chapt 6 - mauritius wind speed

Extension and Strengthening of the MCT Quay

at Port Louis Harbour EIA Report

6-1

6 BASELINE ENVIRONMENT

6.1 General Climatic Conditions

Mauritius has a moderate tropical climate characterized by a hot, humid summer between

November and April (average mid-day temperature 25C on the Central Plateau and 30C on

the coast), followed by cooler and drier winter period (19C and 24C respectively). Seasonal

rainfall patterns are distinct, with about 50% of the annual rainfall (average 1,200 mm)

occurring between January and March, and often little or no rainfall during November to

December.

6.1.1 Wind Regime

Mauritius is situated in the equator-ward belt of the southern sub-tropical anticyclone system.

Atmospheric pressures at the surface increase southward in this belt, creating a gradient,

which maintains a general easterly flow.

The prevailing wind pattern in Mauritius is the South Eastern trade winds, except for short

periods in the summer months when tropical storms approach the island. The trade winds

are stronger and more persistent in winter when strong anticyclones pass to the South and

close to the island. In the area of Port Louis, the wind pattern is modified by the arc of

mountains lying on the eastern side of Port Louis as shown in Figure 12 below (source:

Mauritius Meteorological Station).



6-2

Figure 12: Wind Rose for Fort William (2006-2007)

The strongest gusts recorded instrumentally in Mauritius have been of 280 kilometres per

hour (Feb 1975) and records of gusts of over 250 km per hour have been made in earlier

cyclones.

The values for 3 second gusts proposed by the Mauritius Meteorological Service in a paper

dated May 1994 is as follows:

Return Period of 50 years : 240 km/hr (67 m/s) Return Period of 100 years : 280 km/hr (76 m/s)

The Mauritius Ports Authority and other authorities have recommended the use of a basic

wind speed of 300 km/hr (83 m/s) for recent projects.



6-3

6.1.2 Temperature

Mean maximum and mean minimum monthly temperatures for the western region, i.e.

Medine meteorological station are reported in Table 5 below (CSO/MMS, 1991-2000).

Mean minimum temperatures are recorded during the winter season in July and August.

Mean maximum temperatures are recorded during the summer season from December to

March.

The design temperatures extremes are 38C max and 10C minimum.

Seasonal temperature variations should cause no effect to and from the proposed project

due to the type of activity involved.

MONTH MEAN MAX TEMP (C)

MEAN MIN TEMP (C)

January 30.4 22.5

February 30.3 22.7

March 30.2 22.3

April 29.5 21.3

May 28.1 19.5

June 26.4 17.7

July 25.8 17.0

August 25.9 17.0

September 26.7 17.5

October 27.8 18.6

November 29.1 20.0

December 30.0 21.9

Table 5: Temperatures records Medine

6.1.3 Rainfall

6.1.4 Rainfall Regime

The comparative low annual rainfall for Port Louis and the western coast in general arises

from the prevailing pattern of the south eastern trade winds.



6-4

These winds rise over the island and cause precipitation mainly on the higher Central

Plateau and its eastern slopes. When the winds reach the lower regions, and the north

western coast, they have already dropped most of their moisture.

Average monthly rainfall for the western region, i.e. Medine meteorological station is reported

in Table 6 below (CSO/MMS, 1991-2000).

The months from July to November are the driest months. December to March figures are

above 100mm monthly rainfall.

Seasonal rain variations should cause no effect to and from the proposed project due to the

type of activity and to the small extent of site involved.

MONTH AVERAGE RAINFALL (MM)

NO. DAY WITH RAINFALL >5MM

January 153.2 9

February 181.8 10

March 86.2 8

April 87.6 8

May 42.7 5

June 29.0 4

July 15.4 3

August 14.8 3

September 12.5 2

October 16.5 2

November 25.7 3

December 115.6 7

TOTAL 781

Table 6: Mean monthly rainfall Medine



6-5

6.1.5 Cyclones and Natural Catastrophes

6.1.5.1 Cyclones

Mauritius is subjected to possible seasonal tropical cyclones in the months of December to

March/April. Cyclones are characterised by low pressure conditions and high wind systems.

From records available at the Mauritius Meteorological Services, over the period 1960-70,

39% of cyclones were classified as Weak, 42% as Moderate and 19% as Strong with

gust speeds over 80km/h.

Mauritius has been visited by major cyclones on an average frequency of one in about 15

years. However, it should not be thought that there is a regular succession of cyclones

occurring once every fifteen years. There is considerable irregularity in their occurrence.

Since cyclone Dina in 2001, Mauritius has not been subject to strong cyclones.

6.1.5.2 Natural Catastrophes

Seismic Activity in the Project Area Mauritius is part of the Mascarene Islands which were formed in a series of volcanic

eruptions 8 million years ago, as the African tectonic place drifted over the Reunion hotspot.

Mauritius is no longer volcanically active, however the neighbouring island of Reunion still

has active volcanoes. The most recent activity was an earthquake in 2010 measuring 6.2 on

the Richter scale with the epicentre 902km east-northeast of Port Louis. The Uniform

Building Code (UBC) defines Mauritius as Zone 0, therefore it is not considered critical to the

design.

Risks of Tsunami Mauritius was not affected by the Tsunami in December 2004, however the island may be

subject to a tsunami and an observatory for the same has been established in Mauritius.

Elevations in sea levels which have been recorded from North to East of the island have not

exceeded 2.0m following the 2004 tsunami.



6-6

Sea level rise Sea level rise is predicted by the Proudman Institute at 5mm per year for the next 50 years to

100 years.

Elevations in sea levels caused by cyclones do not exceeded 2.0m as explained below,

however high wind systems over the sea can contribute to formation of occasional waves

exceeding this value.

In the event of a cyclone occurring in a period of High Springs tides, the total rise in sea level

would be, at least:

Sea level rise due to Inverse Barometric Effect: 0.80m re MSL. Sea Level rise under high Springs: 0.30m re MSL. Total possible sea level rise1.10m re MSL

To the Inverse Barometric Effect concurrent with high Springs, a piling up of water at the

shore line due to wind and wave effects and the prevailing tidal influence, must also be

expected. Thus, the swash line will reach rather high up the beach: ~ 1.97m above MSL

which has been observed in some areas along the coast.

6.2 Site and Project Area

6.2.1 Description of Site

The site of the Mauritius Container Terminal (MCT) is located in Mer Rouge at Port Louis.

The Port Louis Harbour is the sole maritime gateway of Mauritius which provides terminal

facilities and services to both international and inter-island shipping. It is located in a natural

protected bay on the North West coast of the island and covers an area of about 300

hectares as shown on Figure 2: Project Location.

The MCT comprises a modern Container terminal of approximately 27 hectares with a 560

metre long quay equipped with 5 post panamax Rail Mounted Quay Cranes (RMQCs)

including a Container Park spanning over 13 ha. The MCT also involved the creation of an

independent access channel 400 metres wide with a turning circle of 425 metres diameter at

a dredged depth of 14 metres.



6-7

Other facilities include a Customs Verification Centre, a Workshop Complex, an

Administration Building and unpaved areas reserved for future yard expansion.

Mer Rouge Port area also accommodates the Mauritius Freeport Development Co Ltd, the

Petroleum jetty, the LPG storage facilities and coal storage area.

The Maintenance dredging area is located in the channel facing Quay 1. This area also

comprises the shipyard/dry docks, the tank farm/open bulk storage, Fort George and the

chemical fertilizer compound. The Bulk Sugar Terminal is located on the western side of the

channel.

Land in the port area is under the control of the Mauritius Ports Authority and access to the

port area is restricted to authorised personnel and visitors with valid passes.

6.2.2 Project Area

The Project area comprises land within 1,000 m of the site boundaries, which is the extent of

the area commonly considered in Environmental Impact Assessment studies in Mauritius.

The Area of Environmental Influence for this project is considered to be much smaller than

the project area and can be reduced to 500 m from the site boundary.

The Project Area and Area of Environmental Influence are shown in Figure 13 below and

referenced as Drawing No. 10/149/L1 in the Drawing Section of the EIA report.



6-8

Figure 13: Project Area and Area of Environmental Influence

The Project area as indicated on Figure 13 includes the following main man-made features:

Residential Areas o To the north east: Tombeau Bay o To the south east: Roche Bois o To the south west: Les Salines

Port Activities o From east to south all other sectors of the Port

Project Area (1000m

Area of Environmental

Influence (500m radius)



6-9

The Project area as indicated on the Location Plan includes the following main natural water

features:

Port Louis Harbour and further west the open sea Rivulet Terre Rouge estuary: 515m from the existing quay Latanier River and La Paix are located outside the project area at some 1.4kms

The Fort William area is located on the southern side of the main navigation channel into Port

Louis harbour.

The main existing installations in Fort William are:

the Bulk Sugar Terminal the National Coast Guards headquarters the new fish auction market two storage tanks for heavy fuel oil

Photographs of site and study area are shown in Appendix A.

