Flood Prevention Infrastructure

The Drainage Services Department is implementing a series of major flood control projects in the north-western and northern parts of the New Territories and in West Kowloon, costing about $13 billion.

In the north-western New Territories, improvement works to about 23 kilometres of the major river network have been completed, covering the lower and middle reaches of the Shan Pui River, the lower and middle reaches of the Kam Tin River near Yuen Long Nam San Wai, the Ngau Tam Mei main drainage channel, and the upper reaches of the Kam Tin River near Kam Tin San Tsuen and Shek Wu Tong. As a result, the flood risk in the surrounding areas has been relieved.

Construction of the Yuen Long Bypass Floodway and the San Tin eastern main drainage channel is in progress. Upon their completion in 2006, the flooding problem in Yuen Long new town areas will be resolved and the flood risk in San Tin reduced respectively. Design work for the San Tin western drainage channel is underway.

In the northern New Territories, the critical flood mitigation undertakings include the Shenzhen River Regulation Project and the rehabilitation of the River Ganges, which aimed at improving the downstream outlets for rivers in the Sheung Shui and Ta Kwu Ling areas. The Stage I and Stage II works of the Shenzhen River Regulation Project have been completed, and together with the completion of river training works in the lower and mid-stream of the River Indus and the River Beas, have basically eliminated the risk for formerly flood-prone villages in the Lo Wu, Tin Ping Shan and Ho Sheung Heung areas. The Stage III works of the project have started in phases since 2001 for completion in early 2006. These works include the training of four kilometres of the river's channel from Lo Wu to its confluence with the River Ganges.

To tackle the flooding problem in the Ta Kwu Ling area, drainage improvement works for 1.7 kilometres of the downstream of the River Ganges are progressing for completion in end 2005 to match with the completion of the Stage III works of the Shenzhen River Regulation. Design work for another 21.5 kilometres of drainage channels in the northern New Territories is also in hand, including the upstream portions of the rivers Ganges, Beas and Indus, and the Ma Wat and Kau Lung Hang channels. On completion of these remaining river training works, the regional flooding problem in the northern New Territories will be overcome.

In addition to the river training works, village flood pumping schemes have been implemented to protect low-lying villages from flood hazards. These schemes involve construction of bunds around villages and pumping of stormwater from within the bunded area to an outside channel during rainstorms. Altogether, 24 schemes are now in operation. Similar schemes for Mai Po, Lo Wai, Mai Po San Tsuen, Shui Pin Tsuen and Tai Kiu are under construction.

In West Kowloon, the Stage I drainage improvement which included laying about 10 kilometres of stormwater drains in Yau Ma Tei, Mong Kok, Kowloon Tong, Sham Shui Po and Lai Chi Kok, was completed in June 2003. The Stage II works which included improvements to about 23 kilometres of stormwater drains in Tsim Sha Tsui, Yau Ma Tei, Mong Kok, Sham Shui Po, Cheung Sha Wan and Lai Chi Kok, were substantially completed in December 2004. With the completion of the large flood storage tank underneath the Tai Hang Tung Recreation Ground in Mong Kok and the 1.5-kilometre stormwater transfer tunnel from Kowloon Tong to Kai Tak Nullah in 2004, the flooding problem in the Prince Edward area of Mong Kok has basically been resolved. The Stage III works, which included laying about 12 kilometres of stormwater drains in Yau Ma Tei, Sham Shui Po, Kowloon Tong and Yau Yat Tsuen, are progressing for completion in 2007.

To sustain the momentum given to flood control, the department has since 1994 completed seven out of eight Drainage Master Plan (DMP) Studies to review the condition and performance of the existing stormwater drainage systems in various flood-prone areas throughout Hong Kong. The last DMP study is due for completion in 2005. In view of current and future development needs, further packages of improvement works with greater focus on the secondary drainage networks have been included in the Public Works Programme and are at different planning and detailed design stages.

Under a preventive maintenance programme, the public drainage system is regularly inspected and desilted before and during the rainy seasons to ensure that stormwater is discharged effectively to prevent blockages and overflows which may cause flooding and nuisance to the public.

In 2004, the department maintained about 3 279 kilometres of watercourses, river channels and drains, from which about 283 870 cubic metres of silt were removed.

The importance of flood prevention is promoted through various public education activities. A newly furnished San Tin Flood Prevention Information Centre was opened in late 2004. Students and interested parties are welcome to visit the centre. Promotional pamphlets and advisory notes are published and distributed to villagers and property management offices before the rainy season. In addition, the department has organised site visits for District Councillors and the media to promote their understanding of the department's work and thereby enhance public awareness of the initiatives taken to prevent flooding.