Reservoir Construction

Lam Tei Irrigation Reservoir was built by the Water Supplies Department in 1956. The reservoir has a 71.6m long, 21.0m high dam, a catchment area of about 2 square km, and a capacity of 115,000 m3. The dam separates the lower course from Lo Fu Hang, both hydrologically and ecologically. Also, the reduced flow has drastically weakened the self-purifying power of the lower course, making Tuen Mun River Channel susceptible to water pollution and sedimentation.




Lam Tei Irrigation Reservoir


Catchwater Diverting the River

The government built a catchwater on the western and southern slope of Kau Keng Shan, to intercept river water from upper course streams in the southeastern Tuen Mun Valley and channel the water to Tai Lam Chung Reservoir. The catchwater is a typical artificial channel, with the bottom and banks covered with concrete and a trapezoidal cross-section. The catchwaters cut off the natural streams, and the stream beds become mostly dry. The stream habitats are also fragmented. Moreover, catchwaters may connect different isolated drainage systems, and interfere with the hydrology of river basins.




Catchwater


Reclamation

In the 1970s, due to the development of Tuen Mun New Town, downstream of Tuen Mun River was undergone sea reclamation. "Tuen Mun River Channel", which passes flows through Siu Hong Court to Tuen Mun town centre. before the, this area was shallow sea known as Castle Peak Bay, just outside the estuary at Hau Kok Tin Hau Temple. extended the lower course of Tuen Mun River, which became today's "Tuen Mun River Channel". At the same time, streams that had originally fed into Castle Bay Bay were also extended by reclamation, becoming new tributaries of Tuen Mun River Channel. However, in the process these tributaries were mostly turned into underground waterways.



Tuen Mun River Channel was shallow sea before


Water Pollution

In the early days, without environmental regulations and sewage facilities, the large-scale industrial landuse in Tuen Mun New Town as well as numerous livestock farms in the villages discharged enormous amounts of untreated sewage into Tuen Mun River, causing severe pollution. Today, after years of efforts by the Environmental Protection Department (EPD) and other government departments, sewage from factories, villages, poultries and livestock farm and unlawful connection to stormwater drains are solved or under control. However, water quality problems persist, as some villages have yet to install sewage collection facilities and there are still expedient connections to the public sewers and the pollutants from stormwater drainage. Therefore, pollution problems of Tuen Mun River are yet to be completely solved.




Rubbishes from village polluted river water

Channelization

When Tuen Mun New Town was developed, the downstream of Tuen Mun River was channelised—straightened, deepened, widened and the riverbed and riverbanks were covered with concrete for increasing water flow to relieve flooding. The Drainage Services Department (DSD) built a dry weather flow channel along the middle of the nullah, to keep water flowing during low flows. Channelisation drastically altered the hydrology – changing flow, self-purification and river ecology of the lower course of Tuen River. Although flood prevention was achieved, other functions of a natural river were sacrificed, such as drinking water supply, irrigation, navigation, fisheries and recreational uses.




Dry weather flow of Tuen Mun River

Typhoon Shelter

Tuen Mun Typhoon Shelter locates at the south of Tuen Mun River estuary; it was built for fishing vessels that had moored in Castle Peak Bay due to development of Tuen Mun New Town. Mooring places, a wholesale fish market and cargo working area were also provided. Tuen Mun Typhoon Shelter is bounded by reclamation to the north and west, breakwaters to the east and south, making it an enclosed area of water. Pollutants carried by Tuen Mun River cannot be diluted and dispersed by sea currents, and are trapped in the typhoon shelter, worsening its water quality. Breakwaters weaken the flushing power of sea currents and tides, and lower the self-purification power of the lower course of Tuen Mun River Channel, leading to water pollution, and resultant ecological and odour problems.




Tuen Mun Typhoon Shelter


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