Environmental impact assessment report : flood mitigation project at Holhudhoo, Noonu Atoll

Abstract

The non-technical summary outlines the findings of the Environmental Impact Assessment of the proposed development of flood mitigation measures on Holhudhoo. The proponent of the proposed project is Ministry of Environment and Energy. The total estimated cost of this project is MRF 8million. Flood mitigation will be through the construction of Box culvert from the flood zone at the NW side of the island to the west along with a backup lifting station. Key impacts, mitigation measures and alternatives Impacts on the environment from various activities of the construction work and during the operation of the facility 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. Possible impacts arising from the project are categorized into reversible and irreversible impacts. The impacts identified are also described according to their location, extent and characteristics. Mitigation measures have also been identified for impacts which are irreversible in nature. In any development project major direct impacts to the environment (either short-term or long-term) occur mainly during the construction phase, while some impacts are inevitable during the operation stage. Impact analysis was done using the Leopold matrix. Impact analysis showed the project to have few minor impacts on the environment: ➢ Impact on groundwater resource due to dewatering during construction and due to drainage of floodwater during operational phase (which currently is allowed to seep into the ground and into the water lens) ➢ Impacts on structural stability of the buildings during construction ➢ Impacts due to noise and other disturbances ➢ Pollution of the natural environment ➢ Accidents and risk on workforce Key impact during the operational phase is the major positive impact through mitigation of flooding issues during surge and heavy rainfall. This in return increases the safety and security of the island community and infrastructure from such events. Mitigation measures are discussed in the report for potential impacts, including the protection of boundary walls of buildings at curbs through shoring works, so as to minimize or avoid damage to these structures. Mitigation has also been considered for the event that the project might be stopped prior to the completion of all works. In such cases, it is advised to ensure that the mitigation measures outlined for this scenario in Table 10 are implemented prior to the departure of contractors. Detailed mitigation measures are discussed in Section 11 of the report. Alternatives have been considered for various components of the project and are given as possible options that may be either more practical or less expensive to the preferred options. The proposed alternatives also have taken into consideration the environmental consequences resulting from these options as compared to the preferred options. The following components of the project have been discussed in providing their alternatives; ➢ Project design ➢ Location of outfall The no-project scenario is also considered, which would mean that all environmental impacts due to the project would no longer be an issue. However, discontinuation of the project is not feasible as this continues to leave the island at risk to issues faced due to flooding during heavy rainfall and surge periods, such as damage to infrastructure and property at flood prone area and risk to wellbeing of island community. Given that the environmental impacts due to construction work are minor and few, while the benefit is major and significant, the Consultant feels that the project can be continued, with minimal impact on the environment, especially with implementation of the mitigation measures given in the report