Environmental impact assessment : L. Dhabidhoo harbor development project

Abstract

This report discusses the findings of a social and environmental impact study undertaken by Water Solutions Pvt. Ltd. at the request of Ministry of Housing and Infrastructure for the proposed harbour rehabilitation project at L. Dhanbidhoo. L. Dhanbidhoo is located on the northern rim of Laamu Atoll and has a population of 800. The island economy depends mainly on agriculture. The existing harbour at the island was constructed in 90’s. The quay wall was constructed using corals. The quay wall had been badly damaged and the harbour has become too small to cater the large and deep draft vessels which call to the harbour. Hence the proposed project is to develop the existing harbour which can cater the growing demand for the vessels which will be using the islands for the next 15 years. The proposed harbour development project includes, construction of 197 m of quay on eastern, southern and northern side of the harbour using L blocks, deepening the harbour basin to – 3 at mean sea level, development of a harbour basin by 137 m long and 78 m wide, construction of 150 m rock boulder breakwater using dredged material as the core material. The project also includes deepening of the three access channels to a depth of – 3m at MSL. As part of the project, market lights would be place at the entrance channels. The excavation work of the project is expected to generate around 34,900 m3 of dredged materials of which 6,000 m3 is expected to be used as core materials of the breakwater, 12,000 m3 as back filling at the quay walls and 16,900 m3 to replenish the area of the beach on southern end of the harbour. 60 m long revetment would be constructed north and south of the harbour to protect the harbour from erosion. Environmental and socioeconomic impacts of the project were assessed. The impacts of the project result mainly from excavation of the harbour basin and entrance channel and disposal of excavated materials. The impact of excavation would be that of sedimentation. This impact is considered to be minor and short-term. Re-excavation of the entrance channels and harbour basin would have irreversible impacts. The project would help to address the current erosion problem by replenishing the eroding beach with the materials borrowed from the harbour basin. The socio-economic benefits of the project may be considered to outweigh the negative impacts of the project on the physical environment of the island especially increasing the usable space on the quay wall, mooring area at the island’s harbour and additional land that would be available to develop fish processing industry. The proposed project conforms to prevalent environmental legislation and thrives to achieve its objectives in an environmentally friendly manner. Mitigation measures for these anticipated impacts have been identified and outlined in detail, including sedimentation and stagnation control methods and measures for minimizing negative effects demolition of the quay wall and the generation of construction waste. These mitigation measures need to be followed in order to minimize environmental damage. The details of the project have been established after considering the needs and requirements of the community by assessing and incorporating the outcomes from the community consultations held during the data collection stage. The EIA also allowed to explore alternatives for the proposed development and identified key mitigation strategies. Alternative locations and alternative designs have been investigated for the different components of the project. However, the present project design seems to be a feasible option in terms of costs, durability and safety. An environmental management plan with environmental monitoring plan has been developed including important elements that require regular checks. This monitoring component will be adhered to and will allow the assessment of changes due to construction of the harbour. Although the project involves inevitable negative environmental impacts, such impacts are not severe as to not undertake the project. The project is justifiable in light of the socioeconomic conditions and anticipated benefits resulting from the project, which seem to outweigh the negative environmental impacts.