the British Geological Survey on the characterisation of the seabed in the Outer Thames Estuary (from the Deben Estuary to Dungeness), and the associated work with CEFAS on consideration of habitat classification systems and the potential use and application of geological data.
A further small 2-year follow-on project was undertaken in March 2000 by BGS and CEFAS, to consider the value and use of geological data in the mapping of marine habitats. Use has been made of existing geological and biological survey data from an area off the south coast of England (known as the Shoreham box) to identify relationships between biotopes and seabed facies.
The project is funded by DTLR. Reports on the three pieces of work will be published shortly.
10 United States of America
Mapping of offshore resources is done by the U.S. Geological Survey, often in cooperation with the Minerals Management Service or the U.S. Army Corps of Engineers (who have the responsibility for most beach nourishment projects). The impetus for mapping is now two-fold. Some mapping is done explicitly to identify sand resources for beach nourishment, but other mapping is being done to identify benthic habitats. Amendments to the Sustainable Fisheries Act in 1996 require the identification and protection of “Essential Fish Habitats” (EFH). EFH assessments are now required for essentially all projects even if an environmental impact statement (EIS) is not. Multibeam mapping systems and side-scan sonar are typically used in these studies. Examples can be found on the U.S. Geological Survey websites.
Marine resource mapping programmes publications
Gutierrez, B., Butman, B., and Blackwood, D.B. 2001. Photographs of the sea floor in western Massachusetts Bay: U.S. Geological Survey Open-File Report 00–427, CD-ROM. CD-ROM.
Hastings, M.E., Poppe, L.J., and Hathaway, J.C. 2000. Surficial sediment database, in Poppe, L.J., and Polloni, C.F., (Eds.). U.S. Geological Survey East-Coast Sediment Analysis-Procedures, Database, and Georeferenced Displays: U.S. Geological Survey Open-File Report 00–358, CD-Rom. CD-ROM.
Paskevich, V.F., Poppe, L.J., Hastings, M.E., and Hathaway, J.C. 2001. Sea-floor photography from the Continental Margin Program – a pictorial survey of benthic character and habitats along the U.S. East Coast: U.S. Geological Survey Open-File Report 01–154, CD-ROM. ONLINE.
Rendigs, R.R. and Bothner, M.H. Temporal changes in grain size and organic-mineral aggregate in surficial sediments near the Massachusetts Bay outfall site: U.S. Geological Survey Open-File Report 01–499. In press.
Schwab, W.C. Sand distribution on the inner shelf of Long Island, New York: U.S. Geological Survey Fact Sheet FS- 136–01. In press.
Valentine, P.C. 2001. Habitat geology studies on and near Georges Bank, off New England: U.S. Geological Fact Sheet FS-061–01, 2 p. ONLINE
Valentine, P.C., Malczyk, J., and Middleton, T.J. 2001. Benthic habitat and faunal surveys of closed Area II, central Georges Bank, 1998 and 1999: U.S. Geological Survey Open-File Report 01–066, CD-ROM.
Valentine, P.C., Middleton, T.J., and Fuller, S.J. 2001. Sea-floor maps showing topography, sun-illuminated topographic imagery, and backscatter intensity of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts: U.S. Geological Survey Open-File-Report 00–410, 1 CD-ROM.
48 2002 WGEXT Report
ANNEX 5: REVIEW OF DEVELOPMENTS IN NATIONAL AUTHORISATION AND ADMINISTRATIVE FRAMEWORK AND PROCEDURES
1 Belgium
The new law for sand and gravel extraction of 13 June 1969 was amended by the law of 20 January 1999 concerning the marine environment (“MMM-wet”) and by the law of 22 April 1999 concerning the exclusive economic zone (“EEZ-wet”). One of the most important consequences of these changes to the 1969 law is the fact that a concession can only be granted when the Minister of the Environment gives positive advice.
Also an “Advisory Committee” has been installed to ensure coordination between the administrators involved with the management of the exploration and exploitation of the continental shelf. One of the specific tasks of that commission consists of evaluating a 3-yearly review report with the results of the continuous research. The aforementioned Advisory Committee recently met in mid March 2002. A first draft of the review report was presented. Once accepted by the Commission, it can be presented to the group.
A proposal to change the extraction zones was also presented at the Committee. No decision has been taken yet, but the principal intention to do so was agreed upon. This will require a revision of the current legislation.
2 Canada
Canada proclaimed the Oceans Act in 1997, which recognises in domestic law Canada’s jurisdiction over its Maritime zones. It establishes authorities and responsibilities required to support Canada’s new oceans management regime. Under the Act, the Department of Fisheries and Oceans (DFO) is to lead the development and implementation of Canada's Ocean Strategy (COS) with the cooperation and collaboration of the 23 federal departments and agencies with oceans-related responsibilities. Based on three principles, precautionary approach, sustainable development and integrated management, COS will become a coordinated policy and decision-making process for oceans management.
The Oceans Act calls for a new approach to the management of Canada’s oceans based on an ecosystem approach, and calls for consideration of the impacts of all human activities on the respective ecosystem. The draft Policy and Operational Framework for Integrated Management (IM) recognises that management objectives and planning practices must reflect the fact that ecosystems nest within other ecosystems, and proposes that IM will extend from scales of Large Ocean Management Areas (LOMAs) to Coastal Community Planning Areas, with a range of connected and nested structures providing options for regional scales of response within this spectrum. Large-scale ecosystem- based management objectives are to be established through joint agreement among participants and used as management targets to guide the development of Integrated Management plans of various scales nested within a LOMA.
Although some elements of the COS (e.g., Marine Protected Areas Program) have commenced, DFO has yet to conduct a national consultation on the strategy. However, a number of regional meetings have been conducted based on area management under the LOMA concept. For the east coast of Canada, meetings were held on ESSIM, the Eastern Scotian Shelf Integrated Management area, to address stakeholder concerns and to formulate plans for moving forward on integrated management.
The Oceans Act will integrate all activities and the maintenance of ecosystem health will be paramount in decision making. Special areas termed “marine protected areas” (MPAs) will be given protection in the Act. Overall the objective is to strike a balance between maintaining sustainable marine ecosystems and the development of marine resources. The Oceans Act provides the context within which existing and future activities in, or affecting, marine ecosystems will occur. An offshore minerals industry has been identified as an emerging new oceans technology industry and will be represented at future discussions. Initiatives regarding marine mining will be assessed according to the guidelines and principles of the Oceans Act.
3 Denmark
The Forest and Nature Agency is, according to the Raw Materials Act, responsible for the administration of marine aggregate extraction in territorial waters and on the continental shelf.
A new Raw Materials Act came into force on 1 January 1997 (Consolidated Act No. 569 of June 30, 1997). Since this date all new dredging activities take place in permitted areas (Figure A5.1). A 10-year transitional period is allowed for dredging in 117 existing areas.
2002 WGEXT Report 49
New dredging areas are subjected to a Government View procedure including public and private involvement. The applicant is requested to provide sufficient documentation about the volume and quality of the resources in the area and to carry out an environmental impact assessment, (Executive Order, No. 1167 of 16th December 1996). Permits will be granted for a period of up to ten years.
Besides permits for dredging in specific areas, dredgers must have an authorisation to dredge in Danish Waters. In order to maintain a sustainable and environmentally justifiable dredging activity the total tonnage of the dredging fleet will be held on the present level.
Extraction activities, which can be assumed to have a significant impact on the environment, may be granted only on the basis of an assessment of the environmental consequences in accordance with the EC Directive 85/337. The procedure is laid down in Executive Order No. 126 of 4 March 1999. Dredging of more than 1 million m3 a year or 5 million m³ in total for a specific project or in a single area will always be subjected to this procedure.
The Danish Government has implemented “The Århus Convention of 1998 on Access to Information, Public Participation in Environmental Decision-making and Access to Justice in Environmental Matters” in the administration of marine extraction, Executive Order No. 835 of 4 September 2000. The Executive Order widens the public access to complain about decisions made by the authorities in accordance to the Raw Materials Act.
The process of converting the dredging area granted before from 1997 in accordance with the new Act started in 2002. The first permissions will be given in 2003. It is expected that up to 80 areas will be evaluated and receive a permission before 2007.
Figure A5.1 Dredging areas in Danish Waters, January 2001.
50 2002 WGEXT Report
4 France
Since 1997, the extraction of calcareous and siliceous aggregates comes under the same legal regulation. Applications are now beginning to arrive. The Ministry of Industry is responsible for administering new legislation, which is applicable to all areas of France.
Publication of the DUPILET, “Settlement of use conflict in the coastal zone between professional fisheries and others activities” report to the Prime Minister (April 2001)
The objective of this report was to propose solutions to prevent and minimise conflicts between fishermen and other users of the sea, including dredging companies. This report is based on talks with different national and local actors (professionals, local authorities, administrations, politics, technical and scientific organisations…).
For marine aggregate extraction, emphasis is laid on the necessary research of solutions on a European scale.
Propositions are made in order to:
• carry out an actualisation of marine resources and sensitive areas for fish (BRGM and IFREMER); • improve dialogue with fishermen; • set down regional extraction plans; • simplify administrative legal procedures; • set up reliable systems for an unquestionable control of the dredging activity.
Report in progress on the “Intercomparison of regulation procedures for extraction of marine sediments in some European ICES member countries”
This project is funded by the Ministry of Industry, which is responsible for preparing new legislation.
The objective is to see if and how the international recommendations (ICES guidelines) and the experience of traditional marine dredging countries (GB, NL, DK, B) can be applied in France where local conditions are quite different between the 3 main coastal areas (Channel, Atlantic, Mediterranean).
5 Ireland
No new legislation affecting the regulation of marine aggregate extraction was enacted.
6 The Netherlands
Although not yet fully implemented, there is a new approach to setting a threshold for EIA involving the volume of material extracted. Until now all extractions exceeding affecting an area of 500 hectare required an EIA. The intention is to add a criterion of 10 million cubic meters for extraction.
Due to an evaluation of the amended 1997 Sediment Extraction Act, over the last five years there are other changes foreseen. However, most of these changes will be related to terrestrial extraction. Another point of interest is the foreseen amendments to the Act regarding procedures. It is intended that the procedure for granting licences in the North Sea remains as brief as possible.
7 United Kingdom
The preparation of Regulations to introduce a statutory system of control over sand and gravel extraction from UK waters is ongoing. These will require dredging operators to obtain a Dredging Permission from the Secretary of State for Transport, Local Government and the Regions, to dredge in English waters, and from the relevant devolved administration for dredging in Welsh, Scottish or Northern Irish waters. They will replace the existing non-statutory Government View Procedure.
In parallel with preparation of the Regulations, DTLR has been developing a new policy framework for marine dredging in English waters. As reported in last year’s WGEXT report, a consultation document was issued in February
2002 WGEXT Report 51
2001. The guidance has been modified in the light of consultation responses and will be published in its final form shortly. It will apply both to applications for dredging licences made under the GV procedure and for Dredging Permissions made under the Regulations when they are introduced.
The National Assembly for Wales issued for public consultation a draft policy framework for dredging in the Bristol Channel (“Marine Aggregate Dredging Policy – South Wales”). Consultation responses are being considered.
52 2002 WGEXT Report
ANNEX 6: REVIEW OF APPROACHES TO ENVIRONMENTAL IMPACT ASSESSMENT AND RELATED ENVIRONMENTAL RESEARCH
1 Belgium
One of the implications of the changes to the law of 1969 is that an EIA should be made for every new application. The necessary legislation to enforce this requirement is under development. Meanwhile monitoring of existing extraction areas is ongoing.
Windfarms
EIAs for windfarms have recently been focusing on the possible effects of the windmills themselves on fisheries and the environment, rather than on the extraction activities necessary for the construction of those windmills.
Canada
Although no marine mining presently takes place in Canadian waters, harbour dredging and port maintenance continue to be a major activity. A large research project continues to assess the effects of dredge disposal in the Bay of Fundy off Saint John, New Brunswick. A variety of high-resolution seismic, side-scan, and multibeam bathymetric tools have been used and have identified slumping of the dredged muddy sediments into deeper water. Measurements of chemical concentrations and sediment transport have determined net movements of material to the west. Effects on the lobster fishery are being evaluated.
Other dredging assessment studies have been conducted in the Northumberland Strait to evaluate the disposal and attempted creation of new marine habitat from dredged material from the footings of the Confederation Bridge which was completed five years ago connecting Prince Edward Island to the mainland of Canada in New Brunswick. This connection is similar in engineering scope to the Øresund link in Europe. Multibeam bathymetry has been collected over the dredge disposal areas and reveals unique morphology to the spoils. Footings of the Confederation bridge have also been surveyed by multibeam bathymetric systems and show little infill despite sediment transport from west to east through the strait.
Cooperative projects to assess the effects of seabed trawling and clam dredging on seabed habitat are in the final stages of data assessment, interpretation and write-up. Some of these results can apply to potential seabed mining activities, as the technology is similar to that used in seabed mining. These projects are being conducted jointly between Fisheries and Oceans Canada and the Geological Survey of Canada. Results of these surveys will be a quantitative and qualitative assessment of the effects of bottom fishing gear on seabed alteration, biodiversity, community complexity and ecosystem reoccupation and recovery.
In order to effectively manage living marine resources in a sustainable fashion, a need exists to understand broader natural links between habitat and the fisheries. In the case of demersal fish, it is essential to understand how different life stages utilise benthic habitat and associated epibenthic organisms; what kinds of habitat are required to support them; how these habitats are spatially distributed; how much of these habitats is required to support sustainable fish communities, and how vulnerable these habitats or species associations are to human disturbance.
A new project was initiated in 2001 to define and map essential fish habitat on the Scotian Shelf within the Eastern Scotian Shelf Integrated Management (ESSIM) area, primarily within the boundaries of an area closed to mobile groundfish gear since 1987 and in adjacent fished areas. 2001 was a pilot study year of a potential 3-year project. The dominant demersal fish species in this area is haddock, but cod and various flatfish species are also abundant. Upon completion of the 2001 pilot study, a formal proposal was put forth for funding and as of March 2002 has been approved, but at a slightly lower funding level.
This 3-year long-term program will address four basic hypotheses:
• The physical and biological characteristics of benthic habitat display pronounced spatial variability on the Scotian Shelf. • Undisturbed benthic habitat plays an essential role in the life histories of demersal fish. • The characteristics of essential fish habitat for different species of demersal fish can be defined, measured and mapped.
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• Essential fish habitat needs protection from human disturbance in order to maintain the biodiversity and productive capacity of marine ecosystems and sustainable fisheries.
The study will be conducted by a multidisciplinary team of geologists, engineers, benthic ecologists, fisheries ecologists and ecosystem modellers.
A one-year pilot project was undertaken in 2001 and the field programme used a QTC (Quester Tangent Corporation) seabed acoustic characterisation system with high-resolution fish detection acoustic systems. These were integrated with sidescan sonar, bottom samples and video and tested at numerous locations on the Scotian Shelf.
One of the important experiments was to evaluate the ability of the QTC seabed characterisation system to characterise and differentiate the variety of benthic habitats in comparison with high-resolution side-scan sonar data. This is still a matter of debate between marine biologists and geologists for low-relief continental shelf habitats. The evaluation included processing groundtruth data, either already available or collected during the cruise. Preliminary field evaluation indicates that the QTC system has difficulty in discriminating variance within gravel areas and identifying individual boulders and fields of boulders of importance to demersal fish. Major sediment boundaries were however, recognised. Evaluation of the data is continuing.
3 Denmark
In Denmark the National Forest and Nature Agency is responsible for the administration of marine aggregate dredging.
All new licensed areas are subjected to a Government View Procedure including public and private involvement.
3.1 Recent Environmental Impact Studies
The Harbour of Århus
A major enlargement of the harbour of Århus has required dredging of 8 million m³ of sand fill. Based on prospecting carried out by the Harbour, two areas in the Århus Bight were selected for dredging. Due to the size of the project the Harbour was requested to carry out an environmental impact assessment in accordance with the EC Directive 85/337 as part of the application. Based on the assessments acceptable spill limits were set to 6 % and 7 % respectively. The spill should be measured every 10th cargo. Besides that, the Harbour has set up a monitoring programme to ensure that the environmental impacts are within the limits stated in the permission.
Results from monitoring of the bottom fauna after dredging of approximately 8 million m³ of sand show that the changes outside the dredging areas are very small and of the same magnitude as in the reference area. The results in both the impact area and the reference area show a significant and parallel increase in the number and abundance of species (Århus Havn, 2000).
The Harbour of Århus is preparing a new EIA for dredging up to 7 million m³ of sand fill for a further enlargement of the harbour. The sand fill will be dredged from three areas in the Bay of Århus. Two of the areas have been used in the first part of the project. The EIA was published during 2001.
Stigsnæs
An Environmental Impact Assessment in accordance with the EC Directive 85/337 was recently been carried out in 2000 for a proposal to construct a Container Terminal Hub near Stigsnæs, Western Zealand. The project includes dredging of 5.6 million m³ of sand fill in a very environmentally sensitive area. To fulfil the environmental requirements, direct pumping from the dredging site and use of sedimentation basins is expected to be necessary (The Baltic Gate Terminal A/S, 2000).
North Sea
The Danish Coastal Authority (DCA) has applied for 4 new dredging areas in the North Sea to be used for dredging of sand for beach nourishment in the next 10 years. The application covers dredging of up to 30 million m³. The application is based on an Environmental Impact Assessment in accordance with the EC Directive 85/337 (Kystinspektoratet, 2000).
54 2002 WGEXT Report
Marine Windmill Parks
Environmental Impact Assessments for dredging operations necessary for the construction of marine windmill parks have been carried out for parks on Horns Rev in the North Sea, South of the island of Læsø and in the Femer Belt.
3.2 Research Projects
Impact from dredge spill on benthos
The Forest and Nature Agency has initiated a research project on the impact of dredge spill on benthos in cooperation with the National Environmental Research Institute. A detailed study of the ecological consequences of dredging in coarse sediments started in 1996.
Studies on the effects of the exploitation of marine resources on epifauna suspension-feeders have recently been published (Lisberg et al., 2002).
Development of new methods for low cost screening of biological interests in potential dredging area
The Danish Forest and Nature Agency (DFNA) has commissioned Hedeselskabet to investigate different methods for screening of biological interests in proposed dredging areas.
The purpose of the study is to evaluate different seismic and diver techniques in order to develop reliable low cost screening methods for identification of the most important benthic flora and fauna communities.
The study (DFNA 2002) shows that paravane diving may be a cost-efficient method to identify and demarcate benthic flora and fauna communities. The result of the screening will be the basis for decisions on the scope of investigations to be carried out in connection with an application for dredging permission. In a number of cases the screening will be a sufficient background for an impact assessment.
Emissions from Dredgers
A study (in Danish) of the energy consumption and emissions from dredging and transport of marine and land-based resources was finished in 2000.
Statistics
The Danish Forest and Nature Agency has completed a study on the use of statistical analyses in environmental monitoring of dredging spill. The study describes the theoretical background and gives a number of examples of the use of statistics for setting up administrative requirements and for evaluation of the necessary number of measurements for obtaining a specified uncertainty/variation of the considered parameter (Skov- og Naturstyrelsen 1999).
Environmental effects of dredging in the North Sea
The Forest and Nature Agency and the Coastal Protection Agency have initiated a monitoring programme off the West Coast of Jutland to study the effects of dredging of sand for beach protection.
The study is based on a comparison with simultaneous changes in a reference area. The post-nourish temporal development is analysed using the BACI concept (B(efore) A(fter) C(omparison) I(impact)). A complete quantitative recovery including the number of species, the abundance and the biomass of the bottom has occurred in less than one year after the sand extraction. However, the predominance of a supposed opportunistic species of polychaete (Spio filicornis) in the borrow area may indicate a pioneer recolonisation. The impact of sand extraction on the predator populations is limited due to a patchy exploitation pattern leaving plenty of foods in 70 % of the (undisturbed) bottom and a recovery of the benthic biomass in less than one year.
Effects of exploitation of marine resources on epifaunal suspension-feeders
The purpose of this project is to demonstrate and assess potential effects of suspended and settled material on selected benthic suspension-feeders due to exploitation or other digging activities in the seabed. The focus is on suspension-
2002 WGEXT Report 55
feeders from hard substrata habitats, as it is assumed that they are rarely exposed to high loads of suspended material and thus are less tolerant compared to the soft bottom fauna.
In 1996 NERI, in collaboration with the Danish Forest and Nature Agency, DFNA (Skov- og Naturstyrelsen), and the Geological Survey of Denmark and Greenland (GEUS), measured concentrations of suspended material in wastewater and from several positions downstream from a vessel collecting pebbles. The results from these measurements and the present study are integrated in the discussion.
3.3 Recent Literature and Reports
Anthony, D., and Leth, J.O. 2002. Large-scale bedforms, sediment distribution and sand mobility in the eastern North Sea – off the Danish west coast. Marine Geology (in press).
