In the past, DSD emphasised a “three-pronged” approach: upstream stormwater interception and direct discharge to the sea, temporary flood storage via midstream storage tanks, and drainage improvements downstream, together with river regulation works, to mitigate flooding risks. Since 1995, a total of 127 flooding black spots have been eliminated as a result of these measures.

DSD continues to innovate and push forward with the concept of “Rivers in the City” to complement government initiatives in making Hong Kong an even more liveable city. DSD actively engages in river revitalisation works, in addition to ensuring suitable drainage capability of the rivers. Examples include improvement works in the Kai Tak River, the Upper Lam Tsuen River and the Ho Chung River. Serving beyond the purpose of flood prevention, these works help demonstrate the multifunctionality of water bodies. To build a green and liveable “riverside city”, DSD has formulated several schemes to revitalise existing river channels, including the Tsui Ping River and the Tung Chung Riverside Park, and is proceeding to evaluate the revitalisation potential of existing nullahs across Hong Kong.

In conjunction with the flood prevention infrastructure, DSD has also set up a 24-hour drainage hotline to deal with choked drains. During the 2019-20 reporting period, the hotline received about 31,900 cases requesting assistance. More than 99% were followed up within 24 hours, and customer satisfaction on the follow-up work exceeded 99%.

Photo montage of revitalisation of the Tsui Ping River.

Over the years, DSD has achieved remarkable results in improving sewage treatment. For instance, the “Harbour Area Treatment Scheme” (HATS) has significantly improved the water quality of Victoria Harbour. Apart from bringing the water quality up to the standard required for resuming the city’s cross-harbour race, HATS has also enabled the reopening of beaches adjacent to Tsuen Wan. Construction of dry weather flow interceptors (DWFI) in various districts to further improve coastal water quality is underway. DSD installed four DWFIs in coastal areas in Tsuen Wan in 2019 and is now carrying out construction works of four new DWFIs in Kowloon West.

Relocation of the Sha Tin Sewage Treatment Works to caverns.

Happy Valley Underground Stormwater Storage Scheme.

Today, DSD’s sewage treatment services cover more than 93% of the local population. The department has been extremely supportive of environmental protection initiatives. Its proactive involvement in the research and development of waste-to-energy technologies, coupled with its efforts in optimising existing sewage treatment facilities, is propelling Hong Kong towards its ambitious goals for carbon emission reductions. Among the facilities that mainly adopt biogas, hydropower and solar power for renewable energy sources, those that convert the flow of sewage into electricity are expected to produce up to 120,000 kilowatt-hours of electricity each year. In addition, DSD is testing the technology of co-digesting food waste and sewage sludge at the Tai Po Water Treatment Works to convert biogas into electricity. In the interim, DSD is relocating the Sha Tin Sewage Treatment Works to adjacent caverns to further promote sustainable development in Hong Kong. The relocation plan will vacate about 28 hectares of land for other uses that will benefit the community. With an advanced sewage treatment system, the new treatment works can be housed in the caverns, thus reducing the required land area for the facility to 14 hectares.

To help curb the spread of the Coronavirus Disease 2019 (COVID-19), DSD, the Environmental Protection Department, and the University of Hong Kong have formed a team of experts to help fight against the epidemic by adopting innovative methods in the research and development stage. Applying their professional knowledge to conduct drainage network analysis and devise sampling and testing plans, the team has successfully helped identify multiple asymptomatic carriers. The first confirmed case was also the first-ever success in detecting the COVID-19 virus in the community via sewage surveillance and mandatory testing orders. At this critical moment, DSD, in addition to performing its daily flood prevention and sewage treatment duties, has spared no effort in conducting sewage tests to help combat the epidemic together with all the efforts of the public.

The Chief Executive, Mrs Carrie Lam (second right), accompanied by the Secretary for the Environment, Mr Wong Kam-sing (first left), and the Director of Drainage Services, Ms Alice Pang (first right), visited a sewage sampling site set up by DSD.

Immediately after assuming the post of Director of Drainage Services (also being the first female director of a works department) in November last year, Ms Alice Pang was tasked with combating the challenges arising from the fourth wave of the COVID-19 outbreak in Hong Kong. DSD not only has to cope with the impact of the epidemic, but also has to maintain quality services in flood prevention and sewage treatment. At the same time, DSD must also take precautions to respond to the challenges brought about by various issues such as climate change — actively engaging in environmental protection and energy conservation, as well as exploring renewable energy options. Ms Pang upholds the people-oriented spirit of DSD and leads the team in continuously serving the public with excellence during this trying time.