6.3 Site Topography & Bathymetry

6.3.1 Site Topography

Land in and around the project area of Mer Rouge has been modified extensively over the

years from the first reclamations to the more recent work carried out to form the Mauritius

Container Terminal.

A topographic survey was carried out in November 2011 by Servansingh Jadav and Partners

Consulting Engineers Ltd and is shown in Figure 14 below and referenced as Drawing No.

DD-YD-304 in the Drawing Section of the EIA report.

The landform of the project area consists of flat land bordering the harbour and lying between

1.4 and 2.5 m ACD in altitude. The existing MCT quay is at 2.6m ACD.

Land in and around the project area of Fort William has also been modified; it comprises

about 32.5 hectares of land, including a land area of about 15 hectares which has been



6-10

reclaimed over the last decade. Substantial land filling has taken place with dredged material

from the deepening of the navigational channel to the Mauritius Container Terminal. Some

500,000 cum of dredged material is still stockpiled there pending its use for proposed further

reclamation works in that area.

Offshore of the Fort William area there are extensive shallow areas which will allow

reclamation of additional prime port land. The water averages about 1.5 meters depth for a

distance of approximately 650 to 800 meters from the shore before dropping off to a 5 to 10

meter depth.

Figure 14: Topographic Map



6-11

6.3.2 Site Bathymetry

The latest bathymetric survey of Mauritius Container Terminal commissioned by the

Mauritius Ports Authority was carried out in November 2006 by the Netherlands-based

company Royal Boskalis Westminster N.V.

The bathymetric plan is shown on Figures 15 and 16 below and referenced Drawings No.

BKI-480-10000-06-11-144 and BKI-480-10000-06-11-145 in the Drawing Section of the EIA

report.

The bathymetric survey shows that the sea bed is currently dredged to a level of -14.5m CD

with a large, naturally occurring pocket in excess of -16.5m CD which shall remain as is.

Figure 15: Bathymetric Map Channel (Sheet 1 of 2)



6-12

Figure 16: Bathymetric Map - MCT (sheet 2 of 2)

6.4 Site Geomorphology

6.4.1 Site Geology and Pedology

The geology of Mauritius is dominated mostly by deposits of basaltic lavas following volcanic

activities which occurred during two distinct periods. The general series of basaltic rocks are

as described in Table 7 below.

LAVA SERIES AGE (MILLION YEARS BC.)

Younger Volcanic Series

Late Lavas

Intermediate Lavas

Early Lavas

0.025 to 0.2

0.5 to 0.7

1.7 to 3.5

Older Volcanic Series 6.8 to 7.8

Table 7: Volcanic Series

The extract of the Land Resource and Suitability Map, FAO/MSIRI relevant to the Project Area is reproduced in Figure 17 below.



6-13

Figure 17: Geological Map - Land Resource and Suitability Map

The comparison between the above geological map and the aerial picture shown on Figure 2

shows clearly that:

The area of the Mauritius Container Terminal has been reclaimed over Mer Rouge up to Fort George and Tonneliers Island which are classified as a Sand Beaches and

Dunes land complex (land unit mapping symbol 13.1),

The area of Fort William has undergone extensive reclamation also

Major reclamation works were carried out in 1990, whereby some 110 ha of land were

reclaimed in the Mer Rouge area.

Based on the geotechnical report entitled Geotechnical Investigations in Mer Rouge Area for

the Construction of an Oil Jetty and Extension of Existing Container Terminal at Mauritius by



6-14

Aqualia Ltd, the geological units encountered in the available boreholes and cone penetration

test can be generalized as follows:

Fill material made up of dredged coral sand and fragments; Marine deposits consisting of very loose to loose sand, soft clayey silt, coral

fragments and shells (Delatic / Esturine);

Medium dense sand and/ or firm to stiff silt/clay; Cemented coral sand and shells, calcarenite and calcareous silt/clay (Buried Reef); or Highly weathered to fresh vesicular and compact basalt.

The stratigraphy of the project can generally be described as a Pleistocine sequence of

basalt overlain by a variable thickness of weathered basalt, sand coral, fossileferous

limestone (cemented coral & shell), calcarenite and calcareous silts or clays.

The current nominal finished landside level is around +2m to +3m ACD based on the land

boreholes.

6.4.2 Site Geotechnical Conditions

The land area has been reclaimed by the placement of 5 to 6m of dredged sand and coral

debris (fill) from the nearby channel area.

The seabed level in front of the berth is generally at an average of -11m to -15m CD.

Underneath this fill layer is a bed (approximately 20-50m thick) of very loose to loose sand,

soft marine soils (silt, clay & sand) and coral layers.

The bores in the report by Aqualia Ltd also identified a bedrock unit which is comprised of

vesicular closely jointed basalt and compacted basalt underlies the port area with a varying

elevation of -12m to -62.5m ACD.

A summary of the geotechnical conditions gathered during previous geotechnical studies is

provided in Table 8 below.



6-15

TOP ELEVATION (m CD)

DESCRIPTION sat

(kN/m3) c

0 Fill 17 0 30

-13.5 Natural Deposits 18 0 33

Table 8: Soil Properties for Container Terminal

Notes:

sat = Soil saturated unit weight c = drained cohesion

= drained effective friction angle

6.4.3 Site Hydrogeology and Hydrology

6.4.3.1 Site Hydrogeology

The hydrogeology of a site pertains to the underground water features.

As per the Hydrology Data Book (2000 2005), the project area lies within the coastal area

of sea water intrusion, outside aquifer V of the Northern Plains for Mer Rouge area and

aquifer II of Phoenix/Beau-Bassin: Albion-Moka/Coromandel for Fort William area.

6.4.3.2 Site Hydrology

The hydrology of a site pertains to the surface water features.

As per the Hydrology Data Book (2000 2005), the project area lies within the catchment

area of Port Louis (catchment XY) of an extent of 51km as shown in Figure 18 below.



6-16

Figure 18: Port Louis Catchment Area

There is no information specific of this catchment area in the documentation.

Rivers flowing in the project area have been identified as follows:

South of the project site: Lataniers River and the Old Moat flowing to Trou Fanfaron basin. These water features are located 1.4km from the MCT quay and will not be

affected by the development

North of the project site: Rivulet Terre Rouge. The rivulet proper is located 1.3km from the MCT quay and will not be affected by the development

Rivulet Terre Rouge Estuary which is the interface between fresh and sea water is located some 600m from the MCT quay. The likelihood of any impact from the project

on the estuary is assessed further in the report.

6.5 Baseline Data on Terrestrial Environment

6.5.1 Introduction

Land in the Port Area is extremely scarce and has been fully optimised; Mer Rouge area

mostly consists of reclaimed land and most of it has either been developed or earmarked for



6-17

port related installations, e.g. Mauritius Container Terminal, Mauritius Freeport Development

Co Ltd, the Petroleum jetty, the LPG storage facilities and coal storage area.

The terrestrial biodiversity in the core project area, i.e. 500m radius from the project site is

thus limited.

The outer project area, i.e. between 500m to 1000m radius from the project site, includes the

declared Environmental Sensitive Areas of (i) Rivulet Terre Rouge Estuary and (ii) Wetland

No 87 at Fort William, as furthermore developed in the next sections.

The area to be covered by the hardstand extension is currently covered with alien vegetation

and is deprived of any specific habitats and biodiversity.

An Ecological Survey was carried out for the purpose of the present EIA in the environmental

sensitive areas, results of which are presented below.

Aerial identification of zones and vegetation types was carried out with the help of Google

Earth Satellite Photographs. Ground surveys were also performed to identify the flora and

fauna present and to locate all native plants present. Available data on (i) Bird Count and (ii)

Fauna & flora in the RAMSAR site which were obtained from the Ministry of Agro-Industry

and Food Security was reviewed.

6.5.2 Classified Environmental Sensitive Areas

According to the Environmental Sensitive Areas Classification Report (ESA Report) of the

Ministry of Environment & NDU (2009), there are two wetlands systems - being coastal

freshwater and upland marsh systems - in the project area as shown in Figure 19 below,

namely:

Rivulet Terre Rouge Estuary Bird Sanctuary (wetland No. 178) Fort William marsh (wetland No. 87) which is classified as an isolated marsh with

nearest neighbour at 2,521m.



6-18

Figure 19: Wetland Systems (ESA Report)

6.5.3 Rivulet Terre Rouge Estuary Bird Sanctuary

The Rivulet Terre Rouge Estuary Bird Sanctuary (RTREBS), classified as a RAMSAR Site, is

situated at Mer Rouge near the village of Roche Bois and is only 2 km from the city centre of

Port Louis; Rivulet Terre Rouge Estuary is one of the largest estuaries found in Mauritius

Its main characteristics as a coastal/marine wetland are:

Intertidal mud/ sand flats Permanent shallow marine waters in most cases less than six metres deep at low

tide;

Estuarine system and waters; permanent water of estuaries

The sanctuary occupies an area of about 26 ha but does not occupy the whole of the

estuary. Its boundary is shown in Figure 20 below.

