i

KENYA PORTS AUTHORITY

REPUBLIC OF KENYA

ENVIRONMENTAL IMPACT ASSESSMENT REPORT

Consultancy for Proposed Dredging Works

at the Port of Mombasa

March 2009

Studied & Prepared by:

Consultants: Client:

HEZTECH ENGINEERING

SERVICES

CANNON TOWERS, 3RD

FLOOR,

MOMBASA

P.O BOX 42269 MOMBASA

JAPAN PORT CONSULTANTS

IN ASSOCIATION WITH BAC

ENGINEERING &

ARCHITECTURE.

P.O BOX 61231, NRB

KENYA PORTS AITHORITY

P.O BOX 95009

TEL: 2312211/2221211

MOMBASA

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ACCRONYMS

AIDS Acquired Immune Deficiency Syndrome

BAC BAC Engineering & Architecture Ltd

BOD Biological Oxygen Demand

COD Chemical Oxygen Demand

DRC Democratic Republic of Congo

EACC East African Coastal Currents

EAM East African Environmental Management Company Ltd

ECD Empty Container Deport

EIA Environmental Impact Assessment

EMCA Environmental Management and Coordination Act

GBHL Grain Bulk Handlers Limited

GDP Gross Domestic Product

GOK Government of Kenya

IMSR Inter Monsoon Short Rains

IMLR Inter Monsoon Long Rains

ITCZ Inter Tropical Convergence Zone

JBIC Japan Bank for International Cooperation

JPC Japan Port Consultants Ltd

KESCOM Kenya Sea Turtle Conservation Committee

KEFRI Kenya Forestry Research Institute

KARI Kenya Agricultural Research institute

KMA Kenya Maritime Authority

KMFRI Kenya Marine & Fisheries Research Institute

KWS Kenya Wildlife Service

KPA Kenya Ports Authority

NEC National Environmental Council

NEM North Eastern Monsoon

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NEMA National Environment Management Authority

NGOs Non Governmental Organisations

NMK National Museums of Kenya

NWCPC National Water Conservation & Pipeline Corporation

OSMAG Oil Spill Mutual Aid Group

OSRAT Oil Spill Response Action Team

RMG Rail Mounted Gantry

RTG Rubber Tyred Gantry

SEC South Equatorial Current

SLP Sea Level Pressure

SH Stakeholders

SSG Ship to Shore Gantry

TDS Total Dissolved Solids

TSS Total Suspended Solids

TOR Terms of Reference

TEU Twenty-foot Equivalent Unit

TGS Total Ground Slot

UNEP United Nations Environment Programme

WWF World Wildlife Fund

MARPOL International Convention for Prevention of Marine Pollution

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TABLE OF CONTENTS

ACCRONYMS ii

EXECUTIVE SUMMARY xiv

1.0 INTRODUCTION 1

1.1 Overview of the Project 1

1.2 Justification for the Project 2 1.2.1 Rapid increase in volume of containerized cargo 2 1.2.2 Competition from other ports 3 1.2.3 Worldwide trend towards use of the larger post-panamax ships 3

1.3 Present Environmental Conditions within Mombasa Port and its Environs 5 1.3.1 Water quality 5 1.3.2 Air quality 7 1.3.3 Sediment quality 8 1.3.4 Ecosystem 8

1.4 Terms of Reference for Environmental Impact Assessment 9

1.5 Consideration of Alternatives 13 1.5.1 Alternatives of sites for dumping of dredged material 13

1.5.1.1 Alternative A: Open water dumping 13 1.5.1.2 Alternative B: Land based dumping 14

1.5.2 The No Action alternative 15

2.0 BASELINE INFORMATION 16

2.1 Landscape, Topography and Geology 16

2.2 Climate 16

2.3 Hydrology 16

2.4 Soils 17

2.5 Population 19

2.6 Demographic Characteristics 19

2.7 Physical Infrastructure 20 2.7.1 Sea, road, rail and airport networks 20 2.7.2 Electricity supply 21 2.7.3 Water supply 22 2.7.4 Housing and sanitation 22

3.0 POLICY, INSTITUTIONAL AND LEGAL FRAMEWORK 23

3.1 Introduction 23

3.2 Legal Framework 23 3.2.1 The Environmental Management and Co-ordination Act, 1999 23 3.2.2 The Environment Impact (Assessment and Auditing) regulations, 2003 24 3.2.3 The Occupational Safety and Health Act, 2007 24

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3.2.4 The Water Act 2002 (No. 8 of 2002); Laws of Kenya 24 3.2.5 The Physical Planning Act; Laws of Kenya, Chapter 286 25 3.2.6 Local Government Act (Cap 265) 25 3.2.7 Kenya Ports Authority (KPA) Act 25 3.2.8 Kenya Maritime Authority Act 26

4.0 PROJECT DESCRIPTION 28

4.1 Introduction 28

4.2 Preliminary Survey 29 4.2.1 Hydraulic survey 29 4.2.2 Geotechnical Investigation 31 4.2.3 Sediment quality analysis 34 4.2.4 Conclusion on Preliminary Survey 34

4.3 Detailed Design 34 4.3.1 Capital dredging 35 4.3.2 Maintenance dredging 35 4.3.3 Ancillary works 35

4.4 Numerical Simulation 35 4.4.1 Ship operation simulation 35 4.4.2 Siltation simulation 36 4.4.3 Turbid water dispersion simulation 36 4.4.4 Wave penetration simulation 36

4.5 Quantity Calculation 36

4.6 Dredging Plan 38

4.7 Dredging Equipment 38 4.7.1 Dredging of turning and anchorage basins 38 4.7.2 Dredging of Access Channel and Navigation Channel at inner port 40 4.7.3 Maintenance dredging 41

5. THE PHYSICAL OCEANOGRAPHIC ENVIRONMENT AT KILINDINI HARBOUR 42

5.1 Introduction 42

5.2 Study area 43 5.2.1 Meteorological conditions 43 5.2.2 Coastal Currents 45

5.3 Data Collection and Analysis 46 5.3.1 Measurements of water elevation 46 5.3.2 Measurements of current velocities and temperature 46 5.3.3 Decomposition of tidal currents 46 5.3.4 Harmonic analysis 48 5.3.5 Spectral analysis 51

5.4 Results and Discussion 52 5.4.1 Tides 52 5.4.2 Currents 55 5.4.3 Temperatures 65

5.5 Numerical Modeling of Hydrodynamics of Kilindini Harbor 66 5.5.1 Additional Data Collection for Model Calibration and Validation 67 5.6.1 Turbidity Load Inputs 71 5.6.2 Dredging Period 71

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5.6.3 Interpretation of simulation results 71 5.6.4 The potential for sediment resuspension. 75 5.6.5 Hydrodynamic modeling of water quality impacts 77

5.7 Concluding Remarks 78 5.7.1 Hydrodynamic Characteristics 78 5.7.2 Numerical Modeling 79

6. THE BIOLOGICAL ENVIRONMENT 80

6.1 Introduction 80

6.2 Methodologies for Biological Studies 82 6.2.1 Scoping: 82 6.2.2 Fieldwork: 83

6.2.2.1 Water column assemblages 83 6.2.2.2 Sediment (benthic) assemblages 89 6.2.2.3 Critical habitats 90 6.2.2.4 Environmental data 92 6.2.2.5 MPA survey and analysis 93 6.2.2.6 Impact analysis, Mitigations and Monitoring plan 93

6.3 Baseline Characterizations 93 6.3.1 Water Column Assemblages – Planktons 93 6.3.2 Water Column Assemblages – Fisheries 95

6.3.2.1 Distribution of fishing effort 95 6.3.2.2 The ecological resources information 97 6.3.2.3 Fish production 98 6.3.2.4 Seasonality of the fishery by species 99 6.3.2.5 Economic value of the fishery 101 6.3.2.6 The potential and existing Aquaculture/ Mariculture 101

6.3.3 Sediment (benthic) assemblages 101 6.3.3.1 The soft sediments benthos 101 6.3.3.2 The epifaunal and infauna benthos 103 6.3.3.3 Hard substrata benthos and slow invertebrates 103

6.3.4 Critical Habitats: 104 6.3.4.1 Coral reefs and rocky platform communities (Andromache and Leven reefs) 104 6.3.4.2 Seagrass Beds 105 6.3.4.3 Seaweeds 106 6.3.4.4 Epiphytic seaweed community 106

6.3.5 Mangrove forest 107 6.3.6 Deep sea benthos 110 6.3.7 The Mombasa Marine Park and Reserve (MNPR). 110 6.3.8 Avifauna (Birds) 114 6.3.9 Marine turtles 116

7. WATER AND SEDIMENT QUALITY 119

7.1 Introduction 119

7.2 Methodology 119 7.2.1 Description of sampling area 119 7.2.2 Results and Discussion 120

7.2.2.1 Water quality 120 7.2.2.2 Sediment Quality 123

8. PUBLIC CONSULTATION AND PARTICIPATION 127

9. POTENTIAL IMPACTS AND MITIGATION MEASURES 128

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9.1 Impacts of Dredging 128 9.1.1 Loss of bottom habitat, shellfisheries, fisheries, fishery food sources 128 9.1.2 Water-column turbidity 128 9.1.3 Water contamination 128 9.1.4 Impacts on Port Operations 128

9.1.4.1 Discharge of garbage and litter 129 9.1.4.4 Sanitary wastes 129 9.1.4.5 Noise from Port traffic and Terminal operations 130

9.2 Oceanographic Environmental Impacts and Mitigation Measures 130 9.2.1 Oceanographic impacts of offshore disposal 130 9.2.2 Hydrodynamics 131 9.2.3 Waves 131 9.2.4 Predicted effect of the dredging project on water levels and tidal currents 132

9.3 Biological Impacts 134 9.3.2 Suspended sediment effects on sessile and slow-moving invertebrates 135 9.3.3 Suspended sediment effects on fish 135 9.3.4 Suspended sediment effects on ichthyoplanktic stages 136 9.3.5 Suspended sediment effects on phytoplankton productivity and other aquatic plants 136 9.3.6 Depletion of water column oxygen concentration 137 9.3.7 Noise during dredging / dumping activities 137 9.3.8 Sedimentation on subtidal muddy and sandy habitats 138 9.3.9 Oil spill effects on mangroves and seabirds due to coating 138 9.3.10 Oil spill affects on marine life and habitats 139 9.3.11 Other spills from containers and their effects on marine life 139 9.3.12 Spills from operational machinery and their affect on marine life 140 9.3.13 Ship wastes effect on marine life 140 9.3.14 Discharge of ballast water introduces alien species 140 9.3.15 Synergistic (cumulative) impacts 141

9.3.15 Potential negative impacts specific to coral gardens and Mombasa Marine Reserve 141

9.4 Chemical Impacts 142

10. ENVIRONMENTAL MANAGEMENT PLAN 143

10.1 Mitigation Measures 143 10.1.1 Mitigation measures for dredging impacts 143

10.1.1.1 Dredging work - General 143 10.1.1.3 Effluent discharge from calling ships 144 10.1.1.4 Accidental oil spill 144

10.1.2 Mitigation measures for biological impacts 145 10.1.2.1 Mitigation for fisheries impacts 145 10.1.1.2 Hindrance of Sea Turtle migration 146 10.1.1.3 Re-location of rare species before dredging if found 146 10.1.2.4 Monitoring of state of the environment of the key critical habitats 146 Suspended sediment effects on fish, sessile and slow-moving invertebrates 147 Suspended sediment effects on phytoplankton productivity and other aquatic plants 147 Depletion of water column oxygen concentration 147 Noise during dredging / dumping activities 147 Sedimentation on sub-tidal muddy and sandy habitats 147 Oil spill effects on mangroves and seabirds due to coating 147 Oil spill affects on marine life and habitats 147 Potential accidental spills from containers containing hazardous substances reach the sea and may affect marine organisms 147 Discharge of ballast water introduces alien species 147 Potential negative impacts specific to coral gardens and Mombasa Marine Reserve 147

10.1.3 Mitigation measures for chemical impacts 148

10.1.4 Mitigation measures for oceanographic impacts 148

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10.2 Monitoring Plan 149

10.3 Environmental Management Plan for the Construction Stage 151

10.4 Environmental Monitoring Survey 152

10.5 Contractors Pollution Control Measures 154

11. RECOMMENDATIONS AND CONCLUSION 155

REFERENCES 156

APPENDICES 162

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LIST OF FIGURES

Figure 1. 1: Locations and Dimensions of Dredging Works ..........................................................................2

Figure 1. 2 Container traffic at the Port of Mombasa between 1997 – 2004 ................................................3

Figure 1. 3: Spill of soda ash from Magadi Soda conveyor belt ...................................................................5

Figure 1. 4: Untreated effluent from Municipal treatment plant discharges to sea .......................................6

Figure 1. 5: A grab discharging clinker into a truck .......................................................................................7

Figure 1. 6: Alternative locations for proposed dumping sites ................................................................... 14

Figure 4. 1: : Location of the dredging and dumping areas ....................................................................... 28

Figure 4. 2.: Hydraulic survey .................................................................................................................... 30

Figure 4. 5: Area of Investigation ............................................................................................................... 32

Figure 4. 6: Results of seabed boring ........................................................................................................ 33

Figure 4. 7: Results of seabed material sampling ...................................................................................... 33

Figure 4. 8: Trailing Suction Hopper Dredger ............................................................................................ 39

Figure 4. 9: Grab Dredger .......................................................................................................................... 40

Figure 5.1: Seasonal variations of the average wind speed during the northeast and southeast monsoons

................................................................................................................................................................... 44

Figure 5.2: KMFRI GLOSS Tide Gauge at Liwatoni jetty in Kilindini harbour, Mombasa .......................... 48

Figure 5.3: Time series water level variations at Mombasa tide gauge station for year 2007, observed

(blue), computed (red) and residual (magenta) values from harmonic analysis. ....................................... 55

Figure 5.4: Time series of current velocities at Liwatoni station ................................................................ 57

Figure 5.5: Time series of (a) observed (b) computed and (c) residual for u-velocity components at

Liwatoni station from harmonic analysis results......................................................................................... 58

Figure 5.6: Time series of (a) observed (b) computed) and (c) residual for v-velocity components at

Liwatoni station from harmonic analysis results......................................................................................... 59

Figure 5.7: Observed current directions versus speeds at Liwatoni station .............................................. 60

Figure 5.8: Scatter plot of north-south (u) and east-west (v) current velocity components ....................... 61

Figure 5.9: Comparison of water levels (solid line) and current velocities (doted line) at Liwatoni station

during spring tide. ....................................................................................................................................... 62

Figure 5.10: Relative energy density spectrum for water levels Liwatoni station based on spectral

analysis. ..................................................................................................................................................... 63

Figure 5.11 Relative energy density spectrum for current velocities at Liwatoni station based on spectral

analysis. ..................................................................................................................................................... 64

Figure 5.12: Time series of water temperatures at Liwatoni station .......................................................... 65

Figure 5.13: Comparison of water levels and temperatures at Liwatoni on (a) December 15, 2007 from

midnight and (b) December 20, 2007 from midnight ................................................................................. 66

Figure 5.14: Stations at Kilindini harbor for monitoring tides, currents and suspended sediment

concentrations as well as salinity in February to March 2008 ................................................................... 67

Figure 5.15: Result of two-dimensional bathymetric survey of Kilindini harbour ....................................... 70

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Figure 5.16: Turbid water dispersion simulation (surface and bottom layers) at offshore dumping during

NE Monsoon season (Jan – Apr). .............................................................................................................. 72

Figure 5.17: Turbid water dispersion simulation (surface and bottom layers) at offshore dumping during

SE Monsoon season (Jul – Oct). ............................................................................................................... 73

Figure 5.18: Turbidity water dispersion due to dredging works at Turning Basin and temporary dumping at

New Container Terminal during NE Monsoon. .......................................................................................... 74

Figure 5.19: Turbidity water dispersion due to dredging works at Turning Basin and temporary dumping at

New Container Terminal during SE Monsoon. ........................................................................................... 75

Figure 5.20: Results of numerical simulations of siltation before and after dredging during the South East

Monsoon season and the siltation difference before and after dredging. .................................................. 76

Figure 5.21: Results of numerical simulations of siltation before and after dredging during the North East

Monsoon season and the siltation difference before and after dredging. .................................................. 77

Figure 6.1 Coastal type, biological resource, and human use features of the port entrance area, Kilindini

harbour and Tudor Creek (after Environmental Sensitivity Map, KenSea; Tychsen 2006) ....................... 82

Figure 6.2: Coastal type, biological resource, and human use features at the western end of Port Reitz

Creek (after Environmental Sensitivity Map, KenSea; Tychsen 2006) ...................................................... 82

Figure 6.5: Landsat image (bands arrangement 3-2-1) showing the port entrance and the study sites

studied for coral cover ................................................................................................................................ 91

Figure 6.6: Proportions of major phytoplankton groups in the samples analyzed. See appendix- for details

on specific categories ................................................................................................................................. 94

Figure 6. 7: Occurrence of zooplankton taxa in water samples from Port Reitz ....................................... 95

Figure 6.8: No of foot fishers and boats per landing sites Likoni ............................................................... 96

Figure 6.9: No of boats and fishers per landing sites / Changamwe ........................................................ 96

Figure 6.10: Fish landings (kg) at Likoni landing sites for five years ......................................................... 98

Figure 6.11: Seasonality in landings of pelagic fish species in Port Reitz creek ....................................... 99

Figure 6. 12: Seasonality of landings of key demersal fish species in Port Reitz creek .......................... 100

Figure 6.13: Seasonality of landings of sharks and crustacea in Port Reitz creek .................................. 100

Figure 6.14: Seasonality in landings of octopus, squids, crustacean Likoni ............................................ 101

Figure 6.15: Macrobenthos from Port Reitz ............................................................................................. 102

Figure 6.16: Macrobenthos from Shelly Beach ........................................................................................ 102

Figure 6.17: Occurrence of common taxa in benthic samples from Globallast survey (Source - KMFRI

2006) ........................................................................................................................................................ 103

Figure 6.18: Map of the Kenya coast highlighting KESCOM study sites which included Shelly and Nyali

beach (near the entrance to the port). South Coast (SC), Mombasa (MSA), Kilifi (KFI), Watamu (WTM),

Malindi (MAL), Kipini (KIP) Lamu (LAM), and Kiunga (KIU). (Source: Marine Turtle Newsletter 105:1-6, ©

2004). ....................................................................................................................................................... 117

Figure 9.1: Results of wave penetration simulation showing that change of wave heights

(increase/decrease) due to dredging is negligible (less than 10%). ........................................................ 132

Figure 9. 2: Numerical simulation results of created current velocities vector field in Kilindini harbour

including the offshore dumping site and the adjacent Tudor creek ......................................................... 133

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Figure 10.2: Monitoring scheme .............................................................................................................. 149

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LIST OF TABLES

Table 2. 1. Population distribution in the Mombasa District ....................................................................... 19

Table 4. 1 Item and Purpose of Hydraulic Survey 29

Table 4. 2: Key Survey Results .................................................................................................................. 30

Table 4. 3: Item and Purpose of Geotechnical Investigation ..................................................................... 31

Table 4. 4: Primary Investigation Results .................................................................................................. 32

Table 4. 5: Item and Purpose of Sediment Quality Analysis ...................................................................... 34

Table 4. 6: Capital Dredging ...................................................................................................................... 37

Table 4. 7: Maintenance Dredging ............................................................................................................. 37

Table 4. 8: Ancillary Works ........................................................................................................................ 38

Table 5.1: Major tidal constituents ............................................................................................................. 50

Table 5.2: The classification of the tides based on F-ratio scale ............................................................... 53

Table 5.3: Results of harmonic analysis of water levels in Liwatoni .......................................................... 54

Table 5.4: Results of harmonic analysis of current velocities in Kilindini harbour ..................................... 57

Table 5.5: Tidal statistics, amplitudes and phases based on harmonic analysis ...................................... 62

Table 6.1: Water column biota (phytoplankton) in three divisions of Port Reitz, Kilindini and the Entrance

Harbour ...................................................................................................................................................... 93

Table 6.2: Species composition of landed fish/crustacean (including target species for the area- frame

survey data 2006) ...................................................................................................................................... 97

Table 6.3: Total fish production and value for the last 4 years in Port Reitz and Likoni ............................ 99

Table 6.4: Benthic invertebrate assemblages at the Port Reitz, Shelly and Nyali Beach waters based on

10 transect observations (September – November 2006) ....................................................................... 104

Table 6.5: Summary of percentage cover of the major substrate categories in the four studied sites ........... 105

Table 6.6: Summary of the number of hard coral genera observed in the studied sites. ........................ 105

Table 6.7: Sea grass species at some sites of the Port of Mombasa ...................................................... 106

Table 6.8: Main seaweed genera at two sites of the Port of Mombasa ................................................... 108

Table 6. 9: Mangrove community structure at the study plots in Port Reitz basin ................................... 109

Table 6. 10: Average densities of fish and standard deviations for the four marine parks. 12 transects of

250 m2 in each park in two seasons ........................................................................................................ 112

Table 6.11: Average densities of invertebrates and standard deviations for the four marine parks. The

data was collected in 12 transects of 250 m2 in each park in two different seasons ............................... 113

Table 6.12: Percentage benthic cover per 10 m transect and the standard deviation ............................ 113

Table 6.13: Avian species at the Port Reitz based on 12 repeated observations (2 x low tides, 2 x high

tides, 2 x mornings, 2 x evenings, and twice at two fish-landing sites (Kwa Kanji and Kwa Skembo) during

fish landings (flooding tides) between September – November 2006. .................................................... 115

Table 6.14: Timing for recovery of seabed habitats after dredging (after Ellis 1996) .............................. 134

Table 10.1: Parameters for monitoring 150

Table 10.2: Monitoring of mitigation measures ........................................................................................ 150

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LIST OF PLATES

Plate 6.1: Photo A - C: Part of the ecological team, including divers, and some sampling equipment

aboard hired boats used in survey ............................................................................................................. 83

Plate 6.2: Photo D – F: Plankton sampling, microscopic survey and computer-aided taxonomic analysis.

................................................................................................................................................................... 84

Plate 6.3: Photo G – O: Field survey of rare / critical ecological fish types and ID (top) socio-economic

(gear - mid and catch - bottom) for fish, shell-fish and prawn collections. ................................................. 88

Plate 6.4: Photo P - R: Bird survey on mangrove tress and tidal flats ....................................................... 88

Plate 6.5: Photo S – U: Sediment field survey and processing for benthic collections and laboratory ID

using microscopy and technical guides. .................................................................................................... 89

Plate 6.6: Photo V – X: Hard substrata survey and collections for laboratory ID from 25m2 quadrants .... 90

Plate 6. 7: Photo Y – AA: Coral field survey and some coral genera and associated invertebrates

encountered ............................................................................................................................................... 91

Plate 6.8: Photo AB – AD: Mangrove field survey for plant structure and associate macro-invertebrates 92

Plate 8.1: An elderly fisherman gives his contribution during the consultation stage .............................. 127

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CERTIFICATION

Certification by Lead Expert (I): I hereby certify that the environmental impact assessment report has been done under my

supervision and that the audit criteria, methodology and content reporting conform to the

requirements of the Environmental Management and Coordination Act, 1999.

Signature_________________________ Date _______________________ Name___________________________________________________________ Address_________________________________________________________ Certificate of Registration No________________________________________ Certification by Lead Expert (II): I hereby certify that the environmental impact assessment report has been done under my

supervision and that the audit criteria, methodology and content reporting conform to the

requirements of the Environmental Management and Coordination Act, 1999.

Signature_________________________ Date _______________________ Name___________________________________________________________ Address_________________________________________________________ Certificate of Registration No________________________________________

Certification by Proponent We, Kenya Ports Authority hereby confirm that the contents of this report are true and will

implement practicable mitigation measures proposed in the report.

Signed for and on behalf of Kenya Ports Authority: Name_____________________________________________________________ Signature___________________________ Date ________________________ Official Rubberstamp ________________________________________________

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EXECUTIVE SUMMARY

This Environmental Impact Assessment Study report relates to the proposed Dredging of the

Access Channel and the Turning Basin at the Port of Mombasa. Over the last few years there

has been rapid increase in national and international container volumes. This requires KPA to

improve existing waterside facilities and undertake port expansion and modernization projects.

The proposed project involves dredging of the access channel comprising of the navigation

channel at port entrance, the navigation channel at inner port and the turning and anchorage

basins at the proposed Kipevu West Container Terminal. Also incorporated into this project is

maintenance dredging at the existing berths 1-19 as well as installation of associated navigation

aids. In addition this project has been made necessary as a result of the world wide trend

towards use of post-panamax vessels which are bigger than the ones the port is currently

receiving. Further there has been increasing competition from other ports such as Dar Es

Salaam and Durban and these calls for better efficiency in service delivery reflected by vessel

turn-around time and time taken to haul the cargo to the end users.

The projected dredge volumes are as follows: Access Channel (C1 – C6) - 0.6 million m3

Turning basin (C7 – C9) - 4.5 million m3

Anchorage Basin (C 10) - 2.9 million m3

Maintenance dredging (M1 – M4) -0.2 million m3

The study has taken into account the following: Background information on the project area as well as any adjacent or remote areas likely to

be affected by the project;

A description of the physical, biological and socio-economic environment of the project area;

A description of legislation, regulations and standards, and environmental policies

applicable to the proposed project, and identification of the applicable authority jurisdictions;

Identification of impacts (both positive and negative) related to dredging and disposal of

dredged materials;

An outline of mitigation measures to prevent or reduce significant negative impacts to

acceptable levels as well as measures to minimise disruption to existing port operations;

An environmental monitoring plan to ensure that the proposed mitigation measures are

implemented, and the measures are effective addressing the adverse impacts;

A proposal for review of the environmental management plan in tandem with project

progress so that it addresses issues arising from periodical monitoring.

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This study has established that the water quality around the Port of Mombasa is poor as a result

of contamination from waterfront activities. It is however acceptable for recreation purposes.

The study encountered high levels of Cd and As in sediments from the Turning Basin

attributable to anthropogenic sources, especially, the wastewater discharge from the municipal

sewage treatment facility at Kipevu. It is therefore recommended that the contaminated dredged

material from this area should not be disposed at sea. The contaminated sediments would

therefore be disposed in a containment facility to be constructed at the site of the proposed

container terminal project in Port Reitz. With this arrangement the contained material would also

act as landfill for the reclamation site.

This study established that the project area has two types of sediments: The hard substrate material at the access channel and at the navigation channel at inner

port. This material, totaling approximately 0.6 million m3 would be dredged by a grab

dredger and be deposited at the site of the proposed container terminal in Kipevu where it

would act as landfill in the reclamation exercise;

Soft, silty material at the turning and anchorage basins totaling 7.4 million m3 to be dredged

by trailing suction dredger. The uncontaminated material from the anchorage basin would

be deposited offshore while the contaminated material would be deposited at the reclaimed

area in the proposed Kipevu Container terminal with containment.

Key adverse negative impacts identified in this study include:

Temporary disruption of fishing activities as a result of increased vessel traffic during the

dredging period;

Turbidity of water column as a result of release of sediments (particulate) during dredging

and offshore dumping. This would obstruct visibility thereby temporarily impairing activities

of fishers;

Possible interference with normal port operations such as ships docking and ferries plying

passengers across the Likoni Channel.

Mitigation measures proposed include:

Use of appropriate dredging methods to minimize physical impacts. Sediment quality

analysis undertaken as part of the EIA identified Grab Dredger method for hard material and

Trailing Suction Dredger for the soft material.

The project would be undertaken in consideration of seasonal variations and wind patterns

to limit the extent of propagation of sediments during dredging and dumping

The proponent shall arrange a compensation package for fishermen who lose their

livelihood during the course of the project. Such compensation includes provision of

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motorized boats to enable fishers venture further offshore and/or monetary support for the

affected fishers.

A detailed monitoring programme has been prepared to assist in tracking the progress of

implementation of the environmental management programme. The programme is to be

implemented by the contractor, the proponent and a consortium of stake holders comprising of

Lead Agencies and Non-Governmental Organizations (NGOs). This study therefore

recommends that the proposed project be approved subject to implementation of the proposed

environmental management and monitoring plan.

1

1.0 INTRODUCTION

1.1 Overview of the Project

The Port of Mombasa has experienced considerable growth in the past 5 years in

particular in the container segment. The port currently handles approximately 500,000

TEU’s per year and demand forecast show that there will be a steady increase in

container throughput at the port to approximately 1,600,000 TEU’s per year by the year

2030 (SAPROF, 2006). This factor, coupled with the worldwide trend towards larger

(post-panamax) ships, stresses the need for expansion of the Port. For the port of

Mombasa to meet these demands and become a destination for major trucking routes

there is a necessity to dredge the Turning Basin in front of the proposed new Container

Terminal and navigation channels to the Port of Mombasa to allow for the bigger ships to

dock at the port (Fig. 1.1).

Mombasa Port comprises of four harbours. These are from the north-western extreme:

Port Reitz (within the Port Reitz creek), Kilindini harbour (on Kilindini creek serving as

the main harbour port of Mombasa), entrance harbour (near the confluence of Kilindini

and Tudor creeks) and Tudor harbour (within Tudor Creek and serving the old port). The

Kilindini and Port Reitz harbours have between them 16 deep water berths with an

average of 10 m draft and a total length of 3044 m; two bulk oil jetties and one cased oil

jetty; two container terminals with a total length of 964m; two bulk cement berths with

cement silos, each with 6000 tone capacity; two lighterage and dhow wharves; and one

explosives jetty. Currently the area to the west of Kipevu Oil Terminal is planned for

construction of a new modern container terminal with 3 berths (KPA, 2005; Saprof 2006;

Adala et al. 2007).

The proposed dredging project involves deepening and widening of the navigation

channel to the port of Mombasa and at the turning basin in front of the proposed Kipevu

West container terminal at Port Reitz. It would therefore affect the 3 harbours of Port

Reitz, Kilindini Port and Entrance Harbour. Also incorporated into the project is

maintenance dredging at the existing berths 1-18. The required dredging volumes at

Turning Basin, Navigation Channel at Inner Port and Port Entrance are estimated at 4.7,

0.2 and 2.4 million m3, respectively.

2

Figure 1.1: Locations of Capital Dredging Works

Most of the dredged materials will be disposed at a planned offshore dumping site

located about 6km offshore from the port entrance. Sandy or hard materials extracted

from the access channel and from the navigation channel at inner port will be utilized as

filling materials for reclamation of the site for the proposed new Container Terminal.

1.2 Justification for the Project 1.2.1 Rapid increase in volume of containerized cargo The port currently handles various cargoes including dry bulk, liquid bulk, conventional

cargo and containers. Most of the cargoes are increasing and, among them, the growth

of the container cargo is very high recording 380,000 TEU in 2003 and 439,000 TEU in

2004 (Figure 1.2)

This volume of the container cargo already exceeds the estimated capacity of the

existing container terminal and neighboring berths of Mombasa Port that is

approximately 400,000 TEU/year. It is forecasted that the growth of the container cargo

will continue and within ten years, the containerized cargo volume will be doubled.

3

Dredging of the access channel is therefore necessary to take care of increased volume

of port traffic.

Figure 1. 2 Container traffic at the Port of Mombasa 1997 – 2004

1.2.2 Competition from other ports

Increasing competition from other ports such as Dar Es Salaam and Durban, among

other regional ports calls for better efficiency in service delivery in terms of vessel turn-

around time and time taken to haul the cargo to the end users. This inherently calls for

better maneuverability of ships and other marine traffic within the port, a situation that

would be enhanced by the proposed dredging project.

In addition the current global economic recession has impacted adversely on the

shipping industry thereby making the industry more sensitive to logistics and tariffs. The

proposed dredging project is expected to open up the port for larger volumes of cargo

and economies of scale would as a result imply tariff revision to induce more business

for the expanded port.

1.2.3 Worldwide trend towards use of the larger post-panamax ships

To optimize freight costs shipping lines are increasingly moving towards utilization of

post-panamax ships. These are ships with overall length more than 300m, width >33m

4

and air draft more than 60m measured from the water line to the vessel’s highest point.

These ships typically have a displacement of approximately 65,000 tonnes, meaning that

they are designed to transport the maximum amount of cargo in a single vessel.

Because of the large sizes of these ships they require deeper berths for docking and

deeper and wider channels for navigation. The current depths of the berths and access

channel at Mombasa Port renders it unsuitable for use by post panamax ships, and the

dredging project needs to be undertaken to avoid risk of Mombasa port being relegated

to a feeder port.

1.2.4 Vision 2030

This is the government of Kenya’s development blueprint prepared in mid 2007, which

charters the countries development strategy in all sectors and aims to make the country

a newly industrialized, middle income nation, providing high quality of life to it’s citizens

by 2030. This vision came into play after the successful implementation of the Kenya

Economic Recovery Strategy for Wealth and Employment Creation 2003 – 2007, which

witnessed a rise in the countries GDP from 0.6% to 6.1% in 2006 (World Bank)

The economic pillar of Vision 2030 aims at providing prosperity to all Kenyans through

and economic development programme aimed at achieving an average GDP growth rate

of 10% per annum in the next 25 years. The social pillar sees to build a cohesive

society with social equity in a clean and secure environment.

In order to achieve a GDP of 10%, the whole sale/ retail trade sector, the Mombasa port

into a free Trade Zone similar to Dubai has been proposed as a flagship project. For this

to be achieved, it is imperative for the port to undergo modernization and expansion to

match worldwide trends

5

1.3 Present Environmental Conditions within Mombasa Port and its Environs

1.3.1 Water quality

Water quality within the port has deteriorated due to both onshore and offshore activities.

Main sources of pollution include:

Marine Vessels: Both cargo vessels and the port’s marine craft pose risk of water

pollution discharges (accidental release of fuels or lubricants). This may come as a

result of vessel collisions, vessels running aground or vessels colliding with stationary

structures.

Operations: Cargo operations especially liquid bulk from port users (oil marketing

companies, importers and exporters of edible oils). Spillage may occur during truck

loading, pumping or faulty tankers. In most cases the spill finds its way into surface

water drain and eventually into the sea.

