STUDENT PROJECT ETHICAL REVIEW (SPER

STUDENT PROJECT ETHICAL REVIEW (SPER) FORM

The aim of the University’s Research Ethics Policy is to establish and promote good ethical practice in the conduct of academic research. The questionnaire is intended to enable researchers to undertake an initial self-assessment of ethical issues in their research. Ethical conduct is not primarily a matter of following fixed rules; it depends on researchers developing a considered, flexible and thoughtful practice.

The questionnaire aims to engage researchers discursively with the ethical dimensions of their work and potential ethical issues, and the main focus of any subsequent review is not to ‘approve’ or ‘disapprove’ of a project but to make sure that this process has taken place. The Research Ethics Policy is available at www.rgu.ac.uk/research-ethics-policy Student Name

Brendan McVeigh

Supervisor

Dr Prince Boateng Ecological and Economic viability of Beneficially

Project Title

Reusing

Dredged

Materials

for

Reclamation

Projects

Course of Study

MSc Construction Project Management

School/Department

The Scott Sutherland School

PART 1: DESCRIPTIVE QUESTIONS Does the research involve, or does information in the research 1.

relate to:

Ye s

No

[see Guidance Note 1]

(a) individual human subjects

X

(b) groups (e.g. families, communities, crowds)

X

(c) organisations

X


Brendan McVeigh (1312187)

(d) animals?

X

(e) genetically-modified

organisms

X

www.rgu.ac.uk/hr/healthsafety/page.cfm?pge=26027#122628

Please provide further details: Information obtained via the questionnaire originates from organisations that are directly or indirectly involved in the dredging sector.

Will the research deal with information which is private or 2.

Ye

confidential?

s


X

No

Please provide further details: Information collected for the literature review was collected from sources that were made public. However, some of the information collected during the questionnaire could be deemed to be sensitive. As a result, company names, locations and project names were omitted from the paper.

PART 2: THE IMPACT OF THE RESEARCH In the process of doing the research, is there any potential for 3.

harm to be done to, or costs to be imposed on: 3(i)]

[see Guidance Note

Ye s

No

(a) research participants?

X

(b) research subjects?

X

[see Guidance Note 3(ii)]

(c) you, as the researcher?

X

(d) third parties?

X

[see Guidance Note 3(iii)]

Page i



Please state what you believe are the implications of the research: N/A

4.

When the research is complete, could negative consequences follow:

Ye

No

s

(a) for research subjects

X

(b) or elsewhere?

X


Please state what you believe are the consequences of the research: N/A

PART 3: ETHICAL PROCEDURES 5.

Does the research require informed consent or approval from:

Ye

No

s

[see Guidance Note 5(i)]

(a) research participants?

X

(b) research subjects?

X

(c) external bodies?

[see Guidance Note 5(ii)]

X

[see Guidance Note 5(iii)]

If you answered yes to any of the above, please explain your answer: N/A

Page ii



Ye 6.

Are there reasons why research subjects may need safeguards or protection?

s

No


X If you answered yes to the above, please state the reasons and indicate the measures to be taken to address them: N/A

7.

Does the research involve any “regulated work with children”

Ye

and/or “regulated work with protected adults”, therefore

s

No

requiring membership of the Protecting Vulnerable Groups (PVG) Scheme?


X

[Please note: if the research potentially involves “regulated work”, this MUST be raised with your HR Business Partner immediately. In this instance, the Human Resources Department will conduct a detailed assessment and will confirm whether or not PVG Membership is required.] (a) PVG membership is not required.

X

(b) PVG membership may be required for working with children.

X

(c) PVG membership may be required for working with protected adults. (d) PVG membership may be required for working with both children and protected adults.

X

X

Page iii



If you answered yes to (b), (c) or (d) above, please give further information about the work you will be required to undertake and the nature of the contact with these groups. Please provide as much detail as possible: N/A

Ye s

Are you already a PVG member?

No X

If yes, please provide your PVG Scheme number: Ye 8.

Are specified procedures or safeguards required for recording, management, or storage of data?

s

No


X If you answered yes to any of the above, please give details: N/A

Page iv



PART 4: THE RESEARCH RELATIONSHIP Does the research require you to give or make undertakings to 9.

research participants or subjects about the use of data?

[see

Ye s

Guidance Note 9]

No X

If you answered yes to the above, please outline the likely undertakings: N/A

Ye 10

Is the research likely to be affected by the relationship with a

.

sponsor, funder or employer?

s

No


X If you answered yes to the above, please identify how the research may be affected: N/A

Part 5: Other Issues Ye 11

Are there any other ethical issues not covered by this form

.

which you believe you should raise?

s

No X

N/A

Page v



Statement by Student I believe that the information I have given in this form is correct, and that I have addressed the ethical issues as fully as possible at this stage. Signature:

Date :

16/09/2018

If any ethical issues arise during the course of the research, students should complete a further Student Project Ethical Review (SPER) form.

The Research Ethics Policy is available at www.rgu.ac.uk/research-ethics-policy

PART 6: TO BE COMPLETED BY THE SUPERVISOR

12 .

Does the research have potentially negative implications for the University? [see Guidance Note 11]

Ye s

No √

If you answered yes to the above, please explain your answer:

Page vi



Ye 13

Are any potential conflicts of interest likely to arise in the

.

course of the research?

No

s


√ If you answered yes to the above, please identify the potential conflicts:

Ye 14

Are you satisfied that the student has engaged adequately with

.

the ethical implications of the work?

No

s


√ If you answered no to the above, please identify the potential issues:

15 .

Appraisal: Please select one of the following i. The research project should proceed in its present form – no further action is required

√

ii. The research project requires ethical approval by the School Ethics Review Panel (SERP) (or equivalent) iii. The research project requires ethical review by the University’s Research Ethics Sub-Committee iv. The project needs to be returned to the student for modification prior to further action

Page vii



v. The research project requires ethical review by an external body (N.B. Question 5 above). If this applies, please give these details: Title of External Body providing ethical review Address of External Body Anticipated

date

when

External

Body may consider project

AFFIRMATION BY SUPERVISOR I have read the student’s responses and have discussed ethical issues arising with the student. I can confirm that, to the best of my understanding, the information presented by the student is correct and appropriate to allow an informed judgement on whether further ethical approval is required. Signature:

Prince Boateng

Date :

20/08/2018

Page viii



2018

WORD COUNT 16,750

BRENDAN MCVEIGH (1312187)

MSC CONSTRUCTION PROJECT MANAGEMENT | Robert Gordon University

Page ix



Caption Page

The Robert Gordon University, Aberdeen The Scott Sutherland School MSc Construction Project Management Ecological and Economic Viability of Beneficially Using Dredged Materials for Reclamation Projects Brendan McVeigh September, 2018

Page x



Title Page

Ecological and Economic Viability of Beneficially Using Dredged Materials for Reclamation Projects Brendan McVeigh September, 2018

This Dissertation is submitted in partial fulfilment of the requirements for the degree of Master of Construction Project Management at The Robert Gordon University, Aberdeen.”

Page xi



Declaration Page

“The content of this dissertation is the result of my own investigation, except where stated otherwise. It has not been accepted for any degree, nor been concurrently submitted for any other degree within or outside Robert Gordon University. I take full responsibility of the authenticity, sources and originality of the content used in this dissertation.”

Brendan McVeigh University ID: 1312187 September, 2018

Page xii



Abstract

For many years, dredged sediments have been treated as a waste material and disposed of at sea. With little effort made to promote dredged material as a valuable natural resource with the potential to relieve the strain on traditional primary resources. This dissertation is in relation to the ecological and economic benefits associated with reusing dredged material in reclamation projects. The literature review examined the importance of dredging in relation to economic and social development, the issue with sea disposal of dredged materials and the significances of sediment characterisation. The literature review then studies the equipment used for dredging and reclamation activities, plus the options available in relation to the beneficial use of dredged materials. This research utilised a combination of quantitative and qualitative research, to adopt a mixed method approach. The literature review comprehensively explores secondary data, while a questionnaire explores the primary data collected from professionals involved in the dredging sector across the globe. While there is a general awareness that dredged material can be beneficially used in Engineering projects, for Environmental Enhancement and Agricultural & Product Uses, there remains a distinct lack of emphasis on its use. The findings of the dissertation recommend that the dredging sector follows the example of the US and Japan, where up to 80% and 90% of dredged materials have been put to beneficial use. Legislation must be adopted to promote dredged material as a natural resource and to encourage its beneficial use, while greater material management is required for material characterisation and selection of dredging equipment. The recommendations provide a flowchart to show which sediment types are suited to certain beneficial use schemes and the appropriate equipment to use. The conclusion also finds that there are many factors that contribute to whether a project can be economic and environmentally successful, Page xiii



each project must be assessed on an individual basis due to the uniqueness of each dredging site and its ecosystem.

Keywords: Dredged Material, Sediment, Beneficial Use, Natural Resource, Stabilisation, Solidification, Reclamation, Sea Disposal and Dredging Equipment.

Page xiv



Acknowledgements

I am grateful to my Supervisor, Dr Prince Boateng (PhD, MSc, AFHEA, MASCE,M.eCOST, SDS) in the Scott Sutherland School for his guidance and help throughout the duration of the dissertation. I would like to express my appreciation to Eric. A. Stern (Partner/Director of Sediment Management and Development at Tipping Point Resource Group LLC) and Greg Kroef (Managing Director at Heron Construction Co Ltd) for their guidance, support and providing sources of information for the dissertation. My deepest gratitude goes to my wife Alice McVeigh and son Leo McVeigh for their continued support during my studies. I would also like to thank everyone whom participated in the questionnaire, without this information the dissertation would not have been possible. Brendan McVeigh September, 2018.

Page xv



CONTENTS Caption Page ............................................................................................. x Title Page ................................................................................................. xi Declaration Page ...................................................................................... xii Abstract ..................................................................................................xiii Acknowledgements .................................................................................. xv List of Figures ......................................................................................... xxi List of Tables ........................................................................................ xxvii List of Abbreviations .............................................................................. xxxii 1.0

Introduction ...................................................................................... 2

1.1

Background .................................................................................... 2

1.2 Problem Statement ............................................................................ 5 1.3 Research Aim and Objectives .............................................................. 7 1.4 Research Questions ........................................................................... 8 1.5 Proposed Methodology ....................................................................... 9 1.6 Significance of the Dissertation ............................................................ 9 1.7 Proposed Outline ............................................................................. 10 1.8 Research Timeline............................................................................ 12 1.9 Conclusion ...................................................................................... 13 2.0 Literature Review ............................................................................... 15 2.1 Dredging, Sediment & Dredged Materials Definitions ............................ 15 2.1.1 Dredging Definition .................................................................... 15 2.1.2 Sediment Definition .................................................................... 15 2.1.3 Definition of Dredged Material...................................................... 15 2.2 Capital & Maintenance Dredging ........................................................ 16 2.2.1 Maintenance Dredging ................................................................ 16 Page xvi



2.2.2 Capital Dredging ........................................................................ 17 2.3 The Importance of Dredging.............................................................. 18 2.4 Legislation Regulating the Sea Disposal of Dredged Material ................. 18 2.5 Dredged Materials & Sea Disposal ...................................................... 20 2.6 Environmental Issues Relating to The Sea Disposal of Dredged Materials 27 2.7 Dredged Material as A Resource ........................................................ 31 2.8 Dredged Material Management .......................................................... 33 2.9 Site Investigation – Sediment Sampling, Testing & Evaluation ............... 35 2.9.1 The Importance of Site Investigation ............................................ 35 2.9.2 Bathymetric Survey .................................................................... 40 2.9.3 Geological & Geotechnical Investigations ....................................... 40 2.9.4 Environmental Impact Assessment .................................................. 55 2.10 Overview of Equipment & Techniques Used During Dredging & Material Stabilisation Projects ............................................................................. 57 2.10.1 Types of Dredging Equipment .................................................... 57 2.10.2 Hydraulic Dredgers ................................................................... 58 2.10.3 Mechanical Dredgers ................................................................. 65 2.10.4 Hydrodymanic Dredgers ............................................................ 72 2.10.5 Dredged Material Processing and Stabilisation .............................. 73 2.11

Beneficial Use of Dredged Materials .............................................. 85

2.11.1 Beneficial Usage Options ........................................................... 87 2.11.1.2 Beneficial Use Hierarchy .......................................................... 104 2.12.0 Stabilisation of Dredged Material for Reclamation .......................... 106 2.13.0 Economic Benefits of Beneficially Using Dredged Materials.............. 112 2.14.0 Environmental Benefits of Beneficially Using Dredged Materials....... 118 2.15 Conclusion .................................................................................. 119 3.0

Research Methodology.................................................................... 121 Page xvii



3.1 Introduction .................................................................................. 121 3.2 Research Methodology.................................................................... 121 3.2.1 Quantitative Research ............................................................... 122 3.2.2 Qualitative Research ................................................................. 122 3.2.3 Mixed Research Method (MRM) .................................................. 124 3.2.4 Literature Review ..................................................................... 125 3.2.5 Questionnaire Design ................................................................ 126 3.2.6 Data Sources ........................................................................... 126 3.3 Data Collection Sampling ................................................................ 127 3.4 Data Collection Limitations .............................................................. 128 3.5 Data Analysis ................................................................................ 128 3.6 Conclusion .................................................................................... 128 4.0

Data Collection & Analysis............................................................... 130

4.1 Introduction .................................................................................. 130 4.2 Presentation.................................................................................. 131 4.3 Analysis & Amalgamation of Data .................................................... 131 4.4 Respondent Details & Rate of Response ............................................ 131 4.3 Question 1, Analysis & Findings ....................................................... 135 4.3.1 Analysis of Question 1 .............................................................. 136 4.4 Question 2, Analysis & Findings ....................................................... 137 4.4.1 Analysis of Question 2 .............................................................. 138 4.5 Question 3, Analysis & Findings ....................................................... 140 4.5.1 Analysis of Question 3 .............................................................. 140 4.6 Question 4, Analysis & Findings ....................................................... 141 4.6.1 Analysis of Question 4 .............................................................. 141 4.7 Question 5, Analysis & Findings ....................................................... 143 4.7.1 Analysis of Question 5 .............................................................. 143 Page xviii



4.8 Question 6, Analysis & Findings ....................................................... 145 4.8.1 Analysis of Question 6 .............................................................. 145 4.9 Question 7, Analysis & Findings ....................................................... 146 4.9.1 Analysis of Question 7 .............................................................. 146 4.10 Question 8, Analysis & Findings ..................................................... 147 4.10.1 Analysis of Question 8 ............................................................. 148 4.11 Question 9, Analysis & Findings ..................................................... 149 4.11.1 Analysis of Question 9 ............................................................. 149 4.12 Question 10, Analysis & Findings.................................................... 150 4.12.1 Analysis of Question 10 ........................................................... 150 4.13 Question 11, Analysis & Findings.................................................... 151 4.13.1 Analysis of Question 11 ........................................................... 151 4.14 Question 12, Analysis & Findings.................................................... 153 4.14.1 Analysis of Question 12 ........................................................... 153 4.15 Question 13, Analysis & Findings.................................................... 155 4.15.1 Analysis of Question 13 ........................................................... 155 4.16 Question 14, Analysis & Findings.................................................... 157 4.16.1 Analysis of Question 14 ........................................................... 157 4.17 Question 15, Analysis & Findings.................................................... 158 4.17.1 Analysis of Question 15 ........................................................... 158 4.18 Question 16, Analysis & Findings.................................................... 159 4.18.1 Analysis of Question 16 ........................................................... 159 4.19 Question 17, Analysis & Findings.................................................... 160 4.19.1 Analysis of Question 17 ........................................................... 160 4.20 Question 18, Analysis & Findings.................................................... 161 4.20.1 Analysis of Question 18 ........................................................... 162 4.21 Question 19, Analysis & Findings.................................................... 163 Page xix



4.21.1 Analysis of Question 19 ........................................................... 164 4.22 Question 20, Analysis & Findings.................................................... 165 4.22.1 Analysis of Question 20 ........................................................... 166 4.23 Question 21, Analysis & Findings.................................................... 167 4.23.1 Analysis of Question 21 ........................................................... 168 4.24 Question 22, Analysis & Findings.................................................... 169 4.24.1 Analysis of Question 22 ........................................................... 170 4.25 Question 23, Analysis & Findings.................................................... 171 4.25.1 Analysis of Question 23 ........................................................... 172 4.26 Question 24, Analysis & Findings.................................................... 173 4.26.1 Analysis of Question 24 ........................................................... 173 4.27 Question 25, Analysis & Findings.................................................... 175 4.27.1 Analysis of Question 25 ........................................................... 175 4.28 Chapter 4 Conclusion ................................................................... 176 5.0 Conclusion ....................................................................................... 178 5.1 Recommendations .................................... Error! Bookmark not defined. References ............................................................................................ 188

Page xx



List of Figures Figure 1: Topics discussed in the introduction chapter. Figure 2: Volumes of DM disposed at sea from 1990 and 2005, volumes range between 80 million to 130 million tonnes. Figure 3: Dissertation structure. Figure 4: Heron Construction’s Mesenge flattop barge carrying out MD in the Rangitoto Channel to provide safe water depths for vessels using the Port of Auckland in New Zealand. Figure 5: Royal Boskalis’ Manu-Pekka and Magnor backhoe dredgers carrying out CD for Graham Lagan Joint Venture on Siemen’s redevelopment of Green Port Hull in England. Figure 6: The main environmental effects of sea disposal of DM (OSPAR JAMP, 2009). Figure 7: Volume of CD & MD material disposed of at sea by Ireland & the volume of DM put to BU between 1997 & 2006 (Sheenan et al, 2009). Figure 8: The amount of DM disposed at sea in the Marine Environment of the North-East Atlantic Ocean from 1990 to 2005, volumes range between 80 million to 130 million tonnes and correlate to dredging activities (OSPAR Commission, 2010). Figure 9: Represents the amount of sediment in dry tonnes, disposed of by Belgium in the Belgium area of the North Sea (Van den Eynde et al, 2013). Figure 10: Shows the total amount (in million tonnes) of DM disposed within the OSPAR Martine Area per country, between the period of 2008 and 2014 (OSPAR Work Area, 2017). Figure 11: Highlights the volume of DM disposed of at sea across Australia in 2006, 2011 & 2016 (State of the Environment, 2016).

Page xxi



Figure 12: Dredging phases & the potential environmental impacts of dredging, sediment transportation & sea disposal (Manap & Voulvoulis, 2014). Figure 13: Potential environmental impacts of dredging (Elliott & Hemingway, 2002). Figure 14: Details the potential environmental impacts of dredging (Elliott & Hemingway, 2002). Figure 15: Questions answered by a detailed site investigation (IADC-SI, 2015) & (Maher et al, 2013). Figure 16: Areas in which a site and geotechnical investigation may assist a project team, adopted from Geotechnical Investigations for Dredging Projects (Johnson, 2005). Figure 17: Shows the potential consequences of an inadequate site investigation (Johnson, 2005). Figure 18: Shows how adequate site investigation lead to successful dredging and reclamation projects (Johnson, 2005). Figure 19: Three main aspects of ground examination required to collect adequate data during a site investigation (IADC-SI, 2015). Figure 20: Information produced as a result of Bathymetric Surveying (IADC-SI, 2015). Figure 21: Factors that determine the sampling and testing methods when considering DM for BU projects (Maher et al, 2013). Figure 22: Steps for developing a pre-dredge survey (Harrington & Smith, 2013) & (PREMIAM, 2011). Figure 23: The three most common methods used to extract core samples from a proposed dredge area (Maher et al, 2013). Figure 24: Diagram shows an electronic Vibra-Corer used to collect sediment samples for dredging projects (USGC, 2018).

Page xxii



Figure 25: Shows a Gravity Corer used to collect sediment samples for dredging projects (Virtuel, 2018). Figure 26: Shows a Piston Corer used to collect sediment samples for dredging projects (Boes, 2015). Figure 27: Typical grab used to collect sediment samples for dredging projects (IndiaMart, 2018). Figure 28: Shows information that can be made available to the project team by conducting an EIA (IADC-SI, 2015). Figure 29: Plain Suction Dredger used for the hydraulic extraction of cohesionless sediment (DredgeYard, 2018). Figure 30: Shows a booster pump connected to a floating pipeline, to assist with the transportation of dredged material (RoyalIHC, 2018). Figure 31: Graphical illustration of a Jan De Nul Cutter Suction Dredger connected to a floating pipeline (JDN-IADC, 2014). Figure 32: Graphical illustration of the draft of a Jan De Nul Cutter Suction Dredger equipped with rotating cutter head to dislodge cohesive sediments & suction hose located within the ladder for the extraction of DM (JDN-IADC, 2014). Figure 33: Two CHs, the CH on the left is used to extracting clays (Morijn, 2011), while the CH on the right is used for the removal of rock (Everflowing, 2018). Figure 34: Depicts a TSHD with suction tube deployed on the seabed (JDN, 2018). Figure 35: Shows a TSHD’s draghead attached to the end of a suction tube to remove material from the seabed (JDN, 2018). Figure 36: TSHD using its bottom opening doors to release DM over a disposal site (JDN, 2018). Figure 37: Shows a TSHD placing DM by rain bowing (RoyalIHC-TSHD, 2018). Figure 38: BUD suction pump with high-pressure jets (Damen, 2018).

Page xxiii



Figure 39: BUD sucking DM from a hopper barge & pumping ashore (Damen, 2018). Figure 40: Graphical representation of a BLD (MadeInChina, 2018). Figure 41: DEME Group’s Adriatico BLD (BalticShipping, 2018). Figure 42: Clamshell attachment used by Heron Construction Co. Ltd. on the Messenge barge for dredging of soft clays, silts and sands. Figure 43: Heron Construction’s Messenge barge with Hitachi EX700 mechanical excavator using clamshell attachment to load hopper barge while performing maintenance dredging at Auckland’s Rangitoto Channel. Figure 44: East Marine’s Bestla Grab Dredger with 10m³ clamshell attached to line (EastMarine, 2014). Figure 45: Heron Construction’s Kimahia backhoe dredgers carrying out capital dredging works for the Port of Napier in New Zealand. Figure 46: Royal Boskalis’ Magnor backhoe dredgers carrying out capital dredging works for berthing pockets at Graham Lagan Joint Venture on Siemen’s redevelopment of Green Port Hull in England. Figure 47: Shows a Van Oord WIJ Dredger & a graphic of a horizontal jetting bar positioned over a dredge area (Van Oord, 2014). Figure 48: Shows a tug boat dragging a blade across a dredge area (DAMEN, 2017). Figure 49: Shows the dewatering process of DM from a hopper barge (Maher et al, 2013). Figure 50: Shows the working principle of a large diameter dewatering plant (Oida, 2007). Figure 51: Hiway GeoTechnical’s excavator with rotary head & high-pressure grout injection hose, preforming MSS at the Southern Pipeline Project in Tauranga New Zealand.

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Figure 52: Excavator with rotary head & high-pressure grout injection hose, used for MSS of DM in a CDF (Wilk, 2015). Figure 53: Excavator with rotary head & high-pressure grout injection hose, PSS of DM in a hopper barge (Wilk, 2015). Figure 54: Heron Construction’s Mesenge Barge processing DM from a hopper barge into mudcrete to create a bund wall at the Port of Auckland in New Zealand. Figure 55: Mesenge pugmill barge’s EX700 longreach excavator placing mudcrete at the Port of Auckland reclamation. Figure 56: Illustrates dredged sediments passing through the PFTM and subsequently mixed with a binding agent via turbulence (Stern et al, 2018). Figure 57: Illustrates the PSS of DM using a PFTM (Stern et al, 2018). Figure 58: Range of available treatment options for CDM, these treatments can be preselected in accordance with the characteristics of the DM. The figure has a key listing which type of DM can be treated by each method and indicates which methods are most economically viable (Bortone et al, 2004). Figure 59: BU Hierarchy, showing the preferred order of use (Sheehan, 2012). Figure 60: Procedure used for PSS of CDM at the Port of Turku (STABLE, 2009). Figure 61: Procedure used for MSS of CDM at the Port of Turku (STABLE, 2009). Figure 62: Factors to review when considering in-situ stabilisation of DM (Druijf, 2016). Figure 63: Procedure used for In-situ stabilisation of DM at the Port of Valencia (Druijf, 2016). Figure 64: Land reclamation method at the Port of Valencia (Burgos, Samper, & Alonso, 2006) & (Druijf, 2016). Figure 65: Cost Benefit Analysis Formulation (Gatto, 2014). Figure 66: Desired information from the “Beneficial Reuse of Dredged Material” questionnaire.

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Figure 67: Shows the table on the cover page of the “Beneficial Reuse of Dredged Material” questionnaire for the collecting of the respondent’s information. Figure 68: Represents the overall percentage of dredged sediments that originated from MD projects. Figure 69: Provides an indication of the percentage of dredged sediments that detected the presence of a contaminant. Figure

70:

Shows

the

percentage

of

respondents

that

considered

stabilisation/solidification after samples had underwent analysis. Figure 71: Shows the percentage of organisations that further investigated stabilisation/solidification agents for the DM. Figure 72: Shows the percentage of DM that was utilised for BU. Figure 73: Shows the percentage of DM that was utilised for BU that originated from MD projects. Figure 74: Depicts the types of BU schemes and the number of responding organisations participating in each scheme. Figure 75: Research objectives.

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List of Tables Table 1: Impacts associated with dredging activities (IADC, 2005). Table 2: Alternative use for DM that are not deemed to be waste (IADC, 2005). Table 3: Dissertation timeline. Table 4: Lists international agreements and conventions created to govern the sea disposal of waste & DM (Van den Eynde et al, 2013). Table 5: Lists European Directives created to govern the sea disposal of waste & DM (Van den Eynde et al, 2013). Table 6: Lists the numerous potential environmental impacts of dredging, sediment transportation and sea disposal activities (Manap & Voulvoulis, 2014). Table 7: Chart showing the information required from a site investigation (Van t’ Hoff et al, 2012). Table 8: Comparison of SI Techniques (Kinlan & Roukema, 2010). Table 9: Indicates the number of sample stations required in relation to the dredge volume (OSPAR Commission, 2014). Table 10: Physical characteristics of DM to be identified during physical testing, adopted from (Sheehan & Harrington, 2012) & (Harrington & Smith, 2013). Table 11: Information required from physical characterisation of dredged sediments (OSPAR Commission, 2014). Table 12: Physical characteristics of DM to be identified during chemical testing (Harrington & Smith, 2013) and (PIANC, 1992).

Table 13: Information required from chemical characterisation of DM (OSPAR Commission, 2014). Table 14: Information required from biological characterisation of DM (OSPAR Commission, 2014). Table 15: Action Levels & description (Deara, 2016). Page xxvii


Table 16:


Factors influencing the selection of stabilising agent for BU of DM

(Maher et al, 2013). Table 17: Summary of dredger capabilities (Vlasblom, 2003). Table 18: Options available when considering treatment of CDM (Bortone et al, 2004). Table 19: Lists the advantages & disadvantages associated with BU of DM for wetland enhancement & creation (Harrington & Smith, 2013). Table 20: Lists the advantages & disadvantages associated with BU of DM for upland enhancement & creation (USACE, 2015). Table 21: Lists the advantages & disadvantages associated with BU of DM for aquatic habitat enhancement & creation (USACE, 2015). Table 22: Lists the advantages & disadvantages associated with using DM for lining & capping of landfill facilities (Harrington & Smith, 2013). Table 23: Lists the advantages & disadvantages associated with using DM for road & subbase construction (Harrington & Smith, 2013). Table 24: Lists the advantages & disadvantages associated with using DM for concrete manufacture (Harrington & Smith, 2013). Table 25: Lists the advantages & disadvantages associated with using DM for manufacturing brick, block & tiles (Harrington & Smith, 2013). Table 26: Advantages & disadvantages associated with BU of DM for manufactured top soil (Harrington & Smith, 2013). Table 27: Advantages & disadvantages associated with using DM for beach nourishment (Harrington & Smith, 2013). Table 28: Advantages & disadvantages associated with BU of DM for offshore berm construction (Harrington & Smith, 2013). Table 29: Lists the advantages and disadvantages associated with using dredged materials for coastal protection works (Harrington & Smith, 2013).

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Table 30: Advantages & disadvantages associated with BU of DM for sediment cell maintenance (Harrington & Smith, 2013). Table 31: Highlights the advantages & disadvantages associated with using DM for land reclamation (Harrington & Smith, 2013). Table 32: Land reclamation options for varying types of DM (Harrington & Smith, 2013), (Sheehan, 2012) & (Chen & Tan, 2002). Table 33: Site specific material selection for engineering use (Murray, 2008). Table 34: Describes & classifies some of effects that may result from a new dredging project (Gatto, 2014). Table 35: Describes some of positive & negative effects that may result from a new dredging project & the magnitude of those effects (Gatto, 2014). Table 36: Lists the factors that influence the economic success of a land reclamation project (Kolman, 2012). Table 37: The main differences between qualitative and quantitative research (Minichiello, 1990). Table 38: 13 Steps of the Mixed Research Method (Collins et al, 2006). Table 39: Sows the distribution of the questionnaire, plus the type of organisations that were asked to participate in the survey. Table 40: Presents the number of respondents to the questionnaire and, whether they work for a Port/Harbour, dredging contractor or a consultant. Table 41: Shows the response rate to the questionnaire from each organisation type. Table 42: Shows the number of questionnaire participants that recently partook in a dredging project. Table 43: Lists the type of dredging project & the number of organisations involved in each project type.

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Table 44: Details volumes extracted by organisations on recent dredging projects. Table 45: Details the types of materials dredged and the percentage dredged by each organisation. Table 46: Represents the percentage of DM disposed of at sea and the number of projects each percentage is disposed on. Table 47: Shows the percentage of organisations that considered DM to be a natural resource. Table 48: Shows whether organisations are carrying out SI to determine if DM has a potential for BU. Table 49: Shows organisations are detecting a range of contaminants during SI. Table 50: List of contaminants discovered during SI. Table 51: Indicates if organisations had been involved in land reclamation of port expansion projects. Table 52: Indicates if organisations had used S/S technologies for land reclamation projects. Table 53: Indicates whether an EIA had been conducted for the projects that the respondents had worked on. Table 54: Details if respondent organisations invested in new equipment for future BU projects. Table 55: Lists equipment used by the respondents to carryout S/S treatment of DM. Table 56: Details several environmental impacts found on BU projects by the survey respondents. Table 57: Lists a number of the financial influences found on BU projects by the survey respondents. Table 58: Details some of the economic advantages and disadvantages found on S/S projects for BU.

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Table 59: Details some of the logistical advantages and disadvantages found on S/S projects for BU. Table 60: Highlights advantages and disadvantages responding organisations had encountered when carrying out S/S of DM for BU. Table 61: Details whether or not organisations that participated in the survey use a process flowchart to assist with the selection of BU options for DM. Table 62: Shows whether or not the respondent’s organisations consulted the general public in relation to the BU of DM. Table 63: Beneficial Use of DM for Environmental Enhancement (Harrington & Smith, 2013). Table 64: Beneficial Use of DM for Agricultural & Product purposes (Harrington & Smith, 2013). Table 65: Beneficial Use of DM for Engineering purposes (Harrington & Smith, 2013).