178

87



6-19

The Rivulet Terre Rouge buffer zone includes stretches of sandy areas surrounding the

wetland encompassing the foot trail to the mudflat and the mouth of the river entering the

sea.

Figure 20: RTEBS Site Location and Boundary Outline (in red)

It is unique on the island in the sense that it is an important wintering ground and refuge for

hundreds of migratory birds which escape the rigorous winter prevailing in the northern

hemisphere. Many of these birds come from Europe, Siberia and the Near East.

The site is important for the following habitats:

Estuarine and shallow marine waters; Intertidal mud, sand or salt flats; Three species of endemic plants; and Fourteen species of regularly visiting migratory birds



6-20

6.5.3.1 Flora

The site is known to harbour several species of flora which are either endemic to Mauritius or

indigenous to the Mascarene. The unique species Sesuvium ayresii (endemic to Mauritius

and Reunion Island) is thriving on the site together with a number of typically marshy plants

of the Cyperaceae family.

Weeding of the site has been undertaken and portions of the sanctuary have been replanted

with coastal indigenous and endemic vegetation. These include Barleria observatrix,

Hyophorbe lagenicaulis, Latania loddigesii,Diospyros egrettarum, Cassine orientalis,

Dracaena concinna and Stadmania oppositifolia.

Unfortunately, though alien invasive species are being removed, many of these plants such

as Tabebuia pallida, Pongamia pinnata, Pithecellobium dulce, Lantana camara and Senna

occidentalis are still found on the site with varying degrees of abundance.

6.5.3.2 Fauna

The estuary seasonally houses migratory birds that fly away from harsh northern winters

from as far off as Siberia to enjoy the warmer temperatures of the island. Birds start arriving

in September/October each year, their numbers reaching a peak in December/January. By

late February/March the birds have returned North.

The site is visited every year by about 1200 birds with 13 regular migrant species and 6 rare

migrants. All the 19 bird species are covered by the Ramsar Agreement.

The list of Migratory Birds and Marsh Birds obtained from the National Parks and

Conservation Services of the Ministry of Agro-Industry and Food Security is reproduced in

Table 9 below:



6-21

COMMON NAME FRENCH NAME SCIENTIFIC NAME FAMILY

Migrants

Common Ringed plover

Charadrius hiaticula Charadriidae

Greater Sandplover Pluvier de Leschenault Charadrius leschenaultii Charadriidae

Grey Plover Pluvier argent Pluvialis squatarola Charadriidae

Crab Plover Pluvier crabier Dromas ardeola Dromadidae

Common Sandpiper Guignette Actitis hypoleucos Scolopacidae

Ruddy Turnstone Tourne Pierre Arenaria interpres Scolopacidae

Sanderling Bcasseau sanderling Calidris alba Scolopacidae

Curlew Sandpiper Bcasseau cocor Calidris ferruginea Scolopacidae

Little Stint Bcasseau Minute Calidris minuta Scolopacidae

Eurasian Curlew Courlis Cendr Numenius arquata Scolopacidae

Whimbrel Courlis Corlieu/Corbijeau

Numenius phaeopus Scolopacidae

Common Greenshank

Chevalier Aboyeur Tringa nebularia Scolopacidae

Terek Sandpiper Bargette Cendre Xenus cinereus Scolopacidae

Lesser Crested Tern Sterna bengalensis Sternidae

Common Tern Sterne Pierre Garrin Sterna hirundo Sternidae

Resident

Little Green Heron Gasse Butorides striatus Ardeidae

Table 9: Migratory and Resident Birds found at RTREBS

The estuary is populated with a number of macro organisms like molluscs, crabs, worms and

bivalves upon which the migratory birds feeds.

6.5.3.3 Site Classification

Rivulet Terre Rouge Estuary was listed as a Category 1 high priority rating Ramsar Site of

International Importance on 30 September 2001. The Wetland Reserve status was

maintained for protection and conservation reasons.

The site was proclaimed an Environmentally Sensitive Area in the ESA Report (June 2009)

and approved by Cabinet. The rating was given in Table 10 below.



6-22

ID LOCATION

PROXIMITY DESIGNATION CATEGORY PI SCORE

VI SCORE

PRIORITY

39 Ruisseau Terre Rouge



6-23

6.5.4 Fort William Wetland

The location of Wetland No 87 is shown in Figure 22 below extracted from the Environmental

Sensitive Areas Classification Report of the Ministry of Environment & NDU (2009).

Figure 22: Wetland No 87 (ESA Report)

6.5.4.1 July 1997 Observations

The survey carried out by Diospyros Ltd in July 1997 showed that the plants found at the site

were Boerhavia coccinea, Atriplez halimus, L. var granulata Chevall, Paspalum distichum,

Phyllanthus tenellus, Sesuvium ayresii,Fimbristylis dichotoma (L) vahl, Cyperus rotondus.

The last three only are native but not threatened and of no significant conservation value at

the site.

An abundance of small fish locally called "million" was also found in the wetland. This is an

exotic fish and of no significance.

There were also some wading birds which can also be found at the other sites such as the

Terre Rouge estuary.



6-24

The assessment of the area in 1997 noted that the site at Fort William had lost its ecological

value. (ref: Gibb, 1997).

6.5.4.2 July 2011 observations

The survey carried out by Diospyros Ltd in July 2011 showed that piling up of sand has taken

place in the area and it is difficult to evaluate the degree of disturbance that has taken place

since 1997.

The wetland is at ground level and has an area of about one hectare. A ditch/canal branches

off the existing Canal all the way past the Coast Guards station where it exits to the sea. The

wetland site was dry except for this drainage ditch

It is vegetated with a small area of Typha domingensis (voune), Ipomea pes- caprae, a

variety of grasses and cyperaceae and a few Thespesia popullnea trees. Two native birds

were seen, one gasse or striated heron and one whimbrel.

6.5.4.3 Site Classification

Fort William is classified as a wetland of moderate conservation value (Category II ESA

designation as delimited in the Environmental Sensitive Areas Classification Report of the

Ministry of Environment & NDU (2009).

Given its inland location, wetland No 87 will not be affected by the proposed reclamation at

sea.

6.6 Baseline Data on Marine Environment

6.6.1 Introduction

The marine baseline was gathered from desk review of available data and from specific

surveys carried out for the purposes of the present EIA.



6-25

6.6.2 Wave Data

The wave climate in deep water off Port Louis is relatively quiet, with waves and swells from

open sea occurring approximately 10% of the time.

Offshore waves in the vicinity of Port Louis are predominantly from the west. Extreme wave

conditions are generated by cyclones, the severity of which is dependent upon the path of

the cyclone, the speed with which it moves, the pressure and wind speed.

A table of significant wave events in three-hour storms for inshore and offshore locations

presented by Sir Alexander Gibb & Partners 1993, prepared using MNIMET, is presented in

Table 11 below:

RETURN PERIOD (YEARS)

SIGNIFICANT WAVE HEIGHT (M) - OFFSHORE LOCATIONS

SIGNIFICANT WAVE HEIGHT (M) INSHORE

LOCATIONS (AT -25M CONTOUR)

SW WSW WNW NW NNW NNE A B C2

1 5.4 3.5 4.8 5.3 4.2 4.1 4.9 5.1 6.6

10 7.1 4.9 6.7 7.5 5.7 5.5 6.6 7.1 9.9

25 7.8 5.3 7.4 8.3 6.3 6.0 7.3 7.7 11.1

50 8.2 5.7 7.9 8.9 6.7 6.3 7.8 8.1 12.0

100 8.7 6.0 8.4 9.5 7.2 6.7 8.3 8.6 13.2

Table 11: Significant Wave Heights at Port Louis (Sir Alexander Gibb & Partners 1993)

Locations A, B and C are shown in Figure 23 below.

2 Waves from direction between 270 and 308 offshore are heavily focused by caustics near C



6-26

Figure 23: Location of points A, B and C (Sir Alexander Gibb & Partners 1993)

A wave buoy from the MPA recorded wave heights of up to 5.5m during cyclone Daniella at

20m depths. It is understood that, in terms of waves in Port Louis, cyclone Daniella was the

most severe cyclone.

Considering the several studies of waves at Port Louis, the values shown in Table 12 below

are recommended for design of berth structures.

