With the swift economic and population growth, various economical, social, housing and move needs of the community are increasing, resulting in increasing demand for land source. Because of the limited land resource, reclamation is commonly used to deal with the challenge in Hong Kong. However, reclamation will not only contribute to the economic development but also the environmental degradation. In this article, problems brought on by reclamation and possible alternatives will be discussed.
As pointed out in Environmental Impact Examination Statement (2001), dredging, disposal of marine mud and bulk filling activities may give rise to numerous potential influences on drinking water quality. Firstly, solids may be suspended in the water column. Secondly, as dirt waves and turbulent circulation will be made, by disturbance, organic and natural and inorganic substances e. g. ammonia, heavy metals and sulphides may be released into the water column. Thirdly, during the compacting and settling process in site creation, pollutants and leachate may get out from pore water and sediments respectively. As a result, the marine normal water quality will be deteriorated.
2. 2 Sea ecosystem
According to Chan (2000), dredging and disposal of waste involved in reclamation provides adverse effects to the sea ecosystem. First of all, removal of sediment can lead to the loss of habitat. Secondly, sea organisms may entrain during dredging. Finally, dissolved air will be depleted and nutrition will be released into the water. Specifically, if there is a significant surge in the nutritional level, algal efficiency will increase which can cause red tides.
2. 3 Air quality
The problem of polluting of the environment will arise during the operation period of reclamation as a large amount of dust particles will be emitted where in fact the dust here refers to general suspended particulates. Among various types of roots of polluting of the environment, earthmoving (loading, unloading and bulldozing), haul highway traffic on unpaved highways and breeze erosion of the open up site area lower the quality of air the most (Chan, 2000).
Solutions
3. 1 The non-dredged reclamation method
Traditionally, the tender marine dirt in the seabed is changed by sand fill to produce a strong base for seawall building. Dredging and losing marine mud are thus engaged. As the dredging process in reclamation is the fundamental cause for the environmental impacts mentioned previously, the non-dredged reclamation method is advocated for future years reclamation jobs. Making reference to Hong Kong-Zhuhai-Macau Bridge Hong Kong Projects (2011), this reclamation method does not require dredging the tender marine dirt in the seabed before backfilling. Instead, inert development and demolition materials is utilized to fill many large interlocked metallic cells. The metallic cells will sink in the and stick to the alluvium, developing the perimeter wall. (Items, 2011)
As found in Items (2011), the non-dredge reclamation has many benefits over the traditional dredge seawall development method. For example, dredging and dumping of marine mud can be almost completely avoided. Also, only 30% of the original suspended allergens will be released during reclamation and only one half of the backfilling materials will be needed. Thus the building marine traffic can be reduced by about 50%. It could be figured the non-dredge reclamation method provides less environmental influences and therefore it is a much better choice for reclamation.
3. 2 Development of underground space
Enhanced use of underground space is an effective and feasible option to increase land source as Hong Kong is mountainous and abundant with strong volcanic and granitic stones. This geographic characteristic favours the development of underground space in Hong Kong. Rock and roll caverns can be developed for various land uses such as crematorium, substation, sewage treatment facilities etc (Hong Kong Underground Space Analysis Executive Brief summary, 2009).
While both steps can relieve the situation of lack of available land, expanding underground space has some advantages over reclamation. For instance, some undesirable uses like refuse collection point can be built underground so that the influences on the residents living close by can be minimised. Additionally, producing underground space does not cause much pollution or take away natural resources, which means that the natural environment can be maintained.
Conclusion
Though reclamation provides for certain requirements of the economical development, the traditional reclamation method causes water pollution, air pollution and adversely affects the marine ecosystem, which is not an ideal take action for the contemporary society. In order to strike a balance between financial progress and environmental conservation, the non-dredged reclamation method should be adopted for future reclamation assignments as it is more green. Furthermore to reclamation, development of underground space is highly recommended which can become an alternative to increase land supply and reserve our valuable harbour.
