Technical Guidelines For Environmental Dredging Of Contaminated .

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ERDC/EL TR-08-29Technical Guidelines for EnvironmentalDredging of Contaminated SedimentsEnvironmental LaboratoryMichael R. Palermo, Paul R. Schroeder, Trudy J. Estes,and Norman R. FrancinguesApproved for public release; distribution is unlimited.September 2008

ERDC/EL TR-08-29September 2008Technical Guidelines for EnvironmentalDredging of Contaminated SedimentsMichael R. Palermo, Paul R. Schroeder, Trudy J. Estes, and Norman R. FrancinguesEnvironmental LaboratoryU.S. Army Engineer Research and Development Center3909 Halls Ferry RoadVicksburg, MS 39180-6199Final reportApproved for public release; distribution is unlimited.Prepared forU.S. Environmental Protection AgencyOffice of Solid Waste and Emergency ResponseWashington, DC 20314-1000

ERDC/EL TR-08-29Abstract: This report provides technical guidelines for evaluatingenvironmental dredging as a sediment remedy component. This documentsupports the Contaminated Sediment Remediation Guidance forHazardous Waste Sites, released by the U.S. Environmental ProtectionAgency (USEPA) in 2005, by providing detailed information regardingevaluation of environmental dredging as a remedy component. Thisdocument is intended to be applicable to contaminated sediment sitesevaluated under various environmental laws and regulatory programs. Theintended audience for this report includes all stakeholders potentiallyinvolved in evaluating environmental dredging for purposes of a feasibilitystudy, remedial design, and implementation.The scope of this document is limited to the technical aspects of theenvironmental dredging process itself, but it is important thatenvironmental dredging be integrated with other components such astransport, dewatering, treatment, and rehandling and disposal options.This report covers initial evaluation, pertinent site conditions andsediment characteristics, environmental dredging performance standards,equipment capabilities and selection, evaluation of production, duration,and transport, methods for estimating resuspension, residuals and release,control measures, operating methods and strategies, and monitoring.DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes.Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products.All product names and trademarks cited are the property of their respective owners. The findings of this report are not tobe construed as an official Department of the Army position unless so designated by other authorized documents.DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR.ii

ERDC/EL TR-08-29ContentsFigures and Tables.viiiPreface.xUnit Conversion Factors. xii1Introduction. 11.1 Background . 11.2. Purpose, scope, and applicability . 21.3. Environmental dredging objectives and processes . 31.4. Evaluation sequence for environmental dredging . 52Initial Evaluation.172.1. Conditions conducive to dredging. 172.2. Potential advantages and limitations of dredging .182.3. Environmental dredging as a component of a sediment removal remedy.202.4. Evaluation of project requirements and constraints .222.5. Preliminary evaluation of dredging feasibility .232.6. Pilot studies . 243Evaluating Site Conditions and Sediment Characteristics .263.1. Identifying and filling data gaps. 273.1.1. General considerations for site and sediment characterization . 273.1.2. Conceptual site model . 293.2. Site conditions .303.2.1. Project setting and sources of contamination. 313.2.2. Positioning and survey control . 313.2.3. Access to the water body. 323.2.4. Waterway uses and infrastructure . 323.2.5. Siting for transport, rehandling, treatment, and disposal. 343.2.6. Water depths and bathymetry . 353.2.7. Hydrodynamics. 363.2.8. Elevation and nature of bedrock or hard bottom . 373.2.9. Shoreline stability. 383.2.10. Presence and extent of debris . 393.2.11. Habitat considerations and seasonal dredging restrictions. 423.2.12. Winter icing conditions . 433.2.13. Ambient water and air quality . 433.3. Sediment characterization .443.3.1. Sampling plans and data quality. 443.3.2. Positioning and vertical survey control for sampling. 463.3.3. Sediment sampling equipment and techniques. 473.3.4. Core compression, segmentation, and compositing. 48iii

