Key words: dredged material disposal, beneficial use, dredging policy

The New York/New Jersey Harbor is naturally shallow with a reported natural depth of about 18 feet. The Harbor has been dredged since the late 1800's to provide sufficient draft for vessels of increasing size. Currently, channel depths in the Port of New York and New Jersey are as deep as -40 feet below the plane of mean low water (MLW). Additional deepening of the channels has recently begun to bring their depths to -45 MLW and studies are on going which could further increase channel depths to -50 MLW. Since dredging in the New York Harbor began, dredged material has been disposed of in the ocean about six miles off the coast of New Jersey. In the early 1990s, New Jersey's philosophy concerning dredged material management began to shift away from mere disposal of dredged material to a comprehensive management strategy centered on the beneficial use of dredged material. In 1997, the Mud Dump, which had for years been used to dispose of millions of cubic yards of dredged material from the Port of New Jersey and New York, was officially closed which left the largest port on the Eastern Seaboard with virtually no dredged material disposal alternatives. Consequently, the transition to beneficial use took on new urgency in 1997.

In response to the impending crisis, the New Jersey Department of Environmental Protection and private sector partners began an innovative program aimed at using dredged material from the New York Harbor to facilitate the closure of abandoned landfills and the remediation of brownfield sites in the metropolitan region. The primary goal of the program is to successfully manage dredged material in a manner that is protective of human health and the environment. An added benefit of the program is the remediation of contaminated upland sites in urban areas and their restoration to economic use. The first site to be successfully remediated using dredged material was the Elizabeth Landfill, now home of the Jersey Gardens Mall. This management strategy is presently being expanded to other areas of the State including the Delaware River, thereby renewing capacity at existing confined disposal facilities and eliminating the need to expand or site new facilities.

This paper will provide a brief chronicle of the emergence of New Jersey's dredged material management policy and its implementation through existing regulatory programs, and the development of New Jersey's dredging technical manual. The paper will focus on regulatory considerations for determining acceptable uses for dredged material including sampling frequency, testing protocols and choosing appropriate evaluative criteria, and will present an upland beneficial use case study of a currently active brownfield redevelopment. Lastly, the paper will discuss impediments to the success of the program and on-going research initiatives intended to address outstanding questions including the volatility of contaminants.

*Corresponding author: telephone (609) 292-9203

fax: (609)777-1914

email: sdietrick@dep.state.nj.us

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The Equilibrium Partitioning (EqP) model is the basis for our current ability to understand and predict the causes of toxicity in sediments. It also forms the framework for toxicity identification evaluations (TIEs) in sediments. The data that support the assumptions in the model will be reviewed for both organic chemicals and metals. Recent applications of EqP to predicting the toxicity of mixtures of polycyclic aromatic hydrocarbons (PAHs) in sediments using narcosis theory will be presented. An extension of the simultaneous extracted metal-acid-volatile sulfides (SEM-AVS) model to improve the prediction of toxicity of metals in sediments - in addition to its already demonstrated ability to predict the lack of toxicity - will also be discussed. Finally the limitations of the EqP model for organic chemicals and metals will be examined, particularly from the point of view of evaluating dredged materials.

*Corresponding author: dditoro@hydroqual.com
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Key words: beneficial use, contaminated sediments, dredging, decontamination, stabilization

Faced with a dredged materials backlog of almost 6 million cubic yards and an impending navigational crisis, the State of New Jersey instituted widespread changes on regulatory, legal and policy levels in the way dredged materials are managed throughout the State. Two completely new offices were created to successfully implement this innovative new program, which emphasized dredged materials as a resource rather than a waste. Upland beneficial reuse was essentially unproven, however, and the regulated community was not optimistic about its ability to perform in a manner consistent with project goals and objectives. Over $250 million in combined funding from the Port Authority of New York and New Jersey and a statewide referendum provided the resources necessary to perform pilot and demonstrations of new technologies. Projects were chosen for testing based on their ability to meet objectives on sediment reduction, contaminant reduction, and beneficial reuse reduction potential. Beneficial use projects were shown to result in not only increased disposal capacity, but also remediation and reclamation of abandoned industrial properties. An extensive contaminant monitoring and source trackdown program is underway to and will result in a plan to reduce the amount of contaminated materials that must be managed. Sediment decontamination technology demonstrations, following the groundbreaking work of the USEPA/WRDA program have been initiated and if successful may provide additional reuse capacity as well as a cost- effective manner for treatment of highly contaminated sediments. The overall progress of these programs will be discussed as well as lessons learned and a blueprint for future efforts.