Figure 1.3: Spill of soda ash from Magadi Soda conveyor belt

Dry Cargo releases: There have been complaints of excessive dust releases during

offloading of coal or clinker (for Bamburi Cement), soda ash (for Magadi Soda, Figure

1.3) and occasionally during discharge of bulk grain (Grain Bulk Handlers Ltd). Some of

6

the material finds its way into the ocean raising the Chemical Oxygen Demand (COD) to

levels that may not be conducive for the survival of marine life.

Water front industry discharges: Industries in the neighbourhood of the port discharge

untreated sanitary and industrial wastes into the sea. There is also effluent from the

Municipal sewage treatment plant (Figure 1.4) that is currently not functioning

consequently discharging raw sewage into the sea. Unfortunately this situation still

prevails.

Studies have indicated that the water quality in the area is already poor, rich in nutrients

and contaminated with high concentrations 0of heavy metals. Pollution by faecal matter

has also been reported by Kamau (2001), while that for oil has been reported by

Norconsult (1975) and Munga et. al (1993).

Figure 1.4: Untreated effluent from Municipal treatment plant discharges to sea

Part of the pollution was for a long time attributed to the Municipal Dumpsite at Kibarani

near Makupa Creek. The dumpsite was decommissioned in 2002 and is now only used

as a holding site for transshipment of waste to the current dumpsite located at

Mwakirunge in the mainland north.

High nutrients 0.2-36 mg/l subset nitrates, 0.1-7.7 mg/l subset reactive phosphate and

indicator bacteria 13-90,000 coliforms/100ml, 13-17,000 E-coli/100ml, have been

7

reported in the adjacent Makupa Creek, (Mwangi et.al). This water of low quality finds its

way into the Kilindini creek, which also receives its own share of untreated sewage.

Despite this, the area has shown resilience with an abundance of copepods. It can be

predicted with a fairly good degree of certainty that the status quo can be maintained

even with the proposed dredging project and subsequent marine operations in the area.

This prediction should be understood in the light that the project will not introduce any

nutrient rich materials, nor will it generate large volumes of human waste.

1.3.2 Air quality Presently sources of air pollution within the port include: Dry Cargo Releases: As described above there is release of significant quantity of dust

into the environment during offloading of dry cargo. Some of this is released as fine

airborne dust, thereby lowering the ambient air quality standards (Figure 1.5)

Figure 1.5: A grab discharging clinker into a truck

Road Traffic: Traffic within the port generates fugitive dust from unpaved roads and road

shoulders. A considerable number of local delivery trucks are poorly maintained and

emit thick black smoke with considerable quantities of carbon monoxide.

8

Port Equipment: Equipment such as forklifts, tug-masters, trailers also emits pollutants

into the environment. Although most port equipment are well maintained they are quite

many in number and this combined with the frequency of use (most container handling

equipment are used continuously for 24 hours) makes the emission from equipment

significant.

As part of the EIA process SGS Kenya Limited were contracted to carry out air quality

measurements at 5 points along the Kenyan coast at Mombasa on various dates

between 3rd November 2007 and 7th November 2007. The measurements were to

identify the concentration of pollutant releases in the land based receptor areas. The

pollutants targeted in the air quality measurements were Carbon Monoxide (CO),

Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2), Hydrogen Sulphide (H2S) and Particulate

Matter (PM). SGS Kenya Limited is accredited by NEMA for environmental sample

collection and analysis. The results are as shown in the appendix.

On the basis of the measurement results, the survey results were found to be within the

World Health Organization Air Quality Guideline Values. The prescribed WHO values for

the key pollutants Nitrogen Dioxide and Sulphur Dioxide are 200µg/m3 per 1hr mean and

500µg/m3 per 10 minute mean respectively. It was concluded therefore that other than

occasional incidents of fugitive releases the current air quality within the port does not

present risk to human health. During project implementation continuous monitoring

would be undertaken to establish whether there would be further degradation attributable

to project activities.

1.3.3 Sediment quality

Previous studies have indicated certain areas of the port are contaminated with heavy

metals. However approximately 95% of the samples extracted during the study

indicated levels that fall within the acceptable concentration levels for open water

disposal (Testing Values) presented in World Bank Technical Paper No 126, 1990. All

dredged material that is classified as contaminated will be placed in contained land

based receptacles within the proposed container terminal reclamation area.

1.3.4 Ecosystem

Notable conservation areas in the neighbourhood of the Port include:

9

♦ The Mombasa Marine Park: Located about 15 km from the proposed site;

♦ Shimba Hills National Park: This is located in Kwale District, approximately 50 km

from the site.

The Ecosystem around Mombasa Port and the project area is covered in greater detail

in Chapter 6 of this report.

1.4 Terms of Reference for Environmental Impact Assessment The following Terms of Reference for the Environmental Impact Assessment (EIA) of the

proposed Dredging Works at Mombasa Port were adapted in accordance with the World

Bank and NEMA environmental impact assessment guidelines.

1. Introduction – The consultants would identify the development project to be

assessed and explain the executing arrangements for the environmental

assessment. This chapter of the report would detail the rationale for the

development and its objectives. Also to be covered is the context of the proposed

project in relation to future plans for development of Mombasa Port.

Deliverable: A detailed project outline would be given to familiarize stakeholders on the project objectives and scope.

2. Background Information – The experts would highlight the major components of

the proposed project, the implementing agents, a brief history of the project and

its current status including a justification as to whether the project is indeed

necessary.

Deliverable: Major project components will be documented, including

current and projected container volumes and project justification made.

3. Study Area – Specification would be made of the boundaries of the study area as

well as any adjacent or remote areas considered to be affected by the project

such as dredged material disposal sites.

Deliverable: Study areas to be clearly identified so that all social and

environmental issues are catalogued and analysed.

4. The following tasks will be performed:

Task 1. Description of the Proposed Project - a full description of the relevant

parts of the project, using maps at appropriate scales where necessary. This is

10

to include: quality and volume of sediments to be excavated in each area to be

dredged; type of dredging equipment to be used and the manner of deployment

including handling, transportation, and disposal of dredged material, sediment

containment settling and turbidity control measures; alternative dredging

methods considered; project schedule; and life span.

Deliverable: This would include a detailed project description and scope,

and the options available for achieving the project objectives.

Task 2. Description of the Environment - Assemble, evaluate and present

baseline data on the relevant environmental characteristics of the study area

(and disposal sites), including the following:

a) Physical environment: geomorphology, meteorology (rainfall, wind, waves

and tides), sea currents and bathymetry, surface hydrology,

estuarine/marine receiving water quality, and ambient noise.

b) Biological environment: terrestrial and marine vegetation and fauna, rare

or endangered species, wetlands, coral reefs, and other sensitive habitats,

species of commercial importance, and species with the potential to

become nuisances or vectors.

c) Socio-cultural environment: shipping and fishing activities and use of the

port, population, land use, planned development activities, employment,

recreation and public health, community perception of the development,

vulnerable occupants. Field survey would also e conducted on the

number of households to be displaced and areas of resettlement and land

acquired for the project.

d) Hazard vulnerability; vulnerability of area to flooding, hurricanes, storm

surge, and earthquakes. Also to be included here is maritime accident

data including ship collision, oil spill from ships and from land based

industrial activities.

The consultants would characterize the extent and quality of the available data,

indicating significant information deficiencies and any uncertainties associated with

the prediction of impacts.

11

Deliverable: Baseline environmental information, comprising physical,

biological and socio-economic conditions associated with the site will be

assembled and evaluated, including assumptions and limitations.

Task 3. Legislative and Regulatory Considerations – A description of the

pertinent legislation, regulations and standards, and environmental policies that

are relevant and applicable to the proposed project, and identification of the

appropriate authority jurisdictions that will specifically apply to the project.

Deliverable; All relevant legislative, regulatory and institutional

arrangements applicable to project will be summarized and presented.

Task 4. Determine the Potential Impacts of the Proposed Project –

Identification of impacts related to dredging, spoil disposal and possible land

filling. Also to be identified are impacts related to road construction, land

reclamation and construction of office buildings and associated facilities. A

distinction will be made between significant impacts that are positive and

negative, direct and indirect (= triggering), and short and long term. Identify

impacts that are cumulative, unavoidable or irreversible. Identify any information

gaps and evaluate their importance for decision-making. Special attention will be

paid to:

• Effects of the project (dredging and spoil disposal) on water quality and

existing coastal ecosystems and resources,

• Effects of dredging on the coastal stability of adjacent shorelines,

• Effects of dredging works on the existing operations of the port, fishermen,

and on the rights/operations of any other stakeholders,

• Effects of the project on future port development and the tourism sector,

• Effects of the project on maritime, boating and road traffic,

• Effects of the project on ambient noise levels, and

• Effects of the project on any historical resources.

Deliverable: All potential impacts (both positive and negative) likely to

result from the development will be identified and ranked in an

environmental impact matrix.

12

Task 5. Analysis of Alternatives to the Proposed Project. – A Description of the

alternatives examined for the proposed project that would achieve the same

objective including the “no action” alternative. This includes dredging vessel

types and disposal sites, alternative traffic routes and alternative resettlement

plans. Distinguish the most environmentally friendly alternatives.

Deliverable: Project alternatives would be identified and analysed and a

justification made as to why the chosen sites, methods and plans

constitute the best practicable environmental option.

Task 6. Mitigation and Management of Negative Impacts – The consultants will

identify possible measures to prevent or reduce significant negative impacts to

acceptable levels with particular attention paid to dredge spoil disposal and

dispersal/sedimentation control, as well as measures to minimise disruption to

existing port operations. Costing will be made of the mitigation measures and

equipment and resources required to implement those measures. Proposals will

be made for investigating claims for compensation put forward by affected

stakeholders.

Deliverable: A detailed environmental management programme will be developed to reduce the effects of the negative environmental impacts and enhance the impacts considered beneficial to the proponent and the community.

Task 7. Development of a Monitoring Plan – Identify the critical issues requiring

monitoring to ensure compliance to mitigation measures and present impact

management and monitoring plan for such issues.

Deliverable: An environmental monitoring plan will be prescribed to ensure

that the proposed mitigation measures are effected and the desired

remediation effects achieved.

Task 8. Assist in Public Participation and Consultation

The consultants would identify appropriate mechanisms for providing information

on project activities and progress of project to stakeholders, assist in co-

coordinating the environmental assessment with the relevant government

agencies and in obtaining the views of local stakeholders and affected groups. (It

is anticipated that there will be considerable public interest concerning issues of

13

sediment disposal and turbidity with respect to fishing activities, and the

economic benefits to be derived from the project.)

Deliverable: Public consultation will be conducted and stakeholder views

documented. Where necessary the consultants would conduct stakeholder

workshops to collect and collate stakeholder views.

Report - The environmental impact assessment report, to be presented in electronic

and hard copies, will be concise and focus on significant environmental issues. It will

contain the findings, conclusions and recommended actions supported by

summaries of the data collected and citations for any references used in interpreting

those data. The environmental assessment report will be prepared in the format

prescribed by NEMA, the outline of which is as follows:

• Executive Summary

• Description of Proposed Project

• Policy, Legal and Administrative Framework

• Identification of Environmental Impacts

• Impact Mitigation Measures

• Impact Monitoring Plan

• Public Consultation and Participation Process

• Appendices/List of References

1.5 Consideration of Alternatives

1.5.1 Alternatives of sites for dumping of dredged material

The following sites were considered for dumping of the dredged material:

1.5.1.1 Alternative A: Open water dumping

One of the areas considered is a site offshore with a depth of 100m and a distance of

about 3 km from entrance of the Port as indicated in Figure 1.6. The advantage of this

site is that it is strongly influenced by the East African Coastal Current that flows

northward all the year round. The topography is such that the bottom drops steeply from

14

40 m to 200 m depth within a distance of less than 3km away from the fringing coral reef

found in this area.

Figure 1. 6: Alternative locations for proposed dumping sites

This means materials disposed at Alternative site A beyond the reef front are placed in

the path of the main coastal current and have limited chance of drifting back to the

shallow areas and impacting on the ecosystems such as corals reefs and seagrass beds.

The area considered for disposal is within the limits of the Port and has been used

before for dumping of dredged material from the harbor channel. The seabed material at

100 m is likely to be fine mud similar to the disposal material and hence would not

introduce significant impact.

1.5.1.2 Alternative B: Land based dumping

PROPOSED CONTAINER TERMINALPROPOSED CONTAINER TERMINALPROPOSED CONTAINER TERMINALPROPOSED CONTAINER TERMINAL

BASIN/ACCESS CHANNEL DREDGINGBASIN/ACCESS CHANNEL DREDGINGBASIN/ACCESS CHANNEL DREDGINGBASIN/ACCESS CHANNEL DREDGING (RELEVANT PROJECT)(RELEVANT PROJECT)(RELEVANT PROJECT)(RELEVANT PROJECT) Shelly Beach

Nyali Beach

Limit of Port Mombasa

Mombasa Marine

National Reserve

AlternativeAlternativeAlternativeAlternative---- AAAA AlternativeAlternativeAlternativeAlternative---- BBBB

15

Another alternative is to dump the dredged material at the land based disposal site on

Mombasa West mainland at the site of the proposed container terminal in Port Reitz.

The material would then act as backfill in the area where 100 hectares is proposed for

reclamation from the sea. This site is also proposed for dumping of contaminated

sediments. In such case KPA shall equip the site with containment facilities such as

installation of enclosing concrete or steel wall or use of thick plastic sheets such that the

dumped material does not contaminate soil or groundwater.

1.5.2 The No Action alternative

The selection of the “No Action” alternative would mean the sea being retained in its

existing form. As mentioned in sec. 1.2 the trend worldwide is that the shipping industry

is moving towards use of post-panamax ships. The current depths of the berths and

access channel at Mombasa Port renders it unsuitable for use by post panamax ships,

and the dredging project needs to be undertaken to avoid risk of Mombasa port being

relegated to a feeder port.

The “No Action” Alternative is likely to have the greatest negative implications on the

socio-economic environment of the area and surrounding communities. It is anticipated

that the proposed development would provide opportunities for employment both at the

construction and operation stages and potentially significant business opportunities

would spring up as a result of its implementation. All these benefits would be foregone if

the project is not undertaken.

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2.0 BASELINE INFORMATION

2.1 Landscape, Topography and Geology The Mombasa District is situated in coastal lowland with extensive flat areas rising gently

from 8 meters above sea level to 100 meters above sea level in the west. It can be

divided into three main physiographic belts, namely, the flat coastal plain, which is 6

kilometres wide, and includes the Island division, Kisauni on the north mainland and

Mtongwe to the south. Next, are found the broken, severely dissected and eroded belt

that consists of Jurassic shale overlain in places by residual sandy plateau found in

Changamwe division. Finally, there is the undulating plateau of sandstone that is divided

from the Jurassic belt by a scarp fault. Nearer the sea, the land is composed of coral

reef of Pleistocene Age that offers excellent drainage. The coral limestone and lagoon

deposit reach a thickness of 100 meters.

2.2 Climate

The Port of Mombasa lies in the hot tropical region where the weather is influenced by

the great monsoon winds of the Indian Ocean, which also influences the climate and

weather systems that are dominated by the large scale pressure system of the western

Indian Ocean and the two distinct monsoon periods. Comparatively dry weather

conditions are experienced in the area from November/December to early March, when

the North-East Monsoon predominates. Detailed climatic description will be found in the

section under description of the physical environment.

2.3 Hydrology There are no permanent rivers in Mombasa. However, due to favourable geology,

groundwater sourced from shallow wells and boreholes is available to supplement the

needs of the residents. Otherwise, water to serve the needs of the area is sourced from

Kwale through Marere Springs and the Tiwi Boreholes; Malindi through the River Sabaki;

and from the Mzima springs in Taita Taveta District.

It is however of note to state that there are number of semi-perennial and seasonal

rivers such as the Mwache, Kombeni, Tsalu, Hodi-hodi and Nzovuni, which drain into

coastal region from arid and semi-arid catchments.

17

Mombasa has some potential in terms of groundwater resources. This is because of its

geological structure that promotes rapid infiltration and percolation of surface run-off to

recharge groundwater aquifers. Areas covered with the Kilindini sands have a high

groundwater potential so are the areas with Triassic sandstone geology, which have

shown high groundwater yields.

Four main types of groundwater have been identified in the Kenya coast according to

their anionic content: carbonate, bicarbonate, chloride and sulphate. Mixed types of

groundwater composed of the above have also been found in the Kenya coast.

The main factors controlling the quality of groundwater are the permeability of the rock,

the rock type and degree of recharge from surface run-off and rainfall. Water of the

poorest quality (high TDS) is associated with the Jurassic shale; intermediate water

quality is associated with the Triassic sandstones and Pleistocene coral limestone; while

the best quality is associated with the unconsolidated sands that receive efficient

recharge due to their high infiltration capacities.

Groundwater quality also varies depending on the depth of the borehole/well, nearness

to the ocean and proximity to human settlements. Boreholes located near the coast have

a problem with salt water intrusion and this problem is exacerbated by over-extraction.

Boreholes and wells located in urban areas suffer from the threat of pollution originating

from pit latrines and septic tank-soakage pit systems, which are often the source of

contamination to otherwise good quality water chemically rendering it unsuitable for

drinking purposes.

The exploitation of groundwater in Mombasa has been haphazard with no strict

government control on borehole drilling or well development. With the current problem of

water supply shortages and increased urban-rural population, people in urban areas,

especially Mombasa, are increasingly dependent on groundwater for potable needs.

2.4 Soils

The soil types in the Port of Mombasa area are broadly associated with the geological

formations along the physiographic zones in Mombasa district as detailed by the Ministry

of Agriculture, Government of Kenya (1988). Along the coastal lowlands, four soil types

predominate:

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♦ On the raised reefs along the shore, well-drained, shallow (< 10 cm) to moderately

deep, loamy to sandy soils predominate;

♦ On unconsolidated deposits in the quaternary sands zone (also referred to as

Kilindini sands) are well drained moderately deep, to deep, sandy clay loam, to

sandy clay, underlying 20 to 40 cm loamy medium sand;

♦ In the Kilindini sands zone are also to be found areas with very deep soils of varying

drainage conditions and colour, variable consistency, texture and salinity;

♦ Also found on the Kilindini sands are well-drained very deep, dark red to strong

brown, firm, sandy clay loam to sandy clay, underlying 30 to 60 cm medium sand to

loamy sand soils;

In the coastal plain, the soils are developed on coral limestone merging to Kilindini sands

inland. The coral soils are generally well drained and of sandy clay loam to sandy clay

texture. They range from very deep and non rocky to very shallow and extremely rocky.

The soils developed on Kilindini sands vary from excessively drained, very deep, very

sandy soils to poorly drained, very deep, heavy clay soils. Extensive areas of imperfectly

drained, clayey soils occur in the southern part of the coastal plain.

Most of the agricultural activities in the district occur in the mainland areas, i.e. Kisauni

(north mainland), Likoni (south mainland) and Changamwe (west mainland). The low-

lying areas are dominated by the coconut-cassava and cashew nut-cassava agro

ecological zones (GOK Ministry of Agriculture 1988).

Most of the Mombasa island area and parts of Kisauni and Likoni fall under the coconut-

cassava zone. This zone is characterised by a medium to long cropping season and

intermediate rains. The rest of the low lying areas in Kisauni and Likoni fall under the

cashew nut-cassava zone, which is characterised by medium cropping season, followed

by intermediate rains.

Most of the raised Changamwe area falls under the cashew nut-cassava zone. The

raised areas in Kisauni and parts of Changamwe, that mainly include the shale areas,

fall under the lowland livestock-millet zone. This zone is characterised by a short to

medium cropping season and a second season with intermediate cropping.

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2.5 Population According to the 1999 Population and Housing Census (GOK, 1999) the population of

Mombasa District stood at 665,000 persons distributed in the four divisions’ of the

District as indicated in Table 2.1. The projected population for the district in 2005 is also

given.

Table 2. 1. Population distribution in the Mombasa District

Administrative

Division

Size:

Area km2

Population Population density/ km2

2005 1989 1999 2005*

Island 14.1 127,720 146,334 170,699 12,106

Kisauni 109.7 153,324 249,861 291,463 2,657

Likoni 51.3 67,240 94,883 110,681 2,158

Changamwe 54.5 113,469 173,930 202,889 3,723

TOTAL 229.6 461,753 665,018 775,743 3,379*

Source: GOK (1989, 1999). * Projected

Mombasa district experienced a 44% increase in population between the census years

of 1989 and 1999. Changamwe Division has the second highest number of people in the

District. Kisauni Divisions’ population grew by 63% in 10 years’ period. The high

increase in population was attributed to natural growth and in-migration, mostly of the

labour force from other parts of the country. Generally, the high population in Mombasa

has proved to be a serious challenge in the provision of housing and essential services

such as water, sanitation and health care.

2.6 Demographic Characteristics The Island division of Mombasa district is the Central Business District (CBD). It is the

most built up area and has the highest population density. High cost low-density

settlements within the Island are found in Kizingo and Tudor, while middle cost, high-

density settlements are found around the Buxton-Stadium area, Makupa and Saba Saba.

Then we have the low cost high-density settlements found around Buxton, Tononoka,

and Old Town. Informal and slum settlements found on the Island include Muoroto

20

California, Muoroto Paradise, Muoroto Kafoka, Kiziwi, Kaloleni, Spaki, Sarigoi/Mwembe

Tayari, Mwembe Taganyika and Kibarani.

A land use classification study (Agil Saleh, 1999) indicates that only 31.2% of the total

land area in Mombasa district is under residential settlements. The direction of growth in

human settlements is found concentrated northwards in Kisauni Division where other

socio-economic activities occupy large parcels of land. This has entailed the crowding of

many people in small land areas with many implications. For example in the Kisauni

division, large beef and dairy farms, the tourist hotels, Shimo La Tewa School and

Prison and Bamburi Cement, occupy large tracts of land. The result of this is population

concentrations in the sprawling low cost high density settlements of Kisauni Estate,

Mlaleo, Barsheba, Mwandoni, Bakarani, Magogoni, Mishomoroni, Mtopanga, Shanzu;

and the squatter areas of Ziwa la Ngombe, Kisimani and the Bombolulu slums.

A similar situation exists in Likoni and Changamwe divisions, where large pieces of land

having been reserved for productive economic activities, people have been left to

concentrate on small areas in several informal settlements. Such of the areas include

Maweni, Timbwani, Kidunguni, Ujamaa/Shika-Adabu, and Mtongwe (Shonda) all in

Likoni division. In Changamwe division, concentrations of human settlements are found

at the Chaani conglomerate areas of California, Dunga Unuse, Tausa, Kwarasi, and

Migadini. Other informal settlements and slums are found at Kasarani, Fuata Nyayo,

Kalahari, Birikani, Kwa Punda, Bangladesh, Gana Ola, Mikanjuni, Miritini Madukani,

Vikobani, Mwamlali, Cha Munyu, Magongo-Wayani, and Jomvu Kuu. These are areas

where the sanitation status is poorest: crowded human settlements and generally poor

infrastructure facilities resulting in a myriad of environmental problems as a

consequence (Gatabaki-Kamau et al., (2000).

2.7 Physical Infrastructure 2.7.1 Sea, road, rail and airport networks Sea transport in Mombasa is provided by the Port of Mombasa. The major exports from

the port of Mombasa are coffee, petroleum products, meat and meat products, hides and

skins, cement, pineapple, and tea. Main imports include industrial and electrical

machinery, crude petroleum, assembled motor vehicles and chassis, iron and steel,

21

agricultural machinery and tractors, pharmaceuticals, fertilizers, textiles, mineral fuels,

chemicals, food and live animals.

Most of the roads in the Mombasa District converge on the city due to its importance as

an industrial and commercial centre. The district is well served by both classified and

unclassified roads, although the network is not equally distributed with many of the roads

being concentrated on the Mombasa/West Mainland axis. This has left the north/south

mainland areas with few vehicular roads and this is a contributing factor in the relative

underdevelopment of these parts.

It has been estimated that nearly 75 % of all goods imported and exported through the

Port of Mombasa are conveyed by road, underlying the importance of this means of

transport. The main exception to this is oil products, which are conveyed by a pipeline

into Kenya’s interior.

Rail transport between Mombasa, though important has relatively declined over the

years. The main railway line between Mombasa and Nairobi, branches off at Voi to

connect with the Taveta Town-ship. Kenya railways has large marshalling yards and

depots at Mombasa and lines extend from this into the industrial area and the port

Warehouses

Moi Airport Mombasa, is the main airport for the coast region. It is served by the

national airline as well as other flights bringing in passengers and cargo. There are

frequent flights to Nairobi as well as other less frequent ones to other areas like Malindi

and Lamu.

2.7.2 Electricity supply

Electricity is adequately provided in and around the port of Mombasa. However, the

frequent and irritating power failures, which go, unexplained are common. This hurts

many sectors of the economy. This has prompted many Mombasa business people and

enterprises to install standby generators in order to minimize business losses.

22

2.7.3 Water supply Mombasa district heavily depends on water sources from outside the district for its

needs. It supplements this water need from groundwater sources in the district. The

district has a daily water demand of 200,000 cubic meters of water against the available

130,000 cubic meters that come from the traditional supply sources of Kwale, Malindi

and Taita-Taveta. There is therefore a water shortfall of 70, 000 cubic meters, (NWCPC,

2000). This 35% shortfall is met by tapping the groundwater sources, which are potential

in the district. Also, as the reticulated supplies experience constant breakdowns,

groundwater sources, not only supplement the supply, but they sometimes become the

major source of water available in the district. In fact, 13,286 out of the 183,540

households in the district are almost permanently dependant on groundwater. These are

distributed as follows: - wells- 6,245 households, boreholes- 6,941 households (GOK,

Kenya Population Census 1999).

A significant number of the population therefore relies on groundwater for their potable

needs. As groundwater is an important source of potable water, it must be protected

from sewage pollution.

2.7.4 Housing and sanitation The study found that the main systems available for sewage management in Mombasa

district include the following: -

♦ Centralized sewers and treatment plants

♦ Septic tanks and soakage pits, and

♦ Pit latrines.

The centralized sewer system serves only a small proportion of the population in the

district. The use of septic tanks and soakage pits is largely limited to the planned areas

of development. The majority of the population is served by the use of pit latrines. About

one third of the Island is on a centralized sewer system, this serves about 12 percent of

the households.

23

3.0 POLICY, INSTITUTIONAL AND LEGAL FRAMEWORK

3.1 Introduction Among environmental challenges being experienced today include land degradation,

loss of biodiversity, solid waste management air pollution, and water management. This

situation is aggravated by lack of awareness and inadequate information amongst the

public on the consequences of their interaction with the environment. In addition, there is

limited involvement of the local communities in participatory planning and management

of environment and natural resources. Recognizing the importance of natural resources

and environment in general, the Government has put in place a wide range of policy,

institutional and legislative measures to address the underlying causes of environmental

degradation in the country.

3.2 Legal Framework The following pieces of legislations and regulations are applicable to the proposed

project:

3.2.1 The Environmental Management and Co-ordination Act, 1999

This Act enacted in 1999 brought into force the National Environmental Management

Authority (NEMA). NEMA is a corporate body responsible for the administration of the

above legislation. The Director General appointed by the President heads NEMA. NEMA

functions include the co-ordination of various environmental management activities,

initiation of legislative proposals and submission of such proposals to Attorney General

through the Minister for Environment & Natural Resources. NEMA also conducts

research, investigations and surveys in the field of environment and undertakes

environmental education and awareness. In addition, NEMA advises the Government on

regional and international agreements to which Kenya should be a party and issues of

an annual report on the state of environment in Kenya. NEMA is charged with the

responsibility of the execution of the Environmental Impact Assessment (EIA).

According to section 58 of the Act projects specified in the second schedule that are

likely to have significant impact on the environment have to be subjected to an EIA study.

Being a construction project, this project is considered to fall under the said schedule.

24

Part VII, section 68 of the same Act requires operators of projects or undertakings to

carry out annual environmental audits to determine the level of compliance with

statements made during EIA study and submit the audit report to NEMA.

Part VIII, section 72 of the Act prohibits discharging or applying poisonous, toxic,

noxious or obstructing matter, or any other pollutant into aquatic environment. Section

73 requires that operators of projects which discharge effluent or other pollutants submit

to NEMA accurate information about quantities and qualities of effluent discharged, and

that effluent generated from point sources are discharged into existing sewers only after

issuance of prescribed permit from the local authorities.

3.2.2 The Environment Impact (Assessment and Auditing) regulations, 2003

This Legal Notice stipulates ways in which environmental experts should conduct the

Environment Impact Assessment and Audits in conformity with the requirements stated.

It is concise in its report content requirements, processes of public participation,

licensing procedures, inspections and any possible offences under the Act.

3.2.3 The Occupational Safety and Health Act, 2007

This Act commenced in 2007 and replaces The Factories and Other Places of Work Act,

Cap 514. It makes provisions for the health, safety and welfare to be observed by

employers and persons employed in places of work. Part IV of the act covers health

issues such as the state of cleanliness, refuse management, employee space

requirement, ventilation and sanitary conveniences. Part V covers fire safety, operation

and maintenance of machinery, fencing requirements, storage of dangerous substances,

training and supervision of workers. Part VI deals with welfare issues; drinking water

supply, washing facilities, sitting areas and first aid provision.

3.2.4 The Water Act 2002 (No. 8 of 2002); Laws of Kenya

The Water Resource Management Authority was established under this Act to:

♦ Develop principles and guidelines for allocation of water resources

♦ Monitor and re-assess water resource management strategy

♦ Monitor and enforce permissions attached to water use

♦ Regulate and protect resources quality from adverse impacts

♦ Manage and protect water catchments

25

♦ To liaise with other bodies for better regulation and protection of water

resources

The Water Act provides for the conservation and controlled use of water resources in

Kenya. Under the Ministry of Water the Act prohibits pollution of water resources and

controls the discharge of industrial and municipal effluents into the ocean and other

water bodies.

The proposed project would impact on sea water due to dredging and disposal of

dredged material and hence is subject to the provisions of the Water Act.

3.2.5 The Physical Planning Act; Laws of Kenya, Chapter 286

This Act provides for the preparation and implementation of physical development plans.

They formulate national, regional and local development policies, guidelines and

strategies. The Act empowers the Director of Physical Planning to advise the

Commissioner of Lands on appropriate uses of land and land management. The Act

ensures that use and development of land and buildings is carried out in accordance

with the projected development plans of the area.

3.2.6 Local Government Act (Cap 265)

The Local Government Act (Cap 265) provides for local councils to establish and

maintain sewage and drainage systems. It has also provisions for the construction of

water supply systems and measures for the prevention of pollution in urban areas. The

project site falls within Mombasa Municipality and would hence be governed by the

provisions of this act.

3.2.7 Kenya Ports Authority (KPA) Act

Through the Kenya Ports Authority (KPA) Act, KPA has the responsibility for controlling

oil pollution in the Kenyan territorial waters, which include all inshore waters and those

extending up to 160km offshore. In fulfillment of this obligation, the KPA together with

the Oil Spill Mutual Aid Group OSMAG has developed a National Oil Spill Response

Contingency Plan.

26

3.2.8 Kenya Maritime Authority Act

Kenya Maritime Authority is charged with the responsibility of regulating, coordinating

and overseeing maritime affairs in the country. In fulfilling this mandate KMA is expected

to:

• Advise the government on the development of international maritime conventions,

treaties and agreements as well as their codification into the laws of Kenya;

• Conduct and liaise with other stakeholders in doing research, investigations and

surveys relating to maritime affairs;

• Develop and maintain the national oil spill response plan in coastal and inland

waterways in liaison with players in the oil industry;

• Serve as coordinators of search and rescue operations in liaison with KPA, Kenya

Navy and other relevant bodies;

• Ensure sustainable exploitation of marine resources and rapid response to marine

calamities;

KMA therefore provides a forum for which the various players involved in maritime affairs

develop maritime policies and integrate these policies into the national development

plan.

Further, KPA policy on environmental issues is governed by the provisions of The

International Convention for the Prevention of Pollution from Ships, 1973 (MARPOL

73/78) to which Kenya ascribes. This is the most important instrument for preventing

pollution from arising from marine transportation. It was adopted in 1973 and modified by

the Protocol of 1978 relating thereto, hence MARPOL 73/78. It consists of five Annexes

as follows:

Annex I: Oil - Ships are prohibited to discharge oil or oily water, such as dirty ballast

water and oily bilge water containing more than 15 ppm of oil, within 12 miles of land.

Other conditions apply to discharges outside 12 mile limits.

Annex II: Noxious Liquid Substances in Bulk - Chemicals are evaluated for the

environmental hazard they may cause if discharged into the sea (Categories A,B,C and

D). Discharge into the sea of the most harmful chemicals (Category A) is prohibited and

tank washings and other residues of less harmful substances (Categories B, C and D)

27

may only be discharged under certain conditions, e.g., total quantity, distance from the

shore, depth of water, prescribed depending on the hazards. There are substances, e.g.,

water, wine, acetone, ethyl alcohol, for which no restrictions apply.

Annex III: Harmful substances in packaged form - this is principally oriented towards

prevention of pollution by regulating packaging, marking and labeling and stowage.

Annex IV: Sewage - It is prohibited to discharge ship-generated sewage unless it is

treated with an approved sewage treatment plant or at a certain distance from land.

Annex V Garbage: - Garbage produced on board a ship, food waste, packaging, etc.

must be kept on board and discharged either ashore or into the sea under certain

conditions, such as the distance from land. Discharge of all plastics is prohibited.

Maritime operations are also regulated by London Convention, 1972 which prohibits

dumping of garbage at sea.

28

4.0 PROJECT DESCRIPTION

4.1 Introduction Kenya Ports Authority (KPA) has embarked on a Port Expansion and Modernization

Project whose objective is to enable the port cope with a rapid increase of national and

international container throughput. As part of this project a new container terminal will be

designed to accommodate more container cargo and post-panamax vessels which are

bigger than the ones the port is currently receiving. This requires KPA to improve

existing waterside facilities by dredging the access channel, the turning and anchorage

basins at the proposed Kipevu West Container Terminal as well as the associated

navigation aids. Also incorporated into this project is maintenance dredging at the

existing berths 1-19.

