HONG KONG's outlying Lamma Island has commenced construction of a sub-marine sewage outfall at Yung Shue Wan which requires vessels navigating in the area to proceed with caution and at slow speed.
This action is intended to protect divers working in the area and to avoid collisions with ships deployed in the area. The works will continue over five months.
According to the Hong Kong Marine Department Notice No 39 of 2013, the sub-marine outfall construction works involve a backfilling operation. The installation of an outfall diffuser will be carried out in the area bounded by straight lines joining the coordinates (WGS 84 Datum) from (A) to (D) and the adjacent shoreline.
The co-ordinates are as follows: (A): 22?13.437' N / 114?06.463' E; (B): 22?13.603' N / 114?06.209' E; (C): 22?13.648' N / 114?06.242' E; and (D): 22?13.462' N / 114?06.530' E.
The works will be carried out by a flotilla of vessels including three derrick barges, one split hopper barge, some tugs and guard boats. The number of vessels engaged in the works will change from time to time to suit operational requirements, an official announcement said.
A working area of 30 metres around each barge will be established. Yellow marker buoys fitted with yellow flashing lights will be laid out to mark the positions of the anchors extending from the barges. Vessels engaged in the operation will display signals as prescribed in international and local regulations.
A silt curtain, extending from the sea surface to the seabed, will be established within the works area. The silt curtain is a large piece of netting used to contain mud and sediments. Yellow markers fitted with yellow flashing lights will be laid out to mark the extent of the silt curtain.
The hours of work is from 0700 to 1900 hours. No works will be carried out on Sundays and public holidays. Vessels used to carry out the works will stay in the area outside of working hours.