LOCATION SIGNIFICANT WAVE HEIGHT Hs (m)

Berthing Structures 5.1

Revetments adjacent to berthing structures 5.1

Reclamation area (north), Fort George 3.4

Reclamation area (south), Fort William 1.0

Table 12: Recommended Design Waves

6.6.3 Tidal Data

The tides in Port Louis Harbour are semi-diurnal and have a range of approximately one

metre between extreme tides. The present day tidal data from Admiralty charts is presented

in Table 13 below:



6-27

TIDE REFERENCE ELEVATION (m ACD)

Mean High Water Springs MHWS 0.7

Mean High Water Neaps MHWN 0.5

Mean Sea Level MSL 0.44

Mean Low Water Neaps MLWN 0.4

Mean Low Water Springs MLWS 0.2

Table 13: Tidal Levels for Port Louis (Admiralty Tide Tables, Vol2)

6.6.4 Sediment Data

6.6.4.1 Marine Sediment Petrography

Petrographic examination of 5 seabed sediment samples was previously carried out as part

of the investigation for the then proposed New Container Terminal at Mer Rouge. (DDS

Irrigation,1996). All samples appeared to be fine-grained sands with variable amount of

organic carbon present. Samples rich in organic matter are characterized by a dark greenish

colour that is apparently irregular distributed in a light-gray sandy matrix (samples Mauritius-

11, Mauritius-12, Mauritius-22). Samples 6 and 18 appeared to be devoid of organic matter

and are characterized by a light gray to yellowish colour. All samples were found to be

composed of aragonite and Mg-calcite quartz, the feldspar mineral albite and a kaolinite-type

clay mineral were identified in tract amounts in some samples.

The relative weight of the three size fractions obtained by sieving illustrates clearly the

predominance of silt and fine sand as compared to coarse and very coarse sand, granules

and pebbles as summarised in Table 14 below. Four of the five samples are composed of

60-70% of fine sand or silt, and about 30-40% of coarse and medium sand. Coarser material

constitutes less than 1%. Only sample, 6 deviates from this pattern in that it contains less

than 10% of coarse and medium sand, but more than 90% of fine sand and silt. Samples rich

in organic matter contain slightly more coarse material than those devoid of organic matter.



6-28

SAMPLES NO

C (sediment size, g,

d>0.833mm)

M (g, 0.833 mm >d>0.180

mm)

F (g, d



6-29

SITE SIEVE SIZE (MM)

% RETAINED SITE SIEVE SIZE (MM)

% RETAINED

1 0.3 - 1.18 85.5 11 0.3 - 1.18 90.9

2 0.3 - 1.18 67.1 12 0.3 - 1.18 76.1

3 0.3 - 1.18 80.8 13 0.3 - 1.18 83.4

4 0.3 - 1.18 57.8 14 0.6 2.36 43

5 0.0075-0.3 46.7 15 25-50 85.4

6 0.3 - 1.18 66 16 0.3 - 1.18 79.3

7 0.15 0.6 97.4 17 0.3 - 1.18 54.1

8 0.3 - 1.18 53.4 18 0.6 2.36 85.1

9 0.15 0.6 91.3 19 0.3 - 1.18 73.9

10 0.6 2.36 82.7 20 0.6 2.36 86.5

Table 15: Sediment Size Characterisation



6-30

Figure 24: Location of Survey Sites 1 to 11 North Port Area



6-31

Figure 25: Location of Survey Sites 12 to 20 South Port Area

6.6.4.2 Marine Sediment Quality

The Terre Rouge Estuary and the nearby marine environment is known to have received a

number of waste water and similar discharges in the past, that may have impacted estuarine

sediments. Potential historical discharges include those from textile and dye industries,

sewage discharges, diffuse agricultural runoff and leachate from a landfill site situated at the

head of the Estuary. Many potential compounds associated with these types of discharges,

such as some heavy metals, biocides and pesticides, are of a persistent nature and can

remain for long periods within marine sediments. If such compounds and chemicals are

present in the areas to be dredged, they may be remobilised during the dredging and the

subsequent land reclamation process and negatively impact water quality, marine ecology

and human health.

No records of baseline marine sediment quality appear to be available for the proposed

dredge area or vicinity.

A marine sediment sampling and sediments analysis program to assess physical and

chemical conditions of the proposed dredge area and assess their suitability for use in the



6-32

land reclamation area, was commissioned by MPA and undertaken by Water Research Co

Ltd in late 2011. The program included:

22 sediment sampling sites within in the area to be dredged in front of MCT; 2 marine sites and 3 land based sites in the Terre Rouge estuary which are not to be

dredged;

10 land based sites in the material at Fort William to be used for the reclamation bund construction; and

7 marine sites off in the area to be dredged off Quay 1 in Port Louis Harbour.

The test results are presented and assessed in an interpretive report prepared by AECOM

(AECOM, 2012).

Figure 26 below - referenced as Drawings No. DD-SI-033 in the Drawing Section of the EIA

report - shows the marine based sampling locations in front of the MCT, the marine based

sampling location in the estuary and the land based sampling location in the estuary.

Figure 26: Location of Marine and Land based Sediment Sampling (MCT and Estuary)



6-33

Figure 27 below - referenced as Drawings No. DD-SI-034 in the Drawing Section of the EIA

report - shows the marine and land based sampling location at Fort William.

Figure 27: Location of Marine and Land based Sediment Sampling (Fort William)



6-34

Figure 28 below - referenced as Drawing No. DD-SI-035 in the Drawing Section of the EIA

report shows the marine sampling locations off Quay 1.

Figure 28: Location of Marine Sediment Sampling (Quay 1)

The material to be dredged in this project is not being dumped at sea but will be used

beneficially in bunded reclamation areas to create valuable additional port land at Fort

William and Fort George.

As noted in Section 3.3, Mauritius is a signatory to the Nairobi Convention for the Protection

and Management and development of the Marine and Coastal Environment of the Eastern

African Region, 2010.

In the absence of specific or detailed Mauritian Standards or Guidelines for sediment quality

of dredged material, and to comply with general requirements of the EPA (2002) as outlined

in Section 3.2, the obligations and general assessment guidelines from the London

Convention and Protocol have been used as a guide to assess sediment quality for the



6-35

proposed project component. These guidelines provide direction for dealing with the

dumping of dredged material at sea, as well as specific sediment chemical quality action

levels for dredged material in common use internationally

Results from the sediment quality testing have been compared against appropriate sediment

quality guidelines and standards to assess suitability for the intended beneficial use as

reclaimed land. In this respect the following guidelines for sediment quality have been

referenced:

OSPAR (2000, 2007)

UK CEFAS; and

Dutch (2008)

Ecotoxicological Assessment Criteria (EAC) as proposed by OSPAR (Oslo Paris Convention

for the Protection of the Marine Environment of the North-East Atlantic) are used for

monitoring of seabed sediments. The EAC provide a range of values for concentration levels

of substances above which concern is expressed. Generally the values given are provisional

and do not have legal significance.

The Dutch (2008) standards have long been internationally recognised for assessing the

chemical quality of dredged material and have, therefore, provided a benchmark against

which to evaluate the sediment quality status of material to be dredged. The UK CEFAS

guidelines have been included to provide an additional measure for compounds not included

in either of the first two guideline documents.

The OSPAR, UK and Dutch guidelines are used for assessing the suitability of dredged

material for unconfined disposal to open waters or a specific beneficial use and are

summarised in Table 16 below. It is noted that not all guidelines or standards exist for the

same substances. Generally, if sediment quality levels are below those indicated for the

lower level, the material is deemed to be suitable for unconfined ocean disposal.

For OSPAR, the lower EAC value is a concentration derived for protection of all marine

species from chronic effects, including the most sensitive species. The upper EAC is defined

as the highest (transient) concentration that is expected not to cause acute toxic effects.

Under the UK Action levels, Level 1 is the contamination level below which there

contaminants are considered to be of no concern and Action Level 2 is the level above which

the materials are considered to be unsuitable for disposal at sea. Where sediment chemical



6-36

quality falls between the two further assessments of risk is required to demonstrate minimal

impact to the environment and human health

Under the Dutch standards the Target Value is the level below which the risks to the

environment are considered to be negligible. The Intervention Level is the level of

contamination above which a serious case of soil contamination exists. If levels for priority

substances within a sample are exceeded, the material of the whole compartment

represented by the sample cannot be dumped at sea and must be stored on land.

Chemical

OSPAR UK Cefas Guidelines Dutch Standards (2009) EAC2 Action

Level 1 Action Level 2

Target Value

Intervention Level

Arsenic (mg/kg) 110 20 100 29 29 Cadmium (mg/kg) 0.11 0.4 5 0.8 4 Chromium (mg/kg) 10100 40 400 100 120 Copper (mg/kg) 550 40 400 36 60 Lead (mg/kg) 550 50 500 85 110 Mercury (mg/kg) 0.050.5 0.3 3 0.3 1.2 Nickel (mg/kg) 550 20 200 35 45 Zinc (mg/kg) 50-500 130 800 140 365 TPH C6-C40 (mg/kg) - - 1,250 PAH, Total Detected (g/kg) - - - 8,000 PCBs, Total ICES 7 (g/kg) 110 10 - - 100 Tributyl tin (g/kg)1 100 1,000 - 2,500 Triphenyl tin (g/kg)1 100 1,000 - 2,500 Dibutyl tin (g/kg) 100 1,000 - 2,500

Table 16: Standards and Guidelines for Assessing Contamination of Dredged Materials Notes: 1. There are no specific guidelines on levels for Triphenyl tin however as tributyltin and

triphenyltin compounds have similar effects on humans and organisms in the environment, the levels

for TBT have been adopted

2. Levels for OSPAR are provisional



6-37

Chemical analyses were undertaken on sediment samples that were collected during the site

investigation program conducted in late 2011. Sediment cores were taken and samples

tested for a range of heavy metals, polychlorinated biphenyls (PCBs), Total Petroleum

hydrocarbons (TPH), polyaromatic hydrocarbons (PAHs), a suite of tributyltin compounds

(TBT, TPT and DBT) and selected pesticides.