These areas including the proposed areas for dumping of dredged material are shown in

Figure 4.1 below:

Figure 4.1: Location of the dredging and dumping areas

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4.2 Preliminary Survey In order to obtain necessary information on natural conditions for detailed design and

simulation works, Hydraulic Survey, Geotechnical Investigation and Sediment Quality

Analysis were carried out in and around the planned dredging and dumping areas.

Scope and results of the surveys are briefly described in the following sections. Full

results are available in the separate Survey Reports.

4.2.1 Hydraulic survey

This survey was carried out by Southern Engineering Co Ltd from January 2008 to

March 2008. It consisted of three (3) items and their purposes are shown in Table 4.1

Table 4.1 Item and Purpose of Hydraulic Survey

Survey Item Purpose 1. Bathymetric Survey To set up seabed elevation in simulation works.

To set up dredging dimensions. To calculate required dredging volumes

2. Seismic Survey To verify existence of hard material (rock) layer in dredging area

4. Tide, Current and Suspended Solid (SS) Measurement

To set up hydraulic conditions in simulation works To decide dredging dimensions To assess construction effieciency

The above surveys were carried out in the areas shown in Figure 4.2.

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Figure 4.2: Hydraulic survey

Key results of the survey are shown in Table 4.2 and Figures 4.3 and 4.4.

Table 4. 2: Key Survey Results

Survey Item Primary Results

1. Bathymetric Survey - Seabed level in entire survey area was obtained. See Figure 4.3 - Very deep areas (CDL-40 to 60m) at port entrance and narrow bend section were surveyed. - Two small wrecks were found outside dredging area. - No fluid mud was found by means of dual frequency echo sounding.

2. Seismic Survey - Hard material was found in dredging area outside port entrance but not found inside port entrance.

3. Tide, Current and Suspended Solid (SS) Measurement

- Observed high and low tides in spring tide were about CDL+3.6 and +0.3, respectively. - Current max speed ranges about from 40 to 120 m/sec. Highest current speed was observed at port entrance station at 110 m/sec. See Figure 4.4. - SS concentrations in surface and middle layers range from 5 to 30 mg/l. SS concentrations in bottom layer inside port entrance reach about 120 mg/l caused by re-suspension of fine particles on seabed.

31

4.2.2 Geotechnical Investigation

This Investigation was carried out by Foundation Pilling Limited from February 2008 to

March 2008. The Geotechnical Investigation consists of three (3) items and their

purposes are shown in Table 4.3

Table 4. 3: Item and Purpose of Geotechnical Investigation

Investigation Item Purpose

1. Boring and Laboratory Analysis

To verify results of seismic survey. To obtain characteristics of seabed materials to be dredged.

2. Jet Boring

To complement results of boring survey.

3. Seabed Material Sampling

To set up particle size distribution of seabed material in simulation works.

The above investigations were carried out in the areas shown in Figure 4.5

Figure 4. 3: Results of Bathymetric Survey

Figure 4. 4: Results of Current Measurement

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Figure 4. 5: Area of Investigation

Key investigation results are shown in Table 4.4 below:

Table 4. 4: Primary Investigation Results

Investigation Item Primary Results 1. Boring & Laboratory Analysis

- Hard materials (coble and gravel) were found in the dredging area at Boring No. 1- 6 and 7. See Figure 4.6 and Attachment 1. - Soft materials (silt) were found in the dredging area at Boring No. 8, 9 and 10.

2. Jet Boring

- Seabed materials inside port entrance are very soft and cohesive.

3. Seabed Material Sampling

- Seabed materials outside port entrance are composed of hard coral, gravel and sand, while seabed materials inside port entrance are composed of very soft fine silt.

See Figure 4.7

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Figure 4. 6: Results of seabed boring

Figure 4. 7: Results of seabed material sampling

34

4.2.3 Sediment quality analysis

This exercise was carried out by NEMA certified SGS Kenya Limited and the

Department of Mines and Geology. The item and purpose of Sediment Quality Analysis

are shown in Table 4.5.

Table 4. 5: Item and Purpose of Sediment Quality Analysis

Analysis Item Purpose Sampling and concentration analysis of heavy metals (Hg, As, Cd)

To verify sediment quality to accept disposal of dredged materials at the designated offshore dumping area, comparing with the permissible Concentration levels presented in World Bank technical paper no 126, 1990. The permissible levels of Hg, As, Cd are 1.6, 85, 7.5 mg/kg, respectively.

As a result of laboratory analysis, no sample exceeded the permissible concentration

levels presented. However, as a common practice, a dredging contractor shall carry out

re-sampling and analysis in their Pre-dredging Survey and Environmental Monitoring

Survey.

4.2.4 Conclusion on Preliminary Survey In summary the preliminary survey came out with the following key findings

♦ Maximum and average current speeds at bending areas along the existing channel

reaches at about 110 and 65 cm/sec, respectively.

♦ Seabed materials to be dredged can be categorized into two (2) types, i.e. soft

materials (silt, N value=1) and hard materials (cobble and gravel, N value=refused)

♦ No significant contamination of seabed materials by heavy metals, such as cadmium,

arsenic, mercury, has been detected in the planned dredging areas.

4.3 Detailed Design Detailed design of the capital dredging, maintenance dredging and ancillary works

(navigation aids and tide gage installation) were carried out. Primary results of the

detailed design are as follows.

35

4.3.1 Capital dredging

As for the access channel, original alignment of center line, depth of CDL-15m and width

of 300m were confirmed to be acceptable in terms of safe channel operation by ship

operation simulation. The turning basin and anchorage were designed to be dredged

down to CDL-15 and CDL-12m having width of 500m and 375m, respectively.

4.3.2 Maintenance dredging

Maintenance dredging of the basins in front of the existing berths No. 1 to No. 19 and

Mbaraki wharf were designed to be dredged down to the depths which keep existing

berth structures stable, i.e. CDL-10m to CDL-11m.

4.3.3 Ancillary works Lighting buoys, leading lights and a tide gage station were designed. As a result of the

ship operation simulation, no installation and relocation of the lighting buoys in the

access channel was proposed. Eight (8) lighting buoys are designed to be installed at

corners of the planned anchorage and turning basin. Improvement of all existing leading

lights, i.e. raising height and light intensity, were also designed. A tide gauge station,

which continuously measures tide level in an observation well by a float, was designed

as a permanent facility.

4.4 Numerical Simulation In order to verify the technical and environmental conditions which form the basis of this

detailed design works, numerical simulations on four (4) subjects were carried out as

described below.

4.4.1 Ship operation simulation Critical conditions which make handling of the post-panamax vessels difficult were

revealed in this simulation. They are caused by tide, current, wind and other marine

traffic. Analyzing the results of simulation together with the comments given by KPA

pilots, a ship operation manual was prepared.

36

4.4.2 Siltation simulation As a result of simulation, possible siltation thickness and volume in the turning basin

area were estimated. They are 15.7 cm per year and 115,000 m3 per year, respectively.

These figures imply that capital dredging of the turning basin with over dredging of 0.5 m

will be followed by maintenance dredging after three (3) years. It is noted that in some

location, such as corner and edge of the dredging area where stagnant water likely

occur, the siltation thickness per year may be greater than the above figure, i.e. two fold.

Since seabed materials in the port entrance area consist mainly of coral cobble and

gravel, no significant siltation was estimated at the access channel dredging area.

4.4.3 Turbid water dispersion simulation In consideration of most possible dredging and dumping methods, potential area and

concentration level of turbid water dispersion at dredging and dumping areas were

predicted. In the anchorage and turning basin dredging area, turbidity of vicinal waters

will be increased during the dredging operation. However, no turbid water will reach

coral reef beyond the port entrance. In and around the offshore dumping area, which is

located about four (4) km away from the coral reef; dense turbid water will disperse in

the bottom layer along the coral reef. However, no area indicating more than 10 mg/L

increase in turbidity reaches -50 m isobar which is known as the deepest outer fringe of

the existing coral reef. Since dumping is done from the bottom door of transport vessels

at the area having -150 m in depth, no significant increase in water turbidity is expected

in the surface layer.

4.4.4 Wave penetration simulation This simulation was carried out to determine the impact of access channel dredging on

the wave conditions in and around the port entrance. The simulation results revealed

that change of wave height before and after the dredging is small, less 10%. Therefore,

impact of the dredging on local wave climate will be negligible.

4.5 Quantity Calculation Quantity of capital dredging, maintenance dredging and ancillary works was calculated

as shown in the Tables 4.6 and 4.7. It is noted that all quantities in the tables are

minimum quantities; no extra and over dredging volume is included.

37

Table 4. 6: Capital Dredging

Dredge Area Quantity

(m3)

Hardness of

Materials

Dredging Dimensions

Depth (m) Width (m) Slope

1. Access Channel 612,325

C-1 367,995 Hard -15 300 1:1

C-2 72,370 Hard -15 300 1:1

C-3 10,450 Hard -15 300 1:1

C-4 1,660 Soft -15 300 1:4

C-5 143,095 Soft -15 300 1:4

C-6 16,755 Soft -15 300 1:4

2. Turning Basin 4,534,405

C-7 2,657,155 Soft -15 500 1:4

C-8 1,291,950 Soft -15 500 1:4

C-9 585,300 Soft -15 500 1:4

3. Anchorage

Basin 7,403,841

C-101-1 2.903,592 Soft -12 375 1:4

C-101-2 4,500279 Soft -12 375 1:4

Total 12,550,571

Table 4. 7: Maintenance Dredging

Dredge Area Quantity

(m3)

Hardness of

Materials

Dredging Dimensions

Depth (m) Width (m) Slope

1. Basins in front

of existing berths

272,704

M-1 141,655 Soft -10 150 1:4

M-2 41,285 Soft -10 150 1:4

M-3 60,063 Soft -10 150 1:4

M-4 21,793 Soft -10/ -10.36 150 1:4

M-5 7,908 Soft -11 150 1:4

The projected total dredge volumes were therefore found to be as follows:

Access Channel (C1 – C6) - 0.6 million m3

Turning basin (C7 – C9) - 4.5 million m3

Anchorage Basin (C 10) - 2.9 million m3

Maintenance dredging (M1 – M4) -0.2 million m3

A list of the ancillary works to be accomplished is presented in Table 4.8.

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Table 4. 8: Ancillary Works

Item Quantity

(Number)

Remarks

1.Navigation Aids

Lighting Buoy 8 Fabrication and installation of new

buoys, including mooring anchor

Leading Light 13 Replacement of lights

2. Tide Gauge

Tide Gauge Station 1 Construction of Tide Gauge Station,

including recording equipment and

analysis soft ware.

4.6 Dredging Plan

There are basically three mechanisms by which dredging may be accomplished:

(1) Suction dredging: This involves removal of light, loose materials. This method is used

mainly for maintenance dredging projects.

(2) Mechanical dredging: Removal of loose or hard compacted materials either for

maintenance or new work projects.

(3) A combination of suction and mechanical dredging: Involves removal of loose or hard

compacted materials by cutter heads, either for maintenance or new work projects.

Factors that influence the choice of a dredging method and plant include:

♦ Characteristics of the dredging location and quantities to be dredged, considering

future needs;

♦ Pertinent social, environmental, and legal factors.

4.7 Dredging Equipment

4.7.1 Dredging of turning and anchorage basins Sediment quality analysis undertaken during the EIA Study indicated that dredged

material at the turning basin (C-7,8,9) and anchorage basin (C-10-12) navigation

channel would be soft and silty. Due to this and taking into account the wide area and

large volume of material to be dredged, the Trailing Suction Hoppe Dredger was

considered to be the most suitable (Figure 4.8).

39

Figure 8: Trailing Suction Hopper Dredger

Hopper dredges are self-propelled seagoing ships of 180 to 550 ft in length, equipped

with propulsion machinery, sediment containers (hoppers), dredge pumps, and other

special equipment required to perform their essential function of removing material from

a channel bottom or ocean bed. Dredged material is raised by dredge pumps through

drag arms connected to drags in contact with the channel bottom and discharged into

hoppers built in the vessel.

Dredging is accomplished by progressive traverses over the area to be dredged. Suction

pipes (drag-arms) are hinged on each side of the vessel with the intake (drag) extending

downward toward the stern of the vessel. The drag is moved along the channel bottom

as the vessel moves forward. The dredged material is sucked up the pipe and deposited

and stored in the hoppers of the vessel. Once fully loaded, hopper dredges move to the

disposal site to unload before resuming dredging.

Advantages of Hopper Dredges Because of the hopper dredge’s design and method of operation, it has the following

advantages over other types of dredgers for many types of projects:

♦ It can work effectively, safely, and economically in rough, open water under its own power.

♦ Its operation has minimal interfere on port traffic.

♦ Its method of operation produces usable channel improvement almost as soon

as work begins. A hopper dredge usually traverses the entire length of the

40

channel, excavating a shallow cut during each passage and increasing channel

depth as work progresses.

Limitations:

The hopper dredge is a seagoing self-propelled vessel designed for specific dredging

projects. The following limitations are associated with this dredge:

♦ Its deep draft precludes use in shallow waters, including barge channels

♦ It cannot dredge continuously. The normal operation involves loading,

transporting material to the dump site, unloading, and returning to the dredging

site.

♦ Consolidated clay material cannot be economically dredged with the hopper

dredge.

4.7.2 Dredging of Access Channel and Navigation Channel at inner port Hard materials in access channel (C-1, C2 and C3) and at navigation channel at inner

port (C4 – C6) will be dredged by a Grab Dredger (Figure 4.9). Grab Dredgers are non-

propelled barges equipped with a mechanical grab hanged by a crane arm. The grab is

dropped into the water to dredge bed materials. The dredged materials are loaded on a

transport barge mounted next to the dredger.

Figure 4. 9: Grab Dredger

41

The transport barges with full load are transported by a tugboat to designated dumping

location to discharge the loaded materials. Empty barges go back to the dredging site to

load next dredged materials.

Advantages: The grab dredger has the following advantages:

• Replacing the grab, any materials (silt, sand, rock) can be dredged.

• Accurate dredging work is possible.

• Dredging work in shallow area is possible.

• Using a special grab and surrounding frame with protection curtain, contaminated

materials can be dredged and transported to the designated dumping location with

minimum environmental impacts.

Limitations: The limitations on grab dredgers are as follows:

• Hindrance to existing operations due to stretched wires to keep the positions of the

dredger.

• Dredging of wide area is not efficient in general.

4.7.3 Maintenance dredging

Soft materials in front of the existing berths (M-1,2,3,4,5) will be dredged by a Grab

Dredger.

42

5. THE PHYSICAL OCEANOGRAPHIC ENVIRONMENT AT KILINDINI

HARBOUR

5.1 Introduction Estuaries contain important harbors, ports and navigational channels. Many of the

world’s seaports are located on estuaries and ready access requires maintenance of

navigation channels. Estuaries are effective traps for sediments. A significant feature of

most estuaries is a zone of high-suspended sediment concentration near the head of the

estuary, turbidity maximum zone. This zone often contains high concentrations of

contaminants to which are added pollutants from effluent discharges (Martin, 1999). The

accumulation of sediments in harbors and navigational channels makes it necessary to

carry out dredging works to ensure safe navigation for large ships.

Estuaries often have complex coastline and bathymetric variations that give rise to

strong spatial variations in the tidal currents and marked asymmetry between ebb and

flood flows (Shetye, 1992). This in turn leads to effective tidal dispersion and exchange.

Understanding these mixing processes is of critical importance for effective

environmental management of these regions. Due to geometrical complexity of most

estuaries and embayment, both field observations and numerical models are needed to

understand the hydrodynamics.

Research on water circulation in estuarine systems is important because hydrodynamic

processes influence the sustainability of marine ecological systems. Knowledge on water

circulation is necessary for a better understanding of the biological, chemical and

physical processes taking place. Information on water circulation also determines the

interaction and therefore the linkage between coastal and marine ecosystems through

nutrients and material exchanges (e.g. Wolanski et al. 1980; Kjerfve et al. 1991). The

study of water circulation is also significant to environmentalists and land-use planners

interested in determining the impact of coastal development projects on marine

ecosystems. Thus, the description of coastal water circulation and exchange patterns in

estuaries is crucial to understanding the ecosystem dynamics.

Some previous studies have shown that most estuarine systems are characterized by

the occurrence of time velocity asymmetry in which the ebb tidal flow is much stronger

than the flood tidal flow (Furukawa, Wolanski, & Mueller, 1997; Kitheka et. al., 2003;

43

Wolanski, Jones, & Bunt, 1980). This situation results in a net seaward-directed residual

flow that is crucial in determining the net flux of materials (including sediments) out of the

system.

Knowledge of the hydrodynamics of estuaries is necessary for a better understanding of

how sediments are transported and dispersed within the system and how the channel is

flushed through exchange with offshore waters. The fate and transport of materials in the

system are strongly related to the hydrodynamic conditions.

Among a wide range of factors influencing sediment transport in estuaries, tidal range

and current speed are the most important (Althausen and Kjerfve, 1992; Lindsay et al.,

1996). It is often argued that in estuarine systems with tidal asymmetry, the net sediment

flux follows pattern of the dominant tidal current. If the system is ebb dominant, there will

possibly be ebb dominance in the fluxes of suspended sediment (Linsay et al., 1996).

Wolanski et al., (1998), Mazda et al., (1995) found that the net sediment transport to be

principally controlled by the asymmetry between flood and ebb tides.

This report presents the hydrodynamic characteristics of Kilindini harbor, Mombasa.

Water levels are available for one year period. Time series of current velocity and water

temperature data was observed for a period of 30 days. We investigate the factor(s)

responsible for water movements, circulation patterns and establish if there is tidal

asymmetry in the harbor.

5.2 Study area 5.2.1 Meteorological conditions The area experiences a tropical climate characterised by the monsoon seasons. In

general the climate is hot and humid throughout the year. The shifting monsoons result

in two distinct dry seasons and two rainy seasons. The South-East monsoon (SEM)

related to the long rains, occurs from April to October and the North-East Monsoon

(NEM), which causes the short rains, occurs from November to March. The monsoon

transitional stages occur in late October and mid April respectively. The maximum

rainfall during the long rains experienced in May while that due to short-rains is

experienced in November. The total annual rainfall in Mombasa ranges from 1000 to

1500 mm.

44

The annual mean air temperature is 27o C. The seasonal variations in air temperature

are not large at Kilindini harbour. The difference between the lowest and highest air

temperature is about 10o C. This is typical of equatorial regions where there are no large

seasonal variations in solar radiation influx. The highest air temperatures recorded in the

period December-March, are usually associated with the influx of warm air mass

associated with the NEM blowing from the Arabian Peninsular.

0

1

2

3

4

5

6

7

8

9

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Win

d s

pe

ed

(m

/s)

Figure 5.1: Seasonal variations of the average wind speed during the northeast and southeast monsoons

On the other hand, the lowest air temperatures (22o C in June-August period is usually

related to the influx of the cool air mass from the Southern Africa and Southern Indian

Ocean region. As compared to seasonal air temperature variations, there are also

diurnal temperature variations, which are principally related to the net heating by the

incoming short-wave radiation during the day and net cooling due to long-wave back

radiation at night. Water temperature variations within the harbour essentially show

diurnal features, which are similar to those of air temperature. The rates of open water

evaporation are 6mm per day during the dry season and drops to less than 2 mm per

day during the wet season. Evaporation tends to be high in the period between

December and March during the NEM and also in the period between August and

October during the SEM. Relative humidity averages 80%. (Meteorological Dept. 2000).

45

The surface winds in the coastal region of Kenya are dominated by the two distinct

monsoons. From April to November, the winds blow from the southwest direction,

reaching peak velocities in July and August. They then gradually reduce in strength to a

minimum in November when they reverse to north-easterly direction. The next reversal

occurs in March/April at the onset of the southwest monsoons and November/December

at the onset of the northeast monsoon. The winds of the NEM are markedly influenced

by a land-sea breeze. They blow at an average wind velocity of about 6 ms-1. The winds

of the SEM are stronger and to a lesser degree influenced by the land-sea breeze. They

blow mostly to the North with an average velocity of 7.5 ms-1.

5.2.2 Coastal Currents The most important current along the Kenyan coastline is the EACC, which has a net

northward flow. The speed of this current varies between 0.25 and 1 ms-1, being fastest

during the SEM, and lowest during the NEM. During the NEM, along Kenya, the EACC

converges with a weaker southward flowing Somali current. The convergence zone of

these currents constitutes the root of the Equatorial Counter Current. During the SEM, a

large portion of the Equatorial Current is moved northward via the powerful Somali

Current along Kenya and Somalia and is absorbed eastward by the southwest monsoon

current (Duing and Schott, 1978).

The Equatorial Counter Current is present south of the equator between 2 and 5 so and

is quite strong in the NEM period. The northward flowing Somali Current is well

developed in June and is stronger in July. The Somali current is still strong in August but

its southern extent is reduced. In September, the current is prominent only beyond 5 on.

Intense up welling occurs during the SEM season along the northern part of Kenyan

coastline and Somali area. As a result of this up welling, cold surface water is brought to

the nearshore surface layers, which spreads over extensive areas of the Arabian sea.

Thus the local climate and biological productivity are much controlled by oceanic

processes (Benny, 2002).

Thus, the Western Indian Ocean currents show spatial and temporal variations. Among

the currents, the Somali Currents exhibits more dramatic seasonal variation than any

other current in the region. The Somali Current is notable for its high speed of up to 200

cms-1.

46

5.3 Data Collection and Analysis 5.3.1 Measurements of water elevation We have utilized one year time series of sea level observations from a tide gauge

installed at Liwatoni jetty in Kilindini harbor, Mombasa (Figure 5.2). The Mombasa tide

gauge being managed by Kenya Marine & Fisheries Research Institute (KMFRI) is a

principal station on the Global Sea Level Observing System (GLOSS) network. It

measures sea level every 15 minutes interval and transmits a signal every hour to

University of Hawaii Sea Level Centre for inclusion in the global sea level database.

Data from this station is for monitoring climate change induced sea level rise and also for

detecting extreme oceanic events such as storm surges and tsunamis.

The station is equipped with 3 sensors consisting of a Float, Radar and Pressure sensor.

The float sensor is not operational at the moment. The additional sensors are for

redundancy checks in the system. Figure 2 below is a photo of the Mombasa tide station.

5.3.2 Measurements of current velocities and temperature During the period, one Aanderaa Recording Current Meters (RCM) was moored near

Liwatoni Jetty in Kilindini harbour in the middle of the channel about 5m below the water

surface during LWS. The instrument was programmed to measure and record current

speed and directions at 10 minutes interval. The current velocity sensor has a velocity

range of 0 to 3 ms-1 and a precision of ±2 cms-1. The magnetic compass Hall Effect type

of the current direction sensor has a precision of ±1.5o. Table shows the record span of

available field data at each of the sampling sites.

The RCM is also equipped with an additional sensor for measuring and recording water

temperature. The temperature sensor has a precision of ±0.1o C.

5.3.3 Decomposition of tidal currents Tidal current velocities measured by the Aanderaa Recording Current Meter (RCM-9)

were decomposed in order to determine the horizontal velocity components within the

main channel. The main direction of flow was determined by plotting current velocities

against their respective directions. This was also used to determine the dominant current

47

velocities during the period of measurements. The along channel velocity component (u)

was determined from the current velocity record as

=

180cos

απUu (1)

The cross channel velocity component (v) was determined by using the equation

=

180sin

απUv (2)

Where U is the current speed record and α is the direction angle measured in degrees.

48

Figure 5.2: KMFRI GLOSS Tide Gauge at Liwatoni jetty in Kilindini harbour, Mombasa

5.3.4 Harmonic analysis Harmonic analysis is a mathematical method of extracting sinusoidal components of

specific frequencies from e.g. a water level record. In this case, it is based on the

“method of least squares”. Instead of fitting a straight line to the data by varying its slope

and intercept, a set of cosine (or sine) curves with given frequencies ω are fitted by

varying amplitudes and phases, minimizing the sum of deviations from the original curve.

Given a time series Z (t) of data points, its tidal part can be expressed as a combination

of sine and cosine functions (cf. Shureman, 1941; Dronkers, 1964).

49

∑ ∑+=k k

kkkk tbtatZ )cos()sin()( ωω (3)

The value of ak and bk can be calculated for the given frequencies, ωk by minimizing the

sum of squares of the differences between the assumed function and the given time

series Zn.

Least square fit requires that the following function is minimized

2

1

)cos()sin(),( ∑ ∑ ∑=

+−=

N

n k k

nkknkknkk tbtazbaf ωω (4)

This requirement is satisfied by

0=∂

∂

ia

f i = 1,…,k (5)

and

0=∂

∂

ib

f i = 1,…,k (6)

Where

0)cos()sin()cos(21

=

−−−=

∂

∂∑ ∑ ∑

=

N

n k k

nkknkknni

i

tbtazta

fωωω (7)

and

0)cos()sin()sin(21

=

−−−=

∂

∂∑ ∑ ∑

=

N

n k k

nkknkknni

i

tbtaztb

fωωω (8)

The above equations can be rewritten as

∑ ∑ ∑∑ ∑= ==

=+k

N

n

N

n

ninnkniknk

k

N

n

nkk tZttbtta1 11

)sin()sin()sin()cos()sin( ωωωωω (9)

50

∑ ∑ ∑∑ ∑= ==

=+k

N

n

N

n

ninnkniknk

k

N

n

nkk tZttbtta1 11

)cos()sin()cos()cos()cos( ωωωωω (10)

This can be simplified by introducing the notation

)cos( niin tC ω= , )sin( nkkn tS ω= (11)

∑ ∑ ∑=+k k n

innkninkknknk SZSSbCSa (12)

∑ ∑ ∑=+k k n

innkninkknknk SZSCbCCa (13)

Which gives a system of 2k equations with 2k unknowns; ai through ak and bi through bk.

Table 5.1: Major tidal constituents

Tidal Constituent

Symbol Period (hours)

Diurnal Components: Principal lunar diurnal Principal solar diurnal Luni solar diurnal

O1 P1 K1

25.82 24.07 23.93

Semi-diurnal Components: Principal lunar Principal solar Luni-solar Larger lunar elliptic

M2 S2 K2 N2

12.42 12.00 11.97 12.66

Shallow water Components:

M4 M6 S4 2MS2 MS4 2MS6

6.21 4.14 6.00 11.61 6.10 4.09

Long Period Component: Lunar fortnightly

Mf

327.86

51

5.3.5 Spectral analysis Spectral analysis of time series is one of the most commonly used data analysis

techniques in Physical Sciences. The analysis is based on a representation for a time

series in terms of a linear combination of sinusoids with different frequencies and

amplitudes. This type of a representation is called a Fourier transformation.

A spectral plot is a graphical technique for examining cyclic structure of time series in the

frequency domain. It is a smoothed Fourier transformation of the auto covariance

function. Trends should be removed from the time series before applying the spectral

plot. Trends are typically removed by differencing the series or by fitting a straight line

(or some other polynomial curve) and applying the spectral analysis to the residuals.

Spectral plots are often used to find a starting value for the frequency,ω in the sinusoidal

model.

To determine the "dominant" frequencies in the time series, we define the power spectral

density as

2

)(2

)( fYT

fG = (14)

where T is the length of the time series, and Y(f) is a discrete function. This is the

continuous representation of the power spectral density, and gives an estimate of the

"power" in the signal y (t) at a particular frequency f. The discrete representation of the

power spectral density is

2)(

2)( fY

N

tfG

∆− (15)

N is the number of measurements. Analysis of the power spectral density G (f) allows us

to investigate the dominant frequencies in a signal, as it is the dominant frequencies that

are likely to be important to the physical process. One technique to estimate the power

spectrum, is to use a periodogram estimate which is defined at N/2+1 frequencies as

2

2

1)( oo F

NfP = (16)

52

( )22

2

1)( kNkk FF

NfP −+= 1)2/(,...,2,1 −= Nk (17)

2

22

1)( Nc F

NfP = (18)

It is sometimes of interest to investigate the joint structure of two series. That is the

dependence of either series on the other. We are only able to observe relationships at

the same frequency in both series. We define the cross-spectrum as

[ ])()(2

)( * wYwYT

wG yxxy = (19)

The "*" refers to the complex conjugate of the function.

Unlike the power spectrum, the cross-spectrum is complex valued as it contains

amplitude and phase information. The real part of the cross-spectrum is known as the

coincident spectrum (or co-spectrum), and the complex part of the cross-spectrum is

known as the quadrature spectrum (or quad-spectrum). From the cross-spectrum, we

are able to estimate the amplitude and phase relationship between the signals. The

amplitude relationship is quantified through the coherency squared, calculated as

)()(

)()(

2

2

wGwG

wGwS

yx

xy

xy = (20)

A coherency squared value of unity indicates complete dependence of one signal on

another, whereas a coherency squared value of zero refers to no dependence of one

signal on another. Two signals can only be coherent at the same frequency.

5.4 Results and Discussion 5.4.1 Tides Time series data of water levels and current velocities was subjected to harmonic and

spectral analysis using T_Tide software (Pawlowicz et. al., 2002). The water level

variations at Liwatoni are sinusoidal with two unequal peaks daily. The results from

harmonic analysis are shown in Table 5.3 and Figure 5.3.

53

The semi-diurnal constituents account for over 80% of the water level variations of which

M2 alone accounts for 47%. The amplitudes of the harmonic constituents compare well

with those obtained by Pugh (1979) by analyzing one year of data collected in Kilindini

harbour, Mombasa.

Table 5.2: The classification of the tides based on F-ratio scale

Form number

F = (K1+O1)/(M2+S2)

Type of tide

0 < F < 0.25

0.25 < F < 1.5

1.5 < F < 3.0

F > 3.0

Purely semi-diurnal

Mixed, mainly semi-diurnal

Mixed, mainly diurnal

Purely diurnal

A form number, F, has been defined as the ratio of the sum of amplitudes of diurnal tidal

species over semi diurnal species. According to Defant (1958), a simplified definition for

F, F = (k1+O1)/(M2+S2), can be used to characterize tidal types. If F is less than 0.25, the

tide is referred to as semi-diurnal, and if F is greater than 3.0, the tide is diurnal. Value of

F between 0.25 and 3.0 are considered as mixed tides (see Table 5.2). The form

number at Liwatoni station in Kilindini harbor is 0.19 indicating that the tides are typically

semi-diurnal. The spring tidal range is 3.12 m and neap range is 1.04 (Table 5.5).

The computed phase age indicates that spring tides lag local passage of full or new

moon by 41 hours, whereas the inequality phase relationship, 31o indicates that water

level inequalities occur in both high and low water (see Table 5.5). Figure 5.9 shows

observed sea levels at Liwatoni station also indicating the semi-diurnal inequality with

successive high water and successive low waters having different heights.

54

Table 5.3: Results of harmonic analysis of water levels in Liwatoni

Constituent Period (h) Liwatoni

Amplitude (m) Phase (o)

Pugh

Amplitude (m) Phase (o)

M2

K1

S2

O1

P1

N2

Mf

K2

2SM2

M4

MS4

S4

M6

2MS6

12.42

23.93

12.00

25.82

24.07

12.66

327.8

11.97

11.61

6.21

6.10

6.00

4.14

4.09

1.042 67

156

0.520 114

0.086 37

0.115 176

0.191 27

0.078 356

0.139 203

0.008 18

0.013 216

0.037 211

0.029 196

0.012 108

0.026 232

1.055 27

356

0.521 66

0.113 0

0.055 354

6

- -

0.139 65

- -

0.012 137

0.004 191

- -

0.011 140

- -

The residuals are small (~20 cm) for both stations as can be seen in Figure 5.3. They

could be due to local forcing by wind stress and air pressure fluctuations. This indicates

that meteorological forcing plays a minor role in the water level variations. In this case it

also indicates that tidal forcing exclusively causes water movements in the system.

Spectral analysis results for water levels and currents measurements are shown in

Figures 5.10 and 5.11. For both tides and currents, the semi-diurnal and diurnal energy

peaks are dominating the spectrum as shown by the two clear peaks. At periods below

10 hours, the spectrum becomes somewhat ragged, and the computed energy peaks

are probably not statistically significant.

55

01/01/07 04/01/07 07/01/07 10/01/07 01/01/08-2

-1

0

1

2

Wate

r Lev

el (m

)

01/01/07 04/01/07 07/01/07 10/01/07 01/01/08-2

-1

0

1

2

Wate

r Lev

el (m

)

01/01/07 04/01/07 07/01/07 10/01/07 01/01/08-2

-1

0

1

2

Wate

r Lev

el (m

)

Year

Figure 5.3: Time series water level variations at Mombasa tide gauge station for year 2007,

observed (blue), computed (red) and residual (magenta) values from harmonic analysis.

5.4.2 Currents Current measurements (Figure 5.4) showed that velocities in spring tides were generally

higher than in neap tides. Current meter data was analyzed in a manner similar to that

described above for tides. Harmonic analysis procedure was applied to the east-west (v)

and north-south (u) components of velocity. The results are presented in Table 5.4. and

Figures 5.5 and 5.6. The average flood and ebb flow directions at Liwatoni station are

separated by about 170° (280°) during flood and 110o during ebb (Figure 5.7). Maximum

spring velocities of 0.80 ms-1 and 0.50 ms-1 were observed during flood and ebb

respectively. A scatter plot of u (along channel) and v (cross channel) components of

velocities at Liwatoni station indicates that the flow is confined along the axis of the

channel during both spring and neap tides (Figure 5.8).

The currents in the channel indicate a relatively strong asymmetry with ebb currents being

stronger than flood currents. The ebb period is roughly 5.5 hours compared to a flood period

56

of about 7 hours, thus a slightly larger difference than that obtained from the tides at the

Liwatoni station (6.58 h Vs 6.04 h). This can be readily seen in Figure 5.9 where a

comparison is made between along channel components and water levels. The asymmetry

is not pronounced during neap, however. Higher velocities during ebb (0.8 ms-1) as

compared to flood (0.5 ms-1) are because of the different flow dynamics during filling of the

inter tidal area compared to during emptying (Wolanski, 1990). The asymmetric velocity is a

key parameter that reflects the topography of the harbor.