The Baltic Gate Terminal A/S. 2000. Environmental Impact Assessment for Dredging of Sand for The Baltic Gate Terminal. Report prepared for The Baltic Gate Terminal A/S by GEUS in cooperation with Carl Bro A/S and Bioconsult A/S. (in Danish).
GEUS. 1999. Treasures hiding in the Sea. Marine raw material and Nature Interests. An evaluation by GEUS and The Danish Forest and Nature Agency. Geological Survey of Denmark and Greenland, 1999, 20 p.
GEUS. 2000. Digital Sea Bottom Sediment Map around Denmark. The Geological survey of Denmark and Greenland, 2000/68.
Kystinspektoratet (Danish Coastal Authority), 2000. Environmental Impact Assessment for dredging areas for sand on the West Coast, November 2000. In Danish.
Leth, J. O., Anthony, D., Larsen, B., Andersen, L. T., and Jensen, J. B. 2001. Geological mapping of the West Coast. (In Danish). Prepared for Danish Coastal Authority (DCA) 1998 – 2001. GEUS report 2001/111, 2001.
Lisberg, D., Petersen, J.K., and Dahl, C. 2002. Effects of excavations for natural resources on Benthic Epifauna. National Environmental Research Institute, (English abstract). Biologiske effekter af råstofindvinding på epifauna. Danmarks Miljøundersøgelser. 56 s. – Faglig rapport fra DMU nr. 391. http://faglige-rapporter.dmu.dk
Ministry of the Environment and Energy. 2000. 10th Semi-Annual Report on the Environment and the Øresund Fixed Link´s Coast to Coast Installation. 2000.
Ministry of the Environment and Energy. 2000: Executive Order No. 835 of 4. September 2000 on the Information of legitimate complainants on decisions in cases about marine extraction.
Skov- og Naturstyrelsen. 1999. Måleomfang og usikkerhed – tilfældige fejl. Rapport udarbejdet for Skov- og Naturstyrelsen af Rambøl. English abstract: Statistic – a Tool to Control Requirements. Prepared for National Forest and Nature Agency by Christensen, C. F., Rambøll, 2000.
Skov- og Naturstyrelsen. 2000. Extraction of aggregates, Energy consumption and Emission. http://www.sns.dk/raastof/baeredygtig.htm. In Danish.
Skov- og Naturstyrelsen. 2002. Karrebaeksminde, Biological screening of extraction area for pebbles- and sand suction by dive and sonar (English abstract). Prepared for Danish Forest and Nature Agency by Hedeselskabet 2002.
WaterConsult. 1997. The Fixed Link across Øresund. Spill Monitoring at Reclamation of Sand at Kriegers Flak for use at the Fixed Link across Øresund. Report prepared for National Forest and Nature Agency and Øresundskonsortiet by Water Consult.
Øresundskonsortiet. 2000. Dredging on Kriegers Flak. Sediment spill. Final report, March 2000. Report prepared for Øresundskonsortiet by WaterConsult. (In Danish).
Øresundskonsortiet. 2000. Environmental Impact of the Construction of the Øresund Fixed Link. May 2000.
56 2002 WGEXT Report
Århus Havn. 2000. Marinbiologiske undersøgelser. Råstofindvinding, Århus Havn 1999. (Abstract in English: Marine Biological Investigations, Dredging of Sand).
4 France
4.1 Impact of Sand Pits on Bottom Morphology in Shallow Water
One of IFREMER’s roles is to assess the validity of environmental impact studies carried out by industrial companies when submitting their permit applications. In order to improve its expertise (and possibly refine the requirements of the environmental impact assessment), IFREMER has initiated a research programme aimed at better understanding the impact of sandpits on the bottom morphology in shallow water. The programme, funded by IFREMER, began in 2001 and is expected to last five years.
Sand mining in coastal regions is subjected to different regulations throughout the world. While a minimum water depth is commonly used as a restrictive criterion for providing mining licenses in numerous countries, no such limit is used in France. As a result, extractions may very well be carried out in shallow areas where wave propagation might be altered by the sandpit. In a general erosional context of sandy coasts, such practices are often held responsible for beach recession.
While monitoring of extraction sites is now required and can help us understand how the morphology of sand pits evolves depending on the local physical processes (waves, currents, geometric characteristics of the pit, bottom slope, sediment size, etc.), we need to be able to predict long-term evolutions in order to reduce negative impacts due to poor coastal management.
After several physical models had been used to study the effects of sand pits in a wave tank (e.g., Migniot and Viguier, 1983), numerical models became available to understand quantitatively, at a lower cost and for a variety of configurations, how the different physical parameters interact in long-term morphological evolutions. So-called morphodynamic models include a hydrodynamic module (to compute tidal currents coupled with waves), and a sediment transport module, as they update the bottom in time. However, long-term simulations still require representative conditions for the wave climate and the tidal regime to be chosen, as high computational times restrict the simulation of a realistic succession of tides superimposed with the random occurrences of waves that occurred over the years. Depending on the case, the results of the simulations might be highly dependent on this input schematisation, as well as on the transport formula.
In order to tackle one problem at a time, we decided to first test the ability of a state-of-the-art morphodynamic model to reproduce morphological evolutions monitored in a wave tank (Migniot and Viguier’s experiments, 1983). Simultaneously, we will apply the model to a real site for which morphological evolutions have been monitored over fifteen years, in order to compare observed evolutions with modelled hind-cast predictions.
It is probably beyond the scope of an environmental impact study to routinely run such models. The ultimate goal of our study would therefore be to establish a methodological guide based on simulations run on different environments (different wave climates, sediment types, bottom slopes, etc.) in order to define a number of indicators to be investigated within an environmental impact study, along with accepted values for these indicators.
4.2 REBENT Study
A study named REBENT (for “Réseau Benthos”) was begun in 2001 over coastal waters of Brittany as a pilot-area. It concerns a new survey network of the macrobenthos in relation to oil pollution and long-term climate change.
The main partners undertaking the research project are IFREMER and the European Université Institute of the Sea (Brest). The Project is being funded by the Territorial Assemblies of Brittany, DIREN and other scientific organisations.
The first step will be targeted towards intertidal areas and inshore waters (max. depth 30 m) in relation to the EC Water Directive. This work will use maps to synthesise information about morphosedimentology, the main habitats, algal cover, etc., providing a zonal approach of the seabed in relation to the main abiotic factors.
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Two others aims will be developed:
• spatial evolution of some local and characterised habitats and populations; • long-term survey of reference stations selected according to their representative features, interest and sensitivity.
This new benthic survey will be described in the frame of the 2002 Working Group on Marine Habitat Mapping (WGMHM) report, but it is also relevant for WGEXT because such a study will have to be developed for the Eastern Channel using similar methodology. This will improve scientific capacity for assessment of the effects of dredging on benthos and the seabed.
4.3 Dieppe Case Study: Monitoring of impact since 1980
After a first sampling survey in the eastern deposition area in 1999 (see WGEXT report 2000), the whole control area was sampled in May 2001 (19 stations; Figure A6.1, below) around the two extraction sites:
• Graves de Mer: 6 km²; 280,000 t in 2000; • Gris Nez: 0.5 km²; 100,000 t in 2000.
Aims of the survey:
• impact of extraction (stations 7, 9, 11, 13, 15) • impact of oversanding (stations 8, 12, 14, 16, 17, 18, 19) • recolonisation rate (stations 3, 4, 5, 6, 10).
Initial findings:
• the negative impact of oversanding (dominance of fine sands, high percent of very fine sand) is at least equivalent to that of dredging in the direction of prevailing currents (observed east of both extraction sites); • a positive impact of these deposits from overflow (very fine sands) can be detected in the immediate vicinity (100 m) of the second extraction site, perpendicular to the main tidal currents (sea- and land-wards); • seven years after the cessation of dredging activity, recolonisation was achieved in 4/5 of the former extraction site (st 6), except in the easternmost part (st 10) where a cumulative impact (through oversanding from the second extraction site) may have prevented any recolonisation.
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Figure A6.1 The locations of the 19 stations sampled in the Dieppe case study.
A quantification of the impact gives the following results for the three primary variables:
Table A6.1 Impact intensity for the three primary variables.
Impact Intensity Reference Positive Moderate Maximal area impact negative negative Taxa 42 65 31 19 Abundance m−² 1100 3200 600 285 Biomass (g m−²) 18 15 18 5
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• the nature of benthic communities is closely linked to sediment characteristics: • reference medium sands are characterised by Amphioxus, the sea-urchin Echinocyamus, the bivalve Glycymeris, and by worms (Notomastus and Syllidae); • heterogeneous sediments of the surrounding area are characterised by the worms Pomatoceros and Lumbrineris and by the sea-urchin Echinocyamus; • fine sands of the deposition area are characterised by the molluscs Spisula, Ensis and Dentalium, the worms Nephtys and Spiophanes, and the sea urchin Echinocardium; • pebbles and gravels within and around the extraction area are dominated by few epifaunal species like the barnacle Balanus, encrusting bryozoans and the sessile worm Pomatoceros, accompanied by the decapod Galathea, the gastropod Crepidula, the soft coral Alcyonium and sea anemones. All these findings are in agreement with previous data on this site (Desprez, 2000) and similar sites like in Hastings (CEFAS, 2001). The research for this project was undertaken by GEMEL and funded by dredging companies.
4.4 Impact of Marine Aggregate Extraction
The project began in 2002 and is expected to continue until 2006.
A description of the main topics of this project was given in the 2001 report; objectives for 2002 are the following:
• fortnightly monitoring of fish (identification, counting, biomass and biometry) in the extraction site and the surrounding areas (intensive deposit area, recolonisation and reference ones); • trophic relationships between benthic and demersal fish species and benthic preys through analysis of stomach contents; • continuation of the restoration process of the former extraction site (cessation of activity in 1995); • video “ground-truthing” survey of the different areas (underwater video records with divers and sledge).
The organisation undertaking the research is a scientific interest group, the funding bodies include The Ministry of Research, Region Haute-Normandie and dredging companies, with the collaboration of IFREMER and Universities (Rouen, Le Havre).
5 Ireland
As indicated in the Strategy Statement 2001–2003 of the Department of the Marine and Natural Resources, a Strategic Study is proposed in order to help determine national policy in relation to the question of whether or not to allow commercial extraction of offshore sand/gravel deposits. Pending the completion of that study, which will, inter alia, review data generated by the ongoing national Seabed Survey being conducted by the Geological Survey of Ireland, licenses are not being granted for commercial extraction of offshore sand/gravel deposits. Any licensing regime which may emerge will be likely to require full Environmental Impact Assessment of any extraction proposed.
6 The Netherlands
6.1 Punaise *3 Project
In the winter of 1996 beach nourishment was executed at the central Dutch coast near Heemskerk/Wijk aan Zee, using a temporary borrow pit located in front of the beach at a water depth of 7 m. After the beach nourishment was completed, the pit was refilled with sand from deeper waters. Between 1996 and 1998 the benthic community was monitored in order to study the ecological recovery of the area after the borrow pit was refilled with sands. It was concluded that after 15 months the benthic fauna had largely recovered but differences between the former borrow pit and its surroundings were still present in terms of community structure, density and biomass. In 2001 a final survey was undertaken. Four years after completion of the dredging activities the former borrow pit could not be distinguished any more from the surrounding area. The benthic community had recovered completely and showed great resemblance to the community present at the starting point in 1996. It was concluded that in a highly dynamic environment such as this, the top layer of sediment recovers within about 1 year, but it takes four years to have a complete recovery of the benthic community.
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Stress: 0.18
Pit Reference
May 1996
Febr 1997
May 1997
April 1998
June 2001
Figure A6.2 MDS-configuration of benthic species abundance data (√√-transformed, Bray-Curtis similarities) from four successive sampling surveys before (1996) and after refill of the borrow pit (1997–2001) at Heemskerk/Wijk aan Zee.
References
Van Dalfsen, J.A., Duijts, O. W. M., and Storm, B. 1999. Effecten op de bodemfauna van het gebruik van een tijdelijke zandwin/overslagput in de kustzone ter hoogte van Heemskerk. Punaise*2. Koeman en Bijkerk, Rapport 99–13.
Van Dalfsen, J.A., and Lewis, W. E. 2001. Punaise*3. Lange-termijneffecten op de bodemfauna van een tijdelijke zandwin/overslagput in de kustzone ter hoogte van Heemskerk. Punaise*2. TNO-rapport R 2001/494
6.2 EIA for the extraction of aggregate sand from the North Sea. A study of the effects in the area off the coast of South-Holland
The starting document for this project was produced in September 1998, the second public draft is expected in July 2002. The project is expected to run until December 2002.
The organisations undertaking the research are The Netherlands Ministry of Transport, Public Works and Water Management, the Directorate of the North Sea. and The National Institute for Coastal and Marine Management (RIKZ). The funding bodies consist of The Netherlands Ministry of Transport, Public Works and Water Management and the Directorate of the North Sea.
The study has a general character and is focused on the environmental impact of the extraction of a maximum of 40 million tonnes of aggregate sand from a depth of 5 to 30 metres below the seabed. Particular attention is given to the handling of the cover layer of lower quality sand. Proposals for large-scale extraction must be accompanied by an EIA that is more specific than this general EIA. The project covers the Netherlands Continental Shelf, blocks P12, 14 –18, Q10, 11, 13, 14, 16, S1, 2, 3, 5, 6.
6.3 EIA for the extraction of aggregate sand and gravel from the Cleaverbank Area
The starting document was produced in July 2001, the guideline EIA in October 2001. The EIA is expected to be published in August 2002 as a public draft. The project is expected to run until December 2002.
The organisations undertaking the research are The Netherlands Ministry of Transport (Initiator), Public Works and Water Management, The Directorate North Sea and Royal Haskoning, Haskoning Nederland b.v.
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(Drafter). The funding bodies consist of The Netherlands Ministry of Transport, Public Works and Water Management and The Directorate of the North Sea
The study is focused on the environmental impact of the extraction of an amount of about 20 million cubic metres of aggregate sand and gravel from the Cleaverbank Area (Netherlands Continental Shelf, blocks D15, 18, E13, 14, 16, 17, J3, 6, K1, 2, 4, 5). Due to the coarse sediments on the seabed the benthic fauna in this area is special compared to the other parts of the Dutch Continental Shelf. The EIA is aimed at defining locations for the extraction and extraction methods in such a way that recovery of the benthic fauna is possible. Extraction in the Cleaverbank Area is compared with extraction in the area off the coast of South-Holland.
6.4 EIA for the extraction of sand for the Westerschelde Container Terminal in the southern part of the North Sea
The starting document for this project was produced in October 2001, the guideline EIA in February 2002. The first public draft is expected in July 2002. The project is expected to run until December 2002.
The research was commissioned by Zeeland Seaports and prepared by DHV Milieu en Infrastructuur BV. The funding bodies consist of Zeeland Seaports.
The study is focused on the environmental impact of the extraction of an amount of about 20 million cubic metres of fill sand in the area off the coast of Zeeland from the 20 m depth contour (Dutch Level) to a distance of 40 km from the coast.
Alternatives are given by location and by shallow (<2 m below the seabed) versus deep (> 2 m) extraction.
6.5 PUTMOR
The organisations undertaking the research are The National Institute for Coastal and Marine Management (RIKZ), the Netherlands Ministry of Transport, Public Works and Water Management and the Directorate of the North Sea. The funding bodies consist of the Netherlands Ministry of Transport, Public Works and Water Management and the Directorate of the North Sea.
Field measurements were carried out in and outside a large extraction pit some 10 km off the Dutch coast near Hoek van Holland. The dimensions of the pit are 500 m × 1300 m, with a depth of 10 m relative to the seabed. The water depth is 22–24 metres.
After the measurement period the pit was filled in with harbour mud.
The aim of the study is to determine changes in physical parameters due to the presence of an extraction pit. The physical parameters are important to qualify and to quantify the morphological and ecological effects of sand extraction pits. The field study can be used for validation of models on hydrodynamics and morphology. The study shows that the influence of the sand pit on the flow velocities is generally small. The flow velocities in the pit are sufficient to renew the water each tide even in the lower parts. Therefore there in no increase of stratification. There is no indication that the pit acts as a trap for water with high density. Occasionally the oxygen content is measured. These measurements show only a slight difference (< 0.2 mg/l) between a location at the bottom of the pit and at the seabed near the pit.
The morphological development of the sand pit during the observation period is less than the accuracy of the bathymetric surveys.
The measurements comprise bathymetry, flow velocities, water levels, temperature, conductivity, turbidity, oxygen content and analysis of seabed sediments.
The validated data of the measuring campaign will be available on CD-ROM in December 2002. This project was initiated in January 1999 and is expected to last 4 years.
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The following reports have been published:
Hoogewoning, S. 2000. PUTMOR-field measurements. A six-months measuring campaign at a lowered dumping pit near Hoek van Holland (The Netherlands). Work document RIKZ/OS-2000.132x. National Institute for Coastal and Marine Management (RIKZ), Den Haag, 27 p.
Svasek. 2001. PUTMOR field measurements at a temporary sand pit, part 1: processing and validation. Kust2005 Report, National Institute for Coastal and Marine Management (RIKZ), Den Haag / Svasek, Rotterdam.
Svasek. 2001. PUTMOR field measurements at a temporary sand pit, part 2: data analysis. Kust2005 Report, National Institute for Coastal and Marine Management (RIKZ), Den Haag / Svasek, Rotterdam.
Svasek..2001. PUTMOR field measurements at a temporary sand pit, part 3: final report. Kust2005 Report, National Institute for Coastal and Marine Management (RIKZ), Den Haag / Svasek, Rotterdam.
6.6 Map of archaeological and cultural heritage values on the Netherlands Continental Shelf
The research is being undertaken by The Netherlands Institute for Maritime and Underwater Archaeology. The funding bodies consist of the Netherlands Ministry of Transport, Public Works and Water Management and The Directorate of the North Sea.
As a result of the framework of the Malta Treaty and the UNESCO Convention on Underwater Cultural Heritage, the importance of archaeological and cultural heritage values in planning extraction activities is increasing. Therefore, an archaeological expectation map has been made that gives an indication of the areas with a high chance of finding archaeological and cultural heritage values in the seabed. This map is based on the geomorphological behaviour of the seabed.
Another map has been made that gives the location of archaeological remains, mainly wrecks.
The two maps will be combined to produce one map of archaeological and cultural heritage values on the Netherlands Continental Shelf. This project was initiated in 1999 and a map is expected to be produced in 2002.
6.7 Map of geomorphological and geological values on the Netherlands Continental Shelf
The research is being undertaken by The Bureau Buitenwerk, Deventer and is being funded by the Netherlands Ministry of Transport, Public Works and Water Management and The Directorate North Sea.
Geomorphological and geological values are being more and more taken into account in the decisions about the location of extraction sites. In EIAs they must be described. Therefore, a map has been made of areas with geomorphological and geological values on the Netherlands Continental Shelf. This map is based on the notion that it is worthwhile to preserve good examples of geomorphological or geological features from each period of the Quaternary. Both important features on the seabed as well as boreholes or areas of seismic lines with unique stratigraphic information are mapped. This project was initiated in 1999 and a map is expected to be produced in 2002.
6.8 Kust*2005 Zeebodem
The research is being undertaken by The National Institute for Coastal and Marine Management (RIKZ) and Den Haag. The project is being funded by The Netherlands Ministry of Transport, Public Works and Water Management and The Directorate of the North Sea (among others).
The project is focused on the effects of (large-scale) extraction of sand in relation to the licence conditions.
The end products will be:
1. interpretation of the PUTMOR Project; 2. physical effects of large scale-sand extraction; 3. effects of sand extraction on sand banks.
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The project commenced in 2001 and is expected to be completed in 2004.
6.9 BEAST
The project started in 2001 and aims to integrate present knowledge and site-specific information in order to understand and predict the possible environmental impacts of different human activities. Ecotope maps will be produced on a scale that is applicable for detailed EIA studies. Using GIS, a tool is to be developed to support the management of different human activities on the Dutch Continental Shelf that might affect the seabed.
6.10 Ecomorphodynamics of the North Sea
The project started in 2000 and will be reviewed annually. To improve management opportunities and use of the North Sea, field management and knowledge of the ecomorphodynamics have to be integrated. The project aims to improve knowledge on the relationship between different natural processes affecting benthic life. Seabed characteristics (morphology, sedimentology), dynamics and benthic life (including benthic fish) are studied using different techniques, including side-scan sonar, multibeam bathymetry and bottom sampling. First results from 2001 indicate distinct differences between benthic species composition and morphological features such as sand, wave crests and troughs being independent of area and sampling period.
