Managing Stormwater in Urbanised Singapore for Flood Control

Transcription

1 Managing Stormwater in Urbanised Singapore for Flood Control Flood and Storm Surge Control Training Tokyo, Japan Jan 2011 Singapore Representatives: Dorinda Hua / Senior Engineer 1 Loh Yee Wen / Engineer

2 Introduction 2

3 Singapore: Our Unique Circumstances Singapore Land Area ~710 km 2 Population Average Annual Rainfall Average Water Demand 4.99 mil 2,400 mm 1.6 mil m 3 /day 3

4 PUB Manages The Complete Water Cycle From sourcing, collection, purification and supply of drinking water, to treatment of used water and turning it into NEWater, drainage of stormwater Rain Sea Treatment of Used Water Direct Non- Potable Use Collection of Used Water in Sewers 4

5 Catchment & Waterways Department To plan, develop & manage our reservoirs & waterways for water supply & flood control and integrate them with the surrounding environment in a sustainable manner. optimise collection & storage of rainwater reduce flood-prone areas maintain good raw water quality in our reservoirs & waterways create value through integration of waterways & reservoirs with surrounding developments foster closer relationship between people & water 5

6 Floods Past and Now 6

7 The Blue Map of Singapore Some 7,000 km of roadside drains 32 major rivers 7

8 Types of Drains / Canals Outlet drain Open roadside drain Closed roadside drain Canal River 8

9 Physical Conditions Affecting Drainage in Singapore island generally flat with pockets of low lying areas affected by high tides increased stormwater runoff from urbanisation 350 AVERAGE MONTHLY RAINFALL (FROM 1869 TO 2009) annual rainfall of around 2400mm Amount of Rainfall (mm) main seasons dictated by monsoons northeast monsoon (Nov to Mar) southwest monsoon (May to Sep) 50 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month 9

10 Past Major Floods in Singapore No Record Amount of Rainfall (mm) Maximum 24 Hour Rainfall (1931 to 2009) Dec ,000 people affected 5 people died Tide level = 3.2m Total flooded area = 2540 ha Dec ,000 people affected 5 people died Tide level = 3.2m Total flooded area = 2750 ha Dec ,000 people affected 7 people died Tide level = 3.2m Total flooded area = 3178 ha Dec nurseries, 29 families, 1 club house & 4 shophouses Tide level = 3.0m Total flooded area = 12 ha Amount of Rainfall (mm) Year

11 Past Floods Potong Pasir, Dec 1954 Newton Circus, Dec 1969 Braddell Road, Dec 1978 Orchard Road, Dec ha in the 1970 s Bideford Road, Dec 1969 Braddell Road, Dec

12 Recent Floods Marina Station Road (10 Mar 2010) Localised and short floods Syed Alwi Road (26 Sep 2008) Sims Ave East near Lor Marican (12 Apr 2008) Coronation Walk (19 Nov 2009) 12

13 Stormwater Management in Singapore 13

14 Stormwater Management Objective Provide a first-rate drainage system to : harness rainwater for our water needs; and keep Singapore flood free. 14

15 How Do We Manage Flood Risks? PUB manages flood risks in three ways: 15

16 Reducing Flood Prone Areas 16

17 Approach to Managing Flood Risk (1) Provide adequate drainage ahead of new developments Plan and implement drainage systems and set aside drainage reserves based on current and projected land uses In consultation with other development agencies such as URA, HDB, LTA and JTC e.g. Sungei Punggol Implement flood alleviation projects to tackle and reduce the size of flood prone areas e.g. Marina Barrage 17

18 Approach to Managing Flood Risk (1) Provide adequate drainage ahead of new developments Plan and implement drainage systems and set aside drainage reserves based on current and projected land uses In consultation with other development agencies such as URA, HDB, LTA and JTC e.g. Sungei Punggol Implement flood alleviation projects to tackle and reduce the size of flood prone areas e.g. Marina Barrage Before After 18

