Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, … · 2014-06-03 · Amended EIR...

Proposed Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, DCT, Port of Durban – DEA

Ref: 14/12/16/3/3/2/275

Draft EIA Report i

AMENDED

EIA REPORT

03 June 2014 [NEAS REF NO: DEA/EIA/0000988/2012

DEA REF NO: 14/12/16/3/3/2/275]

Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, Container Terminal, Port of

Durban

P.O. BOX 1673

SUNNINGHILL

2157

147 Bram Fischer Drive

FERNDALE

2194

Tel: 011 781 1730

Fax: 011 781 1731

Email: [email protected]

Amended EIR - Proposed Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, DCT, Port of

Durban (DEA Ref: 14/12/16/3/3/2/275)

ii

EXECUTIVE SUMMARY

Transnet National Port Authority (TNPA) plans to upgrade Berths 203 to 205, Pier 2, Container

Terminal, Port of Durban. Berth 203 to 205 are the key container berths in the Port, however, the

existing Blockwork Quay wall structure along Pier 2 Berth 203 to 205 was designed in the 1970s

to support dockside cranes with the lifting capacity of 4 tonnes. The quay walls are presently

operating beyond their original design limitations. Recent studies have concluded that the existing

quay walls do not meet the minimum Eurocode 7 Safety Standards and that there is a risk of

potential quay wall failure (PRDW, 2011). Vessel sizes have also increased since the original

terminal was constructed and Berth 203 to 205 cannot therefore safely accommodate fully-laden,

new-generation, container vessels due to insufficient water depth at these berths. At present

these vessels enter and exit the Port partially laden and during the high tide window. This creates

an unsafe operating condition and the risk exists that vessels could run aground. TNPA has

proposed the deepening, lengthening and widening of Berth 203 to 205 in order to improve the

safety of the berths as well as to improve the efficiency of the Port.

The proposed upgrade would include the following activities:

The westward lengthening of Berth 205 by 170m;

The eastward lengthening of Berth 203 by 100m;

The seaward widening of Berths 203 to 205 by 50m;

The deepening of the berth channel, approach channel, and vessel turning basin from

the current -12.7m CDP to -16.5m CDP;

Three technical options are to be considered namely, the Caisson option, Sheet Pile

option and Deck on Pile option. In the case of the Caisson option, a trench will need to

be excavated to -19m CDP;

The construction of caissons, storage of sheet piles or precasting of elements of the

Deck on Pile at Bayhead Lot 10;

The offshore disposal of dredge material;

The offshore sand winning for infill material; and

The installation of new Ship to Shore (STS) cranes and associated infrastructure.

Nemai Consulting was appointed by TNPA to undertake the requisite Environmental Authorisation

Process for the Proposed Berth 203 to 205, Pier 2 upgrade. The proposed development

triggers activities listed in Government Notices No. R. 544, R. 545 and R. 546. Hence, a full

Scoping/EIA study, as per the August 2010 Environmental Impact Assessment (EIA)

Regulations promulgated in terms of the National Environmental Management Act, 1998 (Act

No. 107 of 1998) is necessary.


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In addition, a Dumping at Sea Permit as per the National Environmental Management: Integrated

Coastal Management Act, 2008 (Act 24 of 2008), is required to dispose of dredged material at an

offshore disposal site.

A Mining permit for dredging of material offshore for infill purposes will also be required as per the

Mineral and Petroleum Resources Development Act, 2002 (Act No. 22 of 2002).

The final EIA report was submitted to DEA on 5 August 2013. On 21 October 2013 DEA issued a

letter stating that the final EIA report was rejected. DEA requested additional information before a

decision could be taken. There were two main areas which required additional information (Refer

to Appendix A for a copy of the DEA letter dated 05/08/14):

1. Impact on the Central Sandbank; and

2. The Climate Change Study.

The Specialists reviewed existing reports in light of the comments raised by DEA. The following

reports were compiled in response to the DEA letter:

1. Ecological Risk Assessment pertaining to the Estuarine Habitat in Durban Bay by

Extension of the Central Sandbank – Anchor Environmental and CSIR;

2. Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban –

Extension of Sandbank Engineering Risk Assessment Revision D (ZAA

1370/RPT/040REVD) – ZAA Engineering; and

3. Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Design

Report – Effects of Climate Change on Engineering Design Revision F

(ZAA/1370/RPT/028REVF).

On 28 February 2014, the revised reports were presented to the Units within DEA that raised their

concerns. Based on the outcome of the meeting, DEA provided additional correspondence

regarding their requirements on 22 April 2014 (Refer to Appendix A for a copy of the DEA letter

dated 22/04/14).

The aforementioned studies were updated with the latest comments from DEA. The final reports

are contained in Appendix B1-3 and are summarised in Chapter 5 of this report. The findings of

this study have been used to deal with all the comments raised by the DEA. The letters from

DEA, Specialist Studies and the Additional Information Report is available for public review from 2

June 2014 to 2 July 2014 (30 days) to allow all I&APs to provide comments.

The Ecological Risk Assessment Report (Anchor Environmental and CSIR, 2014), concluded that

given the long term engineering stability of the proposed new sandbank habitat, initial

colonisation, succession and the establishment of an ecologically functioning benthic community


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is certain. Further, given the proximity of this sandbank to the existing Central Sandbank and its

similarity in terms of structure, granulometry and hydrodynamic characteristics, it is highly likely

that a similar biological community will develop. Minor differences should be expected and will

probably beneficially increase benthic diversity in the Bay. Successful establishment of benthic

biota will result in profitable utilisation of the created habitat by higher trophic level organisms (fish

and birds). Fish especially will benefit from the creation of additional shallow intertidal and

subtidal habitat. These habitats are the primary feeding areas for juvenile estuarine dependent

species utilising Durban Bay as a nursery. Shallow subtidal area is especially important. The

present configuration and bathymetry of Durban Bay, with a strong predominance of deep water

habitat or intertidal habitat, and limited shallow subtidal habitat, reduces its value as a fish

nursery. Shallow water offers juvenile fishes protection from predation by piscivorous fishes

(Blaber 1987, Ruiz et al. 1993). Such habitat is limited in Durban Bay at low tide, leaving juvenile

fishes susceptible to predation. The proposed sandbank extension results in significant increases

in these shallow water habitats and will fulfil an ecological role that is congruent with the Bay’s

ecological value as an estuarine embayment. Indeed in the long term it will improve the systems

ecological value.

The Extension of Sandbank Engineering Risk Assessment report (ZAA Engineering, 2014a)

summarised the work that has been carried out as part of the FEL‐3 study and has addressed in

particular the engineering issues, with respect to the extension of the central sandbank, raised by

the Department of Environmental Affairs in its letter Ref 14/12/16/3/3/2/275 signed on 21 October

2013 and issued in response to the initial EIA Report, by means of the following:

A comprehensive Risk and Mitigation Analysis covering both the construction of the

extension and the maintenance of the sandbank during the operational phase of the new

container terminal at Pier

Development of a Method Statement for the construction of the sandbank

Hydrodynamic and morphological analyses of the Port of Durban using DELFT‐3D to

determine the short and long term stability and form of the extended sandbank, including

the effects of wave penetration, wind and currents due to tidal movements and other

effects. These studies indicate that the extended sandbank will be stable and that it will

not endanger the stability of the existing sandbank during construction, or during

operation of the container terminal. It also indicates that flows will not change in the area

of the Little Lagoon and this, combined with the sheet pile protection to be installed, will

ensure that the Little Lagoon is not disturbed.

Hydrodynamic analyses have been carried out to assess the levels of turbidity and total

suspended solids (TSS) that will result from the dredging operations and the studies

have confirmed that levels will be within acceptable limits.


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Geotechnical finite element analyses have been carried out using the computer

programme PLAXIS to ensure the stability of the sandbank extension.

An extensive on site geotechnical investigation (involving Cone Penetrometer Testing

with pore water pressure data (CPTu) and proof drilling and logging) has been carried

out to determine the nature and suitability of the sands that will be dredged from the

basin, for use in the construction of the sandbank extension.

Comprehensive dredging analysis and design has been carried out.

This report showed that all risks were mitigated to a ‘’minor’ impact.

The Effects of Climate Change on Engineering Design Report (ZAA, 2014b) reviewed and

summarised available literature on parameters affected by climate change that are relevant to the

marine engineering design for this project. The IPCC, (2013) Climate Change 2013, has been

adopted as the primary reference for this report. This is in agreement with IPCC AR4 (2007),

together with the scaled up ice sheet discharge allowance, projected from 2095 to 2100. This has

been supplemented by guidelines produced by UK Climate Projections Report June 2009

(UKCP09) and the National Committee on Coastal and Ocean Engineering, Engineers Australia.

The parameters listed below are those that can be affected by climate change and are relevant to

the marine engineering design. These parameters have been taken into consideration in the

design of the proposed quays and associated dredging works:

Long term sea level rise

Storm surge (wind setup, pressure deficit, wave setup)

Temperature

Wind (including tropical cyclones)

Currents

Waves

Rainfall

Ocean acidification

The study demonstrates that the chosen cope level of +4.25m CDP is sufficient, providing a

freeboard of 0.324m over and above the allowed for accumulation of various upper bound

increases for climate change affected parameters.

The risks and vulnerability of the new quays to climate change, and in particular sea level rise and

storm surge, have been minimised and that the selected cope height of 4.25 m originally

proposed by Transnet for this project is safe, conservative for its design life of 50 years from the

projected completion date of 2019 and that a safe freeboard will still exist. In fact, given the year

2100 projection values, the structure is likely to be safe for a further 32 years after 2069. In all


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cases this is in the event of the simultaneous occurrence of all factors affecting the water level in

the Port.

Various improbable extreme scenarios (e.g. UKCP09 H++) have been taken into account when

evaluating the design in terms of contingency planning in the event of these extreme scenarios.

Other climate change affected parameters such as wind, rainfall and ocean acidification have

been taken account during the design of the quay structures, storm water system and concrete

specification.

The threat of flooding during the construction phase has been evaluated and we conclude that

construction will not adversely affect the current levels or increase the risk or vulnerability to

flooding.

Based on the additional risk and vulnerability assessment studies undertaken to address DEA’s

comments, the Central Sandbank Extension is deemed a rational and acceptable mitigation

measure that has a high likelihood of success in terms of colonisation and succession. In terms of

engineering design, DELFT-3D models have shown that the Sandbank Extension is stable and

will require no long term maintenance. Mitigation measures have been provided in this Annexure

as well as the monitoring protocol required to determine the baseline thresholds. The Sandbank

Extension has a very low likelihood of failure, however should this happen, the ecological

implications would be similar to the original Option 3C dredge footprint (5.6% loss of habitat and

associated loss of functioning). The biggest socio-economic impact of this loss would be related

to recreational and subsistence fishing (due to the loss of nursery habitat). However, it should be

noted that the Central Sandbank Extension will increase nursery habitat and thus will have a

positive socio-economic impact in this regard.

In regards to Climate Change, risk and vulnerabilities of the Port to changes in Climate have been

taken into account through the engineering design.

Thus, with the selection of the quay wall alternatives, dredge footprint and offshore sand winning

site, the adoption of the mitigation measures included in the Amended EIA Report and original

EIA report and the dedicated implementation of the suite of EMPrs, it is believed that the

significant environmental aspects and impact associated with this project can be suitably

mitigated. With the aforementioned in mind, it can be concluded that there are no fatal flaws

associated with the project and that authorisation can be issued, based on the findings of the

specialists and the impact assessment, through the compliance with the identified environmental

management provisions.

The extension of the Central Sandbank will be monitored over a period of 5 years from the day

the extension is created. Any deviations will be discussed with an Environmental Monitoring

Committee. Should the extension of the sandbank not meet 80% of the baseline conditions then

offset measures will be considered in consultation with DEA.


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TITLE AND APPROVAL PAGE

Project name: Proposed Deepening, Lengthening and Widening of Berth 203 to 205,

Pier 2, Container Terminal, Port of Durban

Report Title: Proposed Deepening, Lengthening and Widening of Berth 203 to 205,

Pier 2, Container Terminal, Port of Durban – Amended EIA Report

Authors: D Naidoo, Vanessa Stippel (nee Brueton), Donavan Henning and R

Maharaj

Additional Specialists: Dr B Clark, Dr. S Weerts and Dr J Zietsman

Authority reference No.: NEAS REF NO: DEA/EIA/0000988/2012, DEA REF NO:

14/12/16/3/3/2/275

Status of report: Draft

Date of issue: 03 June 2014

Prepared By: Nemai Consulting

Client: Transnet National Ports Authority


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AMENDMENT PAGE

Date Nature of Amendment Amendment No. Signature

June 2014 Draft for Public Review 1


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TABLE OF CONTENTS

EXECUTIVE SUMMARY .............................................................................................................. ii

TITLE AND APPROVAL PAGE ................................................................................................. vii

AMENDMENT PAGE ................................................................................................................. viii

TABLE OF CONTENTS .............................................................................................................. ix

LIST OF TABLES ........................................................................................................................ xi

LIST OF FIGURES ...................................................................................................................... xi

LIST OF APPENDICES ............................................................................................................. xiii

LIST OF ACRONYMS AND ABBREVIATIONS ......................................................................... xiv

DEFINITIONS OF KEY TERMS ................................................................................................. xvi

1 PURPOSE OF THIS DOCUMENT ......................................................................................... 19

2 DOCUMENT ROADMAP ....................................................................................................... 20

3 PROJECT MILESTONES ...................................................................................................... 25

4 SUMMARY OF ADDITIONAL SPECIALIST STUDIES .......................................................... 26

4.1 Comments from DEA ............................................................................................................. 26

4.2 Ecological Risk Assessment pertaining to the Estuarine Habitat in Durban Bay by Extension of

the Central Sandbank – CSIR and Anchor Environmental ....................................................... 29

4.2.1 Specialist ................................................................................................................... 29

4.2.2 Main Findings ............................................................................................................ 30

4.3 Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Extension of

Sandbank Engineering Risk Assessment (ZAA1370/RPT/040REVD) – ZAA Engineering ....... 35

4.3.1 Specialist ................................................................................................................... 35

4.3.2 Main Findings ............................................................................................................ 36

4.4 ..... Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Effects of

Climate Change on Engineering Design (ZAA1370/RPT/028REVF) – ZAA Engineering ......... 51

4.4.1 Specialist ................................................................................................................... 51

4.4.2 Main Findings ............................................................................................................ 51


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5 SUMMARY OF RESPONSES PROVIDED ............................................................................ 63

5.1 Central Sandbank .................................................................................................................. 63

5.2 Climate Change Issues .......................................................................................................... 75

5.3 Re-use of Dredge Material ..................................................................................................... 79

5.4 Alien Invasive Species ........................................................................................................... 81

5.5 Stability of the Sandbanks ...................................................................................................... 81

5.6 Mitigation Measures and Monitoring ....................................................................................... 82

6 SUMMARY OF ADDITIONAL MITIGATION MEASURES ..................................................... 96

6.1 Central Sandbank .................................................................................................................. 96

6.1.1 Management and Minimization of Habitat Loss ......................................................... 96

6.1.2 Management of Central Sandbank* ........................................................................... 97

6.1.3 Management of Central Sandbank Dredging ............................................................. 98

6.1.4 Management of Central Sandbank Extension .......................................................... 100

6.1.5 Management of stabilization of the toe of the Extended Sandbank .......................... 101

6.1.6 Offset Plan .............................................................................................................. 101

6.2 Avifauna ............................................................................................................................... 101

6.3 Dredging and Dredge Disposal ............................................................................................ 102

6.3.1 Management of Dredger .......................................................................................... 102

6.3.2 Management of Turbidity ......................................................................................... 102

6.3.3 Management of Transportation of Dredge Spoil to Disposal site ............................. 103

6.3.4 Management of Disposal of Dredge Spoil at the Disposal Site ................................ 104

6.3.5 Management of Ballast Water ................................................................................. 105

6.4 Climate Change ................................................................................................................... 105

6.4.1 Climate Change Adaptation ..................................................................................... 105

6.4.2 Climate Change Mitigation ...................................................................................... 106

6.5 Little Lagoon ........................................................................................................................ 108

6.5.1 Management of Fencing and Restricted Access of Sensitive Environmental Features

108

6.5.2 Management of Little Lagoon .................................................................................. 108


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6.5.3 Management of Turbidity at the Little Lagoon .......................................................... 108

6.6 Monitoring to Mitigate Impacts of Turbidity ........................................................................... 109

7 AMENDED EIA REPORT CONCLUSIONS AND RECOMMENDATIONS ........................... 114

7.1 Best Practicable Environmental Option (BPEO) ................................................................... 114

7.2 Environmental Impact Statement ......................................................................................... 116

7.3 Amended EIA Report Recommendations ............................................................................. 122

8 REFERENCES ..................................................................................................................... 123

LIST OF TABLES

Table 1: Locations for review of Draft EIA Report ........................................................................ 19

Table 2: Document Roadmap of Additional Information Requested by DEA – 21 October 2013 . 20

Table 3: Document Roadmap of Additional Information Requested by DEA – 22 April 2014 ....... 22

Table 4: Summary of Comments and Responses ....................................................................... 63

Table 5. Solubility of oxygen in seawater (mg/L) under constant pressure (one atmosphere) for a

range of salinities and temperatures (Source: DWAFR 1995)........................................ 91

LIST OF FIGURES

Figure 1: CPTU’s and Calibration Borehole Locations ................................................................. 38

Figure 2: Existing configuration at Berth 205 end of Pier 2, prior to Berth Deepening (Note sea

water is removed from the picture for the purposes of clarity ....................................... 41

Figure 3: Dredge Basin and stabilise with scour protection as appropriate and construct sandbank

extension .................................................................................................................... 42

Figure 4: Install new Caisson quay wall....................................................................................... 42

Figure 5: Pre‐Berth Deepening: Long term 50year ‐ Mean total transport ................................... 46

Figure 6: Option‐3H Post‐Berth Deepening: Long term 50year ‐ Mean total transport ................. 47

Figure 7: Section A‐A (Central Sandbank Slope) Analysis .......................................................... 48

Figure 8: Section B‐B (Turning Basin Slope) Analysis ................................................................. 49

Figure 9: Section E‐E (Western Scour Protected Slope) Analysis ............................................... 50


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Figure 10: 1990 to 2100 sea level rise projections (after IPCC, 2001b; 2007b)2 with IPCC (2013)

Climate Change 2013, The Physical Science Basis, Summary for Policy Makers Ref

(16) 0.82 metres at 2100 ............................................................................................. 54

Figure 11: Existing Quaywall ....................................................................................................... 55

Figure 12: Post Construction – Year 2019 ................................................................................... 55

Figure 13: End of Structure Design Life – Year 2069 .................................................................. 56

Figure 14: Post Structure Design Life – Year 2100 ..................................................................... 56

Figure 15. Graphic demonstration of procedures for monitoring environmental impacts and

recovery. ..................................................................................................................... 84

Figure 16: Institutional Arrangements: Roles & Responsibility ..................................................... 85

Figure 17: Preferred Option Combination – Caisson Quay Wall with Option 3G Dredge Footprint.

.................................................................................................................................. 115

Figure 18: Area 1a (Preferred Sand Winning Area (Adapted from Maitland, 2012). .................. 116


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LIST OF APPENDICES

Appendix Description

Appendix A Correspondence from DEA:

1. Letter from DEA dated 21 October 2013

2. Letter from DEA dated 22 April 2014

Appendix B Specialist Studies:

1. Ecological Risk Assessment pertaining to the Estuarine Habitat in

Durban Bay by Extension of the Central Sandbank – Anchor

Environmental and CSIR;

2. Feasibility Study (FEL3) for the Deepening of Berths 203 to 205,

Port of Durban – Extension of Sandbank Engineering Risk

Assessment Revision D (ZAA 1370/RPT/040REVD) – ZAA

Engineering; and

3. Feasibility Study (FEL3) for the Deepening of Berths 203 to 205,

Port of Durban – Design Report – Effects of Climate Change on

Engineering Design Revision F (ZAA/1370/RPT/028REVF).

Appendix C Proof of Notification

1. Emails

2. SMSES


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LIST OF ACRONYMS AND ABBREVIATIONS

AR4 Assessment Report 4

As Arsenic

Cd Cadmium

CDP Chart Datum Port

Chl-a Chlorophyll -a

CO2 Carbon Dioxide

CPTu Pore water pressure

Cr Chromium

CSIR Council for Scientific and Industrial Research

Cu Copper

DEA Department of Environmental Affairs

EA Environmental Authorisation

ECO Environmental Control Officer

EIA Environmental Impact Assessment

EIR Environmental Impact Report

EMC Environmental Management Committee

EMPr Environmental Management Programme

EO Environmental Officer

FEL3 Feasibility 3

GCM General Circulation Model

GHG Greenhouse Gases

GPS Global Positioning Service

Hg Mercury

I&APS Interested and Affected Parties

IAEA International Atomic Energy Agency

IPCC Intergovernmental Panel on Climate Change

Km kilometre

mg milligrams

Ni Nickel


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Pb Lead

RCP Representative Concentration Pathways

SLR Sea Level Rise

STS Ship to Shore

TEU Twenty Foot Equivalent Unit

TNPA Transnet National Ports Authority

TSD Trailing Suction Dredger

TSS Total Suspended Solids

UK United Kingdom

UKCP UK Climate Projections

US United States

Zn Zinc

цm micrometres


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DEFINITIONS OF KEY TERMS

Alternatives In relation to a proposed activity, alternatives refer to the different means of meeting

the general purpose and requirements of the activity, which may include

alternatives to:

The property or location where it is proposed to undertake the activity;

The type of activity to be undertaken;

The design or layout of the activity;

The technology to be used in the activity;

The operational aspects of the activity; and

The option of not implementing the activity.

Bathymetry The sea bed “topography” derived from measurements of depths of water.

Benthic Referring to organisms living in or on the sediments of aquatic, estuarine and

marine habitats.

Benthos The sum total of organisms living in, or on, the sediments of aquatic habitats.

Biodiversity The variety of life forms, including the plants, animals and micro-organisms, the

genes they contain and the ecosystems and ecological processes of which they are

a part.

Biogeochemistry The study of the relationship between geochemistry of a region and the biology in

that region.

Biomass The living weight of a plant or animal population, usually expressed on a unit area

basis.

Biota The sum total of the living organisms of any designated area.

