7 COMPARISON BETWEEN THE TWO OPTIONS Deep Bay, southeast Lantau and Lamma areas. CWD sightings (and the areas of highest abundance) are common in the waters east of Lung Kwu Chau, between Lung Kwu Chau and Black Point, near Pak Chau, around the Brothers Islands and throughout the west Lantau area. Abundance is especially high along the stretch of waters between the Tai O Peninsula and Kai Kung Shan. CWDs are much less frequently observed in waters north of the HKIA platform, and in northeast Lantau waters. In broad terms, expanding the existing airport island northwards would overlay a marine area of low CWD abundance. Nonetheless, the reclamation could potentially impact on dolphins during both the construction and the operation stages, extending to loss of habitat, disruption of breeding and calving areas, and disturbance of activities such as feeding and socialising. A range of working methodologies, mitigation and compensation measures developed from other EIA studies over the years have been considered effective in minimising such impacts. All options for minimising, mitigating and compensating the potential impacts on CWDs would be fully investigated in the course of the statutory EIA process. Noise Impact on Noise Sensitive Receivers Residential communities along the flight paths are subject to a varying degree of aircraft noise. We follow guidelines established by the International Civil Aviation Organization (ICAO) and the United States Federal Aviation Administration (FAA), which indicate areas of aircraft noise exposure by using Noise Exposure Forecast (NEF) contours around an airport and its flight paths. According to the “Hong Kong Planning Standards and Guidelines” (HKPSG), noise sensitive uses such as domestic and educational premises should not be located within the NEF 25 contour. This is in line with the standards adopted by many developed countries. In 1998, we published NEF contours that represented a projection of the existing two-runway system operating at its design capacity. We have also conducted a preliminary projection of NEF 7.15 Figure Preliminary Projection of Three-Runway NEF Contours for HKIA 54