Environmental Impact Assessment for Proposed Replacement Causeway for Foa Island, Kingdom of Tonga

Abstract

The purpose of the action is to improve transportation and reduce maintenance cost by upgrading causeway between Foa and Lifuka Islands, to become more resilient and less vulnerable to impacts of high energy waves. Built in the period 1978-1979, the raised coral structure has served the people of Foa and Lifuka well despite increasing maintenance cost. The replacement structure is similar to the existing one but with rock armoring to reduce the energy of waves impacting on the structure and culverts in the middle to encourage water flows to the western side of the Causeway. The estimated cost of construction is about TOP4.67 million. Environmental effects requiring specific analysis are limited to the followings; · possible effect of the structure on coastal erosion · dispersion of fine sediment from the construction site and its possible effects on fauna and flora in the nearby areas. Other effects considered in the analysis include social issues on fisheries and tourism, health issues on fish poisoning and on biological communities of the areas.