| Abstract: | The non-technical summary outlines the findings of the Environmental Impact Assessment
for the construction of a causeway of length 441m, linking Hoan‟dehdhoo and Madaveli and the
reclamation of 3.5ha of land area in Madaveli in Gaafu Dhaalu Atoll in the South of Maldives.
This project was earlier addressed through another EIA submitted in 2012 (SEAMARC, 2012),
though due to delays in implementation of the project, the EIA period is now void. Furthermore,
design of the causeway and changes to other components of the project, requires submission of a
second EIA for the project, prior to commencement.
The project proponent of the proposed project for coastal modification and construction of
causeway between Hoan‟dehdhoo and Madaveli is Ministry of Housing and Infrastructure while
the contractor for the project is Maldives Transport and Contracting Company Plc.The project includes two components:
1. Construction of a causeway linking the islands of Hoan‟dehdhoo and Madaveli. The
proposed causeway has a total length of 441m and width of 15m. The causeway between
the two islands will be constructed in two parts connected by the uninhabited island of
Haadhoo which lies in the shallow lagoon area between the two islands. Construction of
the causeway will be through reclamation of land area between the islands, whereby
stretch of land between Madaveli to Haadhoo is proposed to have a length of 261m, while
that between Haadhoo and Hoan‟dehdhoo is proposed to have a length of 180m. The area
will be reclaimed to a height of 1.4m above Mean Sea Level (MSL) and protected through
construction of a sand cement bag revetment along the whole length of both sides of the
causeway. Concrete culverts at 50m apart will be placed along the length of the causeway
to allow tide flow. The length of the culverts is equal to the width of the causeway (15m)
and 6m wide.
2. The second component of the project is the reclamation of 3.5ha of land at the
southeastern side of Madaveli. Reclamation of the land will be to a height of 1.3m above
MSL, using sand sourced from the lagoon area. Proposed borrow area for the project is
located at the eastern side lagoon between the two islands. A total of 73,500m3 of sand is
required for this work and the recommended borrow area is proposed to be dredged to a
depth of -3m from the seabed.Impacts on the environment from various activities of the project (both during construction
and operation) have been identified through interviews with the project management team, field
data collection and surveys and are also based on past experience of consultant in similar
development projects. Impacts which have been identified were analysed with the aid of a
Leopold Matrix, which gives numerical assessment of the magnitude and importance of an
impact.
The proposed project involves construction of a causeway between Madaveli and
Hoan‟dehdhoo and reclamation of 3.5ha of land area on the southeastern side of Madaveli. The
main construction stage impact associated with the project is due to dredging and reclamation
works, which have the potential to greatly impact the marine environment through direct habitat
loss and indirectly through sedimentation. Impacts discussed are;
Direct loss of habitat due to dredging and reclamation work
Sedimentation impact due to dredging and reclamation work
Mobilization of equipment and labor
Impact on vegetation due to causeway and road construction
Noise, vibration and disturbance to nearby residents
Impact on vegetation
Pollution of natural environment due to possible spillage, solid waste, disposal of
untreated waste water
Risk of accidents and pollution on workers and local population
The proposed borrow area is located at the eastern side of the reef between the two islands.
Dredging works is proposed to be undertaken using excavator and transported using interim
bonds. Dredging works at the borrow area will create sediment plume and expected to flow
eastwards (tidal currents). Sand bund is proposed around the periphery of dredging area hence
spread of fines will be reduced.
The causeway construction works will close the aperture between
Madaveli/Haadhoo/Hoan‟dehdhoo and stop flow of water. The culverts will be laid after
connecting the islands, hence sediment plume will be minor and only depend on tidal currents
(west to east on the eastern side of causeway). Impacts of sedimentation during causeway
reclamation are therefore categorized as moderate and short termed.
Significant negative impact on western side (southern side bay area of both islands) shoreline
and immediate land area adjacent to proposed causeway is envisaged in the operational phase. In
the event of storm surge (udha), water will pile up at the western side bay area causing rise of
water level consequently causing flooding. Even at present, periodic flooding is experienced
during SW monsoon due to storm surge. Therefore protection against storm surge is thought to
be less and negative impacts high due to current design of the causeway.
Mitigation measures for the various components which are expected to have impacts, have
been proposed in the report, including the recommendation to revise the current design of
causeway and include revetment at the southern side of reclamation area.
Given that this project is developed specifically for these two islands, an alternative location
is not considered. Alternatives for the project have been considered for the following;
Design of the causeway
Materials used to construct the revetment
Borrow location
Reclamation design
The no-project scenario is also considered, the environmental impacts which arise due to the
project such as change to hydrodynamics and loss of marine habitat and possible increase in
surge related flooding can be avoided. However, should this option be chosen, this means that
the social benefits (increased employment opportunities, easier travel between islands, better
public services and increased housing plots) provided by the project will be cancelled. Hence
given the high positive impact on the socioeconomic environment, discontinuation of the project
is not seen to be a feasible option. Although this may be the case, the current causeway design is
envisaged to increase surge related flooding hence this component is not feasible and needs to be
revised. Details of the various alternatives considered and the selected alternatives are shown in
Section 10 of the report.
The consultant concludes that the proposed project component, especially the causeway with
current design which lacks coastal protection measures in the vicinity of the causeway on either
island is likely to cause significant environmental damage (specifically coastal flooding) at both
islands. It is therefore recommended that an alternative design for the causeway should be
considered. |