*Corresponding author: telephone: 609-984-8564
fax: 609-984-1468
email: scottdouglas@dot.state.nj.us

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¹Menzie-Cura & Associates, Inc., Chelmsford, Massachusetts USA; ²United States Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi USA

Managers in New York and New Jersey Harbor are developing strategies to dispose and manage large volumes of sediments that must be dredged in order to maintain passable waterways. A number of alternatives are available including aquatic containment facilities, upland containment, treatment, and beneficial reuse. An important consideration in the selection of an appropriate alternative is the evaluation of potential risks to ecological and human receptors. This study presents the results of a prospective screening-level ecological and human health risk assessment that compares risks associated with management alternatives for contaminated dredged materials. The major objectives of the work were to identify exposures that show the potential for risk and cause for concern, develop a framework for a comparative risk assessment, and compare relative potential risks among eight management alternatives. The results can be used by managers to identify specific characteristics of the placement/treatment alternatives that may increase the potential for risk, chose one alternative over another for sediments with high concentrations of certain contaminants, implement controls that mitigate risk, or identify the need to a more comprehensive site-specific risk assessment.

*Corresponding author: telephone: 978-453-4300
email: driscols@menziecura.com

fax: 978-453-7260

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Key words: geotextile containers, dewatering, impoundment sediment

The purpose of this paper is to describe the application of the Dry DREdge™ technology coupled with Geotubes in the dredging and dewatering of hazardous sediments. The paper describes the project objectives, the Dry DREdge™ and Geotube technologies, and the results of applying this technique. The Dry DREdge™ was jointly developed and tested by DRE and the U.S Army Corps of Engineers, Waterways Experiment Station (WES), Vicksburg, MS, under the Corps of Engineers Construction Productivity Research Program (CPAR). TC Mirafi and WES also developed the use of geotubes to contain fine dredged sediments under the CPAR program. The fine-grained hazardous sediments were dewatered and passed the paint filter test by the third week after dredging and filling the geotubes. This project resulted in a one million dollar savings to the client.

*Corresponding author: telephone: 601-636-5475

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'Sludge from the Rhine': that's what Napoleon Bonaparte called the Netherlands back then. Although intended as an insult, this is an apt description of the Dutch landscape, given the enormous deposits of sediment in the 'settling basin' that the Netherlands just happens to be. The figure below shows the close relation between land and water in the Netherlands. Although the quality of this sediment is now somewhat better, in the seventies and eighties it was anything but clean. As a heritage from the past, we expect that for the period from 2000 to 2010 alone, about 200 million m³ of heavily polluted sediment will be dredged. These sediments originate both from environmental (remediation) as well as maintenance cases.

Does this mean that nothing has ever been done about this problem before? Certainly not. Since the nineties, major progress has been made together with many national and international partners in tackling and improving our knowledge of contaminated sediments. Together, we have conducted extensive research, formulated policy, set guidelines, built large-scale disposal sites, performed remediation and reused dredged material within its area of origin. The Dutch Ministry of Transport, Public Works and Water Management plays a major role concerning the removal and disposal of contaminated sediment.

Recently a large-scale study involving an evaluation (cost and environment) of sediment treatment and disposal options showed once again the necessity of regional disposal sites. The same study also concluded that about 30% of the disposed contaminated sediments could be reused using simple techniques like sedimentation basins. Other recent studies have shown the feasibility of the use of local pits for the long-term storage of contaminated sediments.

*Corresponding author: telephone +31 (30) 2858074
email: J.K.Eenhoorn@BWD.RWS.MINVENW.nl

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Key words: wetland creation, Toronto, contained disposal facility

The Confined Disposal Facility (CDF) for the Port of Toronto is operated by the Toronto Port Authority and consists of three disposal cells (49 ha. In size), within Tommy Thompson Park (TTP). Tommy Thompson Park is a spit of land on the central Toronto Waterfront that extends southwest into Lake Ontario for 5 km. Since 1982, the park has been the repository for sediments dredged from the mouth of the Don River and other locations within the Toronto Harbour.

