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Proceedings, WEDA XXXII Technical Conference & TAMU 43 Dredging Seminar

HUDSON RIVER DREDGING DESIGN – APPLICATION OF A LOGISTICS MODEL

C. E. Guest1, S. R. Blaha2 and J. P. Quaile3

ABSTRACT This document describes a model (the Phase 2 Logistics Model) developed to simulate the logistics of transporting and managing dredged sediment for the Hudson River Dredging Project (the project) being executed by the General Electric Company (GE) and discusses how the model supports the remedial design for the project. The dredging program is being performed to implement the remedy selected by the United States Environmental Protection Agency (EPA) to address polychlorinated biphenyls (PCBs) in sediments of the Upper Hudson River. The project encompasses approximately 200 hectares (500 acres) with a targeted removal volume of more than 1.5 million cubic meters (m3) (2 million cubic yards [yd3]) over approximately 64 kilometers (km) (40 miles) of river between Fort Edward and Troy, New York. The Upper Hudson River consists of eight pools that are separated by dams along the river. Locks associated with the New York Champlain Canal system allow for transport between the pools. Seven locks are located between the most downstream dredge areas and the Sediment Processing Facility. As part of the project, sediment is mechanically dredged, loaded into barges, and transported through the lock system to a Sediment Processing Facility for dewatering prior to being loaded into railcars for offsite transport and disposal. The model was developed to meet the challenges of modeling the multi-pool, multi-year Phase 2 dredging project. The logistics model simulates the sequence of the major steps associated with dredging, material transport, backfilling/capping, sediment processing, and rail yard operations (including transportation and disposal). Keywords: Dredged material transport, barges, capping, sediment processing, PCBs.

INTRODUCTION A logistics model was developed to support the Phase 2 design for the Hudson River Dredging Project. The model was developed by GE Global Research Center (GRC) in coordination with ARCADIS of New York, Inc. (ARCADIS). The model simulates the major steps of the project, including dredging, dredged material transport, backfilling/capping, sediment processing, and rail yard operations (including transportation and disposal). The model is a tool that can be used to provide insights into various design components. It can also be used:

to analyze scenarios such as the effect of adding or removing project resources (e.g., dredges, barges, tugs, offloading equipment);

to support adjustments to the proposed design, including evaluation and development of dredge plans and resource allocations;

to simulate a variety of conditions and constraints to assess potential bottlenecks in the dredging, dredged material transport, and backfill or capping activities; and

as a tool for communications and predicting time-based logistical information, such as the movement of project vessels, the potential impact of recreational traffic, interactions with the lock system, accumulation of processed material, and rail movement to the disposal site.

OVERVIEW OF THE HUDSON RIVER DREDGING PROJECT

The Hudson River is located in eastern New York State and flows approximately 480 km (300 miles) in a southerly direction from the Adirondack Mountains to New York City. In 2002, the EPA issued a Superfund Record of

1 Principal Engineer, ARCADIS U.S., Inc., 855 Route 146, Suite 210, Clifton Park, New York, 12065, USA,

T: 518.250.7377, Fax: 518.250.7301, Email: [email protected] 2 Project Engineer, General Electric Company, 381 Broadway, Bldg. 40-2, Fort Edward, New York, 12828, USA,

T: 518.746.5296, Fax: 518.746.5701, Email: [email protected] 3 Senior Research Engineer, GE Global Research, 1 Research Circle, Schenectady, New York, 12309, USA,

T: 518.387.5884, Fax: 518.387.7080, Email: [email protected]

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Decision (ROD) identifying the removal and disposal of PCB-contaminated sediments as the selected remedy for the Upper Hudson River (EPA 2002). The Upper Hudson River consists of eight pools that are separated by dams along the river. Locks associated with the New York Champlain Canal system allow for transport between the pools. Seven locks are located between the most downstream dredge areas and the Sediment Processing Facility. Figure 1 shows the Upper Hudson River.

