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The Environmental Impact of Harbour Reclamation The older generation who lived in Hong Kong for many years would remember the Harbour by all the annual activities such as the exciting cross-harbour swim and the fun Dragon boat race. People would sit by the pier to catch and eat fish. Nowadays, Hong Kong people will not dare to imagine eating fishes caught in the stinking and health hazard harbour let alone swimming in it! Many of the harbour enjoyment have been taken away from us throughout the years due to harbour reclamation. Water and Sediment Quality The decline in harbour water quality was most dramatic in the 1970's due to industrialisation and the rapid growth of factories - electroplating, bleaching and dyeing, etc - around the harbour. These discharged toxic industrial effluents directly into the harbour with little or no treatment at all. Today, factories are required to treat their effluents before entering the harbour and due to high running cost in Hong Kong, many factories have relocated to the mainland. Toxins released over many years such as heavy metals and organic chemicals, are still buried in the soft mud on the harbour floor. Another reason for the deterioration has been the relentless increase in population living near the harbour. Any healthy marine ecosystem can absorb, and even thrive on, a certain amount of sewage. Hong Kong Harbour, however, passed its carrying capacity long ago. Gradual narrowing of the harbour from reclamation has reduced the flushing action of tides, whilst the number of toilets flushing into the harbour has increased. The result was poor water quality and limited marine life due to the lack of oxygen and high levels of bacteria and ammonia that gives the "famous" harbour smell that greets our visitors at the old Kai Tak airport. Only recently the government proposed new strategic sewage collection and treatment system before being discharged. The good news is that this has already resulted in significantly cleaner water especially in the eastern part of the harbour. Further reclamation will result in lesser flushing action, hence the harbour will remain at unhealthy levels. Natural Ecosystem The harbour is not only an access point for shipping, an open space for recreation and ventilation, and a tourist attraction but it is also a natural ecosystem. For hundreds of years it has been an important fishing ground and still today forms part of the natural marine and coastal habitat. While reclamation, dredging, over-fishing and pollution have taken their toll since the early habitation of Hong Kong Island, the harbour is still home to many sea creatures. Pink dolphins are occasionally seen, though more likely to be found to the west of Tsing Ma Bridge, and fishermen can still be seen trawling around the outer perimeters of the harbour. Schools of migratory whales used to be commonly spotted around the Ma Wan gap, and may still be occasionally seen today. Reclamation takes its toll on wildlife and the ecosystem in many different ways. The loss of natural coastline caused by reclamation results in a loss of important habitat and shallow feeding areas for many inter-tidal creatures that live in shallow sandy bays or on rocky shorelines. The hard straight unnatural seawalls that have been constructed along much of the harbour waterfront supports little wildlife. Thick layers of soft mud on the bottom of the harbour, heavily contaminated with heavy metals and organic chemicals - a legacy of Hong Kong's industrial past - are often removed by dredging before clean coarse sand is dumped for reclamation. The dredging stirs up the contaminated mud and releases some of those contaminants into the water, and consequently into the food chain. Fishing has been technically banned in the harbour but one must remember that fishes do not stay still in one place and tidal action results in contamination much further a field. Dangerous toxins can build up in the food chain, and eventually contaminate locally caught fish. The dredged mud - contaminated or not - is then barged off and dumped in an area near Chek Lap Kok airport, heavily used by the pink dolphins and near to a marine park. While Government's studies showed that dumping heavily contaminated mud into a hole on the seabed does not result in additional contamination of the area but surely this is not a sustainable activity! Lastly, the reclamation itself requires clean coarse sand, often dredged from different, more pristine parts of the ocean bed, often at the cost of coral and other bottom-dwelling organisms. Diagram: Schematic of impacts of reclamation on marine ecosystem
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