The results for each of the three areas from which material is to be taken and placed into the

reclamation areas are assessed separately below.

The level of pesticides in all areas is well below the OSPAR, UK and Dutch lower action

levels.

MCT Dredge Area

A total of 55 samples were tested across the 22 sample sites. For the 1,000,000 cum to be

dredged from this area, this equates to approximately one sample for each 18,000 cum.

The results are compared to the OSPAR, UK Action Levels and Dutch Standards in Table 17

below. With few exceptions the sediments proposed to be dredged showed relatively low

levels of impact from the tested metals and chemicals.

Overall, the average of each contaminant collected spatially over the area to be dredged was

below all of the lower action levels indicated in Table 16. Except as noted below, in all cases,

none of the sediments tested exceeded the OSPAR, UK Level 2 or Dutch Intervention

Levels.

There were two test results from samples in the northern part of the MCT dredge area that

exceeded the OSPAR and Dutch Nickel Intervention Level, 130mg/l at MS09 and 75.2mg/l at

MS11. The samples pass Action Level 2 under the UK guidelines.

Copper levels (50.3 mg/kg) at MS09 exceeded the OSPAR and UK and Dutch lower action

levels. At MS09 (54.3 mg/kg) and MS23 (47.5 mg/kg) the Chromium level of exceeded the

lower UK level.



6-38

Contaminant Average Maximum

OSPAR No. samples > UK Cefas Guidelines

No. samples > Dutch Standards (2009)

No. Samples

> EAC

Action Level 1

Action Level 2

Target Value

Interv. Level

Arsenic (mg/kg) 4.80 7.47 0 0 0 0 0 Cadmium (mg/kg) 0.10 0.253 0 0 0 0 0 Chromium (mg/kg) 16.83 54.3 0 2 0 0 0 Copper (mg/kg) 7.80 50.3 1 1 0 1 0 Lead (mg/kg) 4.45 21.7 0 0 0 0 0 Mercury (mg/kg)



6-39


OSPAR No samples > UK Cefas Guidelines

No samples > Dutch Standards (2009)

No. Samples

> EAC

Action Level 1

Action Level 2

Target Value

Interv. Level

Arsenic (mg/kg) 4.15 6.32 0 0 0 0 0 Cadmium (mg/kg) 0.08 0.131 0 0 0 0 0 Chromium (mg/kg) 4.80 48.6 0 1 0 0 0 Copper (mg/kg) 3.78 40.9 0 1 0 1 0 Lead (mg/kg) 1.82 2.4 0 0 0 0 0 Mercury (mg/kg)



6-40

The Chromium level at MS814 of 51.4mg/kg was above the UK Action Level 1 value of 40

mg/kg.

The Nickel level at MS814 of 48.1mg/kg exceeded the Dutch Nickel Intervention Level. The

sample passed Action Level 2 under the UK guidelines.

At MS814 and MS815 Triphenyl Tin readings were 203 g/kg and 112 g/kg respectively and were above the adopted Action Level 1.


OSPAR No. samples > UK Cefas Guidelines

No. samples > Dutch Standards (2009)

No. Samples

> EAC

Action Level 1

Action Level 2

Target Value

Interv. Level

Arsenic (mg/kg) 6.70 8.18 0 0 0 0 0 Cadmium (mg/kg) 0.12 0.409 0 1 0 0 0 Chromium (mg/kg) 23.18 51.4 0 1 0 0 0 Copper (mg/kg) 15.41 38.4 0 0 0 1 0 Lead (mg/kg) 13.33 36 0 0 0 0 0 Mercury (mg/kg)



6-41

6.6.5 Marine Water Quality

6.6.5.1 Seawater Water Quality

Water quality sampling and analysis was carried out in December 2010 for the purpose of the

present EIA. Water quality samples were collected at sampling locations shown in Figures 24

and 25. Results for the main physic-chemical parameters at the sampling stations are

reported in Table 20 below.

SITE PH DO mg/l

SALINITY /OO

T C

NITRATE mg/l

PHOSPHATE g/l

TSS mg/l

1 8.24 14.6 36 26.7 19.96 1.18 2.74

2 8.2 15.1 35 26.8 18.60 1.16 3.58

3 8.83 6.1 35 26.7 36.52 3.56 3.60

4 8.2 6.1 36 26.7 26.41 1.17 6.20

5 8.2 6.2 36 26.6 15.13 0.59 3.13

6 8.19 6.5 36 27 15.00 1.17 7.80

7 8.03 15 35 27 5.58 0.61 4.24

8 8.07 6.3 35 27 16.28 1.21 0.35

9 8.14 9.7 36 26.9 20.65 1.21 0.15

10 8.19 5.6 35 26.9 7.07 0.61 2.88

11 8.15 5.8 36 26.9 14.88 1.21 3.07

12 7.91 20.1 36 26.8 14.69 1.17 3.08

13 8.18 18.8 35 26.9 4.53 0.61 1.40

14 7.57 17.0 36 27.1 21.08 1.77 4.92

15 7.75 16.7 35 27.5 5.39 0.63 1.50

16 8.15 17.1 36 27 4.65 0.58 2.91

17 8.13 16.9 36 27 4.84 0.60 3.58

18 8.15 15.2 35 26.9 6.76 0.60 3.22

19 8.12 16.5 36 27 89.09 4.73 8.46

20 8.16 15.8 36 27.1 7.07 0.60 1.50

DoE Guidelines3

7.0

9.0 > 2 - - 1.0

100

(0.1 mg/l) 15

Table 20: Seawater Quality at Survey Sites

3 Guidelines for Coastal Water Quality (Department of Environment) D Industrial Areas



6-42

The concentration of nitrate in seawater samples fluctuated between 4.53 mg/L at site 13 to

89.09 mg/L at site 19. Nitrate concentrations at all sites sampled were well above the set

guideline levels (1.00 mg/L maximum for industrial areas) for the standards for coastal water

quality in Mauritius shown in table 20 above (Ministry of Local Government and Environment,

1999).

Although the high nitrate levels recorded during the survey of December 2010 may be

partially explained by known discharges from households, industries and agricultural sources

to the various rivers and rivulets in the vicinity, the results recorded are still higher than would

be anticipated.

Phosphate surface sea water values varied between 0.00058 mg/l at site 16 and 0.0047

mg/L at site 19. All samples were well below the guideline levels for industrial areas (0.1

mg/l) for the standards for coastal water quality in Mauritius shown in Table 20 above

(Ministry of Local Government and Environment, 1999).

Total suspended solids in seawater samples varied between 0.15 mg/L at site 9 and 8.46

mg/L at site 19. The established norm for suspended solids is 15 mg/L (Guidelines for

Coastal Water Quality Ministry of Local Government and Environment, 1998 shown in Table

20 above and attached at Appendix B). Site 6 had higher values and the rest of sites lower

values than recommended standard.

6.6.5.2 Rivulet Terre Rouge Estuary Water Quality

The information provided in this section has been obtained from the Fisheries Division of the

Ministry of Agro Industry and Food Security.

Water quality monitoring in the Rivulet Terre Rouge Estuary is undertaken on a weekly basis

by the Fisheries Division of the Ministry of Agro Industry and Food Security.

Results obtained from the Fisheries Division at two locations for the months of September

2008, June and July 2009 are summarised in Table 21 below:



6-43

STATION TEMP c

SALINITY ppt

PH DO mg/l COD mg/l

NO3-N mg/l

PO4 mg/l

September 2008

Bird Sanctuary 1 26 32.5 8.3 9.1 1.0



6-44

Site No

Depth (m)

Horiz. visibility

(m)

coral cover

(%)

algae cover

(%)

bare substrate

(%)

No coral spec.

observed

No fish spec.

observed

Total No. fish

countered

1 11 7 24 53 24 30 18 109

2 9 7 18 56 26 17 19 193

3 12 5 22 61 18 24 30 182

4 6 3 17 69 15 12 24 1320

5 5 1 11 80 10 13 17 209

6 5 1 1 84 16 4 13 137

7 4 5 12 57 32 7 10 196

8 0.8 1 3 97 0 4 5 17

9 1.5 5 0 93 7 3 11 72

10 7 5 4 73 24 13 18 113

11 5 3 10 80 10 17 25 1296

12 6 5 6 73 18 8 17 165

13 8 5 6 71 22 10 14 271

14 1.5 10 2 98 0 11 10 219

15 1.3 1 0 100 0 1 0 0

16 5 6 2 90 8 7 24 1149

17 2.5 7 1 87 12 6 16 278

18 4 5 2 80 18 8 20 220

19 5 7 2 94 4 8 17 148

20 12 7 6 70 24 17 19 124

Table 22: Summary of marine biodiversity observations made at all sites during in-situ survey

A comparison of the above findings from the 2010/2011 dive surveys with prior surveys

carried out in 1995 shows that the marine environment has been heavily degraded over

these 16 years. The coral cover in the dredge area and at Fort George sites is on average

less than10% and no corals were found at Fort William site. Coral patches are found further

west.