References
Deflt Cluster, Ecomorphodynamics of the seafloor, Baptist et al. 2001. Progress Report 2000. Website: www.delftcluster.nl/index
6.11 The Flyland-project
In 1999, the Dutch government decided that the construction of an airport on an island in the sea could not be excluded for the future. Therefore funds were made available to start a research programme. The total programme is split into eight topics. The relevant theme “marine ecology and morphology” began in 2000 and will end in 2004. The research programme of this theme is split into two phases, the first ended in October 2001. During the first stage present knowledge was gathered and uncertainties were inventoried for different perspectives: water movement, mud transport, (phyto) plankton, the benthos community, beach and dune ecosystems, fish fauna, birds and seals. The work is done by a consortium (named “MARE”) of national research institutes: Delft Hydraulics (WL), Netherlands Institute of Applied Geoscience (NITG-TNO), Netherlands Institute for Sea Research (NIOZ), Green World Research (Alterra), Netherlands Institute of Fisheries Research (RIVO) and a separate party for birds and seals (Alkyon-Waardenburg)
Five island scenarios (all between 13 to 30 km off coast and 6400 to 8100 ha in size) in combination with two different sand extraction sites were used to cover all possible effects. Sand extraction is located outside the 20 m depth contour and will lower the seabed an additional 20 m. A matrix of effects was conducted for several target species (fish, birds and seals) and groups of users (e.g., recreation, fisheries, coastal safety). Estimated effects (during and after the building) were compared to the zero situations in which the sea-level rises, opening of the Haringvliet sluices, the second Maasvlakte is build, a nearshore windmill park near Egmond is in production and fishery is reduced for 25 % and nutrients load are further reduced. The effect of the Haringvliet sluices and the building of the second Maasvlakte for instance are believed to have a large influence on the algae. The effects of all these developments are believed to have a large impact on the ecosystem at a comparable scale as the island alternatives.
Phase 1 nominated a number of effect-chains that could lead to possible go or no-go management decisions:
• The mud plume present during the building phase (both from the extraction site and from the island site) is regarded as a highly relevant topic in assessing the environmental impact. If 10 % of the mud present at the extraction site will come into the water, effects will be small. Whereas, in the worst case scenario, if 100 % of the mud content present will come in the water, the mud content of the North Sea waters will increase with 200–700 %. This will negatively influence the light conditions necessary for the growth of algae. How this will influence higher tropical levels in uncertain. Modelling shows also higher mud content for the waters in the Wadden Sea (200 %). For the German Bight a possible Phaeocystis bloom is predicted. • The possible working of the extraction site as a sink for organisms, with special reference to the transport mechanism of fish larvae to nursery areas. A hydrodynamical aspect of an island is a strength reduction of the coastal-directed component of the residual current. This will cause a delay in transport of fish larvae to their nursery areas. The implications for fish production and fishery are unknown.
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The presence of an island will split and broaden the “coastal river”. The mud content of the coastal water (the first 10 km) will decrease, whereas in the 10–20 km zone the mud content of the waters will increase. Algal blooms will increase in the coastal waters. In the outer area (20–30 km) the nutrient availability will increase. There is uncertainty in how these changes will work through the food chain (e.g., zooplankton – fish-fishery).
The second phase is still in the negotiation phase, except for some already funded fieldwork. The emphasis will be on the uncertainty in the mud content of the extraction sites and the possible effects of the plume up to the higher trophic levels. Hydro-dynamical modelling will be refined and different scenarios of the transportation of demersal fish larvae are modelled. Field data on fish and benthos abundance will be used to work on habitat modelling as a prediction tool for assessing the impact.
A relevant report (in Dutch):
Grift, R.E., Welleman, H.C., Rijnsdorp, A.D. en H.W. van der Veer, 2001. De visgemeenschap en de visserij in het Nederlandse kustgebied en de Westelijke Waddenzee. Fase 1. RIVO Rapport C047/01.
6.12 Quantifying the effects of infra-structural works on brown shrimp populations: A habitat modelling approach
This work is funded by “Flyland” and is an element of the first phase of the benthos research in order to assess ecological and morphological effects of a possible new airport on an island situated in the coastal zone. The brown shrimp (Crangon crangon L.) is one of the key species in the coastal ecosystem in the southern North Sea. Years of autumn survey catches were analysed in combination with environmental information for the catch location (sediment characteristics, chlorophyll, salinity, temperature and depth). GLM analysis showed that catch variability decreased significantly with depth and salinity, whereas sediment characteristics or chlorophyll are much less important. A simple model including depth and salinity (data were obtained from NITG-TNO and WL) is used to estimate shrimp abundance in the Dutch coastal zone and Wadden Sea. Results indicate that these two environmental factors explain 49 % of the variation in shrimp catches. The fitted relationship between salinity, depth and shrimp abundance is visualised for the whole coastal zone based on a grid map with salinity values and a contour map of depth. The map allows predictions to be made about the direct effects of infra-structural works like an artificial island off the Dutch coast. Results also indicate the need to consider the risk that environmental parameters like salinity and depth are permanently altered over larger areas.
Relevant report (in Dutch):
Welleman, H.C., 2001. Een beschrijving en GIS modellering van het garnalenbestand (Crangon crangon) voor de Nederlandse kust. RIVO rapport C057/01.
7 United Kingdom
7.1 Southern North Sea Transport Study Phase 2
This two-year research project is due to finish in July/August 2002. It is being funded by the Department of the Environment, Food and Rural Affairs, English Nature, Anglian Coastal Authority Group, Humber Estuary Coastal Authority Group, The Crown Estate, and the British Marine Aggregate Producers Association.
Hydraulics Research Wallingford is leading the consultancy team, which includes The Centre for Environment, Fisheries and Aquaculture Science, University of East Anglia, Posford Haskoning and consultant Brian d’Olier.
The purpose of this research is to improve understanding of the southern North Sea sediment transport system and its impact on the eastern English coastline between Flamborough Head and the River Thames. The information being obtained includes sediment sources, transport pathways, volume of sediment, areas of deposition and offshore features.
Phase 1 of the project was completed in 1996. It included a literature review, the creation of a database and the creation of a concept for a sediment transport model. Phase 2 will address the gaps in information identified in Phase 1; it will update the database and amend the transport model to take account of further information provided since Phase 1.
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7.2 Marine Life Information Network (MarLIN)
This project is being conducted by the Marine Biological Association of the UK on behalf of ABP Research and Consultancy, Countryside Council for Wales, Joint Nature Conservancy Council, Department for the Environment, Food and Rural Affairs, English Nature, The Environment Agency, Scottish Natural Heritage and The Crown Estate. The objectives of the study include:
• the identification of sources of marine biological data and to access, grade and use that data to identify distributions of biotopes and species; • the development of a network of data access for collaborators in the programme.
The first three years of the project have achieved their main objectives, particularly for the Seabed Data Acquisition and Interpretation Biology and Sensitive Key Information Sub-Programmes. The operational phase for the next three years will soon be under way aiming to build on what has already been achieved and develop the information resource and web-based tools to meet the needs of the users of MarLIN.
7.3 Marine Biodiversity and Climate Change (MarClim)
The MarClim project is coordinated by the Marine Biological Association in Plymouth and includes an extensive list of Government, Research, Conservation, Non-Governmental and Public Bodies in England, Scotland, Wales and the Republic of Ireland. The project started in April 2001 and it will run for four years.
The project is using novel synthesis of existing long-term data on temperature-sensitive, readily observed intertidal climate indicator species to make predictions on changes in coastal diversity that may result from global warming. The species investigated include Bifucaria bifucaria, Chthamalus montagui, Gibbula umbilicalis, Semibalanus balanoides, Fucus serratus, Osilinus lineatus and Patella vulgata.
Aims:
• To use a combination of archival and contemporary data to develop and test hypotheses on the impact of climate change on rocky intertidal animals and plants. • Forecast future community changes based on climate models. • Establish a low-cost fit-for-purpose network to enable regular updates of climatic impact projections. • Assess and report likely consequences of predicted changes on coastal ecosystems. • To provide general contextual time-series data to support marine management and monitoring. • Evaluate use of intertidal indicator species as sustainability indices. • Disseminate the results as widely as possible. • Provide a basis for the development of a pan- European monitoring network.
7.4 An Investigation of the Potential for Cumulative Environmental Effects Arising from Marine Aggregate Extraction
This is a 4-year study being conducted by CEFAS on behalf of the Department of the Environment, Food and Rural Affairs (DEFRA). The final report is due for completion at end of April 2002. The objective of the study is to distinguish natural changes from dredging-induced changes to allow scientific evaluation to be made regarding the continued acceptability of multiple extraction activities. Research on cumulative effects represents a major departure from research on individual impacts of dredging in that it aims to evaluate the interaction of events separated in time and in space.
In an initial assessment of the scope for such cumulative effects, a review of historical data was undertaken, focusing on the dredging intensity and extent, and the performance of local fisheries. Interviews were conducted with key fishers fishing within the East of the Isle of Wight region, Central English Channel. Fishers were invited to provide an overview of their fishing activities including the location of fishing effort and discuss the extent that aggregate extraction has impinged on this activity.
It was also necessary to conduct new carefully targeted sampling regimes to cover appropriate spatial scales and especially to establish the stability of any observed effects over time. Regional scale surveys of the benthos and
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sediments were conducted in the Southern North Sea and Central English Channel. Surveys were also designed to examine the nature of impacts on the benthos arising from marine aggregate extraction. The first of these surveys was conducted in 1999 to investigate the effect of different levels of dredging intensity on macrofaunal assemblages. Samples from intensively dredged sediments differed from undredged sites due to significant reductions (p<0.05) in numbers of species, biomass, species richness and diversity. Intermediate values of all calculated univariate measures were also observed in areas of reduced dredging intensity. Populations of the polychaete Sabellaria spinulosa were found to be particularly susceptible to dredging disturbance. This is in contrast to Balanus juveniles which were observed to be more numerous in intensively dredged sediments compared with elsewhere, suggesting that some settlement of this taxon occurs even during times of extraction.
Further studies conducted in 2000 were designed to investigate the nature and footprint of biological effects arising from marine aggregate extraction. Two transects of stations located at increasing distance from active centres of dredging activity in the central English Channel were sampled for macrofauna and sediments using a 0.1 m2 Hamon grab. Both transects were aligned along the approximate direction of the prevailing tidal currents. A total of 394 macrobenthic species were recorded from 31 samples.
Univariate and graphical measures of community structure suggest that at the locations investigated the effects of marine aggregate extraction (both trailer and static dredging) are confined to within 1 km of the centre of intensive dredging. Multivariate methods appear to be more sensitive and show a clear gradient of change with increasing distance away from extraction activity extending beyond the margins of the extraction sites.
A further output of the study has been the development of generic guidelines for undertaking studies to investigate the potential for cumulative environmental effects arising as a consequence of marine aggregate extraction. The guidelines are presented in the final report together with guidance on the circumstances under which cumulative effects studies may become necessary in other areas.
7.5 Assessment of rehabilitation of the seabed following marine aggregate dredging
This four year field based study seeks to enhance the understanding of the processes leading to the physical and biological recovery of the seabed following dredging. As indicated in the previous reports, the work is being undertaken by CEFAS in collaboration with Hydraulics Research Wallingford and the British Geological Survey. The project commenced in April 2000 and is being funded by DTLR, DEFRA and The Crown Estate.
The project is now in its third year. Work completed to date includes the production of a literature review on the recolonisation of sites following the cessation of dredging and pilot field surveys at 7 sites, spanning 5 geographical areas around the English coastline. The analyses of sediment and benthic fauna at stations corresponding with different degrees of dredging intensity is continuing, but preliminary results have revealed that the fauna remains in a perturbed state within Area 222, (a small historic extraction site in the North Sea) some four years after the cessation of dredging. Therefore relatively rapid recovery rates, commonly cited as 2 to 3 years for European coastal gravelly areas, should not be assumed to be universally applicable. The results from this work have been submitted to a peer-reviewed journal. Time-series investigations are continuing at 3 locations (4 sites) in the North Sea and English Channel.
7.6 Procedural guidelines for the conduct of benthic studies at aggregate dredging sites
CEFAS have prepared, on behalf of DTLR, guidelines on the conduct of benthic surveys at commercial aggregate extraction sites to facilitate consistency of approaches amongst consultants employed by the industry when carrying out baseline and monitoring surveys. In addition, this report has been produced to foster compatibility between ongoing regulatory monitoring activity and related R&D. This document is targeted at experienced marine scientists especially benthic ecologists, sedimentologists, and geophysicists working on behalf of the aggregate extraction industry or the regulator in the conduct of R&D or, more usually, on the implementation of environmental assessment and monitoring programmes. The guidelines will inform implementation of the forthcoming policy framework for aggregate dredging in English waters to be published in Marine Minerals Guidance Note 1 (Guidance on the Extraction by Dredging of Sand, Gravel and Other Minerals from the English Seabed). A summary of the topics being covered was provided in the 2000 report.
The project was initiated in April 2000 as is expected to run for 2 years. The guidelines will be published in April/May 2002.
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7.7 A Development Plan for Marine Aggregate Dredging - A scoping study
Posford Haskoning together with CEFAS, H R Wallingford and David Tyldesley Associates were commissioned by DTLR in October 2001 to assess whether a development plan approach (i.e., spatial planning), could provide a suitable and sustainable framework for identifying and allocating future areas of the English seabed for marine aggregate dredging.
The research includes a review of:
• markets for marine aggregates; • key environmental, social and economic issues; • the extent to which approaches used in the preparation of existing plans, such as Mineral Local Plans, Shoreline Management Plans, etc., are potentially transferable to the marine setting; • the current regulatory framework for marine aggregate dredging; • other approaches to development control.
An assessment of the level of detail of data required for a development plan or alternative approach will be conducted. The current availability and the resources required to fill identified key gaps will be evaluated. Also an assessment of the feasibility/cost/timescale of producing a marine development plan or alternative will be considered.
Recommendations will be made in the final report due in December.
7.8 North Nab Research – Biological and Physical Impact of Marine Aggregate Extraction
The American Minerals Management Service has commissioned research into the biological and physical impact of marine aggregate extraction, examining the North Nab production licence located off the east of the Isle of Wight, England. The contractors, Coastline Surveys Limited and Marine Ecological Surveys Ltd, have undertaken benthic sampling in conjunction with the collection of physical information (side-scan sonar and ADCP), to assess the scale and extent of the biological impact of spatially restricted, intensive static marine aggregate dredging.
A summary of the biological results is available to be downloaded from the websites below, and the final report is in preparation.
Websites: www.mms.gov/intermar www.coastlinesurveys.co.uk www.marineecologicalsurveys.co.uk
7.9 Area 408 – Biological Impact of Marine Aggregate Extraction
BMAPA has contracted Marine Ecological Surveys Ltd to undertake research examining the direct and indirect biological impacts of marine aggregate extraction at an isolated production licence in the Southern North Sea, Area 408 (Coal Pit). The isolated location of the study area avoids many of the difficulties arising from potential cumulative and in-combination issues associated with nearshore licences.
The site was first licensed in 1995, and importantly, extraction has been by means of trailer dredgers often employing on-board screening – characteristic of the majority of marine aggregate extraction from UK waters in the Southern North Sea. A comprehensive history of extraction rates and screening returns is available from the licensee, Hanson Aggregates Marine. Over 160 Hamon grab samples were collected during the summer of 2000, in conjunction with some routine monitoring work. In addition, bathymetric and side-scan sonar data are being used to inform a seabed sediment report, detailing the composition of the seabed sediments present within the study area, and the physical processes that take place. This will be used to assist with the interpretation of the biological data.
The final report is in preparation, and should be issued during Spring 2002.
Website: www.bmapa.org
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7.10 Project A1033 – Role of seabed mapping techniques in environmental monitoring and management
This 4-year study being carried out by CEFAS started in April 2002 and is a follow-up to the A0908 project completed in March 2001. The study is considering the utility of seabed habitat mapping for the monitoring and management of several human activities that disturb the seabed e.g., disposal of dredged material, maintenance dredging, construction activities and aggregate extraction. These are relatively small-scale, localised activities but the project will also address larger-scale applications such as mapping essential fish habitat and broad-scale habitat mapping. The study will expand upon the methodologies developed in the A0908 project by evaluating additional physical and geophysical techniques, e.g., swath bathymetry and sub-bottom profiling.
7.11 Ecological Quality Objectives for Marine Aggregate Extraction Areas
A workshop to discuss the feasibility and practicality of developing Ecological Quality Objectives (EcoQOs) and associated qualitative targets designed to protect the marine environment in the vicinity of marine aggregate extraction areas was held on 11th and 12th October 2001 at CEFAS Lowestoft. The background to the workshop was the OSPAR Strategy for the Protection and Conservation of the Ecosystems and Biological Diversity of the Maritime Area and the development of EcoQOs to assist with the implementation of that approach.
The workshop agreed that the principal environmental concerns with the activity of marine aggregate extraction arise from physical impacts at the seabed and the consequential biological responses. Chemical contamination is unlikely to be an issue in most cases due to the very low organic and clay content of commercial aggregate deposits and to the fact that most of these geological deposits would not have been exposed at the surface of the seabed prior to dredging.
The workshop recommended four overarching EcoQOs for the management of marine aggregate extraction and envisaged that metrics developed for biological and physical impacts would contribute to their assessment:
• EcoQO 1: To have a proportion (x %) of each habitat that is protected from human activities. • EcoQO 2: To ensure that the proportion of habitat and associated communities impacted does not prevent the proper functioning of that system during extraction and allows recovery once dredging ceases. • EcoQO 3: Incorporate best practice in dredging operations in order to promote the recovery of impacted ecosystems. • EcoQO 4: There should be no impact outside an agreed area of influence; this is the area of primary and secondary impacts. This will be defined and assessed as part of the Environmental Impact Assessment.
EcoQOs which are in the future developed for a variety of human activities may overlap in their areas of application, for example in the case of a coastal locality which is subject to multiple uses. In such circumstances, the potential for conflicting and inconsistent EcoQOs must, at an early stage, be addressed by appropriate coordination of groups responsible for their development.
Lists of physical and biological metrics appropriate for use in assessing potential environmental impacts of marine aggregate extraction were developed and agreed by the workshop. A number of these metrics would be applicable to other human activities impacting the seabed.
Copies of the workshop report can be downloaded in PDF format from the CEFAS website at: www.cefas.co.uk/
8 United States of America
8.1 Sediment Plume Modelling
The United States Mineral Management Service has commissioned a research programme to produce a predictive desktop modelling package that links the various phases of plumes that arise from sand and aggregate dredging. It is understood that the final product will be used in a predictive manner, to assist assessment of new dredging proposals, and also to inform/guide the specifications for baseline data collection and monitoring programmes.
Website: www.mms.gov/intermar/
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9 European Union Projects
9.1 SANDPIT
SANDPIT is an EU-funded project started in 2002 to investigate the (physical) implications in time and space of large- scale extraction of marine sand. A first start is made to determine the information needed and knowledge to be developed in order to understand the effects of large and deep dredging pits.
Products of the project will be:
1) a handbook with synthesis of scientific results and practical guidelines for sandpits. 2) publications on scientific descriptions of phenomena concerning sand transport in coastal areas and sand extraction. 3) a user-friendly database on sand transport and extraction of sand. 4) validated mathematical models for the forecast of sand transport and morphological behaviour of sand pits.
Principle partners:
• WL\Delft Hydraulics (The Netherlands) • National Institute for Coastal and Marine Management (RIKZ) (The Netherlands) • HR Wallingford (UK) • University of Wales (Bangor, UK) • DHI-Institute of Water and Environment (Denmark) • Sogreah (France)
Contact person. Jan Mulder ([email protected])
9.2 EUMARSAND
European sand and gravel resources: evaluation and environmental impact of extraction (EU FP5 2002–2005).
EUMARSAND is an European research trainee network to develop integrated strategies for the prospecting and extraction of marine aggregates, including the environmental effects.
The objectives are:
1) compilation of information about use, production, availability and legal aspects at a European level; 2) evaluation of geophysical/geological techniques and instruments; 3) evaluation of existing methods concerning physical and ecological impact of extractions.
In this framework young European researches will be trained.
Partners are:
1. Fundacion AZTI. Oceanography and Marine Environment. Spain (Coordinator Adolfo Uriarte, [email protected]) 2. University of Southampton, School of Ocean and Earth Science. UK (Michael Collins, [email protected]) 3. Universiteit Gent, RCMG (Renard Centre of Marine Geology) ([email protected]) 4. National and Kapodistrian University of Athens. Faculty of Geology, Department of Geography-Climatology. Greece (Adonis Velegrakis, [email protected]) 5. University of the Aegean. Department of Marine Sciences. Greece ([email protected]) 6. Maritime Institute in Gdansk. Department of Operational Oceanography. Poland ([email protected], [email protected])
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7. Universite du Littoral Cote d'Opale. Geomorphologie Dynamique et Amenagement des Littoraux. France ([email protected]) 8. University of Twente. Department of Civil Engineering. The Netherlands ([email protected]) 9. Christian-Albrechts-Universitaet zu Kiel. Institute of Geosciences. Germany ([email protected])
9.3 SUMARE
The SUMARE project, which reported to the Working Group last year, is progressing well and further studies on the Kwintebanke and surrounding a maerl bed in Orkney will be reported next year.
