Environmental impact assessment for undertaking coastal protection at Coastline Thilafushi Site, Thilafushi, Kaafu Atoll

Abstract

This report discusses the findings of an environmental impact study undertaken by Water Solutions Pvt. Ltd. for Coastline Investment Pvt Ltd. The project involves coastal protection works of the Thilafushi Coastline Site. The project aims to:  Protect the harbour basin in this site.  Provide safety and protection to the vessels accessing the harbour.  Deepen the existing harbour basin.  Increase the area of the site One of the challenges facing Coastline Thilafushi Site is lacking of protection to the harbour basin area. Therefore impacts of waves and storm surges on the basin create unsafe harbour condition in unfavourable weather conditions. This project aims to protect this area to provide safety for the crews and vessels operating here. Main components of the project include:  Construction of 146m rock boulder breakwater  Construction of 195.7m rock boulder revetment  Backfilling of the revetment for a width of 10m  Constructing a seawall on the lagoon side of the backfill area to retain sand from entering the basin  Dredging of existing basin to -3.5m during mean sea level  Reclamation of 1200m2 area Environmental impacts of this project were assessed and most of the environmental impacts of the project have been identified as resulting from the dredging and reclamation works. Dredging work will be undertaken using excavators and this is particularly a method that creates lot of sedimentation. Such coastal protection project that involves reclamation contributes to significant amount of sedimentation and it is the biggest threat to the marine environment. Mitigation measures for the negative impacts have been identified and outlined in the report. Sedimentation control methods have been specifically focused due to its seriousness. An important mitigation measure is the use of bund walls in the reclamation area to contain sedimentation and reduce its impact on the reef. In addition, completing the dredging and filling works in the shortest time frame is also a significant mitigation measure to minimize the impact of sedimentation on the marine environment. The proposed mitigation measures will have to be followed in order to minimize environmental damage. The measures proposed to minimize or mitigate environmental impacts may be considered to be appropriate, thereby minimizing the impact by about 90%. The main negative environmental impact of the proposed project would be sedimentation and destruction of the lagoon and damage to some areas of the nearby reefs, which will cause death of corals in the direct impact zone and partial death of corals in other areas of the coral reef. During dredging works, the sedimentation will also affect the fish species in the vicinity of these areas and hence, their population will drop in areas affected by sedimentation. It is inevitable that there would be negative environmental impacts of this project. As a result, a mitigation and monitoring component has been suggested which takes into consideration, the most important elements that require monitoring, most importantly a mechanism and means to measure and value the social benefit of the project. This monitoring component will be adhered and will allow the assessment of long term changes, despite the potential negative impacts. The coastal protection of Thilafushi Coastline Site does pose additional threats to the marine environment of the area. There will be direct and indirect damage to marine environment in the vicinity of the project site. However there are many positive benefits of the project in long term. This project is justifiable in the light of the positive impacts.