Although there is very little asymmetry in the tide, the current measurements in the

channel reveal an asymmetry of ebb-dominance, i.e. high ebb velocities and shorter ebb

periods. This asymmetry of ebb-dominance fits well with the conclusions concerning

topography by Shetye and Gouveia (1992). This features are similar to those in

Hinchinbrook channel (Wolanski et al., 1980) and in the North inlet which is a channel

surrounded by salt marshes (Kjerfve et al., 1991). Ebb-dominance has also been

observed in deep sub-tidal channels with mudflats e.g. the Wachapreague inlet (Boon

and Byrne, 1981). Non-linear friction effects in the mangrove swamps in the upper parts

of the harbor (Port Reitz creek area) could result in an asymmetry between the filling and

emptying of the mangrove swamps (e.g. Wolanski et al., 1980, Kitheka et al., 2003).

Comparison of water levels and current velocities indicate that water levels lead the

currents by an average of 3.45 hours (104o). Slack waters coincide with the times of high

and low water. The two variables are almost out of phase. Zero velocities in the channel

lag the occurrence of high water and low water by 0.6 hours and 0.2 hours respectively.

57

0 5 10 15 20 25 30-100

-80

-60

-40

-20

0

20

40

60

80

100

Velo

citie

s (

cm

s-1

)

Time (days)

Figure 5.4: Time series of current velocities at Liwatoni station

Table 5.4: Results of harmonic analysis of current velocities in Kilindini harbour

Constitue

nt

Period

(h)

U-Component

Amplitude (cm) Phase (o)

V-Component

Amplitude (cm) Phase

(o)

M2

K1

S2

O1

P1

N2

Mf

K2

2SM2

12.42

23.93

12.00

25.82

24.07

12.66

327.8

11.97

11.61

30.01 341

14

16.15 44

4.73 58

3.34 27

2.44 133

5.10 81

1.23 173

0.74 172

8.43 117

1.61 167

5.04 119

0.50 6

1.36 141

0.81 96

2.42 81

2.63 149

0.09 15

58

M4

MS4

S4

M6

2MS6

6.21

6.10

6.00

4.14

4.09

7.03 150

7.02 170

0.89 106

1.35 30

1.83 19

2.47 19

2.59 57

0.44 122

0.52 143

0.93 99

0 5 10 15 20 25 30-100

0

100

Velo

citie

s (

cm

s-1

)

0 5 10 15 20 25 30-100

0

100

Velo

citie

s (

cm

s-1

)

0 5 10 15 20 25 30-100

0

100

Velo

citie

s (

cm

s-1

)

Time (days)

(a)

(b)

(c)

Figure 5.5: Time series of (a) observed (b) computed and (c) residual for u-velocity components

at Liwatoni station from harmonic analysis results

59

0 5 10 15 20 25 30-100

0

100

Ve

locitie

s (

cm

s-1

)

0 5 10 15 20 25 30-100

0

100

Ve

locitie

s (

cm

s-1

)

0 5 10 15 20 25 30-100

0

100

Ve

locitie

s (

cm

s-1

)

Time (days)

(a)

(b)

(c)

Figure 5.6: Time series of (a) observed (b) computed) and (c) residual for v-velocity components

at Liwatoni station from harmonic analysis results

60

0 50 100 150 200 250 300 350 4000

10

20

30

40

50

60

70

80

Directions (degree)

Sp

ee

d (

cm

s-1

)

Figure 5.7: Observed current directions versus speeds at Liwatoni station

61

-80 -60 -40 -20 0 20 40 60-40

-30

-20

-10

0

10

20

u (cms-1)

v (

cm

s-1

)

Figure 5.8: Scatter plot of north-south (u) and east-west (v) current velocity components

62

0 10 20 30 40 50 60 70-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Time (hours)

Wa

ter

leve

l (m

) / V

elo

citie

s (

ms

-1)

Figure 5.9: Comparison of water levels (solid line) and current velocities (dotted line) at Liwatoni

station during spring tide.

Table 5.5: Tidal statistics, amplitudes and phases based on harmonic analysis

Parameter Formula Water Levels

Current

Velocitie

s

Form number (K1+O1)/(M2+S2) 0.19 0.21

Inequality Phase

Relationship

M2o-(K1

o+O1o)

-126o

268o

Phase age 0.98(S2o-M2

o) 46 25

Mean Range 2.2(M2) 2.29 0.66

Spring Range 2.0(M2+S2) 3.12 0.92

Neap Range 2.0(M2-S2) 1.04 0.28

Tropic Range 2.0(K1+O1) 0.58 0.20

Equatorial Range 2.0(K1-O1) 0.24 0.01

Diurnal Age 0.91(K1o-O1

o) 108o -40o

63

10-1

100

101

102

10-2

100

102

104

106

Period (hours)

Energ

y (

cm

2s

-2cph

-1)

(a)

Figure 5.10: Relative energy density spectrum for water levels Liwatoni station based on spectral

analysis.

64

10-1

100

101

102

102

103

104

105

106

107

108

Period (hours)

Energ

y (

cm

2s

-2cph

-1)

(b)

Figure 5.11 Relative energy density spectrum for current velocities at Liwatoni station based on

spectral analysis.

Harmonic analysis results of along channel (u) and cross channel (v) velocities using 14

tidal constituents are presented in Table 5.4. The results reveal that tidal currents

dominate the flow. Like the water levels, the semi-diurnal constituents account for 80%

of the total variability. M2 tidal constituent alone accounts for over 40%.

As in the case of tides, a form number can be defined to characterize tidal current types

where F is the ratio of the sum of the semi-major axes of tidal current ellipses for diurnal

over semidiurnal constituents. The computed F value is 0.21 thus indicating that the

currents in Kilindini harbor can be characterized as semi-diurnal (Table 5). The

maximum current speed at spring tide is estimated by (M2+S2) + (k1+O1), where the four

major harmonics are assumed to be in phase. The maximum current speed at neap

tides is estimated to be not less than (M2-S2) + (O1-K1) where M2 and S2, O1 and K1 are

assumed to be out of phase at the same time.

Comparison of the relative phase differences between the tides and tidal currents

reinforces the conclusion that the tides in Kilindini harbor are primarily standing waves.

The phase difference of M2 and K1 tidal currents at Liwatoni is 86o with the tides leading

65

the tidal current. For a pure standing wave, the phase of the tidal height leads the phase

of tidal current by exactly 90o.

5.4.3 Temperatures

The temperatures at Liwatoni station varied from 24.8 oC to 28.9 oC with a mean of

27.2oC (see Figure 5.12). A comparison between water levels and temperatures at the

tide gauge stations is shown in Figure 5.13. When the temperatures are related to the

time of the day, the maximum are observed between 12-13 h, corresponding to mid day

time when there is maximum solar radiation. Another peak appears at about 18 h,

corresponding to the high water time when warmer surface water from the ocean moves

into the harbor. There is no corresponding peak during the morning HW time, and this is

probably because at this time the ocean surface water has not been heated by solar

radiation.

0 5 10 15 20 25 3024.5

25

25.5

26

26.5

27

27.5

28

28.5

29

29.5

Time (Days)

Tem

pera

ture

(oC

)

Figure 5.12: Time series of water temperatures at Liwatoni station

66

0 10 20 30 40 5027

27.5

28

28.5

29

Time (Hours)

Tem

pera

ture

(oC

)

0 10 20 30 40 5027

27.5

28

28.5

29

Time (Hours)

Tem

pera

ture

(oC

)

0 10 20 30 40 50-2

-1

0

1

2

Time (Hours)

Wate

r Level (m

)

0 10 20 30 40 50-2

-1

0

1

2

Time (Hours)

Wate

r Level (m

)

(a) (b)

Figure 5.13: Comparison of water levels and temperatures at Liwatoni on (a) December 15, 2007

from midnight and (b) December 20, 2007 from midnight

At Liwatoni station, water temperature decreases during flood. The semi-diurnal

variability is clear during flood when more cool water enters into the harbor from the

deep Indian Ocean. Similar patterns of temperature variations have been observed in

the adjacent Tudor Creek (Odido, 1994). Lower water temperatures could also be

attributed to rapid tidal flushing and the effect of wind.

In general, the temperature variations in the harbor are dominated by the diurnal solar

heating and night cooling due to a combination of evaporation and long wave back

radiation. Temperature rise and fall patterns were asymmetric with rapid rises during the

day and gradual decreases in the evening and night.

5.5 Numerical Modeling of Hydrodynamics of Kilindini Harbor Due to the large spatial and temporal variability in water levels, current velocities and

salinity that exist, a large number of field observations must be carried out in order to

determine the hydrodynamic characteristics of estuaries. The costs associated with data

67

collection are usually quite high. A plausible solution out of this situation is the use of

numerical models as sophisticated techniques for interpolation of field data in both

special and temporal domains. These models however, must be compared against

available field data (i.e. calibration) and be shown to satisfactorily reproduce

independently the observed data sets (validation). Only then can the model be used as a

research tool for describing estuarine hydrodynamic characteristics. Rapid development

in computing hardware and software in recent years has provided researchers with

unprecedented opportunities to conduct estuarine hydrodynamic studies by use of

numerical models.

5.5.1 Additional Data Collection for Model Calibration and Validation In this study, we applied numerical simulations by means of a model that couples

hydrodynamics and diffusion of Suspended Sediment (SS) and sedimentation of

dumped soils. The model is a three-dimensional model, or “two-dimensional multi-layer

unsteady level model”

Figure 5.14: Stations at Kilindini harbor for monitoring tides, currents and suspended sediment concentrations as well as salinity in February to March 2008

Legend

Tide (4 points)

Current / Suspended Solid / Salinity (9 points)

No. 1No. 2No. 4No. 3No.5No.6No7No.9 No.8No.10

68

which has three layers vertically, employing Navier-Stokes’ equation of motion and the

equation of continuity of fluid water. See Appendix 1 for methodology of the dispersal

and settlement simulation model. The aim of the numerical modeling studies was to

provide detailed information on the hydrodynamic and sedimentological effects of the

proposed channel deepening and widening in support of studies relating to the

Environmental impact assessment (EIA). The key was developing a model which

accurately represented natural tidal conditions and hence sediment movement within the

study area. The model provided a means to assess the following:

• Prediction of the currents and hence how a sediment plume may behave;

• Prediction of sediment deposition during dredging and disposal.

In order to generate a better spatial resolution data for model calibration and validation,

additional stations were established at selected locations within Kilindini harbor to

monitor tides, currents and suspended solids as well as salinity (See Figure 5.14). These

observations were conducted in the period of February-March 2008.

5.6 Hydrodynamic and Sedimentary Implications of the Proposed Project After extensive validation against available observations, the model was used to predict

the effects of the proposed scheme on tidal flows, waves and sediment transport. Four

scenarios were examined during the numerical simulations:

Scenario 1: Offshore dumping in NE Monsoon season at designated Point in New

Container Terminal

Scenario 2: Offshore Dumping in SE Monsoon Season at Designated Point in New

Container Terminal

Scenario 3: Basin Dredging Operation in Turning Basin in front of New Container

Terminal + Temporally Dumping at New Container Terminal in NE Monsoon Season

Scenario 4: Basin Dredging Operation in Turning Basin in front of New Container

Terminal + Temporally Dumping at New Container Terminal in SE Monsoon Season

During the simulation field setting, the following cases were considered:

- Latest bathymetry measured in this study (see Figure 5.15)

- Current measured in this study

69

- Waterbed material characteristics Particle Size Distribution (PSD) obtained in this

study

- Wind described in Container Terminal EIA, and

- Water discharge from 2 rivers in Port Reitz described in Container Terminal EIA

The simulation period of the model continued for 10 days during spring tide duration, in

which turbidity levels had increased and reached constant values. The results of the

modeling exercise for the above scenarios are presented in Figures 5.16 – 5.22.

70

Figure 5.15: Result of two-dimensional bathymetric survey of Kilindini harbour

71

5.6.1 Turbidity Load Inputs

Based on the most possible construction schedule, Turbidity Loading Inputs were set as

follows.

Offshore Dumping

• Periodical dumping by Trailing Suction Dredger in every 5.8 hours

• Basin Dredging Operation by Trailing Suction Dredger

• Continuous discharge (overflow) from Trailing Suction Dredger for 0.5 hours in

every 4.8 hours

Temporally Dumping at New Container Terminal

• Periodical dumping by Transport Barge in every 6 hours

5.6.2 Dredging Period Because simulated results reached constant in 10 days as described above, the

estimated dredging period will not cause increase of turbidity as long as turbidity load

inputs are kept same. Total dredging period will be 11 to 17 Months. Dredging and

dumping location are shown in attached map.

5.6.3 Interpretation of simulation results

Scenario 1

Turbid water will disperse toward SW direction from dumping point; however 10 mg/l

contour will not reach to -50m depth contour, which is understood as deepest outer

fringe limit of Coral Reefs (Figures 5.16).

72

Figure 5.16: Turbid water dispersion simulation (surface and bottom layers) at offshore

dumping during NE Monsoon season (Jan – Apr).

73

Figure 5.17: Turbid water dispersion simulation (surface and bottom layers) at offshore

dumping during SE Monsoon season (Jul – Oct).

Scenario 2

Turbid water will disperse toward NE direction from dumping point. On the water surface

in southwest-end of the Mombasa Marine National Reserve, temporally turbidity

increase by 20 mg/L will be observed. However no increase higher than 10 mg/L will

reach to -50m depth counter in bottom layer, which is understood as deepest outer

fringe of Coral Reef (See Figure 5.17).

Scenario 3 and 4

No significant difference is shown between scenario 3 and 4. No turbid water will be

moved out beyond the port entrance. High turbidities indicated by red color are shown in

the deepest area of Port Reitz. However, these are caused by re-suspension of existing

fine materials due to extreme shallowness of the area, which is difficult to eliminate the

indications from the output of this simulation results (Figures 5.18 and 5.19).

74

Figure 5.18: Turbidity water dispersion due to dredging works at Turning Basin and

temporary dumping at New Container Terminal during NE Monsoon.

75

Figure 5.19: Turbidity water dispersion due to dredging works at Turning Basin and

temporary dumping at New Container Terminal during SE Monsoon.

5.6.4 The potential for sediment resuspension.

The results of the hydrodynamic model were then used to assess, amongst other things,

the sedimentation and turbidity as a result of dredging activities and consequently

potential impacts on marine flora, fauna and biological processes within the study area.

Figures 5.20 and 5.21 show the predicted extent and level of concentrations of

suspended sediment expected at the Turning Basin and Offshore site following 10 days

of constant dredging.

76

Figure 5.20: Results of numerical simulations of siltation before and after dredging

during the South East Monsoon season and the siltation difference before and after

dredging.

77

Figure 5.21: Results of numerical simulations of siltation before and after dredging

during the North East Monsoon season and the siltation difference before and after

dredging.

5.6.5 Hydrodynamic modeling of water quality impacts

Dredging increases water turbidity and relocation of dredged material to an offshore site

can spread the plume over a greater area. The approach to developing the

hydrodynamic model for the project was to predict the spatial extent of impact from

turbid plumes as well as the concentrations of suspended sediments that would be

experienced by biota through the reduction in available photosynthetic light and through

physical smothering of deposited dredge sediments. This approach enabled the project

team to predict turbidity related impacts and develop management and mitigation

strategies prior to the commencement of the dredging project and occurrence of impacts.

78

The focus was on the dredging process to enable a responsive approach to

management. As part of the predictive monitoring approach, mitigation measures based

on tolerance values were developed for sensitive habitats and then used to develop

management responses.

5.7 Concluding Remarks 5.7.1 Hydrodynamic Characteristics This study provides baseline data and information on the hydrodynamic characteristics

of Kilindini harbor, in Mombasa, Kenya.

Water level variations in Kilindini harbor are typically semi-diurnal with spring tide range

of 3.12 m and neap tide range of 1.04 m at the entrance. The mean tide range is 2.3m.

Reasonable predictions of water levels can be obtained by using only fourteen tidal

constituents. Astronomical tides account for more than 90% of water level variations in

the harbour.

Water movements follow closely the tidal rhythm. There is a phase difference of about

3.45 hours between current velocities and water levels. During both spring and neap

tides, the currents are confined along the axis of the main channel.

There is an asymmetry of ebb-dominance with ebb currents being stronger than flood

currents. Maximum ebb and flood velocities are 0.8 ms-1 and 0.5 ms-1 respectively. This

situation tends to favour a net export of materials (including sediments) out of the

system. Typically, flood tide last for 6.58 hours while ebb tide extends for 6.04 hours

within the harbor.

Temperature variations are diurnal with maximum values occurring at about midday and

during the afternoon within the harbor. These variations are slightly sensitive to the semi

diurnal variations caused by the tides.

Meteorological forcing due to wind stress or fluctuations in air pressure play a minor role

in the harbour-ocean exchange processes. This indicates that water movements in

Kilindini harbor are exclusively caused by the tides.

79

Harmonic and spectral analysis methods are useful tools for characterization of

estuarine flows. Both methods describe fairly well the hydrodynamic characteristics of

Kilindini harbor.

5.7.2 Numerical Modeling Three-Dimensional hydrodynamic models coupled with advection-diffusion term can be

used to simulate the hydrodynamics of Kilindini harbor including the transport of

suspended sediments.

The model applied in this study was used to predict the effects of the proposed dredging

scheme on tidal flows, waves and sediment transport using four scenarios examined

during both the NE and SE monsoon seasons. The results of the hydrodynamic model

were then used to assess, amongst other things, the sedimentation and turbidity as a

result of dredging activities and consequently potential impact on sensitive habitats in

the harbor and nearby areas.

The development and application of the hydrodynamic model for the project was to

predict the spatial extent of impact from turbid plumes as well as the concentrations of

suspended sediments. This approach enabled the project team to predict turbidity

related impacts and develop management and mitigation strategies prior to the

commencement of the dredging project and occurrence of associated impacts.

Modelling results indicates that sea levels will not be impacted by the dredging and that

the tidal water levels will be reduced very slightly by about 20 mm in the harbor. The

results also indicate that there will be no change in the current speeds in the harbor or

the dredged channel after the dredging. However, there will be a small decrease in

current speeds through the entrance of the Harbour associated with the increase in the

cross sectional area. There shall be a slight decrease of current in the Turning Basin

because of the deepening. Model results also indicate reduced ebb-dominance in tidal

asymmetry in the harbor.

Results of the model further indicated that changes to wave heights (increase or

decrease) were negligible (less than 10% change) implying that the proposed dredging

works is not likely to alter alongshore erosion and sediment transport processes.

80

6. THE BIOLOGICAL ENVIRONMENT 6.1 Introduction The present project proposes to dredge the shipping route leading to the Port of

Mombasa to deepen and widen the channel at specific locations (Figure 1.1, 4.1). Due to

the potential impacts to the marine environment and human use features associated with

it, background ecological checks were requested and surveys were carried out to

address key environmental concerns and issues, identify potential impacts and

recommend workable mitigation strategies. Consultative meetings were done with the

proponent (KPA) and it’s engineering and port development consultants (Japan Port

Consultants, BAC Engineering & Architecture Ltd.) to gain insight into project design and

scope, and preliminary joint site visits made to gauge the extent of the project area

(proposed dredge areas along shipping route and the nature of the environment existing

thereon).

The Port of Mombasa is surrounded by areas of high natural resource value. Figure 6.1

shows the main coastal type, biological resource, and human use features associated

with the entrance channel (and part of Kilindini harbour). They include a rocky coast at

Shelly Beach, a sheltered sandy beach at Mkomani (Tudor), an exposed sandy beach at

Shelly and Nyali Beach which are also potential turtle nestling sites, contiguous or

isolated patches of fringing coral reefs and reef flats, back-reef lagoons, several hotel

areas, and a marine protected area (Mombasa Marine Park and Nature Reserve). In

Figure 6.2, the main coastal type, biological resource, and human use features

associated with the western end of Port Reitz creek are shown. These include tidal flats

and mud banks, river mouth or creeks, mangroves, relics of coastal forests, small scale

fishing areas, fish landing sites, and harbour areas.

Three perennial rivers – Mwache, Mambone, and Chasimba (Pembe) – feed into the

western end of Port Reitz creek, while three seasonal rivers (Kombeni, Tsatu, Mtsapuni)

flow into Tudor Creek. The mangroves around the port areas and the intertidal mudflats

are a bird sanctuary, and provide other ecological services for fish and shrimp breeding

grounds (Little et al. 1988, Wakwabi and Jaccarini 1993, Seys et al. 1995, Zimmerman

et al. 1995, Wakwabi and Mees 1999, Fulanda 2002, Fisheries Dept 2006, Adala et al,

1997). The waters of the port areas are widely used for various maritime and shipping

activities (KPA, 2004. 2005). In Tudor creek, water sports activities (boating, water skiing,

81

swimming, etc) take place and there are two facilities (Tudor water sports and Mombasa

water sports) for deep sea water fishing and sport activities.

To assess and address issues and concerns of the impacts of the proposed dredging

and dumping activities, a biological baseline study was conducted with careful selection

of study site locations focusing on flora and fauna in 3 communities: water column, soft

sediment and hard substrata habitats, critical habitats (corals, seagrass beds,

mangroves, nearby beach and tidal flat areas used by avifauna, turtles, and humans)

and the MPA. The biological study also benefited from parallel assessments of

hydrodynamic conditions and forcing (physical environmental data) and physio-chemical

conditions of the biotic environment, as well as air quality and noise levels. An

assessment of the nearby marine conservation area (Mombasa MPA) was also done.

Mombasa Marine National Reserve

Shelly Beach

Nyali

Beach

Entrance Harbour

Kilindini Creek

Tudor Creek

82

Figure 6.1 Coastal type, biological resource, and human use features of the port entrance area, Kilindini harbour and Tudor Creek (after Environmental Sensitivity Map, KenSea; Tychsen 2006)

Port Reitz Bay

Mangrove Is-1 Port Reitz Harbour

R. Mwache MIA R. Mambone

R. Chasimba

Figure 6.2: Coastal type, biological resource, and human use features at the western end of Port Reitz Creek (after Environmental Sensitivity Map, KenSea; Tychsen 2006)

6.2 Methodologies for Biological Studies 6.2.1 Scoping: An environmental review (scoping) was undertaken to identify issues and concerns for

the marine biological environment from lead agencies, NGO’s, private sector investors

and the general public stakeholders (Adala et al, 2007).

83

The ecological survey team and study tools were assembled and comprised scientific

divers, marine ecologists, fish and bird specialists and GIS experts, amongst other

technical specialists, and boats, samplers, measurement equipment and tools (Plate 6.1).

The staff were briefed and de-briefed before and after each field expedition. At all times,

marine safety was affected in accordance with existing KMFRI safety guidelines for

research operations at sea. Quality assurance for field sampling and work protocols was

ensured by adopting the scientific operating procedures in standard use at KMFRI and

working with experienced staff.

Plate 6.1: Part of the ecological team, including divers, and some sampling equipment aboard hired boats used in survey

6.2.2 Fieldwork:

Fieldwork focused on flora and fauna in 3 communities: water column, soft sediment and

hard substrata, critical habitats (corals, seagrass beds, mangroves, beach and tidal flats),

and an assessment of the Mombasa MPA conservation area.

6.2.2.1 Water column assemblages

a) Planktons Water samples were collected from 32 water sampling sites (Figure 6.3). For

microscopic life-forms, planktons samples were collected using plankton nets (Photo D).

Vertical and horizontal tows –plankton nets (100 µm for zooplankton and 200 µm

phytoplankton) – were undertaken. Vertical tows were done from 1m above sea surface,

while horizontal tows were towed for 25 m at about 0.3m/sec. The samples were

washed into a receptacle and fixed in 8% buffered formalin and sent to KMFRI Mombasa

laboratories. In the laboratories, the retained materials were washed into a glass dish

and the biota sorted out under a microscope.

84

Microscopy and computer-aided taxonomic analyses (Plate 6.2) followed standard

methods; e.g. for phytoplankton – the Utermorhl method was used to identify the

phytoplankton. Diatom species were ordered according to Hasle and Syvertsen (1997);

Dinoflagellates according to Steidinger and Tangen (1997); and Flagellates according to

Throndsen (1997), all cited in Carmulo (1997). Zooplankton systematic categories were

counted under a Wild Heerbrugg Stereomicroscope, and all samples were equally

treated according to standard national and international laboratory procedures in use at

KMFRI. Bacterial samples were collected by and analyzed at the Society General

Surveillance (SGS) Mombasa offices using the ISO 9308 PT2 methods.

Plate 6.2: Plankton sampling, microscopic survey and computer-aided taxonomic analysis.

b) Nektons

(i) Fisheries

15 fish landing sites (Figure 6.4) were surveyed for primary catch data (gill-net, trap-

fisheries, and prawn-fisheries Plate 6.3), interviews with fishermen, and aquaculture

potential. Comprehensive data was collected from 5 years fish landing data (2003 –

2007) from the 15 landing sites (Frame survey data 2007) that included all the gazette

landing sites listed in Figure 6.4. Data collected and analyzed (5 year data sets) paid

particular attention to catch effort, crafts used, ecological groups/fish categories

(species/taxa and dominant groups represented, including sightings for charismatic

fauna – dugongs, turtles, dolphins, sharks, etc), fish production (fish landings, catch

trend), and other potential and existing aquaculture/mariculture sites and initiatives.

85

86

Offshore Dumping

Temporally Dumping

Water column/ Soft substrata/ sed benthos /: 32 points Soft substrata/sediment transects 4 sites

Hard substrate/sessile inverts/sponge/seaweeds/ slow mobile fauna: 12 points

Fisheries/turtle nests/birds survey: 15 points

Mangrove/tidal flats survey: 10 sites

Coral quality survey: 4 sites

Seagrass study transects 4 sites

15

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Figure 6.3: Sampling site locations and transects for baseline studies (Fisheries landing sites are shown in Fig 6.4).

87

Figure 6.4: Sampling site locations for fisheries data at gazette fish landing sites including sites visited mentioned in the text

Plate 6.3: Field survey of rare / critical ecological fish types and ID (top) socio-economic (gear - mid and catch - bottom) for fish, shell-fish and prawn collections.

(ii) Mega-fauna /migratory fauna (reptiles, birds and mammals)

15 sites (same sites as fisheries sites, Figure 6, 4 & Plate 6.4) were surveyed for large faunal incidences

and usage. These sites encompassed beach and tidal flat areas used by avifauna, turtles, and humans.

Bird records were made by an experienced observer hired for that purpose and using standard guides

(Brown et al, 1986; Urban et al, 1988; Fry et al, 1988; Keith et al, 1992; Zimmerman et al., 1996). In

addition, information and data on turtles, avifauna, dugongs, and related charismatic fauna were sourced

from responsible government departments (fisheries department, Kenya wildlife service – Mombasa,

KESCOM, IUCN and WWF conservation agencies, local universities and KMFRI contacts). Additional

information was collated from published reports and papers.

Plate 6.4: Bird survey on mangrove tress and tidal flats

6.2.2.2 Sediment (benthic) assemblages

a) Benthic surveys:

i. Soft sediment infauna

32 sediment cores were taken by divers from specified locations (see Figure 6.3). Coring was

carried out by divers using 50cm long clear perspex tubes with a 6.4 cm internal diameter and

enclosed with rubber bungs at each end (Plate 6.5). Coring procedures were as specified in

Hewitt and Martin (1996, 2000). Sub-sample core samples were taken for grain size and

organic matter analysis.

Plate 6.5: Sediment field survey and processing for benthic collections and laboratory ID using microscopy and technical guides.

The fauna samples were sieved in field through a 0.5mm mesh tray, care being taken not to

introduce sea water into the sample to avoid water-column ichthyoplankton contamination. The

samples retained were preserved in 10% buffered formalin and sent to KMFRI Mombasa

laboratories. In the laboratories, the retained materials were washed into a glass dish and the

infauna sorted out under a microscope and later identified according to standard identification

kits.

ii. Hard substrata invertebrates

12 sites for sessile and cryptic invertebrates were sampled at specified locations (see Figure

6.3 & Plate 6.6). Sampling protocol was to scrape the fauna and flora from replicate 25 X 25 cm

quadrates and concomitantly carry out visual diver searches at the same sites, as specified in

Hewitt and Martin (1996, 2000). Additional collections were made of the larger sessile

invertebrates such as sponges, hydrozoans and bryozoans (which also provide habitat for

smaller animals).

Plate 6.6: Hard substrata survey and collections for laboratory ID from 25m2 quadrants

The retrieved samples were identified in-situ where possible using water-proof identification

sheets / manuals. Unfamiliar species were stuffed into plastic bags and preserved in 10%

buffered formalin and sent to KMFRI Mombasa laboratories for analysis using standard

identification kits.

b) Slow mobile fauna

12 underwater visual census (UVC) and snapshots were conducted at specified locations (see

Figure 6.3) as specified in Hewitt and Martin (1996, 2000) by divers (deep sites), snorkeling

(shallow sites) or beach walk (shallow or exposed sites).

The observed organisms were identified in-situ where possible using identification sheets.

Unfamiliar species will be collected and stuffed into plastic bags and preserved in 10% buffered

formalin and sent to KMFRI Mombasa laboratories for analysis using standard identification kits.

6.2.2.3 Critical habitats a) Coral reef beds and associated substrata communities (seagrass, seaweeds,

algae, sponge)

LandSat Imagery was used to select sites, on the basis of the depth limit of coral and availability

of hard substrate and the proximity to the proposed dredging and dumping activities. The

average depth for the selected sites was approximately eight meters. Landsat TM image for

2005 was downloaded from USGS website (Figure 6.5). Among the pre-processing steps

carried out were: subset to the study area and the dark pixel subtraction to remove the effect of

atmosphere. Benthic substrate were sampled using a 10 line transect method where the

substrate > 3cm beneath the transect line was measured and recorded (McClanahan and Shafir,

1990).

Nine 10m transects (Plate 6.7) were laid in each site where major substrate categories were

recorded: hard coral, soft coral, sea grass, sponge, sand and algae. Four sites were selected

where benthic surveys were carried out to identify the major substrate types in the selected

sites. 3 sites selected were on the southern tip of the Mombasa marine reserve, extending to

the shallow end of the Tudor channel, and one site at Shelly beach in the south close to port

entrance. Site 4 is a heavily fished site with beach seine being the major gear used. Sites 1, 2,

and 3 are protected under ‘Reserve’ category. However no form of management has been

initiated and as a consequence heavy fishing takes place in these areas.

Figure 6.3: Landsat image (bands arrangement 3-2-1) showing the port entrance and the study sites studied for coral cover

Plate 6. 7: Coral field survey and some coral genera and associated invertebrates encountered

b) Seagrass beds and associated communities (seaweeds, algae, sponge)

Sampling for seagrass community structure and associated communities (seaweeds, algae,

sponge) was carried at 4 sites (Figure 6.3). The structural features of seagrass and other

substrata conditions were assessed from 10 quadrats (50 x 50 cm) at each site. Species

composition, canopy height and percentage cover (seagrass research methods – Phillips and

Meñez 1988 and Phillips and McRoy 1990) were made. Assessments were also made of the

sizes and area extent of within-bed bare locations (sand or rubble) and the composition and

sizes (percentage cover) of other non-seagrass substratum structures.

c) Mangroves and tidal flats

Data and information from an environmental sensitivity atlas (Tychsen 2006) was used

alongside field surveys in selected spots. 10 mangrove survey locations (Figure 6.3 & Plate 6.8))

were sampled by representative transect and quadrant sampling. Community structure and

regeneration patterns and understory structure were described for the sampled sites. In addition,

12 sub-plots were surveyed for mangrove macrobenthos (mostly for indicative crustaceans and

molluscans).

Plate 6.8: Mangrove field survey for plant structure and associate macro-invertebrates

6.2.2.4 Environmental data a) Basic abiotic conditions

Basic environmental data (conductivity, temperature, salinity, dissolved oxygen, pH, and

turbidity) at specified sites during were collected at all the 32 water and sediment survey

locations by a laboratory contracted to do chemical analysis, SGS-Kenya, (ISO 9001:2000; ISO

14001, OHSAS 18001; ISO/IEC 17025 and 14000certified laboratory). In addition, air quality

and background noise levels were measured at selected locations representative of Port Reitz,

Kilindini Creek and Entrance Channel areas.

b) Sediment analysis From the 32 benthic core locations, sub-sample sediment samples were collected and stored in

sealed plastic containers until analysis at the Geoff Griffiths and Associates Company

laboratories in Nairobi (NEMA certified laboratory). Particle size analyses were done using both

Wenton sieves (range from 0.075 to 75) and hydrometer analysis (range from 0.080 to 0.005)

and calculating the specific gravity.

6.2.2.5 MPA survey and analysis The existing documented biodiversity at Mombasa Marine Park and Reserve (Mombasa MNPR)

was reviewed from lead agencies and re-compiled. The information obtained was compared

with information from other national marine parks and reserves.

6.2.2.6 Impact analysis, Mitigations and Monitoring plan

Impact characterization and analysis, and mitigations measures and monitoring plans were

developed across broad categories covering the holistic nature of marine dynamics and

integrating physical, chemical and biological aspects. Monitoring plans proposed involved an

integrated approach, and included parameters, locations, frequencies, duration, target values,

required cost, human resource and effective institutional arrangements.

6.3 Baseline Characterizations 6.3.1 Water Column Assemblages – Planktons a) Phytoplankton

About 40 species were represented out of which a few potentially toxic forms (dinoflagellates –

Alexandrium and Dinophysis) responsible for algal blooms, fish kills and human intoxication

were present. Table 6.1 summarizes the phytoplankton distributions in the 3 study divisions.

The diatoms were the majority followed by dinoflagellates. The flagellates were rare (Figure 6.6)

Other phytoplankton features at the three sites included the following observations:

1. Relatively high diversity at Port Reitz – suggestive of differences in oceanographic

conditions between this and other sites (maybe relative high nutrient areas in P. Reitz

areas as suggested in literature)

2. Some populations are common at three sites – suggestive of their wide distributions

either due to water driven mixing/transport or plastic adaptive strategies;

3. Few are exclusive to inner or outer sites – oceanic vs estuarine indicative mutual

exclusivity either due to abiotic and/or abiotic conditions or interactive effects

b) Zooplankton The following statements can be made of zooplankton assemblages (Appendix-3):

1. About 120 species were represented out of which several potentially from breeders

(eggs) and nursery forms (juveniles; e.g., copepod nauplii were present.

