Blue-Green Infrastructure

DSD has been striving to implement the concept of revitalising water bodies by incorporating green and eco-conservation elements into channel and river training works. These include planting in river channels and along riverbanks, engineering natural stream settings, preserving river ecosystems, enhancing various wildlife growth and introducing landscape designs, which promote greening, biodiversity and environmental beautification while maintaining the drainage capacity. For the purpose of blue-green infrastructure, we wish to create an environment with lush vegetation and beautiful waterscape for the public to get close to the water bodies and treasure the natural resources.

River Revitalisation – Rivers in Our Community

Drainage facilities built in the early years were mainly made of concrete and were designed for flood prevention. As time evolves, the public has more aspiration on water-friendly activities and gradually concerned with the importance of protecting water ecology and effective use of urban space. In response, we have been pushing forward a policy initiative in the 2015 Policy Address. In both large-scale drainage improvement works and the planning of drainage networks for New Development Areas, we have actively introduced innovative ideas for revitalising water bodies in nullahs and river channels.

Revitalising water bodies not only enhances the environment, but also enhances the river ecological value and biodiversity, as well as improves river greening. We will also strive to promote water-friendly activities so that the public can enjoy the river facilities and experience the value of multi-functionality of the water bodies so as to treasure the water bodies and jointly create a more livable environment.

River Revitalisation Elements

Ho Chung River and Upper Lam Tsuen River Improvement Works

DSD completed Ho Chung River and Upper Lam Tsuen River Improvement Works in 2007 and 2012 respectively, thus considerably alleviating the flood risk in the regions. Ho Chung River in Sai Kung and Lam Tsuen River in Tai Po are of great ecological significance. Myriads of wildlife, including bird, fish and dragonfly species, inhabit the two rivers. During construction, we did our utmost to minimise environmental and ecological impacts of our works and keep the land uptake during the river widening works to a minimum in order to preserve the original characters of the rivers.

Ho Chung River after the improvement works

Lam Tsuen River after the improvement works

Examples of conservation measures

Three zig-zag fish ladders in Upper Lam Tsuen River designed with still water troughs to provide refuge for fish

Gabion banks in Upper Lam Tsuen River, helps to promote plant growth and cultivate a natural ecology

Project team capturing the Hong Kong Newt before the Upper Lam Tsuen River Improvement Works

Deflectors in Ho Chung River includes variation in flow direction and velocity, which also creates zones of different water depths allowing various species to grow

Fish shelters in Ho Chung River provides refuge for fish and other aquatic animals during times of high tide and rapid flow

The Hong Kong Newt characterised by irregular orange ventral patches

Upon the completion of Upper Lam Tsuen River Improvement works, we deserved extensive plant growth on gabion banks and the natural riverbed, with a flourishing natural habitat, and the water quality was improved. These outcomes indicate that the conservation measures were effective. Moreover, the number of bird, fish and dragonfly species in the river were restored to the level before the improvement works and the Hong Kong Warty Newt, the rare species of Lam Tsuen River, was more abundant afterwards, all these results are encouraging.

Kai Tak River Improvement Works

Improvement works were carried out mainly to enhance the drainage capacity of the Kai Tak River. Upon completion of the works, Kai Tak River will meet the latest flood prevention design standards and be able to withstand rainstorms on the scale of a 200-year rainstorm, alleviating the flood risks in Choi Hung Road and surrounding area. In addition to upgrading drainage capacities, we are also taking this opportunity to incorporate aesthetic, greening, landscaping and ecological elements, thus revitalising the nullah into the first urban green river along a serene emerald corridor.

Not only did we install fish shelters and current deflectors at the river to reduce flow speed providing a refuge for fish inhabit, we also installed riverside planters, placed artificial rock planters and built submerged planters along the river allowing different types of plants growing on both banks to accentuate the greening effect. The revitalised Kai Tak River provides refuge for birds and fish with abundant greenery.

Kai Tak River after revitalisation

Egrets and herons roosting in Kai Tak River

Draping plant Bougainvillea spectabilis along the banks of Kai Tak River

Submerged planters with native mangroves species provide a wetland habitat

Revitalisation of Tsui Ping River

DSD plans to revitalise the nullah along Tsui Ping Poad and King Yip Street into Tsui Ping River. In sync with enhancing flood prevention capacity, we plan to revitalise the existing nullah with environmental, ecological and landscaping upgrading and enhance connectivity along the river and with the surrounding areas. Tsui Ping River will become a new landmark where the public can enjoy the river view and carry out leisure activities.

To manifest the characteristics of Tsui Ping River as a water body, we plan to install a smart water gate at the downstream to regulate the water level and create a waterfall effect. Such design utilises the natural tidal cycle to create waterscape, reducing the use on pumping facilities and hence lowering the energy consumption. On the other hand, the operation of the smart water gate will link to Hong Kong Observatory's weather forecast system, such that the smart water gate will be lowered during adverse weather conditions to maintain the hydraulic capacity of Tsui Ping River.