19 Approach to Managing Flood Risk (1) Provide adequate drainage ahead of new developments Plan and implement drainage systems and set aside drainage reserves based on current and projected land uses In consultation with other development agencies such as URA, HDB, LTA and JTC e.g. Sungei Punggol Implement flood alleviation projects to tackle and reduce the size of flood prone areas e.g. Marina Barrage 19

20 Approach to Managing Flood Risk (1) Provide adequate drainage ahead of new developments Plan and implement drainage systems and set aside drainage reserves based on current and projected land uses In consultation with other development agencies such as URA, HDB, LTA and JTC e.g. Sungei Punggol Implement flood alleviation projects to tackle and reduce the size of flood prone areas e.g. Marina Barrage 3 in 1 project :- 1) Flood alleviation to act as a tidal barrier to control floods in the city 2) Water supply to be a freshwater reservoir 3) Lifestyle attraction vibrant waterfront with water based 20 activities

21 Approach to Managing Flood Risk (2) Adopting flood protection measures Stipulate the platform and crest levels required for new buildings and infrastructural facilities for flood protection purposes Raise low lying grounds / roads that were flood prone (in conjunction with redevelopment proposals) Advice on appropriate protection measures for older buildings Higher platform level for wafer fabrication plants 21

22 Approach to Managing Flood Risk (2) Adopting flood protection measures Stipulate the platform and crest levels required for new buildings and infrastructural facilities for flood protection purposes Raise low lying grounds / roads that were flood prone (in conjunction with redevelopment proposals) Advice on appropriate protection measures for older buildings BEFORE Kim Seng Road AFTER BEFORE Pan Island Expressway AFTER 22

23 Approach to Managing Flood Risk (2) Adopting flood protection measures Stipulate the platform and crest levels required for new buildings and infrastructural facilities for flood protection purposes Raise low lying grounds / roads that were flood prone (in conjunction with redevelopment proposals) Advice on appropriate protection measures for older buildings Flood Barrier 23

24 Approach to Managing Flood Risk (3) Making continual drainage improvement Continually reviewing and improving drainage in flood prone areas BEFORE AFTER Drainage improvement at Joan Road Outlet Drain 24

25 Maintenance of Waterways Keeping the drains and waterways free flowing and to operate drainage facilities Regular desilting of canals and rivers Cleansing of open roadside drains Trapping and removing flotsam & debris Float booms Mechanical debris removal facility Pumping stations & tidal gates 25

26 Maintenance of Waterways Keeping the drains and waterways free flowing and to operate drainage facilities Regular desilting of canals and rivers Cleansing of open roadside drains Trapping and removing flotsam & debris Float booms Mechanical debris removal facility Pumping stations & tidal gates Float Boom 26

27 Maintenance of Waterways Keeping the drains and waterways free flowing and to operate drainage facilities Regular desilting of canals and rivers Cleansing of open roadside drains Trapping and removing flotsam & debris Float booms Mechanical debris removal facility Pumping stations & tidal gates Pumping Station Tidal Gate 27

28 While the flood problems in Singapore are under control, we can still expect floods for two main reasons : low-lying areas where ground levels are barely above high tide are prone to flooding when heavy rain coincides with high tides. The only effective flood control measure is to raise the ground levels in conjunction with redevelopment there is a limit to which we can widen drains because of land constraints. Very intense rainfall can overwhelm the drains and cause flash floods. Such floods however will be minor and of short duration 28

29 Active Beautiful Clean (ABC) Waters Programme A. ACTIVE New recreational spaces B. BEAUTIFUL Integration of waters with urban landscape C. CLEAN Improved water quality Turn Singapore into a City of Gardens and Water PM Lee, ABC Waters Public Exhibition -Feb

30 Active Beautiful Clean (ABC) Waters Programme Long-term strategic initiative To transform our utilitarian drains, canals and reservoirs into vibrant, aesthetically pleasing and clean flowing streams, rivers and lakes To bring people closer to the water so that they will cherish and take ownership To create a seamless blue-green network well integrated with the adjacent developments MacRitchie Reservoir Kallang River Bishan Park 30

