Water Pollution

The abundant water and fertile soil have long attracted people to settle around Lam Tsuen.

In the early days, when there were no controls on waste treatment, farmers along the upper course of Lam Tsuen River directly discharged livestock waste into the river. Until recent years, there was still no public sewage system in villages in Lam Tsuen valley, and even today sewage from some old village houses flows directly into the river through open channels.

Pollution of the lower course is mainly from commercial and industrial activities - such as garages and restaurants - in Tai Po. Waste oil, chemcials, wastewater and food scraps are discharged directly into stormwater drainage, eventually reaching Lam Tsuen River.

Some people also dispose of rubbish in the river. The downstream section of Lam Tsuen River is little more than a dirty gully.

The lower course is filled with rubbish.

Channelization and Flood Control

To solve flooding problems, part of the middle and lower courses of the natural river has been channelized. Channelization straightened the natural and meandering river, and deepened and widened the riverbed. It increased the carrying capacity of the new channel, hence containing floodwaters that originally overflowed onto the floodplain, and discharging the water into the sea within a short period.

To reduce water resistance and make it convenient to maintain, the riverbed and river banks are mostly covered with concrete. The channel after Tai Po Tau of Lam Tsuen River has been straightened into a flood control ditch made of bricks and concrete.

River works not only alter the appearance of natural rivers, they also change the river structure.

(1) Hydrological impacts

Channelization directly increases the flow rate and flow volume of the river. It also disconnects the river from underground water, leading to an extreme river hydrology. During dry seasons, the concrete surface prevents underground water from entering the river. During rainy seasons or rainstorms, overflowing water cannot seep underground.

(2) Impacts on Water Quality and Ecology

River training projects convert the riverbed and riverbanks into concrete. Water flow and temperature are no longer be suitable for most of the original flora and fauna, including microorganisms. The populations of different species decrease, and the river ecology is severely damaged. The self-purification ability of the river is greatly reduced, and the water quality deteriorates.

(3) Other Impacts

Lam Tsuen River is among Hong Kong's few remaining natural rivers with relatively complete river geomorphology and ecology, which can serve as educational and research resources for subjects including hydrology, ecology, geography, and urban planning. Yet past river works have already ruined many of the natural resources and geographical features. We have lost a wealth of scientific and educational resources.

Artificial channel at Ma Po Mei

Artificial channel at Mui Shue Heng

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