We will also provide along the riverside water-friendly features such as landscaped decks and a floating pontoon to promote water friendliness.

Illustration of the water gate and floating pontoon at the completed Tsui Ping River

Looking ahead Selecting Potential Nullahs and Rivers for Revitalisation

Meanwhile, we have reviewed and assessed major nullahs and rivers in Hong Kong with a view to identifying suitable nullahs and rivers channels for revitalisation. The revitalisation schemes of the Tai Wai Nullah (from Heung Fan Liu to Man Lai Court), Fo Tan Nullah (from Kwai Tei New Village to Hong Kong Sports Institute), and Jordan Valley Nullah (from Shum Wan Shan Pumping Station to Jordan Valley Swimming Pool) have been formulated. Revitalisation schemes will promote the co-use of river channels for other purposes in addition to their function as drainage facilities. Without affecting the drainage capabilities, we aim to demonstrate the multiple values of the water bodies and utilise the river spaces for the co-use of river channels.

Revitalisation of Tai Wai Nullah, Fo Tan Nullah and Jordan Valley Nullah

DSD plans to revitalise the existing Tai Wai Nullah, Fo Tan Nullah and Jordan Valley Nullah with aims to enhance the ecological value of the nullah, provide a greener environment, promote water friendliness and improve the community environment for building a livable city.

In Tai Wai Nullah revitalisation scheme, we will carry out an in-depth investigation on the feasibility of allowing the public to enter the river to conduct water friendly activities as a pilot scheme in order to provide the public with more large-quality-green spaces.

The walkability of the riverside footpath of the Fo Tan Nullah will be enhanced. Without affecting the drainage capacity and management of the river, we will consider utilising some river spaces to install community artwork for the public to view at the riverfront.

The downstream area of the Jordan Valley Nullah will be landscaped and a viewing platform will be built above the river to furnish a leisure space. In the upstream area, pools and fish ladders will be provided for ecological enhancement.

Conceptual picture of the revitalised Tai Wai Nullah

Conceptual picture of the revitalised Fo Tan Nullah

Conceptual picture of the revitalised Jordan Valley Nullah

Public Co-Use Facilities

In addition to river courses and drainage works, sewage treatment is also an important part of our work. As the community continues to develop, sewage treatment plants have gradually become close neighbors of the community. While upgrading the sewage treatment facilities to meet the development needs, DSD also attaches importance to the links with the community. In the design process, the community's inclusive elements such as public open space and landscape facilities are incorporated for the purpose of public enjoyment in the drainage facilities. The construction of a community-integrated livelihood facility will make drainage facilities more accessible to the public.

Shek Wu Hui Sewage Treatment Works (STW) will be upgraded to Shek Wu Hui Effluent Polishing Plant. Apart from expanding the plant to enhance the treatment level, facilities such as a bird watching area, a riverside promenade and an ecological garden, will be integrated into the Shek Wu Hui Effluent Polishing Plant improvement plan. The plan aims to utilise the surrounding natural environment and communities to provide a co-use space for the public to enjoy the beautiful scenery and stand close to the nature at River Sutlej and River Indus.

To this end, DSD has engaged a consultant to design and deliver a community-based co-creation project – “Community Design for Sustainable Development @ Shek Wu Hui Effluent Polishing Plant and the Peripheral Areas”. Using the methodology of design thinking, community members, educators, green groups and other professionals are invited to come together to co-design the co-use space and pre-registered visitor's area at Shek Wu Hui Effluent Polishing Plant.

Conceptual picture of green space and community plantation on the roof of the new workshop

Conceptual picture of riverside promenade adjacent to the new sludge treatment facility

Roof Greening

Roof greening can mitigate air pollution in urban areas, lower indoor air temperature, reduce building energy consumption, beautify building appearance and create wildlife habitats to improve biodiversity of the surrounding environment. During planning, we engage qualified persons to assess viable locations and their respective structural load-bearing capacities. Construction is carried out only after detailed design is completed. In 2018-19, we carried out roof greening for the following nine DSD facilities:

• Stonecutters Island Sewage Treatment Works – Polymer Storage Building

• Nam Wa Po Village Sewage Pumping Station

• Wai Tau Tsuen Sewage Pumping Station

• Kau To Sewage Pumping Station

• O Tsai Sewage Pumping Station

• Wah Fu Preliminary Treatment Works

• Aberdeen Preliminary Treatment Works

• Ap Lei Chau Preliminary Treatment Works

• Ngau Tam Mei Main Drainage Channel Pumping Station

Roof greening at Stonecutters Island Sewage Treatment Works Polymer Storage Building

Roof greening at Wah Fu Preliminary Treatment Works

Roof greening at Aberdeen Preliminary Treatment Works