ERDC/EL TR-08-293.3.5. Sediment physical properties . 503.3.6. Sediment contaminant concentrations . 523.4. Removal requirements .533.4.1. Debris removal . 533.4.2. Dredgeability. 553.4.3. Volume to be dredged. 564Environmental Dredging Performance Standards .584.1. Goals, objectives, and performance standards .584.2 Performance standards related to production and implementation time. 614.2.1. Time of project completion . 614.2.2. Limits on solids content and volume throughput . 624.3. Performance standards related to resuspension and release .634.3.1. Sediment resuspension . 634.3.2. Water quality standards. 634.3.3. Air quality standards . 644.4. Performance standards related to dredging effectiveness.655Equipment Capabilities and Selection.665.1. Dredging equipment types and methods .665.1.1. Hydraulic dredging . 685.1.2. Mechanical dredging . 805.1.3. Equipment combinations and hybrid approaches . 855.2. Considerations for equipment selection .855.3. Equipment capabilities and selection factors. 875.3.1. Production rates . 935.3.2. Percent solids by weight (solids concentration) . 955.3.3. Vertical operating accuracy . 965.3.4. Horizontal operating accuracy.1015.3.5. Maximum dredging depth.1045.3.6. Minimum dredging depth .1045.3.7. Sediment resuspension control.1055.3.8. Contaminant release control .1075.3.9. Residual sediment control and cleanup levels.1125.3.10. Transport by pipeline .1145.3.11. Transport by barge.1165.3.12. Positioning control .1175.3.13. Maneuverability.1185.3.14. Portability/Access .1195.3.15. Availability .1205.3.16. Debris/Loose Rock/Vegetation.1205.3.17. Hardpan/Rock Bottom .1215.3.18. Sloping bottom .1235.3.19. Flexibility for varying conditions .1245.3.20. Thin lift/residuals removal .126iv

ERDC/EL TR-08-295.4. Summary of considerations in selection of equipment.1275.5. Case studies .1286Evaluating Production, Project Duration, and Transport . 1316.1. General considerations for evaluation of production .1316.1.1. Approach.1316.1.2. Factors affecting production for environmental dredging .1356.2. Selection of dredge size(s) for evaluation .1376.2.1. Dredge size related to transport, rehandling, and disposal constraints.1386.2.2. Dredge size as related to cut thickness .1396.2.3. Dredge size related to site characteristics .1406.2.4. Dredge size related to dredgeability .1406.3. Estimate of operating production rates.1416.3.1. Methods for estimating operating production rate .1436.3.2. Mechanical production rates based on operating parameters .1456.3.3. Hydraulic production rates based on operating parameters.1466.4. Estimate of sustained production rate .1496.5. Project duration and needed dredge sizes and number of dredges .1516.6. Considerations for sediment transportation.1517Methods for Estimating Resuspension, Residuals, and Release . 1567.1. Sediment resuspension .1587.1.1. Characteristic resuspension factors .1597.1.2. Adjustments to characteristic resuspension factors.1617.1.3. Nakai TGU method .1627.1.4. Collins (1995) resuspension correlations for open clamshells .1637.1.5. Hayes et al. (2000) cutterhead correlation method .1657.1.6. USACE DREDGE model .1677.1.7. EPA ARCS guidance .1687.1.8. Fate and transport models .1687.1.9. Resuspension controls.1697.2. Residuals .1707.2.1. Residuals characteristics.1727.2.2. Factors affecting dredging residuals.1757.2.3. Predicting dredging residuals .1777.2.4. Example calculation of generated residuals .1787.3. Contaminant release .1807.3.1. Particulate contaminant releases from resuspension .1827.3.2. Dissolved contaminant releases from resuspension .1847.3.3. Dissolved contaminant releases from residuals .1887.3.4. DRET test .1897.3.5. Contaminant volatilization to air .1917.3.6. Volatilization flux test .1927.3.7. Fate and transport models .1927.3.8. Release controls.1937.4. Summary of predictive methods for resuspension, residuals, and release .194v