Figure 1. Upper Hudson River

The project encompasses approximately 200 hectares (500 acres) with a targeted removal volume of more than 1.5 million m3 (2 million yd3) over 64 km (40 miles) of river between Fort Edward and Troy, New York. The remedy selected by the EPA calls for dredging in two distinct phases – Phase 1 and Phase 2.

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Prior to Phase 1 dredging operations, a land-based Sediment Processing Facility was constructed along the Champlain Canal north of Lock 7 in Fort Edward, New York to unload, dewater, and stage the dredged sediment prior to loading the materials into railcars for offsite transport and disposal. After construction of the Sediment Processing Facility, Phase 1 dredging operations conducted in 2009 included dredging, processing, and disposal of approximately 219,000 m3 (286,000 yd3) of sediment from approximately 19 hectares (48 acres; 10 certification units [CUs]) located in the most upstream portion of the Upper Hudson River. Phase 1 was a full-scale test of the dredging project, including the Hudson River Engineering Performance Standards established by the EPA (EPA 2004). The Engineering Performance Standards consist of resuspension during dredging and other in-river activities (the Resuspension Standard), concentrations of residual PCBs in surface sediments after dredging (the Residuals Standard), and seasonal production targets for the dredging project (the Productivity Standard). In 2010, after Phase 1 dredging operations, an independent Peer Review Panel reviewed separate Phase 1 Evaluation Reports prepared by the EPA and GE, held public peer review meetings, and issued a report that summarized the peer review of Phase 1 and recommended changes to the Engineering Performance Standards for Phase 2 (Bridges et al. 2010). In December 2010, the EPA issued its decision regarding the requirements for Phase 2, including Revised Engineering Performance Standards for Phase 2 (EPA 2010a). GE subsequently agreed to implement Phase 2 of the project. The first year of Phase 2 dredging (Phase 2, Year 1) was conducted in 2011 and included dredging, processing, and disposal of approximately 277,500 m3 (363,000 yd3) of sediment from approximately 30 hectares (75 acres; 15 CUs) downstream of the areas dredged during Phase 1. The second year of Phase 2 dredging (Phase 2, Year 2) is planned for 2012 to target the removal of at least 267,600 m3 (350,000 yd3) of sediment from 40 hectares (98 acres; 19 CUs). The remainder of Phase 2 dredging operations in the Upper Hudson River will target the removal of at least 267,600 m3 (350,000 yd3) of sediment each year until dredging is completed in all of the delineated dredge areas.

DESIGN OF THE PHASE 2 LOGISTICS MODEL The Phase 2 logistics model was developed to meet the challenges of modeling the multi-pool, multi-year Phase 2 dredging project. Consistent with the project design, the model simulates a mechanical dredging process with dredged material transported by barge. The model was designed to simulate or account for the sequence of major steps of the project and is subdivided into the following processes:

Dredging Processes o Inventory dredging (i.e., the first dredging pass to remove the targeted sediment) o Testing and CU certification (i.e., post-dredging survey, residual sediment sampling, re-dredge

decision process, and re-dredge prism design) o Re-dredging (if required)

Backfilling and Capping Processes o Backfilling o Capping o Testing and CU certification (i.e., backfill prism design, post-placement survey/sampling)

Barge/Tug Movement

o Transport of barges to/from the dredge areas, staging areas, the Sediment Processing Facility, and the Backfill Loading Facility

o River navigation, including lock cycles and interaction with recreational boats

Sediment Processing o Sediment and water unloading o Sediment processing/dewatering/staging

Rail Yard Operations

o Railcar loading o Movement of loaded railcars between the Sediment Processing Facility and the disposal facility

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Figure 2 presents a simplified flow chart illustrating the material flow process assumed in the logistics model.

Figure 2. Simplified dredged material flow process in the logistics model

The model logic is coded within AnyLogic Version 6.7 simulation software developed by XJ Technologies (http://www.xjtek.com), which allows for a combination of multiple simulation paradigms, and its structured object-oriented architecture facilitates model coding and understanding. The model is designed to emulate the planned operations and facilitate understanding of logistics by project designers. Its structure features familiar objects, such as dredges, tugs, and barges, whose characteristics and behaviors are modeled as “agents” or objects with embedded intelligence. These agents control the activities within the model. The model requires a variety of input data to define the areas and parameters of the dredging, material transport, and backfilling/capping operations. The key objects used in the model include:

Certification Units (CUs): The areas of the river delineated for dredging have been divided into CUs. In general, each CU is approximately 2 hectares (5 acres) in size.

