TECHNICAL GUIDELINES FOR ENVIRONMENTAL …

1 ERDC/EL TR-08-29 TECHNICAL GUIDELINES for ENVIRONMENTAL Dredging of Contaminated Sediments Michael R. Palermo, Paul R. Schroeder, Trudy J. Estes, and Norman R. Francingues September 2008 ENVIRONMENTAL Laboratory Approved for public release; distribution is unlimited. ERDC/EL TR-08-29 September 2008 TECHNICAL GUIDELINES for ENVIRONMENTAL Dredging of Contaminated Sediments Michael R. Palermo, Paul R. Schroeder, Trudy J. Estes, and Norman R. Francingues ENVIRONMENTAL Laboratory Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199 Final report Approved for public release; distribution is unlimited.

2 Prepared for ENVIRONMENTAL Protection Agency Office of Solid Waste and Emergency Response Washington, DC 20314-1000 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 ENVIRONMENTAL Protection Agency (USEPA) in 2005, by providing detailed information regarding evaluation of ENVIRONMENTAL dredging as a remedy component. This document is intended to be applicable to contaminated sediment sites evaluated under various ENVIRONMENTAL laws and regulatory programs. The intended audience for this report includes all stakeholders potentially involved in evaluating ENVIRONMENTAL dredging for purposes of a feasibility study, remedial design, and implementation.

3 The scope of this document is limited to the TECHNICAL aspects of the ENVIRONMENTAL dredging process itself, but it is important that ENVIRONMENTAL dredging be integrated with other components such as transport, dewatering, treatment, and rehandling and disposal options. This report covers initial evaluation, pertinent site conditions and sediment 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.

4 All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be 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. ERDC/EL TR-08-29 iii Contents Figures and Tables ..viii Preface ..x Unit Conversion xii 1 1 Background .. 1 Purpose, scope, and applicability .. 2 ENVIRONMENTAL dredging objectives and processes .. 3 Evaluation sequence for ENVIRONMENTAL dredging .. 5 2 Initial 17 Conditions conducive to 17 Potential advantages and limitations of dredging .. 18 ENVIRONMENTAL dredging as a component of a sediment removal 20 Evaluation of project requirements and constraints .. 22 Preliminary evaluation of dredging feasibility.

5 23 Pilot studies .. 24 3 Evaluating Site Conditions and sediment Characteristics ..26 Identifying and filling data gaps .. 27 General considerations for site and sediment characterization .. 27 Conceptual site model ..29 Site conditions .. 30 Project setting and sources of 31 Positioning and survey control .. 31 Access to the water body ..32 Waterway uses and infrastructure .. 32 Siting for transport, rehandling, treatment, and 34 Water depths and bathymetry .. 35 Hydrodynamics .. 36 Elevation and nature of bedrock or hard bottom .. 37 Shoreline 38 Presence and extent of debris .. 39 Habitat considerations and seasonal dredging 42 Winter icing conditions ..43 Ambient water and air quality .. 43 sediment characterization .. 44 Sampling plans and data 44 Positioning and vertical survey control for 46 sediment sampling equipment and 47 Core compression, segmentation, and 48 ERDC/EL TR-08-29 iv sediment physical properties.

6 50 sediment contaminant concentrations .. 52 Removal requirements .. 53 Debris removal .. 53 55 Volume to be dredged ..56 4 ENVIRONMENTAL Dredging Performance Standards ..58 Goals, objectives, and performance standards .. 58 Performance standards related to production and implementation 61 Time of project completion .. 61 Limits on solids content and volume throughput .. 62 Performance standards related to resuspension and release .. 63 sediment resuspension .. 63 Water quality Air quality standards .. 64 Performance standards related to dredging effectiveness .. 65 5 Equipment Capabilities and Dredging equipment types and methods .. 66 Hydraulic dredging .. 68 Mechanical dredging ..80 Equipment combinations and hybrid approaches .. 85 Considerations for equipment selection .. 85 Equipment capabilities and selection 87 Production rates.

7 93 Percent solids by weight (solids concentration) .. 95 Vertical operating accuracy .. 96 Horizontal operating Maximum dredging Minimum dredging depth ..104 sediment resuspension Contaminant release control ..107 Residual sediment control and cleanup Transport by pipeline ..114 Transport by Positioning control ..117 Availability ..120 Debris/Loose Hardpan/Rock Bottom ..121 Sloping bottom ..123 Flexibility for varying Thin lift/residuals removal ..126 ERDC/EL TR-08-29 v Summary of considerations in selection of Case studies ..128 6 Evaluating Production, Project Duration, and Transport .. 131 General considerations for evaluation of production ..131 Factors affecting production for ENVIRONMENTAL dredging ..135 Selection of dredge size(s) for evaluation.

8 137 Dredge size related to transport, rehandling, and disposal constraints ..138 Dredge size as related to cut thickness ..139 Dredge size related to site characteristics ..140 Dredge size related to dredgeability ..140 Estimate of operating production 141 Methods for estimating operating production rate ..143 Mechanical production rates based on operating parameters ..145 Hydraulic production rates based on operating Estimate of sustained production rate ..149 Project duration and needed dredge sizes and number of dredges ..151 Considerations for sediment transportation ..151 7 Methods for Estimating Resuspension, Residuals, and Release .. 156 sediment resuspension ..158 Characteristic resuspension factors ..159 Adjustments to characteristic resuspension Nakai TGU method ..162 Collins (1995) resuspension correlations for open Hayes et al.

9 (2000) cutterhead correlation method ..165 USACE DREDGE model ..167 EPA ARCS guidance ..168 Fate and transport models ..168 Resuspension Residuals ..170 Residuals Factors affecting dredging Predicting dredging residuals ..177 Example calculation of generated residuals ..178 Contaminant release ..180 Particulate contaminant releases from Dissolved contaminant releases from resuspension ..184 Dissolved contaminant releases from residuals ..188 DRET test ..189 Contaminant volatilization to air ..191 Volatilization flux test ..192 Fate and transport models ..192 Release Summary of predictive methods for resuspension, residuals, and release ..194 ERDC/EL TR-08-29 vi 8 Control Measures .. 195 Control measures for sediment resuspension ..195 Operational control measures for sediment resuspension.

10 196 Engineered control measures for resuspension ..197 Silt Sheet-pile enclosures and other structural barriers ..204 Control measures for contaminant release ..206 Control of NAPL releases and floatable materials ..206 Control of particulate contaminant releases ..206 Control of dissolved contaminant releases ..207 Control of volatile Control of residuals ..208 Operational controls for residuals ..209 Post-dredging control measures for Summary ..213 Case studies ..213 Examples of structural Examples of operational Monitoring effectiveness of Reported costs and production 9 Operating Methods and Strategies .. 219 Management units and dredging prisms ..219 sediment management unit ..219 Neat line prism and neat line volume ..220 Dredging prism or dredging prism volume.