2. More zooplankton types and numbers, and the young stages of many fauna were

obtained in Port Reitz waters than from Shelly beach.

3. Relatively high forms of eggs and juveniles at Port Reitz – suggestive of significant

areas important for life stage cycles of fauna represented.

4. At Port Reitz, cyclopoida and calanoida were the most abundant, followed by mollusca,

appendicularia and copepod nauplii. Pisces, cirripied nauplii, and polychaeta were

present in intermediate numbers.

5. Main taxa represented in Port Reitz samples were distributed as shown in Figure 6.7.

Table 6.1: Water column biota (phytoplankton) in three divisions of Port Reitz, Kilindini and the Entrance Harbour

Port Reitz Kilindini Entrance Harbour

Main Spp Counts Main Spp Counts Main Spp Counts

Ceratium furca 97 Ceratium furca 74 Ceratium furca 18

Pleurosigma normanii 30 Protoperidinium spp 48 Pleurosigma normanii 17

Navicula spp 22 Coscinodiscus spp 26 Coscinodiscus spp 14

Thalassiosira eccentrica 21 Thalassionema nitzschioides 23 Navicula spp 12

Alexandrium catenella 20 Pleurosigma capense 18 Skeletonema costatum 11

Nitzschia spp 18 Dictyocha fibula 11 Thalassionema nitzschioides 11

Thalassionema nitzschioides 17 Chaetoceros spp 9 Chaetoceros spp 10

Protoperidinium spp 15 Nitzschia closterium 8 Dictyocha fibula 8

Ditylum brightwelli 12 Pleurosigma normanii 8 Thalassiosira anguste-lineata 8

Dictyocha fibula 11 Thalassiosira spp 8 Nitzschia spp 7

Pleurosigma capense 10 Skeletonema costatum 7 Pleurosigma directum 7

diatom dinoflagellate flagellate

Figure 6.4: Proportions of major phytoplankton groups in the samples analyzed. See appendix- for details on specific categories

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lan

kto

n)

Figure 6. 5: Occurrence of zooplankton taxa in water samples from Port Reitz

c) Coliform bacteria

For coliforms types and composition, there were no differences between the various forms

enumerated. All fecal coliforms present were comprised by E. coli. The mpn values in 100ml

were similar at 23mpn/100mls or undetected at all sites in Port Reitz, Kilindini and Shelly

beach.

6.3.2 Water Column Assemblages – Fisheries

6.3.2.1 Distribution of fishing effort

A total of 1349 fishers are recorded to fish and land at 28 landing sites of Mombasa District

(Marine Fisheries Frame Survey 2006). However, 324 of these fishers fish within the Port Reitz

creek with majority fishers landing in Tsunza (~55 %). In Likoni division the fishers are

distributed as follows; Tsunza (227) Old ferry (48), Mtongwe (35) and Mwangala (14) as shown

in Figure 6.8. In Changamwe division there is a total of 313 fishers from the following landing

sites; Mkupe- Maweni (147), Kwa Skembo ( 78 ), Kitanga Juu (66) and Kwa Kanji (22) (Figure

6.9). There are two landing sites in the Old port area namely; Mlango wa papa and Old port

town. A total of 58 fishers are recorded to land in the two sites. According to frame survey report

only 14 fishers use sails, paddles or walk to the fishing ground, the rest have Mashua boats

fitted with outboard or inboard engines.

Fishing within the Port Reizt creek is largely artisanal and dug-out canoes propelled by either

sail or paddles are the main fishing boats. There are three boats that are propelled by out-

board engines (15 Hp). A total of 230 boats fish within the creek with two or three crew

members per boat depended on the fishing area and target species/fishing method. There are

also fishers who walk to the fishing ground especially those that use traps. A total of 18 fishers

are recorded as foot fishers 12 of them landing at the Old ferry and 6 in Mtongwe (Figure 6.8),

while 17 foot fishers are recorded to land at landing sites of Shelly beach area (Kibuyuni, Shelly

beach and Mavovoni). Fishers in Shelly beach area are estimated at 65 with a total of 18 boats

(Frame Survey 2006).

Figure 6.6: No of foot fishers and boats per landing sites Likoni

Figure 6.7: No of boats and fishers per landing sites / Changamwe

Cast nets and marine seine nets are commonly used to harvest prawns. The major prawn

fishing and landing areas are Mkupe-Maweni, Kitanga Juu and Tsunza. Other gears largely

used include gill nets, Hand lines traditional traps and spear guns. Most gillnet used are below

2½" (108) while very few are of 5" and above. Hand lines are largely used within these fishing

grounds and targets the snappers and scavengers.

Fishing grounds along the Creek are shared by the various fisher groups depended on target

species, fishing gear and or method of propulsion to access grounds. Fishing in Shelly beach

area is depended on the reef and most fishing is done at the adjacent fishing reef areas.

6.3.2.2 The ecological resources information

There are 27 fish species groups from 12 families landed from the Port Reitz creek and Shelly

beach fishing areas (Table 6.2) Although most fish groups are harvested throughout the year

some pelagic species like kingfish and Tuna are mostly targeted from December to April by Old

ferry (Likoni) and Shelly beach fishermen. However, high production is noted for demersal fish

species and crustacea especially prawns which form the bulk of harvest from Port Reitz creek.

This creek not only supports and home to resident species, but also other predatory species

such as sharks, grunters and squids. For example catches of small sharks and other pelagic

species including the squids are reported and are caught within creek especially during high

tide as the move to search for food. A lot of other fish species also move into the creek to feed.

The creek is believed to be a nursery ground for squids and octopuses. The creek is also rich in

crab fishery with much harvesting within the mangroves. The fishing ground off Shelly beach

landing sites is a major feeding and spawning area for most fish species according to the

fishers. The reefs off Shelly beach are rich in Marine shells and sea cucumber.

Table 6.2: Species composition of landed fish/crustacean (including target species for the area- frame survey data 2006)

Ecological Groups Species/ Taxa Included Dominant Groups

Sharks, rays Carcharhinus sp and manta rays Sharks , Rays

Large pelagics Scomberomorus spp, Thunnus spp, spp, Chorinemus tol

King fish, Tunny fish, queen fish

Other pelagics Rastrelliger spp, Sphyraena spp, Trevallies Baraccudas, little mackerel, trevallies, sardines

Demersal predators Cephalopholis spp, Epinephelus spp, Lutjanus spp, lethrinus spp, Upeneaus spp. Tachyurus spp, Pomadasys spp, Geterin gaterinus

Scavengers, Rock cod, goat fish, grunters and black skin

Other demersals Siganus spp, Callyodon guttatus Rabbit fish, Parrot fish, Unicorn and surgeon

Benthopelagics Mugil cephalus, chanos chanos Mullets Crustacea Penaeus spp, Palinuridae Prawns, lobsters Squids, octopus Loligo spp, Octopus spp Squids , Octopus Marine shells

Sea turtles have been reported (Wamukoya et al 1997) to nest in this area an indication of a

major feeding ground for turtle species. Sharks and Rays harvested in this area are not

reported to species level and there a need to monitor the species as some shark and ray

species are listed as threatened in the IUCN red list.

6.3.2.3 Fish production

Fish species exploited within the dredging and dumping sites are shown Table 6.2. Rabbit fish,

scavengers, Sardines, Sharks/rays, octopus and prawns have contributed to a greater extend to

the Likoni fish landings (Figure 6.10). On average landings from the key species range from 8 to

11 tons according to landing statistics from Likoni fish landing sites (Fisheries statistics). Other

species contribute 2 and 3 tons annually. From the statistical data high catches of 113 and 124

MT are recorded in 2004 and 2005 respectively and dropped to 83 MT tons in 2006 and 2007

(Table 6.3). The landings in Likoni area are highest in 2007 (144). Most of the other species are

recorded as mixed species and contribute to 40 to 50% of the total landings. The highest

catches are for sharks/rays, rabbit fish, and scavengers. The Old Port fish landing statistics

show a total of 71MT valued at 6.7 million Kshs. for 2004 and 63MT valued at 6.0 million Ksh.

for 2005. High catch records are from the month of November to April and most common fish

are sharks/rays, sardines, barracuda, Rabbit fish, king fish, snappers, parrot fish scavengers

and lobsters.

Figure 6.8: Fish landings (kg) at Likoni landing sites for five years

Table 6.3: Total fish production and value for the last 4 years in Port Reitz and Likoni

Year Port Reitz Likoni

Wt (Mt) Value(000’sh) WT (Mt) Value(000’sh) 2004 113 8175 83 7333

2005 124 7247 76 7198

2006 83 6374 79 8463

2007 83 6513 144 17099

6.3.2.4 Seasonality of the fishery by species Figures 8.11 - 8.13 show seasonality in the fish species landed from Port Reitz and Likoni areas.

From these data there is an indication that the fishers heavily depend on the sea during the

North east monsoons and that some species do occur in large quantities in the South East

season. High prawn catches are after the rains. However it is important to note that most of

these species are landed throughout the year with varying quantities depended upon the

prevailing season and the fishing grounds. It should further be noted that due to inaccessibility

of some landing sites some data may not be reported and hence the exact value of the fishery

not adequately quantified.

Figure 6.9: Seasonality in landings of pelagic fish species in Port Reitz creek

Figure 6. 10: Seasonality of landings of key demersal fish species in Port Reitz creek

Figure 6.11: Seasonality of landings of sharks and crustacea in Port Reitz creek

Octopus landings are high in south east monsoon winds from June through to October while

prawns landings are highest after May (Fig 6.14). There are high catches of fish not identified to

species level recorded as mixed others, mixed demersals and mixed pelagic species. The

landings from these groups are 1 to 2 tons per year. Due to the limitation in fishing vessels to

access the fishing grounds there is a clear indication of high dependency on fisheries resources

during the calm sea period.

Figure 6.12: Seasonality in landings of octopus, squids, crustacean Likoni

6.3.2.5 Economic value of the fishery There is a high dependency on the fishery. For example prawns earn the fisher between 1.1 –

1.2 million Kenya shillings, an indication of high productivity in terms of crustacea and a major

source of food protein to residents of Mombasa. Most fish species cost Ksh. 70 to 80 per kg or

even up to 150/- per kg depended on season and fish types. The fish catches earn fishers over

7 million shillings Table 6.3. In this analysis the dependency on the fishery in terms household

and other livelihoods has not been quantified. It is also important to understand economic value

of the ecosystem to be quantified as the loss.

6.3.2.6 The potential and existing Aquaculture/ Mariculture The Port Reitz creek which surrounds the Island town of Mombasa in the south west has a total

coastline area estimated at 2250 ha (Fulanda 2002) and recent survey by Fisheries Department.

Suitable mariculture sites have been estimated to cover over 60% in the swamp areas in the mangroves

(Fulanda and Muturi 2002, other later surveys). Two community crab farming projects exist in Tsunza

and Kwa Skembo area Fresh water fish ponds rearing exists too. Therefore there is a high aquaculture

potential along this creek and any development may lead to loss of potential aquaculture opportunity an

alternative to capture fisheries and hence enhancement of food security in this area.

6.3.3 Sediment (benthic) assemblages 6.3.3.1 The soft sediments benthos The macrobenthic community had about 20 different species identities from Port Reitz (15

samples) and about 16 from Shelly Beach (15 samples) (Figure 6.15 and 6.16). In terms of

dominance, Port Reitz area was dominated by Nassarius coronatus and Oliva bulbosa, though

several unidentified Nereidae and Epitoniidae sp were also dominant as were oligochaetes

(Figure 6.15). At Shelly Beach, Nassarius coronatus, Baseodiscus unistriatus and Terebra

nebulosa, were the dominant groups. Platorchestia platensis and Paratanaidae sp were also

encountered in moderate numbers. In comparison, Port Reitz areas had more macrobenthos

per unit area than Shelly Beach (Figure 6.15 and 6.16).

0

10

20

30

40

50

60

70

Nass

arius co

rona

tus

Nere

idae

Oliv

a bulbo

sa

Epito

niidae

sp

Olig

ocha

eta

Bas

eodiscu

s uni

stria

tus

Bot

ridae

sp

Par

atanai

dae

Tereb

ra nebu

losa

Arc

hite

cton

ica per

spec

tiva

Plato

rche

stia sp

Ostra

coda

sp

Par

aneba

lia sp

Ano

dont

ia e

dent

ula

Calp

urnus

verru

cosu

s

Jant

harin

a glo

bosa

Litto

ralia

glabr

ata

Natic

a gu

alte

riana

Tylodi

plax

derij

ardi

Port Reitz benthic species ID

ab

un

dan

ce (

no

. in

15 s

am

ple

s)

Figure 6.13: Macrobenthos from Port Reitz

Data from the Mombasa port survey (Globallast Port Survey 2004, KMFRI, 2005) where over

700 specimen were collected (31 sites, 10 sampling methods), showed dominant groups

present in the Port waters were represented by polychaetes, sipunculids, sponges, oysters,

ascidians, barnacles, solitary corals, hydrozoans, crabs, algae, and fishes. About 70 general

groups and common names belonging to a wide range of Phyla, Classes, Orders and Families

of classification were thus estimated (Figure 6.17)

0

5

10

15

20

25

Nassa

rius coronatus

Baseodiscus unistriatus

Tereb

ra nebulosa

Platorchestia platensis

Paratanaidae

Ceratonereis erythraensis

Nereidae

Anopla

Argathona macron

ema

Polyopthalm

us pictus

Ostracoda

Oligochaeta

Botrididae sp

Macrophiothrix lo

nngipeda

Paratanaidae

Platorchestia platensis

Shelly Beach benthic species ID

abun

dance (no in 15 sa

mples

)

Figure 6.14: Macrobenthos from Shelly Beach

Occurence of common taxa

0

10

20

30

40

50

60

70

80

zo

oa

nth

ids

po

ych

ate

s

sip

un

cu

lid

s

spo

ng

es

oy

ster s

hell

s

asc

idia

ns

ba

rn

acle

s

soli

tary

co

ra

ls

bris

tle s

tars

cra

bs

hy

dro

zo

an

s

alg

ae

fish

spacimen taxa

Nu

mb

ers

Figure 6.15: Occurrence of common taxa in benthic samples from Globallast survey (Source - KMFRI 2006)

6.3.3.2 The epifaunal and infauna benthos

Assortments of epiphytic faunal communities were encountered. At Shelly beach they were

either sessile on the substratum or on seagrass and seaweeds – hydroids, sponges, and

ascidians. At Port Reitz, mangrove epiphytes (e.g., Balanus, Amphitrite and Ostrea sp on

Rhozophora trunks and prop roots) were observed. Some of these were seaweeds and are

listed under seaweeds section.

6.3.3.3 Hard substrata benthos and slow invertebrates

Hard substrata benthos and slow invertebrates from underwater visual census, scrapes or

observed in transect observations or still photo-imagery included the following groups (Table

6.4).

Table 6.4: Benthic invertebrate assemblages at the Port Reitz, Shelly and Nyali Beach waters based on 10 transect observations (September – November 2006)

Site Benthos Comments

Port Reitz Oysters Crabs (mostly mangrove types and few sandy types – see Table details) Barnacles

Oysters and barnacles growing mostly on hard substrata off the seawall at berth-19 (Kilindini Oil Terminal)

Shelly Beach Corals – hard and soft see Table details) Sponges Acanthanster Sea urchins – Diadema, Echinometra, Tripenestus

Corals and sponges species sedentary; Acanthanster (rare) and sea urchins (common) are predatory species indicating some ecological imbalances

Nyali Beach

Corals – hard and soft see Table details) Sponges Acanthanster Sea urchins – Diadema, Echinometra, Tripenestus

Corals and sponges species sedentary; Acanthanster (rare) and sea urchins (common) are predatory species indicating some ecological imbalances

Beach-walk observations revealed fauna on rocks in the upper part of intertidal zone had a

sparse biological activity, with mostly unicellular algae and fleshy alga, and a fauna of chitons

and limpets and some amphibian crustaceans.

6.3.4 Critical Habitats:

6.3.4.1 Coral reefs and rocky platform communities (Andromache and Leven reefs) Results from the four study sites show that algae and sea grass are the dominant cover in all

the studied sites. All the algal types and sea grass were summed into one substrate category.

Coral cover varied among the studied sites. Site2 had the highest coral cover with 32% while

the lowest coral cover observed was 11.9% in site4. Despite this being a fished site, corals in

site 2 is comparable to that observed in some of the Kenya’s Marine Protected Areas. This

indicates that this area (site-2) is important for hard corals. These corals grow in relatively high

water flow, and could be a source of coral larvae for locations further north of the Marine

National Reserve. Factors which affect these coral habitats among others include trampling by

fishermen. 21 coral genera were counted in all the three sites with site 1 having the highest

number of coral genera (Table 6.5). Site 4 was less diverse with only 7 taxa.

Site 4 had the highest algal cover, dominated by turf algae and the Sargassum macro algae.

The latter do well in high energy areas such as in site 4. The removal of herbivorous fish and

trophy collections or scavenging have also led to the low coral cover that was observed here as

these activities hamper coral recruitment and contribute to low herbivory which leads to

increase in macro algal cover.

Table 6.5: Summary of percentage cover of the major substrate categories in the four studied sites

Site 1 Site 2 Site 3 Site 4

Mean Mean Error Mean Mean Error Mean Mean Error Mean Mean Error

Hard Coral 26.5 2.9 32.4 1.8 13.9 1.8 11.9 2.8

Algae and sea grass 64.9 9.2 59.9 4.6 80.8 10.3 79.2 3.3

Soft coral 2.1 0.6 2.1 0.5 1.2 0.5 0.1 0.1

Sponge 0.1 0.1 0.0 0.0 0.7 0.4 0.2 0.2

Bare substrate 6.3 1.3 5.6 1.1 3.4 1.3 8.7 3.5

Table 6.6: Summary of the number of hard coral genera observed in the studied sites.

Site

Acropora

Alveopora

Astreo

Astreopora

Cyphastrea

Echinophyllia

Echinphora

Favia

Favites

Galaxea

Goniastrea

Goniopora

Hydnophora

Leptoria

Millepora

Montipora

Pavona

Platygyra

Pocillopora

Porites bran

ching

Porites mas

sive

Total tax

a

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 152 1 1 1 1 1 1 1 1 1 1 1 1 1 133 1 1 1 1 1 1 1 1 1 1 1 1 124 1 1 1 1 1 1 1 7

Following the major 1998 El Nino, most corals at Shelly beach areas must have been killed as

seen from dead tops of most hard corals there. The few hard corals encountered (Table 6.6)

comprised less than 15% of the total benthic cover, and are not yet in a state of good recovery

as seen in evidence of breakages, erosion of newly dead corals and increased dominance by

fleshy/tuft algae. Some scleractina corals, in particular Horastrea indica, which is listed as

endemic to the western Indian Ocean was not seen in this survey even though it has an

occurance potential.

6.3.4.2 Seagrass Beds

There were no seagrass beds on study sites at Port Reitz area, except for a small patch of bed

in an areas between Ras Kikangoni and the Kenya Navy jetty (Table 6.7). All seagrass species

reported in this study were found at the Shelly Beach and Nyali beach areas, where a total of

eight species were recorded, in particularly high densities were encountered at the entrance

areas of the Port (Shelly and Nyali beach), and these are listed in Table 6.7

Table 6.7: Sea grass species at some sites of the Port of Mombasa

S. no Species ID

Shelly Beach (relative species % cover* of

species encountered)1 Port Reitz (KN jetty/quay)2

Transect-S1 Transect-S2 Transect-S3 presence

180-m 220-m 210-m

1 Cymodocea serrulata 15 35 20

2 Cymodocea rotundata 20

3 Halodule uninervis 20

4 Syringodium isoetifolium 15 5 30 √

5 Thalassia hemprichii 10 30 5

6 Thalassodendron ciliutum 30 25 15

7 Halophila ovalis 5 5 5 √

8 Halodule spp 5 5 √

Species % cover* relative only for seagrass on defined transect distance.

6.3.4.3 Seaweeds

The seaweeds structure of Port Reitz comprised mostly blue-greens loosely attached on silty

sediments. Patches of Enteromorpha crassa on sediment surfaces, with occasional

occurrences of Padina, Ulva and floating Sargassum were encountered. Some species were

found epiphytic on mangrove roots (e.g., Enteromorpha, Bostrychia and Murrayella spp. on

Avicennia).

At Shelly and Nyali Beach, several species were found that grow attached on reef front, reef

crest, reef flat, and on dead coral debris and sandy pools: Padina, Cystoseira, Dictyosphaeria,

Digenia, Avanthophora, Pseudovalonia, Laurencia, Hypnea, and Dictyota and some forms of

Calcerous algae were some common genera encountered. For a full list of occurrence by

transect points, see Table 6.8.

6.3.4.4 Epiphytic seaweed community

Epiphytic seaweed communities (on seagrass) were encountered. These include the species

Ulva, Caulerpa, Colpomenia, Hydroclathrus, Pocockiella, Jania, Amphiroa, Codium, Gracilaria,

Padina, Stypopodium, Enteromorpha, Galidiella, Sphacelaria, Psedovalonia, and Calcerous algae

6.3.5 Mangrove forest

Table 6.9 summarizes the general characteristics of the main mangrove sites surveyed (existing

forest area > 0.5 acres). In Port Reitz were found the most extensive mangrove forests in the

typical estuarine environment (along 2 major river channels). At the confluence where the two

main rivers (Mwache and Cha Shimba) met on the Port Reitz Channel –an island of Sonneratia

alba mangrove has formed.

108

Table 6.8: Main seaweed genera at two sites of the Port of Mombasa

S. no

Genus ID Shelly Beach (species occurrences on defined transects)1

Port Reitz (occurrences of species at 3 circular quadrats (about 5-m radius) along transects)1

Transect-1 Transect-2 Transect-3 Transect-4 Transect-5 Transect-6 Transect-7 Transect-8 Transect-9 Transect-10 (mangroves)

180-m 220-m 210-m 10m diameter

10m diameter

10m diameter

10m diameter

10m diameter

10m diameter

10m diameter

1 Enteromorpha crassa X X X X X X X

2 Sargassum polyphyllum X X X X

3 Sargassum vulgare X X X

4 Bostrychia X

5 Murrayella X X

6 Padina X

7 Cystoseira X

8 Turbinaria X

9 Acetabularia X X

10 Caulerpa X X

11 Gracilaia X X X X

12 Gelidium X X

13 Dictyosphaeria X

14 Digenia X X X

15 Avanthophora X

16 Pseudovalonia X

17 Laurencia X

18 Hypnea X X

19 Dictyota X

20 Calcerous algae X X X

21 Euchemia X X X

22 Halimeda X X X

Transects 4 – 10 based on 3 observations at 10 m distances

109

Table 6. 9: Mangrove community structure at the study plots in Port Reitz basin

Parameter

Site Kilindini Channel Port Reitz Channel

Tudor Channel

Site-1 Site-1 Site-2 Site-3 Site-4 Site-5 Site-6 Site-7 Site-8 Site-9 Site-10 Site-11 Site-10

Mweza Creek

Mangrove Is-1

Mangrove Is-2

Mangrove Is-3 Mwagonde

Dongo Kundu,

R. Chasimba Creek Tsunza Mwache

Mkupe- Maweni

Kwa Skembo

Kitanga Juu Mkomani

Avg area studied (Ha) 1.5 0.5 1.2 0.5 1.5 2 2 1.5 3 1.5 1.5 0.5 0.25

Spp comp

Rm, Ct, Bg, Am, Lr, Sa Sa Sa Sa

Rm, Ct, Am, Sa

Sa, Rm, Ct, Bg, Am

Sa, Rm, Ct, Bg, Am, Lr

Sa, Xg, Rm, Ct, Bg, Am,

Lr

Sa, Xg, Rm, Ct, Bg, Am,

Lr

Sa, Xg, Rm, Ct, Am

Xg, Rm, Ct, Bg, Am, Lr

Rm, Am, Lr Sa

Dominant adult species Rm - Ct Sa Sa Sa Am Sa - Rm Sa - Rm Sa Sa - Am Am Am Am Sa

Dominant young species Ct - Rm Sa Sa Sa Am Rm - Sa Rm - Am Rm - Ct Rm - Sa - Am Rm - - Sa

Avg ht (m) - adults 2.4 1.7 1,3 0.9 3.8 3.1 3.4 2.2 3.5 2.1 3.1 2.7 2.3 Avg density (no/10m2 pots) - adults 11 ± 3.6 4 ± 2.2 3 ± 1.2 3 ± 1.6 7 ± 4.2 18 ± 8.1 19 ± 17.6 13 ± 6.9

15 ± 5.6 8 ± 5.1 3 ± 2.8

0.2 ± 1.6 4 ± 2.7

Dominant regeneration status (class I, II, III) III III III III I II III III II - - - -

Understory cover

Halophytes (% substratum cover) 10 0 0 0 6 3 5 0 2 5 5 2 0

Associated substratum (feel) sandy to

silty sandy sandy sandy to

silty silty sandy to

silty silty sandy to

silty sandy sandy rocky Adults1 description based on UNESCO 1984; regeneration2 status based on UNESCO 1984 and Kairo 1995.

Key: Am Avicennia marina Ct Ceriops tagal Xg Xylocarpus granatum

Rm Rhizophora mucronata Lr Lumnitzera racemosa Hl Heritiera littoralis

Bg Bruguierra gymnorhiza Sa Sonneratia alba

6.3.6 Deep sea benthos Information and data for potential deep-sea benthos was inferred (predicted) from a synthesis of

secondary information sources, in particular data from the Netherlands Indian Ocean Program

(NIOP) 1990-1995 (NIOP, 1992, 1995) for the Kenyan coast that was based on four transect

points at Kiwayu, Tana, Sabaki and Gazi, at depths: 20m, 50m, 500m, 1000m, and 2000m.

Nematode groups are chosen in this report an indicator species (based on analysis by

Muthumbi, 1998).

Based on depths and genus composition (200 genera described (Muthumbi, 1998)), abundance

and species composition were predicted at specific depths. The general trend in Tyro transects

was high nematode density at shallow depth which decreased up to 1000m, then increased

slightly or decreased slightly up to 2000m. The trend was similar in oxygen concentration, and

therefore oxygen was thought to be influencing nematode density. The most dominant genera

common in all the five depths were Monhystera, Sabatieria, Halalaimus and Daptonema spp.

Acantholaimus spp was also dominant but was absent in the shallowest stations. About 55

species were represented in these main 4 -5 families.

Also based on depths and genus composition, ecological groups were categorized for deep sea

benthos. Using the nematode indicator index, four ecological groups were categorized, with

nematode similarities coinciding with the depths of (i) 20, 50 and 200m; (ii) 20 and 50m; (iii) 500

and 1000m; (iv) 1000 and 2000m). This showed the significance of depth in structuring

ecological groups, and the same trends can be implied for the deep waters off Mombasa port

entrance where dumping will be done.

6.3.7 The Mombasa Marine Park and Reserve (MNPR). The Mombasa Marine National Park and Reserve (MNPR) was gazetted in 1986 under the

Wildlife Conservation and Management Act Cap 3726 of 1977 (revised in 1985). This marine

protected area (MPA) is managed by the Kenya Wildlife Service and lies between Tudor Creek

to the south and Mtwapa creek to the north, of Mombasa District (latitudes 40o 43’ and 40o 15’

and longitudes 30o 55’ and 4o 12’ N.E). The MNPR is zoned into two main management areas,

the Mombasa Marine National Park which is 10 km2 and is encompassed within the larger

Mombasa Marine National Reserve with an area of 200 km2 (Chebures 1989; Nyawira 2001,

Weru et al. 2001). The MNPR lies within 20km of Mombasa Island, and Kilindini Harbour.

In the park area, no activity other than observations is allowed. In the reserve area, line fishing

and trap fishing are allowed but shell collection and beach seining are prohibited.

The Mombasa Marine Protected Area (Park and Reserve) consists of the following main

ecosystems and habitats:-

a. A sand dune and sandy beach extending 20 — 50m from shore. In some areas, sand

dune vegetation including sedges, grasses and palms can be found. These areas are

important nesting grounds for sea turtles (KESCOM 1996).

b. In some areas sand flat extends approximately 100-150m from the beach that is usually

exposed during low tide (4m tidal range). This tidal sand flat is rich with benthic

organisms including tube worms, molluscs, crabs and other benthic crustaceans making

this an important feeding area for shore birds including great herons, egrets, terns, and

various species of seagulls (Seys et al 1995).

c. A lagoon separates the sand flat from an extensive fringing reef. The lagoon is mainly

covered by seagrass beds composed mainly of the species Thalassodendron ciliatum,

Thalassia hemprichii, Syringodium isoetifolium, Halodule wrightii and Halophile ovalis

(GROFLOW 1998, Muthama and Uku, Uku, Gwada). These species are also common

throughout the Kenyan coast (Ochieng and erft……., heminga………. The seagrass

beds within the marine reserve serve as the primary site for artisanal fishing by the local

communities

d. Beyond the lagoon lies the coral reef composed of an inner shallow reef, a reef flat that

is commonly exposed during low tide and a fore reef facing the open sea. The inner reef

is dominated by massive and branching forms of the hard coral Porites (Hamilton and

Brakel 1984) and interspersed by areas of the fleshy algae Sargassum, Turbinaria,

Padina and calcareous algae Halimeda. Many species of coral reef fishes, echinoderms

and shells occur within this lagoon (McClanahan 1990, 1994; Muthiga and Ndirangu

2000). The fore reef has a high percent cover of hard and soft coral species and large

schools of coral reef and pelagic fishes (KWS-CORDIO; 2005). Sea turtles are often

seen foraging in these waters.

e. Beyond the reef in the open ocean, large schools of pelagic fishes, whale sharks,

dolphins and sea turtles are common, while humpback whales are occasionally sighted

on their southward migrations.

f. Shoreward from the high tide mark, a riparian area occurs that has a varied community

of plants and tree species. Although this area is not part of the MPA, it is the home to a

wide range of terrestrial fauna including mammals, birds, reptiles and insects.

g. Two mangrove fringed creeks (Mtwapa and Tudor) border the northern and southern

boundaries of the Mombasa MPA and the seasonal Mtopanga creek drains into the

MPA during the long rains that occur from April through June. Theses creek are

important fisheries areas but are also a major source of sediments and solid waste

pollution into the MPA (Mwangi et al 2001).

h. Data from monitoring programs indicate that the Mombasa MPA has a fairly low

fisheries diversity and abundance relative to other MPA’s, but a fairly high invertebrate

cover (Table 6.10 -6.11). Mombasa MPA also has on average lower hard coral cover;

the algal turf being the dominant benthic cover (Table 6.12).

Table 6. 10: Average densities of fish and standard deviations for the four marine parks. 12 transects of 250 m

2 in each park in two seasons

NE Monsoon

Common name Kisite Malindi Mombasa Watamu

Angelfish 9.00 ± 6.26 1.5 ± 1.87 1.00 ± 1.41 1.58 ± 1.61 Barracuda 0.58 ± 1.93 - - - Butterfly fish 12.83 ± 6.52 7.13 ± 4.2 2.50 ± 3.84 2.75 ± 1.74 Emperors 17.5 ± 26.36 4.63 ± 9.68 2.50 ± 5.48 0.67 ± 0.94 Fusiliers 26.66 ± 44.22 13.3 ± 29.8 - - Goatfish 3.92 ± 2.43 1.00 ± 1.32 1.00 ± 2.00 0.92 ± 1.32 Groupers 5.50 ± 7.91 0.63 ± 0.86 0.25 ± 0.83 1.25 ± 2.35 Grunt/Sweetlips 20.75 ± 26.20 5.13 ± 5.90 2.83 ± 4.84 9.25 ± 8.83 Jacks 1.83 ± 2.37 0.75 ± 1.3 - - Parrotfish 17.42 ± 8.85 13.5 ± 6.54 4.83 ± 4.45 6.83 ± 5.62 Rabbitfish 5.25 ± 5.60 1.50 ± 2.35 1.25 ± 2.42 0.58 ± 1.19 Sharks - - - - Snappers 64.0 ± 108.14 14.38 ± 15.6 3.00 ± 2.68 2.08 ± 2.18 Surgeon fish 24.58 ± 21.39 54.38 ± 15.1 5.00 ± 5.89 28.83 ± 47.79 Triggerfish 2.58 ± 2.25 6.75 ± 4.24 0.58 ± 0.86 2.00 ± 2.58 Wrasses 19.00 ± 8.84 11.75 ± 6.9 3.25 ± 2.13 4.00 ± 3.11

SE Monsoon

Angelfish 5.08 ± 5.77 0.08 ± 0.28 1.08 ± 2.06 0.42 ± 0.49 Barracuda 2.25 ± 5.51 - - - Butterfly fish 5.25 ± 3.06 2.83 ± 2.51 4.75 ± 3.59 2.92 ± 1.32 Emperors 8.33 ± 12.19 - 0.83 ± 1.28 0.92 ± 2.06 Fusiliers 78.57 ± 192.46 3.67 ± 8.20 - 75.33 ± 89.86 Goatfish 7.92 ± 15.48 5.00 ± 6.61 1.25 ± 1.59 2.33 ± 3.25 Groupers 19.75 ± 58.93 1.25 ± 2.24 0.58 ± 0.95 1.08 ± 1.32 Grunt/Sweetlips 14.25 ± 14.01 2.42 ± 3.43 5.83 ± 8.15 19.33 ± 17.61 Jacks 7.75 ± 14.83 0.08 ± 0.28 - - Parrotfish 13.17 ± 7.77 5.58 ± 4.66 4.75 ± 5.28 11.08 ± 8.33 Rabbitfish 19.00 ± 46.01 4.67 ± 4.46 0.42 ± 0.76 5.92 ± 6.73 Sharks 1.42 ± 4.70 - - - Snappers 12.58 ± 17.09 0.67 ± 1.18 2.92 ± 3.77 1.92 ± 2.33 Surgeon fish 22.00 ± 26.10 30.67 ± 33.34 11.67 ± 7.54 24.75 ± 16.32 Triggerfish 5.58 ± 9.35 5.83 ± 4.63 1.33 ± 1.37 0.92 ± 2.02 Wrasses 18.25 ± 23.68 10.67 ± 3.82 22.50 ± 17.22 9.00 ± 8.52

Source: Kenya Wildlife Service and CORDIO Ecological Monitoring Report; 2005.