6-45

The 2011 survey concluded that

The areas especially around Les Salines area at Fort William is massively covered with macroalgae and these are indication of poor water quality and reef health.

The area in close proximity to the container terminal appears to have been in similar condition from 1995 to present notwithstanding the fact that a large part has been

dredged and some land reclamation works have been made. The benthos in this area

is covered with a layer of silt which most likely comes from the rivulet Terre Rouge.

In general, the area from Baie du Tombeau to Pointe Aux Sable is in a degraded state mainly due to the fact that the water quality in the area is relatively poor. The

turbidity of the water along with discharge from several streams and re-suspension of

fine sediments caused by ships further contributes to this poor water quality and

eventually to the relatively poor reef health.

The individual coral colonies that are present in the area are in relatively good health but these are small in size and their coverage is quite minimal. It should be pointed

out that the species observed in the areas surveyed are of the resistant and resilient

type which eventually explains their presence and the fact that they are thriving well.

In the areas where dredging works were undertaken in the past, new colonies of

corals are now seen to grow but these remains of the encrusting and massive type.

The reef health immediately north of the studied area is relatively better and with a greater coral cover than in the southern area. This could be for the fact that there

exist a residual tidal current that goes south along the western coast of Mauritius and

thus the pollutants, nutrients and suspended particles rich water moves generally in a

southern direction.

The fish present were mainly herbivores with a marked presence of those from the family of Chaetodontidae, Pomacentridae, Acanthuridae, Scaridae and Mullidae. Only

rare individual of carnivores were observed in the area and no predators have been

seen. The complete food chain in terms of fish is not present in the area. The number

of fish present in the area is relatively low as compared to much healthier reefs

around Mauritius and this further shows that the health of the reef is relatively poor.



6-46

Based on the findings of the dive survey, a Sensitivity Map of the area based on the

biodiversity and reef ecology was drawn for the North Port Area as shown in Figure 29

below.

Three zones were identified, namely:

Zone A, The Terre Rouge Rivulet Estuary, classified as sensitive with respect to its classification as a Ramsar Site and hence measures should be taken to avoid

disruption of the sensitive ecology at this particular site.

Zone B, representing the area of reef in the northern part of the port. This area is not considered very high sensitivity especially when compared to the other regions of

Mauritius. However the reef health is relatively better in this zone as compared to

other sites in the area and should be protected where necessary (in other words in

the case of polluting activities in the vicinity which may impact the area).

Zone C is not sensitive ecologically as biological characteristics as shown above is minimal for that area. This part is however sensitive hydrodynamically and as such

effort to maintain the dynamics in the areas should be made. It would be damaging to

this region to be clogged or saturated with sediments from the construction and

dredging work.



6-47

Figure 29: Sensitivity Map - North Port Area



6-48

No Sensitivity Map was drawn for the South Port Area (refer Figure 25) as no sensitive areas

could be identified except for the coral reef flat which was found not to be very healthy.

6.7 Air Quality and Noise

6.7.1 Air Quality

The information provided in this section is extracted from the Digest of Environment Statistics

prepared by the Central Statistics Office.

The Ministry of Environment and Sustainable Development has both stationary and mobile

air quality monitoring stations that have been operational since 2001. The main pollutants

under investigation are Dust (PM 10), Dust (PM 2.5), Black Carbon, Sulphur Dioxide,

Nitrogen Dioxide and Carbon Monoxide.

The results for all the pollutants under study at Medco Cassis fixed station and mobile

stations are reported when available in Table 23 below:



6-49

Ambient air

quality standard4

Medco Cassis 2003 & 2004 (fixed)5

Mer Rouge 2005 (Mobile)

Min Max 24hr Av for

yr

Min Max 24hr Av for

yr Pollutant

Units

Dust (PM10) g/m3 100.0 10.0 119.2 25.0 19 119 25 Ozone (O3) ppb 46.7 0.0 24.0 15.0 8 26 15 Sulphur dioxide (SO2) ppb 70.0 0.0 4.0 0.9 7 3 Nitrogen Dioxide (NO2)

ppb 97.5 0.0 27.0 9.0 11 27 9

Carbon Monoxide (CO)

ppm 8.0 1.0 1.6 1.2 0.15 8 0

Total Suspended Particles (TSP)

g/m3 150.0 29.6 107.5 56.4

Lead g/m3 1.5 0.0 0.0 0.0

Ambient air

quality standard6

Terre Rouge Nov/Dec 2008 (Mobile)

Aapravasi Ghat Nov/Dec 2009 (Mobile)

Min Max 24hr Av for

yr

Min Max 24hr Av for yr

Pollutant

Units

Dust (PM10) g/m3 100.0 6.5 14.9 10.9 Dust (PM25) g/m3 N/A 3.5 5.2 4.2 Black Carbon g/m3 N/A 1.0 3.0 2.0 Ozone (O3) ppb 46.7 Sulphur dioxide (SO2) ppb 70.0 3.0 7.0 Nitrogen Dioxide (NO2)

ppb 97.5 4.5 11

Carbon Monoxide (CO)

ppm 8.0 1.28 1.9

Total Suspended Particles (TSP)

g/m3 150.0

Lead g/m3 1.5

Table 23: Air quality monitoring at fixed and mobile stations

Note: No location map of the monitoring stations has been obtained; however Medco Cassis

and Aapravasi Ghat are known locations.

4 24-hour standard except for Ozone, Carbon monoxide and lead which are based on 1 hour , 8 hour

and 3 month averages respectively. 5 Medco Cassis : 2003 data for Dust PM10, NO2, TSP, Lead 6 24-hour standard except for Ozone, Carbon monoxide and lead which are based on 1 hour , 8 hour and 3 month

averages respectively.



6-50

All monitoring stations showed that the levels of ambient pollutants for the 24 hour averages

were well below the norms shown on the 3rd column of Table 19 above and attached at

Appendix B (Environment Protection (Standards for Air) Regulations 1998).

It can be derived from the above that the overall quality of the ambient air in the monitoring

areas is at a good and permissible level.

6.7.2 Noise

An ambient noise survey was commissioned for EIA purposes and was carried out in May

2011; results of which are reported below.

The purpose of the ambient noise monitoring was:

(i) To measure environmental noise levels during day and night at predetermined monitoring stations around the MCT area, and more precisely to:

a. Evaluate the contribution of MCT activities within the background noise

b. Evaluate the noise level at RAMSAR Site

c. Evaluate the noise level at the closest residence (Baie du Tombeau)

(ii) To compare measured noise levels to prescribed environmental noise exposure

limits in Mauritius (GN17/1997) in residential areas

(iii) To enable further modelling to be carried out for the assessment of the likely noise

level at the selected locations once the quay has been extended

The ambient noise monitoring enabled the evaluation of the noise level at three

predetermined locations relevant to the proposed project shown in Figure 30 below, namely

stations ST2 to ST4, around the MCT during three typical conditions, namely:

Day monitoring when there was no activity at the MCT Day monitoring when there was activity at the MCT Night monitoring when there was activity at the MCT



6-51

Figure 30: Location of Noise Monitoring Stations (Enviro-Consult Ltd)

Station ST2: Evaluation of the background noise level at the future boundary of MCT after extension of quay; noise will be the contribution of the existing Container

Terminal facilities and neighbourhood activities within the background of sector 1 of

the port area (towards Rivulet Terre Rouge). ST2 is located 355m from the quay

o Mean Noise level: 44dB(A) Leq day & night o Day noise levels with or without activity at MCT are comparable; which

demonstrates that noise level at this location is not primarily influenced by

MCT activities

o Noise contributors during day time at station ST2 are neighbourhood and natural contributors

o Noise levels at night were higher than during the day; the contributors during night time at station ST2 are natural contributors being the crickets

Station ST3: Evaluation of the noise level at RAMSAR Site. Monitoring station ST3 was located on the mud flat - where migratory birds are found and it is the closest

area from the MCT as per the recommendation of the National Parks &

Conservation. ST3 is located some 740m from the quay

MCT

Baie du Tombeau

Roche Bois area

Freeport Zone

RTREB



6-52

o Mean Noise level: 45 dB(A) Leq during the day with or without activity at MCT o Day noise levels with or without activity at MCT are comparable; which

demonstrates that noise level at this location is not primarily influenced by

MCT activities

o Noise level at ST3 is higher than ST2 which also demonstrates that noise level at this location is not primarily influenced by MCT activities

o Noise contributors during day time at station ST3 are primarily natural contributors being the birds on the mud flat and occasional neighbourhood

contributors being from fishermens boats on the estuary

Station ST4: Evaluation the noise level at the closest residence being in Baie du Tombeau area. ST4 is located some 705m from the quay

o Mean Noise level: 42.5 dB(A) Leq day & night, with or without activity at MCT o Noise levels obtained at this location shows that the noise level at this

location is not primarily influenced by MCT activities

o Noise contributors during day time at station ST4 are primarily neighbourhood contributors

o Noise levels at night were higher than during the day; the contributors during night time at station ST4 are natural contributors being the crickets

o Noise level at this residential location are within standards both during day time (60 dB(A) Leq) and night time (55 dB(A) Leq

o Noise levels obtained at ST4 once the quay has been extended will not exceed the prescribed limits of industrial noise towards residential

neighbourhood

The mean noise levels for monitoring station ST2 to ST4 is summarized in Table 24 below

and compared to prescribed environmental noise exposure limits shown on the 6th column of

the table and attached at Appendix B (Environment Protection (Environmental Standards for

Noise) Regulations 1997).