Sites: Each CU is subdivided into dredge “Sites”, which are approximately 0.4-hectare (1-acre) sub-areas

of each CU and provide operable areas for modeling.

Areas: CUs are grouped into “Areas” to enable the control of dredging precedence and allow for dredging in multiple Areas at the same time. Areas are generally assigned to correspond to a geographical area within a pool targeted for removal during a specified dredging season.

Dredges: Dredges are resources that control dredging activity in each Site and load dredged sediment into

barges. Three different types/sizes of dredges can be specified in the model input.

Large Barges: Large barges transport dredged sediment from the dredge Sites to the Sediment Processing Facility.

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Small Barges: Small barges load sediment dredged from Sites with restricted access. Dredged sediment

loaded into small barges is transferred to large barges at Transload Stations prior to transport to the Sediment Processing Facility.

Transload Stations: Transload Stations transfer dredged material from small barges to large barges.

Sediment Processing Facility: The Sediment Processing Facility handles the unloading, processing, and

staging of dredged sediment. The Sediment Processing Facility is located along the Champlain Canal north of Lock 7.

Processing Facility Sediment Unloading Crane: The unloading crane unloads sediment from barges at the

Sediment Processing Facility.

Backfill Loading Facility: The Backfill Loading Facility is where empty backfill barges are loaded with backfill and cap materials.

Backfill Loading Cranes: Backfill loading cranes load backfill and cap materials onto empty backfill barges

at the Backfill Loading Facility.

Backfill Barges: Backfill barges transport backfill and cap material from the Backfill Loading Facility to backfill machines.

Backfill Machines: Backfill machines unload backfill barges and place the backfill and cap material at each

designated dredge Site.

Staging Area: The Staging Area is where tugs and barges originate at the start of the model simulation. It temporarily holds idle tugs, empty barges, and partially filled dredged material barges (i.e., barges that are not full enough for transport to the Sediment Processing Facility for unloading).

Tugs: Tugs move dredged material barges and backfill barges among Sites, CUs, Transload Stations, the

Staging Area, the Sediment Processing Facility, and the Backfill Loading Facility.

Locks: Locks control and transport vessels between pools.

Pools: Pools are sections of the river between locks. The pool objects manage vessel traffic from within and from locks located at either end of the pool.

Recreational Boats: Recreational boats compete with project vessels (barges and tugs) for lock access.

Rail Yard: The rail yard handles the train traffic between the Sediment Processing Facility and the disposal

facility.

Railcar Sets: Railcar sets are groups of railcars that travel together and transport processed sediment.

Locomotives: Locomotives move railcar sets.

Dispatcher: The dispatcher orchestrates the complex logistics involved in moving river-based assets (tugs, barges).

The primary processes simulated by the model are summarized in the following subsections.

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Dredging Processes Each dredge Site transitions through several stages to complete the entire sediment remediation process: inventory dredging to remove the targeted sediment inventory volume; re-dredging, if assumed; and backfill or capping. Dredging Dredging is the first of several linked and mutually dependent project elements. The inputs define the areas, quantities, and production rates for the dredging operations. The dredging process involves initial dredging (inventory dredging) to remove the volume of targeted design cut sediment and re-dredging, if assumed. Inventory dredging is conducted to remove a specified sediment volume from each Site. Once inventory dredging is completed, a decision process is undertaken to determine whether or not re-dredging is required at the Site. This decision requires a delay in between dredging passes to account for time related to post-dredging elevation confirmation, collection/analysis of residual sediment samples, and re-dredging decisions and design. The dredging process at each Site follows the procedure shown in Figure 3.