Page xxxi



List of Abbreviations BES: Bentonite-Enriched Soil BHD: Backhoe Dredge BLD: Bucket Ladder Dredge BU: Beneficial Use BUD: Barge Unloading Dredge CBR: California Bearing Ratio CCL: Compacted Clay Liners CCP: Coal Combustion Products CD: Capital Dredging CDF: Confined Disposal Facilities CDM: Contaminated Dredged Material CEDA: Central Dredging Association CFB: Circulating Fluidised Bed Boiler CH: Cutter Head CPW: Coastal Protection Works CSD: Cutter Suction Dredge DA: Dredging Activities DDT: Dichlorodiphenyltrichloroethane DH: Draghead DM: Dredged Material EEMP: Environmental Monitoring and Management Plan EIA: Environmental Impact Assessment Page xxxii



FA: Fly Ash FBT: Fluidized Bed Treatment FEPA: Food and Environmental Protection Act GD: Grab Dredge GGBS: Granulated Blast Furnace Slag IADC: International Association of Dredging Companies LKD: Lime Kiln Dust LL: Liquid Limit MD: Maintenance Dredging MHWS: Mean High Water Springs MRM: mixed research method MSS: Mass Stabilisation-Solidification NGO: Non-Governmental Organisations NOAA: National Oceanic and Atmospheric Administration N/A: Not Applicable OPC: Ordinary Portland Cement PAH: Polycyclic Aromatic Hydrocarbons PCBs: Polychlorinated Biphenyls PDM: Processed Dredged Material PDoEP: Pennsylvanian Department of Environmental Protection PFTM: Pneumatic Flow Tuber Mixer PI: Plastic Index PSD: Plain Suction Dredger PSS: Process Stabilisation-Solidification Page xxxiii



PVD: Pre-fabricated Vertical Drains QC: Quality Control QM: Quarried Material RD: Reclamation Dredger SA: Stabilising Agent SCM: Sediment Cell Maintenance SDA: Spray Dryer Ash SedNet: European Sediment Research Network SI: Site Investigation S/S: Stabilisation/Solidification TBT: Tributyltin TIE: Toxicity Identification Evaluation TSHD: Trailer Suction Hopper Dredge UCS: Unconfined Compressive Strength USACE: United States Army Corps of Engineers USEPA: United States Environmental Protection Agency UPD: Underwater Plough Dredger WIJ: Water Injection Dredger

Page xxxiv

Chapter 1 INTRODUCTION



1.0 Introduction This chapter supplies a brief description of the topic in relation to;

Background Probelm Statement Research Aim & Objectives Research Questions Proposed Methodology Significance of the Dissertation Proposed Outline & Research Timeline

Figure 1: Topics discussed in the introduction chapter.

1.1 Background Dredging is a necessary process consisting of the excavation of sediments from the seabed, ports, rivers, lakes, berthing pockets and channels, plus the relocation of the dredged material (DM) to an alternative location (CEDA, 2009) & (OceanService, 2017). While dredging and reclamation is necessary, they are associated with negative environmental impacts (World Trout Trust, 2013). Civilisations utilised waterways for centuries transporting people, materials, commodities and equipment around the globe (IADC, 2005). As population grows, so will the demand for greater volumes of goods to be transported, resulting in the

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need for larger, efficient and cost-effective vessels, with the likelihood of dredging activities (DA) to increase in the future. Due to increased draught of modern vessels, the demand for capital dredging (CD) and maintenance dredging (MD) projects has grown, demanding the deepening of ports, harbours, estuaries, turning basins, berth pockets and navigation channels (IADC, 2005). Resulting in greater volumes of DM being disposed of at sea, with the potential of adverse effects on the environment, marine life and food chain. With the scale of projects increasing and dredging equipment becoming larger to handle greater DM volumes, the extent of the environmental changes will depend on selected dredging and disposal techniques (OSPAR, 2010). The impact of DA is social and environmental. Dredging of contaminated dredged materials (CDM) can result in contaminated sediments entering the water table, where they may have a detrimental impact upon aquatic life (IADC, 2005).

IMPACTS OF DREDGING AND MATERIAL DISPOSAL Water quality, e.g. increase of suspended solids concentration and potential release of contaminants during dredging or disposal; leaching of contaminants from disposal sites; Archaeological assets, e.g. shipwrecks; Recreation, e.g. sailing, swimming and beach use; Habitats and natural areas, e.g. habitat enhancement or creation, removal or destruction of benthos, smothering; Economic activities, e.g. commercial fishing; improved infrastructure. Local communities, e.g. the effects of noise; increased labour opportunities; Physical processes, e.g. waves, currents or drainage & hence erosion or deposition; Changes to bathymetry or topography;

Table 1: Impacts associated with dredging activities (IADC, 2005). The majority of DM is dealt with by sea disposal, with limited amounts disposed of on land or recycled for construction purposes (OSPAR, 2010). Page 3



Over 90% of DM from navigational dredging projects remains unpolluted and undisturbed, yet it is underutilised as a natural resource and sustainable construction material (IADC, 2005) & (CEDA, 2009). The management of DM requires long-term planning and consideration to increase percentages of DM being put to beneficial use (BU). Focus must be placed upon the selection of innovative BU schemes and technologies. New major projects should complete detailed studies to identify potential benefits and adverse effects of DA. Studies identify impacts and alternatives for DA such as; 

Sustainable relocation,



BU,



Open water disposal,



Confined space disposal,



Treatment and stabilisation (IADC, 2005).

Developments in dredging equipment led to innovations such as automated control, positioning systems and degassing systems that minimise the impact a dredger has on the environment (IADC, 2005). CDM results in additional logistical issues, hazards to the environment and may require alternative measures to ensure CDM do not become suspended in the water column. Pre-treatment of DM may be necessary to allow consideration of CDM for BU. Treatment may include stabilisation/solidification (S/S) of DM and the capping of the contaminated area with clay, this will ultimately increase costs (CEDA, 2009). Several BU options for DM have been developed by the dredging industry. The BU of DM can be applied in three categories; Engineering Uses, Environmental Enhancement and Agricultural/Product Uses (Harrington & Smith, 2013).

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BENEFICIAL USE OF DREDGE MATERIALS Coastal protection works (CPW), e.g. beach nourishment, onshore/offshore feeding, managed retreat; Agriculture, horticulture, forestry; Habitat development or enhancement, e.g. aquatic habitats, bird habitats, mudflats, wetlands; Amenity development or enhancement, e.g. landscaping; Raising low-lying land; Land reclamation, e.g. for industrial development, housing, infrastructure; Production of construction material, e.g. bricks, clay, aggregates; Construction works, e.g. foundation fill, dikes.

Table 2: Alternative use for DM that are not deemed to be waste (IADC, 2005).

Large volumes of DM are disposed of at sea, if considered as a natural resource, it could be BU, providing both economic and ecological benefits. BU can be achieved by advanced planning in relation to the management of DM and selecting the most relevant equipment.

1.2 Problem Statement Public perception of dredging related activities is often negative. Dredging is characterised by some as a man-made modification of nature, that lacks awareness or underestimates its effects on the ecosystem (IADC, 2005). DA are widely perceived to be disruptive to the environment, with dredging projects associated with undesirable environmental consequences (Pictures, 2016). DA will have an impact on marine species and habitats located in close proximity to the dredging and disposal sites, the resuspension of sediments is a major

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contributor, due to the marine environment being affected by fluctuations in local chemical levels. The extent of the impact will be different for each project, as environments have their own characteristics and unique level of sensitivity. The scale of impact will depend on the dredging and DM disposal techniques selected (OSPAR Commission, 2010). The majority of uncontaminated DM from harbour and estuary dredging projects are disposed of at sea. The sea disposal of DM contributes to the resuspension of sediments, therefore effecting marine environments (IADC, 2005). Limited amounts of the DM are reconstituted beneficially, incorporated in land reclamation projects, construction projects or disposed of on land. Clear correlations can be established between DA and waste disposal at sea, with the problem likely to be exacerbated by an increase in CD and MD projects (OSPAR Commission, 2010). As the efficiency of dredging equipment, dredging techniques and global positioning systems improve, there is an opportunity for dredging projects to select efficient techniques to dredge and dispose of DM. Hence, minimising the impact of the project on the ecosystem and reduce operational costs. There is an opportunity to BU dredgings in the construction process and on other projects, by processing DM into products that will add economic or ecological value, as opposed to sea disposal. The dredging sector must review;

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The negative perception associated with dredging activities Environmental impacts relating to sea disposal of DM Volume of uncontaminated DM being disposed of at sea DM is not commonly recognised as a natural resource Insignificant amounts of DM are deployed on BU schemes BU options are perceived to be costly Can the selection of equipment encourage BU?

Figure 2: Lists issues that the dredging sector must review in relation to sea disposal of DM.

Consideration is required for the management of DM. In order to achieve improved environmental results, the industry must complete sediment sampling to define characteristics and assess BU options (USACE, 2015).

1.3 Research Aim and Objectives The aim of this dissertation is to provide alternative BU solutions for the disposal of DM. The dissertation aims to produce procedures to assist the project team with management decisions in relation to the BU of DM, allowing the selection of options that are economic and environmentally attractive. The paper pays particular interest to the S/S of DM for use in land reclamation projects, plus the factors that determine when the BU of stabilised sediment become economic and environmentally viable. The main objectives are; 

To examine the volume of DM disposed of at sea, Page 7





To discover the environmental impacts and costs associated with sea disposal,



To analyse the characteristics associated with DM and their potential for BU,



Critically appraise current management practices of DM and provide guidance for BU options.

1.4 Research Questions

1) How can the BU of DM be encouraged? 2) Is DM considered a natural resource? 3) Are site investigations (SI) conducted to determine the physical and chemical characteristics of sediments to identify BU options? 4) Does testing cover the placement site for the BU of DM to confirm compatibility? 5) Are CDM being considered for BU? 6) What are the main BU options? 7) Is specialist equipment required to BU of DM? 8) What are the logistical advantages and disadvantages associated with the S/S of DM for BU? 9) What are the main economic and environmental advantages/disadvantages associated with BU of DM? 10) What are the main economic and environmental advantages/disadvantages associated with S/S DM for BU in reclamation projects? 11) What are the recommendations for future researchers?

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1.5 Proposed Methodology

The methodology chosen for this dissertation was a mixed research method, combining quantitative and qualitative research methods. The approach involved reviewing published information in the form of a literature review, followed by a questionnaire that was sent to professionals working in the dredging sector, via email or an open invitation to participate in the survey, which was posted on dredging groups on the LinkedIn network. The questionnaire contained questions that were qualitative and quantitative in nature and varied from open-ended to close-ended. The quantitative questions allow the author to establish the amount of DM being disposed of at sea or BU. While the qualitative questions will allow the respondents to provide a detailed explanation of issues.

1.6 Significance of the Dissertation

Significance of the dissertation; 

Promote good practice in the management of DM use and minimise amounts of DM disposed of at sea.



Highlight the ecological and economic benefits of using DM.



Outline options for alternative disposal methods for DM.



Provide guidance for BU of DM.



Promote DM as a natural resource.

Page 9



1.7 Proposed Outline

The dissertation is divided into 5 chapters; Chapter 1 (Introduction) – Introduces the dissertation topic and the issues surrounding the subject. It provides an overview of the aims, objectives, research questions, significance and methodology used to achieve the research goals. Chapter 2 (Literature Review) – Provides a review of relevant literature relating to the topic. The chapter identifies the problems associated with sea disposal of DM, explores BU options and other factors that influence management and decision-making processes in relation to DM. Chapter 3 (Research Methodology) – Discusses the research methodology implemented for the dissertation and its selection. Chapter 4 (Data Collection & Analysis) – Analyses the responses to the questionnaire, identifying trends or significant findings. Chapter 5 (Conclusion & Recommendations) – Summarises the literature review in comparison with the findings from the survey questionnaire. This chapter also presents recommendations that may encourage BU of DM in an economic and environmental manner.

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Figure 3: Dissertation structure.

Page 11



1.8 Research Timeline

A timeline of the dissertation can be seen in Table 3; DISSERTATION TIMELINE Task

Task

Start Date

Finish Date

1.

Review problems associated with DM.

05/01/2018

02/02/2018

2.

Literature Review.

05/01/2018

30/04/2018

3.

Dredging definitions.

01/04/2018

06/04/2018

4.

Investigate BU options.

06/04/2018

13/04/2018

5.

Investigate dredging & stabilisation

13/04/2018

20/04/2018

No.

equipment. 6.

Investigate DM characteristics.

20/04/2018

27/04/2018

7.

Review the issue of sea disposal.

27/04/2018

04/05/2018

8.

Identify environmental impacts.

04/05/2018

11/05/2018

9.

Review possible solutions to sea disposal of

11/05/2018

18/05/2018

DM. 10.

Create questionnaire and send.

07/04/2018

30/04/2018

11.

Write the introduction chapter.

18/05/2018

25/05/2018

12.

Write the literature review chapter.

25/05/2018

08/06/2018

13.

Write the research methodology chapter.

08/06/2018

15/06/2018

14.

Collate information for questionnaires,

15/06/2018

22/06/2018

22/06/2018

29/06/2018

write the data collection & analysis chapter. 15.

Write the conclusion & recommendation chapter.

16.

Review & submit first draft.

06/07/2018

06/07/2018

17.

Review feedback & adjust

06/08/2018

16/09/2018

18.

Submit final draft.

16/09/2018

16/09/2018

Table 3: Dissertation timeline.

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1.9 Conclusion

Factors that affect the management of DM for reuse are sediment characteristics, site location, logistics, disposal and treatment costs. The majority of sediments dredged during CD and MD projects are disposed of at sea. A focus is required on the management of DM, projects must be implemented with greater foresight and an element of innovation, providing economically sustainable options. Dredging projects are unique and complex. Site conditions and material composition limit the available options when considering the BU of DM, e.g. certain projects may not have the option to stabilise DM for reclamation, due to economic factors, sediment characteristics or there is no requirement for reclamation. There is an opportunity to get greater BU of DM, several groups have spotted this missed opportunity and are currently investigating BU options. They are; 

ABPmer,



CEDA,



MMO,



RSPB,



Solent Forum (Ausden et al., 2018).

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Chapter 2 LITERATURE REVIEW

Page 14



2.0 Literature Review This chapter provides an understanding of DA, issues relating to sea disposal and an overview of dredging equipment. The literature review intends to explore DM characteristics and management options, while reviewing current BU options and the equipment used to stabilise/solidify DM for BU.

2.1

Dredging,

Sediment

&

Dredged

Materials

Definitions

2.1.1 Dredging Definition Dredging is a necessary process consisting of the excavation of materials from the seabed, lakes, rivers, ports and channels and its relocation to an alternative site (CEDA, 2009).

2.1.2 Sediment Definition Sediment is naturally produced, resulting from erosion by wind or water. Sediment is soil that has broken-down into basic components of sand, silt, clay and organic matter, it is carried into a waterbody where the particles settle on the bottom. Sediment may comprise of several particle types from fine silts and clays to coarse aggregates, these particles combine to produce an infinite variety of combinations (Maher et al, 2013).

2.1.3 Definition of Dredged Material DM is sediments that have been removed from a waterbody by dredging equipment (DredgDikes, 2018).

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2.2 Capital & Maintenance Dredging

Dredging is a fundamental activity necessary for navigational purposes, with two main types of dredging project, CD and MD (UKMarinesac, 2018).

2.2.1 Maintenance Dredging The Port of London Authority classifies MD as the periodic excavation of sediments from existing berthing pockets, swinging moorings and navigation channels. MD provides safe depths of water for vessels to navigate or for construction and operational projects (PLA, 2018).

Figure 4: Heron Construction’s Mesenge flattop barge carrying out MD in the Rangitoto Channel to provide safe water depths for vessels using the Port of Auckland in New Zealand.

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2.2.2 Capital Dredging CD is new civil engineering works by means of dredging virgin soils. Works may consist of the dredging of harbour basins, canals, deepening of existing waterways and channels (EUDA, 2018).

Figure 5: Royal Boskalis’ Manu-Pekka and Magnor backhoe dredgers carrying out CD for Graham Lagan Joint Venture on Siemen’s redevelopment of Green Port Hull in England.

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2.3 The Importance of Dredging

“Dredging is the foundation of almost all maritime infrastructure projects and addresses a broad range of society’s economic, social and environmental needs.” (IADC, 2018). Management of sediment balance is necessary to maintain navigation channels, protect coastlines, guard against rising sea levels and materials for building products (Brils et al, 2014). The UK are heavily dependent on maritime trade. It is important that ports, harbours and navigation channels counteract natural sedimentation and maintain depths allowing safe access for vessels (Vivian et al, 2010) & (NOAA, 2017). Growth in populations around coastal areas, rising sea levels due to global warming and increased vessel sizes, result in the need for land reclamation, CPW, CD and MD projects (FMI, 2017). In comparison to transportation on land, waterborne transportation is more environmentally and economically viable. The majority of ports do not possess sufficiently deep navigation and access channels to accommodate vessels. As a result, CD projects are a necessity to form access channels, turning basins and waterside facilities. These water-based facilities will accumulate sediment and require periodic MD to ensure safe transportation of vessels (IADC, 2018).

2.4 Legislation Regulating the Sea Disposal of Dredged Material

The disposal of waste in the sea has been an issue for some time, legislation has only recently acknowledged its importance. In the UK, the sea disposal of DM is governed by licence under Part 2 of the Food and Environmental Protection Act (FEPA). The act controls placement of material into UK waters below mean high water springs (MHWS). FEPA considers various international conventions such as Page 18



the ‘London Convention’, ‘London Protocol’ and the ‘OSPAR Convention’ to protect human health and the marine environment (MEMG, 2003). The 1972 London Convention is considered the starting point for dredging and DM disposal legislation (CEDA, 2009).

INTERNATIONAL AGREEMENTS & CONVENTIONS Abbreviations

Title

Year of

Year of

conclusion

entering into force

London

Convention on the Prevention of

Convention

Marine Pollution by Dumping of

1972

1975

1996

2006

1992

1998

Wastes and Other Matter London

Protocol to the Convention on the

Protocol

Prevention of Marine Pollution by Dumping of Wastes and Other Matter

OSPAR

Convention for the protection of

Convention

the Marine Environment of the North-East Atlantic

Table 4: Lists international agreements and conventions created to govern the sea disposal of waste & DM (Van den Eynde et al, 2013).

Legislation frameworks comprise of international regulations such as EU Directives, which are subsequently translated and enforced by national authorities (CEDA, 2009).

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EUROPEAN DIRECTIVES Abbreviations

Title

Year of

Number

conclusion Habitats

Directive on the conservation of

Directive

natural habitats and of wild fauna

1992

43

2000

60

2008

56

2009

147

and flora Water

Directive establishing a framework

Framework

for Community action in the field of

Directive

water policy

Marine

Directive establishing a framework

Strategy

for Community action in the field of

Framework

marine environmental policy

Directive

(Marine Strategy Framework Directive)

Birds Directive

Directive on the conservation of wild birds

Table 5: Lists European Directives created to govern the sea disposal of waste & DM (Van den Eynde et al, 2013).

2.5 Dredged Materials & Sea Disposal

DM management is a worldwide problem (Karacoban & Onal, 2017). Disposing DM at sea has been common practice from the late eighteenth century, coinciding with the arrival of the steam dredger. Disposal gained momentum with the introduction of self-propelled bottom dumping hopper barges during the mid-nineteenth century. Disposal sites were selected due to convenience, with little consideration given to impacts and were often located close to the dredge site (MEMG, 2003). DM disposal is the last phase of the dredging process (Pullar & Hughes, 2009). Perceptions of DM were negative, with DM classified as waste once lifted off the seabed (DAERA, 2016). Past practices saw the majority of uncontaminated DM Page 20



disposed of at sea in dedicated disposal sites, seabed depressions or for the creation of artificial islands (Bray et al, 1997). However, 90% of DM from navigation dredging are unpolluted, undisturbed natural sediments, ideal for BU (Samarasnghe, 2015). In 2005 CEDA conducted a study, estimating 10% of DM is BU, with 30% sustainably relocated within the aquatic system (CEDA, 2010). The majority of DM from harbour and estuary dredging projects are dumped at sea (OSPAR Commission, 2010). Resulting in a lost opportunity to use the DM for CPW or habitat enhancement projects (Ausden et al., 2018). DM constitutes approximately 80-90% of all materials disposed of at sea (Kleverlaan, 2015). The sea disposal of DM may result in physical changes to the environment, with suspended sediments upsetting primary production, filter feeders and benthic communities (OSPAR JAMP, 2009).

Chemical Disturbance Increased Nutrient Imput

Enhanced Sedimentation (Smoothering)

Increased Turbidity

Change In Sediment Structure Enhanced Suspended Particulate Matter

Figure 6: The main environmental effects of sea disposal of DM (OSPAR JAMP, 2009).

1.2 million wet tonnes of DM were annually dumped at sea by Ireland, between 1997-2006 (Sheenan et al, 2009). DM accounted for 73% of the total volume of

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material dumped at sea. Almost all of the maintenance DM was dumped at sea and 56% of capital DM, with 44% of capital DM used for BU (Sheenan et al, 2009).

Capital Dredging Volume Disposed, 44%

Volume Reused, 56%

Maintenance Dredging Volume Reused 1%

Volume Disposed 99%

Volume Disposed

Volume Disposed

Volume Reused

Volume Reused

Figure 7: Volume of CD & MD material disposed of at sea by Ireland & the volume of DM put to BU between 1997 & 2006 (Sheenan et al, 2009).

Volumes disposed of by Ireland are insignificant compared to other European countries. The UK disposes of 25-50 million wet tonnes of DM (Vivian et al, 2010). A volume varying between 80-130 million dry tonnes of DM was disposed of in the North-East Atlantic Sea and North Sea between 1990-2007. Almost 100% of this material derived from the dredging of ports and fairways such as Hull, Zeebrugge, Rotterdam, Bremen, etc (Van den Eynde et al, 2013).

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Amounts of DM (Tonnes Dry Weight) 140 120

Millions

100 80 60 40 20 0 1990

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

Year

Figure 8: The amount of DM disposed at sea in the Marine Environment of the North-East Atlantic Ocean from 1990 to 2005, volumes range between 80 million to 130 million tonnes and correlate to dredging activities (OSPAR Commission, 2010).

France, Germany and Belgium are major contributors to the volume of DM disposed of in the OSPAR Region of the North-East Atlantic Ocean. Germany, France and Belgium dumped 27.775, 24.402 and 10.660 million dry tonnes of sediment respectively (Van den Eynde et al, 2013). In Germany and Holland, the majority of DM is uncontaminated and is relocated within the water system (SedNet, 2002).

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Amounts of DM (Tonnes Dry Weight) 16 14

Millions

12 10 8 6 4 2 0

Year

Figure 9: Represents the amount of sediment in dry tonnes, disposed of by Belgium in the Belgium area of the North Sea (Van den Eynde et al, 2013).

The dredging industry has recognised the need to reduce amounts of DM disposed of at sea, but volumes are increasing. In 2017 the OSPAR Commission carried out an assessment of DM disposed of in Western Europe, between 2008-2014. During that time, in excess of 1,000,000,000 tonnes of DM was disposed of in the Marine Environment of the North-East Atlantic Ocean (OSPAR Work Area, 2017). 99% of the DM disposed of at sea originated from navigational dredging projects within local harbours, channels and turning basins (OSPAR Work Area, 2017).

Page 24



Figure 10: Shows the total amount (in million tonnes) of DM disposed within the OSPAR Martine Area per country, between the period of 2008 and 2014 (OSPAR Work Area, 2017).

Large volumes of DM being disposed of at sea are an issue in Australia, with its economy and society depending DA to keep ports and harbours operational. DA contribute to severe pressures on the marine environment, with 90 million m³ of DM disposed of at sea between 2011-2015 (State of the Environment, 2016). Although the disposal sites for the dumping of DM are relatively small in size, large areas of the Australian continental shelf are affected by the resuspension and relocation of sediments (State of the Environment, 2016).

Page 25

Volume of Disposal (Million m³)



100 90 80 70 60 50 40 30 20 10 0 North East

South East

South West

North West

Australia

Region 2006

2011

2016

Figure 11: Highlights the volume of DM disposed of at sea across Australia in 2006, 2011 & 2016 (State of the Environment, 2016).

Accurate records were not kept prior to 1972 in relation to sea disposal of DM. Experts estimate 38 million tonnes of DM were disposed at sea by America prior to 1972, with 13 million tonnes of this material considered to be CDM (USEPA, 2017). Awareness of the potential hazards associated with disposal of waste at sea, resulted in the USA, Europe and large percentages of the international community introducing legislation to eliminate the sea disposal of contaminated waste, minimise the environmental impact and control the amount of DM disposed of in the ocean.

Page 26


2.6

Environmental

Issues


Relating

to

The

Sea

Disposal of Dredged Materials

Disposal of DM is a well-managed process, governed by licence and control systems, but there is much to learn in regards to how the marine environment is impacted, especially how the dredging process influences its physical, chemical and biological characteristics (OSPAR JAMP, 2009). Whether dredging actually results in an impact on the marine environment depends upon a number of combined factors such as, sediment characteristics, dredging techniques, frequency, duration and magnitude of DA (Vivian et al, 2010) & (OSPAR JAMP, 2009). DA have the potential to negatively affect the marine ecosystem, habitats and species (OSPAR, 2009). The effects of DA can be described as bottom-up or topdown causes. Bottom-up causes result in primary changes to the physical nature of the water column and influence the health of the biosystem. While top-down effects fish, birds, marine mammals, fisheries, recreational activities and amenities (MEMG, 2003).

Figure 12: Dredging phases & the potential environmental impacts of dredging, sediment transportation & sea disposal (Manap & Voulvoulis, 2014).

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DA lead to the destruction of habitats, resuspension of sediments and increased turbidity, this may cause the release of nutrients, transportation of CDM, reduced visibility, oxygen depletion, decline of flora and fauna (OSPAR, 2009). Zones exposed to systematic MD are likely to have depleted/impoverished seabed faunas, this is not the case for areas not subjected to regular dredging (Vivian et al, 2010). Environmental issues that occur during dredging comprise of effects on marine creatures owing to increase turbidity in the water column, effects on benthic organisms when the sediments settle on the seabed, biotic impacts resulting from the mobilisation of contaminants, organic material, bacteria, viruses, nutrients and a reduction in dissolved oxygen. Physical changes to the seabed may result in turbidity plumes, which could destabilise and increase sediment transportation (Vivian et al, 2010).

Figure 13: Potential environmental impacts of dredging (Elliott & Hemingway, 2002). Ecosystems have been depleted by human contact over the last half century, resulting in losses to biodiversity (IADC, 2013). Page 28



Sediment extraction may disturb and disperse CDM into the water column, change topography of the seabed, create dredging plumes, exposing both fishes and benthos to contamination. Disposal of sediments can cause a range of issues from bioaccumulation, exposure to contaminants, increased turbidity and physical changes to the sediment characteristics at the disposal site (Manap & Voulvoulis, 2014).

Figure 14: Details the potential environmental impacts of dredging (Elliott & Hemingway, 2002).

Dredging may have physical, chemical and biological impacts, with long-term or short-term effects. The impacts could manifest themselves in a variety of forms; 

Deterioration of marine ecosystems,



Reduction in socio-economic aspects of the sea,



Interference with legitimate users,



Reduction in aesthetics (MEMG, 2003).

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ENVIRONMENTAL IMPACTS ASSOCIATED WITH DREDGING & DREDGED MATERIAL DISPOSAL AT SEA Substrate removal & thus habitat and species removal Alteration of bottom topography & hydrography, thus destroying of local habitats & the risk of direct physical/mechanical stress to species present Spread of sediments & contaminants in the surroundings of the dredging site; Alteration of sediment composition, i.e. of substrate characteristics in the surrounding area, resulting in a change of the nature & diversity of benthic communities, e.g. decline of individual density, species abundances or biomass Local resuspension of sediments and increase of turbidity Transport of sediments, particularly of finer fractions, and possibly adsorbed contaminants from the dredging area to other (possibly more sensitive) areas, there resulting possibly in an increase of contaminant concentrations Release of nutrients, increase in eutrophication Introduction of new species Consumption of oxygen, generally limited to the direct surroundings of the dredging site. In tidal waters, no enduring impact is to be expected Impact on pelagic and benthic organisms (e.g. decrease of primary production due to reduced transparency of the water column, smothering) may occur, but is less important at the dredging site Mixing of interstitial water with sea water, turbidity plumes and resuspension may change the physical/chemical equilibria, with a potential to release contaminants into the water phase (remobilisation), especially in suspensions of anoxic silty sediments, to enhance the bioavailability and ecotoxicological risk of the already present (background) contaminants (e.g. heavy metals), and to chemical or biochemical changes of contaminants;

Table 6: Lists the numerous potential environmental impacts of dredging, sediment transportation and sea disposal activities (Manap & Voulvoulis, 2014).

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2.7 Dredged Material as A Resource

The Port of Oakland (USA) conducted a survey finding the industrial and commercial communities have little to no enthusiasm to use DM as a resource. DM is not considered as a resource as it is unable to compete economically with traditional primary resources. Expense incurred, energy usage and CO² emissions during DM treatment are all contributing factors.

Investment is required to

develop technologies that produce cost-effective and ecological methods for treating DM (Brils et al, 2014). DM can reduce pressures on primary resources such as quarried rock. DM has a negative image due to its unattractive properties for construction and the public perception that it damages the environment (Brils et al, 2014). The negative perception of DM can be seen in the UK, where 40-50 million tonnes is dredged each year with 1% BU (Bolam & Whomersley, 2005). There is the perception that DM is an unwanted and unclean soil that serves no purpose. DM are predominantly clean sediments and can be reused effectively for engineering and environmental enhancement projects (IADC, 2009). Sediments form an integral part of the ecosystem and should remain there if DM’s quality meet requirements (SedNet, 2002). DM is not waste, it is a significant source of sediment and environmental/economic resource (Murray, 2008) & (Harrington & Smith, 2013). Using DM as a resource is not yet common practice (Brils et al, 2014). While DM is underutilised around the world, in 2003, Japan proved that DM can be successfully BU, utilising 90% across a variety of projects (PIANC, 2009) & (CEDA, 2010). Most countries have a number of constraints making BU less attractive when compared with traditional disposal e.g. costs, public perception, finding markets, complicated legislation and regulations (CEDA, 2010). Legislation should not classify DM as a waste (Murray, 2008).

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Not all DM are resources, but a significant amount of DM types can be BU. They are; 

Rock,



Gravel & Sand,



Consolidated Clay,



Silt & Soft Clay,



Mixed Materials (Murray, 2008).