6-53

STATION LOCATION

LOCATION TYPE

PERIOD No activity at MCT

07 May 2011

Activity at MCT

12 May 2011

Environmental Noise Exposure Limit (industrial)

Noise levels in dB(A) Leq

ST2 MPA boundary

Day 43.7 43.1 60

Night --- 45.3 55

ST3 RAMSAR Day 45.0 45.1 60

Night --- --- 55

ST4 Residential Day 42.4 39.8 60

Night --- 45.4 55

Table 24: Mean Noise Levels at Monitoring Stations

The legislation provides an environmental noise exposure limit for industrial noise in

residential areas (refer column 6). There are no standards for industrial noise in non

residential areas; however, the same standards have been used here to assess the noise

levels recorded.

Based on the above, the noise levels obtained at all stations are within standards both during

day time (60 dB(A) Leq) and night time (55 dB(A) Leq).

6.8 Built environment

6.8.1 Socio-Cultural Conditions

The population of Mauritius, according to the Central Statistics Office of the Ministry of

Finance and Economic Development (MFED), was estimated at 1,233,669 in July 2004

based on 2000 Census. Salient features of the Mauritius Demography are:

according to the medium variant population projections, the population of Mauritius will grow from 1,186,873 in 2000 to around 1,486,000 in 2040, at an

average annual rate of 0.56%;

a sex composition of the population, that, from a slight excess of males over females in 1972, has reversed in 1983, to reach 610,294 males against 623,375

females in 2004, giving a sex ratio of 97.9 in 2040 due to lower mortality prevailing

among female;



6-54

the Republic of Mauritius, with a total land area of 2,040 square kilometres, had a population density of around 605 per square kilometres in mid-2004.

6.8.1.1 Existing Settlements

The existing settlements and population - as per census 2000 - within the project area are

provided in Table 25 below:

CLUSTER SETTLEMENT/ VILLAGE COUNCIL AREA

POPULATION (CENSUS 2000)

AREA

Greater Port Louis

City Proper 127,855 Inner core

North:

Baie du Tombeau

Terre Rouge

Le Hochet

12,011

8,736

13,878

Inner core

Outer core

Outer core

South:

Pailles

Pointe aux Sables/La tour

Koenig

9,954

16,448

Outer core

Inner core

Table 25: Existing Settlements in the Project Area

The catchment area was divided into:

An inner core with settlements located in or adjoining the area of environmental influence

An outer core with settlements located outside the area of environmental influence

The closest residential suburbs of Port Louis to the proposed development site are Roche

Bois and Baie du Tombeau. Roche Bois residential areas are located east of the Freeport

development; the closest being the Roche Bois CHA Estate which is separated from the

Reclaimed Land at Mer Rouge by a land stretch about 200 metres wide. Within the Roche

Bois residential areas there are numerous industrial, agricultural and commercial activities.

Industrial activities include a Tannery, Textile processing plants, a match factory and

workshops for automobiles, carpentry and panel beating. There are also pig farmers close to



6-55

Rivulet Terre Rouge and historically an animal quarantine station, which has been the main

source of complaints from the local inhabitants.

The Baie du Tombeau Residential area is located north of the proposed development site on

the other side of the Rivulet Terre Rouge Estuary. The Docker's Flats along the bank of the

estuary have now been decommissioned and the buildings have been demolished leaving

place to a vacant grassy land which is regularly maintained. Other residential areas close to

the Terre Rouge Estuary are Elisabethville and La Cocoterie. Baie du Tombeau forms part of the Terre Rouge Village Council Area which includes Bois Marchand, Terre Rouge, Riche

Terre, Le Hochet and Baie du Tombeau.

The Baie du Tombeau Residential areas also include various industrial activities such as

textile dye houses viz., St Malo Exports Ltd, Original Confection Ltd, Tropic Knits Ltd. among

others. A Rum Bottling Plant (New Goodwill Co Ltd) and other Garment Manufacturing plants

are present as well. There are also a number of workshops from automobile repairs to wood

carpentry and scrap/metal shops.

6.8.1.2 Social Infrastructure

All social infrastructures are available in the greater Port Louis area, namely:

Community/social Education Health Leisure Religious Sports

The shopping, hotel and leisure facilities, which form part of Le Caudan Waterfront

Development, have been constructed relatively recently and have created an important focus

for tourist activities and shopping.



6-56

6.8.2 Socio- Economic Conditions

6.8.2.1 Population Characteristics

In comparison to other municipalities, the greater Port Louis has the highest population with

17% of the national population and 35% of the population of the conurbation being the

greater Port Louis & Plaines Wilhems (census 2000).

In terms of housing units, again the greater Port Louis has the highest percentage with

16.9% of the national housing units and 34% of the housing units of the conurbation (census

2000).

6.8.2.2 The Economic Situation

The greater Port Louis contains 5,064 workplaces which represents 26.6% of the national

workplaces which is about 50% of the number of workplaces of the conurbation.

The annual intercensal increase (1990-2000) is of 1.6% for the greater Port Louis and a

breakdown of +0.8% for the city proper, +4.7% for the outer area North and +5.3% for the

outer area south.

Business activities in Port Louis

Port Louis remains the primary administrative and commercial centre for Mauritius but it

faces increasing competition from other urban centres, particularly the Plaines Wilhems

towns. A decentralisation trend is being experienced from within the city where both

population and the level of non-residential floorspace permissions have declined over the last

few years.

Statistics on business activities undertaken in the Island of Mauritius for the period July 2009

to June 2010 show that the total number of licences as at June 2010 was to 101,697,

representing an increase of around 7% over the figure of 94,609 as at end of June 2009.

During the period July 2009 to June 2010, some 9,798 new licences were issued, the

majority of which (6,542 or 67%) was in the industry group Wholesale and retail trade; repair

of motor vehicles, personal and household goods. For the period under review 2,710

licences were cancelled.



6-57

Adjusted licences and registrations by industry group for Port Louis as at June 2010 as

provided in Table 26 below:

NSIC INDUSTRY GROUP NUMBER

D Manufacturing 1,287

F Construction 186

G Wholesale and retail trade, repair of motor vehicles, personal household goods

12,260

H Hotels & restaurants 929

I Transport, storage & communication 4,123

J Financial intermediation 154

K Real estate, renting & business activities 2,491

M Education 304

N Health & social work 158

O Other community, social & personal services 741

Table 26: Adjusted licences and registrations by industry group

The Port

The Mauritius Ports Authority (MPA) operates the port which lies within the city limits of Port

Louis, north west of the Central Business District, but from which it is effectively severed by

the dual carriageway north-south M1 motorway running along the Caudan Waterfront. The

MPA is a major land owner and the port plays a vital role in the economy of Port Louis and

the country as a whole, since it handles 99% of the country's imports and exports.

Coastal Activities

Coastal activities National overview In addition to the creation of the Marine Parks Balaclava Marine Park (485 ha) and Blue Bay

Marine Park (353 ha) - , proclaimed under the Fisheries Act and the National Park and

Wildlife Act., six Fishing Reserves were proclaimed under the Fisheries Act in 2000. Within

these Fishing Reserves restrictions are placed on activities to protect fish stock, breeding

grounds and sensitive marine ecosystems.



6-58

These Fishing Reserves are as follows:

Port Louis Fishing Reserve 331 ha; Poudre dOr Fishing Reserve 2,542 ha; Poste Lafayette Fishing Reserve 280 ha; Trou dEau Douce Fishing Reserve 574 ha; Grand Port Fishing Reserve Zone A 1,716 ha and Zone B 112 ha; Black River Fishing Reserve 787 ha.

The Fishing Reserves not only assist in replenishing fish stocks within the marine ecosystem

but also protect the livelihood of local fishermen.

Data from the artisanal fishery at national level was gathered from the Annual Report 2009 of

the Fisheries Division. The data was collected monthly from 25 fish landing stations selected

randomly from the 61 existing ones around the island to estimate the catch and effort by fish

species and gear.

