Report of the EIA Subcommittee for October 1998
(ACE Paper 42/98)
The EIA Subcommittee considered and endorsed the EIA Report on 'Tsuen Wan Bay Further Reclamation, Area 35 - Engineering, Planning and Environmental Investigation' by circulation.
The EIA Report
This Report studies the feasibility of carrying out further reclamation in Tsuen Wan Bay. The proposed reclamation area covers 31 hectares and is aimed to meet the needs for housing supply by supporting a population of about 30000 by 2011 and to provide road links for improving the transport network in Tsuen Wan and Kwai Tsing districts.
The Report identifies major environmental impacts of the project on water quality, marine sediment disposal, traffic noise, exhaust emission and stack emission from Tsuen Wan and Kwai Tsing industrial areas. Recommended mitigation measures include special dredging and construction activities arrangement, marine sediment disposal scheme, preventive measures for possible methane gas generated, noise abating facilities and air quality assurance design.
Views and Recommendations of EIA Subcommittee's Members
A member enquired into the assessed risk of leakage and seepage of the highly contaminated materials which were proposed to be contained in-situ on site at the reclamation so that dredging activity would be limited to just a small scale at the seawall foundation. The project proponent, Territory Development Department, was also requested to advise the assessed reliability of the system in permanently isolating the contaminated mud from the environment.
In reply, the project proponent said that the quantity of contaminated mud to be placed would be small(less than 40,000 cu.m). There would be a 2m thick sand layer and another layer of public fill material of 5m to 15m thick on top of the mud. They advised that after the completion of reclamation, the contaminant would be very much contained underneath the reclamation. They also stated that possible impact from any seepage and leakage from the contaminated sediments during construction and consolidation stages had been assessed, and the results showed that the metal contaminant in the seepage water would be low and well within the UK water quality standards.
Another member asked the project proponent to guarantee the completion of the seawall construction before commencement of dredging and filling, as well as to test the pollution level of the disturbed marine clay. The project proponent responded that the marine clays had been sampled and analysed for contamination levels during the study. The proponent undertook to conduct further site investigation and testings during the detailed design stage.
Members of the Subcommittee were satisfied with the responses and no further enquiries were raised. They also agreed to endorse the Report by circulation.
Members are requested to advise whether the EIA Report should be endorsed.
EIA Subcommittee Secretariat