CDM can be classified as a resource, greater planning is required and the cost to treat the CDM may increase (IADC, 2009). The majority of sediments can be BU after it is dredged, the defining factor is how the DM is managed. Finding alternative uses for DM and classifying it as a resource, requires careful evaluation of its environmental acceptability, technical feasibility and economics (USACE, 2015). DM are increasingly seen as a resource material (Krause & McDonnell, 2000). CDM can be repurposed via an assortment of technologies, such as; 1. Contamination separation, 2. Contamination destruction, 3. Contamination reduction & 4. Contamination stabilisation (Krause & McDonnell, 2000). Separating CDM can be achieved by implementing desorption or vitrification methods. Both methods separate contaminants from sediments but are energy intensive and expensive (Krause & McDonnell, 2000). Contaminated destruction is achieved by adding chemicals to the DM to target and eliminate specific contaminants (Krause & McDonnell, 2000). Contaminant reduction may be accomplished by sediment washing and solvent extraction (Krause & McDonnell, 2000). Stabilisation of CDM is designed to immobilise contaminants within DM, which can be used for reclamation or for building materials (Krause & McDonnell, 2000).

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2.8 Dredged Material Management

DA must be conducted in an efficient, environmentally and cost-effective manner (USACE, 2015).

BU of DM encourages alternative and innovative DM management practices, minimises environmental impacts linked with disposal of DM and reduces cost, with the possibility of re-using material widely regarded as waste (Harrington & Smith, 2013).

The following considerations must be reviewed when considering DA; 

Long-term planning of dredging projects,



Selection of equipment and contractor,



Implementation of environmental controls,



Identification of CDM and treatment,



Characterisation of sediments and development of BU/disposal plan,



Creation and implementation of a monitoring system for both the dredged area and placement site,



Management of CDM to maximise storage (USACE, 2015).

To encourage BU of sediments, DM Management must review the supply and demand strategy. There is an opportunity to BU of DM in the building sector as products, in the agricultural sector and on infrastructure projects. Better coupling is required between supply and demand. DA should be linked with sediment demand. Geographical supply and demand were successfully implemented in Holland (Brils et al, 2014). A major hurdle to BU of DM is communication between supplier and end-user. Supply and demand should be concurrent ensuring DM availability and with tests conducted to certifying material suits the placement area (Ausden et al., 2018), (Murray, 2008) & (IADC, 2009).

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It is essential that sediment characteristics are identified at the early phases of a project to establish the physical, biological and chemical properties of DM. Early assessment of DM characteristics can be achieved by implementing SI, comprising of sampling, testing and analysis plan of the dredge and placement area (Harrington & Smith, 2013).

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2.9 Site Investigation – Sediment Sampling, Testing & Evaluation

2.9.1 The Importance of Site Investigation SI is an integral component of marine base construction/dredging projects. SI uses modern sampling techniques and software, to eliminate unforeseen circumstances and mitigate or implement control measures for risks (IADC-SI, 2015). Although significant investment may be required, SI are the first step towards a successful project and can prevent future delays and cost escalations (Johnson, 2005). A comprehensive understanding of the physical characteristics of both the dredging and DM placement environment result in effective, financially and ecologically successful projects (USACE, 2015).

What types of soils and material are present? Are these materials dredgeable? What type of equipment and plant will be needed? What will the wear and tear on plant be? Is the stipulated budget feasible for the works? How can the material be used beneficially? Can the DM be stabilised for reclamation purposes?

Figure 15: Questions answered by a detailed site investigation (IADC-SI, 2015) & (Maher et al, 2013).

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2.9.1.1 Detailed Site Investigation SI may not be necessary, in the case of MD, data may already exist, meaning a desktop study could be sufficient. Where limited information is available a preliminary investigation is required (OSIG, 2004). CD projects always require in-depth SI. Land reclamation projects require detailed investigation for the dredge and reclamation location (IADC-SI, 2015). Accurate site and geotechnical investigations assist project teams to match sediments with certain characteristics for a particular BU option (Krause & McDonnell, 2000).

Benefits arising from SI are;

Selection of dredging equipment Determine dredging methology Select the dredge location Calculate dredge volumes and production rates Identify the physical & chemical characteristics of sediment Establishing a project budget, bid, plan & project completion Early identification of risk

Figure 16: Areas in which a site and geotechnical investigation may assist a project team, adopted from Geotechnical Investigations for Dredging Projects (Johnson, 2005).

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Table 7 shows information collected from SI.

Bathymetric

Detection of

Geological &

Hydromorphic &

or

Seabed

Geotechnical

Meteorological

Topographic

Obstructions

Investigation

Data

Survey

(UXO, Wrecks & Boulders

Single beam

Side Scan

Geophysical

Hydraulic Data

survey

Sonar

Seismic

Water Levels,

Reflection Seismic,

Tides,

Refraction Seismic,

Currents

Geoelectric Survey Multibeam

Multibeam

Sampling Methods

Sediment

survey

Sonar

Borehole,

Transport/Turbidity

Vibrocore, Jet Probe, Grab Sample, Test Pit Land survey

Magnetometer

Testing

Meteorological

Survey

Laboratory Tests,

Data

In-situ Tests,

Waves,

Cone Penetration

Ice,

Tests

Fog Seismic Data Earthquake Risk, Tsunami Risk

Table 7: Chart showing the information required from a site investigation (Van t’ Hoff et al, 2012).

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Inadequate SI result in issues which ultimately lead to failure of a dredging and reclamation project (Johnson, 2005).

Inaccurate and incomplete geotechnical site information.

Incomplete Scope.

Poor production.

Inappropriate Selection of equipment and methodology.

Cost and budget overruns.

Exposure to risk. Inaccurate production estimates. Inaccurate cost estimates.

Late schedules. Poor quality. Poor performance. Disputes and claims. Incomplete projects.

Figure 17: Shows the potential consequences of an inadequate site investigation (Johnson, 2005).

SI provide the project team with an advantage, increasing the potential of a successful project for the contractor and client (Johnson, 2005). Accurate and complete geotechnical site information.

Complete Scope. Appropriate Selection of equipment and methodology. Low risk. Accurate production estimates. Accurate cost estimates.

Accurate production rates. Accurate budget. Accurate scheduling. Good quality. Good performance. Successfuly complete projects.

Figure 18: Shows how adequate site investigation lead to successful dredging and reclamation projects (Johnson, 2005). Page 38



To ensure an accurate SI, three aspects of ground examination are essential to accumulate the required data.

Bathymetric Surveys

Geological & Geotechnical Evaluations

Environmental Assessments

Figure 19: Three main aspects of ground examination required to collect adequate data during a site investigation (IADC-SI, 2015).

SI characterises sediments by in-situ sampling, testing and analysis (Harrington & Smith, 2013).

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2.9.2 Bathymetric Survey Bathymetric Surveys determine the seabed profile and water depts over the dredged area (USACE, 2015).

Depth Contours

Cross Sections

Isobaths Curves

Digitised Grids

Figure 20: Information produced as a result of Bathymetric Surveying (IADC-SI, 2015).

Echo Sounders are commonly used to conduct bathymetric surveys, reaching depts of 5000m. Sea conditions impact quality, as does the surveyor’s skill (IADCSI, 2015).

2.9.3 Geological & Geotechnical Investigations Geotechnical testing plans are created at the beginning of projects to aid with the identification of BU schemes. Due to the individual characteristics of each project, the options for BU require innovation and possibly bespoke methods, therefore it is important to consult the stakeholders to determine the geotechnical testing requirements (USACE, 2015).

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DM characteristics are site specific, due to the nature of the material, it is important to customise surveying and sampling plans to suit each project (Harrington & Smith, 2013). Testing frequency depends on the quantity of DM, sensitivity of the environment and level of contamination (IMO,2005). Comprehensive and effective SI comprise of a number of boreholes/core samples evenly distributed across the dredge area, to establish characteristics, volume and location of materials (Johnson, 2005) & (Maher et al, 2013). Physical samples are collected from the dredged area, which are subsequently tested and evaluated to determine; 

Particle size distribution,



Soil consistency/water content,



Organic content,



Settlement & consolidation,



Shear strength,



Plasticity,



In-situ density,



Mineralogy,



Particle specific gravity



Permeability etc. (IADC-SI, 2015).

Once characteristics are known, the project team can decide which equipment and techniques can be implemented to extract and transport the material, determine disposal or BU options, levels of contamination and treatment required (IADC-SI, 2015), (USACE, 2015) & (Harrington & Smith, 2013).

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There are four factors that determine the testing regime, sampling methods and BU;

Volumes to be dredged & reused

Sediment charateristics & benefical use options

Contamination level of sediments & how they can be stabilised or treated

Beneficial reuse location, capacity required & purpose

Figure 21: Factors that determine the sampling and testing methods when considering DM for BU projects (Maher et al, 2013).

2.9.3.1 Sampling Methods

The marine licence application process for dredging, disposal, alternative use or joint dredging and disposal applications, requires the applicant to undertake sampling to inform their application. (DEFRA, 2016). As dredging projects are conducted across a range of jurisdictions, it is essential that the project team consider all the regulatory requirements to ensure that the project meets the demands of the regulatory agencies involved. Care is required when planning the sampling and testing program, as the initial sampling and testing period can be time consuming and costly (Maher et al, 2013). If sufficient investment is not made during SI, the project will be exposed to higher risk resulting in delays and cost escalations.

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There are several techniques that can be used during a site investigation, as seen in Table 8;

Seismic & geophysical methods: Subbottom profiler, parametric echosounder, chirp system, sparker & boomer Side scan sonar Jet probes

Rotary drilling

Shell & Auger boring Vibrocores

CPTs

SPTs

Van Veen sampling Laboratory testing

ADVANTAGES

DISADVANTAGES

Useful to establish the likely geology over a large area. Will assist to set-out a borehole grid and fill in detail between borings

An expert is needed to choose best combination of available systems for the job at hand. Careful interpretation of data is needed. This can often lead to discussion. Especially vulnerable if only slight changes in strata occur (i.e. no distinct boundary between layers). Not suitable for assessing soil properties. No other purpose. Accuracy doubtful: May identify boulders rather than top of rock. Operated from platform. Weather delay while repositioning. Expensive. Assessment of conglomerates or weathered rock is critical. Usually operated from platform, otherwise prone to ship movements. Not applicable for rock or conglomerates. Maximum penetration some 3 to 5 metres. Only suitable for sandy clayey soils. Slightly disturbed samples. Not applicable for rock or conglomerates. No samples.

Detection of bottom surface & objects. Relatively easy & quick method to establish point readings for top of rock. Best method of obtaining core samples of intact rocks in in-situ conditions. Method employed in order to obtain representative & undisturbed samples. Frame lowered to seafloor. Relatively low costs. Continuous reading of cone pressure & shear along penetration length. Indication of soil type in cohesive & sandy soils. Commonly used worldwide, yielding an indication of relative density. Combination with sampling. Low cost. Establish required engineering values (either classical soil mechanic parameters or special dredgeability indicators). A welldrafted laboratory programme greatly enhances the value of the in-situ investigations.

Precise execution according to standard test often compromised. Large scatter in relation of relative density to SPT. Not to be used in cemented sands. Disturbed sample, from top of seabed. Often time-consuming. Selection of samples not to be underestimated. Same is true for proper reporting.

Table 8: Comparison of SI Techniques (Kinlan & Roukema, 2010). Page 43



Surveys should reflect site specific conditions. It is necessary to conduct a survey of the dredge area, determining the amount, location and depth of each sample. “Core samples should be taken where the depth of dredging and expected vertical distribution

of

contaminants

suggest

that

this

is

warranted.

In

other

circumstances, grab sampling will usually be sufficient” (OSPAR Commission, 2014). Table 9 indicates the number of sample stations needed to achieve representative results, assuming sediments are evenly distributed across the dredging area (OSPAR Commission, 2014). RECOMMENDED NUMBER OF SAMPLE STATIONS VOLUME DREDGED (m³)

NUMBER OF SAMPLE STATIONS

Up to 25 000 3 25 000 ‐ 100 000 4 – 6 100 000 ‐ 500 000 7 – 15 500 000 ‐ 2 000 000 16 – 30 >2 000 000 extra 10 per million m³

Up to 25 000 3 25 000 ‐ 100 000 4 – 6 100 000 ‐ 500 000 7 – 15 500 000 ‐ 2 000 000 16 – 30 >2 000 000 extra 10 per million m³

Table 9: Indicates the number of sample stations required in relation to the dredge volume (OSPAR Commission, 2014).

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Figure 22 shows steps to followed when conducting a pre-dredge survey;

Figure 22: Steps for developing a pre-dredge survey (Harrington & Smith, 2013) & (PREMIAM, 2011). Page 45



2.9.3.2 Core Sampling Core samplers are a steadfast method for gathering sediment samples appropriate for assessing the geotechnical properties of bulk sediments (Maher et al, 2013). Samples are strategically taken and used to demonstrate sediment characteristics across the full depth of the dredging prism. They are used to develop strategies in relation to BU of DM, which can be based on sediment grain size (Maher et al, 2013). Identification of sediment types throughout the dredge area, assists with selecting dredging techniques, equipment and BU. Common methods to extract samples are;

Vibra-Corer

Gravity Corer

Piston Corer

Figure 23: The three most common methods used to extract core samples from a proposed dredge area (Maher et al, 2013).

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2.9.3.3 Vibra-Corer Vibra-corers are used on consolidated and unconsolidated materials.

Figure 24: Diagram shows an electronic Vibra-Corer used to collect sediment samples for dredging projects (USGC, 2018).

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2.9.3.4 Gravity Corer Gravity corers are used on unconsolidated sediments.

Figure 25: Shows a Gravity Corer used to collect sediment samples for dredging projects (Virtuel, 2018).

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2.9.3.5 Piston Corer Piston corers are used on consolidated and unconsolidated materials.

Figure 26: Shows a Piston Corer used to collect sediment samples for dredging projects (Boes, 2015).

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2.9.3.6 Grab Sampling Grab sampling is fit for extracting sediments of the seabed surface, they are unable to reach depths exceeding 300mm.

Figure 27: Typical grab used to collect sediment samples for dredging projects (IndiaMart, 2018).

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2.9.4 Sampling of Stabilised Materials Once materials are evaluated and additives mixed with DM to form a structural fill, the material requires sampling and testing ensuring it preforms as per design. The number of samples will be determined prior to the commencement of stabilisation. Samples may be taken from the stabilisation process on a barge, truck or stockpile.

2.9.5 Sediment Characteristics Evaluating DM’s physical, chemical and biological characteristics is important, it allows informed decisions when selecting BU options (Harrington & Smith, 2013). 2.9.5.1 Physical Testing Physical testing provides an understanding of the sediments engineering properties and highlights any underlying environmental issues (Harrington & Smith, 2013). PHSYICAL CHARACTERISTICS OF DREDGED SEDIMENTS Particle size distribution Water content Engineering properties Permeability characteristics Atterberg Limits Organic content

Table 10: Physical characteristics of DM to be identified during physical testing, adopted from (Sheehan & Harrington, 2012) & (Harrington & Smith, 2013).

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Table 11 shows requirements from physical testing; PHSYICAL INFORMATION Amount of material Anticipated or actual loading rate of material at the deposit site Sediment characteristics preferably by grain size analysis (laser or sieving methods) or exceptionally on the basis of visual determination (i.e. clay/silt/sand/gravel/boulder)

Table 11: Information required from physical characterisation of dredged sediments (OSPAR Commission, 2014).

2.9.5.2 Chemical Testing Sediments are exposed to contamination from natural and human sources. Chemical analyses of sediments identify the presence of contaminants and potential environmental impacts (Harrington & Smith, 2013). CHEMICAL CHARACTERISTICS OF DREDGED SEDIMENTS Organic Content (e.g. plant, animal, and microbial residues) Ionized hydrogen (H+) Salinity and soluble salts Nutrient content (Nitrogen and Phosphorus) Potassium, magnesium and Sulphur Contaminants (e.g. TBT, PAH’s, heavy metals) Radioactive substances

Table 12: Physical characteristics of DM to be identified during chemical testing (Harrington & Smith, 2013) and (PIANC, 1992).

Chemical testing may not always be required if existing information is available (OSPAR Commission, 2014). The information presented in Table 13 becomes available as a result of chemical testing;

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CHEMICAL INFORMATION Major geochemical characteristics of the sediment including redox status Potential routes by which contaminants could reasonably have been introduced to the sediments Industrial and municipal waste discharges (past and present) Probability of contamination from agricultural and urban surface runoff Spills of contaminants in the area to be dredged; Source and prior use of dredged materials (e.g., beach nourishment) Natural deposits of minerals and other natural substances

Table 13: Information required from chemical characterisation of DM (OSPAR Commission, 2014).

Chemical analysis of DM is crucial in determining BU options. The presence of contaminants such as TBT’s, DBT’s, PCB’s and PAH’s could dictate BU options and result in additional treatment to DM (Harrington & Smith, 2013). 2.9.5.3 Biological Testing Biological analysis of DM is a costly exercise, only undertaken when relevant information cannot be gained from physical and chemical testing (Harrington & Smith, 2013) & (OSPR Commission, 2014). Biological testing determines the level of toxins in sediment and assists in the identification of possible impacts on local species (OSPR Commission, 2014). BIOLOGICAL TESTING Toxicity bioassays Toxicity Identification Evaluation (TIE) Biomarkers Microcosm experiments Mesocosm experiments Field observation of benthic communities

Table 14: Information required from biological characterisation of DM (OSPAR Commission, 2014).

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Characterisation of DM establishs Action Levels to identify disposal & BU options with minimal impact on the environmental. Action Levels have an impact on licensing decision (Deara, 2016). ACTION LEVELS Below Action Level 1 In general, contaminant levels in DM below Action Level 1 are of no concern & are unlikely to influence the licensing decision. Between Action Levels 1 & 2 DM with contaminant levels between Action 1 and 2 requires further consideration and possible further testing before a decision will be made. Marine and Fisheries Division will decide on which disposal site is most suitable to receive the DM if the application is successful & inform the applicant within the licence document. Above Action Level 2 DM with contaminant levels above Action Level 2 is considered unsuitable for sea disposal. This most often applies only to a part of a proposed dredging area & so that area can be excluded from disposal at sea & disposed of by other routes, e.g. landfill.

Table 15: Action Levels & description (Deara, 2016).

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2.9.4 Environmental Impact Assessment

Environmental Impact Assessments (EIA) are used to determine possible impacts on the environment. In recent years EIA have become common practice on dredging projects (Bray 2008). An EIA will assist in determining;

The presence of conaminates at the dredge site or reclamation area

Flora & fauna that could be impaceted

Effects of fill material on the environment

Figure 28: Shows information that can be made available to the project team by conducting an EIA (IADC-SI, 2015).

EIA’s can develop greater understanding of dredge environments prior to commencement of projects (CEDA, 2013). EIA identify BU options, it should be used to determine if the project plan is environmentally acceptable. If not, it can assist with amending the plan to make it acceptable (IADC, 2008). Environmental monitoring may establish if DA are having an impact on the environment and allow for the installation of control measures (IADC, 2010). EIAs allow reviewing of meteorological, hydraulic and sediment transportation information.

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EIAs assist with three activities that reduce the adverse effects on the marine environment; 1. Identifying, controlling and minimising sources of sediment contamination, 2. Maximising the utilisation of DM for BU 3. Reducing the volume of sediment to be dredged by implementing Best Environmental Practices (OSPAR Commission, 2014).

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2.10 Overview of Equipment & Techniques Used During Dredging & Material Stabilisation Projects

A dredge is defined as “apparatus used for an excavation activity that is carried out at least partially or fully submerged underwater, with the purpose of gathering up bottom sediments and disposing of them at a different location” (DCS, 2018). SIs/EIAs can be used to determine sediment characteristics, water depths, tidal range,

sea

conditions,

dredging

volumes,

schedules

and

accessibility

(StartDredging, 2018). Accurate assessment of projects requirements at inception, determines dredgeability of sediments, production rates and equipment selection (Kinlan & Roukema, 2010). The achievement of environmental/financial targets on dredging and reclamation projects depends on equipment and stabilisation method selected. Dredgers excavate sediments from the bottom of a waterbody by either hydraulic or mechanical extraction. DM transportation is conducted by hydraulic or mechanical transportation (Vlasblom, 2003). The prime movers of DM are; Cutter Suction Dredge (CSD), Backhoe Dredge (BHD) & the Trailer Suction Hopper Dredge (TSHD) (Uelman, 2015).

2.10.1 Types of Dredging Equipment The main classifications of dredger are; mechanical, hydraulic and hydrodynamic dredgers (Vivian et al, 2010). The selection of equipment depends on the dredge volume, sediment characteristics and transportation demands (EUDA1, 2018).

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2.10.2 Hydraulic Dredgers Hydraulic dredgers utilise a centrifugal pump to lift loose material from the seabed (Vivian et al, 2010), the main movers are; 

Plain Suction Dredger (PSD),



CSD,



BHD,



TSHD (Vlasblom, 2003),



Reclamation Dredger (RD),



Barge Unloading Dredger (BUD) (EUDA1, 2018).

2.10.2.1 Plain Suction Dredger PSDs are the most basic suction dredger, consisting of a pontoon that supports a pump, suction and offloading pipe (Vlasblom, 2003).

Figure 29: Plain Suction Dredger used for the hydraulic extraction of cohesionless sediment (DredgeYard, 2018). PSDs operate from a stationary position, in shallow waters they are anchored using a spud leg or moorings in deeper waters. PSDs and booster pumps are utilised on reclamation projects, to transport DM ashore via floating pipelines (EUDA1, 2018).

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Figure 30: Shows a booster pump connected to a floating pipeline, to assist with the transportation of dredged material (RoyalIHC, 2018).

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2.10.2.2 Cutter Suction Dredger CSD are either stationary dismountable or a self-propelled vessel with a rotating cutter head (CH) attached to the suction pipe. CSDs extract rock, clay, silt and sand for land reclamation, trench dredging, port construction, MD, coastal defence or river protection projects (BoskalisCSD, 2018).

Figure 31: Graphical illustration of a Jan De Nul Cutter Suction Dredger connected to a floating pipeline (JDN-IADC, 2014).

The CH is rotated over the dredge area in a starboard or port motion using winch wires, the CH breaks into and sucks sediment into the CH (Vlasblom, 2003). DM can be pumped using a centrifugal pump to the shore via floating pipelines or into transport barges (Bray, 2008) & (Vivian et al, 2010). Production rates range from 50,000m³-900,000m³ per week (Uelman, 2015).

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Figure 32: Graphical illustration of the draft of a Jan De Nul Cutter Suction Dredger equipped with rotating cutter head to dislodge cohesive sediments & suction hose located within the ladder for the extraction of DM (JDN-IADC, 2014).

CSDs come with a variety of CH, selection depends on DM characteristics.

Figure 33: Two CHs, the CH on the left is used for extracting clays (Morijn, 2011), while the CH on the right is used for the removal of rock (Everflowing, 2018).

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2.10.2.3 Trailer Suction Hopper Dredger TSHDs are self-propelled hydraulic dredgers and utilise centrifugal pumps to relocate DM from the seabed to hopper barges or reclamation (IADC-TSHD, 2014). TSHDs dredge soft silts, clays, gravels, firmer materials can be dredged but risk pump blockages (Vlasblom, 2003).

Figure 34: Depicts a TSHD with suction tube deployed on the seabed (JDN, 2018).

Figure 35: Shows a TSHD’s draghead attached to the end of a suction tube to remove material from the seabed (JDN, 2018).

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TSHDs are usually equipped with swell compensators helping the vessel to dredge in rough seas. TSHDs contain a hopper that is accompanied with bottom opening doors or valves, allowing sediment to settle and be placed over disposal sites (Vlasblom, 2003).

Figure 36: TSHD using its bottom opening doors to release DM over a disposal site (JDN, 2018).

DM is pumped ashore using floating pipelines or the vessel can unload material by pumping threw a high-pressure pump located at the front of the ship (rain bowing) (Uelman, 2015).

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Figure 37: Shows a TSHD placing DM by rain bowing (RoyalIHC-TSHD, 2018).

2.10.2.4

Reclamation

Dredger

&

Barge

Unloading

Dredges RD and BUD transport DM from hopper barge to shore, for land reclamation or storage. BUDs are fitted with suction pipes and heavy-duty dredge pumps releasing high-pressure jets of water (EUDA1, 2018). The suction pipe is lowered into hopper barges, the high-pressure water jets mixes DM and facilitate the suction process (EddyPump, 2017).

Figure 38: BUD suction pump with high-pressure jets (Damen, 2018).

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Figure 39: BUD sucking DM from a hopper barge & pumping ashore (Damen, 2018)

2.10.3 Mechanical Dredgers Mechanical dredgers utilise mechanical excavators/equipment to release sediment from the seabed and bring it to the surface for disposal (Vivian et al, 2010). The main types; 

Bucket Ladder Dredger (BLD),



Grab Dredger (GD) &



BHD.

2.10.3.1 Bucket Ladder Dredge BLDs are stationary mechanical dredgers, containing a ladder in the centre of a U-shaped pontoon, it carries a chain of buckets that act as a conveyor belt, removing sediment from the seabed below, returning to the top of the ladder with buckets of DM that is guided to a shoot and disposed of in barges (Vlasblom, 2003).

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Figure 40: Graphical representation of a BLD (MadeInChina, 2018).

Figure 41: DEME Group’s Adriatico BLD (BalticShipping, 2018).

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2.10.3.2 Grab Dredge GDs are stationary or self-propelled dredgers, they employ clamshells to dredge material from the seabed. Clamshells are attached to mechanical excavators or draglines. GDs mainly operate in harbours; however, the dragline can operate in open waters. DM is loaded into hopper barges and transported for disposal or unloading (Vlasblom, 2003).

Figure 42: Clamshell attachment used by Heron Construction Co. Ltd. on the Messenge barge for dredging of soft clays, silts and sands.

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Figure 43: Heron Construction’s Messenge barge with Hitachi EX700 mechanical excavator using clamshell attachment to load hopper barge while performing maintenance dredging at Auckland’s Rangitoto Channel.

GDs are easily relocated and can transport the DM to reclamation or storage sites. Production rates depend on water depth, material characteristics, clamshell size and distance to the relocation site (EUDA1, 2018). GDs remove cohesive silts, clays and unconsolidated sands, they are deployed on MD projects (Vivian et al, 2010).

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Figure 44: East Marine’s Bestla Grab Dredger with 10m³ clamshell attached to line (EastMarine, 2014).

2.10.3.4 Backhoe Dredge BHDs are stationary barges, with deck mounted hydraulic excavators that removes DM by pulling the bucket towards the pontoon (Uelman, 2015). BHDs have a dredging depth of 15m-30m (Vlasblom, 2003). Due to the excavation power, BHD are suitable for dredging unconsolidated clays, tills, boulders, rubble, debris, rock, sands, slits and heterogeneous materials. They are used for bulk dredging of a variety of sediments, can be used in hard to reach locations, navigation channels and along quay walls (IADC-BHD, 2014). BHD can dredge with greater precision when compared to other dredgers, easy to move due to the lack of wires and only require a hopper barge for loading (IADCBHD, 2014).

Page 69



Figure 45: Heron Construction’s Kimahia backhoe dredger carrying out capital dredging works for the Port of Napier in New Zealand.

Page 70



Figure 46: Royal Boskalis’ Magnor backhoe dredger carrying out capital dredging works for berthing pockets at Graham Lagan Joint Venture on Siemen’s redevelopment of Green Port Hull in England.

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2.10.4 Hydrodymanic Dredgers Hydrodymanic dredgers transport sediments by means of natural forces. There are two main methods of sedimentary transportation, the first is water injection to agitate the seabed allowing the sediment to be released and travel from the dredge site with natural currents. The second method is ploughing/blading the dredge area, disturbing the sediment on the surface and allowing sediment to be transported using natural forces (Vivian et al, 2010). There are two types; 

Water Injection Dredger (WIJ) &



Underwater Plough Dredger (UPD).

2.10.4.1 Water Injection Dredgers WIJ inject low pressure water into the seabed to agitate sediments, reducing their cohesion and encouraging the sediments to mobilise and travel from the dredge area in a fluid state with natural currents. The use of WIJs is suited to MD projects (Vivian et al, 2010) & (Van Oord, 2014).

Figure 47: Shows a Van Oord WIJ Dredger & a graphic of a horizontal jetting bar positioned over a dredge area (Van Oord, 2014).

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2.10.4.2 Underwater Plough Dredgers UPD consist of a large frame/bar being dragged over the seabed. DM is scraped of the surface and dragged by the blade from the dredge area (Vivian et al, 2010).

Figure 48: Shows a tug boat dragging a blade across a dredge area (DAMEN, 2017).

2.10.5 Dredged Material Processing and Stabilisation It is difficult to deal with DM, due to restrictions in relation to sea disposal and lack of space to process DM for BU. Storage of DM is important, dewatering the DM will result in a reduction in volume and improved geotechnical characteristics (Van Mieghem et al, 1997). It is recommended that DM rests in the hopper barge for 24 hours prior to dewatering, to allow the settlement of suspended sediments. Dewatering improves geotechnical characteristics, handling and reduces the amount of stabilising agent (SA) required (Maher et al, 2013).

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Figure 49: Shows the dewatering process of DM from a hopper barge (Maher et al, 2013). Page 74



Large scale dewatering of sediments can be achieved using equipment such as the Eco-Screw (Oida, 2007). The Eco-Screw removes water from sediment using revolving auger blades while conveying DM. The DM is endlessly transferred via auger blades and compressed to minimise mass (Oida, 2007).

Figure 50: Shows the working principle of a large diameter dewatering plant (Oida, 2007).

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The main additives used to stabilise DM are; Ordinary Portland Cement (OPC), Lime and byproducts from kiln dust. The type of additive use depends on the BU application, characteristics of the DM and final destination of the PDM (Maher et al, 2013).

SELECTION OF STABILISING AGENT Effectiveness in reduction of water content Regulatory requirements & restrictions Processing facility configuration Applicability to a wide range of sediments and chemical contaminants Availability & cost

Table 16:

Factors influencing the selection of stabilising agent for BU of DM

(Maher et al, 2013).

There are two options when treating DM with a high initial water content, that is to add a binding agent by either mass stabilisation-solidification (MSS) or process stabilisation-solidification (PSS) (Makusa, 2015).

2.10.5.1 Mass Stabilisation & Solidification MSS is a soil improvement technology, in which the entire volume of DM is S/S to predetermined

depths

(Makusa,

2015).

MSS

can

improve

geotechnical

characteristics of DM, immobilise contaminants and remain cost-effective (Sharma, 2004). Blending of sediments with a binding agent is achieved by excavator mounted rotary heads and high-pressure grout injection, delivering binder during mixing of DM (Makusa, 2015).

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Figure 51: Hiway GeoTechnical’s excavator with rotary head & high-pressure grout injection hose, preforming MSS at the Southern Pipeline Project in Tauranga New Zealand.

