The Non Dredged Reclamation Method Environmental Sciences Essay

With the rapid economic and population growing, assorted economic, societal, lodging and conveyance demands of the community are increasing, ensuing in increasing demand for land supply. Due to the limited land supply, renewal is normally used to undertake the job in Hong Kong. However, renewal does non merely lend to the economic development but besides the environmental debasement. In this essay, jobs caused by renewal and possible solutions will be discussed.
As mentioned in Environmental Impact Assessment Report ( 2001 ) , dredging, disposal of Marine clay and majority filling activities may give rise to many possible impacts on H2O quality. First, solids may be suspended in the H2O column. Second, as clay moving ridges and turbulent flow will be generated, by perturbation, organic and inorganic substances e.g. ammonium hydroxide, heavy metals and sulfides may be released into the H2O column. Third, during the compacting and settling procedure in site formation, contaminations and leachate may be given out from pore H2O and deposits severally. As a consequence, the marine H2O quality will be deteriorated.
2.2 Marine ecosystem

Harmonizing to Chan ( 2000 ) , dredging and disposal of waste involved in renewal will convey inauspicious effects to the marine ecosystem. First, remotion of deposit may take to the loss of home ground. Second, marine beings may entrain during dredging. Third, dissolved O will be depleted and foods will be released into the H2O. In peculiar, if there is a important rise in the alimentary degree, algal productiveness will increase which may ensue in & A ; acirc ; ˆ?red tides & A ; acirc ; ˆA? .
2.3 Air quality
The job of air pollution will originate during the operation period of renewal as a big sum of dust will be emitted where the & A ; acirc ; ˆ?dust & A ; acirc ; ˆA? here refers to general suspended particulates. Among assorted sorts of beginnings of air pollution, earthmoving ( lading, droping and bulldozing ) , haul route traffic on unpaved roads and wind eroding of the unfastened site country lower the air quality the most ( Chan, 2000 ) .
Solutions
3.1 The non-dredged renewal method
Traditionally, the soft Marine clay in the ocean floor is replaced by sand fill to do a strong foundation for seawall building. Dredging and disposing of Marine clay are therefore involved. As the dredging procedure in renewal is the cardinal cause for the environmental impacts mentioned above, the non-dredged renewal method is advocated for the future renewal undertakings. Making mention to Hong Kong-Zhuhai-Macau Bridge Hong Kong Projects ( 2011 ) , this renewal method does non necessitate dredging the soft Marine clay in the ocean floor before backfilling. Alternatively, inert building and destruction stuff is used to make full many big interlocked steel cells. The steel cells will so drop in the H2O and remain on the alluvial sediment, organizing the margin wall. ( Items, 2011 )
As found in Items ( 2011 ) , the non-dredge renewal has many benefits over the conventional dredge breakwater building method. For case, dredging and dumping of Marine clay can be about wholly avoided. Besides, merely 30 % of the original suspended atoms will be released during renewal and merely half of the backfilling stuff will be needed. Thus the building Marine traffic can be decreased by about 50 % . It can be concluded that the non-dredge renewal method will convey less environmental impacts and therefore it is a better pick for renewal.
3.2 Development of belowground infinite
Enhanced usage of belowground infinite is an effectual and executable option to increase land supply as Hong Kong is cragged and abundant with strong volcanic and flinty stones. This geographic characteristic favors the development of belowground infinite in Hong Kong. Rock caverns can be developed for assorted land utilizations such as crematory, substation, sewerage intervention installations etc ( Hong Kong Underground Space Study Executive Summary, 2009 ) .
While both steps can alleviate the job of deficiency of available land, developing belowground infinite has some advantages over renewal. For illustration, some unwanted utilizations like garbage aggregation point can be built underground so that the impacts on the occupants populating nearby can be minimised. Furthermore, developing belowground infinite does non do much pollution or take away natural resources, which means that the natural environment can be preserved.
Decision
Though renewal can supply for the demands of the economic development, the conventional renewal method causes H2O pollution, air pollution and adversely affects the marine ecosystem, which is non an ideal act for the society. In order to strike a balance between economic growing and environmental preservation, the non-dredged renewal method should be adopted for future renewal undertakings as it is more environmentally friendly. In add-on to renewal, development of belowground infinite should be considered which can move as an option to increase land supply and reserve our valuable seaport.