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6.
ENVIRONMENTAL IMPACTS AND THEIR MITIGATION
6.1.
CONSTRUCTION PHASE
Works to be carried out
Works to be carried out have been mentioned under section 2.2 of this report. Briefly, the following main
works are concerned:
 Road construction and potentially construction of temporary access roads;
 Construction of 4 roundabouts;
 Construction of roadside drains and other drainage structures;
 Construction of street lightning;
 Landscaping
These works will involve:

Earthworks / excavations;

Temporary stockpiling of excavated materials / topsoil;

Disposal of surplus excavated materials;

Import of fill material in the absence of appropriate volumes of excavated materials;

Construction of concrete / steel structures;

Plantations.
The equipment / plant to be used for such activities have been listed in Section 2 of this report.
Site Preparation and Clearance Operations
The initial stage of construction will involve the clearance of vegetation and removal of topsoil. As was
explained in section 4.1 of this report most of the Project site is occupied by sugarcane plantations and
smaller patches by secondary vegetation, including invasive exotic species. Some smaller patches that
are currently used for vegetable cultivation will also be cleared. The losses of these open spaces will
not affect significant natural areas or undisturbed natural or sensitive habitats of flora or fauna.
Therefore the impact of site losses on flora and fauna is not considered as significant and mitigation is
not required.
Clearance operations and site preparation have potential to result in the loss of top soil or to cause
mechanical disturbance. Mitigation can be achieved through timely and careful removal and proper
temporary storage of top soil at suitable locations. As construction proceeds the top soil should be reused in preparing the green spaces along the Project route for subsequent plantations.
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Establishment and operation of the contractor’s yard
Establishment and operation of the Contractor’s yard involves, inter alia,

Storage and handling of hazardous materials;

Soil & water pollution due to accidental or otherwise of fuel / oil spill

Solid Waste & Sanitation / Wastewater management;

Workshop operations.
Such operations, by their nature, have potential to cause soil and water pollution. To avoid / minimize
such risks, the Contractor shall submit the following plans to the Supervising Engineer, prior to
establishment of the contractor’s yard:

A location map and layout of the yard with details of the measures proposed to address
potential adverse environmental impacts resulting from its installation and operation in
compliance with all relevant legislation in force;

Soil & water pollution due to accidental or otherwise of fuel / oil spill to be avoided / minimised
through the use of dedicated areas for refuelling and washing of machinery / plant.
Contaminated soil shall be removed and disposed of as instructed by the competent authorities.

Solid Waste management plan consistent with applicable national regulations. Provide
information on the proposed organization of waste collection and disposal, provide
arrangements for various types of wastes (e.g. used oil, used tyres, etc.);

Sanitation / Wastewater Management plan consistent with applicable national regulations.
Provide information on the proposed supply of potable water and sanitation facilities , and
collection and disposal of wastewater .

Description and layout for equipment maintenance areas and lubricant and fuel storage facilities
including distance from any natural water sources. Storage facilities for fuels and chemicals will
be located away from watercourses. Such facilities will be bounded and provided with
impermeable lining to contain spillage and prevent soil and water contamination.
In selecting the site of his yard and to minimize the potential nuisance of local residents and guests of
the Holiday Inn Hotel during construction, the Contractor should consider prevailing wind directions as
well as the distance of his facilities from any sensitive receptors.
As regards the protection of water resources and in accordance with CWA policies, the Contractor
should note that the storage and handling of hazardous materials will not be permitted within a
perimeter of 500m from existing CWA boreholes. In any case, the contractor shall necessarily seek
CWA approval prior to such activities in the neighbourhood of any borehole.
Earthworks (Dust nuisance / muddy runoffs)
Earthworks will be carried out in relation to mainly