Table 6.11: Average densities of invertebrates and standard deviations for the four marine parks. The data was collected in 12 transects of 250 m

2 in each park in two different seasons

NE MONSOON

Common name Kisite 0 Malindi 0 Mombasa 0 Watamu

Clams 28 ± 3.08 1 12 ± 1.35 1 30 ± 3.34 1 16 ± 0.98 Crown of thorns 1 ± 0.29 2 - 2 5 ± 0.67 2 - Lobsters - 3 - 3 1 ± 0.30 3 7 ± 1.73 Octopus 3 ± 0.62 4 5 ± 0.51 4 1 ± 0.29 4 - Sea anemone - 5 - 5 - 5 - Sea cucumber 45 ± 3.14 6 11 ± 1.24 6 83 ± 3.40 6 5 ± 0.51 Sea stars 37 ± 3.70 7 15 ± 1.54 7 15 ± 1.66 7 2 ± 0.39 Sea urchins 712 ± 49.71 8 100 ± 10.65 8 1031 ± 56.59 8 305 ± 42.76 Shells 23 ± 1.16 9 10 ± 0.72 9 18 ± 1.73 9 11 ± 1.08

SE MONSOON

Clams 017 ± 1.24 10 8 ± 1.07 10 19 ± 1.74 10 19 ± 2.19 Crown of thorns 1- 11 - 11 12 ± 1.51 11 - Lobsters 2- 12 - 12 4 ± 0.83 12 1 ± 0.29 Octopus 39 ± 2.05 13 - 13 - 13 1 ± 0.29 Sea anemone 45 ± 2.04 14 - 14 - 14 - Sea cucumber 551 ± 4.39 15 9 ± 1.25 15 85 ± 3.43 15 3 ± 0.62 Sea stars 618 ± 2.11 16 2 ± 0.76 16 13 ± 0.83 16 - Sea urchins 71389 ± 173.95 17 27 ± 4.02 17 461 ± 19.14 17 97 ± 19.19 Shells 823 ± 1.73 18 16 ± 2.75 18 18 ± 1.98 18 5 ± 0.67

Source: Kenya Wildlife Service and CORDIO Ecological Monitoring Report; 2005.

Table 6.12: Percentage benthic cover per 10 m transect and the standard deviation

Kisite Mombasa Malindi Watamu Chi-Sq. p

Coralline algae 0.21 ± 1.44 5.00 ± 6.15 56.70 ± 16.44 28.83 ± 49.92 26.86 0.00*

Halimeda 0.00 ± 0.00 0.58 ± 0.90 5.70 ± 4.62 2.00 ± 2.70 10.63 0.01*

Dead Coral 3.42 ± 4.85 2.50 ± 4.01 6.40 ± 4.30 2.75 ± 1.82 23.29 0.00*

Soft Coral 1.75 ± 3.41 0.00 ± 0.00 8.00 ± 25.30 0.00 ± 0.00 3.81 0.28

Fleshy algae 0.50 ± 1.24 2.83 ± 5.06 4.10 ± 5.97 9.25 ± 9.23 7.08 0.07

Sand 1.48 ± 4.83 3.25 ± 2.22 10.50 ± 7.53 4.00 ± 3.25 22.53 0.00*

Hard Coral 48.62 ± 16.62 2.50 ± 5.73 3.80 ± 9.30 0.67 ± 0.98 12.07 0.01*

Rubble 15.80 ± 15.74 3.00 ± 2.80 11.80 ± 15.71 2.08 ± 2.27 17.51 0.00*

Algal Turf 28.19 ± 14.58 1.00 ± 1.48 1.60 ± 2.01 1.58 ± 1.68 20.58 0.00*

Source: Kenya Wildlife Service and CORDIO Ecological Monitoring Report; 2005.

6.3.8 Avifauna (Birds)

Majority of bird species encountered belonged to brackish species as shown in Table 6.13. All

data are based on repeated observations between September and November 2006. From

about 115 bird observations made, about 18 species were noted to use/visit /reside in this area.

A comparison was made in this data with those of the east African coastal and marine

environment resources database and atlas (UNEP 1998) and KMFRI database (Okemwa and

On’ganda personal communication). It was noted that the current field-work observations

yielded fairly good representative information for birdlife in the area. KMFRI records have 26

species counts for Tudor and Port Reitz area.

115

Table 6.13: Avian species at the Port Reitz based on 12 repeated observations (2 x low tides, 2 x high tides, 2 x mornings, 2 x evenings, and twice at two fish-landing sites (Kwa Kanji and Kwa Skembo) during fish landings (flooding tides) between September – November 2006.

Bird abundance (cumulative numbers observed in)

Bird type Species ID Low-tide High-tide Morning Evening Kwa Kanji Kwa

Skembo

Pelican – pink-billed Pelecanus rufescens 1 1 1 2

Egret - big Bubulcus ibis 1 2 1 1 1 1

Egret - small 2 2 1

Egret - yellow-billed 2 2 1 2

Egret - great Egretta alba 2 1 1

Heron - green Butorides striatus 2

Heron - black Egretta ardesiaca 2

Heron cormorant 2 2

Stork - yellow-billed Myctaria ibis 2 2 2

Stork - woolly necked Ciconia episcopus 3 2

Sacred ibis Threskiornis aethiopica 4 2 2 1

Kites - black Milvus migrans 3 4 2 5 5 6

Fish-eagle Haliaetus vocifera 1

Sand-plover Charadrium leschanaultii 2 2 2

Grey-plover Pluvialis squatorola 1 1 2 2 2 2

Sand-piper Xenus cinereus 5 2 2

Gull-billed tern 2 3 1

Kingfisher 1 1

Data for Port Reitz sandy beaches, mudflats, mangrove areas (especially Mangrove Island at the centre of Port Reitz bay) and northern banks. Only at Port Reitz area was a detailed bird watch commissioned.

116

6.3.9 Marine turtles

Five species of sea turtles have been documented as occurring within Kenyan waters

(Frazier 1975): the green turtle (Chelonia mydas), hawksbill turtle (Eretmochelys imbricata),

loggerhead turtle (Caretta caretta), olive ridley turtle (Lepidochelys olivacea) and the

leatherback turtle (Dermochelys coriacea). Of these, green, hawksbill and olive ridley turtles

are known to nest in Kenya.

An aerial survey conducted in 1994 found that sea turtles are widely distributed along the

coastline within the 20m isobath in areas mainly associated with seagrasses and coral reefs,

implicating the presence of a significant foraging turtle population (Wamukoya et al. 1996).

Notable concentrations were observed at certain areas particularly Mpunguti/Wasini,

Takaungu, Watamu, Ungwana Bay, and Lamu and the adjacent offshore islands.

The Kenya government has put in place legislation to protect sea turtles i.e., the Wildlife Act

(Cap 376) and the Fisheries Industry Act (Cap 378). The laws prohibit hunting, removing,

holding, moving and trafficking sea turtles and their products whether dead or alive. However,

there is no legislation protecting key nesting and foraging habitats utilized by sea turtles

except for those falling within Marine Protected Areas (MPAs). As a result, turtle fishing,

turtle by-catch in fishing operations, and poaching of sea turtles and turtle eggs continues

unabated compounded by poor enforcement due to a lack of personnel and facilities

To address the plight of marine turtles, KESCOM was established in 1993 under the

patronage of various government institutions: Kenya Wildlife Services (KWS), Fisheries

Department (FD), Kenya Marine and Fisheries Research Institute (KMFRI), Coast

Development Authority (CDA) and National Museums of Kenya (NMK) and Wildlife Clubs of

Kenya. Various non-governmental organizations, WWF-Kiunga, Baobab Trust, Watamu

Turtle Watch (WTW) and Colobus Trust, have given extensive on-ground support towards

the KESCOM cause. KESCOM therefore represents a national integrated approach to sea

turtle conservation promoting community participation in various conservation activities that

include research and monitoring, public awareness and advocacy.

117

Figure 6.16: Map of the Kenya coast highlighting KESCOM study sites which included Shelly and Nyali beach (near the entrance to the port). South Coast (SC), Mombasa (MSA), Kilifi (KFI), Watamu (WTM), Malindi (MAL), Kipini (KIP) Lamu (LAM), and Kiunga (KIU). (Source: Marine Turtle Newsletter 105:1-6, © 2004).

Between 1997 – 2000, an intensive survey was carried out by KESCOM at the sites shown in

Figure 6.18 which also included the sites near the proposed port project activity sites.

Identification of key nesting sites is an ongoing process. From this survey, the nesting and

mortality data reported to KESCOM showed that:

a) Key nesting sites included Shelly beach and Nyali along the Mombasa beach stretch (see

Figure 6.18)

b) the nesting season in Kenya is year-round;

c) The green turtle is the most common species nesting and foraging along the Kenyan

coast.

d) Despite the fact that sea turtles have been reported to nest/feed at Shelly Beach, data is

still incomplete for specific turtle habitats, nestling and feeding areas, size and status of

turtle populations, including breeding populations and migrations, factors affecting the

survival of egg clutches and hatchlings (especially factors associated with people, such

as presence of feral animals), and harvest and trade regimes. The precautionary principle

118

in management control applies (e.g., code of conduct in responsible fishing). The data

shortcomings are being addressed through an integrated management of marine turtle

population, of which KESCOM is playing a pivotal role.

Data gaps

a. Lack of good data on the ecological processes (scale-related processes on

productivity, trophic dynamics, fluxes and connectivity, interactions, larval dispersal

patterns, etc.,) for the Port area environments

b. Lack of good resource maps data on the submerged resources (habitats, condition,

etc.,) for the Port area environments

c. Lack of good data on the strengths of ecological relationships and linkages between

and within Port habitats /communities /biounits

d. Up till now, hydrodynamic model results for water movements and larval dispersal

patterns did not exist and verifications and validations of current model predictions

will be necessary.

119

7. WATER AND SEDIMENT QUALITY

7.1 Introduction

The drastic increase in water turbidity as a result of dredging for port development and

maintenance is about the most visible and significant impact on the water quality. Planned

dredging activities in the Mombasa port are expected to introduce such high loads of

suspended sediments in the water column that will make fishing in the harbour creek

daunting. This is likely to impact negatively on the livelihood of the artisanal fishers operating

in the Kilindini and Port Reitz creeks. The enhanced levels of suspended sediments will have

the potential of increasing the concentration and of associated contaminants such as heavy

metals and hydrocarbons in the water column. Indeed exposing contaminated sediments

from reducing bottom conditions to oxidising conditions in the water column may increase the

bioavailability of certain toxic heavy metals. Ocean disposal of dredged material is a

preferred option, but is subject to an acceptable quality of the sediments that will ensure no

adverse impacts on the environment and animal life.

In this study the prevailing water and sediment quality from the Kilindini and Port Reitz

creeks including the planned Turning Basin were investigated with the aim of assessing the

levels of contamination with toxic heavy metals. The findings form the basis of

recommendations on environmentally safe disposal of the sediments.

7.2 Methodology 7.2.1 Description of sampling area The study area comprised the entire Port Reitz and Kilindini creeks, with sampling points

located along the Navigation Channel in Kilindini and the Turning Basin in Port Reitz (Fig.

7.1). The sampling stations are denoted A to G in the figure, with several sampling points

within station G.

Water samples were collected from the sub-surface layer (about 1 m depth) and bottom layer

in duplicate. In deeper stations (depth exceeding 10 m) water samples at approximately mid-

depth were collected. Sediment samples were obtained by diving and using 30 cm plastic

hand-held corers. Sediment cores were sectioned into 10 cm top and 10 cm bottom sub-

samples. All samples were stored appropriately for analysis at the SGS Laboratories,

Mombasa and the Department of Mines and Geology Laboratories in Nairobi.

Physico-chemical parameters that were measured in situ included water temperature, pH

and salinity. In the laboratory water samples were analysed for ammonia, nitrate/nitrite and

120

phosphate. Dissolved heavy metals analysed included Cd, Hg, Pb, Cr and As. Sediment

samples were analysed for the heavy metals Cd, Hg, Pb, Cr and As. Other parameters

determined organic carbon content (loss on ignition).

Figure 7.1: Map of study area showing sampling sites

7.2.2 Results and Discussion

7.2.2.1 Water quality

Temperatures in the water column along the Kilindini and Port Reitz Channel varied from a

maximum of 31.0 to 28.7 °C. The vertical distribution of water temperatures was largely

uniform indicating a well mixed column. Variations along the channel indicated an increase in

temperatures towards the open sea (Station A) (Figure 7.2). Water pH varied from 7.5 to 6.8.

Water salinity expressed as NaCl % wt varied narrowly from 2.6 – 2.4.

Area - A

Area - B Area - C

Area - D

Area - E

Area - F

Area - G

121

26

27

28

29

30

31

32

A B C D E F G H I J K

Sampling Points

Te

mp

era

ture

(oC

)

2

3

4

5

6

7

8

pH

, S

alin

ity

Temp

pH

Sal

Figure 7.2: Variations of water pH, Salinity and Temperature measured along the Kilindini and Port Reitz Channel

2

3

4

5

6

7

8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Sampling Stations

pH

& S

alin

ity

25

26

27

28

29

30

31

Te

mp

era

ture

(oC

)

pH

Sal

Temp

Figure 7.3: Mean Water Temperature, pH and Salinity within the Turning Basin

An intensive sampling of the water column in the vicinity of the turning basin revealed

comparable magnitudes of pH, Salinity and Temperature (Figure 7.3). On comparing the

measurements of the parameters from the two study sites; the water temperature and salinity

were significantly different. The distribution of phosphates in the Channel and Turning Basin

is presented in Figures 7.4 and 7.5. Measurements of pH, phosphate and cadmium from the

2 sites were not significantly deferent (Table 7.1). The concentration levels of ammonia were

low (< 0.03 µmol l-1), whereas levels of nitrate/nitrite were very high (> 500 µmol l-1).

122

Dissolved levels of Hg, As and Cr were below detection limits. The results of the water

quality parameters investigated were within the range of previous studies (Adala et al., 2007).

0.00

0.05

0.10

0.15

0.20

0.25

A B C D E F G H I J K

Sampling Stations

Co

nce

ntr

atio

n (

mg

l-1)

Figure 7.4: Distribution of Phosphates along the Kilindini / Port Reitz Channel

0.00

0.05

0.10

0.15

0.20

0.25

0.30

1 3 5 7 9 11 13 15 17 19 21 23

Sampling Points

Ph

osp

ha

te &

Ca

dm

ium

(ug

l-1)

Phos Cd

Figure 7.5: Mean Concentrations of Phosphates and Cadmium in the Turning Basin

Table 7.1. Comparison of water quality parameters between the Channel and Turning Basin

123

Site Parameters

Temperature pH Salinity Phosphate Pb Cd

Channel Mean 29.43 7.26 2.45 0.19 0.08 0.16

Max 31.00 7.53 2.55 0.22 0.10 0.21

Min 28.70 6.77 2.40 0.12 0.06 0.11

SD 1.08 0.23 0.05 0.04 0.01 0.03

Turning Bay Mean 28.65 7.26 2.50 0.18

0.05 0.17

Max 30.10 7.76 2.60 0.24 0.09 0.28

Min 25.40 6.85 2.40 0.15 0.02 0.10

SD 1.11 0.23 0.06 0.03 0.04 0.04

t Test (p<0.05) different

Not different different

Not different

Not different

A number of samples were tested for contamination with microbial indicator organisms. The

results showed that 91 % of the samples analysed had coliform counts. It was realised that

the water quality with respect to coliform was acceptable for recreation purposes.

91%

9%

<10 Counts

>10 counts

Figure 7.6: Levels of coliform counts in water samples

7.2.2.2 Sediment Quality

A total of 42 sediment samples from the Navigation Channel in Kilindini creek and the

Turning Basin in Port Reitz creek were collected and analysed for Cadmium (Cd), Lead (Pb),

Mercury (Hg), Chromium (Cr) and Arsenic (As). The analytical results are summarized in

Table 7.2 and Figure 7.6.

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The concentration levels of Hg, one of the highly toxic elements with no known metabolic

function, were generally very low. The levels of Hg were considered to be environmentally

acceptable. The concentrations of Pb were medium to low and generally lower than levels

reported in earlier studies. The concentrations of Cd were generally elevated, but were

comparable to levels reported from earlier studies. Thus, Adala et al. (2007) reported Pb

levels ranging from 52 to 104 mg/kg dry wt. The concentrations encountered are comparable

to levels reported by Everaarts & Nieuwenhuize (1995), Williams et al. (1997), Kamau (2001),

Kamau (2002), Mwashote (2003) and Munga et al. (2003) (Table 7.3). The results on the

concentrations of Cr and As indicated elevation of the elements in the study area.

Table 7.2: Summary of concentrations of selected heavy metals in sediments

(Concentrations in mg/kg dry wt.)

Cd Pb Hg Cr As

Mean 5.23 26.55 0.13 146.20 46.29

Max 12.74 89.06 0.19 1445.08 85.44

Min 1.38 8.25 0.06 2.48 4.60

Std Dev 2.89 18.80 0.04 291.29 17.37

No. of Samples 42 42 42 42 31

Table 7.3: Concentrations of Cd and Pb (mg kg-1

dry wt) in sediments

Location Cd Pb Source

Continental slope and coastal zone, Kenya 0.01 - 0.12 12 – 16

Everaarts & Nieuwenhuize (1995)

Mombasa inshore waters - 1.0 - 427 Williams et al. (1997) Makupa and Kilindini creeks < 10 - 13 - Kamau (2001) Port Reitz and Kilindini creeks ND – 9.3 - Kamau (2002) Makupa and Tudor creeks ND – 1.0 0.2 – 58.0 Mwashote (2003) Ungwana and Malindi Bays 4.0 – 14.8 63.8 – 111.7 Munga et al. (2003)

125

Median

25%-75%

Non-Outlier Range

Outliers

ExtremesCd Pb Cr As

Heavy metals

0

20

40

60

80

100C

oncentr

ations (

mg/k

g)

Figure 7.7: Heavy metals in sediments from the Channel and Turning Basin

As the development of marine sediment quality guidelines (SQGs) in Kenya is yet to be

finalized, SQGs from the Centre for Environment, Fisheries and Aquaculture Science,

CEFAS, and compared with other typical guidelines from other countries were used to

evaluate the levels of particularly Cd, Pb, Cr and As (Table 7.4). The CEFAS SQGs

categorize metal concentration into 2 Action Levels. Concentrations below Action Level 1;

the sediment is considered safe for disposal at sea. Concentrations exceeding Action Level

2; the sediment is not safe for disposal at sea. Alternative disposal methods have to be

adopted. For concentration levels occurring between the 2 categories, precautionary measures

have to be taken. With reference to the CEFAS SQGs therefore the following inferences are

made (Table 7.5).

Table 7.4: CEFAS sediment quality guidelines

Metal Action Level 1 (mg/kg)

Action Level 2 (mg/kg)

Arsenic 10 25 - 50

Cadmium 0.2 2.5

Chromium 20 200

Lead 25 250

Mercury 0.15 1.5

126

Table 7.5: Assessment of the sediment quality with reference to CEFAS guidelines

Metal

Proportion (%) of samples analysed in each category Comment /

Recommendation Acceptable

quality

Action Level 1 Action Level 2

As 6.4 54.8 38.7 Containment and

Monitoring

Cd 19.0 81.0 Containment and

Monitoring

Cr 4.8 81.0 14.3 Monitoring

Pb 57.1 42.9 0 Monitoring

Hg 92.9 7.1 0 Monitoring

127

8. PUBLIC CONSULTATION AND PARTICIPATION

During the EIA process consultations were conducted with Lead Agencies and members of

the public. Key stakeholders consulted include fishermen, Non-Governmental Organisations

(NGOs) such as CORDIO, KESCOM, WCS and Lead Agencies such as Kenya Wildlife

Service (KWS), Kenya Marine & Fisheries Research Institute (KEMFRI) and the Department

of Fisheries. The lead environmental regulator, National Environment Management Authority

was also briefed on the preliminary findings of the EIA Study.

Plate 8.1: An elderly fisherman gives his contribution during the consultation stage

Key issues raised by the stakeholders include:

♦ The need to adequately compensate fishermen for loss of livelihood as a result of

interruption of fishing activities during the dredging period;

♦ The proponent was advised to develop a comprehensive monitoring procedure that

would address the adverse impacts predicted in this study report as well as impacts

that may arise during dredging but are not anticipated in the study

In addition a number of memoranda were submitted to KPA by the fishermen detailing their

proposal of how the compensation mechanism should be implemented. Details of

stakeholders meetings are as attached in the appendices.

128

9. POTENTIAL IMPACTS AND MITIGATION MEASURES 9.1 Impacts of Dredging 9.1.1 Loss of bottom habitat, shellfisheries, fisheries, fishery food sources Dredging of soft bottom can remove important bottom-living aquatic life. However this bottom

will readily be recolonized by replacement benthic organisms within a few seasons. As the

original habitat will probably have changed due to the dredging operations the new

population might differ from the original one. Simulations undertaken during the EIA study

indicate there would be no significant change in current patterns hence this impact is

expected to be minimal.

9.1.2 Water-column turbidity Fine-grained dredged material slurry discharged during open-water disposal would be

dispersed in the water column as a turbidity plume; however, the vast majority rapidly

descends to the bottom of the disposal area where it accumulates under the discharge point

in the form of a low-gradient fluid mud mound overlying the existing bottom sediment.

Under normal conditions, more than 98 percent of the sediment in the mudflow remains in

the fluid mud layer at concentrations greater than 1%, while the remaining 2 percent may be

re-suspended by mixing with the overlying water at the fluid mud surface. These conditions

may persist for the duration of the disposal operation at the site and for varying times

thereafter as the material consolidates to typical sediment density.

9.1.3 Water contamination Although the vast majority of heavy metals, nutrients, and petroleum and chlorinated

hydrocarbons are usually associated with the fine-grained and organic components of the

sediment there is no biologically significant release of these chemical constituents from

typical dredged material to the water column during or after dredging or disposal operations.

However there would be no persistently higher levels of dissolved metals or nutrients greater

than background concentrations.

9.1.4 Impacts on Port Operations

A number of these impacts already exist as a result of current port operations. However it is

expected that with completion of the dredging project more the volume of maritime traffic

would increase thereby increasing the magnitude of these impacts. Such impacts include:

129

9.1.4.1 Discharge of garbage and litter

Discharge of garbage into the waters, if not controlled will result in unsightly conditions on the

shoreline owing to accumulation of non-biodegradable materials such as plastics, glass and

metal containers. Plastic bags and sheets can block cooling water intakes or foul propellers

of vessels and small craft using the port.

9.1.4.2 Accidental Spills

Accidental spills can and do occur owing to marine casualties (collisions, groundings, fires,

etc.), failure of equipment (pipelines, hoses, flanges, etc.) or improper operating procedures

during cargo transfer or bunkering. Such spills can involve crude oils, refined products or

residual fuels, noxious liquid substances and harmful substances in packaged form.

The more volatile oils are generally less harmful to the environment because they rapidly

evaporate but they can present the hazard of fire or explosion. The more viscous oils remain

on the water surface where they will move under the influence of wind and current. Chemical

spills can also result in the introduction of water-soluble toxic substances into the marine

environment, which can have a damaging effect upon marine organisms.

9.1.4.3 Dry cargo releases

Most such releases are likely to be wind-blown particulates from vessels loading or offloading

or from waterfront deliveries. Engineering/planning should be done prior to project

implementation to determine the feasibility of requiring enclosed storage or loading/offloading

facilities. At the moment dry cargo within the port are handled by a private company, Grain

Bulk Handlers Limited who have leased berth no. 3 for this purpose. This is a state-of-the-art

bulk terminal with enclosed conveyor systems complete with dust extractors. Further, it is

expected that the effect of dry cargo releases will be minimal as the proposed berths will be

used only for container handling.

9.1.4.4 Sanitary wastes Treated and untreated sanitary wastes may be discharged to sea water from vessels and

waterfront installations. This will increase organic matter concentration in vicinal water area

which can be a main source of eutrophication processes in the adjacent waters.

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9.1.4.5 Noise from Port traffic and Terminal operations

Port activities such as clamping and loading/offloading of containers and movement of cargo

handling equipment may generate noise above levels of comfort to the operators. Noise

would also be generated by trucks hauling containers to and from port terminals. Noise level

is expected to increase with increased port cargo.

9.1.4.6 Effects of dust and other airborne emissions

Dust sources include various port operations such as construction activities, outdoor storage

of raw materials and other particulates (ranging from coal and limestone to grain and wheat

storage, for example). Smoke is expected from increased port traffic. If vehicles and

equipment are not well maintained exhaust fumes can be a safety hazard as the fumes

obstruct vision, increasing the potential for accidents. Smoke and airborne combustion

products can present problems primarily because of the potential for distributing toxic or

hazardous substances and for the greater capacity for dispersal.

9.1.4.7 Traffic burden projections

As a result of the dredging project there is expected to be an increase in containerized cargo

offloaded from the port of Mombasa, mainly from post-panamax ships expected to call at the

port. This would result into increased number of trucks at the container terminals, causing

congestion.

Additional problems include lack of sufficient parking for trucks and drivers, trucks waiting for

port access, damage by trucks to roadways, and spillages from trucks. Further there would be

secondary traffic impacts - traffic increases not directly attributable to the project but expansion

of residential, market and commercial areas due to the enlarged industrial employment base.

9.2 Oceanographic Environmental Impacts and Mitigation Measures

9.2.1 Oceanographic impacts of offshore disposal All dredged materials have a significant physical impact at the point of disposal. This includes

local covering of the seabed and local increase in suspended solids. Physical impacts may

result from subsequent transport, particularly of the finer fractions, by wave and tidal action

and residual current movements. Biological consequences of these physical impacts include

smothering of benthic organisms in the dumping area. The significance of the physical and

biological impacts largely depends on the physical conditions and natural values locally met.

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The seabed at Mombasa, including the ocean floor near the entrance of Kilindini harbor, is

characterized by a slope that gradually becomes steeper. From the proposed offshore

dumping site, the seafloor slope reaches 200 m of depth over a distance of 500 m. A depth

of over 2000 m is already reached at 10 km from Mombasa.

Disposal of the dredged material (from capital dredging) will be carried out in this area, where

the sediments will move into deep waters, and prevent a significant increase in the sediment

load in the plume. Considering the available alternatives and their possible environmental

impacts, offshore disposal of the dredged material is considered to be the most favorable

option.

Numerical modeling results from the applied dispersal models suggest that any sediment

plumes resulting from dredging operations will either be dispersed Northwards during the

south east monsoon (SEM) season and Southwards during the north east monsoon (NEM)

season. The model further predicts the magnitude and extent of turbidity. The sediment

plume dispersion is higher during the SEM as compared to the NEM period (Figures 15 and

16). The maximum values of TSS concentrations were 50 mg/l during SEM as compared to

20 mg/L during the NEM.

9.2.2 Hydrodynamics

Currents: Impacts of changes to bathymetry and the increase of the cross-sectional area of

the entrance to Kilindini harbour associated with dredging were modeled. Modeling results

indicates that sea levels will not be impacted by the dredging and that the tidal water levels

will remain almost exactly the same in the harbor. The results also indicate that there will be

no change in the current speeds in the harbor or the dredged channel after the dredging.

However, there will be a small decrease in current speeds through the entrance of the

harbour associated with the increase in the cross sectional area.

9.2.3 Waves Wave Climate: Potential impacts to tides and shoreline wave action from changes in the

bathymetry of Kilindini harbor through dredging and widening of the shipping channel were

also modeled. Results showed that changes to wave heights (increase or decrease) were

negligible (less than 10% change) as shown in Figure 9.1.

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Figure 9.1: Results of wave penetration simulation showing that change of wave heights (increase/decrease) due to dredging is negligible (less than 10%).

Modelling of wave current directions before and after the construction of the land reclamation

area at the deepening and widening of the navigation channel indicates only minor variations

in current directions. This indicates that the proposed dredging works is not likely to alter

alongshore erosion and sediment transport processes.

9.2.4 Predicted effect of the dredging project on water levels and tidal currents

It is predicted that spring tide low water levels in Kilindini harbor would be lowered by up to

20mm as a result of the effect of the channel deepening and widening on tidal propagation,

resulting in the increased exposure of intertidal areas at low water on spring tides. Figure 9.2

shows an instantaneous snap short of depth-averaged current velocity vectors generated by

numerical simulations during spring tide conditions.

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Figure 9. 2: Numerical simulation results of created current velocities vector field in Kilindini harbour including the offshore dumping site and the adjacent Tudor creek

Regarding the impact of the capital dredging works on tidal currents within Kilindini Harbor,

the following conclusions were drawn:

• The spring tide current directions are little altered, although there are corresponding

small changes to the current speed;

• Although more water is drawn into the channel during flood tide and flushed out

during ebb tide as a result of the deepening and widening, this does not necessarily

imply faster currents in the channel, given the additional cross section of the channel;

and,

• Current speeds in the deepened Turning Basin are generally reduced.

9.2.5 Predicted effect of the proposed project on ebb-dominance of the Harbour

Modeling results indicate that after the dredging works, Kilindini harbor shall still have tidal

asymmetry that remains ebb-dominant (i.e. stronger ebb currents as compared to flood

currents). This situation shall continue to favor a net export of materials (including coarse

sediments from upstream rivers) out of the harbor (see Wolanski, Jones, & Bunt, 1980;

Shetye, 1992; Mazda et al., 1995; Kitheka et. al., 2003). However, the ebb-dominance of the

harbor will not be as pronounced as during the period before the dredging. This is attributed

to more attenuation of ebb currents as compared to flood currents after dredging.

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This implies a tendency for slightly more retention of materials in the system as compared to

the present situation. In mangrove-fringed estuarine systems (such as Kilindini harbor), ebb

dominance is believed to help scour the channel (see Wolanski et al., 1992). This situation

(of reduced ebb-dominance) may require Kilindini harbor to undergo relatively more regular

maintenance dredging due to slightly faster rate of siltation.

9.3 Biological Impacts 9.3.1 Removal of sub-marine sediment and associated attached sessile organisms Nature of impact –Submarine sediments and their associated attached sessile organisms will

be physically removed from the seabed with consequential destruction of the infaunal and

epifaunal biota;

Duration – Short, recolonization is predicted to take about one year on silty clays (see Table

6.14);

Intensity – Medium, the majority of the benthic organisms are likely to die, but quite a number

will relocate by migration (Hall 1994, Kenny and Rees 1994, 1996, Newell et al. 1998,

Herrmann et al. 1999, Ellis 1996, 2000); Long-lived species, like molluscs and echinoderms

need longer to re-establish the natural age and size structure of the population (Kenny and

Rees 1994, 1996). Large burrowing species may, however, be able to persist by retreating

into their burrows.

Probability – Definite;

Status of impact – Negative;

Degree of confidence – High;

Significance – Medium, due to the short duration and medium intensity of the impact;

Mitigation – Leave some undisturbed patches (reservoirs) between the dredging areas, to

speed up recolonization and recovery. This is already implied in the works structure as

dredge areas are clearly marked and some areas will remain undisturbed.

Table 6.14: Timing for recovery of seabed habitats after dredging (after Ellis 1996)

Sediment type Recovery time

Fine-grained deposits: muds, silts, clays, which can contain some rocks and boulders

1 year

Medium-grained deposits: sand, which can contain some silts, clay and gravel

1-3 years

Coarse-grained deposits: gravels, which can contain some finer fraction and some rock and boulders

5 years

Coarse-grained deposits: gravels with many rocks and boulders

>5 years

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9.3.2 Suspended sediment effects on sessile and slow-moving invertebrates Nature of impact – Generation of suspended sediment plumes during the dredging and off-

shore dumping periods may have sublethal or lethal impacts on sessile and slow-moving

invertebrates

Duration – Medium, potential effects extend over the duration of the dredging activity

(expected to last few months)

Intensity – Low, area already under high turbidity regimes and existing organisms are

adapted to those local high turbidity levels (see Adala et al., 2008)

Probability – Definite, elevated suspended sediment concentrations are a typical by-product

of soft bottom marine sediment dredging / dumping activities

Status of impact – Negative

Degree of confidence – High

Significance – Low, due to the medium duration and low intensity of the impact

Mitigation – Not necessary in itself but reductions in the amount of suspended sediment

through use of appropriate civil technology will further reduce risks

9.3.3 Suspended sediment effects on fish Nature of impact – Generation of suspended sediment plumes in the dredging / dumping

areas may have sublethal or lethal impacts on fish and/or may result in avoidance behaviour

Duration – Medium, potential effects extend over the duration of the dredging / dumping

activites

Intensity – Low, fish are mobile and will move out of the affected area. Effects on fish vary

greatly and critical exposure levels can range from ~500 mg/l for 24 hours to no effects at

concentrations of >10 000 mg/l over 7 days (Clarke and Wilber 2000). However, direct long-

term impacts are unlikely to occur for fish as they are mobile and therefore will avoid any

area affected by increased sediment loadings and are able to return once construction

activity has ceased. Short-term impacts may occur by reducing the ability to find prey by

visual feeders (Hecht and van der Lingen 1992). On the other hand, fish may be attracted by

the ‘odour stream’ of crushed benthic organisms (Herrmann et al. 1999).

Probability – Definite, elevated suspended sediment concentrations are a typical by-product

of soft bottom marine sediment dredging / dumping activities

Status of impact - Negative

Degree of confidence – High

Significance – Low, due to short duration and low intensity of the impact

Mitigation – Not necessary in itself but reductions in the amount of suspended sediment

through use of appropriate civil technology will further reduce risks

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9.3.4 Suspended sediment effects on ichthyoplanktic stages Nature of impact – Generation of suspended sediment plumes in the dredging / dumping

areas may have an impact on ichthyoplanktic stages

Duration – Medium, potential effects extend over the duration of the dredging / dumping

activity

Intensity – Medium, some ichthyoplankton may die. Fish eggs and larvae are generally more

susceptible to elevated concentrations of suspended sediments; hatching can be delayed

and feeding of larvae may be impaired. The adhesion of particles to eggs may cause loss of

buoyancy resulting in the eggs sinking to the bottom (ICES ACME 1997).