Dredging and disposal operations were approved under the Provincial Environmental Assessment Act, subject to a number of conditions. One condition dictates that the cells within the CDF "be topped off and capped in a manner which restricts biological uptake and mobility of contaminants." The Toronto and Region Conservation Authority (TRCA) is the government organization responsible for determining the long-term use of the CDF site. Following extensive studies of the existing environmental conditions within Cell 1 and after evaluation of the economic and engineering considerations of the project, the TRCA and the Toronto Port Authority is proposing the use of a sub-aqueous clean-fill cap and wetland creation at the site.

To test the feasibility of a cap and wetland the TRCA developed a similar proposal for the Triangle Pond area within TTP. The triangle pond is a one-hectare water body centrally located within the park that was constructed in the early 70's to test the feasibility of developing a large scale CDF for the harbour. The capping construction was completed over the course of six months in 1999 and a variety of wetland vegetation has been established through plantings and colonization over the past growing season.

The wetland at Triangle Pond and our proposed wetland at Disposal Cell one will enhance opportunities for public education and recreation, wildlife habitat improvement, and increase ecosystem diversity. In addition, our use of a Clean-fill/Wetland at Tommy Thompsonm Park may demonstrate what can be achieved in the way of wetland creation at other Great Lakes CDFs.

*Corresponding author: telephone: 4116-661-6600 x5246
email: gord_macpherson@trca.on.ca

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Key words: risk, sediment quality criteria, open ocean disposal

Every year, approximately 4 million cubic yards of sediment are dredged for maintenance of the New York/New Jersey channels and Newark Bay. The U.S. Army Corps of Engineers (U.S.ACE) employs a framework of sediment quality criteria (SQC) to determine whether the contaminant levels in the sediments are suitable for open ocean disposal (i.e., would not pose a health risk) or whether more extensive and costly disposal methods are required. The SQC have been developed over a period of several years, using a variety of different risk assessment methods. The purpose of our analysis was to assess the degree of consistency in the risk assessment methods used to derive the SQC, and to determine whether a single, refined approach might yield significantly different SQC. We also reviewed 15 permitting decisions over the last 10 years and determined whether different disposal decisions would have been reached using a single set of consistently derived SQC. Our findings may be summarized as follows: First, the risk assessment methods vary significantly across the approximately 30 chemicals for which SQC exist. While some SQC are classically "risk-based", others are based on historical background concentrations, some are based on U.S. Food and Drug Administration (U.S.FDA) action levels, and some are based on limits of detection (dioxin). Hence, the degree of conservatism and health protection in the SQC is quite different for different chemicals. Second, consistent application of the "risk-based" methods developed by U.S. ACE and U.S. Environmental Protection Agency (U.S. EPA) Region II to all chemicals yields very different SQC for some constituents, and this can have a significant impact on the decision-making process. Specifically, we found that, if purely "risk-based" criteria had been used over the last 10 years, then: 1) at least 40,000 cubic yards that were granted open ocean disposal would have failed one or more "risk-based" SQC, 2) at least 150,000 cubic yards that were denied open ocean disposal would have been considered suitable for this option, and 3) at least 700,000 cubic yards that were denied open ocean disposal due to trace levels of dioxin would have "passed" a risk-based SQC for dioxin. These findings further illustrate the need for a consistent, valid, and risk-based approach for contaminated sediment management decisions.

*Corresponding author: telephone: 707-535-0492
fax: 707-535-0489
email: bfinley@exponent.com

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Key words: Geographic Information Systems (GIS), decision making methodologies, dredging, interactive, site selection, Boston Harbor, consensus building, adaptive management

Each year regulators, scientists, environmentalists, and citizens who affect the quality of our environment make thousands of decisions. While most of these decisions are made on the basis of the best available information and with good intentions current decision-making methodologies leave much to be desired.

Current Decision-Making Methodologies are limited by:

• A-Priori Decisions

• Lack of Public and Scientific Input Early in the Process

• Inadequate Documentation of Assumptions

• Lack of a Holistic View

• Inadequate Consensus Among Stakeholders

• The Inability to Review, Revise and Adapt Decision on the Basis of New Information

With this in mind, a new Decision-Making Methodology was developed that utilizes Geographic Information Systems (GIS) as an implementation tool. This methodology was examined using the case study of locating dredged material disposal sites in Boston Harbor.

Site selection is an inherently political process based on interpretations and perceptions of the underlying science. To address this a two-part process for evaluating, ranking, and weighting the information that leads to a decision was adopted. In the first part data are presented as ranked GIS layers based on expert scientific knowledge. Subsequently, the public, stakeholders, and decision makers weight, combine and evaluate all of the available information (presented as GIS layers) leading to a consensus decision. This allows for public involvement and decision making to build upon good science and scientific interpretation of data.

