Contract B is one of the major contracts managed by the Drainage Projects Division of Drainage Services Department, completed in 1998 to mitigate the flooding risk in the Yuen Long and Kam Tin drainage basin. Under the HK$284 million contract, a 3km long 150m wide trapezoidal channel is constructed from Castle Peak Road (Hung Mo Bridge section) to Nam Sang Wai where it joins with the downstream main drainage channel conveying the stormwater runoff to the Inner Deep Bay. Construction of roads, footpaths and waterworks are also involved.
To derive a harmony of appearance with the natural environment, the waterside is surfaced with grasscretes on which grass has now grown to produce a scenic green embankment on each side of the drainage channel.
A noteworthy ecological masterpiece is the planting of about 87,000 mangrove seedlings belonging to four different species in the tidal zone. This aims to re-create a wetland habitat for wetland creatures and migratory birds. The seedlings have been carefully selected and taken care of in the Futian National Nursery, and then transplanted onto the mangrove beds formed on the embankments. This ecological work of art has won recognition from some environmental organisations and horticultural institutions as well as commendations from the local villagers.
Resumed fish ponds alongside the drainage channel are also re-profiled with more stable pond bunds and re-filled with water suitable for fish-farming. They are an essential part of the Government's wetland compensation programme in the New Territories.