Chart Datum A reference point linked to the low water mark (ordinary spring tide) and used for

measuring sea water depth. In South Africa, a unique Chart Datum is identified for

each port. Chart Datum is defined by the Hydrographer as 0.913 metres below land

levelling datum.

Chart Datum Port Chart Datum Port is defined by Transnet National Port Authority as 0.900 metres

below land levelling datum.

Community An assemblage of organisms characterized by a distinctive combination of species

occupying a common environment.

Community

composition

All the types of taxa present in a community.

Community

structure

All the types of taxa present in a community and their relative abundances.


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Contaminant Biological (e.g. bacterial and viral pathogens) and chemical introductions capable of

producing an adverse response (effect) in a biological system, seriously injuring

structure and/or function.

Cope Line The outer edge of the quay wall.

Crustacea A highly diverse class of organisms containing crabs, shrimps, lobsters, isopods,

amphipods etc.

Detritus Unconsolidated sediments composed of both inorganic and dead and decaying

organic material.

Dewatering To remove water from an object, in this case sediment.

Dragline An excavating machine with a digging bucket attached by cables to a long jib and

operated by being dragged back toward the machine by another cable.

Echinoderms Phylum of marine invertebrates that includes sea urchins, starfish, brittle stars, sea

cucumbers. All are characterized by tube feet and five-part radially symmetrical

bodies.

Endangered A taxon is regarded as endangered when it faces a high risk of extinction in the wild.

This is defined as a 20% probability of extinction within 20 years.

Environment The biophysical, social, economic, cultural, political and historical context within

which people live and within which development takes place.

Environmental

impact

A change resulting from the effect of an activity on the environment, whether

desirable or undesirable. Impacts may be the direct consequence of an

organisation’s activities or may be indirectly caused by them.

Environmental

impact

assessment

Environmental Impact Assessment means a systematic process of identifying,

assessing and reporting environmental impacts associated with an activity.

Epifaunal Organisms, which live at or on the sediment surface being either attached (sessile)

or capable of movement.

Habitat The place where a population (e.g. animal, plant, micro-organism) lives and its

surroundings, both living and non-living.

Infauna Animals of any size living within the sediment. They move freely through interstitial

spaces between sedimentary particles or they build burrows or tubes.

Interested and

affected party

Individuals or groups concerned with or affected by an activity and its

consequences. These include the authorities, local communities, investors, work

force, consumers, environmental interest groups and the general public.

Isopod Any of various small terrestrial or aquatic crustaceans with seven pairs of legs

adapted for crawling.

Lithogenic Derived from rocks and/or soils

Macrofauna Animals which are greater than 1 mm.


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Macrophyte A member of the macroscopic plant life of an area, especially of a body of water;

large aquatic plant.

Molluscs A phylum of organisms containing snails, mussels, oysters.

Piscivorous Feeding on fishes.

Pollution The introduction of unwanted components into waters, air or soil, usually as result of

human activity; e.g. hot water in rivers, sewage in the sea, oil on land.

Population Population is defined as the total number of individuals of the species or taxon.

Recruitment The replenishment or addition of individuals of an animal or plant population

through reproduction, dispersion and migration.

Re-suspension A renewed suspension of particulates.

Sediment Unconsolidated mineral and/or organic particulate material.

Significant impact An impact that by its magnitude, duration, intensity or probability of occurrence may

have a notable effect on one or more aspects of the environment.

Sipunculids Small unsegmented marine worm that when disturbed retracts its anterior portion

into the body giving the appearance of a peanut.

Species A group of organisms that resemble each other to a greater degree than members

of other groups and that form a reproductively isolated group that will not produce

viable offspring if bred with members of another group.

Suspended

material

Total mass of material suspended in a given volume of water, measured in mg/l.

Taxon (Taxa): Any group of organisms considered to be sufficiently distinct from other such groups

to be treated as a separate unit (e.g. species, genera, families).

Toxicity The inherent potential or capacity of a material to cause adverse effects in a living

organism.

Turbidity Turbidity is the attenuation of light in water caused by the sum of suspended

particles and any dissolved chemicals in the water which may alter the passage of

light through scattering (generally inorganic and organic particles) and/or absorption

(generally particulate or dissolved biological material).

Vulnerable A taxon is vulnerable when it is facing a medium risk of extinction in the wild in the

medium-term future, defined as a 10% probability of extinction within 100 years.

Amended EIR - Proposed Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, DCT,

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1 PURPOSE OF THIS DOCUMENT

On 05 August 2013 the final Environmental Impact Assessment (EIA) Report was submitted

to the Department of Environmental Affairs (DEA) for review and authorisation. On 21

October 2013 Nemai Consulting received a letter from DEA stating that the final EIA report

was rejected. The Department requested additional information before it could make a

decision. Refer to Appendix A for a copy of the letter dated 21/10/14.

The Specialists presented the revised reports to DEA on 28 February 2014. Subsequently,

DEA provided additional correspondence regarding their requirements in a letter dated 22

April 2014. Refer to Appendix A for a copy of the DEA letter dated 22/04/14.

The purpose of the Amended EIA Report is twofold:

1. To fulfil the requirements raised DEA in the letters dated 21 October 2013 and 22

April 2014; and

2. To allow Registered Interested and Affected Parties an opportunity to review the

Amended EIA Report for a period of 30 day from 03 June 2014 to 03 July 2014

This Amended EIA Report is available for public review on the project website

(www.berth203to205expansioneia.co.za).

It is also available at the following locations:

Table 1: Locations for review of Draft EIA Report

No. Location Address Tel. No.

1. The Seafarers Club 1 Seafarers Road, Bayhead, Durban 031 466 1326

2. Central Reference

Library - Durban

10th Floor, Liberty Towers, 214 Dr Pixley

KaSeme Street, Durban 031 322 4414

http://www.berth203to205expansioneia.co.za/



20

2 DOCUMENT ROADMAP

The Document Roadmap below provides details on how the comments raised by DEA were

taken into account in the Amended EIA Report. The purpose of this table is to ensure that all

DEA’s requests have been met.

Table 2: Document Roadmap of Additional Information Requested by DEA – 21 October 2013

Chapter Title Requirement from DEA

(21/10/2013) Details of how comment

has been addressed Included

1. Purpose of this Document

– –

2. Document Roadmap – –

3. Summary of Additional Specialist Studies

What are the baseline and thresholds of acceptable change against which monitoring will take place? Ecological Risk

Assessment pertaining to the Estuarine Habitat in Durban Bay by Extension of the Central Sandbank – CSIR and Anchor Environmental Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Extension of Sandbank Engineering Risk Assessment Revision D (ZAA 1370/RPT/040REVD) – ZAA Engineering

What actions are proposed should the monitoring results detect change?

What are the socio-economic and ecological implications should the proposed mitigation measure prove unsuccessful?

Consideration must be given on how realistic and practical the mitigation measure is. Consideration must be given on what costly commitment and assurances have been provided by the applicant.

Gaps, uncertainties and assumptions must clearly be reported.

Climate Change Risks such as sea level rise and storm surges must be addressed.

Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Design Report – Effects of Climate Change on Engineering Design Revision F (ZAA/1370/RPT/028REVF).

Climate Change Risk and Vulnerability Assessment to adequately address how sea level rise and coastal storm surges will be addressed during construction and operational phase of the proposed development



21




4. Summary of Responses

What are the baseline and thresholds of acceptable change against which monitoring will take place?

What actions are proposed should the monitoring results detect change?

What are the socio-economic and ecological implications should the proposed mitigation measure prove unsuccessful?

Consideration must be given on how realistic and practical the mitigation measure is. Consideration must be given on what costly commitment and assurances have been provided by the applicant.

Gaps, uncertainties and assumptions must clearly be reported.

Climate Change Risks such as sea level rise and storm surges must be addressed.

Climate Change Risk and Vulnerability Assessment to adequately address how sea level rise and coastal storm surges will be addressed during construction and operational phase of the proposed development

Long Term Maintenance burden must be considered.

Provided in Summary of Responses

5. Additional Mitigation Measures

- -

6. Conclusions and Recommendations

- -

Appendix A – Letter from DEA

Appendix B – Additional Specialist Study Reports

Appendix C – Proof of Public Participation

You are required to amend the EIA report to include the above and make the amended report available to all registered interested and affected parties for a 30 day commenting period.

A 30 Day public review period will be provided. All proof of notification to registered I&Aps is provided.

Appendix D – Comments and Responses

All comments received during the review period will be submitted to DEA.

In final Report

Table 3 contains the requirements of the DEA set out in the letter dated 22 April 2014.



22

Table 3: Document Roadmap of Additional Information Requested by DEA – 22 April 2014




1. Purpose of this Document

– –

2. Document Roadmap – –

3.

Summary of Additional Specialist Studies

Re-use of dredging material is international best practice. The report should provide examples and references thereof.

Ecological Risk Assessment pertaining to the Estuarine Habitat in Durban Bay by Extension of the Central Sandbank – CSIR and Anchor Environmental

Consideration must be given to the chemical pollutants of the dredge material.

Information regarding climate risks, sea level rise impacts and storm surges must be included in the report.

Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Design Report – Effects of Climate Change on Engineering Design Revision F (ZAA/1370/RPT/028REVF).

4.

The stability of the newly created sandbank and cutaway were exhausted tested and it was found that the new design would be more stable than the current layout.

Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban – Extension of Sandbank Engineering Risk Assessment Revision D (ZAA 1370/RPT/040REVD) – ZAA Engineering

5.

The revised report should provide examples and references showing that there are no risks regarding the establishment of alien invasive species.

Ecological Risk Assessment pertaining to the Estuarine Habitat in Durban Bay by Extension of the Central Sandbank – CSIR and Anchor Environmental

6. Summary of Responses

The report should provide examples and references of reuse of dredging; Consideration must be given to the chemical pollutants of the dredge material; Information regarding climate risks, sea level rise impacts and storm surges must be included in the report; The stability of the newly created sandbank and cutaway were exhausted tested and it was found that the new design would be more stable than the current layout; The revised report should provide examples and references showing that there are no risks regarding the establishment of alien invasive species; and Mitigation measures to be provided.

Provided in Summary of Responses

7.

Additional Mitigation Measures

Quarterly or more frequent monitoring would be undertaken for 5 years

Provided in the Summary of additional mitigation measures Silt levels in the water column must

be maintained at ‘moderate’ levels



23




and silt screens must be used while dredging wherever possible

The little lagoon would be specially protected during construction and afterwards

Minimized disturbance on sandbanks during construction including:

No construction workers allowed on Sandbank;

Dredging within 100m of the Sandbank to be undertaken during winter;

No dredging to be done at night;

Dredging within a 100m should be done as far as possible at only site at a time;

A significant portion of Central Sandbank must remain untouched during dredging;

Qualified Environmental Offices need to monitor construction activities;

Reporting to the DEA must be frequent and reporting of disturbances must be almost in a real time basis; and

If mitigation and rehabilitation measures fail then offset measures need to be discussed.

Specific mitigation procedures will need to form part of the Dumping at Sea Permits. New best practices measures and standards gazetted in 2012 must be used in the assessment of the Dumping at Sea Permit.

A monitoring programme should include sandbank morphology, sediment granulometry and organic content, benthic macrofauna, avifauna and levels of pollutants. Monitoring must be undertaken intensely for 2 years and continue less intensely for another 3 years.

Adaption and mitigation measures which may be of importance to infrastructure (in terms of climate change) must be addressed.

8. Conclusions and Recommendations

- -

Appendix A – Correspondence from DEA (21 October 2013 and 22 April 2014)

Appendix B – Additional Specialist Study Reports



24




Appendix C – Proof of Public Participation -

-

Appendix D – Comments and Responses

-



25

3 PROJECT MILESTONES

The following milestones have been reached to date during the EIA process:

1. The Application for Environmental Authorisation was submitted to the

Department of Environmental Affairs (DEA) on 10 February 2012.

2. DEA approved the Scoping Report on 27 August 2012.

3. The final EIA report was rejected by the DEA on 21 October 2013. The DEA

requested additional information on the Central Sandbank and Climate Change

issues.

4. Additional specialist studies were undertaken. This information was presented to

the DEA on 28 February 2014. A letter provided by the DEA on 22 April 2014

provides a summary of the discussions and additional information requirements.

5. The Additional Information Report, Specialist Studies and Correspondence from

DEA are available for public review for a period of 30 days (03 June 2014 to 03

July 2014).



26

4 SUMMARY OF ADDITIONAL SPECIALIST STUDIES

4.1 Comments from DEA

The comments received from DEA on 21 October 2013 can be summarised as follows:

Central Sandbank Information Requests

• What are the baseline and thresholds of acceptable change against which

monitoring will take place?

• What actions are proposed should the monitoring results detect change?

• What are the socio-economic and ecological implications should the proposed

mitigation measure prove unsuccessful?

• All the potential risks and mitigation measures associated with the creation of the

Portion of Central Sandbank as a mitigation measure must therefore be fully

assessed and be addressed in the amended report.

• Consideration must be given on how realistic and practical the mitigation

measure is.

• Consideration must be given on what costly commitment and assurances have

been provided by the applicant.

• Gaps, uncertainties and assumptions must clearly be reported.

• Long Term Maintenance burden must be considered.

In order to address these comments the following two studies were compiled and are

summarised in Chapter 5.2 and 5.3.


Extension of the Central Sandbank – Anchor Environmental and CSIR; and

2. Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban

– Extension of Sandbank Engineering Risk Assessment Revision D (ZAA

1370/RPT/040REVD) – ZAA Engineering.

Climate Change Information Request

• Climate Change Risks such as sea level rise and storm surges must be

addressed.

• A Climate Change Risk and Vulnerability Assessment to adequately address

how sea level rise and coastal storm surges will be addressed during

construction and operational phase of the proposed development.



27

To address these comments, one additional study was undertaken:


– Design Report – Effects of Climate Change on Engineering Design Revision F


This report is summarised in Chapter 5.4.

The comments received from DEA on 22 April 2014 can be summarised in the following

manner:

Re-Use of Dredge Material

• Re-use of dredging material is international best practice. The report should

provide examples and references thereof.

• Consideration must be given to the chemical pollutants of the dredge material.






Extension of Sandbank Engineering Risk Assessment Revision D (ZAA


Climate Change

• Information regarding climate risks, sea level rise impacts and storm surges must

be included in the report.

• Mitigation measures to be provided.

To address these comments, one additional study was undertaken:


Design Report – Effects of Climate Change on Engineering Design Revision F


This report is summarised in Chapter 5.4.



28

Mitigation Measures and Monitoring

• Quarterly or more frequent monitoring would be undertaken for 5 years

• Silt levels in the water column must be maintained at ‘moderate’ levels and silt

screens must be used while dredging wherever possible

• The little lagoon would be specially protected during construction and afterwards

• Minimized disturbance on sandbanks during construction including:

o No construction workers allowed on Sandbank;

o Dredging within 100m of the Sandbank to be undertaken during winter;

o No dredging to be done at night;

o Dredging within a 100m should be done as far as possible at only site at a

time;

o A significant portion of Central Sandbank must remain untouched during

dredging;

o Qualified Environmental Offices need to monitor construction activities;

o Reporting to the DEA must be frequent and reporting of disturbances must

be almost in a real time basis; and

o If mitigation and rehabilitation measures fail then offset measures need to

be discussed.

• Specific mitigation procedures will need to form part of the Dumping at Sea

Permits. New best practices measures and standards gazetted in 2012 must be

used in the assessment of the Dumping at Sea Permit.

• A monitoring programme should include sandbank morphology, sediment

granulometry and organic content, benthic macrofauna, avifauna and levels of

pollutants. Monitoring must be undertaken intensely for 2 years from the day

when the sandbanks are created and continue less intensely for another 3 years.

• Adaption and mitigation measures which may be of importance to infrastructure

(in terms of climate change) must be addressed.






– Extension of Sandbank Engineering Risk Assessment Revision D (ZAA




29


– Design Report – Effects of Climate Change on Engineering Design Revision F


Mitigation measures have been discussed in all three studies. Further, a summary of

mitigation measures regarding dredging, Central Sandbank, Little Lagoon, Avifauna etc. will

be included in Chapter 7.

4.2 Ecological Risk Assessment pertaining to the Estuarine Habitat in Durban Bay

by Extension of the Central Sandbank – CSIR and Anchor Environmental

4.2.1 Specialist

Specialists

Organisation: Anchor Environmental Coastal Systems Research Group, CSIR

Name: Dr Barry Clark Dr Steven Weerts Dr. Brent

Newman

Qualifications: Ph.D. Marine Biology, 1997, University of

Cape Town

BSc (Hons) Marine Biology, 1991, University

of Cape Town

PhD. - PhD

No. of years

experience:

21 18 17

Affiliations Professional Natural Scientist, registered

with the South African Council for Natural

Scientific Professions

Professional member of the South African

Institute of Ecologists and Environmental

Scientists

South African representative to the

SURVAS Network

Member of the International Association

of Impact Assessors

Member of the Subsistence Fisheries Task

Group

Member of the Subsistence Fisheries

Advisory Group

Member of the South African Network for

Coastal and Oceanic Research (SANCOR)

Economics Task Team

CERM N/A



30

4.2.2 Main Findings

This section provides a summary of baseline thresholds and ecological risks of the Central

Sandbank Extension (CSIR and Anchor Environmental, 2014), as contained in Appendix

B1.

4.2.2.1 Summary of the EIA Ecological Assessment:

A summary of the Ecological Assessment undertaken during the EIA including the Anchor

Environmental, 2012a, 2012b and 2012c as well as CSIR, 2012a and b. was provided. The

most salient points are listed below:

The ecological assessment addressed all risks to major fauna and flora groups

such as microalgae (phytoplankton), invertebrates (benthic invertebrates and

zooplankton), fish and birds.

Risks to macrophytes (such as mangroves) were deemed negligible.

Quantitative assessments of habitat losses and gains were undertaken and

initially the only tidal banks to be impacted were the Central Sandbank and the

Little Lagoon. This involved the loss of intertidal sandflat as well as sloping

subtidal sandbank. Losses due to scour protection were also noted.

Mitigated design options resulted in Option 3H which had the lowest impact in

terms of habitat losses and resulted in a slight increase in Sandbank habitat

through the Sandbank extension.

Low intertidal and shallow subtidal sandbank habitats have high value in terms of

nursery habitat for estuarine fishes and crustaceans. Option 3H results in gains

in these areas.

Changes in hydrodynamics were found to result in some changes to bed sheer

stressed. However in terms of structural changes to benthic habitats these are

largely insignificant except in the area near the Berth 205 which is expected to

become coarser in nature.

Results indicated that changes in water fluxes associated with the development

across most of the Port would be minimal and significant long term changes ti

water and sediment quality were deemed unlikely.

Although Option 3H would result in a modified ecosystem functioning in

comparison to the present layout, its residual impact would be neutral if the

Sandbank extension was successful and may even result in a residual positive

impact.



31

Potential impacts associated with elevated suspended sediment concentrations

in the water column and toxicity of heavy metals, hydrocarbons and

polychlorinated biphenyls were also assessed. The findings showed that the

concentrations of metals and organic chemicals in sediment within and near the

dredge footprint were very low and thus there was a very low probability that

chemicals released during the dredging process would be present in the water

column at toxic levels.

Hydrodynamic modelling to assess the impact of suspended sediment

concentrations in the water column were also undertaken. The findings show that

the concentrations would reach 80mg/l in the immediate vicinity of the dredge

head but at the Central Sandbank, concentrations would not exceed 50mg/l

which is in the medium risk category for microalgae, invertebrates and fish.

Due to the fact that suspended sediment concentrations along the east coast

estuaries are naturally higher than in coastal waters and thus local fauna tend to

be quite tolerant of these conditions, it was concluded that 50mg/l would be in a

low significance range (although sediment concentrations should be carefully

monitored).

4.2.2.2 Ecological Risk Assessment – Baseline Thresholds of Acceptance Change

Baseline thresholds need to be established in order to confirm the defined

maximum/minimum water quality thresholds, to confirm the biotic community composition on

the existing sandbank and to allow comparisons after the sandbank extension which show

whether the extension has been successful.

These thresholds will be determined from ecological baseline data that will be collected over

a period of 12-24 months prior to the start of the project.

The baseline assessments will focus on the following components:

Physico-chemical (habitat) variables:

Total Suspended Solids (TSS);

Salinity;

Temperature;

Dissolved Oxygen;

Sediment Grain Size Distribution;

Organic Carbon Content; and

Trace metal content in sediment (Cd, Hg, As, Cr, Cu, Pb, Ni, Zn).



32

Faunal and floral assemblages:

Benthic microalgae (microphytobenthos);

Benthic macrofauna;

Ichythyfauna; and

Avifauna.

Please note the variables in bold and underlined agree with the recommendations of the

DEA Letter – 22 April 2014. All other variables are included as additional requirements.

The methods for obtaining these baseline data was described in detail and can be reviewed

in the Specialist report in Appendix B1.

Details on primary impact vector was also provided as well as the general baseline values.

The main impact is expected to be levels of suspended sediment and/or organic material in

the water column which affect living organisms by reducing levels of dissolved oxygen in the

water column. Based on Steffani et al. (2003), low risk is seen to be <20mg/l; medium risk is

seen to be 20mg/l-80mg/l and high risk is >80mg/l.

Based on this, during construction phase, monitoring will ensure that suspended solids

remain below 50mg/l and that oxygen levels do not drop below 5mg/l (99% of the time or

more than 1 minute in every 60 minutes) or 6mg/l (95% of the time or 3 minutes in every 60

minutes). Should the monitoring show that turbidity or dissolved oxygen exceed these

recommendations, then dredging will stop until levels have declined below this point. Silt

curtains are also recommended should these thresholds be frequently exceeded. In addition,

choking of the dredge hopper overflow is also suggested so that the fluid level in the hopper

is maintained and as a result no air is taken down with the suspension leaving the hopper.

The approach for assessing the rate of recovery of the newly created portion of the Central

Sandbank is also provided and will be based on the concept of bioequivalence. The number

of species, abundance and/or biomass of the organisms in question at the rehabilitation site

should be at least 80% of the measured pre-impact baseline levels (and/or those at

comparable control stations) and must remain this way for at least two years before the site

can be considered rehabilitated. Monitoring will take place for at least 5 years.

4.2.2.3 Ecological Risk Assessment – What actions are proposed if the monitoring

results detect change?

As discussed above, the main impact during the construction phase is related to turbidity

and dissolved oxygen.



33

However, a number of mitigation measures have been provided and suspended solids will

be controlled in three ways.