The development of an interactive GIS provides the tools needed to implement this methodology. The use of visual analysis, a holistic approach, and better documentation of the assumptions inherent in any decision contribute to the adaptive management approach of this process. In addition, the interactive capability of GIS allows 'what if' scenarios to be examined and allows users to immediately understand the various factors and tradeoffs involved in any decision.

This new Interactive GIS-based methodology has several advantages over conventional methodologies. The advantage of the new methodology is that:

• It's an interactive and user friendly process

• Decisions are based on a solid scientific foundation

• Inclusion of a universe of information is possible with few spatial constraints

• A collaborative, consensus building process can be facilitated

• Results are immediately available, repeatable, and can be revised on the basis of new information.

• Assumptions are visible and documented

Feedback from public demonstrations of the proposed methodology confirms that this approach to decision-making is an improvement over current methods. Because it aids consensus building and fosters an interactive, adaptive management approach, this methodology has the potential to allow decisions to be reached in less time, with less cost, and with greater numbers of stakeholders, citizens and decision makers satisfied that a good and proper decision was reached.

*Corresponding author: telephone: (781) 849-7070 x 290
fax:(781) 849-0096
email: sfitzgerald@daylor.com

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Key words: mud, sediments, dredging, beneficial use, habitats, sustainability, coastline

The shape of our coastline is constantly changing due to the impact of natural processes and man made influences. Coastal areas are under threat from flooding and in many regions sea defences are eroding. Traditionally, heavy engineering has been used to protect coastal areas and high costs have been encountered. New schemes and trials, which combat the changes and impacts on our coastlines have started to be undertaken throughout Europe on a small scale and these have been termed coastal realignment schemes. Coastal realignment schemes are a relatively new approach and may involve letting existing land flood and setting the coastline back, more commonly termed managed retreat, or placing material in front of coastal walls and sea defences and building forward. This paper focuses on the placement of dredged material for building forward of coastal sea walls and sea defences.

HR Wallingford undertakes a number of projects dealing with the beneficial use of dredged material in the marine environment. Of particular interest is the increase requirement to explore the practical, technical and socially acceptable use of muddy dredged material. HR Wallingford are shortly to complete a Ministry of Agriculture, Fisheries and Food (MAFF) funded project which involved monitoring schemes where muddy (maintenance dredged material) is placed at estuary sites. This paper reviews the process in the UK for undertaking such projects and practicalities involved. It will summarise the lessons learnt from a number of sites where dredged material has been used beneficially for habitat creation. Case studies include salt marsh recharge, mud flat creation and trickle charge feeding of sediments into the estuary system via water column and sub-tidal placements.

*Corresponding author: telephone: +44 (0)1491 835381
fax: +44 (0)1491 832233
email: caf@hrwallingford.co.uk

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Key words: geotextile containers, fine grained dredged material, split hull bottom dump scows, shallow water habitat (SWH), confined aquatic disposal (CAD)

Approximately 42,000 m3 (55,000 cubic yards, cy) of contaminated maintenance dredged material has been successfully contained in geotextile containers and placed with split hull bottom dump barges in a shallow water habitat and capped with a layer of clean sandy dredged material. The dredged materials contained about 7 to 8 percent fine grained soil and were contaminated with lead, zinc and copper. The materials were mechanically dredged with a clamshell bucket and placed in geotextile containers. The containers were sewn closed and placed within the Port of Los Angeles' (POLA) Shallow Water Habitat (SWH) Confined Aquatic Disposal (CAD) site. Forty-four geotextile containers were filled with an average of about 992 m3 (1300 cy) of contaminated maintenance dredged material from the Marina Del Rey, California, channel entrance and the Ballona Flood Control Channel, Los Angeles, California. Dredging began November 10, 1994 and was completed December 18, 1994. An average of 1.5 containers or 1527 m3 (2000 cy) were placed each day using a Differential Global Positioning system. This was the first project of its kind in the world where contaminated dredged material was successfully contained in geotextile containers, placed, and capped with a sand layer.

At the same time as the Marina Del Rey project, the Port of Oakland, California, was in mechanically excavating contaminated maintenance dredged material into a holding barge and then pumping it into geotextile tubes for dewatering and subsequent landfill disposal. Geotextile tubes were successfully filled with contaminated dredged material and allowed to drain to about 40 to 65 percent of their original volume prior to landfill placement.

