EIA report for restoration of K Dhiffushi Harbour under construction of harbours for tsunami victims project

Abstract

This Environmental Impact Assessment (EIA) report is to fulfill the regulatory requirements under the Environmental Protection and Preservation Act of Maldives prior to the proposed harbor restoration at Dhiffushi in Kaafu Atoll. Dhiffushi harbor restoration project is part of the Construction of Harbors for Tsunami Victims Project. This restoration project involves repair of harbors at 10 islands. The project is funded by a joint loan taken from Islamic Development Bank (IDB), the Saudi Government and Organization of the Petroleum Exporting Countries (OPEC) by the government of Maldives. The design consultancy was awarded to Alhabshi Consultants Office, a Kuwaiti Company in association with Riyan Pvt Ltd (a Maldivian company). The Agreement for consultancy was signed on 6th November 2008 between the Government of Maldives and Alhabshi Consultant. Project proponent of the proposed harbor restoration project is Ministry of Housing, Transport and Environment. The project was bided as a design and consultancy project. The main design consulting company Alhabhsi Consultants is assigned to carry out the design works, preparing tender documents, carrying out EIAs and construction phase supervision consultant. The proposed development project involves renovation and restoration of Dhiffushi harbor. During the December 2004 Indian Ocean Tsunami, Dhiffushi harbor facility received extensive damages. These include damage to harbor protection walls, side walls and quay walls. Under the proposed project, new quay wall (concrete sheet piles, L section) and breakwaters (armor rocks) will be constructed at the existing foot prints. The harbor basin will also undergo maintenance dredging to -3MSL. The existing entrance channel will be reoriented to the deep passage between Meerufenfushi and Dhiffushi at the northern side. Since the proposed project is only a restoration project, basin size will not be increased. The concept plan is formulated in light of the new third generation harbor concept which is focused at functionality of the harbor. In this regard harbor usage components such as passenger embarking/disembarking, loading unloading area, fish landing, water and fuel recharging and mooring area will be demarcated. Dhiffushi is located north Male atoll, 36km from Male’. It is just about 0.37km from Meerufenfushi. In terms of geographic coordinates, it is located at 04° 26' 33" N and 73° 42' 49" E. Nearest inhabited island is Thulusdhoo approximately 9.4km south of Dhiffushi. The reef system hosting Dhiffushi and Meerufenfushi also hosts Kudavillingili (presently leashed for resort development). The reef system is approximately 12km long, 3.91km wide at the widest and 1.8km long at the narrowest area. The reef system has two deep lagoons, from which deep lagoon near kudavillingili is smallest. The deep lagoon near Dhiffushi is approximately 9.3km long separated by a small strip of shallow lagoon from the smaller deep lagoon. Numerous coral/rock heads are observed at the western side of Meerufenfushi and Dhiffushi at the deep lagoon area. The existing harbor facility is located at the eastern side of the island, while the entrance channel is located at the western side run between Meerufenfushi and Dhiffushi and run connected to northern side of harbor. The project boundaries are the harbor front area, either side breakwaters, deep passage between Meerufenfushi and Dhiffushi and entrance channel area. Under the proposed project maintenance dredging will be done at the basin and entrance area where necessary, while western side access point will be redirected to align to the deep passage. These activities will generate sediment plumes west wards. Dredged material removed during the maintenance dredging works will be disposed at the SE, NW and western central area of the (surplus after reuse during reconstruction work). The existing harbor footprint will not be changed due to the proposed project, breakwaters and quay wall will be constructed at existing foot print area (apart from small section of breakwater at the southern side of the harbor). Therefore the existing design of the harbor will remain as it is. The length of the harbor after completion of renovation works will be 188m and width 87m. The length of entrance channel is approximately 1030m, while width is 30m near harbor area and 50m at the northern side. The harbor basin will have a depth of - 3MSL after completion of the restoration works. The harbor will have a total length of 280m of breakwater. The breakwater also includes a 50m length area sheltering the boat yard area at the southern side of the island. Dredge material removed from the harbor basin (maintenance dredging works and entrance reorientation works) will be initially stockpiled near harbor area since part of the material will be required during construction works. Part of the sediment will be used for back filling the harbor front area and T Jetty areas. Sediment will also be used for construction of quay wall and breakwaters (geo-textile bags filled with dredged spoil. Approximately 5500m3 of sediment will be used for construction works while rest will be disposed at the erosion prone areas at the SE, NW and westerns central area of the island. The sediment will be transported to the disposal sites on trucks, although initially sediment will be stockpiled near harbor area for construction purposes. Approximately 31,000m3 of dredge material will be removed from the harbor basin and entrance channel. Existing environment was examined to identify significant environmental components that would be affected and to establish a baseline condition of the site. Available and relevant literature on environmental impacts associated with similar projects was evaluated to identify possible impacts. Oceanographic data and information on local hydrodynamics were qualitatively assessed to determine the current pattern around the island which was based on monsoonal wind patterns, wind generated waves, tidal flushing, geographic setting, the topography of the lagoon and shape of the shoreline. Three sites area surveyed for assessing the reef condition, site one was located at the eastern side of the island at a sea grass meadow, site two was located at the rock head in between Meerufenfushi and Dhiffushi while site was located at a knoll near the mouth of deep passage between Meerufenfushi and Dhiffushi. Live coral cover at site one and two was very low, while at site (knoll) live coral cover was approximately 15%. It is important to note that the most significant impact associated with the project would be impact on the marine environment from sedimentation. Dredging and excavation often carry a heavy load of sediments increasing sediment load in the water column causing discoloration due to suspended sediments of the impact area for a prolonged period. Since the project is a restoration project, the extent of sediment plum will be limited at the harbor basin area, whereas the entrance channel area two rock heads are needed to be deepened. The sediment plume is envisaged to be directed towards western deep lagoon. Since the proposed project is restoration project, environmental impacts associated with the proposed project are considered minor to moderate. The significant environmental components that are likely to be affected are the coral community established knolls at the deep lagoon due to maintenance dredging works. Mitigation measures are provided in the report for impacts that were categorized minor to moderate. Impact mitigation measures and monitoring is carried out to compare predicted and actual impacts occurring from project activities to determine the efficiency of the mitigation measures. It has to be noted that environmental monitoring has not been done since the completion of harbor, and extent of changes to habitat, live coral cover and shoreline is not known. Even though the project is not envisaged to cause impacts of shoreline (since construction will be done at existing footprint), it is important to monitor shoreline changes. The main issue raised in the consultation meeting at Dhiffushi by the IDC was the issue of entrance channel. According to the IDC the entrance channel segment at the northern side of the island was filled up and shallow even before the tsunami. According to the IDC the main reason for this is due to close proximity to the northern tip of island. At present community uses the natural deep passage between Meerufenfushi and Dhiffushi to access the eastern side of entrance channel. The IDC also stated that two rock heads at the deep passage has to be deepened to allow safe navigation during night and at periods when current is strong at the passage. With due consideration to main environmental components identified and the magnitude of impacts on these components from the proposed developments, the consultant concludes that the project components and designs are feasible and appropriate mitigation measures are given to correct and minimize unfavorable environmental consequences. Furthermore, the public and community consultation responses were in favor of the project due to the socio-economic benefits foreseen to the community from a functional harbor.