Evaluating Construction Activities Impacting on Water Resources Part III A: Handbook for Dredging and Dredged Material Disposal in Ontario - Legislation, Policies, Sediment Classification and Disposal Options

Foreword

In l976, the Ontario Ministry of Environment (OMOE) published the guideline "Evaluating Construction Activities Impacting on Water Resources" as an aid in the assessment of the environmental impact of construction activities. The document was subsequently updated in 1984 and 1995.

The revised guidelines were divided into five parts, as follows:

Part I: Guidelines for construction of hydrocarbon transmission and distribution pipelines crossing water courses (March 1984)

Part II: Guidelines for construction of highways and bridges (March 1984)

Part III: Handbook for dredging and dredged material disposal in Ontario A,B,C

1. Legislation, Policies, Sediment Classification & Disposal
2. Dredging, Transport and Monitoring
3. Sediment Sampling and Laboratory Analysis (November 1990, Revised January 1994, Updated January 2011)

Part IV: Guidelines for marine construction projects (April 1986)

Part V: Guidelines for small-scale waterfront projects (April 1986)

In 1995, Parts I, II, IV and V were revised again to reflect more recent approaches to sediment and erosion control and were consolidated into one document entitled "Guidelines for Evaluation Construction Activities Impacting on Water Resources" (1995). Part III continues to be available separately.

In 2011, minor modifications were made to this handbook to update sections with current information (e.g. update references to legislation, policies, agencies, etc.). However, no changes were made to direction or guidance provided in this document.

This handbook (Dredging and Dredged Material Disposal - Part III) has been prepared to assist dredging project proponents, OMOE staff and staff of other regulatory agencies in the selection of safe and appropriate management methods based on dredged material characteristics and current OMOE legislation. This document is intended to be a reference handbook of dredging-disposal activities, the details of which may not be required on a routine basis. The current revision incorporates the new sediment evaluation procedures from the ministry document entitled, “Guidelines for Identifying, Assessing and Managing Contaminated Sediments in Ontario: An Integrated Approach” (OMOE, 2008) which replaces the Provincial Sediment Quality Guidelines (Persaud et al. 1992).

Mention of trade names and commercial products in this handbook does not constitute endorsement.

Acknowledgement

The preliminary report was originally prepared under contract by Beak Consultants and Ocean Chem Group.

This report underwent review and consequently many modifications were made based on valuable comments from the following people: Dredged Material Management Working Group, Steve Maude, Gerry Myslik, Archie McLarty, Duncan Boyd, Deo Persaud, Wolfgang Scheider, John Ralston, Tammy Lomas, Don King, Ian Carter and Elizabeth Pastorek from the Ontario Ministry of the Environment, and Ian Orchard, Laurie Sarazin, John Marsden, Susan Humphrey, Simon Llewllyn, Alfred Chau, Peter Fowlie and Bill Lee from Environment Canada.

Tammy Lomas and Stephen Petro of the Water Resources Branch, Ontario Ministry of the Environment coordinated editorial revisions to the report.

Special thanks to Rose-Marie Gonsalves of the Water Resources Branch, Ontario Ministry of the Environment for her endurance in typing the many editorial revisions. Jim Martherus prepared the figures. Field crew from the Great Lakes Section, Ontario Ministry of the Environment and W.D. Wilkins collected field samples near the Burlington Canal.

Volume III of the Ontario Ministry of Environment’s Report-Evaluating Construction Activities Impacting on Water Resources was supported in part by funds received from Environment Canada under terms of the Canada-Ontario Agreement (COA) on Great Lakes Water Quality. Activities are coordinated with those of the Federal Government under the guidance of the COA Polluted Sediments Committee.

The revisions made to this document in 2011 were coordinated by staff in the Ontario Ministry of the Environment’s Eastern Region with the assistance and expertise from staff from the Ontario Ministry of the Environment’s Environmental Monitoring and Reporting Branch, Standards Development Branch, Operations Division (Technical Support Section), and Legal Services Branch.

Introduction

Environmentally sound marine construction practice requires that every effort be made to preserve the physical and biological integrity of Ontario’s waterbodies in accordance with the provincial goals - "To ensure that the surface waters of the Province are of a quality which is satisfactory for aquatic life and recreation" (Ontario Ministry of the Environment, 1994).

The aim of this Ontario Ministry of Environment handbook is to provide an overview of the management options for the handling of dredged material in the Province of Ontario. These guidelines were developed to protect the receiving environment according to the physical, chemical and biological quality of the material being dredged. Recognition is given, where appropriate, to the potential re-use of certain materials.

Dredging for the purposes of this handbook is identified as the planned, mechanical movement of material located below the surface of a waterbody, or at the land/water interface. These guidelines apply to all forms of dredging.

Prior to any dredging activities, permits and approvals may be required under different legislation. The following sections review the federal, provincial and municipal legislation and policies and as well, sediment classification and disposal. This document is not intended to provide legal advice and it should not be construed as such. The relevant and applicable legislation should be reviewed and considered before proceeding with a project. Updates and amendments to legislation can be accessed through the e-Laws website.

Dredging activities undertaken by the provincial and municipal governments are subject to the requirements of the Environmental Assessment Act, R.S.O. 1990, c. E. 18 as amended. Consideration needs to be given as to whether any exemptions would be applicable to a particular dredging project. Generally speaking, environmental assessments have to identify the potential environmental impacts of all aspects of a project, as well as identifying proposed mitigation measures, the consequences of not performing the project, etc.

Various types of approvals may also be required for work in streams and lakes. For example, the removal of contaminated sediment from a stream using cofferdams and excavating equipment may require approval under one or more federal or provincial pieces of legislation.

Sediments are classified into two groups, contaminated or uncontaminated, based on a set of numerical guidelines. Once the sediments have been evaluated, several disposal options are available and depending on the degree of contamination, one method is selected.

Federal Legislation Policies (1.0)

This category can be divided into two groups: federal legislation applying to all proponents, and legislation and policies applying only to federal government departments.

Canadian Environmental Assessment Act

The Canadian Environmental Assessment Act, R.S.C. 1992, c. 37 (CEAA) is administered by the Canadian Environmental Assessment Agency. The Canadian Environmental Assessment Agency is an independent agency that reports directly to the federal Minister of the Environment. The CEAA requires that federal departments, including Environment Canada, agencies, and crown corporations conduct environmental assessments for proposed projects where the federal government is the proponent. It also requires environmental assessments when the project involves federal funding, permits or licences.

The CEAA and its regulations set out the legislative responsibilities for the environmental assessment of projects that involve the federal government. The CEAA has four fundamental purposes:

• to ensure that the environmental effects of projects receive careful consideration before responsible authorities take action in connection with them;
• to encourage responsible authorities to take actions that promote sustainable development and thereby achieve or maintain a healthy environment and economy;
• to ensure that projects carried out in Canada or on federal lands do not cause significant adverse environmental effects outside the jurisdictions in which the projects are carried out; and
• to ensure that there is an opportunity for public participation in the environmental process.

An environmental assessment is required if a federal authority is required to exercise one or more of the following duties, powers or functions in relation to a project:

• proposes the project;
• grants money to a project;
• grants an interest in land to a project;
• exercises a regulatory duty in relation to a project, such as issuing a permit or licence that is covered under the Law List regulation (SOR/94-636).

The CEAA is based on the self-assessment of projects for environmental effects, by federal departments and agencies. The responsible authority may conduct an environmental assessment in the form of screening, class screening or comprehensive study. Under a screening, a responsible authority has the greatest degree of management and flexibility over the scope and pace of the environmental assessment process. In cases where there is a sound knowledge of the environmental effects and appropriate mitigation measures for a group or class of projects, the responsible authority may be able to use all or part of a class screening report. The majority of projects covered by the CEAA will undergo an environmental assessment through a screening.

Under a comprehensive study, the responsible authority also retains a primary management role over the environmental assessment, but has more obligations than in a screening. These include the need to consider a wider range of factors, submit the comprehensive study report to the Agency for review, take public comments into account and consider the need for a follow-up program.

If the screening or comprehensive study identifies the need for further assessment, the project must move to a public review in the form of either a mediation or panel review.