Figure 3. Overall dredging process at a site

The model allows for the specification of three different types/sizes of dredges and allows the designer to vary the number of each type of dredge to be used. Dredging production rates (for both sediment and water) can be adjusted for each Site based on the characteristics of the dredge area (e.g., sediment bed characteristics, water depths, sediment removal thicknesses). The volume of sediment and water that can be loaded into barges is constrained by the barge capacity (in terms of both volume and weight) and barge loading factors specified based on the available draft in each Site. Information regarding the amount and type of material (fine sediment, coarse sediment, and free water) loaded into each barge is retained by the barge to facilitate material segregation at the Sediment Processing Facility. The model also allows for the simulation of a gradual ramp-up of production where the number of available dredges can be specified on a weekly basis to model a staged mobilization of the equipment onto the river. Dredging Schedule and Sequence A fundamental principle in the modeling process is to decide the sequence of Sites for inventory dredging. The model inputs define the desired sequence for performing inventory dredging. Available dredges evaluate each Site on the preferred dredging sequence. Each search begins from the top of the preferred sequence and continues until a

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candidate Site is identified. The model attempts to follow the preferred sequence, but may deviate from the sequence if dredging at a desired Site is temporarily prevented due to the following dredging rules:

Area-Based Precedence Rule: The model allows the user to group CUs into separate Areas and define dependencies among Areas to specify the dredging precedence. This concept can be used to require the completion of dredging in specified Areas prior to commencing dredging in other Areas. One or more Areas may become “dredgeable” when inventory dredging in prior Areas, with specified dependencies, are completed. This concept is shown on Figure 4.

Figure 4. Area-based precedence example (figure developed by GRC)

Concurrent CU Dredging Rule: When an Area is opened, dredges will be allocated to Sites in the Area

based on availability. Inventory dredging of CUs in Areas will progress from upstream to downstream. The model allows the user to limit the contiguously grouped CUs where inventory dredging can occur simultaneously (i.e., concurrent CU dredging). Work may begin in the next CU downstream of the group only when inventory dredging in the farthest upstream CU is complete. This concept is shown on Figure 5.

The dredging operation (both inventory dredging and re-dredging) is further constrained by the maximum number of dredges allowed in a CU, the availability of dredges, the sizes of dredges allowed in a Site, and the work schedule. Transload Stations Small barges are specified for Sites unable to accommodate large barges for the dredging process due to physical characteristics of the river (e.g., shallow depth, limited access). To increase transportation efficiency, the small barges are not transported to the Sediment Processing Facility, but are sent to a local Transload Station, where the contents of the small barges are transferred to a large barge. Once filled, the large barge is sent to the Sediment Processing Facility for unloading. Backfill and Capping Processes Backfilling and capping operations are simulated after inventory and re-dredging operations are completed within a particular CU and after a time lag to account for survey, sampling, and the re-dredging decision and design process. The backfilling and capping operations are performed with backfill machines and backfill barges, the number of which is specified in the model input. The model also allows the user to specify a schedule for converting dredges to operate as backfill machines during the course of the season.

1. N = number of CUs where inventory dredging may be ongoing concurrently (input variable). 2. CUi-1 is the CU farthest downstream subject to inventory dredging. 3. Inventory dredging in CUi may not begin until inventory dredging in CUi-N is complete, unless CUi-N does not exist

(e.g., CUi-1 is the farthest upstream CU in the Area).

Figure 5. Concurrent CU dredging in an area (figure developed by GRC)