The dredge hopper overflow will be choked with a fully automated computerised

process controller to ensure that there is a constant fluid level in the hopper is

maintained and thus no air is taken down with the suspension. This has been

shown to significantly decrease turbidity in surrounding waters.

The concentration of suspended solids in the Bay area will also be controlled via

the use of silt curtains.

Monitoring is the last measure. Should the monitoring show that these levels

exceed acceptable levels, then dredge operations will be halted immediately until

levels have declined below threshold levels.

4.2.2.4 Ecological Risk Assessment – What are the socio-economic and ecological

implications should the proposed mitigation measure prove unsuccessful?

In the event that the proposed mitigation measure (i.e. Sandbank extension) proves

unsuccessful, the estimated impact is estimated to be equivalent to those associated with

Design Option 3C which was originally assessed in the EIR. This would result in a net loss of

6.4% of existing intertidal and subtidal area. High intertidal area near the Little Lagoon would

be lost (14.2%) but offset by an increase in low intertidal area (1.3%) resulting in a zero net

loss of tidal sandbank at the Little Lagoon.

Losses of sandbank would also result in further losses of ecological goods and services as

the sandbank habitat in Durban Bay has already been reduced to only 14% of its original

extent.

At best, the ecological losses would be directly proportional to the habitat losses (i.e. 5.6%

loss of sandbank will result in a 5.6% loss of associated ecological function). This impact

may however be disproportionally large due to the fact that so much of this habitat has been

affected in the past.

Socio-economic implications are difficult to predict as the socio-economic benefits cannot be

explicitly quantified. The primary value of the sandbank habitats is their ecological function

as estuarine nursery habitat and thus the primary socio-economic benefit is related to

recreational and subsistence fisherman. The planned habitat development would increase

this habitat and would likely have a positive socio-economic benefit.



34

4.2.2.5 Ecological Risk Assessment associated with the creation of a Portion of

Central Sandbank

Ecological risk assessment relies on sound ecological rationale and knowledge of habitats

and species involved, review of available scientific literature and consideration of appropriate

case studies.

The ultimate measure of ecological success is whether or not the habitat is used beneficially

by the appropriate biota and fulfils its intended function. In Durban Bay, the invertebrate

benthic fauna are fundamental and the main issues that need to be assessed is will the

colonisation take place naturally?, how long will it take?, in what abundance will species

establish populations? And will succession to a functional ecological community take place

naturally?

In the context of this study, the majority of biota typical of the sandbank habitat have pelagic

larval forms that are widely dispersed in the water column by currents. Thus in Durban Bay,

a ready source of larvae is available for colonisation of the newly created suitable habitat

(Section 5.3 will provide more detail on the engineering design of this suitable habitat). The

sandprawn, Callichirus kraussi, does not have a planktonic larval stage but relies on young

which are hatched and developed in parent burrows and then tunnel off of these burrows. A

post-larval dispersive stage does occur however and quick generation times and strong

recruitment are indicative that C. kraussi would recruit strongly onto the newly created

sandbank habitat with high confidence.

Colonisation by invasive alien species is not predicted to be a threat due to the high salinities

in the area as well as the fact that one of the main invasive species required hard surfaces

and thus will not colonise sandbank habitat.

Further, due to the proximity of the new sandbank to the original sandbank as well as the

fact that the proposed sandbank extension will be created using locally sourced material

provide further surety of the ecological success of the extension. In addition, sediments

which have to be removed from the Central Sandbank unavoidably, will be used to ‘cap ‘the

newly created habitat and will contain invertebrates which will fast-track the process.

Numerous experimental studies as well as field studies suggest that benthic colonisation will

take between 3 months and 2 years. A number of studies are explained in more detail in the

Specialist Study.

Examples of local engineered estuarine habitats are provided. The first is that of the

Mhlathuze Estuary. Tidal changes brought about by changes in tides resulted in a huge

increase in the mangroves of the area. The Little Lagoon in the Port of Durban is also known

as a biodiversity hotspot however, this area was artificially created in the 1970s by the



35

expansion of Port facilities which truncated a shallow channel through the sandbanks and

thus created an open basin.

Based on the long term engineering stability, the initial colonisation, succession and

establishment of an ecologically functioning benthic community is certain. Further, given the

proximity of the sandbank to the existing sandbank and its similarity in terms of structure,

granulometry and hydrodynamic characteristics, it is highly likely that a similar biological

community will develop. Successful establishment of benthic biota will result in profitable

utilisation of the created habitat by birds and fish. It will also provide shallow juvenile feeding

areas. The current bathymetry of the Bay has a strong predominance of deep water or

intertidal habitat and shallow subtidal habitat is limited which reduces the nursery function of

the Bay. The proposed extension will thus fulfil an ecological role that is congruent with the

Bay’s ecological value as an estuary and thus in the long term will improve the system’s

ecological value.

4.3 Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban –

Extension of Sandbank Engineering Risk Assessment (ZAA1370/RPT/040REVD)

– ZAA Engineering

4.3.1 Specialist

Specialist

Organisation: ZAA Engineering Projects and Naval Architecture (Pty) Ltd

Name: Dr John Zietsman

Qualifications: BSc (CivEng), UCT, MSc (Ocean Eng) University College London, PhD

University of London

No. of years experience: 39

Affiliations PrEng,

FSAICE,

MICE,

MRINA (overseas),

MSNAME,

FSAAE,

CEng



36

4.3.2 Main Findings

This section provides a summary of the Sandbank Extension Risk Assessment. It also

provides details on the proposed design of the Sandbank as well as the findings of key

modelling studies. The full report is contained in Appendix B2.

This report summarised the work that has been carried out as part of the FEL3 study and

has addressed in particular the engineering issues, with respect to the extension of the

central sandbank, raised by the Department of Environmental Affairs in its letter Ref

14/12/16/3/3/2/275 signed on 21 October 2013 and issued in response to the initial EIA

Report, by means of the following:

A comprehensive Risk and Mitigation Analysis covering both the construction of

the extension and the maintenance of the sandbank during the operational

phase of the new container terminal at Pier


Hydrodynamic and morphological analyses of the Port of Durban using DELFT‐

3D to determine the short and long term stability and form of the extended

sandbank, including the effects of wave penetration, wind and currents due to

tidal movements and other effects. These studies indicate that the extended

sandbank will be stable and that it will not endanger the stability of the existing

sandbank during construction, or during operation of the container terminal. It

also indicates that flows will not change in the area of the Little Lagoon and this,

combined with the sheet pile protection to be installed, will ensure that the Little

Lagoon is not disturbed.

Hydrodynamic analyses have been carried out to assess the levels of turbidity

and total suspended solids (TSS) that will result from the dredging operations

and the studies have confirmed that levels will be within acceptable limits.



An extensive on site geotechnical investigation (involving Cone Penetrometer

Testing with pore water pressure data (CPTu) and proof drilling and logging) has

been carried out to determine the nature and suitability of the sands that will be

dredged from the basin, for use in the construction of the sandbank extension.




37

This report has demonstrated how the Risk and Mitigation Process will be managed and how

all the technical engineering risks have been and will continue to be managed to

internationally acceptable levels.

4.3.2.1 Quantities and Materials

The estimated quantity of sand to be dredged and placed is approximately 1,300,000 m3.

Based on the geotechnical investigations that have been conducted, in particular as

recorded in ZAA 1370‐RPT‐031 ‐ Soil Material for Reclamation of the Central Sandbank, it is

expected that approximately 300,000 m3 of this sand will be newly reclaimed material from

the designated off‐shore borrow areas and the major portion of 1,000,000 m3 will come from

material selected from the dredging of the basin to ‐16,5 m CDP. This should result in

efficiencies of scale and time, as it removes the requirement for each load of dredged

material to be dumped out to sea and in turn material to be imported at a later stage for

reclamation. The area circled in red below has been shown to have suitable sand/silt/clay

mix of approximately 90% sand and 10% silt/clay to a depth of approximately 6m below

seabed level for use in building the extension of the sandbank. The volume associated with

the outline area is approximately 600,000 cubic metres. Approximately 400 000 cubic metres

of suitable material will also be available from the existing fill and sandbank area that will be

excavated and dredged for the proposed extension to Berth 205.



38

Figure 1: CPTU’s and Calibration Borehole Locations

The maximum fines content (smaller than 63 μm) of the material used for hydraulically

placed fill is usually limited to approximately 10% for load bearing fill (Ref. 6 of Report 1370‐

RPT‐031). However since the reclaimed area has no bearing load other than its own self‐

weight which is further reduced due to the slope being submerged, the above percentage

may be increased to a level of less than 30%, On the basis described above, the clay‐rich

zones are excluded and sand‐rich zones are identified as potential borrow sources for

reclamation. To the greatest extent possible, the sediment texture (grain size and sorting) is

critical for success and sand fill must be compatible with native sandbank sand.

This requirement applies to fill as delivered to the reclamation site, and not necessarily to in‐

situ material in the borrow area. Sampling on‐board the dredgers to check the grading of

material is required to confirm that the required specification for fill delivered to the site is

satisfied. Samples shall also be taken at the reclamation site, to check if segregation of

material has occurred during placing, with a view to ensuring that the fines are well

distributed within the reclamation.



39

4.3.2.2 Summary of Sandbank Creation Method

The method of dredging and construction of the sandbank extension may therefore be

summarized as follows:

Set up a survey programme, determining setting out points of the area to be

filled. This must be compared with previous surveys and the baseline agreed.

Conduct a video survey of the existing slopes for record purposes.

Set up pollution control measures – refer to Section 7.2 below.

Install sheet piling at the Berth 205 extension end of Pier 2 to ensure that the

central sandbank and the little lagoon area are secured from any disturbance.

Mobilize and commission suitable dredging equipment, marine operating staff,

diving crews and support boats. The anticipated dredging equipment is a Trailing

Suction Dredger (TSD), fitted with discharge pumps and floating hoses from a

bow coupling.

Dredge clean reclaim material from designated and approved borrow site

offshore or as part of other dredging work for the project.

Provide samples for confirmation of suitability of material on a continuous basis

through laboratory grading analysis

Place sandbags along the line of the new toe of the extended sandbank to form

a low retaining structure. Bio‐degradable sandbags will be used

Place a further row of sandbags along the existing toe of the sandbank at the ‐

12.8 m CDP level. This is intended to prevent material flowing down the slope at

too fast a rate and flowing outwards along the bottom. More than one row of

these bags may be required

Set up silt curtains as described below

Provide diffusers at the ends of hoses to reduce flow velocities and prevent

scouring

Pump the reclaim material from the dredger through floating hoses along the line

of the present top edge of the sandbank. Monitor the deposition of sand behind

the sandbag retaining structure in a sequence so that the area is filled evenly in

layers along the face of the sandbank and rises in layers from below. This

procedure will reduce entrainment of sand in the water column and thus reduce

turbidity.



40

Controlled even placement of thin layers of fill on the reclamation site is

necessary to avoid shear failure of the underlying layers and the formation of

mud waves.

Layers will be staggered, with control being exercised to ensure a sufficient

leading edge for the underlying layer in relation to the layer being formed

Monitor turbidity in the water column and adjust deposition rates or suspend

operations as needed.

Fill to the pre‐determined level, with periodic dives providing video records of the

new profile.

Conduct interim and acceptance surveys for confirmation of final levels achieved

and for measurement of quantities.

The dredged material will be placed on the area of extension of the sandbank in sections

confined by means of silt curtains. These silt curtains will have the following properties:

Sourced from reputable manufacturers with a proven track record.

Designed for the specific application and shall follow the manufacturer’s

recommendations and guidelines for setting up and maintaining such items as

well as guidelines for installation and safety measures.

For use in areas where tidal currents are present

Curtains will be deployed so that the size of individual paddocks will not exceed

one week’s work.

Curved shapes will be preferred as they are less susceptible to wave damage.

Curtains will be extended to the bottom of the waterway in tidal or moving water

conditions, a heavy woven permeable filter fabric or tide flaps shall be designed

into the curtain to relieve pressure on the curtain wall.

Silt curtains will only be used in conditions of slow to moderate currents, stable

water levels, and relatively shallow water depths.

Operations within silt curtains will not continue in current velocities greater than 2

knots unless there are unusual circumstances, as in all but the slowest current

flows, curtains will billow out in the downstream direction, allowing water to pass

beneath the curtain, thereby reducing the effective skirt depth.

Extra length (up to 10‐20 percent) and depth (slack) of curtains shall be included

in designs to allow for tidal fluctuations and exchanges of water within the

curtain.



41

Special designs by the suppliers shall be provided for applications of curtains at

the required depths of 16 to 18 m or with currents exceeding 1.5 knots to ensure

that loads on curtains and mooring systems are not excessive and result in

failure of standard construction materials.

It should be noted that

o High winds can lift large curtains out of the water like a sail.

o Curtains can sink due to excessive biological or silt fouling on the fabric.

The number of joints in the curtain will be minimized – a minimum continuous

span of at least 15m shall be provided between joints.

Curtains will be a bright colour (yellow or International Orange) to enhance

visibility for vessels.

In tidal situations, where currents move in both directions, anchors will be

attached on both sides of the curtain to hold the curtain in place and to not allow

a curtain to overrun the anchors and pull them out when the tide reverses.

Anchor lines will be attached to the flotation devices.

Care will be taken during removal of silt curtains to avoid and minimize re‐

suspension of settled solids.

The sequence of installing sheet piling to secure the stability the Little Lagoon and the

central sandbank in the 205 extension area, prior to dredging, followed by dredging and

installation of the caissons, is shown in the following sequence of Figures.

Figure 2: Existing configuration at Berth 205 end of Pier 2, prior to Berth Deepening (Note sea water

is removed from the picture for the purposes of clarity



42

Figure 3: Dredge Basin and stabilise with scour protection as appropriate and construct sandbank

extension

Figure 4: Install new Caisson quay wall

4.3.2.3 Engineering Risk and Mitigation Summary

A Risk and Mitigation summary is provided below in regards to the Central Sandbank

Expansion. With mitigation all risks are reduced to ‘rare’ and ‘minor’ except for the fact that



43

high swells at sea will cause delays in the schedule. Although the impact with mitigation is

‘minor’, the likelihood remains ‘almost certain’.

Amended EIR - Proposed Deepening, Lengthening and Widening of Berth 203 to 205, Pier 2, DCT, Port of Durban (DEA Ref: 14/12/16/3/3/2/275)

44


45



46

4.3.2.4 Central Sandbank Morphological Study Summary

The study also provides a summary of the Central Sandbank morphological study.

A morphological acceleration factor has been applied to a 10 day simulation to effectively

illustrate the effect of erosion and sedimentation on the central sandbank, after a 50 year

period. This simulation has been performed for both scenarios, and has been repeated for

the Option 3H scenario with the effects of ocean waves omitted.

It has to be noted that the varying wind directions and velocities used for this 10 day period,

are typical for a spring season (actual recorded data for early October 2012 has been used).

Hence the accelerated results more closely represent what might be expected after a 50

year long spring season. The main purpose of these simulations is to compare pre‐ and

post‐construction scenarios and ascertain whether or not construction of the sandbank

extension resulted in significantly different erosion and deposition.

Figure 5: Pre‐Berth Deepening: Long term 50year ‐ Mean total transport



47

Figure 6: Option‐3H Post‐Berth Deepening: Long term 50year ‐ Mean total transport

Comparing for all scenarios, it may be seen that in each case, there are no discernable

differences in erosion and depositional trends for the sandbank or the Little Lagoon.

Sedimentation for the post construction scenario (Option 3H), appears to be marginally

higher in all cases, while total maximum erosion depths are very similar. This is attributable

to the larger sandbank providing increased surface area for erosion although the rate of

erosion may be equal.

4.3.2.5 Geotechnical Stability Analysis and Design Stable Slope Analysis

A geotechnical finite element analysis of the central sand bank has been undertaken using

the computer programme PLAXIS. Details of the analysis are provided in ZAA 1370‐RPT‐

041, Ref(10) in Annexure ‐2.

The analysis predicts that sandbank slopes of 1:4 will be stable, with an adequate factor of

safety. This has been confirmed by studying the existing central sandbank slopes, which

have a stable slope of 1:4.



48

Figure 7: Section A‐A (Central Sandbank Slope) Analysis



49

Figure 8: Section B‐B (Turning Basin Slope) Analysis



50

Figure 9: Section E‐E (Western Scour Protected Slope) Analysis

In conclusion, slope stability analysis using PLAXIS 2D 2012 has been carried out for the

new and existing sandbank slopes through all the construction phases during reclamation of

the central sandbank. Analysis has been conducted within the framework of Eurocode 7

Design Approach 1. All slopes have been designed to ensure adequate factor of safety

against failure. A double anchored sheet pile wall ensures stability of the existing sandbank

during installation of the caisson quay wall forming the western wall of the basin.

4.3.2.6 Geotechnical Field Study to Select Sand for Construction of the Sandbank

Extension

Geotechnical investigations have been completed by ZAA in the proposed dredged basin

area, as reported in ZAA 1370‐RPT‐031 Soil Material Reclamation for the Central Sandbank.

The objectives of the investigations were to determine the composition and distribution of the

soils and their basic engineering properties including their consistency. An estimation of the

different material type volumes was then undertaken.



51

The report presents the results of the investigations covering the entire area to be dredged,

but it also focuses on the properties, quantities and suitability of the soils in the dredge area

that could be used for construction of the sandbank extension.

The report makes use of extensive exploration, soils testing and expert evaluations from

earlier investigations in the dredge area, turning circle and central sandbank, in particular

those by the CSIR, Prestedge Retief Dresner Wijnberg Consulting Port and Coastal

Engineers (PRDW) and Hatch Mott MacDonald Goba JV (HMGJV).

The report is supplemented by ZAA 1370‐RPT‐004 Dredging Design and Survey report

which is relevant to the entire area to be deepened in the Durban Harbour during this

project.

4.4 Feasibility Study (FEL3) for the Deepening of Berths 203 to 205, Port of Durban –

Effects of Climate Change on Engineering Design (ZAA1370/RPT/028REVF) –

ZAA Engineering

4.4.1 Specialist

Specialist

Organisation: ZAA Engineering Projects and Naval Architecture (Pty) Ltd

Name: Dr John Zietsman

Qualifications: BSc (CivEng), UCT, MSc (Ocean Eng) University College London, PhD

University of London

No. of years experience: 39

Affiliations PrEng,

FSAICE,

MICE,

MRINA (overseas),

MSNAME,

FSAAE,

CEng

4.4.2 Main Findings

This section provides a summary of the effects of climate change on the engineering design.

The full report is contained in Appendix B3.

This report explains the basis of the approach that has been adopted in the Project Design

Premise to account for the effects of long term climate change on the marine engineering



52

design of the proposed Berth 203 to 205 Berth Deepening Project at Pier 2 in the Port of

Durban. The report was originally produced in response to a query raised by an Interested

and Affected Party (IAP) during a public meeting which was part of the Environmental Impact

Assessment (EIA) process. The EIA process and the application for an Environmental

Authorisation (EA) to authorise the project are vital components of the planning and

execution of this upgrade project.

The report further addresses the issues raised by the Department of Environmental Affairs in

its letter Ref 14/12/16/3/3/2/275 signed on 21 October 2013 issued in response to the initial

EIA Report.

The report does not purport to be a research paper on the subject of climate change and sea

level rise (SLR). The report reviews and summarises the available literature relating to

parameters affected by climate change that are relevant to the marine engineering design for

this project.

The parameters listed below are those that can be affected by climate change and are

relevant to the marine engineering design. These parameters have been taken into

consideration in the design of the proposed quays and associated dredging works:



Temperature


Currents

Waves

Rainfall

Ocean acidification

Various components of the design are affected by the above listed parameters. The report

summarises the impacts of the climate change affected parameters on the design of these

components. The various components affected are:

Selection of cope level for new quays - An important aspect of the design of a

quaywall is to establish a safe level for the top of the quaywall (the cope level).

This report explains how the design has more than adequately taken account of

sea level rise in terms of the reports published by recognised international

experts.

Structural design of new quay walls and quay furniture

Storm water management plan

Concrete design for durability



53

4.4.2.1 Sea Level Rise

Sea level has changed greatly over history and reached a level of about 120 meters below

current sea level at the Last Glacial Maximum 19,000-20,000 years ago. Last Glacial

Maximum refers to a period in the Earth's climate history when ice sheets were at their

maximum extension, between 26,500 and 19,000–20,000 years ago, marking the peak of

the last glacial period. During this time, vast ice sheets covered much of North America,

northern Europe and Asia.

Melting of the ice sheets during the Holocene Period, (generally accepted to have started

approximately 12,000 years BP (before present day), caused sea levels to rise, but climate

has been fairly stable over the Holocene and the graph (Figure 3.1.1.1) indicates minimal

change over the last 4,000 years.

There has been approximately 0.17m of sea level rise in the 20th century and an

accelerating trend is predicted in the 21st century.

Comparisons between Sea Level Rise for Southern Africa (based on approximately 30 years

of South African tide gauge records) and global tide gauge records, show substantial

agreement with global trends (Mather, 2008). Linear and nonlinear sea-level changes at

Durban, South Africa have been reported on by A.A. Mather, (Coastal and Catchment

Policy, Co-ordination and Management, eThekwini Municipality), in which the tide records

between 1970 and 2003 for Durban, South Africa, have been analysed to determine the

extent of recent linear and nonlinear sea level trends in the light of predicted global sea-level

rise. The linear trends of monthly mean sea level revealed a sea level rise of 2.7 mm ± 0.05

mm / year and the yearly mean sea-level trend revealed a rise of 2.4 mm ± 0.29 mm / year.

Nonlinear trends varied between –1 mm and +8 mm / yr. These findings are similar to

recently published results of global sea level rise calculations over the last ten years derived

from worldwide tide gauge and TOPEX / Poseidon altimeter measurements, which range

between 2.4 mm and 3.2 mm / year.

It can thus be concluded that the local South African rate of Sea Level Rise falls within the

range of global trends and for long-term design purposes the global sea level rise projections

(refer to section 2.2.3 below) are directly applicable to South Africa. It is noted that an

analysis of tide gauge records around South Africa (Mater et al, 2009) revealed a minor

variation in regional sea level trends (west coast vs. east coast) however these are

considered relatively minor in comparison to uncertainties in the long term global predictions.