Canadian Environmental Protection Act

A key aspect of the Canadian Environmental Protection Act, 1999, S.C. 1999, c. 33 (CEPA) is the prevention and management of risks posed by toxic and other harmful substances. CEPA provides for the regulation of federal works, undertakings, and federal lands and waters, where existing legislation administered by the responsible federal department or agency does not provide for the making of regulations to protect the environment. In addition there are provisions for the creation of guidelines and codes for environmentally sound practices and for setting objectives for desirable levels of environmental quality. Either of these provisions could be applied to dredging and disposal activities.

Migratory Birds Convention Act

The purpose of the Migratory Birds Convention Act, 1994, S.C. 1994, c. 22 (MBCA) is to protect and conserve migratory birds, as populations and individual birds, and their nests. The MBCA prohibits the disposal of any substances harmful to migratory birds in any waters or areas frequented by migratory birds (subsection 5.1(1)). In the context of identifying, assessing and managing contaminated sediments in Ontario, the MBCA may be applicable when dealing with the disposal of dredged material.

Fisheries Act

The Fisheries Act, R.S.C. 1985, c. F-14, regulates any activities that can potentially disrupt fish or fish habitat. Two sections of this Act are particularly relevant to dredging projects: Subsection 36(3) regulates the deposition of any substance (which would include contaminated sediment) which is deemed "deleterious" in waters frequented by fish. Section 35 regulates the harmful alteration of fish habitat, including alteration, disruption or destruction of habitat (where habitat is defined as "spawning grounds and nursery, rearing, food supply and migration areas on which fish depend directly or indirectly in order to carry out their life processes").

Navigable Waters Protection Act

The Navigable Waters Protection Act, R.S.C. 1985, c. N-22 (NWPA) prohibits any work on, in, over, under, through or across a navigable waterway. "Work" has been defined to include projects that involve the dumping of fill or the excavation of materials from the bed of navigable waters as well as dredging or disposal operations. An application for approval is required if dredging or disposal operations are undertaken. Prior to granting the approval, Transport Canada reviews the implication of the dredging or disposal operations for potential impact on navigation.

Canada Shipping Act

The Canada Shipping Act, 2001, R.S.C. 2001, c. 26, regulates the discharge from ships (open water disposal) of any pollutant specified in regulations of the Act. Most of these pollutants are those listed in the OMOE guidelines.

Canada Water Act

The Canada Water Act, R.S.C. 1985, c. C-11, provides for management of the water resources of Canada, including research and the planning and implementation of programs relating to the conservation, development and utilization of water resources. Part II of the act specifically deals with water quality management and the pollution of waters.

Great Lakes Water Quality Agreement

The Great Lakes Water Quality Agreement is an agreement between Canada and the United States to restore and enhance the water quality of the Great Lakes. The Agreement, first signed in 1972 and renewed in 1978, expresses the commitment of each country to restore and maintain the chemical, physical and biological integrity of the Great Lakes Basin Ecosystem and includes a number of objectives and guidelines to achieve these goals. In 1987, a Protocol was signed amending the 1978 Agreement. The amendments aimed to strengthen the programs, practices and technology described in the 1978 Agreement and to increase accountability for their implementation.

• Annex 2 of the Agreement relates to Remedial Action Plans and Lakewide Management Plans to control and remediate areas where "beneficial uses" have been impaired and specifies the need for source control programs to reduce loadings of Critical Pollutants.
• Annex 7 of the Agreement specifies that the two governments will develop and implement programs and measures to ensure that dredging activities will have a minimum adverse effect on the environment.
• Annex 12 relates to the presence of persistent toxic compounds and stipulates that the governments shall take all reasonable and practical measures to rehabilitate those areas of the Great Lakes adversely affected by these chemicals.
• Annex 14 of the agreement provides for the governments, in cooperation with State and Provincial Governments to identify the nature and extent of sediment pollution in the Great Lakes System and subsequently develop and evaluate methods to remedy such pollution.

Provincial Legislation and Policies (2.0)

Various Provincial Acts, administered by a number of ministries, may apply to sediment remediation activities.

Environmental Assessment Act

The Environmental Assessment Act, R.S.O. 1990, c. E.18 (EA Act) applies to projects being carried out by the Province, municipalities, or public bodies (for example, Conservation Authorities and the Ontario Realty Commission). The EA Act may also apply to major commercial or business enterprises or activities or proposals, plans or programs, as set out in subsection 3(b) and 3(c) of the EA Act. The EA Act requires that proponents of major projects outline the details of the project and identify how construction, location and ultimate utilization will affect current and future uses of that area. Water quality effects, biological effects, and social and economic factors must be considered. Proponents should consult with the Ministry’s Environmental Assessment and Approvals Branch.

Environmental Protection Act

The Environmental Protection Act, R.S.O. 1990, c. E.19 (EPA) regulates the discharge of contaminants and pollutants (including "spills") into the natural environment. The EPA) aims to protect and conserve the natural environment and to protect human health and plant and animal life from injury and damage and provides for the "repair" of any such damage.

Ontario Water Resources Act

The discharge of any material into water that may impair water quality is prohibited by the authority of the Ontario Water Resources Act, R.S.O. 1990, c. O.40 (OWRA). Subsection 1(3) of the Act sets out a list of what constitutes “deemed impairment”. This includes, but is not limited to, material or derivative which causes or may cause injury to or interference with any living organism that lives in or comes into contact with the water or soil or sediment that is in contact with the water; or which causes or may cause a degradation in the appearance, taste or odour of the water, or which causes or may cause injury to or interference with any living organism as a result of it using or consuming the water, soil or sediment that is in contact with the water or any organism that lives in or comes into contact with the water or soil or sediment that is in contact with the water. The OWRA also contains requirements for obtaining a Permit to Take Water (section 34) or a Sewage Works Approval (section 53) which may be required in certain operations.

Clean Water Act, 2006

The Clean Water Act, 2006 S.O. 2006, c. 22 takes a watershed-based approach to source water protection and addresses all sources of drinking water. Its purpose is to protect existing and future sources of drinking water. Source water protection is the first barrier in a multi-barrier approach to protecting the water in Ontario’s lakes, rivers and underground aquifers, and it complements water treatment by reducing the risk that water gets contaminated in the first place. Where contaminated sediment impacts the quality of source water, the Act and associated regulations may require remediation actions to occur.

Brownfields Amendments (Record of Site Condition Regulation)

Amendments made to Ontario’s EPA and OWRA, among other provincial statutes, in 2003 are commonly referred to as “the Brownfields Amendments”. Several documents are available that provide information on these amendments, including:

• Ontario Regulation 153/04 (as amended) Records of Site Condition – Part XV.1 of the Environmental Protection Act.
• Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (March 9, 2004)
• Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (July 27, 2009)
• Procedures for the Use of Risk Assessment under Part XV.1 of the Environmental Protection Act (October, 2005).

This regulation and supporting documents have replaced the Guidelines for Use at Contaminated Sites in Ontario (MOE, 1997). A key component of the Brownfields Amendments is the introduction of a Record of Site Condition (RSC), which is used to document the assessment and remedial work conducted at a contaminated property. For properties where sediments are a component of the risk assessment, the legislation and applicable regulations should be consulted for details.

Beds of Navigable Waters Act

The requirements of the Beds of Navigable Waters Act, R.S.O. 1990, c. B.4, may impact on projects involving beds of “navigable waters”. While the term “navigable waters” is not defined in this Act, it is a term which has been interpreted by the courts over the years. Title to the beds of navigable waters is restricted through grants by the Lieutenant Governor in Council. Ownership of lands bordering navigable waters does not provide right of use of the beds of those waters.

Public Lands Act

The management, sale and disposition of public lands, which includes the beds of most lakes and rivers as well as seasonally flooded areas, is controlled by the Public Lands Act, R.S.O. 1990, c. P.43. The Ontario Ministry of Natural Resources (OMNR) may define zones as open, deferred or closed for disposition. The Public Lands Act also regulates development, construction, or alteration of any public shorelands, which may apply to remediation projects. All shoreline construction work will require a Work Permit issued by OMNR under this legislation.

Conservation Authorities Act

The administration of the Fill, Construction and Alteration to Waterways Regulations made under Section 28 of the Conservation Authorities Act, R.S.O. 1990, c. C.27 in areas where a Conservation Authority exists may apply to degrading and sediment remediation projects. The regulation is designed to consider the effects of filling, construction of structures, and the modification/ alteration to watercourses in order to prevent flooding and erosion, slope stability and pollution. The intent is to preserve water quality and the conservation of land as well as prevent the creation of new problems or the aggravation of existing problems on and off the site.