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ANNEX 7: DRAFT ICES GUIDELINES FOR THE MANAGEMENT OF MARINE SEDIMENT EXTRACTION1
Introduction
In many countries, sand and gravel2 dredged from the seabed makes an important contribution to the national demand for aggregates, directly replacing materials extracted from land-based sources. This reduces the pressure to work land of agricultural importance or environmental and hydrological value, and where materials can be landed close to the point of use, there can be additional benefits of avoiding long distance over-land transport. Marine dredged sand and gravel is also increasingly used in flood and coastal defence, and land reclamation schemes. For beach replenishment, marine materials are usually preferred from an amenity point of view, and are generally considered to be the most appropriate economically, technically, and environmentally.
However, these benefits need to be balanced against the potential negative impacts of aggregate dredging. Aggregate dredging activity, if not carefully controlled, can cause significant damage to the seabed and its associated biota, to commercial fisheries and to the adjacent coastlines, as well as creating conflict with other users of the sea. In addition, current knowledge of the resource indicates that while there are extensive supplies of some types of marine sand, there appear to be more limited resources of gravel suitable, for example, to meet current concrete specifications and for beach nourishment.
Against the background of utilising a finite resource, with the associated environmental impacts, it is recommended that regulators develop and work within a strategic framework which provides a system for examining and reconciling the conflicting claims on land and at sea. Decisions on individual applications can then be made within the context of the strategic framework.
General principles for the sustainable management of all mineral resources overall include:
• conserving minerals as far as possible, whilst ensuring that there are adequate supplies to meet the demands of society; • encouraging their efficient use (and where appropriate re-use), minimising wastage, and avoiding the use of higher quality materials where lower grade materials would suffice; • ensuring that methods of extraction minimise the adverse effects on the environment, and preserve the overall quality of the environment once extraction has ceased; • protecting sensitive areas and industries, including fisheries, important habitats (such as marine conservation areas), and the interests of other legitimate users of the sea; and • preventing unnecessary sterilisation of mineral resources by other forms of development.
The implementation of these principles requires a knowledge of the resource, an understanding of the potential impacts of its extraction and of the extent to which rehabilitation of the seabed is likely to take place. The production of an Environmental Statement, developed along the lines suggested below, should provide a basis for determining the potential effects and identifying possible mitigating measures. There will be cases where the environment is too sensitive to disturbance to justify the extraction of aggregate, and unless the environmental and coastal issues can be satisfactorily resolved, extraction should not normally be allowed.
It should also be recognised that improvements in technology may enable exploitation of marine resources from areas of the seabed which are not currently considered as reserves, while development of technical specifications for concrete, etc., may in the future enable lower quality materials to be used for a wider range of applications. In the shorter term, continuation of programmes of resource mapping may also identify additional sources of coarser aggregates.
1 These guidelines do not relate to navigational dredging (i.e., maintenance or capital dredging). 2 It is recognized that other materials are also extracted from the seabed, such as stone shell and maerl, and similar considerations should apply to them.
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Scope
It is recognised that sand and gravel extraction, if undertaken in an inappropriate way, may cause significant harm to the marine and coastal environment. There are a number of international and regional initiatives that should be taken into account when developing national frameworks and guidelines. These include the Convention on Biological Diversity (CBD), EU Directives (particularly those on birds, EIA and habitats) and other regional conventions/agreements, in particular, the OSPAR and Helsinki Conventions, and initiatives pursued under them. This subject for example has recently been included in the Action Plan for Annex V to the 1992 OSPAR Convention on the “Protection and Conservation of the Ecosystems and Biological Diversity of the Maritime Area” as a human activity requiring assessment.
Administrative framework
It is recommended that countries have an appropriate framework for the management of sand and gravel extraction and that they define and implement their own administrative framework with due regard to these guidelines. There should be a designated authority to:
• issue permits, having fully considered the potential environmental effects; • be responsible for compliance monitoring; • the framework for monitoring; • enforcing conditions.
Environmental impact assessment
The extraction of sand and gravel from the seabed can have significant physical and biological effects on the marine and coastal environment. The significance and extent of the environmental effects will depend upon a range of factors including the location of the licensed area, the nature of the surface and underlying sediment, coastal processes, the design, method, rate, amount and intensity of extraction, and the sensitivity of habitats, fisheries and other uses in the locality. These factors are considered in more detail below. Particular consideration should be given to sites designated under international, European, national and local legislation, in order to avoid unacceptable disturbance or deterioration of these areas for the habitats, species and other designated features.
To enable the organisation(s) responsible for licensing extraction to evaluate the nature and scale of the effects and to decide whether a proposal can proceed, it is necessary that an adequate assessment of the environmental effects be carried out. It is important, for example, to determine whether the application is likely to have an effect on the coastline, or have potential impact on fisheries and the marine environment.
The Baltic Marine Environment Protection Commission (Helsinki Commission) adopted HELCOM Recommendation 19/1 on 26 March 1998. This recommends to the Governments of Contracting Parties that an environmental impact assessment (EIA) should be undertaken in all cases before an extraction permit is issued. For EU Member States, the extraction of minerals from the seabed falls within Annex II of the “Directive on the Assessment of the Effects of Certain Public and Private Projects on the Environment” (85/337/EEC)3. As an Annex II activity, an EIA is required if the Member State takes the view that one is necessary. It is at the discretion of the individual Member States to define the criteria and/or threshold values that need to be met to require an EIA. The Directive was amended in March 1997 by Directive 97/11/EC. Member States are obliged to transpose the requirements of the Directive into national legislation by March 1999.
It is recommended that the approach adopted within the EU be followed. Member States should therefore set their own thresholds for deciding whether and when an EIA is required.
Where an EIA is considered appropriate, the level of detail required to identify the potential impacts on the environment should be carefully considered and identified on a site-specific basis. An EIA should normally be prepared for each extraction area, but in cases where multiple operations in the same area are proposed, a single impact assessment for the whole area may be more appropriate, which takes account of the potential for any cumulative impacts. In such cases, consideration should be given to the need for a strategic environmental assessment.
3 EIA Directive
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Consultation is central to the EIA process. The framework for the content of the EIA should be established by early consultation with the licensing authority, statutory consultees, and other interested parties. Where there are potential transboundary issues, it will be important to undertake consultation with the other countries likely to be affected, and the relevant Competent Authorities are encouraged to establish procedures for effective communication.
As a general guide, it is likely that the following topics considered below will need to be addressed.
Description of the physical setting
The proposed extraction area should be identified by geographical location, and described in terms of:
• the bathymetry and topography of the general area; • the distance from the nearest coastlines; • the geological history of the deposit; • the source of the material; • type of material; • sediment particle size distribution; • extent and volume of the deposit; • the stability and/or natural mobility of the deposit; • thickness of the deposit and evenness over the proposed extraction area; • the nature of the underlying deposit, and any overburden; • local hydrography including tidal and residual water movements; • wind and wave characteristics; • average number of storm days per year; • estimate of bed-load sediment transport (quantity, grain size, direction); • topography of the seabed, including occurrence of bedforms; • existence of contaminated sediment and their chemical characteristics; • natural (background) suspended sediment load under both tidal currents and wave action.
Description of the biological setting
The biological setting of the proposed extraction site and adjacent areas should be described in terms of:
• the flora and fauna within the area likely to be affected by aggregate dredging (e.g., pelagic and benthic community structure), taking into account temporal and spatial variability; • information on the fishery and shellfishery resources including spawning areas with particular regard to benthic spawning fish, nursery areas, over-wintering grounds for ovigerous crustaceans, and known routes of migration; • trophic relationships (e.g., between the benthos and demersal fish populations by stomach content investigations); • presence of any areas of special scientific or biological interest in or adjacent to the proposed extraction area, such as sites designated under local, national, or international regulations (e.g., Ramsar sites, the UNEP “Man and the Biosphere” Reserves, World Heritage sites, Marine Protection Areas (MPAs) Marine Nature Reserves, Special Protection Areas (Birds Directive), or the Special Areas of Conservation (Habitats Directive).
Description of the proposed aggregate dredging activity
The assessment should include, where appropriate, information on:
• the total volume to be extracted; • proposed maximum annual extraction rates and dredging intensity; • expected lifetime of the resource and proposed duration of aggregate dredging; • aggregate dredging equipment to be used; • spatial design and configuration of aggregate dredging (i.e., the maximum depth of deposit removal, the shape and area of resulting depression);
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• substrate composition on cessation of aggregate dredging; • proposals to phase (zone) operations; • whether on-board screening (i.e., rejection of fine or coarse fractions) will be carried out; • number of dredgers operating at a time; • routes to be taken by aggregate dredgers to and from the proposed extraction area; • time required for aggregate dredgers to complete loading; • number of days per year on which aggregate dredging will occur; • whether aggregate dredging will be restricted to particular times of the year or parts of the tidal cycle; • direction of aggregate dredging (e.g., with or across tide).
It may be appropriate, when known, also to include details of the following:
• energy consumption and gaseous emissions; • ports for landing materials; • servicing ports; • on-shore processing and onward movement; • project-related employment.
Information required for physical impact assessment
To assess the physical impacts, the following should be considered:
• implications of extraction for coastal and offshore processes, including possible effects on beach draw down, changes to sediment supply and transport pathways, changes to wave and tidal climate; • changes to the seabed topography and sediment type; • exposure of different substrates; • changes to the behaviour of bedforms within the extraction and adjacent areas; • potential risk of release of contaminants by aggregate dredging, and exposure of potentially toxic natural substances; • transport and settlement of fine sediment disturbed by the aggregate dredging equipment on the seabed, and from hopper overflow or on-board processing and its impact on normal and maximum suspended load; • the effects on water quality mainly through increases in the amount of fine material in suspension; • implications for local water circulation resulting from removal or creation of topographic features on the seabed; • time scale for potential physical “recovery” of the seabed.
Information required for biological impact assessment
To assess the biological impact, the following information should be considered:
• changes to the benthic community structure; • effects of aggregate dredging on pelagic biota; • effects on the fishery and shellfishery resources including spawning areas with particular regard to benthic spawning fish, nursery areas, overwintering grounds for ovigerous crustaceans, and known routes of migration; • effects on trophic relationships (e.g., between the benthos and demersal fish populations); • effects on sites designated under local, national, or international regulations (see above); • predicted rate and mode of recolonisation, taking into account initial community structure, natural temporal changes, local hydrodynamics, and any predicted change of sediment type; • effects on marine flora and fauna including seabirds and mammals; • effects on the ecology of boulder fields/stone reefs.
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Interference with other legitimate uses of the sea
The assessment should consider the following in relation to the proposed programme of extraction:
• commercial fisheries; • shipping and navigation lanes; • military exclusion zones; • offshore oil and gas activities; • engineering uses of the seabed (e.g., adjacent extraction activities, undersea cables and pipelines including associated safety and exclusion zones); • areas designated for the disposal of dredged or other materials; • location in relation to existing or proposed licensed aggregate extraction areas; • location of wrecks and war-graves in the area and general vicinity; • wind farms; • areas of heritage, nature conservation, archaeological and geological importance; • recreational uses; • general planning policies for the area (international, national, and local); • any other legitimate use of the sea.
Evaluation of impacts
When evaluating the overall impact, it is necessary to identify and quantify the marine and coastal environmental consequences of the proposal. The EIA should evaluate the extent to which the proposed extraction operation is likely to affect other interests of acknowledged importance. Consideration should also be given to the assessment of the potential for cumulative impacts on the marine environment. In this context, cumulative impacts might occur as a result of aggregate dredging at a single site over time, from multiple sites in close proximity or in combination with effects from other human activities (e.g., fishing and disposal of harbour dredging).
It is recommended that a risk assessment be undertaken. This should include consideration of worst case scenarios, and indicate uncertainties and assumptions used in their evaluation.
The environmental consequences should be summarised as an impact hypothesis. The assessment of some of the potential impacts requires predictive techniques, and it will be necessary to use appropriate mathematical models. Where such models are used, there should be sufficient explanation of the nature of the model, including its data requirements, its limitations and any assumptions made in the calculations, to enable assessment of its suitability for the particular modelling exercise.
Mitigation Measures
The impact hypothesis should include consideration of the steps that might be taken to mitigate the effects of extraction activities. These may include:
• the selection of aggregate dredging equipment and timing of aggregate dredging operations to limit impact upon the biota (such as birds, benthic communities, and fish resources); • modification of the depth and design of aggregate dredging operations to limit changes to hydrodynamics and sediment transport and to minimise the effects on fishing; • spatial and temporal zoning of the area to be licensed or scheduling extraction to protect sensitive fisheries or to respect access to traditional fisheries; • preventing on-board screening or minimising material passing through spillways when outside the dredging area to reduce the spread of the sediment plume; • agreeing exclusion areas to provide refuges for important habitats or species, or other sensitive areas.
Evaluation of the potential impacts of the aggregate dredging proposal, taking into account any mitigating measures, should enable a decision to be taken on whether or not the application should proceed. In some cases, it will be
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appropriate to monitor certain effects as the aggregate dredging proceeds. The EIA should form the basis for the monitoring plan.
Permit Issue
When an aggregate extraction operation is approved, then a permit authorising it should be issued in advance. In granting a permit, the immediate impact of aggregate extraction occurring within the boundaries of the extraction site, such as alterations to the local physical and biological environment, is accepted by the permitting authority. Notwithstanding these consequences, the conditions under which a permit for aggregate extraction is issued should be such that environmental changes beyond the boundaries of the extraction site are as far below the limits of allowable environmental change as practicable. The operation should be permitted subject to conditions which further ensure that environmental disturbance and detriment are minimised.
The permit is an important tool for managing aggregate extraction and will contain the terms and conditions under which aggregate extraction may take place as well as provide a framework for assessing and ensuring compliance.
Permit conditions should be drafted in plain and unambiguous language and will be designed to ensure that: a) the material is only extracted from within the selected extraction site; b) any mitigation requirements are complied with; and c) any monitoring requirements are fulfilled and the results reported to the permitting authority.
Monitoring compliance with licence conditions
An essential requirement for the effective control of marine aggregate extraction is monitoring on a continuous basis of all aggregate dredging activity to provide a permanent record. This has been achieved in several ways, e.g., an Electronic Monitoring System or Black Box. The information provided will allow the regulatory authority to monitor the activities of aggregate dredging vessels to ensure compliance with particular conditions in the permission.
The information collected and stored will depend on the requirements of the individual authorities and the regulatory regime under which the permission is granted, e.g., EIA, Habitats, Birds Directives of the EU.
The minimum requirements for the monitoring system should include:
• an automatic record of the date, time, and position of all aggregate dredging activity; • position to be recorded to within a minimum of 100 metres in latitude and longitude or other agreed coordinates using a satellite-based navigation system; • there should be an appropriate level of security; • the frequency of recording of position should be appropriate to the status of the vessel, i.e., less frequent records when the vessel is in harbour or in transit to the aggregate dredging area, e.g., every 30 minutes, and more frequently when dredging, e.g., every 30 seconds.
The above are considered to be reasonable minimum requirements to enable the regulatory authority to monitor the operation of the licence in accordance with any conditions attached to the licence. Individual countries may require additional information for compliance monitoring at their own discretion.
The records can also be used by the aggregate dredging company to improve utilisation of the resources. The information is also an essential input into the design and development of appropriate environmental monitoring programmes and research into the physical and biological effects of aggregate dredging including combined or cumulative impacts (see section above).
Environmental Monitoring
Sand and gravel extraction inevitably disturbs the marine environment. The extent of the disturbance and its environmental significance will depend on a number of factors. In many cases, it will not be possible to predict, in full, the environmental effects at the outset, and a programme of monitoring may be needed to demonstrate the validity of the EIA’s predictions, the effectiveness of any conditions imposed on the permit, and therefore the absence of unacceptable impacts on the marine environment.
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The level of monitoring should depend on the relative importance and sensitivity of the surrounding area. Monitoring requirements should be site-specific, and should be based, wherever possible, on the findings of the EIA. To be cost effective, monitoring programmes should have clearly defined objectives derived from the impact hypothesis developed during the EIA process. The results should be reviewed at regular intervals against the stated objectives, and the monitoring exercise should then be continued, revised, or even terminated.
It is also important that the baseline and subsequent monitoring surveys take account of natural variability. This can be achieved by comparing the physical and biological status of the areas of interest with suitable reference sites located away from the influence of the aggregate dredging effects, and of other anthropogenic disturbance. Suitable locations should be identified as part of the EIA's impact hypothesis.
(A monitoring programme may include assessment of a number of effects.) When developing the programme, a number of questions should be addressed, including:
• what are the environmental concerns that the monitoring programme seeks to address; • what measurements are necessary to identify the significance of a particular effect; • what are the most appropriate locations at which to take samples or observations for assessment; • how many measurements are required to produce a statistically sound programme; • what is the appropriate frequency and duration of monitoring.
The permitting authority is encouraged to take account of relevant research information in the design and modification of monitoring programmes.
The spatial extent of sampling should take account of the area designated for extraction and areas outside which may be affected. In some cases, it may be appropriate to monitor more distant locations where there is some question about a predicted nil effect. The frequency and duration of monitoring may depend upon the scale of the extraction activities and the anticipated period of consequential environmental changes which may extend beyond the cessation of extraction activities.
Information gained from field monitoring (or related research studies) should be used to amend or revoke the permit, or refine the basis on which the aggregate extraction operation is assessed and managed. As information on the effects of marine aggregate dredging becomes more available and a better understanding of impacts is gained, it may be possible to revise the monitoring necessary. It is therefore in the interest of all concerned that monitoring data are made widely available. Reports should detail the measurements made, results obtained, their interpretation, and how these data relate to the monitoring objectives.
Reporting Framework
It is recommended that the national statistics on aggregate dredging activity continue to be collated annually by ICES WGEXT.
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ANNEX 8: COOPERATION BETWEEN ICES (WGEXT) AND OSPAR (BDC SUBGROUP SEABED)
ICES WGEXT MINISTRY OF Annual meeting 2002 ENVIRONMENT DANISH FOREST AND NATURE AGENCY J.no. SN 2001–8841/49–0001
Cooperation between ICES (WGEXT) and OSPAR (BDC subgroup SEABED) 25 March 2002
ICES (WGEXT) meeting April 2002, Boulogne-Sur-Mer Presented by Denmark: At OSPAR(BDC/SEABED) meeting 2001 SEABED recalled that BDC 2000 had agreed that Denmark, as lead country in OSPAR for work on sand and gravel, should prepare, for discussion at SEABED 2001 and subsequently at BDC 2001: a) an overview assessment of environmental effects of sand and gravel extraction; b) proposals for reporting data and information on sand and gravel activities; c) draft OSPAR Guidelines on sand and gravel extraction.
Concerning:
Item a. Denmark informed SEABED at the meeting 2001 that work similar to the proposed overview assessment of the environmental effects of sand and gravel extraction had been undertaken within ICES in recent years, and that this work result in a revision of the ICES Cooperative Research Report No. 182 Effects of extraction of marine sediments on fisheries, appendix A.
The revised CRR No. 247 “Effects of extraction of marine sediments on the marine ecosystem” was published in December 2001, and distributed by Denmark to SEABED Heads of Delegation with a request for Contracting Parties to comment, by 31 March 2002, on:
(i). Whether the revised CRR covered all of the issues that should be addressed by an OSPAR overview assessment of the environmental effects of sand and gravel extraction; (ii). Any aspects not covered, or not covered in sufficient detail, by the revised CRR; (iii). Whether there was a need for Denmark to undertake any further work on an overview assessment of the environmental effects of sand and gravel extraction for OSPAR. b. Denmark should report the outcome of (i-iii) at the next meeting of SEABED,
including proposals on how to address any additional assessment needs identified by Contracting Parties. Although this request is not addressed to ICES, Denmark would appreciate a short discussion: a) in general; b) in relation to received comments, see below.
Comments Received from Contracting Parties:
United Kingdom. Appendix B
UK conclude that the present CRR does provide an adequate basis for the next
meeting of SEABED to decide on whether OSPAR should develop guidelines or other measures in relation to marine sand and gravel extraction. Miljøministeriet Skov- og Naturstyrelsen The SEABED meeting should also consider whether any further work needs to be undertaken Haraldsgade 53 in future on developing the overview assessment in the light of new research findings etc. In DK-2100 København Ø our opinion it would be appropriate for the ICES working group to continue to take the lead Phone: +45 39 47 20 00 in carrying out any such work, in view of the broad range of biological, geological and Fax: +45 39 27 98 99 technical expertise available to it. E-mail: [email protected]
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Item b. Denmark presented a draft proposal of a schedule for reporting data and information on sand and gravel extraction activities. Appendix C.
