COASTAL PROTECTION, LANDSCAPING AND INFRASTRUCTURAL WORKS IN MAURITIUS BAIE DU TOMBEAU SITE CONTENTS

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1 COASTAL PROTECTION, LANDSCAPING AND INFRASTRUCTURAL WORKS IN MAURITIUS BAIE DU TOMBEAU SITE CONTENTS Chapter Description Page EXECUTIVE SUMMARY 1 INTRODUCTION General Need for EIA The Project General Coastal Erosion Project Background Previous Studies Actions taken by MSSESD The Proponent and Project Team The Proponent The Project Team Project Implementation Timeframe Method of Assessment General Phases of Assessment Scoping Structure of Report LEGAL FRAMEWORK Introduction Legal Framework Environment Protection Act, Regulations Policies, Planning Schemes and Guidelines General National Environment Policy National Development Strategy Environmentally Sensitive Areas (ESA) National Forest Policy International Treaties 2-5

2 2.4.1 The Convention on Biological Diversity International Convention and Protocol Signed/Ratified by Mauritius BASELINE ENVIRONMENT Site Description and Context Jurisdiction over Waterfront Waterfront Features Land and Water Use Landside Access to Waterfront Pedestrian Access along Waterfront Historical Features 3-6 Rivulet Terre Rouge Estuary Bird Sanctuary Site Topography Elevation Datum Horizontal Datum Bathymetry Utilities and General Infrastructure Power, Potable Water and Sewers Stormwater Drainage Geology and Geomorphology Geology Site Observations Sediment Sampling and Test Results Sediment Transport and Morphology Coastal Hydrodynamics Baseline Modelling Model Calibration Climate Change Effects Water Level Tide Levels Climate Change and Sea Level Rise Climate Water Levels Cyclones Wind Wind Regime Waves and Surges Hydrodynamic Modelling for Baie du Tombeau Site Water Quality Biodiversity General Terrestrial Environment Marine Environment Landscape and Aesthetics 3-26

3 3.13 Air Quality Traffic / Access to Site Noise Land Ownership Socio-economic Activities Tourist Industry Fishing Activities Other Activities Consultation with Stakeholders Ministries and Authorities Public Consultation PROJECT ALTERNATIVES AND JUSTIFICATION General Functional Requirements (Client s Requirements and ToR) MSSESD Requirements Stakeholder Requirements Protection against Erosion Design Parameters dictated by Met-ocean Conditions General Extreme Still Water Levels Extreme Wave Heights Wave Directions Overtopping Discharge Drainage Impact of Planned Development of Mer Rouge Container Terminal Maximum Crest Level vis-a-vis Visual Impact Other Requirements Construction Aspects Development Options Design Considerations Review of Previous Recommendations Project Alternatives Alternative 1 Do-nothing Scenario Alternative 2 - Retreat Alternative 3 - Soft and Semi soft Solutions Alternative 4 - Vertical Seawall Alternative 5 - Rock Revetment Preferred Solution and Approved Scheme Adaptability to Climate Change PROJECT DESCRIPTION 5-1

4 5.1 General Proposed Works and Site Layout Extent of site Site Layout Project Description Drainage Measures Boat Ramp Reference Standards and Publications General CUR CIRIA Publications British Standards Design Method Toe Armour Materials Generally Fill Construction Methodology IMPACT ASSESSMENT AND MITIGATION MEASURES Methodology Construction Phase General Water Quality Biodiversity Air Quality Traffic Socio-economic Noise Health and Safety Operation/Utilisation Phase General Geomorphology and Hydrodynamic Impacts Landscape and Aesthetics Socio-economic Impact Significance of Impacts during Operation Phase Maintenance as a Mitigation Measure ENVIRONMENTAL MONITORING PLAN Monitoring during Construction Phase Air Quality Noise Water Quality Solid Waste Traffic Infrastructure 7-3

5 7.1.7 Health and Safety Monitoring during Operation Phase RECOMMENDATION AND CONCLUSION 8-1

6 List of Appendices: Appendix A Appendix B Appendix C : Laboratory Test Results for Water and Sediment Samples : Marine Flora and Fauna Survey Report : Drawings List of Drawings: Context Map Sampling Location Location Plan Topographic Map Proposed Layout Plan Typical Cross Section M190/BDT/EV/01 M190/BDT/EV/02 M190/BDT/DD/01 M190/BDT/DD/02 M190/BDT/DD/03 M190/BDT/DD/04 List of Figures Figure 3-1 Site location within the bay Figure 3-2 Site Limits Figure 3-3 Existing site waterfront Figure 3-4 Eroded Coastline and Boundary Walls Figure 3-5 Existing boundary wall types Figure 3-6 Erosion and accretion along site waterfront Figure 3-7 Land and water use Figure 3-8 Landside access to waterfront Figure 3-9 Pedestrian access along waterfront Figure 3-10 Site Geology Figure 3-11 Scattered rocks and construction debris Figure 3-12 Aerial Photograph of Baie du Tombeau, Figure 3-13 Direction of mean wave energy flux (top) and wave roses (bottom) Figure 3-14 Raw water level data measures at Port Louis (Caldwell, et al, 2015), shown relative to Mean Sea Level (MSL) Figure 3-15 Water level data measured at Port Louis (Caldwell, et al., 2015). The data shown was detrended, with a mean level equal to the measured mean level at 1995, calculated as the average over Figure 3-16 Measured Water Level at Port Louis with SLR Trend Lines Figure 3-17 Extract from Chapter 13: Sea level change in the Fifth Assessment Report (IPCC,2013) Figure 3-19 MFR best track data for the years 1980 to Also indicated are the three locations used in the calculation of extreme wind speed Figure 3-21 trends in average wind speed based upon climate change (Tokinaga, 2011) 3-20 Figure 3-22 Trend in wind speeds per decade for for different climate models (IPCC, 2013) Figure 3-23 Whimbrel Figure 3-25 Aerial view of site where darker ones in the sea shows coral patches Figure 3-26 Coastal road and access to site Figure 4-1 Flooded container terminal during Cyclone Dina, January Figure 4-2 Wall top and predicted still water levels at Baie du Tombeau