Reservoir Construction

The construction of Shing Mun Reservoir commenced in 1923, and was completed in 1936. A main dam was built at Shing Mun Gap, where Tai Shing Stream and Tso Shing Stream converged. Water from Tai Tso Stream and Sam Dip Tam Stream outside the natural river basin was also diverted via catchwaters to Shing Mun Reservoir. The water gathering ground of the reservoir has an area of 24.84 square kilometres. The main dam is 86 metres high and 213 metres wide, and separates the lower course from Tai Shing Stream and Tso Shing Stream, both hydrologically and ecologically.

Construction of Lower Shing Mun Reservoir started in 1961, and was completed in 1964. Its capacity is 4.3 million cubic metres. The main dam is 67 metres high and 229 metres wide and the area of the water gathering ground is 19.82 square kilometres. Lower Shing Mun Reservoir collects stream water from the north of Sha Tin Valley (including Shing Mun Gap, east of Needle Hill and southeast of Grassy Hill) as well as from Tai Po Kau Nature Reserve, Ta Tit Yan, Yin Ngam and Lin Au via water tunnels. Water from Plover Cove Reservoir can also be stored here, and will likewise be transported to Shatin Water Treatment Works. The hydrology and habitats of Shing Mun River were further fragmented and altered after Lower Shing Mun Reservoir was built.



Shing Mun Reservoir



Lower Shing Mun Reservoir

Catchwater Diverting the River

A 9-kilometre Shing Mun Catchwater was constructed, at an altitude of about 200 metres, near Chuen Lung to the west of Shing Mun Reservoir, to intercept streams flowing south from Tai Mo Shan and Sheung Fa Shan to Tsuen Wan and Kwai Chung, outside Shing Mun Valley, including Sam Dip Tam Stream and Tai Tso Stream. In addition, a 5-kilometre catchwater was also built to the north of the Lion Rock, from Sha Tin Tau New Village East, at an altitude of about 150m, to intercept streams north of the Lion Rock to Eagle's Nest – including Kai Hung Pak Hang, Kak Tin Hang and Hung Mui Stream – and divert their flows to Kowloon Reservoir. These streams originally flowed into Shing Mun River, but were diverted away from their natural watershed at Sha Tin Valley and towards Kowloon Reservoir. The natural hydrology is severely disturbed by the artificially connected waterways or even water systems. Catchwaters fragment the natural river habitats and disconnect the upper and lower courses, causing rivers below catchwaters to dry up, and eradicate whole ecosystems.




Shing Mun Catchwater (Photo taken Pineapple Dam Nature Trail)

Water Pollution

In the 1980s, Shing Mun River in Sha Tin was notorious for its severe pollution. All possible sources of wastewater entered the river: industrial and commercial activities, livestock waste, rural sewerage, sludge from water treatment works, and illegal wastewater drains. The river was black, filthy and foul, with low water quality and minimal self-purification capacity. It was in effect a dead river. Today, after years of efforts by government departments, the various river problems have basically been solved. Water quality has greatly improved and the river is slowly reviving.

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. In addition, non-point source pollution from Sha Tin New Town is increasing. Commercial and industrial activities in Sha Tin New Town – such as garages and restaurants – directly discharge waste oil, chemicals, sewage and food scraps into stormwater drainage. As a result, there are occasional reports of pollution of Shing Mun River.


Eutrophication occurred in Shing Mun Reservoir.

Non-point source pollution from Sha Tin New Town is increasing with the stormwater drainage. (Photo taken at Tai Wai)

Channelization

After entering Sha Tin New Town, or its lower course, Shing Mun River divides into three major sections, which have all been channelised: Tai Wai Nullah (the main channel), Fo Tan Nullah and Siu Lek Yuen Nullah. Other tributaries, such as Tin Sam Nullah and Kwun Yam Shan Stream, that are within the new town area have been converted to underground drainage, discharging water from the upper course of Shing Mun River Channel into Tide Cove. The estuary and coastal ecology has been completely destroyed.




Fo Tan Nullah (Photo taken at Yuen Wo Road, Fo Tan)

Tai Wai Nullah (Photo taken at Shing Chuen Road)

Reclamation

"Shing Mun River" is familiar to Hong Kong people, and refers to "Shing Mun River Channel" that flows through the town centres of Tai Wai, Sha Tin and Fo Tan. In the 1970s, before the development of Sha Tin New Town, the channel was shallow sea, or Tide Cove, just outside the estuary at Sha Tin Tau. Shing Mun River Channel was the result of reclamation. The original shallow sea was transformed into land with a river channel, and the natural coastline was ruined by reclamation, becoming the straight concrete and stone walls we see today.




Shing Mun River Channel (Photo taken at Sha Tin Park)


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