The Obstacles to and Potentials for Increasing Riverine Ecosystem Services in High-Density Asian Cities: Hong Kong, Singapore, and Taipei

Transcription

1 The Obstacles to and Potentials for Increasing Riverine Ecosystem Services in High-Density Asian Cities: Hong Kong, Singapore, and Taipei Kuei-Hsien LIAO, Ph.D. Assistant Professor School of Architecture, Chinese University of Hong Kong

2 Shared characteristics of the three cities: Hong Kong Taipei Taipei City, Taiwan Hong Kong Special District of the People s Republic of China Economically highly developed Dense urban development Dominated by Chinese culture History of colonization Heavy western influences Sub-tropical/tropical climate Naturally flood-prone Relatively short rivers Singapore Republic of Singapore

3 Backgrounds of the study cities Hong Kong GDP per capita: S$38,124 Area: 1,104 km 2 Population: 7.2 million Overall density: 6,544 / km 2 Sewage treatment: 93% Singapore GDP per capita: $55,183 Total area: km 2 Population: 5.5 million Overall density: 7,615 / km 2 Sewage treatment: 100% Taipei GDP per capita: $23,374 Total area: km 2 Population: 2.7 million Density: 9,956 / km 2 Sewage treatment: 74%

4 Hong Kong Area: 1,104 km 2 Population: 7.2 million Overall density: 6,544 / km 2 Singapore Total area: km 2 Population: 5.5 million Overall density: 7,615 / km 2 Taipei Total area: km 2 Population: 2.7 million Density: 9,956 / km 2 Brisbane Total area: 15,826 km 2 Population: 2.27 million Density: 143 / km 2

5 Hong Kong Built-up area: 23.7% Density: 27,670/km 2 Singapore Built-up area: 60% Density: 12,721/km 2 Taipei Built-up area: 47.8% Density: 20,831/km 2

6 River management priority Hong Kong Singapore Taipei Flood control Flood control Flood control + Water supply

7 Current conditions of most urban streams and rivers Hong Kong Heavily channelized, concertized, culverted

8 Current conditions of most urban streams and rivers Singapore Channelized, leveed, culverted

9 Current conditions of most urban streams and rivers Singapore and dammed at the mouth

10 Current conditions of most urban streams and rivers Taipei Leveed, channelized, armored, culverted

11 Riverine ecosystem services Provisioning services Regulating services Cultural services Supporting services Fisheries & other food production Water supply Energy generation Water storage Flood hazard mitigation Water purification Carbon and nitrogen sequestration Temperature regulation Erosion/sediment control Recreation, aesthetic, and inspiration value Habitat & biodiversity

12 Hypothesized Riverine ecosystem services Provisioning services of highly modified urban streams and rivers In Hong Kong, Singapore, and Taipei Fisheries & other food production Water supply Except in Singapore Energy generation Regulating services Cultural services Supporting services Water storage Flood hazard mitigation Water purification? Carbon and nitrogen sequestration? Temperature regulation Erosion/sediment control Recreation, aesthetic, and inspiration value Habitat & biodiversity

13 Additional objectives Hong Kong Flood control Singapore Flood control Taipei Flood control Revitalizing Water supply waterbodies + Waterway enhancement Riverine environment rehabilitation

14 Additional objectives Hong Kong Flood control + Waterbody revitalization Singapore Flood control + Water supply + Waterway enhancement In reality, these objectives are far less important. Taipei Flood control + Riverine environment rehabilitation

15 Singapore The ABC Waters Programme Launch in 2006 It aims to transform the utilitarian drains, canals and reservoirs throughout Singapore into beautiful and clean streams, rivers and lakes with postcard-pretty community spaces for all to enjoy (PUB 2011: 4).

16 Singapore The ABC Waters Programme Stormwater Management + Waterway Enhancement Purpose: Removing the pollutants of stormwater runoff at source Measures: Bio-swale, rain gardens, green roofs, cleansing biotopes, constructed wetlands, etc. Purpose: Making the waterway an enjoyable place for people Measures: Riverbank greening, installation of decks, waterfront walkways, etc.

17 Singapore 2/3 of Singapore = Water-supply catchment area CBD area

18 Singapore More than 100 ABC Waters projects through 2030

19 Kallang River at Bishan-Ang Mo Kio Park Singapore Waterway enhancement Naturalizing the channel

20 Singapore Kallang River at Bishan-Ang Mo Kio Park

21 Kolam Ayer ABC Waterfront Project Singapore Waterway enhancement Greening, or softening the riverbanks Installation of decks Riverfront walkways Riverbank greening Installation of deck

22 Huang Creek Taipei Riverine environment rehabilitation Greening the riverbanks with ecological engineering Riverfront walkways

23 Daijia Riverside Park, Keelung River Taipei Riverine environment rehabilitation Developing riverfront recreational space, e.g., sports field, bicycle path.

24 Shezidao Wetland, Keelung River Taipei Riverine environment rehabilitation Floodplain wetland restoration

25 Lam Tsuen River (upstream) Hong Kong River rehabilitation Only occurs in the rural area.

26 The Kai Tak River Project Hong Kong Revitalizing waterbodies Greening and making recreational space Image source:

27 The Kai Tak River Project Hong Kong Waterbody revitalization Greening and making recreational space Image source:

28 Channel scale River restoration Catchment scale Stormwater management Driver Singapore Taipei Taipei Blue-green infrastructure Revitalizing waterbodies ABC Waters Programme Waterway enhancement Riverine environment rehabilitation Integrated Flood Management Water security Quality of life Flood safety Quality of life Wildlife conservation Flood safety Quality of life

29 Channel scale River restoration Catchment scale Stormwater management Driver Singapore Taipei Taipei Blue-green infrastructure Revitalizing waterbodies ABC Waters Programme Waterway enhancement Riverine environment rehabilitation Integrated Flood Management Water security Quality of life Flood safety Quality of life Wildlife conservation Flood safety Quality of life River restoration objectives (Bernhardt & Palmer 2007) Specific species Processoriented Ecosystem services

30 Geong Gye Cheong, Seoul A suitable model?

31 Geong Gye Cheong, Seoul A suitable model? Bishan - Ang Mo Kio Park

32 Hypothesized Riverine ecosystem services Provisioning services of highly modified urban streams and rivers In Hong Kong, Singapore, and Taipei Fisheries & other food production Water supply Except in Singapore Energy generation Regulating services Cultural services Supporting services Water storage Flood hazard mitigation Water purification? Carbon and nitrogen sequestration? Temperature regulation Erosion/sediment control Recreation, aesthetic, and inspiration value Habitat & biodiversity

33 Hypothesized Riverine ecosystem services Provisioning services of rehabilitated urban streams and rivers In Hong Kong, Singapore, and Taipei Fisheries & other food production Water supply Except in Singapore Energy generation Regulating services Cultural services Water storage in Taipei Flood hazard mitigation Water purification? Carbon and nitrogen sequestration Temperature regulation Erosion/sediment control in Taipei & Singapore Recreation, aesthetic, and inspiration value Supporting services Habitat & biodiversity

34 Obstacles to increasing riverine ecosystem services Water quality is still a concern (Hong Kong & Taipei) Flood control requirement Land availability Public perception (worries about flood risk) Governance: river health is no one s business

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36 Potentials for increasing riverine ecosystem services Increasing awareness of the role rivers and streams play in urbanism, e.g., increasing demand for recreational opportunities in the riverfront. Local runoff as an important source for water supply (Singapore). High density means a project could exert greater effects