Lakes and Rivers Improvement Act

Approval for any work that consists of forwarding, holding back or diverting water (e.g., construction of coffer dams for stream remediation) is required from the OMNR under the Lakes and Rivers Improvement Act, R.S.O. 1990, c. L.3. Furthermore, the deposition of any substance or refuse into a lake or river or on the shore is prohibited by this Act.

Aggregate Resources Act

The Aggregates Resources Act, R.S.O. 1990, c. A. 8. (ARA) is administered by the OMNR and provides a framework for the management of the aggregate resources of Ontario; the control and regulation of aggregate operations on both Crown lands and private lands; the requirement for land rehabilitation; and the minimization of adverse impact on the environment from aggregate operations. Approval for the extraction of aggregates from lands under water is required under the ARA.

Drainage Act

The Drainage Act, R.S.O. 1990 c. D. 17. is administered by the Ontario Ministry of Agriculture, Food and Rural Affairs and provides information on procedures for the construction, improvement and maintenance of drainage works.

Planning Act

The Provincial Wetlands Policy Statement, which was issued under the Planning Act, R.S.O. 1990, c. P13 addresses wetland protection and management within the land use planning process.

Mining Act

All aspects of mining activities within the province are regulated under the Mining Act, R.S.O. 1990, c. M14.

Nutrient Management Act, 2002

The purpose of this Nutrient Management Act, S.O. 2002, c. 4 (NMA) is to provide for the management of materials containing nutrients in ways that will enhance protection of the natural environment and provide a sustainable future for agricultural operations and rural development.

Municipal Legislation and Policies (3.0)

Municipal legislation and policies will affect a project where shoreline or upland disposal is to be used. In these cases, municipal zoning or planning guidelines may have to be considered and taken into account. Since each municipality may have different requirements, the proponent is advised to contact the appropriate municipal office during the initial screening stage of the project. Contacting the municipal office will also permit the proponent to assess the need for public information sessions to facilitate public acceptance of the project.

Sediment Classification and Disposal Options (4.0)

Introduction (4.1)

The need to characterize and classify sediments prior to dredging in order to determine the most environmentally sound disposal options dates back to the 1960’s. The U.S. Federal Water Pollution Control Administration (FWPCA), in Chicago characterized light, moderate and heavy sediment pollution according to ranges of chemical concentrations in l968. The concentration ranges were selected based on observed responses to indigenous benthic population (i.e., abundance and diversity). The FWPCA, Cleveland office, completed a similar exercise in l969, and the two categorizations were combined as the Jensen criteria and adopted by the U.S. EPA in l97l. In the early l970's, the Ontario Water Resources Commission drafted sediment guidelines based on those developed by the U.S. EPA, but modified them to reflect Ontario’s experience with sediment data from Canadian harbours on the Great Lakes. These were revised in 1992 with the publication of new sediment quality guidelines ("Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario") which is now replaced with the ministry publication entitled, “Guidelines for Identifying, Assessing and Managing Contaminated Sediments in Ontario: An Integrated Approach” (OMOE, 2008). The Ontario practice has differed from that of the U.S. in that each dredging project has been and continues to be considered on a case by case basis. Some flexibility is allowed according to local conditions and the nature of the project under evaluation.

As a result of the 2002 Canada-Ontario Agreement (COA) Area of Concern (AOC) Annex, Result 4 “Management Strategies for Contaminated Sediment”, both the OMOE and Environment Canada developed a ‘risk-based decision-making framework’ for the assessment of contaminated sediments. The COA Sediment Decision-Making Framework (COA 2007) provides a consistent and harmonized approach to assess contaminated sediment. The framework provides a decision making framework that considers four lines of evidence simultaneously (sediment chemistry, toxicity, benthos alteration, and biomagnification potential), and identifies the need for management actions based on observed exceedances/effects in the different lines of evidence. The previous MOE 1996 document (An Integrated Approach to the Evaluation and Management of Contaminated Sediments) and the COA sediment assessment framework both consider the same lines of evidence. However, the COA framework provides additional information related to undertaking contaminated sediment evaluation and management work.

Various Ontario Acts and Regulations have an impact on dredged material disposal or use. In the Guidelines, the use of the Ontario Water Resources Actand the Environmental Protection Act, administered by the OMOE, are outlined where appropriate. Compliance with these Guidelines does not exempt a dredging proponent or his agent from other federal, provincial or municipal legislation. However, it is likely that use of the Guidelines will assist the proponent in meeting legislative requirements of other agencies and help expedite proposed projects.

The OMOE strongly recommends that dredging proponents, or their agents, contact and discuss project proposals with OMOE Regional staff, as an initial step, to obtain regulatory and technical advice. This will assist in avoiding potential problems and delays.

Application Requirements (4.2)

To facilitate the review of dredging/disposal applications, the proponent is requested to submit the following:

• A brief outline of the project proposed and the requirements of the project.
• Detailed map of the dredging project site; the map should clearly indicate bathymetry, relation of major landmarks to site, scale (1:500 or 1:1000), direction of north and sample collection sites.
• Description of the nature of the material to be disposed; this should include the results of bulk chemical analyses; results of other tests conducted to further evaluate the materials such as bioassessment testing, geotechnical testing, testing of settleability or leachability etc. This description should also include a discussion of the latest results compared to earlier surveys and an up-dated tabulation of results for the project site.
• A discussion of the proposed disposal alternatives and an evaluation of the disposal mode proposed, including site evaluation, and if containment is proposed, facility design, facility management and facility de-commissioning.
• Generalized map of the disposal area indicating the proposed disposal facility in relation to the project site and the proposed transit routes to the disposal facility.
• If possible, an aerial colour photograph of the project site should be included.

The following example illustrates the information package.

Description of Project

In 1984, Public Works Canada proposed maintenance dredging of portions of the Burlington Ship Canal from Hamilton Harbour into Lake Ontario, specifically to remove accumulated sand. Two areas were to be dredged comprising 25,000 m³ in the north section and 2,000 m³ in the south section of the canal.

It was determined that Trans Northern Pipelines owned a pipeline crossing the mouth of the canal at the lakeward end which might be impacted by the dredging. Its elevation was checked in the field and was found to be safely below the limit of dredging.

Discussion of Testing for this Project

Three sediment samples were collected for analysis: one from the north section, one from the south section and one control from Hamilton Harbour. The south sample contained 100 ng/g of PCBs (compared to Lowest Effect Level of Provincial Sediment Quality Guidelines of 70 ng/g). Other parameters and locations were within the guidelines.

OMOE requested further sampling to delineate the extent of the contamination: five samples from the north section and three from the south. PCB contamination was verified in the south section at a different location than had been sampled the first time. Therefore, it was decided that the entire 2,000 m³ of material would be disposed of in the Hamilton Harbour Commission’s confined disposal facility. Contamination (126 ng/g of PCB at a location close to where 40 ng/g of PCB had been found the first time) was determined in one sample from the north section.

Disposal Alternatives

It was decided to isolate an area 20 metres east and west of the sampling point and extending the full width of the dredging area from north to south for disposal in the confined disposal facility (CDF) located inside Hamilton Harbour. The remainder of the dredged material, which met OMOE guidelines for open water disposal, was barged to an established off-shore disposal site, about 1 km southeast of the canal in Lake Ontario. This location had been previously designated for uncontaminated dredged material disposal. The City of Hamilton water treatment plant intake was 4 km from the disposal site, therefore no impact on the water supply was anticipated. Routine monitoring of turbidity levels at the intake revealed no impact of the spoils disposal.

Monitoring Program

The OMOE chose to monitor the dredging activities associated with the Burlington Canal because of the potential impacts to water quality uses and aquatic biota. Open water disposal operations may result in dispersion and movement of sediment related contaminants and/or disruption of the bottom habitat at the disposal site.

The monitoring program had several sampling components:

• pre and post disposal surficial sediment samples.
• suspended sediment sampling with both sediment traps and centrifuging of surficial water.
• visual description both aerial and diver.
• transmissometer measurements (refer to Figures 4.1 and 4.2).