The IPCC Climate Change 2013 predictions for Global Mean Sea Level Rise to the year

2100 ranges from 0.26m to 0.82m for the various Representative Concentration Pathways



54

(RCP) scenarios. For RCP8.5, the worst case scenario, a likely range of 0.45m to 0.82m is

predicted by 2100.

The upper bound predictions (both in terms of worst case scenario RCP and the upper

bound value within the RCP8.5 range), Climate Change 2013, Physical Science Basis,

Summary for Policy Makers, serves as the basis for design for this project. This is in

agreement with IPCC AR4 together with the scaled up ice sheet discharge, projected from

2095 to 2100.

The design life of the structures is until 2069 and using the 95% upper bound envelope, a

sea level rise value of 0.48m is predicted. Although the rate of change is expected to

increase over time, due to the uncertainties associated with the rate of increase and to be

conservative, we have assumed a linear increase between 1990 and 2100. Therefore a

value of 0.58m in 2069 has been conservatively adopted for the design criteria for the

project.

Figure 10: 1990 to 2100 sea level rise projections (after IPCC, 2001b; 2007b)2 with IPCC (2013)

Climate Change 2013, The Physical Science Basis, Summary for Policy Makers Ref (16) 0.82

metres at 2100

A sensitivity analysis has been undertaken investigating the probable water levels based on

climate change increases using 2100 increase predictions. Using a SLR of 0.79m and a



55

storm surge value of 0.828m (based on a 20% increase due to climate change), the

maximum water level predicted is +4.205m CDP.

The figure below shows the present situation, where the cope level is at +3.72m CDP. This

figure shows that the current level allows for the full tidal range, waves and storm surge, as

well as 443mm of freeboard.

Figure 11: Existing Quaywall

The figure below shows the new design with a cope level of +4.25mCDP with the tidal range,

waves and predicted storm surge after completion of construction in the year 2019. The

freeboard at that time relative to the latter parameters is 973mm.

Figure 12: Post Construction – Year 2019



56

The figure below shows how the new design with the cope level at +4.25m CDP deals with

the tidal range, waves, the predicted storm surge and sea level rise at the end of the design

life in the year 2069. At that time the freeboard will be approximately 324mm.

Figure 13: End of Structure Design Life – Year 2069

The figure below shows the situation in the year 2100, 31 years after the end of the design

life. The extreme water level at that time is due to sea level rise, tidal range, waves and

storm surge and the freeboard will be approximately 15mm.

Figure 14: Post Structure Design Life – Year 2100

At all times during construction of the new quays, which is estimated to take approximately 5

years, i.e. to about 2019, the old quays will remain in place and the new quays will be built in

front of them and to a level some 14% higher. The cope height of the existing quays at Pier 2



57

is at +3.72 m CDP. This has proved to be entirely adequate for storm, wave and tidal

conditions since their construction some 60 years ago and it is predicted that they will remain

adequate during the construction life of the project.

Where there are currently no existing quays or in some small areas where the top of the

existing quays will be demolished, Pier 2 and its inland structures will be protected by sheet

piles while the new quays are constructed. There is thus no vulnerability or risk of flooding

during the construction period.

4.4.2.2 Wind

There is generally low confidence in predictions of future wind speed changes. Several

model studies have suggested increased average and/or extreme wind speeds but some

studies point in the opposite direction. The changes in both average and extreme wind

speeds may be seasonally variable, but the details of this variation appear to be model-

dependent. IPCC predicts that future tropical cyclones will likely become more severe with

greater wind speeds.

In response to growing awareness of disasters that can result from climate change, the

International Atomic Energy Agency (IAEA), released a safety guide in 2003 detailing flood-

related hazards to nuclear power plants on coastal and river sites. The safety guide

suggests that newly constructed plants should account for an increase in wind strength of

between 5-10 percent over the 100 year life span of a nuclear plant due to the effect of

climate change. This recommendation appears to be based more on the dire consequence

of the failure of a nuclear plant rather than based on a statistical and proven model.

Nonetheless it is deemed prudent to make allowance for a possible increase in wind

strength.

The upper bound recommendations from the IAEA have been adopted for this project,

namely a 10% increase in wind strength over a 100 year life span. The design life of this

project is 50 years therefore a 5% increase in wind strength has been allowed for in this

project over and above the residual 1:50 year wind speed.

4.4.2.3 Storm Surge

Storm surge is an abnormal rise of water generated by a storm, over and above the

predicted astronomical tides. Storm surge is produced by water being pushed toward the

shore by the force of the winds moving cyclonically around the storm (wind set up) together

with the low barometric pressure associated with intense storms causing a rise in sea water

level. The US National Weather Service, who have records of extreme storm surge events,

state that the wind setup component is the primary component accounting for 95% of the



58

total storm surge with the low pressure component accounting for only 5% of the storm

surge.

Both the wind setup component and the low pressure component are a factor of the wind

speed. The wind setup is proportional to the square of the wind speed i.e. (wind speed)2,

whilst the low pressure component is directly proportional to the wind speed.

As stipulated in section 2.1 above, the design approach has been to first determine a current

residual value for storm surge based on a statistical analysis of historic data, and then

increase this value to account for climate change.

PRDW, 2003, analysed the tide records for the Port of Durban for the period 1972 to 2001

and compared these with astronomical tide predictions, the difference between the two

giving the storm surge value. A statistical analysis on these results revealed an increase in

tide level of 0.69m for a 1:100 year storm surge event. Although the project design life is 50

years, the 1:50 year event value is not available and we have therefore conservatively

adopted the 0.69m value as the residual value for storm surge.

To calculate the effect of climate change ZAA have used the 5% increase in wind speed as

explained in section 2.3.2 above and applied this percentage to the components affecting

storm surge.

Increase in storm surge = (1.05)2 * 0.95 (Wind setup) + 1.05 * 0.05 (Low pressure) = 1.1

Therefore a 10% increase is applied to the residual storm setup value.

i.e. Design criteria storm setup value = 0.69 x 1.1 = 0.759 m

4.4.2.4 Temperature

Future downscaled projections for changes in temperature are available for the Durban

region. According to the Durban 2010/2011 Municipal Climate Protection Programme report,

downscaled projections “suggest that an increase of 1.5-2.5 °C in mean annual temperature

by 2045-2065”. The projections are summary values produced by the University of KwaZulu-

Natal and presumably informed by the IPCC AR4 GCM data.

4.4.2.5 Rainfall

Short duration design rainfalls and their relative intensity (mm/hr) are relevant to the design

of the storm water management system for the project. The frequency of these storms is of

less relevance to the design of the storm water management system.

Limited information is available on the predicted increase in rainfall intensity in the Durban

area. Statistically downscaled data for precipitation is generally regarded as less reliable



59

than that for temperature. The Durban 2010/2011 Municipal Climate Protection Programme

report that “Rainfall is likely to increase slightly overall, but this rainfall will fall over shorter

time periods, which means that streamflows will be higher and faster”.

The recently released “Durban Climate Change Strategy - Water Theme Report: Draft for

Public Comment, January 2014” recommends increasing designs by 10% or even more as a

precaution against increased extreme events under future climatic conditions.

4.4.2.6 Ocean Acidification

Ocean acidification is the term given to the decrease in the pH of the Earth's oceans, caused

by the uptake of anthropogenic carbon dioxide (CO2) from the atmosphere. As CO2

dissolves into the oceans, rivers and lakes, some of it reacts with the water to form carbonic

acid. The potential impact of this acidification on the concrete quay wall has been examined.

4.4.2.7 Risk and Mitigation Summary

This report has reviewed and summarised available literature on parameters affected by

climate change that are relevant to the marine engineering design for this project. The IPCC,

(2013) Climate Change 2013, has been adopted as the primary reference for this report.

This is in agreement with IPCC AR4 (2007), together with the scaled up ice sheet discharge

allowance, projected from 2095 to 2100. This has been supplemented by guidelines

produced by UK Climate Projections Report June 2009 (UKCP09) and the National

Committee on Coastal and Ocean Engineering, Engineers Australia. A Bibliography is

contained in the Annexure.

This report clearly demonstrates that the chosen cope level of +4.25m CDP is sufficient,

providing a freeboard of 0.324m over and above the allowed for accumulation of various

upper bound increases for climate change affected parameters.

This indicates clearly that the risks and vulnerability of the new quays to climate change, and

in particular sea level rise and storm surge, have been minimised and that the selected cope

height of 4.25 m originally proposed by Transnet for this project is safe, conservative for its

design life of 50 years from the projected completion date of 2019 and that a safe freeboard

will still exist. In fact, given the year 2100 projection values, the structure is likely to be safe

for a further 32 years after 2069. In all cases this is in the event of the simultaneous

occurrence of all factors affecting the water level in the Port.



60

Various improbable extreme scenarios (e.g. UKCP09 H++) have been taken into account

when evaluating the design in terms of contingency planning in the event of these extreme

scenarios.

Other climate change affected parameters such as wind, rainfall and ocean acidification

have been taken account during the design of the quay structures, storm water system and

concrete specification.

The threat of flooding during the construction phase has been evaluated and we conclude

that construction will not adversely affect the current levels or increase the risk or

vulnerability to flooding.


61


62



63

5 SUMMARY OF RESPONSES PROVIDED

5.1 Central Sandbank

Table 4: Summary of Comments and Responses

Comment from DEA Response

What are the baseline

and thresholds of

acceptable change

against which

monitoring will take

place?

The approach to be adopted for assessing the rate of recovering of the

newly created portion of the Central bank and for determining when this

area can be considered to be fully recovered is known as the test for

bioequivalence and was developed by researchers in New Zealand -

McDonald & Erickson (1994). The approach is to define two areas to be

bioequivalent if the mean density of a particular organism or organisms at

suite of impacted sites (the newly created sandbank) exceeds a

predefined percentage (in this case 80%) of the mean density at a

reference or control sites (on the existing sandbank area) for a defined

time interval (in this case 2 years). Conversely, a site is said to be

impacted or disturbed until the selected variable(s) exceed(s) the

predefined level over a defined time interval. This procedure was

developed for testing the equivalence of drugs (Kirkwood 1981, Westlake

1988) but has since been adopted for other biological sciences as well

(Dixon & Garret 1992, McDonald & Erickson 1994). Full details of the test

are contained in McDonald & Erickson (1994).

The predefined percentage is necessarily site- or situation-specific, but the

value of 80% seems to have attained fairly wide acceptance (McDonald &

Erickson 1994, Underwood 1996). Similarly, the number of successive

intervals over which this value should be achieved is site- and situation-

specific but also depends on the sampling interval. Transnet is in the

process of establishing an ecological baseline for the central sandbanks

and will monitor recovery of the extension to these banks until such time

that recovery can be deemed complete in terms of the test for bio-

equivalence described above. The baseline assessment will be conducted

over a period of 12 months and will focus on the following components:

Physico-chemical (habitat) variables

Total Suspended Solids (TSS)

Salinity

Temperature

Dissolved Oxygen;



64


Sediment grain size distribution

Organic carbon content

Trace metal content in sediment (Cd, Hg As, Cr, Cu, Pb, Ni, Zn)

Faunal and floral assemblages

Benthic microalgae (microphytobenthos)

Benthic macrofauna

Fish

Birds

Baseline water quality characteristics will be established by taking water

quality measurements at a suite of 20 stations distributed in the navigation

channel adjacent to Berth 203-205 and in the main channel of the port

adjacent to the central sand bank. This will include a number of control

stations that will serve as reference stations in the future that will be

located outside of the influence of the proposed project activities (piling,

dredging, and sandbank construction). Daily water quality measurements

(salinity, temperature, dissolved oxygen and turbidity) will be taken at high

tide with a hand-held water quality meter (Hach HQ40d) at the surface and

bottom over a five day period each season (autumn, winter, spring,

summer) (total of 800 measurements over 12 months).

Baseline sediment characteristics will be established through collection of

sediment samples from 50 stations (10 supratidal, 20 intertidal and 20

subtidal) distributed on top and sides of the existing Centre bank in the

Port of Durban on four occasions (autumn, winter, spring, summer) over

the course of one year. Intertidal samples will be collected with a hand

corer (10 cm diameter) and subtidal samples collected with a Van Veen

grab. Samples will be placed in sampling jars on ice immediately after

collection and submitted to an SANAS accredited analytical laboratory for

determination of grain size distribution, organic and trace metal (Cd, Hg

As, Cr, Cu, Pb, Ni, Zn) content.

The baseline assessment for benthic microalgae biomass will be

undertaken through collection and analysis of sediment samples from the

same stations as for the sediment monitoring activities in accordance with

methods prescribed by Pinckney & Zingmark (1993). Sediment cores will

be taken by slowly inserting a plastic pipe of known diameter (≈20 mm),

either directly into the sediment (in the case of the intertidal samples) or

into the contents of the grab (in the case of the subtidal samples) down to

a depth of 40 mm. The top of the pipe will then be plugged with a bung

and a spatula inserted under the bottom of the tube, before it is slowly



65


withdrawn from the sediment. Samples will then be placed in sampling

jars on ice, protected from light, and submitted to an analytical laboratory

where microalgae biomass will be estimated as total chlorophyll (Chl a)

according to the methods of Whitney & Darley (1979), Dandonneau &

Neveux (2002) and Seuront & Leterme (2006).

The baseline assessment for benthic macrofauna characterisation will be

undertaken through collection and analysis of macrofauna samples from

the same stations as for the sediment monitoring activities. Samples will

be collected at four occasions over the year (autumn, winter, spring,

summer). Intertidal samples will be collected at spring low tide by inserting

a large (18 cm diameter) corer into the sediment to a depth of 30 cm,

plugging the open end, extracting the core and transferring the contents to

a 1 mm mesh bag. The mesh bag will be agitated until all the fine

sediment has been removed and the remaining contents placed in a

sample jar together with 5% formalin. Subtidal samples will be collected at

corresponding times (autumn, winter, spring, summer) using a Van Veen

grab deployed from a small inflatable boat. In all cases, macrofauna from

the samples will be extracted from the residual sediment in the lab,

identified to species level, counted and weighed (wet weight).

The baseline assessment of fish populations along the margins of the

centre bank will be undertaken using a 30 m beach seine net with 12 mm

stretched mesh. At least five hauls will be made on either side of the

centre bank on four occasions during the year (autumn, winter, spring,

summer). All fish and invertebrates collected in the net will be

enumerated, weighed and measured, and if possible, returned to the sea

alive.

The baseline assessment of birds utilising the centre bank will entail

counting all birds present on the Centre Bank once a month for 12 months

over spring-low tide periods. Numbers of birds of each species will be

recorded within a series of belt transects spanning the centre bank. These

belt transects will be oriented parallel to the shoreline of Centre Bank

along its southern and northern edges to form a series of blocks which will

extend from the waters’ edge up to the middle of Centre Bank. Counts will

be conducted with the aid of binoculars and telescope within a six hour

period.

Standard univariate and multivariate techniques will be used to describe

baseline characteristics for the benthic macrofauna, fish and bird

communities both in terms of abundance and biomass (fish and



66


macrofauna only). Univariate measurements will include total species,

species diversity, evenness and richness for intertidal and subtidal areas

and for each season and for the entire baseline period under assessment.

Multivariate analyses will employ techniques used in Plymouth Routines in

Multivariate Ecological Research (PRIMER) (Clarke and Warwick 2001),

specifically non-metric multidimensional scaling and cluster analyses, k-

dominance curves and an analysis of the characteristic and distinguishing

species (SIMPER) of macrofauna and fish at Centre Bank.

Once construction of the new sections of the central sandbank are

complete, monitoring of the recovery of this area will commence and will

be conducted in the same manner as for the baseline assessment. The

rate of recovery will be assessed in accordance with the test of

bioequivalence as described above. Monitoring will continue until such

time that the mean density of organisms in each of the above groups

(microalgae, macrofauna, fish, and birds) on the newly created sandbank

area is at least 80% of the mean density on the existing sandbank area,

averaged over a period of two years.

In addition to this, the following water quality parameters will be monitored

at a depth of 2 m at at least three stations along the southern edge of the

Centre Bank and at at least one station in Little Lagoon during the

construction (dredging) phase of the project:


Salinity

Temperature

Dissolved Oxygen

Data from the turbidity monitoring instruments will be available in real time

to the person coordinating dredging activities.

What actions are

proposed should the

monitoring results

detect change?

The following actions are proposed to mitigate impacts of dredging

(suspension of silt) on Durban Bay:

Installation of ‘Silt Curtains’ at the dredge burrow pit during

dredging to contain turbidity levels in the surrounding waters. The

lower end of the ‘skirt’ of the silt curtains will rest upon the

seafloor, and the top of the ‘skirt’ will be kept be above the water

surface.

The dredge hopper overflow will be choked with a fully-automated

computerized process controller that can ensure dynamic

adjustment of the valve in the overflow funnel which chokes the

flow in such a way that a constant fluid level in the hopper is



67


maintained and, as a result, no air is taken down with the

suspension leaving the hopper. This has been shown to

significantly decrease turbidity in the surrounding waters.

Minimise the time period over which the dredging operation is to

take place, to avoid the daily re-suspension of sediments.

If, in spite of these mitigation measures, turbidity levels exceed a threshold

level of 50 mg/l-1 at any of the monitoring stations referred to above,

during the dredge operations, the following actions will be implemented:

Dredging operations will be halted immediately and will not

recommence until levels have declined below threshold levels.

What are the socio-

economic and

ecological implications

should the proposed

mitigation measure

prove unsuccessful?

In the event that the proposed mitigation measures (construction of

additional sandbank area on the Central sandbank) prove unsuccessful,

the proposed development will result in the net loss of approximately 6%

of the existing intertidal area on the Centre Bank area or 3% of the total

existing intertidal-sand flat area in Durban Bay. However, it must be

recognised though that intertidal-sand-flat habitat in the Port of Durban has

already been reduced to only 14% of its original extent (Allan et al. 1999).

Thus, the remaining intertidal sand flat area is recognised as being

extremely important to the ecological functioning of the Port of Durban

(Newman et al. 2008; Weerts 2010). These banks are considered to be

very important for birds, juvenile fishes, and invertebrate populations in the

Bay and indeed the region as a whole (Day & Morgan 1956; Cyrus &

Forbes 1996; Forbes et al. 1996, McInnes et al. 2005, Weerts 2010). Any

further loss of this habitat type must be avoided or effectively mitigated.

It is not possible to quantify the precise ecological or socio-economic

implications of the loss of this habitat area should the mitigation measures

prove unsuccessful. The reason for this is two-fold. One the one hand it

can be argued that the newly created sandbanks may not as good as the

existing habitat area and thus will result in a proportional loss (up to a

maximum of 3%) in habitat for invertebrates, fish and birds populations in

the Bay as a whole. One the other hand it could be argued that any loss in

habitat area could result in a disproportionately large impact on populations

of affected species owing to the fact that this type of habitat (intertidal and

shallow subtidal sandbank) has been so severely reduced within the Port

of Durban already, that the affected species may be close to some sort of

tipping point which could result in a much larger reduction in their

population size. For example, McInnes et al. (2005) argue that “potentially



68


half the waterbird population of Durban Harbour could be negatively

impacted as a result of any modification of [the central sandbank].” This,

they argue, is because the intertidal sand banks play a critical role in

providing food in the form of invertebrates (macrofauna) to many bird

species.

It is the opinion of the marine specialists on the project team that the based

on evidence from previous attempts of this nature (both in the Port of

Durban and elsewhere) that the likelihood of successfully replacing habitat

lost through this development is good and hence ecological and socio-

economic costs are likely to be low or even negligible.

All the potential risks

and mitigation

measures associated

with the creation of the

Portion of Central

Sandbank as a

mitigation measure

must therefore be fully

assessed and be

addressed in the

amended report.

It is not possible to directly assess potential risks and mitigation measures

associated with the creation of the portion of the Central Sandbank without

relevant experimental evidence which is not feasible or even permissible in

this instance. However, it is possible to assess the potential risks and

mitigation measures indirectly through sophisticated computer simulation

modelling (as has been performed by both the CSIR and ZAA Engineering

projects and Naval Architects (Pty) Ltd as part of this EIA) and through

comparison with similar initiatives that have been undertaken elsewhere.

We were also able to collect a good deal of indirect evidence pertaining to

the likely success or failure of the mitigation measures proposed in this

study in respect of ecological recovery by reviewing available evidence in

the international literature. The results of this review suggest very strongly

that the likelihood of success is high and that faunal colonisation (by

macroinvertebrates at least) is likely to take place in a fairly short space of

time (months to years rather than decades). Summary information on

eight case studies from estuaries or shallow water marine systems are

presented below:

Evens et al. (1998) investigated the recolonisation of an existing

intertidal mudflat by macroinvertebrates and birds in the Tees

Estuary, England following restoration of tidal inundation. He

reported that a stable macroinvertebrate population had developed

after a period of 3 years. The actual success of restoring the

mudflats, however, could not be evaluated as no baseline data

were available prior to tidal inundation ceasing for comparative

purposes.

Ray (2000) reported on creation and colonisation of an artificial

mudflat made of dredge spoil on the coast of Maine, USA. In this



69


instance an artificial mudflat was created and its macroinvertebrate

community assessed and compared to an adjacent reference site

over a period of five years. The study found that diverse and

complex infaunal assemblages were able to establish themselves

on the mudflats constructed of dredged materials, and that within

three years the communities on constructed flats resembled those

on the natural flats.

Brooks (1983) reported on colonisation of dredged sediments on a

dredge spoil disposal site located at 20 m depth in Long Island

Sound. He found that three months after final capping of the

disposal site the numbers of benthic macrofauna individuals and

species present and were “roughly comparable” to those at the

reference stations and that after 15 months the number of

macrofauna individuals and species were significantly higher than

reference sites and in the predisposal reference collections.

Bolam & Whomersley (2005) reported on changes in physical

parameters and recovery of benthic macrofauna in dredge spoil at

three beneficial use schemes in estuaries in south-east England.

They found that environmental parameters (sediment redox

potential, and water, organic carbon and silt/clay contents) and

univariate community attributes (total individuals and species,

diversity, evenness and biomass) had attained reference levels at

two schemes but that assemblages differed significantly in terms of

species composition at all three schemes. (Note our concern

though with this approach articulated above)

Bolam et al. (2004) found that recolonisation of 1 m2 of defaunated

sediments resulted in recovery of univariate indices after only three

months and community structure after 6–12 months on a mudflat

in south-east England.

Beukema et al. (1999) reported that number of species and

individuals took 6 and 12 months to recover, respectively, following

the defaunation of larger areas (120 m2) of mudflat in the Dutch

Wadden Sea.