The diameter of rotary head is typically 600 to 800mm, rotation speed ranges between 80-100rpm. DM is stabilised in blocks, dictated by the envelope of the excavator, daily production of up to 300m³ of stabilised sediments (Makusa, 2015), (Massarch & Topolnicki, 2005) & (EuroSoilStab, 2002).

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Figure 52: Excavator with rotary head & high-pressure grout injection hose, used for MSS of DM in a CDF (Wilk, 2015).

DM can be loaded into a hopper barge and positioned for MSS. The DM must undergo dewatering and debris removal. A SA is added to the DM and mixed in the hopper barge (Studer, 2001). Reduced environmental risks and cost are associated with MSS of DM in hopper barges as it eliminates double handling of materials by precluding the movement of DM from one containment vehicle to another. The MSS process alters DM physically and chemically resulting in a structural fill for BU, evading the need and cost of DM disposal (Studer, 2001). It is possible to use this method for in-situ stabilisation by placing the excavator on a barge (Howard, 2012).

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Figure 53: Excavator with rotary head & high-pressure grout injection hose, PSS of DM in a hopper barge (Wilk, 2015).

2.10.5.2 Process Stabilisation & Solidification PSS is an emerging soil improvement technology, that blends binding agents with DM containing a high-water content. Primary binding agents such as OPC are mixed with secondary binders such as FA and granulated blast furnace slag (GGBS). PSS is monitored from a control room, with binding agents added Realtime in relation to the weight of DM in the processing plant (Makusa, 2015).

2.10.5.3 Pugmill Mixing Pugmill systems can be set up to stabilise DM from a barge or from land (Howard, 2012). Pugmill systems can be assembled on a deck of a flat top barge. The pugmill mixers possess the ability to homogenously mix DM with cement to produce an engineered fill (mudcrete) for use in reclamation, formation of seawalls and embankments (HeronConstruction, 2015).

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Figure 54: Heron Construction’s Mesenge Barge processing DM from a hopper barge into mudcrete to create a bund wall at the Port of Auckland in New Zealand.

Pugmill process begins once the first full hopper barge arrives alongside the pugmill plant (Maher et al, 2013). Dewatering and debris removal must be done to prevent damage to the pugmill plant. DM is then unloaded from the hopper barge using an excavator, the DM passes through a vibrating screen where smaller debris are prevented from entering the pugmill plant. The DM is fed to the pugmill system via a conveyor belt where additives are mixed (Maher et al, 2013). The additives are added relative to the weight of the DM on the conveyor belt. The Processed Dredged Material (PDM) can be placed directly into the reclamation, loaded into trucks or stockpiled (Maher et al, 2013).

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Figure 55: Mesenge pugmill barge’s EX700 longreach excavator placing mudcrete at the Port of Auckland reclamation.

2.10.5.4 Pneumatic Flow Tube Mixing (PFTM) PFTM offers numerous benefits when compared to more traditional S/S methods. PFTMs possess a modest footprint, the ability to be mounted on flattop barges, structural geotechnical integrity, and the ability to pump PDM over considerable distances for placement (Power, 2017).

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Figure 56: Illustrates dredged sediments passing through the PFTM and subsequently mixed with a binding agent via turbulence (Stern et al, 2018).

PFTM was developed in the early 2000’s, using silty clay DM for large scale airport reclamation projects in Japan (Stern et al, 2018). Soft sediments are exposed to compressed air, which breaks them down into plugs, the plugs are transported through a pipe via friction and mixed with cement using turbulence (Oota et al., 2009). The PDM is pumped to its final location for placement (Stern et al, 2018).

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Figure 57: Illustrates the PSS of DM using a PFTM (Stern et al, 2018). PFTM have been successfully deployed in Japan, to amend DM for large scale artificial islands. The Central Japan Airport saw maximum production of 1000m³ per hour, cement content ranged from 53 – 87kg/m³ (Maher et al, 2016). PFTM increase processing speeds and uniformity of the stabilised material (Maher et al, 2016). PFTMs help with CDM by reducing leachability during stabilisation, while allowing raw material to become sufficiently flowable to flow through the mixing system. The final product achieves a minimum bearing capacity when cured (Maher et al, 2016).

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A wide range of dredgers has been reviewed in the previous section, Table 17 provides a summary of dredgers and their capabilities.

DREDGER SUMMARY

Sandy

Bucket

Grab

Backhoe

Suction

Cutter

Trailer

Hopper

Dredge

Dredge

Dredge

Dredge

Dredge

Dredge

Dredge

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

Yes

No

Yes

No

Yes

No

Yes

No

No

Yes

Yes

No

Yes

Yes

No

Yes

30

>100

20

70

25

100

50

Yes

No

Yes

No

Yes

No

No

No

Yes

No

Yes

No

Yes

Yes

No

No

No

Yes

Yes

No

No

Yes

Yes

Yes

No

Limited

No

No

Materials Clayey Materials Rocky Materials Anchoring Wires Maximum Dredging Depth (m) Accurate Dredging Possible Working Offshore Transport Via Pipeline Dredging In-Site Densities Possible

Table 17: Summary of dredger capabilities (Vlasblom, 2003).

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2.11 Beneficial Use of Dredged Materials

In the past, it was common practice to dispose of untreated DM in the ocean, causing a multitude of environmental issues. Today, the main options to consider for dredging projects; BU, open and confined water disposal (Millrath et al, 2001). There is always a possibility that DM is contaminated, if this is the case additional treatment may be required. The first step is to deal with contamination at the source (SedNet, 2002) & (Brils et al., 2014). Source control may result in a future reduction in contamination of DM as shown in quality of sediment in the river Rhine, which is continuously improving (ICPR, 2013). Cleaner sediment, will reduce treatment costs, allowing DM products to compete economically with primary resources. Effective source control, requires regulations to control the emission of contaminants and create a sustainable long-term strategy, increasing the availability of DM as a resource, improve quality and reducing treatment costs (Murray, 2008). Treatment options for CDM will depend on several factors, such as DM characteristics and contaminant. A range of treatment options can be preselected in accordance with the characteristics of DM (Bortone et al, 2004).

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TREATMENT OPTIONS FOR CONTAMINATED SEDIMENTS Relocation

Open Water Disposal Injection Dredging

Mechanical Separation

Classification Sorting

Dewatering

Evaporation Mechanical Dewatering

Contaminant Separation

Chemical Extraction Thermal Desorption

Contaminant Destruction

Biological Reduction Chemical Oxidiation Thermal Oxidiation

Contaminant Immobilisation

Chemical Immobilisation Thermal Immobilisation

Disposal

Sub-Aquatic Confined Disposal Upland Disposal

Table 18: Options when considering treatment of CDM (Bortone et al, 2004). Treatment options can be predetermined depending on the characteristics of the DM. Figure 58 shows a number of treatment options for DM types and indicates which are most expensive (Bortone et al, 2004).

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Figure 58: Range of available treatment options for CDM, these treatments can be preselected in accordance with the characteristics of the DM. The figure has a key listing which type of DM can be treated by each method and indicates which methods are most economically viable (Bortone et al, 2004).

2.11.1 Beneficial Usage Options SedNet, defines the term ‘BU’ when “sediments are used for a certain purpose” (Bortone et al, 2004). BU involves the placement of DM for a productive purpose (Millrath et al, 2001). Page 87



BU schemes involve unique engineering challenges that must be met to achieve efficient and cost-effective method of handling materials prior to project commencement (Krause & McDonnell, 2000). DM can be BU for: agriculture, aquaculture, construction, industrial, forestry, erosion control and shoreline stabilisation usages (Siham et al, 2005). A number of BU for DM were developed by the international dredging community. The BU of DM can be applied in three categories; Engineering Uses, Environmental Enhancement & Agricultural/Product Uses (Harrington & Smith, 2013). BU of DM for Environmental Enhancement purposes include: 

Sediment cell maintenance,



Quarry and mine fill,



Wetlands and Uplands habitats enhancement/creation (Harrington & Smith, 2013).

BU of DM for Agricultural & Product purposes include: 

Landfill lining,



Concrete manufacture,



Road subbase and embankment construction,



Construction products,



Manufactured topsoil (Harrington & Smith, 2013).

BU of DM for Engineering purposes include: 

Beach nourishment,



Offshore berm creation,



CPW,



Stabilisation and

land

reclamation

(Harrington

&

Smith,

2013)

&

(AQUAFACT, 2012).

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2.11.1.1 Wetland and Upland habitats enhancement or creation

2.11.1.2 Wetland Enhancement DM can be BU to restore or enhance wetland, upland, island and aquatic habitats (Welch et al, 2016). The completion of an EIA is essential prior to works, ensuring the correct DM is selected, complementing the habitat and minimising negative environmental impacts (Harrington & Smith, 2013). Wetland habitats are areas where plants and soils survive while they are saturated. DM is used to elevate or expand wetlands by encouraging colonisation of wetland vegetation (Welch et al, 2016).

WETLAND ENHANCEMENT OR CREATION ADVANTAGES

DISADVANTAGES

Environmental benefit with preservation of endangered ecosystems/habitats Restoration of wetland area can alleviate problems associated with flooding, erosion and reduced fish populations.

Substantial physical, chemical and biological testing is required to determine feasibility Assigning an economic value of beneficially using DM for wetland restoration is difficult and often subjective

Table 19: Lists the advantages & disadvantages associated with BU of DM for wetland enhancement & creation (Harrington & Smith, 2013).

2.11.1.3 Island Creation DM has been BU to create terrestrial island/coastal upland for wildlife habitats and recreational areas. Islands are formed by placing sand and silts in a rip-rap, timber cribs, bulkheads or stabilised using vegetation (Miano, 2016).

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2.11.1.4 Upland Enhancement Upland habitats can range from bear soil to dense forest and contain a diverse range of terrestrial species. Irrespective of the condition or position of the upland habitat, it can profit from the BU of DM (USACE, 2015). Consideration must be taken when selecting the upland habitat to enhance or create. An EIA must be completed to determine if the physical and chemical characteristics of DM is suited to the proposed upland habitat, to identify the target species and vegetation which will benefit from the scheme (USACE, 2015).

UPLAND ENHANCEMENT OR CREATION ADVANTAGES

DISADVANTAGES

Adaptability.

Possible public opposition to placement plan and maintenance plans. The development of a biologically productive area at a given site may discourage subsequent placement or modification of land use at that site. Maintenance of some habitats.

Improved public acceptance.

Creation of biologically desirable habitats Elimination of problem areas. Low-cost enhancement or mitigation. Compatibility with subsequent placement.

Long term management of habitats can be time consuming and expensive. -

Table 20: Lists the advantages & disadvantages associated with BU of DM for upland enhancement & creation (USACE, 2015).

Placement of DM at upland habitats is not a costly exercise, minimal effort is required to stabilise DM (USACE, 2015).

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2.11.1.5 Aquatic Enhancement Aquatic habitat enhancement is the development of biological communities on or below mean tide in coastal locations and in permanent water bodies. Aquatic development may include but is not limited to; 

Tidal flats,



Mud plains,



Seagrass meadows,



Clam flats,



Oster beds,



Fishing reefs &



Freshwater aquatic plains (USACE, 2015).

Hydraulic transportation of the DM should be prioritised when possible and feasible, “due to the high efficiencies and low unit cost for large scale projects” (Harrington & Smith, 2013).

AQUATIC ENHANCEMENT OR CREATION ADVANTAGES

DISADVANTAGES

It provides high biological production.

Lack of understanding in regards to application. Careful site-by-site determination, combined with local biological and engineering expertise, is necessary. -

Has a potential for wide application in both coastal and interior waterways. Complements other habitats Provides habitat where none previously existed or had been eroded away or destroyed.

Table 21: Lists the advantages & disadvantages associated with BU of DM for aquatic habitat enhancement & creation (USACE, 2015).

2.11.1.6 Landfill Capping & Liners DM can be deployment in landfill projects, as opposed to sourcing QM and traditional liners. During the construction of landfill sites, there is an opportunity Page 91



to utilise DM as a landfill liner throughout the construction phase, intermediate cover when the landfill facility is in use and as a capping material while sealing. DM is ideal for the sealing of landfill, as fine silts and clays create a material with low permeability (Maher et al, 2013). DM requires moisture conditioning and material compaction when structurally used as a liner. This is not the case when the DM is placed as a capping material or intermediate layer (Maher et al, 2013). Uses for DM during landfill application include utilising the DM as a grading material, by placing it over general fill, it can be used to raise the existing levels of the landfill facility, for future redevelopment (Maher et al, 2013).

LANDFILL CAPPING & LINING ADVANTAGES

DISADVANTAGES

Can provide a less complex & less expensive alternative to bentoniteenriched soil (BES) or compacted clay liners (CCL). Placing, testing and evaluating the DM will be similar to traditional liner materials, thus existing machinery and testing apparatus are appropriate for DM -

Possible stabilisation and grading of DM may be required depending on physical characteristics. Ideally only suitable for DM sourced from consolidated clay

To date reliance on research pilot-type schemes

Table 22: Lists the advantages & disadvantages associated with using DM for lining & capping of landfill facilities (Harrington & Smith, 2013).

2.11.1.7 Road Subbase and Embankment Construction DM use in road subbase construction is one of the main opportunities for BU (Siham et al, 2005). DM is suitable for use as a construction material and a structural fill during road construction (Harrington & Smith, 2013). Fine grained DM can form the Page 92



subbase/embankment of a road/pavement structure if dewatered, placed correctly and compacted. Compaction in layers is required for embankment construction, it is necessary to guarantee stability, minimising deformation and settlement (Yu, 2014). Dewatering is a requirement when utilising DM as a subbase material below the pavement and the subgrade. DM must be of a granular consistency to prevent migration of fines to the base course, allow water to drain and minimise the impact of frosts. Dewatering is a crucial factor when DM is used for the subbase, as it must be at a level that achieves the relative design density (Yu, 2014).

ROAD AND SUBBASE CONSTRUCTION ADVANTAGES

DISADVANTAGES

Offers a range of potential uses in road construction

Fine grained DM requires the addition of a stabiliser, such as lime or cement, to obtain the required mechanical characteristics for the subbase layer. Use of fine-grained DM as a substitute still at experimental stage with pilot road construction in France an example of application -

Contaminated DM may be used in the road sub-base construction. May contribute to providing a sustainable alternative to quarry sourced natural sand/aggregate.

Table 23: Lists the advantages & disadvantages associated with using DM for road & subbase construction (Harrington & Smith, 2013).

DM must be evaluated to determine if additional stabilisation is required to improve its structural properties and detect the level of organic matter/saline present, as they could negatively impact the road performance (Harrington & Smith, 2013).

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2.11.1.8 Concrete Manufacture The basic raw components of concrete are cement, sand, aggregates and water (Harrington & Smith, 2013). DM may be BU in the manufacturing of concrete. DM can be utilised as aggregate (Harrington & Smith, 2013) and cement component of mix (Krause & McDonnell, 2000). Clean DM has the potential to be used as a replacement to fine sand in the concrete manufacturing process (Limeria et al. 2011). CDM could be treated using

Fluidized Bed Treatment (FBT), completely destroys all organic matter within the DM by exposing it to high temperatures through a heating unit and converting it to carbon, methane or hydrogen (Jones et al. 1999). FBT is seldomly used, as it is energy intensive and costly (Krause & McDonnell, 2000). The cement component can be achieved vie a process of Thermal Desorption and is suitable for all types of DM. Cement-Lock is a technology that is used to achieve Thermal Desorption, a rotary kiln is used to destroys all organic contaminates and most metals. The process involves adding propriety modifiers and heating the DM to a temperature of 1400 ͦ. Any remaining metals are locked into the final product, which is a construction grade cement (Krause & McDonnell, 2000).

CONCRETE MANUFACTURE ADVANTAGES

DISADVANTAGES

May provide an alternative to quarry sourced aggregate in concrete manufacture, potentially reducing construction costs Dredged sediment is suitable for use in several types of concrete such as light weight and self-consolidating concrete. May potentially provide a BU for contaminated DM without requiring expensive pre-treatment.

The quantity of aggregate that can be replaced is dependent on the characteristics of the DM. Results for the fined grained component of DM only based to date on results of research work. -

Table 24: Lists the advantages & disadvantages associated with using DM for concrete manufacture (Harrington & Smith, 2013). Page 94



2.11.1.9 Construction Products DM has been utilised to produce products for the construction industry, such as: tiles, brick and blocks (Krause & McDonnell, 2000). There are no adverse effects when 50% of the raw materials are replaced with DM during the manufacture of brick for the construction industry (Mezencevova et al, 2012). There is no reason that DM from rivers cannot be used when producing bricks. Common uses for the blocks are in the construction industry as noise barriers, security walls and building blocks (Krause & McDonnell, 2000) & (Xu et al, 2013). It is important to evaluate the geo-mechanical characteristics of the DM to determine if it is suitable for brick production. Depending on the properties of the DM, it may be necessary to include additives for brick production. Brick production immobilises heavy metals during the firing process (Baksa et al, 2018).

BRICK, BLOCK AND TILE MANUFACTURE ADVANTAGES

DISADVANTAGES

Contaminated DM may be used with contaminants becoming neutralised in the manufacturing process. Selling the DM as a raw material for the brick/ceramic manufacturing industry may provide an income stream.

Consistency of the DM characteristics required for successful brick manufacture. To date only small to medium scale pilot schemes have been undertaken in France and Germany.

Table 25: Lists the advantages & disadvantages associated with using DM for manufacturing brick, block & tiles (Harrington & Smith, 2013).

Significant amounts of DM lack the physical properties to be BU in the construction sector, treatment options are available but costly (Brils et al, 2014).

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2.11.1.10 Manufactured Topsoil DM can be adopted to produce a manufactured topsoil, elevate ground levels, substituted eroded topsoil or enhance physical/chemical characteristics of soil (Yu, 2014). Sediments that are predominantly silts and sands are suited to the growth of vegetables due to drainage, texture and aeration properties. The organic matter contained within DM provides nutrients for vegetables but the presence of heavy metals will prevent BU in food production (Yu, 2014).

MANUFACTURED TOPSOIL ADVANTAGES

DISADVANTAGES

May provide a potential income stream for ports/harbours that produce significant quantities of maintenance DM on a regular basis. Significant research has been undertaken with several projects completed in the U.S. and the U.K. May contribute to reduced organic municipal waste disposal costs as it is used with DM in the manufacture of topsoil Both hydraulic and mechanical dredging can be used

Relies on a market demand for the product near to the point of source Stringent requirements apply to the characteristics of the DM A reliable and consistent supply of suitable organic material is required -

Table 26: Advantages & disadvantages associated with BU of DM for manufactured top soil (Harrington & Smith, 2013).

DM effectively used for manufactured topsoil when the dredging site undergoes regular MD. DM will require adjustment to ensure it contains properties that make it economically favourable and comparable to other marketed topsoil (Harrington & Smith, 2013).

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2.11.1.11 Beach Nourishment Beach nourishment is an option when nourishment does not occur by sediments resuspended and transported via waves and currents. Beach nourishment provides additional protection against erosion and enhances beach profiles (Millrath et al, 2001).

Beach nourishment can also be used to enhance

recreational areas, lessen the impact of storms and prevent flooding. Design of beach nourishment projects can be complex in nature, mainly due to the characteristics of the material, length of shoreline, sediment transportation and wave climate at the intertidal zone (Harrington & Smith, 2013). The gravel and sand portion of DM are suitable for nourishment, the material must be separated ensuring other materials and contaminants are removed (Millrath et al, 2001).

BEACH NOURISHMENT ADVANTAGES

DISADVANTAGES

Helps to prevent localised flooding and control coastal erosion.

Detailed engineering analysis required to accurately assess the local wave climate and beach erosion rates. If dissimilar material (texture, colour etc.) is used from the in-situ natural beach material then the aesthetics of the beach may be negatively impacted.

Facilitates and supports local tourism by maintaining a wider beach area.

Provides a ‘soft’ engineering approach instead of or in conjunction with traditional ‘hard’ engineering solutions such as construction of sea walls and groynes.

-

Table 27: Advantages & disadvantages associated with using DM for beach nourishment (Harrington & Smith, 2013).

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2.11.1.12 Offshore Berm Creation Offshore berms are constructed for CPW and assisting beach nourishment (Harrington & Smith, 2013). Berms are fully submerged and constructed using a variety of DM (Burt, 1996). There are three BU berms; 

Feeder berms,



Hard berms &



Soft berms (Burt, 1996).

Feeder Berms Feeder berms involve the construction of berms from beach quality material in shallow waters. Design allows the sediments to be transferred from the berm to the beach using littoral currents and storm wave actions, reducing the impact of erosion (Burt, 1996). Feeder berms can reduce dredging costs, as berms are usually situated closer to the dredging site than disposal site, resulting in minimised transportation costs (Murden, 1995). Hard Berms Hard berms are formed using rock and solid materials, the material is placed via split hopper barges, creating a parallel structure to the shoreline. Hard berms are a permanent feature and are used to protect the shoreline against erosion. Hard berms encourage wave height to increase, breaking early and reforming at a lower height due to turbulence (Burt, 1996). Soft Berms Soft berms absorb wave energy, they are constructed from softer materials such as clays and silts. Soft berms are positioned in water that is shallow enough to absorbed waves, yet deep enough to avoid wave induced shear stress. Soft berms are suitable in locations with moderate wave action and weak tides (Burt, 1996).

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OFFSHORE BERM CONSTRUCTION ADVANTAGES

DISADVANTAGES

Established international technology

For berms designed to be stable they may yet be prone to erode with the erosion rate dependent on the local wave climate. May not be suitable for locations when conflicting with fisheries, ports, outfalls etc. may arise. Optimum placement area must be located and be sufficiently shallow to mitigate wave effects.

Recovery site and application may be close reducing DM transport costs. Can provide an environmentally acceptable “soft-engineering” solution to coastal protection. May be created by simple discharge of DM from hoppers

-

Table 28: Advantages & disadvantages associated with BU of DM for offshore berm construction (Harrington & Smith, 2013).

2.11.1.13 Coastal Protection Works (CPW) BU of DM for CPW works is common practice. DM is used to form the core of a breakwater and in some cases the outer layer meets the specific design requirements for costal protection (Harrington & Smith, 2013). Ecosystem services such as creating dunes, can provide multiple benefits such as costal protection, recreational areas and water purification, resulting in greater value for money (Rijkswaterstaat, 2013). DM can be pumped as a slurry into geotextile cloth to form Geotubes. The slurry must contain a high volume of solids to fill the geotubes and may require a specialised dredger to pump the slurry at high-pressures. The geotubes are then used as a substitute for the core material in a breakwater, they are stacked into position to form the required shape, wrapped in a layer of geotextile cloth and covered with rock armour. This method can also be used to form the shore side of a breakwater (Sheenan et al., 2009).

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COASTAL PROTECTION WORKS ADVANTAGES

DISADVANTAGES

Versatile technology and relatively simple to implement

Risk of tearing / distortion of geotubes with potential to lead to instability and undermining of coastal structure Generally available in specific sizes which may not necessarily suit a particular application. Customizing may be expensive. Hydraulic equipment is required for geotubes

May provide an environmentally beneficial and economically viable alternative for elements of traditional rubble mound structures Use of geotubes can retain and isolate some forms of contaminants

Table 29: Lists the advantages and disadvantages associated with using dredged materials for coastal protection works (Harrington & Smith, 2013).

2.11.1.14 Sediment Cell Maintenance (SCM) SCM is the placement of DM in a tidal zone to reduce erosion on sand banks, mudflats, saltmarshes and enhance sub-tidal or intertidal habitats (Van der Wal et al, 2010). The removal of DM from a water system could change the morphodynamic structure and ecological function of the system, SCM helps recharge the system (CEDA, 2010). SCM should be conducted using uncontaminated fine-grained DM, while comprising traditional disposal methods with modern soft engineering techniques. The DM must be compatible with the placement site in terms of its physical, chemical and biological properties (Harrington & Smith, 2013). Accurate placement is essential as is the selection of dredger. In most cases a hopper barge is preferable with DM pumped to a pontoon barge for diffuser disposal (Harrington & Smith, 2013).

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SEDIMENT CELL MAINTENANCE ADVANTAGES

DISADVANTAGES

Contributes to maintaining the natural sediment regime of an estuarine system which may be affected by dredging activities. Relatively easy to implement with environmental benefits.

Extensive DM characterisation and monitoring of the local ecosystem must be undertaken to ensure no negative impacts. Likely to require advanced computer modelling and specialist involvement at the design stage.

Subtidal and intertidal habitats can be enhanced for benthic macro-fauna.

-

Table 30: Advantages & disadvantages associated with BU of DM for sediment cell maintenance (Harrington & Smith, 2013).

2.11.1.15 Quarry and Mine Fill DM and CDM can be stabilised and BU as a fill material for abandoned mines/quarries (PDoEP, 2001). Fine-graded DM is ideal as a fill. Consideration must be given to the location of the mines in relation to transportation costs, accessibility for transportation and placement equipment, plus an EIA to determine the impact on the surrounding environment (Harrington & Smith, 2013).

2.11.1.16

Stabilisation,

Solidification

and

Land

Reclamation Land reclamation is one of the dredging sectors main activities, with the BU of DM to create land for industrial and infrastructure purposes (Mustafa, 2011). Reconstituting DM for land reclamation is an extremely effective BU option. When dredging and reclamation activities are in close proximity, major cost savings can be achieved by precluding of removal and disposal costs. As S/S of DM creates an impermeable material, there is no need for a liner at the reclamation site (Priestley, 1995).

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S/S technologies marry two technologies, creating a dual process where stabilisation immobilises contaminates and solidification binds DM (USACE, 1993). S/S results in DM with an increased compressive strength, reduced compressibility and decreased permeability. It must be noted that S/S additives and methods are selected in relation to site specific conditions (Makusa, 2015).

LAND RECLAMATION ADVANTAGES

DISADVANTAGES

Reclaimed land can provide an economic incentive for dredging stakeholders where benefits to tourism, ports and industry may be realised. Potential profits to be made from reclaimed/improved land may be substantial. may be less expensive to place the DM in a reclamation area than transport to a disposal site The creation of reclaimed land may be more environmentally acceptable than disposal at sea. -

Final land use of the reclaimed land may be restricted depending on the type of DM used. Reclamation may not be possible where water depths are excessive. Consolidation and drainage are slow, and the final strength achieved may be low Potential land ownership issues must be resolved May require extensive environmental impact analysis.

Table 31: Highlights the advantages & disadvantages associated with using DM for land reclamation (Harrington & Smith, 2013).

Land

reclamations

are

successfully

implemented

for

projects

such

as

airports/airport enlargements, ports/port expansions (Kolman, 2013). Land reclamation can also utilise BU of DM on residential and recreational developments situated on waterfronts and environmentally deployed on CPW (Kolman, 2013).

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LAND RECLAMATION OPTIONS TYPE OF DREDGED MATERIAL

COMMENTS ON RECOMMENDED LAND RECLAMTION USAGE

Coarse material (rocks/gravels)

Finer grained material (sands/gravels)

Finer grained material (sands/gravels)

Load bearing capacity allows supporting heavier loads. Minimal pre-treatment required before placement of DM. Used for industrial sites or to accommodate roads/railways. Requires longer time to drain and consolidate. Shear strength achieved may be low thus allowable imposed loads may be limited. Recreational uses only e.g. parks. Requires longer time to drain and consolidate. Shear strength achieved may be low thus allowable imposed loads may be limited. Recreational uses only e.g. parks.

Table 32: Land reclamation options for varying types of DM (Harrington & Smith, 2013), (Sheehan, 2012) & (Chen & Tan, 2002).

The main concerns with land reclamation projects are; equipment selection, placement logistics, sourcing, location and volume of DM (Harrington & Smith, 2013).

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2.11.1.2 Beneficial Use Hierarchy

DM can be used on a variety of BU schemes. However, usage of DM for BU depends on sediment type and the practicability of projects. Table 33 provides an overview of DM and BU options.

DREDGED MATERIAL SEDIMENT TYPE DREDGED

ROCK GRAVEL SAND CLAY/SILT MIXTURE

MATERIAL USE OPTIONS CONSTRUCTION MATERIALS 1

Road Foundations

X

X

X

X

X

2

Replacement Fill

X

X

X

X

X

3

Dikes

X

X

X

X

4

Mounds

X

X

X

5

Noise/Wind Barriers

X

X

X

6

Land Reclamation

X

X

X

7

Land

X

X

X

8

Stabilisation

9

Sealing of CDFs

10

Capping of Disposal

X

X

X

X X

X

X

X

X

X

X

X

X

X

Sites & Landfill 11

Capping of Contaminated Sediments

12

Rehabilitation of

X

Brownfield Sites

Table 33: Site specific material selection for engineering use (Murray, 2008).

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While there are many BU options, there is an order of preference for selecting BU methods, as shown in Table 59 (Sheehan, 2012) & (DEARA, 2016). Sustainable relocation is be considered as the preferred option (Murray, 2008).

Table 59: BU Hierarchy, showing the preferred order of use (Sheehan, 2012).

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2.12.0

Stabilisation

of


Dredged

Material

for

Reclamation

Raw dredged materials have poor engineering properties and often require treated by adding pozzolanic binding agents (Yu et al, 2016). Using lime and lime containing coal combustion products (CCPs) e.g. spray dryer ash (SDA) and circulating fluidised bed boiler (CFB) in the stabilisation of DM prevents leaching of contaminants. During the stabilisation of DM, lime immobilises heavy metals such as lead, zinc, cadmium and barium through the process of pozzolanic hydration. Pozzolanic hydration is a chemical reaction that allows DM to gain strength and durability when mixed with lime products (Beeghly & Schrock, 2009). Adding lime kiln dust (LKD), coal fly ash (FA) and SDA to DM, make it possible to process DM into a structured fill for use in construction. The structural fill must have a Liquid Limit (LL) that does not exceed 45%, a Plastic Index (PI) less than 20, with an Unconfined Compressive Strength (UCS) beyond ~35% and California Bearing Ratio (CBR) above 8 (Beeghly & Schrock, 2009). Stabilisation using Pozzolanic or Sulfo-Pozzolanic reaction produces sufficient backfill material for reclamation projects e.g. the Pennsylvania AML Reclamation, which backfilled abandoned mines and reclaimed acidic contaminated soils used to stockpile waste coal gob (Beeghly & Schrock, 2009). The Port of Turku in Finland, has been contaminated by Tributyltin (TBT) from boats and vessels treated with anti-foul paints. EU Life Environment and the Port funded a pilot scheme to dredge CDM from the River Aura and stabilise DM for the filling of the Pansio harbour lagoon (STABLE, 2009). Between 2006- 2009 approximately 50,000m³ of DM was dredged, stabilised and placed in the Pansio harbour lagoon. An aim of the project was to stabilise DM to prevent leaching of TBT and minimise the environmental impact. Ramboll Finland Oy designed a binder that stabilised the sediment resulting in minimal environment impact (STABLE, 2009).