Recommendations

1. Study has shown that there is a need for site specific monitoring. Each dredging project and disposal technique should be monitored because certain factors (i.e. prevalent wind direction, dredging location embayment vs. open lake, navigational activities etc.) influencing each site may vary.
2. When the chemical and physical characteristics of the 'newly' exposed si endiment is unknown, coring for sediment should be employed. The 'newly' exposed sediment may be contaminated and perhaps may be a potential environmental problem.
3. Silt curtains or a similar contaminant device may be required at a dredge site to control movement of suspended material. Plumes were observed at the dredging site.
4. Biological studies (e.g., community structure analysis) may be required to assess the potential environmental impacts to aquatic biota. Sediment bioassays may also be required to assess the toxicity and bioaccumulation of contaminants in sediments.

Dredged Material Classification Process For Disposal (4.3)

Application (4.3.1)

This classification process differentiates dredged material on the basis of chemical and physical characteristics. The dredged material management options include: open water disposal, disposal on land and confined disposal.

The classification process applies to dredged material originating from commercial, industrial or public sector undertakings with the exception of agricultural drainage activities managed by Ontario municipalities under the Drainage Act, and resource recovery activities under the Aggregate Resources Act administered by the Ontario Ministry of Natural Resources. The disposal of dredged material from agricultural drainage activities is governed by guidelines established by the Ontario Ministry of Agriculture, Food and Rural Affairs.

Depending on the magnitude and location of small dredging projects of a non- commercial, non-industrial or non-public sector nature (e.g., cottage owners), they may be exempt from this classification process. Such exemptions would be made at the discretion of the appropriate OMOE staff. Dredged material from these exempted undertakings should be handled in the following manner:

• disposed of on-land, on-site, above the high water mark, and
• stabilized as soon as possible to prevent its re-entry into the waterbody.

Classification Options (4.3.2)

The dredged material, depending upon its chemical and physical characteristics relative to the parameters presented in Appendix A, will be classified in one of the following categories:

1. suitable for open water disposal;
2. suitable for disposal on land
3. contaminated material requiring disposal at a certified confined disposal facility (dewatering permitted);
4. severely contaminated material requiring specialized disposal at a certified confined disposal facility (with no dewatering)

Note: The following documents and references should be considered when determining the suitability of Disposal alternatives B through D:

• Ontario Regulation 153/04 (as amended) Records of Site Condition – Part XV.1 of the Environmental Protection Act.
• Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (March 9, 2004). [Note: these standards are no longer in effect after July 1 2011]
• Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (July 27, 2009).
• Procedures for the Use of Risk Assessment under Part XV.1 of the Environmental Protection Act (October, 2005).
• Guidelines for the Utilization of Biosolids and Other Wastes on Agricultural Land. March 1996. Ontario Ministry of Agriculture and Food, Ontario Ministry of Environment.
• Best Management Practices – Application of Municipal Sewage Biosolids to Cropland in 2010 Ontario Ministry of Agriculture, Food & Rural Affairs, Ontario Federation of Agriculture,
• O. Reg. 267/03 as amended under the Nutrient Management Act. See the e-Laws website.

Selection of the disposal alternative is made on a case-by-case basis. The classification procedure is briefly described in the following section.

Classification Process (4.3.3)

In this section, the disposal alternatives are discussed in the following terms:

• evaluation process,
• guidelines for the various options, and
• required analyses for the options.

OMOE concurrence and/or approval is required for each of these options. Compliance with these requirements does not exempt a dredging proponent or his agent from other provincial or federal legislation.

Analysis and evaluations, in addition to those outlined below, may be requested at the discretion of OMOE staff, after initial discussions with the proponent. These additional requirements may reflect the results of ongoing investigations in an area (e.g., the St. Clair River), where constituents not listed in Tables 1, 2a, or 2b of Appendix A have been identified in concentrations deemed hazardous or potentially hazardous. The evaluation process may require the use of bioassessment procedures. Information in this regard can be obtained by contacting OMOE.

Separation of dredged materials identified as "contaminated""" from "uncontaminated" areas will be accepted if the proponent can demonstrate to the satisfaction of OMOE that:

• there are distinct areas or layers of sediments of different quality, and
• the necessary equipment and expertise are available to undertake the dredging operations.

Open Water Disposal (including beach nourishment) (4.3.3.1)

The chemical quality of the dredged material is compared to the Provincial Sediment Quality Guidelines (Appendix A). The Sediment Quality Guidelines also require determination of the chemical quality of the sediments in the proposed disposal area. Evaluation of the suitability of disposal of dredged material depends on both the chemical quality of the dredged material and the existing chemical quality of the sediments at the disposal site. The evaluation procedure is described in detail in Appendix A. Selection of a disposal site is also governed by other considerations which are detailed in Chapter 5.0.

For dredged material with contaminants other than those in Tables 1, 2a, or 2b in Appendix A, the required method of disposal shall be determined by OMOE.

Confined Disposal (4.3.3.2)

If the quality of the dredged material exceeds the relevant guideline levels of the Provincial Sediment Quality Guidelines as described in Appendix A, then the material is not suitable for open water disposal. Where dredged material is not suitable for open water disposal, the material is to be disposed of in a Confined Disposal Facility under the terms and conditions as described in Section 6 of this report, or in a suitable upland disposal site as determined in documents mentioned in section 4.3.2 of this document.

Unconfined Open Water Disposal (5.0)

Introduction (5.1)

Environmental, engineering and economic factors must be considered in the selection of an open water disposal site. To properly evaluate all potential sites, an impact matrix should be constructed which lists all of the criteria given in the following discussions. Where possible, all relevant data should be collected and collated, identifying areas where additional data collection may be necessary. Once sites have been evaluated on the basis of environmental impacts, the engineering and economics of haulage should be considered. The final "short-list" of sites should be discussed with staff from the OMOE Regional Office before data collection begins.

Site Selection Criteria (5.2)

The site selection criteria were developed by the Dredging Sub-Committee of the International Joint Commission (IJC) and are adapted with minor changes from their l983 report (IJC, l983). Additional information is available through the IJC website or through the Great Lakes Commission website.

Open water disposal sites should be located so as to avoid adverse impacts on:

• commerce and transportation, including commercial shipping, commercial fishing, pipeline and cable crossings and mineral and aggregate extraction;
• water intakes and outfalls;
• recreational uses and aesthetic values of the area;
• bottom topography so as not to adversely impact water circulation, current patterns, water level fluctuations, temperature regime, erosion and accretion patterns, and wave climate;
• sites of natural, cultural, archaeological, historical and research significance;
• sanctuaries and refuges, breeding, spawning, nursery and feeding habitats, and passage areas for fish; and
• species of special interest such as threatened and endangered species.

In addition, open water disposal sites should:

• be compatible with the physical and chemical characteristics of the dredged material to the maximum extent practicable;
• utilize the smallest practicable disposal area;
• locate where current and past dredged material disposal has occurred, if these sites meet the other guidelines; and
• be selected to minimize the dispersal, erosion and slumping of the material so that only the smallest practicable part of the waterbody will be affected. In applying the above-mentioned guidelines, the following considerations need to be addressed.

Impact on Various Commercial Activities (5.2.1)

The sites and the transit routes from the project area should be selected so as to minimize interference with navigation, commercial fishing, submerged pipelines or cables, and sand, gravel or mineral extractions.

Information regarding the navigation channels in the Great Lakes is available from the Canadian Hydrographic Service website and the U.S. National Oceanic and Atmospheric Administration website. Except for long, buoyed navigation channels extending several kilometres from shore, open lake disposal sites have typically been located 1 to 3 km away from navigation channels. It is believed that this distance is sufficient to prevent potential adverse impacts to the navigation channels. At locations where open lake disposal sites may be near commercial navigation sailing courses, minimum depths at Low Water Datum should be maintained, where feasible, in order to avoid grounding of vessels.

The minimum depth needed at any specific area should be at least equal to the greatest project depth which is charted at nearby navigation channels and harbours. The locations of other installations in the lake bottom, such as cables, pipelines, well-heads and commercial fishing net stakes, are identified on the nautical charts. In those cases where it may not be possible to maintain a minimum depth, open lake disposal areas should be registered with the Canadian Coast Guard, so that notice to mariners can be made. Published information is not generally available regarding the locations of sand, gravel or mineral resources and extraction activities in many areas of the Great Lakes. The current national and local permitting processes for disposal activities consider potential conflicts between open lake dredged material disposal and sand, gravel or mineral extraction.

