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London Convention Guidelines for Assessment of Dredged Material PIANC-Dredged Material Management Guidance Documents

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Presentation on theme: "London Convention Guidelines for Assessment of Dredged Material PIANC-Dredged Material Management Guidance Documents"— Presentation transcript:

1 London Convention Guidelines for Assessment of Dredged Material PIANC-Dredged Material Management Guidance Documents

2 Specific Guidelines for Assessment of Dredged Material Introduction Dredging is essential to maintain navigation in ports, harbours, marinas and inland waterways; for the development of port facilities; for flooding mitigation; and for removal of sediments from structures, basins and water intakes. Dredged material worldwide is, by nature, similar to undisturbed sediments in inland and coastal waters. A smaller proportion of dredged material, however, is contaminated by human activity.

3 Evaluation of Need for Dredging and Disposal CAPITAL DREDGING - for navigation, to enlarge or deepen existing channel and port areas or to create new ones MAINTENANCE DREDGING - to ensure that channels, berths or construction works, etc., are maintained at their designed dimensions; and CLEAN UP DREDGING - deliberate removal of contaminated material for human health and environmental protection purposes.

4 The schematic provides a clear indication of the stages in the application of this guidance where important decisions should be made. Components are: 1. Dredged material characterization 2. Waste prevention audit and evaluation of disposal options 3. Is material acceptable 4. Identify and characterize dump-site 5. Determine potential impacts and prepare impact hypothesis(es) 6. Issue permit 7. Implement project and monitor compliance 8. Field monitoring and assessment (monitoring)

5 Dredged Material Assessment Framework DETERMINE POTENTIAL IMPACTS AND PREPARE IMPACT HYPOTHES(I/E)S IDENTIFY AND CHARACTERIZE DISPOSAL SITE IS MATERIAL ACCEPTABLE? BENEFICIAL USE POSSIBLE? FIELD MONITORING & ASSESSMENT IMPLEMENT PROJECT & MONITOR COMPLIANCE DREDGED MATERIAL CHARACTERIZATION ISSUE PERMIT? CAN MATERIAL BE MADE ACCEPTABLE? SOURCE CONTROL OTHER BENEFICIAL USE NEED FOR DREDGING NO YES Representation of the Jurisdictional Boundary of the Convention YES

6 DREDGED MATERIAL CHARACTERIZATION SOURCE CONTROL NEED FOR DREDGING

7 IS MATERIAL ACCEPTABLE? BENEFICIAL USE POSSIBLE? CAN MATERIAL BE MADE ACCEPTABLE? OTHER BENEFICIAL USE NO YES NO YES NO YES

8 IDENTIFY AND CHARACTERIZE DISPOSAL SITE DETERMINE POTENTIAL IMPACTS AND PREPARE IMPACT HYPOTHES(UE)S NO

9 ISSUE PERMIT? NO YES

10 IMPLEMENT PROJECT & MONITOR COMPLIANCE FIELD MONITORING & ASSESSMENT YES

11 For dredged material, the goal of waste management should be to identify and control the sources of contamination. SOURCE CONTROL STRATEGY 1. The continuing need for dredging; 2. The hazards posed by contaminants and the relative contributions of the individual sources to these hazards; 3. Existing source control programmes and other regulations or legal requirements; 4. Technical and economic feasibility; 5. The evaluation of the effectiveness of measures taken; and 6. Consequences of not implementing contaminant reduction. Waste Prevention Audit

12 Reduce or control impacts to a level that will not constitute unacceptable risks Treatment Disposal management techniques Methods of containing dredged material in a stable manner The practical availability of other means of disposal should be considered in the light of a comparative risk assessment involving both dumping and the alternatives Management Options

13 Physical characterization The basic physical characteristics required are the amount of material Exemptions from detailed characterization Dredged material is excavated from a site away from existing and historical sources of appreciable pollution, so as to provide reasonable assurance that the dredged material has not been contaminated, or dredged material is composed predominantly of sand, gravel and/or rock, or dredged material is composed of previously undisturbed geological materials. Dredged Material Characterization