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Two methods of stabilisation were used to place treated sediment into the lagoon and create reclamation. The first method of stabilisation was PSS and second MSS (STABLE, 2009).

Sediment dredged with Environmental Clamshell & Realtiime Dredge Monitoring System Dredged material transported by barge the stabilisation plant. Dredged material removed from barge and loaded into stabilisation plant using an excavator The dredged material was mixed with cement and fly using pressure feeders , a screw mixer and a drum mixer The stabilised dredged material was transported from the stabilisation plant by truck and placed in the lagoon Figure 60: Procedure used for PSS of CDM at the Port of Turku (STABLE, 2009).

Sediment dredged with Environmental Clamshell & Realtiime Dredge Monitoring System Dredged material transported by barge the stabilisation plant. The dredged material was mixed in the barge using a excavator with attached rotary mixing head and high pressure grout injection hose The dredged material was mixed with cement and fly using pressure feeders , a screw mixer and a drum mixer The stabilised dredged material was transported from the stabilisation plant by truck and placed in the lagoon Figure 61: Procedure used for MSS of CDM at the Port of Turku (STABLE, 2009). Page 107



MSS was developed in Finland and used for road construction. In 1996, MSS was adopted to stabilise DM to construct a container terminal in the Port of Hamina, Finland (Lahtinen et al, 2014). MSS is a feasible solution to the issue of CDM that meets technical, economic and environmental requirement while immobilising contaminants, it has been implemented in major port developments throughout Europe (Lahtinen et al, 2014). Material mixed by PSS was more effective compared to MSS, as PSS provided a homogeneous mix of binder and sediment, MSS produced less uniformed results (STABLE, 2009). In-situ mixing of DM was performed at the Port of Valencia in Spain. As with most reclamation projects, cement had been found to be the preferred additive. It must be noted that price may be reduced by adding secondary SA (Druijf, 2016). It is possible to add SA in quantities that water content is below the liquid limit, due to cement binding with water, resulting in increases in the liquid and plastic limits. At a higher cement content, the increase in plastic limit stalls and the liquid limit decreases (Druijf, 2016). The main factors to reviewed when considering in-situ stabilisation of DM;

1

•As DM has very slow self-weight consolidation, the high-water content of the material poses a problem.

2

•The low undrained shear strength of DM causes it to be useless for industrial purposes when no further action is taken.

3

•The rates at which stabilised DM can be deposited are quite low when compared to common dredging disposal rates.

Figure 62: Factors to review when considering in-situ stabilisation of DM (Druijf, 2016).

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In-situ mixing at the Port of Valencia, involved the placement of material in a lagoon, allowing the DM to dry sufficiently forming a crust of 0.5m deep across the surface. The crust provided a working platform for stabilising plant. Figure 65 shows the process used to perform in-situ stabilisation of DM at the Port of Valencia (Druijf, 2016).

Stabilise mud with cement using insitu deep mixing, for mud that has to be driven on by machinery within three days, 110 kg/m³ cement was used. After stabilisation and curing of cement vertical drains are installed. Drains are used to remove the water from the material under the stabilised layer, as it has no other method of egress.

Geotextile sheets are then place over the stabilised layer and gravel layer placed upon the geotextile cloth.

Drainage ditches are then formed in the gravel layer, which direct the excess water to wells which in turn pumps the water to the sea.

A preload is then applied to the surface for consolidation of the stabilised material. The over burden is removed once sufficient time has passed.

Figure 63: Procedure used for In-situ stabilisation of DM at the Port of Valencia (Druijf, 2016).

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Figure 64: Depicts a section of a Land reclamation project showing the in-situ method of stabilising for DM used at the Port of Valencia (Burgos, Samper, & Alonso, 2006) & (Druijf, 2016).

MSS has been successfully implemented in Ireland for reclamation purposes and was utilised for stabilisation of CDM to immobilise contaminates (O’Shea, 2017). MSS was used as a structural fill at Dublin Port on the Alexander Basin project. The Alexander Basin project, is a large CD project that consists of the removal of approximately 470,000m³ of CDM (O’Shea, 2017). DM was stabilised ex-situ via a batching plant and used for reclamation of a disused gravel dock. Each project must be considered on its individual merit in regards to the selection of binder for the DM (O’Shea, 2017). To find a suitable binding agent, 9 mixes were tested with varying levels of OPC and Pozzolanic materials to determine which binding solution was most effective in immobilising contaminants such as Nickel and TBT (O’Shea, 2017). The Bantry Inner Harbour Development in County Cork, is another project in Ireland, that successfully stabilised CDM for BU as engineered fill. The project involved the dredging of 40,000m³ of mildly CDM and placement as engineered fill in reclamation. The DM also contained an element of clean granular material,

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which was used to form a bund wall that housed the stabilised engineering fill (O’Shea, 2017). DM was stabilised ex-situ in placement cells, by attaching an injection head on the excavator that added the binder. Due to the mild contamination levels of DM, pozzolanic treatment was not required at the Bantry Inner Harbour Development. Instead four binders were tested using OPC at ratios of 4%, 6%, 8% and 12%, the lower cement ratios achieved sufficient stabilisation and greater cost-efficiency (O’Shea, 2017).

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2.13.0

Economic

Benefits


of

Beneficially

Using

Dredged Materials

New dredging projects have many economic effects on parties directly or indirectly linked to the project. Assigning an economic value to both the project and ecosystem, helps identify if the project will provide benefits to the environment and economy. When the ecosystem has been assigned a monetary value, it can then be compared to the new works (IADC, 2013). Table 34 describes consequences related to new dredging works.

WELFARE EFFECTS Direct Effects Operator Profit earned through service provision by the project operator (Business case). User Users benefits from increased quality/quality of services delivered by the operator (consumer Surplus): e.g. from lower generalised transport costs, better environmental/recreational services, etc. Third Parties Effects for people not directly involved in the project: e.g. pollution and other environmental externalities experienced by residents. Indirect Effects Transportation Consequences stemming from the traffic induced by the Network project: scale-economies/congestion in transport network, pollution, etc. Strategy Impacts indirectly produced on the local economy. Effects Infrastructure investments can contribute to attracting new firms or workers. As the market expands, productivity and competitiveness may soar as consequence of scale of economies, knowledge spill overs, labour pooling, etc. Employment New jobs may be created in a situation characterised by the presences of structural unemployment. Effects on the employment typically involves low-skilled workers.

Table 34: Describes & classifies some of effects that may result from a new dredging project (Gatto, 2014).

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Dredging campaign and related works both positive and negative economic effects, as seen in Table 35.

Operator User Third Parties

Transportation Network Strategy Effects

Employment

WELFARE EFFECTS Direct Effects Magnitude Positive profits for port operators. + Welfare surplus from savings in generalised ++ transportation costs (Container & Chemical Sectors) Negative externalities from rising port activities (Pollution, noise, sound, etc.); costly natural compensation. Indirect Effects Scale of economy & congestion. +/Attracting new firms or workers has a positive influence on the local economy. Productivity & competitiveness may soar as consequence of e.g. knowledge spill overs, labour market pooling, etc. In presence of structural unemployment, new jobs may be created, typically for low-skilled workers.

+

-

Table 35: Describes some of the positive & negative effects that may result from a new dredging project & the magnitude of those effects (Gatto, 2014).

The management team must review all dredging operations, detect methods that increase efficiency, e.g. fitting the dredgers with equipment that encourages precision, resulting in a reduction in over dredging and costs (IADC, 2014). Using DM as a resource may seem a costly option compared to sea disposal. However, there are many BU options that create a Win-Win scenario (IADC, 2009). The majority of dredging costs come from transportation, equipment used and the dredging process itself (Druijf, 2016). The BU of DM is economically viable, especially when considering the costs to transport DM to disposal sites which are usually located at great distances from the dredge sites (Sheehan et al, 2008).

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There may be added cost when comparing BU to sea disposal of DM. Therefore, it is essential to link dredging projects with a second activity, where DM is utilised in an economic and environmentally advantageous manner (Murray, 2008). To establish if a project will be a success in economic terms, the project team should perform a Cost-Benefit Analysis to identify potential social economic benefits of land reclamation and BU schemes (Gatto, 2014).

Figure 65: Cost Benefit Analysis Formulation (Gatto, 2014). The main factors associated with running a productive port development project, are problem identification, social economic benefits and project identification (Gatto, 2014). Page 114



Early identification of contaminants can allow for the development of disposal options. DM not suitable for unconfined aquatic disposal can be a costly if management approaches are insufficient, resulting in costly disposal on site as fill or when transferred off site (Krause & McDonnell, 2000). Using desorption and vitrification to separate contaminants from sediments is an expensive process and energy intensive (Krause & McDonnell, 2000). Thermal desorption of DM and Cement-Lock can produce cement that can be used in the construction sector and sold on for cost plus 40% (Krause & McDonnell, 2000). BU treatment and confined disposal of DM can be a costly option when it is not practicable to dispose DM in the water system (SedNet, 2002). Placing DM in confined disposal facilities (CDF) in close proximity to the shoreline and dredged site increases cost-efficiency and timely off-loading (Krause & McDonnell, 2000). The most efficient transportation methods of DM to CDFs are pumping the sediment as a slurry or off-loading using a clamshell from a barge positioned next to the CDF (Krause & McDonnell, 2000). CSD should be 5 to 10km from the reclamation for economical transport of materials via pipeline. MSS and PSS are cost-effective methods of ground improvement and immobilising contaminants (Makusa, 2015). However, bench tests are required for each project, to determine suitable SA for DM. Once suitable agents are identified, investigations are conducted to determine cost-effective method of stabilisation (Krause & McDonnell, 2000). Stabilising CDM for a substitute of structural fill is a cost-effective BU. The BU of DM minimises operation costs in relation to transportation of QM to site and DM for sea disposal (O’Shea, 2017). Using OPC as the only ingredient to stabilise DM is expensive, requiring 250kg of cement to bind each m³ of sediment. Reducing the amount by replacing it with FA allows adequate binding and contamination immobilisation using only 45kg of cement per m³, significantly reducing operational costs (Lahtinen et al, 2014). FA is cheaper compared to stabilising with cement and is effective for stabilising large quantities of DM, also removes the burden of disposing of the FA (Yu et al,

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2016). Binding agents can result in 50-70% of the cost for the entire stabilisation process (Wilk, 2015). The costs of additives in all registered cases of stabilisation are often more than four times higher than the cost of ordinary sand where sand is widely available. (Druijf, 2016). The Port of Auckland reclamation, Mudcrete was cost effective as a quay wall could be light, due to the bund wall excreting little load. It also reduces the need for lining as mudcrete was of low permeability (Priestley, 1997). The cost of sea disposal must be offset against the costs associated with using primary resource such as QM and treating the DM for using as a liner (Sheehan et al, 2008). Using DM is economical as it reduces the strain on primary resources (CEDA, 2010). In 2009 it was found that getting sands using a TSHD was cheaper than obtaining sands from onshore quarried sources for reclamation purposes (Mostafa, 2011). In addition to BU of DM for reclamation projects, DM can be used in geotubes to save money on using and transporting QM for break waters, by using DM that would otherwise be dumped as sea (Sheenan, Harrington & Murphy, 2009). The use of geotubes is cost-effective as no specialist equipment is required, customised

site

fabrication can

take

place

and

low maintenance

costs

(Shabankareh et al, 2017). Other BU of DM include use for manufactured topsoil, it is most economical when the dredging site undergoes regular MD and is situated close to the placement site. DM requires adjustment to ensure it contains properties that make it economically favourable to other topsoil brands (Harrington & Smith, 2013). Dredging technologies make it cheaper to reclaim land as opposed to redeveloping brownfield sites, but the economic success of the project depends on a number of factors. Land reclamation/Beach nourishment projects have been successfully completed in Florida, Dubai and Australia’s Gold Coast attracting tourists and revenue for the economy (Kolman, 2013).

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FACTORS INFLUENCING THE SUCCESS OF LAND RECLAMATION PROJECTS Removal of unsuitable mud layers Sailing distance to disposal areas Sailing distances to sand borrow areas Costs of dredging licences /permits Depth of the area to be filled Quality of fill material Wave and wind climate Available construction Availability of modern, hi-tech dredging equipment Production capacity of dredging equipment Quality of the contractor Early contractor involvement and partnering with the client

Table 36: Lists the factors that influence the economic success of a land reclamation project (Kolman, 2012).

Seaside tourism is worth 17 billion pounds in the UK (UKNEA, 2011). Habitat creation/restoration benefit from economy of scale (Eftec. 2015) & (Murray, 2008).

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2.14.0 Environmental Benefits of Beneficially Using Dredged Materials

Using DM for reclamation eliminates negative impacts associated with open sea disposal.

When

stabilising

for

reclamation,

replacing

OPC

with

FA

is

environmentally beneficial, due to reduced carbon footprint. During the manufacture of OPC, 0.8 tonne of CO₂ gases are emitted for each tonne of cement (Lahtinen et al, 2014). During stabilisation of DM, lime and cement immobilises heavy metals such as lead, zinc, cadmium and barium, preventing leaching via pozzolanic hydration (Beeghly & Schrock, 2009) & (Priestley, 1997). CDM can be environmentally dredged to remove it from the aquatic system and stabilised for BU as fill for abandoned mines/quarries. Making environmental improvements to both extraction and placement site (PDoEP, 2001). Using DM for BU can reduce the amount of primary resources required during construction or habitat creation, providing products for the construction industry and in cement manufacturing (CEDA, 2010). Geotubes reduces CO₂ emissions by using DM rather than QM, savings depends on size of the geotubes, distance to the DM disposal site and quarry site. The greater the size of the structure the greater CO₂ saving (Shabankareh et al, 2017). DM can be used for ecosystem services such as beach nourishment, creating dunes, providing multiple benefits; CPW, recreational areas, water purification and habitat replenishment (Rijkswaterstaat, 2013), (CEDA, 2010) & (Harrington & Smith, 2013). Natural habitats provide CPW, act as flood defence, absorb and store greenhouse gases (Ausden et al., 2018) & (van der Werf et al, 2015). Salt marsh restoration can prevent the release of carbon into the atmosphere (Alonso et al, 2012). The creation/restoration of habitats could reduce the risk to birds that nest on beaches. Wildlife is under pressure from the expansion of recreational activities around the coast and human interaction (Ausden et al., 2018).

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Dredging has benefits for fish and their habitats by increasing oxygen content, reoxygenation of sediments, resuspension of nutrients and extraction of CDM via environmental dredging (Hopkins & White, 1998) & (IADC, 2014). The sustainable relocation of DM within its own ecosystem is the most environmentally friendly and preferred BU option (Murray, 2008).

2.15 Conclusion

This chapter discussed the issues associated with dredging and sea disposal of DM. It also reviewed the BU options, equipment selection, plus the economic and environmental advantages and disadvantages associated with dredging. The following chapter will discuss the research methodology.

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Chapter 3 RESEARCH METHODOLOGY

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3.0 Research Methodology 3.1 Introduction

The dissertation aims to evaluate the volume of DM disposed of at sea and BU utilised. The intention is to deliver practical resolutions for discarding DM in the aquatic ecosystem.

The objective is to produce procedures to assist with

management decisions relating to the BU of DM, allowing the selection of economic and environmentally attractive option. Particularly interested in shown towards stabilisation of DM for land reclamation projects, plus factors that determine when BU of PDM becomes economic and environmentally viable. This chapter reviews and appraises a range of available research methodologies, explaining the selection of the Mixed Research Method and considerations that were prevalent during the questionnaire design. The chapter explores sources of data, method of data collection, distribution and questionnaire limitations.

3.2 Research Methodology

There are two main research methodologies quantitative and qualitative research. Quantitative research uses closed-ended questions, to collect, analyse and interpret data (Fellows & Liu, 2015). Qualitative research utilises open-ended questions, journals, observations and interviews to collect, analyse and interpret data (Zohrabi, 2013). Mixed research method (MRM) combines quantitative and qualitative research (Johnson & Onwuegbuzie, 2004).

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3.2.1 Quantitative Research Quantitative research is objective in nature and demarcated as an investigation into a social/human issue (Naoum, 2013). Quantitative research is founded upon theory composed of variables or testing a hypothesis, to determine if a theory is true or false (Creswell, 1994). Quantitative research examines a set of particular circumstances that produces an outcome of interest, with dependant variables that can be measured and expressed numerically. In these circumstances, casual interpretations are concluded from observations of experiments or through statistical analysis (Lakshman et al, 2000).

3.2.2 Qualitative Research Qualitative research is subjective in nature, emphasising meanings, rather than numerical data, it often verbally annotates experiences. There are two approaches undertaken in qualitative research; exploratory and attitudinal. Exploratory research develops knowledge of a subject matter, while attitudinal research gauges the opinion of a person towards a subject (Naoum, 2013). “Qualitative research is empirical research where the data are not in the form of numbers” (Punch, 1998). Qualitative research is a multimethod effort, adopting a naturalistic style while focusing on the topic at hand (McLeod, 2008). Qualitative research is conducted while subject matters are in natural settings, endeavouring to make sense of or interpolate singularities in terms of meanings associated with them (Denzin & Lincoln, 1994). The fundamental difference between quantitative and qualitative data is how they are defined, quantitative data is described as numerical, while qualitative is not (McLeod, 2008).

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Differences between qualitative and quantitative research are shown in Table 37.

DIFFERENCES BETWEEN QUALITATIVE & QUANTITATIVE RESEARCH

CONCEPTUAL

QUALITATIVE

QUANTITATIVE

Concerned with

Concerned with

understanding human

discovering facts about

behaviour from the

social phenomena.

informant’s perspective.

METHODOLOGICAL

Assumes a dynamic and

Assumes a fixed and

negotiated reality.

measured reality.

Data are collected through

Data are collected

participant observation and

through measuring

interviews.

things.

Data are analysed by

Data are analyses

themes from descriptions by

through numerical

informants.

comparisons and statistical inferences.

Data are reported in

Data are reported

language of the informant.

through statistical analyses

Table 37: The main differences between qualitative and quantitative research (Minichiello, 1990).

Quantitative research can be used to provide a definitive answer, while qualitative research can provide an observation for a complex subject matter from a limited number of sources (Shuttleworth, 2008).

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3.2.3 Mixed Research Method (MRM) MRM combines the advantages from the quantitative approach and qualitative method, resulting in philosophical assumptions (Johnson & Onwuegbuzie, 2004) & (Creswell, 2009). It was apparent that MRM was necessary to achieve the desired results. A quantitative approach was required to determine DM types, volumes dredged/disposed of at sea. Qualitative research was necessary to deal with the individual nature of each dredging project and identify unique challenges, advantages and disadvantages encountered. Quantitative research is used to prove a definitive answer, the nature of this research required exploration, delving into the subject to pursue fresh insights (Lapan, 2012). MRM required additional time to gain focused results via quantitative research (in relation to dredge volumes and measurable results) (Shuttleworth, 2009). While qualitative research allows the freedom of collating information from various mediums such as: experiments, questionnaires and interviews (Creswell 2009). There are 13 steps to MRM, which occur during research conceptualisation, planning and implementation phases (Collins et al, 2006).

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13 STEPS TO MIXED RESEARCH METHOD No.

Steps

1.

Rationale/purpose for conducting the mixed analysis,

2.

Philosophy underpinning the mixed analysis,

3.

Number of data types that will be analysed,

4.

Number of data analysis types that will be used,

5.

Time sequence of the mixed analysis,

6.

Level of interaction between quantitative and qualitative analyses,

7.

Priority of analytical components,

8.

Number of analytical phases,

9.

Link to other design components,

10.

Phase of the research process when all analysis decisions are made,

11.

Type of generalisation,

12.

Analysis orientation,

13.

Cross-over nature of analysis.

Table 38: 13 Steps of the Mixed Research Method.

MRM was accompanied by a literature review to develop an understanding of the subject matter and allow the development of a questionnaire.

3.2.4 Literature Review To successfully implement MRM for the dissertation, a literature review is necessary to develop an understanding of relevant information (Taylor, 2010). The literature review provides a comprehensive examination and contextualises existing research on BU of DM (Schaeferr, 2011) & (libncsu, 2009). The literature review was performed to review; 

Volumes of DM disposed of at sea?



BU schemes,

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


Economic and environmental advantages/disadvantages associated with S/S of DM for reclamations.

3.2.5 Questionnaire Design This dissertation utilises questionnaires to solicit information from relevant people. The questionnaire was sent to potential participants electronically via email or direct messaging, it was determined that a targeted approach encouraging a speedy response (Shuttleworth, 2009).

The questionnaire and cover letter

explaining the purposes of the research are in Appendix A and B. The rate of response is unpredictable, dependent upon how strongly recipient feels about the topic (Bencivenga, 2012). Questionnaire contain close-ended questions provide the respondent with a set of fixed options, to allow statistical analysis of the results and open-ended questions or both allow the respondent to answer the question with a substantial amount of freedom (Cohen, 2007) & (Coughlan et al, 2007). Additional information can be gained using this method and may assist in gaining a deeper insight into the topic (DeFranzo, 2011) & (Creswell, 2014). Surveys collect data from a target audience, the questionnaire contained a mixture of closed-ended/open-ended and multiple-choice questions (American Society for Quality, 2004). The questionnaire aimed to capture information from Ports, Harbours and dredging professionals, establishing the industries awareness of BU options, while gaining the opinions of experts in relation to the perceived economic and environmental impacts associated with S/S sediments for land reclamation (Naoum, 2013).

3.2.6 Data Sources This dissertation was constructed using information from both primary and secondary sources. Primary sources of information were collected from interviews and questionnaires sent to dredging professional, port and harbour authorities. Secondary sources of data originated from books, journals, research papers,

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webpages, videos, reports and conferences. They were used to produce the literature review and developing an understanding of the topic. Primary sources of information provided a greater depth of insight into the subject and information that had not been found in the texts, provided a link between the theoretical and reality.

3.3 Data Collection Sampling

To successfully collect data, sampling must be taken from a representative selection of the population (Khairie, 2012). To gather relevant information for this dissertation, the population must be determined to identify the audience relevant to the research (MeanThat, 2016). Two main methods of sampling are probability and non-probability sampling. Probability sampling is the ideal method, as the population is known and entire population can be surveyed. In this case the population is unknown, rendering the approach unpractical, therefore a nonprobability approach was implemented (Bencivenga, 2012). The target audience for this research was dredging professional, port and harbour authorities, questionnaire were issued with the aim of gaining a significant rate of response. The survey desired responses from dredging organisations, as they would be able to provide insight into logistical and economic considerations undertaken during BU schemes. Dredging consultants, ports and harbours were surveyed to determine the environmental impacts and gain knowledge regarding the suitability of DM for S/S purposes. The target audience was selected to collect responses from the client, consultant and contractor. Google searches were used to identify major ports across all continents, this was done to eliminate the possibility of selecting a region that implements a particular dredging and BU trend. Dredging organisations and consultants were also selected from a google search or via the authors personal contacts.

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3.4 Data Collection Limitations

The questionnaire encountered a number of obstacles, which resulted in a limited response. The limitations of the questionnaire are; 

Questionnaires were limited to dredging specialist and required knowledge relating specifically to BU of DM.



Questions required feedback that could be deemed as commercially sensitive.



The majority of ports and harbours had a general email address. (There was little to no response).



The rate of response was slow, with a limited rate of response.

The researcher sent questionnaires to ports and harbours, which resulted in two completed questionnaires. A number of dredging professionals were contacted via LinkedIn and posts via LinkedIn groups, this approach produced improved but limited responses.

3.5 Data Analysis

Questionnaires were sent to the target audience in three formats, 1. Microsoft Word, 2. Google Forms, 3. PDF. All answers were entered into the Google Forms for analysis.

3.6 Conclusion

Chapter 4 reviews the data and displays the information collected from the questionnaires in the form of bar charts, graphics and other media. Chapter 5 provides a conclusion and recommendations for future research.

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Chapter 4 DATA COLLECTION & ANALYSIS

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4.0 Data Collection & Analysis 4.1 Introduction

This chapter presents and examines primary information gathered from the “Beneficial Reuse of Dredged Material” questionnaire. The information is both qualitative and quantitative in nature and is presented in numerus formats such as bar charts, graphs, tables and quotes. The questionnaire aimed to attain;

Identify sources of DM,

Examine the volumes of DM disposed of at sea,

Determine the environmental impacts/benefits & costs associated with disposing of DM at sea,

To analyse and identify BU schemes,

To critically appraise current DM management practices,

Identify specialist plant used during the S/S,

Highlight the disadvantages/advantages associated with BU of DM for S/S.

Figure 66: Desired information from the “Beneficial Reuse of Dredged Material” questionnaire.

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The questionnaire was designed to be short in duration and simple to complete, encouraging participation. The questionnaire contained close-ended/open-ended questions encouraging respondents to include qualitative information, while collecting quantitative data. A summary of each question is presented in this chapter, with an in-depth debate exploring findings and relating them to material considered in the literature review.

4.2 Presentation

Presentation of the questionnaire data will be done with the simultaneous research method in mind as opposed to sequential or transformative. The simultaneous method allows quantitative and qualitative method to be presented together (Creswell, 2009).

4.3 Analysis & Amalgamation of Data

Analysing data in MRM is complex, as it requires the researcher to complete proficient analysation of quantitative and qualitative information from the surveys. The results of the collected data from the quantitative and qualitative questions must be integrated+ “in a coherent and meaningful way that yields strong metainferences” (Tashakkori & Teddlie, 1998).

4.4 Respondent Details & Rate of Response

Due to the unique nature of dredging, organisation names and locations were removed from the dissertation to provide an element of anonymity to the respondents.

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Questionnaires were sent to potential participants via email, 117 questionnaires were sent to ports, harbours, dredging organisations and dredging consultants, with a rate of response at 13.67%. An overview of the response rate and breakdown of the organisation types surveyed can be found in Table 39. Initially the rate of response was poor, the author believes this was due to use of general email addresses. After additional research to gain direct contact details and posts to dredging groups on the LinkedIn network, the rate of response improved. Several organisations had responded stating that they did not have the expertise or knowledge in the topic field and they were unable to participate in the survey.

QUESTIONNAIRE DISTRIBUTION ORGANISATION QUESTIONNAIRES TYPE

ISSUED

RESPONSE

RESPONSE

(%)

(No.)

(%)

27

23.07%

7

5.98%

12

10.26%

7

5.98%

78

66.67%

2

1.71%

117

100%

16

13.67%

ISSUED (No.)

Dredging Organisations Dredging Consultants Ports & Harbours Totals

Table 39: Shows the distribution of the questionnaire, plus the type of organisations that were asked to participate in the survey.

The respondents to the questionnaire spanned across five continents, with 43.75% of the participants originating from a dredging contracting background.

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RESPONDENT DETAILS Organisation Type

Port/Harbour

Number of Respondents

Dredging

Dredging

Contractor

Consultant

7

7

2

Table 40: Presents the number of respondents to the questionnaire and, whether they work for a Port/Harbour, dredging contractor or a consultant.

Table 41 shows the response rate from each organisation type.

RESPONSE RATE FROM EACH ORGANISATION TYPE ORGANISATION QUESTIONNAIRES TYPE

RESPONSE

RESPONSE

(No.)

(%)

27

7

25.92%

12

7

58.33%

78

2

2.56%

ISSUED (No.)

Dredging Organisations Dredging Consultants Ports & Harbours

Table 41: Shows the response rate to the questionnaire from each organisation type.

Table 41 shows the highest rate of response came from the Dredging Consultants, with the lowest rate of response coming from ports and harbours. The author believes this is due to the consultants being involved in dredging and BU activities at a higher level, with the port and harbour employees having little exposure to the subject matter.

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The questionnaire begun by collecting the respondent’s details to determine their role in the dredging industry as seen in Figure 67.

Figure 67: Shows the table on the cover page of the “Beneficial Reuse of Dredged Material” questionnaire for the collecting of the respondent’s information.

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4.3 Question 1, Analysis & Findings

QUESTION 1 In the past 5 years, has your organisation been involved in any dredging operations? If so, could you please provide a brief description of your latest dredging projects? ANSWER 1 (Part A) INVOLVEMENT IN RECENT DREDGING PROJECTS Number of Responses

Percentage

Yes

16

100%

No

0

0%

Table 42: Shows the number of questionnaire participants that recently partook in a dredging project. ANSWER 1 (Part B) PROJECT DESCRIPTIONS Dredging Project Type

Number of Respondents Involved

Maintenance Dredging

8

Capital Dredging

11

Habitat Creation/Restoration

1

Environmental Dredging

3

Navigation Dredging

3

Coastal protection

1

Beach nourishment

1

Pipeline Dredging

1

Rock Armour Installation

1

Land Reclamation

1

Sea Disposal

1

Table 43: Lists the type of dredging project & the number of organisations involved in each project type. Page 135



The first part of the question aimed to determine the quality of the respondents. This was of paramount importance to the researcher, providing assurance that the survey participants possessed recent and relevant dredging experience. The second part confirmed the experience of the respondents, while providing a brief description of projects in which their organisation has partaken.

4.3.1 Analysis of Question 1 All 16 respondents, indicated they had recently participated in dredging projects. This was expected by the researcher, as the questionnaire was designed for dredging professionals. The majority of contributors to the survey had suggested they were involved in multiple projects. Interestingly, Question 1 showed that even with a small number of responses to the questionnaire, the organisations had shown diverse experience across a range of projects.

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QUESTION 2 During dredging operations, what volume of dredged material was extracted? Could you please provide a brief description of the characteristics of this material? ANSWER 2 (Part A) Volume Dredged

Number of Responses

(m³)

Percentage of Respondents

0 – 5 million

9

56.25%

5 – 10 million

0

0%

10 – 20 million

2

12.5%

20 – 30 million

0

0%

30 – 40 million

1

6.25%

40 – 50 million

0

0%

>50 million

1

6.25%

No Volume

3

18.75%

16

100%

Provided Total

Table 44: Details volumes extracted by organisations on recent dredging projects.

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ANSWER 2 (Part B) Volume Dredged

Number of Responses

(m³)

Percentage of Respondents

Sand

7

25.9%

Marine mud

3

11.1%

Rock

3

11.1%

Fine silts

1

3.7%

Silts

4

14.9%

Silty clay

1

3.7%

Soft clay

2

7.4%

Stiff clay

1

3.7%

Hard schist

1

3.7%

Organic matter

1

3.7%

Glacial till

1

3.7%

Gravel

2

7.4%

Total

27

100%

Table 45: Details the types of materials dredged and the percentage dredged by each organisation.

The goal of the question was to identify if significant volumes of DM were being extracted on behalf of the respondent’s organisation and to establish a pattern relating to the characteristics of the sediments.