Water Intakes and Outfalls (5.2.2)

Use of the open water disposal site should not interfere with municipal, industrial or other types of water intakes and outfalls.

Deposition of dredged material close to a water intake may increase the suspended solids load to a water treatment facility resulting in additional filtration requirements and costs. In some cases, material deposited in the vicinity of a water intake may not have an immediate effect, since most disposals occur during calm periods. Such material, however, can be resuspended during storms and affect the quality of water entering the intake. Mounds of material adjacent to an intake may also affect the proper functioning of the intake port as a result of physical obstruction to the port. Such mounds of materials can also attract certain species of fish which could be drawn into an intake.

Disposal of dredged material close to an effluent outfall may reduce the design dispersion characteristics of the outfall. Thermal, sewage and stormwater effluents require adequate mixing and transport via currents to prevent local water quality degradation. Mounds of dredged material could impede water movement in the vicinity of outfalls. Deposition of material resulting in blockage of a diffuser port on multiport outfalls may result in hydraulic overloading in the outfall. This would result in the diffuser caps being lifted off causing pressure drops at the remaining ports. Disposal in the vicinity of an outfall must be well outside of a safe zone designated by appropriate regulatory agencies and the agency and operator responsible for the outfall.

Recreational Uses and Aesthetic Values of the Area (5.2.3)

An open water disposal site should be removed from areas of recognized recreational value such as beaches and wildlife areas. Disposal procedures should be designed so as to prevent or minimize any potential damage to the aesthetically pleasing features of the open water site, especially in regards to water quality. In some instances, clean dredged material may be considered suitable for beach nourishment. Disposal operations should be timed so as not to interfere with the peak recreational period.

Bottom Topography (5.2.4)

Bottom topography influences the current patterns and water circulation and, therefore, plays a critical role in the ecology of lakes. Current patterns and water circulation (i.e., physical movement of water in the aquatic system) act to transport sediment and dilute dissolved and suspended chemical constituents. They also transport food and nutrients for aquatic organisms, provide directional orientation to migrating species and moderate extremes in temperature variations. Normal water fluctuations in a body of water affect water depth, water quality and are critical during spawning and feeding season. Prevalent accretion and erosion patterns in an area determine the bottom movement of material. Similarly, alterations in the wave climate can severely affect or destroy populations of aquatic animals and vegetation, modify habitats, reduce food supplies and change erosion patterns.

The dredged material should be deposited in a layer of suitable thickness at the disposal site to maintain natural bottom contours and elevation. In locations where mounding is an acceptable and ecologically desirable alternative, the shape and orientation of the mounds should be such that they will have a minimal impact on the prevailing current pattern and water circulation. The height and shape of mounds should be such as not to change existing depths and available fetches to adversely alter the wave climate of the area. The disposal of the dredged material should not result in enclosed areas of stagnant water, especially during low water cycles.

Sites of Historical Significance (5.2.5)

Open lake dredged material disposal sites should be located away from areas of historical significance. Areas which are designated for their natural, cultural, archaeological, historical or scientific significance should be preserved in their existing state and managed so as to ensure continued access.

Natural areas include important examples of natural history in the form of plant and animal communities, landforms and geological features. Natural areas are tracts of water so little modified by man’s activity or sufficiently recovered that they contain native plant and animal communities believed to be representative of the pre-settlement landscape.

Historic and cultural resources include sites, areas, structures and objects of significance in history, architecture, archaeology or culture, e.g., sunken ships at the bottom of the Great Lakes. Sites, such as Fathom Five Underwater Park near Tobermory in Georgian Bay, are valuable because in their natural and undisturbed state they contain useful scientific information. In many areas, known historical sites are catalogued.

Sanctuaries and Refuges, Breeding, Spawning, Nursery and Feeding Habitats, and Passage Areas of Biota (5.2.6)

The disposal of dredged material should not damage or destroy wetlands, sanctuaries, refuges or other areas designated and managed for the preservation of fish and wildlife. Improper disposal can reduce suitable habitats for many species of fish, wildlife and other biota, and interfere with spawning, migration or other life stage activities. Habitats can also be damaged by changes in water levels or circulation and by smothering. Appropriate surveys of the area should be conducted prior to dredged material disposal in such areas.

Applicable listings of species whose continued existence is considered to be threatened (i.e., those species designated as "rare and protected", "endangered", etc.) must be considered when selecting a disposal site. The disposal site must not adversely impact or interfere with the continued survival, reproduction or movement of such species or with management efforts to protect and rehabilitate such species. In addition, the disposal site must not adversely impact on or interfere with management plans or efforts for other species of special interest, such as those designated for intensive management or for introduction into the Great Lakes. Included in these considerations is protection of the forage base upon which these species are dependent.

Sediment Compatibility with Substrate at Disposal Site (5.2.7)

Compatibility of the dredged material with the substrate at the disposal site is desirable in order to maintain the physical, chemical and biological state of the site. Some allowance for temporary changes in the substrate immediately following disposal can be made, but the major objective should be either an improvement or a quick return to the natural substrate type at the disposal site. The principle of "sediment matching" has been incorporated into the chemical evaluation procedure described in Appendix A.

"Sediment matching" has been used to minimize the impact of dredged material disposal on biota. This involves finding an area having substrate similar to that at the site to be dredged and disposing of the dredged material at that location. Sediment matching accomplishes two things:

1. It reduces the time required for re-colonization by biota because organisms from nearby areas should be adapted to conditions found in the dredged material; and
2. It minimizes the time required for the establishment of a 'stable' biological community. The more similar the dredged material is to the surrounding area, the less time will be required to reach equilibrium with respect to both chemical and physical characteristics.

For the above two reasons, sediment matching should be employed where possible. However, there are circumstances that preclude the use of sediment matching. These include availability of disposal site substrate similar to the substrate to be dredged, economics and the need or desire on part of resource managers to create a new habitat type in an area.

If sediment matching is not practical, then consideration must be given to the type of sediment to be dredged and its compatibility with substrate at the disposal site. From a biological (habitat) perspective, sediment can be conveniently divided into three types: coarse - gravel, cobbles, boulders (with some fines); medium - sand with some fines; fine - silt and clay. Each of these has characteristic properties that make it valuable to different components of the biological community.

Coarse-grained sediments provide valuable habitat for many species of invertebrates, including those that are considered to be valuable as fish food, and generally provide good habitat for fish spawning, rearing and feeding.

Medium-grained sediments provide poor substrate for invertebrates, except for the few species that are capable of living in and on this unstable, nutrient-poor medium. Sand should not be deposited on another substrate type unless absolutely necessary. In cases where sand is deposited in deep water over fine sediment, there may be a long period of time over which the substrate will be altered unless the sand passes completely through the softer material.

Fine-grained sediments provide good substrate for benthic invertebrates, but are generally poor for fish spawning. If macrophyte growth occurs, then excellent habitat for spawning, rearing and foraging is provided for some species. Fine sediments, however, are usually nutrient-rich and can cause or aggravate enrichment problems.

Minimizing the Size of Disposal Area (5.2.8)

Use of a site for dredged material disposal will have some impacts. In order to minimize the area affected, the size of the disposal area used should be kept to a minimum. Designation of the site must take into account that the area on the bottom will be a much larger impact zone than on the water surface. The disposal area must be easy to locate by the ship or barge operator, so the material can be placed inside the designated boundaries of the site. To facilitate this, the disposal area should be clearly marked. Accurate site location is particularly important if the deposited material is to be "capped" with other materials (to better match substrate, enhance habitat or help seal off pollutants). The capping material must be accurately placed over the previously deposited material.

Use of Current and Past Disposal Sites (5.2.9)

Current and past open water disposal sites may have been chosen after consideration of factors such as distance from dredging site, proximity to navigation channels, etc. and may already be in compliance with these guidelines. The use of existing sites is preferred for localizing impacts of disposal. If there are some unavoidable adverse impacts from disposal, it would be preferable to continue to use existing sites where degradation has already occurred rather than affecting other areas. Since these sites have been used in the past, surveys can be done to determine actual impacts from their use by comparison with surrounding lake bottom outside the disposal area.