Vogt (2010) reported on experimental restoration of the Big Egg

Marsh in Jamaica Bay, New York City harbour. He reported on

recovery of salt marsh vegetation and macrofauna on artificial

islands constructed from dredge spoil. He found that the project

was a success in that the dredge spoil had been successfully



70


transforming into a silty and organic saltmarsh soil, that a dense

cover of smooth cordgrass had developed on the islands, and that

an “appropriate” animal community had become established.

Bolam and Whomersley (2004) found that the diversity, abundance

and species richness of two mudflat communities created from

dredged material near Jonesport, Maine, had re-established the

levels found at reference mudflats after two years.

Literature on the impacts and colonisation of offshore (deepwater) dredge

spoil disposal areas provides a similar perspective. Studies in the OSPAR

maritime area (North-East Atlantic) for example, indicate recovery rates for

species richness, abundance and diversity amongst macrofaunal

communities to range from 3 months to 2 years (Stronkhorst et al. 2003;

Bolam and Rees, 2003; CEFAS, 2005; Bolam et al. 2006a; b; Bolam &

Whomersley 2005; Van Dalfsen & Lewis 2006).

Risks and Mitigation Measures determined as part of ZAA Engineering

(2014a) are provided below:

High Turbidity and Total Suspended Solids (TSS) during dredging and

placement of sand bank extension

Mitigation:

Hydrodynamic and morphological analyses of dredging operation

have been carried out to determine whether the turbidity and TSS

concentration levels will be significant. The numerical model has

been set up using the Delft3D suite of tools to simulate the

interaction between the following processes: water level variation

due to tides, flow patterns within the port, wind and waves. The

approach adopted in the study has been to compare the

conditions at and near the seabed before, during and after

completion of the works, including : dredging in the harbour and

offshore; offshore disposal; construction of new quay structures

and scour protection.

Bed shear stresses and suspended solids concentrations have

been used to evaluate the hydrodynamic impacts during and after

completion of the works, compared with the present conditions.

The results of the study indicate that there will be no significant

negative impacts during or after completion of the works, either to

the main sandbank within the Port or to the beaches and coastline



71


outside the Port, compared to the status quo.

Special dredging equipment or procedures will be implemented to

reduce turbidity levels. It is anticipated that turbidity levels during

and after dredging and dumping will be less than the accepted

medium to low risk levels.

The turbidity and TSS are closely monitored during the dredging

process and dredging is temporarily suspended if turbidity and

TSS are close to the safe upper bound levels specified in the

Dredging Contract.

The dredge monitoring procedure used has been tested and

proven through use in the Cape Town berth deepening project in

the Ben Schoeman Dock.

Allowance has been made in the Dredging Contract Schedule to

cater for delays due to turbidity control.

The upper bound turbidity levels specified in the contract are

levels that are safe for all marine life.

Dredging operations cause sand bank to slip at the Berth 205 extension

end and the existing sandbank and the Little Lagoon area is damaged

Mitigation:

A sheetpile wall is designed and installed to international

standards.

Geotechnical and structural Finite Element analyses using PLAXIS

have been undertaken and these confirm that the design sheetpile

wall will provide the necessary stability to the existing Central

Sandbank.

Anchor pull‐out tests are being carried out to ensure that the

parameters assumed in the design of the sheet piling are safe and

realistic. The parameters being used are based on other recent

anchor pull‐out tests.

Scour protection has been designed to and will be installed in

compliance with international accepted standards.

Dredging operations cause sandbank extension to slip and the existing

Central Sandbank is damaged.

Mitigation:

The sandbank extension is designed with slopes not exceeding

existing stable slopes.



72


Geotechnical Finite Element analyses have been undertaken to

ensure that the slopes of the sandbank extension is stable.

The sand bank extension is constructed using the approved

Method Statement and is supervised to ensure that the extension

slopes will remain stable during construction. The method of

construction includes the use of baffle walls and berms to prevent

any slippage during construction.

If a local slip does occur it is repaired using normal maintenance

dredging.

The sandbank extension has been designed so that the existing

Central Sandbank will not in any way be affected by a slip of the

extension during or after construction.

High swell conditions at sea Delay in dredging schedule during

construction

Mitigation:

Allow for schedule delays in construction programme.

Obtain regular weather reports and plan accordingly.

Damage to Central Sand Bank extension due to Climate Change resulting

inter alia in changes in sea level and increase in frequency and severity of

storm surge. Extension is eroded more than existing sandbank would have

been and/or slips into dredged basin and large amounts of sand deposited

in dredged basins and channels

Mitigation:

Hydrodynamic and morphological analyses of anticipated severe

storms and variations in sea level have been carried out to

demonstrate that the stability of the sandbank extension will be at

least equal to that of the existing sandbank. The numerical model

has been set up using the Delft3D suite of tools to simulate the

interaction between inter alia the following processes: water level

variation due to changes in sea level caused by climate change,

storm surges and tides, flow patterns within the port, wind and

waves. Extreme wind velocities have been increased by a factor of

10% over current extreme levels.

If the sandbank is damaged, or a slip occurs, it is repaired during

maintenance dredging.

Extension has been designed so the existing Central Sandbank



73


cannot be damaged due to damage of the sandbank extension.

Damage to Central Sandbank extension due to inclement weather, wind,

waves, currents and storm surge. Extension slips into dredged basin and

large amounts of sand deposited in dredged basins and channels

Mitigation:

Perform numerical simulations to Dredge material out of the basin

and repair damaged area. Central Sand Bank

and Little Lagoon area protected by sheetpile wall during

construction and by caissons after construction.

Contract dredging procedures specify the limits of weather

conditions for dredging activities.

If a slip occurs it is repaired during maintenance dredging.


cannot be damaged by damage to the sandbank extension.

Consideration must be

given on how realistic

and practical the

mitigation measure is

and hat costly

commitment and

assurances have been

provided by the

applicant.

The risk assessment (above) shows that with mitigation nearly all risks are

reduced to ‘unlikely’ and ‘minor’. In addition the following should be noted:

Modelling of the Central Sandbank Extension stability shows that

comparing for all scenarios, it may be seen that in each case,

there are no discernable differences in erosion and depositional

trends for the sandbank or the Little Lagoon. Sedimentation for the

post construction scenario (Option 3H), appears to be marginally

higher in all cases, while total maximum erosion depths are very

similar. This is attributable to the larger sandbank providing

increased surface area for erosion although the rate of erosion

may be equal. A simulation omitting any wind and wave effects

reveals that close to zero erosion takes place over the sandbank.

A geotechnical finite element analysis of the central sand bank has

been undertaken using the computer programme PLAXIS. Details

of the analysis are provided in ZAA 1370‐RPT‐041. The analysis

predicts that sandbank slopes of 1:4 will be stable, with an

adequate factor of safety. This has been confirmed by studying the

existing central sandbank slopes, which have a stable slope of 1:4.

Hydrodynamic and morphological analyses of the Port of Durban

using DELFT‐3D to determine the short and long term stability and

form of the extended sandbank, including the effects of wave

penetration, wind and currents due to tidal movements and other

effects. These studies indicate that the extended sandbank will be



74


stable and that it will not endanger the stability of the existing

sandbank during construction, or during operation of the container

terminal. It also indicates that flows will not change in the area of

the Little Lagoon and this, combined with the sheet pile protection

to be installed, will ensure that the Little Lagoon is not disturbed.

Hydrodynamic analyses have been carried out to assess the levels

of turbidity and total suspended solids (TSS) that will result from

the dredging operations and the studies have confirmed that levels

will be within acceptable limits.

Geotechnical finite element analyses have been carried out using

the computer programme PLAXIS to ensure the stability of the

sandbank extension.

An extensive on site geotechnical investigation (involving Cone

Penetrometer Testing with pore water pressure data (CPTu) and

proof drilling and logging) has been carried out to determine the

nature and suitability of the sands that will be dredged from the

basin, for use in the construction of the sandbank extension.

Comprehensive dredging analysis and design has been carried

out.

Gaps, uncertainties and

assumptions must

clearly be reported.

Gaps and uncertainties have been provided in each specialist report.

Long Term Maintenance

burden must be

considered.

Modelling of the Central Sandbank Extension stability shows that

comparing for all scenarios, it may be seen that in each case, there are no

discernable differences in erosion and depositional trends for the sandbank

or the Little Lagoon. Sedimentation for the post construction scenario

(Option 3H), appears to be marginally higher in all cases, while total

maximum erosion depths are very similar. This is attributable to the larger

sandbank providing increased surface area for erosion although the rate of

erosion may be equal. A simulation omitting any wind and wave effects

reveals that close to zero erosion takes place over the sandbank. Based

on this there is no long term maintenance burden in regards to the Central

Sandbank (maintenance dredging as part of Port operations will be

required).



75

5.2 Climate Change Issues


Climate Change Risks

such as sea level rise

and storm surges must

be addressed.

The parameters listed below are those that can be affected by climate

change and are relevant to the marine engineering design. These

parameters have been taken into consideration in the design of the

proposed quays and associated dredging works:



Temperature


Currents

Waves

Rainfall

Ocean acidification

Various components of the design are affected by the above listed

parameters. The report summarises the impacts of the climate change

affected parameters on the design of these components. The various

components affected are:

Selection of cope level for new quays - An important aspect of

the design of a quaywall is to establish a safe level for the top

of the quaywall (the cope level). This report explains how the

design has more than adequately taken account of sea level

rise in terms of the reports published by recognised

international experts.

Structural design of new quay walls and quay furniture

Storm water management plan

Concrete design for durability

A Climate Change Risk

and Vulnerability

Assessment to

adequately address

how sea level rise and

coastal storm surges

will be addressed during

construction and

operational phase of the

proposed development.

Risk and vulnerability has been taken into account in the engineering

design. Please see Chapter 5.4 and Appendix B3 for more detail.



76

Comment from DEA –

22 April 2014

Response

Information regarding

climate risks, sea level

rise impacts and storm

surges must be

included in the report.

Information regarding climate risks including the following parameters

were included in the Effects of Climate Change on Engineering Design

Report:



Temperature


Currents

Waves

Rainfall

Ocean acidification

A summary of the report can be found in Chapter 5.4. The full study is

contained in Appendix B3.

Mitigation measures to

be provided.

Mitigation measures were summarised in Chapter 5.4. and are contained

in Appendix B3. In addition, Risks and Mitigation Measures determined as

part of ZAA Engineering (2014a) are provided below:

High Turbidity and Total Suspended Solids (TSS) during dredging and

placement of sand bank extension

Mitigation:

Hydrodynamic and morphological analyses of dredging operation

have been carried out to determine whether the turbidity and TSS

concentration levels will be significant. The numerical model has

been set up using the Delft3D suite of tools to simulate the

interaction between the following processes: water level variation

due to tides, flow patterns within the port, wind and waves. The

approach adopted in the study has been to compare the

conditions at and near the seabed before, during and after

completion of the works, including : dredging in the harbour and

offshore; offshore disposal; construction of new quay structures

and scour protection.

Bed shear stresses and suspended solids concentrations have

been used to evaluate the hydrodynamic impacts during and after

completion of the works, compared with the present conditions.

The results of the study indicate that there will be no significant

negative impacts during or after completion of the works, either to

the main sandbank within the Port or to the beaches and coastline



77

outside the Port, compared to the status quo.

Special dredging equipment or procedures will be implemented to

reduce turbidity levels. It is anticipated that turbidity levels during

and after dredging and dumping will be less than the accepted

medium to low risk levels.

The turbidity and TSS are closely monitored during the dredging

process and dredging is temporarily suspended if turbidity and

TSS are close to the safe upper bound levels specified in the

Dredging Contract.

The dredge monitoring procedure used has been tested and

proven through use in the Cape Town berth deepening project in

the Ben Schoeman Dock.

Allowance has been made in the Dredging Contract Schedule to

cater for delays due to turbidity control.

The upper bound turbidity levels specified in the contract are

levels that are safe for all marine life.

Dredging operations cause sand bank to slip at the Berth 205 extension

end and the existing sandbank and the Little Lagoon area is damaged

Mitigation:

A sheetpile wall is designed and installed to international

standards.

Geotechnical and structural Finite Element analyses using PLAXIS

have been undertaken and these confirm that the design sheetpile

wall will provide the necessary stability to the existing Central

Sandbank.

Anchor pull‐ out tests are being carried out to ensure that the

parameters assumed in the design of the sheet piling are safe and

realistic. The parameters being used are based on other recent

anchor pull‐ out tests.

Scour protection has been designed to and will be installed in

compliance with international accepted standards.

Dredging operations cause sandbank extension to slip and the existing

Central Sandbank is damaged.

Mitigation:

The sandbank extension is designed with slopes not exceeding

existing stable slopes.

Geotechnical Finite Element analyses have been undertaken to



78

ensure that the slopes of the sandbank extension is stable.

The sand bank extension is constructed using the approved

Method Statement and is supervised to ensure that the extension

slopes will remain stable during construction. The method of

construction includes the use of baffle walls and berms to prevent

any slippage during construction.

If a local slip does occur it is repaired using normal maintenance

dredging.

The sandbank extension has been designed so that the existing

Central Sandbank will not in any way be affected by a slip of the

extension during or after construction.

High swell conditions at sea Delay in dredging schedule during

construction

Mitigation:

Allow for schedule delays in construction programme.

Obtain regular weather reports and plan accordingly.

Damage to Central Sand Bank extension due to Climate Change resulting

inter alia in changes in sea level and increase in frequency and severity of

storm surge. Extension is eroded more than existing sandbank would have

been and/or slips into dredged basin and large amounts of sand deposited

in dredged basins and channels

Mitigation:

Hydrodynamic and morphological analyses of anticipated severe

storms and variations in sea level have been carried out to

demonstrate that the stability of the sandbank extension will be at

least equal to that of the existing sandbank. The numerical model

has been set up using the Delft3D suite of tools to simulate the

interaction between inter alia the following processes: water level

variation due to changes in sea level caused by climate change,

storm surges and tides, flow patterns within the port, wind and

waves. Extreme wind velocities have been increased by a factor of

10% over current extreme levels.

If the sandbank is damaged, or a slip occurs, it is repaired during

maintenance dredging.


cannot be damaged due to damage of the sandbank extension.



79

Damage to Central Sandbank extension due to inclement weather, wind,

waves, currents and storm surge. Extension slips into dredged basin and

large amounts of sand deposited in dredged basins and channels

Mitigation:

Perform numerical simulations to Dredge material out of the basin

and repair damaged area. Central Sand Bank

and Little Lagoon area protected by sheetpile wall during

construction and by caissons after construction.

Contract dredging procedures specify the limits of weather

conditions for dredging activities.

If a slip occurs it is repaired during maintenance dredging.

Extension has been designed so the existing Central Sandbank cannot be

damaged by damage to the sandbank extension.

5.3 Re-use of Dredge Material


22 April 2014

Response

Re-use of dredging

material is international

best practice. The

report should provide

examples and

references thereof.

The Ecological Risk Assessment found that in other parts of the world tidal

sand- and mudflat creation and restoration initiatives have been

undertaken with the expressed purpose of increasing this valuable habitat

type; e.g. USA (Levin et al. 1996, Ray, 2000), UK (Evans et al. 1998),

Japan (Lee et al. 1998; Ishii et al. 2008) and Australia (French et al. 2004).

In many cases this has involved the use of dredged materials. The

beneficial use of dredge spoil for use to create habitat is well established

and has been proved to successfully used invertebrates, fishes and bird

fauna. Indeed, the beneficial use of dredge spoil rather than disposal at

sea is widely regarded as best management practise for dredge spoil

disposal. This has long been realised and reported upon in the scientific

literature (Rhoads et al. 1978, Bolam and Whomersley 2003, 2005, Bolam

and Rees 2003, Yozzo et al. 2004).

Further, successful Habitat Creation/Restoration using dredged materials

has occurred in USA in the following locations:

Polar Island, Maryland



80

Lake Worth, Florida (Munyon Island, Peanut Island, Snook Island

and Johns Island)

Sonoma Baylands, San Fransico Bay, California

Deer Island, Mississippi

Craney Island, Virginia

Port Fourchan, Louisiana (Maritime Forest Ridge in Bayous

Cochon and Moreau and Baoyou DuPont Ridge)

Tennessee - Tennessee‐Tombigbee Waterway, Mississippi

Mobile Battleship Park, Alabama

Galveston Bay, Texas

Big Egg Marsh, New York Harbour

Jamaica Bay Marsh Islands, Brooklyn New York (Elders Point East

Marsh and Elders Point West Marsh)

Successful Brownfields Restoration has taken place at the following

locations in USA

Runyan Shipyard Penscola, Florida

New Jersey:

o Riverwinds Golf Course on Delaware Bay

o Prologis Port Reading Business Park

Flushing Airport, New York,Wetlands Brownfield Restoration

White Island, Brownfield Restoration

Fort Mifflin, Pennsylvania

Bark Camp Demonstration Project, Pennsylvania

Maple Beach area of Bristol Township, Bucks County, PA.

Dream Park, Logan Township, Gloucester County, New Jersey

A list of references is provided below.

1. Eurosion Case Study, Essex Estuaries (United Kingdom),

Colcester Borough Council, EUCC, 2003

2. Beneficially Using Dredged Materials to Create/Restore Habitat

and Restore Brownfields, and Team Collaborative Efforts that have

Achieved Success: Examples/Case Studies, Craig Vogt, May 2010

3. Development of Macrofaunal Communities on Dredged Material

Used for Mudflat Enhancement: a Comparison of Three Beneficial

Schemes after One Year, S.G. Bolam, P Whomersly, Marine

Pollution Bulletin, Elsivier, 2004

4. PIANC Working Group 1 1998: Management of Aquatic Disposal



81

of Dredged Material

5. PIANC Report No 104 – 2009 Dredged Material as a Resource

Consideration must be

given to the chemical

pollutants of the dredge

material.

Potential impacts associated with elevated suspended sediment

concentrations in the water column and toxicity of heavy metals,

hydrocarbons and polychlorinated biphenyls were also assessed. The

findings showed that the concentrations of metals and organic chemicals

in sediment within and near the dredge footprint were very low and thus

there was a very low probability that chemicals released during the

dredging process would be present in the water column at toxic levels.

More detail on the sediment quality within the dredge footprint was

provided in the final EIA report and was addressed by the CSIR (2012b).

However, as requested by the DEA letter – 22 April 2014, the chemical

pollutants of these sediments have been taken account in the Port as well

as at the Dredge Disposal Site. Mitigation measures at the Dredge

Disposal site are provided in the suite of EMPrs but are also summarised

in this report.

5.4 Alien Invasive Species


22 April 2014

Response

The revised report

should provide

examples and

references showing that

there are no risks

regarding the

establishment of alien

invasive species.

Colonisation by invasive alien species is not predicted to be a threat due to

the high salinities in the area as well as the fact that one of the main

invasive species required hard surfaces and thus will not colonise

sandbank habitat.

5.5 Stability of the Sandbanks


22 April 2014

Response

The stability of the

newly created sandbank

The Extension of the Sandbank – Engineering Risk Assessment report

took into account the findings of the Geotechnical finite element analyses



82

and cutaway were

exhausted tested and it

was found that the new

design would be more

stable than the current

layout.

have been carried out using the computer programme PLAXIS to ensure

the stability of the sandbank extension. The findings show that all slopes

have been designed to ensure adequate factor of safety against failure. A

double anchored sheet pile wall ensures stability of the existing sandbank

during installation of the caisson quay wall forming the western wall of the

basin.

A Morphological Study was also undertaken to determine the changes (if

any) of erosion and deposition at the Central Sandbank. Comparing for all

scenarios, it may be seen that in each case, there are no discernable

differences in erosion and depositional trends for the sandbank or the Little

Lagoon.

Sedimentation for the post construction scenario (Option 3H), appears to

be marginally higher in all cases, while total maximum erosion depths are

very similar. This is attributable to the larger sandbank providing increased

surface area for erosion although the rate of erosion may be equal.

Hydrodynamic and morphological analyses of the Port of Durban using

DELFT‐3D to determine the short and long term stability and form of the

extended sandbank, including the effects of wave penetration, wind and

currents due to tidal movements and other effects. These studies indicate

that the extended sandbank will be stable and that it will not endanger the

stability of the existing sandbank during construction, or during operation

of the container terminal. It also indicates that flows will not change in the

area of the Little Lagoon and this, combined with the sheet pile protection

to be installed, will ensure that the Little Lagoon is not disturbed.

5.6 Mitigation Measures and Monitoring


22 April 2014

Response

Quarterly or more

frequent monitoring

would be undertaken for

5 years

Baseline thresholds need to be established in order to confirm the defined

maximum/minimum water quality thresholds, to confirm the biotic

community composition on the existing sandbank and to allow

comparisons after the sandbank extension which show whether the

extension has been successful.

These thresholds will be determined from ecological baseline data that will



83

be collected over a period of 12-24 months prior to the start of the project.

The baseline assessments will focus on the following components:

Physico-chemical (habitat) variables:

Total Suspended Solids (TSS);

Salinity;

Temperature;

Dissolved Oxygen;

Sediment Grain Size Distribution;

Organic Carbon Content; and

Trace metal content in sediment (Cd, Hg, As, Cr, Cu, Pb, Ni,

Zn).

Faunal and floral assemblages:

Benthic microalgae (microphytobenthos);

Benthic macrofauna;

Ichythyfauna; and

Avifauna.

A graphic depicting how such a process may play out in the case of this

project is shown in Figure 18 below The blue and purple line represents

the average number of individuals or species at a suite of stations on the

existing sandbank distant from the impact (dredge) area (Control 1) and a

second group in close proximity to the area where the new sandbank

habitat will be created (Control 2), respectively. The red line represents

average abundance at a suite of stations on the newly created sandbank.

The dots on each line represent average values derived from discrete

samples collected at quarterly intervals (every 3 months) at these

respective sites. The horizontal dotted lines on the diagram represent

abundance for all the Control 1 stations (which are located far from the

impact site Control 1) average across the full time period of the study, and

the 80% level for these sites.

Sampling at the control stations will commence at 12-24 months before the

commencement date of the project and will continue until it can be

established that the biota at the control stations in close proximity to the

impact site (Control 2) and that on the newly established sandbank area

have recovered to a level that corresponds to at least 80% of the average



84

level measured at Control 1 (the lower dotted line).

