The major tributary
to the east of Tung Chung River converges with the
main stream very near the estuary. Its basin area,
length and flow volume are comparable with the main
stream. Hence it is often called East Stream, while
the main stream is called West Stream. East Stream
originates from the west of Sunset Peak at an altitude
of 815 metres, flows westwards down Sunset Peak, via
north Pak Kung Au at 220 metres above sea level, and
descends to the valley bottom, then flows near the
west of Tung Chung Road through Shek Mun Kap and Fong
Yuen before merging with the West Stream.
Tung Chung River is ringed by watersheds
on Nei Lak Shan (west), Lantau Peak (south) and the
northern ridge of Sunset Peak (east), with a basin
area of 11.09 km2. The West Stream has a dendritic
drainage pattern, with two major tributaries along
Nei Lak Shan east slope at Shek Pik Au. The East Stream,
on the other hand, has a rectangular drainage pattern.
The river valley is narrow and most tributaries are
short and enter the stream at right angle. A radial
drainage pattern is formed at the top of Lantau Peak
and Sunset Peak.