2. Yuen Long Bypass Floodway

Yuen Long Plain is a low lying area and was used to suffering from flooding frequently. In order to lower the risk of floods in Yuen Long town situated to the north of the plain, Yuen Long Bypass Floodway was constructed along the southern side of Yuen Long Highway, southeast of Yuen Long town. Yuen Long Bypass Floodway diverts the flow of Shan Pui River near the south of Yuen Long Town Centre to the new channel of Kam Tin River, in order to relieve the flood risk in Yuen Long Town Centre.

Yuen Long Bypass Floodway stretches some 3,800 metres, with a width of over 20 metres and a dry weather flow at the bed, and diverts 40% of rainwater of Yuen Long area to the new channel of Kam Tin River. Plant growth was artificially encouraged along the lower stream with "grasscrete". The surface of the concrete in this section was pierced with cavities, which were filled with soil, and vegetation was allowed to grow. Therefore, green plants thrive along the artificial channel, thus improving the appearance of the channel.

In addition to grasscretes, there is a shallow pond which is 350 metres in length and 1.8 hectares in area (equivalent to 18 full size swimming pools) constructed at the downstream of the Yuen Long Bypass Floodway. Various wetland plants are planted in the pond and along the banks to provide a wetland habitat for the flora and fauna, creating an ecological compensation for this project.

An inflatable dam is installed about 180m ahead of the confluence of Yuen Long Bypass Floodway and the new channel of Kam Tin River. It blocks the backflow of polluted river water to Yuen Long Bypass Floodway during high tides, so as to prevent nuisance-causing odour and rubbish from affecting nearby residents at the upstream area.

Yuen Long Bypass Floodway that you can see right ahead is a channel constructed by land excavation, as transforming the original rivers is no longer sufficient in dealing with the increase of discharge resulted from urbanisation.

River channel after rainstorm

Grasscretes in Yuen Long Bypass Floodway

A shallow pond in Yuen Long Bypass Floodway

Plants flourish in the Yuen Long Bypass Floodway

An inflatable dam installed in Yuen Long Bypass Floodway