A number of delegations indicated that they had comments on the reporting schedule proposed by Denmark.
SEABED agreed: a) that Contracting Parties should provide their comments on the draft reporting schedule to Denmark by 31 December 2001. b) to invite Denmark to:
i. revise the draft reporting schedule on the basis of the comments made by Contracting Parties; ii. determine whether the data on the use of marine aggregates that is currently reported to ICES would be sufficient to complete the revised draft reporting schedule, and whether ICES would be in a position to forward these data annually to OSPAR; iii. present to SEABED 2002 a revised reporting schedule along with proposals and justification for future reporting and assessment of data and information on the application of marine aggregates.
As already mentioned, the Danish proposal is found in appendix C.
Below, Denmark present the comments received until now coming from France (F), Germany (D) and United Kingdom (UK).
Copy of the proposed schedule followed by comments from Contracting Parties.
OSPAR Reporting data and information on sand and gravel extraction activities Country Year Application Extraction Dredging equipment Amount Total 103 m³/t 103 m³/t Area Type Depth SSD TSD Aggregates for construction Sand fill for reclamation Beach Nourishment Beneficial use of dredged material
France. Appendix D
Area should be stated more exactly by a surface unit of measurement and added the column Code of the extraction site; End use of material is not a part of the permission and will be difficult to report; Beach nourishment is one of the more beneficial uses of dredged material; Beneficial uses of dredged material are more related to compulsory dredging for navigational purposes than deliberate extraction for economical purposes.
Germany. Appendix E
Removal of dredged material is not regarded as “sand and gravel extraction” Dredging and extraction are administered in two different legal frameworks Delete Beneficial use of dredged material.
80 2002 WGEXT Report
United Kingdom. Appendix F
Application changed to End use of material; Beneficial use of dredged material changed to Other uses; Area changed to Area/region because no information on individual licensed areas, only on a regional basis; Type and corresponding footnote deleted because no detailed information; Depth deleted because of no use; only quantity is important; Dredging equipment deleted because no detailed information; What is the difference between amount and total?
Some comments from Denmark:
1) Exploration and extraction of raw materials in territorial waters and on the continental shelf may take place only in geographically demarcated areas, which have been subject to an environmental assessment and subject to a permit from the Minister for Environment. The permission does include information about dredging equipment. 2) The holder of a permission report quarterly to the Danish authority about the identity of the vessel, the extraction area, and for each cargo the position for the extraction activity, the depth, the type of raw material and the amount of material together with the area of unloading. 3) Beneficial use of dredged material does not include extraction, but dredged material may be used as raw material and thereby not dumped. This is a way of prolonging the resources of raw material and are, therefore, duty free.
Draft list of issues to be discussed in WGEXT:
1. What is the purpose or use of the reported data and information? a) Are data going to reflecting information needed in an EIA? b) Are data restricted to extraction an amount and extracted material? 2. Are data currently reported to ICES sufficient already? 3. Is ICES in a position to forward this data annually to OSPAR?
Item c. Denmark presented the draft Guidelines on sand and gravel extraction, which had been prepared by a WGEXT-subgroup in December 2000 and further developed at the ICES/WGEXT meeting in April 2001. Appendix G.
Denmark proposed that these ICES Guidelines might form the basis for a strategic framework, for how to control sand and gravel extraction in OSPAR.
SEABED agreed that:
a) Contracting Parties should provide detailed comments on the draft guidelines to Denmark by 31. December 2001. b) Denmark should inform ICES/WGEXT at the meeting in April 2002 about the comments made by contracting parties and invite ICES/WGEXT to take the comments into account in the further development of the draft guidelines on sand and gravel extraction.
Denmark has, until now, received comments from France (F), Germany (D) and United Kingdom (UK).
France, appendix D:
France wants to stress the importance of balancing between the volume of extracted material over time and the requirement for the EIA.
2002 WGEXT Report 81
Germany, appendix E:
Germany recommends that dredging and dredging activities are replaced by extraction or extraction activities in the whole draft; § 16 c: Germany does not understand the purpose and necessity for the predator/prey relationship; § 18: The introductory sentence (While not directly...) should be simplified. Our proposal is to replace this sentence by: Furthermore, the EIA may include:...... § 21: As there may be some more legitimate uses we propose to add: a “e.g.” after...proposed programme of extraction.
United Kingdom, appendix F:
No further comments on the guidelines at this stage.
Denmark:
At the SEABED meeting in 2001 delegates questioned the need for such guidelines in OSPAR.
Although this question is not addressed directly to ICES/WGEXT Denmark would appreciate a discussion of the need of guidelines before the more detailed discussion about further develop of the guidelines.
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ICES/WGEXT 2002 ANNEX 8 SEABED 01/3/1-E (L) Appendix A Original: English English only
OSPAR CONVENTION FOR THE PROTECTION OF THE MARINE ENVIRONMENT OF THE NORTH-EAST ATLANTIC MEETING OF THE WORKING GROUP ON THE USE OF AND IMPACT ON THE SEABED (SEABED) LONDON (SECRETARIAT): 2–4 OCTOBER 2001
Overview assessment of environmental effects of sand and gravel extraction
Presented by Denmark
Background
1. At IMPACT, 1998 Denmark presented the paper “Impact of Marine Sand and Gravel extraction”. The paper was a review of the impact of exploitation of marine sand and gravel resources as a background document for furthering the work on JAMP issue 6.4. A very important reference in the review was the ICES Cooperative Research Report no. 182 “Effects of extraction of marine sediments on fisheries” and 19 other references with attach importance to the Danish experience from the Great Belt link and the Initiator Øresund link. Denmark stressed the importance of the work done in the ICES Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem, WGEXT and Denmark informed IMPACT that the ICES Cooperative Research Report was under revision. The revision has unfortunately been delayed but will be published in November 2001 according to ICES Head Office in Copenhagen, September 2001. Denmark has recently received a final draft version of the report and passes on with permission from ICES Head Office the summary of impacts and ecological response:
2. A model of macrobenthic community response to the effects of dredging is now emerging. The response may be divide into three phases, namely;
Phase I, an initial recolonisation by dominant taxa present before dredging. These animals are predominantly opportunistic in behaviour and they significantly contribute to an increase in the overall abundance and total numbers of species during the first few months following the cessation of dredging,
Phase II, is characterised by a low community biomass which may persist for several years. This may be caused by increased amounts of sediment (mainly sand) in transport, which is also responsible for the erosion of dredged tracks, infilling of dredged pits, and the scouring of the epibenthos. In time the sand transport reaches the pre-dredged Equilibrium State, which results in Phase III of the recovery, which is characterised by a significant increase in the community biomass.
3. Clearly, the same biological and physical response to dredging cannot be assumed to occur elsewhere, i.e., the findings are site specific. Nevertheless, it may be concluded that dredging of commercial sand and gravel deposits in areas of relatively high natural disturbance, e.g., off the east coast of England, off Dieppe and in the North Sea borrow sites may be of little long-time (i.e., three years) biological significance due to the potential speed of physical and biological recovery following dredging. This conclusion clearly has wider implications for environmental assessment of aggregate dredging, and therefore requires further validation by quantitative field sampling at these and other locations.
4. In order to supplement the conclusion of the ICES Cooperative Research Report a few comments are presented from the conclusion of the Danish paper (SEBA 99/14/1).
5. An important condition for the establishment of a biological community comparable to the pre-dredged state is that the seabed exhibits the same physical characteristics as before dredging. Recovery after physical disturbance of the seabed depends mainly on shear-stress and sediment composition, both of which are very local factors which makes it difficult to generalise physical recovery in time.
2002 WGEXT Report 83
6. Sediment transport along the sea bottom is mainly started by wave action lifting or loosening the sediment while the actual transport of the now movable sediment is depending on the current energy, the so called bedfood-process. Movable sand and high exposure seems to be a reality only in tidal channels, where recovery after dredging is achieved within 2 years. In tidal watersheds the recovery period is 4 to 10 years and in tidal flat areas the recovery period is more than 15 years. Disturbance and destabilisation of the seabed sediment followed by mobilising and transport caused by local hydrological conditions is considered to be responsible for the maintenance of a benthic community at an early developmental stage dominated by newly settled organisms with low individual biomass.
7. While physical recovery may be achieved immediately or within a few years the biological recovery seems to be more complex and may take years depending not only on the recolonisation and growth of the dominant species but also on the interactions between these and other species of higher trophic levels. In a standard specification rapidly recolonisation by natural processes are only the results when measured in terms of densities and number of species. Long-term recovery depends on biomass of long living species and the role of the bottom fauna as a food resources for higher trophic levels (seabirds and demersal fishes).
Action Requested
8. In the light of the agreement at ASMO 2000 on how Denmark as lead country should pursue the development of OSPAR work with respect to the sector “exploitation of sand and gravel” (ASMO 2000 Summary Record – ASMO 00/18/1 §§ 9.10–9.13), SEABED is invited to: a) accept the revised ICES Cooperative Research Report as the overview assessment of environmental effects of sand and gravel extraction and agree that Denmark should discuss distribution of the report to SEABED/BDC Heads of Delegation with ICES Head Office as soon as the report is published; or b) agree that Denmark should produce a shorter review mainly of the Cooperative Research Report and circulate it to Heads of Delegations for comment.
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WGEXT ANNEX 8 APPENDIX B
Mr Kjeld Jorgensen Danish Environmental Protection Agency Ministry of Environment and Energy Strandgade 29 DK-1401 Copenhagen K Denmark 19 March 2002
Dear Kjeld
OSPAR SEABED: ICES REPORT ON SAND AND GRAVEL EXTRACTION
Thank you for circulating copies of the ICES Cooperative Research Report on the effects of extraction of marine sediments on the marine ecosystem. Contracting Parties were invited to report to Denmark on whether the report covered all the issues that should be addressed by an OSPAR overview assessment of the environmental effects of sand and gravel extraction.
The UK welcomes the ICES report and believes that, while it is lacking in certain areas and will need to be updated in future, it is adequate in its present form to be accepted by OSPAR as an initial overview assessment of the effects of this activity. We have a few specific observations on the report as follows.
The drafting of the report stopped around three years ago so it is somewhat out of date. In the meantime there has been a good deal of relevant research undertaken in the UK and elsewhere (e.g., on cumulative impacts and seabed rehabilitation), much of which is ongoing. There have also been important legislative developments such as adoption of the EC Directive on Strategic Environmental Assessment. There are, however, at present few published final research reports which would provide a basis for substantial revision of the ICES document. This situation is likely to change over the next few years.
There is no reference in the report to the ecosystem approach to management of the marine environment, nor to the important issue of cumulative impacts. The section of the report dealing with the environmental effects of sand and gravel extraction is of good quality but not very extensive. We note that the ICES Working Group is likely to start work on a new report at its next meeting, although this is unlikely to be published for another three to five years.
Nevertheless, we consider that the present ICES report does provide an adequate basis for the next meeting of SEABED to decide on whether, in its view, OSPAR should develop guidelines or other measures in relation to marine sand and gravel extraction. The meeting should also consider whether any further work needs to be undertaken in future on developing the overview assessment in the light of new research findings etc. In our opinion it would be appropriate for the ICES working group to continue to take the lead in carrying out any such work, in view of the broad range of biological, geological and technical expertise available to it.
I hope that this is helpful.
Yours sincerely,
Lewis Baker
Lewis Baker
Marine and Waterways Division
2002 WGEXT Report 85
ICES (WGEXT) 2002 ANNEX 8 SEABED 01/3/2-E (L) Appendix C Original: English English only
OSPAR CONVENTION FOR THE PROTECTION OF THE MARINE ENVIRONMENT OF THE NORTH-EAST ATLANTIC MEETING OF THE WORKING GROUP ON THE USE OF AND IMPACT ON THE SEABED (SEABED) LONDON (SECRETARIAT): 2–4 OCTOBER 2001
Proposals for reporting data and information on sand and gravel extraction activities
Presented by Denmark
Background
1. An unambiguous definition of marine aggregates is hardly possible in a geological way. On the other hand there are very good comparable definitions of the variety of applications of marine aggregates. Denmark therefore recommends that data on application of marine aggregates is used as key information on sand and gravel extraction activities. To facilitate this, a draft proposal for a schedule for reporting key information on sand and gravel extraction activities has been prepared and is attached as an Annex to this document.
Action requested
2. SEABED is invited to:
a) discuss the principle of the attached schedule and to make arrangements for Heads of Delegations to send to Denmark their comments or proposals for further development of the schedule;
b) agree that Denmark should present the revised schedule to ICES (WGEXT) for further development in relation to the ongoing work on guidelines;
c) discuss the possibility of letting ICES(WGEXT) report the data schedule to OSPAR.
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Proposed reporting schedule
OSPAR REPORTING DATA AND INFORMATION ON SAND AND GRAVEL EXTRACTION ACTIVITIES Country Year Application Extraction Dredging equipment Amount Total 103 m³/t* 103 m³/t* Area Type* Depth SSD TSD Aggregates for construction
Sand fill for reclamation
Beach Nourishment
Beneficial use of dredged material
Area: The split up into individual extraction area possible informed by name/number Type: At least information of S=sand, G=gravel, RB=rocks and boulders, M=maerl or SS=shelly sand Depth: Information about dredging depth in meters the reporting year SSD: Stationary suction dredging TSD: Trailing suction dredging Amount: The asterisk indicate information of conversion factor from m3 to tons
2002 WGEXT Report 87
WGEXT ANNEX 8 Appendix D
Fra: Amparo [[email protected]] Sendt: 14. November 2001 12:13 Til: '[email protected]' Cc: Dornford; Corinne Emne: FW: SEABED 2001 - Sand and gravel extraction
Dear Mr Helmig
Following agreements at SEABED 2001, please find below the comments from the French delegation on the draft reporting schedule on sand and gravel extraction (SEABED 01/3/2-E(L).
Kind regards, Amparo Agrait Deputy Secretary
**************************************************************************** *********************
OSPAR Commission / Bonn Agreement, New Court, 48 Carey Street, London WC2A 2JQ Tel: +44 (0) 20 7430 5205 / Fax: + 44 (0) 20 7430 5225 Email: [email protected] / [email protected] http://www.ospar.org http://www.bonnagreement.org
-----Original Message-----
From: “LE QUILLEC Régis, CETMEF/compiègne” [SMTP:[email protected]]
-----Message d'origine----- De: LE QUILLEC Régis, CETMEF/compiègne Envoyé: mercredi 14 novembre 2001 11:08 À: '[email protected]'; '[email protected]' Cc: '[email protected]'; '[email protected]' Objet: SEABED 2001 - Sand and gravel extraction
Dear Colleagues,
1 - According to the summary record of the Seabed meeting 2001, contracting parties are expected to provide comments on the draft reporting schedule (Seabed 01/3/2-E(L)) proposed by Denmark by 31 December 2001. You will find below the comments of France:
1a: It should be interested to know if the extraction operation is licensed by a permit and to distinguish between the amounts licensed and amounts really extracted during the year.
1b: Before the column “Area” (precisions on the surface unit required), it should be added a column “Code of the extraction site”. 1c: In France, the permit is given on a specific area, with an annual maximum amount licensed and a specific monitoring required; but the use of the extracted gravel is quite never written in the permit. This information on the “application” might not always be easy to reach (especially from private company).
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1d: On the classification of the use of extracted material, the nourishment of beach by extracted sand is one “beneficial use of dredged material”. Moreover, the expression “Beneficial use of dredged material” seems to be more related to compulsory dredging operations for navigational purposes than deliberate extraction for economical purposes.
2 - According to the summary record of the Seabed meeting 2001, contracting parties are expected to provide comments on the draft guidelines proposed by Denmark by 31 December 2001 (Seabed 01/3/3-E (L)). France just want to stress the importance of balancing in the text, on the one hand, the volume (and consequently the price) of the studies undertaken to assess the impact of the work and, on the other hand, the extent of the annual operations of extraction.
Kind regards. LE QUILLEC Régis Centre d'Etudes Techniques Maritimes Et Fluviales (CETMEF) 2 boulevard Gambetta - BP 60039 60321 COMPIEGNE Cedex
2002 WGEXT Report 89
WGEXT ANNEX 8 Appendix E
Fra: Ralf Wasserthal [[email protected]] Sendt: 20. December 2001 14:43 Til: Helmig. Stig Cc: Dr Birgit Schubert; Klaus Soentgerath Emne: SEABED
(Bfl-A~Follow-up SEABED 2001 - Sand and gravel extraction
Dear Stig Helmig,
Please find enclosed the German comments on SEABED 01/3/2 and 01/3/3.
SEABED 01/3/2
I refer to Paragraph 3.2 and 3.3 of the Summary Record SEABED 2001 and wish to provide comments on the draft reporting schedule As already indicated at the SEABED meeting, we have problems with the proposed reporting schedule. The objective of the reporting is to get information on sand and gravel extraction activities. As we see it, the removal of dredged material cannot be regarded as “sand and gravel extraction”. In Germany, the legal framework for sand and gravel extraction is the German Mining Law which inter alia controls the extraction of raw material. Dredged material has a different legal framework and the activity serves a different purpose - namely e.g. the maintenance of navigation (not the use of the material).
Therefore, our proposal would be to simply delete the application “beneficial use of dredged material” from the reporting schedule.
SEABED 01/3/3
I refer to Paragraph 3.4 and 3.5 of the Summary Record SEABED 2001 and wish to provide comments on the draft Guidelines on sand and gravel extraction We think that the draft which is based on ICES work is in general a good one. We assume that a detailed discussion will take place at the next SEABED meeting.
In order to distinguish between the two separate issues “sand and gravel extraction” and “dredged material” we highly recommend to replace dredging or dredging activities by extraction activities in the whole draft (e.g., in Para 1 and the heading of para 17 in Annex 1 of your draft). For us it is important that extraction and dredging is not mixed up.
Paragr. 16 c: we do not really see the purpose and necessity for the predator/prey relationship Para 18: The introductory sentence (While not directly...) should be simplified. Our proposal is to replace this sentence by:
Furthermore, the EIA may include:......
Paragr.21: As there may some more legitimate uses we propose to insert an “e.g.:” after...proposed programme of extraction.
That is all we have for the moment. We wish you a merry Christmas and a happy New Year.
Ralf Wasserthal - German HOD SEABED CC: Klaus Soentgerath, Dr Birgit Schubert ------
Bundesamt fuer Seeschifffahrt und Hydrographie (BSH) Ralf Wasserthal (M52) Bernhard-Nocht-Str. 78 20359 Hamburg
Tel: 040 3190–3520 Fax: 040 3190–5000 oder -5035 E-Mail: [email protected] ------
90 2002 WGEXT Report
WGEXT ANNEX 8 Appendix F
Mr Kjeld Jorgensen Danish Environmental Protection Agency Ministry of Environment and Energy Strandgade 29 DK-1401 Copenhagen K Denmark
19 December 2001
Dear Kjeld
OSPAR SEABED: WORK ON SAND AND GRAVEL EXTRACTION
At this year’s SEABED meeting it was agreed that Contracting Parties should let Denmark have any comments on the draft guidelines on sand and gravel extraction, and on the draft reporting schedule, by 31 December. The UK does not have any further comments on the guidelines at this stage but we do have some comments on the reporting schedule, which was annexed to SEABED 01/3/2.
Firstly, we would suggest that, for the sake of clarity, the heading of the first column, be amended from ‘Application’ to ‘End use of material’. We do not think that the reference to ‘Beneficial use of dredged material’ is relevant in the context of reporting on sand and gravel extraction, and would therefore suggest that this be amended to ‘Other (please specify)’.
The next column is headed ‘Area’. We suggest that this be changed to ‘Area / region’. For reasons of commercial confidentiality we are unable to provide the data requested for individual licence areas, and would therefore intend to respond on a regional basis.
We suggest deleting the ‘Type’ column and corresponding footnote since it is not clear what additional benefit would be gained from reporting this data. We do not currently collect detailed information of this kind in the UK. In submitting our data we could, however, provide a broad indication of the proportion of the material which is sand and gravel respectively (with regard to ‘Aggregates for construction’, it is usually approximately 60% gravel and 40% sand).
We would also suggest deleting the column headed ‘Depth’ and the corresponding footnote since, again, it is not clear of what use this information would have (it is not data which is currently collected in the UK). In our view, it should be sufficient to provide information on the quantity of material in each category.
With regard to the two ‘Dredging equipment’ columns, we would again question what value this data would have, and would propose that the columns be deleted. Such information is not currently collected in the UK on a systematic basis. In submitting our data we could, however, give a general indication of the types of dredging equipment which are used in UK waters, and the approximate proportions of each.
Finally, we are unsure what the difference is between the last two columns: ‘Amount’ and ‘Total’. It would be helpful if this could be clarified.