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The backfill/cap materials are loaded at a specified rate onto empty backfill barges at a Backfill Loading Facility. After the backfill barges are loaded, they are placed in a queue of full backfill barges that can be requested by backfill machines at CUs. When the backfill barges are unloaded, the empty barges are returned to the Backfill Loading Facility for additional loading. The inputs define the areas, backfill/cap thicknesses, and production rates for the backfilling/capping operations. The total time to complete backfilling operations is based on the estimated amount of fill material needed at each Site and the specified backfill production rates, which are inputs to the model. The time to complete capping is based on the specified capping rates the estimated amount of fill material needed for each capping layer and a pre-defined time delay to account for survey/sampling. Barge/Tug Movement Tugs move dredged material barges and backfill barges among Sites, CUs, Transload Stations, the Staging Area, the Sediment Processing Facility, and the Backfill Loading Facility. In the logistics model, tugs do not move small barges, dredges, or backfill machines. Instead, the model assumes that separate tugs (not included in the model) move these units. The model uses a dispatcher object to orchestrate the logistics involved in moving the river-based assets repositioned by tugs. The dispatcher manages queues of asset requesters and the assets that need to be moved. Asset requesters add themselves to queues as required during operations. For example, when a dredge has finished loading a large barge, it adds itself to a “Dredges waiting for large barges” queue. Likewise, empty barges are added to a “Barges waiting for tugs at dredges” queue. The dispatcher attempts to empty each queue by selecting the appropriate assets and assigning tugs to transport them as required. In the model, the dispatcher will select an available tug and assign it to one of the following “missions” to satisfy the needs in the queues:

Pick up a large barge at staging and deliver it to a dredge, a Transload Station, or the Sediment Processing Facility

Pick up a large barge at the Sediment Processing Facility and deliver it to staging, a dredge, or a Transload Station

Pick up a large barge at a Transload Station and deliver it to staging or the Sediment Processing Facility (depending on how full the barge is)

Pick up a large barge at a dredge and move it to staging or the Sediment Processing Facility (depending on how full the barge is)

Pick up a backfill barge at the Backfill Loading Facility and deliver it to a backfill machine Pick up a backfill barge from a backfill machine and move it to the Backfill Loading Facility

Figure 6 illustrates possible movements of project vessels among different location types.

CU

Staging Area

Transload

Site

Processing Facility

BackfillLoading Facility

Movement of Backfill Barges

Movement of large Barges

Movement of small Barges Figure 6. Tug transport missions (figure developed by GRC)

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River Navigation The time for project vessels to move between locations, such as the Sediment Processing Facility and the Sites, is calculated based on the combination of travel and lock operation times. Travel times are computed using the speed of the vessel and the total length of travel, which may encompass multiple pools. Travel times are calculated by dividing the distance to be traveled by the vessel’s speed. The effect of water current can be factored into the travel time computations by adding or subtracting the river current velocity from the vessel’s speed depending on the direction of travel. Lock Operations Locks receive vessels from adjacent pools and transport them north or south, as required. The model also creates random recreational boating traffic in both directions based on lock use records to simulate the interaction with project vessels. Each lock adds a time stamp to each vessel object and assigns it to queues depending on its type (tug, tug with barge, recreational boat). The model input allows the user to choose which vessels have priority in the accessing the lock (project vessels, recreational boats, or first arrival) The locks operate in a cyclic pattern of opening the north and south gates repeatedly. The lock process includes: opening of the incoming gate, allowing vessels to enter the lock, waiting for the change of water level in the lock, opening the outgoing gate, and allowing the vessels to depart. Sediment Processing The logistics model does not simulate the steps in the barge unloading process, which includes decanting of water from barges, the movement of barges into the unloading position, and the transfer of sediment to size separation equipment. Rather, the model uses an input value for the average targeted barge unloading rate that takes into account the summation of these processes. The time to complete barge unloading is calculated based on the offloading rate specified in the model input and the volumes of sediment and water within the barges. The unloaded materials are separated into three categories – fine materials, coarse materials, and water – based on the information logged during dredging of each Site. The fine and coarse materials are processed and transferred to staging piles at rates prescribed in the input file before being loaded into railcars (see Figure 2). After barges are unloaded at the Sediment Processing Facility, the empty barges are transported by tugs to a staging area in the river or directly to a dredge or Transload Station (see Figure 6). Rail Yard Operations The processed/staged materials are loaded into railcars and shipped to a disposal facility. Input variables associated with rail operations dictate the number of railcars per train set and the capacity of the railcars. The railcars are loaded one at a time with fine material and/or coarse material from the staging piles. After all railcars associated with a train set are loaded, the loaded train set is transported to the disposal facility by locomotives, the materials are unloaded at the disposal facility, and the train set returns to the Sediment Processing Facility. Rail transport between the Sediment Processing Facility and the disposal facility and the unloading of the railcars at the disposal facility are simulated based on assumed time intervals defined in the model input.

