This Section presents a summary of the key environmental outcomes arising from the EIAFSS, including the population and environmentally sensitive areas protected, environmentally friendly designs recommended, key environmental problems avoided, and the environmental benefits of the recommended environmental protection measures.
No unacceptable residual impacts are predicted for the construction and operation of the facility at the East of Sha Chau site.
The EIA study has facilitated the integration of environmental considerations into the design process for the Project. The principal measures identified are those achieved through pit and dredging design, and backfilling and capping working rates. In addition, a number of mitigation measures have been identified to minimise the potential for adverse environmental impacts. The mitigation measures are detailed in full in the Implementation Schedule (Annex E) and will be implemented by the Contractor under enforcement by the EPD.
One of the key environmental outcomes has been the ability to plan, design and ultimately construct the project so that direct impacts to sensitive receivers are avoided, as far as practically possible. A detailed assessment of alternative sites within the Study Area has been conducted. Through this assessment, environmentally sensitive areas have been protected by the following means.
· Avoidance of Direct Impacts to Ecologically Sensitive Habitats: The site for the East of Sha Chau Facility has been selected based on a review of the environmental considerations of the area and the most environmentally preferable site within the Study Area has been selected to avoid direct impacts to ecologically sensitive habitats and species.
· Avoidance of Indirect Impacts to Ecologically Sensitive Habitats: The site for the East of Sha Chau Facility has been selected so that it is located at a sufficient distance from ecological sensitive receivers so that dispersion of sediments from dredging, backfilling and capping operations does not affect the receivers. By locating the East of Sha Chau Facility in an area of low hydrodynamic energy the horizontal dispersion of suspended sediment is restricted to a confined area in close proximity to the pit boundary.
As a result, the assessments for this EIA have indicated that it is not expected that the construction and operation of the East of Sha Chau Facility will result in adverse impacts to environmentally sensitive areas.
A key concern in the final site and disposal option design was to take steps to ensure that both direct and indirect impacts through dredging, backfilling and capping operations were avoided or minimised. Consequently, the following approaches were adopted.
Adoption of Current Practices: A review of all environmental monitoring data collected since the commencement of operations at East of Sha Chau Contaminated Mud Disposal Facility has demonstrated that mud disposal activities at the East of Sha Chau area have remained within environmentally acceptable levels (). As all dredging, backfilling and capping operations proposed for the East of Sha Chau Facility have been designed to follow the current practices, no adverse unacceptable impacts are expected to occur.
· CMP Design: The East of Sha Chau CMPs have been designed as four separate pits, which minimises the exposure time of contaminated mud to the marine environment and consequently reduces the magnitude of any potential impacts.
· Adoption of Acceptable Working Rates: The modelling work has demonstrated that the selected working rates for the dredging, backfilling and capping operations will not cause unacceptable impacts to the receiving water quality. Consequently, unacceptable indirect impacts have been avoided.
Key environmental problems have been avoided through the detailed site selection process that, as discussed above, allowed environmentally sensitive areas and populations to be avoided. In addition, through the employment of practices that have been demonstrated to be environmentally acceptable, no unacceptable environmental problems are expected to occur as a result of the construction and operation of the proposed East of Sha Chau Facility.
The construction and operation of the proposed East of Sha Chau Facility will result in the temporary loss of low ecological value soft bottom habitat. Following the completion of capping operations, the seabed will be reinstated and is expected to return to pre-dredging conditions. As a result, compensation areas are not deemed necessary.
The design of the East of Sha Chau Facility will involve the dredging of purpose-dredged pits, backfilling with contaminated mud and subsequent capping with uncontaminated mud and/or natural uncontaminated soil to return the seabed and hydrodynamic regime to their original condition. A review of long term monitoring data from in and around the existing capped pits at East of Sha Chau has demonstrated that within a relatively short period of time, recolonisation of sediments occurs returning the site to a pre-dredged state. The employment of such environmental protection methods in the design of the East of Sha Chau Facility will, therefore, act as an environmental benefit.
This Environmental Impact and Final Site Selection Report has critically assessed the overall acceptability of any environmental impacts likely to arise as a result of the construction and operation of the proposed contaminated mud disposal facility at East of Sha Chau. Where necessary and practicable, the EIA has specified the conditions and requirements for the detailed design, construction and operation of the Project in order to mitigate environmental impacts to acceptable levels.
This EIA Study has predicted that the Project will comply with all environmental standards and legislation following the implementation of the recommended mitigation measures. The EIA has thus demonstrated the acceptability of any residual impacts from the Project and the protection of environmentally sensitive receivers and populations. Where appropriate, EM&A mechanisms have been recommended to verify the accuracy of the EIA predictions and the effectiveness of the recommended mitigation measures.
In conclusion, it is considered that the EIA provides a suitable basis for the Director of Environmental Protection to consider granting the Environmental Permit to allow the construction and operation of the Project.