31 Active Beautiful Clean (ABC) Waters Programme Kolam Ayer ABC Waterfront After Before 31

32 Active Beautiful Clean (ABC) Waters Programme Sengkang Floating Wetland 32

33 Active Beautiful Clean (ABC) Waters Programme Lower Seletar Reservoir Family Bay Water Activities Family Bay Water Puppet Show 33

34 Flood Management in Singapore 34

35 Flood Management a) Keeping the public informed Preparing for the North East Monsoon Getting information Weather and Water Level Alert System b) Response and investigation into floods PUB s officers and contractors will step up inspections of drains in flood prone areas in Teams on standby when intense rain is forecasted preparation for the year end monsoon period. Teams on sites will render quick assistance to affected residents and motorists together with Traffic Police Flood advisories will be distributed to premises located in flood prone areas & who Investigate flood, identify cause and take immediate action have been affected by recent floods c) Extreme event of widespread flooding Flood advisories include: Dates Activate when high national tides are response greater than plan or equal includes to 3m (important rescue and for areas evacuation affected operations by floods coinciding with high tides) Singapore Police Force Lead agency in managing all joint operations Information involving on safety where and public security can obtain of public, information together on with weather, multiple water government levels, or other agencies pertinent information Websites, hotlines, contacts of flood board suppliers, etc. Suggestions on how to protect their belongings/premises 35

36 Flood Management a) Keeping the public informed Preparing for the North East Monsoon Getting information Weather and Water Level Alert System Information b) on Response how to Manage andflash investigation Floods is into floods available at PUB s Website Teams on standby when intense rain is forecasted Teams on sites will render quick assistance to affected residents and motorists together with Traffic Police Investigate flood, identify cause and take immediate action c) Extreme event of widespread flooding Activate national response plan includes rescue and evacuation operations Singapore Police Force Lead agency in managing all joint operations involving safety and security of public, together with multiple government agencies 36

37 Flood Management a) Keeping the public informed Preparing for the North East Monsoon Getting information Weather and Water Level Alert System b) Response and investigation into floods Heavy rain warnings currently Teams on standby when intense rain is forecasted issued on: Teams on sites will render quick assistance to affected residents and motorists together with Traffic Police NEA website Investigate flood, identify cause and take immediate action Radio SMS (to limited no. of c) Extreme event of widespread flooding recipients) Activate national response plan includes rescue and evacuation operations Water level alerts are currently issued via SMS Singapore Police Force Lead agency in managing all joint operations When sensor records water levels >75%, >90%, SMSes are sent out (to limited no. of recipients) involving safety and security of public, together with multiple government During flood events, agencies PUB works with Mediacorpto broadcast over radio the locations of flooded areas so that public can avoid these areas. Water level alerts for building owners/management committees in flood prone areas 37

38 Flood Management a) Keeping the public informed Preparing for the North East Monsoon Getting information Weather and Water Level Alert System b) Response and investigation into floods Teams on standby when intense rain is forecast Teams on sites will render quick assistance to affected residents and motorists together with Traffic Police Investigate flood, identify cause and take immediate action c) Extreme event of widespread flooding Activate national response plan includes rescue and evacuation operations Singapore Police Force Lead agency in managing all joint operations involving safety and security of public, together with multiple government agencies 38

39 Flood Management a) Keeping the public informed Preparing for the North East Monsoon Getting information Weather and Water Level Alert System b) Response and investigation into floods Teams on standby when intense rain is forecasted Teams on sites will render quick assistance to affected residents and motorists together with Traffic Police Investigate flood, identify cause and take immediate action c) Extreme event of widespread flooding Activate national response plan includes rescue and evacuation operations Singapore Police Force Lead agency in managing all joint operations involving safety and security of public, together with multiple government agencies 39

40 The Singapore International Water Week is the global platform for water solutions that brings policymakers, industry leaders, experts and practitioners together to address challenges, showcase technologies, discover opportunities and celebrate achievements in the water world. The event s flagship programmes comprise: Lee Kuan Yew Water Prize Water Leaders Summit Water Convention Water Expo Business Forums Details & Register at: 40

41 Thank you 41