We hope that you find these comments useful. The proposed changes would obviously shorten and simplify the schedule but would, we believe, still ensure that the essential data is gathered. We look forward to further discussion on these issues in ICES and at next year’s SEABED meeting.
Yours sincerely, Lewis Baker Lewis Baker Marine, Land and Liability Division
2002 WGEXT Report 91
ICES/WGEXT 2002 SEABED 01/3/3-E (L) Annex 8 Original: English Appendix G English only
OSPAR CONVENTION FOR THE PROTECTION OF THE MARINE ENVIRONMENT OF THE NORTH-EAST ATLANTIC MEETING OF THE WORKING GROUP ON THE USE OF AND IMPACT ON THE SEABED (SEABED) LONDON (SECRETARIAT): 2–4 OCTOBER 2001
Draft OSPAR Guidelines on sand and gravel extraction
Presented by Denmark
Background
1. In the light of ASMO 00/9/4 Denmark did not arrange an IMPACT-Workshop on Sand and gravel Extraction. Instead Denmark invited a sub-group of the ICES WGEXT. The goal of the meeting was to produce draft guidelines for management of marine sediment extraction to be discussed at the ICES/WGEXT meeting in April 2001.
2. After discussion at the ICES/WGEXT meeting new draft guidelines were produced which are attached at Annex 1.
Action requested
3. SEABED is invited to:
a) discuss the draft of guidelines at Annex 1 and send comments or proposals to Denmark for further development of the guidelines;
b) agree that the further development of the guidelines should take place in close cooperation with ICES WGEXT and that a final draft should be submitted to SEABED/BDC in 2002.
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Annex 1
Draft OSPAR Guidelines on sand and gravel extraction
1. The beneficial use of marine aggregates (sand, gravel, stone, boulders and maerl) need to be balanced against the potential negative impacts of the dredging. Dredging activity, if not carefully controlled, can cause significant damage to the seabed and associated biota, to commercial fisheries and to the adjacent coastlines, as well as creating with other users of the sea. In addition, current knowledge of the resource indicates that while there are extensive supplies of some types of marine sand, there appear to be more limited resources of gravel suitable, for example, to meet current concrete specifications and for beach nourishment.
2. It is important to notice that the cornerstone of beneficial use of marine aggregates are development and work within a strategic framework which provides a system for examining and reconciling the conflicting claims on land and at sea and on individual actors or biological parameters of the sea. Decisions on individual applications can then be made within the context of the strategic framework.
3. General principles for sustainable management of all mineral resources overall include:
a) Conserving minerals as far as possible, whilst ensuring that there are adequate supplies to meet the demands of society b) Encouraging their efficient use (re-use), minimising wastage and avoiding the use of higher quality materials where lower grade materials would suffice. c) Ensuring that methods of extraction minimise the adverse effects on the environment, and preserve the overall quality of the environment once extraction has ceased. d) Protecting sensitive areas and industries, including fisheries, important habitats (such as marine conservation areas) and the interests of other legitimate users of the sea. e) Preventing unnecessary sterilisation of mineral resources by other forms of development.
4. The implementation of these principles requires knowledge of the resource an understanding of the potential impacts of its extraction and of the extent to which rehabilitation of the seabed is likely to take place. The production of an Environmental Statement, develop along the lines suggested below, should provide a basis for determining the sensitive to disturbance to justify the extraction of aggregate, and unless the environmental and coastal issues can be satisfactorily resolved, extraction should not normally be allowed.
5. It should also be recognised that improvements in technology may enable exploitation of marine resources from areas of the seabed which are not currently considered as reserves, while development of technical specifications for concrete, etc., may in the future enable lower quality materials to be used for a wider range of applications. In the shorter term, continuation of programmes of resource mapping may also identify additional sources of coarser aggregates.
Scope
6. It is recognised that sand and gravel extraction, if undertaken in an inappropriate way, may cause significant harm to the marine and coastal environment. There are number of international and regional initiatives that should be taken into account when developing national framework and guidelines. These include the Convention on Biodiversity (CBD), EU Directives (particularly those on birds, EIA and habitats) and other regional conventions/agreements, in particular included in Action Plan for Annex V to the 1992 OSPAR Convention on the “Protection and conservation of the Ecosystems and Biological Diversity of the Marine Area” as a human activity requiring assessment.
Administrative framework
7. It is recommended that countries have an appropriate framework for management of sand and gravel extraction and that they define and implement their own administrative framework with due regard to these guidelines. There should be a designated authority to issue permits having fully considered the potential environmental effects, and be responsible for compliance monitoring and the framework for monitoring and enforcing conditions.
2002 WGEXT Report 93
Environmental impact assessment
8. The extraction of sand and gravel from the seabed can have significant physical and biological effects on the marine and coastal environment. The significance and extent of the environmental effects will depend upon a range of factors including the location of the licensed area, nature of the surface and underlying sediment, coastal processes, the design, method, rate, amount and intensity of extraction, and the sensitivity of habitats, fisheries and other uses in the locality. These factors are considered in more detail below. Particular consideration should be given to sites designated under international, European, national and local legislation, in order to avoid unacceptable disturbance or deterioration of these areas for the habitats, species and other designated features.
9. To enable the organisation(s) responsible for licensing extraction to evaluate the nature and scale of effects and to decide whether a proposal can proceed, it is necessary that an adequate assessment of the environmental effects will be carried out. It is important, for example, to determine whether the application is likely to have an effect on the coastline, or have potential impact on fisheries and the marine environment.
10. The Baltic Marine Environment Protection Commission (Helsinki Commission) adopted HELCOM Recommendation 19/1 on 26 March 1998. This recommends to the Governments of Contracting Parties that an EIA be undertaken in all cases before an extraction permit is issued. For EU member states, the extraction of minerals from the seabed falls within Annex II of the “Directive on Environmental Impact Assessment for certain public and private projects” (85/337/EEC). As an Annex II activity, an EIA is required if the member state takes the view that one is necessary. It is at the discretion of the individual member states to define the criteria and/or threshold values that need to be met to require an EIA. The Directive was amended in March 1997 by Directive 97/11/EC. Member states are obliged to transpose the requirements of the Directive into national legislation by March 1999.
11. It is recommended that the approach adopted within the EU is followed. Member states [Contracting Parties] should therefore set their own thresholds for deciding whether and when an EIA is required.
12. Where an EIA is considered appropriate, the level of detail required to identify the potential impacts on the environment should be carefully considered and identified on a site-specific basis. An EIA should normally be prepared for each extraction area, but in cases where multiple operations in the same area are proposed, a single impact assessment for the whole area may be more appropriate, which takes account of the potential for any cumulative impacts. In such cases, consideration should be given to the need for a strategic environmental assessment.
13. Consultation is central to the EIA process. The framework for the content of the EIA should be established by early consultation with the licensing authority, statutory consultant, and other interested parties. Where there are potential transboundary issues, it will be important to undertake consultation with the other countries likely to be affected.
14. As a general guide, it is likely that the following topics considered below will need to be addressed.
Description of the physical setting
15. The proposed extraction area should be identified by geographical location, and described in terms of:
a) the bathymetry and topography of the general area b) the distance from the nearest coastlines c) the geological history of the deposit, including 1) the source of the material 2) type of material 3) sediment particle size distribution 4) extent and volume of the deposit 5) the stability and/or natural mobility of the deposit 6) thickness of the deposit and evenness over the proposed extraction area 7) the nature of the underlying deposit, and any overburden d) local hydrography including tidal and residual water movements e) wind and wave characteristics
94 2002 WGEXT Report
f) average number of storm days per year g) estimate of bed-load, including occurrence of bedforms h) existence of contaminated sediment and their chemical characteristics i) Natural (background) suspended sediment load under both tidal currents and wave action.
Description of biological setting
16. The biological setting of the proposed extraction site and adjacent areas should be described in terms of:
a) the flora and fauna within the area likely to be affected by dredging (e.g., pelagic and benthic community structure), taking into account temporal and spatial variability b) information on the fishery and shellfishery resources including spawning areas with particular regard to benthic spawning fish, nursery areas, over-wintering grounds for ovigerous crustaceans and known routes of migration; c) predator/prey relationships between the benthos and demersal fish populations (e.g., by stomach content investigations); d) Presence of any areas of special scientific or biological interest in or adjacent to the proposed extraction area, such as sites designated under local, national or international regulations (e.g., Ramsar sites, The UNEP “Man and the Biosphere” Reserves, World Heritage sites, Marine protection Areas (MPAs), Marine Nature Reserves, Special Protection Areas (Birds Directive) or the Special Areas of Conservation (Habitats Directive).
Description of the proposed dredging activity
17. The assessment should include, where appropriate, information on:
a) the total volume to be extracted; b) proposed maximum annual extraction rates and dredging intensity; c) expected lifetime of the resource and proposed duration of dredging d) dredging equipment to be used; e) spatial design and configuration of dredging (i.e., the maximum depth of the deposit removal, the shape and area of resulting depression); f) substrate composition on cessation of dredging; g) proposals to phase (zone) operations; h) whether on-board screening (i.e., rejection of fine or coarse fractions) will be carried out; i) number of dredgers operating at a time; j) routes to be taken by dredgers to and from the proposed extraction area; k) time required for dredgers to complete loading l) number of days per year on which dredging will occur; m) whether dredging will be restricted to particular times of the year or parts of the tidal cycle; n) direction of dredging (e.g., with or across tide).
18. While not directly related to environmental impacts, it may be appropriate when known to also include details of the following:
• energy consumption and gaseous emissions; • ports for landing materials; • servicing ports; • on-shore processing and onward movement; • Project related employment.
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Information required for physical impact assessment
19. To assess the physical impacts, the following should be considered:
a) implications of extraction for coastal and offshore processes, including possible effects on beach draw down, changes to sediment supply and transport pathways, changes to wave and tidal climate; b) changes to the seabed topography and sediment type; c) exposure of different substrates d) changes to the behaviour of bedforms within the extraction and adjacent areas; e) potential risk of release of contaminants by dredging, and exposure of potentially toxic natural substances; f) transport and settlement of fine sediment disturbed by the dredging equipment on the seabed, and from hopper overflow or on-board processing and its impact on normal and maximum suspended load; g) the effects on water quality mainly through increases in the amount of fine material in suspension; h) implications for local water circulation resulting from removal or creation of topographic features on the seabed; i) Time scale for potential physical “recovery” of the seabed.
Information required for biological impact assessment
20. To assess the biological impact, following information should be considered:
a) changes to the benthic community structure; b) effects of dredging on pelagic biota; c) effects on the fishery and shell fishery resources including spawning areas with particular regard to benthic spawning fish, nursery areas, over-wintering grounds for oviparous crustaceans and known routes of migration; d) effect on predator/prey relationships between the benthos and demersal fish populations; e) effects on sites designated under local, national or international regulations (see above); f) predicted rate and mode of re-colonisation, taking into account initial community structure, natural temporal changes, local hydrodynamics and any predicted change of sediment type; g) effects on marine flora and fauna including seabirds and mammals; h) Effects on the ecology of boulder fields/ stone reefs.
Interference with other legitimate uses of the sea
21. The assessment should consider the following in relation to the proposed programme of extraction:
a) commercial fisheries; b) shipping and navigation lanes; c) military exclusion zones; d) offshore oil and gas activities; e) engineering uses of the seabed (e.g., adjacent extraction activities, undersea cables and pipelines including associated safety and exclusion zones); f) areas designated for the disposal of dredged or other materials; g) location in relation to existing or proposed licensed aggregate extraction areas; h) location of wrecks and war-graves in the area and general vicinity; i) wind farms; j) areas of heritage, nature conservation, archaeological and geological importance; k) recreational uses; l) General planning policies for the area (international, national and local).
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Evaluation of impacts
22. When evaluating the overall impact, it is necessary to identify and quantify the marine and coastal environmental consequences of the proposal. The EIA should evaluate the extent to which the proposed extraction operation being likely to affect other interests of acknowledged importance. Consideration should also be given to the assessment of the potential for cumulative impacts on the marine environment. In this context cumulative impacts might occur as a result of aggregate dredging at a single site over time, from multiple sites in close proximity or in combination with effects from other human activities (e.g., fishing and disposal of harbour dredging).
23. It is recommended that a risk assessment be undertaken. This should include consideration of worst-case scenarios, and indicate uncertainties and assumptions used in their evaluation.
24. The environmental consequences should be summarised as an impact hypothesis. The assessment of some of the potential impacts requires predictive techniques, and it will be necessary to use appropriate mathematical models. Where such models are used, there should be sufficient explanation of the nature of the model, including its data requirements, its limitations and any assumptions made the calculations, to enable assessment of its suitability for the particular modelling exercise.
Mitigation measures
25. The impact hypothesis should include consideration of the steps that might be taken to mitigate the effects of extraction activities. These may include:
a) the selection of dredging equipment and timing of dredging operations to limit impact upon the biota (such as birds, benthic communities and fish resources); b) modification of the depth and design of dredging operations to limit changes to hydrodynamics and sediment transport and to minimise the effects on fishing; c) spatial and temporal zoning of the area to be licensed or scheduling extraction to protect sensitive fisheries or to respect access to traditional fisheries; d) preventing on-board screening or minimising material passing through spillways when outside the dredging area to reduce the spread of the sediment plume; e) Agreeing exclusion areas to provide refuges for important habitats or species, or other sensitive areas.
26. Evaluation of the potential impacts of the dredging proposal, taking into account any mitigating measures, should enable a decision to be taken on whether or not the application should proceed. In some cases it will be appropriate to monitor certain effects as the dredging proceeds. The EIA should form the basis for the monitoring plan.
Environmental Monitoring
27. Sand and gravel extraction inevitably disturbs the marine environment. The extent of the disturbance and its environmental significance will depend on a number of factors. In many cases it will not be possible to predict, in full, the environmental effects at the outset, and a programme of monitoring may be needed to demonstrate the validity of the EIA's predictions, the effectiveness of any conditions imposed on the permit, and therefore the absence of unacceptable impacts on the marine environment.
28. The level of monitoring should depend on the relative importance and sensitivity of the surrounding area. Monitoring requirements should be site specific, and should be based, wherever possible, on the findings of the EIA. Being cost effective, monitoring programmes should have clearly defined objectives derived from the impact hypothesis developed during the EIA process. The results should be reviewed at regular intervals against the stated objectives, and the monitoring exercise should then be continued, revised, or even terminated.
29. It is also important that the baseline and subsequent monitoring surveys take account of natural variability. This can be achieved by comparing the physical and biological status of the areas of interest with suitable reference sites located away from the influence of the dredging effects, and of other anthropogenic disturbance. Suitable locations should be identified as part of the EIA's impact hypothesis.
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30. A monitoring programme may include assessment of a number of effects. When developing the programme a number of questions should be addressed to include:
a) what are the environmental concerns that the monitoring programme seeks to address; b) what measurements are necessary to identify the significance of a particular effect; c) what are the most appropriate locations at which to take samples or observations for assessment; d) how many measurements are required to produce a statistically sound programme; e) What is the appropriate frequency and duration of monitoring?
31. The permitting authority is encouraged to take account of relevant research information in the design and modification of monitoring programmes.
32. The spatial extent of sampling should take account of the area designated for extraction and areas outside which may be affected. In some cases, it may be appropriate to monitor more distant locations where there is some question about a predicted nil effect. The frequency and duration of monitoring may depend upon the scale of the extraction activities and the anticipated period of consequential environmental changes, which may extend beyond the cessation of extraction activities.
33. As information on the effects of marine dredging becomes more available and a better understanding of impacts is gained, it may be possible to reduce the level of monitoring necessary. It is in the interest of all concerned that monitoring data is made widely available. Reports should detail the measurements made results obtained their interpretation and how these data relate to the monitoring objectives.
Monitoring compliance with licence conditions
34. An essential requirement for the effective control of marine aggregate extraction is monitoring on a continuous basis of all dredging activity to provide a permanent record. This can be achieved in several ways, e.g., an Electronic Monitoring System or Black Box. The information provided will allow the regulatory to monitor the activities of dredging vessels to ensure compliance with particular conditions in the permission.
35. The information collected and stored will depend on the requirements of the individual authorities and the regulatory regime under which the permission is granted, e.g., EIA, EU Habitats and Birds Directives of the EU.
36. The minimum requirements for the monitoring system should include:
a) an automatic record of the date, time and position of all dredging activity; b) position to be recorded to within a minimum of 100 metres in latitude and longitude or other agreed coordinates using a satellite-based navigation system; c) there should be an appropriate level of security; d) The frequency of recording of position should be appropriate to the status of the vessel, i.e., less frequent records when the vessel is in harbour or in transit to the dredging area, e.g., every 30 minutes and more frequent when dredging, e.g., every 30 seconds.
37. The above are considered being reasonable minimum requirements to enable the regulatory authority to monitor the operation of the licence in accordance with any conditions attached. Individual countries may require additional information for compliance monitoring at their own discretion.
38. The dredging company to improve utilisation of the resources can also use the records. The information is also an essential input into the design and development of appropriate environmental monitoring programmes and research into the physical and biological effects of dredging, including combined/cumulative impacts (see Section above).
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ANNEX 9: EFFECTS OF SAND AND GRAVEL EXTRACTION ON SENSITIVE MACROBENTHIC SPECIES IN THE SOUTHERN BALTIC SEA
J. C. Krause, E. Körner and G. Arlt
Presentation at the meeting of ICES WGEXT in Boulogne-sur-Mer, 10.04.2002.
Present address of the first author: Ernst-Moritz-Arndt University of Greifswald, Institute of Ecology, Plantecology, Grimmerstr. 88, 17489 Greifswald, Germany
Introduction
Since the 1990s the amounts of sand and gravel extracted in the southern Baltic Sea have continuously increased (HELCOM 1999). To assess the effect of the dredging activity on sensitive macrobenthic species in the region a joint project from the Federal Agency of Nature Conservation (BfN) and the University of Rostock, partly funded by the Federal Foundation for the Environment (DBU) was conducted. This paper summarises some of the results that will be published as a thesis of the University of Rostock in the near future.
The study was divided into two field assessments and one investigation using laboratory experiments.
First (study 1), because of a lack in benthic monitoring data directly from the areas permitted for dredging, an assessment of benthic macrozoobenthos communities was conducted. Additionally we analysed which of the identified inhabitant species can be considered as sensitive to the effects of dredging by first identifying composition indicator species (Dufrene and Legendre 1996) and then separating from these, species sensitive to the effects of seabed disturbance according to “sensitivity” criteria emphasised by ICES (1994, 1995).
Second (study 2), we followed and documented physical and chemical alterations and consequent changes of the macrobenthic community after a typical sand extraction used for beach replenishment on behalf of the local authorities. In particular, the population dynamics of species, which were identified in study (1) as sensitive, were analysed.
In the final step (study 3) we examined under laboratory conditions, which of the documented physio-chemical alterations are the crucial variables that determine the potential negative effect on sensitive species.
Methods
Study 1: Sediment samples and macrobenthic invertebrates were collected using a “van Veen” grab according to HELCOM monitoring standards. Distinct community groups were separated by common clustering and ordination methods, i.e., Cluster analysis (CA), principal component analysis (PCA), non-metric multidimensional scaling (MDS) and canonical correlation analysis (CCA). Additionally abiotic characteristics of the sediment and the adjacent water column were measured, e.g., grain size, organic content, salinity, oxygen concentration, etc. For each community, typical species, so-called composition indicators, were separated as the most structured faunal elements of the community.
The identified composition indicators were assessed on “sensitive” or “non-vulnerable” life history traits and population characteristics. Finally, we distinguished between “potentially affected areas” and “resilience areas”. “Potentially affected areas” were defined as areas inhabited by communities having indicator species, which can be characterised as “sensitive species”. Additionally, a high percentage of red list species should be recorded for the area. “Resilience areas” were defined vice versa, i.e., the indicator species are “non-vulnerable species” and red list species were collected in the area.
Study 2: Beside a rather long tradition in the western and southern Baltic Sea in analysing the resettlement of benthic communities, only a few studies have investigated the effect of bottom trawling and even fewer studies have described the effects of commercial dredging on benthic habitats. Alterations of the seabed topography and morphology were measured using echo-sounding and side-scan sonar. Oxygen concentration, salinity and temperature of the water column were measured using specific sensors in connection with CTD. Using a “van Veen” grab and SCUBA divers, controlled core sediment samples had been taken to analyse the abiotic parameters grain size, organic content, oxygen and sulphide concentrations and to identify the macrobenthic invertebrates living in the sediment, their abundance and biomass.