Sampling at the stations on the newly established sandbank will

commence immediately after construction is complete (denoted by the

vertical dotted line on the left side of the diagram) and will continue until

the abundance at these sites exceeds the 80% level at Control 1 for at

least five years (denoted by the vertical dotted line in the centre of the

diagram). Note that in this diagram abundance at the control station in

close proximity to the impact site (Control 2) dropped during the

construction phase but recovered again shortly thereafter.

Figure 15. Graphic demonstration of procedures for monitoring

environmental impacts and recovery.

Minimized disturbance

on sandbanks during

construction including:

• No construction

workers allowed on

Sandbank;

• Dredging within

100m of the

Sandbank to be

undertaken during

winter;

• No dredging to be

done at night;

• Dredging within a

These mitigation measures are included in the suite of EMPrs. Mitigation

measures related to the Central Sandbank, Avifauna, Dredging and

Disposal etc. have also been included in this report.



85

100m should be

done as far as

possible at only site

at a time;

• A significant portion

of Central

Sandbank must

remain untouched

during dredging;

•

Qualified Environmental

Offices need to monitor

construction activities;

The EMPr makes provision for a qualified Environmental Control Officer

and an Environmental Officer for the Contractors. Roles and

responsibilities are summarised below:

A high-level outline of the institutional arrangements for the implementation

of the EMPs is provided in Figure 19.

Figure 16: Institutional Arrangements: Roles & Responsibility

Environmental Control Officer

The Environmental Control Officer (ECO) is a, competent (minimum of 3

years’ experience) and independent representative, who acts on as the

Environmental Monitoring Committee (EMC) monitoring representative for

the conducting of independent audits and performing a secretariat function

for the EMC.

The ECO will undertake bi-weekly inspections of the site and at least three-

monthly full compliance auditing against the EMP and Environmental

Authorisation. The aforementioned reports will be submitted to the Project

Manager, EMC and DEA for their records.

The ECO will also check the following:



86

The record of environmental incidents (spills, impacts, legal

transgressions, etc.) as well as corrective and preventive actions

taken;

The public complaints register in which all complaints are recorded, as

well as actions taken; and

Results from the environmental monitoring programme (turbidity,

sandbank expansion biodiversity monitoring, water quality; air quality

etc.).

Contractor’s Environmental Officer

The primary role of the competent Environmental Officer (minimum of 3

years’ experience) is to coordinate daily environmental management

activities of the Contractor on site.

Specific responsibilities of the Environmental Officer, who will be on site,

will include the following:

Aiding the Contractor to comply with all the project’s environmental

management requirements;

Assisting the Contractor in compiling Method Statements;

Facilitating environmental activities and environmental awareness

training of all persons on site;

Exercise an internal compliance management system on behalf of the

Contractor;

Inspect the site as required to ensure adherence to the management

actions of the EMP and the Method Statements;

Ensuring that environmental monitoring (air quality, water quality, etc.)

is being undertaken;

Complete Site Inspection Forms on a regular basis;

Provide inputs to the regular environment report to be prepared by the

ECO (as required);

Liaise with the construction team on issues related to implementation

of, and compliance with, the EMP;

Maintain a record of environmental incidents (spills, impacts, legal

transgressions etc) as well as corrective and preventive actions taken;

and

Maintain a public complaints register in which all complaints are

recorded, as well as action taken.

Reporting to the DEA The ECO will undertake bi-weekly inspections of the site and at least three-



87

must be frequent and

reporting of

disturbances must be

almost in a real time

basis

monthly full compliance auditing against the EMP and Environmental

Authorisation. The aforementioned reports will be submitted to the Project

Manager, EMC and DEA for their records.

The following sentence has been added to the EMPrs to ensure that the

DEA is aware of all disturbances:

The bi-weekly inspection must be submitted to the DEA within 7 days

of the inspection. Should any non-compliances be noted, they must

be submitted to the DEA within 24 hours of the incident.

If mitigation and

rehabilitation

measures fail then

offset measures

need to be discussed

As discussed at the meeting with DEA on 28 February 2014. Should the

extended monitoring (5 years from the day the construction of the

sandbank is extended) not find that abundance at the Extended Sandbank

reaches 80% of the average level measured at the control sites (on the

undisturbed area of the Sandbank), Transnet will enter into discussions

with the DEA regarding the potential for an offset. However, this measure

is not expected to be required for the following reasons:

Colonisation and succession of soft substrate benthic fauna has been well

studied in marine and estuarine systems, mostly in projects involving

dredging and dredge spoil disposal, but also in the context of in beach

nourishment and tidal flat habitat creation. Initial colonisation will be

dominated by opportunistic species. Based on the work of Pearson and

Rosenburg (1978) and Rhoads et al. (1978), Newell et al. (1998) proposed

a model of benthic recovery from disturbance (dredging) that involves

sharp increases in both number of species and abundance of organisms to

above that of baseline or control communities. This initial colonisation

comprises opportunistic species which generally reach a peak in

population numbers within six months. Models such as this are widely

accepted in the scientific literature, and are based on sound ecological

theory as well as empirical observations. Opportunistic species as initial

colonisers are, by virtue of the life histories and biology, either quick to take

advantage of new resources and/or exploiting resources in the absence of

competitors (Thistle 1981). Numerous experimental studies involving field

manipulation of sediments have shown very quick initial colonisation of

defaunated sediments. Botter-Carvalho et al. (2011) found colonisation to

occur very quickly with some species recruiting within one day, but others

obviously taking longer. Abundances at treatment sites were generally not

statistically different from those at control sites within six months. In



88

reviewing other studies of colonisation of defaunated sediments in the

subtropics they found abundance of macrofauna to recovery within periods

ranging from 2 weeks to 14 months, while species richness recovered

within 4 months to >19 months.

This concurs well with results from field studies of benthic colonisation and

succession after disturbance. Recovery rates of benthic communities in

these cases have been found to vary widely (Newell et al. 1998, Desprez

2000, Kotta et al. 2009, and references therein). Moreover, different

aspects of the community may recover at different rates. Desprez (2000)

cited several recolonisation studies where numbers of species and

abundance recovered quickly after dredging (within 12 months) but

biomass recovered at a slower rate. Similar findings were reported by

Newell et al. (2004). These studies were in temperate systems and in the

subtropical Durban Bay markedly slower biomass recovery is unlikely.

Other works have reported more rapid and complete recolonisation within

much shorter periods. Guerra-García et al. (2003) reported recovery within

about six months of dredging fine sediments in a small harbour while Van

Dolah et al. (1984) noted even quicker recovery (within three months) after

dredging soft estuarine muds.

While colonisation of defaunated sediments and recovery of total faunal

abundances and species richness can, and usually does occur rapidly,

recovery to a similar community as that at reference or undisturbed

sandbanks often takes longer. Published ranges of recovery periods

following dredge disposal in marine and estuarine systems vary but are

typically between nine months and four years (Bolam and Rees 2003).

Some studies have found shorter recovery of the benthic community (e.g.

six months, Guerra-García et al. 2003) while others have found much

longer recovery rates, although this is frequently related to long term

changes in habitat, such as changed sediment granulometry (e.g. Boyd et

al. 2005) or tidal elevation (e.g. Bolam and Whomersley 2003).

Summary information on a number of other case studies from estuaries or

shallow water marine systems is presented below:

Evens et al. (1998) investigated the recolonisation of an existing

intertidal mudflat by macroinvertebrates and birds in the Tees

Estuary, England, following restoration of tidal inundation. He

reported that a stable macroinvertebrate population had developed



89

after a period of 3 years. The actual success of restoring the

mudflats, however, could not be evaluated as no baseline data

were available prior to tidal inundation ceasing for comparative

purposes.

Ray (2000) reported on creation and colonisation of an artificial

mudflat made of dredge spoil on the coast of Maine, USA. In this

instance an artificial mudflat was created and its macroinvertebrate

community assessed and compared to an adjacent reference site

over a period of five years. The study found that diverse and

complex infaunal assemblages were able to establish themselves

on the mudflats constructed of dredged materials, and that within

three years the communities on constructed flats resembled those

on the natural flats.

Brooks (1983) reported on colonisation of dredged sediments on a

dredge spoil disposal site located at 20 m depth in Long Island

Sound. He found that three months after final capping of the

disposal site the numbers of benthic macrofauna individuals and

species present and were “roughly comparable” to those at the

reference stations and that after 15 months the number of

macrofauna individuals and species were significantly higher than

reference sites and in the predisposal reference collections.

Bolam and Whomersley (2005) reported on changes in physical

parameters and recovery of benthic macrofauna in dredge spoil at

three beneficial use schemes in estuaries in south-east England.

They found that environmental parameters (sediment redox

potential, and water, organic carbon and silt/clay contents) and

univariate community attributes (total individuals and species,

diversity, evenness and biomass) had attained reference levels at

two schemes but that assemblages differed significantly in terms of

species composition at all three schemes. (Note however, the role

of potentially confounding variables as articulated above).

Bolam et al. (2004) found that recolonisation of 1 m2 of defaunated

sediments resulted in recovery of univariate indices after only three

months and community structure after 6-12 months on a mudflat in

south-east England.

Beukema et al. (1999) reported that number of species and

individuals took 6 and 12 months to recover, respectively, following

the defaunation of larger areas (120 m2) of mudflat in the Dutch

Wadden Sea.



90

Vogt (2010) studied experimental restoration of the Big Egg Marsh

in Jamaica Bay, New York City harbour. He reported on recovery

of salt marsh vegetation and macrofauna on artificial islands

constructed from dredge spoil. He found that the project was a

success in that the dredge spoil had been successfully

transforming into a silty and organic saltmarsh soil, that a dense

cover of smooth cordgrass had developed on the islands, and that

an “appropriate” animal community had become established.

Bolam and Whomersley (2004) found that the diversity, abundance

and species richness of two mudflat communities created from

dredged material near Jonesport, Maine, had re-established the

levels found at reference mudflats after two years.

Literature on the impacts and colonisation of offshore (deep water) dredge

spoil disposal areas provides a similar perspective. Studies in the OSPAR

maritime area (North-East Atlantic) for example, indicate recovery rates for

species richness, abundance and diversity amongst macrofaunal

communities to range from 3 months to 2 years (Stronkhorst et al. 2003;

Bolam and Rees, 2003; CEFAS, 2005; Bolam et al. 2006a; b; Bolam and

Whomersley 2005; Van Dalfsen and Lewis 2006).

Silt levels in the water

column must be

maintained at

‘moderate’ levels and

silt screens must be

used while dredging

wherever possible

It is anticipated that during construction (dredging) phase of the project, the

primary impact vector will be levels of suspended sediment and/or organic

material in the water column. High levels of suspended sediment and

organic material can affect living organisms by reducing levels of dissolved

oxygen in the water column (mediated through the decomposition of

organic matter or release of hydrogen sulphide), by blocking the

transmission of light through the water column (thereby affecting

phytoplankton and macrolagal production), by blocking the gills or feeding

apparatus of filter feeding organisms (invertebrates, fish and sharks), or by

smothering benthic organisms. (Note that surveys of the dredge sediment

conducted as part of the EIA study (CSIR 2012a) have indicated that levels

of trace metals and other contaminants in the dredge sediments are low

and pose minimal risk to marine organisms). Thus, the focus during the

construction (dredging) phase of the project will be on ensuring that

suspended sediment levels in the water column adjacent to the sandbanks

do not exceed a defined threshold risk level of 50 mg/L and that oxygen

levels in the water column do not drop below 5 mg/L (99 % of the time) and

below 6 mg/L (95 % of the time).

These threshold risk level has been derived from the work of Steffani et al.

(2003) and from the South African Water Quality Guidelines (DWAF 1995).



91

Steffani et al. (2003) provided guidelines for concentrations of suspended

solids in relation to the risk they pose to benthic marine invertebrates,

which are considered to be amongst the most sensitive organisms to

elevated suspended sediment levels given that they are mostly sedentary

and are unable to move away from the source of impact, as follows:

Low risk: < 20 mg.L-1

Medium risk: 20-80 mg.L-1

High risk, requiring mitigation: > 80 mg.L-1

The defined threshold risk level of 50 mg/L lies at the centre of the

medium risk range as posed by Steffani et al. (2003).

The dissolved oxygen of water is a non-conservative property; solubility of

oxygen in water being dependent on the salinity and temperature of the

water (DWAF 1995). The South African Water Quality Guidelines provide

the following data on solubility of oxygen in seawater under constant

pressure (one atmosphere) for a range of salinities and temperatures

(Table 5). Cells spanning the typical range in temperature and salinity in

the Port of Durban and corresponding oxygen saturation values are

highlighted in grey on this table. From this it is clear that under ideal

conditions (i.e. 100% saturation), levels of dissolved oxygen would vary

between 6.3 and 8.2 mg/L under the influence of changing temperature

and salinity alone. For this reason the SA Water Quality Guidelines

recommend that the target levels for dissolved oxygen in the coastal zone

off the south and east coasts should not fall below 5 mg/L (99 % of the

time) and below 6 mg/L (95 %) of the time. These are also the defined

threshold risk levels that have been adopted for this study as well.

Table 5. Solubility of oxygen in seawater (mg/L) under

constant pressure (one atmosphere) for a range of salinities and

temperatures (Source: DWAFR 1995).

Temperature

Salinity

25x10-3

30x10-3

35x10-3

40x10-3

10 9,621 9,318 9,024 8,739

11 9,412 9,117 8,832 8,556

12 9,210 8,925 8,648 8,379

13 9,017 8,739 8,470 8,210

14 8,830 8,561 8,300 8,046

15 8,651 8,389 8,135 7,888

16 8,478 8,223 7,976 7,737



92

17 8,311 8,064 7,823 7,590

18 8.151 7,910 7,676 7,449

19 7,995 7,761 7,533 7,312

20 7,846 7,617 7,395 7,180

21 7,701 7,479 7,262 7,052

22 7,561 7,344 7,134 6,929

23 7,426 7,214 7,009 6,809

24 7,295 7,089 6,888 6,693

25 7,168 6,967 6,771 6,581

26 7,045 6,849 6,658 6,472

27 6,926 6,734 6,548 6,366

28 6,810 6,623 6,441 6,263

29 6,698 6,515 6,337 6,164

30 6,589 6,410 6,236 6,066

With this in mind the following protocol is proposed during the dredging

operations:

1. Continuous monitoring should be undertaken of turbidity and

dissolved oxygen levels at a point immediately adjacent to the

Central Sand Bank, between the bank and the dredger and/or

dredge hopper, and at a point immediately adjacent to Little

Lagoon at a point between the Lagoon and the dredger and/or

dredge hopper (hereinafter referred to as “the designated

monitoring stations”), during the dredge operations.

2. Data from such monitoring work should be available in real time to

the person coordinating dredging activities.

3. Dredging operations should be halted immediately if (a) turbidity

levels exceed a threshold level of 50 mg/L and/or (b) if levels of

dissolved oxygen are observed to drop below 5 mg/L for more than

1 minutes in every 60 minutes (1.7% of the time) or below 6 mg/L

for more than 3 minutes in every 60 minutes (5% of the time), and

should not recommence until levels have declined below this point.

4. If turbidity frequently exceeds or levels of dissolved oxygen

frequently drops below threshold levels at the designated

monitoring stations, ‘Silt Curtains’ should be deployed at the

burrow pit as a mitigation measure. The lower end of the ‘skirt’ of

the silt curtains must be allowed to rest upon the seafloor, and the

top of the ‘skirt’ must be above the water surface.

5. Turbidity should also be minimised by choking the dredge hopper



93

overflow with a fully automated system. In this scenario, a

computerized process controller ensures dynamic adjustment of

the valve in the overflow funnel which chokes the flow in such a

way that a constant fluid level in the hopper is maintained and, as

a result, no air is taken down with the suspension leaving the

hopper.

The little lagoon would

be specially protected

during construction and

afterwards

Continuous monitoring should be undertaken of turbidity and dissolved

oxygen levels at a point immediately adjacent to Little Lagoon at a point

between the Lagoon and the dredger and/or dredge hopper during the

dredge operations.

The purpose of this monitoring location is to ensure that there is no impact

on the Little Lagoon. Additional mitigation measures to protect the Little

Lagoon are included in the Suite of EMPrs. However the findings of the

specialists suggest that the main potential impact is related to increased

turbidity due to dredging.

The following additional mitigation measures are suggested to minimise

impacts related to turbidity:

1. Dredging operations should be halted immediately if (a) turbidity

levels exceed a threshold level of 50 mg/L and/or (b) if levels of

dissolved oxygen are observed to drop below 5 mg/L for more than

1 minutes in every 60 minutes (1.7% of the time) or below 6 mg/L

for more than 3 minutes in every 60 minutes (5% of the time), and


2. If turbidity frequently exceeds or levels of dissolved oxygen

frequently drops below threshold levels at the designated

monitoring stations, ‘Silt Curtains’ should be deployed at the

burrow pit as a mitigation measure. The lower end of the ‘skirt’ of

the silt curtains must be allowed to rest upon the seafloor, and the

top of the ‘skirt’ must be above the water surface.

3. Turbidity should also be minimised by choking the dredge hopper

overflow with a fully automated system. In this scenario, a

computerized process controller ensures dynamic adjustment of

the valve in the overflow funnel which chokes the flow in such a

way that a constant fluid level in the hopper is maintained and, as

a result, no air is taken down with the suspension leaving the

hopper.

Specific mitigation

procedures will need to

form part of the

Noted. During public consultation, Ulric Van Bloemestein from DEA:

Oceans and Coasts requested that certain best practices be included in

the Suite of EMPrs. These include the following:



94

Dumping at Sea

Permits. New best

practices measures and

standards gazetted in

2012 must be used in

the assessment of the

Dumping at Sea Permit.

A GPS record must be kept. This record must include:

o Time of departure from the dredge site

o Time of arrival at the disposal site

o Position of the vessel at the time of starting to discharge

dredge spoil.

o Heading and speed of the vessel at the time of starting to

discharge the dredge spoil.

o Position of the vessel at the time of completion of the

discharge of dredge spoil.

o Heading and speed of the vessel at the time of completion of

discharging of dredge spoil.

The daily track plot must be recorded electronically on a compact disc

in ASCII format.

This information must be provided to the ECO on a weekly basis.

The ECO must be notified immediately if there is an incident whereby

there is dumping of material outside the designated zone. The daily

track plot must also be provided immediately if there is an incident.

The hoppers must have load indicator equipment on board to ensure

that the hopper doors are not leaking and that no part of the load is

being deposited anywhere other than the designated disposal site.

Load Indicator data must be provided to the ECO on a weekly basis.

The load indicator graph shall be marked with the date and number of

each load.

Details of the load indicator equipment must be provided to the ECO

prior to commencement of operations.

The dredger must dispose dredge material in such a way that no large

mounds are produced.

The contractor must set up a matrix of the site to ensure there is even

dumping distribution and no disposal should occur at locations where a

sediment load has been deposited within the last week.

The dredger must dispose of sediment in as thin a layer as possible.

The volumes of disposal must be recorded and provided to the ECO

weekly. This will also be provided to the EMC on a monthly basis.

This mitigation measures will also be included in the submission for the

Dumping at Sea Permit. Measures and Standards gazetted in 2012 will

also be taken into account.

A monitoring

programme should

include sandbank

Noted. The following will be monitored as part of the baseline survey and

then during and after construction:



95

morphology, sediment

granulometry and

organic content, benthic

macrofauna, avifauna

and levels of pollutants.

Monitoring must be

undertaken intensely for

2 years and continue

less intensely for

another 3 years.



Salinity

Temperature

Dissolved Oxygen



Trace metal content in sediment (Cd, Hg As, Cr, Cu, Pb, Ni, Zn).



Benthic macrofauna

Fish

Birds

Adaption and mitigation

measures which may be

of importance to

infrastructure (in terms

of climate change) must

be addressed.

The Effect of Climate Change on Engineering design shows that the

chosen cope level of +4.25m CDP is sufficient, providing a freeboard of

0.324m over and above the allowed for accumulation of various upper

bound increases for climate change affected parameters.

This indicates clearly that the risks and vulnerability of the new quays to

climate change, and in particular sea level rise and storm surge, have been

minimised and that the selected cope height of 4.25 m originally proposed

by Transnet for this project is safe, conservative for its design life of 50

years from the projected completion date of 2019 and that a safe freeboard

will still exist. In fact, given the year 2100 projection values, the structure is

likely to be safe for a further 32 years after 2069. In all cases this is in the

event of the simultaneous occurrence of all factors affecting the water level

in the Port.

Various improbable extreme scenarios (e.g. UKCP09 H++) have been

taken into account when evaluating the design in terms of contingency

planning in the event of these extreme scenarios.

Other climate change affected parameters such as wind, rainfall and ocean

acidification have been taken account during the design of the quay

structures, storm water system and concrete specification.

The threat of flooding during the construction phase has been evaluated

and we conclude that construction will not adversely affect the current

levels or increase the risk or vulnerability to flooding.



96

6 SUMMARY OF ADDITIONAL MITIGATION MEASURES

Please note that these mitigation measures are an extension of the suite of EMPrs

presented in the Final EIA Report.

6.1 Central Sandbank

6.1.1 Management and Minimization of Habitat Loss

Minimise habitat loss of the Central Sandbank.

Ensure strict monitoring protocol is developed for Sandbank extension and recreated

seagrass beds.

Strict adherence to the Dredge Footprint Option 3H which involves the creation of a

Central Sandbank extension results in a slight increase in sandbank habitat.

Dredger track plots of dredging activity must be provided daily during the dredging of the

Dredge footprint and cross checked against the Dredge Footprint Option 3H by the

Contractor, EO and verified by the ECO.

The ECO should be onsite during the dredging of the Central Sandbank.

The contractor should produce a matrix for the Central Sandbank area to be dredged.

Photographs should be taken of each grid plot prior to dredging.

The contractor should produce a detailed method statement for dredging of the Central

Sandbank area.

A detailed pre-construction photographic record of dredging of the Central Sandbank

should be undertaken by the ECO.

Undertake a feasibility study for the additional mitigation measure of the creation of a

shallow subtidal area in the newly created Sandbank extension.

If feasible, submit separate EMP for the Establishment of Seagrass beds and attempt to

establish Zostera capensis (seagrass) beds.

The use of environmentally less damaging methods of scour protection should be

investigated (such as use of softer protection measures such as porous geotextiles or

meshes that allow recruitment of appropriate biota.

Long term stability of the Sandbank extension should be monitored.

o Bathymetric/topographical surveys should be undertaken one week after and

then one month after the completion of dredging. Thereafter, surveys should be

undertaken every six months.