4.4.1 Analysis of Question 2 All respondents signified their organisation were involved in the extraction of significant volumes of DM. However, 56.25% of the respondents indicated that their projects ranged between 0–5 million m³. These results may not provide an accurate representation of dredging volumes, as none of the giant dredging organisations partook in the survey. Resulting in the exclusion of potentially large/mega projects. Page 138



The question revealed organisations had encountered sediments varying in physical characteristics. The range of physical characteristics in the DM shows the unique nature of dredging, suggesting that DA and disposal options must be tailored to each project. This confirms the findings of the literature review, in relation to the need for SI to establish the characteristics of DM allowing a review of environmental acceptability, technical feasibility and economic BU options (USACE, 2015), (Johnson, 2005) & (Maher et al, 2013).

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QUESTION 3 In relation to the extracted sediments, what percentage of the dredged materials originated from maintenance dredging projects? ANSWER 3

Figure 68: Represents the overall percentage of dredged sediments that originated from MD projects. Th questions purpose was to establish whether the majority of DM originated from CD or MD projects.

4.5.1 Analysis of Question 3 The survey showed 23.1% of the respondent’s DA comprised between 0–10% of MD, with the remaining respondent answers evenly spread across the spectrum. Data indicates the bulk of work completed by the respondents was in relation to CD. The OSPAR Commission and Sheenan et al. (2009) suggest that there is a greater chance of CD sediments being deployed on BU schemes.

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QUESTION 4 What percentage of dredged material was disposed of at sea? ANSWER 4 Dredged Material Disposed

Number of Projects

of at Sea (%) 0 – 10%

7

10 – 20%

0

20 – 30%

0

30 – 40%

0

40 – 50%

0

50 – 60%

0

60 – 70%

0

70 – 80%

1

80 – 90%

3

90 – 100%

5

Table 46: Represents the percentage of DM disposed of at sea and the number of projects each percentage is disposed on. Question 4 aimed to determine the percentages of DM disposed of at sea and establish whether sea disposal is the predominant option.


4.6.1 Analysis of Question 4 Several respondents offered percentages for multiple projects, as a result the author decided to focus on the number of projects rather than number of respondents. Overall 43.75% of organisations disposed of 0–10% of DM in the sea, while 12.5% did not have enough information available to provide accurate figures but indicated the majority of DM was disposed of at sea. The remaining 43.75% of Page 141



respondents advised that 75–100% of DM was disposed of at sea. These findings contradict Sheenan et al., (2009) & the OPSAR Commission by suggesting greater volumes of DM are now being BU. However, it is more likely that the limited number of respondents to the questionnaire resulted in the figures being distorted due to the DM being BU on land reclamation projects. A respondent indicated they disposed of 9% of DM in the sea. However, this was done via resuspension using WIJ, allowing relocation of clean sediments within the ecosystem. WIJ can be considered as BU as it stays within the local aquatic system. It is an environmentally friendly, efficient, cost-effective method of relocating sediments, as it removes the need for transportation and treatment (Sheehan, 2012).

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QUESTION 5 Does your organisation consider DM as a natural resource (Contaminated or Uncontaminated), utilising DM for BU to replace other unsustainable resources? ANSWER 5 Number of Responses

Percentage

Yes

12

75%

No

3

18.75%

N/A

1

6.25%

Table 47: Shows the percentage of organisations that considered DM to be a natural resource.

The question intended to gauge organisation’s perception toward DM and discover if it is viewed as a natural resource.

4.7.1 Analysis of Question 5 75% of organisations consider DM as a natural resource, with multiple organisations stating they BU sediments in reclamation projects. The data confirms Krause & McDonnell (2000) theory, that greater volumes of DM are being put to BU. It must be noted that the high percentage of organisations that consider DM as a resource, could be due to the survey being completed by persons with a serious interest in the subject. Several respondents suggested, while they considered DM as a natural resource, BU depended on other factors such as cost, logistical considerations and the cost of treatment for the sediment if it has been heavily contaminated. This may indicate that CDM is not considered for BU due to remediation costs.

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A respondent stated they considered disposing of DM in the aquatic system as a BU option, due to returning natural sediments to their own aquatic environment (Sheehan, 2012) & (SedNet, 2002).

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QUESTION 6 Are

SIs

conducted

to

determine

the

physical,

chemical

&

biological

characteristics of sediments, to explore a suitable BU scheme? ANSWER 6 Number of Responses

Percentage

Yes

12

75%

No

1

6.25%

Project Dependent

3

18.75%

Table 48: Shows whether organisations are carrying out SI to determine if DM has a potential for BU.

Question 6 intended to investigated whether dredging professionals conducted SI to determine the properties of sediments for BU of DM.

4.8.1 Analysis of Question 6 93.75% of respondents conducted SI to determine BU schemes for DM. One participant stated their organisation did not complete SI when orchestrating MD projects. Suggesting MD was being disposed of at sea, which coincides with the theory that 90% of MD sediments are unpolluted, undisturbed natural sediments, and underutilised as a resource (IADC, 2005). Several answers indicated SI were commonly during planning stages of a project to determine characteristics of the DM for BU. However, 18.75% of participants suggested that SI were not taken for every project. Results are promising and show the dredging industry as a whole, is proactive by searching for BU options, as opposed to sea disposal.

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QUESTION 7 Did the analysis of sediments detect the presence of contaminants?

Figure 69: Provides an indication of the percentage of dredged sediments that detected the presence of a contaminant.

Question 7 was designed to establish if SI detected the presence of contaminants in the majority of sediments.

4.9.1 Analysis of Question 7 92.9% of questionnaire participants had detected contaminants during analysis of DM. The discovery of contaminants most likely leads to further treatment costs, logistical considerations and environmental concerns. Ultimately resulting in a reduction of potential BU options. This question shows encountering CDM is common practice and greater source control is required to prevent future pollution of marine sediments (Brils et al., 2014) & (SedNet, 2002). Page 146




QUESTION 8 If the SI did detect contaminates in the sediments, what contaminants were present?

ANSWER 8 Number of Responses

Percentage

13

81.25%

None

0

0%

N/A

3

18.75%

One or More Contaminates

Table 49: Shows organisations are detecting a range of contaminants during SI.

The intention of Question 8 was to develop an understanding of typical contaminants encountered on a dredging project. LIST OF CONTAMINANTS DISCOVERED DURING SI Contaminant Type 1

PCB

2

PAH

3

Heavy Metal

4

Arsenic

5

Copper

6

Lead

7

TBT

8

Mercury

9

Zink

10

Nickel

11

DDT

Table 50: List of contaminants discovered during SI. Page 147



4.10.1 Analysis of Question 8 PAHs, PCBs, DDTs and Heavy Metal appear to be common contaminants, they can enter the aquatic environment via the natural erosion process, wastewater treatment, shipping, manufacturing and agricultural activities (Taylor, 2014). The presences of DDTs, PCBs and PAHs suggests that historical contamination is an issue as these chemicals have been banned for many years, which points to the need for better source control (Brils et al., 2014) & (SedNet, 2002). It also suggests that the literature review was correct, that sediment quality would benefit from environmental dredging and S/S by adding Pozzolanic or SulfoPozzolanic agents to immobilise the contaminant (Beeghly & Schrock, 2009), (Hopkins & White, 1998) & (IADC, 2014).

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QUESTION 9 Once sediment samples were analysed, were the dredged material’s engineering properties examined for possible stabilisation and solidification?

Figure

70:

Shows

the

percentage

of

respondents

that

considered

stabilisation/solidification after samples had underwent analysis.

The question intended to determine if S/S was considered once the DMs physical properties were found to be acceptable.

4.11.1 Analysis of Question 9 50% of respondents stated that S/S had been considered once analysis proved the DM was suitable. The other 50% did not consider the material for S/S. This could be due to the DM not containing the physical attributes required for S/S or there was not space to preform S/S or need for reclamation.

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QUESTION 10 If the dredged material was found as suitable for stabilisation/solidification, were further investigations conducted to identify an appropriate stabilising agent?

Figure 71: Shows the percentage of organisations that further investigated stabilisation/solidification agents for the DM.

Question 10 aimed to discover if organisations led supplementary investigation to identify suitable S/S agents for the DM.

4.12.1 Analysis of Question 10

35.7% of respondents stated that they carried out further investigation for the DM to identify a suitable S/S agent. Suggesting that detailed SI take place at the planning phase of the project, with the aim of BU of DM for S/S.

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QUESTION 11 What percentage of dredged material was utilised on beneficial reuse schemes?

Figure 72: Shows the percentage of DM that was utilised for BU.

Question 11 purpose was to evaluate the amounts of DM utilised for BU schemes, as opposed to sea disposal.

4.13.1 Analysis of Question 11 The questioned showed 61.2% of the participating organisations put between 70– 100% of the DM to BU. Answers propose the organisations surveyed are actively pursuing BU schemes, which does not align with the trends shown by Van den Eynde et al, (2013) and Sheenan et al, (2009), whom suggest that larger volumes of DM are disposed of at sea.

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However, these figures could be inflated by largescale land reclamation projects. Where one land reclamation project could account for 90% of an organisation’s DM across all dredging projects.

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QUESTION 12 As a percentage, how much of the beneficially used dredged material originated from maintenance dredging projects?

Figure 73: Shows the percentage of DM that was utilised for BU that originated from MD projects.

The question sought to answers in relation to the amount of uncontaminated DM utilised in BU schemes or if it was common practice to disposed of at sea.

4.14.1 Analysis of Question 12 A total of 46.2% of the respondents indicating under 10% of DM originating from MD was utilised for BU. The results were as expected, indicating that large volumes of uncontaminated DM from MD are being disposed of at sea (IADC, 2005), (CEDA, 2009) & (OSPAR Work Area, 2017). There is an argument that disposing of this uncontaminated material at sea is a form of BU as DM is reintroduced to the aquatic environment, which is the Page 153



preferred BU option (Brils et al., 2014) & (SedNet, 2002). However, this will still have an impact on the environment where DM is disposed, as resuspension results in the settling of sediments on benthic community.

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QUESTION 13 Please indicate the type of beneficial reuse project where dredged material was deployed;

Benefical Use Schemes 7 6 5 4 3 2 1 0

Organisation Involved In Dredging Projects

Figure 74: Depicts the types of BU schemes and the number of responding organisations participating in each scheme.

Question 13 intended to develop an understanding of the BU schemes that are being worked on by the dredging sector and analyse the data to identify if certain BU schemes are more popular than others.

4.15.1 Analysis of Question 13 The results showed the BU was being utilised across a variety of schemes. With BU of sediments more prevalent for Land Reclamation, Landfill Cover, Beach Nourishment and Recreational Development projects. While 18.18% of the BU Page 155



schemes were Land Reclamation projects, the limited response to the survey makes it difficult to draw conclusions. These figures may not accurately represent what is happening across the dredging sector.

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QUESTION 14 Has your organisation recently completed any land reclamation or port expansion projects? ANSWER 14 INVOLVEMENT IN LAND RECLAMATION/PORT EXPANSION PROJECTS Number of Responses

Percentage

Yes

10

62.5%

No

6

37.5%

Table 51: Indicates if organisations had been involved in land reclamation of port expansion projects. The question seeks to establish whether DM is commonly put to BU in land reclamation or port expansion projects.

4.16.1 Analysis of Question 14 62.5%

of

respondents

suggesting

they

had

some involvement

in

land

reclamation/port expansion projects, which is in line with Kolman (2013) findings, whom suggests that land reclamation projects are very successful around the globe for numerous purposes. For port expansion projects this may suggest that sediments being dredged from inside a port or harbour are being transported short distances from the dredge site to the placement location. Resulting in a reduction in transport costs, minimising the environmental impact on the local aquatic environment, relieving pressures on primary resources such as QM (Priestley, 1995).

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QUESTION 15 During land reclamation or port expansion, were stabilisation/solidification technologies utilised? ANSWER 15 USE OF S/S FOR LAND RECLAMATION/PORT EXPANSION PROJECTS Number of Responses

Percentage

Yes

7

46.67%

No

6

40.00%

N/A

2

13.33%

Table 52: Indicates if organisations had used S/S technologies for land reclamation projects. Question 15 was created to find out if S/S technologies were utilised to treat DM for land reclamation projects.

4.17.1 Analysis of Question 15 46.67% of respondents indicated the use of S/S technologies during land reclamation projects. Two respondents stated that OPC had been used as SA to preform S/S on DM. The answers also showed the utilisation of specialist S/S technologies and methods such as PSS using a barge mounted pugmill system. It was noted that Vibro Compaction, Pre-fabricated Vertical Drains and Sand Surcharging

methods

were

deployed

for

soil

improvement

during

land

reclamation. This suggests that project teams had reviewed management options for DM at an early stage of the project, resulting in the identification of specialist equipment to carry out S/S of DM (StartDredging, 2018) & (DCS, 2018).

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QUESTION 16 Are EIAs conducted to identify potential issues at the dredge site & the BU placement site? ANSWER 16 USE OF EIAs TO IDENTIFY ISSUES AT DREDGE & PLACEMENT SITE Number of Responses

Percentage

Yes

12

80%

No

1

6.67%

Project Dependent

1

6.66%

N/A

1

6.66%

Table 53: Indicates whether an EIA had been conducted for the projects that the respondents had worked on. Question 16 aimed to determine if EIA were common practice across all dredging projects.

4.18.1 Analysis of Question 16 EIA were conducted by 80% of the organisations that answered the question. Findings are encouraging, as it shows a consideration for environmental consequences at both the dredging and placement location. The findings agree with Bray (2008), that EIA are common place and the dredging sector invest in resources to identify risks and opportunities, aiming to minimise their influence on the environment and proactively attempt to create a positive impact.

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QUESTION 17 Are EIAs conducted to identify potential issues at the dredge site & the BU placement site? ANSWER 17 DREDGING EQUIPMENT BASED ON FUTURE BU OF DM Number of Responses

Percentage

Yes

4

26.67%

No

5

33.33%

Project Economics

2

13.33%

N/A

4

26.67%

Table 54: Details if respondent organisations invested in new equipment for future BU projects.

The question attempted to gauge if organisations were investing in plant for future BU of DM.

4.19.1 Analysis of Question 17 The results suggest that investment is limited in relation to acquiring specialist equipment for BU projects. This is most likely due to the lack of demand and economic benefit. Some respondents did indicate that investment had been made but did not expand on their answer.

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QUESTION 18 If your organisation recently carried out stabilisation/solidification of dredged material, please give a brief description of the equipment used? ANSWER 18 DREDGING EQUIPMENT BASED ON FUTURE BU OF DM Number of Responses

Percentage

2

13.33%

1

6.67%

Vibro Compaction

3

20.00%

Hammers, vibracores,

1

6.66%

Hopper Mixing

1

6.66%

PVD Installation

1

6.67%

6

40.00%

Barge Mounted Pugmill Shore based Processing Plant

dosers, vivrators and rollers, dewatering and other dry plants

Machines, Excavators & ADTs N/A

Table 55: Lists equipment used by the respondents to carryout S/S treatment of DM.

Question 18 was designed to ascertain if specialist S/S equipment had been used for the treatment of DM.

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4.20.1 Analysis of Question 18 Responses to the question demonstrated knowledge of several S/S technologies. With two respondents confirmed stabilising DM from a pugmill barge to produce PDM, while another respondent indicated stabilising DM after it was unloaded onshore. Other significant items of equipment used during the S/S process were PVD installing machines, Vibro-Compactors and Dewater Plant. Responses confirmed the use of several technologies are utilised to conduct S/S of DM.

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QUESTION 19 Please give a brief description of any positive and negative environmental impacts that arose during the beneficial reuse of dredged materials. ANSWER 19 ENVIRONMENTAL IMPACTS ASSOCIATED WITH USING DM FOR BU Number of

Percentage

Responses POSITIVE IMPACTS Wet Land/Habitat Enhancement

2

9.52%

Landfill Cover

3

14.28%

Reduced Carbone Footprint

2

9.52%

Reduction in Suspended Sediments

1

4.77%

Immobilisation of Contaminants

1

4.77%

Use for Agricultural Soil Enrichment

1

4.77%

Flood Control

1

4.77%

Environmental Dredging

1

4.76%

Coral Relocation

1

4.76%

Reduced Strain on Primary Resources

1

4.76%

Increased Traffic for Transport of DM

1

4.76%

Resuspension/Turbidity

1

4.76%

Difficult to Get Disposal Permits

1

4.76%

Increased Time & Transport to BU DM

1

4.76%

3

14.28%

NEGATIVE IMPACTS

N/A N/A

Table 56: Details several environmental impacts found on BU projects by the survey respondents.

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Question 19 was designed to highlight environmental impacts that occur as a result of BU of DM.

4.21.1 Analysis of Question 19 Several respondents stated that the projects were indeed positive environmental impacts as they had replenished land, habitats and enriched spoils for agricultural purposes (Rijkswaterstaat, 2013), (CEDA, 2010) & (Harrington & Smith, 2013). Two participants of the survey indicated that reclamation projects had reduced carbon emissions by reducing the transport of material to disposal sites. An added environmental impact was the removal of heavy truck movements through a city centre and while also removing the strain on primary natural resources such as QM (Shabankareh et al, 2017). One respondent stated that the use of EMMPs controlled the environmental impacts, by identifying issues and monitoring during the project. With coral being relocated as a protection measure.

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QUESTION 20 Please give a brief description of any positive and negative financial impacts that arose during the beneficial reuse of dredged materials. ANSWER 20 FINANCIAL IMPACTS ASSOCIATED WITH USING DM FOR BU Number of

Percentage

Responses POSITIVE IMPACTS BU Schemes Are Economically Attractive

1

6.25%

Reduced Transportation Costs

1

6.25%

Reduction on Primary Resource Use,

1

6.25%

Dredged Gravels Sold to Concrete Industry

1

6.25%

BU Cheaper Than Haulage & Landfill

1

6.25%

Beach Refurbishment Attracts Tourists

1

6.25%

S/S Cost Neutral Compared to Disposal

1

6.25%

1

6.25%

BU Scheme Turned Down Due to Cost

1

6.25%

Expensive Permit Costs

2

12.5%

Treatment Cost of DM is Expensive

2

12.5%

Upland Disposal 150% More Expensive Than

1

6.25%

2

12.5%

Resulting in Cost Saving

Distance More Economical to S/S CDM for Reclamation than to Dispose at Licenced Tip NEGATIVE IMPACTS

Sea Disposal N/A N/A

Table 57: Lists a number of the financial influences found on BU projects by the survey respondents.

Page 165



The aim of ‘Question 20’ was to establish if there were any financial impacts as a result of the BU schemes.

4.22.1 Analysis of Question 20 It was proposed that all BU projects were economically advantageous, suggesting they are only selected if financial benefits are present for the organisation. A respondent confirmed that the economic viability is established prior to commencement of the project, which is in keeping with Gatto (2014) advice that Cost-Benefit Analysis is conducted before proceeding with a project. One participant noted that cost-savings had been made in relation to transport cost and by substituting primary resources with DM (Shabankareh et al., 2017). Another respondent found that their organisation could sell gravel from the dredging process to the construction sector. While two participants noted costsaving achieved on disposal. A respondent suggested that the BU of DM that has been utilised for beach nourishment has the ability to generate revenue by increasing tourism, which agrees with Kolman (2013). One participant had found the cost of preforming S/S and using it in a reclamation was cost neutral, this was due to the location of the disposal site. However, S/S of contaminated sediments proved to be economically beneficial.

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QUESTION 21 Did your organisation discover any economic advantages or disadvantages during the stabilisation/solidification of DM for BU? ANSWER 21 FINANCIAL IMPACTS ASSOCIATED WITH S/S OF DM Number of

Percentage

Responses POSITIVE IMPACTS Reclamation Economically Beneficial

1

4.54%

Reduced Transportation Costs

2

9.09%

Reduction on Primary Resource Use,

1

4.54%

Dredged Gravels Sold to Concrete Industry

1

4.55%

Reduced Disposal Costs

1

4.55%

Reduced Reliance on Costly Primary

2

9.09%

1

4.54%

BU Scheme Turned Down Due to Cost

1

4.55%

Over Cautious Client Preventing BU Savings

2

9.09%

S/S Process Is Time Consuming & Increases

2

9.09%

1

4.55%

7

31.82%

Resulting in Cost Saving

Resources Financial Gain NEGATIVE IMPACTS

Cost to Dredge No Financial Gain N/A N/A

Table 58: Details some of the economic advantages and disadvantages found on S/S projects for BU.

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The question aspired to discover if there were any economic advantages associated with selecting S/S of DM over other BU schemes.

4.23.1 Analysis of Question 21 Two respondents noted cost-savings had been made due to reduced transport costs, with additional savings by using the DM as a replacement for primary resources such as QM. However, another respondent states that some clients are sceptical of DM being used in land reclamation projects and prefer QM. This confirms the negative impression of DM as suggested by Brils et al. (2014) & IADC (2005). These results indicate that the industry would benefit from education around DM and its potential usages, as stated by Murray (2008). One respondent observed that the stabilisation process impacted the production rate of the dredging operations, this in turn increased dredging costs.

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QUESTION 22 Please give a brief description of any positive and negative logistical impacts that arose during the stabilisation/solidification of DM for BU. ANSWER 22 LOGISTIC IMPACTS ASSOCIATED WITH S/S OF DM Number of

Percentage

Responses POSITIVE IMPACTS Activities Removed from Critical Path

1

3.57%

Reduced Transportation

6

21.44%

Reduction on Primary Resource Use

5

17.86%

Pugmill Barge Created Efficient Process

1

3.57%

Reduced Disposal Costs

3

10.71%

Time Saving

3

10.71%

2

7.14%

7

25.00%

Method

NEGATIVE IMPACTS Road Transportation of DM Increased Time & Cost N/A N/A

Table 59: Details some of the logistical advantages and disadvantages found on S/S projects for BU.

The purpose of question 22 was to discover if there were any logistical advantages associated with selecting S/S of DM over other BU schemes.

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4.24.1 Analysis of Question 22 The majority of impacts reported are positive. Most advantages related to an overall reduction in transportation costs by either sea or road. It is to be noted that the only economic disadvantage was related to transportation costs, with one respondent claiming the project had been impacted by a poor supply chain in a congested area. Another respondent stated the placement site for upland disposal was in fact a greater distance than the ocean placement site. Two respondents indicated that major cost-savings from the S/S of DM as there was an abundance of sand, which negated the requirement for QM and logistically reduced double handling of material, this agreed with the findings of Shabankareh et al. (2017). This was also the case for a participant whom stated that the use of a Pugmill barge resulted in processing of DM from a hopper barge (Studer, 2001). Interestingly a respondent suggested that using S/S allows the compaction of DM to be done at a later stage and removes it from the critical path.

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QUESTION 23 Did your organisation discover any logistical advantages or disadvantages during the stabilisation/solidification of dredged materials for beneficial reuse? ANSWER 23 FINANCIAL IMPACTS ASSOCIATED WITH S/S OF DM Number of

Percentage

Responses POSITIVE IMPACTS Reduced Transportation

1

7.69%

Reduction on Primary Resource Use

1

7.69%

Efficient Material Handling

2

15.40%

Less Settlement & Damage to Pavements

1

7.69%

Time Saving

1

7.69%

1

7.69%

6

46.15%

NEGATIVE IMPACTS Road Transportation of DM Increased Time & Cost N/A N/A

Table 60: Highlights advantages and disadvantages responding organisations had encountered when carrying out S/S of DM for BU.

The rationale behind question 23 was to determine if S/S brought any advantages or disadvantages when compared to other BU schemes.

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4.25.1 Analysis of Question 23 The response to Question 23 was minimal, the low rate of response is most likely due to the question not being applicable to respondents. However, each person that responded provided multiple examples. This is reflected in Table 60. One respondent found mainly positives from S/S, claiming a logistical advantage in relation to transportation, with reduced tug boat and hopper barge movements. Another respondent also claimed that reduced truck movements were achieved as a result of S/S, which was in keeping with Druift (2016) & Sheenan et al. (2008). However, one participant found mainly negative impacts arising from the use of S/S, stating truck transportation of the treated material was an issue. A respondent suggested that taking the material ashore would have been more advantageous, it is assumed that this would be in relation to transportation and handling costs. A respondent stated that the use of S/S for BU reduced the volume of waste produced, resulting in a logistical advantage in relation to saving space for dealing with the DM. The respondent also found that it removed the strain on QM and encouraged cost savings as a result. A respondent also mentioned the quality of the S/S was advantageous as it reduced settlement in pavements.

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QUESTION 24 Does your organisation implement a process flowchart to assist with beneficial reuse selection? If so please elaborate below. ANSWER 24 USE OF PROCESS FLOWCHART TO SELECT BU SCHEME Number of Responses

Percentage

Yes

7

50.00%

No

5

37.71%

N/A

2

12.29%

Table 61: Details whether or not organisations that participated in the survey use a process flowchart to assist with the selection of BU options for DM.

The question objective was to determine if organisations had developed a set of procedures or guidelines to assist with the management of DM and the selection of BU schemes.

4.26.1 Analysis of Question 24 50.00% indicated that some form of process was in place to assist with the selection of BU options. Two respondents suggested that while there was a process, it ultimately depended on the most economically attractive option. One respondent indicated that the flowchart was mainly based around the characterisation of DM. Although respondents had indicated somewhat of a process was in place, it is likely that the unique nature of each project and characteristics of the DM resulted in detailed SI as suggested by a participant. Numerous factors and scenarios may make it difficult to establish a useful flowchart/guideline to assist organisations in Page 173



the selection of BU options for DM. Each project may have to be reviewed in detail on a case by case basis.

Page 174




QUESTION 25 Did your organisation conduct any public outreach activities for either dredging consent or application for beneficial reuse of dredged material? ANSWER 25 USE OF PROCESS FLOWCHART TO SELECT BU SCHEME Number of Responses

Percentage

Yes

6

46.15%

No

4

30.77%

N/A

3

23.08%

Table 62: Shows whether or not the respondent’s organisations consulted the general public in relation to the BU of DM.

The question aim was to gauge if those involved within the dredging sector were reaching out to the general public to reassure them or educate them on the BU of DM.

4.27.1 Analysis of Question 25 46.15% the respondents did engage with the general public. There is a possibility the other projects did partake in consultation, with the engagement arranged by the client rather than the contractors, as suggested by one participant. Interestingly, one respondent had mentioned that public outreach was always conducted due to EU tendering regulation Another respondent indicated that the general public and NGO were involved in specific issues such as the relocation of corals. With the limited response and answers being split, it is difficult to tell if organisations are being proactive with public engagement. Page 175



4.28 Chapter 4 Conclusion

This chapter reviewed the responses to the questionnaire. The following chapter will discuss the literature review and the questionnaire in the form of a conclusion and suggest future recommendations.

Page 176



Chapter 5 Conclusion & Recommendations

Page 177



5.0 Conclusion 5.1 Introduction

The chapter provides a conclusion on the findings in this dissertation and links them to the objectives of the research. The aim of this dissertation is to provide alternative solutions for the disposal of DM at sea, while establishing viable options available for dredging projects with regards to the BU of DM. The main objectives of this research are;

To examine the volume and percentage of dredged material disposed of sea,

To find out the environmental impacts and costs associated with disposing of dredging materials at sea,

•To analysis the variety characteristics associated with dredging material and their potential for beneficial use,

•To critically appraise currently management practices in relation to management of dredged materials and provide guidance for project team in relation to BU options.

Figure 75: Research objectives.

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After conducting a literature review and analysis of the information received from the questionnaire, it is clear that considerable volumes of DM are still being disposed of at sea. However, it seems that there is a positive attitude toward the BU of DM within the dredging sector, with many opportunities to increase the BU of DM.

5.2 How Can the Beneficial Use of Dredged Materials Be Encouraged?

The results of the questionnaire suggest that the dredging sector is actively pursuing BU options for DM. However, logistics and cost can be a major obstacle. To encourage greater use of BU, legislation should be put in place to force the BU of DM and prevent disposal. Building regulations should also be examined and relaxed to encourage the use of DM within building products (Murray, 2008).

5.3 Are Dredging Professionals Considering Dredged Material as A Natural Resource?

The results of question 5 and Krause & McDonnell (2000), both indicate that the dredging sector consider DM and CDM as a resource. Public perception of DM is usually negative, the dredging sector and government should promote DM as a natural resource that can relieve strain placed upon other primary resources. The introduction of policy at a practical level and greater knowledge sharing to encourage best practice in DM management would assist with attitudes towards DM. Removing the stigma associated with DM, communicating with the general public to emphasis it as a valuable resource and a contributor to sustainable construction are all ways to improve DM usage.

Page 179



5.4 Are Site Investigations Being Conducted to Determine the Physical and Chemical Characteristics of the Sediment to Identify Beneficial Use Options?

The literature review highlighted the importance of a detailed SI to help identify the physical, chemical and biological characteristics of DM. Which would ultimately result in identification of dredging techniques, equipment selection, identify BU options and their viability (Harrington & Smith, 2013), (IADC-SI, 2005) & (Johnston, 2005). The questionnaire indicated that the sector is currently undertaking detailed SI for that purpose and furthermore SI are conducted at the BU placement site to ensure DM is compatible. SI are being combined with EIA to determine of the BU projects are economical and environmentally viable.

5.5 Does Testing Cover the Placement Site for the Beneficial

Use of

Dredged Material

to

Confirm

Compatibility?

The answers provided for question 16 of the questionnaire suggested testing does take place for both the dredging and placement site. These findings are promising and match the opinions of Bray (2008), Harrington & Smith, (2013) and USACE (2015), whom state that testing is required at both locations to confirm compatibility of the sediments with the placement site.

5.6 Are Contaminated

Dredged Materials Being

Considered for Beneficial Use?

The presence of CDM will result in increased costs for treatment or disposal. The first step in the process is to identify and eliminate the sources of contamination Page 180



(Brils et al., 2014) & (SedNet, 2002). The dredging sector is not responsible for the pollution but it is part of our scope of work to tackle the issue. Treatment at the source is more economical than treatment downstream. Cleaning up of hotspots possess the possibility of resuspending the contaminants which could travel with currents. Responses from question 8 and sources of information from the literature review indicate that CDM is considered as a resource (CEDA, 2009), (IADC, 2009), (USACE, 2005) & (Krause & McDonnell, 2000). CDM can be used in the production of cement, construction products or utilised as a structural fill in reclamation projects. In order to get the CDM to an acceptable standard, additional treatment may be required. This will result in detailed SI and bench studies to stabilise the material with other products such as binding agents e.g. OPC or LKD.

5.7 Who is in the Best Position to Encourage Greater Beneficial Use of Dredged Materials?

The dredging sector is in the best position to promote the use of DM in BU Schemes. However, the sector requires assistance from the government and local authorities to develop legislation (CEDA, 2009) & (Murray, 2008).

5.8 What are the Main Beneficial Use Options?

There are many BU options to choose from, a number of BU for DM that have been developed by the international dredging community and fall under three main categories; Engineering Uses, Environmental Enhancement and Agricultural & Product Uses (Harrington & Smith, 2013). The response to Question 13 showed a wide range of BU schemes, with the majority of BU projects falling under the Engineering Use category.

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BU OF DM FOR ENVIRONMENTAL ENHANCEMENT Sediment cell maintenance, Quarry and mine fill, Wetlands and Uplands habitats enhancement or creation.