Minimizing Dispersal, Erosion and Slumping of Dredged Material at the Disposal Site (5.2.10)

Retention of dredged materials at disposal sites can be fostered by proper site selection, disposal methods and dredged material stabilization. Disposal sites should, therefore, have the following characteristics:

• particle sizes as fine as or finer than the dredged materials;
• bottom slopes should not be steep;
• sites should not be adjacent to channels; and
• sites should have a low hydraulic energy (both bottom currents and storm erosion).

It is recommended to use disposal sites which have shown minimum dispersal, slumping or erosion of dredged materials in the past.

Disposal methods which would aid in dredged material retention are:

• accurate placement of dredged materials; and
• timing of disposal so that water levels and currents would permit maximum settling and compaction.

Retention of dredged materials on-site can be fostered by:

• establishing aquatic or semi-aquatic vegetation as soon as possible where this is feasible.

Site Surveys (5.3)

Components which are undertaken in site surveys should assist in the choice of the actual site and augment long-term monitoring by providing "pre-activity" data. Site specific factors to be measured include:

Bottom Erodability

• select an area of low hydraulic energy with similar particle size as the dredged sediments;
• obtain information on bottom currents;
• measure the particle size of the site sediments to obtain an estimate of bottom currents in the area; and
• use wave and storm hindcasting models to predict the effect of major storms on the hydraulic energy of the site

Biological Community

• determine the speciation and biomass of the benthic community;
• determine the commercial and sport fishing in the area; and
• determine suitable biota (benthic organisms) which could be used in subsequent monitoring of bioaccumulation of contaminants.

Because of the cost of such data collection, it is advisable to make use of all available historical data supplemented by either diver or remote- operated vehicle observations. Once a site is chosen, more detailed information can be collected. In addition, the suspended solids (throughout water column) in the area should be characterized for quantity and contaminant concentrations. This data will provide a "pre-use" data base. Monitoring over a period of time may prove useful to allow for natural fluctuations in concentrations of contaminants. Data collection sites should be chosen on the basis of operational monitoring requirements.

Confined Disposal Facilities (6.0)

Purpose (6.1)

Confined disposal facilities (CDFs) are appropriate when it is deemed necessary to isolate contaminated dredged materials from the environment. To fulfill its role, a CDF must be designed and managed to retain the contaminated dredged materials without impairing the quality of the adjacent waters, and without creating subsequent contaminant pathways (e.g., dust, vegetative uptake, erosion). Because a CDF is a long-term structure it should be sited with a view to compatibility with existing and proposed land and water uses. Additional information is available in the Ministry document entitled, “Fill Quality Guide and Good Management Practices for Shore Infilling in Ontario” (MOE, 2011).

Under Water Containment (6.2)

Traditionally, contaminated dredged materials have been placed in shoreline or upland containment facilities to remove and isolate the materials from the aquatic environment. However, the higher cost of on-land disposal, coupled with the significant environmental impacts, have led to the development of underwater "confinement" or "capping". This procedure is not a commonly used technique in Ontario but has been used in other areas such as the New York Bight.

There are three main concerns with open water disposal of contaminated sediments:

• erosion and off-site transport of the fine-grained sediments with which much of the contaminants are associated;
• interaction of colonizing benthos or bottom-feeding fish; and
• long-term transfer of contaminants into the overlying water column.

To overcome these concerns, the "borrow and fill" and "capping" techniques have been developed. In the borrow and fill technique, a large pit is excavated and the excavation material placed to one side for later use. The contaminated dredged material is placed in the pit and the excavated material used as cover. This offers the advantage of covering the site with sediment similar to the adjacent area and a cost savings by not having to transport cover material to the site. In the capping technique, the dredged material is placed at the disposal site and covered with a thin layer of uncontaminated material which will not be eroded from the site. In the past, this material was medium- coarse sand. A drawback to capping is the need to dredge sediment from another area and transport it to the disposal site. It is not recommended to use sand if the material being covered has a different texture, i.e., finer to prevent the cap from penetrating the less dense material. In these instances, fine, clean sediment should be used as the capping substrate. Careful placement has been a problem for projects attempted in Atlantic Canada. Typically, a cover volume of three to five times the volume of dredged sediments has been required to provide a cover of at least one metre (Bokuniewicz, 1981a,b; 1982).

Care has to be taken that the cover material does not displace nor inter-mix with the dredged sediments, and that the cap adequately covers all of the dredged materials.

Design and Operation Considerations of Shoreline and Upland CDFs (6.3)

Several factors must be taken into consideration in the design and operation of shoreline and upland facilities. These include:

• Site Designation:
  • land ownership
  • municipal planning/zoning restrictions
  • public perception
  • adjacent land uses and restrictions
  • water lots and riparian rights
  • site accessibility
  • interference with longshore transport or susceptibility to erosion
  • geotechnical properties of site soil
  • geology and hydrogeology of site
  • capacity for enlargement
• Facility Design:
  • restrictions imposed by site designation review
  • physical and chemical nature of materials
  • method of material entry
  • allowance for over-dredging and volume increase due to entrained water
  • effluent quality requirements
  • drainage to receiving waters
  • long-term capacity requirements
• Facility Usage:
  • restrictions determined by site designation review
  • interference with normal navigational or recreational uses of waterway by disposal
  • transportation
  • maintenance of site integrity (structural)
  • control of site accessibility
  • maintenance of effluent requirements
• Facility De-Commissioning:
  • isolation of dredged materials
  • maintenance of material integrity
  • restrictions on site accessibility
  • restrictions on site usage
  • long-term monitoring requirements

Site Designation (6.3.1)

It is preferable to designate a site on property controlled by either the project proponent (e.g., Public Works and Government Services Canada) or the project initiator (e.g., a harbour commission). However, consideration must be given to adjacent property ownership and uses. This may lead to a requirement for creation of a buffer zone. There may be specific municipal zoning or planning strategies controlling the use of the area, such as designation of the property under a holding zone for future recreational park or waterfront development. An important restriction on shoreline CDFs is waterlot and riparian rights. Siting of a CDF may deprive an adjacent landowner from access to waterborne transportation or the use of a waterway for cooling waters or effluent pipe right-of-way. Consultation with municipal planning authorities and local property owners should be considered at this stage.

Site accessibility is very important in site designation for CDFs. The transportation of dredged material can present a hindrance to other water uses: navigational or recreational use of the waterway can be hindered by barge traffic or the hydraulic pipeline on a suction dredge; special handling facilities may have to be constructed on the shoreline to accommodate double-handling; truck traffic to an upland facility may be restricted to select times, select routes and may require specially equipped trucks; hydraulic pipelines on a suction dredge may require special rights-of-way.

Engineering considerations in site evaluation must include the geotechnical, geological and hydrogeological characteristics of the site. Consideration must be given to the ability of the site to support the weight of the berms and the dredged materials without slumping or ground-faulting. Removal of soft underlying layers to stabilize berm foundations or the installation of special geotextiles may be required. Geological factors include depth of overburden, nature of overburden and underlying rock type and structure. Because many areas depend on groundwater for potable water supply, the hydrogeological characteristics of the site have to be reviewed and may lead to a requirement for a special liner. A special requirement of shoreline facility designation is interference with longshore transport and the susceptibility to erosion or over-topping. Evaluation of erosion and the use of protective armour stone may be required. The overall cost estimates for the facility should also include availability and transportation costs of material for berm construction.

Proper review of site designation factors can be very complicated and time-consuming. It may be advisable to construct a matrix chart in order to ensure that all factors are adequately considered and the cost components of each factor summarized. This way a meaningful comparison of factors and associated costs for each site may be made.

Facility Design (6.3.2)

The design may have to be tailored to specific restrictions developed under the site designation stage; however, the main criteria will be the physical and chemical nature of the material to be confined. The design factor will include any regulatory restrictions on permitting dewatering and the quality of the dewatered effluent. The nature of the material may be such that special liners, increased control of the permeability of the berms, addition of settling agents and special effluent control mechanisms may be required.

If dewatering is permitted, then the CDF should be designed to minimize the loss of fine- grained particulate matter with which contaminants are most likely associated. The objective is to reduce the horizontal velocity of a sediment particle relative to its vertical sedimentation velocity. Sedimentation of the fine-grained particulate matter can be accomplished by:

• increasing the distance between the inlet and the effluent outlet;
• decreasing the horizontal velocity of the water between the inlet and the outlet (i.e. maximize travel time between inlet and outlet); and
• adding chemical(s) to increase the sedimentation rate.