97

Monitoring of ecological succession of the Sandbank extension is also essential. The

elements to be monitored include:

o Sandbank morphology (for bathymetric/topographical survey above);

o Sediment granulometry and organic content;

o Water physic-chemisty (in situ measurement including dissolved oxygen, turbidity

and chlorophyll levels;

o Benthic macrofauna and sandprawn densities;

o Ichthyofauna; and

o Avifauna.

As part of the seagrass bed creation, Zostera establishment, health and coverage should

be monitored (if feasible).

6.1.2 Management of Central Sandbank*

Ensure that the Central Sandbank incurs minimal indirect impacts associated with Berth

Infrastructure construction.

Stabilisation/retaining temporary sheet piles should be used for the Berth 205 extension

instead of the excavation of a stabilising slope.

The recommendations of the Storm Water Management Plan must be taken into

account.

During the construction phase of the extension of Berths 205 through to 203, cut‐off

drains are to be provided to collect stormwater in the affected areas which will be routed

temporarily and drained into adjacent stormwater system of the existing quay. This

stormwater system will apply to the sequence of three stages so that the existing

stormwater system at Berth 204 will accommodate the stormwater of the affected areas

of Berth 205. Likewise, the affected areas of Berth 204 will be accommodated by the

existing stormwater system of Berth 203.

The existing outlet pipes are to be blocked off separately during each construction stage

to ensure that the majority of the existing outlet pipes are operational at all times.

Sufficient additional temporary stormwater drain pipes will be provided to accommodate

extreme events.

Minimal changes to Durban Bay hydrodynamics through the choice of Dredge Footprint

Option 3H.

Use of Sheet Piles to stabilise the western edge of Berth 205 during excavation of the

Caisson trench which limits changes to port layout and related hydrodynamics.



98

Install scour protection to prevent future erosion, if required (and related further changes

to hydrodynamics of Durban Bay).

Conduct water quality monitoring at Central Sandbank and Little Lagoon.

All diffuse pollution sources to be managed to prevent pollution of the Estuary.

Storage area and ablution facilities to be located 100m from edge of the estuary.

No waste water to be released to the Estuary.

Ensure proper storage of material (including fuel, paint) that could cause water pollution.

Ensure proper storage and careful handling of hazardous substances with spill

prevention materials at hand.

Barges and dredging machinery to be maintained to prevent any oil and diesel pollution

during waterside construction activities.

Adequate environmental awareness to ensure construction labourers do not pollute

Durban Bay Estuary.

Spill management method statements for insitu concrete works (such as Soft Piling) to

be developed) to ensure adequate management of any spills.

o Ensure all water quality and pollution general mitigation measures are adhered

to.

o Ensure all mitigation measures contained in the Dredge Footprint and Disposal

EMP are adhered to.

o Ensure Sandbank Extension is undertaken prior to dredging of the western edge

of Central Sandbank adjacent to Berth 205 is removed.

o Ensure monitoring of the Sandbank Extension is undertaken as per the Pre-

Construction and Sandbank Extension EMP.

o Minimise disturbance to avifauna by ensuring noise minimisation measures are

implemented.

o Barricading and restricted access to be maintained to prevent unauthorised

access to Central Sandbanks during construction.

o Environmental awareness training to emphasise the importance of Central

Sandbanks.

o Zero tolerance policy regarding impacts to Central Sandbanks labourers.

6.1.3 Management of Central Sandbank Dredging

Minimise habitat loss of the Central Sandbank.

Ensure strict monitoring protocol is developed for Sandbank extension and recreated

seagrass beds.



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Ensure no long term erosion of the Central Sandbank occurs.

Strict adherence to the Dredge Footprint Option 3H which involves the creation of a

Central Sandbank extension results in a slight increase in sandbank habitat, and the

provision of a Caisson quay wall along the western edge of Berth 205 to ensure no long

term erosion.

Dredger track plots of dredging activity must be provided daily during the dredging of the

Dredge footprint and cross checked against the Dredge Footprint Option 3H by the

Contractor, EO and verified by the ECO.

The ECO should be onsite during the dredging of the Central Sandbank.

The contractor should produce a matrix for the Central Sandbank area to be dredged.

Photographs should be taken of each grid plot prior to dredging.

The contractor should produce a detailed method statement for dredging of the Central

Sandbank area.

Immediately prior to dredging of the Central Sandbank area, a walk down of each grid

square should be undertaken. Any biota which can be relocated to different areas within

the Central Sandbank should be moved. Details of relocated biota should be recorded

including information on location as well as a photographic record.

Environmental monitoring specialists should be on site during dredging of the Central

Sandbank area so to provide expert advice if required.

A detailed photographic record of dredging of the Central Sandbank should be

undertaken by the ECO.

Undertake the additional mitigation measures of the creation of a shallow subtidal area in

the newly created Sandbank extension and attempt to establish Zostera capensis

(seagrass) beds.

The use of environmentally less damaging methods of scour protection should be

investigated (such as use of softer protection measures such as porous geotextiles or

meshes that allow recruitment of appropriate biota.

Monitoring of ecological succession of the Sandbank extension is also essential. The

elements to be monitored include:

o Sandbank morphology (for bathymetric/topographical survey above);

o Sediment granulometry and organic content;

o Water physic-chemisty (in situ measurement including dissolved oxygen, turbidity

and chlorophyll levels;

o Benthic macrofauna and sandprawn densities;

o Ichthyofauna; and



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o Avifauna.

As part of the seagrass bed creation, Zostera establishment, health and coverage should

be monitored.

Long term stability of the Sandbank extension should be monitored.

o Bathymetric/topographical surveys should be undertaken one week after and

then one month after the completion of dredging. Thereafter, surveys should be

undertaken every six months.

o If any long term erosion does occur, the ECO, Project Manager, and EMC should

be notified immediately.

An emergency protocol should be development by specialists prior to dredging to ensure

there is an adequate mitigation programme to prevent further erosion, should any occur.

The slopes of the dredged area and scour protection placement must be done accurately

so to ensure immediate stabilisation of the area.

Temporary sheet piles should be used along the western edge of Berth 205 in order to

act as a retaining or stabilising wall during dredging.

6.1.4 Management of Central Sandbank Extension

Minimise disturbance to Central Sandbank area adjacent to Sandbank extension area.

Continuous monitoring should be undertaken of turbidity levels at a depth of 2 m at least

three stations along the southern edge of the Centre Bank and at least one station in

little lagoon during the Central Sandbank Extension. Data from the turbidity monitoring

instruments should be available in real time to the person coordinating dredging

activities.

Dredging operations should be halted immediately if turbidity levels exceed the proposed

threshold level of 50 mg/l-1 at any of the monitoring stations and should not recommence

until levels have declined below this point.

Pumping shall be controllable in rate so that it can be slowed if turbidity levels rise. It is

expected that pumping can be maximized over both high and low tide periods, but may

have to be reduced as tidal flows in both directions increase. In particular turbidity during

tidal flows away from the sandbank and towards the new basin must be strictly controlled

to prevent sand flowing back into the newly dredged areas.

Floating containment curtains extending well into the water will be required to restrict

movement of the more turbid water until it has settled.



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Pump the reclaim material behind the sandbag retaining structure in a sequence so that

the area is filled evenly and rises in layers from below. This procedure will reduce

entrainment of sand in the water column and thus reduce turbidity.

Ensure that all monitoring results are provided to the ECO and EMC and DEA as

required.

All monitoring is to be carried out by experts (trained marine biologists/ecologists).

6.1.5 Management of stabilization of the toe of the Extended Sandbank

Ensure Extended Sandbank is correctly stabilised.

Place sandbags along the line of the new toe of the extended sandbank to form a low

retaining structure.

Bio‐degradable sandbags would be preferred.

6.1.6 Offset Plan

As discussed at the meeting with DEA on 28 February 2014, should the extended monitoring

(5 years from the day the construction of the sandbank) not find that abundance at the

Extended Sandbank reaches 80% of the average level measured at the control sites (on the

undisturbed area of the Sandbank), Transnet will enter into discussions with the DEA

regarding the potential for an offset plan.

6.2 Avifauna

Ensure minimal disturbance to avifauna during construction.

Minimise Central Sandbank habitat loss.

Minimise impacts due to turbidity.

Infill dredged area of Centre Bank to meet adjacent to the quay wall of the west end of

Berth 205 and extend Centre Bank sand bank south as proposed in Option 3H of the

Dredging Layout (ZAA Engineering Projects & Naval Architects, 2012). This will result in

a net gain of intertidal sand flat.

Undertake all dredging within 100 m of the Centre Bank intertidal-sand flats during winter

when bird abundances are lower and Palearctic migrants are away (if possible).

When dredging within 100 m of Centre Bank intertidal-sand flats, do not dredge at

multiple sites concurrently, but only at one area at a time with a single dredger.



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No dredging operations should be conducted between sunset and sunrise within 100 m

of Centre Bank intertidal-sand flats including the infilling of sand up to the new quay wall

of Berth 205 and southward enlargement of Centre Bank.



little lagoon during dredging operations. Data from the turbidity monitoring instruments

should be available in real time to the person coordinating dredging activities. Dredging

operations should be halted immediately if turbidity levels exceed the proposed threshold

level of 50 mg/l at any of the monitoring stations and should not recommence until levels

have declined below this point.

If turbidity frequently exceed threshold levels at the monitoring stations adjacent o the

central sand bank and/or in little lagoon during dredging operations, use of ‘Silt Curtains’

at the burrow pit may be necessary. The lower end of the ‘skirt’ must be allowed to rest

upon the seafloor, and the top of the ‘skirt’ must be above the water surface.

Choking the dredge hopper overflow with a fully automated system is also

recommended. In this scenario, a computerized process controller ensures dynamic

adjustment of the valve in the overflow funnel which chokes the flow in such a way that a

constant fluid level in the hopper is maintained and, as a result, no air is taken down with

the suspension leaving the hopper. This results in a significant decrease in turbidity.

Minimise the time period over which the dredging operation is to take place, to avoid the

daily re-suspension of sediments.

6.3 Dredging and Dredge Disposal

6.3.1 Management of Dredger

Ensure only Trailer Suction Hopper Dredger (TSHD) or Cutter Suction Dredger (CSD)

are used.

Ensure TSHD or CSD are maintained in good order.

6.3.2 Management of Turbidity

Ensure that the Total Suspended Solids (TSS) standard which has been developed for

the Port of Durban is not exceeded (50mg/l)

Ensure that Total Suspended Solids (TSS) standard which has been developed for the

Offshore Sand Winning Site is not exceeded (20mg/l).



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little lagoon during dredging operations. Data from the turbidity monitoring instruments

should be available in real time to the person coordinating dredging activities.

Dredging operations should be halted immediately if turbidity levels exceed the proposed

threshold level of 50 mg/l at any of the monitoring stations and should not recommence

until levels have declined below this point.

If turbidity frequently exceed threshold levels at the monitoring stations adjacent to the

central sand bank and/or in little lagoon during dredging operations, use of ‘Silt Curtains’

may be necessary. The lower end of the ‘skirt’ must be allowed to rest upon the seafloor,

and the top of the ‘skirt’ must be above the water surface.

Choking the dredge hopper overflow with a fully automated system is also

recommended. In this scenario, a computerized process controller ensures dynamic



the suspension leaving the hopper. This results in a significant decrease in turbidity.

Turbidity levels at three stations around the Offshore Sand Winning site are to be

monitored continuously for at least two months prior to the start of the sand winning and

dredge spoil disposal operations and should continue for a minimum of two months after

all operations have ceased.

At no point should the turbidity levels exceed the established maximum threshold of 20

mg/L at the Offshore Sand Winning Monitoring Sites. All dredging/disposal operations to

cease until the turbidity levels have fallen below 20 mg/L.

The use of a Campbell Scientific TMS185 wireless turbidity monitoring station is

recommended and should be set to notify appointed personnel via text message should

turbidity levels exceed the maximum established threshold during dredging and disposal

operations .

All monitoring is to be carried out by experts (trained marine biologists/ecologists).

Minimise the time period over which the dredging operation is to take place, to avoid the

daily re-suspension of sediments.

All monitoring reports to be provided to ECO, EMC and DEA.

6.3.3 Management of Transportation of Dredge Spoil to Disposal site

Ensure detailed records regarding the transportation of dredge spoil are kept.

Ensure minimal leaking of dredge material outside disposal site.

Minimise likelihood of incidents where dumping of material outside disposal site occurs.



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A GPS record must be kept of the route followed by the hopper. This record must

include:


o Route followed by the vessel from dredge site to disposal site (GPS track)


o Position of the vessel at the time of starting to discharge dredge spoil.

o Heading and speed of the vessel at the time of starting to discharge the dredge

spoil.

o Position of the vessel at the time of completion of the discharge of dredge spoil.

o Heading and speed of the vessel at the time of completion of discharging of

dredge spoil.

o Route followed by the vessel on the way back to the dredge site (GPS track)

The daily track plot must be recorded electronically on a compact disc in ASCII format.


The ECO must be notified immediately if there is an incident whereby there is dumping

of material outside the designated zone. The daily track plot must also be provided

immediately if there is an incident.

The hoppers must have load indicator equipment on board to ensure that the hopper

doors are not leaking and that no part of the load is being deposited anywhere other than

the designated disposal site.

Load Indicator data must be provided to the ECO on a weekly basis. The load indicator

graph shall be marked with the date and number of each load.

Details of the load indicator equipment must be provided to the ECO prior to

commencement of operations.

6.3.4 Management of Disposal of Dredge Spoil at the Disposal Site

Ensure detailed records regarding disposal of dredge spoil are kept.

Ensure dredge material is only disposed within the permitted site.

Ensure only permitted volumes of dredge disposal are disposed.

Ensure dredge spoil is disposed of in a thin layer as practicable.

Ensure even distribution of dumping of dredge spoil.

Ensure minimal mortality of benthos at disposal site.

A GPS record must be kept. This record must include:



o Position of the vessel at the time of starting to discharge dredge spoil.



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o Heading and speed of the vessel at the time of starting to discharge the dredge

spoil.

o Position of the vessel at the time of completion of the discharge of dredge spoil.

o Heading and speed of the vessel at the time of completion of discharging of

dredge spoil.

The daily track plot must be recorded electronically on a compact disc in ASCII format.


The ECO must be notified immediately if there is an incident whereby there is dumping

of material outside the designated zone. The daily track plot must also be provided

immediately if there is an incident.

The hoppers must have load indicator equipment on board to ensure that the hopper

doors are not leaking and that no part of the load is being deposited anywhere other than

the designated disposal site.

Load Indicator data must be provided to the ECO on a weekly basis. The load indicator

graph shall be marked with the date and number of each load.

Details of the load indicator equipment must be provided to the ECO prior to

commencement of operations.

The dredger must dispose dredge material in such a way that no large mounds are

produced.

The contractor must set up a matrix of the site to ensure there is even dumping

distribution and no disposal should occur at locations where a sediment load has been

deposited within the last week.

The dredger must dispose of sediment in as thin a layer as possible.

The volumes of disposal must be recorded and provided to the ECO weekly. This will

also be provided to the EMC on a monthly basis.

6.3.5 Management of Ballast Water

Ensure compliance with TNPA’s Ballast water management plan.

A detailed method statement regarding Ballast Water management to be produced.

6.4 Climate Change

6.4.1 Climate Change Adaptation

At present, Transnet (and the TNPA) does not have a port wide approach or

methodology to assessing and incorporating climate change risks such as sea level rise

and coastal storm surge. Assessment of these issues is undertaken at an individual



106

project level, via Transnet’s project lifecycle planning process. The Effects of the

Climate Change on Engineering Design must therefore ensure that the effects of climate

change have been taken into account.

From a climate change adaptation perspective, the development options may be viewed

as more favourable than the “No Development” option as it will allow for climate change

adaptation criteria to be incorporated into the Berths 203 – 205 design parameters. The

present structures were designed at a time when climate change adaptation criteria were

not typically included in design parameters.

6.4.2 Climate Change Mitigation

The selection of development scenario (i.e. No Development, Partial Development or

Full Development) does not meaningfully impact on the GHG projections (either

cumulative total for 2012/13 – 2024/25 period or annual emissions by 2024/25).

Recommended GHG mitigation initiatives during the construction phase include:

o Requiring major contractors to report on their GHG emissions for the construction

phase.

o Requiring major contractors to provide a carbon mitigation plan, as part of the

construction planning activities, and as part of their overall environmental

management plan.

o Ensuring that the sources and quantities of major construction materials are

reported (i.e. steel and cement) to allow for tracking of GHG emissions associated

with these materials.

Key GHG mitigation initiatives targeting international maritime sector emissions include:

o Ensuring that the Berths 203 – 205 can readily accommodate the largest sized

container vessels possible (assuming that this is acceptable from a broader

environmental perspective).

o Adoption of an incentive programme to encourage the use of the most modern and

low carbon container vessels at Berths 203 - 205, such as the WPCI’s ESI

programme.

o Expanding TNPA’s GHG inventory to include reporting on international maritime

vessels docking at Berths 203 – 205.

o Implementing measures to address GHG emissions not captured in this

assessment i.e. cold ironing for vessels at Berths 203 – 205 (if not already

implemented).

Key GHG mitigation initiatives targeting land-based freight transport emissions include:



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o Massive expansion in the freight rail share of container transport flowing in and out

of Pier 2 (i.e. Berths 203 – 205), as compared to truck freight. The current share for

rail freight is estimated at 15% of TEUs. A minimum target of a 50% share should

be aimed for by 2024 and, ideally, closer to 85%.

o Continued investment in lower emission diesel electric locomotives operating the

container freight route to/from Pier 2 and a strategy of decarbonisation of the

electric traction network in relation to the freight rail servicing Pier 2.

o Implementation of GHG data gathering systems that allows for the generation of

freight rail corridor specific emission factors (i.e. kg CO2 per tonne-km or TEU-km

for specific freight rail corridors).

o Minimum standards and enforcement thereof for air emissions from freight trucks

handling cargo at Berths 203 – 205.

o Establishment of a Clean Truck Programme or similar incentive scheme aimed to

encourage replacement of older trucks with newer and lower GHG emitting

vehicles. This should not be implemented in a way that penalises marginal

operators (who cannot necessarily afford new vehicles), but could take the form of

a grant scheme, soft loan finance scheme or similar for qualifying truck freight

operators.

Damage to Central Sand Bank extension due to Climate Change resulting inter alia in

changes in sea level and increase in frequency and severity of storm surge. Extension is

eroded more than existing sandbank would have been and/or slips into dredged basin

and large amounts of sand deposited in dredged basins and channels

o Hydrodynamic and morphological analyses of anticipated severe storms and

variations in sea level have been carried out to demonstrate that the stability of the

sandbank extension will be at least equal to that of the existing sandbank. The

numerical model has been set up using the Delft3D suite of tools to simulate the

interaction between inter alia the following processes: water level variation due to

changes in sea level caused by climate change, storm surges and tides, flow

patterns within the port, wind and waves. Extreme wind velocities have been

increased by a factor of 10% over current extreme levels.

o If the sandbank is damaged, or a slip occurs, it is repaired during maintenance

dredging.

o Extension has been designed so the existing Central Sandbank cannot be

damaged due to damage of the sandbank extension.



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6.5 Little Lagoon

6.5.1 Management of Fencing and Restricted Access of Sensitive Environmental

Features

Ensure access to sensitive environmental features is restricted.

Ensure that access and fencing is maintained throughout the construction period.

Restrict access to Little Lagoon and ensure fences are maintained.

Ensure adequate signage of sensitive environmental features.

Maintain barricading/ fencing around sensitive environmental features.

Maintain adequate signage of sensitive environmental features.

Avoid any disturbance to demarcated sensitive environmental features.

Suitably experienced personnel to approve and monitor the fencing and restricted

access of sensitive environmental features.

6.5.2 Management of Little Lagoon

Ensure that the Little Lagoon is protected and incurs minimal negative impact to

resource quality.

Ensure nursery function of the Little Lagoon is not impacted.

Comply with the requirements of the National Environmental Management: Biodiversity

Act (No. 10 of 2004), National Forests Act (No. 84 of 1998), Natal Nature Conservation

Ordinance 15 of 1974 and Animal Protection Act (No. 71 of 1962).

Proper access control to be maintained to prevent access to Little Lagoon.

Stringent and dedicated control of poaching.

No fishing allowed.

Photographs of protected and sensitive fauna species must be displayed in the

construction camp to heighten awareness.

6.5.3 Management of Turbidity at the Little Lagoon

Continuous monitoring should be undertaken of turbidity and dissolved oxygen levels at

a point immediately adjacent to the Central Sand Bank, between the bank and the

dredger and/or dredge hopper, and at a point immediately adjacent to Little Lagoon at a

point between the Lagoon and the dredger and/or dredge hopper (hereinafter referred to

as “the designated monitoring stations”), during the dredge operations.



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Data from such monitoring work should be available in real time to the person

coordinating dredging activities.

Dredging operations should be halted immediately if (a) turbidity levels exceed a

threshold level of 50 mg/L and/or (b) if levels of dissolved oxygen are observed to drop

below 5 mg/L for more than 1 minutes in every 60 minutes (1.7% of the time) or below 6

mg/L for more than 3 minutes in every 60 minutes (5% of the time), and should not

recommence until levels have declined below this point.

If turbidity frequently exceeds or levels of dissolved oxygen frequently drops below

threshold levels at the designated monitoring stations, ‘Silt Curtains’ should be deployed

at the burrow pit as a mitigation measure. The lower end of the ‘skirt’ of the silt curtains

must be allowed to rest upon the seafloor, and the top of the ‘skirt’ must be above the

water surface.

Turbidity should also be minimised by choking the dredge hopper overflow with a fully

automated system. In this scenario, a computerized process controller ensures dynamic



the suspension leaving the hopper.

Monitoring will be the last measure. A clearly defined management action has been

identified if, in spite of control measures noted above, TSS levels during the dredge

operations exceed a threshold level of 50 mg.L-1 or dissolved oxygen levels drop below

5 mg/L (>1% of the time) or below 6 mg/L (>5%) at any of the monitoring stations,

Dredging operations will be halted immediately and will not recommence until levels

have declined below threshold levels.