Table 63: Beneficial Use of DM for Environmental Enhancement (Harrington & Smith, 2013).

BU OF DM FOR AGRICULTURAL & PRODUCT PURPOSES Landfill lining, Concrete manufacture, Road subbase and embankment construction, Construction products, Manufactured topsoil

Table 64: Beneficial Use of DM for Agricultural & Product purposes (Harrington & Smith, 2013). BU OF DM FOR ENGINEERING PURPOSES Beach nourishment, Offshore berm creation, Land Reclamation, CPW

Table 65: Beneficial Use of DM for Engineering purposes (Harrington & Smith, 2013).

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While there are several options for BU the order of preference for DM usage is shown in Figure 76 below;

Table 76: BU Hierarchy, showing the preferred order of use (Sheehan, 2012).

5.9 Is Specialist Equipment Required to Beneficially Use Dredged Material?

In general dredging equipment can be classified as specialist equipment. However, additional equipment may be required for BU. The main specialist equipment found in the literature review and questionnaires include; 

Pugmill Barges (HeronConstruction, 2015),



PFTM (Power, 2017) & (Stern et al, 2018),



Dewatering Plant (Oida, 2007),



Excavator with Grout Injection Rotary Head (Wilk, 2015).

Standard dredging equipment can be used to implement the majority of BU schemes. But as the research has suggested, each project is unique and some specialist equipment may be required e.g. pugmill barges, dewatering plant, PFTMs, pumps etc. It must be noted that the industry needs to remove the amount Page 183



of red tape preventing the use of new technologies to reduce costs and increase efficiency.

5.10

What

are

the

Disadvantages

Logistical

Advantages

and

with

the

Associated

Stabilisation/Solidification of Dredged Materials for Beneficial Use?

The questionnaire and literature review highlighted similar logistical advantages relating to an overall reduction in transportation costs by either sea or road. When the placement site was located in close proximity to the dredging site, the logistics became simple. For example, there was no need to find disposal sites for the material, as it was no longer a waste material, reducing tug boat, hopper barge movements and negating the need to transport primary resources by road (Sheehan et al, 2008). It was also suggested that pairing secondary projects to achieve BU of DM created a more efficient process (Murray, 2008). Stabilising DM also has the advantage of immobilising contaminants and using biproducts from other sectors such as FA & GGBS.

5.11 What are the Main Economic and Environmental Advantages/Disadvantages

Associated

with

the

Beneficial Use of Dredged Materials?

The questionnaire noted cost-savings had been made due to reduced transport, with additional savings by using the DM as a replacement for primary resources such as QM (Shabankareh et al., 2017). The survey indicated that reclamation projects had reduced carbon emissions by minimising the transport of material to disposal sites. An added environmental impact was the removal of heavy truck movements through a city centre. Page 184



It was proposed that all BU projects were economically and environmentally advantageous, suggesting they are only selected if benefits are present for the organisation, which is in keeping with Gatto (2014) advice that Cost-Benefit Analysis is conducted before proceeding with a project. The survey found organisations could sell gravel from the dredging process to the construction sector. While two participants noted cost-saving achieved on disposal. The questionnaire showed that BU of DM that has been utilised for beach nourishment has the ability to generate revenue by increasing tourism, which agrees with Kolman (2013). The survey indicated that reclamation projects had reduced carbon emissions by reducing the transport of material to disposal sites. An added environmental impact was the removal of heavy truck movements through a city centre. EMMPs are used to control environmental impacts, by identifying issues and monitoring during the project.

5.12 What are the main economic and environmental Advantages/Disadvantages

Associated

with

Stabilising/Solidifying Dredged Materials for the Beneficial Use in Reclamation Projects?

The questionnaire also found that the S/S process impacted the production rate of the dredging operations, this in turn increased dredging costs. The questionnaire also found the cost of preforming S/S and using it in a reclamation was cost neutral, this was due to the location of the disposal site. However, S/S of contaminated sediments proved to be economically beneficial s it removed disposal costs.

Page 185



PSS is an emerging soil improvement technology, it brings many advantages, such as the production of a homogenous material and efficient handling of materials (Makusa, 2015). Pugmill systems can be set up to stabilise DM from a barge or from land (Howard, 2012). Pugmill systems can mix DM with cement to produce an engineered fill for use in reclamation, formation of seawalls and embankments (HeronConstruction, 2015).

5.13 What are the Recommendations for Future Researchers?

Recommendations from the author are; 

Increase measures to ensure source control and minimise exposure to contaminants.



Greater investment required for SI, to encourage early identification of BU options (CEDA, 2010).



Greater investment required to deal with CDM,



Legislation adopted to encourage BU and to label DM as a resource, removing any contradictions from existing legislation (CEDA, 2010). DM and CDM is considered as a waste under current legislation and dealt with under other waste types. Separate legislation required is for DM.



Co-ordinate supply and demand of DM (CEDA, 2010) & (Murray, 2008). Where possible, identify the future needs of ports and harbours, e.g. is land reclamation required? If so utilise the DM, reducing transportation costs and strain on primary resources such as quarried stone.



Greater emphases on DM Management.



Identify the risks and opportunities associated with BU of DM and encourage environmental enhancement using DM (CEDA, 2010).



Follow example set by Japan (90% BU) (CEDA, 2010) and the US (80% BU) (Parson & Swafford, 2012).

Page 186


 


Promote better understanding of risks and benefits of using dredged materials (Murray, 2008). Employ best practice to minimise dredging volumes and increase accuracy, by using monitoring and control systems.



Develop new technologies to improve efficiency and costs particularly emerging technologies such as PFTM & Pugmill barges.



Develop dewatering technologies to allow for processing of dredged material on a smaller footprint.

5.14 Future Works

This research is not comprehensive, the assumptions that have been drawn were limited by the sample population, minimal participation in the survey. Therefore, future research may generate additional findings. Overall, the research achieved its main aims and objectives.

Page 187



References

BalticShipping,

2018;

“Adriatic”

[online]

Baltic

Shipping,

https://www.balticshipping.com/vessel/imo/8638932#gallery-2

Latvia

[Accessed

25/02/2018] Alonso, I., Weston, K., Gregg, R. & Morecroft, M., 2012; “Carbon storage by habitat: Review of the evidence of the impacts of management decisions and condition of carbon stores and sources.” Natural England Research Report NERR043 AQUAFACT, 2012; “Dumping at Sea Dumping Site Selection Guidance Note” AQUAFACT International Services Ltd American

Society

for

Quality

(ASQ),

2004;

“Survey”

[online]

ASQ

http://asq.org/learn-about-quality/data-collection-analysistools/overview/survey.html [Accessed 13/05/2018] American Society for Quality (ASQ), 2017; “Data Collection and Analysis Tools” [online]

American

Society

for

Quality,

USA

http://asq.org/learn-about-

quality/data-collection-analysis-tools/overview/overview.html [Accessed 10/11/2017]

Ausden, M., Dixon, M., Lock, L., Miles, R., Richardson, N. & Scott, C., 2018; “Precipitating a SEA Change in the Beneficial Use of Dredged Sediment” (Technical Report). Royal Society for the Protection of Birds Baksa, P., Cepak, F., Kovacjc, R. & Ducman, V., 2018; “An Evaluation of Marine Sediments in Terms of Their Usability in the Brick Industry: Case Study Port of Koper” J. sustain. dev. energy water environ. syst., 6(1), pp 78-88, 2018, DOI: https://doi.org/10.13044/j.sdewes.d5.0183 Beeghly, J.H. & Schrock, M., 2009; “Dredge Material Stabilization Using the Pozzolanic or Sulfo-Pozzolanic Reaction of Lime By-Products to Make an Engineered Structural Fill” World of Coal Ash Page 188



Boes, 2015; “BRAIN-be project on earthquakes and tsunamis along the Nankai subduction

zone,

Japan”

[online]

Nankai

subduction

zone,

Japan

http://quakerecnankai.blogspot.co.uk/2015/10/if-i-had-hammer.html [Accessed 01/03/2018] Bolam, S.G., & Whomersley, P., 2005; “Development of macrofaunal communities on dredged material used for mudflat enhancement: a comparison of three beneficial use schemes after one year.” Marine Pollution Bulletin 50 Bortone, G., Arevalo, E., Deibel, I., Detzner, H.D., de Propris. L., Elskens, F., Girodano, A., Hakstege, P., Hamer, K., Harmsen, J., Hauge, A., Palumbo, L. & van Veen, J., 2004; “Sediment and Dredged Material Treatment” Verlagsgruppe Huthig Jehle Rehm GmbH BoskalisCSD,

2018;

Netherlands

“Cutter

Suction

Dredgers”

[online]

Royal

Boskalis,

https://boskalis.com/about-us/fleet-and-

equipment/dredgers/cutter-suction-dredgers.html [Accessed 25/02/2018] Bray, R. N., Bates, A. D. & Land, J. M., 1997; “Dredging: A Handbook for Engineers (2nd Edition)” Arnold Bray, R. N., 2008; “Environmental Aspects of Dredging” Taylor and Francis Brils, J., de Boer, P., Mulder, J. & de Boer, E., 2014; “Reuse of dredged material as a way to tackle societal challenges” Springer Verlag Berlin Heidelberg "The final publication is available at link.springer.com” Burt, T. N., 1996; “Guidelines for the beneficial use of dredged material” HR Walingford Central Dredging Association (CEDA), 2009; “Dredging and the environment: Moving sediments in natural systems” Central Dredging Association Central Dredging Association (CEDA), 2010; “Dredged Material as A Resource: Options and Constraints” Central Dredging Association CEDA, 2013; “Dredging Services and Dredging and Marine Construction” CEDA

Page 189



CEFAS, 2002; “Guidelines for the conduct of benthic studies at aggregate dredging sites”, Centre for Environment, Fisheries and Aquaculture Science on behalf of the Department for Transport, Local Government and the Regions Chattopadhyay, S. & Chattopadhyay, D., 2015; “Remediation of DDT and Its Metabolites in Contaminated Sediment” Current Pollution Report Chen, C.S. & Tan, S.M., 2002; “A case history of a coastal land reclamation project”, GSM-IEM Forum on Engineering geology and Geotechnics in Coastal Development, Sepakat Setia Perunding (SSP) Consulting Engineers, Malaysia Choi, Y., Wu, Y., Sani, B., Luthy, R.G., Werner, D. & Kim, E., 2016; “Performance of retrievable activated carbons to treat sediment contaminated with polycyclic aromatic hydrocarbons” Journal of Hazardous Materials Volume 320, 15 December 2016, Pages 359-367 Collins

Dictionary,

2018;

[online]

Collins

https://www.collinsdictionary.com/dictionary/english/dredging

Dictionary,

UK

[Accessed

11/02/2018] Collins, K. M. T., Onwuegbuzie, A. J., & Sutton, I. L., 2006; “A model incorporating the rationale and purpose for conducting mixed methods research in special education and beyond.” Learning Disabilities: A Contemporary Journal, 4, 67-100 Costaras, Michael P., Bray, RN, Lewis, Richard P. and Lee, Mark W.E., 2011; “The Importance of Bed Material Characterisation in Planning Dredging Projects” Terra et Aqua – Number 123 Coughlan, M., Cornin, P. & Ryan, F., 2007; “Step ‘by-step guide to critiquing research. Part 1: quantitative research” British Journal of Nursing. 2007. Vol 16, No II Creswell, J., 1994; “Research Design; Qualitative and Quantitative Approach” Sage Creswell, W.J., 2009; “Research Design: qualitative, quantitative and mixed methods approaches” United Kingdom: Sage Publications

Page 190



Creswell, W.J., 2014; “Research Design: qualitative, quantitative and mixed methods approaches” – 4th Edition - United Kingdom: Sage Publications DAMEN, 2017; “Water Injection Dredger 500” [online] DAMEN, Netherlands https://products.damen.com/en/ranges/water-injection-dredgers/wid500 [Accessed 13/03/2018] DAMEN, 2018; “DOP Submersible Dredge Pumps” [online] DAMEN, Netherlands http://dopdredgepumps.com/a-continuous-cycle-of-barges-is-emptied-usingthe-pontoon-based-hydraulic-offloader/ [Accessed 01/03/2018] Davies, M. & Hughes, N., 2014; “Doing a successful research project: using qualitative or quantitative methods” – 2nd Edition - Palgrave Macmillan DeFranzo, S.E., 2011; “What’s the difference between qualitative and quantitative research?” [online] SnapSurveys https://www.snapsurveys.com/blog/qualitativevs-quantitative-research/ [Accessed 16/05/2018] Department of Agriculture, Environment and Rural Affairs (DAERA), 2016; “Northern Ireland Guidance on Marine Licencing – Dredging Disposal and Aggregate Dredging, Under Part 4 of the Marine and Coastal Access Act 2009” Department of Agriculture, Environment and Rural Affairs Denzin, N., & Lincoln. Y., 1994; “Handbook of Qualitative Research.” Thousand Oaks, CA, US: Sage Publications Inc. DredgDikes, 2018; “What are Dredged Materials” [online] DredgDikes, Germany http://www.dredgdikes.eu/en/what-are-dredged-materials-751

[Accessed

11/02/2018] DredgingToday, 2018; “Huelva to Evaluate the Benefits of Dredging” [online] Dredging

Today,

Netherlands

http://www.dredgingtoday.com/2017/05/30/huelva-to-evaluate-the-benefits-ofdredging/ [Accessed 05/11/2017] DredgeYard, 2018; “PLAIN SUCTION DREDGER ECO350” [online] Dredge Yard, Russia

http://www.dredgeyard.ru/proektyi/plain-suction-dredger-eco350/

[Accessed 24/02/2018]

Page 191


DSC,

2018;

“What

is


Dredging”

[online]

DSC,

USA

http://www.dscdredge.com/what-dredge [Accessed 24/02/2018] East Marine, 2014; “East Marine launches new Grab Dredger ‘Bestla’” [online] EastMarine, USA https://worldmaritimenews.com/archives/122604/east-marinelaunches-new-grab-dredger-bestla/ [Accessed 01/03/2018] Eddy Pump, 2017; “Hydraulic Barge Offload Using 8-inch EDDY Pump Dredger” [online]

Eddy

Pump

Corporation,

California

USA

https://www.youtube.com/watch?v=odVE3icTYj0 [Accessed 01/03/2018] Eftec, 2015; “The Economic Case for Investment in Natural Capital in England: LAND USE APPENDIX.” Report for the Natural Capital Committee Elliott, M. & Hemingway, K.L., 2002; “Fishes in Estuaries” Blackwells Publications Oxford, Pages 636 EUDA, 2018; “About Dredging - Definitions” [online] European Dredging Association, Belgium https://www.european-dredging.eu/Definitions [Accessed 11/02/2018] EUDA1, 2018; “About Dredging - Types of Dredgers” [online] European Dredging Association,

Belgium

https://www.european-dredging.eu/Types_of_dredger

[Accessed 24/02/2018] EuroSoilStab, 2002; “Development of design and construction methods to stabilize soft organic soils: design guide for soft soil stabilization” CT97-0351, European Commission, Industrial and Materials Technologies Programme (Rite-EuRam III) Bryssel Everflowing, 2018; “Cutter suction dredge head for cutter suction dredger” [online] Everflowing, China http://sanddredge.com/product_detail.php?id=110 [Accessed 24/02/2018] Fellows, R. & Liu, A., 2015; “Research Methods for Construction” Wiley Blackwell FHWA, 2013; “Federal Highway Administration Design Manual: Deep Mixing for Embankment and Foundation Support” US Department of Transport [online]

Page 192



https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge /13046/011.cfm [Accessed 17/02/2018] FMI, 2017; “APEJ Region Set to Dominate the Global Dredging Market and Register a CAGR of 3% During the Assessment Period” [online] Future Market Insights, USA

https://www.futuremarketinsights.com/press-release/dredging-market

[Accessed 29/07/2018] (FMI, 2017). Groothuizen, A.G.M., 2008; “World Development and the Importance of Dredging” PIANC Harrington, Dr. J. & Smith, G., 2013, “Guidance on the Beneficial Use of Dredged Material in Ireland” Cork Institute of Technology (Pages 1 – 3) Heron Construction, 2015; “Specialist Machine Hire” [online] Heron Construction Company Limited, New Zealand https://www.heronconstruction.co.nz/Specialised+Machine+Hire.html [Accessed 07/04/2018] Hoffman, E., Barton, C., Fox, D. & Hicks, J., 2015; “Debris Screening Requirements” SMARM Hopkins, E. & White, M., 1998: “Dredging, extraction and spoil disposal activities: departmental procedures for provision of fisheries comments, Queensland Department of Primary Industries, Fish Habitat Management Operational Policy Howard, Dr. A. & Gkenakou, E., 2017; “Remediation of tributyltin-contaminated sediments and water” University of Southampton Howard, I.L., 2012; “Guidance for Using Cementitiously Stabilized Emergency Construction Materials” SERRI Report 70015-008 IMO (IMO), 2005, “Waste Assessment Guidelines Training Set Extension for the Application of Low-Technology Techniques for Assessing Dredged Material”, International Maritime Organisation, London, UK IADC, 2008; “Environmental Impact Assessments” An Information Update from the IADC IADC, 2010; “Environmental Monitoring” An Information Update from the IADC Page 193



IADC, 2014; “Facts About Environmental Equipment” An Information Update from the IADC IADC,

2018;

“The

Importance

of

Dredging”

[online] IADC,

Netherlands

https://www2.iadc-dredging.com/subject/what-is-dredging/the-importance-ofdredging [Accessed 11/02/2018] ICPR,

2013;

“The

Rhine

and

its

catchment:

an

overview—ecological

improvement—chemical water quality—survey of the action plan on floods.” Iibncsu, 2009; “Literature Reviews: An Overview for Graduate Students” [online] Iibncsu

https://www.youtube.com/watch?v=t2d7y_r65HU&feature=youtu.be

[Accessed 13/05/2018] IndiaMart,

2018;

“Van

Veen

Grab

Sampler”

[online]

https://www.indiamart.com/proddetail/van-veen-grab-sampler10809513133.html [Accessed 02/03/2018] International Association of Dredging Companies (IADC), 2005; “Dredging: The Facts” International Association of Dredging Companies International Association of Dredging Companies (IADC), 2009; “Dredged Material as A Resource” International Association of Dredging Companies International Association of Dredging Companies (IADC-BHD), 2014; “Facts About –Backhoe Dredgers” International Association of Dredging Companies International Association of Dredging Companies (IADC-TSHD), 2014; “Facts About – Trailer Suction Hopper Dredgers” International Association of Dredging Companies International Association of Dredging Companies (IADC-SI), 2015; “Facts About – Site Investigation” International Association of Dredging Companies International Commission for the Protection of the Rhine (ICPR), Koblenz, Germany. ISBN: 978-3-941994-46-1 Jan De Nul, 2014; “Dredging: Working Principles Cutter Suction Dredgers” [online] IADC, Netherlands https://www.youtube.com/watch?v=yzgXaQW8v28 [Accessed 25/02/2018] Page 194



Jan De Nul Group (JDN), 2018; “Trailer Suction Hopper Dredger” [online] Jan De Nul

Group,

Belgium

http://www.jandenul.com/en/equipment/fleet/trailing-

suction-hopper-dredger [Accessed 25/02/2018] Johnson, K.D., 2005; “Geotechnical investigations for dredging projects” Western Dredging Association (WEDA) Johnson, R. B. & Onwuegbuzie, A. J., 2013; “Mixed Methods Research: A Research Paradigm Whose Time Has Come” Educational Researcher, Vol. 33, No. 7, pp. 1426 Jones, K.W., Stern, E.A., Donato, K.R., and Clesceri, N.L., 1999; “Sediment Decontamination Treatment Train: Commercial-Scale Demonstration for the Port of New York/New Jersey” Proceedings of the 19th Western Dredging Association (WEDA XIX) Annual Meeting and Conference and 31st Texas A&M University Dredging Seminar (TAMU 31), Louisville, Kentucky Journeyman Pictures, 2016; “The Environmental Cost of Dredging in Queensland” [online]

Journeyman

Pictures,

Queensland

Australia

https://www.youtube.com/watch?v=KkiZe0aHnMM [Accessed 05/11/2017] Karacoban, H.P. & Onal, O., 2017; “Stabilization of Dredged Material of Izmir Bay Soils Using Cement and Lime Mixtures” International Journal of Advances in Mechanical and Civil Engineering, ISSN: 2394-2827 Volume-4, Issue-5, Oct.-2017 Kleverlaan, E., 2015; “Dumping of Waste and Other Matter in the Sea” Head, Office for the London Convention/Protocol and Ocean Affairs International Maritime Organization Knapton, S., 2014; “Banned pesticide DDT may raise risk of Alzheimer's disease” [online] The Telegraph, UK https://www.telegraph.co.uk/news/science/sciencenews/10600234/Banned-pesticide-DDT-may-raise-risk-of-Alzheimersdisease.html [Accessed 03/07/2018] Kolman, R., 2013; “New Land by the Sea: Economically and Socially, Land Reclamation Pays” International Association of Dredging Companies

Page 195



Kolman, R. & Van t’ Hoff, J., 2013; “Port Expansion Through Land Reclamation” Port Planning, Design and Construction – IADC Khairie, M., 2012; “Topic 5 Sampling” [online] University Utara Malaysia https://www.youtube.com/watch?v=Q_-Bts76TfI [Accessed 20/05/2018] Kinlan, D. & Roukema, D.C., 2010; “Adverse Physical Conditions and the Experienced Contractor Test” Terra et Aqua 119 Krause, P. A. & McDonnell, K. A., 2000; “Beneficial Reuse of Dredged Material for Upland Disposal” Harding Lawson Associates Lakshman, M., Sinha, L., Biswas, M., Charles, M. & Arora, N.K., 2000; “Quantitative Vs Qualitative Research Methods” Indian Journal of Paediatrics – Springer India Lahtinen, P., Forsman, J., Kiukkonen, P., Kreft-Burman, K. & Niutanen, V., 2014; “Mass Stabilisation as A Method of Treatment of Contaminated Sediments” Universität Rostock Lapan, S.D., Quartaroli, M.T. & Riemer, F.J., 2012; “Qualitative Research - An Introduction into Methods and Design” - Jossey-Bass Limeira, J., Etxeberria, M., Agulló, L., Molina, D., 2011; “Mechanical and durability properties of concrete made with dredged marine sand” Department of Construction Engineering, Polytechnic University of Catalonia, Jordi Girona, 1-3, C1 Barcelona 08034, Spain Lui,

2015;

[online]

Dawson

Books,

UK

https://www.dawsonera.com/readonline/9781118915721 [Accessed 10/11/2017] (Lui, 2015). Made In China, 2018; “Qingzhou Zhicheng Machinery Equipment Co., Ltd” [online] China

https://nl.made-in-china.com/co_zcdredger/image_Chain-Bucket-

Dredger-for-Mining-Gold_hogiyhghy_GSPtOhlFHQgv.html [Accessed 26/02/2018]

Page 196



Maher, A., Douglas, W.S., Jafari, F. & Pecchioli, J., 2013; “The Processing and Beneficial Use of Fine-Grained Dredged Material – A Manual for Engineers”, Rutgers Center for Advanced Infrastructure and Transportation Maher, A., Kitazume, M., Janbaz, M., Miskewitz, R., Douglas, S., & Yang, D., 2018; “Utilisation of Pneumatic Flow Tube Mixing Technique (PFTM) for Procesing and Stabilisation of Contaminated Soft Sediments in the NY/NJ Harbor” Marine Georesources & Geotechnology Makusa, G.P., 2015; “Stabilization-Solidification of High Water Content Dredged Sediments: Strength, Compressibility and Durability Evaluations” Lulea University of Technology Manap. N. & Voulvoulis, N., 2014; “Environmental Management for Dredging Sediments – The Requirement for Developing Nations” Elsevier Massarch, K.R. & Topolnicki, M., 2005; “Regional report: European practise of soil mixing technology” Proceeding of the international conference on deep mixingbest practice and recent advances. Stockholm McLeod, S., 2008; “Qualitative vs. Quantitative Research” [online] Simply Psychology

https://www.simplypsychology.org/qualitative-quantitative.html

[Accessed 12/05/2018] MeanThat,

2016;

“Selecting

Samples

for

A

Research”

Swedenhttps://www.youtube.com/watch?v=C9Lv7ZIOaXk

[online] [Accessed

20/05/2018] MEMG, 2003; “Group Co-ordinating Sea Disposal Monitoring - Final Report of the Dredging and Dredged Material Disposal Monitoring Task Team” Lowestoft Mezencevova, A., Yeboah, N. N., Burns, E. S., Kahn, L. K. and Kurtisk, E., 2012; “Utilization of Savannah Harbor River Sediment as the Primary Raw Material in Production of Fired Brick” Journal of Environmental Management, Vol. 113, pp 128-136, 2012, https://doi.org/10.1016/j.jenvman.2012.08.030

Page 197



Miano, A. E., 2016; “Beneficial Use of Dredged Materials” Proceedings of the Western Dredging Association and Texas A&M University Center or Dredging Studies – Dredging Summit and Expo 2015 Millrath, K., Kozlova, S., Shimanovich, S. & Meyer, C., 2001; “Beneficial Reuse of Dredged Material” Columbia University in City of New York Millward, R.N., Bridges, T.S., Ghosh, U., Zimmerman, J.R. & Luthy, R.G, 2005; “Addition of activated carbon to sediments to reduce PCB bioaccumulation by a polychaete

(Neanthes

arenaceodentata)

and

an

amphipod

(Leptocheirus

plumulosus)” Environ Sci Technol. 2005;39:2880–2887 Minichiello, V., 1990; “In-Depth Interviewing: Researching People” Longman Cheshire Morijn, R., 2011; “Nieuwe snijkop voor een cutterzuiger - New cutter head of a dredger”

[online]

Flickr,

https://www.flickr.com/photos/10989519@N06/5925546554

Netherlands [Accessed

24/02/2018] Mostafa, Y.E.S., 2011; “Environmental impacts of dredging and land reclamation at Abu Qir Bay, Egypt” Elsevier Murden, W. R., 1995; “An update on submerged berms in coastal zone utilizing dredged material” Proc. 14th World Dredging Congress, Amsterdam 1995 Murray, L.A., 2008; “Dredged Material as a Resource” Terra et Aqua 112 Naoum, S.G., 2013; “Dissertation Research and Writing for Construction Students” 3rd Edition – Routledge Taylor & Francis Group National Ocean and Atmospheric Administration (NOAA), 2017; “What is Dredging?” [online] National Ocean and Atmospheric Administration U.S. Department

of

Commerce,

USA

https://oceanservice.noaa.gov/facts/dredging.html [Accessed 11/02/2018] Offshore Site Investigation and Geotechnics Committee (OSIG), 2004; “Guidance Notes on Geotechnical Investigations for Marine Pipelines” The Society for Underwater Technology Offshore Site Investigation and Geotechnics Committee Page 198



Oida, T., 2007; “Continuous Dewatering System for Dredged Sediment with High Water Content” Penta-Ocean Construction Co. Ltd., Tokyo, Japan Oota, M., Mitarai, Y. & Iba, H., 2009; “Outline of Pneumatic Flow Mixing Method and Application for Artificial Island Reclamation Work,” Proceedings of the Deep Mixing 2009 Okinawa Symposium and International Symposium on Deep Mixing & Admixture Stabilization, May 19-21, Okinawa, Japan O’Shea. Dr. M., 2017; “Recent approaches to the Solidification and Stabilisation (S/S) of Contaminated Dredge Material in Ireland” Dr. Michael O’Shea, Malachy Walsh and Partners, Tralee, County Kerry, Ireland OSPAR Commission, 2004; “Environmental Impacts to Marine Species and Habitats of Dredging for Navigational Purposes” OSPAR Commission OSPAR Commission, 2009; “Assessment of The Environmental Impacts of Dredging for Navigational Purposes” OSPAR Commission OSPAR Commission, 2009; “JAMP Assessment of The Environmental Impacts of Dumping of Waste at Sea” OSPAR Commission OSPAR Commission, 2010, “Assessment of the environmental impact of dredging for navigational purposes” OSPAR Commission OSPAR Commission, 2014; “OSPAR Guidelines for the Management of Dredged Material at Sea” OSPAR Commission OSPAR Work Area, 2017; “Dredging & Dumping” [online] OSPAR, Netherlands https://www.ospar.org/work-areas/eiha/dredging-dumping

[Accessed

19/01/2018] OxfordDictionaries, 2018; “Oxford Dictionary” [online] Oxford University Press https://en.oxforddictionaries.com/definition/sediment [Accessed 11/02/2018] Parson, L.E., & Swafford, R., 2012; “Beneficial Use of Sediments from Dredging Activities in the Gulf of Mexico.” Journal of Coastal Research 60 Payne, R.B., Fagervold, S.k., May, H.D. & Sowers, K.R., 2013; “Remediation of polychlorinated biphenyl impacted sediment by concurrent bioaugmentation with

Page 199



anaerobic halorespiring and aerobic degrading bacteria” Environ Sci Technol. 2013 Apr 16; 47(8): 3807–3815 Pennsylvania Department of Environmental Protection, 2001; “The use of dredged material in abandoned mine reclamation”, Bureau of Land Recycling and Waste Management Pennsylvania, Department of Environmental Protection, Bureau of Abandoned Mine Reclamation PIANC, 1992; “Beneficial uses of dredged material, a practical guide”. Report of PIANC Working Group 19 PIANC, 2009; “Dredged Material as A Resource; Options and Constraints” PIANC Port of London Authority (PLA), 2018; “Maintenance Dredging” [online] Port of London

Authority,

UK

https://pla.co.uk/Environment/Maintenance-Dredging

[Accessed 11/02/2018] Powers. J., 2017; “Tipping Point LLC Will Facilitate Beneficial Use in Connecticut Area”

[online]

International

Dredging

Review,

USA

http://www.dredgemag.com/September-October-2017/Tipping-Point-LLC-WillFacilitate-Beneficial-Use-in-Connecticut-Area/ [Accessed 07/04/2018] PREMIAM, 2011; “Pollution response in emergencies marine impact assessment and

monitoring

-

post-incident

monitoring

guidelines”,

The

Centre

for

Environment, Fisheries and Aquaculture Science; Cefas Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk UK Priestly, S.J., 1995; “Beneficial Use of Mudcrete in Land Reclamation” Transactions on the Built Environment vol 8 – WIT Press Priestly, S.J., 1995; “Beneficial Use of Mudcrete In Reclamation” [online] WIT Press

https://www.witpress.com/elibrary/wit-transactions-on-the-built-

environment/9/10241 [Accessed 05/11/2017] Pullar, A. & Hughes, S., 2009; “Project Next Generation – Dredging Methodology and Disposal Alternatives” Port of Otago Ltd Punch, K., 1998; Introduction to Social Research; Quantitative and Qualificative Approaches” London: Sage Page 200



Rauner, B., 2009; “Environmental Health Fact Sheet - Polychlorinated Biphenyls (PCBs)”

[online]

Illinois

Department

of

Public

Health

http://www.idph.state.il.us/envhealth/factsheets/polychlorinatedbiphenyls.htm [Accessed 03/07/2018] Rijkswaterstaat, 2013; “Eco-Engineering in the Netherlands – Soft Interventions with a Solid Impact” Rijkswaterstaat Ministry of Infrastructure and the Environment RoyalIHC,

2018;

“Booster

stations”

[online]

IHC,

Netherlands

https://www.royalihc.com/en/products/dredging/cutter-dredging/boosterstations [Accessed 24/02/2018] RoyalIHC-TSHD, 2018; “Custom-built trailing suction IHC,

Netherlands

hopper dredgers” [online]

https://www.royalihc.com/en/products/dredging/hopper-

dredging/custom-built-trailing-suction-hopper-dredgers Samarasnghe, 2015; “De-silting Through Dredging” [online] The Sunday Leader http://www.thesundayleader.lk/2015/06/21/de-silting-through-dredging/ [Accessed 29/07/2018] Schaeferr, C., 2016; “Get Lit: The Literature Review” [online] Texas A & M University, USA https://www.youtube.com/watch?v=9la5ytz9MmM [Accessed 13/05/2018] SedNet, 2002; “Treatment and Confined Disposal of Dredged Material” DutchGerman Exchange on Dredged Material – Part 2 Shabankareh, O., Ketabdari, M.J. & Shabankareh, M.A, 2017; “Environmental Impact of Geotubes and Geotextiles used in Breakwaters and Small Breakwaters Construction (Case Study: Rigoo Public Breakwater in South of Qeshm island Iran)” INTERNATIONAL JOURNAL OFCOASTAL & OFFSHORE ENGINEERING Sharma, H. D. & Reddy, K. R., 2004; "Geoenviromental Engineering: Site Remediation,

Waste

Containment,

and

Emerging

Waste

Management

Technologies" Wiley, New York

Page 201



Sheehan, C., Harrington, JR., Murphy, JP. & Riordan JD., 2008; “An investigation into potential beneficial uses of dredge material in Ireland”, In: WEDA XXVIII and Texas TAMU 39th dredging seminar Sheehan, C. & Harrington, J., 2012; “Management of Dredge Material in Ireland – A Review”, Waste Management, Volume 32, Issue 5 Sheenan, C., Harrington, J. & Murphy, J.D., 2009. “Dredging and Dredge Material Beneficial Use in Ireland” - International Association of Dredging Companies Shuttleworth, 2008; “Case Study Research Design [online] Experiment Resources http://www.experimentresources.com/case-study-research-design.html [Accessed 12/05/2018] Siham, K., Fabrice, B., Vincent, D. & Nor Edine, A., 2005; “Beneficial Use of Marine Dredged Sand and Sediments in Road Construction” Civil Engineering Department of Ecole des Mines de Douai STABLE, 2009; “Controlled Treatment of TBT-Contaminated Dredged Sediments for the Beneficial Use in Infrastructure Applications - Case: Aurajoki – Turku – LIFE06 ENV/FIN/000195” Life Environmental StartDredging, 2018; “How to start a successful dredging project” [online] IHC Netherlands http://www.startdredging.com/how-to-start-a-successful-dredgingproject/ [Accessed 24/02/2018] State

of

the

Environment,

2016;

[online]

Commonwealth

of

Australia

https://soe.environment.gov.au/theme/marineenvironment/topic/2016/dumped-wastes [Accessed 19/01/2018] Stern, E.A., Miskewitz, R., Maher, A., Kovalik, A., Kitazume, M., Yang, D., & DeWan, R.M., 2018; “Pneumatic Flow Tube Mixing for Beneficial Use of Impacted Sediments” Tipping Point Resources Group, LLC Tashakkori, A., & Teddlie, C., 1998; “Mixed methodology: Combining qualitative and quantitative approaches” Applied Social Research Methods Series, Vol. 46 Thousand Oaks, CA: Sage.