MODELING PROCESS

Input Development The Phase 2 logistics model has a user interface to enter input data using Microsoft Excel worksheets. The logistics model inputs are developed based on the characteristics of the targeted dredge areas, the design basis for the upcoming dredging season, and the experience gained during the previous dredging seasons. The logistics model requires various data for the following input categories to define the project-specific parameters and constraints:

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Area definitions (identification of: dredge areas defined by CUs, Areas, and Sites; Transload Stations;

barge Staging Areas; and backfill/cap material loading locations) Site parameters for dredging and backfilling/capping (sediment removal volumes, dredge/barge size limits,

dredging rates, material characteristics, barge loading information, free water production rates, backfill/cap thicknesses/volumes, backfilling/capping rates)

Preferred dredging sequence and precedence (dredge sequence, location) Dredging resources (number and size of dredges, Transload Stations, backfill equipment, barges, tugs) Dredge ramp-up and dredge transitions (number and timing for active dredges at the start of the season and

for dredges that convert to backfilling equipment at the end of the season) Processing parameters and processing ramp-up (barge unloading rates, coarse/fine processing rates) Lock parameters (lock cycle times, lock priority, lock schedule) Rail yard parameters (railcar capacity, loading and unloading rates, travel times to/from the disposal

destination) Recreational boat information (recreational boats that may interact with project vessels for lock access) Season dates (dredging and rail yard operational season start dates and holidays) Work schedule (dredging, Processing Facility operating, and Backfill Loading Facility schedules)

Modeling Simulations The model includes a graphical user interface while the model is being run. The user interface includes two main screens: 1) a “cockpit dashboard” that displays real-time details of the simulation as it progresses; and 2) geographic information system (GIS) based mapping that displays a graphical summary of the simulated work progress. These interfaces allow the user to follow the progress of work as the simulation progresses and can be used for troubleshooting if a bottleneck occurs. Details available on the “cockpit dashboard” include:

The timing of the simulation, such as the year, week, and day being simulated Major milestones, such as dredging, backfill, and rail transport completed A progress chart showing the status at the CU level (i.e., unopened, dredging, backfilling, closed) Graphs of resource queues and the quantity of materials in staging piles at the Sediment Processing Facility The status of each Site and CU The simulated locations of all assets (e.g., dredges, large and small barges, backfill equipment)

A screen shot of the cockpit dashboard is shown in Figure 7.

Figure 7. Graphical “cockpit dashboard” interface

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A second user interface incorporated into the logistics model includes maps that show the location of each pool and each CU. Superimposed on the maps are boxes that display the status of the simulated dredging and backfill activities in each CU. A screen shot of this mapping interface for a portion of the Hudson River is shown in Figure 8.

Figure 8. Graphical mapping interface Modeling Output The model output data are summarized in Microsoft Excel files at the conclusion of each simulation. The output data can be processed manually or using macros to produce charts to analyze the predicted operations and assess where and how the model inputs should be adjusted to achieve the modeling objectives. Various scenarios can be modeled by adjusting the model inputs to simulate different assumptions and evaluate how changes to these assumptions affect the predicted outcome. For example, several modeling iterations can be performed to: evaluate the number of resources for achieving assumed production goals or schedule requirements; analyze the effect of adding or removing project resources; and/or assess potential bottlenecks in the operations.

DESIGN APPLICATIONS The Phase 2 logistics model was initially presented in the Phase 2 Intermediate Design Report (ARCADIS 2008). As part of the Phase 2 intermediate design, the logistics modeling included a sensitivity analysis to examine whether the target volumes established under the Productivity Standard (EPA 2004) could be removed while completing inventory dredging, residuals dredging, and backfill activities within the available construction season. Based on the lessons learned during Phase 1, the logistics model was updated and expanded to improve the simulation of dredging and backfilling/capping operations. To support the final design for Phase 2, Year 1 (ARCADIS 2011), the logistics model was used to develop a design dredge plan as required by the EPA (EPA 2010b), including the estimated dredging duration for each dredge area, sequencing of sediment removal by dredge area, estimated number of dredges to be employed, estimated hours of operation, and estimated weekly productivity. In addition, to support the design for Phase 2, Year 1, output data from the logistics model were used as input data to a separate resuspension model that is used to evaluate compliance with the Resuspension Standard (EPA 2010a). Similar modeling evaluations and design applications are being developed for Phase 2, Year 2, which is scheduled for implementation during 2012.