Specific information of designs to promote settling can be found in Palermo et al.(l978); information on the addition of agents to promote flocculation and sedimentation can be found in Wang and Chen (l977) and Schroeder (l983).

The design must also consider the method by which the material is dredged and transported to the site. Hydraulic dredging typically yields a slurry of 3 to 20% solids content. The extra water must either be allowed to be drained off or the facility increased in size. The physical nature of the material will also be altered during the hydraulic dredging. This could lead to a subsequent problem of a very slow rate of settling of the dredged material in the containment facility.

The method of placing of material into the CDF can be critical in maintaining a reasonable rate of sedimentation inside the facility. The hydraulic pipeline should have a deflector plate on the end to reduce the input velocity and to prevent erosion of the inner walls of the berms. Log booms may also be required near the entry point to further reduce horizontal velocity and to retain any surface froth and scum.

Facility capacity should take into consideration:

• potential over-dredging;
• extra volume requirements created by water entrained by the hydraulic dredging process;
• effluent specifications; and
• long-term requirements for dredging at the project site.

The stated purpose of placing the dredged material in the CDF was to prevent dispersal of contaminated sediment subsequent to the dredging operation. Because contaminants are preferentially associated with fine-grained sediments, most effluent controls will be based on a control of the suspended sediments content of the effluent. Design of the effluent control mechanisms to maximize the retention of suspended solids and to minimize the effort to accomplish this task is one of the most important components of the facility design. Effluent controls typically consist of weirs which are sections of the berm at lower elevation and are covered with a coarse gravel (to prevent erosion). More elaborate controls can consist of special geotextiles or semi-permeable berms, flow control valves or a series of overflow pipes. Guidelines regulating the quality of the effluent may be a combination of province-wide regulations and the quality of the receiving waters.

Drainage of the dewatering effluent from a shoreline CDF is relatively simple, taking into account potential for erosion of undermining of the effluent structure. Drainage from an upland site must take into consideration the stream flow characteristics of the receiving stream so as to minimize the physical impact on that receiving waterbody.

Facility Usage (6.3.3)

Restrictions on the operation of the facility can be created by other users of the waterway affecting both the dredging operation and the transportation of dredged materials to the CDF. These users can include both commercial and recreational craft. Other restrictions can be caused by commercial fishing operations or seasonal limitations to protect fish migrations or larval development.

Maintenance of site integrity should be relatively simple if careful planning and design is incorporated into the site designation and facility design stages. Contingency plans may have to be developed to accommodate berm slumping (due to site degradation) or failure to meet dewatering effluent requirements. Site integrity can also be maintained by careful regulation of other users (i.e., other dredged material disposal operations) of the site, as well as regulation of public access to the site to reduce liability due to accidents and the disposal of garbage and other miscellaneous wastes. If the facility will be actively used over a number of years, control of re-vegetation and use of the facilities by migratory birds and other wildlife may have to be instituted.

Facility De-Commissioning (6.3.4)

The first stage in de-commissioning is to ensure the long-term encapsulation of the dredged materials. This may entail the covering of the site with a special membrane or clay liner or simple in-filling to "bury" the materials. This over-burden will also serve to increase the geotechnical strength of the site, thereby increasing its potential subsequent use. A good example is the Pier 26 development in Hamilton. There, the dewatered sediment has been covered with layers of slag waste from an adjacent steelmaking facility which serves to both dispose of the slag and to provide a cover for the CDF.

Long-term monitoring is often required as many of the potential chemical processes within the dredged sediments occur over long periods of time. Specific discussion on the chemical reactions and potential leaching that can occur can be found in Gambrell et al.(1978) and Chen et al. (1978). Such monitoring will also assess the potential for infiltration from surface or groundwaters. Provision for monitoring wells and drainage systems may be required.

The CDF can be designed and operated to facilitate other uses after de-commissioning. Detailed discussion of re-use management can be found in Montgomery et al. (1978).

These uses could include industrial land, land to augment port facilities (e.g., storage of containers), or recreational lands. Each subsequent use must be evaluated for its own special requirements ranging from geotechnical properties of the site through to the potential implications for long-term leaching of chemical constituents from the site. Vegetation of the de-commissioned site may be desirable but must be controlled to inhibit the uptake of contaminants into the vegetation (Folsom et al. 1981). This particularly applies to agricultural use of the site. The overall cost/benefit evaluation of a dredging project can include subsequent use of a CDF.

CDF Examples (6.4)

Since the early 1970's the shoreline or upland CDF option has been the most commonly used mode of disposal for dredged materials in the Great Lakes both in Canada and the United States. The primary purpose was to restrict the dispersion of contaminated sediments which was believed to be occurring from open water sites and to remove contaminated sediments from the Great Lakes thereby assisting in the improvement of water quality.

Detailed information on specific CDFs can be obtained from the U.S. Army Corps of Engineers website. Additional detailed information on the design and management of confined disposal facilities can be found in Palermo et al. (l978), Hunt et al. (l978), Walsh and Malkasian (l978) and subsequent unpublished reports by the U.S. Army Corps of Engineers.

References

Bokuniewicz, H.J., R. Cerrato, and A. Mitchell. 1981a. Criteria for caps on subaqueous sites. Proceed seminar "Dredging and Related Problems in the Mid-Atlantic Region";. Oct., 1981. Baltimore Maryland (272-278).

Bokuniewicz, H.J. and J.T. Liu. 1981b. Stability of Layered dredged sediments at subaqueous sites. Proceed. Oceans 1981 Conf. (752-754).

Bokuniewicz, H.J. 1982. Burial of Dredged Sediment Beneath the Floor of New York Harbour. Proceed. Oceans September 1982 Conf., Washington (1016-1020).

Chen, K.Y., J.L. Mang, B. Eichenberger and R.E. Hoeppel. 1978. Confined Disposal Area Effluent and Leachate Control (Laboratory and Field Investigations). Dredged Material Res. Pgm. Tech. Rept. DS-78-7. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Miss.

Folsom, B.L., Jr., C.R. Lee, and D.J. Bates. 1981. Influence of Disposal Environment on Availability and Plant Uptake of Heavy Metals in Dredged Material. Tech. Rept. EL-81-12. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Miss.

Gambrell, R.P., Khalid, R.A. and W.H. Patrick, Jr. 1978. Disposal Alternatives for Contaminated Dredged Material as a Management Tool to Minimize Adverse Environmental Effects. Dredged Material Res. Pgm. Tech. Rept. DS-78-8. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Miss.

Hunt, L.J., M.C. Landin, A.W. Ford and B.R. Wells. 1978. Upland Habitat Development with Dredged Material: Engineering and Plant Propagation. Dredged Material Res. Pgm. Tech. Rept. Ds-78-17. U.S. Army Corps Engineers, Waterways Experiment Station, Vicksburg, Miss. (160 pg.)

IJC (International Joint Commission). 1983. Report on Great Lakes Water Quality, Appendix. Report of the Dredging Subcommittee to the Water Quality Programs Committee of the Great Lakes Water Quality Board. August 1983.

Montgomery, R.L., A.W. Ford, M.E. Poindexter and M.K. Bartos. 1978. Guidelines for dredged material disposal area reuse management. Dredged Material Res. Pgm. Tech. Rept. DS-78-12. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Miss.

OMAF/OMOE.. 1996 Guidelines for the Utilization of Biosolids and Other Wastes on Agricultural Land. Ontario Ministry of Agriculture and Food, Ontario Ministry of Environment

OMOE.. 1994. Water Management, goals, policies, objectives and implementation procedures of the Ministry of Environment. Ontario Ministry of Environment, Toronto, Ontario.

OMOE. 1997. Guidelines for Use at Contaminated Sites in Ontario. Ontario Ministry of the Environment, Toronto, Ontario

OMOE. 2004. Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (March 9, 2004). Ontario Ministry of the Environment, Toronto. Ontario

OMOE. 2008. Guidelines for Identifying, Assessing and Managing Contaminated Sediments in Ontario: An Integrated Approach. Ontario Ministry of the Environment, Toronto, Ontario

OMOE. 2009. Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act (July 27, 2009). Ontario Ministry of the Environment, Toronto. Ontario

OMOE. 2011. Fill Quality Guide and Good Management Practices for Shore Infilling in Ontario. Ontario Ministry of the Environment, Toronto, Ontario

Palermo, M.R., R.L. Montgomery and M.E. Poindexter. 1978. Guidelines for Designing, Operating and Managing Dredged Material Containment Areas. Dredged Material Res. Pgm. Tech. Rept. DS-78-10.

