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Tan Shan River, New Territories, Hong Kong

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Hong Kong, New Territories in Eastern-Asia, Hong Kong

Hok Tau and Lau Shui Heung Reservoirs, located in the upper course of Ng Tung River, were built in 1968, with the purpose of collecting and diverting water from nearby streams to Plover Cove Reservoir.

Meanwhile, some river water is used to irrigate adjacent farmland. This section of the river, named as Tan Shan River, is one of the main tributaries of Ng Tung River.

Tan Shan River is natural with excellent water quality, and it has been designated by the Agriculture, Fisheries and Conservation Department as an “Ecologically Important Stream”. The river supports a diversity of flora and fauna. Notably, it provides an important habitat for dragonflies.

Submitted by
Xavier Bourdet
Approved by
Fan Li & Zhou Hang
Geographical region
Eastern Asia
Drainage Basin
River catchment
Ng Tung River
Water body type
River
Water body name
Tan Shan River
Water body part
Water body course
Water body: tributary of
River
Tributary name
Ng Tung River

Videos above and below water

Water Chemistry

Water information

Water type
Fresh water
Water color
Clear water
Water transparency
High
Concentration of sediments
No
Water temperature
18-28.4°C °C
Water flow/curent
Strong

Chemical parameters

pH
7.5
Conductivity
GH
10 mg/l
KH
Dissolved Oxygen

Substrate in nature

Sand
White
Pebble/Gravel
no
Stone
Beige
Stone form
Roundish
Silt/Mud
no
Leaves
no
Driftwood
no
Submerged terrestrial vegetation
no

Aquatic Biotope

Date of collecting
Collecting area
Water depth
Air temperature
Sunlight

Environment

Environment
Untouched
Surrounding area

Hok Tau and Lau Shui Heung Reservoirs, located in the upper course of Ng Tung River, were built in 1968, with the purpose of collecting and diverting water from nearby streams to Plover Cove Reservoir. Meanwhile, some river water is used to irrigate adjacent farmland. This section of the river, named as Tan Shan River, is one of the main tributaries of Ng Tung River. Tan Shan River is natural with excellent water quality, and it has been designated by the Agriculture, Fisheries and Conservation Department as an “Ecologically Important Stream”. The river supports a diversity of flora and fauna. Notably, it provides an important habitat for dragonflies.

Ng Tung River is located in the northeast New Territories. The river catchment covers areas such as Lung Yeuk Tau, Fanling and Sheung Shui. Ng Tung River is a large tributary of the Shenzhen River System, and its own different tributaries bare different names, making the delineation of Ng Tung River Catchment complicated.

The river named as Ng Tung River on map originates from the southern slope of Robin’s Nest summit (492 m) at an altitude of about 450 m, and flows westward to Fu Tei Au. However, the actual origin of the main stream of Ng Tung River is from the west of Wong Leng summit (639 m) at an altitude of about 580 m. The main stream flows down the valley on the western slope of Wong Leng and goes into Hok Tau Irrigation Reservoir through Ping Shan Chai. It then turns northward to Tan Chuk Hang, and then westward merging with the tributary that originates from Robin’s Nest at Ko Po North Tsuen. This river section from Wong Leng to Ko Po North Tsuen is called Tan Shan River on the map.

The main stream of Ng Tung River merges with other major rivers in the region as it flows along. A few hundred meters to the west of Ko Po North Tsuen, the main stream merges with a tributary named Kwan Tei River.

The main stream continues westward and passes north of Lung Yeuk Tau before merging with a tributary named Ma Wat River. The main stream then passes northern Sheung Shui, and merges with two tributaries named Shek Sheung River and Sheung Yue River near Fu Tei Au. Finally, the main stream turns north and merges with Shenzhen River.

Underwater landscape

The landscape of Hong Kong is dominated by hills and ravines and flat land is restricted to the low floodplains and coastal regions. In this hilly domain, hundreds of small rocky streams flow through steep ravines.

These hill streams are typically fast flowing at their upland sources, and gradually reduce speed as they wind along hill cuttings to reach the lowlands. There are only a few long and meandering rivers in Hong Kong and are found only in the floodplains of the northern and northwestern NewTerritories.

There are over 2 500 km of natural streams and rivers in Hong Kong, mostly located in hillsides remote from developed areas.

Many of these natural streams and rivers are good habitats supporting a variety of wildlife. They have important ecological functions and carry high aesthetic and landscape value.
A natural stream or river refers to a natural channel with natural water fed from upper terrains, which covers both perennial stream and river with water flowing throughout the year as well as intermittent ones with water-flow only during the wet season.
The streambed is natural and not manmade, which could consist of mixtures of bedrocks, boulders, cobbles, gravels, sand, silt or clay. The banks are also largely natural and defined, covered with bank-side and riparian vegetation.

Fishes:

  • Anguilla japonica
  • Acrossocheilus parallens
  • Hypophthalmichthys nobilis
  • Barbonymus schwanenfeldii
  • Carassius auratus
  • Ctenopharyngodon idella
  • Pterocryptis anomala
  • Pseudogastromyzon myersi
  • Liniparhomaloptera disparis
  • Misgurnus anguillicaudatus
  • Zacco platypus
  • Puntius semifasciolatus
  • Parazacco spilurus
  • Cyprinus carpio
  • Clarias  fuscus
  • Silurus  asotus
  • Channa striata
  • Channa maculata
  • Channa gachua
  • Channa asiatica
  • Macropodus opercularis
  • Anabas testudineus
  • Rhinogobius giurinus
  • Rhinogobius duospilus
  • Coptodon zillii
  • Oreochromis niloticus
  • Oreochromis mossambicus
  • Monopterus albus
  • Xiphophorus variatus
  • Xiphophorus helleri
  • Poecilia reticulata
  • Gambusia affinis
  • Clarias gariepinus

There are also a species of:

  • Mollusc: Sulcospira hainanensis
  • Crustacean: Macrobrachium hainanense
  • Amphibian: Paramesotriton hongkongensis 
Threats to ecology

Riparian zone

Trees near the aquatic habitat
Many - Not Identified

Comment by the expert

Fan Li: The participant provided detailed description about fish communities in this habitat.