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Figures 9, 10, and 11, respectively, summarize the weekly dredge volumes, dredging schedule/sequence, and Lock 7 operational data based on output from the logistics model simulations developed for Phase 2, Year 1 (ARCADIS 2011).

Figure 9. Volume of sediment dredged by week based on logistics model output data

for phase 2, year 1 simulations

Figure 10. CU dredged by day based on logistics model output data


Figure 11. Vessels passing through Lock 7 by day based on logistics model output data


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As illustrated on these figures, the logistics modeling predicted that the dredging of approximately 275,200 m3 (360,000 cy) could be completed within 15 CUs in the 22-week period assumed in the basis of design and that the backfilling/capping operations could be completed prior to the anticipated closing of the locks in mid-November. These results compare well with the actual production data during Phase 2, Year 1 in 2011, for which approximately 277,500 m3 (363,000 yd3) of sediment were dredged from 15 CUs over 23 weeks (although the actual weekly production quantities and the actual dredging schedule and sequence for Phase 2, Year 1 differed from the logistics model simulation).

SUMMARY The Hudson River Dredging Project is a large and complex project that involves many operations and numerous resources. The Phase 2 logistics model has been a useful tool for simulating the operations associated with this multi-faceted project and providing dredge plan information to support the remedial design. The modeling efforts have provided valuable insight related to the ability to achieve the targeted production goals for the dredging operations. The logistics model is expected to become more insightful as the dredging operations advance farther south into the downstream reaches of the river, where dredge areas are spaced farther apart, material transport durations will increase and vessels will need to maneuver through multiple locks en route to the Sediment Processing Facility.

REFERENCES ARCADIS of New York, Inc. (ARCADIS). 2008. Phase 2 Intermediate Design Report for the Hudson River PCBs

Superfund Site. Prepared for General Electric Company, Albany, NY. May. ARCADIS. 2011. Phase 2 Final Design Report for 2011 for the Hudson River PCBs Superfund Site. Prepared for

General Electric Company, Albany, NY. Revised April. Bridges, T., Fox, R., Fugelvand, P., Hartman, G., Magar, V., Schroeder, P., and T. Thompson. 2010. Hudson River

PCBs Site Peer Review of Phase 1 Dredging Final Report. With contributions from SRA International, Inc. September 10.

U.S. Environmental Protection Agency (EPA). 2002. Hudson River PCBs Site, New York. Record of Decision. EPA. 2004. Statement of the Engineering Performance Standards for Dredging. Hudson River PCBs Superfund

Site. April. EPA. 2010a. Hudson River PCBs Site Revised Engineering Performance Standards for Phase 2. Prepared by the

Louis Berger Group, Inc. for EPA and United States Army Corps of Engineers. December. EPA. 2010b. Critical Phase 2 Design Elements (Attachment A to the Revised Statement of Work for Remedial

Action and Operations, Maintenance, and Monitoring, which is Appendix B to the Remedial Action Consent Decree between GE and the United States [Civil Action No. 1:05-CV-1270] for the Hudson River PCBs Superfund Site). December.

Quaile, J., Petersen, M., and Wang, S. 2011. Logistical Simulation for Complex Dredging and Sediment Transport in the Hudson River. Institute for Operations Research and the Management Sciences, Northeastern Conference, May 6-7.

CITATION

Guest, C. E., Blaha, S. R., and Quaile, J. P. “Hudson River dredging design – application of a logistics model.” Proceedings of the Western Dredging Association (WEDA XXXII) Technical Conference and Texas A&M University (TAMU 43) Dredging Seminar, San Antonio, Texas, June 10-13, 2012.

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