Environmental impact assessment for construction and development of water supply system at Dhangethi, Adh. Atoll

Abstract

The non-technical summary outlines the findings of the Environmental Impact Assessment of the construction and development of a freshwater production and distribution system at ADh. Dhangethi. The proponent of this project is the Ministry of Environment and Energy and total estimated cost of the project is MRF 17 million. To meet the water supply demand and to provide a quality treated water RO desalination with rainwater collection scheme is proposed for the island. The project involves the setup of a RO plant facility with two RO plants each with a capacity of producing 60m3 of freshwater per day One RO plant will be operational at anyone time while the remaining plant will be kept as a backup. Rainwater will be collected from the public buildings which will go through separate treatments before being mixed with RO desalinated water. Key impacts, mitigation measures and alternatives Impacts on the environment from various activities of the project development work (constructional impacts) and operational impacts 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 projects. Impacts were analysed for their significance with the aid of a Leopold Matrix. In any development project, major direct impacts to the environment occur mainly during the construction phase. Potential direct or indirect impacts on the environment from the proposed project include:  Minor to moderate impacts to the groundwater resource during drilling and construction work  Impact on vegetation due to the need to cut down vegetation located at the plot  Impact due to air and noise pollution during construction work  Impact on marine environment due to discharge of brine  Positive impact on social wellbeing and health Mitigation measures are discussed for the activities which would have potential impacts during the construction and operational phase of the project. In general, during the construction stage it is important to use a method of construction which has the least impact on the environment. Specific measures highlighted include following of established guidelines when carrying out excavation works and dewatering and transplantation of Coconut palms around the periphery of the project site. 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 these alternatives;  Location of RO plant facility  Source of feedwater for RO plant  Brine discharge location 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, this also means that the community would have to continue using only rainwater and groundwater as main freshwater sources. Additionally, it would also mean increased health risks faced by the community due to the use of contaminated water and the loss of potential additional job creation during the operation of the service. The environmental impacts predicted for the project are minor to moderate, hence the benefits of establishing the system, though with a cost to the environment is seen to be far more beneficial than the cancellation of the project, as the health risks faced by the community is not something that should and can be overlooked. Therefore the “no-project” scenario is not a feasible solution and it is recommended that the project be continued, but with the proper implementation of all mitigation measures proposed in the report. Details of the various alternatives considered and the selected alternatives are shown in Section 10 of the report.