7.13 Figure Proposed Land Reclamation in Relation to Contaminated Mud Pits should minimise environmental impact as far as possible. In the course of the statutory EIA process, we will be able to address environmental concerns in detail. The following paragraphs briefly summarise the key findings of the preliminary environmental assessment of the recommended airport expansion layout under Option 2. the use of land on the existing airport island, thus keeping the requirement for new land reclamation to a minimum. The conceptual design of the expanded airport layout plan identifies that about 650 hectares of reclamation would be required. About 40% of the proposed reclamation falls upon an area of Contaminated Mud Pits (CMPs) – an area subject to substantial disturbance in the past and considered to be of low ecological value. This area was identified by the Government in 1991 as the preferred disposal site for contaminated dredged sediment, based on a Contaminated Spoil Management Study. Reclamation in this area cannot be carried out through the conventional “Undredged Hydrodynamics, Water Quality, Marine Ecology and Fisheries With the reclamation involved, Option 2 is undeniably associated with more environmental issues than Option 1. In planning Option 2, every attempt has been made to maximise with Vertical Drains” reclamation method as it involves potential release of polluted mud and leachate. Our consultants have recommended the “Deep Cement Mixing” reclamation method which has the advantage of minimising disturbance to the contaminated mud. While this method needs to be further considered in subsequent detailed studies, including on-site trials, it has been widely used overseas, particularly in Japan, where it is a well established means of improving the integrity of the soft ground and providing a robust foundation for reclamation. Hydrodynamic and water quality models from Delft Hydraulics have been used in a preliminary assessment of the potential impacts 7 COMPARISON BETWEEN THE TWO OPTIONS HKIA MASTER PLAN 2030 51