Road construction; and

Construction / relocation of services.
The large-scale exposure of cleared surfaces and soils and temporary storage of topsoil and other
materials at the site entail the risk to cause muddy runoff, especially during the rainy season. The
geology of the site provides some buffer for the potential effects of severe storms, however, in extreme
rainfall events the construction site may be subject to temporary flooding. Considering the distance of
the Project Area to the Blue Bay Marine Park it is assumed that there will be no immediate risk of
impacting this protected area through either direct or indirect drainage of silted storm water towards
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Blue Bay during severe rainfall. However, given the sensitivity of the site and the lagoon in general the
precautionary principle shall apply.
During dry periods and depending on the wind directions dust problems may occur as a result of
exposed soils and earth movement and storage. Dust nuisance may potentially affect neighbouring
residents at Plaine Magnien or Mare d’Albert, staff and guests of the Holiday Inn Hotel as well as
construction workers at the site. Plaine Magnien will face the greatest risk of dust impact during winter
when southeastern wind directions prevail. Due to its location in the immediate vicinity of the
construction site the Holiday Inn Hotel may be affected by construction traffic and dust nuisance
throughout the construction period.
Mitigation: Muddy run-off may best be controlled by a combination of seasonal restrictions for
earthworks and taking precautionary measures at the construction site – e.g. by providing settlement
ponds and / or bunds at strategic locations. Ideally the contractor should be required to prepare a
method statement on how he intends to avoid muddy run-off from the site at all times.
Top soil shall be removed at the start of operations and handled and stored such that it may
subsequently be re-used for landscaping.
Depending on rainfall and wind conditions dust control may be required. This may include spraying of
haul routes or other areas within the construction site. If materials need to be transported to or off the
site covered trucks should be used to avoid dust nuisance to airport users and staff.
Noise Pollution
Construction plant / equipment and movement of vehicles are likely to cause some noise nuisance.
Excessive noise levels on site represent a major hazard to site workers. If people need to shout to
make themselves heard over background noise from a site, background noise is likely to be about 75 –
80 dBA. Continued exposure to noise levels of 90 dBA can permanently damage hearing.
Mitigation: The contractor will ensure that all plant / machinery used for construction activities and
vehicles are well maintained and in proper running order. The contractor will ensure that no work is
carried out between 18:00 to 7:00 hours within 500m of any settlement or the Holiday Inn Hotel.
Air Quality
Exhaust emission from the operation of construction machinery will inevitably cause local air pollution.
Given the current conditions and land use at the site and the openness of the space it is concluded that
such impact will not be significant.
To generally minimize the level of air pollution the contractor will ensure that construction equipment is
maintained to good standards and avoid, as much as possible, idling of engines. The use of machinery
or equipment that cause excessive pollution shall be banned.
Spoil Management
Excavated materials unsuitable in the construction process and / or landscaping or excess excavated
materials shall be carted away within the shortest delay to sites approved by the competent authorities.
The Site Engineer shall ensure that same is executed by the Contractor. Timely carting away of spoils
will limit dust nuisance within and in the neighbourhood of the airport premises, and will reduce the risks
of muddy run-offs from the construction sites.
Soil Compaction
Earthworks and other construction activities will require the use of heavy plant / equipment including
trucks. The operation of such heavy equipment / plant shall be confined to specific pre-selected sites to
minimise soil compaction. Trucks used in the transport of construction materials, excavated materials
shall be confined to specific routes.
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Worker’s Health and Safety
The Contractor shall provide all staff and labour force with appropriate working gear and personal
protective equipment as required to minimize health and safety risks from direct or indirect sources at
the construction site.
Traffic Impact / Access
During construction, access to agricultural areas, individual facilities or residences may be temporarily
disturbed. To avoid such impact and related nuisance provisions have to be taken to ensure that
potentially affected people will be informed about the construction schedule at all times and that
appropriate alternative access is provided.
Proper planning of activities with access to the proposed road alignment from the M1 will ensure that
traffic flow along the existing route to and from the airport will not be affected.
6.2.
OPERATION PHASE
Traffic Forecast
For the purpose of forecasting future traffic on both the existing road and the project road, the project
road has been sub-divided into four sections as illustrated in the following Figure 6-1.
Figure 6-1: Sub-division of project road for traffic forecasts
Traffic studies associated with airport traffic and Omnicane proposed Development lead to the following
forecasts for horizon 2030 and 2065 : Figure 6-2, and Figure 6-3 :
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Figure 6-2: Traffic forecasts on existing airport road and proposed project road (Year 2030)
Figure 6-3: Traffic forecasts on existing airport road and proposed project road (Year 2065)
Figure 4-18, Figure 6-2 and Figure 6-3 clearly indicate the beneficial impacts resulting from the
proposed road, in so far as traffic flow and access security to and from the airport are concerned.
Noise Impact
The exposure limits for neighbourhood noise are provided in Schedule (Regulation 3) of the
Environmental Protection (Environmental Standards for Noise) Regulations 1997. According to the
above Regulation neighbourhood noise is defined as any noise other than industrial noise or noise
made by an aircraft, an animal or traffic. Therefore the (slightly less strict) standards for industrial noise
were used as a reference to assess the potential impact of traffic noise on the human environment.
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The relevant exposure limits for industrial noise as provided in the mentioned regulation are as follows:
07:00 – 21:00 hrs
60 dBA Leq
21:00 – 07:00 hrs
55 dBA Leq
Based on 2012 measurements in the area of the airport hotel and as was explained in section 4.1 of
this report, current noise levels in the Project area (i.e. the noise levels existing prior to the operation of
the Project) are within these limits.
Drainage
The construction of the proposed road will result in an area of 20 ha being made impermeable. During
torrential rains and especially during cyclones, runoffs from such impermeable surface will reach
extreme levels This stormwater runoff will need to be canalized and disposed of in such a way as to
ensure that any pollutant released on the road as a result of accident or accidental spillage (e.g. diesel,
fuel oil, kersosene, chemicals or alike) will not reach sensitive receptors such as the aquifer tapped by
CWA boreholes or the lagoon / Blue Bay Marine Park.
No roadside drain will be designed so as to outfall within a distance of 200m from the CWA pumping
station on the windward side of the road.
Mitigation: Given the absence of natural streams in the wider area the road embankment was raised so
as to ensure proper drainage over the embankments and side drains. These and the proposed
absorption pits have been designed for a 25y return period to ensure that peak flows can be discharged
safely