The catch was estimated at 820 tonnes in 2009 and comprised 496 tonnes from the lagoon

and 324 tonnes from off-lagoon.

The average catch per fishermen-day (CPFD) was 6.4 kg.

Coastal activities in the Project Area

There are two Fisheries Posts in the project area, namely:

Tombeau Bay Fisheries Post which includes Tombeau Bay and Roche Bois Fish Landing Stations

Pointe aux Sables Fisheries Post which includes Bain des Dames and GRNW Fish Landing Stations

The number of registered fishermen for the two above-mentioned areas, according to the

Annual Report 2009 of the Fisheries Division, is provided in Table 27 below:



6-59

FISHING GROUND NUMBER OF FISHERMEN

Code Definition Pointe aux Sables Areas

Tombeau Bay & Roche Bois

Areas

Total

L Lagoon 2 0 2

L/OL Lagoon/off lagoon

82 48 130

OL Off lagoon 80 95 175

Total 164 143 307

Table 27: Number of Fishermen in the Project Area (Fisheries Division, 2009)

There are 2 registered fishermen fishing in the lagoon only and 130 fishermen fishing both in

the lagoon and off lagoon.

Data from the artisanal fishery in the project area, obtained from the Ministry of Fisheries for

the two above-mentioned areas for the year 2010 is provided in Table 28 below:

AREA CATCH (KG) FOR YEAR 2010

CPFD (KG) FOR YEAR 2010

Baie du Tombeau 4,222 5.9

Roche Bois 2,466 5.2

Bain des Dames 2,830 4.2

Grand River North West 2,124 3.5

Pointe aux Sables 1 8,112 3.5

Pointe aux Sables 2 Not sampled --

Table 28: Catch & CPFD in the Project Area (Fisheries Division, 2009)

The average catch per fishermen-day (CPFD) in the project area is lower than the national

average.

It should be recalled that in accordance with the Ports (Operations and Safety) Regulations

2005, fishing is not permitted within the limits of a port.



6-60

Data on the abundance of fish in the project area was gathered from the Annual Report 2009

of the Fisheries Division; data is provided in Table 29 below:

SITE/TYPE OF REEF

YEAR POMACENTRIDAE & CHAETODONTIDAE

ACANTHURIDAE LABRIDAE SCARIDAE

Baie du Tombeau Back reef

2008 >1000 0-10 0-10 Not

observed

2009 >1000 Not observed Not

observed

Not

observed

Pointe aux Sables Back reef

2008 50-100 10-50 0-10 10-50

2009 Not observed Not observed Not

observed

0-10

Pointe aux Sables Fore reef

2009 0-10 0-10 10-50 0-10

Table 29: Abundance of Fish in the Project Area (Fisheries Division, 2009)

Common names of the above mentioned fishes are provided in Table 30 below for ease of

reference.

FISH SPECIES COMMON MAURITIAN NAME

Pomacentridae demoiselle

Chaetodontidae pavillon

Acanthuridae chirurgien

Labridae columbine

Scaridae cateau

Table 30: Common Names of Fish Species Observed



6-61

6.9 Services

6.9.1 Water Supply

The Central Water Authority (CWA) is responsible for the supply of potable water across the

country.

The water supply for the MCT extension works will come from the existing supply of the

MCT.

The expansion to the container terminal will not have a significant impact on the water

requirements of the site. A new toilet block is proposed at the north of the site. The new toilet

block will require water and a septic tank.

6.9.2 Electricity Supply

The Central Electricity Board (CEB) is responsible for the supply of electricity across the

country.

The existing electrical distribution system to Mauritius Container Terminal (MCT) consists of

a double-ended switchgear fed by two 22kV lines. These lines are served by C.E.B. and

originate from Fort Georges Power Station.

The available electrical power supply from the power station to MCT is 10MVA. Based on the

anticipated loads, it is apparent that there is sufficient power supply from the current 10MVA

supply without the need for future increase in supply from CEB

6.9.3 Sewerage System

The Wastewater Management Authority (WMA) is responsible for the collection and

treatment of wastewater in sewered areas.

The existing Container Terminal is not connected to the national sewerage network and

therefore has its own on site disposal system.



6-62

6.9.4 Solid Waste

Domestic Solid waste generated within MCT includes domestic waste, maintenance material

waste and ships waste.

Domestic waste is collected by the scavenging units of each municipal or district council

areas and disposed of at Mare Chicose Landfill site.

Maintenance waste such as scrap metal, components and machinery would usually be

recycled where practicable.

Generally there is minimal ships waste as whilst in port container ships usually keep all

waste on board the vessel. Any ship generated waste is collected by a specialist contractor

working under a contract with MPA.

6.9.5 Hazardous waste

Liquid or solid hazardous wastes are handled separately and for some wastes can be

disposed of at Mare Chicose Landfill site.

Other hazardous wastes such as used oil are to be collected and collected by licensed use

oil carriers for further re-use or recycling.

6.10 Traffic

6.10.1 Marine Traffic

The proposed improvement of the container terminal i.e. strengthening the existing structure

to allow deepening of the berthing basin, extension of the quay structure and extension of the

hardstand area, find its justification in the increasing vessel dimensions rather than in the

increasing traffic forecast which stands at 3.7% growth per annum for the captive trade and

1% for the transhipment trade to the horizon 2030.



6-63

6.10.2 Terrestrial Traffic

The container terminal operates 24/7 all year round. The terrestrial traffic is directly linked

and proportional to the marine traffic and consists mainly of container trucks loaded with 20

and 40 containers.

The access to the container terminal is off the M2 motorway at Mer Rouge roundabout.

Based on the above historic cargo growth, the terrestrial traffic growth would be in the same

range and would have no bearing on the current Level of Service of M2.

The Level of Service (LOS) of M2 is directly linked to the working hours and varies from LOS

A during the week-ends i.e. traffic and roadway conditions with little or no restriction in

manoeuvrability due to the presence of other vehicles, and drivers can maintain their desired

speeds with little or no delay - to LOS B, C, or D during week days off peak hours i.e.

conditions with increasing restrictions in manoeuvrability while still maintaining unstressed

traffic mobility to LOS E i.e. traffic flow at or near capacity or even LOS F i.e. forced

flow operation at low speeds during the morning peak hours.

The classification of Levels of Service is provided in Table 31 below.

LEVEL OF SERVICE

FLOW CONDITIONS

A Free flow conditions. Individual users are virtually unaffected by the presence of others in the traffic stream

B In the range of stable flow, but the presence of other users in the traffic stream begins to be noticeable

C In the range of stable flow, but marks the beginning of the range of flow in which the operation of individual users becomes significantly affected by the interactions with others in the traffic stream.

D High-density, but stable, flow conditions. Small increases in traffic flow will generally result in the occurrence of operational problems at this level.

E Operating conditions at or near the capacity level of a given facility. Operations at this level are usually unstable, because small increases in flow or minor disturbances in the traffic steam to breakdown.

F Forced or breakdown flow. This condition exists whenever the amount of traffic approaching a point exceeds the amount which can traverse the point. Queues form behind such locations. Operations within the queue are characterized by stop-and-go waves, and they are extremely unstable

Table 31: Classification of Levels of Service



6-64

The infrastructure upgrade works proposed in the context of the Road Decongestion

Programme prepared by the Road Development Authority will increase the manoeuvrability

on M2.

6.11 National Heritage

According to the National Heritage Fund Act 2003, there are 79 features listed as national

heritage of Mauritius in the Port Louis District.

Within the project area are found Fort George and Signal Tower (Harbour and Quays)

Outside the project area at almost 2 kms from the container terminal - is found the

Aapravasi Ghat and the remaining part of the structure comprising it; this heritage being

inscribed on the UNESCO World Heritage List.

Neither the proposed improvement of the container terminal nor the proposed land

reclamation will have a bearing on the national heritage of Mauritius.

6.12 Landscape and Visual Environment

The landscape character surrounding the port is dominated by infrastructure supporting the

port activities including access roads, warehouses, port security, offices, loading/unloading

facilities, fuel storage and bunkering. The closest residential area lies directly to the east of

the container terminal, between the terminal and the M2 highway.

A summary of the main landscape character in the vicinity of the port is summarised below:

Marine water frontage adjacent the harbour and quay operations Buildings, including warehouses, offices and equipment associated with the loading

and unloading facilities

Promenade areas, hotels, shops and restaurants at the end of the harbour Residential area to the east of the container terminal Fishing and recreational activity in Terre Rouge Estuary Rivulet Terre Rouge Estuary Bird Sanctuary

As shown on the location plan (figures 2 and 13), the container terminal is located some 1.8

kms from the motorway M2. Ground activities are not seen from inland; the cranes are on the

other hand well visible.



6-65

The container terminal is visible from Tombeau Bay area or from higher grounds and

constitutes one of the many activities in the Port Area.

The proposed improvement of the container terminal will have no significant additional visual

impact in an already dense harbour built environment.

chapt 6 - mauritius wind speed

Documents