Study 3: Three experiments were conducted to examine the effect of the alterations of the abiotic parameters identified in study 2 on the Travisia forbesii. This polychaete was sampled during the 1990s only in areas, that were permitted for
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extraction and was also identified as a sensitive species. We investigated the ability of T. forbesii to discriminate between sediments from a control area and from the bottom of dredging furrows. In another set of experiments we examined the metabolic response and physiological flexibility on oxygen depletion. Finally we observed the “surfacing behaviour” as a response to decreasing oxygen and increasing sulphide concentrations in the sediment.
Results
Study 1: Along the salinity gradient of the southern Baltic Sea (18 to 7 psu) in the areas planned for sand and gravel extraction, four different groups of communities were differentiated according to the abundance of 118 macrozoobenthic taxa. These groups were also significantly described by a total of 35 composition indicator species. From these composition indicator species, 18 were assessed as sensitive to the effects of sediment disturbance, following the ICES criteria (1994, 1995). The other 17 species were considered as non-vulnerable. Areas of different degrees of sensitivity to the effect of sand and gravel could be grouped and ranked by the composition and condition indicator species of the very community.
Figure A9.1. Distribution map of the four communities identified living in the areas planned for extractions in the southern Baltic Sea.
Longitude (East) 11.00 11.50 12.00 12.50 13.00 13.50 14.00 14.50
A d le Plantagenet Ground r G ro u n s d rs a 54.50 D Prerow Bank ) f h o t Zingst s e
(Nort W Wustrow
ude Stralsund t Lati ay r B isma Neustadt W Rostock Greifswald
54.00 Travemünde Swinoujscie Wismar Legend Sample locations grouped Town according to the result of the CCA Baltic Sea A B C D Landscape Border German EEZ Sediment Extraction Areas
Figure A9.2: Summed indicator values of non-vulnerable, sensitive, and red list species for the four macrobenthic communities living in the areas planned for extraction in the southern Baltic Sea.
sensitive species 7 500 non-vulnerable species 6 s
ie 400 red list species c e p 5 `IV´ s
e r lu o
a 300 4 cat r v di o t a in
3 c
di 200 ve´ i sit
2 m in u en s s 100 # ` 1
0 0 ABCD ABCD
community cluster community cluster
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Study 2: Side-scan sonar images show three types of dredge head tracks in the sediment, i.e., holes of up to more than 20 m in diameter and three to four metres deep, solitary well-defined furrows with a mean depth of 0.5 m and width of 2 m, and multiple track furrows creating deeper channels as part of an overall deepening. These channels were at an average more than 3 m deep and 5 m wide. During two side-scan sonar measurements four and ten months after extraction, the track marks had eroded or refilled considerably. In the dredged box, the mean number of track marks was reduced from 6.5 to 2.6, the furrows became smaller from 4.6 m to 3 m and shallower from 1.4 m to 0.9 m. The change was significantly less in the most impacted area, where the number of tracks was also reduced; nevertheless, they broaden up to 8 m width and after ten months were still more than 3 m deep.
In the heavily impacted area, four major alterations of the sea bottom sediment were measured: there was finer grain size with a higher organic content, with a smaller oxygenated and redox discontinuity but a growing reduced layer closer to the sediment surface. Ten months after dredging oxygen depletion was recorded in the deeper furrows. This alteration had a significant, but local and only short-term effect on the community. As a matter of fact, these alterations seemed to have only a minor effect on the common macrobenthic species (e.g., Nereis (Hediste) diversicolor, Macoma balthica, Mytilus edulis) but a more severe effect on the sensitive composition indicator species (e.g., Travisia forbesii, Bathyporeia pilosa, Mya arenaria) which were not sampled in the impact area during the thirteen months the area was observed after dredging.
Figure A9.3. Number of dredge marks identified on side-scan images six and ten months after dredging of an extraction 2 n.m. offshore of the coast of Darss-Fischland, German Baltic Sea.
A four month after dredging B ten month after dredging
54.222 54.222
54.218 54.218
number of track marks number of track marks 1-5 16-20 54.214 1-5 16-20 54.214 6-10 21-25 6-10 21-25
11-15 > 25 11-15 > 25
no track marks no track marks
no data in the extractionfeld no data in the extractionfeld 54.210 border of the extractionfeld 54.210 border of the extractionfeld
500 1000 m 5 30 2 210 215 220 225 2 210 215 220 2 230 2. 2. 12. 12. 1 12. 12. 12. 1 12. 12. 12.
Study 3: All four major alterations tested had negative effects on the behaviour or physiology of T. forbesii. Nevertheless, T. forbesii can cope with physiological tolerances to: • a shift to finer grain size; • higher organic content; • a reduction of the oxygenated and the redox discontinuity layer.
However, when the reduced sediment layer moved towards the surface, thus increasing the sulphide concentration to more than 1.0 mmol l−1, all tested animals hauled out of the sediment or died.
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Figure A9.4. Percentage of individuals of T. forbesii hauling out of the sediment under control conditions (no change), oxygen depletion for 12 hours (middle, grey box) and increasing sulphide concentration (bottom, first grey box initial rising of the sulphide concentration to 0.5 mmol l–1, and 1.0 mmol l–1 second grey box).
1 Control 0.8 0.6 0.4 0.2 e c
a 0 surf 0 1020304050 nt e 1 Oxygen depletion 0.8
sedim 0.6 0.4 ls on 0.2 dua i 0 div 0 1020304050 % in 1 Increasing Suphide 0.8 0.6 0.4 0.2 0
0 1020304050
Time (h)
General conclusions
The effect of sand and gravel extraction is assessed to be only local and short-lived for the common omnipresent macrobenthic species of the southern Baltic Sea. However, there is a considerable stress potential for species being both indicators for composition and condition (i.e., sea bottom disturbance) in their specific habitats. The negative effects seemed to be mostly due to the alteration of sandy turbulent areas poor in organic content, to stagnant areas with finer sediments enriched in organic content, which leads to increasing sulphide concentrations in the sediment and local oxygen depletions. Thus sediment extraction can locally add to the overall impacts, in combination with eutrophication. In case of one sensitive species, T. forbesii, it could be demonstrated that the total regional distribution of this species is endangered due to the alterations of the seafloor post dredging.
When assessing anthropogenic impacts in coastal areas of estuarine character, the species composition has to be carefully analysed before using general analytical tools. We emphasise the need to assess with dual measures. One, for the effect on the common species well adapted to all kinds of natural disturbances and therefore also to human impacts. And an additional measure, specifically tailored for less abundant, but still typical and sensitive species of the region.
There is a fundamental need for regional planning in the coastal waters of the southern Baltic Sea. The number of actual and intended commercial activities in the offshore habitats means that local environmental impact assessment is becoming less suitable to forecast the effects on the impacted flora and fauna in the total region.
Dredging activity itself should be subject to greater controls, to avoid overall deepening greater than 1 m and the overlaying of dredging furrows. The selection of sites in space and time has to consider the distribution of important habitats for sensitive composition indicator species, forming the individual character of their communities, and additionally, of other human activities that threaten the same species at the same time in other associated populations.
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Future investigations, should identify the population distribution of the other sensitive species and promote the understanding of the life history traits and population dynamics of these species. References
Dufrene, M., and Legendre, P. 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecological Monographs, 67(3): 345–366.
HELCOM. 1999. Marine sediment extraction in the Baltic Sea – status report. Baltic Sea Environment Proceedings No 76: 1–31.
ICES. 1994. Indicator species with reference to physical disturbance of the seabed. ICES Cooperative Research Report No. 204: 55–57.
ICES. 1995. Indicator species sensitive to physical disturbance of the seabed. ICES Cooperative Research Report No. 214: 102–103.
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ANNEX 10: EFFECTS OF EXPLOITATION OF MARINE RESOURCES ON EPIFAUNAL SUSPENSION- FEEDERS
Introduction
The purpose of this project is to demonstrate and assess potential effects of suspended and settled material on selected benthic suspension-feeders due to exploitation or other digging activities in the seabed. The focus is on suspension- feeders from hard substrata habitats, as it is assumed that they are rarely exposed to high loads of suspended material and thus less tolerant compared to the soft-bottom fauna.
In 1996 NERI, in collaboration with the Danish Forest and Nature Agency, DFNA (Skov- og Naturstyrelsen), and the Geological Survey of Denmark and Greenland (GEUS), measured concentrations of suspended material in wastewater and from several positions downstream from a vessel collecting pebble. The results from these measurements and the present study are integrated in the discussion.
Background
Exploitation of marine resources has taken place for many years. In Denmark approximately 6 million m3 material is excavated per year (1987–1999). The material is used to make concrete, roads or sand for breakwaters and fillings. The yearly output has varied between 3.6 million m3 and 12.8 million m3 with the largest amounts during the development of the Great Belt Bridge in 1989–1991, the Øresund Bridge 1996/1997 and the expansion of the harbour of Århus in 1999. 99 % of the material collected in 1999 was sand and gravel (Statistiske Efterretninger, 2000).
When exploiting marine resources, conservation and protection of important or sensitive areas need to be addressed. It is thus for DFNA to set the conditions and issue permits prior to excavation activities.
The knowledge of effects on epifauna and hard substrata species from excavation and digging activities is very limited (Hygum, 1993; Kiørboe and Møhlenberg, 1982). Previous studies of suspended material have focused on bivalves, mainly adult mussels, and the results show that they are capable of coping with extremely high concentrations of suspended material (Kiørboe et al., 1980; Petersen, 1993). Increased growth rate was found at moderate concentrations in one study with mussels (Kiørboe et al., 1981). From these studies it has been deduced that in general there are limited effects on suspension-feeders from exploitation activities.
However, mussels and other bivalves are probably not suitable key species for benthic suspension-feeders. It has been shown that bivalves are capable of compensating for negative effects of suspended material by particle selection (Kiørboe and Møhlenberg, 1981). Particle selection is not achievable for many other suspension-feeders, e.g., ascidians, bryozoans, suspension-feeding polychaetes and sponges. Also, these organisms differ from bivalves by being completely immobile and do not have the same protective measures like the bivalve shells. Thus, these organisms are potentially affected more by suspended material than bivalves.
The Experiments
Through different experiments in the laboratory and in situ, it was the purpose of this study to investigate effects on suspension-feeders of increased levels of suspended and settled material as experienced during exploitation activities. Three types of experiments were performed. In the “catastrophe event” three 2 m2 areas of the seabed were covered with material, as would happen in the near vicinity of the exploited field and changes in the fauna assemblages were monitored. Potential effects of suspended material were observed through different types of experiments. Two types of experiments were performed in order to reveal any immediate effects. Clearance rate (ml min−1 of water cleared for particles) was measured and behaviour (actively feeding or inactive) was monitored of suspension-feeders during 1–2 days of exposure to increased concentrations of suspended material. To demonstrate any long-term effects, growth rates were measured in experiments lasting seven days.
Results
The highest concentrations and largest particles were used in the “catastrophe event” experiment, where three plots (1 × 2 m2) were covered with 5 cm of sand with a particle size of 0.1–0.3 mm. The layers covered small rocks and horse mussels and thus all epifauna covering those surfaces. The sand stayed for several months and even though horse mussels and sea anemones are mobile, several horse mussels and their associated fauna died. One year after the event, the sand had been resuspended but a difference in the fauna assemblage was still apparent compared to the surroundings (three 1 × 2 m2 control plots). Experiments with smaller particles and lower concentrations were performed in the
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laboratory. Particles with a diameter of 63–125 µm were used in a study of behaviour/mortality of bryozoans and ascidians. No mortality was found within 48 hours with turbidity ranging between 8 and 15 NTU (Nephelometric Turbidity Units), but zooids of bryozoans reacted by retracting more frequently (15 times per hour compared to approximately 2 times per hour) and thus being inactive for longer periods (70 % activity compared to 98 %). In a similar study using particles of <63 µm in diameter, no effects were found for bryozoans.
The smallest particle fraction was also used in clearance rate studies with sponges, ascidians and horse mussels. Ascidians and horse mussels showed a decrease in clearance rate with turbidity ranging between 6 and 10 NTU. To study if the decreased clearance rate had long-term effects, growth rates of colonial ascidians and bryozoans were measured. After seven days of exposure to approximately 10 NTU both groups were growing fine, and showed no sign of decreasing growth.
Discussion
The experiments in this project show some of the effects from exploitation activities. In order to assess the extent of effects on suspension-feeders the results have to be related to measurements of suspended particles from actual exploitation activities. Measurements of concentrations of suspended material in wastewater and from several positions downstream from a vessel collecting pebble were performed at Læsø Trindel in the northern part of Kattegat. A model was developed based on the results, showing concentration and size of settled particles as a function of distance from the source (Skov- og Naturstyrelsen, 1996; Møhlenberg and Jensen, 1997). The model showed that the majority of particles settled within 200 metres, and only particles smaller than 150 µm stayed in the water column and were transported further away.
In the clearance rate and behaviour experiments, the maximum concentration was around 10 NTU, which in this study is equivalent to 30 mg l−1. In the Læsø measurements these concentrations were found 100–300 metres from the vessel. In this range ascidians and horse mussels are affected and lower their clearance. The median diameter of particles in this area is 125 µm, thus bryozoans will also be affected and lower their activity.
The model showed that the particle concentration 600 metres downstream from the vessel is around 5 mm3 l−1 and particles are in the size range of 1.5–50 µm. Assuming a size-spectra similarity between the particles from the laboratory experiments and the Læsø Trindel, 5 mm3 l−1 equals 7–8 mg l−1. At these concentrations effects are still seen as decreased clearance rates of ascidians and horse mussels. The particles are in the smallest fraction and would not lead to disturbance in the behaviour of bryozoans or to decreased growth due to long-term exposure. However, it is important to know what the particle size is 600 metres from the vessel. Mikkelsen and Pejrup (2000) showed that particles had flocculated 1,500 metres downstream from a digging vessel. With the observed current velocity it took approximately 50 minutes for the particles to travel this distance and the 9 µm particles made flocculates of an average diameter of 109 µm. The density of the particles decreased from 2.390 kg m−3 to 1.501 kg m−3. Thus the settling velocity had only decreased 1.5 times despite the huge difference in particle diameter, and the flocculates were still in the water column. In the Læsø measurements the current was weaker, and particles took approximately 75 minutes to travel 600 meters. It has been shown that if measurements are taken on a Coulter Counter particle counter, aggregates larger than 7–25 % have been destroyed at the orifice (Mikkelsen and Pejrup, 2000). If the same happens when using an Elzone particle counter, then the particles from Læsø might have formed larger flocculates than indicated in the study as an Elzone particle counter mounted with a 76 µm or a 95 µm orifice tube was used. If the flocculation phenomenon took place, then particle suspension 600 metres from the vessel would affect the behaviour of bryozoans.
600 metres from the vessel at Læsø Trindel, the highest particle concentrations of 1.5–50 µm particles were at 5 to 7 metres of depth. In the area it was 12 metres to the bottom, and the particles would therefore be able to travel another 600 metres before settling. However, it is practically impossible to give a general indication of how far the smallest particle fractions would be able to influence suspension-feeders, as it depends highly on the current velocity and depth in the area.
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Figure A10.1. Effects on suspension-feeders found in this project related to a model for suspended material from Læsø Trindel.
0,2s 5 change in f auna assemb lage er change in behavio ur of bryozo ans
ed r ed uce d cl ear an ce r at e o f as ci d i an s and h o rs e mus sel s
0,e 2 f - n o i
0,1s 5 n e p
0,s 1 u s
0,05 on s t c
e 0 f 0 ef 200 400 600 800 000 1
distance from vessel, meters
The different experiments with epifaunal suspension-feeders show short-term effects (hours) up to 1.2 km from exploitation activities, and long-term effects (months/years) on fauna in near vicinity of the vessel (Figure A10.1). The extent of the long-term effects on epifauna depends on the duration of the activities. In the observations from Læsø Trindel, 80 % of the suspended material settled within 50 metres from the vessel in a 30-metre wide tail (Møhlenberg and Jensen, 1997). The dry weight of the suspended material was between 27 and 45 g l–1 (Skov- og Naturstyrelsen, 1996). With a content of 36 g l–1 and a pumping rate of 2,500 m3 hour−1, 90 tonnes of material would be suspended in one hour. If 80 % of this material is deposited in a (50 m × 30 m) 1,500 m2 area, it would on average result in a 2 cm thick layer of settled particles (density set to 2,600 kg m−3). This is in good agreement with diver observations immediately after one hour of suction activities at Læsø Trindel. In the “catastrophe event” experiment a 5 cm layer of sand was deployed. i.e., after 2–3 hours, similar effects to those found in the “catastrophe event” experiment in a 1,500 m2 area were observed. At Læsø Trindel, a total of 3 hours of suction resulted in 120 m3 of useful material, i.e., for every 1 m3 collected 10 m2 of seabed would be covered with suspended material, which as shown in the “catastrophe event” experiment would still be affected a year later. How long the settled particles stay before resuspension, and thus how severely they affect the epifauna, depends on if/when the wind and current would be able to resuspend the material. The energy transfer from wind to waves and currents depends on the stretch available for the wind to act on the water’s surface. In an enclosed sea as the Kattegat, the direction of the wind is of great importance in determining wave amplitude and thus the depth at which the wave movement is capable of resuspending material. Floderus (1988) produced a model, which divided the Kattegat into 5 × 5.5 mile squares. He was then able to calculate how often resuspension occurred in each square, depending on force and direction of the wind, and the water depth. In the area around Schultz Grund where the “catastrophe event” experiment took place, resuspension was found to occur 0.1–2 % (0.5–7 days year−1). In the area around Læsø Trindel it occurred 40–100 % (146–365 days year−1). However, it is very difficult to make satisfactory models of the particle size of material that is resuspended and the frequency of its transport (Floderus, 1988; Møhlenberg and Jensen, 1997; Skov- og Naturstyrelsen, 1991). Furthermore, even large stones were found to be moved if stuck to macroalgae holdfast from, e.g., Laminaria, whose leaves can serve as “sails” in the current.
Conclusion
There are short and long-term effects on epifaunal suspension-feeders when exploiting marine sediments. Effects are most severe near the vessel (<100 metres) either from direct influence of the suction pump or other equipment, or due to heavy load of settled material. In this area it would take months/years for the fauna to recover, unless the habitat is irreversible altered. The “catastrophe event” experiment in combination with a model deduced from several exploitation activities at Læsø Trindel indicates that 10 m2 of seabed is affected for every 1 m3 of material collected. Resuspension of the settled material and thus the recovery of the area depend on water depth and the exposure to wave action and currents.
Suspension-feeders within 1–1.5 kilometres downstream of a vessel would be affected short-term. Effects include changed behaviour, reduced activity or reduced clearance rate. In this range no long-term effects were found in this study.
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References
Floderus, S. 1988. On the spatial distribution of wave impact at the Kattegat seabed, - Geogr. Ann. 70A: 269–272.
Hygum, B. 1993. Miljøpåvirkninger ved ral- og sandsugning. – Et litteraturstudie om de biologiske effekter af råstofindvinding i havet. Danmarks Miljøundersøgelser. Faglig rapport fra DMU nr. 81.
Kiørboe, T., and Møhlenberg, F. 1981. Particle selection in suspension-feeding bivalves. Mar. Ecol. Prog. Ser. 5: 291– 296.
Kiørboe. T., and Møhlenberg, F. 1982. Sletter havet sporene? – En biologisk undersøgelse af miljøpåvirkninger ved ral- og sandsugning. Miljøministeriet, Fredningsstyrelsen. 95 pp.
Kiørboe, T., Møhlenberg, F., and Nøhr, O. 1980. Feeding, particle selection and carbon absorption in Mytilus edulis in different mixtures of algae and resuspended bottom material. Ophelia 19(2): 193–205.
Kiørboe, T., Møhlenberg, F., and Nøhr, O. 1981. Effect of suspended bottom material on growth and energetics in Mytilus edulis. Mar. Biol. 61: 283–288.
Mikkelsen, O., and Pejrup, M. 2000. In situ particle size spectra and density of particle aggregates in a dredging plume. Marine Geology 170: 439–455.
Møhlenberg, F., and Jensen, J.N. 1997. Spredning og sedimentation af partikulært materiale under råstofindvinding ved Læsø Trindel. Delrapport 2. Undersøgelse og effektvurdering, maj 1996. 19 pp. Arbejdsrapport fra DMU nr. 61.
Petersen, A.H. 1993. Effekter af suspenderet kalkmateriale på blåmuslingers vækst, kondition og klorofylindhold. Intern rapport fra Danmarks Miljøundersøgelser. 25 pp. Afd. For Havmiljø og Mikrobiologi.
Skov- og Naturstyrelsen. 1991. Sandsugning og det fysiske miljø. Hav-serien nr. 1. Miljøministeriet. 56 pp.
Skov- og Naturstyrelsen. 1996. Spildmålinger ved Læsø Trindel. Delrapport 1. Prøveindsamling og analyseresultater. J. nr. 1996–714–0011.
Statistiske Efterretninger. 2000. Råstofindvindingen i Danmark i 1999. Statistiske Efterretninger. Miljø 2000:19.
