R EPORT Preliminary Design Report Hudson River PCBs Superfund Site General Electric Company Albany, New York April 2004 Table of Contents Section 1. Introduction ...............................................................................................................1-1 1.1 Project Setting .................................................................................................................1-1 1.2 Remedial Action Summary .............................................................................................. 1-2 1.3 Remedial Design Objectives ........................................................................................... 1-4 1.4 Design Support Activities................................................................................................. 1-6 1.5 Preliminary Design Report Organization ......................................................................... 1-6 Section 2. Overview of the Remedial Design Process.............................................................2-1 2.1 Project Constraints .......................................................................................................... 2-2 2.1.1 Engineering Performance Standards ................................................................. 2-3 2.1.2 Quality of Life Performance Standards .............................................................. 2-3 2.1.3 Other USEPA Requirements and Limitations..................................................... 2-4 2.1.4 Logistical and Physical Constraints.................................................................... 2-4 2.1.5 Other Considerations Resulting from Scale of the Project................................. 2-5 2.2 Design Approach ............................................................................................................. 2-6 2.3 Design Integration and Optimization Process ................................................................. 2-8 2.4 Remedial Design Schedule ............................................................................................. 2-9 Section 3. Site Characteristics...................................................................................................3-1 3.1 Upland Characteristics .................................................................................................... 3-1 3.1.1 Shoreline Characteristics.................................................................................... 3-2 3.1.1.1 Shoreline Physical Characteristics ..................................................... 3-2 3.1.1.2 Shoreline Topography......................................................................... 3-2 3.1.1.3 Shoreline Structures ........................................................................... 3-3 3.1.2 Land-Based Transportation Characteristics ....................................................... 3-3 3.1.2.1 Roadways ........................................................................................... 3-3 3.1.2.2 Railroads............................................................................................. 3-4 3.1.3 Property Ownership............................................................................................ 3-5 3.2 Hydraulic Characteristics................................................................................................. 3-5 3.2.1 River Flow........................................................................................................... 3-5 3.2.2 Bathymetry.......................................................................................................... 3-7 3.2.3 Navigation Channel ............................................................................................ 3-8 3.2.4 Locks, Dams, and Bridges.................................................................................. 3-9 3.2.5 In-River Characteristics .................................................................................... 3-10 3.3 Dredge Areas................................................................................................................. 3-11 3.4 Sediment Characteristics............................................................................................... 3-12 3.4.1 Sediment PCB Characteristics ......................................................................... 3-12 3.4.2 Sediment Physical Characteristics ................................................................... 3-12 3.4.3 Sub-Bottom Characteristics.............................................................................. 3-13 3.5 Habitats.......................................................................................................................... 3-14 3.6 Cultural and Archaeological Features ........................................................................... 3-15 3.7 Climatological Factors ................................................................................................... 3-16 Section 4. General Design Considerations...............................................................................4-1 4.1 Engineering Performance Standards .............................................................................. 4-1 BLASLAND, BOUCK & LEE, INC. engineers & scientists 1 4.1.1 Dredging Resuspension ..................................................................................... 4-2 4.1.2 Dredging Residuals ............................................................................................ 4-3 4.1.3 Dredging Productivity ......................................................................................... 4-5 4.2 Quality of Life Performance Standards ........................................................................... 4-6 4.3 Other Limitations on Releases of Constituents ............................................................... 4-6 4.4 Availability of Equipment and Material ............................................................................ 4-7 4.4.1 Contractor-Supplied Equipment ......................................................................... 4-7 4.4.2 Materials and Supplies ....................................................................................... 4-7 4.5 Transportation Issues ...................................................................................................... 4-7 4.5.1 In-River Transportation Considerations.............................................................. 4-9 4.5.1.1 Canal Logistics.................................................................................... 4-9 4.5.1.2 Construction Vessel Considerations................................................. 4-11 4.5.2 Land Transportation Considerations ................................................................ 4-12 4.6 River Access Needs ...................................................................................................... 4-12 4.6.1 Processing Facility Locations ........................................................................... 4-13 4.6.2 Land-Locked Area Needs................................................................................. 4-14 4.6.3 Other Access Needs......................................................................................... 4-15 4.7 Construction/Operations Limitations.............................................................................. 4-15 4.7.1 General Limitations on Period of Construction/Operations .............................. 4-15 4.7.2 River-Flow Conditions ...................................................................................... 4-16 4.7.3 Worker Health and Safety ................................................................................ 4-16 4.8 State of the Practice for Environmental Dredging ......................................................... 4-16 Section 5. Dredging Design........................................................................................................5-1 5.1 Basis of Design................................................................................................................ 5-1 5.1.1 Project Requirements ......................................................................................... 5-2 5.1.2 Key Process Variables ....................................................................................... 5-3 5.1.3 Design Assumptions........................................................................................... 5-6 5.2 Design Approach ............................................................................................................. 5-8 5.3 Preliminary Evaluation of Dredge Equipment.................................................................. 5-8 5.3.1 Mechanical Dredges......................................................................................... 5-10 5.3.1.1 Conventional Clamshell Dredge ....................................................... 5-10 5.3.1.2 Environmental Clamshell/ Wire Supported Dredge .......................... 5-11 5.3.1.3 Articulated Mechanical Dredge......................................................... 5-13 5.3.1.4 Amphibious Dredges......................................................................... 5-14 5.3.1.5 Excavation in the Dry........................................................................ 5-15 5.3.2 Hydraulic Dredges ............................................................................................ 5-15 5.3.2.1 Plain Suction Dredge ........................................................................ 5-16