ERDC/EL TR-08-298Control Measures. 1958.1. Control measures for sediment resuspension .1958.1.1. Operational control measures for sediment resuspension .1968.1.2. Engineered control measures for resuspension .1978.1.3. Silt curtains/screens.1998.1.4. Sheet-pile enclosures and other structural barriers .2048.2. Control measures for contaminant release .2068.2.1. Control of NAPL releases and floatable materials .2068.2.2. Control of particulate contaminant releases .2068.2.3. Control of dissolved contaminant releases .2078.2.4. Control of volatile emissions.2078.3. Control of residuals .2088.3.1. Operational controls for residuals.2098.3.2. Post-dredging control measures for residuals.2108.4. Summary.2138.5. Case studies .2138.5.1. Examples of structural controls.2148.5.2. Examples of operational controls.2158.5.3. Monitoring effectiveness of controls.2168.5.4. Reported costs and production rates .2169Operating Methods and Strategies. 2199.1. Management units and dredging prisms .2199.1.1. Sediment management unit.2199.1.2. Neat line prism and neat line volume .2209.1.3. Dredging prism or dredging prism volume .2219.1.4. Dredging management unit.2249.1.5. Compliance demonstration areas .2279.2. Dredge cuts and cleanup passes .2279.2.1. Cuts .2279.2.2. Overdredging .2309.2.3. Cleanup passes .2319.3. Sequence of work .2339.4. Operations plan .23510 Monitoring. 23610.1. General monitoring considerations .23610.1.1. Monitoring framework and the six-step process.23610.1.2. Short-term versus long-term monitoring.23710.1.3. Monitoring objectives and elements for environmental dredging .23810.2. Monitoring for removal accuracy, production, and times of completion .23910.3. Monitoring for sediment resuspension and water column contaminantrelease .24010.3.1. Points of compliance and sampling locations.24010.3.2. Total suspended solids versus turbidity .24210.3.3. Plume definition .242vi

ERDC/EL TR-08-2910.3.4. Water column sampling.24310.4. Monitoring for volatile contaminant release .24310.5. Monitoring for dredging effectiveness.24410.5.1. Lag times and points of compliance.24510.5.2. Thickness of residuals .24610.5.3. Sampling for residuals.24710.5.4. Engineering/operational evaluation of post-dredging conditions.24910.6. Monitoring plans.25010.7. Management actions.25110.7.1. Management actions for production .25110.7.2. Management actions for resuspension and contaminant release.25210.7.3. Management actions for residuals .25210.8. Monitoring for adaptive management.25311 Summary, Integration, and Conclusions . 25511.1 Summary and integration .25511.2. Conclusions .255References. 259Bibliography.273Appendix A: Dredging Elutriate Test Procedure.278Introduction .278Dredging elutriate tests for water quality evaluation .278Apparatus .279Dredging elutriate test procedure .280Chemical analyses .283Released contaminant concentrations.283Dredging elutriate for water column toxicity .286Elutriate apparatus .286Dredging elutriate procedure .287Dredging elutriate toxicity evaluation .287References.288Report Documentation Pagevii

ERDC/EL TR-08-29Figures and TablesFiguresFigure 1. Conceptual illustration of environmental dredging and processes. 4Figure 2. Flowchart illustrating environmental evaluation/design sequence. . 7Figure 3. Example flow diagram of the possible steps in a dredging or excavationalternative. 22Figure 4. Example of an acoustic survey track. 36Figure 5. Example of a sub-bottom profile image. (Graphics courtesy of CR Environmentaland Parsons). . 38Figure 6. Example guideline for shoreline structure stability (Otten 2006). 39Figure 7. Example of side-scan sonar (a) mosaic, (b) side-scan image showing debris atbase of a mooring dolphin, (c) side-scan image showing unidentified cylindricalobject (13 ft long). (Graphics courtesy of CR Environmental and Parsons). 41Figure 8. Examples of magnetic survey results (a) magnetic contours and (b) magneticanomalies. (Graphics courtesy of CR Environmental and Parsons). . 42Figure 9. Photos of sediment sampling equipment. 48Figure 10. Debris fouling of cutterhead by cables. . 54Figure 11. Photos of basic dredging equipment. . 69Figure 12. Photos of specialty dredging equipment. . 70Figure 13. Components of a hydraulic dredge. . 72Figure 14. Vic Vac hydraulic dredgehead for residuals. . 77Figure 15. Mouth of suction pipe and conventional basket cutterhead. 78Figure 16. Spillage layer from conventional hydraulic cutterhead dredge. . 79Figure 17. Components of a mechanical bucket dredge. 81Figure 18. Components of a wire-supported clamshell dredge. . 82Figure 19. Cross section showing required dredging elevation vs. target dredging el

ERDC/EL TR-08-29 ii Abstract: This report provides technical guidelines for evaluating environmental dredging as a sediment remedy component. This document supports the Contaminated Sediment Remediation Guidance for Hazardous Waste Sites, released by the U.S. Environmental Protection Agency (USEPA) in 2005, by providing detailed information regarding