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ANNEX 11: ENGLISH SUMMARY OF THE REPORT “BIOLOGICAL SCREENING OF EXTRACTION AREA FOR PEBBLES AND SAND SUCTION BY DIVE AND SONAR”
Figure A11.1 View from the investigation area.
INTRODUCTION
Hedeselskabet has developed a concept for screening of exposed near field in connection with construction works, i.e., marine aquaculture, off-shore wind farms, extraction of raw materials, etc., in coastal zone areas. The method includes paravane dives (visual inspection by a diver drawn after a boat in a transect survey) for registration of different parametres in the sea floor (water depth, fauna and flora at species, substratum etc.). The concept includes software for positioning of the diver, presentation of data as interpolated GIS-maps, report and positioned video and/or underwater pictures as visual documentation and data storage, all provided on a CD to be used on your own PC.
The biological screening is in many cases sufficient to describe a baseline for the investigation area or to determine a possible need for further detailed surveys in the area. The biological screening is optimal regarding cost-benefit, and the method is approved by the National Environmental Research Institute to be used in the Danish national surveillance programme and by the National Forest and Nature Agency for investigation of areas for extraction of raw materials. At depths less than 20 metres, areas of approximately 2 km2 can be covered for each day of survey – in Denmark, at a total cost including video/pictures and reporting below USD 7000/2km2.
In connection with an extraction of raw material of pebbles and sand from the seabed, the Danish Forest and Nature Agency has requested an assessment of impacts on the physical and biological conditions of the seabed in an extraction area. It was decided to prepare the assessment in accordance with the concept for screening of exposed near fields elaborated by Hedeselskabet. Furthermore, the area was selected as a testing ground for the applicability of side-scan sonar to assess the area for the same conditions. The side-scan sonar investigation was made in close cooperation between Hedeselskabet and GEO. Furthermore the depth condition of the seabed is described by means of multibeam sonar.
Consequently, this investigation is a development study to evaluate underwater search and sonar search as environmental evaluation tools for areas to be used for raw material extraction. However, the evaluation and recommendations can be extended to all other activities that expose the coastal waters to environmental impacts.
The biological screening has been proven against photo-monitoring, side-scan sonar and multibeam sonar. The biological screening has been found to provide higher quality information by less expensive means than photo- monitoring and sonar survey with regard to the physical and biological investigations, while bathymetry mapping is far more detailed if conducted by the multibeam sonar.
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METHODS
“Paravane diving”
Seabed observation by means of “paravane diving” was made by dragging a diver across the seabed at low speed and the diver’s observation was communicated to the surface crew. The dives were made by marine biologists who were drawn approximately 50 metres behind the research vessel at a speed of 1–2 knots. In this way it was possible to register the distribution of eelgrass, common mussels, etc., along the investigated transects. The different parametres were continuously visually estimated along the transect in a width of 6–10 metres and at changes in registered parametres or at suitable intervals the observations were reported and registered together with the diver’s position. For diver positioning and logging of the diver’s observations, D-GPS equipment, connected to specially developed software (Paravane ver. 1.02, Hedeselskabet), was used.
Figure A11.2 Paravane transects in the survey area.
At each observation the following parametres were registered:
• Water depth (registered by the diver by reading a diving computer, precision ± 10 cm); • Algae cover (loose-lying or sessile red-green or brown algae, estimated in percentage of the total bottom area); • Cover of suited substratum for larger macroalgae (stones > 20 cm estimated in percentage of the total bottom area); • Cover of suited substratum for smaller macroalgae (stones 10–20 cm estimated in percentage of the total bottom area); • Cover of unsuited hard substratum for macroalgae (pebbles 2–10 cm, common mussels and shells estimated in percentage of the total bottom area); • Cover of common mussels (estimated in percentage of the total bottom area); • Cover of suited substratum for eelgrass (soft bottom estimated in percentage of the total bottom area); • Cover of eelgrass (estimated in percentage of the total bottom area).
Stones larger than 10 cm are in Danish waters normally considered suitable substratum for perennial growth of macroalgael. In a comparison between diver’s observations and side-scan sonar interpretations, it is necessary to
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differentiate between stones larger and smaller than 20 cm as it is impossible to register stones < 20 cm as measurable single stones on the sonar mosaic.
Survey by means of sonar
The survey of the seabed was made by sailing across the bottom with three different acoustics systems: precision depth sounder for bathymetry, side-scan sonar for the bottom’s structural topography and sub-bottom profiler for a seismic profile through the sediment. The three sonar systems have different qualities and each shows different characteristics of the seabed. All systems were used at the same time with an exact determination of the position of each sonar system. The speed of the boat during the survey was 3–4 knots.
Side-scan sonar data
Data have been registered at a 25-m range and an “input Voltage” of 1.25 V.
During the whole survey the aim was to have the side-scan “fish” placed 10–15 % of the range over the seabed equal to approximately 3 m. This gives a coverage of 85–90 %, as a small band, directly below the “fish”, cannot be registered. Data are collected and stored on magnetic optical disk in Coda format. The echo signals are mapped with true geographic position and create a mosaic (a sonar graph) that forms the basis of the interpretation.
Sub-bottom profiler data
The collected sub-bottom profiler data are, in this survey, used as an aid for the interpretation of sonar data, i.e., there has been no actual interpretation of data but in some cases, the sub-bottom profiler data have been used to decide the top of the alluvial plain. A single line in the southern part of the area has been interpreted. The interpretation shows that the thickness of the sand layer is largest in the northeastern part.
Biological evaluation by means of side-scan sonar
All interpretations of the side-scan sonar were made based on the mosaic. In some cases it was necessary to investigate the single line to have a larger resolution for better details. The interpretation of the mosaic concerns boundaries between areas with different characteristics. No single objects have been identified.
THE RESULTS OF PARAVANE DIVES
The results of the paravane dives have been presented in GIS-interpolation plots. The following parameters are presented:
• Depth, resolution 25 cm (Figure A11.3); • Cover of total occurrences of stones, stones from 2 cm to approximately 200 cm, resolution 10 % (Figure A11.9); • Cover of common mussels, resolution 10 % (Figure A11.5); • Cover of eelgrass, scale 0, <1, 1, 5, 10 % (Figure A11.7); • Cover of macroalgae, scale 0, <1, 1, 10, 20, 30, 40, 50, 60, 70, 80, 90 %.
Conclusion of diver’s observation
The “biological value” of the survey area, based on this screening, is that the central shallow part of the area is suitable for common mussels and eelgrass.
In the southwestern part of the survey area a stone reef area was found. The reef stretches along the southwestern boundary of the survey area. The cover of macroalgae was as high as 80 %. Furthermore, the macroalgae vegetation was varied and dominated by different red algae.
THE RESULTS OF THE SONAR SURVEY
On the basis of the sonar graph it was difficult to distinguish between areas covered with mussels or smaller stones as the reflectivity is almost alike. If larger stones are covered with mussels the very strong reflection from hard seabed overrules the signal from the mussels.
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When stones are covered with dense algal vegetation it might be difficult to perceive objects that lie below the vegetation, i.e., mussels. Areas consisting of only one type of hard substratum are the most unambiguous to classify.
Based on the structural differences in the sonar graphs the extraction area was interpreted by reviewing the distribution of the different parameters. Four different bottom types were identified: mussels, eelgrass, stones (> 20 cm), and macroalgae. Furthermore, each bottom type was classified according to cover. A fifth bottom type was used in areas without structural information. This bottom type was classified as sand.
Conclusions of the sonar survey
The “biological value” of the survey area, based on diver-calibrated side- scan sonar survey, is as follows:
• A good bathymetry (depth model) has been described (Figure A11.4); • Based on the diver calibration a good area delimitation of common mussels and eelgrass occurrences has been made, with a poorer resolution of cover than those made by paravane dives; • The occurrences of macroalgae are extremely difficult to estimate; • In the southwestern part of the survey area a stone reef was observed. The reef area is partly outside and partly inside the southwestern boundary of the survey area; • It was not possible to distinguish pebbles from mussels without diver observations.
DISCUSSION AND CONCLUSION – COMPARISON BETWEEN PARAVANE DIVES AND SONAR SURVEY
Bathymetry
Figure A11.3 Depth of water conditions, paravane dives.
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Figure A11.4 Depth of water condition, multibeam sonar.
Investigation of bathymetry (depth model) leads to the following main conclusions: • Multibeam sonar gives a very good description of the depths of the area with a precision of < 10 cm; • Paravane dives outline the depths well; • The precision in the present survey areas for paravane dives is approximately 50 cm.
A bathymetric model based on multibeam sonar is so accurate that it is possible to see even small variations in the seabed from year to year. This information could be used to evaluate how much sediment is transported to or from the area either in connection with natural sediment transport or by recovery of raw materials. Bathymetric models based on “paravane diving” cannot be used for this purpose.
Common mussels
Figure A11.5 Distribution of common mussels, paravane dives.
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Figure A11.6. Distribution of common mussels, side-scan sonar.
Investigation of the mussel distribution leads to the following conclusions:
• The “paravane diving” describes the area well; • The sonar survey gives a better delimitation of the areas, but with a poorer cover resolution than the “paravane diving” (Figure A11.6); • The sonar survey depends on diver calibration for interpretation; • The sonar survey is not suited for mussel cover below 20 % of the bottom area.
Eelgrass
Figure A11.7. Distribution of eelgrass, paravane dives.
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Figure A11.8. Distribution of eelgrass, side-scan sonar.
Investigation of the eelgrass distribution leads to the following conclusions:
• The limited spatial distribution of eelgrass in the area made it unsuitable for a good evaluation of the sonar’s potential; • This investigation indicates that an eelgrass cover above 10 % is recognisable on the sonar mosaic (Figure A11.8); • The positioning of the eelgrass is relatively certain, delimitation is expected to be better based on the sonar mosaic, than the paravane dives; • The estimated eelgrass cover is highly uncertain, due to the limited spatial distribution and cover.
Stones
Figure A11.9. Distribution of stones > 20 cm based on paravane dives.
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Figure A11.10. Distribution of stones > 20 cm based on side- scan sonar.
Investigation of the distribution of stones > 20 cm leads to the following conclusions:
• The sonar survey depends on diver calibration; • Separation from common mussels is very difficult; • The sonar survey gives a good delimitation of the area (Figure A11.10); • The sonar survey gives a poor certainty and an inferior possibility to determine cover; • The determination of cover by paravane dives is good; • Paravane dives are more uncertain in delimitation between the transects due to the interpolation.
Technical Comparison
Comparison of the two methods documents that the level of details provided by side-scan sonar are significantly lower than that provided by the observations made by the paravane transects. On the other hand the side- scan interpretation gives, due to the higher coverage of the area, a possibility to delimit large spreads of single elements on the seabed. In most areas, a side-scan sonar survey cannot be used as an alternative to diver observations, but it can be used as a supplement that will increase the quantity of information.
The different methods to evaluate characteristic parametres on the seabed have different applicability. In Table A11.1 an evaluation of the applicability of the different methods is given. The multibeam sonar and side-scan sonar cover approximately 95 % of the investigation area while the sub-bottom profiler retains data from a single line below the ship. On the other hand, the paravane dives cover an area of approximately 6 % of the investigation area.
For comparison, photo-monitoring will typically cover 0.1 % of a similar area on a single day. Furthermore, photo- monitoring will need a secondary interpretation. This interpretation will normally be inferior to the direct observation of the diver due to a poorer resolution in the pictures.
The spatial resolution and certainty of the paravane dives can be improved by adding transects, which might be necessary in areas with a more diverse seabed. Multibeam sonar is accurate regarding bathymetry, while side-scan sonar is better regarding larger stones and might have a potential for registering eelgrass, mussels and large sessile macroalgae.
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Table A11.1. Evaluation of the applicability of the different methods.
Parametres Paravene dives Side-scan sonar Multibeam sonar Sub-bottom profiler Interpretation Depth +++ - ++++ ++ B/G Mussels +++ ++ - - B Eelgrass +++ ++(+) (+) - B Macroalgae +++ (+) - - B Stones > 20 cm +++ ++++ + + B/G Stones < 20 cm +++ - - - B/(G) Soft bottom +++ + - - B/(G) Thickness of - - - +++ G sediment layer
++++ good recognition, good estimation of cover and good delimitation of area; +++ good recognition, good estimation of cover and less good delimitation of area; ++ bad recognition, uncertain estimation of cover and good delimitation of area; + bad recognition, uncertain estimation of cover and uncertain delimitation of area; () has to be verified on a more suited locality; - not investigated/unsuited; B the material is used for biological interpretation; G the material is used for geological interpretation.
Financial estimations
One day of paravane diving can cover an area of approximately 2 km2 with a seabed coverage of 6–10 % depending on the visibility and water depth. No extra cost for transporting diving vessel.
The same area can be covered by a sonar survey in two days, but displacement to and from the survey area should be taken into account. As a consequence a further cost of allowances should be added.
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Table A11.2. Comparison of costs for survey of an area of 2 km2 by 1) side-scan sonar and 2) biological screening in Denmark.
Method Price (all prices in DKK)* Biological screening 40,000 Biological screening incl. photo sampling 50,000 Side-scan sonar survey approx. 130,000 Additional Requirements Diver calibration max. 40,000 Bathymetry by multibeam 20,000 Geology by sub-bottom profiler 25,000 Total sonar survey max. 215,000
* 8.5 DKK equals 1 USD.
The best quality of a biological screening is obtained by the “paravane diving” survey.
The sonar survey has a poorer quality regarding biological conditions, but gives, in correlation with the diver survey, a better information on the spatial distribution of selected parametres.
If bathymetry (model of depths) and/or determination of thickness of sand layers is needed, a “paravane diving” survey of biological parametres can be supplemented with a sonar survey using multibeam sonar for bathymetry and/or sub- bottom profiler for thickness of sand layers.
RECOMMENDATIONS
Biological screening conducted as paravane diving in smaller areas (2–4 km2) with the purpose of determining biological conditions only, is recommended rather than sonar observation due to the higher quality of information, higher resolution and lower price although the sonar survey provides higher coverage of the investigation area.
Furthermore, it is recommended that photo/video is used for visual documentation only, thus not for the actual biological screening.
Larger areas (especially considerably deeper and/or larger areas, i.e., a construction site) can be investigated using a preliminary sonar survey. This survey will form the basis of the determination of the necessary transects and/or spot dives for calibration of sonar mosaic.
In investigations where an accurate bathymetry is required (i.e., measurement of removed quantities, hydrodynamic modelling, etc.) a multibeam sonar survey is recommended.
For areas that need determination of geological conditions, including e.g., the thickness of sand layers, side-scan sonar (for large stones), sub-bottom profiler (for seismic) and multibeam sonar (for bathymetry) should be used. In this way thickness and delimitation of sand layers can be registered.
It should, however, be noticed that efforts are made to improve the results gained by the sonar systems. Thus, it is expected that improvements of the sonar interpretation will lead to better results in the future although the paravane price advantage on biological screening is expected to resist.
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ANNEX 12: APPARENT INCOMPATIBILITY BETWEEN BIOLOGICAL SETTINGS OF WGEXT GUIDELINES AND CURRENT AGGREGATE DREDGING APPLICATIONS IN THE EASTERN ENGLISH CHANNEL
Frédéric COURBET and Michel LEMOINE
IFREMER, Laboratoire Ressources Halieutiques, Station de Port-en-Bessin (Normandie) Av. du Général de Gaulle, 14520 Port-en-Bessin, FRANCE
Within the description of biological settings provided by the WGEXT guidelines on sand and gravel extraction, various kinds of biologically sensitive areas requiring protection against human activities and particularly aggregate extraction are identified.
These areas are spawning grounds with particular regard to benthic spawning species, nursery areas, over-wintering grounds for ovigerous crustaceans and known routes of migration.
Many extraction projects have emerged over recent years in the Eastern Channel offshore waters and scientific advice will have to be provided regarding their compatibility with the biological functions of the affected seabed.
This potential conflict of interests is often illustrated and assessed through cartographic confrontation of scientific knowledge and industrial project outlines.
Unfortunately, this confrontation between thematic maps often underlines several different kinds of difficulties. Taking spawning areas as an example, at present we can observe:
• a large uncertainty of the exact location of the spawning areas and an incapacity to clarify the presence/absence ratio; • the fact that the current offshore applications globally stand upon biologically sensitive areas as spawning grounds; • a practical impossibility to avoid large overlaps between industrial projects and these sensitive areas which potentially cover the largest part of the seabed.
In order to avoid opposition between biologists and others stakeholders it looks as though it will be necessary either to improve knowledge or put scientific certainties into perspective.
As the present situation cannot carry on indefinitely, and as it is difficult to quickly get significant new knowledge about spawning areas and routes of migration, current industrial applications will have to be assessed in terms of acceptable risk considering the various marine resources, sensitive areas and fishing activities.
Maybe the principles of EcoQ and EcoQO can be used in this kind of issue.
(This presentation was supported by many thematic maps indicating known spawning grounds – copies of these may be obtained from the authors)
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ANNEX 13: RECOMMENDATIONS AND PROPOSED TERMS OF REFERENCE FOR WGEXT 2003
The Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem [WGEXT] (Chair: Prof. J. Side, UK) will meet in Oostende, Belgium from 1–5 April 2003 as guests of MUMM and DvZ in order to: a) review data on marine extraction activities, developments in marine resource mapping, information on changes to the legal regime (and associated environmental impact assessment requirements) governing marine aggregate extraction; b) review scientific programmes and research projects relevant to the assessment of environmental effects of the extraction of marine sediments; c) review the template and electronic submission procedures for recording and collating national reports; d) receive feedback on the use of the new ICES Guidelines for the Management of Marine Sediment Extraction, and consider whether further specific guidance is required in special cases of extraction activities where unusual environmental conditions prevail, discussing also any feedback received on observations for procedures dealing with transboundary issues; e) continue work on the planned ICES Cooperative Research Report, and in particular to this end: i) provide a review of the quantity, quality, location and uses of marine sediments extracted annually since 1980; ii) continue to review the application of risk assessment methods as a tool for the management of marine sediment extraction; iii) continue to assess localised impacts from aggregate extraction on fisheries, and the means to adequately protect known areas sensitive for fisheries resources, e.g., herring spawning beds in the vicinity of extraction operations, particularly in the light of methods for determining impacts and the use of risk assessment; iv) review progress made by individual authors in scoping the detail of the content of sections of the report.
WGEXT will report by 22 April 2003 for the attention of the Marine Habitat and Resource Management Committees and ACME and ACE. Priority: Current activities are concerned with developing the understanding necessary to ensure that marine sand and gravel extraction is managed in a sustainable manner, and that any ecosystem (and fishery) effects of this activity are better understood so that mitigative measures can be adopted where appropriate. These activities are considered to have a very high priority.
Scientific Justification: a),b) An increasing number of ICES Member Countries undertake sand and gravel extraction activities and others are looking at the potential for future exploitation. Each year relevant developments under these headings are reviewed and summarised. This provides a useful forum for information exchange and discussion. National reports are submitted electronically prior to the meeting and this year a new electronic reporting format has been tested. National Reports should be submitted, using the new reporting template, no later than 16 March 2003.
c) This request was made by ACME and a reporting format was adopted at WGEXT 2001. It will be tested for electronic data returns in the coming year and reviewed at WGEXT 2003.
d) The new Guidelines (finalised at WGEXT 2002) incorporate both guidance on EIA for aggregate extraction activities and guidance contained in the previous ICES Code of Practice on sand and gravel extraction. WGEXT will monitor whether there are special cases of extraction activity that would not normally be covered by this guidance, and also any responses to its observations on extraction projects with transboundary environmental implications.
e) This work is ongoing and responds in particular to the recommendations contained in previous ICES Cooperative Research Reports (Nos. 183 and
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247). It will also incorporate the most recent work undertaken by WGEXT on risk management and on effects of sediment extraction activities on fisheries, together with the review of all major research projects on the ecosystem effects of sediment extraction activities. This is seen by WGEXT as a major periodic deliverable from its work.
Relation to Strategic Plan The principal focus of WGEXT work is in relation to Objective 2(c), but other terms of reference also relate to Objectives 1(a), 1(c), 1(e), and 4(a).
Resource Requirements: Most countries collect data and information routinely on aggregate extraction activities. The additional work in presenting these data in a standardised form for the new electronic template is considered small, but in the long-term should result in a reduction in effort.
Reviews of research activity are of programmes that are already under way and have resources committed.
Participants: WGEXT is normally attended by 20–25 members and guests.
Secretariat Facilities: WGEXT 2003 will be hosted by MUMM in Belgium.
Financial: No additional financial implications
Linkages to Advisory Committees: ACME
Linkages to other Committees or BEWG, WGMHM Groups:
Linkages to other Organisations: Work is of direct interest to OSPAR and HELCOM.
Cost share ICES 100 %
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