As a result of these two demonstration projects, there are several similar projects being designed by the New York-New Jersey Port Authority, New York, New York and the Massachusetts Port Authority, Boston, Massachusetts. These new and innovative concepts of containing contaminated dredged material in geotextile containers have proven to be constructably practical, technically and economically feasible and environmentally acceptable compared to other disposal alternatives.

*Corresponding author: telephone: 601-636-5475

Key words: geotextile, containers, geotubes, dewater, contaminants, beneficial uses

Municipal sewage sludge was place in geotextile bags for the purpose of evaluating the dewatering and consolidation capabilities of large geotextile tubes and effluent water quality. A proposed ASTM test method for determining the flow rate of suspended solids from a geotextile containment system for dredged material was used to conduct tests to determine the efficiency of different combinations of geotextile filters. Prior to filling the large geotextile tube, two small geotextile bags 48 inches in circumference and 70 inches long were supported vertically in a wooden frame and filled to a depth of about 60 inches or about 48 gallons of sewage sludge from the primary sludge digester. As water passed through the geotextile bag, samples were collected during, immediately after and for several days to determine the total percent suspended solids (TSS), heavy metals, and bacterial count. The test results indicated significant consolidation or reduction in the volume of the sludge volume in the bag. There was also a significant reduction in the TSS, heavy metals, and bacterial count in the effluent water. These test results led to filling a large geotextile tube 15 ft wide, 30 ft long and filled to a height of 5 ft with sewage sludge.

The quality of pore water or effluent passing through the geotextile container systems proved to be environmentally acceptable for subsequent discharge into the Mississippi River and/or return to the treatment plant.

This new and innovative technology has been successfully used to dewater fine grained, contaminated dredged material that contained dioxins, PCBs, PAHs, pesticides and heavy metals for Miami River and the Port of Oakland, California. This is the first successful use of geotextile tubes for dewatering sewage sludge for beneficial uses in the United States. Research using this process for dewatering pork and dairy farming waste, paper mill waste, fly ash, mining waste, chemical sludge lagoons and several other waste streams are being conducted.

This concept of containing sewage sludge has proven to be construction-practical, technically and economically feasible and environmentally acceptable.

*Corresponding author: telephone: 601-636-5475

One of the first Geotube applications in Colombia was for construction of confined disposal area islands that will be used for containment and dewatering of fine-grained maintenance dredged materials. The project is located on the San Antonio Inlet, Buenaventura Colombia. The dredged material containment area is the first of two oval shaped islands planned in this riverine and tidal environment. This new and innovative construction methodology involved hydraulically filling geotubes with a sandy fill material. Geotubes are simply an assemblage of geotextile fabric panels sewn to form long tubes for containment of dredged material. The geotubes were positioned end to end to provide a perimeter dike for dredged material containment in tidal variations of 4-meters twice a day. After the oval shaped islands are completed they will serve as dredged material containment facilities until they are filled and stabilized. After they are stabilized they will be planted in Mangrove trees and other native vegetation and will be used exclusively for environmental purposes.

*Corresponding author: telephone: 601-636-5475

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Key words: Confined Aquatic Disposal (CAD), capping, dredged material disposal, monitoring

The dredging, filling, and capping of nine Confined Aquatic Disposal (CAD) cells for the Boston Harbor Navigation Improvement Project provided an ideal opportunity to improve construction methods and monitoring approaches for this emerging management approach. Working with the project Technical Advisory Committee and the Massachusetts regulatory agencies, we modified CAD design requirements based on experiences gained in each successive phase of the project. In 1997, the use and monitoring of a single CAD cell lead to construction changes in cap placement for the Phase II in-channel disposal cells. Additional experience with the first three, larger Phase II cells in 1998 resulted in adoption of recommendations to increase consolidation time to times spanning four to six months prior to capping and minimize the use of the props on the hopper dredge during capping. These approaches were applied to the last five cells created by the project in 1999/2000 resulting in even higher levels of success than in the earlier cells. CAD cells can provide a practicable alternative for contaminated sediment management. The success and experience gained from projects such as the Boston Harbor Navigation Improvement Project will certainly increase the environmental acceptability of CAD cells as a management alternative.

*Corresponding author: telephone: 978-318-8291
fax: 978-318-8303
email: thomas.j.fredette@usace.army.mil

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