14 Available information Geochemical characteristic Contaminant routes /sources Chemical Characterization

15 Biological tests should incorporate: Acute toxicity Chronic toxicity and sub-lethal effects The potential for bioaccumulation The potential for tainting at and in the vicinity of the disposal site. Biological Characterization

16 Chemical and/or biological screening resulting in: - Wastes containing specified substances, or causing biological responses, exceeding the relevant upper level shall not be dumped, unless made acceptable. - Wastes which contain specified substances, or which cause biological responses, below the relevant lower levels should be considered to be of little environmental concern. - Wastes, which contain specified substances, or which cause biological responses, below the upper level but above the lower level require more detailed assessment before their suitability for dumping can be determined. Action List

17 Site Selection Considerations: Physical, chemical and biological characteristics of the water-column and the seabed Location of amenities, values and other uses of the sea in the area under consideration Assessment of the constituent fluxes associated with dumping in relation to existing fluxes of substances in the marine environment Economic and operational feasibility Dump-Site Selection

18 The shoreline and bathing beaches Areas of beauty or significant cultural or historical importance Areas of special scientific or biological importance, such as sanctuaries Fishing areas Spawning, nursery and recruitment areas Migration routes Seasonal and critical habitats Shipping lanes Military exclusion zones Engineering uses of the seafloor Important Amenities, Biological Features and Uses of the Sea

19 Size of the dump-site Site capacity Evaluation of potential impacts Contaminant mobility Site Selection Consideration

20 Impact hypothesis Integrate waste characteristics / site information Comprehensive assessment Emphasis on biological effects / habitat modification Cumulative impacts Assessment of Potential Effects

21 Compliance monitoring, Field monitoring Modify or terminate the field-monitoring programme Modify or revoke the permit Redefine or close the dump-site Modify the assessment basis Monitoring

22 The types, amounts and sources of materials to be dumped The location of the dump-site(s) The method of dumping Monitoring and reporting requirements Permit and Permit Conditions

23 Assessment framework (LC) Material characterization Sustainable relocation International Navigation Association PIANC Dredged Material Management Guide (Supplement to Bulletin no. 96, 1987

24 Management options Contamination source control Management strategy Relevant background literature

25 Aquatic (LC guides) Land-based confined disposal - Contaminant release mechanisms - Processes - Pathways - Isolation - Surplus water treatment Disposal

26 Implementation guidelines Monitoring (physical and environmental) Evaluation Optimization Confined Disposal Site Management

27 Pretreatment Biological Chemical Thermal Immobilization Treatment

28 Beneficial or adverse Long- or short-term Direct or indirect Reversible or irreversible Local or strategic Independent or cumulative Impact Assessment

29 Specification of baseline conditions Port operational monitoring Monitoring

30 International Navigation Association PIANC Management of Aquatic Disposal of Dredged Material (Working Group )

31 1. Introduction 2. Management framework 3. Dredged material and site characterization Outline Survey and sampling methods Dredged material characterization - Physical - Chemical - Ecotoxicological - Biological

32 Outline (cont.) Characterization of disposal site - Physical - Chemical - Biological - Functional uses of receiving area

33 Outline (cont.) Effects of disposal - Physical processes - Physical effects on ecology - Chemical and ecotoxicological - Functional uses / amenities

34 Outline (cont.) International, regional and National environmental controls - General approaches - Marine and estuarine disposal - Inland waterways disposal

35 Planning and engineering for aquatic disposal - Regulatory decision framework - Technical decision framework - Project decision framework

36 Operational aspects of aquatic disposal - Operations plan - Monitoring requirements

37 References Annexes - Description of physical properties of dredged material - Metals in sediments - List of international agreements, protocols and guidelines - Beneficial uses of dredged material in the aquatic environment - Mitigation measures - Consideration in design of monitoring plans

38 Managing Contaminated Dredged Material Defining CDM Risks Chemical characteristics and sources

39 Identifying, Assessing, and Selecting Options Planning CDM projects State-of-the-art technologies PIANC technical position Documenting results with case studies

40 Dredging: The Environmental Facts Where to Find What You Need to Know Dredging a vital process Dredging for sustainable development Dredging must be safe and sound

41 Sources of Information CEDA IADC WODA PIANC IAPH WEDA EDA

42 CEDA IAPH WEDA EDA


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