Page 202



Taylor, D., 2010; “Writing the Literature Review (Part One): Step-by-Step Tutorial for

Graduate

Students”

[online]

Taylor

USA

https://www.youtube.com/watch?v=2IUZWZX4OGI&feature=youtu.be [Accessed 13/05/2018] Taylor, H., 2014; “Dredging Up the Past: The Danger of Remobilizing Heavy Metals” University of Denver Water Law Review ToxTown, 2017; “Polycyclic Aromatic Hydrocarbons (PAHs)” [online] U.S. National Library

of

Medicinal,

USA

https://toxtown.nlm.nih.gov/text_version/chemicals.php?id=80

[Accessed

05/11/2017] Uelman, F., 2015; “Dredging: Webinar - Dredging Equipment” [online] IADC, Netherland

https://www.youtube.com/watch?v=U4UZYrj3Xzc

[Accessed

27/02/2018] UK

Marinesac,

2018;

“Dredging

and

Disposal”

[online]

UK

http://www.ukmarinesac.org.uk/activities/ports/ph5.htm [Accessed 11/02/2018] UK Marine (UKM), 2017; “Environmental Impacts of Maintenance Dredging and Disposal”

[online],

UK

Marine

Sac’s

http://www.ukmarinesac.org.uk/activities/ports/ph5_2.htm

Project,

UK

[Accessed

05/11/2017] UK National Ecosystem Assessment (UKNEA), 2011; “The UK National Ecosystem Assessment Technical Report.” UNEP-WCMC, Cambridge United States Environmental Protection Agency, 1993; “Solidification/stabilization and its application to wastes material.” Technical resource document: EPA/530/R93/012 U.S Army Corps of Engineers (USACE), 1983; “Engineering and Design: Dredging and Dredged Material Disposal” EM 1110-2—5025 U.S Army Corps of Engineers U.S Army Corps of Engineers (USACE), 2015; “Dredging and Dredged Material Management” EM 1110-2—5025 U.S Army Corps of Engineers

Page 203


USEPA,

2017;

Environmental

“Learning

About

Protection

Ocean

Agency,


Dumping” USA

[online]

United

States

https://www.epa.gov/ocean-

dumping/learn-about-ocean-dumping [Accessed 19/01/2018] USGC, 2018; “U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 00-358” [online] USGC,

USA

https://pubs.usgs.gov/of/2000/of00-358/text/chapter1.htm

[Accessed 02/03/2018] Van Mieghem, J., Smits, J. & Sas, M., 1997; “Large Scale Dewatering of FineGrained Dredged Material” Terra Aqua – Number 68 Van den Eynde, D., Lauwaert, B., Martens, C., Pirlet, H., 2013. “Compendium for Coast and Sea: Integrating knowledge on the socio-economic, environmental and institutional aspects of the Coast and Sea in Flanders and Belgium” – Flanders Marine Institue (VLIZ), Pages 97 – 104 & 113-120 Van der Wal, D., Forster, R.M., Rossi, F., Hummel, H., Ysebaert, T., Roose, F. & Herman, P.M.J., 2010; “Ecological evaluation of an experimental beneficial use scheme for dredged sediment disposal in shallow tidal waters” Marine Pollution Bulletin, Vol. 62, No. 1, 2011, p. 99-108 Van der Werf, J., Reinders, J., Van Rooijen, A., Holzhauer, H. & Ysebaert, T., 2015; “Evaluation of a tidal flat sediment nourishment as estuarine management measure.” Ocean & Coastal Management 114 Van den Eynde, D., Lauwaert, B., Martens, C., Pirlet, H., 2015; “Dredging and dumping” In: Pirlet, H., Verleye, T., Lescrauwaet, A.K., Mees, J. (Eds.), Compendium for Coast and Sea 2015: An integrated knowledge document about the socio-economic, environmental and institutional aspects of the coast and sea in Flanders and Belgium. Ostend, Belgium, p. 97-104 Van Oord, 2014; “Water Injection Dredging - How does it work (EN)” [online] Van Oord, Netherlands https://vimeo.com/69300630 [Accessed 13/03/2018] Van t’ Hoff, J. & Van der Kolff, A.N., 2012; “Hydraulic Fill Manual: For Dredging Reclamation Works” CRC Press

Page 204



Virtuel, 2018; “Boremetode: gravity coring og box coring” [online] Denmark http://virtuelgalathea3.dk/artikel/boremetode-gravity-coring-og-box-coring [Accessed 02/03/2018] Vivian, C., Birchenough, A., Burt, N., Bolam, S., Foden, D., Edwards, R., Warr, K., Bastreri, D. & Howe, L., 2010; “ME1101 - Development of Approaches, Tools and Guidelines for the Assessment of the Environmental Impact of Navigational Dredging in Estuaries and Coastal Waters” Cefas Vlasblom, W.J., 2003; “Introduction to Dredging Equipment” Delft University of Technology, Pages 1 – 27 Welch, M., Mogren, E. T. & Beeney, L., 2016; “A Literature Review of the Beneficial Use of Dredged Material and Sediment Management Plans and Strategies” Portland State University. Hatfield School of Government. Centre for Public Service Wilk, C., 2015; “Innovations in Stabilization Treatment of Dredged Materials at Placement Areas” Proceedings of Western Dredging Association and Texas A&M University Center for Dredging Studies - Dredging Summit and Expo 2015 World Trout Trust, 2013; “Unintended effects of dredging” [online] World Trout Trust,

UK

https://www.youtube.com/watch?v=OAZ_BuyM41s

[Accessed

05/11/2017] Xu, Y., Changhong, Y., Baotian, X., Xiaohong, R. and Zhi, W., 2013; “The use of Urban River Sediments as a Primary Raw Material in the Production of highly Insulating Brick” Ceramics International, Vol. 40, No. 6, pp 8833-8840, 2013, https://doi.org/10.1016/j.ceramint.2014.01.105 Yu. H., 2014; “Beneficial Use of Dredged Materials in Great Lakes Commercial Ports for Transportation Projects” University of Wisconsin-Madison Yu, H., Yin, J., Soleimanbeigi, A., Likos, W.J., & Edil, T.B., 2016; “Engineering Properties of Dredged Material Stabilized with Fly Ash” Zohrabi, M., 2013; “Mixed Method Research: Instruments, Validity, Reliability and Reporting Findings” University of Tabriz, Iran - Theory and Practice in Language Studies, Vol. 3, No. 2, pp. 254-262

Page 205



Powers. J., 2017; “Tipping Point LLC Will Facilitate Beneficial Use in Connecticut Area” [online] International Dredging Review, USA

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APPENDIX A

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APPENDIX B

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APPENDIX C

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QUESTION 1 In the past 5 years, has your organisation been involved in any dredging operations? If so, could you please provide a brief description of your latest dredging projects? Respondent

Answer

1

7

Yes. Maintenance dredging building of nature areas (e.g. bird islands) Fairway deepening, coastal protection (beach and offshore replenishments) Over that time, I worked on roughly 12 dredging projects (design to construction) from environmental restoration to strictly navigation. Yes. The organisation has been involved in a number of dredging projects, ranging from maintenance and capital dredging of ports, harbours, channels and fairways. ******* 2 Pipeline, ******** LNG project Maintenance dredging, ****** LNG Project Rock installation, **** ****** Phase 2 port expansion & ******** Maintenance Dredging Canal and river trust dredging, EA framework dredging, Private client dredging. Environmental dredge campaign in ********, with the dredge and treatment of polluted in-Harbour material for disposal on land. Land reclamation

8

****** harbour, rock dredge and capital dredge

9

We are an in-house dredging company for all the ports in ******. We are a parastatal. We complete all the maintenance dredging in our ports system Capital dredging works in ******** - ********, ********, ********, ******** and ********. All these projects were undertaken with a backhoe dredge, hopper barges and tugs with the material being dumped offshore. Maintenance, Capital and Remediation Dredging in ******** - ********, Port ********, Port ********, ******** Islands, ********, Port ********, ******** ********. These projects were also undertaken with a backhoe dredge, hopper barges and tugs, for the ******** and ******** projects the material was stabilised with cement and used as engineered fill to form a reclamation From 2004 until 2015, I was the Project Manager of the ******** & ******** Harbour Deepening project, which brought several channels down to 50 ft, over 38 million m³ of material was dredged. Yes, maintenance dredging / investments

2 3 4 5 6

10

11

12 13

We have been involved with assisting USACE in sampling and characterizing dredged material for ocean disposal. I really like Page 220



the idea of using dredged material in more creative ways than just putting in a landfill or on the bottom of the ocean. 14 15

16

Dredging for redevelopment of a dry bulk terminal at the Port of ******** Yes, we do the maintenance of the ******** Coast (Beach nourishment), maintenance of Channels and Rivers (dredging) and capital dredging. ******** Terminal Phase 1 Reclamation, Wharf Construction and Dredging – Package 1. Under this project, capital dredging is carried out to deepen the ******** Fairway and basins to minus 23m at chart datum as well as construction of sandkey

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QUESTION 2 During dredging operations, what volume of dredged material was extracted? Could you please provide a brief description of the characteristics of this material? Respondent

Answer

1

Between 10 and 20 million m³.

2

Estimate a removal of 948,034 m³ of dredged material. Mostly sand with a 20 to 30% involving nutrient rich organic sediments (mcuk). 1.2 million m³ from the Port of ********. Mainly consisting of marine mud. Mostly sand, some clay and organic material. Latter used in reclamation area sand and silt, some rock/cemented material but was already dredged sandy seabed, installing hard rock removing caprock and some bedrock with sand on top. This can be anything from 0 to several tens of thousands m³.

3 4

5 6 7 8 9

120000 m³ fine silts with contaminants, primarily fine material with a layer of gravel in the dredge area. Over 500,000 m³ was extracted. Material characteristics is medium grained. 40,000 m³ rock and 25,000 m³ silt

12

We dredge around 4.7 million m³. The material varies from sand, silt, mud, clay and rocks. 3.4 million m³of material in ******** with about 1% of that being rock type material, the balance being marine sediments, sands and stiff clays. 350K cubic metres of material in ******** with about 10% of that being rock type material, the balance being marine sediments, sands and stiff clays. Over 38 million m³ of material was dredged. Material consisted of hard schist that had to be blasted before removal, sand, glacial till, clay, and mud. Based on chemical analysis, some martial, mostly the mud, could not be placed in the open water Mainly sand. Often silt during maintenance dredging.

13

We were not involved with every characterization.

14

4587 m³; unsuitable for beach replenishment due to grain size considerations and moderate contamination but reused as fill for port development. Yearly amount of sediments being dredged is about 10 - 20 million m³ Approximately 50 million m³. Mainly soft clayey material

10

11

15 16

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QUESTION 4 What percentage of dredged material was disposed of at sea? Respondent

Answer

1

85%

2

None for those projects

3

0% All dredgings were used in a reclamation project.

4

80% 100% 0% 100%

5

In 2017 9% of the dredgings was disposed of via estuarine water injection dredgings

6

0 although the next phase of the project is for deepening the pocket and disposal at sea of rock and stiff clays.

7

Nil

8

100%

9

All the material from the ports are dumped at sea. Only sand from the sandtraps at the breakwater are reclaimed on the northern beaches

10

95%

11

About 75%, I don’t remember the exact

12

Maintenance = 100%

13

We are on the front end of this type of work and I don’t always know how much goes to ocean but I would guess most.

14

0

15

Only material that is dredged in the marine environment is beneficial used (disposed of) at sea. None. All are re-used as reclamation fill materials for this project

16

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QUESTION 5 Does your organisation consider DM as a natural resource (Contaminated or Uncontaminated), utilising DM for BU to replace other unsustainable resources? Respondent

Answer

1

In some, but not all cases

2

Always seek a beneficial use or reuse if at all possible. Cost dictates the final outcome.

3

Yes, dredged material is reused when possible.

4

Yes, material can be used for building materials and to reclaim land. Sometime organic and clayey material are not considered as reclamation material, but this is not seen by us as best practice. Often valuable sand is deposited offshore because it is the cheapest and easiest option for a particular project.

5

We attempt to re-use dredgings where possible. Often this can be limited by contaminant levels, logistics, costs.

6

Suitable reclaimed dredged material can be beneficial, particularly for the client and help develop land and minimise maintenance dredge costs.

7

Yes. All materials were reused for various construction purposes also

8

Not as much as they should. In my honest opinion.

9

We haven’t and we are not in that business. It doesn’t mean that it won’t be something we could consider though

10

No

11

Yes

12

If possible, we use the "sand part" of the dredged material as land reclamation

13

N/A

14

NA, I am a consultant, but would consider all options.

15

Yes. But we also consider sediments as a natural part of aquatic systems. So disposal back to the water system is also

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regarded as beneficial and therefore we think this management option belongs to the category "reuse". 16

Yes, alternative material to sand which is traditionally used for land reclamation. These materials have been tested to ensure that the heavy metals content is within acceptable limits.

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QUESTION 6 Are

SIs

conducted

to

determine

the

physical,

chemical

&

biological

characteristics of the sediments, to explore a suitable BU scheme? Respondent

Answer

1

Yes

2

Yes

3

Yes

4

Yes

5

Yes, always

6

On certain projects.

7

Site investigation have to be undertaken but are not always undertaken for purposes of reuse. Yes, mostly contaminant analysis, particle size, nutrient testing.

8 9 10

Yes, but these in general have some variance, it may be a result of the logging data and expired bathymetric survey data. Yes. It’s part of the planning stage.

11

SI is conducted only for a view to dispose of the material.

12

No for the maintenance dredging

13

15

yes, at a very minimum borings are used to determine what the material is. Some material is excluded from further chemical analysis, such as rock, sand and clay. Yes. This is where we come in. There are different regional requirements for testing in the US but they are all based on federal laws. Yes, Lots of regulations and protocols in place for that.

16

Yes, soil investigations were carried out during planning stage.

14

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QUESTION 8 If the SI did detect contaminates in the sediments, what contaminates were present?

Respondent

Answer

1

Several kinds, mainly PCBs, PAHs, heavy metals

2

Arsenic was the only contaminate above state standards for "normal" disposal.

3

TBT’s, PAH’s, Copper, Lead, Mercury, Zinc, Nickel etc.

4

TBT, sediment were dumped offshore first & covered with ‘clean’ material. TBT concentrations were very low, so this was allowed by the regulator.

5

Varies its fairly dependant on location but can be limiting in reuse schemes. Heavy metals and PAHs tend to be persistent & problematic.

6

TBT’s pollutants were encountered

7

Mud and fossils

8

N/A

9

N/A

10

Heavy Metals, Tbt's

11

Mostly PCBs. The ******** & ******** Harbour has about 118 contaminates that are tested for PAK, TBT (this has to go to a waste plant of course)

12 13 14

This depends on the project. There is a priority list of contaminates that are measured Heavy metals, PCBs, pesticides (DDTs)

15

A cocktail.

16

N/A

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QUESTION 14 Has your organisation recently completed any land reclamation or port expansion projects? Respondent

Answer

1

Yes

2

Yes

3

Yes

4

Yes

5

No

6

No

7

Not recently, but we are pursuing several.

8

Yes, currently expanding the reclamation at the Port of ********

9

Maintenance dredging of ********, but all material was dumped offshore Maintenance dredging of ******** again all material dumped offshore Beach nourishment in ******** material was dredged from borrow area not maintenance dredging

10

No

11

Yes. That’s our area of professionalism

12 13

No, but we did replenish beaches that were about to be nonexistent Yes

14

Not directly, but will answer below

15

Yes ******** 2 (however not very recently)

16

The ******** Terminal Phase 1 Reclamation project is ongoing and to be completed in 2021

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QUESTION 15 During land reclamation or port expansion, were S/S technologies utilised? Respondent

Answer

1

No

2

No

3

No

4

Yes

5

Yes

6

N/A

7

Yes, a pugmill system used on flattop barge for S/S & placement of the DM.

8

In ********, ******** ******** and related project vibro compacting of calcareous sand was undertaken.

9

No, however municipality sand tested before beach placement

10

Yes - Cement stabilisation

11

Yes

12

N/A

13

No (if chemical stabilization is what you refer to)

14

No, suitable sediments (sand) were dredged and used

15

Untreated DM clayey soils & excavated earth are soft & require ground improvement techniques to obtain the required engineering properties for the intended use of the reclaimed land as container port. Large ground settlement is normally expected of these untreated soft soils. In addition, the existing seabed materials where the land was reclaimed are also soft. Hence, the large-scale use of such materials as fills would require the reclaimed land to be treated to eliminate large ground settlement due to primary consolidation so that the reclaimed land could be used for construction of port facilities immediately. If the reclaimed land is left untreated, it would take 50 years for the ground to consolidate naturally. Soil

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improvement work using PVDs & sand surcharge method is being carried out

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QUESTION 16 Are EIAs conducted to identify potential issues at the dredge site & the BU placement site? Respondent

Answer

1

Yes

2

Yes

3

Yes

4

Yes

5

Yes, always.

6

Yes, always required as part of the client’s scope.

7

Regulator & governments are very conservative with reusing DM from maintenance activities, because of pollutants.

8

N/A

9

Yes

10

No

11

Yes - usually only to confirm if the material is contaminated - if it’s not contaminated then it gets dumped offshore

12

An Environmental Impact Statement was prepared for the project & it relied on the placements sites to have their own assessments.

13

Yes

14

Depends on the scale of the project and sites.

15

Yes. Prior to commencement of the reclamation works, EIAs were carried out to determine the impact of the works on the surrounding environment as well as to determine the scope of the environmental monitoring and management plan (EMMP). During the construction works, an EMMP will be put in place by appointed specialist consultant to protect the marine environment while allowing works to be carried out. In addition, corals impacted by the work were relocated to suitable sites. The public & NGOs were engaged in the corals relocation work.

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QUESTION 17 Is your organisation selecting dredging equipment based on future beneficial reuse of the dredged material? Respondent

Answer

1

No

2

No

3

No

4

Yes

5

Yes

6

N/A. Always contract out the actual dredging.

7

Depending on the economic benefits to the organisation.

8

Typically, the cheapest option is identified and chosen, sometimes the material dredged can be used in reclamation area. Volumes/time unit are too large typically to process the dredged material in any other way or it is a by-product (fraction of entire volume).

9

No, dredge equipment is selected for company operations

10

Not at the moment, but this could change

11

The actual dredging contractor selects the material, we made a best guess of that equipment to develop our cost estimates

12

Yes

13

N/A

14

Sometimes/not always. depends on the project scope.

15

N/A

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QUESTION 18 If your organisation recently carried out stabilisation/solidification of dredged material, please give a brief description of the equipment used? Respondent

Answer

1-5

N/A

6

Pugmill barge and flattop barge.

7

Solidification is probably consolidation

8

Backhoe Dredger, Spud Barge, Dump Barges, Longreach Excavators, Articulated Dumpers and Processing Plant on shore

9

Hammers, vibracores, dosers, vivrators and rollers, dewaterring and other dry plants

10

No

11

Cement stabilisation of marine sediments using a pugmill

12

we did not do the actual work. Regardless of the site the material went to, the scow was first dewatered/decanted. Then agents were added to the material while it was still in the scow or the material was removed and put into a hopper mixer.

13

vibro-compaction

14

Such things normally are done on a pilot scale. We did pilots already starting from the late 1980's.

15

PVD installation machines and sand handling equipment like excavators and ADTs are used to build up the sand surcharge during soil improvement work

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QUESTION 19 Please give a brief description of any positive and negative environmental impacts that arose during the beneficial reuse of dredged materials. Respondent

Answer

1-2

N/A

3

Not aware of any negative. Positives: Landfill cover, Wetlands/habitats enhancement or creation, Land reclamation

4

Reduced carbon footprint due to reduced tug boat movements to dispose of materials and reduced truck movements. This also resulted in less traffic congestion as it removed 160,000 truck movements from ******** CBD. There was also a reduction in sediment resuspension in the water column. the stabilisation process resulted in the immobilisation of contaminants as they were locked into the mudcrete.

5

Risk of leaching pollutant material in groundwater

6

Very positive impact in agri beneficial re-use as a soil improver.

7

Positive - cost saving and environmental improvements from removing dumping at sea. Negative - environmental management of the land disposal vehicles and route.

8

Controlled flooding

9

NA

10

Stabilising the sediment meant a smaller carbon footprint when comparing to offshore disposal, using stabilised dredged sediment to create the reclamation resulted in not using precious aggregates from quarries, eliminated hundreds of thousands of truck movements from the quarry to the port.

11

we created new fish reef habitat, helped close a open water disposal site, closed landfills and restored two marsh islands

12

In Belgium a permit is required to dredged. In this permit you have to investigate to possible effects on water, land, environment + possible actions to prevent negative impacts. Also a survey whether the soil is polluted or not is required. It

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is not so easy to get a permit because a lot of things have to be investigated. 13

Positive was the use of a nearby source of sediment for land reclamation; negative was the challenges of fitting the scheduling timelines of a relatively small redevelopment project into that of a large multi-phase land reclamation project.

14

When we beneficially use DM we do not have negative impacts. During operation we have. For example, in the reshaping of gravel pits DM is disposed in the water that will become turbid then.

15

Yes. Prior to commencement of the reclamation works, environmental impact assessments were carried out to determine the impact of the works on the surrounding environment as well as to determine the scope of the plan EMMP. During the construction works, an EMMP will be put in place by appointed specialist consultant to protect the marine environment while allowing works to be carried out. In addition, corals impacted by the work were relocated to suitable sites. The public and NGOs were engaged in the corals relocation work.

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QUESTION 20 Please give a brief description of any positive and negative financial impacts that arose during the beneficial reuse of dredged materials. Respondent

Answer

1

N/A

2

In every case over the past five year, all beneficial uses saved money thus their selections. Clients have turned down some possible beneficial uses due to cost.

3

The use of dredged materials in mudcrete for reclamation purposes resulted in cost savings by removing the need for tug boats and hopper barges to travel great distances to dispose of materials. The use of dredged materials was also substantially cheaper than using quarried material and also saved the cost of transportation costs.

4

In a concept study, we e.g. identified that the gravel could be filtered out and sold in the local concrete industry. Project is ongoing and classified.

5

Permitting costs have just doubled but still very economical compared to haulage and landfill.

6

As per 19

7

Regular cost management meetings were carried out/ briefing

8

NA but i feel if there was more done at SI stage the reuse and would be financially beneficial.

9

The re furbishing of the beaches helps with the tourism

10

In ******** the cost to stabilise is equal to the cost to offshore dispose due to the distance to the offshore dump grounds - so it is cost neutral. As the material in ******** was contaminated it was cost beneficial to stabilise it and put into a reclamation rather than transporting to landfill that could accept the contaminated material.

11

material that had to be placed upland costs between 80-150% more than plain ocean placement, but this was integrated into

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the initial cost estimate and benefit to cost ratio to determine project viability. These costs did not change very much during construction 12

Same as question 19. A permit is required to re-use dredged materials.

13

Positive was the relatively low disposal cost since material was accepted by the Port

14

Treatment is very expensive

15

The benefits derived from the innovative use of these materials, which are wastes generated from dredging, are that it reduces the reliance on sand for reclamation, reduces the need for waste disposal ground for these wastes and savings in fill material cost.

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QUESTION 21 Did your organisation discover any economic advantages or disadvantages during the stabilisation/solidification of DM for BU? Respondent

Answer

1-4

N/A

5

The use of DM in mudcrete for reclamation purposes resulted in cost savings by removing the need for tug boats & hopper barges to travel great distances for materials disposal. The use of DM was substantially cheaper than using QM & saved on transportation costs.

6

Yes, but often the client does not want any risk & client sometimes believe that clays & organic material cannot be used in reclamations.

7

None, but this was the first contract.

8

Yes

9

NA but this could be calculated and compared at outset.

10

The economic disadvantage in most situations is that the stabilisation process limits the production of the dredger resulting in higher dredging costs.

11

No

12

Yes, especially for land reclamation

13

NA

14


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QUESTION 22 Please give a brief description of any positive and negative logistical impacts that arose during the stabilisation/solidification of DM for BU. Respondent

Answer

1-6

N/A

7

Mainly positive impacts, very little negative impacts. Reduced transportation costs in relation to tug boat and hopper barge movement. Also reduced truck movement through the city. Due to the pugmill barge, there was no need to treat the material on land prior to processing of the dredged material, saving time and costs.

8

Compaction can be done after placement and is to not always on critical path.

9

Negative is he transportation by road of the treated material, partly due to poor supply chain but was an issue in a built-up environment.

10

none

11

Usually transportation, the march restoration projects were further way than the ocean placement site. for upland, some areas had significant truck haul distances. We were not able to use rail

12

Positive: you have all the sand for land reclamation on a very cheap way.

13

The efficiency of a dredging operation also is an important factor for the costs (fuel) and sustainability (energy use). So, a complicated logistics should be avoided were possible. Simple solutions are the most beneficial.

14


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QUESTION 23 Did your organisation discover any logistical advantages or disadvantages during the stabilisation/solidification of dredged materials for beneficial reuse? Answer N/A Mainly positive impacts, very little negative impacts. Reduced transportation costs in relation to tug boat and hopper barge movement. Also reduced truck movement through the city. Due to the pugmill barge, there was no need to treat the material on land prior to processing of the dredged material, saving time and costs. Negative is he transportation by road of the treated material, partly due to poor supply chain but was an issue in a built-up environment. Taking materials ashore would have been far more advantageous from a logistical and operational POV. No Yes, there are less settlements, so less damage to pavements etc. NA The benefits derived from the innovative use of these materials, which are wastes generated from dredging, are that it reduces the reliance on sand for reclamation, reduces the need for waste disposal ground for these wastes and savings in fill material cost.

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QUESTION 24 Does your organisation implement a process flowchart to assist with beneficial reuse selection? If so please elaborate below. Respondent

Answer

1-3

No

4-5

N/A

6

Yes, we looked at several alternatives in every project.

7

Generally, we look at the nearest BU option to source & then the simplest & cheapest permitting options for BU, i.e: exemptions. The SI results often dictate our options with regards to contamination issues & BU suitability.

8

Not at present

9

Yes

10

Somewhat. The flow chart would be used to characterize the material as being suitable for what placement type site & how much was available. It then was up to a cost sharing partner to raise their hand & want to do the BU for some type of restoration project

11

No

12

In the USA, BU must be considered as options before material is considered for offshore disposal.

13

We have legislation for the disposal and use of soil, DM & building materials (The soil Quality Decree). So, what to do is more or less prescribed. Aim of the legislation is to protect environment & facilitate reuse (circular economy).

14

Detailed studies were carried out.

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QUESTION 25 Did your organisation conduct any public outreach activities for either dredging consent or application for beneficial reuse of dredged material? Respondent Answer 1-4

No

5-7

N/A

8

Always

9

As a dredging organisation, the public consultation was conducted by the client (Port of *******).

10

Yes

11

The initial project development required public input. Just about every placement option required some type of public notification. Some of the outreach was performed by the cost sharing partner.

12

Yes, we have to follow the EU tender rules for all projects.

13

Prior to commencement of reclamation works, corals impacted by the work were relocated to suitable sites. The public and NGOs were engaged in the corals relocation work.

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