> Preserving Hong Kong's Natural
Heritage... > Protecting
the Environment for All > Kai
Tak Airport North Apron Decontamination > 1,800
Mega Watt Extension... > West
Rail > International Theme
Park... > Removal of Sediment
in Cheung Sha Wan Fish Culture Zone > Cyberport
Development at Telegraph Bay > Felling
of Five Chimneys at Tsing Yi Power Station > KCR
East Rail Extension > East
of Sediment in Cheung Sha Wan Fish Culture Zone
sealed mechanical grabs to minimise spillage.
Silt curtains were installed at the dredging site next to
the fish culture zone
The Cheung Sha
Wan Fish Culture Zone is located near Chi Ma Wan Penunsula off the
coast of Lantau Island. Bottom sediment under the Cheung Sha Wan
Fish Culture Zone (FCZ) contains a large amount of organic matter
accumulated over the years. The organic sediment adversely affects
the surrounding marine habitats, the associated marine life and
the productivity of the FCZ.
To achieve improvements
in the marine environment, the removal of bottom sediments at FCZ
by dredging was proposed. The zone area and dredged area of Cheung
Sha Wan FCZ were 214,200m2 and 228,000m2.
The proposed sediment volume to be dredged was about 147,000 m3,
and the average dredging rate was 175 m3/hr. The removal
of anoxic sediments and the bulk of trapped nutrients would improve
the local water quality and reduce the risk of local red tide and
upwelling of anoxic and toxic gases.
Permit (EP), EP-008/1998, was issued on 9 November 1998 and conditions
set out in the Permit were implemented. Site inspections were conducted
during construction and post project monitoring. The dredging work
was started on 20 November 1998 and completed on 20 January 1999.
Mitigation Measures and Outcomes
Silt curtains were installed between the dredging site and the
temporary relocation site and placed not more than 100 metres
away from dredging operation throughout the dredging process.
To shorten the period of disturbance to the FCZ and the environment,
the dredging operation was carried out within the shortest time
possible and finished within two and a half months.
Mechanical grabs were used throughout to avoid spillage and to
seal tightly while being lifted.
Barges and grab dredgers were fitted with tight-fitting seals.
Adequate freeboard was maintained on barges to prevent spillage
of material into the sea.