Probability – Definite, elevated suspended sediment concentrations are a typical by-product

soft bottom marine sediment dredging / dumping activities

Status of impact - Negative

Degree of confidence – High

Significance – Low, due to the medium duration of the impact

Mitigation – Not necessary in itself but reductions in the amount of suspended sediment

through use of appropriate civil technology will further reduce risks

9.3.5 Suspended sediment effects on phytoplankton productivity and other aquatic plants Nature of impact – Generation of suspended sediment plumes in the dredging / dumping

areas may reduce the productivity of phytoplankton and other aquatic plants.

Duration – Low, potential effects extend over the duration of the dredging / dumping activity

Intensity – High, the proportion of very fine sediment is very high (over 90%) and the settling

of the material out of the photic zone will be slow. Results from a geophysical survey by

Japan Port Consultants (Chapter 5) show that organic matter in the vicinity of the turning

basin is high. This suggests that the relative concentrations of contaminants are likely to be

high. More so, due to high concentration of organic matter in the sediments nutrient

concentrations in pore waters are likely to be moderate to high and therefore risks of

eutrophication due to introductions of nutrients to the water column are considered to be

moderate, but this effect is likely to be offset by high uptake rates in the otherwise

oligotrophioc Indian ocean waters.

Probability – Definite, elevated suspended sediment concentrations are a typical by-product

soft bottom marine sediment dredging / dumping activities

Status of impact – Negative

Degree of confidence – High

Significance – low, due to the low duration and high intensity of the impact

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Mitigation – Not necessary in itself but reductions in the amount of suspended sediment

through use of appropriate civil technology will further reduce risks.

9.3.6 Depletion of water column oxygen concentration Nature of impact – Potential depletion of water column oxygen concentration through

bacterial decomposition of remobilised organic matter in the works area over the dredging /

dumping period.

Duration – Medium, potential effects extend over the duration of the dredging / dumping

activity

Intensity – Medium, organic matter concentration in the sediments are moderately high, but

tidal movements helps in aiding water mixing. Moreover, the bottom waters in Port Reitz bay

are usually well oxygenated (Chapter 7), and the organic matter suspended in the plume is

likely to be medium due to the moderate POC concentration in the sediments (Chapter 7).

Similarly, due to moderate amounts of POC in the sediments nutrient concentrations in pore

waters are likely to be moderate, but risks of eutrophication due to introductions of nutrients

to the water column are considered to be low because of effective mop up by primary

producers.

Probability – Improbable, medium organic matter concentration in the sediments

overshadowed by tidally-driven water column mixing and biological mop-ups

Status of impact - Negative

Degree of confidence – High

Significance – Low, due to low likelihood

Mitigation – Not necessary in itself but reductions in the amount of suspended sediment

through use of appropriate dredging technology will further reduce risks

9.3.7 Noise during dredging / dumping activities Nature of impact – Noise from the dredging / dumping activity may disturb some marine

mammals. But in the worst-case scenario the noise impact has a potential radius of few

hundred metres from the source

Duration – Medium, potential effects extend over the duration of the dredging / dumping

activity

Intensity – Low, sensitive mammals do not use these shallow areas; in the worst-case

scenario, marine mammals have a wide distribution range and should move away from

source of noise;

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Probability – Probable, depends whether any marine mammals may migrate towards the

source of noise

Status of impact – Negative

Degree of confidence – High

Significance – Low, due to low intensity

Mitigation – Not necessary due to low significance

9.3.8 Sedimentation on subtidal muddy and sandy habitats Nature of impact – Settling of material from construction works may smother benthos on

subtidal muddy and sandy habitats adjacent to the dredging / dumping sites

Duration – Medium or long, recovery can take from <1 year (muddy habitats) up to 3 years

(sandy habitats)

Intensity – Medium, depending on the sediment layer thickness many organisms may burrow

to the surface through the deposited sediment and many filter-feeders are highly adaptable

to increased sediment loads

Probability – Definite

Status of impact - Negative

Degree of confidence – High

Significance – Low, due to the small extent of the impact

Mitigation – Not necessary due to low significance

9.3.9 Oil spill effects on mangroves and seabirds due to coating Nature of impact – Accidental and/or operational oil spills form vessels during dredging /

dumping periods or during the operational phase may affect mangroves and seabirds due to

oiling

Duration – Very long term, due to (1) potential damage to mangroves which takes several

decade-years to clean, and (2), potentially reduced breeding success of seabirds

Intensity – High, (1) oil-smoothed mangroves die and so do their ecosystem services, and (2)

seabirds die or their breeding success is reduced and this may have international

implications

Probability – Unknown, no predictions are made for the likelihood of increases in oil spill with

increased ship traffic or for possible accidents during dredging

Status of impact – Negative

Degree of confidence – High

Significance – High, mangroves and birdlife thereon are protected in Kenya (mangroves –

Kenya Forest Service; Birds – Kenya Wildlife Service and National Museums of Kenya), and

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impacts on them have international implications through the Biodiversity Convention,

Important Birdlife Areas, and IUCN conservation classification

Mitigation – Through KMA’s and KPA’s port and shipping regulations, and best practice

procedures in place, seek to reduce probabilities of accidental and/or operational spills

through enforcement of vessel traffic and oil spill management systems. However, due to

devastating effects of even one large spill significance would remain high but mitigation can

help reduce probabilities of accidents

9.3.10 Oil spill affects on marine life and habitats Nature of impact – Accidental and/or operational oil spills from vessels during dredging /

dumping and the operational phase may affect marine life due to direct toxic effects and/or

habitat alteration.

Duration – Medium (but chronic)

Intensity – Low

Probability – Probable

Status of impact – Negative

Degree of confidence – Medium

Significance – Low, most of the potentially affected organisms are widely distributed in the

region

Mitigation – Through KMA’s and KPA’s port and shipping regulations, and best practice

procedures in place, seek to reduce probabilities of accidental and/or operational spills

through enforcement of vessel traffic and oil spill management systems. However, due to

devastating effects of even one large spill significance would remain high but mitigation can

help reduce probabilities of accidents.

9.3.11 Other spills from containers and their effects on marine life Nature of impact – Potential accidental spills from containers containing hazardous

substances reach the sea and may affect marine organisms

Duration – Unknown, depends on the substance

Intensity – Unknown, depends on the substance

Probability – Probable

Status of impact – Negative

Degree of confidence – Low, due to the unknown extent, duration and intensity

Significance – Unknown, depends on the substance

Mitigation – A management plan on how to deal with containers with hazardous substances,

which also incorporates plans for emergencies, should be in place

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9.3.12 Spills from operational machinery and their affect on marine life Nature of impact – Potential accidental spills from operational machinery, which could

include hydrocarbons such as hydraulic fluids, may affect marine organisms

Duration – Unknown, depends on the substances and the amount

Intensity – Unknown, depends on the substances and the amount

Probability – Probable

Status of impact – Negative

Degree of confidence – Low, due to the unknown extent, duration and intensity

Significance – Low, when good management plan in place

Mitigation – Detailed management plan should be in place

9.3.13 Ship wastes effect on marine life Nature of impact – Potential waste from ships berthed at the container terminal may affect

marine organisms

Duration – Unknown, depends on the waste

Intensity – Unknown, depends on the waste

Probability – Improbable, when regulations of no discharge are followed

Status of impact – Negative

Degree of confidence – Low, due to unknown duration and intensity

Significance – Low, when regulations of no discharge are followed

Mitigation – Not necessary when regulations are policed

9.3.14 Discharge of ballast water introduces alien species Nature of impact – A rise in discharge of ballast water in the harbour due to increased

shipping as a response to the berthing of ships may increase the risk of introduction of

marine exotic species

Duration – Unknown, depends on the introduced organisms but likely to be very long term or

permanent when an introduced alien becomes invasive

Intensity – Unknown, depends on the introduced organisms

Probability – probable, given that there is no policy of management of ballast water in Kenya

(plans are under way to establish some through KMA and IMO’s initiatives)

Status of impact – Negative

Degree of confidence – Low, due to unknown duration and intensity

Significance – Medium, no policy of management of ballast water in Kenya

Mitigation – Abide by the interim provisions of the Management of Ballast Waters in Port

states currently under development by IMO

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9.3.15 Synergistic (cumulative) impacts Since the construction of the Mombasa harbour, the shoreline of the Port of Mombasa and its

natural resources has already been significantly modified by many dynamic forces acting on

sediment and water interfaces. Any further, even slight changes in the sediment distribution

may therefore have a cumulative impact, resulting in a complete change of the

morphodynamics and consequently the associated biota. At present, the pollution status of

Port of Mombasa do indicate high build-ups of some contaminants in some places (see

Everaarts & Nieuwenhuize 1995, Williams et al., 1997, Kamau 2002, 2005, this study chapter

7), suggesting that most communities in the Port Reitz area are not impacted by pollution.

The increase in the number of containers handled at the KPA terminals with associated

increased risk of spills during operation could result in higher pollution input into Port waters,

which, in addition to the existing input from storm water, river and municipal waste

discharges may eventually lead to the contaminants reaching levels of concern.

9.3.15 Potential negative impacts specific to coral gardens and Mombasa Marine Reserve

A plume modeling from the hydrodynamic exercise indicates that during the south east

monsoon, the plume direction moves northwards and into parts of the marine protected area.

However, the deleterious plume of over 50mg/l is not expected to move into the coral reef

areas. The model predicts the plume with total suspended solids of 50mb/l will be limited to

depths beyond 50m contour for most of the time. However, other deep sea communities may

still be temporarily affected. These include:

a) 16 taxa grouping of fisheries listed in the KWS-CORDIO monitoring schedule (Table

6.10)

b) 10 taxa grouping of invertebrates listed in the KWS-CORDIO monitoring schedule

(Table 6.11)

c) Potential IUCN listings of endangered species including sharks, turtles, dugongs, that

may be using these areas (Table 6.10 – 6.12)

Baseline surveys of these key habitats have been undertaken (this EIA study, other

monitoring programs). In addition we suggest that in situ turbidity loggers be employed at

reef slope stations so as to monitor the levels of turbidity throughout the dredging / dumping

process. This information will also used to derive key habitat tolerances.

Routine biological monitoring and a Coral Condition Monitoring Program that includes pre-

dredging / dumping condition of benthic habitats and communities should be undertaken and

supported. Coral colonies should be routinely assessed for changes in % bleaching and %

partial mortality to ensure warning or shutdown habitat trigger values are not exceeded.

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9.4 Chemical Impacts The results of the analysis of surficial sediments from the Navigation Channel in Kilindini

creek and the Turning Basin in Port Reitz indicate significant contamination with

environmentally toxic heavy metals Cd and As. Contamination by the 2 metals is more

pronounced in the Turning Basin which has sediments composed of relatively high levels of

silt and mud associated with high organic matter. The high levels of Cd and As in sediments

from the Turning Basin is attributed to anthropogenic sources, especially, the wastewater

discharge from the municipal sewage treatment facility at Kipevu. It is therefore

recommended that the contaminated dredged material should not be disposed at sea.

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10. ENVIRONMENTAL MANAGEMENT PLAN

Environmental Management Plan proposed in this study consists of:

Mitigation

Monitoring

10.1 Mitigation Measures

Mitigation refers to formulation and implementation of measures to ensure that adverse

environmental impacts are eliminated or minimised to acceptable levels

Mitigation Measures may be:

Engineering – Incorporated into project design

Management – Monitoring, Evaluation, Review

10.1.1 Mitigation measures for dredging impacts Dredging and disposal of dredged materials are primary sources of water quality degradation

during construction stage.

10.1.1.1 Dredging work - General Taking account of proposed dredging methods/equipment, hopper dredger for access

channel and grab dredger for turning basin, no significant increase of surrounding water

turbidity is expected. However, if unacceptable level of suspended solid (SS) concentration is

monitored around the dredging site, following measures will be taken immediately:

• Restrict overflow operation during dredged material loading

• Reduce dredging volume per day

• Installation of silt protection curtain surrounding grab dredger

• Use special dredging equipment to minimize agitation of bed material if the material is

significantly contaminated.

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10.1.1.2 Disposal of dredged materials Dredged materials will be disposed at designated open water dumping site keeping a

distance more than 3km from biological sensitive areas, such as existing coral reef, sea

grass bed and Mombasa Marine National Reserve. Disposal period will be mainly during SE

Monsoon Season (from April to September) considering preferable local current system

which could avoid significant impacts on the biological sensitive areas due to turbid water

dispersion from the dumping site.

According to the simulation exercise we carried out of turbid dispersion conducted in the EIA,

turbid water column will not reach beyond 3 km from the dumping location. However, if

unacceptable level of SS concentration is measured at the monitoring points which are

placed at said biological sensitive areas, following measures will be taken immediately:

• Reduce disposal volume per day

• Relocate dumping site further offshore

In case at any time the monitoring exercise indicates that the dredged material is

unacceptably contaminated, thus can not be disposed at the offshore dumping site, the

material will be disposed at a land based dumping site in Port Reitz area (at the site of the

proposed container terminal) with proper care and containment facilities.

10.1.1.3 Effluent discharge from calling ships On commissioning of the dredging project increased number of ships will call at the port.

Prior to permitting the ships to offload cargo, KPA will inspect the ships and/or liaise with the

ship administration to establish weather there is any waste on board. Any waste found will be

received at the designated facilities such as East Africa Environment Company (EAM).

10.1.1.4 Accidental oil spill The most potential occasion involving the oil spill is ship collision and landing. This risk will

be raised by increased number of water traffic due to operation of new container terminal. In

order to decrease the risk, following measures will be taken:

• Evaluate future traffic volume for design of sufficient port facilities

• Ensure operation in line with the ship handling manual. The manual has been designed

specific to the Port of Mombasa by Japan Marine Science Inc on behalf of KPA. KPA

pilots were part of the design and will be trained after the proposed dredging works

• KPA will install new navigation buoys and leading lights to allow for safer navigation of

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the channe

• Special short-based radar and/or reflectors will be installed for safe navigation and

collision avoidance

• Updated pilot qualification or additional training will be undertaken

• Additional tugs, lighters and mooring and pilots requiring special skills will be made

available.

In order to respond to possible accidental oil spill, the Port of Mombasa already has an

emergency response program. This emergency contingency plan will be enhanced to the

proposed dredging project, clearly indicating authority and responsibility for dealing with such

incidents. Reporting and altering mechanism will established to ensure that any spillage is

promptly reported to the Port Authority.

In addition, specialized oil spill response equipment will be available to deal with small to

medium spillages. This equipment will include containment booms, recovery devices, oil

recovery or dispersant application vessels. The equipment operators will be trained in

deployment of the equipment, and the contingency plan regularly exercised to test reporting

and altering procedures.

During dumping the material will be released at sea bottom to minimise plume

generation;

Fishers to be provided with motorised boats to enable them fish further offshore

during the dredging period

Monetary compensation for fishers to assist in restoration of livelihood lost during

dredging

Continuous monitoring during dredging to ensure contaminated sediments are

captured and dumped at appropriate sites.

10.1.2 Mitigation measures for biological impacts

10.1.2.1 Mitigation for fisheries impacts The fishery in terms of biomass, abundance and diversity and sizes is inadequate and for

this study catch data was used to quantify the fishery loss in the short term and long term

effects. Indirect effects (food web) during dredging and dumping period could not be

estimated and therefore monitoring of the fishery is suggested.

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The fishers will not be able to fish during this dredging period hence compensation is relation

to loss of commercial fish catch loss should be considered. Access to the fishing grounds

after dredging should be allowed and a fishing plan to be developed. Fishers should be

empowered to access other fishing grounds. Fishermen within the creek should be supported

to explore alternative sources of livelihoods such as aquaculture.

Biodiversity monitoring should continue during dredging and dumping and should include the

threatened species. Mitigations relating to water column turbity and contamination that may

affect resident slow motile or benthic flora and fauna arising from dredge works, reclamation

and disposal of dredged materials and other operational activities have already been

addresses in sections above.

During public consultation an array of issues were raised by fishermen that go beyond the

TOR for this study. To adequately address all fisheries issues KPA would develop a

compensation action plan (CAP) that would come up with timelines and amounts due to all

the fishers affected. KPA intends to complete this study by end of second quarter of this year.

10.1.1.2 Hindrance of Sea Turtle migration The dredging operation will not affect directly beaches but may hinder sea turtle migration

route to those beaches. However, according to Kenya Sea Turtle Conservation Committees

(KESCOM), their migration routes and periodicity here are rare events. But nevertheless, in

such circumstance a Turtle Exclusion Device (TED) may be a possible mitigation measure.

10.1.1.3 Re-location of rare species before dredging if found During the entire phase of the project, a number of species which are known to be rare,

threatened, or endangered will be given particular attention. Whenever encountered these

species will be carefully relocated to other similar biotopes if on the path, or the project phase

will need to be temporarily halted (time-out) to allow the rare / endangered / threatened

species time for migration/reproduction/ completion of their natural life cycle.

10.1.2.4 Monitoring of state of the environment of the key critical habitats Environmental assessments of critical habitats (corals, seagrass beds, and mangrove areas,

and including mudflats) will be undertaken for purposes of monitoring changes in biological

communities which may be impacted by the project works.

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Summary of Mitigation measures for biological impacts

Impact Mitigation

Removal of sub-marine sediment and associated attached sessile organisms

Leave some undisturbed patches (reservoirs) between the dredging areas, to speed up recolonization and recovery. This is already implied in the works structure as dredge areas are clearly marked and some areas will remain undisturbed. Use of appropriate engineering technology reductions in the amount of suspended sediment

Suspended sediment effects on fish, sessile and slow-moving invertebrates

Reductions in the amount of suspended sediment through use of appropriate engineering technology will further reduce risks

Suspended sediment effects on phytoplankton productivity and other aquatic plants

Reductions in the amount of suspended sediment through use of appropriate engineering technology will further reduce risks

Depletion of water column oxygen concentration

Reductions in the amount of suspended

sediment through use of appropriate

dredging methods will further reduce risks

Noise during dredging / dumping activities

Not necessary due to low significance

Sedimentation on sub-tidal muddy and sandy habitats

Not necessary due to low significance

• Oil spill effects on mangroves and seabirds due to coating

• Oil spill affects on marine life and habitats

Through KMA’s and KPA’s port and shipping regulations, and best practice procedures in place, seek to reduce probabilities of accidental and/or operational spills through enforcement of vessel traffic control and oil spill management systems. Oil Spill Mutual Aid Group (OSMAG), an initiative of KPA and stakeholders in the oil industry is expected to play a major role in emergency preparedness.

Potential accidental spills from containers containing hazardous substances reach the sea and may affect marine organisms

A management plan on how to deal with containers with hazardous substances, which also incorporates plans for emergencies, should be in place.

Discharge of ballast water introduces alien species

Abide by the interim provisions of the Management of Ballast Waters in Port states currently under development by IMO

Potential negative impacts specific to coral gardens and Mombasa Marine Reserve

Routine biological monitoring and a Coral Condition Monitoring Program that includes pre-dredging / dumping condition of benthic habitats and communities should be undertaken and supported.

148

10.1.3 Mitigation measures for chemical impacts The method of disposal to be used is containment of the contaminated sediments. The

contaminated sediments would therefore be disposed in a containment facility to be

constructed at the site of the proposed container terminal project in Port Reitz. With this

arrangement the contained material would also act as landfill for the reclamation site as

shown below.

It is further recommended that a monitoring program be put in place to ensure that

contaminated sediments are not inadvertently disposed at sea, but are captured and

disposed at the above mentioned site.

10.1.4 Mitigation measures for oceanographic impacts Mitigation options in case of high turbidity levels include setting up of continuous monitoring

stations during the entire dredging period. It is important to note that continuous monitoring

stations be set to monitor turbidity levels at ten (10) selected locations (especially at the

Mombasa Marine Park and nearby sensitive habitats such as coral reefs) during the dredging

period in order to adopt the necessary mitigation measures and further validate the model

results. Monitoring of turbidity levels during the dredging period will assist to adopt the

necessary mitigation measures which include reducing the frequency of offshore disposal of

dredged materials until turbidity levels drop to acceptable limits.

149

10.2 Monitoring Plan Monitoring in an EIA Study refers to continuous assessment of environmental or socio-

economic variables by the systematic collection of specific data in time and space and

evaluating the data to confirm whether the proposed mitigation measures effectively address

the project impacts.

Monitoring in this study includes:

Baseline Monitoring – This has been undertaken prior to implementation;

Compliance Monitoring – To be undertaken during construction and operation and

comprises of:

Impact and Mitigation Monitoring

Work In Progress - Expense Tracking, Implementation Timelines

Monitoring in this project would follow the following characteristic loop:

Figure 10.1: Monitoring scheme

The key parameters proposed for monitoring are in Table as follows:

150

Table 10.1: Parameters for monitoring

IMPACT ResponsibilityFrequency Parameter Target

Water Quality

KPA Contractor

2 x a day during dredging works

Turbidity, Temp, Salinity, pH

+10 mg/L – Offshore +50 mg/L – Port

Water Quality

KPA Contractor

Monthly COD, DO, Nutrients

Ditto

Sediment Quality

KPA Contractor

Before Dredging

Hg, Cd, Pb, PSD World Bank Levels

Air Quality KPA Contractor

Biannually CO2, O2, H20, NO2, CO, SO2

Ambient

Fishing Constraints

KPA Contractor Fisheries

Department

Before Works

Compensation & Recovery

Completed

Abundance of Eco-systems

KPA Biannually Presence & Abundance

Maintained or Improved

In addition the following specific mitigation measures require keen monitoring:

Table 10.2: Monitoring of mitigation measures

Mitigation Measure Responsibility Stage

Provision of Fishing Boats

KPA During Construction & Operation & after

Beach Management Unit (facilitation & creation)

KPA/ Fisheries During Operation of New Container Terminal

Provision of Landing Site

KPA During Operation of New Container Terminal

Measurement of Bio-diversity Richness (fish, coral and other species)

KPA/ Contractor Before, during and after construction

151

10.3 Environmental Management Plan for the Construction Stage The Contractor shall prepare and submit the Environmental Management Plan (EMP) as a

method statement to the Engineer for his approval within 30 days of the Contractor receiving

the Letter of Acceptance.

The EMP shall address potential environmental impacts, mitigation measures, and

monitoring activities associated with dredging and dumping, and any other activities identified

by the Engineer.

The EMP will be designed to protect the following:

1) Water quality - this includes nearby beaches, fisheries/aquaculture resources, and

ambient water quality immediately outside the construction area, and

2) Coral reefs near the outer dredging area and offshore dumping area, and

3) Any other sensitive environmental areas identified by the Engineer

The EMP shall follow the mitigation and monitoring guidance for activities identified in the

EIA Report.

As the EMP is a management tool for the Contractor’s use, it shall present in detail how

these measures should be operated, the resources required, and the schedule of

implementation. The general format of the EMP shall be:

a. Objective

b. Work Plan

c. Implementation Schedule

d. Human Resources (organization chart, skill/experience of environmental staff)

e. Monitoring Schedule

f. Monitoring Location and Items

g. Monitoring Frequency

h. Others

The Contractor shall not commence any construction activities that may impact the

environment (e.g. dredging, blasting, and dumping) until the Engineer issues approval for the

EMP Method Statement.

152

The Engineer reserves the right to levy fines, restrict payment, or stop construction activities

at any time during the Contract period should the Contractor: 1) commence dredging,

blasting, reclamation or dumping activities prior to receiving an approved EMP Method

Statement; or 2) fail to adequately implement any part of the EMP Method Statement during

the course of construction activities.

10.4 Environmental Monitoring Survey The Project’s environmental monitoring program shall be detailed and approved. Monitoring

surveys shall be carried out in accordance with the proposed and approved EMP during

construction Period.

The monitoring parameters shall include, but not be limited to: Water Quality

Turbidity (NTU)

Temperature

Salinity

Conductivity

Current speed/direction

Wind speed/direction

Rain/Sun

Fecal Coliform (CFU/MPN)

Total suspended solids

Sediment settling rate

Cadmium

Lead

Iron

Zinc

Dredging Qualities

Cadmium

Lead

Iron

Zinc

Copper

Oil

153

Biological Quality

Sediment settling rate on nearby coral reefs

Changing in living coral covers on nearby coral reefs

The Monitoring surveys shall be carried out by the experienced and qualified monitoring

team. The experience and qualification of the team members will be submitted to the

Engineer in writing for approval prior to commencement of the monitoring program.

Monitoring Locations shall be indicated on a map include, but not be limited to:

1) The offshore dumping area;

2) Coral reefs nearby the dumping area;

3) Outer access channel dredging area;

4) The inner access channel, turning basin, mooring basin and berthing basins

dredging areas.

Result of the turbidity surveys during dredging operation shall be submitted daily to the

Engineer

The Monitoring Reports shall be submitted to the Engineer within 21 days of completion of

each survey. The reports shall contain:

a. Title page

b. Table of contents

c. Introduction

d. Update of priority issues identified in last month’s report

e. Results of this month report/graphs to compare results with previous months.

Results should be analysed and graphed using statistical tools (such as mean, one and two-

tailed t-tests) from Microsoft Excel or another suitable statistical package.

Summary of priority issues in this monitoring period. Priority issues should be determined in

part by: 1) comparing data with national (TCVN) standards or standards accepted by other

countries or international organizations and/or 2) significant trends identified by the

aforementioned statistical analyses.

154

10.5 Contractors Pollution Control Measures The Contractor shall provide the necessary pollution control measures in case the following

adverse environmental concerns are encountered with:

(1) When the silt content (fine materials passing #200 sieve) being disposed into the offing

reaches 2,000 PPM

(2) When the dispersion of silt content in the vicinity of dumping areas averages 1,000 PPM

over any six consecutive hour measurement; and

(3) When the dispersion of silt content reaches a maximum of 500 PPM within a radius of

250 meters from the point of dumping of dredged material into the dumping areas.

(4) The Contractor shall undertake the necessary measurements to determine the

occurrence of any of the foregoing adverse environmental consequences and should

any of the above be encountered, anti-pollution control measures including the provision

of net to contain the dispersion shall be provided by the Contractor at his own cost as

part of and incidental to the dredging activities.

155

11. RECOMMENDATIONS AND CONCLUSION

This study report has established that the proposed project would bring a number of positive

benefits to the proponent, the country and indeed the entire region including the landlocked

countries such as Rwanda, Burundi, Southern Sudan and the Democratic Republic of Congo

that depend on the Port of Mombasa for sea-bound trade. Such benefits include boost in

trade and employment creation for the region suffering from large percentages of

underemployment.

However adverse negative impacts have also been identified in the study including

temporary disruption of fishing activities during the dredging period, turbidity of water column

as a result of release of sediments (particulate) during dredging and offshore dumping and

interference with normal port operations such as docking of ships and ferries plying

passengers across the Likoni channel.

Mitigation measures have been proposed such as such as use of appropriate dredging

methods to minimize physical impacts. To mitigate against loss of fishers’ livelihood the

proponent shall arrange a compensation package for fishermen who lose their livelihood

during the course of the project. Such compensation includes provision of motorized boats to

enable fishers venture further offshore and/or monetary support for the affected fishers.

A detailed monitoring programme has been prepared to assist in tracking the progress of

implementation of the environmental management programme. This study therefore

recommends that the proposed project be approved subject to implementation of the

proposed environmental management and monitoring plan.

156

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162

APPENDICES

163

APPENDIX I

Simulation Model of Diffusion of SS and Sedimentation of Dumped Soils.

The simulation model is a three-dimensional model, or “two-dimensional multi-layer

unsteady level model,” which has three layers vertically, employing Navier-Stokes’ equation

of motion and the equation of continuity of fluid water.

(1) Equations of Continuity

( )

−

−=−−=

⋅⋅⋅⋅⋅⋅⋅⋅=−−=

=

∑∑

−

k

k

k

k

kkkk

K

Ny

Mxt

ory

N

x

MW

t

Kky

N

x

MWW

W

∂

∂

∂

∂

∂

ζ∂

∂

∂

∂

∂

∂

ζ∂

∂

∂

∂

∂

111

1 4,3,2

0

(2) Equations of Motion

“x-direction”

( ) ( )

[ ]

1,,1

01

11

2

1~

+−

−=−−=

−+

+

+

−+

++−−−=

kkx

kkx

ky

kx

kkkx

k

k

kHkzHkz

kkkkk

y

M

yx

M

x

xghP

h

NfUWUWy

VM

x

UM

t

M

τρ

τρ∂

∂ν

∂

∂

∂

∂ν

∂

∂

∂

ρ∂

ρ

∂

∂

∂

∂

∂

∂

“y-direction”

( ) ( )

[ ]

1,,1

01

11

2

1~

+−

−=−−=

−+

+

+

−+

−+−−−=

kky

kky

ky

kx

kkky

k

k

kHkzHkz

kkkkk

y

N

yx

N

x

yghP

h

MfVWVWy

VN

x

UN

t

N

τρ

τρ∂

∂ν

∂

∂

∂

∂ν

∂

∂

∂

ρ∂

ρ

∂

∂

∂

∂

∂

∂

where mass transport at each level, Ｍ，Ｎ, are expressed by the following equations:

∫∫ ==hk

khk

k VdzNUdzM ,

Expression of Pressure Term

Pressure term can be expressed as follow:

“x-direction”

164

[ ] ( )

[ ] [ ] ( )2~~

1~

111

11

≥−=

=−=

−−− k

xhgPP

kx

gP

kkkxkx

x

∂

ρ∂

∂

ζ∂ρ

“y-direction”

[ ] ( )

[ ] [ ] ( )2~~

1~

111

11

≥−=

=−=

−−−

ky

hgPP

ky

gP

kkkyky

y

∂

ρ∂

∂

ζ∂ρ

Expression of Stress at Each Layer

The stress at each layer can be expressed as follows:

Viscosity stress of wind over the water surface:

2221,0

2221,0

1

1

1

yxyaa

y

yxxaa

x

WWW

WWW

k

+=

+=

=

γρ

ρτ

ρ

γρ

ρτ

ρ

Viscosity stress between layers:

( ) ( ) ( )

( ) ( ) ( )21

211

2,1

21

211

2,1

1

1

kkkkkkikk

y

kkkkkkikk

x

VVUUVV

VVUUUU

kk

−+−−=

−+−−=

=

−−−−

−−−−

γτρ

γτρ

Viscosity stress on the sea bottom:

222

222

1

1

kkkbbottomy

kkkbbottomx

VUV

VUU

Kk

+=

+=

=

γτρ

γτρ

where the variables and symbols are as follows:

U,V,W： Velocity components in ｘ，ｙ，and ｚ directions （ｃｍ/ｓ）, ζ： Amplitude from the means surface to the actual surface （ｃｍ）, Ｈ： Water depth from the mean surface to the bottom （ｃｍ）, ρ： Density of sea water （ｇ/ｃｍ3）,

f0： Coriolis’ parameter （１/ｓ）,

g： Gravity （ｃｍ/ｓ2）,

Vx,Vy,Vz： Viscosity coefficient in ｘ，ｙ，and ｚ directions （ｃｍ2/ｓ）,

Kx,Ky,Kz： Viscos mass diffusion coefficient in ｘ，ｙ，and ｚ directions （ｃｍ2/ｓ）,

Wx,Wy： Wind velocity in ｘ and ｙ directions,

165

ρa： Density of air, γa2： Friction coefficient on the sea surface, γi2： Friction coefficient between layers, and γb2： Friction coefficient on the sea-bottom.

References:

Japan Society of Civil Engineers: “Formula of Hydraulics,” 1999

Port & Harbour Research Institute: “Technical Manual for Environmental Assessment in

Ports and Harbors,” Report of P&HRI No.3, Vol. 22, 1983

166

APPENDIX 2: MINUTES OF FINAL PUBLIC CONSULTATION EIA FOR DREDGING OF THE ACCESS CHANNEL AT PORT OF MOMBASA`-`MINUTES OF STAKEHOLDERS FORUM HELD AT ROYAL COURT ON 18th NOVEMBER 2008. PRESENT

NAME FIRM REPRESENTED CONTACT ADDRESS

TELEPHONE NUMBER

1 Patrick Gwada

Heztech Consulting Engineers P.O Box 42269 Mombasa

0722 881802

2 Khamis Mwinyikai Chairman-Beach Management Unit-Port Reitz

0722 833791

3 Dr. Charles Magori

Heztech Consulting Engineers P.O. Box 81651 Mombasa

0722985303

4 Omar Bakari Suya

Beach Management Unit- Mtongwe

P. O Box 16000 Mombasa

0722867336

5 Abdulrahman Suleiman

Beach Management Unit- Likoni

Mombasa P. O Box 96058

0721731095

6 Rose Machaku WCS P.O. Box 90681 Mombasa

0723855340

7 Devan Meseve KESCOM - -

8 Dan Abuzo KPA P.O. Box 95009-80104 Mombasa

0725634888

9 Joan Kawaka WCS P. O Box 99470 Mombasa

0721933925

10 Eng. Alfred Masha

KPA P.O. Box 95009 -80104 Mombasa

0722318404

11 Grace Wendy KWS P.O. Box 82144 Mombasa

0725308558

12 Julius Maghanga KPA P.O. Box 95009 -80104 Mombasa

0721787587

13 Francis K Kombe KPA P.O. Box 95009 -80104 Mombasa

0721820335

14 Hezekiah Adala Heztech Consulting Engineers P.O Box 42269 Mombasa

0722752696

15 Nuru Bwanakombo

KPA P.O. Box 95009 -80104 Mombasa

0722672946

16 Martha Mukira Fisheries P. O Box 90423 Mombasa

0722579117

167

17 Elizabeth Mulwa Fisheries P. O Box 90423 Mombasa

0722326826

18 Joseph Maina WCS P.O. Box 90681 Mombasa

0722883021

19 Maurice Otieno NEMA - Coast P. O Box 80078 Mombasa

0733740133

20 Michael Okumu BAC Engineering & Architecture Ltd

P. O Box 61231-00200 Nairobi

0726 850312

21 Solomon Mwangi BAC Engineering & Architecture Ltd

P. O Box 61231-00200 Nairobi

0722993761

22 Lilian Mabonga BAC Engineering & Architecture Ltd

P. O Box 61231-00200 Nairobi

0720 401046

Agenda:

• To discuss the findings and Impacts of the EIA study.

