Environmental impact assessment for establishment of an integrated water management system in R. Maduvvari

Abstract

This report discusses the findings of the Environmental Impact Assessment (EIA) study undertaken by Ministry of Environment and Energy to develop a Integrated Water Resource Management (IWRM) system at the Maduvvari Island in Raa Atoll. This report is prepared in accordance with Environmental Impact Assessment Regulation (2007) under the Environmental Protection and Preservation Act (1993) and the Amendments to the EIA regulation. The purpose of this EIA report is to fulfill the requirements of the aforementioned law and regulation and conduct an assessment of possible impacts on the ecological, biophysical and socioeconomic environment arising from the proposed IWRM project in R. Maduvvari Island. The main rationale of this project is to develop and operate an IWRM system in R. Maduvvari Island. R. Maduvvari has limited capacity to for storage of rainwater and faces drinking water shortage during the dry period. The proposed system is aimed to produce and supply fresh water for the island community throughout the year. Furthermore, there is an existing sewerage system which is operational without a provision of the sewerage treatment plant, hence the groundwater lens of the island is facing saltwater intrusion due to extraction of water for flushing purpose. There are no existing mechanisms for replenishment of groundwater since the R. Maduvvari lack a proper drainage system. The proposed IWRM project includes a groundwater recharging mechanism which is expected to improve the quality of the groundwater in R. Maduvvari. The project will involve establishment of rainwater harvesting collection and conveyance system, installation and operation of Reverse Osmosis Plants and construction of a piped water network with household connections. Key Impacts The project will involve impacts both during the construction and the operational phase of the project. The main project activities which may result in impacts during the construction phase include; installation of brine reject outfall. The brine reject outfall installation is expected to have impacts on the marine habitats found in the vicinity of the location. However, there are very few live coral colonies near the proposed location for the brine reject outfall. Another main project activity which may have a significant impact on the environment include; land clearance. However, in R. Maduvvari there are very few sparely spread vegetation found in the project area. No protected trees are located in the project location. There are no major threats to terrestrial and marine biodiversity of the island due to the proposed IWRM project in R. Maduvvari. The other project activities which may have an impact include excavation and pipe works on land, impacts of machinery and equipment, impacts of the workforce and drilling of a borehole. The main project activities during the operational phase which is envisaged to have the most signifincat impact is brine disposal. However, the brine will be disposed through a brine reject outfall into open ocean which have high mixing potential due to strong currents away from the island. The other project activities which may have impact on the biophysical environment of R. Maduvvari include operation of pumps and RO plants, water treatment and disinfection, piped water network and water testing chemicals (handling & storage). The major socioeconomic impact is found to be positive. The provision of the clean and safe drinking water throughout the year will improve health of the island community. Furthermore, it is anticipated that the access to clean and safe water will increase the economic opportunities for the island community of R. Maduvvari. Mitigation Measure The mitigation measures were proposed based on conducting appropriate field surveys and environmental assessment of the R. Maduvvari Island, proposed and alternative locations for the brine reject outfall and project site. The main mitigation measures during the construction phase include ensuring proper supervision and monitoring during excavation and pipe-laying works. The installation of the brine reject outfall can be conducted only during the low tide period to reduce the sedimentation and the impacts on the marine life in close proximity to the brine reject outfall location. The impact of the machineries can be reduced by using experienced operators to conduct the excavation works. Furthermore, local contractors and employees can be employed rather than the expatriate workers which will reduce the impacts of the workforce on biophysical and socioeconomic environment of the island. Planting trees to offset the trees removed from the project site is an important mitigation measure to reduce the impacts of the land clearance. The environmental impact of drilling a borehole to obtain feedwater can be reduced by contracting experienced contractors who have extensive experience in drilling boreholes in Maldives. The main mitigation measures to be taken during the operation phase of the project include training of staff to be employed in the laboratory and operation of the IWRM system regarding safe handling of chemicals and appropriate quantities of chemicals to be used for disinfection. Another significant mitigation is installation of diffusers in the brine reject outfall which will enhance the mixing of the brine reject thus reducing impacts of the brine disposal. Alternate locations and technology Alternative systems for IWRM system, alternative to drilling a borehole and alternative locations have also been considered during the assessment. Alternative locations for the project location, location of the brine reject outfall was also considered. The alternative system to IWRM were not considered since they are found to have more significant on the environment and also costly. The alternative to drilling a borehole is to obtain feedwater from the lagoon which will increase maintenance cost and cost for desalination. The alternative location proposed will involve loss of more corals and habitats for other marine organisms and also involves removal of more trees. Environmental Management and Monitoring An environmental management plan with environmental monitoring was developed taking into consideration the impacts and mitigation measures to be implemented. The important elements that require checks such as groundwater quality, coral cover, seawater quality will be monitored according to the developed monitoring program during construction and operation period. Although the project involves inevitable negative environmental impacts, such impacts are not serve as to not undertake the project. Mitigation measures have been proposed to adequately minimize the significant impacts. Hence, the project is justifiable in light of the socioeconomic conditions and anticipated benefits from the project which clearly outweigh the negative environmental impacts.