6.6 Monitoring to Mitigate Impacts of Turbidity

The baseline thresholds of acceptable change for each of these aspects will be derived from

ecological baseline data that will be collected over a period of 12 months prior to the start of

the project, along with ongoing monitoring at control stations outside of the zone of impact

during and after the end of the construction period (sediment and biota only). The baseline

assessment will focus on the following components:



Salinity



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Temperature

Dissolved Oxygen



Trace metal content in sediment (Cd, Hg As, Cr, Cu, Pb, Ni, Zn).



Benthic macrofauna

Fish

Birds

Baseline water quality characteristics will be established by taking water quality

measurements at a suite of 20 stations distributed in the navigation channel adjacent to

Berth 203-205 and in the main channel of the port adjacent to the Central Sandbank. This

will include a number of control stations that will serve as reference stations in the future that

will be located outside of the influence of the proposed project activities (piling, dredging,

and sandbank construction). Daily water quality measurements (salinity, temperature,

dissolved oxygen and turbidity) will be taken at high tide with a hand-held water quality meter

(Hach HQ40d) at the surface and bottom over a five day period each season (autumn,

winter, spring, summer) (total of 800 measurements over 12 months).

Baseline sediment characteristics will be established through collection of sediment samples

from 50 stations (10 supratidal, 20 intertidal and 20 subtidal) distributed on top and sides of

the existing Central Sandbank in the Port of Durban on four occasions (autumn, winter,

spring, summer) over the course of one year. Intertidal samples will be collected with a hand

corer (10 cm diameter) and subtidal samples collected with a Van Veen grab. Samples will

be placed in sampling jars on ice immediately after collection and submitted to an SANAS

accredited analytical laboratory for determination of grain size distribution, organic and trace

metal (Cd, Hg As, Cr, Cu, Pb, Ni, Zn) content.

The baseline assessment for benthic microalgae biomass will be undertaken through

collection and analysis of sediment samples from the same stations as for the sediment

monitoring activities in accordance with methods prescribed by Pinckney and Zingmark

(1993). Sediment cores will be taken by slowly inserting a plastic pipe of known diameter



111

(≈20 mm), either directly into the sediment (in the case of the intertidal samples) or into the

contents of the grab (in the case of the subtidal samples) down to a depth of 40 mm. The

top of the pipe will then be plugged with a bung and a spatula inserted under the bottom of

the tube, before it is slowly withdrawn from the sediment. Samples will then be placed in

sampling jars on ice, protected from light, and submitted to an analytical laboratory where

microalgae biomass will be estimated as total chlorophyll (Chl a) according to the methods of

Whitney and Darley (1979), Dandonneau and Neveux (2002) and Seuront and Leterme

(2006).

The baseline assessment for benthic macrofauna characterisation will be undertaken

through collection and analysis of macrofauna samples from the same stations as for the

sediment monitoring activities. Samples will be collected at four occasions over the year

(autumn, winter, spring, summer). Intertidal samples will be collected at spring low tide by

inserting a large (18 cm diameter) corer into the sediment to a depth of 30 cm, plugging the

open end, extracting the core and transferring the contents to a 0.5 mm mesh bag. The

mesh bag will be agitated until all the fine sediment has been removed and the remaining

contents placed in a sample jar together with 5% formalin. Subtidal samples will be

collected at corresponding times (autumn, winter, spring, summer) using a Van Veen grab

deployed from a small inflatable boat. In all cases, macrofauna from the samples will be

extracted from the residual sediment in the lab, identified to species level, counted and

weighed (wet weight).

The baseline assessment of fish populations along the margins of the Central Sandbank will

be undertaken using a 30 m beach seine net with 12 mm stretched mesh. At least five hauls

will be made on either side of the Central Sandbank on four occasions during the year

(autumn, winter, spring, summer). All fish and invertebrates collected in the net will be

enumerated, weighed and measured, and if possible, returned to the sea alive.

The baseline assessment of birds utilising the Central Sandbank will entail counting all birds

present on the bank once a month for 12 months over spring-low tide periods. Numbers of

birds of each species will be recorded within a series of belt transects spanning the Central

Sandbank. These belt transects will be oriented parallel to the shoreline of the bank along

its southern and northern edges to form a series of blocks which will extend from the waters’

edge up to the middle of Central Sandbank. Counts will be conducted with the aid of

binoculars and telescope within a six hour period.



112

It is anticipated that during construction (dredging) phase of the project, the primary impact

vector will be levels of suspended sediment and/or organic material in the water column.

High levels of suspended sediment and organic material can affect living organisms by

reducing levels of dissolved oxygen in the water column (mediated through the

decomposition of organic matter or release of hydrogen sulphide), by blocking the

transmission of light through the water column (thereby affecting phytoplankton and

macrolagal production), by blocking the gills or feeding apparatus of filter feeding organisms

(invertebrates, fish and sharks), or by smothering benthic organisms. (Note that surveys of

the dredge sediment conducted as part of the EIA study (CSIR 2012a) have indicated that

levels of trace metals and other contaminants in the dredge sediments are low and pose

minimal risk to marine organisms). Thus, the focus during the construction (dredging) phase

of the project will be on ensuring that suspended sediment levels in the water column

adjacent to the sandbanks do not exceed a defined threshold risk level of 50 mg/L and that

oxygen levels in the water column do not drop below 5 mg/L (99 % of the time) and

below 6 mg/L (95 % of the time).

These threshold risk level has been derived from the work of Steffani et al. (2003) and from

the South African Water Quality Guidelines (DWAF 1995). Steffani et al. (2003) provided

guidelines for concentrations of suspended solids in relation to the risk they pose to benthic

marine invertebrates, which are considered to be amongst the most sensitive organisms to

elevated suspended sediment levels given that they are mostly sedentary and are unable to

move away from the source of impact, as follows:

Low risk: < 20 mg.L-1

Medium risk: 20-80 mg.L-1

High risk, requiring mitigation: > 80 mg.L-1

The defined threshold risk level of 50 mg/L lies at the centre of the medium risk range as

posed by Steffani et al. (2003).

The SA Water Quality Guidelines recommend that the target levels for dissolved oxygen in

the coastal zone off the south and east coasts should not fall below 5 mg/L (99 % of the

time) and below 6 mg/L (95 %) of the time. These are also the defined threshold risk

levels that have been adopted for this study as well.

With this in mind the following protocol is proposed during the dredging operations:



113

1. Continuous monitoring should be undertaken of turbidity and dissolved oxygen levels

at a point immediately adjacent to the Central Sand Bank, between the bank and the

dredger and/or dredge hopper, and at a point immediately adjacent to Little Lagoon

at a point between the Lagoon and the dredger and/or dredge hopper (hereinafter

referred to as “the designated monitoring stations”), during the dredge operations.

2. Data from such monitoring work should be available in real time to the person

coordinating dredging activities.

3. Dredging operations should be halted immediately if (a) turbidity levels exceed a

threshold level of 50 mg/L and/or (b) if levels of dissolved oxygen are observed to

drop below 5 mg/L for more than 1 minutes in every 60 minutes (1.7% of the time) or

below 6 mg/L for more than 3 minutes in every 60 minutes (5% of the time), and


4. If turbidity frequently exceeds or levels of dissolved oxygen frequently drops below

threshold levels at the designated monitoring stations, ‘Silt Curtains’ should be

deployed at the burrow pit as a mitigation measure. The lower end of the ‘skirt’ of the

silt curtains must be allowed to rest upon the seafloor, and the top of the ‘skirt’ must

be above the water surface.

5. Turbidity should also be minimised by choking the dredge hopper overflow with a

fully automated system. In this scenario, a computerized process controller ensures

dynamic adjustment of the valve in the overflow funnel which chokes the flow in such

a way that a constant fluid level in the hopper is maintained and, as a result, no air is

taken down with the suspension leaving the hopper.

Monitoring will be the last measure. A clearly defined management action has been

identified if, in spite of control measures noted above, TSS levels during the dredge

operations exceed a threshold level of 50 mg.L-1 or dissolved oxygen levels drop

below 5 mg/L (>1% of the time) or below 6 mg/L (>5%) at any of the monitoring

stations, Dredging operations will be halted immediately and will not recommence

until levels have declined below threshold levels.



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7 AMENDED EIA REPORT CONCLUSIONS AND

RECOMMENDATIONS

7.1 Best Practicable Environmental Option (BPEO)

Based on the recommendations of the additional specialist studies, no change to the BPEO

is suggested. A summary of the recommended BPEO is provided below:

The Caisson quay wall alternative was selected due to the following factors:

Poor soil conditions along the quay wall;

Safety considerations;

Low maintenance requirements;

No cathodic protection or specialist coating requirements;

Caissons built within the Port of Durban (at Lot 10) and can be floated into

position and thus no insitu casting of piles is required.

Dredge material from the dredge footprint can be used for the infill of the

Caissons and behind the quay wall at Berth 205 and thus reduces the volume of

dredge material to be disposed of; and

Environmental specialists did not have a preference in terms of quay wall

alternatives.

The Caisson quay wall will be used in combination with Dredge Footprint Option 3G. This

option was selected for the following reasons:

1. The provision of the Caisson quay wall along the western edge of Berth 205 prevents

long term erosion between the Little Lagoon and western edge of Berth 205.

2. The provision of the Central Sandbank Expansion results in a 0.03% net gain in

Central Sandbank habitat. This increases the area of shallow subtidal and interidal

habitats, which are ecologically important, by 49.7% and 4.1% respectively.

3. The use of dredge material in the creation of the Central Sandbank Expansion

decreases the volume to be disposed at the Offshore Disposal Site.



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Figure 17: Preferred Option Combination – Caisson Quay Wall with Option 3G Dredge Footprint.

Offshore Sand Winning will still be necessary. This will take place within Area 1 as

recommended by the Marine Biodiversity Specialist. Further, dredging will be contained

within a sub-area within Area 1 as suggested by the Maritime Archaeologist (Area 1a).



116

Figure 18: Area 1a (Preferred Sand Winning Area (Adapted from Maitland, 2012).

This option was selected for the following reasons:

2. Area 1 is more disturbed than Area 2 and the overall impact is likely be less significant

as this site has been used for dredge disposal in the past.

3. Although Area 1 has a known wreck, dredging will be contained to the northern strip

(Area 1a) as shown above and thus there is a lower probability of uncovering potential

Underwater Heritage Sites.

Further, as discussed in the Project Description (Chapter 9), Bayhead Lot 10 will be used at

the site camp, concrete batching area, temporary storage of fuel area etc.

7.2 Environmental Impact Statement

A study undertaken by Transnet (2009) showed that the existing blockwork quays of Berths

203 to 205, (designed in the 1970s), do not meet the required Eurocode 7 minimum

standards of safety and thus risk potential quay wall failure. This resulted in pre-feasibility

study being undertaken by PRDW (2011) which assessed seven possible quay wall

alternatives. These were assessed using a multi-criteria analysis and based on a number of

factors, three quay wall alternatives were selected for further analysis, namely, Caisson,

Sheet Pile and Deck on Pile. An assessment of alternative quay walls was then undertaken

by ZAA (2012). The Caisson option was highlighted as the most appropriate option due to

several factors including, the geotechnical conditions on site, improved safety and stability,



117

decreased maintenance requirements and no cathodic protection or specialised protective

coating requirements.

An Economic Impact Assessment was undertaken and found that if the expansion does not

occur significant loss of handling capacity of 284 108 TEUS carried on vessels too large to

be berthed if the depth at Berth 203 – 205 is not increased in the short term. This has a

direct spend loss impact of R1961m, induced spend of R1569m, port related employment

loss of 852 jobs and total employment loss of 3530 over the period of 2016 – 2020.

However, there was some concern regarding the impacts of the proposed project on Durban

Bay Estuary and the Central Sandbank. This led to a number of meetings including a

specialist integration meeting, where the environmental specialists and engineering project

team were provided with an opportunity to discuss the dredge footprint. The need to prevent

long term erosion and decrease habitat loss of the Central Sandbank resulted in a number of

dredge footprint alternatives. These were assessed by numerous studies including the

“Potential Long Term Impact on the Central Sandbank Study” (CSIR, 2012), the Estuarine

Biodiversity Study (Anchor Environmental, 2012a) and the Avifauna Impact Assessment

(Anchor Environmental, 2012c).

These discussions resulted in further discussions and modification of the dredge

alternatives. Further, ZAA (2012a) undertook new ship turning simulations and discussions

with the Port Harbour Master. Through a decrease in the berth channel width, a mitigation

measure of the Central Sandbank Expansion was added (Option 3D). This was further

modified and resulted in Option 3G. This option results in a 0.03% net gain in habitat and no

further expected long term erosion.

The Central Sandbank Study (CSIR, 2012a) found that some residual impact was expected

but that through the mitigation measures, the overall magnitude of this impact was low. The

Estuarine Biodiversity study and Avifauna Study (Anchor Environmental, 2012a and c) found

that habitat loss was the most significant impact. Through the addition of the Central

Sandbank Expansion, this impact was mitigated. In terms of open water habitat loss and soft

bottomed benthic habitat loss, the Estuarine Impact Assessment found that this impact was

not significant due to the disturbed nature of the dredge footprint (i.e. where maintenance

dredging has disturbed the soft-bottomed habitat). Further, the proposed infilling will not

change the tidal prism in such a way to effect water or sediment quality.

Modelling of turbidity was also undertaken by ZAA (2012b) in order to determine the impact

of dredging on turbidity within Durban Bay. The findings show that turbidity levels are

expected to be below medium to high risk levels. This impact was also verified by the

Estuarine Biodiversity Specialist. Sediment Analysis was undertaken by the CSIR (2012c) in

order to determine the quality of sediment within the dredge footprint. Heavy metal



118

concentrations were below warning levels and no toxic effects are expected. The findings of

this study suggest that the dredge material is safe for offshore disposal and should not pose

a significant threat to organisms at the disposal site.

The proposed project also includes the offshore sand winning for infill material. The offshore

sand winning study (Anchor Environmental, 2012b) found that Area 1 was previously

disturbed and was likely to re-colonise within 1-2 years. The impact on soft-bottomed benthic

fauna was not thought to be significant. Modelling of changes in bed shear stress (and

resultant possible erosion) of North and South Beach was also undertaken for Offshore

Disposal Site. Turbidity and changes in bathymetry will be greatest at the Offshore Disposal

Site and thus only this was modelled, however the results were used to add value to the

Offshore Sand Winning Study. No change in bed shear stress was noted (ZAA, 2012b).

Further, modelled turbidity for disposal (and thus for sand winning which results in less

sediment loading of the water) showed that turbidity was highest at the point of disposal but

dispersed quickly to levels which were below the medium to high risk levels.

Two Underwater Heritage Impact Assessments were undertaken, namely for the dredge

footprint within the Port of Durban and for the two potential sand winning sites (Area 1 and

Area 2). One known shipwreck (a 30 feet steel hull of a wreck called Stuart’s wreck) was

found in Area 1. Numerous magnetometer anomalies were found in both sites. These are

thought to be of low significance. The Maritime Archaeologist has suggested a portion of

Area 1 be made available for dredging of infill material. Within the Port of Durban, no

landside archaeological features will be impacted as the infrastructure on site is less than 60

years old. Some magnetic anomalies were noted within the Port but these could not be

verified. Based on this, the specialist has recommended that the dredging may take place as

long as certain mitigation measures are taken into account. These are provided in the suite

of EMPrs.

The Ecological Risk Assessment Report (CSIR and Anchor Environmental, 2014),

concluded that given the long term engineering stability of the proposed new sandbank

habitat, initial colonisation, succession and the establishment of an ecologically functioning

benthic community is certain. Further, given the proximity of this sandbank to the existing

Central Sandbank and its similarity in terms of structure, granulometry and hydrodynamic

characteristics, it is highly likely that a similar biological community will develop. Minor

differences should be expected and will probably beneficially increase benthic diversity in the

Bay. Successful establishment of benthic biota will result in profitable utilisation of the

created habitat by higher trophic level organisms (fish and birds). Fish especially will benefit

from the creation of additional shallow intertidal and subtidal habitat. These habitats are the

primary feeding areas for juvenile estuarine dependent species utilising Durban Bay as a



119

nursery. Shallow subtidal area is especially important. The present configuration and

bathymetry of Durban Bay, with a strong predominance of deep water habitat or intertidal

habitat, and limited shallow subtidal habitat, reduces its value as a fish nursery. Shallow

water offers juvenile fishes protection from predation by piscivorous fishes (Blaber 1987,

Ruiz et al. 1993). Such habitat is limited in Durban Bay at low tide, leaving juvenile fishes

susceptible to predation. The proposed sandbank extension results in significant increases

in these shallow water habitats and will fulfil an ecological role that is congruent with the

Bay’s ecological value as an estuarine embayment. Indeed in the long term it will improve

the systems ecological value.

However if after 5 years of monitoring it is found that abundance at the Extended Sandbank

does not reache 80% of the average level measured at the control sites, Transnet will enter

into discussions with the DEA regarding the potential for an offset plan.

The Extension of Sandbank Engineering Risk Assessment report (ZAA Engineering, 2014a)

summarised the work that has been carried out as part of the FEL‐3 study and has

addressed in particular the engineering issues, with respect to the extension of the central

sandbank, raised by the Department of Environmental Affairs in its letter Ref

14/12/16/3/3/2/275 signed on 21 October 2013 and issued in response to the initial EIA

Report, by means of the following:

A comprehensive Risk and Mitigation Analysis covering both the construction of the

extension and the maintenance of the sandbank during the operational phase of the

new container terminal at Pier


Hydrodynamic and morphological analyses of the Port of Durban using DELFT‐3D

to determine the short and long term stability and form of the extended sandbank,

including the effects of wave penetration, wind and currents due to tidal movements

and other effects. These studies indicate that the extended sandbank will be stable

and that it will not endanger the stability of the existing sandbank during

construction, or during operation of the container terminal. It also indicates that

flows will not change in the area of the Little Lagoon and this, combined with the

sheet pile protection to be installed, will ensure that the Little Lagoon is not

disturbed.

Hydrodynamic analyses have been carried out to assess the levels of turbidity and

total suspended solids (TSS) that will result from the dredging operations and the

studies have confirmed that levels will be within acceptable limits.





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An extensive on site geotechnical investigation (involving Cone Penetrometer

Testing with pore water pressure data (CPTu) and proof drilling and logging) has

been carried out to determine the nature and suitability of the sands that will be

dredged from the basin, for use in the construction of the sandbank extension.


This report showed that all risks were mitigated to a ‘’minor’ impact.

The Effects of Climate Change on Engineering Design Report (ZAA, 2014b) reviewed and

summarised available literature on parameters affected by climate change that are relevant

to the marine engineering design for this project. The IPCC, (2013) Climate Change 2013,

has been adopted as the primary reference for this report. This is in agreement with IPCC

AR4 (2007), together with the scaled up ice sheet discharge allowance, projected from 2095

to 2100. This has been supplemented by guidelines produced by UK Climate Projections

Report June 2009 (UKCP09) and the National Committee on Coastal and Ocean

Engineering, Engineers Australia..

The parameters listed below are those that can be affected by climate change and are

relevant to the marine engineering design. These parameters have been taken into

consideration in the design of the proposed quays and associated dredging works:



Temperature


Currents

Waves

Rainfall

Ocean acidification

The study demonstrates that the chosen cope level of +4.25m CDP is sufficient, providing a

freeboard of 0.324m over and above the allowed for accumulation of various upper bound

increases for climate change affected parameters.

The risks and vulnerability of the new quays to climate change, and in particular sea level

rise and storm surge, have been minimised and that the selected cope height of 4.25 m

originally proposed by Transnet for this project is safe, conservative for its design life of 50

years from the projected completion date of 2019 and that a safe freeboard will still exist. In

fact, given the year 2100 projection values, the structure is likely to be safe for a further 32

years after 2069. In all cases this is in the event of the simultaneous occurrence of all factors

affecting the water level in the Port.



121

Various improbable extreme scenarios (e.g. UKCP09 H++) have been taken into account

when evaluating the design in terms of contingency planning in the event of these extreme

scenarios.

Other climate change affected parameters such as wind, rainfall and ocean acidification

have been taken account during the design of the quay structures, storm water system and

concrete specification.

The threat of flooding during the construction phase has been evaluated and we conclude

that construction will not adversely affect the current levels or increase the risk or

vulnerability to flooding.

Based on the additional risk and vulnerability assessment studies undertaken to address

DEA’s comments, the Central Sandbank Extension is deemed a rational and acceptable

mitigation measure that has a high likelihood of success in terms of colonisation and

succession. In terms of engineering design, DELFT-3D models have shown that the

Sandbank Extension is stable and will require no long term maintenance. Mitigation

measures have been provided in this Annexure as well as the monitoring protocol required

to determine the baseline thresholds. The Sandbank Extension has a very low likelihood of

failure, however should this happen, the ecological implications would be similar to the

original Option 3C dredge footprint (5.6% loss of habitat and associated loss of functioning).

The biggest socio-economic impact of this loss would be related to recreational and

subsistence fishing (due to the loss of nursery habitat). However, it should be noted that the

Central Sandbank Extension will increase nursery habitat and thus will have a positive socio-

economic impact in this regard.

In regards to Climate Change, risk and vulnerabilities of the Port to changes in Climate have

been taken into account through the engineering design.

Thus, with the selection of the BPEO for the quay wall alternatives, dredge footprint and

offshore sand winning site, the adoption of the mitigation measures included in the Amended

EIA Report and original EIA report and the dedicated implementation of the suite of EMPrs, it

is believed that the significant environmental aspects and impact associated with this project

can be suitably mitigated. With the aforementioned in mind, it can be concluded that there

are no fatal flaws associated with the project and that authorisation can be issued, based on

the findings of the specialists and the impact assessment, through the compliance with the

identified environmental management provisions.



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7.3 Amended EIA Report Recommendations

The following key recommendations, which may also influence the conditions of the

Environmental Authorisation (where relevant), accompany the Amended EIA for the Berth

203 to 205 Expansion:

1. The mitigation measures contained in additional specialist studies must be taken into

account;

2. Baseline monitoring as described in CSIR and Anchor Environmental (2014) must be

undertaken;

3. The Sandbank Extension must be undertaken as set out in ZAA Engineering

(2014a);

4. Monitoring during the Sandbank Extension and Dredging must be undertaken as per

CSIR and Anchor Environmental (2014) requirements;

5. Transnet will enter into discussions with the DEA regarding the potential for an offset

plan if after 5 years the extended sandbank does not meet the required

abundance;and

6. All mitigation measures regarding climate change must be taken into account as per

ZAA Engineering (2014b).



123

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