Presentation on theme: "London Convention Guidelines for Assessment of Dredged Material"— Presentation transcript:
1London Convention Guidelines for Assessment of Dredged Material PIANC-Dredged MaterialManagement Guidance Documents
2Specific Guidelines for Assessment of Dredged Material IntroductionDredging 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.
3Evaluation of Need for Dredging and Disposal CAPITAL DREDGING - for navigation, to enlarge or deepen existing channel and port areas or to create new onesMAINTENANCE DREDGING - to ensure that channels, berths or construction works, etc., are maintained at their designed dimensions; andCLEAN UP DREDGING - deliberate removal of contaminated material for human health and environmental protection purposes.
4The 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 characterization2. Waste prevention audit and evaluation of disposal options3. Is material acceptable4. Identify and characterize dump-site5. Determine potential impacts and prepare impact hypothesis(es)6. Issue permit7. Implement project and monitor compliance8. Field monitoring and assessment (monitoring)
5Dredged Material Assessment Framework SOURCECONTROLOTHERNOYESCAN MATERIALACCEPTABLE?BE MADENONORepresentation of the Jurisdictional Boundary of the ConventionDredged Material Assessment FrameworkNOYESYESIMPLEMENT PROJECT &MONITOR COMPLIANCENEED FOR DREDGINGDREDGED MATERIALCHARACTERIZATIONIDENTIFY AND CHARACTERIZEDISPOSAL SITEIS MATERIALACCEPTABLE?DETERMINE POTENTIALIMPACTS AND PREPAREIMPACT HYPOTHES(I/E)SBENEFICIAL USEPOSSIBLE?ISSUE PERMIT?FIELD MONITORING& ASSESSMENTYESBENEFICIALUSE
6NEED FOR DREDGINGDREDGED MATERIALCHARACTERIZATIONSOURCECONTROL
7CAN MATERIAL IS MATERIAL OTHER BENEFICIAL USE BE MADE ACCEPTABLE? NONOOTHERYESYESYESBENEFICIAL USEPOSSIBLE?BENEFICIALUSENO
8IDENTIFY AND CHARACTERIZE DISPOSAL SITE NOIDENTIFY AND CHARACTERIZE DISPOSAL SITEDETERMINE POTENTIAL IMPACTS AND PREPARE IMPACT HYPOTHES(UE)S
11Waste Prevention Audit For dredged material, the goal of waste management should be to identify and control the sources of contamination.SOURCE CONTROL STRATEGY1. 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; and6. Consequences of not implementing contaminant reduction.
12Management OptionsReduce or control impacts to a level that will not constitute unacceptable risksTreatmentDisposal management techniquesMethods of containing dredged material in a stable mannerThe practical availability of other means of disposal should be considered in the light of a comparative risk assessment involving both dumping and the alternatives
13Dredged Material Characterization Physical characterizationThe basic physical characteristics required are the amount of materialExemptions from detailed characterizationDredged material is excavated from a site away from existing and historical sources of appreciable pollution, so as to provide reasonable assurance that thedredged material has not been contaminated, ordredged material is composed predominantly of sand, gravel and/or rock, ordredged material is composed of previously undisturbed geological materials.
14Chemical Characterization Available informationGeochemical characteristicContaminant routes /sources
15Biological Characterization Biological tests should incorporate:Acute toxicityChronic toxicity and sub-lethal effectsThe potential for bioaccumulationThe potential for taintingat and in the vicinity of the disposal site.
16Action List 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.
17Dump-Site Selection Site Selection Considerations: Physical, chemical and biological characteristics of the water-column and the seabedLocation of amenities, values and other uses of the sea in the area under considerationAssessment of the constituent fluxes associated with dumping in relation to existing fluxes of substances in the marine environmentEconomic and operational feasibility
18Important Amenities, Biological Features and Uses of the Sea The shoreline and bathing beachesAreas of beauty or significant cultural or historical importanceAreas of special scientific or biological importance, such as sanctuariesFishing areasSpawning, nursery and recruitment areasMigration routesSeasonal and critical habitatsShipping lanesMilitary exclusion zonesEngineering uses of the seafloor
19Site Selection Consideration Size of the dump-siteSite capacityEvaluation of potential impactsContaminant mobility
20Assessment of Potential Effects Impact hypothesisIntegrate waste characteristics / site informationComprehensive assessmentEmphasis on biological effects / habitat modificationCumulative impacts
21Monitoring Compliance monitoring, Field monitoring Modify or terminate the field-monitoring programmeModify or revoke the permitRedefine or close the dump-siteModify the assessment basis
22Permit and Permit Conditions The types, amounts and sources of materials to be dumpedThe location of the dump-site(s)The method of dumpingMonitoring and reporting requirements
23International Navigation Association PIANC Dredged Material Management Guide(Supplement to Bulletin no. 96, 1987Assessment framework (LC)Material characterizationSustainable relocation
24Contamination source control Management strategy Management optionsContamination source controlManagement strategyRelevant background literature
28Impact Assessment Long- or short-term Direct or indirect Beneficial or adverseLong- or short-termDirect or indirectReversible or irreversibleLocal or strategicIndependent or cumulative
29Monitoring Port operational monitoring Specification of baseline conditionsPort operational monitoring
30International Navigation Disposal of Dredged Material AssociationPIANCManagement of AquaticDisposal of Dredged Material(Working Group )
31Outline 2. Management framework 1. Introduction2. Management framework3. Dredged material and site characterizationSurvey and sampling methodsDredged material characterization- Physical- Chemical- Ecotoxicological- Biological
32Outline (cont.) Characterization of disposal site - Physical - Chemical- Biological- Functional uses of receiving area
33Outline (cont.) Effects of disposal - Physical processes - Physical effects on ecology- Chemical and ecotoxicological- Functional uses / amenities
34Outline (cont.)International, regional and National environmental controls- General approaches- Marine and estuarine disposal- Inland waterways disposal
35Planning and engineering for aquatic disposal - Regulatory decision framework- Technical decision framework- Project decision framework
36Operational aspects of aquatic disposal - Operations plan- Monitoring requirements
37- Description of physical properties of dredged material ReferencesAnnexes- 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
38Managing Contaminated Dredged MaterialDefining CDMRisksChemical characteristics and sources
39Identifying, Assessing, and Selecting OptionsPlanning CDM projectsState-of-the-art technologiesPIANC technical positionDocumenting results with case studies
40The Environmental Facts Where to Find What You Need to Know Dredging:The Environmental FactsWhere to Find What You Need to KnowDredging a vital processDredging for sustainable developmentDredging must be safe and sound
41Sources of Information CEDAIADCWODAPIANCIAPHWEDAEDA