Persaud, D. and W.D. Wilkins. 1995. Evaluating Construction Activities Impacting on Water Resources. Ontario Ministry of Environment.

Persaud, D., R. Jaagumagi and A. Hayton. 1992. Guidelines for the Protection and Management of Aquatic Sediment Quality in Ontario. OMOE, Toronto. 30pp.

Schroeder, P.R. 1983. Chemical Clarification Methods for Confined Dredged Material Disposal. Tech. Rept. D-83-2. U.S. Army Corps Engineers, Waterways Experiment Station, Vicksburg, Miss. (147 pg.)

Walsh, M.R. and M.D. Malkasian. 1978. Productive Land Use of Dredged Material Containment Areas: Planning and Implementation Considerations. Dredged material Res. Pgm. Tech. Rept. DS-78-20. U.S. Army Corps Engineers, Waterways Experiment Station, Vicksburg, Miss. (112 pg.)

Wang, C.C. and Chen, K.Y. 1977. Laboratory Study of Chemical Coagulation as a means of treatment for dredged material. Dredged Material Res. Pgm. Tech. Rept. D-77-39. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, Miss.

Appendix A

Provincial Sediment Quality Guidelines

(Reprinted from Guidelines for Identifying, Assessing and Managing Contaminated Sediments in Ontario: An Integrated Approach, 2008)

The purpose of the Provincial Sediment Quality Guidelines is to protect the aquatic environment by setting safe levels for metals, nutrients (substances which promote the growth of algae) and organic compounds.

The guidelines establish three levels of effect - No Effect Level, Lowest Effect Level and Severe Effect level. The Lowest Effect Level and Severe Effect Level are based on the long-term effects which the contaminants may have on the sediment-dwelling organisms. The No Effect Level is based on levels of chemicals which are so low that significant amounts of contaminants are not expected to be passed through the food chain.

The three levels of effect are:

The No Effect Level: The No Effect Level (NEL) indicates a concentration of a chemical in the sediment that does not affect fish or sediment-dwelling organisms. At this level negligible transfer of chemicals through the food chain and no effect on water quality is expected. Sediment meeting the NEL are considered clean.

The Lowest Effect Level: The Lowest Effect Level (LEL) indicates a level of contamination that can be tolerated by the majority of sediment-dwelling organisms. Sediments meeting the LEL) are considered clean to marginally polluted.

The Severe Effect Level: The Severe Effect Level (SEL) indicates a level of contamination that is expected to be detrimental to the majority of sediment-dwelling organisms. Sediments exceeding the (SEL) are considered heavily contaminated.

The protocol and rationale for setting PSQGs is provided in Appendix A. PSQGs are provided below in the following tables for metals and nutrients (Table 1), PCBs and organochlorine pesticides (Table 2a), and Polycyclic Aromatic Hydrocarbons (Table 2b). Background concentrations for metals and organic compounds are provided on Table 3 and 4, respectively.

Application of Sediment Quality Guidelines (2.2)

The Provincial Sediment Quality Guidelines (PSQGs) shown in Tables 1 and 2 provide the basis for all sediment (or potential lakefill materials to be placed in water) evaluations in Ontario. The guidelines pertain mainly to activities within the aquatic environment and adherence to them is not to be construed as exemption from the requirements of other guidelines, policies, or regulations of this Ministry or other agencies (e.g., the placement of contaminated sediment at an upland site or facility will be subject to the requirements of the Ministry’s Waste Management Regulations). The PSQGs can be used in making decisions on a number of sediment-related issues ranging from prevention of sediment contamination to remedial action for contaminated sediment. Issues to be addressed include, but are not limited to, the following:

• As one line of evidence for assessing contaminated sediments as described in the sediment decision making framework (see Section II).
• Determining appropriate action with regard to sediment clean-up in areas with historic sediment contamination, as well as other areas of potential impact to the environment.
• Determining fill quality for lakefilling associated with shoreline development programs.
• Establishing the chemical suitability of substrate material for the restoration of benthic habitat.
• Determining the appropriate degree of sediment clean-up as a result of chemical spills or unauthorized discharge.

The Evaluation Process (2.3)

Initial evaluation of bottom sediment or fill material is conducted by comparing the chemical concentrations of the material to the appropriate parameter values listed in Tables 1, 2a and 2b, and where required Tables 3 and 4, based on the conditions described in Section 2.3.1.

General Conditions Governing Evaluation (2.3.1)

1. Material will be tested by bulk sediment analyses and results reported on a dry weight basis, ideally as per MOE analytical methods (MOE 2004 a,b,c; 2005 a,b,c), or MOE approved equivalent analytical procedures.
2. When comparing analytical results with the PSQGs, the results will be rounded as follows: if the reported value is less than ten, it will be rounded to one significant digit. Values greater than 10 will be rounded to two significant digits.

   PSQG rounded value

   e.g.	Reported Value	Rounded Value
   <10	1.78	2
   <10	0.0364	0.04
   <10	0.0052	0.005
   >10	10.827	11
   >10	128.4	130

3. If all parameter values for a given material are at (or below) the NEL (if available), that material passes the guideline and it is anticipated that the material will have no adverse chemical effects on aquatic life or water quality.
4. If a single parameter value for a given material, based on a sampling program, exceeds the NEL but is below the LEL, the material fails the NEL and would be considered as having a negligible potential to impair the aquatic environment.
5. If a single parameter value for a given material, based on a sampling program, is at or above the LEL, that material fails the guideline and it is anticipated that such material may have an adverse effect on some benthic biological resources. If all values are below the LEL, no significant effects on benthic biological resources are anticipated.
6. If any single parameter value for a given material, as determined by a sampling program, is at or above the SEL, that material is considered highly contaminated and will likely have a significant effect on benthic biological resources.
7. The Ministry recognizes that in an area as geologically diverse as Ontario, local natural sediment levels of metals may vary considerably and in certain areas, such as wetlands, the organic matter content and nutrient levels may be naturally high.

Metals: In areas where local background levels are above the LEL, the local background level will form the practical lower limit for management decisions. In some waterbodies, surficial sediments upstream of all discharges may be acceptable for calculation of background values. Where it cannot be shown that such areas are unaffected by local discharges, the pre-colonial sediment horizon can be used. Site specific background for metals is calculated as the mean of 5 replicate samples from surficial sediment that has not been directly affected by human activity or from the ‘pre-colonial’ sediment horizon. The calculations are described in Appendix A of this document. Alternatively, the mean background values for the Great Lakes Basin as presented in Table 3 may be used.

Nutrients: Areas of high natural organic matter content, such as marshes and other types of wetlands, can be readily distinguished from those resulting from anthropogenic sources. In such cases, for the nutrients listed in Table 1, the local background would serve as the practical lower limit for management action.

It is also recognized that long-range sources such as atmospheric deposition have contributed to accumulation of organic compounds in areas remote from any specific source. Therefore, in those areas where specific sources cannot be determined, the practical lower limit for management action is the Upper Great Lakes deep basin surficial sediment concentration. These have been defined for a number of organic compounds and are presented in Table 4.

Specific Applications (2.3.2)

If the sediment concentration exceeds the Lowest Effect Level, then the concentration is compared with the local background values for that parameter. Background values can be derived from physically contiguous areas that are unaffected by point-source discharges, or if these do not exist, then from the "pre-colonial" sediment horizon. The latter would represent background levels in existence before European colonization of the area and is generally considered as the area below the Ambrosia pollen horizon. In those instances where local values are not available, the concentration may be compared to the background values listed in Tables 4. These are based on values from the Great Lakes and may not be applicable to inland sites.

If the sediment concentration is below the natural background then no further management decisions need to be considered. In areas where contaminants in sediment are at or above the Severe Effect Level, the sediment is deemed to be highly contaminated. When there are exceedances of the LEL or SEL, further testing and the development of a management plan may be required.

Figure D-1: Categorization of Fill for Lakefilling

(Reprinted from Fill Quality Guide and Good Management Practices for Shore Infilling in Ontario, 2011)

Figure D-2: Site Specific Sediment Criteria for Organic Compounds

Figure D-3: Site Specific Sediment Criteria for Other Parameters