• To get opinions and comments of various stakeholders on how the dredging works

might affect them.

• To collate opinions of all stakeholders into the final report.

Presentation Summary.

• Eng. Masha (chairman) justified the dredging project as part of the development projects

of the ministry of transport.(see slides)

• Mr Adala did his presentation-(see slides)

• Mr. Gwada did his presentation (see slides)

Issues Arising from the Presentation:

• Mr. Mwinyikai wanted to know how exactly the compensation package will be

implemented.

• Mr. Adala responded to Mr. Mwinyikai stating that KPA will meet with the fisheries

department to agree. He also said that KPA had suggested the fishermen to start deep

sea fishing in which they will be trained and provided for boats too.

• Mrs. Mukira pointed out that the presentations made by the various stakeholders did not

incorporate solutions that were actually deliverable. They wanted to know the master plan

of the whole Kilindini area. In part of the deliverable, she suggested implementation to be

168

in phases as long as it is done right. She also suggested that the social aspect of the

families especially the fishermen being affected should be looked into.

• Mr. Abdularahman Suleiman wanted to know how:

The dredging commencement date

Their compensation after dredging. And of the families affected by dredging.

• Mr. Adala suggested that Mrs. Mukira elaborates on the deliverables she wants to

see in details.

• Mrs. Mukira elaborated by saying they need information on how much land they are

losing each year, amount of soil lost and the mangroves too. She further said they

had given KPA a document with their suggestions which need to be merged with the

consultants view. She also suggested that KEMFRI be given the task of looking into

future dredging.

• Mr. Adala suggested that the whole of Kilindini area undergo a Strategic

Environmental Assessment for the whole Ecosystem which will then be

comprehensive but the task assigned to the consultants involved doing only an

Environmental Impact Assessment.

• In response to the fishermen’s concern about sharing boats and not having

knowledge on deep sea fishing, Eng. Nuru explained that the boats will be provided

for fishermen in groups of about eight and training will also be availed to them by the

Japanese who are financing the loan.

• Mr. Kombe explained that the JBIC agreement was that the fishermen be given boats

and even the amounts for the resettlement are already known. KPA and the

stakeholders had come up with a plan which has already been approved by JBIC and

the compensation package will be monitored by the consultants.

• Mr. Adala also explained that the compensation package had incorporated all

stakeholders and the agreement had been reached on the compensation package.

• Mr. Kombe acknowledged the need to do a Strategic Environmental Assessment

which he suggested be incorporated into the master plan. He concurred with Mrs.

Mukira that a study be done around the new container terminal. He also suggested

that anyone who feels has been left out of the consultations has room to be

incorporated and that further consultations will be taking place.

• Mr. Dan Abuzo gave a positive Impact of the Dredging in relation to Dr. Makori’s

presentation where it was Dr. Magori said that during the high tides during dredging

169

the water will be deeper by about 2.3 M which is a good depth for more fish which

can be a god thing for the fishermen-more fish.

• Dr. Magori explained that water and sea materials come in during dredging and go

out during ebbing therefore there is a net effect on the sea level and the dirt too.

• Mr. Kombe suggested that the vessels used during dredging should be in a way that

they are careful not to dump the dredged material in areas that are not deep enough.

• In response, Mr. Adala explained that the dredgers will be environmental compliant.

He explained that the consultants will make sure the NEMA requirements are being

followed.

• Mr. Okumu explained that the consultants had already put into considerations the

types of dredgers, and the dumping method which will be environmental compliant

and by NEMA standards.

• Mr. Kombe suggested that all material whether contaminated or not should be

subjected to treatment.

• Mr. Adala in response to Mr. Kombe’s suggestion explained that hard materials had

no evidence of contamination. The contamination was with the silty materials.

• Mr. Okumu also explained that the material if contaminated will not be dumped.

• Mr. Gwada explained that there are legislative frameworks to be followed especially

where Kenya is a signatory and has therefore to comply.

• Mr. Kombe expressed his concern about the consultant’s preparedness in the event

of pollution or other environmental disasters. He suggested that consultants come up

with a report to show their preparedness in the event of an emergency.

• Mr. Mwinyikai wanted to know the dredging areas, Mr. Adala explained.

• Mr. Mwinyikai also wanted to know what will happen to the fishermen after the

dredging as the fishermen will have been displaced and there will be a lot of

congestion.

• Eng. Nuru explained that aside from JBIC giving the fishermen the boats, it will also

give them training to ensure sustainability and maintenance.

• Mr. Mwinyikai further said that there are different types of fishermen who do different

types of fishing therefore cannot be accommodated in a single boat in a single area.

• Eng. Nuru explained that there will be monitoring to ensure the fishermen’s needs are

met.

• Mr. Adala explained that consultations are still ongoing and that the fishermen should

air their concerns which will be looked into and that the compensation decision was

not final and still up for further negotiations.

170

• Mrs. Martha Mukira suggested a fisheries stakeholder be part of the team in the

training of the deep sea venture. She also suggested a conflict management team

between KPA, fishermen and the fisheries.

• Eng. Nuru suggested that all fishermen have a valid license to enable KPA to know

who are to be rightfully compensated.

• Mr. Adala suggested there be further consultations concerning fishermen’s security

issues where Beach Management Unit, KWS and all stakeholders be involved where

all conflicts should be resolved .

• Mr Omari Bakari wanted clarification as to whether:

Fishermen will be able to fish in the dredged areas after the project

The sort of boat that will be given to the fishermen

• Mr. Adala explained that there is a provision for mobilisation and training and if not

there will be monetary compensation to be added. He also suggested that the

chairman of the BMU meet with Mrs Mueni who will then forward their concerns.

• Mr. Kombe also explained that in case the fishermen had any problems, the

consultants are available to forward their concerns.

• Grace Wendy explained that in regards to Mr. Gwada’s presentation, unlike what Mr.

Gwada explained that during the survey there were no turtles found around shelly

beach, there were actually turtles around shelly beach. She also suggested use of

standard vessels to avoid oil spillage.

• Mr Gwada explained that during the study, the turtles were not found as the study

was short but the dredging will not affect the nestling site for turtles but their migratory

route might be affected.

• Mrs. Mukira suggested that dredging not be done during the migration times of the

turtles and suggested all areas nurturing the animals like the turtles be protected.

• Ms. Joan wanted to know how the sea grass will be affected during dredging.

• Mr. Maina said that sedimentation during dredging should not be allowed to go

beyond the required levels.

• Mr. Otieno explained that the port area is not suitable for fishing because there was

some evidence of traces of heavy metals found in the port area which was being

consumed by the fish and therefore the human population which is highly detrimental

to the human health.

• He also said that KPA’s master plan has to have an environmental strategy. He also

said that the EMP is generic and therefore the need for an action plan. This needs to

be emphasised to the prospective contractor. He insisted the contractors and

171

consultants seek consultative process to the end which should be all inclusive and

transparent to avoid conflict as any conflict by parties could lead to the project being

stalled.

• Mr. Kombe closed with a word of prayer.

172

Coastal Oceans Research and Develpoment Indian Ocean (CORDIO), EAST AFRICA OFFICE

Date: 29.10.2008

Representatives: Dr Shakil Visram Associate Post Doctrate Fellow, Corals

Innocent Wanyonyi Associate, Regional Coordinator, SocMon WIO

Particular Area of Interest:

Coral Reef/ Species

Issues Discussed

1 Dr Visram requested that the consultants/client consider moving the off-shore

dumping ground further out. The feeling if cordio is that the dispersal plume, although simulating a scenario whereby the plume will outside the 50m contour (coral existence), the margin for error is slim.

2 Dr Visram inquired about the accuracy of the simulation model. If there was a an

in-accuracy in the the simulation model, the plume will definatley breach the 50m contour line.

3 Consider a further dumping ground. Perhaps 4 or 5km off-shore 4 Mr Wanyonyi inquired about the possible handling of contaminated material. The

consultants explained that there are mitigation measures in place that will ensure that un-acceptable material are identified early and disposed on land based, and contained receptors

Notes:

1 In stakeholder meet, expand on accuracy of Simulation Model - DR MAGORI 2 In stakeholder meet, explain contaminated material handling in detail - Eng

ADALA & DR MUNGA

173

Department of Coastal and Marine Fisheries, Ministry of Fisheries Devlopment, MOMBASA.

Date: 30.10.2008

Representatives: Mrs Martha Mukira Assistant Director, Fisheries.

Simon M. Komu District Ficheries Officer, Lamu

Elizabeth Mulwa Senior Fisheries Officer

Collins K. Ndoro Senior Fisheries Officer

Geoffrey Kamakya Senior Fisheries Officer

Stanley M. Nuguti District Ficheries Officer

Ephraim Wairangu Senior Fisheries Officer

Ndegwa Stephen Senior Fisheries Officer

Particular Area of Interest: Fishing and related

Issues Discussed

1 Mrs Mukira questioned the credibility of KPA to implement any mitigation

measures that were suggested in the study. She pointed out that since a recent oil spill, KPA have yet to fullfill their compensation pledged/ resposilibilities

2 The fisheries officers felt that this tudy should bring out the socio-economic

aspects very cleary.

3 Fisheries suggested that in future, KPA should look into adopting early mitigation measures against siltation e.g. farming in highlands and intergrated catchment management.

4 Mrs Mukira also suggested that KPA should also expand their Cooperate Social

Responsility to reach the communities from which the Fishers & PAP come from e.g. Drill BH, wells, markets

5 Fisheries requested that the EIA study include data on the effects of the 2005 Oil

Spill an it's effects on the fish stock at the port.

6 Fisheries queried if the local people were questioned during the study, especially the sea-turtle study

7 Mrs Mukira suggested that the study make recommendations to the formation of

a Turtle Nesting Ground Protection Act

8 Fisheries requested that The EIA study make recommendations to KPA to provide Fishing Gear and training as part of their compensation package.

9 Fisheries requested that the presentation be clearer on; data being current,

mitigation measures - containment, economic effects, effects on fish stocks,

10 Fisheries suggested that they work with KPA in the implemementation of mitigation measures

Notes:

1 KPA should prove commitment in stakeholder meet.

2 KPA to make stand on; oil spill, compensation (funds available),

174

National Environmental Management Authority, MOMBASA.

Date: 31.10.08

Representatives: Maurice Otieno Provincial Director of Environment

Particular Area of Interest: Regulatory

Issues Discussed

1 Mr Otieno feels that NEMA-HQ should have been thoroughly consulted on the

TOR of the study at the Genisis stage

2 Mr otieno suggested that we also consult with Kenya Maritime Authority. 3 Traffic control is an aspect that should be clear. 4 NEMA would like to know were previouse disposal sites are for dredging works.

Notes:

1 Contractor is required to submit a detialed port traffic control plan - Dredging Programme = Traffic Maintainance & Control (clause 8.1.4(3))

2 KMA to be invited to stakeholder consultation.

175

Kenya Wildlife Services, Mombasa

Date: 10.11.2008

Representatives: Mr Gitau Assistant Director, KWS

Alice Bett Research Scientist

Silas Murithi OC Intelligence

Grace Wendot Assistant Warden

Elijah Chege OC Investigation

Arthur Tuda Warden

Josphine Mituso Research Assistant

Immaculate Muthui Research Scientist

Rose Abae Research Assistant

Stephen Okoth OC Intelligence

Particular Area of Interest: Marine Protection

Issues Discussed

1 KWS pointed out that they will be in a better position to mak comments when

they read the final report.

2 Particular interest was drawn to th handling of contaminated material. 3 KWS noted that there might be a conflict between port boundary and Marine

Protected Area (MPA)

4 KWS would like some of the data to be more current e.g. details on shark species, details on sting ray species. This will be key in determining whether species are on the IUCN protection list

5 KWS suggested to ensure transect data are consistent which is good for

comparison

6 Study should consider Conservation of Migratoy Patterns - Sea Turtles 7 It was suggested that the possibility of invasion of some species as a result of

dredging works be addressed

8 KWS would like to see particular attention paid to port traffic control 9 KWS raised concern about the recovery of natural conditions at the dumping

grounds 10 KWS requested that an additional monitoring point be inculded within the MPA 11 KWS suggested that structures are put into place to ensure that the

implemementation and management of the compensation package for fishermen.

12 Effects of Noise, Vibration and Visual impacts on the environment should be highlighted.

Notes:

1 Provide information on containment of contaminated material

2 Add monitring point in MPA

176

Kenya Marine and Fisheries Research Institute, MOMBASA

Date: 12.11.2008

Representatives: Jared Bosire Assistant Director

EstherFondo Research Officer

Dr Michael Nguli Head of Research, Oceanography

Dr Charles Magori Research Officer

Dr Daniel Munga Centre Director

Julius Okondo Research Officer

Jaqueline Uku Research Officer

Veronica Wanjeri Laboratory Technician

Particular Area of Interest: Marine & Fisheries

Issues Discussed

1 KMFRI suggested that KPA should monitor siltation closely after the dredging

works. It was suggeste that they recommendations should be made for KPA to purchase an echo-sounder

2 KMFRI suggested as part of CSR, KPA should consider purchasing a small scale

dredger and assist the community by dredging siltation areas.

3 It was recommended that the EIA should also consider the use of siltation screens to minimise the dispersal plumes.

4 KMFRI requested an expansion on the contaminated material handling

technique. 5 KMFRI also requested that an extra monitoring position be included in the MPA. 6 KMFRI asked about the loss of habitat and wether the recovery potential and

period had been considered.

7 KMFRI requested that KPA be more involved in conservation of mangroves as (1) CSR and (2) siltation control

8 It was also queired whether the study has recommended "compenation

restoration" i.e. for every loss of habitat, similar habitat is created elsewhere.

Notes: 1 Look into implementation of siltation screens if monitoring levels show elevated

turbidity levels outside simulation prediction. 2 KMFRI to suggest CSR recommendations to KPA in the stakeholder forum

18.11.08 3 Add monitring point in MPA

4 Attain details of containment receptor for possible contaminated materials.

177

APPENDIX 3: Fishermen’s Memorandum of Understanding

178

179

180

181

APPENDIX 4: Inception Report

Kenya Ports Authority

Republic of Kenya

INCEPTION REPORT

Consultancy for Environmental Impact Assessment for

Dredging Works

at Port of Mombasa

August 2007

Prepared by HEZTECH ENGINEERING SERVICES for

Japan Port Consultants, Ltd.

in Association with

BAC Engineers & Architects

182

TABLE OF CONTENTS

Item Page

1.0 INTRODUCTION…………………………………………………………. 1

2.0 COMPOSITION OF TEAM……………………………………………… 2

3.0 SCOPE OF STUDY……………..………………………………………. 3

3.1 Scoping……………………………………………………………. 4

3.2 Baseline Studies…………………………………………………… 4

3.3 Impact Prediction…………………………………………………. 6

3.4 Mitigation…………………………………………………………. 7

3.5 Monitoring………………………………………………………… 7

4.0 EIA LEGISLATION IN KENYA…………………………………………. 8

5.0 TIME SCHEDULE OF EIA STUDY……………………………………… 8

6.0 ENVRONMENTAL ISSUES TO BE STUDIED……………….…………. 9

6.1 Methodology………………………………………………………. 12

183

1.0 INTRODUCTION

The port of Mombasa is considered as a major gateway for the importation and exportation of

goods to Kenya and neighboring countries. The port currently handles approximately 500,000

TEU’s per year and demand forecast show that there will be a steady increase in container

throughput at the port to approximately 1,600,000 TEU’s per year by the year 2030 (SAPROF,

2006). This factor, coupled with the worldwide trend towards larger (post-panamax) ships,

stresses the need for expansion of the Port.

For the port of Mombasa to meet these demands and become a destination for major trunking

routes there is a necessity to:

1. Construct a New Container terminal to accommodate larger capacity container ships

and increased container storage capacity.

2. Deepen and widen, i.e. dredge Turning Basin in front of the New Container Terminal

and Navigation Channels to the Port of Mombasa to allow for the bigger ships to dock

at the port.

Under these circumstances, in April 2007, the Kenya government through Kenya Ports

Authority commissioned Japan Port Consultants in association with BAC Engineering &

Architects (Consultant) to carry out the consultancy services, Dredging and Hydrographic

Works at the Port of Mombasa (Tender number KPA/041/2006CE), for implementation of the

above Turning Basin and Navigation Channel dredging project (Project).

As part of the consultancy services, the Consultant is required to carry out a successful

Environmental Impact Assessment (EIA) study and attain a license for the Project from

National Environment Management Authority (NEMA). The aim of the EIA study is to

greatly reduce or prevent environmental damage caused by the dredging and its associated

works of the Project. To achieve this, the Consultant has subcontracted the EIA study to a

team of environmental experts led by HEZTECH ENGINEERING SERVICES (Study Team).

Precise locations and dimensions of planned dredging works will be decided based on the

results of detailed design during the consultancy services, however, possible figures can be

presented as Figure 1.

184

Figure 1: Possible Locations and Dimensions of Dredging Works

As a result of tentative calculations, required dredging volumes at Turning Basin, Navigation

Channel at Inner Port and Port Entrance are estimated at 4.7, 0.2 and 2.4 million m3,

respectively.

Most of the dredged materials will be disposed at a planned offshore dumping site located

about 6km offshore from the port entrance (see Figure 3). Some sandy or hard materials will

be utilized as filling materials for reclamation of the New Container Terminal.

It is noted that apart from the EIA for the Project, an EIA for the New Container Terminal

Construction Project was approved by NEMA on 31st May 2007.

This report has been prepared by the Consultant for KPA’s approval of the proposed scope

and time schedule of the EIA study for the Project.

Navigation Channel at Port Entrance Width: 300m, Depth: -17.5m

Navigation Channel at Inner Port Width: 300m, Depth: -15.0m

Turning Basin Area: 50ha, Depth: -15.0m

Anchorage Basin

Small Craft Basin

New Container

Terminal

185

2.0 COMPOSITION OF STUDY TEAM

The Study Team has been formed comprising of eight (8) specialists listed in Table 1, each

with responsibility for specific part of the EIA study.

The EIA study shall be supervised by M Okumu, Environmental Specialist of the Consultant.

Table 1 Composition of Study Team

Name Specialty

H Adalla (Heztech Eng. Services) Environmental Engineer / Team Leader

D Munga Pollution Expert

P Gwada Marine Ecologist

C Magori Oceanographer

E Mweni Fisheries Expert

J Ochiewo Socio – Economist

C Odhiambo Health & Safety Coordinator

F Owiti Environmental Scientist

186

3.0 SCOPE OF EIA STUDY

Figure 2 shows the stepwise nature of the EIA study and the requirement for continuous

reappraisal and adjustment (as indicated by the feedback loops)

Scope of the EIA study will involve the following components:

3.1 Scoping

Scoping is an essential first step in the assessment. The main aims are:

• To identify at an early stage (when the project design is relatively amenable to

modification) what the key receptors, impacts and project alternatives to consider, what

methodologies to use, and who to consult

• To ensure that resources and time are focused in important impacts and receptors;

SCOPING AND PREPARATION OF TOR

BASELINE STUDIES

DESCRIPTION & EVALUATION OF BASELINE CONDITIONS

IMPACT PREDICTION

FORMULATION OF ENVIRONMENTAL MANAGEMENT

PLAN

(MITIGATION & MONITORING)

MONITORING (during Construction and Operation)

Primary pathway Feedback loops

Figure 2: Procedures on Environmental Components of EIA Study

PRESENTATIONS OF FINDINGS (REPORT)

EIA APPROVAL BY

NEMA

Scope of EIA Study

187

• To establish early communication between the client (KPA), consultants, NEMA and

other major stakeholders who can provide advice and information.

• To alert KPA of any possible constraints that may pose problems if not discovered

until later in the EIA process.

The scoping exercise will provide an implementation plan for subsequent steps by making

a preliminary assessment of:

• potential impacts of dredging on component receptors, estimated from the project

description;

• the impact area/zone within which impacts are likely to be effective, estimated from

the impact types and the nature of the surrounding area;

• possible mitigation measures;

• the methods and levels study needed to obtain reliable baseline information to

evaluate baseline conditions

3.2 Baseline Studies

This component will form the backbone of component assessments. It is only when they

provide sound information on the environmental systems around the port that valid impact

predictions can be made and effective mitigation and monitoring programs formulated.

Baseline studies will provide:

• a clear presentation of methods and results;

• indications of limitations and uncertainties, e.g. in relation to data accuracy;

• an assessment of the value of key receptors and their sensitivity to impacts;

• a very comprehensive sediment and water quality analysis for contamination levels

(see Figure 3 and Table 2), carrying out concentration analysis of key parameters

selected by the Consultant at a laboratory accredited by NEMA.

• Existence of coral reef in areas close to dumping site (see Figure 3).

• Environmental effects of different dredging methods to be used in this project.

Alternatives.

188

Figure 3 Locations of Baseline Studies

Table 2 Description of Sediment and Water Quality Analysis

Item Parameter Sampling

Sediment Quality Organics, Heavy metals (Cd, Hg,

Pb, As, Cr), Grain size

Samples will be taken by divers from

50cm below waterbed surface.

Water Quality

Temp, pH, Salinity, Organics,

Nutrients, Heavy metals (Cd, Hg,

Pb, As, Cr), Coliforms, Turbidity

(SS)

Samples will be taken from 3 layers (1m

below surface, middle and 1m above

waterbed surface), but from 2 layers (1m

below surface and 1m above water be

surface) in case water depth is less 10m.

Sampling will be done during ebb tide.

Mombasa Marine National Reserve

New Container Terminal

New Container Terminal

Dumping SiteDumping SiteDumping SiteDumping Site Water Quality : 12 points

Sediment and Water Quality : 8

points

Sediment and Water Quality : 15

points

Turning Turning Turning Turning

Area of Coral

Survey

189

3.3 Impact Prediction

Impact prediction of dredging will include:

• Direct/ primary impacts – that are direct result of dredging

• Indirect/ secondary impacts – that may be “knock-on” effects of (and in the same

location as) direct impacts, but as often produced in other locations and/or as a result

of a complex pathway.

• Cumulative impacts – that accrue over time and space from a number of

developments or activities.

The Consultant and Study Team, in order to predict impacts will;

• have a good understanding of dredging, channel design, construction activities and

timing;

• have knowledge of the outcomes of similar projects and EIAs, including the

effectiveness of mitigation measures;

• have knowledge of past, existing and approved nearby projects that may have

cumulative impacts with the proposed dredging works.

• Attain adequate information on relevant receptors, and knowledge of how these may

respond to environmental changes.

There are several techniques that can aid in impacts prediction and assessment of

environmental components. Checklists are useful in identifying key impacts and ensuring

that they are not overlooked, especially in scoping. They will include information such as

data requirements, study options, questionnaires and statutory thresholds. Matrices will

be used for impact identification and also to show cause link effects between impact

sources and impacts. They can also indicate features of impacts such as their predicted

magnitudes and whether they are likely to be localized or extensive, short or long term etc.

Flowcharts and networks will be used to identify cause-effect

relationships/links/pathways: between impact sources; between sources and impacts; and

between primary and secondary impacts. Computer Simulation will be applied to

calculate deterministic or probabilistic quantitative values from numerical input data.

Maps will also be used as an indicative tool.

190

3.4 Mitigation

Mitigation measures will aim to avoid, minimize, remedy or compensate for the predicted

adverse impacts of the project. Much of the environmental damage from dredging

activities occurs during the actual works stage when material is harvested/ dredged and

subsequently dumped. There would be need for an adequate dredging phase

management plan to deal with any changes and to closely monitor the work which will

be carried out by a contractor.

The mitigation measures to be proposed in the EIA study shall be realistic and

sustainable.

3.5 Monitoring

Monitoring can be defined as the continuous assessment of environmental or socio-

economic variables by the systematic collection of data in space and time. It can be

continuous but in this case will involve periodic repeat data collection. Monitoring in this

project will include baseline monitoring, impacts and mitigation monitoring during

dredging and compliance monitoring during maintenance dredging activities.

Monitoring will be used to verify whether the conditions of the EIA license from NEMA

are met – compliance monitoring – and that the assumptions made during the EIA review

and site selection process were correct and sufficient to protect the environmental and

human health – field monitoring.

The monitoring plan to be proposed in the EIA study shall include parameters, locations,

frequencies, duration, target values, required cost, human resource and institutional

arrangement of the monitoring activities.

4.0 EIA LEGISLATION IN KENYA

The Environmental Management and Coordination Act (EMCA), 1999, largely governs

environmental legislations in Kenya. The National Environmental Action Plan initialized this

Act.

Under Part III of the EMCA, 1999, the country has a council known as the National

Environmental Council, which is chaired by the Minister for Environment and Natural

Resources. The council is responsible for formulation and prioritization of the policies within

the Act. The council has appointed an authority whose objective and purpose is to exercise

191

general supervision and coordination over all matters relating to the environment and to be the

principle instrument of government in implementation of policies at all levels. This authority

is known as the National Environment Management Authority (NEMA), which is based in

Nairobi.

The Council appoints a Provincial Environment Committee. The Provincial Environment

Committee is responsible for the matters specified in the first schedule of the provincial level

and whose area for jurisdiction falls wholly or partly within the province. The Committee is

responsible for the proper management of the environment within the province.

The Council appoints a District Environment Committee. The District Environment

Committee is responsible for the matters specified in the first schedule of the provincial level

and whose area for jurisdiction falls wholly or partly within the district. The Committee is

responsible for the proper management of the environment within the district.

5.0 TIME SCHEDULE OF EIA STUDY

The EIA study will be conducted following the time schedule shown in Table 3.

Table 3 Time Schedule of EIA Study

Component 2007

July Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr.

Preparation

Baseline Survey

Impact Prediction

EMP Formulation

Assistance for EIA

Approval

Reporting

Inception Interim Draft Final EIA

Final EIA Submission for Approval

(Computer Simulation)

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6.0 ENVIRONMENTAL ISSUES TO BE STUDIED

Dredging, like most maritime development activities, throughout history has been known to

have serious implications on many aspects of the environment and some of them could be

permanent if inadequate mitigation techniques are not implemented. The port and its

surrounding can be very rich and sensitive in natural and renewable resources that need to be

studied when implementing a project.

The consultants will compare different dredging and disposal options to determine whether

the proposed dredging methodology is the most environmentally suitable. The consultants

will take into account the following aspects:

1. Types of Dredgers and their associated impacts.

2. Dumping alternatives; open water, land and beneficial (reclamation) options,

considering implementation schedule of the New Container Terminal Construction

Project.

3. Necessity of channel dimensions (depths & widths)

4. Dredging time schedules and suitability with regard to seasonal environmental

conditions and water dynamics.

Proper selection of a dump site at sea for the reception of dredging waste will be assessed.

The information the consultants will collate will include:

1. Physical, chemical and biological characteristics of the water column and the sea bed.

2. Location of amenities, values and other uses of the sea in the area under consideration.

Recreational, scientific interest, historical, fishing/economical, shipping, military

exclusion.

3. Assessment of the constituent fluxes associated with dumping in relation to existing

fluxes of substances in the marine environment.

4. Economic and operational feasibility.

A common problem in dredging in tropical countries such as Kenya is the dispersal and

resettlement of suspended particles on sensitive aquatic ecosystems e.g. coral reefs. This

issue is more prominent when carrying out capital dredging than in comparison with

maintenance dredging mainly because of the dredging volumes. Similarly, deepening can

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result in increased shoreline wave action with consequent accelerated erosion and other

problems. The preferential use of a trailer suction dredger will allow for minimal allowance of

sea bed material during the works. Suction dredgers operate by sucking through a long tube,

like some vacuum cleaners. The tube can have a cutter to disturb stubborn material though on

this project the material is expected to be soft hence no need for a cutting tool. The study team

will apply simulation numerical model of diffusion of SS and sedimentation of dumped soils.

See Appendix 1 for methodology of the dispersal and settlement simulation model.

In order to ascertain appropriate dumping locations, it is important to carry out dredged

material characterization. Previous studies in the area have shown that there is a possibility

for heavy metal contamination in the upper layer of the sea bed around the port. If this is

confirmed, the dredging material will be classified as hazardous material and would require

specialized dumping techniques which will be explored in this study. If the material is

confirmed clean it can be dumped or beneficially used for engineering purposes (such as

reclamation), or for environmental enhancement (beach replenishment). Figure 4 shows the

framework to be used for assessment of dredged material. Characterization should be done for

chemical, physical and biological properties.

NB: All analytical work will be carried out in a NEMA accredited laboratory and all results

will be accompanied by Quality Control Data.

In the case where contamination is identified, the consultants will provide a solution taking

into account the criteria and standards to be used, the economic considerations i.e. cost

effectiveness and the most suitable technological clean up technique to be used.

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NEED FOR DREDGING

Dredged material

Characterization

Is material

acceptable?

Beneficial Use Possible? Beneficia

l Use

YES

No

Identify and Characterize

Disposal Site

Determine Potential Impacts

and Prepare Impact Prediction

Can Material

Be Made

Acceptable

YES

No

No

Other

PERMIT?

YES

YES

DREDGE/DUMP &

MONITOR

Figure 4: Dredged Material Assessment Framework.

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6.1 METHOLOGY PROPOSED DREDGING OF THE ACCESS CHANNEL AT KPA, MOMBASA

Item Details Deliverable

Project

Description

The consultants would identify the development

project to be assessed and explain the

executing arrangements for the environmental

assessment. This section of the report will

detail the rationale for the development and

its objectives. Also to be covered is the

context of the proposed project in relation to

future plans for development of Mombasa Port.

A detailed project outline will be given

to familiarize stakeholders on the project

objectives and scope. This is to include: quality and volume of sediments to be

excavated in each area to be dredged; type

of dredging equipment to be used and the

manner of deployment including handling,

transportation, and disposal of dredged

material, sediment containment settling

and turbidity control measures;

alternative dredging methods considered;

project schedule; and project life span.

Legal &

Regulatory

Reference.

Conventions

and Codes.

The consultants will identify relevant and

appropriate legal and regulatory references to

be used in the study and in decision/ action

making. Standards.

E.g. London Convention 1972, World Bank,

EMCA 1999, International Association of

Dredging Companies (IADC), Central

Dredging Association (CEDA), UNEP.

Baseline

environmental

data

Consultants will document the current state of

the study area in relation to current and

future state.

Brief description of physical environment,

biological environment, socio-economic

state and hazard vulnerability.

Materials

Classification

Study needs to determine the characteristics

of the material in the areas to be dredged.

This will mitigate impacts caused.

Materials testing to determine chemical,

biological and physical characteristics.

This information is critical to

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determining disposal or treatment of

dredged techniques. Refer to chapter 4

Dispersal of

Suspended

Sediments

Sediments become re-suspended during initial

excavation and during deposition at designated

dumping sites. The consultants will determine

dispersal and settlement of re-suspended

sediments:

Dependant on dredging methods. Simulation

model of diffusion of SS and sedimentation

of dumped soils to be used. See Appendix 1

Effects on

tidal patterns

Influence on tidal and river flows. Altered salt wedge intrusion. Accelerated natural sediment deposition. Attraction of desirable or undesirable fisheries. Altered bottom biota.

Bathymetric survey data to be analysed

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Shoreline

configuration

Change in current patterns can lead to

subsequent shore and coastal erosion.

Identify possible affected areas.

Effects on

ecological

component

Dredging and dumping activities can lead to

Loss of bottom habitat (sea turtles), shell fisheries, fishery food resources: Exposed subsurface materials unconductive to recolonization. Lost attachment potential for aquatic biota. Current pattern changes.

Sea bed investigation for faunal and

floral species and cross reference with

protected species list etc. Record of

designated sites e.g. Marine Park

Noise from

dredging

activities

Ascertain the background noise levels

generated currently and compare with predicted

noise levels generated by the proposed

dredging equipment.

Noise survey to be carried out by the

consultants to get relevant noise levels

at source and at impact zones

Handling of

Contaminated

Material

Determine toxicity levels of the dredged

material possible remediation and containment

techniques. Important to determine the bio-

availability of heavy metals.

Sediment and water sampling from numerous

points in areas to be dredge with

subsequent testing in accredited

laboratory. If contaminated, suggest

possible remediation and containment

techniques of material. Action list, see

chapter 4.

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Air Quality Assess whether the dredging activity will

cause air pollution during construction and

whether the increased traffic of vessels will

lead to fugitive gas and reduced air quality.

Desk study exhaust data from different

dredgers and compare with standards.

Identify any possible receptor areas.

Monitoring plan to ensure machine

emissions.

Socio Economic

Impacts

Dredging and dumping of dredged material can

lead to loss of fishing grounds.

Study nearby fishing grounds and whether

fishing activities will be affected.

Negotiate adequate compensation for loss

in earnings

Groundwater

Flows

Dredging can lead to alteration on nearby

subsurface groundwater flows near the land-sea

interface. Possible intrusion of saltwater in

freshwater streams

Identify any nearby land-sea interfaces

and assess risk of intrusion.

Alteration in

Port Traffic

Patterns.

Impact on navigation, traffic control, vessel

handling and servicing needs to studied as the

results of channel dredging, anchorage and

turning basins.

Assure that navigation aids such as Buoys

are precisely located and visible

(International Association of Lighthouse

Authorities Maritime Buoyage Systems).

Introduction

of Ship

Discharges

Determine the types of different discharges

from increased vessels in the areas dredged

and the impacts on the environment. Address

Spill detection and clean up procedures in

newly dredged areas.

Address pollution prevention techniques

from ships in relation to MARPOL 73/78 and

International Convention for the Prevention of Pollution from Ships, 1973. Provide contingency plans for spills

Land related

impacts

In the event that some of the dredged material

is classified as contaminated, land containment facilities could be used

Address any land related impacts from the

possible land containment facilities

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Impacts on

vehicular

traffic

Assess whether port expansion will increase

vehicular traffic in the area.

Explain the construction of new access

road as part of the container terminal

expansion project to deal with increased

traffic.

Disposal

Options

To choose the most environmentally suitable

disposal options for the different

classifications of dredged material

To provide a multi option disposal

programme adequate to the type of material

being dumped.

i. open water

ii. shoreline

iii. upland

iv. contained/ non contained

200